fs/btrfs/inode.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Copyright (C) 2007 Oracle.  All rights reserved.
   4  */
   5
   6 #include <linux/kernel.h>
   7 #include <linux/bio.h>
   8 #include <linux/buffer_head.h>
   9 #include <linux/file.h>
  10 #include <linux/fs.h>
  11 #include <linux/pagemap.h>
  12 #include <linux/highmem.h>
  13 #include <linux/time.h>
  14 #include <linux/init.h>
  15 #include <linux/string.h>
  16 #include <linux/backing-dev.h>
  17 #include <linux/writeback.h>
  18 #include <linux/compat.h>
  19 #include <linux/xattr.h>
  20 #include <linux/posix_acl.h>
  21 #include <linux/falloc.h>
  22 #include <linux/slab.h>
  23 #include <linux/ratelimit.h>
  24 #include <linux/btrfs.h>
  25 #include <linux/blkdev.h>
  26 #include <linux/posix_acl_xattr.h>
  27 #include <linux/uio.h>
  28 #include <linux/magic.h>
  29 #include <linux/iversion.h>
  30 #include <asm/unaligned.h>
  31 #include "ctree.h"
  32 #include "disk-io.h"
  33 #include "transaction.h"
  34 #include "btrfs_inode.h"
  35 #include "print-tree.h"
  36 #include "ordered-data.h"
  37 #include "xattr.h"
  38 #include "tree-log.h"
  39 #include "volumes.h"
  40 #include "compression.h"
  41 #include "locking.h"
  42 #include "free-space-cache.h"
  43 #include "inode-map.h"
  44 #include "backref.h"
  45 #include "props.h"
  46 #include "qgroup.h"
  47 #include "dedupe.h"
  48
  49 struct btrfs_iget_args {
  50         struct btrfs_key *location;
  51         struct btrfs_root *root;
  52 };
  53
  54 struct btrfs_dio_data {
  55         u64 reserve;
  56         u64 unsubmitted_oe_range_start;
  57         u64 unsubmitted_oe_range_end;
  58         int overwrite;
  59 };
  60
  61 static const struct inode_operations btrfs_dir_inode_operations;
  62 static const struct inode_operations btrfs_symlink_inode_operations;
  63 static const struct inode_operations btrfs_dir_ro_inode_operations;
  64 static const struct inode_operations btrfs_special_inode_operations;
  65 static const struct inode_operations btrfs_file_inode_operations;
  66 static const struct address_space_operations btrfs_aops;
  67 static const struct file_operations btrfs_dir_file_operations;
  68 static const struct extent_io_ops btrfs_extent_io_ops;
  69
  70 static struct kmem_cache *btrfs_inode_cachep;
  71 struct kmem_cache *btrfs_trans_handle_cachep;
  72 struct kmem_cache *btrfs_path_cachep;
  73 struct kmem_cache *btrfs_free_space_cachep;
  74
  75 #define S_SHIFT 12
  76 static const unsigned char btrfs_type_by_mode[S_IFMT >> S_SHIFT] = {
  77         [S_IFREG >> S_SHIFT]    = BTRFS_FT_REG_FILE,
  78         [S_IFDIR >> S_SHIFT]    = BTRFS_FT_DIR,
  79         [S_IFCHR >> S_SHIFT]    = BTRFS_FT_CHRDEV,
  80         [S_IFBLK >> S_SHIFT]    = BTRFS_FT_BLKDEV,
  81         [S_IFIFO >> S_SHIFT]    = BTRFS_FT_FIFO,
  82         [S_IFSOCK >> S_SHIFT]   = BTRFS_FT_SOCK,
  83         [S_IFLNK >> S_SHIFT]    = BTRFS_FT_SYMLINK,
  84 };
  85
  86 static int btrfs_setsize(struct inode *inode, struct iattr *attr);
  87 static int btrfs_truncate(struct inode *inode, bool skip_writeback);
  88 static int btrfs_finish_ordered_io(struct btrfs_ordered_extent *ordered_extent);
  89 static noinline int cow_file_range(struct inode *inode,
  90                                    struct page *locked_page,
  91                                    u64 start, u64 end, u64 delalloc_end,
  92                                    int *page_started, unsigned long *nr_written,
  93                                    int unlock, struct btrfs_dedupe_hash *hash);
  94 static struct extent_map *create_io_em(struct inode *inode, u64 start, u64 len,
  95                                        u64 orig_start, u64 block_start,
  96                                        u64 block_len, u64 orig_block_len,
  97                                        u64 ram_bytes, int compress_type,
  98                                        int type);
  99
 100 static void __endio_write_update_ordered(struct inode *inode,
 101                                          const u64 offset, const u64 bytes,
 102                                          const bool uptodate);
 103
 104 /*
 105  * Cleanup all submitted ordered extents in specified range to handle errors
 106  * from the fill_dellaloc() callback.
 107  *
 108  * NOTE: caller must ensure that when an error happens, it can not call
 109  * extent_clear_unlock_delalloc() to clear both the bits EXTENT_DO_ACCOUNTING
 110  * and EXTENT_DELALLOC simultaneously, because that causes the reserved metadata
 111  * to be released, which we want to happen only when finishing the ordered
 112  * extent (btrfs_finish_ordered_io()). Also note that the caller of the
 113  * fill_delalloc() callback already does proper cleanup for the first page of
 114  * the range, that is, it invokes the callback writepage_end_io_hook() for the
 115  * range of the first page.
 116  */
 117 static inline void btrfs_cleanup_ordered_extents(struct inode *inode,
 118                                                  const u64 offset,
 119                                                  const u64 bytes)
 120 {
 121         unsigned long index = offset >> PAGE_SHIFT;
 122         unsigned long end_index = (offset + bytes - 1) >> PAGE_SHIFT;
 123         struct page *page;
 124
 125         while (index <= end_index) {
 126                 page = find_get_page(inode->i_mapping, index);
 127                 index++;
 128                 if (!page)
 129                         continue;
 130                 ClearPagePrivate2(page);
 131                 put_page(page);
 132         }
 133         return __endio_write_update_ordered(inode, offset + PAGE_SIZE,
 134                                             bytes - PAGE_SIZE, false);
 135 }
 136
 137 static int btrfs_dirty_inode(struct inode *inode);
 138
 139 #ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
 140 void btrfs_test_inode_set_ops(struct inode *inode)
 141 {
 142         BTRFS_I(inode)->io_tree.ops = &btrfs_extent_io_ops;
 143 }
 144 #endif
 145
 146 static int btrfs_init_inode_security(struct btrfs_trans_handle *trans,
 147                                      struct inode *inode,  struct inode *dir,
 148                                      const struct qstr *qstr)
 149 {
 150         int err;
 151
 152         err = btrfs_init_acl(trans, inode, dir);
 153         if (!err)
 154                 err = btrfs_xattr_security_init(trans, inode, dir, qstr);
 155         return err;
 156 }
 157
 158 /*
 159  * this does all the hard work for inserting an inline extent into
 160  * the btree.  The caller should have done a btrfs_drop_extents so that
 161  * no overlapping inline items exist in the btree
 162  */
 163 static int insert_inline_extent(struct btrfs_trans_handle *trans,
 164                                 struct btrfs_path *path, int extent_inserted,
 165                                 struct btrfs_root *root, struct inode *inode,
 166                                 u64 start, size_t size, size_t compressed_size,
 167                                 int compress_type,
 168                                 struct page **compressed_pages)
 169 {
 170         struct extent_buffer *leaf;
 171         struct page *page = NULL;
 172         char *kaddr;
 173         unsigned long ptr;
 174         struct btrfs_file_extent_item *ei;
 175         int ret;
 176         size_t cur_size = size;
 177         unsigned long offset;
 178
 179         if (compressed_size && compressed_pages)
 180                 cur_size = compressed_size;
 181
 182         inode_add_bytes(inode, size);
 183
 184         if (!extent_inserted) {
 185                 struct btrfs_key key;
 186                 size_t datasize;
 187
 188                 key.objectid = btrfs_ino(BTRFS_I(inode));
 189                 key.offset = start;
 190                 key.type = BTRFS_EXTENT_DATA_KEY;
 191
 192                 datasize = btrfs_file_extent_calc_inline_size(cur_size);
 193                 path->leave_spinning = 1;
 194                 ret = btrfs_insert_empty_item(trans, root, path, &key,
 195                                               datasize);
 196                 if (ret)
 197                         goto fail;
 198         }
 199         leaf = path->nodes[0];
 200         ei = btrfs_item_ptr(leaf, path->slots[0],
 201                             struct btrfs_file_extent_item);
 202         btrfs_set_file_extent_generation(leaf, ei, trans->transid);
 203         btrfs_set_file_extent_type(leaf, ei, BTRFS_FILE_EXTENT_INLINE);
 204         btrfs_set_file_extent_encryption(leaf, ei, 0);
 205         btrfs_set_file_extent_other_encoding(leaf, ei, 0);
 206         btrfs_set_file_extent_ram_bytes(leaf, ei, size);
 207         ptr = btrfs_file_extent_inline_start(ei);
 208
 209         if (compress_type != BTRFS_COMPRESS_NONE) {
 210                 struct page *cpage;
 211                 int i = 0;
 212                 while (compressed_size > 0) {
 213                         cpage = compressed_pages[i];
 214                         cur_size = min_t(unsigned long, compressed_size,
 215                                        PAGE_SIZE);
 216
 217                         kaddr = kmap_atomic(cpage);
 218                         write_extent_buffer(leaf, kaddr, ptr, cur_size);
 219                         kunmap_atomic(kaddr);
 220
 221                         i++;
 222                         ptr += cur_size;
 223                         compressed_size -= cur_size;
 224                 }
 225                 btrfs_set_file_extent_compression(leaf, ei,
 226                                                   compress_type);
 227         } else {
 228                 page = find_get_page(inode->i_mapping,
 229                                      start >> PAGE_SHIFT);
 230                 btrfs_set_file_extent_compression(leaf, ei, 0);
 231                 kaddr = kmap_atomic(page);
 232                 offset = start & (PAGE_SIZE - 1);
 233                 write_extent_buffer(leaf, kaddr + offset, ptr, size);
 234                 kunmap_atomic(kaddr);
 235                 put_page(page);
 236         }
 237         btrfs_mark_buffer_dirty(leaf);
 238         btrfs_release_path(path);
 239
 240         /*
 241          * we're an inline extent, so nobody can
 242          * extend the file past i_size without locking
 243          * a page we already have locked.
 244          *
 245          * We must do any isize and inode updates
 246          * before we unlock the pages.  Otherwise we
 247          * could end up racing with unlink.
 248          */
 249         BTRFS_I(inode)->disk_i_size = inode->i_size;
 250         ret = btrfs_update_inode(trans, root, inode);
 251
 252 fail:
 253         return ret;
 254 }
 255
 256
 257 /*
 258  * conditionally insert an inline extent into the file.  This
 259  * does the checks required to make sure the data is small enough
 260  * to fit as an inline extent.
 261  */
 262 static noinline int cow_file_range_inline(struct inode *inode, u64 start,
 263                                           u64 end, size_t compressed_size,
 264                                           int compress_type,
 265                                           struct page **compressed_pages)
 266 {
 267         struct btrfs_root *root = BTRFS_I(inode)->root;
 268         struct btrfs_fs_info *fs_info = root->fs_info;
 269         struct btrfs_trans_handle *trans;
 270         u64 isize = i_size_read(inode);
 271         u64 actual_end = min(end + 1, isize);
 272         u64 inline_len = actual_end - start;
 273         u64 aligned_end = ALIGN(end, fs_info->sectorsize);
 274         u64 data_len = inline_len;
 275         int ret;
 276         struct btrfs_path *path;
 277         int extent_inserted = 0;
 278         u32 extent_item_size;
 279
 280         if (compressed_size)
 281                 data_len = compressed_size;
 282
 283         if (start > 0 ||
 284             actual_end > fs_info->sectorsize ||
 285             data_len > BTRFS_MAX_INLINE_DATA_SIZE(fs_info) ||
 286             (!compressed_size &&
 287             (actual_end & (fs_info->sectorsize - 1)) == 0) ||
 288             end + 1 < isize ||
 289             data_len > fs_info->max_inline) {
 290                 return 1;
 291         }
 292
 293         path = btrfs_alloc_path();
 294         if (!path)
 295                 return -ENOMEM;
 296
 297         trans = btrfs_join_transaction(root);
 298         if (IS_ERR(trans)) {
 299                 btrfs_free_path(path);
 300                 return PTR_ERR(trans);
 301         }
 302         trans->block_rsv = &BTRFS_I(inode)->block_rsv;
 303
 304         if (compressed_size && compressed_pages)
 305                 extent_item_size = btrfs_file_extent_calc_inline_size(
 306                    compressed_size);
 307         else
 308                 extent_item_size = btrfs_file_extent_calc_inline_size(
 309                     inline_len);
 310
 311         ret = __btrfs_drop_extents(trans, root, inode, path,
 312                                    start, aligned_end, NULL,
 313                                    1, 1, extent_item_size, &extent_inserted);
 314         if (ret) {
 315                 btrfs_abort_transaction(trans, ret);
 316                 goto out;
 317         }
 318
 319         if (isize > actual_end)
 320                 inline_len = min_t(u64, isize, actual_end);
 321         ret = insert_inline_extent(trans, path, extent_inserted,
 322                                    root, inode, start,
 323                                    inline_len, compressed_size,
 324                                    compress_type, compressed_pages);
 325         if (ret && ret != -ENOSPC) {
 326                 btrfs_abort_transaction(trans, ret);
 327                 goto out;
 328         } else if (ret == -ENOSPC) {
 329                 ret = 1;
 330                 goto out;
 331         }
 332
 333         set_bit(BTRFS_INODE_NEEDS_FULL_SYNC, &BTRFS_I(inode)->runtime_flags);
 334         btrfs_drop_extent_cache(BTRFS_I(inode), start, aligned_end - 1, 0);
 335 out:
 336         /*
 337          * Don't forget to free the reserved space, as for inlined extent
 338          * it won't count as data extent, free them directly here.
 339          * And at reserve time, it's always aligned to page size, so
 340          * just free one page here.
 341          */
 342         btrfs_qgroup_free_data(inode, NULL, 0, PAGE_SIZE);
 343         btrfs_free_path(path);
 344         btrfs_end_transaction(trans);
 345         return ret;
 346 }
 347
 348 struct async_extent {
 349         u64 start;
 350         u64 ram_size;
 351         u64 compressed_size;
 352         struct page **pages;
 353         unsigned long nr_pages;
 354         int compress_type;
 355         struct list_head list;
 356 };
 357
 358 struct async_cow {
 359         struct inode *inode;
 360         struct btrfs_root *root;
 361         struct page *locked_page;
 362         u64 start;
 363         u64 end;
 364         unsigned int write_flags;
 365         struct list_head extents;
 366         struct btrfs_work work;
 367 };
 368
 369 static noinline int add_async_extent(struct async_cow *cow,
 370                                      u64 start, u64 ram_size,
 371                                      u64 compressed_size,
 372                                      struct page **pages,
 373                                      unsigned long nr_pages,
 374                                      int compress_type)
 375 {
 376         struct async_extent *async_extent;
 377
 378         async_extent = kmalloc(sizeof(*async_extent), GFP_NOFS);
 379         BUG_ON(!async_extent); /* -ENOMEM */
 380         async_extent->start = start;
 381         async_extent->ram_size = ram_size;
 382         async_extent->compressed_size = compressed_size;
 383         async_extent->pages = pages;
 384         async_extent->nr_pages = nr_pages;
 385         async_extent->compress_type = compress_type;
 386         list_add_tail(&async_extent->list, &cow->extents);
 387         return 0;
 388 }
 389
 390 static inline int inode_need_compress(struct inode *inode, u64 start, u64 end)
 391 {
 392         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
 393
 394         /* force compress */
 395         if (btrfs_test_opt(fs_info, FORCE_COMPRESS))
 396                 return 1;
 397         /* defrag ioctl */
 398         if (BTRFS_I(inode)->defrag_compress)
 399                 return 1;
 400         /* bad compression ratios */
 401         if (BTRFS_I(inode)->flags & BTRFS_INODE_NOCOMPRESS)
 402                 return 0;
 403         if (btrfs_test_opt(fs_info, COMPRESS) ||
 404             BTRFS_I(inode)->flags & BTRFS_INODE_COMPRESS ||
 405             BTRFS_I(inode)->prop_compress)
 406                 return btrfs_compress_heuristic(inode, start, end);
 407         return 0;
 408 }
 409
 410 static inline void inode_should_defrag(struct btrfs_inode *inode,
 411                 u64 start, u64 end, u64 num_bytes, u64 small_write)
 412 {
 413         /* If this is a small write inside eof, kick off a defrag */
 414         if (num_bytes < small_write &&
 415             (start > 0 || end + 1 < inode->disk_i_size))
 416                 btrfs_add_inode_defrag(NULL, inode);
 417 }
 418
 419 /*
 420  * we create compressed extents in two phases.  The first
 421  * phase compresses a range of pages that have already been
 422  * locked (both pages and state bits are locked).
 423  *
 424  * This is done inside an ordered work queue, and the compression
 425  * is spread across many cpus.  The actual IO submission is step
 426  * two, and the ordered work queue takes care of making sure that
 427  * happens in the same order things were put onto the queue by
 428  * writepages and friends.
 429  *
 430  * If this code finds it can't get good compression, it puts an
 431  * entry onto the work queue to write the uncompressed bytes.  This
 432  * makes sure that both compressed inodes and uncompressed inodes
 433  * are written in the same order that the flusher thread sent them
 434  * down.
 435  */
 436 static noinline void compress_file_range(struct inode *inode,
 437                                         struct page *locked_page,
 438                                         u64 start, u64 end,
 439                                         struct async_cow *async_cow,
 440                                         int *num_added)
 441 {
 442         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
 443         u64 blocksize = fs_info->sectorsize;
 444         u64 actual_end;
 445         u64 isize = i_size_read(inode);
 446         int ret = 0;
 447         struct page **pages = NULL;
 448         unsigned long nr_pages;
 449         unsigned long total_compressed = 0;
 450         unsigned long total_in = 0;
 451         int i;
 452         int will_compress;
 453         int compress_type = fs_info->compress_type;
 454         int redirty = 0;
 455
 456         inode_should_defrag(BTRFS_I(inode), start, end, end - start + 1,
 457                         SZ_16K);
 458
 459         actual_end = min_t(u64, isize, end + 1);
 460 again:
 461         will_compress = 0;
 462         nr_pages = (end >> PAGE_SHIFT) - (start >> PAGE_SHIFT) + 1;
 463         BUILD_BUG_ON((BTRFS_MAX_COMPRESSED % PAGE_SIZE) != 0);
 464         nr_pages = min_t(unsigned long, nr_pages,
 465                         BTRFS_MAX_COMPRESSED / PAGE_SIZE);
 466
 467         /*
 468          * we don't want to send crud past the end of i_size through
 469          * compression, that's just a waste of CPU time.  So, if the
 470          * end of the file is before the start of our current
 471          * requested range of bytes, we bail out to the uncompressed
 472          * cleanup code that can deal with all of this.
 473          *
 474          * It isn't really the fastest way to fix things, but this is a
 475          * very uncommon corner.
 476          */
 477         if (actual_end <= start)
 478                 goto cleanup_and_bail_uncompressed;
 479
 480         total_compressed = actual_end - start;
 481
 482         /*
 483          * skip compression for a small file range(<=blocksize) that
 484          * isn't an inline extent, since it doesn't save disk space at all.
 485          */
 486         if (total_compressed <= blocksize &&
 487            (start > 0 || end + 1 < BTRFS_I(inode)->disk_i_size))
 488                 goto cleanup_and_bail_uncompressed;
 489
 490         total_compressed = min_t(unsigned long, total_compressed,
 491                         BTRFS_MAX_UNCOMPRESSED);
 492         total_in = 0;
 493         ret = 0;
 494
 495         /*
 496          * we do compression for mount -o compress and when the
 497          * inode has not been flagged as nocompress.  This flag can
 498          * change at any time if we discover bad compression ratios.
 499          */
 500         if (inode_need_compress(inode, start, end)) {
 501                 WARN_ON(pages);
 502                 pages = kcalloc(nr_pages, sizeof(struct page *), GFP_NOFS);
 503                 if (!pages) {
 504                         /* just bail out to the uncompressed code */
 505                         goto cont;
 506                 }
 507
 508                 if (BTRFS_I(inode)->defrag_compress)
 509                         compress_type = BTRFS_I(inode)->defrag_compress;
 510                 else if (BTRFS_I(inode)->prop_compress)
 511                         compress_type = BTRFS_I(inode)->prop_compress;
 512
 513                 /*
 514                  * we need to call clear_page_dirty_for_io on each
 515                  * page in the range.  Otherwise applications with the file
 516                  * mmap'd can wander in and change the page contents while
 517                  * we are compressing them.
 518                  *
 519                  * If the compression fails for any reason, we set the pages
 520                  * dirty again later on.
 521                  *
 522                  * Note that the remaining part is redirtied, the start pointer
 523                  * has moved, the end is the original one.
 524                  */
 525                 if (!redirty) {
 526                         extent_range_clear_dirty_for_io(inode, start, end);
 527                         redirty = 1;
 528                 }
 529
 530                 /* Compression level is applied here and only here */
 531                 ret = btrfs_compress_pages(
 532                         compress_type | (fs_info->compress_level << 4),
 533                                            inode->i_mapping, start,
 534                                            pages,
 535                                            &nr_pages,
 536                                            &total_in,
 537                                            &total_compressed);
 538
 539                 if (!ret) {
 540                         unsigned long offset = total_compressed &
 541                                 (PAGE_SIZE - 1);
 542                         struct page *page = pages[nr_pages - 1];
 543                         char *kaddr;
 544
 545                         /* zero the tail end of the last page, we might be
 546                          * sending it down to disk
 547                          */
 548                         if (offset) {
 549                                 kaddr = kmap_atomic(page);
 550                                 memset(kaddr + offset, 0,
 551                                        PAGE_SIZE - offset);
 552                                 kunmap_atomic(kaddr);
 553                         }
 554                         will_compress = 1;
 555                 }
 556         }
 557 cont:
 558         if (start == 0) {
 559                 /* lets try to make an inline extent */
 560                 if (ret || total_in < actual_end) {
 561                         /* we didn't compress the entire range, try
 562                          * to make an uncompressed inline extent.
 563                          */
 564                         ret = cow_file_range_inline(inode, start, end, 0,
 565                                                     BTRFS_COMPRESS_NONE, NULL);
 566                 } else {
 567                         /* try making a compressed inline extent */
 568                         ret = cow_file_range_inline(inode, start, end,
 569                                                     total_compressed,
 570                                                     compress_type, pages);
 571                 }
 572                 if (ret <= 0) {
 573                         unsigned long clear_flags = EXTENT_DELALLOC |
 574                                 EXTENT_DELALLOC_NEW | EXTENT_DEFRAG |
 575                                 EXTENT_DO_ACCOUNTING;
 576                         unsigned long page_error_op;
 577
 578                         page_error_op = ret < 0 ? PAGE_SET_ERROR : 0;
 579
 580                         /*
 581                          * inline extent creation worked or returned error,
 582                          * we don't need to create any more async work items.
 583                          * Unlock and free up our temp pages.
 584                          *
 585                          * We use DO_ACCOUNTING here because we need the
 586                          * delalloc_release_metadata to be done _after_ we drop
 587                          * our outstanding extent for clearing delalloc for this
 588                          * range.
 589                          */
 590                         extent_clear_unlock_delalloc(inode, start, end, end,
 591                                                      NULL, clear_flags,
 592                                                      PAGE_UNLOCK |
 593                                                      PAGE_CLEAR_DIRTY |
 594                                                      PAGE_SET_WRITEBACK |
 595                                                      page_error_op |
 596                                                      PAGE_END_WRITEBACK);
 597                         goto free_pages_out;
 598                 }
 599         }
 600
 601         if (will_compress) {
 602                 /*
 603                  * we aren't doing an inline extent round the compressed size
 604                  * up to a block size boundary so the allocator does sane
 605                  * things
 606                  */
 607                 total_compressed = ALIGN(total_compressed, blocksize);
 608
 609                 /*
 610                  * one last check to make sure the compression is really a
 611                  * win, compare the page count read with the blocks on disk,
 612                  * compression must free at least one sector size
 613                  */
 614                 total_in = ALIGN(total_in, PAGE_SIZE);
 615                 if (total_compressed + blocksize <= total_in) {
 616                         *num_added += 1;
 617
 618                         /*
 619                          * The async work queues will take care of doing actual
 620                          * allocation on disk for these compressed pages, and
 621                          * will submit them to the elevator.
 622                          */
 623                         add_async_extent(async_cow, start, total_in,
 624                                         total_compressed, pages, nr_pages,
 625                                         compress_type);
 626
 627                         if (start + total_in < end) {
 628                                 start += total_in;
 629                                 pages = NULL;
 630                                 cond_resched();
 631                                 goto again;
 632                         }
 633                         return;
 634                 }
 635         }
 636         if (pages) {
 637                 /*
 638                  * the compression code ran but failed to make things smaller,
 639                  * free any pages it allocated and our page pointer array
 640                  */
 641                 for (i = 0; i < nr_pages; i++) {
 642                         WARN_ON(pages[i]->mapping);
 643                         put_page(pages[i]);
 644                 }
 645                 kfree(pages);
 646                 pages = NULL;
 647                 total_compressed = 0;
 648                 nr_pages = 0;
 649
 650                 /* flag the file so we don't compress in the future */
 651                 if (!btrfs_test_opt(fs_info, FORCE_COMPRESS) &&
 652                     !(BTRFS_I(inode)->prop_compress)) {
 653                         BTRFS_I(inode)->flags |= BTRFS_INODE_NOCOMPRESS;
 654                 }
 655         }
 656 cleanup_and_bail_uncompressed:
 657         /*
 658          * No compression, but we still need to write the pages in the file
 659          * we've been given so far.  redirty the locked page if it corresponds
 660          * to our extent and set things up for the async work queue to run
 661          * cow_file_range to do the normal delalloc dance.
 662          */
 663         if (page_offset(locked_page) >= start &&
 664             page_offset(locked_page) <= end)
 665                 __set_page_dirty_nobuffers(locked_page);
 666                 /* unlocked later on in the async handlers */
 667
 668         if (redirty)
 669                 extent_range_redirty_for_io(inode, start, end);
 670         add_async_extent(async_cow, start, end - start + 1, 0, NULL, 0,
 671                          BTRFS_COMPRESS_NONE);
 672         *num_added += 1;
 673
 674         return;
 675
 676 free_pages_out:
 677         for (i = 0; i < nr_pages; i++) {
 678                 WARN_ON(pages[i]->mapping);
 679                 put_page(pages[i]);
 680         }
 681         kfree(pages);
 682 }
 683
 684 static void free_async_extent_pages(struct async_extent *async_extent)
 685 {
 686         int i;
 687
 688         if (!async_extent->pages)
 689                 return;
 690
 691         for (i = 0; i < async_extent->nr_pages; i++) {
 692                 WARN_ON(async_extent->pages[i]->mapping);
 693                 put_page(async_extent->pages[i]);
 694         }
 695         kfree(async_extent->pages);
 696         async_extent->nr_pages = 0;
 697         async_extent->pages = NULL;
 698 }
 699
 700 /*
 701  * phase two of compressed writeback.  This is the ordered portion
 702  * of the code, which only gets called in the order the work was
 703  * queued.  We walk all the async extents created by compress_file_range
 704  * and send them down to the disk.
 705  */
 706 static noinline void submit_compressed_extents(struct inode *inode,
 707                                               struct async_cow *async_cow)
 708 {
 709         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
 710         struct async_extent *async_extent;
 711         u64 alloc_hint = 0;
 712         struct btrfs_key ins;
 713         struct extent_map *em;
 714         struct btrfs_root *root = BTRFS_I(inode)->root;
 715         struct extent_io_tree *io_tree;
 716         int ret = 0;
 717
 718 again:
 719         while (!list_empty(&async_cow->extents)) {
 720                 async_extent = list_entry(async_cow->extents.next,
 721                                           struct async_extent, list);
 722                 list_del(&async_extent->list);
 723
 724                 io_tree = &BTRFS_I(inode)->io_tree;
 725
 726 retry:
 727                 /* did the compression code fall back to uncompressed IO? */
 728                 if (!async_extent->pages) {
 729                         int page_started = 0;
 730                         unsigned long nr_written = 0;
 731
 732                         lock_extent(io_tree, async_extent->start,
 733                                          async_extent->start +
 734                                          async_extent->ram_size - 1);
 735
 736                         /* allocate blocks */
 737                         ret = cow_file_range(inode, async_cow->locked_page,
 738                                              async_extent->start,
 739                                              async_extent->start +
 740                                              async_extent->ram_size - 1,
 741                                              async_extent->start +
 742                                              async_extent->ram_size - 1,
 743                                              &page_started, &nr_written, 0,
 744                                              NULL);
 745
 746                         /* JDM XXX */
 747
 748                         /*
 749                          * if page_started, cow_file_range inserted an
 750                          * inline extent and took care of all the unlocking
 751                          * and IO for us.  Otherwise, we need to submit
 752                          * all those pages down to the drive.
 753                          */
 754                         if (!page_started && !ret)
 755                                 extent_write_locked_range(inode,
 756                                                   async_extent->start,
 757                                                   async_extent->start +
 758                                                   async_extent->ram_size - 1,
 759                                                   WB_SYNC_ALL);
 760                         else if (ret)
 761                                 unlock_page(async_cow->locked_page);
 762                         kfree(async_extent);
 763                         cond_resched();
 764                         continue;
 765                 }
 766
 767                 lock_extent(io_tree, async_extent->start,
 768                             async_extent->start + async_extent->ram_size - 1);
 769
 770                 ret = btrfs_reserve_extent(root, async_extent->ram_size,
 771                                            async_extent->compressed_size,
 772                                            async_extent->compressed_size,
 773                                            0, alloc_hint, &ins, 1, 1);
 774                 if (ret) {
 775                         free_async_extent_pages(async_extent);
 776
 777                         if (ret == -ENOSPC) {
 778                                 unlock_extent(io_tree, async_extent->start,
 779                                               async_extent->start +
 780                                               async_extent->ram_size - 1);
 781
 782                                 /*
 783                                  * we need to redirty the pages if we decide to
 784                                  * fallback to uncompressed IO, otherwise we
 785                                  * will not submit these pages down to lower
 786                                  * layers.
 787                                  */
 788                                 extent_range_redirty_for_io(inode,
 789                                                 async_extent->start,
 790                                                 async_extent->start +
 791                                                 async_extent->ram_size - 1);
 792
 793                                 goto retry;
 794                         }
 795                         goto out_free;
 796                 }
 797                 /*
 798                  * here we're doing allocation and writeback of the
 799                  * compressed pages
 800                  */
 801                 em = create_io_em(inode, async_extent->start,
 802                                   async_extent->ram_size, /* len */
 803                                   async_extent->start, /* orig_start */
 804                                   ins.objectid, /* block_start */
 805                                   ins.offset, /* block_len */
 806                                   ins.offset, /* orig_block_len */
 807                                   async_extent->ram_size, /* ram_bytes */
 808                                   async_extent->compress_type,
 809                                   BTRFS_ORDERED_COMPRESSED);
 810                 if (IS_ERR(em))
 811                         /* ret value is not necessary due to void function */
 812                         goto out_free_reserve;
 813                 free_extent_map(em);
 814
 815                 ret = btrfs_add_ordered_extent_compress(inode,
 816                                                 async_extent->start,
 817                                                 ins.objectid,
 818                                                 async_extent->ram_size,
 819                                                 ins.offset,
 820                                                 BTRFS_ORDERED_COMPRESSED,
 821                                                 async_extent->compress_type);
 822                 if (ret) {
 823                         btrfs_drop_extent_cache(BTRFS_I(inode),
 824                                                 async_extent->start,
 825                                                 async_extent->start +
 826                                                 async_extent->ram_size - 1, 0);
 827                         goto out_free_reserve;
 828                 }
 829                 btrfs_dec_block_group_reservations(fs_info, ins.objectid);
 830
 831                 /*
 832                  * clear dirty, set writeback and unlock the pages.
 833                  */
 834                 extent_clear_unlock_delalloc(inode, async_extent->start,
 835                                 async_extent->start +
 836                                 async_extent->ram_size - 1,
 837                                 async_extent->start +
 838                                 async_extent->ram_size - 1,
 839                                 NULL, EXTENT_LOCKED | EXTENT_DELALLOC,
 840                                 PAGE_UNLOCK | PAGE_CLEAR_DIRTY |
 841                                 PAGE_SET_WRITEBACK);
 842                 if (btrfs_submit_compressed_write(inode,
 843                                     async_extent->start,
 844                                     async_extent->ram_size,
 845                                     ins.objectid,
 846                                     ins.offset, async_extent->pages,
 847                                     async_extent->nr_pages,
 848                                     async_cow->write_flags)) {
 849                         struct extent_io_tree *tree = &BTRFS_I(inode)->io_tree;
 850                         struct page *p = async_extent->pages[0];
 851                         const u64 start = async_extent->start;
 852                         const u64 end = start + async_extent->ram_size - 1;
 853
 854                         p->mapping = inode->i_mapping;
 855                         tree->ops->writepage_end_io_hook(p, start, end,
 856                                                          NULL, 0);
 857                         p->mapping = NULL;
 858                         extent_clear_unlock_delalloc(inode, start, end, end,
 859                                                      NULL, 0,
 860                                                      PAGE_END_WRITEBACK |
 861                                                      PAGE_SET_ERROR);
 862                         free_async_extent_pages(async_extent);
 863                 }
 864                 alloc_hint = ins.objectid + ins.offset;
 865                 kfree(async_extent);
 866                 cond_resched();
 867         }
 868         return;
 869 out_free_reserve:
 870         btrfs_dec_block_group_reservations(fs_info, ins.objectid);
 871         btrfs_free_reserved_extent(fs_info, ins.objectid, ins.offset, 1);
 872 out_free:
 873         extent_clear_unlock_delalloc(inode, async_extent->start,
 874                                      async_extent->start +
 875                                      async_extent->ram_size - 1,
 876                                      async_extent->start +
 877                                      async_extent->ram_size - 1,
 878                                      NULL, EXTENT_LOCKED | EXTENT_DELALLOC |
 879                                      EXTENT_DELALLOC_NEW |
 880                                      EXTENT_DEFRAG | EXTENT_DO_ACCOUNTING,
 881                                      PAGE_UNLOCK | PAGE_CLEAR_DIRTY |
 882                                      PAGE_SET_WRITEBACK | PAGE_END_WRITEBACK |
 883                                      PAGE_SET_ERROR);
 884         free_async_extent_pages(async_extent);
 885         kfree(async_extent);
 886         goto again;
 887 }
 888
 889 static u64 get_extent_allocation_hint(struct inode *inode, u64 start,
 890                                       u64 num_bytes)
 891 {
 892         struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
 893         struct extent_map *em;
 894         u64 alloc_hint = 0;
 895
 896         read_lock(&em_tree->lock);
 897         em = search_extent_mapping(em_tree, start, num_bytes);
 898         if (em) {
 899                 /*
 900                  * if block start isn't an actual block number then find the
 901                  * first block in this inode and use that as a hint.  If that
 902                  * block is also bogus then just don't worry about it.
 903                  */
 904                 if (em->block_start >= EXTENT_MAP_LAST_BYTE) {
 905                         free_extent_map(em);
 906                         em = search_extent_mapping(em_tree, 0, 0);
 907                         if (em && em->block_start < EXTENT_MAP_LAST_BYTE)
 908                                 alloc_hint = em->block_start;
 909                         if (em)
 910                                 free_extent_map(em);
 911                 } else {
 912                         alloc_hint = em->block_start;
 913                         free_extent_map(em);
 914                 }
 915         }
 916         read_unlock(&em_tree->lock);
 917
 918         return alloc_hint;
 919 }
 920
 921 /*
 922  * when extent_io.c finds a delayed allocation range in the file,
 923  * the call backs end up in this code.  The basic idea is to
 924  * allocate extents on disk for the range, and create ordered data structs
 925  * in ram to track those extents.
 926  *
 927  * locked_page is the page that writepage had locked already.  We use
 928  * it to make sure we don't do extra locks or unlocks.
 929  *
 930  * *page_started is set to one if we unlock locked_page and do everything
 931  * required to start IO on it.  It may be clean and already done with
 932  * IO when we return.
 933  */
 934 static noinline int cow_file_range(struct inode *inode,
 935                                    struct page *locked_page,
 936                                    u64 start, u64 end, u64 delalloc_end,
 937                                    int *page_started, unsigned long *nr_written,
 938                                    int unlock, struct btrfs_dedupe_hash *hash)
 939 {
 940         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
 941         struct btrfs_root *root = BTRFS_I(inode)->root;
 942         u64 alloc_hint = 0;
 943         u64 num_bytes;
 944         unsigned long ram_size;
 945         u64 cur_alloc_size = 0;
 946         u64 blocksize = fs_info->sectorsize;
 947         struct btrfs_key ins;
 948         struct extent_map *em;
 949         unsigned clear_bits;
 950         unsigned long page_ops;
 951         bool extent_reserved = false;
 952         int ret = 0;
 953
 954         if (btrfs_is_free_space_inode(BTRFS_I(inode))) {
 955                 WARN_ON_ONCE(1);
 956                 ret = -EINVAL;
 957                 goto out_unlock;
 958         }
 959
 960         num_bytes = ALIGN(end - start + 1, blocksize);
 961         num_bytes = max(blocksize,  num_bytes);
 962         ASSERT(num_bytes <= btrfs_super_total_bytes(fs_info->super_copy));
 963
 964         inode_should_defrag(BTRFS_I(inode), start, end, num_bytes, SZ_64K);
 965
 966         if (start == 0) {
 967                 /* lets try to make an inline extent */
 968                 ret = cow_file_range_inline(inode, start, end, 0,
 969                                             BTRFS_COMPRESS_NONE, NULL);
 970                 if (ret == 0) {
 971                         /*
 972                          * We use DO_ACCOUNTING here because we need the
 973                          * delalloc_release_metadata to be run _after_ we drop
 974                          * our outstanding extent for clearing delalloc for this
 975                          * range.
 976                          */
 977                         extent_clear_unlock_delalloc(inode, start, end,
 978                                      delalloc_end, NULL,
 979                                      EXTENT_LOCKED | EXTENT_DELALLOC |
 980                                      EXTENT_DELALLOC_NEW | EXTENT_DEFRAG |
 981                                      EXTENT_DO_ACCOUNTING, PAGE_UNLOCK |
 982                                      PAGE_CLEAR_DIRTY | PAGE_SET_WRITEBACK |
 983                                      PAGE_END_WRITEBACK);
 984                         *nr_written = *nr_written +
 985                              (end - start + PAGE_SIZE) / PAGE_SIZE;
 986                         *page_started = 1;
 987                         goto out;
 988                 } else if (ret < 0) {
 989                         goto out_unlock;
 990                 }
 991         }
 992
 993         alloc_hint = get_extent_allocation_hint(inode, start, num_bytes);
 994         btrfs_drop_extent_cache(BTRFS_I(inode), start,
 995                         start + num_bytes - 1, 0);
 996
 997         while (num_bytes > 0) {
 998                 cur_alloc_size = num_bytes;
 999                 ret = btrfs_reserve_extent(root, cur_alloc_size, cur_alloc_size,
1000                                            fs_info->sectorsize, 0, alloc_hint,
1001                                            &ins, 1, 1);
1002                 if (ret < 0)
1003                         goto out_unlock;
1004                 cur_alloc_size = ins.offset;
1005                 extent_reserved = true;
1006
1007                 ram_size = ins.offset;
1008                 em = create_io_em(inode, start, ins.offset, /* len */
1009                                   start, /* orig_start */
1010                                   ins.objectid, /* block_start */
1011                                   ins.offset, /* block_len */
1012                                   ins.offset, /* orig_block_len */
1013                                   ram_size, /* ram_bytes */
1014                                   BTRFS_COMPRESS_NONE, /* compress_type */
1015                                   BTRFS_ORDERED_REGULAR /* type */);
1016                 if (IS_ERR(em)) {
1017                         ret = PTR_ERR(em);
1018                         goto out_reserve;
1019                 }
1020                 free_extent_map(em);
1021
1022                 ret = btrfs_add_ordered_extent(inode, start, ins.objectid,
1023                                                ram_size, cur_alloc_size, 0);
1024                 if (ret)
1025                         goto out_drop_extent_cache;
1026
1027                 if (root->root_key.objectid ==
1028                     BTRFS_DATA_RELOC_TREE_OBJECTID) {
1029                         ret = btrfs_reloc_clone_csums(inode, start,
1030                                                       cur_alloc_size);
1031                         /*
1032                          * Only drop cache here, and process as normal.
1033                          *
1034                          * We must not allow extent_clear_unlock_delalloc()
1035                          * at out_unlock label to free meta of this ordered
1036                          * extent, as its meta should be freed by
1037                          * btrfs_finish_ordered_io().
1038                          *
1039                          * So we must continue until @start is increased to
1040                          * skip current ordered extent.
1041                          */
1042                         if (ret)
1043                                 btrfs_drop_extent_cache(BTRFS_I(inode), start,
1044                                                 start + ram_size - 1, 0);
1045                 }
1046
1047                 btrfs_dec_block_group_reservations(fs_info, ins.objectid);
1048
1049                 /* we're not doing compressed IO, don't unlock the first
1050                  * page (which the caller expects to stay locked), don't
1051                  * clear any dirty bits and don't set any writeback bits
1052                  *
1053                  * Do set the Private2 bit so we know this page was properly
1054                  * setup for writepage
1055                  */
1056                 page_ops = unlock ? PAGE_UNLOCK : 0;
1057                 page_ops |= PAGE_SET_PRIVATE2;
1058
1059                 extent_clear_unlock_delalloc(inode, start,
1060                                              start + ram_size - 1,
1061                                              delalloc_end, locked_page,
1062                                              EXTENT_LOCKED | EXTENT_DELALLOC,
1063                                              page_ops);
1064                 if (num_bytes < cur_alloc_size)
1065                         num_bytes = 0;
1066                 else
1067                         num_bytes -= cur_alloc_size;
1068                 alloc_hint = ins.objectid + ins.offset;
1069                 start += cur_alloc_size;
1070                 extent_reserved = false;
1071
1072                 /*
1073                  * btrfs_reloc_clone_csums() error, since start is increased
1074                  * extent_clear_unlock_delalloc() at out_unlock label won't
1075                  * free metadata of current ordered extent, we're OK to exit.
1076                  */
1077                 if (ret)
1078                         goto out_unlock;
1079         }
1080 out:
1081         return ret;
1082
1083 out_drop_extent_cache:
1084         btrfs_drop_extent_cache(BTRFS_I(inode), start, start + ram_size - 1, 0);
1085 out_reserve:
1086         btrfs_dec_block_group_reservations(fs_info, ins.objectid);
1087         btrfs_free_reserved_extent(fs_info, ins.objectid, ins.offset, 1);
1088 out_unlock:
1089         clear_bits = EXTENT_LOCKED | EXTENT_DELALLOC | EXTENT_DELALLOC_NEW |
1090                 EXTENT_DEFRAG | EXTENT_CLEAR_META_RESV;
1091         page_ops = PAGE_UNLOCK | PAGE_CLEAR_DIRTY | PAGE_SET_WRITEBACK |
1092                 PAGE_END_WRITEBACK;
1093         /*
1094          * If we reserved an extent for our delalloc range (or a subrange) and
1095          * failed to create the respective ordered extent, then it means that
1096          * when we reserved the extent we decremented the extent's size from
1097          * the data space_info's bytes_may_use counter and incremented the
1098          * space_info's bytes_reserved counter by the same amount. We must make
1099          * sure extent_clear_unlock_delalloc() does not try to decrement again
1100          * the data space_info's bytes_may_use counter, therefore we do not pass
1101          * it the flag EXTENT_CLEAR_DATA_RESV.
1102          */
1103         if (extent_reserved) {
1104                 extent_clear_unlock_delalloc(inode, start,
1105                                              start + cur_alloc_size,
1106                                              start + cur_alloc_size,
1107                                              locked_page,
1108                                              clear_bits,
1109                                              page_ops);
1110                 start += cur_alloc_size;
1111                 if (start >= end)
1112                         goto out;
1113         }
1114         extent_clear_unlock_delalloc(inode, start, end, delalloc_end,
1115                                      locked_page,
1116                                      clear_bits | EXTENT_CLEAR_DATA_RESV,
1117                                      page_ops);
1118         goto out;
1119 }
1120
1121 /*
1122  * work queue call back to started compression on a file and pages
1123  */
1124 static noinline void async_cow_start(struct btrfs_work *work)
1125 {
1126         struct async_cow *async_cow;
1127         int num_added = 0;
1128         async_cow = container_of(work, struct async_cow, work);
1129
1130         compress_file_range(async_cow->inode, async_cow->locked_page,
1131                             async_cow->start, async_cow->end, async_cow,
1132                             &num_added);
1133         if (num_added == 0) {
1134                 btrfs_add_delayed_iput(async_cow->inode);
1135                 async_cow->inode = NULL;
1136         }
1137 }
1138
1139 /*
1140  * work queue call back to submit previously compressed pages
1141  */
1142 static noinline void async_cow_submit(struct btrfs_work *work)
1143 {
1144         struct btrfs_fs_info *fs_info;
1145         struct async_cow *async_cow;
1146         struct btrfs_root *root;
1147         unsigned long nr_pages;
1148
1149         async_cow = container_of(work, struct async_cow, work);
1150
1151         root = async_cow->root;
1152         fs_info = root->fs_info;
1153         nr_pages = (async_cow->end - async_cow->start + PAGE_SIZE) >>
1154                 PAGE_SHIFT;
1155
1156         /* atomic_sub_return implies a barrier */
1157         if (atomic_sub_return(nr_pages, &fs_info->async_delalloc_pages) <
1158             5 * SZ_1M)
1159                 cond_wake_up_nomb(&fs_info->async_submit_wait);
1160
1161         if (async_cow->inode)
1162                 submit_compressed_extents(async_cow->inode, async_cow);
1163 }
1164
1165 static noinline void async_cow_free(struct btrfs_work *work)
1166 {
1167         struct async_cow *async_cow;
1168         async_cow = container_of(work, struct async_cow, work);
1169         if (async_cow->inode)
1170                 btrfs_add_delayed_iput(async_cow->inode);
1171         kfree(async_cow);
1172 }
1173
1174 static int cow_file_range_async(struct inode *inode, struct page *locked_page,
1175                                 u64 start, u64 end, int *page_started,
1176                                 unsigned long *nr_written,
1177                                 unsigned int write_flags)
1178 {
1179         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
1180         struct async_cow *async_cow;
1181         struct btrfs_root *root = BTRFS_I(inode)->root;
1182         unsigned long nr_pages;
1183         u64 cur_end;
1184
1185         clear_extent_bit(&BTRFS_I(inode)->io_tree, start, end, EXTENT_LOCKED,
1186                          1, 0, NULL);
1187         while (start < end) {
1188                 async_cow = kmalloc(sizeof(*async_cow), GFP_NOFS);
1189                 BUG_ON(!async_cow); /* -ENOMEM */
1190                 async_cow->inode = igrab(inode);
1191                 async_cow->root = root;
1192                 async_cow->locked_page = locked_page;
1193                 async_cow->start = start;
1194                 async_cow->write_flags = write_flags;
1195
1196                 if (BTRFS_I(inode)->flags & BTRFS_INODE_NOCOMPRESS &&
1197                     !btrfs_test_opt(fs_info, FORCE_COMPRESS))
1198                         cur_end = end;
1199                 else
1200                         cur_end = min(end, start + SZ_512K - 1);
1201
1202                 async_cow->end = cur_end;
1203                 INIT_LIST_HEAD(&async_cow->extents);
1204
1205                 btrfs_init_work(&async_cow->work,
1206                                 btrfs_delalloc_helper,
1207                                 async_cow_start, async_cow_submit,
1208                                 async_cow_free);
1209
1210                 nr_pages = (cur_end - start + PAGE_SIZE) >>
1211                         PAGE_SHIFT;
1212                 atomic_add(nr_pages, &fs_info->async_delalloc_pages);
1213
1214                 btrfs_queue_work(fs_info->delalloc_workers, &async_cow->work);
1215
1216                 *nr_written += nr_pages;
1217                 start = cur_end + 1;
1218         }
1219         *page_started = 1;
1220         return 0;
1221 }
1222
1223 static noinline int csum_exist_in_range(struct btrfs_fs_info *fs_info,
1224                                         u64 bytenr, u64 num_bytes)
1225 {
1226         int ret;
1227         struct btrfs_ordered_sum *sums;
1228         LIST_HEAD(list);
1229
1230         ret = btrfs_lookup_csums_range(fs_info->csum_root, bytenr,
1231                                        bytenr + num_bytes - 1, &list, 0);
1232         if (ret == 0 && list_empty(&list))
1233                 return 0;
1234
1235         while (!list_empty(&list)) {
1236                 sums = list_entry(list.next, struct btrfs_ordered_sum, list);
1237                 list_del(&sums->list);
1238                 kfree(sums);
1239         }
1240         if (ret < 0)
1241                 return ret;
1242         return 1;
1243 }
1244
1245 /*
1246  * when nowcow writeback call back.  This checks for snapshots or COW copies
1247  * of the extents that exist in the file, and COWs the file as required.
1248  *
1249  * If no cow copies or snapshots exist, we write directly to the existing
1250  * blocks on disk
1251  */
1252 static noinline int run_delalloc_nocow(struct inode *inode,
1253                                        struct page *locked_page,
1254                               u64 start, u64 end, int *page_started, int force,
1255                               unsigned long *nr_written)
1256 {
1257         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
1258         struct btrfs_root *root = BTRFS_I(inode)->root;
1259         struct extent_buffer *leaf;
1260         struct btrfs_path *path;
1261         struct btrfs_file_extent_item *fi;
1262         struct btrfs_key found_key;
1263         struct extent_map *em;
1264         u64 cow_start;
1265         u64 cur_offset;
1266         u64 extent_end;
1267         u64 extent_offset;
1268         u64 disk_bytenr;
1269         u64 num_bytes;
1270         u64 disk_num_bytes;
1271         u64 ram_bytes;
1272         int extent_type;
1273         int ret;
1274         int type;
1275         int nocow;
1276         int check_prev = 1;
1277         bool nolock;
1278         u64 ino = btrfs_ino(BTRFS_I(inode));
1279
1280         path = btrfs_alloc_path();
1281         if (!path) {
1282                 extent_clear_unlock_delalloc(inode, start, end, end,
1283                                              locked_page,
1284                                              EXTENT_LOCKED | EXTENT_DELALLOC |
1285                                              EXTENT_DO_ACCOUNTING |
1286                                              EXTENT_DEFRAG, PAGE_UNLOCK |
1287                                              PAGE_CLEAR_DIRTY |
1288                                              PAGE_SET_WRITEBACK |
1289                                              PAGE_END_WRITEBACK);
1290                 return -ENOMEM;
1291         }
1292
1293         nolock = btrfs_is_free_space_inode(BTRFS_I(inode));
1294
1295         cow_start = (u64)-1;
1296         cur_offset = start;
1297         while (1) {
1298                 ret = btrfs_lookup_file_extent(NULL, root, path, ino,
1299                                                cur_offset, 0);
1300                 if (ret < 0)
1301                         goto error;
1302                 if (ret > 0 && path->slots[0] > 0 && check_prev) {
1303                         leaf = path->nodes[0];
1304                         btrfs_item_key_to_cpu(leaf, &found_key,
1305                                               path->slots[0] - 1);
1306                         if (found_key.objectid == ino &&
1307                             found_key.type == BTRFS_EXTENT_DATA_KEY)
1308                                 path->slots[0]--;
1309                 }
1310                 check_prev = 0;
1311 next_slot:
1312                 leaf = path->nodes[0];
1313                 if (path->slots[0] >= btrfs_header_nritems(leaf)) {
1314                         ret = btrfs_next_leaf(root, path);
1315                         if (ret < 0) {
1316                                 if (cow_start != (u64)-1)
1317                                         cur_offset = cow_start;
1318                                 goto error;
1319                         }
1320                         if (ret > 0)
1321                                 break;
1322                         leaf = path->nodes[0];
1323                 }
1324
1325                 nocow = 0;
1326                 disk_bytenr = 0;
1327                 num_bytes = 0;
1328                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
1329
1330                 if (found_key.objectid > ino)
1331                         break;
1332                 if (WARN_ON_ONCE(found_key.objectid < ino) ||
1333                     found_key.type < BTRFS_EXTENT_DATA_KEY) {
1334                         path->slots[0]++;
1335                         goto next_slot;
1336                 }
1337                 if (found_key.type > BTRFS_EXTENT_DATA_KEY ||
1338                     found_key.offset > end)
1339                         break;
1340
1341                 if (found_key.offset > cur_offset) {
1342                         extent_end = found_key.offset;
1343                         extent_type = 0;
1344                         goto out_check;
1345                 }
1346
1347                 fi = btrfs_item_ptr(leaf, path->slots[0],
1348                                     struct btrfs_file_extent_item);
1349                 extent_type = btrfs_file_extent_type(leaf, fi);
1350
1351                 ram_bytes = btrfs_file_extent_ram_bytes(leaf, fi);
1352                 if (extent_type == BTRFS_FILE_EXTENT_REG ||
1353                     extent_type == BTRFS_FILE_EXTENT_PREALLOC) {
1354                         disk_bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
1355                         extent_offset = btrfs_file_extent_offset(leaf, fi);
1356                         extent_end = found_key.offset +
1357                                 btrfs_file_extent_num_bytes(leaf, fi);
1358                         disk_num_bytes =
1359                                 btrfs_file_extent_disk_num_bytes(leaf, fi);
1360                         if (extent_end <= start) {
1361                                 path->slots[0]++;
1362                                 goto next_slot;
1363                         }
1364                         if (disk_bytenr == 0)
1365                                 goto out_check;
1366                         if (btrfs_file_extent_compression(leaf, fi) ||
1367                             btrfs_file_extent_encryption(leaf, fi) ||
1368                             btrfs_file_extent_other_encoding(leaf, fi))
1369                                 goto out_check;
1370                         /*
1371                          * Do the same check as in btrfs_cross_ref_exist but
1372                          * without the unnecessary search.
1373                          */
1374                         if (btrfs_file_extent_generation(leaf, fi) <=
1375                             btrfs_root_last_snapshot(&root->root_item))
1376                                 goto out_check;
1377                         if (extent_type == BTRFS_FILE_EXTENT_REG && !force)
1378                                 goto out_check;
1379                         if (btrfs_extent_readonly(fs_info, disk_bytenr))
1380                                 goto out_check;
1381                         ret = btrfs_cross_ref_exist(root, ino,
1382                                                     found_key.offset -
1383                                                     extent_offset, disk_bytenr);
1384                         if (ret) {
1385                                 /*
1386                                  * ret could be -EIO if the above fails to read
1387                                  * metadata.
1388                                  */
1389                                 if (ret < 0) {
1390                                         if (cow_start != (u64)-1)
1391                                                 cur_offset = cow_start;
1392                                         goto error;
1393                                 }
1394
1395                                 WARN_ON_ONCE(nolock);
1396                                 goto out_check;
1397                         }
1398                         disk_bytenr += extent_offset;
1399                         disk_bytenr += cur_offset - found_key.offset;
1400                         num_bytes = min(end + 1, extent_end) - cur_offset;
1401                         /*
1402                          * if there are pending snapshots for this root,
1403                          * we fall into common COW way.
1404                          */
1405                         if (!nolock && atomic_read(&root->snapshot_force_cow))
1406                                 goto out_check;
1407                         /*
1408                          * force cow if csum exists in the range.
1409                          * this ensure that csum for a given extent are
1410                          * either valid or do not exist.
1411                          */
1412                         ret = csum_exist_in_range(fs_info, disk_bytenr,
1413                                                   num_bytes);
1414                         if (ret) {
1415                                 /*
1416                                  * ret could be -EIO if the above fails to read
1417                                  * metadata.
1418                                  */
1419                                 if (ret < 0) {
1420                                         if (cow_start != (u64)-1)
1421                                                 cur_offset = cow_start;
1422                                         goto error;
1423                                 }
1424                                 WARN_ON_ONCE(nolock);
1425                                 goto out_check;
1426                         }
1427                         if (!btrfs_inc_nocow_writers(fs_info, disk_bytenr))
1428                                 goto out_check;
1429                         nocow = 1;
1430                 } else if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
1431                         extent_end = found_key.offset +
1432                                 btrfs_file_extent_ram_bytes(leaf, fi);
1433                         extent_end = ALIGN(extent_end,
1434                                            fs_info->sectorsize);
1435                 } else {
1436                         BUG_ON(1);
1437                 }
1438 out_check:
1439                 if (extent_end <= start) {
1440                         path->slots[0]++;
1441                         if (nocow)
1442                                 btrfs_dec_nocow_writers(fs_info, disk_bytenr);
1443                         goto next_slot;
1444                 }
1445                 if (!nocow) {
1446                         if (cow_start == (u64)-1)
1447                                 cow_start = cur_offset;
1448                         cur_offset = extent_end;
1449                         if (cur_offset > end)
1450                                 break;
1451                         path->slots[0]++;
1452                         goto next_slot;
1453                 }
1454
1455                 btrfs_release_path(path);
1456                 if (cow_start != (u64)-1) {
1457                         ret = cow_file_range(inode, locked_page,
1458                                              cow_start, found_key.offset - 1,
1459                                              end, page_started, nr_written, 1,
1460                                              NULL);
1461                         if (ret) {
1462                                 if (nocow)
1463                                         btrfs_dec_nocow_writers(fs_info,
1464                                                                 disk_bytenr);
1465                                 goto error;
1466                         }
1467                         cow_start = (u64)-1;
1468                 }
1469
1470                 if (extent_type == BTRFS_FILE_EXTENT_PREALLOC) {
1471                         u64 orig_start = found_key.offset - extent_offset;
1472
1473                         em = create_io_em(inode, cur_offset, num_bytes,
1474                                           orig_start,
1475                                           disk_bytenr, /* block_start */
1476                                           num_bytes, /* block_len */
1477                                           disk_num_bytes, /* orig_block_len */
1478                                           ram_bytes, BTRFS_COMPRESS_NONE,
1479                                           BTRFS_ORDERED_PREALLOC);
1480                         if (IS_ERR(em)) {
1481                                 if (nocow)
1482                                         btrfs_dec_nocow_writers(fs_info,
1483                                                                 disk_bytenr);
1484                                 ret = PTR_ERR(em);
1485                                 goto error;
1486                         }
1487                         free_extent_map(em);
1488                 }
1489
1490                 if (extent_type == BTRFS_FILE_EXTENT_PREALLOC) {
1491                         type = BTRFS_ORDERED_PREALLOC;
1492                 } else {
1493                         type = BTRFS_ORDERED_NOCOW;
1494                 }
1495
1496                 ret = btrfs_add_ordered_extent(inode, cur_offset, disk_bytenr,
1497                                                num_bytes, num_bytes, type);
1498                 if (nocow)
1499                         btrfs_dec_nocow_writers(fs_info, disk_bytenr);
1500                 BUG_ON(ret); /* -ENOMEM */
1501
1502                 if (root->root_key.objectid ==
1503                     BTRFS_DATA_RELOC_TREE_OBJECTID)
1504                         /*
1505                          * Error handled later, as we must prevent
1506                          * extent_clear_unlock_delalloc() in error handler
1507                          * from freeing metadata of created ordered extent.
1508                          */
1509                         ret = btrfs_reloc_clone_csums(inode, cur_offset,
1510                                                       num_bytes);
1511
1512                 extent_clear_unlock_delalloc(inode, cur_offset,
1513                                              cur_offset + num_bytes - 1, end,
1514                                              locked_page, EXTENT_LOCKED |
1515                                              EXTENT_DELALLOC |
1516                                              EXTENT_CLEAR_DATA_RESV,
1517                                              PAGE_UNLOCK | PAGE_SET_PRIVATE2);
1518
1519                 cur_offset = extent_end;
1520
1521                 /*
1522                  * btrfs_reloc_clone_csums() error, now we're OK to call error
1523                  * handler, as metadata for created ordered extent will only
1524                  * be freed by btrfs_finish_ordered_io().
1525                  */
1526                 if (ret)
1527                         goto error;
1528                 if (cur_offset > end)
1529                         break;
1530         }
1531         btrfs_release_path(path);
1532
1533         if (cur_offset <= end && cow_start == (u64)-1) {
1534                 cow_start = cur_offset;
1535                 cur_offset = end;
1536         }
1537
1538         if (cow_start != (u64)-1) {
1539                 ret = cow_file_range(inode, locked_page, cow_start, end, end,
1540                                      page_started, nr_written, 1, NULL);
1541                 if (ret)
1542                         goto error;
1543         }
1544
1545 error:
1546         if (ret && cur_offset < end)
1547                 extent_clear_unlock_delalloc(inode, cur_offset, end, end,
1548                                              locked_page, EXTENT_LOCKED |
1549                                              EXTENT_DELALLOC | EXTENT_DEFRAG |
1550                                              EXTENT_DO_ACCOUNTING, PAGE_UNLOCK |
1551                                              PAGE_CLEAR_DIRTY |
1552                                              PAGE_SET_WRITEBACK |
1553                                              PAGE_END_WRITEBACK);
1554         btrfs_free_path(path);
1555         return ret;
1556 }
1557
1558 static inline int need_force_cow(struct inode *inode, u64 start, u64 end)
1559 {
1560
1561         if (!(BTRFS_I(inode)->flags & BTRFS_INODE_NODATACOW) &&
1562             !(BTRFS_I(inode)->flags & BTRFS_INODE_PREALLOC))
1563                 return 0;
1564
1565         /*
1566          * @defrag_bytes is a hint value, no spinlock held here,
1567          * if is not zero, it means the file is defragging.
1568          * Force cow if given extent needs to be defragged.
1569          */
1570         if (BTRFS_I(inode)->defrag_bytes &&
1571             test_range_bit(&BTRFS_I(inode)->io_tree, start, end,
1572                            EXTENT_DEFRAG, 0, NULL))
1573                 return 1;
1574
1575         return 0;
1576 }
1577
1578 /*
1579  * extent_io.c call back to do delayed allocation processing
1580  */
1581 static int run_delalloc_range(void *private_data, struct page *locked_page,
1582                               u64 start, u64 end, int *page_started,
1583                               unsigned long *nr_written,
1584                               struct writeback_control *wbc)
1585 {
1586         struct inode *inode = private_data;
1587         int ret;
1588         int force_cow = need_force_cow(inode, start, end);
1589         unsigned int write_flags = wbc_to_write_flags(wbc);
1590
1591         if (BTRFS_I(inode)->flags & BTRFS_INODE_NODATACOW && !force_cow) {
1592                 ret = run_delalloc_nocow(inode, locked_page, start, end,
1593                                          page_started, 1, nr_written);
1594         } else if (BTRFS_I(inode)->flags & BTRFS_INODE_PREALLOC && !force_cow) {
1595                 ret = run_delalloc_nocow(inode, locked_page, start, end,
1596                                          page_started, 0, nr_written);
1597         } else if (!inode_need_compress(inode, start, end)) {
1598                 ret = cow_file_range(inode, locked_page, start, end, end,
1599                                       page_started, nr_written, 1, NULL);
1600         } else {
1601                 set_bit(BTRFS_INODE_HAS_ASYNC_EXTENT,
1602                         &BTRFS_I(inode)->runtime_flags);
1603                 ret = cow_file_range_async(inode, locked_page, start, end,
1604                                            page_started, nr_written,
1605                                            write_flags);
1606         }
1607         if (ret)
1608                 btrfs_cleanup_ordered_extents(inode, start, end - start + 1);
1609         return ret;
1610 }
1611
1612 static void btrfs_split_extent_hook(void *private_data,
1613                                     struct extent_state *orig, u64 split)
1614 {
1615         struct inode *inode = private_data;
1616         u64 size;
1617
1618         /* not delalloc, ignore it */
1619         if (!(orig->state & EXTENT_DELALLOC))
1620                 return;
1621
1622         size = orig->end - orig->start + 1;
1623         if (size > BTRFS_MAX_EXTENT_SIZE) {
1624                 u32 num_extents;
1625                 u64 new_size;
1626
1627                 /*
1628                  * See the explanation in btrfs_merge_extent_hook, the same
1629                  * applies here, just in reverse.
1630                  */
1631                 new_size = orig->end - split + 1;
1632                 num_extents = count_max_extents(new_size);
1633                 new_size = split - orig->start;
1634                 num_extents += count_max_extents(new_size);
1635                 if (count_max_extents(size) >= num_extents)
1636                         return;
1637         }
1638
1639         spin_lock(&BTRFS_I(inode)->lock);
1640         btrfs_mod_outstanding_extents(BTRFS_I(inode), 1);
1641         spin_unlock(&BTRFS_I(inode)->lock);
1642 }
1643
1644 /*
1645  * extent_io.c merge_extent_hook, used to track merged delayed allocation
1646  * extents so we can keep track of new extents that are just merged onto old
1647  * extents, such as when we are doing sequential writes, so we can properly
1648  * account for the metadata space we'll need.
1649  */
1650 static void btrfs_merge_extent_hook(void *private_data,
1651                                     struct extent_state *new,
1652                                     struct extent_state *other)
1653 {
1654         struct inode *inode = private_data;
1655         u64 new_size, old_size;
1656         u32 num_extents;
1657
1658         /* not delalloc, ignore it */
1659         if (!(other->state & EXTENT_DELALLOC))
1660                 return;
1661
1662         if (new->start > other->start)
1663                 new_size = new->end - other->start + 1;
1664         else
1665                 new_size = other->end - new->start + 1;
1666
1667         /* we're not bigger than the max, unreserve the space and go */
1668         if (new_size <= BTRFS_MAX_EXTENT_SIZE) {
1669                 spin_lock(&BTRFS_I(inode)->lock);
1670                 btrfs_mod_outstanding_extents(BTRFS_I(inode), -1);
1671                 spin_unlock(&BTRFS_I(inode)->lock);
1672                 return;
1673         }
1674
1675         /*
1676          * We have to add up either side to figure out how many extents were
1677          * accounted for before we merged into one big extent.  If the number of
1678          * extents we accounted for is <= the amount we need for the new range
1679          * then we can return, otherwise drop.  Think of it like this
1680          *
1681          * [ 4k][MAX_SIZE]
1682          *
1683          * So we've grown the extent by a MAX_SIZE extent, this would mean we
1684          * need 2 outstanding extents, on one side we have 1 and the other side
1685          * we have 1 so they are == and we can return.  But in this case
1686          *
1687          * [MAX_SIZE+4k][MAX_SIZE+4k]
1688          *
1689          * Each range on their own accounts for 2 extents, but merged together
1690          * they are only 3 extents worth of accounting, so we need to drop in
1691          * this case.
1692          */
1693         old_size = other->end - other->start + 1;
1694         num_extents = count_max_extents(old_size);
1695         old_size = new->end - new->start + 1;
1696         num_extents += count_max_extents(old_size);
1697         if (count_max_extents(new_size) >= num_extents)
1698                 return;
1699
1700         spin_lock(&BTRFS_I(inode)->lock);
1701         btrfs_mod_outstanding_extents(BTRFS_I(inode), -1);
1702         spin_unlock(&BTRFS_I(inode)->lock);
1703 }
1704
1705 static void btrfs_add_delalloc_inodes(struct btrfs_root *root,
1706                                       struct inode *inode)
1707 {
1708         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
1709
1710         spin_lock(&root->delalloc_lock);
1711         if (list_empty(&BTRFS_I(inode)->delalloc_inodes)) {
1712                 list_add_tail(&BTRFS_I(inode)->delalloc_inodes,
1713                               &root->delalloc_inodes);
1714                 set_bit(BTRFS_INODE_IN_DELALLOC_LIST,
1715                         &BTRFS_I(inode)->runtime_flags);
1716                 root->nr_delalloc_inodes++;
1717                 if (root->nr_delalloc_inodes == 1) {
1718                         spin_lock(&fs_info->delalloc_root_lock);
1719                         BUG_ON(!list_empty(&root->delalloc_root));
1720                         list_add_tail(&root->delalloc_root,
1721                                       &fs_info->delalloc_roots);
1722                         spin_unlock(&fs_info->delalloc_root_lock);
1723                 }
1724         }
1725         spin_unlock(&root->delalloc_lock);
1726 }
1727
1728
1729 void __btrfs_del_delalloc_inode(struct btrfs_root *root,
1730                                 struct btrfs_inode *inode)
1731 {
1732         struct btrfs_fs_info *fs_info = root->fs_info;
1733
1734         if (!list_empty(&inode->delalloc_inodes)) {
1735                 list_del_init(&inode->delalloc_inodes);
1736                 clear_bit(BTRFS_INODE_IN_DELALLOC_LIST,
1737                           &inode->runtime_flags);
1738                 root->nr_delalloc_inodes--;
1739                 if (!root->nr_delalloc_inodes) {
1740                         ASSERT(list_empty(&root->delalloc_inodes));
1741                         spin_lock(&fs_info->delalloc_root_lock);
1742                         BUG_ON(list_empty(&root->delalloc_root));
1743                         list_del_init(&root->delalloc_root);
1744                         spin_unlock(&fs_info->delalloc_root_lock);
1745                 }
1746         }
1747 }
1748
1749 static void btrfs_del_delalloc_inode(struct btrfs_root *root,
1750                                      struct btrfs_inode *inode)
1751 {
1752         spin_lock(&root->delalloc_lock);
1753         __btrfs_del_delalloc_inode(root, inode);
1754         spin_unlock(&root->delalloc_lock);
1755 }
1756
1757 /*
1758  * extent_io.c set_bit_hook, used to track delayed allocation
1759  * bytes in this file, and to maintain the list of inodes that
1760  * have pending delalloc work to be done.
1761  */
1762 static void btrfs_set_bit_hook(void *private_data,
1763                                struct extent_state *state, unsigned *bits)
1764 {
1765         struct inode *inode = private_data;
1766
1767         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
1768
1769         if ((*bits & EXTENT_DEFRAG) && !(*bits & EXTENT_DELALLOC))
1770                 WARN_ON(1);
1771         /*
1772          * set_bit and clear bit hooks normally require _irqsave/restore
1773          * but in this case, we are only testing for the DELALLOC
1774          * bit, which is only set or cleared with irqs on
1775          */
1776         if (!(state->state & EXTENT_DELALLOC) && (*bits & EXTENT_DELALLOC)) {
1777                 struct btrfs_root *root = BTRFS_I(inode)->root;
1778                 u64 len = state->end + 1 - state->start;
1779                 u32 num_extents = count_max_extents(len);
1780                 bool do_list = !btrfs_is_free_space_inode(BTRFS_I(inode));
1781
1782                 spin_lock(&BTRFS_I(inode)->lock);
1783                 btrfs_mod_outstanding_extents(BTRFS_I(inode), num_extents);
1784                 spin_unlock(&BTRFS_I(inode)->lock);
1785
1786                 /* For sanity tests */
1787                 if (btrfs_is_testing(fs_info))
1788                         return;
1789
1790                 percpu_counter_add_batch(&fs_info->delalloc_bytes, len,
1791                                          fs_info->delalloc_batch);
1792                 spin_lock(&BTRFS_I(inode)->lock);
1793                 BTRFS_I(inode)->delalloc_bytes += len;
1794                 if (*bits & EXTENT_DEFRAG)
1795                         BTRFS_I(inode)->defrag_bytes += len;
1796                 if (do_list && !test_bit(BTRFS_INODE_IN_DELALLOC_LIST,
1797                                          &BTRFS_I(inode)->runtime_flags))
1798                         btrfs_add_delalloc_inodes(root, inode);
1799                 spin_unlock(&BTRFS_I(inode)->lock);
1800         }
1801
1802         if (!(state->state & EXTENT_DELALLOC_NEW) &&
1803             (*bits & EXTENT_DELALLOC_NEW)) {
1804                 spin_lock(&BTRFS_I(inode)->lock);
1805                 BTRFS_I(inode)->new_delalloc_bytes += state->end + 1 -
1806                         state->start;
1807                 spin_unlock(&BTRFS_I(inode)->lock);
1808         }
1809 }
1810
1811 /*
1812  * extent_io.c clear_bit_hook, see set_bit_hook for why
1813  */
1814 static void btrfs_clear_bit_hook(void *private_data,
1815                                  struct extent_state *state,
1816                                  unsigned *bits)
1817 {
1818         struct btrfs_inode *inode = BTRFS_I((struct inode *)private_data);
1819         struct btrfs_fs_info *fs_info = btrfs_sb(inode->vfs_inode.i_sb);
1820         u64 len = state->end + 1 - state->start;
1821         u32 num_extents = count_max_extents(len);
1822
1823         if ((state->state & EXTENT_DEFRAG) && (*bits & EXTENT_DEFRAG)) {
1824                 spin_lock(&inode->lock);
1825                 inode->defrag_bytes -= len;
1826                 spin_unlock(&inode->lock);
1827         }
1828
1829         /*
1830          * set_bit and clear bit hooks normally require _irqsave/restore
1831          * but in this case, we are only testing for the DELALLOC
1832          * bit, which is only set or cleared with irqs on
1833          */
1834         if ((state->state & EXTENT_DELALLOC) && (*bits & EXTENT_DELALLOC)) {
1835                 struct btrfs_root *root = inode->root;
1836                 bool do_list = !btrfs_is_free_space_inode(inode);
1837
1838                 spin_lock(&inode->lock);
1839                 btrfs_mod_outstanding_extents(inode, -num_extents);
1840                 spin_unlock(&inode->lock);
1841
1842                 /*
1843                  * We don't reserve metadata space for space cache inodes so we
1844                  * don't need to call dellalloc_release_metadata if there is an
1845                  * error.
1846                  */
1847                 if (*bits & EXTENT_CLEAR_META_RESV &&
1848                     root != fs_info->tree_root)
1849                         btrfs_delalloc_release_metadata(inode, len, false);
1850
1851                 /* For sanity tests. */
1852                 if (btrfs_is_testing(fs_info))
1853                         return;
1854
1855                 if (root->root_key.objectid != BTRFS_DATA_RELOC_TREE_OBJECTID &&
1856                     do_list && !(state->state & EXTENT_NORESERVE) &&
1857                     (*bits & EXTENT_CLEAR_DATA_RESV))
1858                         btrfs_free_reserved_data_space_noquota(
1859                                         &inode->vfs_inode,
1860                                         state->start, len);
1861
1862                 percpu_counter_add_batch(&fs_info->delalloc_bytes, -len,
1863                                          fs_info->delalloc_batch);
1864                 spin_lock(&inode->lock);
1865                 inode->delalloc_bytes -= len;
1866                 if (do_list && inode->delalloc_bytes == 0 &&
1867                     test_bit(BTRFS_INODE_IN_DELALLOC_LIST,
1868                                         &inode->runtime_flags))
1869                         btrfs_del_delalloc_inode(root, inode);
1870                 spin_unlock(&inode->lock);
1871         }
1872
1873         if ((state->state & EXTENT_DELALLOC_NEW) &&
1874             (*bits & EXTENT_DELALLOC_NEW)) {
1875                 spin_lock(&inode->lock);
1876                 ASSERT(inode->new_delalloc_bytes >= len);
1877                 inode->new_delalloc_bytes -= len;
1878                 spin_unlock(&inode->lock);
1879         }
1880 }
1881
1882 /*
1883  * Merge bio hook, this must check the chunk tree to make sure we don't create
1884  * bios that span stripes or chunks
1885  *
1886  * return 1 if page cannot be merged to bio
1887  * return 0 if page can be merged to bio
1888  * return error otherwise
1889  */
1890 int btrfs_merge_bio_hook(struct page *page, unsigned long offset,
1891                          size_t size, struct bio *bio,
1892                          unsigned long bio_flags)
1893 {
1894         struct inode *inode = page->mapping->host;
1895         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
1896         u64 logical = (u64)bio->bi_iter.bi_sector << 9;
1897         u64 length = 0;
1898         u64 map_length;
1899         int ret;
1900
1901         if (bio_flags & EXTENT_BIO_COMPRESSED)
1902                 return 0;
1903
1904         length = bio->bi_iter.bi_size;
1905         map_length = length;
1906         ret = btrfs_map_block(fs_info, btrfs_op(bio), logical, &map_length,
1907                               NULL, 0);
1908         if (ret < 0)
1909                 return ret;
1910         if (map_length < length + size)
1911                 return 1;
1912         return 0;
1913 }
1914
1915 /*
1916  * in order to insert checksums into the metadata in large chunks,
1917  * we wait until bio submission time.   All the pages in the bio are
1918  * checksummed and sums are attached onto the ordered extent record.
1919  *
1920  * At IO completion time the cums attached on the ordered extent record
1921  * are inserted into the btree
1922  */
1923 static blk_status_t btrfs_submit_bio_start(void *private_data, struct bio *bio,
1924                                     u64 bio_offset)
1925 {
1926         struct inode *inode = private_data;
1927         blk_status_t ret = 0;
1928
1929         ret = btrfs_csum_one_bio(inode, bio, 0, 0);
1930         BUG_ON(ret); /* -ENOMEM */
1931         return 0;
1932 }
1933
1934 /*
1935  * in order to insert checksums into the metadata in large chunks,
1936  * we wait until bio submission time.   All the pages in the bio are
1937  * checksummed and sums are attached onto the ordered extent record.
1938  *
1939  * At IO completion time the cums attached on the ordered extent record
1940  * are inserted into the btree
1941  */
1942 blk_status_t btrfs_submit_bio_done(void *private_data, struct bio *bio,
1943                           int mirror_num)
1944 {
1945         struct inode *inode = private_data;
1946         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
1947         blk_status_t ret;
1948
1949         ret = btrfs_map_bio(fs_info, bio, mirror_num, 1);
1950         if (ret) {
1951                 bio->bi_status = ret;
1952                 bio_endio(bio);
1953         }
1954         return ret;
1955 }
1956
1957 /*
1958  * extent_io.c submission hook. This does the right thing for csum calculation
1959  * on write, or reading the csums from the tree before a read.
1960  *
1961  * Rules about async/sync submit,
1962  * a) read:                             sync submit
1963  *
1964  * b) write without checksum:           sync submit
1965  *
1966  * c) write with checksum:
1967  *    c-1) if bio is issued by fsync:   sync submit
1968  *         (sync_writers != 0)
1969  *
1970  *    c-2) if root is reloc root:       sync submit
1971  *         (only in case of buffered IO)
1972  *
1973  *    c-3) otherwise:                   async submit
1974  */
1975 static blk_status_t btrfs_submit_bio_hook(void *private_data, struct bio *bio,
1976                                  int mirror_num, unsigned long bio_flags,
1977                                  u64 bio_offset)
1978 {
1979         struct inode *inode = private_data;
1980         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
1981         struct btrfs_root *root = BTRFS_I(inode)->root;
1982         enum btrfs_wq_endio_type metadata = BTRFS_WQ_ENDIO_DATA;
1983         blk_status_t ret = 0;
1984         int skip_sum;
1985         int async = !atomic_read(&BTRFS_I(inode)->sync_writers);
1986
1987         skip_sum = BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM;
1988
1989         if (btrfs_is_free_space_inode(BTRFS_I(inode)))
1990                 metadata = BTRFS_WQ_ENDIO_FREE_SPACE;
1991
1992         if (bio_op(bio) != REQ_OP_WRITE) {
1993                 ret = btrfs_bio_wq_end_io(fs_info, bio, metadata);
1994                 if (ret)
1995                         goto out;
1996
1997                 if (bio_flags & EXTENT_BIO_COMPRESSED) {
1998                         ret = btrfs_submit_compressed_read(inode, bio,
1999                                                            mirror_num,
2000                                                            bio_flags);
2001                         goto out;
2002                 } else if (!skip_sum) {
2003                         ret = btrfs_lookup_bio_sums(inode, bio, NULL);
2004                         if (ret)
2005                                 goto out;
2006                 }
2007                 goto mapit;
2008         } else if (async && !skip_sum) {
2009                 /* csum items have already been cloned */
2010                 if (root->root_key.objectid == BTRFS_DATA_RELOC_TREE_OBJECTID)
2011                         goto mapit;
2012                 /* we're doing a write, do the async checksumming */
2013                 ret = btrfs_wq_submit_bio(fs_info, bio, mirror_num, bio_flags,
2014                                           bio_offset, inode,
2015                                           btrfs_submit_bio_start);
2016                 goto out;
2017         } else if (!skip_sum) {
2018                 ret = btrfs_csum_one_bio(inode, bio, 0, 0);
2019                 if (ret)
2020                         goto out;
2021         }
2022
2023 mapit:
2024         ret = btrfs_map_bio(fs_info, bio, mirror_num, 0);
2025
2026 out:
2027         if (ret) {
2028                 bio->bi_status = ret;
2029                 bio_endio(bio);
2030         }
2031         return ret;
2032 }
2033
2034 /*
2035  * given a list of ordered sums record them in the inode.  This happens
2036  * at IO completion time based on sums calculated at bio submission time.
2037  */
2038 static noinline int add_pending_csums(struct btrfs_trans_handle *trans,
2039                              struct inode *inode, struct list_head *list)
2040 {
2041         struct btrfs_ordered_sum *sum;
2042         int ret;
2043
2044         list_for_each_entry(sum, list, list) {
2045                 trans->adding_csums = true;
2046                 ret = btrfs_csum_file_blocks(trans,
2047                        BTRFS_I(inode)->root->fs_info->csum_root, sum);
2048                 trans->adding_csums = false;
2049                 if (ret)
2050                         return ret;
2051         }
2052         return 0;
2053 }
2054
2055 int btrfs_set_extent_delalloc(struct inode *inode, u64 start, u64 end,
2056                               unsigned int extra_bits,
2057                               struct extent_state **cached_state, int dedupe)
2058 {
2059         WARN_ON((end & (PAGE_SIZE - 1)) == 0);
2060         return set_extent_delalloc(&BTRFS_I(inode)->io_tree, start, end,
2061                                    extra_bits, cached_state);
2062 }
2063
2064 /* see btrfs_writepage_start_hook for details on why this is required */
2065 struct btrfs_writepage_fixup {
2066         struct page *page;
2067         struct btrfs_work work;
2068 };
2069
2070 static void btrfs_writepage_fixup_worker(struct btrfs_work *work)
2071 {
2072         struct btrfs_writepage_fixup *fixup;
2073         struct btrfs_ordered_extent *ordered;
2074         struct extent_state *cached_state = NULL;
2075         struct extent_changeset *data_reserved = NULL;
2076         struct page *page;
2077         struct inode *inode;
2078         u64 page_start;
2079         u64 page_end;
2080         int ret;
2081
2082         fixup = container_of(work, struct btrfs_writepage_fixup, work);
2083         page = fixup->page;
2084 again:
2085         lock_page(page);
2086         if (!page->mapping || !PageDirty(page) || !PageChecked(page)) {
2087                 ClearPageChecked(page);
2088                 goto out_page;
2089         }
2090
2091         inode = page->mapping->host;
2092         page_start = page_offset(page);
2093         page_end = page_offset(page) + PAGE_SIZE - 1;
2094
2095         lock_extent_bits(&BTRFS_I(inode)->io_tree, page_start, page_end,
2096                          &cached_state);
2097
2098         /* already ordered? We're done */
2099         if (PagePrivate2(page))
2100                 goto out;
2101
2102         ordered = btrfs_lookup_ordered_range(BTRFS_I(inode), page_start,
2103                                         PAGE_SIZE);
2104         if (ordered) {
2105                 unlock_extent_cached(&BTRFS_I(inode)->io_tree, page_start,
2106                                      page_end, &cached_state);
2107                 unlock_page(page);
2108                 btrfs_start_ordered_extent(inode, ordered, 1);
2109                 btrfs_put_ordered_extent(ordered);
2110                 goto again;
2111         }
2112
2113         ret = btrfs_delalloc_reserve_space(inode, &data_reserved, page_start,
2114                                            PAGE_SIZE);
2115         if (ret) {
2116                 mapping_set_error(page->mapping, ret);
2117                 end_extent_writepage(page, ret, page_start, page_end);
2118                 ClearPageChecked(page);
2119                 goto out;
2120          }
2121
2122         ret = btrfs_set_extent_delalloc(inode, page_start, page_end, 0,
2123                                         &cached_state, 0);
2124         if (ret) {
2125                 mapping_set_error(page->mapping, ret);
2126                 end_extent_writepage(page, ret, page_start, page_end);
2127                 ClearPageChecked(page);
2128                 goto out;
2129         }
2130
2131         ClearPageChecked(page);
2132         set_page_dirty(page);
2133         btrfs_delalloc_release_extents(BTRFS_I(inode), PAGE_SIZE, false);
2134 out:
2135         unlock_extent_cached(&BTRFS_I(inode)->io_tree, page_start, page_end,
2136                              &cached_state);
2137 out_page:
2138         unlock_page(page);
2139         put_page(page);
2140         kfree(fixup);
2141         extent_changeset_free(data_reserved);
2142 }
2143
2144 /*
2145  * There are a few paths in the higher layers of the kernel that directly
2146  * set the page dirty bit without asking the filesystem if it is a
2147  * good idea.  This causes problems because we want to make sure COW
2148  * properly happens and the data=ordered rules are followed.
2149  *
2150  * In our case any range that doesn't have the ORDERED bit set
2151  * hasn't been properly setup for IO.  We kick off an async process
2152  * to fix it up.  The async helper will wait for ordered extents, set
2153  * the delalloc bit and make it safe to write the page.
2154  */
2155 static int btrfs_writepage_start_hook(struct page *page, u64 start, u64 end)
2156 {
2157         struct inode *inode = page->mapping->host;
2158         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
2159         struct btrfs_writepage_fixup *fixup;
2160
2161         /* this page is properly in the ordered list */
2162         if (TestClearPagePrivate2(page))
2163                 return 0;
2164
2165         if (PageChecked(page))
2166                 return -EAGAIN;
2167
2168         fixup = kzalloc(sizeof(*fixup), GFP_NOFS);
2169         if (!fixup)
2170                 return -EAGAIN;
2171
2172         SetPageChecked(page);
2173         get_page(page);
2174         btrfs_init_work(&fixup->work, btrfs_fixup_helper,
2175                         btrfs_writepage_fixup_worker, NULL, NULL);
2176         fixup->page = page;
2177         btrfs_queue_work(fs_info->fixup_workers, &fixup->work);
2178         return -EBUSY;
2179 }
2180
2181 static int insert_reserved_file_extent(struct btrfs_trans_handle *trans,
2182                                        struct inode *inode, u64 file_pos,
2183                                        u64 disk_bytenr, u64 disk_num_bytes,
2184                                        u64 num_bytes, u64 ram_bytes,
2185                                        u8 compression, u8 encryption,
2186                                        u16 other_encoding, int extent_type)
2187 {
2188         struct btrfs_root *root = BTRFS_I(inode)->root;
2189         struct btrfs_file_extent_item *fi;
2190         struct btrfs_path *path;
2191         struct extent_buffer *leaf;
2192         struct btrfs_key ins;
2193         u64 qg_released;
2194         int extent_inserted = 0;
2195         int ret;
2196
2197         path = btrfs_alloc_path();
2198         if (!path)
2199                 return -ENOMEM;
2200
2201         /*
2202          * we may be replacing one extent in the tree with another.
2203          * The new extent is pinned in the extent map, and we don't want
2204          * to drop it from the cache until it is completely in the btree.
2205          *
2206          * So, tell btrfs_drop_extents to leave this extent in the cache.
2207          * the caller is expected to unpin it and allow it to be merged
2208          * with the others.
2209          */
2210         ret = __btrfs_drop_extents(trans, root, inode, path, file_pos,
2211                                    file_pos + num_bytes, NULL, 0,
2212                                    1, sizeof(*fi), &extent_inserted);
2213         if (ret)
2214                 goto out;
2215
2216         if (!extent_inserted) {
2217                 ins.objectid = btrfs_ino(BTRFS_I(inode));
2218                 ins.offset = file_pos;
2219                 ins.type = BTRFS_EXTENT_DATA_KEY;
2220
2221                 path->leave_spinning = 1;
2222                 ret = btrfs_insert_empty_item(trans, root, path, &ins,
2223                                               sizeof(*fi));
2224                 if (ret)
2225                         goto out;
2226         }
2227         leaf = path->nodes[0];
2228         fi = btrfs_item_ptr(leaf, path->slots[0],
2229                             struct btrfs_file_extent_item);
2230         btrfs_set_file_extent_generation(leaf, fi, trans->transid);
2231         btrfs_set_file_extent_type(leaf, fi, extent_type);
2232         btrfs_set_file_extent_disk_bytenr(leaf, fi, disk_bytenr);
2233         btrfs_set_file_extent_disk_num_bytes(leaf, fi, disk_num_bytes);
2234         btrfs_set_file_extent_offset(leaf, fi, 0);
2235         btrfs_set_file_extent_num_bytes(leaf, fi, num_bytes);
2236         btrfs_set_file_extent_ram_bytes(leaf, fi, ram_bytes);
2237         btrfs_set_file_extent_compression(leaf, fi, compression);
2238         btrfs_set_file_extent_encryption(leaf, fi, encryption);
2239         btrfs_set_file_extent_other_encoding(leaf, fi, other_encoding);
2240
2241         btrfs_mark_buffer_dirty(leaf);
2242         btrfs_release_path(path);
2243
2244         inode_add_bytes(inode, num_bytes);
2245
2246         ins.objectid = disk_bytenr;
2247         ins.offset = disk_num_bytes;
2248         ins.type = BTRFS_EXTENT_ITEM_KEY;
2249
2250         /*
2251          * Release the reserved range from inode dirty range map, as it is
2252          * already moved into delayed_ref_head
2253          */
2254         ret = btrfs_qgroup_release_data(inode, file_pos, ram_bytes);
2255         if (ret < 0)
2256                 goto out;
2257         qg_released = ret;
2258         ret = btrfs_alloc_reserved_file_extent(trans, root,
2259                                                btrfs_ino(BTRFS_I(inode)),
2260                                                file_pos, qg_released, &ins);
2261 out:
2262         btrfs_free_path(path);
2263
2264         return ret;
2265 }
2266
2267 /* snapshot-aware defrag */
2268 struct sa_defrag_extent_backref {
2269         struct rb_node node;
2270         struct old_sa_defrag_extent *old;
2271         u64 root_id;
2272         u64 inum;
2273         u64 file_pos;
2274         u64 extent_offset;
2275         u64 num_bytes;
2276         u64 generation;
2277 };
2278
2279 struct old_sa_defrag_extent {
2280         struct list_head list;
2281         struct new_sa_defrag_extent *new;
2282
2283         u64 extent_offset;
2284         u64 bytenr;
2285         u64 offset;
2286         u64 len;
2287         int count;
2288 };
2289
2290 struct new_sa_defrag_extent {
2291         struct rb_root root;
2292         struct list_head head;
2293         struct btrfs_path *path;
2294         struct inode *inode;
2295         u64 file_pos;
2296         u64 len;
2297         u64 bytenr;
2298         u64 disk_len;
2299         u8 compress_type;
2300 };
2301
2302 static int backref_comp(struct sa_defrag_extent_backref *b1,
2303                         struct sa_defrag_extent_backref *b2)
2304 {
2305         if (b1->root_id < b2->root_id)
2306                 return -1;
2307         else if (b1->root_id > b2->root_id)
2308                 return 1;
2309
2310         if (b1->inum < b2->inum)
2311                 return -1;
2312         else if (b1->inum > b2->inum)
2313                 return 1;
2314
2315         if (b1->file_pos < b2->file_pos)
2316                 return -1;
2317         else if (b1->file_pos > b2->file_pos)
2318                 return 1;
2319
2320         /*
2321          * [------------------------------] ===> (a range of space)
2322          *     |<--->|   |<---->| =============> (fs/file tree A)
2323          * |<---------------------------->| ===> (fs/file tree B)
2324          *
2325          * A range of space can refer to two file extents in one tree while
2326          * refer to only one file extent in another tree.
2327          *
2328          * So we may process a disk offset more than one time(two extents in A)
2329          * and locate at the same extent(one extent in B), then insert two same
2330          * backrefs(both refer to the extent in B).
2331          */
2332         return 0;
2333 }
2334
2335 static void backref_insert(struct rb_root *root,
2336                            struct sa_defrag_extent_backref *backref)
2337 {
2338         struct rb_node **p = &root->rb_node;
2339         struct rb_node *parent = NULL;
2340         struct sa_defrag_extent_backref *entry;
2341         int ret;
2342
2343         while (*p) {
2344                 parent = *p;
2345                 entry = rb_entry(parent, struct sa_defrag_extent_backref, node);
2346
2347                 ret = backref_comp(backref, entry);
2348                 if (ret < 0)
2349                         p = &(*p)->rb_left;
2350                 else
2351                         p = &(*p)->rb_right;
2352         }
2353
2354         rb_link_node(&backref->node, parent, p);
2355         rb_insert_color(&backref->node, root);
2356 }
2357
2358 /*
2359  * Note the backref might has changed, and in this case we just return 0.
2360  */
2361 static noinline int record_one_backref(u64 inum, u64 offset, u64 root_id,
2362                                        void *ctx)
2363 {
2364         struct btrfs_file_extent_item *extent;
2365         struct old_sa_defrag_extent *old = ctx;
2366         struct new_sa_defrag_extent *new = old->new;
2367         struct btrfs_path *path = new->path;
2368         struct btrfs_key key;
2369         struct btrfs_root *root;
2370         struct sa_defrag_extent_backref *backref;
2371         struct extent_buffer *leaf;
2372         struct inode *inode = new->inode;
2373         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
2374         int slot;
2375         int ret;
2376         u64 extent_offset;
2377         u64 num_bytes;
2378
2379         if (BTRFS_I(inode)->root->root_key.objectid == root_id &&
2380             inum == btrfs_ino(BTRFS_I(inode)))
2381                 return 0;
2382
2383         key.objectid = root_id;
2384         key.type = BTRFS_ROOT_ITEM_KEY;
2385         key.offset = (u64)-1;
2386
2387         root = btrfs_read_fs_root_no_name(fs_info, &key);
2388         if (IS_ERR(root)) {
2389                 if (PTR_ERR(root) == -ENOENT)
2390                         return 0;
2391                 WARN_ON(1);
2392                 btrfs_debug(fs_info, "inum=%llu, offset=%llu, root_id=%llu",
2393                          inum, offset, root_id);
2394                 return PTR_ERR(root);
2395         }
2396
2397         key.objectid = inum;
2398         key.type = BTRFS_EXTENT_DATA_KEY;
2399         if (offset > (u64)-1 << 32)
2400                 key.offset = 0;
2401         else
2402                 key.offset = offset;
2403
2404         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
2405         if (WARN_ON(ret < 0))
2406                 return ret;
2407         ret = 0;
2408
2409         while (1) {
2410                 cond_resched();
2411
2412                 leaf = path->nodes[0];
2413                 slot = path->slots[0];
2414
2415                 if (slot >= btrfs_header_nritems(leaf)) {
2416                         ret = btrfs_next_leaf(root, path);
2417                         if (ret < 0) {
2418                                 goto out;
2419                         } else if (ret > 0) {
2420                                 ret = 0;
2421                                 goto out;
2422                         }
2423                         continue;
2424                 }
2425
2426                 path->slots[0]++;
2427
2428                 btrfs_item_key_to_cpu(leaf, &key, slot);
2429
2430                 if (key.objectid > inum)
2431                         goto out;
2432
2433                 if (key.objectid < inum || key.type != BTRFS_EXTENT_DATA_KEY)
2434                         continue;
2435
2436                 extent = btrfs_item_ptr(leaf, slot,
2437                                         struct btrfs_file_extent_item);
2438
2439                 if (btrfs_file_extent_disk_bytenr(leaf, extent) != old->bytenr)
2440                         continue;
2441
2442                 /*
2443                  * 'offset' refers to the exact key.offset,
2444                  * NOT the 'offset' field in btrfs_extent_data_ref, ie.
2445                  * (key.offset - extent_offset).
2446                  */
2447                 if (key.offset != offset)
2448                         continue;
2449
2450                 extent_offset = btrfs_file_extent_offset(leaf, extent);
2451                 num_bytes = btrfs_file_extent_num_bytes(leaf, extent);
2452
2453                 if (extent_offset >= old->extent_offset + old->offset +
2454                     old->len || extent_offset + num_bytes <=
2455                     old->extent_offset + old->offset)
2456                         continue;
2457                 break;
2458         }
2459
2460         backref = kmalloc(sizeof(*backref), GFP_NOFS);
2461         if (!backref) {
2462                 ret = -ENOENT;
2463                 goto out;
2464         }
2465
2466         backref->root_id = root_id;
2467         backref->inum = inum;
2468         backref->file_pos = offset;
2469         backref->num_bytes = num_bytes;
2470         backref->extent_offset = extent_offset;
2471         backref->generation = btrfs_file_extent_generation(leaf, extent);
2472         backref->old = old;
2473         backref_insert(&new->root, backref);
2474         old->count++;
2475 out:
2476         btrfs_release_path(path);
2477         WARN_ON(ret);
2478         return ret;
2479 }
2480
2481 static noinline bool record_extent_backrefs(struct btrfs_path *path,
2482                                    struct new_sa_defrag_extent *new)
2483 {
2484         struct btrfs_fs_info *fs_info = btrfs_sb(new->inode->i_sb);
2485         struct old_sa_defrag_extent *old, *tmp;
2486         int ret;
2487
2488         new->path = path;
2489
2490         list_for_each_entry_safe(old, tmp, &new->head, list) {
2491                 ret = iterate_inodes_from_logical(old->bytenr +
2492                                                   old->extent_offset, fs_info,
2493                                                   path, record_one_backref,
2494                                                   old, false);
2495                 if (ret < 0 && ret != -ENOENT)
2496                         return false;
2497
2498                 /* no backref to be processed for this extent */
2499                 if (!old->count) {
2500                         list_del(&old->list);
2501                         kfree(old);
2502                 }
2503         }
2504
2505         if (list_empty(&new->head))
2506                 return false;
2507
2508         return true;
2509 }
2510
2511 static int relink_is_mergable(struct extent_buffer *leaf,
2512                               struct btrfs_file_extent_item *fi,
2513                               struct new_sa_defrag_extent *new)
2514 {
2515         if (btrfs_file_extent_disk_bytenr(leaf, fi) != new->bytenr)
2516                 return 0;
2517
2518         if (btrfs_file_extent_type(leaf, fi) != BTRFS_FILE_EXTENT_REG)
2519                 return 0;
2520
2521         if (btrfs_file_extent_compression(leaf, fi) != new->compress_type)
2522                 return 0;
2523
2524         if (btrfs_file_extent_encryption(leaf, fi) ||
2525             btrfs_file_extent_other_encoding(leaf, fi))
2526                 return 0;
2527
2528         return 1;
2529 }
2530
2531 /*
2532  * Note the backref might has changed, and in this case we just return 0.
2533  */
2534 static noinline int relink_extent_backref(struct btrfs_path *path,
2535                                  struct sa_defrag_extent_backref *prev,
2536                                  struct sa_defrag_extent_backref *backref)
2537 {
2538         struct btrfs_file_extent_item *extent;
2539         struct btrfs_file_extent_item *item;
2540         struct btrfs_ordered_extent *ordered;
2541         struct btrfs_trans_handle *trans;
2542         struct btrfs_root *root;
2543         struct btrfs_key key;
2544         struct extent_buffer *leaf;
2545         struct old_sa_defrag_extent *old = backref->old;
2546         struct new_sa_defrag_extent *new = old->new;
2547         struct btrfs_fs_info *fs_info = btrfs_sb(new->inode->i_sb);
2548         struct inode *inode;
2549         struct extent_state *cached = NULL;
2550         int ret = 0;
2551         u64 start;
2552         u64 len;
2553         u64 lock_start;
2554         u64 lock_end;
2555         bool merge = false;
2556         int index;
2557
2558         if (prev && prev->root_id == backref->root_id &&
2559             prev->inum == backref->inum &&
2560             prev->file_pos + prev->num_bytes == backref->file_pos)
2561                 merge = true;
2562
2563         /* step 1: get root */
2564         key.objectid = backref->root_id;
2565         key.type = BTRFS_ROOT_ITEM_KEY;
2566         key.offset = (u64)-1;
2567
2568         index = srcu_read_lock(&fs_info->subvol_srcu);
2569
2570         root = btrfs_read_fs_root_no_name(fs_info, &key);
2571         if (IS_ERR(root)) {
2572                 srcu_read_unlock(&fs_info->subvol_srcu, index);
2573                 if (PTR_ERR(root) == -ENOENT)
2574                         return 0;
2575                 return PTR_ERR(root);
2576         }
2577
2578         if (btrfs_root_readonly(root)) {
2579                 srcu_read_unlock(&fs_info->subvol_srcu, index);
2580                 return 0;
2581         }
2582
2583         /* step 2: get inode */
2584         key.objectid = backref->inum;
2585         key.type = BTRFS_INODE_ITEM_KEY;
2586         key.offset = 0;
2587
2588         inode = btrfs_iget(fs_info->sb, &key, root, NULL);
2589         if (IS_ERR(inode)) {
2590                 srcu_read_unlock(&fs_info->subvol_srcu, index);
2591                 return 0;
2592         }
2593
2594         srcu_read_unlock(&fs_info->subvol_srcu, index);
2595
2596         /* step 3: relink backref */
2597         lock_start = backref->file_pos;
2598         lock_end = backref->file_pos + backref->num_bytes - 1;
2599         lock_extent_bits(&BTRFS_I(inode)->io_tree, lock_start, lock_end,
2600                          &cached);
2601
2602         ordered = btrfs_lookup_first_ordered_extent(inode, lock_end);
2603         if (ordered) {
2604                 btrfs_put_ordered_extent(ordered);
2605                 goto out_unlock;
2606         }
2607
2608         trans = btrfs_join_transaction(root);
2609         if (IS_ERR(trans)) {
2610                 ret = PTR_ERR(trans);
2611                 goto out_unlock;
2612         }
2613
2614         key.objectid = backref->inum;
2615         key.type = BTRFS_EXTENT_DATA_KEY;
2616         key.offset = backref->file_pos;
2617
2618         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
2619         if (ret < 0) {
2620                 goto out_free_path;
2621         } else if (ret > 0) {
2622                 ret = 0;
2623                 goto out_free_path;
2624         }
2625
2626         extent = btrfs_item_ptr(path->nodes[0], path->slots[0],
2627                                 struct btrfs_file_extent_item);
2628
2629         if (btrfs_file_extent_generation(path->nodes[0], extent) !=
2630             backref->generation)
2631                 goto out_free_path;
2632
2633         btrfs_release_path(path);
2634
2635         start = backref->file_pos;
2636         if (backref->extent_offset < old->extent_offset + old->offset)
2637                 start += old->extent_offset + old->offset -
2638                          backref->extent_offset;
2639
2640         len = min(backref->extent_offset + backref->num_bytes,
2641                   old->extent_offset + old->offset + old->len);
2642         len -= max(backref->extent_offset, old->extent_offset + old->offset);
2643
2644         ret = btrfs_drop_extents(trans, root, inode, start,
2645                                  start + len, 1);
2646         if (ret)
2647                 goto out_free_path;
2648 again:
2649         key.objectid = btrfs_ino(BTRFS_I(inode));
2650         key.type = BTRFS_EXTENT_DATA_KEY;
2651         key.offset = start;
2652
2653         path->leave_spinning = 1;
2654         if (merge) {
2655                 struct btrfs_file_extent_item *fi;
2656                 u64 extent_len;
2657                 struct btrfs_key found_key;
2658
2659                 ret = btrfs_search_slot(trans, root, &key, path, 0, 1);
2660                 if (ret < 0)
2661                         goto out_free_path;
2662
2663                 path->slots[0]--;
2664                 leaf = path->nodes[0];
2665                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
2666
2667                 fi = btrfs_item_ptr(leaf, path->slots[0],
2668                                     struct btrfs_file_extent_item);
2669                 extent_len = btrfs_file_extent_num_bytes(leaf, fi);
2670
2671                 if (extent_len + found_key.offset == start &&
2672                     relink_is_mergable(leaf, fi, new)) {
2673                         btrfs_set_file_extent_num_bytes(leaf, fi,
2674                                                         extent_len + len);
2675                         btrfs_mark_buffer_dirty(leaf);
2676                         inode_add_bytes(inode, len);
2677
2678                         ret = 1;
2679                         goto out_free_path;
2680                 } else {
2681                         merge = false;
2682                         btrfs_release_path(path);
2683                         goto again;
2684                 }
2685         }
2686
2687         ret = btrfs_insert_empty_item(trans, root, path, &key,
2688                                         sizeof(*extent));
2689         if (ret) {
2690                 btrfs_abort_transaction(trans, ret);
2691                 goto out_free_path;
2692         }
2693
2694         leaf = path->nodes[0];
2695         item = btrfs_item_ptr(leaf, path->slots[0],
2696                                 struct btrfs_file_extent_item);
2697         btrfs_set_file_extent_disk_bytenr(leaf, item, new->bytenr);
2698         btrfs_set_file_extent_disk_num_bytes(leaf, item, new->disk_len);
2699         btrfs_set_file_extent_offset(leaf, item, start - new->file_pos);
2700         btrfs_set_file_extent_num_bytes(leaf, item, len);
2701         btrfs_set_file_extent_ram_bytes(leaf, item, new->len);
2702         btrfs_set_file_extent_generation(leaf, item, trans->transid);
2703         btrfs_set_file_extent_type(leaf, item, BTRFS_FILE_EXTENT_REG);
2704         btrfs_set_file_extent_compression(leaf, item, new->compress_type);
2705         btrfs_set_file_extent_encryption(leaf, item, 0);
2706         btrfs_set_file_extent_other_encoding(leaf, item, 0);
2707
2708         btrfs_mark_buffer_dirty(leaf);
2709         inode_add_bytes(inode, len);
2710         btrfs_release_path(path);
2711
2712         ret = btrfs_inc_extent_ref(trans, root, new->bytenr,
2713                         new->disk_len, 0,
2714                         backref->root_id, backref->inum,
2715                         new->file_pos); /* start - extent_offset */
2716         if (ret) {
2717                 btrfs_abort_transaction(trans, ret);
2718                 goto out_free_path;
2719         }
2720
2721         ret = 1;
2722 out_free_path:
2723         btrfs_release_path(path);
2724         path->leave_spinning = 0;
2725         btrfs_end_transaction(trans);
2726 out_unlock:
2727         unlock_extent_cached(&BTRFS_I(inode)->io_tree, lock_start, lock_end,
2728                              &cached);
2729         iput(inode);
2730         return ret;
2731 }
2732
2733 static void free_sa_defrag_extent(struct new_sa_defrag_extent *new)
2734 {
2735         struct old_sa_defrag_extent *old, *tmp;
2736
2737         if (!new)
2738                 return;
2739
2740         list_for_each_entry_safe(old, tmp, &new->head, list) {
2741                 kfree(old);
2742         }
2743         kfree(new);
2744 }
2745
2746 static void relink_file_extents(struct new_sa_defrag_extent *new)
2747 {
2748         struct btrfs_fs_info *fs_info = btrfs_sb(new->inode->i_sb);
2749         struct btrfs_path *path;
2750         struct sa_defrag_extent_backref *backref;
2751         struct sa_defrag_extent_backref *prev = NULL;
2752         struct rb_node *node;
2753         int ret;
2754
2755         path = btrfs_alloc_path();
2756         if (!path)
2757                 return;
2758
2759         if (!record_extent_backrefs(path, new)) {
2760                 btrfs_free_path(path);
2761                 goto out;
2762         }
2763         btrfs_release_path(path);
2764
2765         while (1) {
2766                 node = rb_first(&new->root);
2767                 if (!node)
2768                         break;
2769                 rb_erase(node, &new->root);
2770
2771                 backref = rb_entry(node, struct sa_defrag_extent_backref, node);
2772
2773                 ret = relink_extent_backref(path, prev, backref);
2774                 WARN_ON(ret < 0);
2775
2776                 kfree(prev);
2777
2778                 if (ret == 1)
2779                         prev = backref;
2780                 else
2781                         prev = NULL;
2782                 cond_resched();
2783         }
2784         kfree(prev);
2785
2786         btrfs_free_path(path);
2787 out:
2788         free_sa_defrag_extent(new);
2789
2790         atomic_dec(&fs_info->defrag_running);
2791         wake_up(&fs_info->transaction_wait);
2792 }
2793
2794 static struct new_sa_defrag_extent *
2795 record_old_file_extents(struct inode *inode,
2796                         struct btrfs_ordered_extent *ordered)
2797 {
2798         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
2799         struct btrfs_root *root = BTRFS_I(inode)->root;
2800         struct btrfs_path *path;
2801         struct btrfs_key key;
2802         struct old_sa_defrag_extent *old;
2803         struct new_sa_defrag_extent *new;
2804         int ret;
2805
2806         new = kmalloc(sizeof(*new), GFP_NOFS);
2807         if (!new)
2808                 return NULL;
2809
2810         new->inode = inode;
2811         new->file_pos = ordered->file_offset;
2812         new->len = ordered->len;
2813         new->bytenr = ordered->start;
2814         new->disk_len = ordered->disk_len;
2815         new->compress_type = ordered->compress_type;
2816         new->root = RB_ROOT;
2817         INIT_LIST_HEAD(&new->head);
2818
2819         path = btrfs_alloc_path();
2820         if (!path)
2821                 goto out_kfree;
2822
2823         key.objectid = btrfs_ino(BTRFS_I(inode));
2824         key.type = BTRFS_EXTENT_DATA_KEY;
2825         key.offset = new->file_pos;
2826
2827         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
2828         if (ret < 0)
2829                 goto out_free_path;
2830         if (ret > 0 && path->slots[0] > 0)
2831                 path->slots[0]--;
2832
2833         /* find out all the old extents for the file range */
2834         while (1) {
2835                 struct btrfs_file_extent_item *extent;
2836                 struct extent_buffer *l;
2837                 int slot;
2838                 u64 num_bytes;
2839                 u64 offset;
2840                 u64 end;
2841                 u64 disk_bytenr;
2842                 u64 extent_offset;
2843
2844                 l = path->nodes[0];
2845                 slot = path->slots[0];
2846
2847                 if (slot >= btrfs_header_nritems(l)) {
2848                         ret = btrfs_next_leaf(root, path);
2849                         if (ret < 0)
2850                                 goto out_free_path;
2851                         else if (ret > 0)
2852                                 break;
2853                         continue;
2854                 }
2855
2856                 btrfs_item_key_to_cpu(l, &key, slot);
2857
2858                 if (key.objectid != btrfs_ino(BTRFS_I(inode)))
2859                         break;
2860                 if (key.type != BTRFS_EXTENT_DATA_KEY)
2861                         break;
2862                 if (key.offset >= new->file_pos + new->len)
2863                         break;
2864
2865                 extent = btrfs_item_ptr(l, slot, struct btrfs_file_extent_item);
2866
2867                 num_bytes = btrfs_file_extent_num_bytes(l, extent);
2868                 if (key.offset + num_bytes < new->file_pos)
2869                         goto next;
2870
2871                 disk_bytenr = btrfs_file_extent_disk_bytenr(l, extent);
2872                 if (!disk_bytenr)
2873                         goto next;
2874
2875                 extent_offset = btrfs_file_extent_offset(l, extent);
2876
2877                 old = kmalloc(sizeof(*old), GFP_NOFS);
2878                 if (!old)
2879                         goto out_free_path;
2880
2881                 offset = max(new->file_pos, key.offset);
2882                 end = min(new->file_pos + new->len, key.offset + num_bytes);
2883
2884                 old->bytenr = disk_bytenr;
2885                 old->extent_offset = extent_offset;
2886                 old->offset = offset - key.offset;
2887                 old->len = end - offset;
2888                 old->new = new;
2889                 old->count = 0;
2890                 list_add_tail(&old->list, &new->head);
2891 next:
2892                 path->slots[0]++;
2893                 cond_resched();
2894         }
2895
2896         btrfs_free_path(path);
2897         atomic_inc(&fs_info->defrag_running);
2898
2899         return new;
2900
2901 out_free_path:
2902         btrfs_free_path(path);
2903 out_kfree:
2904         free_sa_defrag_extent(new);
2905         return NULL;
2906 }
2907
2908 static void btrfs_release_delalloc_bytes(struct btrfs_fs_info *fs_info,
2909                                          u64 start, u64 len)
2910 {
2911         struct btrfs_block_group_cache *cache;
2912
2913         cache = btrfs_lookup_block_group(fs_info, start);
2914         ASSERT(cache);
2915
2916         spin_lock(&cache->lock);
2917         cache->delalloc_bytes -= len;
2918         spin_unlock(&cache->lock);
2919
2920         btrfs_put_block_group(cache);
2921 }
2922
2923 /* as ordered data IO finishes, this gets called so we can finish
2924  * an ordered extent if the range of bytes in the file it covers are
2925  * fully written.
2926  */
2927 static int btrfs_finish_ordered_io(struct btrfs_ordered_extent *ordered_extent)
2928 {
2929         struct inode *inode = ordered_extent->inode;
2930         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
2931         struct btrfs_root *root = BTRFS_I(inode)->root;
2932         struct btrfs_trans_handle *trans = NULL;
2933         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
2934         struct extent_state *cached_state = NULL;
2935         struct new_sa_defrag_extent *new = NULL;
2936         int compress_type = 0;
2937         int ret = 0;
2938         u64 logical_len = ordered_extent->len;
2939         bool nolock;
2940         bool truncated = false;
2941         bool range_locked = false;
2942         bool clear_new_delalloc_bytes = false;
2943
2944         if (!test_bit(BTRFS_ORDERED_NOCOW, &ordered_extent->flags) &&
2945             !test_bit(BTRFS_ORDERED_PREALLOC, &ordered_extent->flags) &&
2946             !test_bit(BTRFS_ORDERED_DIRECT, &ordered_extent->flags))
2947                 clear_new_delalloc_bytes = true;
2948
2949         nolock = btrfs_is_free_space_inode(BTRFS_I(inode));
2950
2951         if (test_bit(BTRFS_ORDERED_IOERR, &ordered_extent->flags)) {
2952                 ret = -EIO;
2953                 goto out;
2954         }
2955
2956         btrfs_free_io_failure_record(BTRFS_I(inode),
2957                         ordered_extent->file_offset,
2958                         ordered_extent->file_offset +
2959                         ordered_extent->len - 1);
2960
2961         if (test_bit(BTRFS_ORDERED_TRUNCATED, &ordered_extent->flags)) {
2962                 truncated = true;
2963                 logical_len = ordered_extent->truncated_len;
2964                 /* Truncated the entire extent, don't bother adding */
2965                 if (!logical_len)
2966                         goto out;
2967         }
2968
2969         if (test_bit(BTRFS_ORDERED_NOCOW, &ordered_extent->flags)) {
2970                 BUG_ON(!list_empty(&ordered_extent->list)); /* Logic error */
2971
2972                 /*
2973                  * For mwrite(mmap + memset to write) case, we still reserve
2974                  * space for NOCOW range.
2975                  * As NOCOW won't cause a new delayed ref, just free the space
2976                  */
2977                 btrfs_qgroup_free_data(inode, NULL, ordered_extent->file_offset,
2978                                        ordered_extent->len);
2979                 btrfs_ordered_update_i_size(inode, 0, ordered_extent);
2980                 if (nolock)
2981                         trans = btrfs_join_transaction_nolock(root);
2982                 else
2983                         trans = btrfs_join_transaction(root);
2984                 if (IS_ERR(trans)) {
2985                         ret = PTR_ERR(trans);
2986                         trans = NULL;
2987                         goto out;
2988                 }
2989                 trans->block_rsv = &BTRFS_I(inode)->block_rsv;
2990                 ret = btrfs_update_inode_fallback(trans, root, inode);
2991                 if (ret) /* -ENOMEM or corruption */
2992                         btrfs_abort_transaction(trans, ret);
2993                 goto out;
2994         }
2995
2996         range_locked = true;
2997         lock_extent_bits(io_tree, ordered_extent->file_offset,
2998                          ordered_extent->file_offset + ordered_extent->len - 1,
2999                          &cached_state);
3000
3001         ret = test_range_bit(io_tree, ordered_extent->file_offset,
3002                         ordered_extent->file_offset + ordered_extent->len - 1,
3003                         EXTENT_DEFRAG, 0, cached_state);
3004         if (ret) {
3005                 u64 last_snapshot = btrfs_root_last_snapshot(&root->root_item);
3006                 if (0 && last_snapshot >= BTRFS_I(inode)->generation)
3007                         /* the inode is shared */
3008                         new = record_old_file_extents(inode, ordered_extent);
3009
3010                 clear_extent_bit(io_tree, ordered_extent->file_offset,
3011                         ordered_extent->file_offset + ordered_extent->len - 1,
3012                         EXTENT_DEFRAG, 0, 0, &cached_state);
3013         }
3014
3015         if (nolock)
3016                 trans = btrfs_join_transaction_nolock(root);
3017         else
3018                 trans = btrfs_join_transaction(root);
3019         if (IS_ERR(trans)) {
3020                 ret = PTR_ERR(trans);
3021                 trans = NULL;
3022                 goto out;
3023         }
3024
3025         trans->block_rsv = &BTRFS_I(inode)->block_rsv;
3026
3027         if (test_bit(BTRFS_ORDERED_COMPRESSED, &ordered_extent->flags))
3028                 compress_type = ordered_extent->compress_type;
3029         if (test_bit(BTRFS_ORDERED_PREALLOC, &ordered_extent->flags)) {
3030                 BUG_ON(compress_type);
3031                 btrfs_qgroup_free_data(inode, NULL, ordered_extent->file_offset,
3032                                        ordered_extent->len);
3033                 ret = btrfs_mark_extent_written(trans, BTRFS_I(inode),
3034                                                 ordered_extent->file_offset,
3035                                                 ordered_extent->file_offset +
3036                                                 logical_len);
3037         } else {
3038                 BUG_ON(root == fs_info->tree_root);
3039                 ret = insert_reserved_file_extent(trans, inode,
3040                                                 ordered_extent->file_offset,
3041                                                 ordered_extent->start,
3042                                                 ordered_extent->disk_len,
3043                                                 logical_len, logical_len,
3044                                                 compress_type, 0, 0,
3045                                                 BTRFS_FILE_EXTENT_REG);
3046                 if (!ret)
3047                         btrfs_release_delalloc_bytes(fs_info,
3048                                                      ordered_extent->start,
3049                                                      ordered_extent->disk_len);
3050         }
3051         unpin_extent_cache(&BTRFS_I(inode)->extent_tree,
3052                            ordered_extent->file_offset, ordered_extent->len,
3053                            trans->transid);
3054         if (ret < 0) {
3055                 btrfs_abort_transaction(trans, ret);
3056                 goto out;
3057         }
3058
3059         ret = add_pending_csums(trans, inode, &ordered_extent->list);
3060         if (ret) {
3061                 btrfs_abort_transaction(trans, ret);
3062                 goto out;
3063         }
3064
3065         btrfs_ordered_update_i_size(inode, 0, ordered_extent);
3066         ret = btrfs_update_inode_fallback(trans, root, inode);
3067         if (ret) { /* -ENOMEM or corruption */
3068                 btrfs_abort_transaction(trans, ret);
3069                 goto out;
3070         }
3071         ret = 0;
3072 out:
3073         if (range_locked || clear_new_delalloc_bytes) {
3074                 unsigned int clear_bits = 0;
3075
3076                 if (range_locked)
3077                         clear_bits |= EXTENT_LOCKED;
3078                 if (clear_new_delalloc_bytes)
3079                         clear_bits |= EXTENT_DELALLOC_NEW;
3080                 clear_extent_bit(&BTRFS_I(inode)->io_tree,
3081                                  ordered_extent->file_offset,
3082                                  ordered_extent->file_offset +
3083                                  ordered_extent->len - 1,
3084                                  clear_bits,
3085                                  (clear_bits & EXTENT_LOCKED) ? 1 : 0,
3086                                  0, &cached_state);
3087         }
3088
3089         if (trans)
3090                 btrfs_end_transaction(trans);
3091
3092         if (ret || truncated) {
3093                 u64 start, end;
3094
3095                 if (truncated)
3096                         start = ordered_extent->file_offset + logical_len;
3097                 else
3098                         start = ordered_extent->file_offset;
3099                 end = ordered_extent->file_offset + ordered_extent->len - 1;
3100                 clear_extent_uptodate(io_tree, start, end, NULL);
3101
3102                 /* Drop the cache for the part of the extent we didn't write. */
3103                 btrfs_drop_extent_cache(BTRFS_I(inode), start, end, 0);
3104
3105                 /*
3106                  * If the ordered extent had an IOERR or something else went
3107                  * wrong we need to return the space for this ordered extent
3108                  * back to the allocator.  We only free the extent in the
3109                  * truncated case if we didn't write out the extent at all.
3110                  */
3111                 if ((ret || !logical_len) &&
3112                     !test_bit(BTRFS_ORDERED_NOCOW, &ordered_extent->flags) &&
3113                     !test_bit(BTRFS_ORDERED_PREALLOC, &ordered_extent->flags))
3114                         btrfs_free_reserved_extent(fs_info,
3115                                                    ordered_extent->start,
3116                                                    ordered_extent->disk_len, 1);
3117         }
3118
3119
3120         /*
3121          * This needs to be done to make sure anybody waiting knows we are done
3122          * updating everything for this ordered extent.
3123          */
3124         btrfs_remove_ordered_extent(inode, ordered_extent);
3125
3126         /* for snapshot-aware defrag */
3127         if (new) {
3128                 if (ret) {
3129                         free_sa_defrag_extent(new);
3130                         atomic_dec(&fs_info->defrag_running);
3131                 } else {
3132                         relink_file_extents(new);
3133                 }
3134         }
3135
3136         /* once for us */
3137         btrfs_put_ordered_extent(ordered_extent);
3138         /* once for the tree */
3139         btrfs_put_ordered_extent(ordered_extent);
3140
3141         /* Try to release some metadata so we don't get an OOM but don't wait */
3142         btrfs_btree_balance_dirty_nodelay(fs_info);
3143
3144         return ret;
3145 }
3146
3147 static void finish_ordered_fn(struct btrfs_work *work)
3148 {
3149         struct btrfs_ordered_extent *ordered_extent;
3150         ordered_extent = container_of(work, struct btrfs_ordered_extent, work);
3151         btrfs_finish_ordered_io(ordered_extent);
3152 }
3153
3154 static void btrfs_writepage_end_io_hook(struct page *page, u64 start, u64 end,
3155                                 struct extent_state *state, int uptodate)
3156 {
3157         struct inode *inode = page->mapping->host;
3158         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
3159         struct btrfs_ordered_extent *ordered_extent = NULL;
3160         struct btrfs_workqueue *wq;
3161         btrfs_work_func_t func;
3162
3163         trace_btrfs_writepage_end_io_hook(page, start, end, uptodate);
3164
3165         ClearPagePrivate2(page);
3166         if (!btrfs_dec_test_ordered_pending(inode, &ordered_extent, start,
3167                                             end - start + 1, uptodate))
3168                 return;
3169
3170         if (btrfs_is_free_space_inode(BTRFS_I(inode))) {
3171                 wq = fs_info->endio_freespace_worker;
3172                 func = btrfs_freespace_write_helper;
3173         } else {
3174                 wq = fs_info->endio_write_workers;
3175                 func = btrfs_endio_write_helper;
3176         }
3177
3178         btrfs_init_work(&ordered_extent->work, func, finish_ordered_fn, NULL,
3179                         NULL);
3180         btrfs_queue_work(wq, &ordered_extent->work);
3181 }
3182
3183 static int __readpage_endio_check(struct inode *inode,
3184                                   struct btrfs_io_bio *io_bio,
3185                                   int icsum, struct page *page,
3186                                   int pgoff, u64 start, size_t len)
3187 {
3188         char *kaddr;
3189         u32 csum_expected;
3190         u32 csum = ~(u32)0;
3191
3192         csum_expected = *(((u32 *)io_bio->csum) + icsum);
3193
3194         kaddr = kmap_atomic(page);
3195         csum = btrfs_csum_data(kaddr + pgoff, csum,  len);
3196         btrfs_csum_final(csum, (u8 *)&csum);
3197         if (csum != csum_expected)
3198                 goto zeroit;
3199
3200         kunmap_atomic(kaddr);
3201         return 0;
3202 zeroit:
3203         btrfs_print_data_csum_error(BTRFS_I(inode), start, csum, csum_expected,
3204                                     io_bio->mirror_num);
3205         memset(kaddr + pgoff, 1, len);
3206         flush_dcache_page(page);
3207         kunmap_atomic(kaddr);
3208         return -EIO;
3209 }
3210
3211 /*
3212  * when reads are done, we need to check csums to verify the data is correct
3213  * if there's a match, we allow the bio to finish.  If not, the code in
3214  * extent_io.c will try to find good copies for us.
3215  */
3216 static int btrfs_readpage_end_io_hook(struct btrfs_io_bio *io_bio,
3217                                       u64 phy_offset, struct page *page,
3218                                       u64 start, u64 end, int mirror)
3219 {
3220         size_t offset = start - page_offset(page);
3221         struct inode *inode = page->mapping->host;
3222         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
3223         struct btrfs_root *root = BTRFS_I(inode)->root;
3224
3225         if (PageChecked(page)) {
3226                 ClearPageChecked(page);
3227                 return 0;
3228         }
3229
3230         if (BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM)
3231                 return 0;
3232
3233         if (root->root_key.objectid == BTRFS_DATA_RELOC_TREE_OBJECTID &&
3234             test_range_bit(io_tree, start, end, EXTENT_NODATASUM, 1, NULL)) {
3235                 clear_extent_bits(io_tree, start, end, EXTENT_NODATASUM);
3236                 return 0;
3237         }
3238
3239         phy_offset >>= inode->i_sb->s_blocksize_bits;
3240         return __readpage_endio_check(inode, io_bio, phy_offset, page, offset,
3241                                       start, (size_t)(end - start + 1));
3242 }
3243
3244 /*
3245  * btrfs_add_delayed_iput - perform a delayed iput on @inode
3246  *
3247  * @inode: The inode we want to perform iput on
3248  *
3249  * This function uses the generic vfs_inode::i_count to track whether we should
3250  * just decrement it (in case it's > 1) or if this is the last iput then link
3251  * the inode to the delayed iput machinery. Delayed iputs are processed at
3252  * transaction commit time/superblock commit/cleaner kthread.
3253  */
3254 void btrfs_add_delayed_iput(struct inode *inode)
3255 {
3256         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
3257         struct btrfs_inode *binode = BTRFS_I(inode);
3258
3259         if (atomic_add_unless(&inode->i_count, -1, 1))
3260                 return;
3261
3262         spin_lock(&fs_info->delayed_iput_lock);
3263         ASSERT(list_empty(&binode->delayed_iput));
3264         list_add_tail(&binode->delayed_iput, &fs_info->delayed_iputs);
3265         spin_unlock(&fs_info->delayed_iput_lock);
3266 }
3267
3268 void btrfs_run_delayed_iputs(struct btrfs_fs_info *fs_info)
3269 {
3270
3271         spin_lock(&fs_info->delayed_iput_lock);
3272         while (!list_empty(&fs_info->delayed_iputs)) {
3273                 struct btrfs_inode *inode;
3274
3275                 inode = list_first_entry(&fs_info->delayed_iputs,
3276                                 struct btrfs_inode, delayed_iput);
3277                 list_del_init(&inode->delayed_iput);
3278                 spin_unlock(&fs_info->delayed_iput_lock);
3279                 iput(&inode->vfs_inode);
3280                 spin_lock(&fs_info->delayed_iput_lock);
3281         }
3282         spin_unlock(&fs_info->delayed_iput_lock);
3283 }
3284
3285 /*
3286  * This creates an orphan entry for the given inode in case something goes wrong
3287  * in the middle of an unlink.
3288  */
3289 int btrfs_orphan_add(struct btrfs_trans_handle *trans,
3290                      struct btrfs_inode *inode)
3291 {
3292         int ret;
3293
3294         ret = btrfs_insert_orphan_item(trans, inode->root, btrfs_ino(inode));
3295         if (ret && ret != -EEXIST) {
3296                 btrfs_abort_transaction(trans, ret);
3297                 return ret;
3298         }
3299
3300         return 0;
3301 }
3302
3303 /*
3304  * We have done the delete so we can go ahead and remove the orphan item for
3305  * this particular inode.
3306  */
3307 static int btrfs_orphan_del(struct btrfs_trans_handle *trans,
3308                             struct btrfs_inode *inode)
3309 {
3310         return btrfs_del_orphan_item(trans, inode->root, btrfs_ino(inode));
3311 }
3312
3313 /*
3314  * this cleans up any orphans that may be left on the list from the last use
3315  * of this root.
3316  */
3317 int btrfs_orphan_cleanup(struct btrfs_root *root)
3318 {
3319         struct btrfs_fs_info *fs_info = root->fs_info;
3320         struct btrfs_path *path;
3321         struct extent_buffer *leaf;
3322         struct btrfs_key key, found_key;
3323         struct btrfs_trans_handle *trans;
3324         struct inode *inode;
3325         u64 last_objectid = 0;
3326         int ret = 0, nr_unlink = 0;
3327
3328         if (cmpxchg(&root->orphan_cleanup_state, 0, ORPHAN_CLEANUP_STARTED))
3329                 return 0;
3330
3331         path = btrfs_alloc_path();
3332         if (!path) {
3333                 ret = -ENOMEM;
3334                 goto out;
3335         }
3336         path->reada = READA_BACK;
3337
3338         key.objectid = BTRFS_ORPHAN_OBJECTID;
3339         key.type = BTRFS_ORPHAN_ITEM_KEY;
3340         key.offset = (u64)-1;
3341
3342         while (1) {
3343                 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
3344                 if (ret < 0)
3345                         goto out;
3346
3347                 /*
3348                  * if ret == 0 means we found what we were searching for, which
3349                  * is weird, but possible, so only screw with path if we didn't
3350                  * find the key and see if we have stuff that matches
3351                  */
3352                 if (ret > 0) {
3353                         ret = 0;
3354                         if (path->slots[0] == 0)
3355                                 break;
3356                         path->slots[0]--;
3357                 }
3358
3359                 /* pull out the item */
3360                 leaf = path->nodes[0];
3361                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
3362
3363                 /* make sure the item matches what we want */
3364                 if (found_key.objectid != BTRFS_ORPHAN_OBJECTID)
3365                         break;
3366                 if (found_key.type != BTRFS_ORPHAN_ITEM_KEY)
3367                         break;
3368
3369                 /* release the path since we're done with it */
3370                 btrfs_release_path(path);
3371
3372                 /*
3373                  * this is where we are basically btrfs_lookup, without the
3374                  * crossing root thing.  we store the inode number in the
3375                  * offset of the orphan item.
3376                  */
3377
3378                 if (found_key.offset == last_objectid) {
3379                         btrfs_err(fs_info,
3380                                   "Error removing orphan entry, stopping orphan cleanup");
3381                         ret = -EINVAL;
3382                         goto out;
3383                 }
3384
3385                 last_objectid = found_key.offset;
3386
3387                 found_key.objectid = found_key.offset;
3388                 found_key.type = BTRFS_INODE_ITEM_KEY;
3389                 found_key.offset = 0;
3390                 inode = btrfs_iget(fs_info->sb, &found_key, root, NULL);
3391                 ret = PTR_ERR_OR_ZERO(inode);
3392                 if (ret && ret != -ENOENT)
3393                         goto out;
3394
3395                 if (ret == -ENOENT && root == fs_info->tree_root) {
3396                         struct btrfs_root *dead_root;
3397                         struct btrfs_fs_info *fs_info = root->fs_info;
3398                         int is_dead_root = 0;
3399
3400                         /*
3401                          * this is an orphan in the tree root. Currently these
3402                          * could come from 2 sources:
3403                          *  a) a snapshot deletion in progress
3404                          *  b) a free space cache inode
3405                          * We need to distinguish those two, as the snapshot
3406                          * orphan must not get deleted.
3407                          * find_dead_roots already ran before us, so if this
3408                          * is a snapshot deletion, we should find the root
3409                          * in the dead_roots list
3410                          */
3411                         spin_lock(&fs_info->trans_lock);
3412                         list_for_each_entry(dead_root, &fs_info->dead_roots,
3413                                             root_list) {
3414                                 if (dead_root->root_key.objectid ==
3415                                     found_key.objectid) {
3416                                         is_dead_root = 1;
3417                                         break;
3418                                 }
3419                         }
3420                         spin_unlock(&fs_info->trans_lock);
3421                         if (is_dead_root) {
3422                                 /* prevent this orphan from being found again */
3423                                 key.offset = found_key.objectid - 1;
3424                                 continue;
3425                         }
3426
3427                 }
3428
3429                 /*
3430                  * If we have an inode with links, there are a couple of
3431                  * possibilities. Old kernels (before v3.12) used to create an
3432                  * orphan item for truncate indicating that there were possibly
3433                  * extent items past i_size that needed to be deleted. In v3.12,
3434                  * truncate was changed to update i_size in sync with the extent
3435                  * items, but the (useless) orphan item was still created. Since
3436                  * v4.18, we don't create the orphan item for truncate at all.
3437                  *
3438                  * So, this item could mean that we need to do a truncate, but
3439                  * only if this filesystem was last used on a pre-v3.12 kernel
3440                  * and was not cleanly unmounted. The odds of that are quite
3441                  * slim, and it's a pain to do the truncate now, so just delete
3442                  * the orphan item.
3443                  *
3444                  * It's also possible that this orphan item was supposed to be
3445                  * deleted but wasn't. The inode number may have been reused,
3446                  * but either way, we can delete the orphan item.
3447                  */
3448                 if (ret == -ENOENT || inode->i_nlink) {
3449                         if (!ret)
3450                                 iput(inode);
3451                         trans = btrfs_start_transaction(root, 1);
3452                         if (IS_ERR(trans)) {
3453                                 ret = PTR_ERR(trans);
3454                                 goto out;
3455                         }
3456                         btrfs_debug(fs_info, "auto deleting %Lu",
3457                                     found_key.objectid);
3458                         ret = btrfs_del_orphan_item(trans, root,
3459                                                     found_key.objectid);
3460                         btrfs_end_transaction(trans);
3461                         if (ret)
3462                                 goto out;
3463                         continue;
3464                 }
3465
3466                 nr_unlink++;
3467
3468                 /* this will do delete_inode and everything for us */
3469                 iput(inode);
3470         }
3471         /* release the path since we're done with it */
3472         btrfs_release_path(path);
3473
3474         root->orphan_cleanup_state = ORPHAN_CLEANUP_DONE;
3475
3476         if (test_bit(BTRFS_ROOT_ORPHAN_ITEM_INSERTED, &root->state)) {
3477                 trans = btrfs_join_transaction(root);
3478                 if (!IS_ERR(trans))
3479                         btrfs_end_transaction(trans);
3480         }
3481
3482         if (nr_unlink)
3483                 btrfs_debug(fs_info, "unlinked %d orphans", nr_unlink);
3484
3485 out:
3486         if (ret)
3487                 btrfs_err(fs_info, "could not do orphan cleanup %d", ret);
3488         btrfs_free_path(path);
3489         return ret;
3490 }
3491
3492 /*
3493  * very simple check to peek ahead in the leaf looking for xattrs.  If we
3494  * don't find any xattrs, we know there can't be any acls.
3495  *
3496  * slot is the slot the inode is in, objectid is the objectid of the inode
3497  */
3498 static noinline int acls_after_inode_item(struct extent_buffer *leaf,
3499                                           int slot, u64 objectid,
3500                                           int *first_xattr_slot)
3501 {
3502         u32 nritems = btrfs_header_nritems(leaf);
3503         struct btrfs_key found_key;
3504         static u64 xattr_access = 0;
3505         static u64 xattr_default = 0;
3506         int scanned = 0;
3507
3508         if (!xattr_access) {
3509                 xattr_access = btrfs_name_hash(XATTR_NAME_POSIX_ACL_ACCESS,
3510                                         strlen(XATTR_NAME_POSIX_ACL_ACCESS));
3511                 xattr_default = btrfs_name_hash(XATTR_NAME_POSIX_ACL_DEFAULT,
3512                                         strlen(XATTR_NAME_POSIX_ACL_DEFAULT));
3513         }
3514
3515         slot++;
3516         *first_xattr_slot = -1;
3517         while (slot < nritems) {
3518                 btrfs_item_key_to_cpu(leaf, &found_key, slot);
3519
3520                 /* we found a different objectid, there must not be acls */
3521                 if (found_key.objectid != objectid)
3522                         return 0;
3523
3524                 /* we found an xattr, assume we've got an acl */
3525                 if (found_key.type == BTRFS_XATTR_ITEM_KEY) {
3526                         if (*first_xattr_slot == -1)
3527                                 *first_xattr_slot = slot;
3528                         if (found_key.offset == xattr_access ||
3529                             found_key.offset == xattr_default)
3530                                 return 1;
3531                 }
3532
3533                 /*
3534                  * we found a key greater than an xattr key, there can't
3535                  * be any acls later on
3536                  */
3537                 if (found_key.type > BTRFS_XATTR_ITEM_KEY)
3538                         return 0;
3539
3540                 slot++;
3541                 scanned++;
3542
3543                 /*
3544                  * it goes inode, inode backrefs, xattrs, extents,
3545                  * so if there are a ton of hard links to an inode there can
3546                  * be a lot of backrefs.  Don't waste time searching too hard,
3547                  * this is just an optimization
3548                  */
3549                 if (scanned >= 8)
3550                         break;
3551         }
3552         /* we hit the end of the leaf before we found an xattr or
3553          * something larger than an xattr.  We have to assume the inode
3554          * has acls
3555          */
3556         if (*first_xattr_slot == -1)
3557                 *first_xattr_slot = slot;
3558         return 1;
3559 }
3560
3561 /*
3562  * read an inode from the btree into the in-memory inode
3563  */
3564 static int btrfs_read_locked_inode(struct inode *inode)
3565 {
3566         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
3567         struct btrfs_path *path;
3568         struct extent_buffer *leaf;
3569         struct btrfs_inode_item *inode_item;
3570         struct btrfs_root *root = BTRFS_I(inode)->root;
3571         struct btrfs_key location;
3572         unsigned long ptr;
3573         int maybe_acls;
3574         u32 rdev;
3575         int ret;
3576         bool filled = false;
3577         int first_xattr_slot;
3578
3579         ret = btrfs_fill_inode(inode, &rdev);
3580         if (!ret)
3581                 filled = true;
3582
3583         path = btrfs_alloc_path();
3584         if (!path)
3585                 return -ENOMEM;
3586
3587         memcpy(&location, &BTRFS_I(inode)->location, sizeof(location));
3588
3589         ret = btrfs_lookup_inode(NULL, root, path, &location, 0);
3590         if (ret) {
3591                 btrfs_free_path(path);
3592                 return ret;
3593         }
3594
3595         leaf = path->nodes[0];
3596
3597         if (filled)
3598                 goto cache_index;
3599
3600         inode_item = btrfs_item_ptr(leaf, path->slots[0],
3601                                     struct btrfs_inode_item);
3602         inode->i_mode = btrfs_inode_mode(leaf, inode_item);
3603         set_nlink(inode, btrfs_inode_nlink(leaf, inode_item));
3604         i_uid_write(inode, btrfs_inode_uid(leaf, inode_item));
3605         i_gid_write(inode, btrfs_inode_gid(leaf, inode_item));
3606         btrfs_i_size_write(BTRFS_I(inode), btrfs_inode_size(leaf, inode_item));
3607
3608         inode->i_atime.tv_sec = btrfs_timespec_sec(leaf, &inode_item->atime);
3609         inode->i_atime.tv_nsec = btrfs_timespec_nsec(leaf, &inode_item->atime);
3610
3611         inode->i_mtime.tv_sec = btrfs_timespec_sec(leaf, &inode_item->mtime);
3612         inode->i_mtime.tv_nsec = btrfs_timespec_nsec(leaf, &inode_item->mtime);
3613
3614         inode->i_ctime.tv_sec = btrfs_timespec_sec(leaf, &inode_item->ctime);
3615         inode->i_ctime.tv_nsec = btrfs_timespec_nsec(leaf, &inode_item->ctime);
3616
3617         BTRFS_I(inode)->i_otime.tv_sec =
3618                 btrfs_timespec_sec(leaf, &inode_item->otime);
3619         BTRFS_I(inode)->i_otime.tv_nsec =
3620                 btrfs_timespec_nsec(leaf, &inode_item->otime);
3621
3622         inode_set_bytes(inode, btrfs_inode_nbytes(leaf, inode_item));
3623         BTRFS_I(inode)->generation = btrfs_inode_generation(leaf, inode_item);
3624         BTRFS_I(inode)->last_trans = btrfs_inode_transid(leaf, inode_item);
3625
3626         inode_set_iversion_queried(inode,
3627                                    btrfs_inode_sequence(leaf, inode_item));
3628         inode->i_generation = BTRFS_I(inode)->generation;
3629         inode->i_rdev = 0;
3630         rdev = btrfs_inode_rdev(leaf, inode_item);
3631
3632         BTRFS_I(inode)->index_cnt = (u64)-1;
3633         BTRFS_I(inode)->flags = btrfs_inode_flags(leaf, inode_item);
3634
3635 cache_index:
3636         /*
3637          * If we were modified in the current generation and evicted from memory
3638          * and then re-read we need to do a full sync since we don't have any
3639          * idea about which extents were modified before we were evicted from
3640          * cache.
3641          *
3642          * This is required for both inode re-read from disk and delayed inode
3643          * in delayed_nodes_tree.
3644          */
3645         if (BTRFS_I(inode)->last_trans == fs_info->generation)
3646                 set_bit(BTRFS_INODE_NEEDS_FULL_SYNC,
3647                         &BTRFS_I(inode)->runtime_flags);
3648
3649         /*
3650          * We don't persist the id of the transaction where an unlink operation
3651          * against the inode was last made. So here we assume the inode might
3652          * have been evicted, and therefore the exact value of last_unlink_trans
3653          * lost, and set it to last_trans to avoid metadata inconsistencies
3654          * between the inode and its parent if the inode is fsync'ed and the log
3655          * replayed. For example, in the scenario:
3656          *
3657          * touch mydir/foo
3658          * ln mydir/foo mydir/bar
3659          * sync
3660          * unlink mydir/bar
3661          * echo 2 > /proc/sys/vm/drop_caches   # evicts inode
3662          * xfs_io -c fsync mydir/foo
3663          * <power failure>
3664          * mount fs, triggers fsync log replay
3665          *
3666          * We must make sure that when we fsync our inode foo we also log its
3667          * parent inode, otherwise after log replay the parent still has the
3668          * dentry with the "bar" name but our inode foo has a link count of 1
3669          * and doesn't have an inode ref with the name "bar" anymore.
3670          *
3671          * Setting last_unlink_trans to last_trans is a pessimistic approach,
3672          * but it guarantees correctness at the expense of occasional full
3673          * transaction commits on fsync if our inode is a directory, or if our
3674          * inode is not a directory, logging its parent unnecessarily.
3675          */
3676         BTRFS_I(inode)->last_unlink_trans = BTRFS_I(inode)->last_trans;
3677
3678         path->slots[0]++;
3679         if (inode->i_nlink != 1 ||
3680             path->slots[0] >= btrfs_header_nritems(leaf))
3681                 goto cache_acl;
3682
3683         btrfs_item_key_to_cpu(leaf, &location, path->slots[0]);
3684         if (location.objectid != btrfs_ino(BTRFS_I(inode)))
3685                 goto cache_acl;
3686
3687         ptr = btrfs_item_ptr_offset(leaf, path->slots[0]);
3688         if (location.type == BTRFS_INODE_REF_KEY) {
3689                 struct btrfs_inode_ref *ref;
3690
3691                 ref = (struct btrfs_inode_ref *)ptr;
3692                 BTRFS_I(inode)->dir_index = btrfs_inode_ref_index(leaf, ref);
3693         } else if (location.type == BTRFS_INODE_EXTREF_KEY) {
3694                 struct btrfs_inode_extref *extref;
3695
3696                 extref = (struct btrfs_inode_extref *)ptr;
3697                 BTRFS_I(inode)->dir_index = btrfs_inode_extref_index(leaf,
3698                                                                      extref);
3699         }
3700 cache_acl:
3701         /*
3702          * try to precache a NULL acl entry for files that don't have
3703          * any xattrs or acls
3704          */
3705         maybe_acls = acls_after_inode_item(leaf, path->slots[0],
3706                         btrfs_ino(BTRFS_I(inode)), &first_xattr_slot);
3707         if (first_xattr_slot != -1) {
3708                 path->slots[0] = first_xattr_slot;
3709                 ret = btrfs_load_inode_props(inode, path);
3710                 if (ret)
3711                         btrfs_err(fs_info,
3712                                   "error loading props for ino %llu (root %llu): %d",
3713                                   btrfs_ino(BTRFS_I(inode)),
3714                                   root->root_key.objectid, ret);
3715         }
3716         btrfs_free_path(path);
3717
3718         if (!maybe_acls)
3719                 cache_no_acl(inode);
3720
3721         switch (inode->i_mode & S_IFMT) {
3722         case S_IFREG:
3723                 inode->i_mapping->a_ops = &btrfs_aops;
3724                 BTRFS_I(inode)->io_tree.ops = &btrfs_extent_io_ops;
3725                 inode->i_fop = &btrfs_file_operations;
3726                 inode->i_op = &btrfs_file_inode_operations;
3727                 break;
3728         case S_IFDIR:
3729                 inode->i_fop = &btrfs_dir_file_operations;
3730                 inode->i_op = &btrfs_dir_inode_operations;
3731                 break;
3732         case S_IFLNK:
3733                 inode->i_op = &btrfs_symlink_inode_operations;
3734                 inode_nohighmem(inode);
3735                 inode->i_mapping->a_ops = &btrfs_aops;
3736                 break;
3737         default:
3738                 inode->i_op = &btrfs_special_inode_operations;
3739                 init_special_inode(inode, inode->i_mode, rdev);
3740                 break;
3741         }
3742
3743         btrfs_sync_inode_flags_to_i_flags(inode);
3744         return 0;
3745 }
3746
3747 /*
3748  * given a leaf and an inode, copy the inode fields into the leaf
3749  */
3750 static void fill_inode_item(struct btrfs_trans_handle *trans,
3751                             struct extent_buffer *leaf,
3752                             struct btrfs_inode_item *item,
3753                             struct inode *inode)
3754 {
3755         struct btrfs_map_token token;
3756
3757         btrfs_init_map_token(&token);
3758
3759         btrfs_set_token_inode_uid(leaf, item, i_uid_read(inode), &token);
3760         btrfs_set_token_inode_gid(leaf, item, i_gid_read(inode), &token);
3761         btrfs_set_token_inode_size(leaf, item, BTRFS_I(inode)->disk_i_size,
3762                                    &token);
3763         btrfs_set_token_inode_mode(leaf, item, inode->i_mode, &token);
3764         btrfs_set_token_inode_nlink(leaf, item, inode->i_nlink, &token);
3765
3766         btrfs_set_token_timespec_sec(leaf, &item->atime,
3767                                      inode->i_atime.tv_sec, &token);
3768         btrfs_set_token_timespec_nsec(leaf, &item->atime,
3769                                       inode->i_atime.tv_nsec, &token);
3770
3771         btrfs_set_token_timespec_sec(leaf, &item->mtime,
3772                                      inode->i_mtime.tv_sec, &token);
3773         btrfs_set_token_timespec_nsec(leaf, &item->mtime,
3774                                       inode->i_mtime.tv_nsec, &token);
3775
3776         btrfs_set_token_timespec_sec(leaf, &item->ctime,
3777                                      inode->i_ctime.tv_sec, &token);
3778         btrfs_set_token_timespec_nsec(leaf, &item->ctime,
3779                                       inode->i_ctime.tv_nsec, &token);
3780
3781         btrfs_set_token_timespec_sec(leaf, &item->otime,
3782                                      BTRFS_I(inode)->i_otime.tv_sec, &token);
3783         btrfs_set_token_timespec_nsec(leaf, &item->otime,
3784                                       BTRFS_I(inode)->i_otime.tv_nsec, &token);
3785
3786         btrfs_set_token_inode_nbytes(leaf, item, inode_get_bytes(inode),
3787                                      &token);
3788         btrfs_set_token_inode_generation(leaf, item, BTRFS_I(inode)->generation,
3789                                          &token);
3790         btrfs_set_token_inode_sequence(leaf, item, inode_peek_iversion(inode),
3791                                        &token);
3792         btrfs_set_token_inode_transid(leaf, item, trans->transid, &token);
3793         btrfs_set_token_inode_rdev(leaf, item, inode->i_rdev, &token);
3794         btrfs_set_token_inode_flags(leaf, item, BTRFS_I(inode)->flags, &token);
3795         btrfs_set_token_inode_block_group(leaf, item, 0, &token);
3796 }
3797
3798 /*
3799  * copy everything in the in-memory inode into the btree.
3800  */
3801 static noinline int btrfs_update_inode_item(struct btrfs_trans_handle *trans,
3802                                 struct btrfs_root *root, struct inode *inode)
3803 {
3804         struct btrfs_inode_item *inode_item;
3805         struct btrfs_path *path;
3806         struct extent_buffer *leaf;
3807         int ret;
3808
3809         path = btrfs_alloc_path();
3810         if (!path)
3811                 return -ENOMEM;
3812
3813         path->leave_spinning = 1;
3814         ret = btrfs_lookup_inode(trans, root, path, &BTRFS_I(inode)->location,
3815                                  1);
3816         if (ret) {
3817                 if (ret > 0)
3818                         ret = -ENOENT;
3819                 goto failed;
3820         }
3821
3822         leaf = path->nodes[0];
3823         inode_item = btrfs_item_ptr(leaf, path->slots[0],
3824                                     struct btrfs_inode_item);
3825
3826         fill_inode_item(trans, leaf, inode_item, inode);
3827         btrfs_mark_buffer_dirty(leaf);
3828         btrfs_set_inode_last_trans(trans, inode);
3829         ret = 0;
3830 failed:
3831         btrfs_free_path(path);
3832         return ret;
3833 }
3834
3835 /*
3836  * copy everything in the in-memory inode into the btree.
3837  */
3838 noinline int btrfs_update_inode(struct btrfs_trans_handle *trans,
3839                                 struct btrfs_root *root, struct inode *inode)
3840 {
3841         struct btrfs_fs_info *fs_info = root->fs_info;
3842         int ret;
3843
3844         /*
3845          * If the inode is a free space inode, we can deadlock during commit
3846          * if we put it into the delayed code.
3847          *
3848          * The data relocation inode should also be directly updated
3849          * without delay
3850          */
3851         if (!btrfs_is_free_space_inode(BTRFS_I(inode))
3852             && root->root_key.objectid != BTRFS_DATA_RELOC_TREE_OBJECTID
3853             && !test_bit(BTRFS_FS_LOG_RECOVERING, &fs_info->flags)) {
3854                 btrfs_update_root_times(trans, root);
3855
3856                 ret = btrfs_delayed_update_inode(trans, root, inode);
3857                 if (!ret)
3858                         btrfs_set_inode_last_trans(trans, inode);
3859                 return ret;
3860         }
3861
3862         return btrfs_update_inode_item(trans, root, inode);
3863 }
3864
3865 noinline int btrfs_update_inode_fallback(struct btrfs_trans_handle *trans,
3866                                          struct btrfs_root *root,
3867                                          struct inode *inode)
3868 {
3869         int ret;
3870
3871         ret = btrfs_update_inode(trans, root, inode);
3872         if (ret == -ENOSPC)
3873                 return btrfs_update_inode_item(trans, root, inode);
3874         return ret;
3875 }
3876
3877 /*
3878  * unlink helper that gets used here in inode.c and in the tree logging
3879  * recovery code.  It remove a link in a directory with a given name, and
3880  * also drops the back refs in the inode to the directory
3881  */
3882 static int __btrfs_unlink_inode(struct btrfs_trans_handle *trans,
3883                                 struct btrfs_root *root,
3884                                 struct btrfs_inode *dir,
3885                                 struct btrfs_inode *inode,
3886                                 const char *name, int name_len)
3887 {
3888         struct btrfs_fs_info *fs_info = root->fs_info;
3889         struct btrfs_path *path;
3890         int ret = 0;
3891         struct extent_buffer *leaf;
3892         struct btrfs_dir_item *di;
3893         struct btrfs_key key;
3894         u64 index;
3895         u64 ino = btrfs_ino(inode);
3896         u64 dir_ino = btrfs_ino(dir);
3897
3898         path = btrfs_alloc_path();
3899         if (!path) {
3900                 ret = -ENOMEM;
3901                 goto out;
3902         }
3903
3904         path->leave_spinning = 1;
3905         di = btrfs_lookup_dir_item(trans, root, path, dir_ino,
3906                                     name, name_len, -1);
3907         if (IS_ERR_OR_NULL(di)) {
3908                 ret = di ? PTR_ERR(di) : -ENOENT;
3909                 goto err;
3910         }
3911         leaf = path->nodes[0];
3912         btrfs_dir_item_key_to_cpu(leaf, di, &key);
3913         ret = btrfs_delete_one_dir_name(trans, root, path, di);
3914         if (ret)
3915                 goto err;
3916         btrfs_release_path(path);
3917
3918         /*
3919          * If we don't have dir index, we have to get it by looking up
3920          * the inode ref, since we get the inode ref, remove it directly,
3921          * it is unnecessary to do delayed deletion.
3922          *
3923          * But if we have dir index, needn't search inode ref to get it.
3924          * Since the inode ref is close to the inode item, it is better
3925          * that we delay to delete it, and just do this deletion when
3926          * we update the inode item.
3927          */
3928         if (inode->dir_index) {
3929                 ret = btrfs_delayed_delete_inode_ref(inode);
3930                 if (!ret) {
3931                         index = inode->dir_index;
3932                         goto skip_backref;
3933                 }
3934         }
3935
3936         ret = btrfs_del_inode_ref(trans, root, name, name_len, ino,
3937                                   dir_ino, &index);
3938         if (ret) {
3939                 btrfs_info(fs_info,
3940                         "failed to delete reference to %.*s, inode %llu parent %llu",
3941                         name_len, name, ino, dir_ino);
3942                 btrfs_abort_transaction(trans, ret);
3943                 goto err;
3944         }
3945 skip_backref:
3946         ret = btrfs_delete_delayed_dir_index(trans, dir, index);
3947         if (ret) {
3948                 btrfs_abort_transaction(trans, ret);
3949                 goto err;
3950         }
3951
3952         ret = btrfs_del_inode_ref_in_log(trans, root, name, name_len, inode,
3953                         dir_ino);
3954         if (ret != 0 && ret != -ENOENT) {
3955                 btrfs_abort_transaction(trans, ret);
3956                 goto err;
3957         }
3958
3959         ret = btrfs_del_dir_entries_in_log(trans, root, name, name_len, dir,
3960                         index);
3961         if (ret == -ENOENT)
3962                 ret = 0;
3963         else if (ret)
3964                 btrfs_abort_transaction(trans, ret);
3965 err:
3966         btrfs_free_path(path);
3967         if (ret)
3968                 goto out;
3969
3970         btrfs_i_size_write(dir, dir->vfs_inode.i_size - name_len * 2);
3971         inode_inc_iversion(&inode->vfs_inode);
3972         inode_inc_iversion(&dir->vfs_inode);
3973         inode->vfs_inode.i_ctime = dir->vfs_inode.i_mtime =
3974                 dir->vfs_inode.i_ctime = current_time(&inode->vfs_inode);
3975         ret = btrfs_update_inode(trans, root, &dir->vfs_inode);
3976 out:
3977         return ret;
3978 }
3979
3980 int btrfs_unlink_inode(struct btrfs_trans_handle *trans,
3981                        struct btrfs_root *root,
3982                        struct btrfs_inode *dir, struct btrfs_inode *inode,
3983                        const char *name, int name_len)
3984 {
3985         int ret;
3986         ret = __btrfs_unlink_inode(trans, root, dir, inode, name, name_len);
3987         if (!ret) {
3988                 drop_nlink(&inode->vfs_inode);
3989                 ret = btrfs_update_inode(trans, root, &inode->vfs_inode);
3990         }
3991         return ret;
3992 }
3993
3994 /*
3995  * helper to start transaction for unlink and rmdir.
3996  *
3997  * unlink and rmdir are special in btrfs, they do not always free space, so
3998  * if we cannot make our reservations the normal way try and see if there is
3999  * plenty of slack room in the global reserve to migrate, otherwise we cannot
4000  * allow the unlink to occur.
4001  */
4002 static struct btrfs_trans_handle *__unlink_start_trans(struct inode *dir)
4003 {
4004         struct btrfs_root *root = BTRFS_I(dir)->root;
4005
4006         /*
4007          * 1 for the possible orphan item
4008          * 1 for the dir item
4009          * 1 for the dir index
4010          * 1 for the inode ref
4011          * 1 for the inode
4012          */
4013         return btrfs_start_transaction_fallback_global_rsv(root, 5, 5);
4014 }
4015
4016 static int btrfs_unlink(struct inode *dir, struct dentry *dentry)
4017 {
4018         struct btrfs_root *root = BTRFS_I(dir)->root;
4019         struct btrfs_trans_handle *trans;
4020         struct inode *inode = d_inode(dentry);
4021         int ret;
4022
4023         trans = __unlink_start_trans(dir);
4024         if (IS_ERR(trans))
4025                 return PTR_ERR(trans);
4026
4027         btrfs_record_unlink_dir(trans, BTRFS_I(dir), BTRFS_I(d_inode(dentry)),
4028                         0);
4029
4030         ret = btrfs_unlink_inode(trans, root, BTRFS_I(dir),
4031                         BTRFS_I(d_inode(dentry)), dentry->d_name.name,
4032                         dentry->d_name.len);
4033         if (ret)
4034                 goto out;
4035
4036         if (inode->i_nlink == 0) {
4037                 ret = btrfs_orphan_add(trans, BTRFS_I(inode));
4038                 if (ret)
4039                         goto out;
4040         }
4041
4042 out:
4043         btrfs_end_transaction(trans);
4044         btrfs_btree_balance_dirty(root->fs_info);
4045         return ret;
4046 }
4047
4048 static int btrfs_unlink_subvol(struct btrfs_trans_handle *trans,
4049                                struct inode *dir, u64 objectid,
4050                                const char *name, int name_len)
4051 {
4052         struct btrfs_root *root = BTRFS_I(dir)->root;
4053         struct btrfs_path *path;
4054         struct extent_buffer *leaf;
4055         struct btrfs_dir_item *di;
4056         struct btrfs_key key;
4057         u64 index;
4058         int ret;
4059         u64 dir_ino = btrfs_ino(BTRFS_I(dir));
4060
4061         path = btrfs_alloc_path();
4062         if (!path)
4063                 return -ENOMEM;
4064
4065         di = btrfs_lookup_dir_item(trans, root, path, dir_ino,
4066                                    name, name_len, -1);
4067         if (IS_ERR_OR_NULL(di)) {
4068                 ret = di ? PTR_ERR(di) : -ENOENT;
4069                 goto out;
4070         }
4071
4072         leaf = path->nodes[0];
4073         btrfs_dir_item_key_to_cpu(leaf, di, &key);
4074         WARN_ON(key.type != BTRFS_ROOT_ITEM_KEY || key.objectid != objectid);
4075         ret = btrfs_delete_one_dir_name(trans, root, path, di);
4076         if (ret) {
4077                 btrfs_abort_transaction(trans, ret);
4078                 goto out;
4079         }
4080         btrfs_release_path(path);
4081
4082         ret = btrfs_del_root_ref(trans, objectid, root->root_key.objectid,
4083                                  dir_ino, &index, name, name_len);
4084         if (ret < 0) {
4085                 if (ret != -ENOENT) {
4086                         btrfs_abort_transaction(trans, ret);
4087                         goto out;
4088                 }
4089                 di = btrfs_search_dir_index_item(root, path, dir_ino,
4090                                                  name, name_len);
4091                 if (IS_ERR_OR_NULL(di)) {
4092                         if (!di)
4093                                 ret = -ENOENT;
4094                         else
4095                                 ret = PTR_ERR(di);
4096                         btrfs_abort_transaction(trans, ret);
4097                         goto out;
4098                 }
4099
4100                 leaf = path->nodes[0];
4101                 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
4102                 index = key.offset;
4103         }
4104         btrfs_release_path(path);
4105
4106         ret = btrfs_delete_delayed_dir_index(trans, BTRFS_I(dir), index);
4107         if (ret) {
4108                 btrfs_abort_transaction(trans, ret);
4109                 goto out;
4110         }
4111
4112         btrfs_i_size_write(BTRFS_I(dir), dir->i_size - name_len * 2);
4113         inode_inc_iversion(dir);
4114         dir->i_mtime = dir->i_ctime = current_time(dir);
4115         ret = btrfs_update_inode_fallback(trans, root, dir);
4116         if (ret)
4117                 btrfs_abort_transaction(trans, ret);
4118 out:
4119         btrfs_free_path(path);
4120         return ret;
4121 }
4122
4123 /*
4124  * Helper to check if the subvolume references other subvolumes or if it's
4125  * default.
4126  */
4127 static noinline int may_destroy_subvol(struct btrfs_root *root)
4128 {
4129         struct btrfs_fs_info *fs_info = root->fs_info;
4130         struct btrfs_path *path;
4131         struct btrfs_dir_item *di;
4132         struct btrfs_key key;
4133         u64 dir_id;
4134         int ret;
4135
4136         path = btrfs_alloc_path();
4137         if (!path)
4138                 return -ENOMEM;
4139
4140         /* Make sure this root isn't set as the default subvol */
4141         dir_id = btrfs_super_root_dir(fs_info->super_copy);
4142         di = btrfs_lookup_dir_item(NULL, fs_info->tree_root, path,
4143                                    dir_id, "default", 7, 0);
4144         if (di && !IS_ERR(di)) {
4145                 btrfs_dir_item_key_to_cpu(path->nodes[0], di, &key);
4146                 if (key.objectid == root->root_key.objectid) {
4147                         ret = -EPERM;
4148                         btrfs_err(fs_info,
4149                                   "deleting default subvolume %llu is not allowed",
4150                                   key.objectid);
4151                         goto out;
4152                 }
4153                 btrfs_release_path(path);
4154         }
4155
4156         key.objectid = root->root_key.objectid;
4157         key.type = BTRFS_ROOT_REF_KEY;
4158         key.offset = (u64)-1;
4159
4160         ret = btrfs_search_slot(NULL, fs_info->tree_root, &key, path, 0, 0);
4161         if (ret < 0)
4162                 goto out;
4163         BUG_ON(ret == 0);
4164
4165         ret = 0;
4166         if (path->slots[0] > 0) {
4167                 path->slots[0]--;
4168                 btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
4169                 if (key.objectid == root->root_key.objectid &&
4170                     key.type == BTRFS_ROOT_REF_KEY)
4171                         ret = -ENOTEMPTY;
4172         }
4173 out:
4174         btrfs_free_path(path);
4175         return ret;
4176 }
4177
4178 /* Delete all dentries for inodes belonging to the root */
4179 static void btrfs_prune_dentries(struct btrfs_root *root)
4180 {
4181         struct btrfs_fs_info *fs_info = root->fs_info;
4182         struct rb_node *node;
4183         struct rb_node *prev;
4184         struct btrfs_inode *entry;
4185         struct inode *inode;
4186         u64 objectid = 0;
4187
4188         if (!test_bit(BTRFS_FS_STATE_ERROR, &fs_info->fs_state))
4189                 WARN_ON(btrfs_root_refs(&root->root_item) != 0);
4190
4191         spin_lock(&root->inode_lock);
4192 again:
4193         node = root->inode_tree.rb_node;
4194         prev = NULL;
4195         while (node) {
4196                 prev = node;
4197                 entry = rb_entry(node, struct btrfs_inode, rb_node);
4198
4199                 if (objectid < btrfs_ino(entry))
4200                         node = node->rb_left;
4201                 else if (objectid > btrfs_ino(entry))
4202                         node = node->rb_right;
4203                 else
4204                         break;
4205         }
4206         if (!node) {
4207                 while (prev) {
4208                         entry = rb_entry(prev, struct btrfs_inode, rb_node);
4209                         if (objectid <= btrfs_ino(entry)) {
4210                                 node = prev;
4211                                 break;
4212                         }
4213                         prev = rb_next(prev);
4214                 }
4215         }
4216         while (node) {
4217                 entry = rb_entry(node, struct btrfs_inode, rb_node);
4218                 objectid = btrfs_ino(entry) + 1;
4219                 inode = igrab(&entry->vfs_inode);
4220                 if (inode) {
4221                         spin_unlock(&root->inode_lock);
4222                         if (atomic_read(&inode->i_count) > 1)
4223                                 d_prune_aliases(inode);
4224                         /*
4225                          * btrfs_drop_inode will have it removed from the inode
4226                          * cache when its usage count hits zero.
4227                          */
4228                         iput(inode);
4229                         cond_resched();
4230                         spin_lock(&root->inode_lock);
4231                         goto again;
4232                 }
4233
4234                 if (cond_resched_lock(&root->inode_lock))
4235                         goto again;
4236
4237                 node = rb_next(node);
4238         }
4239         spin_unlock(&root->inode_lock);
4240 }
4241
4242 int btrfs_delete_subvolume(struct inode *dir, struct dentry *dentry)
4243 {
4244         struct btrfs_fs_info *fs_info = btrfs_sb(dentry->d_sb);
4245         struct btrfs_root *root = BTRFS_I(dir)->root;
4246         struct inode *inode = d_inode(dentry);
4247         struct btrfs_root *dest = BTRFS_I(inode)->root;
4248         struct btrfs_trans_handle *trans;
4249         struct btrfs_block_rsv block_rsv;
4250         u64 root_flags;
4251         int ret;
4252         int err;
4253
4254         /*
4255          * Don't allow to delete a subvolume with send in progress. This is
4256          * inside the inode lock so the error handling that has to drop the bit
4257          * again is not run concurrently.
4258          */
4259         spin_lock(&dest->root_item_lock);
4260         if (dest->send_in_progress) {
4261                 spin_unlock(&dest->root_item_lock);
4262                 btrfs_warn(fs_info,
4263                            "attempt to delete subvolume %llu during send",
4264                            dest->root_key.objectid);
4265                 return -EPERM;
4266         }
4267         root_flags = btrfs_root_flags(&dest->root_item);
4268         btrfs_set_root_flags(&dest->root_item,
4269                              root_flags | BTRFS_ROOT_SUBVOL_DEAD);
4270         spin_unlock(&dest->root_item_lock);
4271
4272         down_write(&fs_info->subvol_sem);
4273
4274         err = may_destroy_subvol(dest);
4275         if (err)
4276                 goto out_up_write;
4277
4278         btrfs_init_block_rsv(&block_rsv, BTRFS_BLOCK_RSV_TEMP);
4279         /*
4280          * One for dir inode,
4281          * two for dir entries,
4282          * two for root ref/backref.
4283          */
4284         err = btrfs_subvolume_reserve_metadata(root, &block_rsv, 5, true);
4285         if (err)
4286                 goto out_up_write;
4287
4288         trans = btrfs_start_transaction(root, 0);
4289         if (IS_ERR(trans)) {
4290                 err = PTR_ERR(trans);
4291                 goto out_release;
4292         }
4293         trans->block_rsv = &block_rsv;
4294         trans->bytes_reserved = block_rsv.size;
4295
4296         btrfs_record_snapshot_destroy(trans, BTRFS_I(dir));
4297
4298         ret = btrfs_unlink_subvol(trans, dir, dest->root_key.objectid,
4299                                   dentry->d_name.name, dentry->d_name.len);
4300         if (ret) {
4301                 err = ret;
4302                 btrfs_abort_transaction(trans, ret);
4303                 goto out_end_trans;
4304         }
4305
4306         btrfs_record_root_in_trans(trans, dest);
4307
4308         memset(&dest->root_item.drop_progress, 0,
4309                 sizeof(dest->root_item.drop_progress));
4310         dest->root_item.drop_level = 0;
4311         btrfs_set_root_refs(&dest->root_item, 0);
4312
4313         if (!test_and_set_bit(BTRFS_ROOT_ORPHAN_ITEM_INSERTED, &dest->state)) {
4314                 ret = btrfs_insert_orphan_item(trans,
4315                                         fs_info->tree_root,
4316                                         dest->root_key.objectid);
4317                 if (ret) {
4318                         btrfs_abort_transaction(trans, ret);
4319                         err = ret;
4320                         goto out_end_trans;
4321                 }
4322         }
4323
4324         ret = btrfs_uuid_tree_remove(trans, dest->root_item.uuid,
4325                                   BTRFS_UUID_KEY_SUBVOL,
4326                                   dest->root_key.objectid);
4327         if (ret && ret != -ENOENT) {
4328                 btrfs_abort_transaction(trans, ret);
4329                 err = ret;
4330                 goto out_end_trans;
4331         }
4332         if (!btrfs_is_empty_uuid(dest->root_item.received_uuid)) {
4333                 ret = btrfs_uuid_tree_remove(trans,
4334                                           dest->root_item.received_uuid,
4335                                           BTRFS_UUID_KEY_RECEIVED_SUBVOL,
4336                                           dest->root_key.objectid);
4337                 if (ret && ret != -ENOENT) {
4338                         btrfs_abort_transaction(trans, ret);
4339                         err = ret;
4340                         goto out_end_trans;
4341                 }
4342         }
4343
4344 out_end_trans:
4345         trans->block_rsv = NULL;
4346         trans->bytes_reserved = 0;
4347         ret = btrfs_end_transaction(trans);
4348         if (ret && !err)
4349                 err = ret;
4350         inode->i_flags |= S_DEAD;
4351 out_release:
4352         btrfs_subvolume_release_metadata(fs_info, &block_rsv);
4353 out_up_write:
4354         up_write(&fs_info->subvol_sem);
4355         if (err) {
4356                 spin_lock(&dest->root_item_lock);
4357                 root_flags = btrfs_root_flags(&dest->root_item);
4358                 btrfs_set_root_flags(&dest->root_item,
4359                                 root_flags & ~BTRFS_ROOT_SUBVOL_DEAD);
4360                 spin_unlock(&dest->root_item_lock);
4361         } else {
4362                 d_invalidate(dentry);
4363                 btrfs_prune_dentries(dest);
4364                 ASSERT(dest->send_in_progress == 0);
4365
4366                 /* the last ref */
4367                 if (dest->ino_cache_inode) {
4368                         iput(dest->ino_cache_inode);
4369                         dest->ino_cache_inode = NULL;
4370                 }
4371         }
4372
4373         return err;
4374 }
4375
4376 static int btrfs_rmdir(struct inode *dir, struct dentry *dentry)
4377 {
4378         struct inode *inode = d_inode(dentry);
4379         int err = 0;
4380         struct btrfs_root *root = BTRFS_I(dir)->root;
4381         struct btrfs_trans_handle *trans;
4382         u64 last_unlink_trans;
4383
4384         if (inode->i_size > BTRFS_EMPTY_DIR_SIZE)
4385                 return -ENOTEMPTY;
4386         if (btrfs_ino(BTRFS_I(inode)) == BTRFS_FIRST_FREE_OBJECTID)
4387                 return btrfs_delete_subvolume(dir, dentry);
4388
4389         trans = __unlink_start_trans(dir);
4390         if (IS_ERR(trans))
4391                 return PTR_ERR(trans);
4392
4393         if (unlikely(btrfs_ino(BTRFS_I(inode)) == BTRFS_EMPTY_SUBVOL_DIR_OBJECTID)) {
4394                 err = btrfs_unlink_subvol(trans, dir,
4395                                           BTRFS_I(inode)->location.objectid,
4396                                           dentry->d_name.name,
4397                                           dentry->d_name.len);
4398                 goto out;
4399         }
4400
4401         err = btrfs_orphan_add(trans, BTRFS_I(inode));
4402         if (err)
4403                 goto out;
4404
4405         last_unlink_trans = BTRFS_I(inode)->last_unlink_trans;
4406
4407         /* now the directory is empty */
4408         err = btrfs_unlink_inode(trans, root, BTRFS_I(dir),
4409                         BTRFS_I(d_inode(dentry)), dentry->d_name.name,
4410                         dentry->d_name.len);
4411         if (!err) {
4412                 btrfs_i_size_write(BTRFS_I(inode), 0);
4413                 /*
4414                  * Propagate the last_unlink_trans value of the deleted dir to
4415                  * its parent directory. This is to prevent an unrecoverable
4416                  * log tree in the case we do something like this:
4417                  * 1) create dir foo
4418                  * 2) create snapshot under dir foo
4419                  * 3) delete the snapshot
4420                  * 4) rmdir foo
4421                  * 5) mkdir foo
4422                  * 6) fsync foo or some file inside foo
4423                  */
4424                 if (last_unlink_trans >= trans->transid)
4425                         BTRFS_I(dir)->last_unlink_trans = last_unlink_trans;
4426         }
4427 out:
4428         btrfs_end_transaction(trans);
4429         btrfs_btree_balance_dirty(root->fs_info);
4430
4431         return err;
4432 }
4433
4434 static int truncate_space_check(struct btrfs_trans_handle *trans,
4435                                 struct btrfs_root *root,
4436                                 u64 bytes_deleted)
4437 {
4438         struct btrfs_fs_info *fs_info = root->fs_info;
4439         int ret;
4440
4441         /*
4442          * This is only used to apply pressure to the enospc system, we don't
4443          * intend to use this reservation at all.
4444          */
4445         bytes_deleted = btrfs_csum_bytes_to_leaves(fs_info, bytes_deleted);
4446         bytes_deleted *= fs_info->nodesize;
4447         ret = btrfs_block_rsv_add(root, &fs_info->trans_block_rsv,
4448                                   bytes_deleted, BTRFS_RESERVE_NO_FLUSH);
4449         if (!ret) {
4450                 trace_btrfs_space_reservation(fs_info, "transaction",
4451                                               trans->transid,
4452                                               bytes_deleted, 1);
4453                 trans->bytes_reserved += bytes_deleted;
4454         }
4455         return ret;
4456
4457 }
4458
4459 /*
4460  * Return this if we need to call truncate_block for the last bit of the
4461  * truncate.
4462  */
4463 #define NEED_TRUNCATE_BLOCK 1
4464
4465 /*
4466  * this can truncate away extent items, csum items and directory items.
4467  * It starts at a high offset and removes keys until it can't find
4468  * any higher than new_size
4469  *
4470  * csum items that cross the new i_size are truncated to the new size
4471  * as well.
4472  *
4473  * min_type is the minimum key type to truncate down to.  If set to 0, this
4474  * will kill all the items on this inode, including the INODE_ITEM_KEY.
4475  */
4476 int btrfs_truncate_inode_items(struct btrfs_trans_handle *trans,
4477                                struct btrfs_root *root,
4478                                struct inode *inode,
4479                                u64 new_size, u32 min_type)
4480 {
4481         struct btrfs_fs_info *fs_info = root->fs_info;
4482         struct btrfs_path *path;
4483         struct extent_buffer *leaf;
4484         struct btrfs_file_extent_item *fi;
4485         struct btrfs_key key;
4486         struct btrfs_key found_key;
4487         u64 extent_start = 0;
4488         u64 extent_num_bytes = 0;
4489         u64 extent_offset = 0;
4490         u64 item_end = 0;
4491         u64 last_size = new_size;
4492         u32 found_type = (u8)-1;
4493         int found_extent;
4494         int del_item;
4495         int pending_del_nr = 0;
4496         int pending_del_slot = 0;
4497         int extent_type = -1;
4498         int ret;
4499         u64 ino = btrfs_ino(BTRFS_I(inode));
4500         u64 bytes_deleted = 0;
4501         bool be_nice = false;
4502         bool should_throttle = false;
4503         bool should_end = false;
4504
4505         BUG_ON(new_size > 0 && min_type != BTRFS_EXTENT_DATA_KEY);
4506
4507         /*
4508          * for non-free space inodes and ref cows, we want to back off from
4509          * time to time
4510          */
4511         if (!btrfs_is_free_space_inode(BTRFS_I(inode)) &&
4512             test_bit(BTRFS_ROOT_REF_COWS, &root->state))
4513                 be_nice = true;
4514
4515         path = btrfs_alloc_path();
4516         if (!path)
4517                 return -ENOMEM;
4518         path->reada = READA_BACK;
4519
4520         /*
4521          * We want to drop from the next block forward in case this new size is
4522          * not block aligned since we will be keeping the last block of the
4523          * extent just the way it is.
4524          */
4525         if (test_bit(BTRFS_ROOT_REF_COWS, &root->state) ||
4526             root == fs_info->tree_root)
4527                 btrfs_drop_extent_cache(BTRFS_I(inode), ALIGN(new_size,
4528                                         fs_info->sectorsize),
4529                                         (u64)-1, 0);
4530
4531         /*
4532          * This function is also used to drop the items in the log tree before
4533          * we relog the inode, so if root != BTRFS_I(inode)->root, it means
4534          * it is used to drop the loged items. So we shouldn't kill the delayed
4535          * items.
4536          */
4537         if (min_type == 0 && root == BTRFS_I(inode)->root)
4538                 btrfs_kill_delayed_inode_items(BTRFS_I(inode));
4539
4540         key.objectid = ino;
4541         key.offset = (u64)-1;
4542         key.type = (u8)-1;
4543
4544 search_again:
4545         /*
4546          * with a 16K leaf size and 128MB extents, you can actually queue
4547          * up a huge file in a single leaf.  Most of the time that
4548          * bytes_deleted is > 0, it will be huge by the time we get here
4549          */
4550         if (be_nice && bytes_deleted > SZ_32M &&
4551             btrfs_should_end_transaction(trans)) {
4552                 ret = -EAGAIN;
4553                 goto out;
4554         }
4555
4556         path->leave_spinning = 1;
4557         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
4558         if (ret < 0)
4559                 goto out;
4560
4561         if (ret > 0) {
4562                 ret = 0;
4563                 /* there are no items in the tree for us to truncate, we're
4564                  * done
4565                  */
4566                 if (path->slots[0] == 0)
4567                         goto out;
4568                 path->slots[0]--;
4569         }
4570
4571         while (1) {
4572                 fi = NULL;
4573                 leaf = path->nodes[0];
4574                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
4575                 found_type = found_key.type;
4576
4577                 if (found_key.objectid != ino)
4578                         break;
4579
4580                 if (found_type < min_type)
4581                         break;
4582
4583                 item_end = found_key.offset;
4584                 if (found_type == BTRFS_EXTENT_DATA_KEY) {
4585                         fi = btrfs_item_ptr(leaf, path->slots[0],
4586                                             struct btrfs_file_extent_item);
4587                         extent_type = btrfs_file_extent_type(leaf, fi);
4588                         if (extent_type != BTRFS_FILE_EXTENT_INLINE) {
4589                                 item_end +=
4590                                     btrfs_file_extent_num_bytes(leaf, fi);
4591
4592                                 trace_btrfs_truncate_show_fi_regular(
4593                                         BTRFS_I(inode), leaf, fi,
4594                                         found_key.offset);
4595                         } else if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
4596                                 item_end += btrfs_file_extent_ram_bytes(leaf,
4597                                                                         fi);
4598
4599                                 trace_btrfs_truncate_show_fi_inline(
4600                                         BTRFS_I(inode), leaf, fi, path->slots[0],
4601                                         found_key.offset);
4602                         }
4603                         item_end--;
4604                 }
4605                 if (found_type > min_type) {
4606                         del_item = 1;
4607                 } else {
4608                         if (item_end < new_size)
4609                                 break;
4610                         if (found_key.offset >= new_size)
4611                                 del_item = 1;
4612                         else
4613                                 del_item = 0;
4614                 }
4615                 found_extent = 0;
4616                 /* FIXME, shrink the extent if the ref count is only 1 */
4617                 if (found_type != BTRFS_EXTENT_DATA_KEY)
4618                         goto delete;
4619
4620                 if (extent_type != BTRFS_FILE_EXTENT_INLINE) {
4621                         u64 num_dec;
4622                         extent_start = btrfs_file_extent_disk_bytenr(leaf, fi);
4623                         if (!del_item) {
4624                                 u64 orig_num_bytes =
4625                                         btrfs_file_extent_num_bytes(leaf, fi);
4626                                 extent_num_bytes = ALIGN(new_size -
4627                                                 found_key.offset,
4628                                                 fs_info->sectorsize);
4629                                 btrfs_set_file_extent_num_bytes(leaf, fi,
4630                                                          extent_num_bytes);
4631                                 num_dec = (orig_num_bytes -
4632                                            extent_num_bytes);
4633                                 if (test_bit(BTRFS_ROOT_REF_COWS,
4634                                              &root->state) &&
4635                                     extent_start != 0)
4636                                         inode_sub_bytes(inode, num_dec);
4637                                 btrfs_mark_buffer_dirty(leaf);
4638                         } else {
4639                                 extent_num_bytes =
4640                                         btrfs_file_extent_disk_num_bytes(leaf,
4641                                                                          fi);
4642                                 extent_offset = found_key.offset -
4643                                         btrfs_file_extent_offset(leaf, fi);
4644
4645                                 /* FIXME blocksize != 4096 */
4646                                 num_dec = btrfs_file_extent_num_bytes(leaf, fi);
4647                                 if (extent_start != 0) {
4648                                         found_extent = 1;
4649                                         if (test_bit(BTRFS_ROOT_REF_COWS,
4650                                                      &root->state))
4651                                                 inode_sub_bytes(inode, num_dec);
4652                                 }
4653                         }
4654                 } else if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
4655                         /*
4656                          * we can't truncate inline items that have had
4657                          * special encodings
4658                          */
4659                         if (!del_item &&
4660                             btrfs_file_extent_encryption(leaf, fi) == 0 &&
4661                             btrfs_file_extent_other_encoding(leaf, fi) == 0 &&
4662                             btrfs_file_extent_compression(leaf, fi) == 0) {
4663                                 u32 size = (u32)(new_size - found_key.offset);
4664
4665                                 btrfs_set_file_extent_ram_bytes(leaf, fi, size);
4666                                 size = btrfs_file_extent_calc_inline_size(size);
4667                                 btrfs_truncate_item(root->fs_info, path, size, 1);
4668                         } else if (!del_item) {
4669                                 /*
4670                                  * We have to bail so the last_size is set to
4671                                  * just before this extent.
4672                                  */
4673                                 ret = NEED_TRUNCATE_BLOCK;
4674                                 break;
4675                         }
4676
4677                         if (test_bit(BTRFS_ROOT_REF_COWS, &root->state))
4678                                 inode_sub_bytes(inode, item_end + 1 - new_size);
4679                 }
4680 delete:
4681                 if (del_item)
4682                         last_size = found_key.offset;
4683                 else
4684                         last_size = new_size;
4685                 if (del_item) {
4686                         if (!pending_del_nr) {
4687                                 /* no pending yet, add ourselves */
4688                                 pending_del_slot = path->slots[0];
4689                                 pending_del_nr = 1;
4690                         } else if (pending_del_nr &&
4691                                    path->slots[0] + 1 == pending_del_slot) {
4692                                 /* hop on the pending chunk */
4693                                 pending_del_nr++;
4694                                 pending_del_slot = path->slots[0];
4695                         } else {
4696                                 BUG();
4697                         }
4698                 } else {
4699                         break;
4700                 }
4701                 should_throttle = false;
4702
4703                 if (found_extent &&
4704                     (test_bit(BTRFS_ROOT_REF_COWS, &root->state) ||
4705                      root == fs_info->tree_root)) {
4706                         btrfs_set_path_blocking(path);
4707                         bytes_deleted += extent_num_bytes;
4708                         ret = btrfs_free_extent(trans, root, extent_start,
4709                                                 extent_num_bytes, 0,
4710                                                 btrfs_header_owner(leaf),
4711                                                 ino, extent_offset);
4712                         if (ret) {
4713                                 btrfs_abort_transaction(trans, ret);
4714                                 break;
4715                         }
4716                         if (btrfs_should_throttle_delayed_refs(trans))
4717                                 btrfs_async_run_delayed_refs(fs_info,
4718                                         trans->delayed_ref_updates * 2,
4719                                         trans->transid, 0);
4720                         if (be_nice) {
4721                                 if (truncate_space_check(trans, root,
4722                                                          extent_num_bytes)) {
4723                                         should_end = true;
4724                                 }
4725                                 if (btrfs_should_throttle_delayed_refs(trans))
4726                                         should_throttle = true;
4727                         }
4728                 }
4729
4730                 if (found_type == BTRFS_INODE_ITEM_KEY)
4731                         break;
4732
4733                 if (path->slots[0] == 0 ||
4734                     path->slots[0] != pending_del_slot ||
4735                     should_throttle || should_end) {
4736                         if (pending_del_nr) {
4737                                 ret = btrfs_del_items(trans, root, path,
4738                                                 pending_del_slot,
4739                                                 pending_del_nr);
4740                                 if (ret) {
4741                                         btrfs_abort_transaction(trans, ret);
4742                                         break;
4743                                 }
4744                                 pending_del_nr = 0;
4745                         }
4746                         btrfs_release_path(path);
4747                         if (should_throttle) {
4748                                 unsigned long updates = trans->delayed_ref_updates;
4749                                 if (updates) {
4750                                         trans->delayed_ref_updates = 0;
4751                                         ret = btrfs_run_delayed_refs(trans,
4752                                                                    updates * 2);
4753                                         if (ret)
4754                                                 break;
4755                                 }
4756                         }
4757                         /*
4758                          * if we failed to refill our space rsv, bail out
4759                          * and let the transaction restart
4760                          */
4761                         if (should_end) {
4762                                 ret = -EAGAIN;
4763                                 break;
4764                         }
4765                         goto search_again;
4766                 } else {
4767                         path->slots[0]--;
4768                 }
4769         }
4770 out:
4771         if (ret >= 0 && pending_del_nr) {
4772                 int err;
4773
4774                 err = btrfs_del_items(trans, root, path, pending_del_slot,
4775                                       pending_del_nr);
4776                 if (err) {
4777                         btrfs_abort_transaction(trans, err);
4778                         ret = err;
4779                 }
4780         }
4781         if (root->root_key.objectid != BTRFS_TREE_LOG_OBJECTID) {
4782                 ASSERT(last_size >= new_size);
4783                 if (!ret && last_size > new_size)
4784                         last_size = new_size;
4785                 btrfs_ordered_update_i_size(inode, last_size, NULL);
4786         }
4787
4788         btrfs_free_path(path);
4789
4790         if (be_nice && bytes_deleted > SZ_32M && (ret >= 0 || ret == -EAGAIN)) {
4791                 unsigned long updates = trans->delayed_ref_updates;
4792                 int err;
4793
4794                 if (updates) {
4795                         trans->delayed_ref_updates = 0;
4796                         err = btrfs_run_delayed_refs(trans, updates * 2);
4797                         if (err)
4798                                 ret = err;
4799                 }
4800         }
4801         return ret;
4802 }
4803
4804 /*
4805  * btrfs_truncate_block - read, zero a chunk and write a block
4806  * @inode - inode that we're zeroing
4807  * @from - the offset to start zeroing
4808  * @len - the length to zero, 0 to zero the entire range respective to the
4809  *      offset
4810  * @front - zero up to the offset instead of from the offset on
4811  *
4812  * This will find the block for the "from" offset and cow the block and zero the
4813  * part we want to zero.  This is used with truncate and hole punching.
4814  */
4815 int btrfs_truncate_block(struct inode *inode, loff_t from, loff_t len,
4816                         int front)
4817 {
4818         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
4819         struct address_space *mapping = inode->i_mapping;
4820         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
4821         struct btrfs_ordered_extent *ordered;
4822         struct extent_state *cached_state = NULL;
4823         struct extent_changeset *data_reserved = NULL;
4824         char *kaddr;
4825         u32 blocksize = fs_info->sectorsize;
4826         pgoff_t index = from >> PAGE_SHIFT;
4827         unsigned offset = from & (blocksize - 1);
4828         struct page *page;
4829         gfp_t mask = btrfs_alloc_write_mask(mapping);
4830         int ret = 0;
4831         u64 block_start;
4832         u64 block_end;
4833
4834         if (IS_ALIGNED(offset, blocksize) &&
4835             (!len || IS_ALIGNED(len, blocksize)))
4836                 goto out;
4837
4838         block_start = round_down(from, blocksize);
4839         block_end = block_start + blocksize - 1;
4840
4841         ret = btrfs_delalloc_reserve_space(inode, &data_reserved,
4842                                            block_start, blocksize);
4843         if (ret)
4844                 goto out;
4845
4846 again:
4847         page = find_or_create_page(mapping, index, mask);
4848         if (!page) {
4849                 btrfs_delalloc_release_space(inode, data_reserved,
4850                                              block_start, blocksize, true);
4851                 btrfs_delalloc_release_extents(BTRFS_I(inode), blocksize, true);
4852                 ret = -ENOMEM;
4853                 goto out;
4854         }
4855
4856         if (!PageUptodate(page)) {
4857                 ret = btrfs_readpage(NULL, page);
4858                 lock_page(page);
4859                 if (page->mapping != mapping) {
4860                         unlock_page(page);
4861                         put_page(page);
4862                         goto again;
4863                 }
4864                 if (!PageUptodate(page)) {
4865                         ret = -EIO;
4866                         goto out_unlock;
4867                 }
4868         }
4869         wait_on_page_writeback(page);
4870
4871         lock_extent_bits(io_tree, block_start, block_end, &cached_state);
4872         set_page_extent_mapped(page);
4873
4874         ordered = btrfs_lookup_ordered_extent(inode, block_start);
4875         if (ordered) {
4876                 unlock_extent_cached(io_tree, block_start, block_end,
4877                                      &cached_state);
4878                 unlock_page(page);
4879                 put_page(page);
4880                 btrfs_start_ordered_extent(inode, ordered, 1);
4881                 btrfs_put_ordered_extent(ordered);
4882                 goto again;
4883         }
4884
4885         clear_extent_bit(&BTRFS_I(inode)->io_tree, block_start, block_end,
4886                           EXTENT_DIRTY | EXTENT_DELALLOC |
4887                           EXTENT_DO_ACCOUNTING | EXTENT_DEFRAG,
4888                           0, 0, &cached_state);
4889
4890         ret = btrfs_set_extent_delalloc(inode, block_start, block_end, 0,
4891                                         &cached_state, 0);
4892         if (ret) {
4893                 unlock_extent_cached(io_tree, block_start, block_end,
4894                                      &cached_state);
4895                 goto out_unlock;
4896         }
4897
4898         if (offset != blocksize) {
4899                 if (!len)
4900                         len = blocksize - offset;
4901                 kaddr = kmap(page);
4902                 if (front)
4903                         memset(kaddr + (block_start - page_offset(page)),
4904                                 0, offset);
4905                 else
4906                         memset(kaddr + (block_start - page_offset(page)) +  offset,
4907                                 0, len);
4908                 flush_dcache_page(page);
4909                 kunmap(page);
4910         }
4911         ClearPageChecked(page);
4912         set_page_dirty(page);
4913         unlock_extent_cached(io_tree, block_start, block_end, &cached_state);
4914
4915 out_unlock:
4916         if (ret)
4917                 btrfs_delalloc_release_space(inode, data_reserved, block_start,
4918                                              blocksize, true);
4919         btrfs_delalloc_release_extents(BTRFS_I(inode), blocksize, (ret != 0));
4920         unlock_page(page);
4921         put_page(page);
4922 out:
4923         extent_changeset_free(data_reserved);
4924         return ret;
4925 }
4926
4927 static int maybe_insert_hole(struct btrfs_root *root, struct inode *inode,
4928                              u64 offset, u64 len)
4929 {
4930         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
4931         struct btrfs_trans_handle *trans;
4932         int ret;
4933
4934         /*
4935          * Still need to make sure the inode looks like it's been updated so
4936          * that any holes get logged if we fsync.
4937          */
4938         if (btrfs_fs_incompat(fs_info, NO_HOLES)) {
4939                 BTRFS_I(inode)->last_trans = fs_info->generation;
4940                 BTRFS_I(inode)->last_sub_trans = root->log_transid;
4941                 BTRFS_I(inode)->last_log_commit = root->last_log_commit;
4942                 return 0;
4943         }
4944
4945         /*
4946          * 1 - for the one we're dropping
4947          * 1 - for the one we're adding
4948          * 1 - for updating the inode.
4949          */
4950         trans = btrfs_start_transaction(root, 3);
4951         if (IS_ERR(trans))
4952                 return PTR_ERR(trans);
4953
4954         ret = btrfs_drop_extents(trans, root, inode, offset, offset + len, 1);
4955         if (ret) {
4956                 btrfs_abort_transaction(trans, ret);
4957                 btrfs_end_transaction(trans);
4958                 return ret;
4959         }
4960
4961         ret = btrfs_insert_file_extent(trans, root, btrfs_ino(BTRFS_I(inode)),
4962                         offset, 0, 0, len, 0, len, 0, 0, 0);
4963         if (ret)
4964                 btrfs_abort_transaction(trans, ret);
4965         else
4966                 btrfs_update_inode(trans, root, inode);
4967         btrfs_end_transaction(trans);
4968         return ret;
4969 }
4970
4971 /*
4972  * This function puts in dummy file extents for the area we're creating a hole
4973  * for.  So if we are truncating this file to a larger size we need to insert
4974  * these file extents so that btrfs_get_extent will return a EXTENT_MAP_HOLE for
4975  * the range between oldsize and size
4976  */
4977 int btrfs_cont_expand(struct inode *inode, loff_t oldsize, loff_t size)
4978 {
4979         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
4980         struct btrfs_root *root = BTRFS_I(inode)->root;
4981         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
4982         struct extent_map *em = NULL;
4983         struct extent_state *cached_state = NULL;
4984         struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
4985         u64 hole_start = ALIGN(oldsize, fs_info->sectorsize);
4986         u64 block_end = ALIGN(size, fs_info->sectorsize);
4987         u64 last_byte;
4988         u64 cur_offset;
4989         u64 hole_size;
4990         int err = 0;
4991
4992         /*
4993          * If our size started in the middle of a block we need to zero out the
4994          * rest of the block before we expand the i_size, otherwise we could
4995          * expose stale data.
4996          */
4997         err = btrfs_truncate_block(inode, oldsize, 0, 0);
4998         if (err)
4999                 return err;
5000
5001         if (size <= hole_start)
5002                 return 0;
5003
5004         while (1) {
5005                 struct btrfs_ordered_extent *ordered;
5006
5007                 lock_extent_bits(io_tree, hole_start, block_end - 1,
5008                                  &cached_state);
5009                 ordered = btrfs_lookup_ordered_range(BTRFS_I(inode), hole_start,
5010                                                      block_end - hole_start);
5011                 if (!ordered)
5012                         break;
5013                 unlock_extent_cached(io_tree, hole_start, block_end - 1,
5014                                      &cached_state);
5015                 btrfs_start_ordered_extent(inode, ordered, 1);
5016                 btrfs_put_ordered_extent(ordered);
5017         }
5018
5019         cur_offset = hole_start;
5020         while (1) {
5021                 em = btrfs_get_extent(BTRFS_I(inode), NULL, 0, cur_offset,
5022                                 block_end - cur_offset, 0);
5023                 if (IS_ERR(em)) {
5024                         err = PTR_ERR(em);
5025                         em = NULL;
5026                         break;
5027                 }
5028                 last_byte = min(extent_map_end(em), block_end);
5029                 last_byte = ALIGN(last_byte, fs_info->sectorsize);
5030                 if (!test_bit(EXTENT_FLAG_PREALLOC, &em->flags)) {
5031                         struct extent_map *hole_em;
5032                         hole_size = last_byte - cur_offset;
5033
5034                         err = maybe_insert_hole(root, inode, cur_offset,
5035                                                 hole_size);
5036                         if (err)
5037                                 break;
5038                         btrfs_drop_extent_cache(BTRFS_I(inode), cur_offset,
5039                                                 cur_offset + hole_size - 1, 0);
5040                         hole_em = alloc_extent_map();
5041                         if (!hole_em) {
5042                                 set_bit(BTRFS_INODE_NEEDS_FULL_SYNC,
5043                                         &BTRFS_I(inode)->runtime_flags);
5044                                 goto next;
5045                         }
5046                         hole_em->start = cur_offset;
5047                         hole_em->len = hole_size;
5048                         hole_em->orig_start = cur_offset;
5049
5050                         hole_em->block_start = EXTENT_MAP_HOLE;
5051                         hole_em->block_len = 0;
5052                         hole_em->orig_block_len = 0;
5053                         hole_em->ram_bytes = hole_size;
5054                         hole_em->bdev = fs_info->fs_devices->latest_bdev;
5055                         hole_em->compress_type = BTRFS_COMPRESS_NONE;
5056                         hole_em->generation = fs_info->generation;
5057
5058                         while (1) {
5059                                 write_lock(&em_tree->lock);
5060                                 err = add_extent_mapping(em_tree, hole_em, 1);
5061                                 write_unlock(&em_tree->lock);
5062                                 if (err != -EEXIST)
5063                                         break;
5064                                 btrfs_drop_extent_cache(BTRFS_I(inode),
5065                                                         cur_offset,
5066                                                         cur_offset +
5067                                                         hole_size - 1, 0);
5068                         }
5069                         free_extent_map(hole_em);
5070                 }
5071 next:
5072                 free_extent_map(em);
5073                 em = NULL;
5074                 cur_offset = last_byte;
5075                 if (cur_offset >= block_end)
5076                         break;
5077         }
5078         free_extent_map(em);
5079         unlock_extent_cached(io_tree, hole_start, block_end - 1, &cached_state);
5080         return err;
5081 }
5082
5083 static int btrfs_setsize(struct inode *inode, struct iattr *attr)
5084 {
5085         struct btrfs_root *root = BTRFS_I(inode)->root;
5086         struct btrfs_trans_handle *trans;
5087         loff_t oldsize = i_size_read(inode);
5088         loff_t newsize = attr->ia_size;
5089         int mask = attr->ia_valid;
5090         int ret;
5091
5092         /*
5093          * The regular truncate() case without ATTR_CTIME and ATTR_MTIME is a
5094          * special case where we need to update the times despite not having
5095          * these flags set.  For all other operations the VFS set these flags
5096          * explicitly if it wants a timestamp update.
5097          */
5098         if (newsize != oldsize) {
5099                 inode_inc_iversion(inode);
5100                 if (!(mask & (ATTR_CTIME | ATTR_MTIME)))
5101                         inode->i_ctime = inode->i_mtime =
5102                                 current_time(inode);
5103         }
5104
5105         if (newsize > oldsize) {
5106                 /*
5107                  * Don't do an expanding truncate while snapshotting is ongoing.
5108                  * This is to ensure the snapshot captures a fully consistent
5109                  * state of this file - if the snapshot captures this expanding
5110                  * truncation, it must capture all writes that happened before
5111                  * this truncation.
5112                  */
5113                 btrfs_wait_for_snapshot_creation(root);
5114                 ret = btrfs_cont_expand(inode, oldsize, newsize);
5115                 if (ret) {
5116                         btrfs_end_write_no_snapshotting(root);
5117                         return ret;
5118                 }
5119
5120                 trans = btrfs_start_transaction(root, 1);
5121                 if (IS_ERR(trans)) {
5122                         btrfs_end_write_no_snapshotting(root);
5123                         return PTR_ERR(trans);
5124                 }
5125
5126                 i_size_write(inode, newsize);
5127                 btrfs_ordered_update_i_size(inode, i_size_read(inode), NULL);
5128                 pagecache_isize_extended(inode, oldsize, newsize);
5129                 ret = btrfs_update_inode(trans, root, inode);
5130                 btrfs_end_write_no_snapshotting(root);
5131                 btrfs_end_transaction(trans);
5132         } else {
5133
5134                 /*
5135                  * We're truncating a file that used to have good data down to
5136                  * zero. Make sure it gets into the ordered flush list so that
5137                  * any new writes get down to disk quickly.
5138                  */
5139                 if (newsize == 0)
5140                         set_bit(BTRFS_INODE_ORDERED_DATA_CLOSE,
5141                                 &BTRFS_I(inode)->runtime_flags);
5142
5143                 truncate_setsize(inode, newsize);
5144
5145                 /* Disable nonlocked read DIO to avoid the end less truncate */
5146                 btrfs_inode_block_unlocked_dio(BTRFS_I(inode));
5147                 inode_dio_wait(inode);
5148                 btrfs_inode_resume_unlocked_dio(BTRFS_I(inode));
5149
5150                 ret = btrfs_truncate(inode, newsize == oldsize);
5151                 if (ret && inode->i_nlink) {
5152                         int err;
5153
5154                         /*
5155                          * Truncate failed, so fix up the in-memory size. We
5156                          * adjusted disk_i_size down as we removed extents, so
5157                          * wait for disk_i_size to be stable and then update the
5158                          * in-memory size to match.
5159                          */
5160                         err = btrfs_wait_ordered_range(inode, 0, (u64)-1);
5161                         if (err)
5162                                 return err;
5163                         i_size_write(inode, BTRFS_I(inode)->disk_i_size);
5164                 }
5165         }
5166
5167         return ret;
5168 }
5169
5170 static int btrfs_setattr(struct dentry *dentry, struct iattr *attr)
5171 {
5172         struct inode *inode = d_inode(dentry);
5173         struct btrfs_root *root = BTRFS_I(inode)->root;
5174         int err;
5175
5176         if (btrfs_root_readonly(root))
5177                 return -EROFS;
5178
5179         err = setattr_prepare(dentry, attr);
5180         if (err)
5181                 return err;
5182
5183         if (S_ISREG(inode->i_mode) && (attr->ia_valid & ATTR_SIZE)) {
5184                 err = btrfs_setsize(inode, attr);
5185                 if (err)
5186                         return err;
5187         }
5188
5189         if (attr->ia_valid) {
5190                 setattr_copy(inode, attr);
5191                 inode_inc_iversion(inode);
5192                 err = btrfs_dirty_inode(inode);
5193
5194                 if (!err && attr->ia_valid & ATTR_MODE)
5195                         err = posix_acl_chmod(inode, inode->i_mode);
5196         }
5197
5198         return err;
5199 }
5200
5201 /*
5202  * While truncating the inode pages during eviction, we get the VFS calling
5203  * btrfs_invalidatepage() against each page of the inode. This is slow because
5204  * the calls to btrfs_invalidatepage() result in a huge amount of calls to
5205  * lock_extent_bits() and clear_extent_bit(), which keep merging and splitting
5206  * extent_state structures over and over, wasting lots of time.
5207  *
5208  * Therefore if the inode is being evicted, let btrfs_invalidatepage() skip all
5209  * those expensive operations on a per page basis and do only the ordered io
5210  * finishing, while we release here the extent_map and extent_state structures,
5211  * without the excessive merging and splitting.
5212  */
5213 static void evict_inode_truncate_pages(struct inode *inode)
5214 {
5215         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
5216         struct extent_map_tree *map_tree = &BTRFS_I(inode)->extent_tree;
5217         struct rb_node *node;
5218
5219         ASSERT(inode->i_state & I_FREEING);
5220         truncate_inode_pages_final(&inode->i_data);
5221
5222         write_lock(&map_tree->lock);
5223         while (!RB_EMPTY_ROOT(&map_tree->map.rb_root)) {
5224                 struct extent_map *em;
5225
5226                 node = rb_first_cached(&map_tree->map);
5227                 em = rb_entry(node, struct extent_map, rb_node);
5228                 clear_bit(EXTENT_FLAG_PINNED, &em->flags);
5229                 clear_bit(EXTENT_FLAG_LOGGING, &em->flags);
5230                 remove_extent_mapping(map_tree, em);
5231                 free_extent_map(em);
5232                 if (need_resched()) {
5233                         write_unlock(&map_tree->lock);
5234                         cond_resched();
5235                         write_lock(&map_tree->lock);
5236                 }
5237         }
5238         write_unlock(&map_tree->lock);
5239
5240         /*
5241          * Keep looping until we have no more ranges in the io tree.
5242          * We can have ongoing bios started by readpages (called from readahead)
5243          * that have their endio callback (extent_io.c:end_bio_extent_readpage)
5244          * still in progress (unlocked the pages in the bio but did not yet
5245          * unlocked the ranges in the io tree). Therefore this means some
5246          * ranges can still be locked and eviction started because before
5247          * submitting those bios, which are executed by a separate task (work
5248          * queue kthread), inode references (inode->i_count) were not taken
5249          * (which would be dropped in the end io callback of each bio).
5250          * Therefore here we effectively end up waiting for those bios and
5251          * anyone else holding locked ranges without having bumped the inode's
5252          * reference count - if we don't do it, when they access the inode's
5253          * io_tree to unlock a range it may be too late, leading to an
5254          * use-after-free issue.
5255          */
5256         spin_lock(&io_tree->lock);
5257         while (!RB_EMPTY_ROOT(&io_tree->state)) {
5258                 struct extent_state *state;
5259                 struct extent_state *cached_state = NULL;
5260                 u64 start;
5261                 u64 end;
5262
5263                 node = rb_first(&io_tree->state);
5264                 state = rb_entry(node, struct extent_state, rb_node);
5265                 start = state->start;
5266                 end = state->end;
5267                 spin_unlock(&io_tree->lock);
5268
5269                 lock_extent_bits(io_tree, start, end, &cached_state);
5270
5271                 /*
5272                  * If still has DELALLOC flag, the extent didn't reach disk,
5273                  * and its reserved space won't be freed by delayed_ref.
5274                  * So we need to free its reserved space here.
5275                  * (Refer to comment in btrfs_invalidatepage, case 2)
5276                  *
5277                  * Note, end is the bytenr of last byte, so we need + 1 here.
5278                  */
5279                 if (state->state & EXTENT_DELALLOC)
5280                         btrfs_qgroup_free_data(inode, NULL, start, end - start + 1);
5281
5282                 clear_extent_bit(io_tree, start, end,
5283                                  EXTENT_LOCKED | EXTENT_DIRTY |
5284                                  EXTENT_DELALLOC | EXTENT_DO_ACCOUNTING |
5285                                  EXTENT_DEFRAG, 1, 1, &cached_state);
5286
5287                 cond_resched();
5288                 spin_lock(&io_tree->lock);
5289         }
5290         spin_unlock(&io_tree->lock);
5291 }
5292
5293 static struct btrfs_trans_handle *evict_refill_and_join(struct btrfs_root *root,
5294                                                         struct btrfs_block_rsv *rsv)
5295 {
5296         struct btrfs_fs_info *fs_info = root->fs_info;
5297         struct btrfs_block_rsv *global_rsv = &fs_info->global_block_rsv;
5298         int failures = 0;
5299
5300         for (;;) {
5301                 struct btrfs_trans_handle *trans;
5302                 int ret;
5303
5304                 ret = btrfs_block_rsv_refill(root, rsv, rsv->size,
5305                                              BTRFS_RESERVE_FLUSH_LIMIT);
5306
5307                 if (ret && ++failures > 2) {
5308                         btrfs_warn(fs_info,
5309                                    "could not allocate space for a delete; will truncate on mount");
5310                         return ERR_PTR(-ENOSPC);
5311                 }
5312
5313                 trans = btrfs_join_transaction(root);
5314                 if (IS_ERR(trans) || !ret)
5315                         return trans;
5316
5317                 /*
5318                  * Try to steal from the global reserve if there is space for
5319                  * it.
5320                  */
5321                 if (!btrfs_check_space_for_delayed_refs(trans) &&
5322                     !btrfs_block_rsv_migrate(global_rsv, rsv, rsv->size, false))
5323                         return trans;
5324
5325                 /* If not, commit and try again. */
5326                 ret = btrfs_commit_transaction(trans);
5327                 if (ret)
5328                         return ERR_PTR(ret);
5329         }
5330 }
5331
5332 void btrfs_evict_inode(struct inode *inode)
5333 {
5334         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
5335         struct btrfs_trans_handle *trans;
5336         struct btrfs_root *root = BTRFS_I(inode)->root;
5337         struct btrfs_block_rsv *rsv;
5338         int ret;
5339
5340         trace_btrfs_inode_evict(inode);
5341
5342         if (!root) {
5343                 clear_inode(inode);
5344                 return;
5345         }
5346
5347         evict_inode_truncate_pages(inode);
5348
5349         if (inode->i_nlink &&
5350             ((btrfs_root_refs(&root->root_item) != 0 &&
5351               root->root_key.objectid != BTRFS_ROOT_TREE_OBJECTID) ||
5352              btrfs_is_free_space_inode(BTRFS_I(inode))))
5353                 goto no_delete;
5354
5355         if (is_bad_inode(inode))
5356                 goto no_delete;
5357
5358         btrfs_free_io_failure_record(BTRFS_I(inode), 0, (u64)-1);
5359
5360         if (test_bit(BTRFS_FS_LOG_RECOVERING, &fs_info->flags))
5361                 goto no_delete;
5362
5363         if (inode->i_nlink > 0) {
5364                 BUG_ON(btrfs_root_refs(&root->root_item) != 0 &&
5365                        root->root_key.objectid != BTRFS_ROOT_TREE_OBJECTID);
5366                 goto no_delete;
5367         }
5368
5369         ret = btrfs_commit_inode_delayed_inode(BTRFS_I(inode));
5370         if (ret)
5371                 goto no_delete;
5372
5373         rsv = btrfs_alloc_block_rsv(fs_info, BTRFS_BLOCK_RSV_TEMP);
5374         if (!rsv)
5375                 goto no_delete;
5376         rsv->size = btrfs_calc_trunc_metadata_size(fs_info, 1);
5377         rsv->failfast = 1;
5378
5379         btrfs_i_size_write(BTRFS_I(inode), 0);
5380
5381         while (1) {
5382                 trans = evict_refill_and_join(root, rsv);
5383                 if (IS_ERR(trans))
5384                         goto free_rsv;
5385
5386                 trans->block_rsv = rsv;
5387
5388                 ret = btrfs_truncate_inode_items(trans, root, inode, 0, 0);
5389                 trans->block_rsv = &fs_info->trans_block_rsv;
5390                 btrfs_end_transaction(trans);
5391                 btrfs_btree_balance_dirty(fs_info);
5392                 if (ret && ret != -ENOSPC && ret != -EAGAIN)
5393                         goto free_rsv;
5394                 else if (!ret)
5395                         break;
5396         }
5397
5398         /*
5399          * Errors here aren't a big deal, it just means we leave orphan items in
5400          * the tree. They will be cleaned up on the next mount. If the inode
5401          * number gets reused, cleanup deletes the orphan item without doing
5402          * anything, and unlink reuses the existing orphan item.
5403          *
5404          * If it turns out that we are dropping too many of these, we might want
5405          * to add a mechanism for retrying these after a commit.
5406          */
5407         trans = evict_refill_and_join(root, rsv);
5408         if (!IS_ERR(trans)) {
5409                 trans->block_rsv = rsv;
5410                 btrfs_orphan_del(trans, BTRFS_I(inode));
5411                 trans->block_rsv = &fs_info->trans_block_rsv;
5412                 btrfs_end_transaction(trans);
5413         }
5414
5415         if (!(root == fs_info->tree_root ||
5416               root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID))
5417                 btrfs_return_ino(root, btrfs_ino(BTRFS_I(inode)));
5418
5419 free_rsv:
5420         btrfs_free_block_rsv(fs_info, rsv);
5421 no_delete:
5422         /*
5423          * If we didn't successfully delete, the orphan item will still be in
5424          * the tree and we'll retry on the next mount. Again, we might also want
5425          * to retry these periodically in the future.
5426          */
5427         btrfs_remove_delayed_node(BTRFS_I(inode));
5428         clear_inode(inode);
5429 }
5430
5431 /*
5432  * this returns the key found in the dir entry in the location pointer.
5433  * If no dir entries were found, returns -ENOENT.
5434  * If found a corrupted location in dir entry, returns -EUCLEAN.
5435  */
5436 static int btrfs_inode_by_name(struct inode *dir, struct dentry *dentry,
5437                                struct btrfs_key *location)
5438 {
5439         const char *name = dentry->d_name.name;
5440         int namelen = dentry->d_name.len;
5441         struct btrfs_dir_item *di;
5442         struct btrfs_path *path;
5443         struct btrfs_root *root = BTRFS_I(dir)->root;
5444         int ret = 0;
5445
5446         path = btrfs_alloc_path();
5447         if (!path)
5448                 return -ENOMEM;
5449
5450         di = btrfs_lookup_dir_item(NULL, root, path, btrfs_ino(BTRFS_I(dir)),
5451                         name, namelen, 0);
5452         if (IS_ERR_OR_NULL(di)) {
5453                 ret = di ? PTR_ERR(di) : -ENOENT;
5454                 goto out;
5455         }
5456
5457         btrfs_dir_item_key_to_cpu(path->nodes[0], di, location);
5458         if (location->type != BTRFS_INODE_ITEM_KEY &&
5459             location->type != BTRFS_ROOT_ITEM_KEY) {
5460                 ret = -EUCLEAN;
5461                 btrfs_warn(root->fs_info,
5462 "%s gets something invalid in DIR_ITEM (name %s, directory ino %llu, location(%llu %u %llu))",
5463                            __func__, name, btrfs_ino(BTRFS_I(dir)),
5464                            location->objectid, location->type, location->offset);
5465         }
5466 out:
5467         btrfs_free_path(path);
5468         return ret;
5469 }
5470
5471 /*
5472  * when we hit a tree root in a directory, the btrfs part of the inode
5473  * needs to be changed to reflect the root directory of the tree root.  This
5474  * is kind of like crossing a mount point.
5475  */
5476 static int fixup_tree_root_location(struct btrfs_fs_info *fs_info,
5477                                     struct inode *dir,
5478                                     struct dentry *dentry,
5479                                     struct btrfs_key *location,
5480                                     struct btrfs_root **sub_root)
5481 {
5482         struct btrfs_path *path;
5483         struct btrfs_root *new_root;
5484         struct btrfs_root_ref *ref;
5485         struct extent_buffer *leaf;
5486         struct btrfs_key key;
5487         int ret;
5488         int err = 0;
5489
5490         path = btrfs_alloc_path();
5491         if (!path) {
5492                 err = -ENOMEM;
5493                 goto out;
5494         }
5495
5496         err = -ENOENT;
5497         key.objectid = BTRFS_I(dir)->root->root_key.objectid;
5498         key.type = BTRFS_ROOT_REF_KEY;
5499         key.offset = location->objectid;
5500
5501         ret = btrfs_search_slot(NULL, fs_info->tree_root, &key, path, 0, 0);
5502         if (ret) {
5503                 if (ret < 0)
5504                         err = ret;
5505                 goto out;
5506         }
5507
5508         leaf = path->nodes[0];
5509         ref = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_root_ref);
5510         if (btrfs_root_ref_dirid(leaf, ref) != btrfs_ino(BTRFS_I(dir)) ||
5511             btrfs_root_ref_name_len(leaf, ref) != dentry->d_name.len)
5512                 goto out;
5513
5514         ret = memcmp_extent_buffer(leaf, dentry->d_name.name,
5515                                    (unsigned long)(ref + 1),
5516                                    dentry->d_name.len);
5517         if (ret)
5518                 goto out;
5519
5520         btrfs_release_path(path);
5521
5522         new_root = btrfs_read_fs_root_no_name(fs_info, location);
5523         if (IS_ERR(new_root)) {
5524                 err = PTR_ERR(new_root);
5525                 goto out;
5526         }
5527
5528         *sub_root = new_root;
5529         location->objectid = btrfs_root_dirid(&new_root->root_item);
5530         location->type = BTRFS_INODE_ITEM_KEY;
5531         location->offset = 0;
5532         err = 0;
5533 out:
5534         btrfs_free_path(path);
5535         return err;
5536 }
5537
5538 static void inode_tree_add(struct inode *inode)
5539 {
5540         struct btrfs_root *root = BTRFS_I(inode)->root;
5541         struct btrfs_inode *entry;
5542         struct rb_node **p;
5543         struct rb_node *parent;
5544         struct rb_node *new = &BTRFS_I(inode)->rb_node;
5545         u64 ino = btrfs_ino(BTRFS_I(inode));
5546
5547         if (inode_unhashed(inode))
5548                 return;
5549         parent = NULL;
5550         spin_lock(&root->inode_lock);
5551         p = &root->inode_tree.rb_node;
5552         while (*p) {
5553                 parent = *p;
5554                 entry = rb_entry(parent, struct btrfs_inode, rb_node);
5555
5556                 if (ino < btrfs_ino(entry))
5557                         p = &parent->rb_left;
5558                 else if (ino > btrfs_ino(entry))
5559                         p = &parent->rb_right;
5560                 else {
5561                         WARN_ON(!(entry->vfs_inode.i_state &
5562                                   (I_WILL_FREE | I_FREEING)));
5563                         rb_replace_node(parent, new, &root->inode_tree);
5564                         RB_CLEAR_NODE(parent);
5565                         spin_unlock(&root->inode_lock);
5566                         return;
5567                 }
5568         }
5569         rb_link_node(new, parent, p);
5570         rb_insert_color(new, &root->inode_tree);
5571         spin_unlock(&root->inode_lock);
5572 }
5573
5574 static void inode_tree_del(struct inode *inode)
5575 {
5576         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
5577         struct btrfs_root *root = BTRFS_I(inode)->root;
5578         int empty = 0;
5579
5580         spin_lock(&root->inode_lock);
5581         if (!RB_EMPTY_NODE(&BTRFS_I(inode)->rb_node)) {
5582                 rb_erase(&BTRFS_I(inode)->rb_node, &root->inode_tree);
5583                 RB_CLEAR_NODE(&BTRFS_I(inode)->rb_node);
5584                 empty = RB_EMPTY_ROOT(&root->inode_tree);
5585         }
5586         spin_unlock(&root->inode_lock);
5587
5588         if (empty && btrfs_root_refs(&root->root_item) == 0) {
5589                 synchronize_srcu(&fs_info->subvol_srcu);
5590                 spin_lock(&root->inode_lock);
5591                 empty = RB_EMPTY_ROOT(&root->inode_tree);
5592                 spin_unlock(&root->inode_lock);
5593                 if (empty)
5594                         btrfs_add_dead_root(root);
5595         }
5596 }
5597
5598
5599 static int btrfs_init_locked_inode(struct inode *inode, void *p)
5600 {
5601         struct btrfs_iget_args *args = p;
5602         inode->i_ino = args->location->objectid;
5603         memcpy(&BTRFS_I(inode)->location, args->location,
5604                sizeof(*args->location));
5605         BTRFS_I(inode)->root = args->root;
5606         return 0;
5607 }
5608
5609 static int btrfs_find_actor(struct inode *inode, void *opaque)
5610 {
5611         struct btrfs_iget_args *args = opaque;
5612         return args->location->objectid == BTRFS_I(inode)->location.objectid &&
5613                 args->root == BTRFS_I(inode)->root;
5614 }
5615
5616 static struct inode *btrfs_iget_locked(struct super_block *s,
5617                                        struct btrfs_key *location,
5618                                        struct btrfs_root *root)
5619 {
5620         struct inode *inode;
5621         struct btrfs_iget_args args;
5622         unsigned long hashval = btrfs_inode_hash(location->objectid, root);
5623
5624         args.location = location;
5625         args.root = root;
5626
5627         inode = iget5_locked(s, hashval, btrfs_find_actor,
5628                              btrfs_init_locked_inode,
5629                              (void *)&args);
5630         return inode;
5631 }
5632
5633 /* Get an inode object given its location and corresponding root.
5634  * Returns in *is_new if the inode was read from disk
5635  */
5636 struct inode *btrfs_iget(struct super_block *s, struct btrfs_key *location,
5637                          struct btrfs_root *root, int *new)
5638 {
5639         struct inode *inode;
5640
5641         inode = btrfs_iget_locked(s, location, root);
5642         if (!inode)
5643                 return ERR_PTR(-ENOMEM);
5644
5645         if (inode->i_state & I_NEW) {
5646                 int ret;
5647
5648                 ret = btrfs_read_locked_inode(inode);
5649                 if (!ret) {
5650                         inode_tree_add(inode);
5651                         unlock_new_inode(inode);
5652                         if (new)
5653                                 *new = 1;
5654                 } else {
5655                         iget_failed(inode);
5656                         /*
5657                          * ret > 0 can come from btrfs_search_slot called by
5658                          * btrfs_read_locked_inode, this means the inode item
5659                          * was not found.
5660                          */
5661                         if (ret > 0)
5662                                 ret = -ENOENT;
5663                         inode = ERR_PTR(ret);
5664                 }
5665         }
5666
5667         return inode;
5668 }
5669
5670 static struct inode *new_simple_dir(struct super_block *s,
5671                                     struct btrfs_key *key,
5672                                     struct btrfs_root *root)
5673 {
5674         struct inode *inode = new_inode(s);
5675
5676         if (!inode)
5677                 return ERR_PTR(-ENOMEM);
5678
5679         BTRFS_I(inode)->root = root;
5680         memcpy(&BTRFS_I(inode)->location, key, sizeof(*key));
5681         set_bit(BTRFS_INODE_DUMMY, &BTRFS_I(inode)->runtime_flags);
5682
5683         inode->i_ino = BTRFS_EMPTY_SUBVOL_DIR_OBJECTID;
5684         inode->i_op = &btrfs_dir_ro_inode_operations;
5685         inode->i_opflags &= ~IOP_XATTR;
5686         inode->i_fop = &simple_dir_operations;
5687         inode->i_mode = S_IFDIR | S_IRUGO | S_IWUSR | S_IXUGO;
5688         inode->i_mtime = current_time(inode);
5689         inode->i_atime = inode->i_mtime;
5690         inode->i_ctime = inode->i_mtime;
5691         BTRFS_I(inode)->i_otime = inode->i_mtime;
5692
5693         return inode;
5694 }
5695
5696 struct inode *btrfs_lookup_dentry(struct inode *dir, struct dentry *dentry)
5697 {
5698         struct btrfs_fs_info *fs_info = btrfs_sb(dir->i_sb);
5699         struct inode *inode;
5700         struct btrfs_root *root = BTRFS_I(dir)->root;
5701         struct btrfs_root *sub_root = root;
5702         struct btrfs_key location;
5703         int index;
5704         int ret = 0;
5705
5706         if (dentry->d_name.len > BTRFS_NAME_LEN)
5707                 return ERR_PTR(-ENAMETOOLONG);
5708
5709         ret = btrfs_inode_by_name(dir, dentry, &location);
5710         if (ret < 0)
5711                 return ERR_PTR(ret);
5712
5713         if (location.type == BTRFS_INODE_ITEM_KEY) {
5714                 inode = btrfs_iget(dir->i_sb, &location, root, NULL);
5715                 return inode;
5716         }
5717
5718         index = srcu_read_lock(&fs_info->subvol_srcu);
5719         ret = fixup_tree_root_location(fs_info, dir, dentry,
5720                                        &location, &sub_root);
5721         if (ret < 0) {
5722                 if (ret != -ENOENT)
5723                         inode = ERR_PTR(ret);
5724                 else
5725                         inode = new_simple_dir(dir->i_sb, &location, sub_root);
5726         } else {
5727                 inode = btrfs_iget(dir->i_sb, &location, sub_root, NULL);
5728         }
5729         srcu_read_unlock(&fs_info->subvol_srcu, index);
5730
5731         if (!IS_ERR(inode) && root != sub_root) {
5732                 down_read(&fs_info->cleanup_work_sem);
5733                 if (!sb_rdonly(inode->i_sb))
5734                         ret = btrfs_orphan_cleanup(sub_root);
5735                 up_read(&fs_info->cleanup_work_sem);
5736                 if (ret) {
5737                         iput(inode);
5738                         inode = ERR_PTR(ret);
5739                 }
5740         }
5741
5742         return inode;
5743 }
5744
5745 static int btrfs_dentry_delete(const struct dentry *dentry)
5746 {
5747         struct btrfs_root *root;
5748         struct inode *inode = d_inode(dentry);
5749
5750         if (!inode && !IS_ROOT(dentry))
5751                 inode = d_inode(dentry->d_parent);
5752
5753         if (inode) {
5754                 root = BTRFS_I(inode)->root;
5755                 if (btrfs_root_refs(&root->root_item) == 0)
5756                         return 1;
5757
5758                 if (btrfs_ino(BTRFS_I(inode)) == BTRFS_EMPTY_SUBVOL_DIR_OBJECTID)
5759                         return 1;
5760         }
5761         return 0;
5762 }
5763
5764 static struct dentry *btrfs_lookup(struct inode *dir, struct dentry *dentry,
5765                                    unsigned int flags)
5766 {
5767         struct inode *inode;
5768
5769         inode = btrfs_lookup_dentry(dir, dentry);
5770         if (IS_ERR(inode)) {
5771                 if (PTR_ERR(inode) == -ENOENT)
5772                         inode = NULL;
5773                 else
5774                         return ERR_CAST(inode);
5775         }
5776
5777         return d_splice_alias(inode, dentry);
5778 }
5779
5780 unsigned char btrfs_filetype_table[] = {
5781         DT_UNKNOWN, DT_REG, DT_DIR, DT_CHR, DT_BLK, DT_FIFO, DT_SOCK, DT_LNK
5782 };
5783
5784 /*
5785  * All this infrastructure exists because dir_emit can fault, and we are holding
5786  * the tree lock when doing readdir.  For now just allocate a buffer and copy
5787  * our information into that, and then dir_emit from the buffer.  This is
5788  * similar to what NFS does, only we don't keep the buffer around in pagecache
5789  * because I'm afraid I'll mess that up.  Long term we need to make filldir do
5790  * copy_to_user_inatomic so we don't have to worry about page faulting under the
5791  * tree lock.
5792  */
5793 static int btrfs_opendir(struct inode *inode, struct file *file)
5794 {
5795         struct btrfs_file_private *private;
5796
5797         private = kzalloc(sizeof(struct btrfs_file_private), GFP_KERNEL);
5798         if (!private)
5799                 return -ENOMEM;
5800         private->filldir_buf = kzalloc(PAGE_SIZE, GFP_KERNEL);
5801         if (!private->filldir_buf) {
5802                 kfree(private);
5803                 return -ENOMEM;
5804         }
5805         file->private_data = private;
5806         return 0;
5807 }
5808
5809 struct dir_entry {
5810         u64 ino;
5811         u64 offset;
5812         unsigned type;
5813         int name_len;
5814 };
5815
5816 static int btrfs_filldir(void *addr, int entries, struct dir_context *ctx)
5817 {
5818         while (entries--) {
5819                 struct dir_entry *entry = addr;
5820                 char *name = (char *)(entry + 1);
5821
5822                 ctx->pos = get_unaligned(&entry->offset);
5823                 if (!dir_emit(ctx, name, get_unaligned(&entry->name_len),
5824                                          get_unaligned(&entry->ino),
5825                                          get_unaligned(&entry->type)))
5826                         return 1;
5827                 addr += sizeof(struct dir_entry) +
5828                         get_unaligned(&entry->name_len);
5829                 ctx->pos++;
5830         }
5831         return 0;
5832 }
5833
5834 static int btrfs_real_readdir(struct file *file, struct dir_context *ctx)
5835 {
5836         struct inode *inode = file_inode(file);
5837         struct btrfs_root *root = BTRFS_I(inode)->root;
5838         struct btrfs_file_private *private = file->private_data;
5839         struct btrfs_dir_item *di;
5840         struct btrfs_key key;
5841         struct btrfs_key found_key;
5842         struct btrfs_path *path;
5843         void *addr;
5844         struct list_head ins_list;
5845         struct list_head del_list;
5846         int ret;
5847         struct extent_buffer *leaf;
5848         int slot;
5849         char *name_ptr;
5850         int name_len;
5851         int entries = 0;
5852         int total_len = 0;
5853         bool put = false;
5854         struct btrfs_key location;
5855
5856         if (!dir_emit_dots(file, ctx))
5857                 return 0;
5858
5859         path = btrfs_alloc_path();
5860         if (!path)
5861                 return -ENOMEM;
5862
5863         addr = private->filldir_buf;
5864         path->reada = READA_FORWARD;
5865
5866         INIT_LIST_HEAD(&ins_list);
5867         INIT_LIST_HEAD(&del_list);
5868         put = btrfs_readdir_get_delayed_items(inode, &ins_list, &del_list);
5869
5870 again:
5871         key.type = BTRFS_DIR_INDEX_KEY;
5872         key.offset = ctx->pos;
5873         key.objectid = btrfs_ino(BTRFS_I(inode));
5874
5875         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
5876         if (ret < 0)
5877                 goto err;
5878
5879         while (1) {
5880                 struct dir_entry *entry;
5881
5882                 leaf = path->nodes[0];
5883                 slot = path->slots[0];
5884                 if (slot >= btrfs_header_nritems(leaf)) {
5885                         ret = btrfs_next_leaf(root, path);
5886                         if (ret < 0)
5887                                 goto err;
5888                         else if (ret > 0)
5889                                 break;
5890                         continue;
5891                 }
5892
5893                 btrfs_item_key_to_cpu(leaf, &found_key, slot);
5894
5895                 if (found_key.objectid != key.objectid)
5896                         break;
5897                 if (found_key.type != BTRFS_DIR_INDEX_KEY)
5898                         break;
5899                 if (found_key.offset < ctx->pos)
5900                         goto next;
5901                 if (btrfs_should_delete_dir_index(&del_list, found_key.offset))
5902                         goto next;
5903                 di = btrfs_item_ptr(leaf, slot, struct btrfs_dir_item);
5904                 name_len = btrfs_dir_name_len(leaf, di);
5905                 if ((total_len + sizeof(struct dir_entry) + name_len) >=
5906                     PAGE_SIZE) {
5907                         btrfs_release_path(path);
5908                         ret = btrfs_filldir(private->filldir_buf, entries, ctx);
5909                         if (ret)
5910                                 goto nopos;
5911                         addr = private->filldir_buf;
5912                         entries = 0;
5913                         total_len = 0;
5914                         goto again;
5915                 }
5916
5917                 entry = addr;
5918                 put_unaligned(name_len, &entry->name_len);
5919                 name_ptr = (char *)(entry + 1);
5920                 read_extent_buffer(leaf, name_ptr, (unsigned long)(di + 1),
5921                                    name_len);
5922                 put_unaligned(btrfs_filetype_table[btrfs_dir_type(leaf, di)],
5923                                 &entry->type);
5924                 btrfs_dir_item_key_to_cpu(leaf, di, &location);
5925                 put_unaligned(location.objectid, &entry->ino);
5926                 put_unaligned(found_key.offset, &entry->offset);
5927                 entries++;
5928                 addr += sizeof(struct dir_entry) + name_len;
5929                 total_len += sizeof(struct dir_entry) + name_len;
5930 next:
5931                 path->slots[0]++;
5932         }
5933         btrfs_release_path(path);
5934
5935         ret = btrfs_filldir(private->filldir_buf, entries, ctx);
5936         if (ret)
5937                 goto nopos;
5938
5939         ret = btrfs_readdir_delayed_dir_index(ctx, &ins_list);
5940         if (ret)
5941                 goto nopos;
5942
5943         /*
5944          * Stop new entries from being returned after we return the last
5945          * entry.
5946          *
5947          * New directory entries are assigned a strictly increasing
5948          * offset.  This means that new entries created during readdir
5949          * are *guaranteed* to be seen in the future by that readdir.
5950          * This has broken buggy programs which operate on names as
5951          * they're returned by readdir.  Until we re-use freed offsets
5952          * we have this hack to stop new entries from being returned
5953          * under the assumption that they'll never reach this huge
5954          * offset.
5955          *
5956          * This is being careful not to overflow 32bit loff_t unless the
5957          * last entry requires it because doing so has broken 32bit apps
5958          * in the past.
5959          */
5960         if (ctx->pos >= INT_MAX)
5961                 ctx->pos = LLONG_MAX;
5962         else
5963                 ctx->pos = INT_MAX;
5964 nopos:
5965         ret = 0;
5966 err:
5967         if (put)
5968                 btrfs_readdir_put_delayed_items(inode, &ins_list, &del_list);
5969         btrfs_free_path(path);
5970         return ret;
5971 }
5972
5973 /*
5974  * This is somewhat expensive, updating the tree every time the
5975  * inode changes.  But, it is most likely to find the inode in cache.
5976  * FIXME, needs more benchmarking...there are no reasons other than performance
5977  * to keep or drop this code.
5978  */
5979 static int btrfs_dirty_inode(struct inode *inode)
5980 {
5981         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
5982         struct btrfs_root *root = BTRFS_I(inode)->root;
5983         struct btrfs_trans_handle *trans;
5984         int ret;
5985
5986         if (test_bit(BTRFS_INODE_DUMMY, &BTRFS_I(inode)->runtime_flags))
5987                 return 0;
5988
5989         trans = btrfs_join_transaction(root);
5990         if (IS_ERR(trans))
5991                 return PTR_ERR(trans);
5992
5993         ret = btrfs_update_inode(trans, root, inode);
5994         if (ret && ret == -ENOSPC) {
5995                 /* whoops, lets try again with the full transaction */
5996                 btrfs_end_transaction(trans);
5997                 trans = btrfs_start_transaction(root, 1);
5998                 if (IS_ERR(trans))
5999                         return PTR_ERR(trans);
6000
6001                 ret = btrfs_update_inode(trans, root, inode);
6002         }
6003         btrfs_end_transaction(trans);
6004         if (BTRFS_I(inode)->delayed_node)
6005                 btrfs_balance_delayed_items(fs_info);
6006
6007         return ret;
6008 }
6009
6010 /*
6011  * This is a copy of file_update_time.  We need this so we can return error on
6012  * ENOSPC for updating the inode in the case of file write and mmap writes.
6013  */
6014 static int btrfs_update_time(struct inode *inode, struct timespec64 *now,
6015                              int flags)
6016 {
6017         struct btrfs_root *root = BTRFS_I(inode)->root;
6018         bool dirty = flags & ~S_VERSION;
6019
6020         if (btrfs_root_readonly(root))
6021                 return -EROFS;
6022
6023         if (flags & S_VERSION)
6024                 dirty |= inode_maybe_inc_iversion(inode, dirty);
6025         if (flags & S_CTIME)
6026                 inode->i_ctime = *now;
6027         if (flags & S_MTIME)
6028                 inode->i_mtime = *now;
6029         if (flags & S_ATIME)
6030                 inode->i_atime = *now;
6031         return dirty ? btrfs_dirty_inode(inode) : 0;
6032 }
6033
6034 /*
6035  * find the highest existing sequence number in a directory
6036  * and then set the in-memory index_cnt variable to reflect
6037  * free sequence numbers
6038  */
6039 static int btrfs_set_inode_index_count(struct btrfs_inode *inode)
6040 {
6041         struct btrfs_root *root = inode->root;
6042         struct btrfs_key key, found_key;
6043         struct btrfs_path *path;
6044         struct extent_buffer *leaf;
6045         int ret;
6046
6047         key.objectid = btrfs_ino(inode);
6048         key.type = BTRFS_DIR_INDEX_KEY;
6049         key.offset = (u64)-1;
6050
6051         path = btrfs_alloc_path();
6052         if (!path)
6053                 return -ENOMEM;
6054
6055         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
6056         if (ret < 0)
6057                 goto out;
6058         /* FIXME: we should be able to handle this */
6059         if (ret == 0)
6060                 goto out;
6061         ret = 0;
6062
6063         /*
6064          * MAGIC NUMBER EXPLANATION:
6065          * since we search a directory based on f_pos we have to start at 2
6066          * since '.' and '..' have f_pos of 0 and 1 respectively, so everybody
6067          * else has to start at 2
6068          */
6069         if (path->slots[0] == 0) {
6070                 inode->index_cnt = 2;
6071                 goto out;
6072         }
6073
6074         path->slots[0]--;
6075
6076         leaf = path->nodes[0];
6077         btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
6078
6079         if (found_key.objectid != btrfs_ino(inode) ||
6080             found_key.type != BTRFS_DIR_INDEX_KEY) {
6081                 inode->index_cnt = 2;
6082                 goto out;
6083         }
6084
6085         inode->index_cnt = found_key.offset + 1;
6086 out:
6087         btrfs_free_path(path);
6088         return ret;
6089 }
6090
6091 /*
6092  * helper to find a free sequence number in a given directory.  This current
6093  * code is very simple, later versions will do smarter things in the btree
6094  */
6095 int btrfs_set_inode_index(struct btrfs_inode *dir, u64 *index)
6096 {
6097         int ret = 0;
6098
6099         if (dir->index_cnt == (u64)-1) {
6100                 ret = btrfs_inode_delayed_dir_index_count(dir);
6101                 if (ret) {
6102                         ret = btrfs_set_inode_index_count(dir);
6103                         if (ret)
6104                                 return ret;
6105                 }
6106         }
6107
6108         *index = dir->index_cnt;
6109         dir->index_cnt++;
6110
6111         return ret;
6112 }
6113
6114 static int btrfs_insert_inode_locked(struct inode *inode)
6115 {
6116         struct btrfs_iget_args args;
6117         args.location = &BTRFS_I(inode)->location;
6118         args.root = BTRFS_I(inode)->root;
6119
6120         return insert_inode_locked4(inode,
6121                    btrfs_inode_hash(inode->i_ino, BTRFS_I(inode)->root),
6122                    btrfs_find_actor, &args);
6123 }
6124
6125 /*
6126  * Inherit flags from the parent inode.
6127  *
6128  * Currently only the compression flags and the cow flags are inherited.
6129  */
6130 static void btrfs_inherit_iflags(struct inode *inode, struct inode *dir)
6131 {
6132         unsigned int flags;
6133
6134         if (!dir)
6135                 return;
6136
6137         flags = BTRFS_I(dir)->flags;
6138
6139         if (flags & BTRFS_INODE_NOCOMPRESS) {
6140                 BTRFS_I(inode)->flags &= ~BTRFS_INODE_COMPRESS;
6141                 BTRFS_I(inode)->flags |= BTRFS_INODE_NOCOMPRESS;
6142         } else if (flags & BTRFS_INODE_COMPRESS) {
6143                 BTRFS_I(inode)->flags &= ~BTRFS_INODE_NOCOMPRESS;
6144                 BTRFS_I(inode)->flags |= BTRFS_INODE_COMPRESS;
6145         }
6146
6147         if (flags & BTRFS_INODE_NODATACOW) {
6148                 BTRFS_I(inode)->flags |= BTRFS_INODE_NODATACOW;
6149                 if (S_ISREG(inode->i_mode))
6150                         BTRFS_I(inode)->flags |= BTRFS_INODE_NODATASUM;
6151         }
6152
6153         btrfs_sync_inode_flags_to_i_flags(inode);
6154 }
6155
6156 static struct inode *btrfs_new_inode(struct btrfs_trans_handle *trans,
6157                                      struct btrfs_root *root,
6158                                      struct inode *dir,
6159                                      const char *name, int name_len,
6160                                      u64 ref_objectid, u64 objectid,
6161                                      umode_t mode, u64 *index)
6162 {
6163         struct btrfs_fs_info *fs_info = root->fs_info;
6164         struct inode *inode;
6165         struct btrfs_inode_item *inode_item;
6166         struct btrfs_key *location;
6167         struct btrfs_path *path;
6168         struct btrfs_inode_ref *ref;
6169         struct btrfs_key key[2];
6170         u32 sizes[2];
6171         int nitems = name ? 2 : 1;
6172         unsigned long ptr;
6173         int ret;
6174
6175         path = btrfs_alloc_path();
6176         if (!path)
6177                 return ERR_PTR(-ENOMEM);
6178
6179         inode = new_inode(fs_info->sb);
6180         if (!inode) {
6181                 btrfs_free_path(path);
6182                 return ERR_PTR(-ENOMEM);
6183         }
6184
6185         /*
6186          * O_TMPFILE, set link count to 0, so that after this point,
6187          * we fill in an inode item with the correct link count.
6188          */
6189         if (!name)
6190                 set_nlink(inode, 0);
6191
6192         /*
6193          * we have to initialize this early, so we can reclaim the inode
6194          * number if we fail afterwards in this function.
6195          */
6196         inode->i_ino = objectid;
6197
6198         if (dir && name) {
6199                 trace_btrfs_inode_request(dir);
6200
6201                 ret = btrfs_set_inode_index(BTRFS_I(dir), index);
6202                 if (ret) {
6203                         btrfs_free_path(path);
6204                         iput(inode);
6205                         return ERR_PTR(ret);
6206                 }
6207         } else if (dir) {
6208                 *index = 0;
6209         }
6210         /*
6211          * index_cnt is ignored for everything but a dir,
6212          * btrfs_set_inode_index_count has an explanation for the magic
6213          * number
6214          */
6215         BTRFS_I(inode)->index_cnt = 2;
6216         BTRFS_I(inode)->dir_index = *index;
6217         BTRFS_I(inode)->root = root;
6218         BTRFS_I(inode)->generation = trans->transid;
6219         inode->i_generation = BTRFS_I(inode)->generation;
6220
6221         /*
6222          * We could have gotten an inode number from somebody who was fsynced
6223          * and then removed in this same transaction, so let's just set full
6224          * sync since it will be a full sync anyway and this will blow away the
6225          * old info in the log.
6226          */
6227         set_bit(BTRFS_INODE_NEEDS_FULL_SYNC, &BTRFS_I(inode)->runtime_flags);
6228
6229         key[0].objectid = objectid;
6230         key[0].type = BTRFS_INODE_ITEM_KEY;
6231         key[0].offset = 0;
6232
6233         sizes[0] = sizeof(struct btrfs_inode_item);
6234
6235         if (name) {
6236                 /*
6237                  * Start new inodes with an inode_ref. This is slightly more
6238                  * efficient for small numbers of hard links since they will
6239                  * be packed into one item. Extended refs will kick in if we
6240                  * add more hard links than can fit in the ref item.
6241                  */
6242                 key[1].objectid = objectid;
6243                 key[1].type = BTRFS_INODE_REF_KEY;
6244                 key[1].offset = ref_objectid;
6245
6246                 sizes[1] = name_len + sizeof(*ref);
6247         }
6248
6249         location = &BTRFS_I(inode)->location;
6250         location->objectid = objectid;
6251         location->offset = 0;
6252         location->type = BTRFS_INODE_ITEM_KEY;
6253
6254         ret = btrfs_insert_inode_locked(inode);
6255         if (ret < 0) {
6256                 iput(inode);
6257                 goto fail;
6258         }
6259
6260         path->leave_spinning = 1;
6261         ret = btrfs_insert_empty_items(trans, root, path, key, sizes, nitems);
6262         if (ret != 0)
6263                 goto fail_unlock;
6264
6265         inode_init_owner(inode, dir, mode);
6266         inode_set_bytes(inode, 0);
6267
6268         inode->i_mtime = current_time(inode);
6269         inode->i_atime = inode->i_mtime;
6270         inode->i_ctime = inode->i_mtime;
6271         BTRFS_I(inode)->i_otime = inode->i_mtime;
6272
6273         inode_item = btrfs_item_ptr(path->nodes[0], path->slots[0],
6274                                   struct btrfs_inode_item);
6275         memzero_extent_buffer(path->nodes[0], (unsigned long)inode_item,
6276                              sizeof(*inode_item));
6277         fill_inode_item(trans, path->nodes[0], inode_item, inode);
6278
6279         if (name) {
6280                 ref = btrfs_item_ptr(path->nodes[0], path->slots[0] + 1,
6281                                      struct btrfs_inode_ref);
6282                 btrfs_set_inode_ref_name_len(path->nodes[0], ref, name_len);
6283                 btrfs_set_inode_ref_index(path->nodes[0], ref, *index);
6284                 ptr = (unsigned long)(ref + 1);
6285                 write_extent_buffer(path->nodes[0], name, ptr, name_len);
6286         }
6287
6288         btrfs_mark_buffer_dirty(path->nodes[0]);
6289         btrfs_free_path(path);
6290
6291         btrfs_inherit_iflags(inode, dir);
6292
6293         if (S_ISREG(mode)) {
6294                 if (btrfs_test_opt(fs_info, NODATASUM))
6295                         BTRFS_I(inode)->flags |= BTRFS_INODE_NODATASUM;
6296                 if (btrfs_test_opt(fs_info, NODATACOW))
6297                         BTRFS_I(inode)->flags |= BTRFS_INODE_NODATACOW |
6298                                 BTRFS_INODE_NODATASUM;
6299         }
6300
6301         inode_tree_add(inode);
6302
6303         trace_btrfs_inode_new(inode);
6304         btrfs_set_inode_last_trans(trans, inode);
6305
6306         btrfs_update_root_times(trans, root);
6307
6308         ret = btrfs_inode_inherit_props(trans, inode, dir);
6309         if (ret)
6310                 btrfs_err(fs_info,
6311                           "error inheriting props for ino %llu (root %llu): %d",
6312                         btrfs_ino(BTRFS_I(inode)), root->root_key.objectid, ret);
6313
6314         return inode;
6315
6316 fail_unlock:
6317         discard_new_inode(inode);
6318 fail:
6319         if (dir && name)
6320                 BTRFS_I(dir)->index_cnt--;
6321         btrfs_free_path(path);
6322         return ERR_PTR(ret);
6323 }
6324
6325 static inline u8 btrfs_inode_type(struct inode *inode)
6326 {
6327         return btrfs_type_by_mode[(inode->i_mode & S_IFMT) >> S_SHIFT];
6328 }
6329
6330 /*
6331  * utility function to add 'inode' into 'parent_inode' with
6332  * a give name and a given sequence number.
6333  * if 'add_backref' is true, also insert a backref from the
6334  * inode to the parent directory.
6335  */
6336 int btrfs_add_link(struct btrfs_trans_handle *trans,
6337                    struct btrfs_inode *parent_inode, struct btrfs_inode *inode,
6338                    const char *name, int name_len, int add_backref, u64 index)
6339 {
6340         int ret = 0;
6341         struct btrfs_key key;
6342         struct btrfs_root *root = parent_inode->root;
6343         u64 ino = btrfs_ino(inode);
6344         u64 parent_ino = btrfs_ino(parent_inode);
6345
6346         if (unlikely(ino == BTRFS_FIRST_FREE_OBJECTID)) {
6347                 memcpy(&key, &inode->root->root_key, sizeof(key));
6348         } else {
6349                 key.objectid = ino;
6350                 key.type = BTRFS_INODE_ITEM_KEY;
6351                 key.offset = 0;
6352         }
6353
6354         if (unlikely(ino == BTRFS_FIRST_FREE_OBJECTID)) {
6355                 ret = btrfs_add_root_ref(trans, key.objectid,
6356                                          root->root_key.objectid, parent_ino,
6357                                          index, name, name_len);
6358         } else if (add_backref) {
6359                 ret = btrfs_insert_inode_ref(trans, root, name, name_len, ino,
6360                                              parent_ino, index);
6361         }
6362
6363         /* Nothing to clean up yet */
6364         if (ret)
6365                 return ret;
6366
6367         ret = btrfs_insert_dir_item(trans, name, name_len, parent_inode, &key,
6368                                     btrfs_inode_type(&inode->vfs_inode), index);
6369         if (ret == -EEXIST || ret == -EOVERFLOW)
6370                 goto fail_dir_item;
6371         else if (ret) {
6372                 btrfs_abort_transaction(trans, ret);
6373                 return ret;
6374         }
6375
6376         btrfs_i_size_write(parent_inode, parent_inode->vfs_inode.i_size +
6377                            name_len * 2);
6378         inode_inc_iversion(&parent_inode->vfs_inode);
6379         parent_inode->vfs_inode.i_mtime = parent_inode->vfs_inode.i_ctime =
6380                 current_time(&parent_inode->vfs_inode);
6381         ret = btrfs_update_inode(trans, root, &parent_inode->vfs_inode);
6382         if (ret)
6383                 btrfs_abort_transaction(trans, ret);
6384         return ret;
6385
6386 fail_dir_item:
6387         if (unlikely(ino == BTRFS_FIRST_FREE_OBJECTID)) {
6388                 u64 local_index;
6389                 int err;
6390                 err = btrfs_del_root_ref(trans, key.objectid,
6391                                          root->root_key.objectid, parent_ino,
6392                                          &local_index, name, name_len);
6393
6394         } else if (add_backref) {
6395                 u64 local_index;
6396                 int err;
6397
6398                 err = btrfs_del_inode_ref(trans, root, name, name_len,
6399                                           ino, parent_ino, &local_index);
6400         }
6401         return ret;
6402 }
6403
6404 static int btrfs_add_nondir(struct btrfs_trans_handle *trans,
6405                             struct btrfs_inode *dir, struct dentry *dentry,
6406                             struct btrfs_inode *inode, int backref, u64 index)
6407 {
6408         int err = btrfs_add_link(trans, dir, inode,
6409                                  dentry->d_name.name, dentry->d_name.len,
6410                                  backref, index);
6411         if (err > 0)
6412                 err = -EEXIST;
6413         return err;
6414 }
6415
6416 static int btrfs_mknod(struct inode *dir, struct dentry *dentry,
6417                         umode_t mode, dev_t rdev)
6418 {
6419         struct btrfs_fs_info *fs_info = btrfs_sb(dir->i_sb);
6420         struct btrfs_trans_handle *trans;
6421         struct btrfs_root *root = BTRFS_I(dir)->root;
6422         struct inode *inode = NULL;
6423         int err;
6424         u64 objectid;
6425         u64 index = 0;
6426
6427         /*
6428          * 2 for inode item and ref
6429          * 2 for dir items
6430          * 1 for xattr if selinux is on
6431          */
6432         trans = btrfs_start_transaction(root, 5);
6433         if (IS_ERR(trans))
6434                 return PTR_ERR(trans);
6435
6436         err = btrfs_find_free_ino(root, &objectid);
6437         if (err)
6438                 goto out_unlock;
6439
6440         inode = btrfs_new_inode(trans, root, dir, dentry->d_name.name,
6441                         dentry->d_name.len, btrfs_ino(BTRFS_I(dir)), objectid,
6442                         mode, &index);
6443         if (IS_ERR(inode)) {
6444                 err = PTR_ERR(inode);
6445                 inode = NULL;
6446                 goto out_unlock;
6447         }
6448
6449         /*
6450         * If the active LSM wants to access the inode during
6451         * d_instantiate it needs these. Smack checks to see
6452         * if the filesystem supports xattrs by looking at the
6453         * ops vector.
6454         */
6455         inode->i_op = &btrfs_special_inode_operations;
6456         init_special_inode(inode, inode->i_mode, rdev);
6457
6458         err = btrfs_init_inode_security(trans, inode, dir, &dentry->d_name);
6459         if (err)
6460                 goto out_unlock;
6461
6462         err = btrfs_add_nondir(trans, BTRFS_I(dir), dentry, BTRFS_I(inode),
6463                         0, index);
6464         if (err)
6465                 goto out_unlock;
6466
6467         btrfs_update_inode(trans, root, inode);
6468         d_instantiate_new(dentry, inode);
6469
6470 out_unlock:
6471         btrfs_end_transaction(trans);
6472         btrfs_btree_balance_dirty(fs_info);
6473         if (err && inode) {
6474                 inode_dec_link_count(inode);
6475                 discard_new_inode(inode);
6476         }
6477         return err;
6478 }
6479
6480 static int btrfs_create(struct inode *dir, struct dentry *dentry,
6481                         umode_t mode, bool excl)
6482 {
6483         struct btrfs_fs_info *fs_info = btrfs_sb(dir->i_sb);
6484         struct btrfs_trans_handle *trans;
6485         struct btrfs_root *root = BTRFS_I(dir)->root;
6486         struct inode *inode = NULL;
6487         int err;
6488         u64 objectid;
6489         u64 index = 0;
6490
6491         /*
6492          * 2 for inode item and ref
6493          * 2 for dir items
6494          * 1 for xattr if selinux is on
6495          */
6496         trans = btrfs_start_transaction(root, 5);
6497         if (IS_ERR(trans))
6498                 return PTR_ERR(trans);
6499
6500         err = btrfs_find_free_ino(root, &objectid);
6501         if (err)
6502                 goto out_unlock;
6503
6504         inode = btrfs_new_inode(trans, root, dir, dentry->d_name.name,
6505                         dentry->d_name.len, btrfs_ino(BTRFS_I(dir)), objectid,
6506                         mode, &index);
6507         if (IS_ERR(inode)) {
6508                 err = PTR_ERR(inode);
6509                 inode = NULL;
6510                 goto out_unlock;
6511         }
6512         /*
6513         * If the active LSM wants to access the inode during
6514         * d_instantiate it needs these. Smack checks to see
6515         * if the filesystem supports xattrs by looking at the
6516         * ops vector.
6517         */
6518         inode->i_fop = &btrfs_file_operations;
6519         inode->i_op = &btrfs_file_inode_operations;
6520         inode->i_mapping->a_ops = &btrfs_aops;
6521
6522         err = btrfs_init_inode_security(trans, inode, dir, &dentry->d_name);
6523         if (err)
6524                 goto out_unlock;
6525
6526         err = btrfs_update_inode(trans, root, inode);
6527         if (err)
6528                 goto out_unlock;
6529
6530         err = btrfs_add_nondir(trans, BTRFS_I(dir), dentry, BTRFS_I(inode),
6531                         0, index);
6532         if (err)
6533                 goto out_unlock;
6534
6535         BTRFS_I(inode)->io_tree.ops = &btrfs_extent_io_ops;
6536         d_instantiate_new(dentry, inode);
6537
6538 out_unlock:
6539         btrfs_end_transaction(trans);
6540         if (err && inode) {
6541                 inode_dec_link_count(inode);
6542                 discard_new_inode(inode);
6543         }
6544         btrfs_btree_balance_dirty(fs_info);
6545         return err;
6546 }
6547
6548 static int btrfs_link(struct dentry *old_dentry, struct inode *dir,
6549                       struct dentry *dentry)
6550 {
6551         struct btrfs_trans_handle *trans = NULL;
6552         struct btrfs_root *root = BTRFS_I(dir)->root;
6553         struct inode *inode = d_inode(old_dentry);
6554         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
6555         u64 index;
6556         int err;
6557         int drop_inode = 0;
6558
6559         /* do not allow sys_link's with other subvols of the same device */
6560         if (root->root_key.objectid != BTRFS_I(inode)->root->root_key.objectid)
6561                 return -EXDEV;
6562
6563         if (inode->i_nlink >= BTRFS_LINK_MAX)
6564                 return -EMLINK;
6565
6566         err = btrfs_set_inode_index(BTRFS_I(dir), &index);
6567         if (err)
6568                 goto fail;
6569
6570         /*
6571          * 2 items for inode and inode ref
6572          * 2 items for dir items
6573          * 1 item for parent inode
6574          * 1 item for orphan item deletion if O_TMPFILE
6575          */
6576         trans = btrfs_start_transaction(root, inode->i_nlink ? 5 : 6);
6577         if (IS_ERR(trans)) {
6578                 err = PTR_ERR(trans);
6579                 trans = NULL;
6580                 goto fail;
6581         }
6582
6583         /* There are several dir indexes for this inode, clear the cache. */
6584         BTRFS_I(inode)->dir_index = 0ULL;
6585         inc_nlink(inode);
6586         inode_inc_iversion(inode);
6587         inode->i_ctime = current_time(inode);
6588         ihold(inode);
6589         set_bit(BTRFS_INODE_COPY_EVERYTHING, &BTRFS_I(inode)->runtime_flags);
6590
6591         err = btrfs_add_nondir(trans, BTRFS_I(dir), dentry, BTRFS_I(inode),
6592                         1, index);
6593
6594         if (err) {
6595                 drop_inode = 1;
6596         } else {
6597                 struct dentry *parent = dentry->d_parent;
6598                 int ret;
6599
6600                 err = btrfs_update_inode(trans, root, inode);
6601                 if (err)
6602                         goto fail;
6603                 if (inode->i_nlink == 1) {
6604                         /*
6605                          * If new hard link count is 1, it's a file created
6606                          * with open(2) O_TMPFILE flag.
6607                          */
6608                         err = btrfs_orphan_del(trans, BTRFS_I(inode));
6609                         if (err)
6610                                 goto fail;
6611                 }
6612                 d_instantiate(dentry, inode);
6613                 ret = btrfs_log_new_name(trans, BTRFS_I(inode), NULL, parent,
6614                                          true, NULL);
6615                 if (ret == BTRFS_NEED_TRANS_COMMIT) {
6616                         err = btrfs_commit_transaction(trans);
6617                         trans = NULL;
6618                 }
6619         }
6620
6621 fail:
6622         if (trans)
6623                 btrfs_end_transaction(trans);
6624         if (drop_inode) {
6625                 inode_dec_link_count(inode);
6626                 iput(inode);
6627         }
6628         btrfs_btree_balance_dirty(fs_info);
6629         return err;
6630 }
6631
6632 static int btrfs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
6633 {
6634         struct btrfs_fs_info *fs_info = btrfs_sb(dir->i_sb);
6635         struct inode *inode = NULL;
6636         struct btrfs_trans_handle *trans;
6637         struct btrfs_root *root = BTRFS_I(dir)->root;
6638         int err = 0;
6639         int drop_on_err = 0;
6640         u64 objectid = 0;
6641         u64 index = 0;
6642
6643         /*
6644          * 2 items for inode and ref
6645          * 2 items for dir items
6646          * 1 for xattr if selinux is on
6647          */
6648         trans = btrfs_start_transaction(root, 5);
6649         if (IS_ERR(trans))
6650                 return PTR_ERR(trans);
6651
6652         err = btrfs_find_free_ino(root, &objectid);
6653         if (err)
6654                 goto out_fail;
6655
6656         inode = btrfs_new_inode(trans, root, dir, dentry->d_name.name,
6657                         dentry->d_name.len, btrfs_ino(BTRFS_I(dir)), objectid,
6658                         S_IFDIR | mode, &index);
6659         if (IS_ERR(inode)) {
6660                 err = PTR_ERR(inode);
6661                 inode = NULL;
6662                 goto out_fail;
6663         }
6664
6665         drop_on_err = 1;
6666         /* these must be set before we unlock the inode */
6667         inode->i_op = &btrfs_dir_inode_operations;
6668         inode->i_fop = &btrfs_dir_file_operations;
6669
6670         err = btrfs_init_inode_security(trans, inode, dir, &dentry->d_name);
6671         if (err)
6672                 goto out_fail;
6673
6674         btrfs_i_size_write(BTRFS_I(inode), 0);
6675         err = btrfs_update_inode(trans, root, inode);
6676         if (err)
6677                 goto out_fail;
6678
6679         err = btrfs_add_link(trans, BTRFS_I(dir), BTRFS_I(inode),
6680                         dentry->d_name.name,
6681                         dentry->d_name.len, 0, index);
6682         if (err)
6683                 goto out_fail;
6684
6685         d_instantiate_new(dentry, inode);
6686         drop_on_err = 0;
6687
6688 out_fail:
6689         btrfs_end_transaction(trans);
6690         if (err && inode) {
6691                 inode_dec_link_count(inode);
6692                 discard_new_inode(inode);
6693         }
6694         btrfs_btree_balance_dirty(fs_info);
6695         return err;
6696 }
6697
6698 static noinline int uncompress_inline(struct btrfs_path *path,
6699                                       struct page *page,
6700                                       size_t pg_offset, u64 extent_offset,
6701                                       struct btrfs_file_extent_item *item)
6702 {
6703         int ret;
6704         struct extent_buffer *leaf = path->nodes[0];
6705         char *tmp;
6706         size_t max_size;
6707         unsigned long inline_size;
6708         unsigned long ptr;
6709         int compress_type;
6710
6711         WARN_ON(pg_offset != 0);
6712         compress_type = btrfs_file_extent_compression(leaf, item);
6713         max_size = btrfs_file_extent_ram_bytes(leaf, item);
6714         inline_size = btrfs_file_extent_inline_item_len(leaf,
6715                                         btrfs_item_nr(path->slots[0]));
6716         tmp = kmalloc(inline_size, GFP_NOFS);
6717         if (!tmp)
6718                 return -ENOMEM;
6719         ptr = btrfs_file_extent_inline_start(item);
6720
6721         read_extent_buffer(leaf, tmp, ptr, inline_size);
6722
6723         max_size = min_t(unsigned long, PAGE_SIZE, max_size);
6724         ret = btrfs_decompress(compress_type, tmp, page,
6725                                extent_offset, inline_size, max_size);
6726
6727         /*
6728          * decompression code contains a memset to fill in any space between the end
6729          * of the uncompressed data and the end of max_size in case the decompressed
6730          * data ends up shorter than ram_bytes.  That doesn't cover the hole between
6731          * the end of an inline extent and the beginning of the next block, so we
6732          * cover that region here.
6733          */
6734
6735         if (max_size + pg_offset < PAGE_SIZE) {
6736                 char *map = kmap(page);
6737                 memset(map + pg_offset + max_size, 0, PAGE_SIZE - max_size - pg_offset);
6738                 kunmap(page);
6739         }
6740         kfree(tmp);
6741         return ret;
6742 }
6743
6744 /*
6745  * a bit scary, this does extent mapping from logical file offset to the disk.
6746  * the ugly parts come from merging extents from the disk with the in-ram
6747  * representation.  This gets more complex because of the data=ordered code,
6748  * where the in-ram extents might be locked pending data=ordered completion.
6749  *
6750  * This also copies inline extents directly into the page.
6751  */
6752 struct extent_map *btrfs_get_extent(struct btrfs_inode *inode,
6753                                     struct page *page,
6754                                     size_t pg_offset, u64 start, u64 len,
6755                                     int create)
6756 {
6757         struct btrfs_fs_info *fs_info = inode->root->fs_info;
6758         int ret;
6759         int err = 0;
6760         u64 extent_start = 0;
6761         u64 extent_end = 0;
6762         u64 objectid = btrfs_ino(inode);
6763         u32 found_type;
6764         struct btrfs_path *path = NULL;
6765         struct btrfs_root *root = inode->root;
6766         struct btrfs_file_extent_item *item;
6767         struct extent_buffer *leaf;
6768         struct btrfs_key found_key;
6769         struct extent_map *em = NULL;
6770         struct extent_map_tree *em_tree = &inode->extent_tree;
6771         struct extent_io_tree *io_tree = &inode->io_tree;
6772         const bool new_inline = !page || create;
6773
6774         read_lock(&em_tree->lock);
6775         em = lookup_extent_mapping(em_tree, start, len);
6776         if (em)
6777                 em->bdev = fs_info->fs_devices->latest_bdev;
6778         read_unlock(&em_tree->lock);
6779
6780         if (em) {
6781                 if (em->start > start || em->start + em->len <= start)
6782                         free_extent_map(em);
6783                 else if (em->block_start == EXTENT_MAP_INLINE && page)
6784                         free_extent_map(em);
6785                 else
6786                         goto out;
6787         }
6788         em = alloc_extent_map();
6789         if (!em) {
6790                 err = -ENOMEM;
6791                 goto out;
6792         }
6793         em->bdev = fs_info->fs_devices->latest_bdev;
6794         em->start = EXTENT_MAP_HOLE;
6795         em->orig_start = EXTENT_MAP_HOLE;
6796         em->len = (u64)-1;
6797         em->block_len = (u64)-1;
6798
6799         path = btrfs_alloc_path();
6800         if (!path) {
6801                 err = -ENOMEM;
6802                 goto out;
6803         }
6804
6805         /* Chances are we'll be called again, so go ahead and do readahead */
6806         path->reada = READA_FORWARD;
6807
6808         /*
6809          * Unless we're going to uncompress the inline extent, no sleep would
6810          * happen.
6811          */
6812         path->leave_spinning = 1;
6813
6814         ret = btrfs_lookup_file_extent(NULL, root, path, objectid, start, 0);
6815         if (ret < 0) {
6816                 err = ret;
6817                 goto out;
6818         }
6819
6820         if (ret != 0) {
6821                 if (path->slots[0] == 0)
6822                         goto not_found;
6823                 path->slots[0]--;
6824         }
6825
6826         leaf = path->nodes[0];
6827         item = btrfs_item_ptr(leaf, path->slots[0],
6828                               struct btrfs_file_extent_item);
6829         /* are we inside the extent that was found? */
6830         btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
6831         found_type = found_key.type;
6832         if (found_key.objectid != objectid ||
6833             found_type != BTRFS_EXTENT_DATA_KEY) {
6834                 /*
6835                  * If we backup past the first extent we want to move forward
6836                  * and see if there is an extent in front of us, otherwise we'll
6837                  * say there is a hole for our whole search range which can
6838                  * cause problems.
6839                  */
6840                 extent_end = start;
6841                 goto next;
6842         }
6843
6844         found_type = btrfs_file_extent_type(leaf, item);
6845         extent_start = found_key.offset;
6846         if (found_type == BTRFS_FILE_EXTENT_REG ||
6847             found_type == BTRFS_FILE_EXTENT_PREALLOC) {
6848                 extent_end = extent_start +
6849                        btrfs_file_extent_num_bytes(leaf, item);
6850
6851                 trace_btrfs_get_extent_show_fi_regular(inode, leaf, item,
6852                                                        extent_start);
6853         } else if (found_type == BTRFS_FILE_EXTENT_INLINE) {
6854                 size_t size;
6855
6856                 size = btrfs_file_extent_ram_bytes(leaf, item);
6857                 extent_end = ALIGN(extent_start + size,
6858                                    fs_info->sectorsize);
6859
6860                 trace_btrfs_get_extent_show_fi_inline(inode, leaf, item,
6861                                                       path->slots[0],
6862                                                       extent_start);
6863         }
6864 next:
6865         if (start >= extent_end) {
6866                 path->slots[0]++;
6867                 if (path->slots[0] >= btrfs_header_nritems(leaf)) {
6868                         ret = btrfs_next_leaf(root, path);
6869                         if (ret < 0) {
6870                                 err = ret;
6871                                 goto out;
6872                         }
6873                         if (ret > 0)
6874                                 goto not_found;
6875                         leaf = path->nodes[0];
6876                 }
6877                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
6878                 if (found_key.objectid != objectid ||
6879                     found_key.type != BTRFS_EXTENT_DATA_KEY)
6880                         goto not_found;
6881                 if (start + len <= found_key.offset)
6882                         goto not_found;
6883                 if (start > found_key.offset)
6884                         goto next;
6885                 em->start = start;
6886                 em->orig_start = start;
6887                 em->len = found_key.offset - start;
6888                 goto not_found_em;
6889         }
6890
6891         btrfs_extent_item_to_extent_map(inode, path, item,
6892                         new_inline, em);
6893
6894         if (found_type == BTRFS_FILE_EXTENT_REG ||
6895             found_type == BTRFS_FILE_EXTENT_PREALLOC) {
6896                 goto insert;
6897         } else if (found_type == BTRFS_FILE_EXTENT_INLINE) {
6898                 unsigned long ptr;
6899                 char *map;
6900                 size_t size;
6901                 size_t extent_offset;
6902                 size_t copy_size;
6903
6904                 if (new_inline)
6905                         goto out;
6906
6907                 size = btrfs_file_extent_ram_bytes(leaf, item);
6908                 extent_offset = page_offset(page) + pg_offset - extent_start;
6909                 copy_size = min_t(u64, PAGE_SIZE - pg_offset,
6910                                   size - extent_offset);
6911                 em->start = extent_start + extent_offset;
6912                 em->len = ALIGN(copy_size, fs_info->sectorsize);
6913                 em->orig_block_len = em->len;
6914                 em->orig_start = em->start;
6915                 ptr = btrfs_file_extent_inline_start(item) + extent_offset;
6916
6917                 btrfs_set_path_blocking(path);
6918                 if (!PageUptodate(page)) {
6919                         if (btrfs_file_extent_compression(leaf, item) !=
6920                             BTRFS_COMPRESS_NONE) {
6921                                 ret = uncompress_inline(path, page, pg_offset,
6922                                                         extent_offset, item);
6923                                 if (ret) {
6924                                         err = ret;
6925                                         goto out;
6926                                 }
6927                         } else {
6928                                 map = kmap(page);
6929                                 read_extent_buffer(leaf, map + pg_offset, ptr,
6930                                                    copy_size);
6931                                 if (pg_offset + copy_size < PAGE_SIZE) {
6932                                         memset(map + pg_offset + copy_size, 0,
6933                                                PAGE_SIZE - pg_offset -
6934                                                copy_size);
6935                                 }
6936                                 kunmap(page);
6937                         }
6938                         flush_dcache_page(page);
6939                 }
6940                 set_extent_uptodate(io_tree, em->start,
6941                                     extent_map_end(em) - 1, NULL, GFP_NOFS);
6942                 goto insert;
6943         }
6944 not_found:
6945         em->start = start;
6946         em->orig_start = start;
6947         em->len = len;
6948 not_found_em:
6949         em->block_start = EXTENT_MAP_HOLE;
6950 insert:
6951         btrfs_release_path(path);
6952         if (em->start > start || extent_map_end(em) <= start) {
6953                 btrfs_err(fs_info,
6954                           "bad extent! em: [%llu %llu] passed [%llu %llu]",
6955                           em->start, em->len, start, len);
6956                 err = -EIO;
6957                 goto out;
6958         }
6959
6960         err = 0;
6961         write_lock(&em_tree->lock);
6962         err = btrfs_add_extent_mapping(fs_info, em_tree, &em, start, len);
6963         write_unlock(&em_tree->lock);
6964 out:
6965         btrfs_free_path(path);
6966
6967         trace_btrfs_get_extent(root, inode, em);
6968
6969         if (err) {
6970                 free_extent_map(em);
6971                 return ERR_PTR(err);
6972         }
6973         BUG_ON(!em); /* Error is always set */
6974         return em;
6975 }
6976
6977 struct extent_map *btrfs_get_extent_fiemap(struct btrfs_inode *inode,
6978                 struct page *page,
6979                 size_t pg_offset, u64 start, u64 len,
6980                 int create)
6981 {
6982         struct extent_map *em;
6983         struct extent_map *hole_em = NULL;
6984         u64 range_start = start;
6985         u64 end;
6986         u64 found;
6987         u64 found_end;
6988         int err = 0;
6989
6990         em = btrfs_get_extent(inode, page, pg_offset, start, len, create);
6991         if (IS_ERR(em))
6992                 return em;
6993         /*
6994          * If our em maps to:
6995          * - a hole or
6996          * - a pre-alloc extent,
6997          * there might actually be delalloc bytes behind it.
6998          */
6999         if (em->block_start != EXTENT_MAP_HOLE &&
7000             !test_bit(EXTENT_FLAG_PREALLOC, &em->flags))
7001                 return em;
7002         else
7003                 hole_em = em;
7004
7005         /* check to see if we've wrapped (len == -1 or similar) */
7006         end = start + len;
7007         if (end < start)
7008                 end = (u64)-1;
7009         else
7010                 end -= 1;
7011
7012         em = NULL;
7013
7014         /* ok, we didn't find anything, lets look for delalloc */
7015         found = count_range_bits(&inode->io_tree, &range_start,
7016                                  end, len, EXTENT_DELALLOC, 1);
7017         found_end = range_start + found;
7018         if (found_end < range_start)
7019                 found_end = (u64)-1;
7020
7021         /*
7022          * we didn't find anything useful, return
7023          * the original results from get_extent()
7024          */
7025         if (range_start > end || found_end <= start) {
7026                 em = hole_em;
7027                 hole_em = NULL;
7028                 goto out;
7029         }
7030
7031         /* adjust the range_start to make sure it doesn't
7032          * go backwards from the start they passed in
7033          */
7034         range_start = max(start, range_start);
7035         found = found_end - range_start;
7036
7037         if (found > 0) {
7038                 u64 hole_start = start;
7039                 u64 hole_len = len;
7040
7041                 em = alloc_extent_map();
7042                 if (!em) {
7043                         err = -ENOMEM;
7044                         goto out;
7045                 }
7046                 /*
7047                  * when btrfs_get_extent can't find anything it
7048                  * returns one huge hole
7049                  *
7050                  * make sure what it found really fits our range, and
7051                  * adjust to make sure it is based on the start from
7052                  * the caller
7053                  */
7054                 if (hole_em) {
7055                         u64 calc_end = extent_map_end(hole_em);
7056
7057                         if (calc_end <= start || (hole_em->start > end)) {
7058                                 free_extent_map(hole_em);
7059                                 hole_em = NULL;
7060                         } else {
7061                                 hole_start = max(hole_em->start, start);
7062                                 hole_len = calc_end - hole_start;
7063                         }
7064                 }
7065                 em->bdev = NULL;
7066                 if (hole_em && range_start > hole_start) {
7067                         /* our hole starts before our delalloc, so we
7068                          * have to return just the parts of the hole
7069                          * that go until  the delalloc starts
7070                          */
7071                         em->len = min(hole_len,
7072                                       range_start - hole_start);
7073                         em->start = hole_start;
7074                         em->orig_start = hole_start;
7075                         /*
7076                          * don't adjust block start at all,
7077                          * it is fixed at EXTENT_MAP_HOLE
7078                          */
7079                         em->block_start = hole_em->block_start;
7080                         em->block_len = hole_len;
7081                         if (test_bit(EXTENT_FLAG_PREALLOC, &hole_em->flags))
7082                                 set_bit(EXTENT_FLAG_PREALLOC, &em->flags);
7083                 } else {
7084                         em->start = range_start;
7085                         em->len = found;
7086                         em->orig_start = range_start;
7087                         em->block_start = EXTENT_MAP_DELALLOC;
7088                         em->block_len = found;
7089                 }
7090         } else {
7091                 return hole_em;
7092         }
7093 out:
7094
7095         free_extent_map(hole_em);
7096         if (err) {
7097                 free_extent_map(em);
7098                 return ERR_PTR(err);
7099         }
7100         return em;
7101 }
7102
7103 static struct extent_map *btrfs_create_dio_extent(struct inode *inode,
7104                                                   const u64 start,
7105                                                   const u64 len,
7106                                                   const u64 orig_start,
7107                                                   const u64 block_start,
7108                                                   const u64 block_len,
7109                                                   const u64 orig_block_len,
7110                                                   const u64 ram_bytes,
7111                                                   const int type)
7112 {
7113         struct extent_map *em = NULL;
7114         int ret;
7115
7116         if (type != BTRFS_ORDERED_NOCOW) {
7117                 em = create_io_em(inode, start, len, orig_start,
7118                                   block_start, block_len, orig_block_len,
7119                                   ram_bytes,
7120                                   BTRFS_COMPRESS_NONE, /* compress_type */
7121                                   type);
7122                 if (IS_ERR(em))
7123                         goto out;
7124         }
7125         ret = btrfs_add_ordered_extent_dio(inode, start, block_start,
7126                                            len, block_len, type);
7127         if (ret) {
7128                 if (em) {
7129                         free_extent_map(em);
7130                         btrfs_drop_extent_cache(BTRFS_I(inode), start,
7131                                                 start + len - 1, 0);
7132                 }
7133                 em = ERR_PTR(ret);
7134         }
7135  out:
7136
7137         return em;
7138 }
7139
7140 static struct extent_map *btrfs_new_extent_direct(struct inode *inode,
7141                                                   u64 start, u64 len)
7142 {
7143         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
7144         struct btrfs_root *root = BTRFS_I(inode)->root;
7145         struct extent_map *em;
7146         struct btrfs_key ins;
7147         u64 alloc_hint;
7148         int ret;
7149
7150         alloc_hint = get_extent_allocation_hint(inode, start, len);
7151         ret = btrfs_reserve_extent(root, len, len, fs_info->sectorsize,
7152                                    0, alloc_hint, &ins, 1, 1);
7153         if (ret)
7154                 return ERR_PTR(ret);
7155
7156         em = btrfs_create_dio_extent(inode, start, ins.offset, start,
7157                                      ins.objectid, ins.offset, ins.offset,
7158                                      ins.offset, BTRFS_ORDERED_REGULAR);
7159         btrfs_dec_block_group_reservations(fs_info, ins.objectid);
7160         if (IS_ERR(em))
7161                 btrfs_free_reserved_extent(fs_info, ins.objectid,
7162                                            ins.offset, 1);
7163
7164         return em;
7165 }
7166
7167 /*
7168  * returns 1 when the nocow is safe, < 1 on error, 0 if the
7169  * block must be cow'd
7170  */
7171 noinline int can_nocow_extent(struct inode *inode, u64 offset, u64 *len,
7172                               u64 *orig_start, u64 *orig_block_len,
7173                               u64 *ram_bytes)
7174 {
7175         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
7176         struct btrfs_path *path;
7177         int ret;
7178         struct extent_buffer *leaf;
7179         struct btrfs_root *root = BTRFS_I(inode)->root;
7180         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
7181         struct btrfs_file_extent_item *fi;
7182         struct btrfs_key key;
7183         u64 disk_bytenr;
7184         u64 backref_offset;
7185         u64 extent_end;
7186         u64 num_bytes;
7187         int slot;
7188         int found_type;
7189         bool nocow = (BTRFS_I(inode)->flags & BTRFS_INODE_NODATACOW);
7190
7191         path = btrfs_alloc_path();
7192         if (!path)
7193                 return -ENOMEM;
7194
7195         ret = btrfs_lookup_file_extent(NULL, root, path,
7196                         btrfs_ino(BTRFS_I(inode)), offset, 0);
7197         if (ret < 0)
7198                 goto out;
7199
7200         slot = path->slots[0];
7201         if (ret == 1) {
7202                 if (slot == 0) {
7203                         /* can't find the item, must cow */
7204                         ret = 0;
7205                         goto out;
7206                 }
7207                 slot--;
7208         }
7209         ret = 0;
7210         leaf = path->nodes[0];
7211         btrfs_item_key_to_cpu(leaf, &key, slot);
7212         if (key.objectid != btrfs_ino(BTRFS_I(inode)) ||
7213             key.type != BTRFS_EXTENT_DATA_KEY) {
7214                 /* not our file or wrong item type, must cow */
7215                 goto out;
7216         }
7217
7218         if (key.offset > offset) {
7219                 /* Wrong offset, must cow */
7220                 goto out;
7221         }
7222
7223         fi = btrfs_item_ptr(leaf, slot, struct btrfs_file_extent_item);
7224         found_type = btrfs_file_extent_type(leaf, fi);
7225         if (found_type != BTRFS_FILE_EXTENT_REG &&
7226             found_type != BTRFS_FILE_EXTENT_PREALLOC) {
7227                 /* not a regular extent, must cow */
7228                 goto out;
7229         }
7230
7231         if (!nocow && found_type == BTRFS_FILE_EXTENT_REG)
7232                 goto out;
7233
7234         extent_end = key.offset + btrfs_file_extent_num_bytes(leaf, fi);
7235         if (extent_end <= offset)
7236                 goto out;
7237
7238         disk_bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
7239         if (disk_bytenr == 0)
7240                 goto out;
7241
7242         if (btrfs_file_extent_compression(leaf, fi) ||
7243             btrfs_file_extent_encryption(leaf, fi) ||
7244             btrfs_file_extent_other_encoding(leaf, fi))
7245                 goto out;
7246
7247         /*
7248          * Do the same check as in btrfs_cross_ref_exist but without the
7249          * unnecessary search.
7250          */
7251         if (btrfs_file_extent_generation(leaf, fi) <=
7252             btrfs_root_last_snapshot(&root->root_item))
7253                 goto out;
7254
7255         backref_offset = btrfs_file_extent_offset(leaf, fi);
7256
7257         if (orig_start) {
7258                 *orig_start = key.offset - backref_offset;
7259                 *orig_block_len = btrfs_file_extent_disk_num_bytes(leaf, fi);
7260                 *ram_bytes = btrfs_file_extent_ram_bytes(leaf, fi);
7261         }
7262
7263         if (btrfs_extent_readonly(fs_info, disk_bytenr))
7264                 goto out;
7265
7266         num_bytes = min(offset + *len, extent_end) - offset;
7267         if (!nocow && found_type == BTRFS_FILE_EXTENT_PREALLOC) {
7268                 u64 range_end;
7269
7270                 range_end = round_up(offset + num_bytes,
7271                                      root->fs_info->sectorsize) - 1;
7272                 ret = test_range_bit(io_tree, offset, range_end,
7273                                      EXTENT_DELALLOC, 0, NULL);
7274                 if (ret) {
7275                         ret = -EAGAIN;
7276                         goto out;
7277                 }
7278         }
7279
7280         btrfs_release_path(path);
7281
7282         /*
7283          * look for other files referencing this extent, if we
7284          * find any we must cow
7285          */
7286
7287         ret = btrfs_cross_ref_exist(root, btrfs_ino(BTRFS_I(inode)),
7288                                     key.offset - backref_offset, disk_bytenr);
7289         if (ret) {
7290                 ret = 0;
7291                 goto out;
7292         }
7293
7294         /*
7295          * adjust disk_bytenr and num_bytes to cover just the bytes
7296          * in this extent we are about to write.  If there
7297          * are any csums in that range we have to cow in order
7298          * to keep the csums correct
7299          */
7300         disk_bytenr += backref_offset;
7301         disk_bytenr += offset - key.offset;
7302         if (csum_exist_in_range(fs_info, disk_bytenr, num_bytes))
7303                 goto out;
7304         /*
7305          * all of the above have passed, it is safe to overwrite this extent
7306          * without cow
7307          */
7308         *len = num_bytes;
7309         ret = 1;
7310 out:
7311         btrfs_free_path(path);
7312         return ret;
7313 }
7314
7315 static int lock_extent_direct(struct inode *inode, u64 lockstart, u64 lockend,
7316                               struct extent_state **cached_state, int writing)
7317 {
7318         struct btrfs_ordered_extent *ordered;
7319         int ret = 0;
7320
7321         while (1) {
7322                 lock_extent_bits(&BTRFS_I(inode)->io_tree, lockstart, lockend,
7323                                  cached_state);
7324                 /*
7325                  * We're concerned with the entire range that we're going to be
7326                  * doing DIO to, so we need to make sure there's no ordered
7327                  * extents in this range.
7328                  */
7329                 ordered = btrfs_lookup_ordered_range(BTRFS_I(inode), lockstart,
7330                                                      lockend - lockstart + 1);
7331
7332                 /*
7333                  * We need to make sure there are no buffered pages in this
7334                  * range either, we could have raced between the invalidate in
7335                  * generic_file_direct_write and locking the extent.  The
7336                  * invalidate needs to happen so that reads after a write do not
7337                  * get stale data.
7338                  */
7339                 if (!ordered &&
7340                     (!writing || !filemap_range_has_page(inode->i_mapping,
7341                                                          lockstart, lockend)))
7342                         break;
7343
7344                 unlock_extent_cached(&BTRFS_I(inode)->io_tree, lockstart, lockend,
7345                                      cached_state);
7346
7347                 if (ordered) {
7348                         /*
7349                          * If we are doing a DIO read and the ordered extent we
7350                          * found is for a buffered write, we can not wait for it
7351                          * to complete and retry, because if we do so we can
7352                          * deadlock with concurrent buffered writes on page
7353                          * locks. This happens only if our DIO read covers more
7354                          * than one extent map, if at this point has already
7355                          * created an ordered extent for a previous extent map
7356                          * and locked its range in the inode's io tree, and a
7357                          * concurrent write against that previous extent map's
7358                          * range and this range started (we unlock the ranges
7359                          * in the io tree only when the bios complete and
7360                          * buffered writes always lock pages before attempting
7361                          * to lock range in the io tree).
7362                          */
7363                         if (writing ||
7364                             test_bit(BTRFS_ORDERED_DIRECT, &ordered->flags))
7365                                 btrfs_start_ordered_extent(inode, ordered, 1);
7366                         else
7367                                 ret = -ENOTBLK;
7368                         btrfs_put_ordered_extent(ordered);
7369                 } else {
7370                         /*
7371                          * We could trigger writeback for this range (and wait
7372                          * for it to complete) and then invalidate the pages for
7373                          * this range (through invalidate_inode_pages2_range()),
7374                          * but that can lead us to a deadlock with a concurrent
7375                          * call to readpages() (a buffered read or a defrag call
7376                          * triggered a readahead) on a page lock due to an
7377                          * ordered dio extent we created before but did not have
7378                          * yet a corresponding bio submitted (whence it can not
7379                          * complete), which makes readpages() wait for that
7380                          * ordered extent to complete while holding a lock on
7381                          * that page.
7382                          */
7383                         ret = -ENOTBLK;
7384                 }
7385
7386                 if (ret)
7387                         break;
7388
7389                 cond_resched();
7390         }
7391
7392         return ret;
7393 }
7394
7395 /* The callers of this must take lock_extent() */
7396 static struct extent_map *create_io_em(struct inode *inode, u64 start, u64 len,
7397                                        u64 orig_start, u64 block_start,
7398                                        u64 block_len, u64 orig_block_len,
7399                                        u64 ram_bytes, int compress_type,
7400                                        int type)
7401 {
7402         struct extent_map_tree *em_tree;
7403         struct extent_map *em;
7404         struct btrfs_root *root = BTRFS_I(inode)->root;
7405         int ret;
7406
7407         ASSERT(type == BTRFS_ORDERED_PREALLOC ||
7408                type == BTRFS_ORDERED_COMPRESSED ||
7409                type == BTRFS_ORDERED_NOCOW ||
7410                type == BTRFS_ORDERED_REGULAR);
7411
7412         em_tree = &BTRFS_I(inode)->extent_tree;
7413         em = alloc_extent_map();
7414         if (!em)
7415                 return ERR_PTR(-ENOMEM);
7416
7417         em->start = start;
7418         em->orig_start = orig_start;
7419         em->len = len;
7420         em->block_len = block_len;
7421         em->block_start = block_start;
7422         em->bdev = root->fs_info->fs_devices->latest_bdev;
7423         em->orig_block_len = orig_block_len;
7424         em->ram_bytes = ram_bytes;
7425         em->generation = -1;
7426         set_bit(EXTENT_FLAG_PINNED, &em->flags);
7427         if (type == BTRFS_ORDERED_PREALLOC) {
7428                 set_bit(EXTENT_FLAG_FILLING, &em->flags);
7429         } else if (type == BTRFS_ORDERED_COMPRESSED) {
7430                 set_bit(EXTENT_FLAG_COMPRESSED, &em->flags);
7431                 em->compress_type = compress_type;
7432         }
7433
7434         do {
7435                 btrfs_drop_extent_cache(BTRFS_I(inode), em->start,
7436                                 em->start + em->len - 1, 0);
7437                 write_lock(&em_tree->lock);
7438                 ret = add_extent_mapping(em_tree, em, 1);
7439                 write_unlock(&em_tree->lock);
7440                 /*
7441                  * The caller has taken lock_extent(), who could race with us
7442                  * to add em?
7443                  */
7444         } while (ret == -EEXIST);
7445
7446         if (ret) {
7447                 free_extent_map(em);
7448                 return ERR_PTR(ret);
7449         }
7450
7451         /* em got 2 refs now, callers needs to do free_extent_map once. */
7452         return em;
7453 }
7454
7455
7456 static int btrfs_get_blocks_direct_read(struct extent_map *em,
7457                                         struct buffer_head *bh_result,
7458                                         struct inode *inode,
7459                                         u64 start, u64 len)
7460 {
7461         if (em->block_start == EXTENT_MAP_HOLE ||
7462                         test_bit(EXTENT_FLAG_PREALLOC, &em->flags))
7463                 return -ENOENT;
7464
7465         len = min(len, em->len - (start - em->start));
7466
7467         bh_result->b_blocknr = (em->block_start + (start - em->start)) >>
7468                 inode->i_blkbits;
7469         bh_result->b_size = len;
7470         bh_result->b_bdev = em->bdev;
7471         set_buffer_mapped(bh_result);
7472
7473         return 0;
7474 }
7475
7476 static int btrfs_get_blocks_direct_write(struct extent_map **map,
7477                                          struct buffer_head *bh_result,
7478                                          struct inode *inode,
7479                                          struct btrfs_dio_data *dio_data,
7480                                          u64 start, u64 len)
7481 {
7482         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
7483         struct extent_map *em = *map;
7484         int ret = 0;
7485
7486         /*
7487          * We don't allocate a new extent in the following cases
7488          *
7489          * 1) The inode is marked as NODATACOW. In this case we'll just use the
7490          * existing extent.
7491          * 2) The extent is marked as PREALLOC. We're good to go here and can
7492          * just use the extent.
7493          *
7494          */
7495         if (test_bit(EXTENT_FLAG_PREALLOC, &em->flags) ||
7496             ((BTRFS_I(inode)->flags & BTRFS_INODE_NODATACOW) &&
7497              em->block_start != EXTENT_MAP_HOLE)) {
7498                 int type;
7499                 u64 block_start, orig_start, orig_block_len, ram_bytes;
7500
7501                 if (test_bit(EXTENT_FLAG_PREALLOC, &em->flags))
7502                         type = BTRFS_ORDERED_PREALLOC;
7503                 else
7504                         type = BTRFS_ORDERED_NOCOW;
7505                 len = min(len, em->len - (start - em->start));
7506                 block_start = em->block_start + (start - em->start);
7507
7508                 if (can_nocow_extent(inode, start, &len, &orig_start,
7509                                      &orig_block_len, &ram_bytes) == 1 &&
7510                     btrfs_inc_nocow_writers(fs_info, block_start)) {
7511                         struct extent_map *em2;
7512
7513                         em2 = btrfs_create_dio_extent(inode, start, len,
7514                                                       orig_start, block_start,
7515                                                       len, orig_block_len,
7516                                                       ram_bytes, type);
7517                         btrfs_dec_nocow_writers(fs_info, block_start);
7518                         if (type == BTRFS_ORDERED_PREALLOC) {
7519                                 free_extent_map(em);
7520                                 *map = em = em2;
7521                         }
7522
7523                         if (em2 && IS_ERR(em2)) {
7524                                 ret = PTR_ERR(em2);
7525                                 goto out;
7526                         }
7527                         /*
7528                          * For inode marked NODATACOW or extent marked PREALLOC,
7529                          * use the existing or preallocated extent, so does not
7530                          * need to adjust btrfs_space_info's bytes_may_use.
7531                          */
7532                         btrfs_free_reserved_data_space_noquota(inode, start,
7533                                                                len);
7534                         goto skip_cow;
7535                 }
7536         }
7537
7538         /* this will cow the extent */
7539         len = bh_result->b_size;
7540         free_extent_map(em);
7541         *map = em = btrfs_new_extent_direct(inode, start, len);
7542         if (IS_ERR(em)) {
7543                 ret = PTR_ERR(em);
7544                 goto out;
7545         }
7546
7547         len = min(len, em->len - (start - em->start));
7548
7549 skip_cow:
7550         bh_result->b_blocknr = (em->block_start + (start - em->start)) >>
7551                 inode->i_blkbits;
7552         bh_result->b_size = len;
7553         bh_result->b_bdev = em->bdev;
7554         set_buffer_mapped(bh_result);
7555
7556         if (!test_bit(EXTENT_FLAG_PREALLOC, &em->flags))
7557                 set_buffer_new(bh_result);
7558
7559         /*
7560          * Need to update the i_size under the extent lock so buffered
7561          * readers will get the updated i_size when we unlock.
7562          */
7563         if (!dio_data->overwrite && start + len > i_size_read(inode))
7564                 i_size_write(inode, start + len);
7565
7566         WARN_ON(dio_data->reserve < len);
7567         dio_data->reserve -= len;
7568         dio_data->unsubmitted_oe_range_end = start + len;
7569         current->journal_info = dio_data;
7570 out:
7571         return ret;
7572 }
7573
7574 static int btrfs_get_blocks_direct(struct inode *inode, sector_t iblock,
7575                                    struct buffer_head *bh_result, int create)
7576 {
7577         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
7578         struct extent_map *em;
7579         struct extent_state *cached_state = NULL;
7580         struct btrfs_dio_data *dio_data = NULL;
7581         u64 start = iblock << inode->i_blkbits;
7582         u64 lockstart, lockend;
7583         u64 len = bh_result->b_size;
7584         int unlock_bits = EXTENT_LOCKED;
7585         int ret = 0;
7586
7587         if (create)
7588                 unlock_bits |= EXTENT_DIRTY;
7589         else
7590                 len = min_t(u64, len, fs_info->sectorsize);
7591
7592         lockstart = start;
7593         lockend = start + len - 1;
7594
7595         if (current->journal_info) {
7596                 /*
7597                  * Need to pull our outstanding extents and set journal_info to NULL so
7598                  * that anything that needs to check if there's a transaction doesn't get
7599                  * confused.
7600                  */
7601                 dio_data = current->journal_info;
7602                 current->journal_info = NULL;
7603         }
7604
7605         /*
7606          * If this errors out it's because we couldn't invalidate pagecache for
7607          * this range and we need to fallback to buffered.
7608          */
7609         if (lock_extent_direct(inode, lockstart, lockend, &cached_state,
7610                                create)) {
7611                 ret = -ENOTBLK;
7612                 goto err;
7613         }
7614
7615         em = btrfs_get_extent(BTRFS_I(inode), NULL, 0, start, len, 0);
7616         if (IS_ERR(em)) {
7617                 ret = PTR_ERR(em);
7618                 goto unlock_err;
7619         }
7620
7621         /*
7622          * Ok for INLINE and COMPRESSED extents we need to fallback on buffered
7623          * io.  INLINE is special, and we could probably kludge it in here, but
7624          * it's still buffered so for safety lets just fall back to the generic
7625          * buffered path.
7626          *
7627          * For COMPRESSED we _have_ to read the entire extent in so we can
7628          * decompress it, so there will be buffering required no matter what we
7629          * do, so go ahead and fallback to buffered.
7630          *
7631          * We return -ENOTBLK because that's what makes DIO go ahead and go back
7632          * to buffered IO.  Don't blame me, this is the price we pay for using
7633          * the generic code.
7634          */
7635         if (test_bit(EXTENT_FLAG_COMPRESSED, &em->flags) ||
7636             em->block_start == EXTENT_MAP_INLINE) {
7637                 free_extent_map(em);
7638                 ret = -ENOTBLK;
7639                 goto unlock_err;
7640         }
7641
7642         if (create) {
7643                 ret = btrfs_get_blocks_direct_write(&em, bh_result, inode,
7644                                                     dio_data, start, len);
7645                 if (ret < 0)
7646                         goto unlock_err;
7647
7648                 /* clear and unlock the entire range */
7649                 clear_extent_bit(&BTRFS_I(inode)->io_tree, lockstart, lockend,
7650                                  unlock_bits, 1, 0, &cached_state);
7651         } else {
7652                 ret = btrfs_get_blocks_direct_read(em, bh_result, inode,
7653                                                    start, len);
7654                 /* Can be negative only if we read from a hole */
7655                 if (ret < 0) {
7656                         ret = 0;
7657                         free_extent_map(em);
7658                         goto unlock_err;
7659                 }
7660                 /*
7661                  * We need to unlock only the end area that we aren't using.
7662                  * The rest is going to be unlocked by the endio routine.
7663                  */
7664                 lockstart = start + bh_result->b_size;
7665                 if (lockstart < lockend) {
7666                         clear_extent_bit(&BTRFS_I(inode)->io_tree, lockstart,
7667                                          lockend, unlock_bits, 1, 0,
7668                                          &cached_state);
7669                 } else {
7670                         free_extent_state(cached_state);
7671                 }
7672         }
7673
7674         free_extent_map(em);
7675
7676         return 0;
7677
7678 unlock_err:
7679         clear_extent_bit(&BTRFS_I(inode)->io_tree, lockstart, lockend,
7680                          unlock_bits, 1, 0, &cached_state);
7681 err:
7682         if (dio_data)
7683                 current->journal_info = dio_data;
7684         return ret;
7685 }
7686
7687 static inline blk_status_t submit_dio_repair_bio(struct inode *inode,
7688                                                  struct bio *bio,
7689                                                  int mirror_num)
7690 {
7691         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
7692         blk_status_t ret;
7693
7694         BUG_ON(bio_op(bio) == REQ_OP_WRITE);
7695
7696         ret = btrfs_bio_wq_end_io(fs_info, bio, BTRFS_WQ_ENDIO_DIO_REPAIR);
7697         if (ret)
7698                 return ret;
7699
7700         ret = btrfs_map_bio(fs_info, bio, mirror_num, 0);
7701
7702         return ret;
7703 }
7704
7705 static int btrfs_check_dio_repairable(struct inode *inode,
7706                                       struct bio *failed_bio,
7707                                       struct io_failure_record *failrec,
7708                                       int failed_mirror)
7709 {
7710         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
7711         int num_copies;
7712
7713         num_copies = btrfs_num_copies(fs_info, failrec->logical, failrec->len);
7714         if (num_copies == 1) {
7715                 /*
7716                  * we only have a single copy of the data, so don't bother with
7717                  * all the retry and error correction code that follows. no
7718                  * matter what the error is, it is very likely to persist.
7719                  */
7720                 btrfs_debug(fs_info,
7721                         "Check DIO Repairable: cannot repair, num_copies=%d, next_mirror %d, failed_mirror %d",
7722                         num_copies, failrec->this_mirror, failed_mirror);
7723                 return 0;
7724         }
7725
7726         failrec->failed_mirror = failed_mirror;
7727         failrec->this_mirror++;
7728         if (failrec->this_mirror == failed_mirror)
7729                 failrec->this_mirror++;
7730
7731         if (failrec->this_mirror > num_copies) {
7732                 btrfs_debug(fs_info,
7733                         "Check DIO Repairable: (fail) num_copies=%d, next_mirror %d, failed_mirror %d",
7734                         num_copies, failrec->this_mirror, failed_mirror);
7735                 return 0;
7736         }
7737
7738         return 1;
7739 }
7740
7741 static blk_status_t dio_read_error(struct inode *inode, struct bio *failed_bio,
7742                                    struct page *page, unsigned int pgoff,
7743                                    u64 start, u64 end, int failed_mirror,
7744                                    bio_end_io_t *repair_endio, void *repair_arg)
7745 {
7746         struct io_failure_record *failrec;
7747         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
7748         struct extent_io_tree *failure_tree = &BTRFS_I(inode)->io_failure_tree;
7749         struct bio *bio;
7750         int isector;
7751         unsigned int read_mode = 0;
7752         int segs;
7753         int ret;
7754         blk_status_t status;
7755         struct bio_vec bvec;
7756
7757         BUG_ON(bio_op(failed_bio) == REQ_OP_WRITE);
7758
7759         ret = btrfs_get_io_failure_record(inode, start, end, &failrec);
7760         if (ret)
7761                 return errno_to_blk_status(ret);
7762
7763         ret = btrfs_check_dio_repairable(inode, failed_bio, failrec,
7764                                          failed_mirror);
7765         if (!ret) {
7766                 free_io_failure(failure_tree, io_tree, failrec);
7767                 return BLK_STS_IOERR;
7768         }
7769
7770         segs = bio_segments(failed_bio);
7771         bio_get_first_bvec(failed_bio, &bvec);
7772         if (segs > 1 ||
7773             (bvec.bv_len > btrfs_inode_sectorsize(inode)))
7774                 read_mode |= REQ_FAILFAST_DEV;
7775
7776         isector = start - btrfs_io_bio(failed_bio)->logical;
7777         isector >>= inode->i_sb->s_blocksize_bits;
7778         bio = btrfs_create_repair_bio(inode, failed_bio, failrec, page,
7779                                 pgoff, isector, repair_endio, repair_arg);
7780         bio->bi_opf = REQ_OP_READ | read_mode;
7781
7782         btrfs_debug(BTRFS_I(inode)->root->fs_info,
7783                     "repair DIO read error: submitting new dio read[%#x] to this_mirror=%d, in_validation=%d",
7784                     read_mode, failrec->this_mirror, failrec->in_validation);
7785
7786         status = submit_dio_repair_bio(inode, bio, failrec->this_mirror);
7787         if (status) {
7788                 free_io_failure(failure_tree, io_tree, failrec);
7789                 bio_put(bio);
7790         }
7791
7792         return status;
7793 }
7794
7795 struct btrfs_retry_complete {
7796         struct completion done;
7797         struct inode *inode;
7798         u64 start;
7799         int uptodate;
7800 };
7801
7802 static void btrfs_retry_endio_nocsum(struct bio *bio)
7803 {
7804         struct btrfs_retry_complete *done = bio->bi_private;
7805         struct inode *inode = done->inode;
7806         struct bio_vec *bvec;
7807         struct extent_io_tree *io_tree, *failure_tree;
7808         int i;
7809
7810         if (bio->bi_status)
7811                 goto end;
7812
7813         ASSERT(bio->bi_vcnt == 1);
7814         io_tree = &BTRFS_I(inode)->io_tree;
7815         failure_tree = &BTRFS_I(inode)->io_failure_tree;
7816         ASSERT(bio_first_bvec_all(bio)->bv_len == btrfs_inode_sectorsize(inode));
7817
7818         done->uptodate = 1;
7819         ASSERT(!bio_flagged(bio, BIO_CLONED));
7820         bio_for_each_segment_all(bvec, bio, i)
7821                 clean_io_failure(BTRFS_I(inode)->root->fs_info, failure_tree,
7822                                  io_tree, done->start, bvec->bv_page,
7823                                  btrfs_ino(BTRFS_I(inode)), 0);
7824 end:
7825         complete(&done->done);
7826         bio_put(bio);
7827 }
7828
7829 static blk_status_t __btrfs_correct_data_nocsum(struct inode *inode,
7830                                                 struct btrfs_io_bio *io_bio)
7831 {
7832         struct btrfs_fs_info *fs_info;
7833         struct bio_vec bvec;
7834         struct bvec_iter iter;
7835         struct btrfs_retry_complete done;
7836         u64 start;
7837         unsigned int pgoff;
7838         u32 sectorsize;
7839         int nr_sectors;
7840         blk_status_t ret;
7841         blk_status_t err = BLK_STS_OK;
7842
7843         fs_info = BTRFS_I(inode)->root->fs_info;
7844         sectorsize = fs_info->sectorsize;
7845
7846         start = io_bio->logical;
7847         done.inode = inode;
7848         io_bio->bio.bi_iter = io_bio->iter;
7849
7850         bio_for_each_segment(bvec, &io_bio->bio, iter) {
7851                 nr_sectors = BTRFS_BYTES_TO_BLKS(fs_info, bvec.bv_len);
7852                 pgoff = bvec.bv_offset;
7853
7854 next_block_or_try_again:
7855                 done.uptodate = 0;
7856                 done.start = start;
7857                 init_completion(&done.done);
7858
7859                 ret = dio_read_error(inode, &io_bio->bio, bvec.bv_page,
7860                                 pgoff, start, start + sectorsize - 1,
7861                                 io_bio->mirror_num,
7862                                 btrfs_retry_endio_nocsum, &done);
7863                 if (ret) {
7864                         err = ret;
7865                         goto next;
7866                 }
7867
7868                 wait_for_completion_io(&done.done);
7869
7870                 if (!done.uptodate) {
7871                         /* We might have another mirror, so try again */
7872                         goto next_block_or_try_again;
7873                 }
7874
7875 next:
7876                 start += sectorsize;
7877
7878                 nr_sectors--;
7879                 if (nr_sectors) {
7880                         pgoff += sectorsize;
7881                         ASSERT(pgoff < PAGE_SIZE);
7882                         goto next_block_or_try_again;
7883                 }
7884         }
7885
7886         return err;
7887 }
7888
7889 static void btrfs_retry_endio(struct bio *bio)
7890 {
7891         struct btrfs_retry_complete *done = bio->bi_private;
7892         struct btrfs_io_bio *io_bio = btrfs_io_bio(bio);
7893         struct extent_io_tree *io_tree, *failure_tree;
7894         struct inode *inode = done->inode;
7895         struct bio_vec *bvec;
7896         int uptodate;
7897         int ret;
7898         int i;
7899
7900         if (bio->bi_status)
7901                 goto end;
7902
7903         uptodate = 1;
7904
7905         ASSERT(bio->bi_vcnt == 1);
7906         ASSERT(bio_first_bvec_all(bio)->bv_len == btrfs_inode_sectorsize(done->inode));
7907
7908         io_tree = &BTRFS_I(inode)->io_tree;
7909         failure_tree = &BTRFS_I(inode)->io_failure_tree;
7910
7911         ASSERT(!bio_flagged(bio, BIO_CLONED));
7912         bio_for_each_segment_all(bvec, bio, i) {
7913                 ret = __readpage_endio_check(inode, io_bio, i, bvec->bv_page,
7914                                              bvec->bv_offset, done->start,
7915                                              bvec->bv_len);
7916                 if (!ret)
7917                         clean_io_failure(BTRFS_I(inode)->root->fs_info,
7918                                          failure_tree, io_tree, done->start,
7919                                          bvec->bv_page,
7920                                          btrfs_ino(BTRFS_I(inode)),
7921                                          bvec->bv_offset);
7922                 else
7923                         uptodate = 0;
7924         }
7925
7926         done->uptodate = uptodate;
7927 end:
7928         complete(&done->done);
7929         bio_put(bio);
7930 }
7931
7932 static blk_status_t __btrfs_subio_endio_read(struct inode *inode,
7933                 struct btrfs_io_bio *io_bio, blk_status_t err)
7934 {
7935         struct btrfs_fs_info *fs_info;
7936         struct bio_vec bvec;
7937         struct bvec_iter iter;
7938         struct btrfs_retry_complete done;
7939         u64 start;
7940         u64 offset = 0;
7941         u32 sectorsize;
7942         int nr_sectors;
7943         unsigned int pgoff;
7944         int csum_pos;
7945         bool uptodate = (err == 0);
7946         int ret;
7947         blk_status_t status;
7948
7949         fs_info = BTRFS_I(inode)->root->fs_info;
7950         sectorsize = fs_info->sectorsize;
7951
7952         err = BLK_STS_OK;
7953         start = io_bio->logical;
7954         done.inode = inode;
7955         io_bio->bio.bi_iter = io_bio->iter;
7956
7957         bio_for_each_segment(bvec, &io_bio->bio, iter) {
7958                 nr_sectors = BTRFS_BYTES_TO_BLKS(fs_info, bvec.bv_len);
7959
7960                 pgoff = bvec.bv_offset;
7961 next_block:
7962                 if (uptodate) {
7963                         csum_pos = BTRFS_BYTES_TO_BLKS(fs_info, offset);
7964                         ret = __readpage_endio_check(inode, io_bio, csum_pos,
7965                                         bvec.bv_page, pgoff, start, sectorsize);
7966                         if (likely(!ret))
7967                                 goto next;
7968                 }
7969 try_again:
7970                 done.uptodate = 0;
7971                 done.start = start;
7972                 init_completion(&done.done);
7973
7974                 status = dio_read_error(inode, &io_bio->bio, bvec.bv_page,
7975                                         pgoff, start, start + sectorsize - 1,
7976                                         io_bio->mirror_num, btrfs_retry_endio,
7977                                         &done);
7978                 if (status) {
7979                         err = status;
7980                         goto next;
7981                 }
7982
7983                 wait_for_completion_io(&done.done);
7984
7985                 if (!done.uptodate) {
7986                         /* We might have another mirror, so try again */
7987                         goto try_again;
7988                 }
7989 next:
7990                 offset += sectorsize;
7991                 start += sectorsize;
7992
7993                 ASSERT(nr_sectors);
7994
7995                 nr_sectors--;
7996                 if (nr_sectors) {
7997                         pgoff += sectorsize;
7998                         ASSERT(pgoff < PAGE_SIZE);
7999                         goto next_block;
8000                 }
8001         }
8002
8003         return err;
8004 }
8005
8006 static blk_status_t btrfs_subio_endio_read(struct inode *inode,
8007                 struct btrfs_io_bio *io_bio, blk_status_t err)
8008 {
8009         bool skip_csum = BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM;
8010
8011         if (skip_csum) {
8012                 if (unlikely(err))
8013                         return __btrfs_correct_data_nocsum(inode, io_bio);
8014                 else
8015                         return BLK_STS_OK;
8016         } else {
8017                 return __btrfs_subio_endio_read(inode, io_bio, err);
8018         }
8019 }
8020
8021 static void btrfs_endio_direct_read(struct bio *bio)
8022 {
8023         struct btrfs_dio_private *dip = bio->bi_private;
8024         struct inode *inode = dip->inode;
8025         struct bio *dio_bio;
8026         struct btrfs_io_bio *io_bio = btrfs_io_bio(bio);
8027         blk_status_t err = bio->bi_status;
8028
8029         if (dip->flags & BTRFS_DIO_ORIG_BIO_SUBMITTED)
8030                 err = btrfs_subio_endio_read(inode, io_bio, err);
8031
8032         unlock_extent(&BTRFS_I(inode)->io_tree, dip->logical_offset,
8033                       dip->logical_offset + dip->bytes - 1);
8034         dio_bio = dip->dio_bio;
8035
8036         kfree(dip);
8037
8038         dio_bio->bi_status = err;
8039         dio_end_io(dio_bio);
8040
8041         if (io_bio->end_io)
8042                 io_bio->end_io(io_bio, blk_status_to_errno(err));
8043         bio_put(bio);
8044 }
8045
8046 static void __endio_write_update_ordered(struct inode *inode,
8047                                          const u64 offset, const u64 bytes,
8048                                          const bool uptodate)
8049 {
8050         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
8051         struct btrfs_ordered_extent *ordered = NULL;
8052         struct btrfs_workqueue *wq;
8053         btrfs_work_func_t func;
8054         u64 ordered_offset = offset;
8055         u64 ordered_bytes = bytes;
8056         u64 last_offset;
8057
8058         if (btrfs_is_free_space_inode(BTRFS_I(inode))) {
8059                 wq = fs_info->endio_freespace_worker;
8060                 func = btrfs_freespace_write_helper;
8061         } else {
8062                 wq = fs_info->endio_write_workers;
8063                 func = btrfs_endio_write_helper;
8064         }
8065
8066         while (ordered_offset < offset + bytes) {
8067                 last_offset = ordered_offset;
8068                 if (btrfs_dec_test_first_ordered_pending(inode, &ordered,
8069                                                            &ordered_offset,
8070                                                            ordered_bytes,
8071                                                            uptodate)) {
8072                         btrfs_init_work(&ordered->work, func,
8073                                         finish_ordered_fn,
8074                                         NULL, NULL);
8075                         btrfs_queue_work(wq, &ordered->work);
8076                 }
8077                 /*
8078                  * If btrfs_dec_test_ordered_pending does not find any ordered
8079                  * extent in the range, we can exit.
8080                  */
8081                 if (ordered_offset == last_offset)
8082                         return;
8083                 /*
8084                  * Our bio might span multiple ordered extents. In this case
8085                  * we keep goin until we have accounted the whole dio.
8086                  */
8087                 if (ordered_offset < offset + bytes) {
8088                         ordered_bytes = offset + bytes - ordered_offset;
8089                         ordered = NULL;
8090                 }
8091         }
8092 }
8093
8094 static void btrfs_endio_direct_write(struct bio *bio)
8095 {
8096         struct btrfs_dio_private *dip = bio->bi_private;
8097         struct bio *dio_bio = dip->dio_bio;
8098
8099         __endio_write_update_ordered(dip->inode, dip->logical_offset,
8100                                      dip->bytes, !bio->bi_status);
8101
8102         kfree(dip);
8103
8104         dio_bio->bi_status = bio->bi_status;
8105         dio_end_io(dio_bio);
8106         bio_put(bio);
8107 }
8108
8109 static blk_status_t btrfs_submit_bio_start_direct_io(void *private_data,
8110                                     struct bio *bio, u64 offset)
8111 {
8112         struct inode *inode = private_data;
8113         blk_status_t ret;
8114         ret = btrfs_csum_one_bio(inode, bio, offset, 1);
8115         BUG_ON(ret); /* -ENOMEM */
8116         return 0;
8117 }
8118
8119 static void btrfs_end_dio_bio(struct bio *bio)
8120 {
8121         struct btrfs_dio_private *dip = bio->bi_private;
8122         blk_status_t err = bio->bi_status;
8123
8124         if (err)
8125                 btrfs_warn(BTRFS_I(dip->inode)->root->fs_info,
8126                            "direct IO failed ino %llu rw %d,%u sector %#Lx len %u err no %d",
8127                            btrfs_ino(BTRFS_I(dip->inode)), bio_op(bio),
8128                            bio->bi_opf,
8129                            (unsigned long long)bio->bi_iter.bi_sector,
8130                            bio->bi_iter.bi_size, err);
8131
8132         if (dip->subio_endio)
8133                 err = dip->subio_endio(dip->inode, btrfs_io_bio(bio), err);
8134
8135         if (err) {
8136                 /*
8137                  * We want to perceive the errors flag being set before
8138                  * decrementing the reference count. We don't need a barrier
8139                  * since atomic operations with a return value are fully
8140                  * ordered as per atomic_t.txt
8141                  */
8142                 dip->errors = 1;
8143         }
8144
8145         /* if there are more bios still pending for this dio, just exit */
8146         if (!atomic_dec_and_test(&dip->pending_bios))
8147                 goto out;
8148
8149         if (dip->errors) {
8150                 bio_io_error(dip->orig_bio);
8151         } else {
8152                 dip->dio_bio->bi_status = BLK_STS_OK;
8153                 bio_endio(dip->orig_bio);
8154         }
8155 out:
8156         bio_put(bio);
8157 }
8158
8159 static inline blk_status_t btrfs_lookup_and_bind_dio_csum(struct inode *inode,
8160                                                  struct btrfs_dio_private *dip,
8161                                                  struct bio *bio,
8162                                                  u64 file_offset)
8163 {
8164         struct btrfs_io_bio *io_bio = btrfs_io_bio(bio);
8165         struct btrfs_io_bio *orig_io_bio = btrfs_io_bio(dip->orig_bio);
8166         blk_status_t ret;
8167
8168         /*
8169          * We load all the csum data we need when we submit
8170          * the first bio to reduce the csum tree search and
8171          * contention.
8172          */
8173         if (dip->logical_offset == file_offset) {
8174                 ret = btrfs_lookup_bio_sums_dio(inode, dip->orig_bio,
8175                                                 file_offset);
8176                 if (ret)
8177                         return ret;
8178         }
8179
8180         if (bio == dip->orig_bio)
8181                 return 0;
8182
8183         file_offset -= dip->logical_offset;
8184         file_offset >>= inode->i_sb->s_blocksize_bits;
8185         io_bio->csum = (u8 *)(((u32 *)orig_io_bio->csum) + file_offset);
8186
8187         return 0;
8188 }
8189
8190 static inline blk_status_t btrfs_submit_dio_bio(struct bio *bio,
8191                 struct inode *inode, u64 file_offset, int async_submit)
8192 {
8193         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
8194         struct btrfs_dio_private *dip = bio->bi_private;
8195         bool write = bio_op(bio) == REQ_OP_WRITE;
8196         blk_status_t ret;
8197
8198         /* Check btrfs_submit_bio_hook() for rules about async submit. */
8199         if (async_submit)
8200                 async_submit = !atomic_read(&BTRFS_I(inode)->sync_writers);
8201
8202         if (!write) {
8203                 ret = btrfs_bio_wq_end_io(fs_info, bio, BTRFS_WQ_ENDIO_DATA);
8204                 if (ret)
8205                         goto err;
8206         }
8207
8208         if (BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM)
8209                 goto map;
8210
8211         if (write && async_submit) {
8212                 ret = btrfs_wq_submit_bio(fs_info, bio, 0, 0,
8213                                           file_offset, inode,
8214                                           btrfs_submit_bio_start_direct_io);
8215                 goto err;
8216         } else if (write) {
8217                 /*
8218                  * If we aren't doing async submit, calculate the csum of the
8219                  * bio now.
8220                  */
8221                 ret = btrfs_csum_one_bio(inode, bio, file_offset, 1);
8222                 if (ret)
8223                         goto err;
8224         } else {
8225                 ret = btrfs_lookup_and_bind_dio_csum(inode, dip, bio,
8226                                                      file_offset);
8227                 if (ret)
8228                         goto err;
8229         }
8230 map:
8231         ret = btrfs_map_bio(fs_info, bio, 0, 0);
8232 err:
8233         return ret;
8234 }
8235
8236 static int btrfs_submit_direct_hook(struct btrfs_dio_private *dip)
8237 {
8238         struct inode *inode = dip->inode;
8239         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
8240         struct bio *bio;
8241         struct bio *orig_bio = dip->orig_bio;
8242         u64 start_sector = orig_bio->bi_iter.bi_sector;
8243         u64 file_offset = dip->logical_offset;
8244         u64 map_length;
8245         int async_submit = 0;
8246         u64 submit_len;
8247         int clone_offset = 0;
8248         int clone_len;
8249         int ret;
8250         blk_status_t status;
8251
8252         map_length = orig_bio->bi_iter.bi_size;
8253         submit_len = map_length;
8254         ret = btrfs_map_block(fs_info, btrfs_op(orig_bio), start_sector << 9,
8255                               &map_length, NULL, 0);
8256         if (ret)
8257                 return -EIO;
8258
8259         if (map_length >= submit_len) {
8260                 bio = orig_bio;
8261                 dip->flags |= BTRFS_DIO_ORIG_BIO_SUBMITTED;
8262                 goto submit;
8263         }
8264
8265         /* async crcs make it difficult to collect full stripe writes. */
8266         if (btrfs_data_alloc_profile(fs_info) & BTRFS_BLOCK_GROUP_RAID56_MASK)
8267                 async_submit = 0;
8268         else
8269                 async_submit = 1;
8270
8271         /* bio split */
8272         ASSERT(map_length <= INT_MAX);
8273         atomic_inc(&dip->pending_bios);
8274         do {
8275                 clone_len = min_t(int, submit_len, map_length);
8276
8277                 /*
8278                  * This will never fail as it's passing GPF_NOFS and
8279                  * the allocation is backed by btrfs_bioset.
8280                  */
8281                 bio = btrfs_bio_clone_partial(orig_bio, clone_offset,
8282                                               clone_len);
8283                 bio->bi_private = dip;
8284                 bio->bi_end_io = btrfs_end_dio_bio;
8285                 btrfs_io_bio(bio)->logical = file_offset;
8286
8287                 ASSERT(submit_len >= clone_len);
8288                 submit_len -= clone_len;
8289                 if (submit_len == 0)
8290                         break;
8291
8292                 /*
8293                  * Increase the count before we submit the bio so we know
8294                  * the end IO handler won't happen before we increase the
8295                  * count. Otherwise, the dip might get freed before we're
8296                  * done setting it up.
8297                  */
8298                 atomic_inc(&dip->pending_bios);
8299
8300                 status = btrfs_submit_dio_bio(bio, inode, file_offset,
8301                                                 async_submit);
8302                 if (status) {
8303                         bio_put(bio);
8304                         atomic_dec(&dip->pending_bios);
8305                         goto out_err;
8306                 }
8307
8308                 clone_offset += clone_len;
8309                 start_sector += clone_len >> 9;
8310                 file_offset += clone_len;
8311
8312                 map_length = submit_len;
8313                 ret = btrfs_map_block(fs_info, btrfs_op(orig_bio),
8314                                       start_sector << 9, &map_length, NULL, 0);
8315                 if (ret)
8316                         goto out_err;
8317         } while (submit_len > 0);
8318
8319 submit:
8320         status = btrfs_submit_dio_bio(bio, inode, file_offset, async_submit);
8321         if (!status)
8322                 return 0;
8323
8324         bio_put(bio);
8325 out_err:
8326         dip->errors = 1;
8327         /*
8328          * Before atomic variable goto zero, we must  make sure dip->errors is
8329          * perceived to be set. This ordering is ensured by the fact that an
8330          * atomic operations with a return value are fully ordered as per
8331          * atomic_t.txt
8332          */
8333         if (atomic_dec_and_test(&dip->pending_bios))
8334                 bio_io_error(dip->orig_bio);
8335
8336         /* bio_end_io() will handle error, so we needn't return it */
8337         return 0;
8338 }
8339
8340 static void btrfs_submit_direct(struct bio *dio_bio, struct inode *inode,
8341                                 loff_t file_offset)
8342 {
8343         struct btrfs_dio_private *dip = NULL;
8344         struct bio *bio = NULL;
8345         struct btrfs_io_bio *io_bio;
8346         bool write = (bio_op(dio_bio) == REQ_OP_WRITE);
8347         int ret = 0;
8348
8349         bio = btrfs_bio_clone(dio_bio);
8350
8351         dip = kzalloc(sizeof(*dip), GFP_NOFS);
8352         if (!dip) {
8353                 ret = -ENOMEM;
8354                 goto free_ordered;
8355         }
8356
8357         dip->private = dio_bio->bi_private;
8358         dip->inode = inode;
8359         dip->logical_offset = file_offset;
8360         dip->bytes = dio_bio->bi_iter.bi_size;
8361         dip->disk_bytenr = (u64)dio_bio->bi_iter.bi_sector << 9;
8362         bio->bi_private = dip;
8363         dip->orig_bio = bio;
8364         dip->dio_bio = dio_bio;
8365         atomic_set(&dip->pending_bios, 0);
8366         io_bio = btrfs_io_bio(bio);
8367         io_bio->logical = file_offset;
8368
8369         if (write) {
8370                 bio->bi_end_io = btrfs_endio_direct_write;
8371         } else {
8372                 bio->bi_end_io = btrfs_endio_direct_read;
8373                 dip->subio_endio = btrfs_subio_endio_read;
8374         }
8375
8376         /*
8377          * Reset the range for unsubmitted ordered extents (to a 0 length range)
8378          * even if we fail to submit a bio, because in such case we do the
8379          * corresponding error handling below and it must not be done a second
8380          * time by btrfs_direct_IO().
8381          */
8382         if (write) {
8383                 struct btrfs_dio_data *dio_data = current->journal_info;
8384
8385                 dio_data->unsubmitted_oe_range_end = dip->logical_offset +
8386                         dip->bytes;
8387                 dio_data->unsubmitted_oe_range_start =
8388                         dio_data->unsubmitted_oe_range_end;
8389         }
8390
8391         ret = btrfs_submit_direct_hook(dip);
8392         if (!ret)
8393                 return;
8394
8395         if (io_bio->end_io)
8396                 io_bio->end_io(io_bio, ret);
8397
8398 free_ordered:
8399         /*
8400          * If we arrived here it means either we failed to submit the dip
8401          * or we either failed to clone the dio_bio or failed to allocate the
8402          * dip. If we cloned the dio_bio and allocated the dip, we can just
8403          * call bio_endio against our io_bio so that we get proper resource
8404          * cleanup if we fail to submit the dip, otherwise, we must do the
8405          * same as btrfs_endio_direct_[write|read] because we can't call these
8406          * callbacks - they require an allocated dip and a clone of dio_bio.
8407          */
8408         if (bio && dip) {
8409                 bio_io_error(bio);
8410                 /*
8411                  * The end io callbacks free our dip, do the final put on bio
8412                  * and all the cleanup and final put for dio_bio (through
8413                  * dio_end_io()).
8414                  */
8415                 dip = NULL;
8416                 bio = NULL;
8417         } else {
8418                 if (write)
8419                         __endio_write_update_ordered(inode,
8420                                                 file_offset,
8421                                                 dio_bio->bi_iter.bi_size,
8422                                                 false);
8423                 else
8424                         unlock_extent(&BTRFS_I(inode)->io_tree, file_offset,
8425                               file_offset + dio_bio->bi_iter.bi_size - 1);
8426
8427                 dio_bio->bi_status = BLK_STS_IOERR;
8428                 /*
8429                  * Releases and cleans up our dio_bio, no need to bio_put()
8430                  * nor bio_endio()/bio_io_error() against dio_bio.
8431                  */
8432                 dio_end_io(dio_bio);
8433         }
8434         if (bio)
8435                 bio_put(bio);
8436         kfree(dip);
8437 }
8438
8439 static ssize_t check_direct_IO(struct btrfs_fs_info *fs_info,
8440                                const struct iov_iter *iter, loff_t offset)
8441 {
8442         int seg;
8443         int i;
8444         unsigned int blocksize_mask = fs_info->sectorsize - 1;
8445         ssize_t retval = -EINVAL;
8446
8447         if (offset & blocksize_mask)
8448                 goto out;
8449
8450         if (iov_iter_alignment(iter) & blocksize_mask)
8451                 goto out;
8452
8453         /* If this is a write we don't need to check anymore */
8454         if (iov_iter_rw(iter) != READ || !iter_is_iovec(iter))
8455                 return 0;
8456         /*
8457          * Check to make sure we don't have duplicate iov_base's in this
8458          * iovec, if so return EINVAL, otherwise we'll get csum errors
8459          * when reading back.
8460          */
8461         for (seg = 0; seg < iter->nr_segs; seg++) {
8462                 for (i = seg + 1; i < iter->nr_segs; i++) {
8463                         if (iter->iov[seg].iov_base == iter->iov[i].iov_base)
8464                                 goto out;
8465                 }
8466         }
8467         retval = 0;
8468 out:
8469         return retval;
8470 }
8471
8472 static ssize_t btrfs_direct_IO(struct kiocb *iocb, struct iov_iter *iter)
8473 {
8474         struct file *file = iocb->ki_filp;
8475         struct inode *inode = file->f_mapping->host;
8476         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
8477         struct btrfs_dio_data dio_data = { 0 };
8478         struct extent_changeset *data_reserved = NULL;
8479         loff_t offset = iocb->ki_pos;
8480         size_t count = 0;
8481         int flags = 0;
8482         bool wakeup = true;
8483         bool relock = false;
8484         ssize_t ret;
8485
8486         if (check_direct_IO(fs_info, iter, offset))
8487                 return 0;
8488
8489         inode_dio_begin(inode);
8490
8491         /*
8492          * The generic stuff only does filemap_write_and_wait_range, which
8493          * isn't enough if we've written compressed pages to this area, so
8494          * we need to flush the dirty pages again to make absolutely sure
8495          * that any outstanding dirty pages are on disk.
8496          */
8497         count = iov_iter_count(iter);
8498         if (test_bit(BTRFS_INODE_HAS_ASYNC_EXTENT,
8499                      &BTRFS_I(inode)->runtime_flags))
8500                 filemap_fdatawrite_range(inode->i_mapping, offset,
8501                                          offset + count - 1);
8502
8503         if (iov_iter_rw(iter) == WRITE) {
8504                 /*
8505                  * If the write DIO is beyond the EOF, we need update
8506                  * the isize, but it is protected by i_mutex. So we can
8507                  * not unlock the i_mutex at this case.
8508                  */
8509                 if (offset + count <= inode->i_size) {
8510                         dio_data.overwrite = 1;
8511                         inode_unlock(inode);
8512                         relock = true;
8513                 } else if (iocb->ki_flags & IOCB_NOWAIT) {
8514                         ret = -EAGAIN;
8515                         goto out;
8516                 }
8517                 ret = btrfs_delalloc_reserve_space(inode, &data_reserved,
8518                                                    offset, count);
8519                 if (ret)
8520                         goto out;
8521
8522                 /*
8523                  * We need to know how many extents we reserved so that we can
8524                  * do the accounting properly if we go over the number we
8525                  * originally calculated.  Abuse current->journal_info for this.
8526                  */
8527                 dio_data.reserve = round_up(count,
8528                                             fs_info->sectorsize);
8529                 dio_data.unsubmitted_oe_range_start = (u64)offset;
8530                 dio_data.unsubmitted_oe_range_end = (u64)offset;
8531                 current->journal_info = &dio_data;
8532                 down_read(&BTRFS_I(inode)->dio_sem);
8533         } else if (test_bit(BTRFS_INODE_READDIO_NEED_LOCK,
8534                                      &BTRFS_I(inode)->runtime_flags)) {
8535                 inode_dio_end(inode);
8536                 flags = DIO_LOCKING | DIO_SKIP_HOLES;
8537                 wakeup = false;
8538         }
8539
8540         ret = __blockdev_direct_IO(iocb, inode,
8541                                    fs_info->fs_devices->latest_bdev,
8542                                    iter, btrfs_get_blocks_direct, NULL,
8543                                    btrfs_submit_direct, flags);
8544         if (iov_iter_rw(iter) == WRITE) {
8545                 up_read(&BTRFS_I(inode)->dio_sem);
8546                 current->journal_info = NULL;
8547                 if (ret < 0 && ret != -EIOCBQUEUED) {
8548                         if (dio_data.reserve)
8549                                 btrfs_delalloc_release_space(inode, data_reserved,
8550                                         offset, dio_data.reserve, true);
8551                         /*
8552                          * On error we might have left some ordered extents
8553                          * without submitting corresponding bios for them, so
8554                          * cleanup them up to avoid other tasks getting them
8555                          * and waiting for them to complete forever.
8556                          */
8557                         if (dio_data.unsubmitted_oe_range_start <
8558                             dio_data.unsubmitted_oe_range_end)
8559                                 __endio_write_update_ordered(inode,
8560                                         dio_data.unsubmitted_oe_range_start,
8561                                         dio_data.unsubmitted_oe_range_end -
8562                                         dio_data.unsubmitted_oe_range_start,
8563                                         false);
8564                 } else if (ret >= 0 && (size_t)ret < count)
8565                         btrfs_delalloc_release_space(inode, data_reserved,
8566                                         offset, count - (size_t)ret, true);
8567                 btrfs_delalloc_release_extents(BTRFS_I(inode), count, false);
8568         }
8569 out:
8570         if (wakeup)
8571                 inode_dio_end(inode);
8572         if (relock)
8573                 inode_lock(inode);
8574
8575         extent_changeset_free(data_reserved);
8576         return ret;
8577 }
8578
8579 #define BTRFS_FIEMAP_FLAGS      (FIEMAP_FLAG_SYNC)
8580
8581 static int btrfs_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
8582                 __u64 start, __u64 len)
8583 {
8584         int     ret;
8585
8586         ret = fiemap_check_flags(fieinfo, BTRFS_FIEMAP_FLAGS);
8587         if (ret)
8588                 return ret;
8589
8590         return extent_fiemap(inode, fieinfo, start, len);
8591 }
8592
8593 int btrfs_readpage(struct file *file, struct page *page)
8594 {
8595         struct extent_io_tree *tree;
8596         tree = &BTRFS_I(page->mapping->host)->io_tree;
8597         return extent_read_full_page(tree, page, btrfs_get_extent, 0);
8598 }
8599
8600 static int btrfs_writepage(struct page *page, struct writeback_control *wbc)
8601 {
8602         struct inode *inode = page->mapping->host;
8603         int ret;
8604
8605         if (current->flags & PF_MEMALLOC) {
8606                 redirty_page_for_writepage(wbc, page);
8607                 unlock_page(page);
8608                 return 0;
8609         }
8610
8611         /*
8612          * If we are under memory pressure we will call this directly from the
8613          * VM, we need to make sure we have the inode referenced for the ordered
8614          * extent.  If not just return like we didn't do anything.
8615          */
8616         if (!igrab(inode)) {
8617                 redirty_page_for_writepage(wbc, page);
8618                 return AOP_WRITEPAGE_ACTIVATE;
8619         }
8620         ret = extent_write_full_page(page, wbc);
8621         btrfs_add_delayed_iput(inode);
8622         return ret;
8623 }
8624
8625 static int btrfs_writepages(struct address_space *mapping,
8626                             struct writeback_control *wbc)
8627 {
8628         return extent_writepages(mapping, wbc);
8629 }
8630
8631 static int
8632 btrfs_readpages(struct file *file, struct address_space *mapping,
8633                 struct list_head *pages, unsigned nr_pages)
8634 {
8635         return extent_readpages(mapping, pages, nr_pages);
8636 }
8637
8638 static int __btrfs_releasepage(struct page *page, gfp_t gfp_flags)
8639 {
8640         int ret = try_release_extent_mapping(page, gfp_flags);
8641         if (ret == 1) {
8642                 ClearPagePrivate(page);
8643                 set_page_private(page, 0);
8644                 put_page(page);
8645         }
8646         return ret;
8647 }
8648
8649 static int btrfs_releasepage(struct page *page, gfp_t gfp_flags)
8650 {
8651         if (PageWriteback(page) || PageDirty(page))
8652                 return 0;
8653         return __btrfs_releasepage(page, gfp_flags);
8654 }
8655
8656 static void btrfs_invalidatepage(struct page *page, unsigned int offset,
8657                                  unsigned int length)
8658 {
8659         struct inode *inode = page->mapping->host;
8660         struct extent_io_tree *tree;
8661         struct btrfs_ordered_extent *ordered;
8662         struct extent_state *cached_state = NULL;
8663         u64 page_start = page_offset(page);
8664         u64 page_end = page_start + PAGE_SIZE - 1;
8665         u64 start;
8666         u64 end;
8667         int inode_evicting = inode->i_state & I_FREEING;
8668
8669         /*
8670          * we have the page locked, so new writeback can't start,
8671          * and the dirty bit won't be cleared while we are here.
8672          *
8673          * Wait for IO on this page so that we can safely clear
8674          * the PagePrivate2 bit and do ordered accounting
8675          */
8676         wait_on_page_writeback(page);
8677
8678         tree = &BTRFS_I(inode)->io_tree;
8679         if (offset) {
8680                 btrfs_releasepage(page, GFP_NOFS);
8681                 return;
8682         }
8683
8684         if (!inode_evicting)
8685                 lock_extent_bits(tree, page_start, page_end, &cached_state);
8686 again:
8687         start = page_start;
8688         ordered = btrfs_lookup_ordered_range(BTRFS_I(inode), start,
8689                                         page_end - start + 1);
8690         if (ordered) {
8691                 end = min(page_end, ordered->file_offset + ordered->len - 1);
8692                 /*
8693                  * IO on this page will never be started, so we need
8694                  * to account for any ordered extents now
8695                  */
8696                 if (!inode_evicting)
8697                         clear_extent_bit(tree, start, end,
8698                                          EXTENT_DIRTY | EXTENT_DELALLOC |
8699                                          EXTENT_DELALLOC_NEW |
8700                                          EXTENT_LOCKED | EXTENT_DO_ACCOUNTING |
8701                                          EXTENT_DEFRAG, 1, 0, &cached_state);
8702                 /*
8703                  * whoever cleared the private bit is responsible
8704                  * for the finish_ordered_io
8705                  */
8706                 if (TestClearPagePrivate2(page)) {
8707                         struct btrfs_ordered_inode_tree *tree;
8708                         u64 new_len;
8709
8710                         tree = &BTRFS_I(inode)->ordered_tree;
8711
8712                         spin_lock_irq(&tree->lock);
8713                         set_bit(BTRFS_ORDERED_TRUNCATED, &ordered->flags);
8714                         new_len = start - ordered->file_offset;
8715                         if (new_len < ordered->truncated_len)
8716                                 ordered->truncated_len = new_len;
8717                         spin_unlock_irq(&tree->lock);
8718
8719                         if (btrfs_dec_test_ordered_pending(inode, &ordered,
8720                                                            start,
8721                                                            end - start + 1, 1))
8722                                 btrfs_finish_ordered_io(ordered);
8723                 }
8724                 btrfs_put_ordered_extent(ordered);
8725                 if (!inode_evicting) {
8726                         cached_state = NULL;
8727                         lock_extent_bits(tree, start, end,
8728                                          &cached_state);
8729                 }
8730
8731                 start = end + 1;
8732                 if (start < page_end)
8733                         goto again;
8734         }
8735
8736         /*
8737          * Qgroup reserved space handler
8738          * Page here will be either
8739          * 1) Already written to disk
8740          *    In this case, its reserved space is released from data rsv map
8741          *    and will be freed by delayed_ref handler finally.
8742          *    So even we call qgroup_free_data(), it won't decrease reserved
8743          *    space.
8744          * 2) Not written to disk
8745          *    This means the reserved space should be freed here. However,
8746          *    if a truncate invalidates the page (by clearing PageDirty)
8747          *    and the page is accounted for while allocating extent
8748          *    in btrfs_check_data_free_space() we let delayed_ref to
8749          *    free the entire extent.
8750          */
8751         if (PageDirty(page))
8752                 btrfs_qgroup_free_data(inode, NULL, page_start, PAGE_SIZE);
8753         if (!inode_evicting) {
8754                 clear_extent_bit(tree, page_start, page_end,
8755                                  EXTENT_LOCKED | EXTENT_DIRTY |
8756                                  EXTENT_DELALLOC | EXTENT_DELALLOC_NEW |
8757                                  EXTENT_DO_ACCOUNTING | EXTENT_DEFRAG, 1, 1,
8758                                  &cached_state);
8759
8760                 __btrfs_releasepage(page, GFP_NOFS);
8761         }
8762
8763         ClearPageChecked(page);
8764         if (PagePrivate(page)) {
8765                 ClearPagePrivate(page);
8766                 set_page_private(page, 0);
8767                 put_page(page);
8768         }
8769 }
8770
8771 /*
8772  * btrfs_page_mkwrite() is not allowed to change the file size as it gets
8773  * called from a page fault handler when a page is first dirtied. Hence we must
8774  * be careful to check for EOF conditions here. We set the page up correctly
8775  * for a written page which means we get ENOSPC checking when writing into
8776  * holes and correct delalloc and unwritten extent mapping on filesystems that
8777  * support these features.
8778  *
8779  * We are not allowed to take the i_mutex here so we have to play games to
8780  * protect against truncate races as the page could now be beyond EOF.  Because
8781  * truncate_setsize() writes the inode size before removing pages, once we have
8782  * the page lock we can determine safely if the page is beyond EOF. If it is not
8783  * beyond EOF, then the page is guaranteed safe against truncation until we
8784  * unlock the page.
8785  */
8786 vm_fault_t btrfs_page_mkwrite(struct vm_fault *vmf)
8787 {
8788         struct page *page = vmf->page;
8789         struct inode *inode = file_inode(vmf->vma->vm_file);
8790         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
8791         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
8792         struct btrfs_ordered_extent *ordered;
8793         struct extent_state *cached_state = NULL;
8794         struct extent_changeset *data_reserved = NULL;
8795         char *kaddr;
8796         unsigned long zero_start;
8797         loff_t size;
8798         vm_fault_t ret;
8799         int ret2;
8800         int reserved = 0;
8801         u64 reserved_space;
8802         u64 page_start;
8803         u64 page_end;
8804         u64 end;
8805
8806         reserved_space = PAGE_SIZE;
8807
8808         sb_start_pagefault(inode->i_sb);
8809         page_start = page_offset(page);
8810         page_end = page_start + PAGE_SIZE - 1;
8811         end = page_end;
8812
8813         /*
8814          * Reserving delalloc space after obtaining the page lock can lead to
8815          * deadlock. For example, if a dirty page is locked by this function
8816          * and the call to btrfs_delalloc_reserve_space() ends up triggering
8817          * dirty page write out, then the btrfs_writepage() function could
8818          * end up waiting indefinitely to get a lock on the page currently
8819          * being processed by btrfs_page_mkwrite() function.
8820          */
8821         ret2 = btrfs_delalloc_reserve_space(inode, &data_reserved, page_start,
8822                                            reserved_space);
8823         if (!ret2) {
8824                 ret2 = file_update_time(vmf->vma->vm_file);
8825                 reserved = 1;
8826         }
8827         if (ret2) {
8828                 ret = vmf_error(ret2);
8829                 if (reserved)
8830                         goto out;
8831                 goto out_noreserve;
8832         }
8833
8834         ret = VM_FAULT_NOPAGE; /* make the VM retry the fault */
8835 again:
8836         lock_page(page);
8837         size = i_size_read(inode);
8838
8839         if ((page->mapping != inode->i_mapping) ||
8840             (page_start >= size)) {
8841                 /* page got truncated out from underneath us */
8842                 goto out_unlock;
8843         }
8844         wait_on_page_writeback(page);
8845
8846         lock_extent_bits(io_tree, page_start, page_end, &cached_state);
8847         set_page_extent_mapped(page);
8848
8849         /*
8850          * we can't set the delalloc bits if there are pending ordered
8851          * extents.  Drop our locks and wait for them to finish
8852          */
8853         ordered = btrfs_lookup_ordered_range(BTRFS_I(inode), page_start,
8854                         PAGE_SIZE);
8855         if (ordered) {
8856                 unlock_extent_cached(io_tree, page_start, page_end,
8857                                      &cached_state);
8858                 unlock_page(page);
8859                 btrfs_start_ordered_extent(inode, ordered, 1);
8860                 btrfs_put_ordered_extent(ordered);
8861                 goto again;
8862         }
8863
8864         if (page->index == ((size - 1) >> PAGE_SHIFT)) {
8865                 reserved_space = round_up(size - page_start,
8866                                           fs_info->sectorsize);
8867                 if (reserved_space < PAGE_SIZE) {
8868                         end = page_start + reserved_space - 1;
8869                         btrfs_delalloc_release_space(inode, data_reserved,
8870                                         page_start, PAGE_SIZE - reserved_space,
8871                                         true);
8872                 }
8873         }
8874
8875         /*
8876          * page_mkwrite gets called when the page is firstly dirtied after it's
8877          * faulted in, but write(2) could also dirty a page and set delalloc
8878          * bits, thus in this case for space account reason, we still need to
8879          * clear any delalloc bits within this page range since we have to
8880          * reserve data&meta space before lock_page() (see above comments).
8881          */
8882         clear_extent_bit(&BTRFS_I(inode)->io_tree, page_start, end,
8883                           EXTENT_DIRTY | EXTENT_DELALLOC |
8884                           EXTENT_DO_ACCOUNTING | EXTENT_DEFRAG,
8885                           0, 0, &cached_state);
8886
8887         ret2 = btrfs_set_extent_delalloc(inode, page_start, end, 0,
8888                                         &cached_state, 0);
8889         if (ret2) {
8890                 unlock_extent_cached(io_tree, page_start, page_end,
8891                                      &cached_state);
8892                 ret = VM_FAULT_SIGBUS;
8893                 goto out_unlock;
8894         }
8895         ret2 = 0;
8896
8897         /* page is wholly or partially inside EOF */
8898         if (page_start + PAGE_SIZE > size)
8899                 zero_start = size & ~PAGE_MASK;
8900         else
8901                 zero_start = PAGE_SIZE;
8902
8903         if (zero_start != PAGE_SIZE) {
8904                 kaddr = kmap(page);
8905                 memset(kaddr + zero_start, 0, PAGE_SIZE - zero_start);
8906                 flush_dcache_page(page);
8907                 kunmap(page);
8908         }
8909         ClearPageChecked(page);
8910         set_page_dirty(page);
8911         SetPageUptodate(page);
8912
8913         BTRFS_I(inode)->last_trans = fs_info->generation;
8914         BTRFS_I(inode)->last_sub_trans = BTRFS_I(inode)->root->log_transid;
8915         BTRFS_I(inode)->last_log_commit = BTRFS_I(inode)->root->last_log_commit;
8916
8917         unlock_extent_cached(io_tree, page_start, page_end, &cached_state);
8918
8919         if (!ret2) {
8920                 btrfs_delalloc_release_extents(BTRFS_I(inode), PAGE_SIZE, true);
8921                 sb_end_pagefault(inode->i_sb);
8922                 extent_changeset_free(data_reserved);
8923                 return VM_FAULT_LOCKED;
8924         }
8925
8926 out_unlock:
8927         unlock_page(page);
8928 out:
8929         btrfs_delalloc_release_extents(BTRFS_I(inode), PAGE_SIZE, (ret != 0));
8930         btrfs_delalloc_release_space(inode, data_reserved, page_start,
8931                                      reserved_space, (ret != 0));
8932 out_noreserve:
8933         sb_end_pagefault(inode->i_sb);
8934         extent_changeset_free(data_reserved);
8935         return ret;
8936 }
8937
8938 static int btrfs_truncate(struct inode *inode, bool skip_writeback)
8939 {
8940         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
8941         struct btrfs_root *root = BTRFS_I(inode)->root;
8942         struct btrfs_block_rsv *rsv;
8943         int ret;
8944         struct btrfs_trans_handle *trans;
8945         u64 mask = fs_info->sectorsize - 1;
8946         u64 min_size = btrfs_calc_trunc_metadata_size(fs_info, 1);
8947
8948         if (!skip_writeback) {
8949                 ret = btrfs_wait_ordered_range(inode, inode->i_size & (~mask),
8950                                                (u64)-1);
8951                 if (ret)
8952                         return ret;
8953         }
8954
8955         /*
8956          * Yes ladies and gentlemen, this is indeed ugly.  We have a couple of
8957          * things going on here:
8958          *
8959          * 1) We need to reserve space to update our inode.
8960          *
8961          * 2) We need to have something to cache all the space that is going to
8962          * be free'd up by the truncate operation, but also have some slack
8963          * space reserved in case it uses space during the truncate (thank you
8964          * very much snapshotting).
8965          *
8966          * And we need these to be separate.  The fact is we can use a lot of
8967          * space doing the truncate, and we have no earthly idea how much space
8968          * we will use, so we need the truncate reservation to be separate so it
8969          * doesn't end up using space reserved for updating the inode.  We also
8970          * need to be able to stop the transaction and start a new one, which
8971          * means we need to be able to update the inode several times, and we
8972          * have no idea of knowing how many times that will be, so we can't just
8973          * reserve 1 item for the entirety of the operation, so that has to be
8974          * done separately as well.
8975          *
8976          * So that leaves us with
8977          *
8978          * 1) rsv - for the truncate reservation, which we will steal from the
8979          * transaction reservation.
8980          * 2) fs_info->trans_block_rsv - this will have 1 items worth left for
8981          * updating the inode.
8982          */
8983         rsv = btrfs_alloc_block_rsv(fs_info, BTRFS_BLOCK_RSV_TEMP);
8984         if (!rsv)
8985                 return -ENOMEM;
8986         rsv->size = min_size;
8987         rsv->failfast = 1;
8988
8989         /*
8990          * 1 for the truncate slack space
8991          * 1 for updating the inode.
8992          */
8993         trans = btrfs_start_transaction(root, 2);
8994         if (IS_ERR(trans)) {
8995                 ret = PTR_ERR(trans);
8996                 goto out;
8997         }
8998
8999         /* Migrate the slack space for the truncate to our reserve */
9000         ret = btrfs_block_rsv_migrate(&fs_info->trans_block_rsv, rsv,
9001                                       min_size, false);
9002         BUG_ON(ret);
9003
9004         /*
9005          * So if we truncate and then write and fsync we normally would just
9006          * write the extents that changed, which is a problem if we need to
9007          * first truncate that entire inode.  So set this flag so we write out
9008          * all of the extents in the inode to the sync log so we're completely
9009          * safe.
9010          */
9011         set_bit(BTRFS_INODE_NEEDS_FULL_SYNC, &BTRFS_I(inode)->runtime_flags);
9012         trans->block_rsv = rsv;
9013
9014         while (1) {
9015                 ret = btrfs_truncate_inode_items(trans, root, inode,
9016                                                  inode->i_size,
9017                                                  BTRFS_EXTENT_DATA_KEY);
9018                 trans->block_rsv = &fs_info->trans_block_rsv;
9019                 if (ret != -ENOSPC && ret != -EAGAIN)
9020                         break;
9021
9022                 ret = btrfs_update_inode(trans, root, inode);
9023                 if (ret)
9024                         break;
9025
9026                 btrfs_end_transaction(trans);
9027                 btrfs_btree_balance_dirty(fs_info);
9028
9029                 trans = btrfs_start_transaction(root, 2);
9030                 if (IS_ERR(trans)) {
9031                         ret = PTR_ERR(trans);
9032                         trans = NULL;
9033                         break;
9034                 }
9035
9036                 btrfs_block_rsv_release(fs_info, rsv, -1);
9037                 ret = btrfs_block_rsv_migrate(&fs_info->trans_block_rsv,
9038                                               rsv, min_size, false);
9039                 BUG_ON(ret);    /* shouldn't happen */
9040                 trans->block_rsv = rsv;
9041         }
9042
9043         /*
9044          * We can't call btrfs_truncate_block inside a trans handle as we could
9045          * deadlock with freeze, if we got NEED_TRUNCATE_BLOCK then we know
9046          * we've truncated everything except the last little bit, and can do
9047          * btrfs_truncate_block and then update the disk_i_size.
9048          */
9049         if (ret == NEED_TRUNCATE_BLOCK) {
9050                 btrfs_end_transaction(trans);
9051                 btrfs_btree_balance_dirty(fs_info);
9052
9053                 ret = btrfs_truncate_block(inode, inode->i_size, 0, 0);
9054                 if (ret)
9055                         goto out;
9056                 trans = btrfs_start_transaction(root, 1);
9057                 if (IS_ERR(trans)) {
9058                         ret = PTR_ERR(trans);
9059                         goto out;
9060                 }
9061                 btrfs_ordered_update_i_size(inode, inode->i_size, NULL);
9062         }
9063
9064         if (trans) {
9065                 int ret2;
9066
9067                 trans->block_rsv = &fs_info->trans_block_rsv;
9068                 ret2 = btrfs_update_inode(trans, root, inode);
9069                 if (ret2 && !ret)
9070                         ret = ret2;
9071
9072                 ret2 = btrfs_end_transaction(trans);
9073                 if (ret2 && !ret)
9074                         ret = ret2;
9075                 btrfs_btree_balance_dirty(fs_info);
9076         }
9077 out:
9078         btrfs_free_block_rsv(fs_info, rsv);
9079
9080         return ret;
9081 }
9082
9083 /*
9084  * create a new subvolume directory/inode (helper for the ioctl).
9085  */
9086 int btrfs_create_subvol_root(struct btrfs_trans_handle *trans,
9087                              struct btrfs_root *new_root,
9088                              struct btrfs_root *parent_root,
9089                              u64 new_dirid)
9090 {
9091         struct inode *inode;
9092         int err;
9093         u64 index = 0;
9094
9095         inode = btrfs_new_inode(trans, new_root, NULL, "..", 2,
9096                                 new_dirid, new_dirid,
9097                                 S_IFDIR | (~current_umask() & S_IRWXUGO),
9098                                 &index);
9099         if (IS_ERR(inode))
9100                 return PTR_ERR(inode);
9101         inode->i_op = &btrfs_dir_inode_operations;
9102         inode->i_fop = &btrfs_dir_file_operations;
9103
9104         set_nlink(inode, 1);
9105         btrfs_i_size_write(BTRFS_I(inode), 0);
9106         unlock_new_inode(inode);
9107
9108         err = btrfs_subvol_inherit_props(trans, new_root, parent_root);
9109         if (err)
9110                 btrfs_err(new_root->fs_info,
9111                           "error inheriting subvolume %llu properties: %d",
9112                           new_root->root_key.objectid, err);
9113
9114         err = btrfs_update_inode(trans, new_root, inode);
9115
9116         iput(inode);
9117         return err;
9118 }
9119
9120 struct inode *btrfs_alloc_inode(struct super_block *sb)
9121 {
9122         struct btrfs_fs_info *fs_info = btrfs_sb(sb);
9123         struct btrfs_inode *ei;
9124         struct inode *inode;
9125
9126         ei = kmem_cache_alloc(btrfs_inode_cachep, GFP_KERNEL);
9127         if (!ei)
9128                 return NULL;
9129
9130         ei->root = NULL;
9131         ei->generation = 0;
9132         ei->last_trans = 0;
9133         ei->last_sub_trans = 0;
9134         ei->logged_trans = 0;
9135         ei->delalloc_bytes = 0;
9136         ei->new_delalloc_bytes = 0;
9137         ei->defrag_bytes = 0;
9138         ei->disk_i_size = 0;
9139         ei->flags = 0;
9140         ei->csum_bytes = 0;
9141         ei->index_cnt = (u64)-1;
9142         ei->dir_index = 0;
9143         ei->last_unlink_trans = 0;
9144         ei->last_log_commit = 0;
9145
9146         spin_lock_init(&ei->lock);
9147         ei->outstanding_extents = 0;
9148         if (sb->s_magic != BTRFS_TEST_MAGIC)
9149                 btrfs_init_metadata_block_rsv(fs_info, &ei->block_rsv,
9150                                               BTRFS_BLOCK_RSV_DELALLOC);
9151         ei->runtime_flags = 0;
9152         ei->prop_compress = BTRFS_COMPRESS_NONE;
9153         ei->defrag_compress = BTRFS_COMPRESS_NONE;
9154
9155         ei->delayed_node = NULL;
9156
9157         ei->i_otime.tv_sec = 0;
9158         ei->i_otime.tv_nsec = 0;
9159
9160         inode = &ei->vfs_inode;
9161         extent_map_tree_init(&ei->extent_tree);
9162         extent_io_tree_init(&ei->io_tree, inode);
9163         extent_io_tree_init(&ei->io_failure_tree, inode);
9164         ei->io_tree.track_uptodate = 1;
9165         ei->io_failure_tree.track_uptodate = 1;
9166         atomic_set(&ei->sync_writers, 0);
9167         mutex_init(&ei->log_mutex);
9168         mutex_init(&ei->delalloc_mutex);
9169         btrfs_ordered_inode_tree_init(&ei->ordered_tree);
9170         INIT_LIST_HEAD(&ei->delalloc_inodes);
9171         INIT_LIST_HEAD(&ei->delayed_iput);
9172         RB_CLEAR_NODE(&ei->rb_node);
9173         init_rwsem(&ei->dio_sem);
9174
9175         return inode;
9176 }
9177
9178 #ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
9179 void btrfs_test_destroy_inode(struct inode *inode)
9180 {
9181         btrfs_drop_extent_cache(BTRFS_I(inode), 0, (u64)-1, 0);
9182         kmem_cache_free(btrfs_inode_cachep, BTRFS_I(inode));
9183 }
9184 #endif
9185
9186 static void btrfs_i_callback(struct rcu_head *head)
9187 {
9188         struct inode *inode = container_of(head, struct inode, i_rcu);
9189         kmem_cache_free(btrfs_inode_cachep, BTRFS_I(inode));
9190 }
9191
9192 void btrfs_destroy_inode(struct inode *inode)
9193 {
9194         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
9195         struct btrfs_ordered_extent *ordered;
9196         struct btrfs_root *root = BTRFS_I(inode)->root;
9197
9198         WARN_ON(!hlist_empty(&inode->i_dentry));
9199         WARN_ON(inode->i_data.nrpages);
9200         WARN_ON(BTRFS_I(inode)->block_rsv.reserved);
9201         WARN_ON(BTRFS_I(inode)->block_rsv.size);
9202         WARN_ON(BTRFS_I(inode)->outstanding_extents);
9203         WARN_ON(BTRFS_I(inode)->delalloc_bytes);
9204         WARN_ON(BTRFS_I(inode)->new_delalloc_bytes);
9205         WARN_ON(BTRFS_I(inode)->csum_bytes);
9206         WARN_ON(BTRFS_I(inode)->defrag_bytes);
9207
9208         /*
9209          * This can happen where we create an inode, but somebody else also
9210          * created the same inode and we need to destroy the one we already
9211          * created.
9212          */
9213         if (!root)
9214                 goto free;
9215
9216         while (1) {
9217                 ordered = btrfs_lookup_first_ordered_extent(inode, (u64)-1);
9218                 if (!ordered)
9219                         break;
9220                 else {
9221                         btrfs_err(fs_info,
9222                                   "found ordered extent %llu %llu on inode cleanup",
9223                                   ordered->file_offset, ordered->len);
9224                         btrfs_remove_ordered_extent(inode, ordered);
9225                         btrfs_put_ordered_extent(ordered);
9226                         btrfs_put_ordered_extent(ordered);
9227                 }
9228         }
9229         btrfs_qgroup_check_reserved_leak(inode);
9230         inode_tree_del(inode);
9231         btrfs_drop_extent_cache(BTRFS_I(inode), 0, (u64)-1, 0);
9232 free:
9233         call_rcu(&inode->i_rcu, btrfs_i_callback);
9234 }
9235
9236 int btrfs_drop_inode(struct inode *inode)
9237 {
9238         struct btrfs_root *root = BTRFS_I(inode)->root;
9239
9240         if (root == NULL)
9241                 return 1;
9242
9243         /* the snap/subvol tree is on deleting */
9244         if (btrfs_root_refs(&root->root_item) == 0)
9245                 return 1;
9246         else
9247                 return generic_drop_inode(inode);
9248 }
9249
9250 static void init_once(void *foo)
9251 {
9252         struct btrfs_inode *ei = (struct btrfs_inode *) foo;
9253
9254         inode_init_once(&ei->vfs_inode);
9255 }
9256
9257 void __cold btrfs_destroy_cachep(void)
9258 {
9259         /*
9260          * Make sure all delayed rcu free inodes are flushed before we
9261          * destroy cache.
9262          */
9263         rcu_barrier();
9264         kmem_cache_destroy(btrfs_inode_cachep);
9265         kmem_cache_destroy(btrfs_trans_handle_cachep);
9266         kmem_cache_destroy(btrfs_path_cachep);
9267         kmem_cache_destroy(btrfs_free_space_cachep);
9268 }
9269
9270 int __init btrfs_init_cachep(void)
9271 {
9272         btrfs_inode_cachep = kmem_cache_create("btrfs_inode",
9273                         sizeof(struct btrfs_inode), 0,
9274                         SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD | SLAB_ACCOUNT,
9275                         init_once);
9276         if (!btrfs_inode_cachep)
9277                 goto fail;
9278
9279         btrfs_trans_handle_cachep = kmem_cache_create("btrfs_trans_handle",
9280                         sizeof(struct btrfs_trans_handle), 0,
9281                         SLAB_TEMPORARY | SLAB_MEM_SPREAD, NULL);
9282         if (!btrfs_trans_handle_cachep)
9283                 goto fail;
9284
9285         btrfs_path_cachep = kmem_cache_create("btrfs_path",
9286                         sizeof(struct btrfs_path), 0,
9287                         SLAB_MEM_SPREAD, NULL);
9288         if (!btrfs_path_cachep)
9289                 goto fail;
9290
9291         btrfs_free_space_cachep = kmem_cache_create("btrfs_free_space",
9292                         sizeof(struct btrfs_free_space), 0,
9293                         SLAB_MEM_SPREAD, NULL);
9294         if (!btrfs_free_space_cachep)
9295                 goto fail;
9296
9297         return 0;
9298 fail:
9299         btrfs_destroy_cachep();
9300         return -ENOMEM;
9301 }
9302
9303 static int btrfs_getattr(const struct path *path, struct kstat *stat,
9304                          u32 request_mask, unsigned int flags)
9305 {
9306         u64 delalloc_bytes;
9307         struct inode *inode = d_inode(path->dentry);
9308         u32 blocksize = inode->i_sb->s_blocksize;
9309         u32 bi_flags = BTRFS_I(inode)->flags;
9310
9311         stat->result_mask |= STATX_BTIME;
9312         stat->btime.tv_sec = BTRFS_I(inode)->i_otime.tv_sec;
9313         stat->btime.tv_nsec = BTRFS_I(inode)->i_otime.tv_nsec;
9314         if (bi_flags & BTRFS_INODE_APPEND)
9315                 stat->attributes |= STATX_ATTR_APPEND;
9316         if (bi_flags & BTRFS_INODE_COMPRESS)
9317                 stat->attributes |= STATX_ATTR_COMPRESSED;
9318         if (bi_flags & BTRFS_INODE_IMMUTABLE)
9319                 stat->attributes |= STATX_ATTR_IMMUTABLE;
9320         if (bi_flags & BTRFS_INODE_NODUMP)
9321                 stat->attributes |= STATX_ATTR_NODUMP;
9322
9323         stat->attributes_mask |= (STATX_ATTR_APPEND |
9324                                   STATX_ATTR_COMPRESSED |
9325                                   STATX_ATTR_IMMUTABLE |
9326                                   STATX_ATTR_NODUMP);
9327
9328         generic_fillattr(inode, stat);
9329         stat->dev = BTRFS_I(inode)->root->anon_dev;
9330
9331         spin_lock(&BTRFS_I(inode)->lock);
9332         delalloc_bytes = BTRFS_I(inode)->new_delalloc_bytes;
9333         spin_unlock(&BTRFS_I(inode)->lock);
9334         stat->blocks = (ALIGN(inode_get_bytes(inode), blocksize) +
9335                         ALIGN(delalloc_bytes, blocksize)) >> 9;
9336         return 0;
9337 }
9338
9339 static int btrfs_rename_exchange(struct inode *old_dir,
9340                               struct dentry *old_dentry,
9341                               struct inode *new_dir,
9342                               struct dentry *new_dentry)
9343 {
9344         struct btrfs_fs_info *fs_info = btrfs_sb(old_dir->i_sb);
9345         struct btrfs_trans_handle *trans;
9346         struct btrfs_root *root = BTRFS_I(old_dir)->root;
9347         struct btrfs_root *dest = BTRFS_I(new_dir)->root;
9348         struct inode *new_inode = new_dentry->d_inode;
9349         struct inode *old_inode = old_dentry->d_inode;
9350         struct timespec64 ctime = current_time(old_inode);
9351         struct dentry *parent;
9352         u64 old_ino = btrfs_ino(BTRFS_I(old_inode));
9353         u64 new_ino = btrfs_ino(BTRFS_I(new_inode));
9354         u64 old_idx = 0;
9355         u64 new_idx = 0;
9356         u64 root_objectid;
9357         int ret;
9358         bool root_log_pinned = false;
9359         bool dest_log_pinned = false;
9360         struct btrfs_log_ctx ctx_root;
9361         struct btrfs_log_ctx ctx_dest;
9362         bool sync_log_root = false;
9363         bool sync_log_dest = false;
9364         bool commit_transaction = false;
9365
9366         /* we only allow rename subvolume link between subvolumes */
9367         if (old_ino != BTRFS_FIRST_FREE_OBJECTID && root != dest)
9368                 return -EXDEV;
9369
9370         btrfs_init_log_ctx(&ctx_root, old_inode);
9371         btrfs_init_log_ctx(&ctx_dest, new_inode);
9372
9373         /* close the race window with snapshot create/destroy ioctl */
9374         if (old_ino == BTRFS_FIRST_FREE_OBJECTID)
9375                 down_read(&fs_info->subvol_sem);
9376         if (new_ino == BTRFS_FIRST_FREE_OBJECTID)
9377                 down_read(&fs_info->subvol_sem);
9378
9379         /*
9380          * We want to reserve the absolute worst case amount of items.  So if
9381          * both inodes are subvols and we need to unlink them then that would
9382          * require 4 item modifications, but if they are both normal inodes it
9383          * would require 5 item modifications, so we'll assume their normal
9384          * inodes.  So 5 * 2 is 10, plus 2 for the new links, so 12 total items
9385          * should cover the worst case number of items we'll modify.
9386          */
9387         trans = btrfs_start_transaction(root, 12);
9388         if (IS_ERR(trans)) {
9389                 ret = PTR_ERR(trans);
9390                 goto out_notrans;
9391         }
9392
9393         /*
9394          * We need to find a free sequence number both in the source and
9395          * in the destination directory for the exchange.
9396          */
9397         ret = btrfs_set_inode_index(BTRFS_I(new_dir), &old_idx);
9398         if (ret)
9399                 goto out_fail;
9400         ret = btrfs_set_inode_index(BTRFS_I(old_dir), &new_idx);
9401         if (ret)
9402                 goto out_fail;
9403
9404         BTRFS_I(old_inode)->dir_index = 0ULL;
9405         BTRFS_I(new_inode)->dir_index = 0ULL;
9406
9407         /* Reference for the source. */
9408         if (old_ino == BTRFS_FIRST_FREE_OBJECTID) {
9409                 /* force full log commit if subvolume involved. */
9410                 btrfs_set_log_full_commit(fs_info, trans);
9411         } else {
9412                 btrfs_pin_log_trans(root);
9413                 root_log_pinned = true;
9414                 ret = btrfs_insert_inode_ref(trans, dest,
9415                                              new_dentry->d_name.name,
9416                                              new_dentry->d_name.len,
9417                                              old_ino,
9418                                              btrfs_ino(BTRFS_I(new_dir)),
9419                                              old_idx);
9420                 if (ret)
9421                         goto out_fail;
9422         }
9423
9424         /* And now for the dest. */
9425         if (new_ino == BTRFS_FIRST_FREE_OBJECTID) {
9426                 /* force full log commit if subvolume involved. */
9427                 btrfs_set_log_full_commit(fs_info, trans);
9428         } else {
9429                 btrfs_pin_log_trans(dest);
9430                 dest_log_pinned = true;
9431                 ret = btrfs_insert_inode_ref(trans, root,
9432                                              old_dentry->d_name.name,
9433                                              old_dentry->d_name.len,
9434                                              new_ino,
9435                                              btrfs_ino(BTRFS_I(old_dir)),
9436                                              new_idx);
9437                 if (ret)
9438                         goto out_fail;
9439         }
9440
9441         /* Update inode version and ctime/mtime. */
9442         inode_inc_iversion(old_dir);
9443         inode_inc_iversion(new_dir);
9444         inode_inc_iversion(old_inode);
9445         inode_inc_iversion(new_inode);
9446         old_dir->i_ctime = old_dir->i_mtime = ctime;
9447         new_dir->i_ctime = new_dir->i_mtime = ctime;
9448         old_inode->i_ctime = ctime;
9449         new_inode->i_ctime = ctime;
9450
9451         if (old_dentry->d_parent != new_dentry->d_parent) {
9452                 btrfs_record_unlink_dir(trans, BTRFS_I(old_dir),
9453                                 BTRFS_I(old_inode), 1);
9454                 btrfs_record_unlink_dir(trans, BTRFS_I(new_dir),
9455                                 BTRFS_I(new_inode), 1);
9456         }
9457
9458         /* src is a subvolume */
9459         if (old_ino == BTRFS_FIRST_FREE_OBJECTID) {
9460                 root_objectid = BTRFS_I(old_inode)->root->root_key.objectid;
9461                 ret = btrfs_unlink_subvol(trans, old_dir, root_objectid,
9462                                           old_dentry->d_name.name,
9463                                           old_dentry->d_name.len);
9464         } else { /* src is an inode */
9465                 ret = __btrfs_unlink_inode(trans, root, BTRFS_I(old_dir),
9466                                            BTRFS_I(old_dentry->d_inode),
9467                                            old_dentry->d_name.name,
9468                                            old_dentry->d_name.len);
9469                 if (!ret)
9470                         ret = btrfs_update_inode(trans, root, old_inode);
9471         }
9472         if (ret) {
9473                 btrfs_abort_transaction(trans, ret);
9474                 goto out_fail;
9475         }
9476
9477         /* dest is a subvolume */
9478         if (new_ino == BTRFS_FIRST_FREE_OBJECTID) {
9479                 root_objectid = BTRFS_I(new_inode)->root->root_key.objectid;
9480                 ret = btrfs_unlink_subvol(trans, new_dir, root_objectid,
9481                                           new_dentry->d_name.name,
9482                                           new_dentry->d_name.len);
9483         } else { /* dest is an inode */
9484                 ret = __btrfs_unlink_inode(trans, dest, BTRFS_I(new_dir),
9485                                            BTRFS_I(new_dentry->d_inode),
9486                                            new_dentry->d_name.name,
9487                                            new_dentry->d_name.len);
9488                 if (!ret)
9489                         ret = btrfs_update_inode(trans, dest, new_inode);
9490         }
9491         if (ret) {
9492                 btrfs_abort_transaction(trans, ret);
9493                 goto out_fail;
9494         }
9495
9496         ret = btrfs_add_link(trans, BTRFS_I(new_dir), BTRFS_I(old_inode),
9497                              new_dentry->d_name.name,
9498                              new_dentry->d_name.len, 0, old_idx);
9499         if (ret) {
9500                 btrfs_abort_transaction(trans, ret);
9501                 goto out_fail;
9502         }
9503
9504         ret = btrfs_add_link(trans, BTRFS_I(old_dir), BTRFS_I(new_inode),
9505                              old_dentry->d_name.name,
9506                              old_dentry->d_name.len, 0, new_idx);
9507         if (ret) {
9508                 btrfs_abort_transaction(trans, ret);
9509                 goto out_fail;
9510         }
9511
9512         if (old_inode->i_nlink == 1)
9513                 BTRFS_I(old_inode)->dir_index = old_idx;
9514         if (new_inode->i_nlink == 1)
9515                 BTRFS_I(new_inode)->dir_index = new_idx;
9516
9517         if (root_log_pinned) {
9518                 parent = new_dentry->d_parent;
9519                 ret = btrfs_log_new_name(trans, BTRFS_I(old_inode),
9520                                          BTRFS_I(old_dir), parent,
9521                                          false, &ctx_root);
9522                 if (ret == BTRFS_NEED_LOG_SYNC)
9523                         sync_log_root = true;
9524                 else if (ret == BTRFS_NEED_TRANS_COMMIT)
9525                         commit_transaction = true;
9526                 ret = 0;
9527                 btrfs_end_log_trans(root);
9528                 root_log_pinned = false;
9529         }
9530         if (dest_log_pinned) {
9531                 if (!commit_transaction) {
9532                         parent = old_dentry->d_parent;
9533                         ret = btrfs_log_new_name(trans, BTRFS_I(new_inode),
9534                                                  BTRFS_I(new_dir), parent,
9535                                                  false, &ctx_dest);
9536                         if (ret == BTRFS_NEED_LOG_SYNC)
9537                                 sync_log_dest = true;
9538                         else if (ret == BTRFS_NEED_TRANS_COMMIT)
9539                                 commit_transaction = true;
9540                         ret = 0;
9541                 }
9542                 btrfs_end_log_trans(dest);
9543                 dest_log_pinned = false;
9544         }
9545 out_fail:
9546         /*
9547          * If we have pinned a log and an error happened, we unpin tasks
9548          * trying to sync the log and force them to fallback to a transaction
9549          * commit if the log currently contains any of the inodes involved in
9550          * this rename operation (to ensure we do not persist a log with an
9551          * inconsistent state for any of these inodes or leading to any
9552          * inconsistencies when replayed). If the transaction was aborted, the
9553          * abortion reason is propagated to userspace when attempting to commit
9554          * the transaction. If the log does not contain any of these inodes, we
9555          * allow the tasks to sync it.
9556          */
9557         if (ret && (root_log_pinned || dest_log_pinned)) {
9558                 if (btrfs_inode_in_log(BTRFS_I(old_dir), fs_info->generation) ||
9559                     btrfs_inode_in_log(BTRFS_I(new_dir), fs_info->generation) ||
9560                     btrfs_inode_in_log(BTRFS_I(old_inode), fs_info->generation) ||
9561                     (new_inode &&
9562                      btrfs_inode_in_log(BTRFS_I(new_inode), fs_info->generation)))
9563                         btrfs_set_log_full_commit(fs_info, trans);
9564
9565                 if (root_log_pinned) {
9566                         btrfs_end_log_trans(root);
9567                         root_log_pinned = false;
9568                 }
9569                 if (dest_log_pinned) {
9570                         btrfs_end_log_trans(dest);
9571                         dest_log_pinned = false;
9572                 }
9573         }
9574         if (!ret && sync_log_root && !commit_transaction) {
9575                 ret = btrfs_sync_log(trans, BTRFS_I(old_inode)->root,
9576                                      &ctx_root);
9577                 if (ret)
9578                         commit_transaction = true;
9579         }
9580         if (!ret && sync_log_dest && !commit_transaction) {
9581                 ret = btrfs_sync_log(trans, BTRFS_I(new_inode)->root,
9582                                      &ctx_dest);
9583                 if (ret)
9584                         commit_transaction = true;
9585         }
9586         if (commit_transaction) {
9587                 ret = btrfs_commit_transaction(trans);
9588         } else {
9589                 int ret2;
9590
9591                 ret2 = btrfs_end_transaction(trans);
9592                 ret = ret ? ret : ret2;
9593         }
9594 out_notrans:
9595         if (new_ino == BTRFS_FIRST_FREE_OBJECTID)
9596                 up_read(&fs_info->subvol_sem);
9597         if (old_ino == BTRFS_FIRST_FREE_OBJECTID)
9598                 up_read(&fs_info->subvol_sem);
9599
9600         return ret;
9601 }
9602
9603 static int btrfs_whiteout_for_rename(struct btrfs_trans_handle *trans,
9604                                      struct btrfs_root *root,
9605                                      struct inode *dir,
9606                                      struct dentry *dentry)
9607 {
9608         int ret;
9609         struct inode *inode;
9610         u64 objectid;
9611         u64 index;
9612
9613         ret = btrfs_find_free_ino(root, &objectid);
9614         if (ret)
9615                 return ret;
9616
9617         inode = btrfs_new_inode(trans, root, dir,
9618                                 dentry->d_name.name,
9619                                 dentry->d_name.len,
9620                                 btrfs_ino(BTRFS_I(dir)),
9621                                 objectid,
9622                                 S_IFCHR | WHITEOUT_MODE,
9623                                 &index);
9624
9625         if (IS_ERR(inode)) {
9626                 ret = PTR_ERR(inode);
9627                 return ret;
9628         }
9629
9630         inode->i_op = &btrfs_special_inode_operations;
9631         init_special_inode(inode, inode->i_mode,
9632                 WHITEOUT_DEV);
9633
9634         ret = btrfs_init_inode_security(trans, inode, dir,
9635                                 &dentry->d_name);
9636         if (ret)
9637                 goto out;
9638
9639         ret = btrfs_add_nondir(trans, BTRFS_I(dir), dentry,
9640                                 BTRFS_I(inode), 0, index);
9641         if (ret)
9642                 goto out;
9643
9644         ret = btrfs_update_inode(trans, root, inode);
9645 out:
9646         unlock_new_inode(inode);
9647         if (ret)
9648                 inode_dec_link_count(inode);
9649         iput(inode);
9650
9651         return ret;
9652 }
9653
9654 static int btrfs_rename(struct inode *old_dir, struct dentry *old_dentry,
9655                            struct inode *new_dir, struct dentry *new_dentry,
9656                            unsigned int flags)
9657 {
9658         struct btrfs_fs_info *fs_info = btrfs_sb(old_dir->i_sb);
9659         struct btrfs_trans_handle *trans;
9660         unsigned int trans_num_items;
9661         struct btrfs_root *root = BTRFS_I(old_dir)->root;
9662         struct btrfs_root *dest = BTRFS_I(new_dir)->root;
9663         struct inode *new_inode = d_inode(new_dentry);
9664         struct inode *old_inode = d_inode(old_dentry);
9665         u64 index = 0;
9666         u64 root_objectid;
9667         int ret;
9668         u64 old_ino = btrfs_ino(BTRFS_I(old_inode));
9669         bool log_pinned = false;
9670         struct btrfs_log_ctx ctx;
9671         bool sync_log = false;
9672         bool commit_transaction = false;
9673
9674         if (btrfs_ino(BTRFS_I(new_dir)) == BTRFS_EMPTY_SUBVOL_DIR_OBJECTID)
9675                 return -EPERM;
9676
9677         /* we only allow rename subvolume link between subvolumes */
9678         if (old_ino != BTRFS_FIRST_FREE_OBJECTID && root != dest)
9679                 return -EXDEV;
9680
9681         if (old_ino == BTRFS_EMPTY_SUBVOL_DIR_OBJECTID ||
9682             (new_inode && btrfs_ino(BTRFS_I(new_inode)) == BTRFS_FIRST_FREE_OBJECTID))
9683                 return -ENOTEMPTY;
9684
9685         if (S_ISDIR(old_inode->i_mode) && new_inode &&
9686             new_inode->i_size > BTRFS_EMPTY_DIR_SIZE)
9687                 return -ENOTEMPTY;
9688
9689
9690         /* check for collisions, even if the  name isn't there */
9691         ret = btrfs_check_dir_item_collision(dest, new_dir->i_ino,
9692                              new_dentry->d_name.name,
9693                              new_dentry->d_name.len);
9694
9695         if (ret) {
9696                 if (ret == -EEXIST) {
9697                         /* we shouldn't get
9698                          * eexist without a new_inode */
9699                         if (WARN_ON(!new_inode)) {
9700                                 return ret;
9701                         }
9702                 } else {
9703                         /* maybe -EOVERFLOW */
9704                         return ret;
9705                 }
9706         }
9707         ret = 0;
9708
9709         /*
9710          * we're using rename to replace one file with another.  Start IO on it
9711          * now so  we don't add too much work to the end of the transaction
9712          */
9713         if (new_inode && S_ISREG(old_inode->i_mode) && new_inode->i_size)
9714                 filemap_flush(old_inode->i_mapping);
9715
9716         /* close the racy window with snapshot create/destroy ioctl */
9717         if (old_ino == BTRFS_FIRST_FREE_OBJECTID)
9718                 down_read(&fs_info->subvol_sem);
9719         /*
9720          * We want to reserve the absolute worst case amount of items.  So if
9721          * both inodes are subvols and we need to unlink them then that would
9722          * require 4 item modifications, but if they are both normal inodes it
9723          * would require 5 item modifications, so we'll assume they are normal
9724          * inodes.  So 5 * 2 is 10, plus 1 for the new link, so 11 total items
9725          * should cover the worst case number of items we'll modify.
9726          * If our rename has the whiteout flag, we need more 5 units for the
9727          * new inode (1 inode item, 1 inode ref, 2 dir items and 1 xattr item
9728          * when selinux is enabled).
9729          */
9730         trans_num_items = 11;
9731         if (flags & RENAME_WHITEOUT)
9732                 trans_num_items += 5;
9733         trans = btrfs_start_transaction(root, trans_num_items);
9734         if (IS_ERR(trans)) {
9735                 ret = PTR_ERR(trans);
9736                 goto out_notrans;
9737         }
9738
9739         if (dest != root)
9740                 btrfs_record_root_in_trans(trans, dest);
9741
9742         ret = btrfs_set_inode_index(BTRFS_I(new_dir), &index);
9743         if (ret)
9744                 goto out_fail;
9745
9746         BTRFS_I(old_inode)->dir_index = 0ULL;
9747         if (unlikely(old_ino == BTRFS_FIRST_FREE_OBJECTID)) {
9748                 /* force full log commit if subvolume involved. */
9749                 btrfs_set_log_full_commit(fs_info, trans);
9750         } else {
9751                 btrfs_pin_log_trans(root);
9752                 log_pinned = true;
9753                 ret = btrfs_insert_inode_ref(trans, dest,
9754                                              new_dentry->d_name.name,
9755                                              new_dentry->d_name.len,
9756                                              old_ino,
9757                                              btrfs_ino(BTRFS_I(new_dir)), index);
9758                 if (ret)
9759                         goto out_fail;
9760         }
9761
9762         inode_inc_iversion(old_dir);
9763         inode_inc_iversion(new_dir);
9764         inode_inc_iversion(old_inode);
9765         old_dir->i_ctime = old_dir->i_mtime =
9766         new_dir->i_ctime = new_dir->i_mtime =
9767         old_inode->i_ctime = current_time(old_dir);
9768
9769         if (old_dentry->d_parent != new_dentry->d_parent)
9770                 btrfs_record_unlink_dir(trans, BTRFS_I(old_dir),
9771                                 BTRFS_I(old_inode), 1);
9772
9773         if (unlikely(old_ino == BTRFS_FIRST_FREE_OBJECTID)) {
9774                 root_objectid = BTRFS_I(old_inode)->root->root_key.objectid;
9775                 ret = btrfs_unlink_subvol(trans, old_dir, root_objectid,
9776                                         old_dentry->d_name.name,
9777                                         old_dentry->d_name.len);
9778         } else {
9779                 ret = __btrfs_unlink_inode(trans, root, BTRFS_I(old_dir),
9780                                         BTRFS_I(d_inode(old_dentry)),
9781                                         old_dentry->d_name.name,
9782                                         old_dentry->d_name.len);
9783                 if (!ret)
9784                         ret = btrfs_update_inode(trans, root, old_inode);
9785         }
9786         if (ret) {
9787                 btrfs_abort_transaction(trans, ret);
9788                 goto out_fail;
9789         }
9790
9791         if (new_inode) {
9792                 inode_inc_iversion(new_inode);
9793                 new_inode->i_ctime = current_time(new_inode);
9794                 if (unlikely(btrfs_ino(BTRFS_I(new_inode)) ==
9795                              BTRFS_EMPTY_SUBVOL_DIR_OBJECTID)) {
9796                         root_objectid = BTRFS_I(new_inode)->location.objectid;
9797                         ret = btrfs_unlink_subvol(trans, new_dir, root_objectid,
9798                                                 new_dentry->d_name.name,
9799                                                 new_dentry->d_name.len);
9800                         BUG_ON(new_inode->i_nlink == 0);
9801                 } else {
9802                         ret = btrfs_unlink_inode(trans, dest, BTRFS_I(new_dir),
9803                                                  BTRFS_I(d_inode(new_dentry)),
9804                                                  new_dentry->d_name.name,
9805                                                  new_dentry->d_name.len);
9806                 }
9807                 if (!ret && new_inode->i_nlink == 0)
9808                         ret = btrfs_orphan_add(trans,
9809                                         BTRFS_I(d_inode(new_dentry)));
9810                 if (ret) {
9811                         btrfs_abort_transaction(trans, ret);
9812                         goto out_fail;
9813                 }
9814         }
9815
9816         ret = btrfs_add_link(trans, BTRFS_I(new_dir), BTRFS_I(old_inode),
9817                              new_dentry->d_name.name,
9818                              new_dentry->d_name.len, 0, index);
9819         if (ret) {
9820                 btrfs_abort_transaction(trans, ret);
9821                 goto out_fail;
9822         }
9823
9824         if (old_inode->i_nlink == 1)
9825                 BTRFS_I(old_inode)->dir_index = index;
9826
9827         if (log_pinned) {
9828                 struct dentry *parent = new_dentry->d_parent;
9829
9830                 btrfs_init_log_ctx(&ctx, old_inode);
9831                 ret = btrfs_log_new_name(trans, BTRFS_I(old_inode),
9832                                          BTRFS_I(old_dir), parent,
9833                                          false, &ctx);
9834                 if (ret == BTRFS_NEED_LOG_SYNC)
9835                         sync_log = true;
9836                 else if (ret == BTRFS_NEED_TRANS_COMMIT)
9837                         commit_transaction = true;
9838                 ret = 0;
9839                 btrfs_end_log_trans(root);
9840                 log_pinned = false;
9841         }
9842
9843         if (flags & RENAME_WHITEOUT) {
9844                 ret = btrfs_whiteout_for_rename(trans, root, old_dir,
9845                                                 old_dentry);
9846
9847                 if (ret) {
9848                         btrfs_abort_transaction(trans, ret);
9849                         goto out_fail;
9850                 }
9851         }
9852 out_fail:
9853         /*
9854          * If we have pinned the log and an error happened, we unpin tasks
9855          * trying to sync the log and force them to fallback to a transaction
9856          * commit if the log currently contains any of the inodes involved in
9857          * this rename operation (to ensure we do not persist a log with an
9858          * inconsistent state for any of these inodes or leading to any
9859          * inconsistencies when replayed). If the transaction was aborted, the
9860          * abortion reason is propagated to userspace when attempting to commit
9861          * the transaction. If the log does not contain any of these inodes, we
9862          * allow the tasks to sync it.
9863          */
9864         if (ret && log_pinned) {
9865                 if (btrfs_inode_in_log(BTRFS_I(old_dir), fs_info->generation) ||
9866                     btrfs_inode_in_log(BTRFS_I(new_dir), fs_info->generation) ||
9867                     btrfs_inode_in_log(BTRFS_I(old_inode), fs_info->generation) ||
9868                     (new_inode &&
9869                      btrfs_inode_in_log(BTRFS_I(new_inode), fs_info->generation)))
9870                         btrfs_set_log_full_commit(fs_info, trans);
9871
9872                 btrfs_end_log_trans(root);
9873                 log_pinned = false;
9874         }
9875         if (!ret && sync_log) {
9876                 ret = btrfs_sync_log(trans, BTRFS_I(old_inode)->root, &ctx);
9877                 if (ret)
9878                         commit_transaction = true;
9879         }
9880         if (commit_transaction) {
9881                 ret = btrfs_commit_transaction(trans);
9882         } else {
9883                 int ret2;
9884
9885                 ret2 = btrfs_end_transaction(trans);
9886                 ret = ret ? ret : ret2;
9887         }
9888 out_notrans:
9889         if (old_ino == BTRFS_FIRST_FREE_OBJECTID)
9890                 up_read(&fs_info->subvol_sem);
9891
9892         return ret;
9893 }
9894
9895 static int btrfs_rename2(struct inode *old_dir, struct dentry *old_dentry,
9896                          struct inode *new_dir, struct dentry *new_dentry,
9897                          unsigned int flags)
9898 {
9899         if (flags & ~(RENAME_NOREPLACE | RENAME_EXCHANGE | RENAME_WHITEOUT))
9900                 return -EINVAL;
9901
9902         if (flags & RENAME_EXCHANGE)
9903                 return btrfs_rename_exchange(old_dir, old_dentry, new_dir,
9904                                           new_dentry);
9905
9906         return btrfs_rename(old_dir, old_dentry, new_dir, new_dentry, flags);
9907 }
9908
9909 struct btrfs_delalloc_work {
9910         struct inode *inode;
9911         struct completion completion;
9912         struct list_head list;
9913         struct btrfs_work work;
9914 };
9915
9916 static void btrfs_run_delalloc_work(struct btrfs_work *work)
9917 {
9918         struct btrfs_delalloc_work *delalloc_work;
9919         struct inode *inode;
9920
9921         delalloc_work = container_of(work, struct btrfs_delalloc_work,
9922                                      work);
9923         inode = delalloc_work->inode;
9924         filemap_flush(inode->i_mapping);
9925         if (test_bit(BTRFS_INODE_HAS_ASYNC_EXTENT,
9926                                 &BTRFS_I(inode)->runtime_flags))
9927                 filemap_flush(inode->i_mapping);
9928
9929         iput(inode);
9930         complete(&delalloc_work->completion);
9931 }
9932
9933 static struct btrfs_delalloc_work *btrfs_alloc_delalloc_work(struct inode *inode)
9934 {
9935         struct btrfs_delalloc_work *work;
9936
9937         work = kmalloc(sizeof(*work), GFP_NOFS);
9938         if (!work)
9939                 return NULL;
9940
9941         init_completion(&work->completion);
9942         INIT_LIST_HEAD(&work->list);
9943         work->inode = inode;
9944         WARN_ON_ONCE(!inode);
9945         btrfs_init_work(&work->work, btrfs_flush_delalloc_helper,
9946                         btrfs_run_delalloc_work, NULL, NULL);
9947
9948         return work;
9949 }
9950
9951 /*
9952  * some fairly slow code that needs optimization. This walks the list
9953  * of all the inodes with pending delalloc and forces them to disk.
9954  */
9955 static int start_delalloc_inodes(struct btrfs_root *root, int nr)
9956 {
9957         struct btrfs_inode *binode;
9958         struct inode *inode;
9959         struct btrfs_delalloc_work *work, *next;
9960         struct list_head works;
9961         struct list_head splice;
9962         int ret = 0;
9963
9964         INIT_LIST_HEAD(&works);
9965         INIT_LIST_HEAD(&splice);
9966
9967         mutex_lock(&root->delalloc_mutex);
9968         spin_lock(&root->delalloc_lock);
9969         list_splice_init(&root->delalloc_inodes, &splice);
9970         while (!list_empty(&splice)) {
9971                 binode = list_entry(splice.next, struct btrfs_inode,
9972                                     delalloc_inodes);
9973
9974                 list_move_tail(&binode->delalloc_inodes,
9975                                &root->delalloc_inodes);
9976                 inode = igrab(&binode->vfs_inode);
9977                 if (!inode) {
9978                         cond_resched_lock(&root->delalloc_lock);
9979                         continue;
9980                 }
9981                 spin_unlock(&root->delalloc_lock);
9982
9983                 work = btrfs_alloc_delalloc_work(inode);
9984                 if (!work) {
9985                         iput(inode);
9986                         ret = -ENOMEM;
9987                         goto out;
9988                 }
9989                 list_add_tail(&work->list, &works);
9990                 btrfs_queue_work(root->fs_info->flush_workers,
9991                                  &work->work);
9992                 ret++;
9993                 if (nr != -1 && ret >= nr)
9994                         goto out;
9995                 cond_resched();
9996                 spin_lock(&root->delalloc_lock);
9997         }
9998         spin_unlock(&root->delalloc_lock);
9999
10000 out:
10001         list_for_each_entry_safe(work, next, &works, list) {
10002                 list_del_init(&work->list);
10003                 wait_for_completion(&work->completion);
10004                 kfree(work);
10005         }
10006
10007         if (!list_empty(&splice)) {
10008                 spin_lock(&root->delalloc_lock);
10009                 list_splice_tail(&splice, &root->delalloc_inodes);
10010                 spin_unlock(&root->delalloc_lock);
10011         }
10012         mutex_unlock(&root->delalloc_mutex);
10013         return ret;
10014 }
10015
10016 int btrfs_start_delalloc_inodes(struct btrfs_root *root)
10017 {
10018         struct btrfs_fs_info *fs_info = root->fs_info;
10019         int ret;
10020
10021         if (test_bit(BTRFS_FS_STATE_ERROR, &fs_info->fs_state))
10022                 return -EROFS;
10023
10024         ret = start_delalloc_inodes(root, -1);
10025         if (ret > 0)
10026                 ret = 0;
10027         return ret;
10028 }
10029
10030 int btrfs_start_delalloc_roots(struct btrfs_fs_info *fs_info, int nr)
10031 {
10032         struct btrfs_root *root;
10033         struct list_head splice;
10034         int ret;
10035
10036         if (test_bit(BTRFS_FS_STATE_ERROR, &fs_info->fs_state))
10037                 return -EROFS;
10038
10039         INIT_LIST_HEAD(&splice);
10040
10041         mutex_lock(&fs_info->delalloc_root_mutex);
10042         spin_lock(&fs_info->delalloc_root_lock);
10043         list_splice_init(&fs_info->delalloc_roots, &splice);
10044         while (!list_empty(&splice) && nr) {
10045                 root = list_first_entry(&splice, struct btrfs_root,
10046                                         delalloc_root);
10047                 root = btrfs_grab_fs_root(root);
10048                 BUG_ON(!root);
10049                 list_move_tail(&root->delalloc_root,
10050                                &fs_info->delalloc_roots);
10051                 spin_unlock(&fs_info->delalloc_root_lock);
10052
10053                 ret = start_delalloc_inodes(root, nr);
10054                 btrfs_put_fs_root(root);
10055                 if (ret < 0)
10056                         goto out;
10057
10058                 if (nr != -1) {
10059                         nr -= ret;
10060                         WARN_ON(nr < 0);
10061                 }
10062                 spin_lock(&fs_info->delalloc_root_lock);
10063         }
10064         spin_unlock(&fs_info->delalloc_root_lock);
10065
10066         ret = 0;
10067 out:
10068         if (!list_empty(&splice)) {
10069                 spin_lock(&fs_info->delalloc_root_lock);
10070                 list_splice_tail(&splice, &fs_info->delalloc_roots);
10071                 spin_unlock(&fs_info->delalloc_root_lock);
10072         }
10073         mutex_unlock(&fs_info->delalloc_root_mutex);
10074         return ret;
10075 }
10076
10077 static int btrfs_symlink(struct inode *dir, struct dentry *dentry,
10078                          const char *symname)
10079 {
10080         struct btrfs_fs_info *fs_info = btrfs_sb(dir->i_sb);
10081         struct btrfs_trans_handle *trans;
10082         struct btrfs_root *root = BTRFS_I(dir)->root;
10083         struct btrfs_path *path;
10084         struct btrfs_key key;
10085         struct inode *inode = NULL;
10086         int err;
10087         u64 objectid;
10088         u64 index = 0;
10089         int name_len;
10090         int datasize;
10091         unsigned long ptr;
10092         struct btrfs_file_extent_item *ei;
10093         struct extent_buffer *leaf;
10094
10095         name_len = strlen(symname);
10096         if (name_len > BTRFS_MAX_INLINE_DATA_SIZE(fs_info))
10097                 return -ENAMETOOLONG;
10098
10099         /*
10100          * 2 items for inode item and ref
10101          * 2 items for dir items
10102          * 1 item for updating parent inode item
10103          * 1 item for the inline extent item
10104          * 1 item for xattr if selinux is on
10105          */
10106         trans = btrfs_start_transaction(root, 7);
10107         if (IS_ERR(trans))
10108                 return PTR_ERR(trans);
10109
10110         err = btrfs_find_free_ino(root, &objectid);
10111         if (err)
10112                 goto out_unlock;
10113
10114         inode = btrfs_new_inode(trans, root, dir, dentry->d_name.name,
10115                                 dentry->d_name.len, btrfs_ino(BTRFS_I(dir)),
10116                                 objectid, S_IFLNK|S_IRWXUGO, &index);
10117         if (IS_ERR(inode)) {
10118                 err = PTR_ERR(inode);
10119                 inode = NULL;
10120                 goto out_unlock;
10121         }
10122
10123         /*
10124         * If the active LSM wants to access the inode during
10125         * d_instantiate it needs these. Smack checks to see
10126         * if the filesystem supports xattrs by looking at the
10127         * ops vector.
10128         */
10129         inode->i_fop = &btrfs_file_operations;
10130         inode->i_op = &btrfs_file_inode_operations;
10131         inode->i_mapping->a_ops = &btrfs_aops;
10132         BTRFS_I(inode)->io_tree.ops = &btrfs_extent_io_ops;
10133
10134         err = btrfs_init_inode_security(trans, inode, dir, &dentry->d_name);
10135         if (err)
10136                 goto out_unlock;
10137
10138         path = btrfs_alloc_path();
10139         if (!path) {
10140                 err = -ENOMEM;
10141                 goto out_unlock;
10142         }
10143         key.objectid = btrfs_ino(BTRFS_I(inode));
10144         key.offset = 0;
10145         key.type = BTRFS_EXTENT_DATA_KEY;
10146         datasize = btrfs_file_extent_calc_inline_size(name_len);
10147         err = btrfs_insert_empty_item(trans, root, path, &key,
10148                                       datasize);
10149         if (err) {
10150                 btrfs_free_path(path);
10151                 goto out_unlock;
10152         }
10153         leaf = path->nodes[0];
10154         ei = btrfs_item_ptr(leaf, path->slots[0],
10155                             struct btrfs_file_extent_item);
10156         btrfs_set_file_extent_generation(leaf, ei, trans->transid);
10157         btrfs_set_file_extent_type(leaf, ei,
10158                                    BTRFS_FILE_EXTENT_INLINE);
10159         btrfs_set_file_extent_encryption(leaf, ei, 0);
10160         btrfs_set_file_extent_compression(leaf, ei, 0);
10161         btrfs_set_file_extent_other_encoding(leaf, ei, 0);
10162         btrfs_set_file_extent_ram_bytes(leaf, ei, name_len);
10163
10164         ptr = btrfs_file_extent_inline_start(ei);
10165         write_extent_buffer(leaf, symname, ptr, name_len);
10166         btrfs_mark_buffer_dirty(leaf);
10167         btrfs_free_path(path);
10168
10169         inode->i_op = &btrfs_symlink_inode_operations;
10170         inode_nohighmem(inode);
10171         inode->i_mapping->a_ops = &btrfs_aops;
10172         inode_set_bytes(inode, name_len);
10173         btrfs_i_size_write(BTRFS_I(inode), name_len);
10174         err = btrfs_update_inode(trans, root, inode);
10175         /*
10176          * Last step, add directory indexes for our symlink inode. This is the
10177          * last step to avoid extra cleanup of these indexes if an error happens
10178          * elsewhere above.
10179          */
10180         if (!err)
10181                 err = btrfs_add_nondir(trans, BTRFS_I(dir), dentry,
10182                                 BTRFS_I(inode), 0, index);
10183         if (err)
10184                 goto out_unlock;
10185
10186         d_instantiate_new(dentry, inode);
10187
10188 out_unlock:
10189         btrfs_end_transaction(trans);
10190         if (err && inode) {
10191                 inode_dec_link_count(inode);
10192                 discard_new_inode(inode);
10193         }
10194         btrfs_btree_balance_dirty(fs_info);
10195         return err;
10196 }
10197
10198 static int __btrfs_prealloc_file_range(struct inode *inode, int mode,
10199                                        u64 start, u64 num_bytes, u64 min_size,
10200                                        loff_t actual_len, u64 *alloc_hint,
10201                                        struct btrfs_trans_handle *trans)
10202 {
10203         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
10204         struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
10205         struct extent_map *em;
10206         struct btrfs_root *root = BTRFS_I(inode)->root;
10207         struct btrfs_key ins;
10208         u64 cur_offset = start;
10209         u64 i_size;
10210         u64 cur_bytes;
10211         u64 last_alloc = (u64)-1;
10212         int ret = 0;
10213         bool own_trans = true;
10214         u64 end = start + num_bytes - 1;
10215
10216         if (trans)
10217                 own_trans = false;
10218         while (num_bytes > 0) {
10219                 if (own_trans) {
10220                         trans = btrfs_start_transaction(root, 3);
10221                         if (IS_ERR(trans)) {
10222                                 ret = PTR_ERR(trans);
10223                                 break;
10224                         }
10225                 }
10226
10227                 cur_bytes = min_t(u64, num_bytes, SZ_256M);
10228                 cur_bytes = max(cur_bytes, min_size);
10229                 /*
10230                  * If we are severely fragmented we could end up with really
10231                  * small allocations, so if the allocator is returning small
10232                  * chunks lets make its job easier by only searching for those
10233                  * sized chunks.
10234                  */
10235                 cur_bytes = min(cur_bytes, last_alloc);
10236                 ret = btrfs_reserve_extent(root, cur_bytes, cur_bytes,
10237                                 min_size, 0, *alloc_hint, &ins, 1, 0);
10238                 if (ret) {
10239                         if (own_trans)
10240                                 btrfs_end_transaction(trans);
10241                         break;
10242                 }
10243                 btrfs_dec_block_group_reservations(fs_info, ins.objectid);
10244
10245                 last_alloc = ins.offset;
10246                 ret = insert_reserved_file_extent(trans, inode,
10247                                                   cur_offset, ins.objectid,
10248                                                   ins.offset, ins.offset,
10249                                                   ins.offset, 0, 0, 0,
10250                                                   BTRFS_FILE_EXTENT_PREALLOC);
10251                 if (ret) {
10252                         btrfs_free_reserved_extent(fs_info, ins.objectid,
10253                                                    ins.offset, 0);
10254                         btrfs_abort_transaction(trans, ret);
10255                         if (own_trans)
10256                                 btrfs_end_transaction(trans);
10257                         break;
10258                 }
10259
10260                 btrfs_drop_extent_cache(BTRFS_I(inode), cur_offset,
10261                                         cur_offset + ins.offset -1, 0);
10262
10263                 em = alloc_extent_map();
10264                 if (!em) {
10265                         set_bit(BTRFS_INODE_NEEDS_FULL_SYNC,
10266                                 &BTRFS_I(inode)->runtime_flags);
10267                         goto next;
10268                 }
10269
10270                 em->start = cur_offset;
10271                 em->orig_start = cur_offset;
10272                 em->len = ins.offset;
10273                 em->block_start = ins.objectid;
10274                 em->block_len = ins.offset;
10275                 em->orig_block_len = ins.offset;
10276                 em->ram_bytes = ins.offset;
10277                 em->bdev = fs_info->fs_devices->latest_bdev;
10278                 set_bit(EXTENT_FLAG_PREALLOC, &em->flags);
10279                 em->generation = trans->transid;
10280
10281                 while (1) {
10282                         write_lock(&em_tree->lock);
10283                         ret = add_extent_mapping(em_tree, em, 1);
10284                         write_unlock(&em_tree->lock);
10285                         if (ret != -EEXIST)
10286                                 break;
10287                         btrfs_drop_extent_cache(BTRFS_I(inode), cur_offset,
10288                                                 cur_offset + ins.offset - 1,
10289                                                 0);
10290                 }
10291                 free_extent_map(em);
10292 next:
10293                 num_bytes -= ins.offset;
10294                 cur_offset += ins.offset;
10295                 *alloc_hint = ins.objectid + ins.offset;
10296
10297                 inode_inc_iversion(inode);
10298                 inode->i_ctime = current_time(inode);
10299                 BTRFS_I(inode)->flags |= BTRFS_INODE_PREALLOC;
10300                 if (!(mode & FALLOC_FL_KEEP_SIZE) &&
10301                     (actual_len > inode->i_size) &&
10302                     (cur_offset > inode->i_size)) {
10303                         if (cur_offset > actual_len)
10304                                 i_size = actual_len;
10305                         else
10306                                 i_size = cur_offset;
10307                         i_size_write(inode, i_size);
10308                         btrfs_ordered_update_i_size(inode, i_size, NULL);
10309                 }
10310
10311                 ret = btrfs_update_inode(trans, root, inode);
10312
10313                 if (ret) {
10314                         btrfs_abort_transaction(trans, ret);
10315                         if (own_trans)
10316                                 btrfs_end_transaction(trans);
10317                         break;
10318                 }
10319
10320                 if (own_trans)
10321                         btrfs_end_transaction(trans);
10322         }
10323         if (cur_offset < end)
10324                 btrfs_free_reserved_data_space(inode, NULL, cur_offset,
10325                         end - cur_offset + 1);
10326         return ret;
10327 }
10328
10329 int btrfs_prealloc_file_range(struct inode *inode, int mode,
10330                               u64 start, u64 num_bytes, u64 min_size,
10331                               loff_t actual_len, u64 *alloc_hint)
10332 {
10333         return __btrfs_prealloc_file_range(inode, mode, start, num_bytes,
10334                                            min_size, actual_len, alloc_hint,
10335                                            NULL);
10336 }
10337
10338 int btrfs_prealloc_file_range_trans(struct inode *inode,
10339                                     struct btrfs_trans_handle *trans, int mode,
10340                                     u64 start, u64 num_bytes, u64 min_size,
10341                                     loff_t actual_len, u64 *alloc_hint)
10342 {
10343         return __btrfs_prealloc_file_range(inode, mode, start, num_bytes,
10344                                            min_size, actual_len, alloc_hint, trans);
10345 }
10346
10347 static int btrfs_set_page_dirty(struct page *page)
10348 {
10349         return __set_page_dirty_nobuffers(page);
10350 }
10351
10352 static int btrfs_permission(struct inode *inode, int mask)
10353 {
10354         struct btrfs_root *root = BTRFS_I(inode)->root;
10355         umode_t mode = inode->i_mode;
10356
10357         if (mask & MAY_WRITE &&
10358             (S_ISREG(mode) || S_ISDIR(mode) || S_ISLNK(mode))) {
10359                 if (btrfs_root_readonly(root))
10360                         return -EROFS;
10361                 if (BTRFS_I(inode)->flags & BTRFS_INODE_READONLY)
10362                         return -EACCES;
10363         }
10364         return generic_permission(inode, mask);
10365 }
10366
10367 static int btrfs_tmpfile(struct inode *dir, struct dentry *dentry, umode_t mode)
10368 {
10369         struct btrfs_fs_info *fs_info = btrfs_sb(dir->i_sb);
10370         struct btrfs_trans_handle *trans;
10371         struct btrfs_root *root = BTRFS_I(dir)->root;
10372         struct inode *inode = NULL;
10373         u64 objectid;
10374         u64 index;
10375         int ret = 0;
10376
10377         /*
10378          * 5 units required for adding orphan entry
10379          */
10380         trans = btrfs_start_transaction(root, 5);
10381         if (IS_ERR(trans))
10382                 return PTR_ERR(trans);
10383
10384         ret = btrfs_find_free_ino(root, &objectid);
10385         if (ret)
10386                 goto out;
10387
10388         inode = btrfs_new_inode(trans, root, dir, NULL, 0,
10389                         btrfs_ino(BTRFS_I(dir)), objectid, mode, &index);
10390         if (IS_ERR(inode)) {
10391                 ret = PTR_ERR(inode);
10392                 inode = NULL;
10393                 goto out;
10394         }
10395
10396         inode->i_fop = &btrfs_file_operations;
10397         inode->i_op = &btrfs_file_inode_operations;
10398
10399         inode->i_mapping->a_ops = &btrfs_aops;
10400         BTRFS_I(inode)->io_tree.ops = &btrfs_extent_io_ops;
10401
10402         ret = btrfs_init_inode_security(trans, inode, dir, NULL);
10403         if (ret)
10404                 goto out;
10405
10406         ret = btrfs_update_inode(trans, root, inode);
10407         if (ret)
10408                 goto out;
10409         ret = btrfs_orphan_add(trans, BTRFS_I(inode));
10410         if (ret)
10411                 goto out;
10412
10413         /*
10414          * We set number of links to 0 in btrfs_new_inode(), and here we set
10415          * it to 1 because d_tmpfile() will issue a warning if the count is 0,
10416          * through:
10417          *
10418          *    d_tmpfile() -> inode_dec_link_count() -> drop_nlink()
10419          */
10420         set_nlink(inode, 1);
10421         d_tmpfile(dentry, inode);
10422         unlock_new_inode(inode);
10423         mark_inode_dirty(inode);
10424 out:
10425         btrfs_end_transaction(trans);
10426         if (ret && inode)
10427                 discard_new_inode(inode);
10428         btrfs_btree_balance_dirty(fs_info);
10429         return ret;
10430 }
10431
10432 __attribute__((const))
10433 static int btrfs_readpage_io_failed_hook(struct page *page, int failed_mirror)
10434 {
10435         return -EAGAIN;
10436 }
10437
10438 static void btrfs_check_extent_io_range(void *private_data, const char *caller,
10439                                         u64 start, u64 end)
10440 {
10441         struct inode *inode = private_data;
10442         u64 isize;
10443
10444         isize = i_size_read(inode);
10445         if (end >= PAGE_SIZE && (end % 2) == 0 && end != isize - 1) {
10446                 btrfs_debug_rl(BTRFS_I(inode)->root->fs_info,
10447                     "%s: ino %llu isize %llu odd range [%llu,%llu]",
10448                         caller, btrfs_ino(BTRFS_I(inode)), isize, start, end);
10449         }
10450 }
10451
10452 void btrfs_set_range_writeback(struct extent_io_tree *tree, u64 start, u64 end)
10453 {
10454         struct inode *inode = tree->private_data;
10455         unsigned long index = start >> PAGE_SHIFT;
10456         unsigned long end_index = end >> PAGE_SHIFT;
10457         struct page *page;
10458
10459         while (index <= end_index) {
10460                 page = find_get_page(inode->i_mapping, index);
10461                 ASSERT(page); /* Pages should be in the extent_io_tree */
10462                 set_page_writeback(page);
10463                 put_page(page);
10464                 index++;
10465         }
10466 }
10467
10468 static const struct inode_operations btrfs_dir_inode_operations = {
10469         .getattr        = btrfs_getattr,
10470         .lookup         = btrfs_lookup,
10471         .create         = btrfs_create,
10472         .unlink         = btrfs_unlink,
10473         .link           = btrfs_link,
10474         .mkdir          = btrfs_mkdir,
10475         .rmdir          = btrfs_rmdir,
10476         .rename         = btrfs_rename2,
10477         .symlink        = btrfs_symlink,
10478         .setattr        = btrfs_setattr,
10479         .mknod          = btrfs_mknod,
10480         .listxattr      = btrfs_listxattr,
10481         .permission     = btrfs_permission,
10482         .get_acl        = btrfs_get_acl,
10483         .set_acl        = btrfs_set_acl,
10484         .update_time    = btrfs_update_time,
10485         .tmpfile        = btrfs_tmpfile,
10486 };
10487 static const struct inode_operations btrfs_dir_ro_inode_operations = {
10488         .lookup         = btrfs_lookup,
10489         .permission     = btrfs_permission,
10490         .update_time    = btrfs_update_time,
10491 };
10492
10493 static const struct file_operations btrfs_dir_file_operations = {
10494         .llseek         = generic_file_llseek,
10495         .read           = generic_read_dir,
10496         .iterate_shared = btrfs_real_readdir,
10497         .open           = btrfs_opendir,
10498         .unlocked_ioctl = btrfs_ioctl,
10499 #ifdef CONFIG_COMPAT
10500         .compat_ioctl   = btrfs_compat_ioctl,
10501 #endif
10502         .release        = btrfs_release_file,
10503         .fsync          = btrfs_sync_file,
10504 };
10505
10506 static const struct extent_io_ops btrfs_extent_io_ops = {
10507         /* mandatory callbacks */
10508         .submit_bio_hook = btrfs_submit_bio_hook,
10509         .readpage_end_io_hook = btrfs_readpage_end_io_hook,
10510         .readpage_io_failed_hook = btrfs_readpage_io_failed_hook,
10511
10512         /* optional callbacks */
10513         .fill_delalloc = run_delalloc_range,
10514         .writepage_end_io_hook = btrfs_writepage_end_io_hook,
10515         .writepage_start_hook = btrfs_writepage_start_hook,
10516         .set_bit_hook = btrfs_set_bit_hook,
10517         .clear_bit_hook = btrfs_clear_bit_hook,
10518         .merge_extent_hook = btrfs_merge_extent_hook,
10519         .split_extent_hook = btrfs_split_extent_hook,
10520         .check_extent_io_range = btrfs_check_extent_io_range,
10521 };
10522
10523 /*
10524  * btrfs doesn't support the bmap operation because swapfiles
10525  * use bmap to make a mapping of extents in the file.  They assume
10526  * these extents won't change over the life of the file and they
10527  * use the bmap result to do IO directly to the drive.
10528  *
10529  * the btrfs bmap call would return logical addresses that aren't
10530  * suitable for IO and they also will change frequently as COW
10531  * operations happen.  So, swapfile + btrfs == corruption.
10532  *
10533  * For now we're avoiding this by dropping bmap.
10534  */
10535 static const struct address_space_operations btrfs_aops = {
10536         .readpage       = btrfs_readpage,
10537         .writepage      = btrfs_writepage,
10538         .writepages     = btrfs_writepages,
10539         .readpages      = btrfs_readpages,
10540         .direct_IO      = btrfs_direct_IO,
10541         .invalidatepage = btrfs_invalidatepage,
10542         .releasepage    = btrfs_releasepage,
10543         .set_page_dirty = btrfs_set_page_dirty,
10544         .error_remove_page = generic_error_remove_page,
10545 };
10546
10547 static const struct inode_operations btrfs_file_inode_operations = {
10548         .getattr        = btrfs_getattr,
10549         .setattr        = btrfs_setattr,
10550         .listxattr      = btrfs_listxattr,
10551         .permission     = btrfs_permission,
10552         .fiemap         = btrfs_fiemap,
10553         .get_acl        = btrfs_get_acl,
10554         .set_acl        = btrfs_set_acl,
10555         .update_time    = btrfs_update_time,
10556 };
10557 static const struct inode_operations btrfs_special_inode_operations = {
10558         .getattr        = btrfs_getattr,
10559         .setattr        = btrfs_setattr,
10560         .permission     = btrfs_permission,
10561         .listxattr      = btrfs_listxattr,
10562         .get_acl        = btrfs_get_acl,
10563         .set_acl        = btrfs_set_acl,
10564         .update_time    = btrfs_update_time,
10565 };
10566 static const struct inode_operations btrfs_symlink_inode_operations = {
10567         .get_link       = page_get_link,
10568         .getattr        = btrfs_getattr,
10569         .setattr        = btrfs_setattr,
10570         .permission     = btrfs_permission,
10571         .listxattr      = btrfs_listxattr,
10572         .update_time    = btrfs_update_time,
10573 };
10574
10575 const struct dentry_operations btrfs_dentry_operations = {
10576         .d_delete       = btrfs_dentry_delete,
10577 };