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 = btrfs_lookup_dentry(dir, dentry);
5768
5769         if (inode == ERR_PTR(-ENOENT))
5770                 inode = NULL;
5771         return d_splice_alias(inode, dentry);
5772 }
5773
5774 unsigned char btrfs_filetype_table[] = {
5775         DT_UNKNOWN, DT_REG, DT_DIR, DT_CHR, DT_BLK, DT_FIFO, DT_SOCK, DT_LNK
5776 };
5777
5778 /*
5779  * All this infrastructure exists because dir_emit can fault, and we are holding
5780  * the tree lock when doing readdir.  For now just allocate a buffer and copy
5781  * our information into that, and then dir_emit from the buffer.  This is
5782  * similar to what NFS does, only we don't keep the buffer around in pagecache
5783  * because I'm afraid I'll mess that up.  Long term we need to make filldir do
5784  * copy_to_user_inatomic so we don't have to worry about page faulting under the
5785  * tree lock.
5786  */
5787 static int btrfs_opendir(struct inode *inode, struct file *file)
5788 {
5789         struct btrfs_file_private *private;
5790
5791         private = kzalloc(sizeof(struct btrfs_file_private), GFP_KERNEL);
5792         if (!private)
5793                 return -ENOMEM;
5794         private->filldir_buf = kzalloc(PAGE_SIZE, GFP_KERNEL);
5795         if (!private->filldir_buf) {
5796                 kfree(private);
5797                 return -ENOMEM;
5798         }
5799         file->private_data = private;
5800         return 0;
5801 }
5802
5803 struct dir_entry {
5804         u64 ino;
5805         u64 offset;
5806         unsigned type;
5807         int name_len;
5808 };
5809
5810 static int btrfs_filldir(void *addr, int entries, struct dir_context *ctx)
5811 {
5812         while (entries--) {
5813                 struct dir_entry *entry = addr;
5814                 char *name = (char *)(entry + 1);
5815
5816                 ctx->pos = get_unaligned(&entry->offset);
5817                 if (!dir_emit(ctx, name, get_unaligned(&entry->name_len),
5818                                          get_unaligned(&entry->ino),
5819                                          get_unaligned(&entry->type)))
5820                         return 1;
5821                 addr += sizeof(struct dir_entry) +
5822                         get_unaligned(&entry->name_len);
5823                 ctx->pos++;
5824         }
5825         return 0;
5826 }
5827
5828 static int btrfs_real_readdir(struct file *file, struct dir_context *ctx)
5829 {
5830         struct inode *inode = file_inode(file);
5831         struct btrfs_root *root = BTRFS_I(inode)->root;
5832         struct btrfs_file_private *private = file->private_data;
5833         struct btrfs_dir_item *di;
5834         struct btrfs_key key;
5835         struct btrfs_key found_key;
5836         struct btrfs_path *path;
5837         void *addr;
5838         struct list_head ins_list;
5839         struct list_head del_list;
5840         int ret;
5841         struct extent_buffer *leaf;
5842         int slot;
5843         char *name_ptr;
5844         int name_len;
5845         int entries = 0;
5846         int total_len = 0;
5847         bool put = false;
5848         struct btrfs_key location;
5849
5850         if (!dir_emit_dots(file, ctx))
5851                 return 0;
5852
5853         path = btrfs_alloc_path();
5854         if (!path)
5855                 return -ENOMEM;
5856
5857         addr = private->filldir_buf;
5858         path->reada = READA_FORWARD;
5859
5860         INIT_LIST_HEAD(&ins_list);
5861         INIT_LIST_HEAD(&del_list);
5862         put = btrfs_readdir_get_delayed_items(inode, &ins_list, &del_list);
5863
5864 again:
5865         key.type = BTRFS_DIR_INDEX_KEY;
5866         key.offset = ctx->pos;
5867         key.objectid = btrfs_ino(BTRFS_I(inode));
5868
5869         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
5870         if (ret < 0)
5871                 goto err;
5872
5873         while (1) {
5874                 struct dir_entry *entry;
5875
5876                 leaf = path->nodes[0];
5877                 slot = path->slots[0];
5878                 if (slot >= btrfs_header_nritems(leaf)) {
5879                         ret = btrfs_next_leaf(root, path);
5880                         if (ret < 0)
5881                                 goto err;
5882                         else if (ret > 0)
5883                                 break;
5884                         continue;
5885                 }
5886
5887                 btrfs_item_key_to_cpu(leaf, &found_key, slot);
5888
5889                 if (found_key.objectid != key.objectid)
5890                         break;
5891                 if (found_key.type != BTRFS_DIR_INDEX_KEY)
5892                         break;
5893                 if (found_key.offset < ctx->pos)
5894                         goto next;
5895                 if (btrfs_should_delete_dir_index(&del_list, found_key.offset))
5896                         goto next;
5897                 di = btrfs_item_ptr(leaf, slot, struct btrfs_dir_item);
5898                 name_len = btrfs_dir_name_len(leaf, di);
5899                 if ((total_len + sizeof(struct dir_entry) + name_len) >=
5900                     PAGE_SIZE) {
5901                         btrfs_release_path(path);
5902                         ret = btrfs_filldir(private->filldir_buf, entries, ctx);
5903                         if (ret)
5904                                 goto nopos;
5905                         addr = private->filldir_buf;
5906                         entries = 0;
5907                         total_len = 0;
5908                         goto again;
5909                 }
5910
5911                 entry = addr;
5912                 put_unaligned(name_len, &entry->name_len);
5913                 name_ptr = (char *)(entry + 1);
5914                 read_extent_buffer(leaf, name_ptr, (unsigned long)(di + 1),
5915                                    name_len);
5916                 put_unaligned(btrfs_filetype_table[btrfs_dir_type(leaf, di)],
5917                                 &entry->type);
5918                 btrfs_dir_item_key_to_cpu(leaf, di, &location);
5919                 put_unaligned(location.objectid, &entry->ino);
5920                 put_unaligned(found_key.offset, &entry->offset);
5921                 entries++;
5922                 addr += sizeof(struct dir_entry) + name_len;
5923                 total_len += sizeof(struct dir_entry) + name_len;
5924 next:
5925                 path->slots[0]++;
5926         }
5927         btrfs_release_path(path);
5928
5929         ret = btrfs_filldir(private->filldir_buf, entries, ctx);
5930         if (ret)
5931                 goto nopos;
5932
5933         ret = btrfs_readdir_delayed_dir_index(ctx, &ins_list);
5934         if (ret)
5935                 goto nopos;
5936
5937         /*
5938          * Stop new entries from being returned after we return the last
5939          * entry.
5940          *
5941          * New directory entries are assigned a strictly increasing
5942          * offset.  This means that new entries created during readdir
5943          * are *guaranteed* to be seen in the future by that readdir.
5944          * This has broken buggy programs which operate on names as
5945          * they're returned by readdir.  Until we re-use freed offsets
5946          * we have this hack to stop new entries from being returned
5947          * under the assumption that they'll never reach this huge
5948          * offset.
5949          *
5950          * This is being careful not to overflow 32bit loff_t unless the
5951          * last entry requires it because doing so has broken 32bit apps
5952          * in the past.
5953          */
5954         if (ctx->pos >= INT_MAX)
5955                 ctx->pos = LLONG_MAX;
5956         else
5957                 ctx->pos = INT_MAX;
5958 nopos:
5959         ret = 0;
5960 err:
5961         if (put)
5962                 btrfs_readdir_put_delayed_items(inode, &ins_list, &del_list);
5963         btrfs_free_path(path);
5964         return ret;
5965 }
5966
5967 /*
5968  * This is somewhat expensive, updating the tree every time the
5969  * inode changes.  But, it is most likely to find the inode in cache.
5970  * FIXME, needs more benchmarking...there are no reasons other than performance
5971  * to keep or drop this code.
5972  */
5973 static int btrfs_dirty_inode(struct inode *inode)
5974 {
5975         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
5976         struct btrfs_root *root = BTRFS_I(inode)->root;
5977         struct btrfs_trans_handle *trans;
5978         int ret;
5979
5980         if (test_bit(BTRFS_INODE_DUMMY, &BTRFS_I(inode)->runtime_flags))
5981                 return 0;
5982
5983         trans = btrfs_join_transaction(root);
5984         if (IS_ERR(trans))
5985                 return PTR_ERR(trans);
5986
5987         ret = btrfs_update_inode(trans, root, inode);
5988         if (ret && ret == -ENOSPC) {
5989                 /* whoops, lets try again with the full transaction */
5990                 btrfs_end_transaction(trans);
5991                 trans = btrfs_start_transaction(root, 1);
5992                 if (IS_ERR(trans))
5993                         return PTR_ERR(trans);
5994
5995                 ret = btrfs_update_inode(trans, root, inode);
5996         }
5997         btrfs_end_transaction(trans);
5998         if (BTRFS_I(inode)->delayed_node)
5999                 btrfs_balance_delayed_items(fs_info);
6000
6001         return ret;
6002 }
6003
6004 /*
6005  * This is a copy of file_update_time.  We need this so we can return error on
6006  * ENOSPC for updating the inode in the case of file write and mmap writes.
6007  */
6008 static int btrfs_update_time(struct inode *inode, struct timespec64 *now,
6009                              int flags)
6010 {
6011         struct btrfs_root *root = BTRFS_I(inode)->root;
6012         bool dirty = flags & ~S_VERSION;
6013
6014         if (btrfs_root_readonly(root))
6015                 return -EROFS;
6016
6017         if (flags & S_VERSION)
6018                 dirty |= inode_maybe_inc_iversion(inode, dirty);
6019         if (flags & S_CTIME)
6020                 inode->i_ctime = *now;
6021         if (flags & S_MTIME)
6022                 inode->i_mtime = *now;
6023         if (flags & S_ATIME)
6024                 inode->i_atime = *now;
6025         return dirty ? btrfs_dirty_inode(inode) : 0;
6026 }
6027
6028 /*
6029  * find the highest existing sequence number in a directory
6030  * and then set the in-memory index_cnt variable to reflect
6031  * free sequence numbers
6032  */
6033 static int btrfs_set_inode_index_count(struct btrfs_inode *inode)
6034 {
6035         struct btrfs_root *root = inode->root;
6036         struct btrfs_key key, found_key;
6037         struct btrfs_path *path;
6038         struct extent_buffer *leaf;
6039         int ret;
6040
6041         key.objectid = btrfs_ino(inode);
6042         key.type = BTRFS_DIR_INDEX_KEY;
6043         key.offset = (u64)-1;
6044
6045         path = btrfs_alloc_path();
6046         if (!path)
6047                 return -ENOMEM;
6048
6049         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
6050         if (ret < 0)
6051                 goto out;
6052         /* FIXME: we should be able to handle this */
6053         if (ret == 0)
6054                 goto out;
6055         ret = 0;
6056
6057         /*
6058          * MAGIC NUMBER EXPLANATION:
6059          * since we search a directory based on f_pos we have to start at 2
6060          * since '.' and '..' have f_pos of 0 and 1 respectively, so everybody
6061          * else has to start at 2
6062          */
6063         if (path->slots[0] == 0) {
6064                 inode->index_cnt = 2;
6065                 goto out;
6066         }
6067
6068         path->slots[0]--;
6069
6070         leaf = path->nodes[0];
6071         btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
6072
6073         if (found_key.objectid != btrfs_ino(inode) ||
6074             found_key.type != BTRFS_DIR_INDEX_KEY) {
6075                 inode->index_cnt = 2;
6076                 goto out;
6077         }
6078
6079         inode->index_cnt = found_key.offset + 1;
6080 out:
6081         btrfs_free_path(path);
6082         return ret;
6083 }
6084
6085 /*
6086  * helper to find a free sequence number in a given directory.  This current
6087  * code is very simple, later versions will do smarter things in the btree
6088  */
6089 int btrfs_set_inode_index(struct btrfs_inode *dir, u64 *index)
6090 {
6091         int ret = 0;
6092
6093         if (dir->index_cnt == (u64)-1) {
6094                 ret = btrfs_inode_delayed_dir_index_count(dir);
6095                 if (ret) {
6096                         ret = btrfs_set_inode_index_count(dir);
6097                         if (ret)
6098                                 return ret;
6099                 }
6100         }
6101
6102         *index = dir->index_cnt;
6103         dir->index_cnt++;
6104
6105         return ret;
6106 }
6107
6108 static int btrfs_insert_inode_locked(struct inode *inode)
6109 {
6110         struct btrfs_iget_args args;
6111         args.location = &BTRFS_I(inode)->location;
6112         args.root = BTRFS_I(inode)->root;
6113
6114         return insert_inode_locked4(inode,
6115                    btrfs_inode_hash(inode->i_ino, BTRFS_I(inode)->root),
6116                    btrfs_find_actor, &args);
6117 }
6118
6119 /*
6120  * Inherit flags from the parent inode.
6121  *
6122  * Currently only the compression flags and the cow flags are inherited.
6123  */
6124 static void btrfs_inherit_iflags(struct inode *inode, struct inode *dir)
6125 {
6126         unsigned int flags;
6127
6128         if (!dir)
6129                 return;
6130
6131         flags = BTRFS_I(dir)->flags;
6132
6133         if (flags & BTRFS_INODE_NOCOMPRESS) {
6134                 BTRFS_I(inode)->flags &= ~BTRFS_INODE_COMPRESS;
6135                 BTRFS_I(inode)->flags |= BTRFS_INODE_NOCOMPRESS;
6136         } else if (flags & BTRFS_INODE_COMPRESS) {
6137                 BTRFS_I(inode)->flags &= ~BTRFS_INODE_NOCOMPRESS;
6138                 BTRFS_I(inode)->flags |= BTRFS_INODE_COMPRESS;
6139         }
6140
6141         if (flags & BTRFS_INODE_NODATACOW) {
6142                 BTRFS_I(inode)->flags |= BTRFS_INODE_NODATACOW;
6143                 if (S_ISREG(inode->i_mode))
6144                         BTRFS_I(inode)->flags |= BTRFS_INODE_NODATASUM;
6145         }
6146
6147         btrfs_sync_inode_flags_to_i_flags(inode);
6148 }
6149
6150 static struct inode *btrfs_new_inode(struct btrfs_trans_handle *trans,
6151                                      struct btrfs_root *root,
6152                                      struct inode *dir,
6153                                      const char *name, int name_len,
6154                                      u64 ref_objectid, u64 objectid,
6155                                      umode_t mode, u64 *index)
6156 {
6157         struct btrfs_fs_info *fs_info = root->fs_info;
6158         struct inode *inode;
6159         struct btrfs_inode_item *inode_item;
6160         struct btrfs_key *location;
6161         struct btrfs_path *path;
6162         struct btrfs_inode_ref *ref;
6163         struct btrfs_key key[2];
6164         u32 sizes[2];
6165         int nitems = name ? 2 : 1;
6166         unsigned long ptr;
6167         int ret;
6168
6169         path = btrfs_alloc_path();
6170         if (!path)
6171                 return ERR_PTR(-ENOMEM);
6172
6173         inode = new_inode(fs_info->sb);
6174         if (!inode) {
6175                 btrfs_free_path(path);
6176                 return ERR_PTR(-ENOMEM);
6177         }
6178
6179         /*
6180          * O_TMPFILE, set link count to 0, so that after this point,
6181          * we fill in an inode item with the correct link count.
6182          */
6183         if (!name)
6184                 set_nlink(inode, 0);
6185
6186         /*
6187          * we have to initialize this early, so we can reclaim the inode
6188          * number if we fail afterwards in this function.
6189          */
6190         inode->i_ino = objectid;
6191
6192         if (dir && name) {
6193                 trace_btrfs_inode_request(dir);
6194
6195                 ret = btrfs_set_inode_index(BTRFS_I(dir), index);
6196                 if (ret) {
6197                         btrfs_free_path(path);
6198                         iput(inode);
6199                         return ERR_PTR(ret);
6200                 }
6201         } else if (dir) {
6202                 *index = 0;
6203         }
6204         /*
6205          * index_cnt is ignored for everything but a dir,
6206          * btrfs_set_inode_index_count has an explanation for the magic
6207          * number
6208          */
6209         BTRFS_I(inode)->index_cnt = 2;
6210         BTRFS_I(inode)->dir_index = *index;
6211         BTRFS_I(inode)->root = root;
6212         BTRFS_I(inode)->generation = trans->transid;
6213         inode->i_generation = BTRFS_I(inode)->generation;
6214
6215         /*
6216          * We could have gotten an inode number from somebody who was fsynced
6217          * and then removed in this same transaction, so let's just set full
6218          * sync since it will be a full sync anyway and this will blow away the
6219          * old info in the log.
6220          */
6221         set_bit(BTRFS_INODE_NEEDS_FULL_SYNC, &BTRFS_I(inode)->runtime_flags);
6222
6223         key[0].objectid = objectid;
6224         key[0].type = BTRFS_INODE_ITEM_KEY;
6225         key[0].offset = 0;
6226
6227         sizes[0] = sizeof(struct btrfs_inode_item);
6228
6229         if (name) {
6230                 /*
6231                  * Start new inodes with an inode_ref. This is slightly more
6232                  * efficient for small numbers of hard links since they will
6233                  * be packed into one item. Extended refs will kick in if we
6234                  * add more hard links than can fit in the ref item.
6235                  */
6236                 key[1].objectid = objectid;
6237                 key[1].type = BTRFS_INODE_REF_KEY;
6238                 key[1].offset = ref_objectid;
6239
6240                 sizes[1] = name_len + sizeof(*ref);
6241         }
6242
6243         location = &BTRFS_I(inode)->location;
6244         location->objectid = objectid;
6245         location->offset = 0;
6246         location->type = BTRFS_INODE_ITEM_KEY;
6247
6248         ret = btrfs_insert_inode_locked(inode);
6249         if (ret < 0) {
6250                 iput(inode);
6251                 goto fail;
6252         }
6253
6254         path->leave_spinning = 1;
6255         ret = btrfs_insert_empty_items(trans, root, path, key, sizes, nitems);
6256         if (ret != 0)
6257                 goto fail_unlock;
6258
6259         inode_init_owner(inode, dir, mode);
6260         inode_set_bytes(inode, 0);
6261
6262         inode->i_mtime = current_time(inode);
6263         inode->i_atime = inode->i_mtime;
6264         inode->i_ctime = inode->i_mtime;
6265         BTRFS_I(inode)->i_otime = inode->i_mtime;
6266
6267         inode_item = btrfs_item_ptr(path->nodes[0], path->slots[0],
6268                                   struct btrfs_inode_item);
6269         memzero_extent_buffer(path->nodes[0], (unsigned long)inode_item,
6270                              sizeof(*inode_item));
6271         fill_inode_item(trans, path->nodes[0], inode_item, inode);
6272
6273         if (name) {
6274                 ref = btrfs_item_ptr(path->nodes[0], path->slots[0] + 1,
6275                                      struct btrfs_inode_ref);
6276                 btrfs_set_inode_ref_name_len(path->nodes[0], ref, name_len);
6277                 btrfs_set_inode_ref_index(path->nodes[0], ref, *index);
6278                 ptr = (unsigned long)(ref + 1);
6279                 write_extent_buffer(path->nodes[0], name, ptr, name_len);
6280         }
6281
6282         btrfs_mark_buffer_dirty(path->nodes[0]);
6283         btrfs_free_path(path);
6284
6285         btrfs_inherit_iflags(inode, dir);
6286
6287         if (S_ISREG(mode)) {
6288                 if (btrfs_test_opt(fs_info, NODATASUM))
6289                         BTRFS_I(inode)->flags |= BTRFS_INODE_NODATASUM;
6290                 if (btrfs_test_opt(fs_info, NODATACOW))
6291                         BTRFS_I(inode)->flags |= BTRFS_INODE_NODATACOW |
6292                                 BTRFS_INODE_NODATASUM;
6293         }
6294
6295         inode_tree_add(inode);
6296
6297         trace_btrfs_inode_new(inode);
6298         btrfs_set_inode_last_trans(trans, inode);
6299
6300         btrfs_update_root_times(trans, root);
6301
6302         ret = btrfs_inode_inherit_props(trans, inode, dir);
6303         if (ret)
6304                 btrfs_err(fs_info,
6305                           "error inheriting props for ino %llu (root %llu): %d",
6306                         btrfs_ino(BTRFS_I(inode)), root->root_key.objectid, ret);
6307
6308         return inode;
6309
6310 fail_unlock:
6311         discard_new_inode(inode);
6312 fail:
6313         if (dir && name)
6314                 BTRFS_I(dir)->index_cnt--;
6315         btrfs_free_path(path);
6316         return ERR_PTR(ret);
6317 }
6318
6319 static inline u8 btrfs_inode_type(struct inode *inode)
6320 {
6321         return btrfs_type_by_mode[(inode->i_mode & S_IFMT) >> S_SHIFT];
6322 }
6323
6324 /*
6325  * utility function to add 'inode' into 'parent_inode' with
6326  * a give name and a given sequence number.
6327  * if 'add_backref' is true, also insert a backref from the
6328  * inode to the parent directory.
6329  */
6330 int btrfs_add_link(struct btrfs_trans_handle *trans,
6331                    struct btrfs_inode *parent_inode, struct btrfs_inode *inode,
6332                    const char *name, int name_len, int add_backref, u64 index)
6333 {
6334         int ret = 0;
6335         struct btrfs_key key;
6336         struct btrfs_root *root = parent_inode->root;
6337         u64 ino = btrfs_ino(inode);
6338         u64 parent_ino = btrfs_ino(parent_inode);
6339
6340         if (unlikely(ino == BTRFS_FIRST_FREE_OBJECTID)) {
6341                 memcpy(&key, &inode->root->root_key, sizeof(key));
6342         } else {
6343                 key.objectid = ino;
6344                 key.type = BTRFS_INODE_ITEM_KEY;
6345                 key.offset = 0;
6346         }
6347
6348         if (unlikely(ino == BTRFS_FIRST_FREE_OBJECTID)) {
6349                 ret = btrfs_add_root_ref(trans, key.objectid,
6350                                          root->root_key.objectid, parent_ino,
6351                                          index, name, name_len);
6352         } else if (add_backref) {
6353                 ret = btrfs_insert_inode_ref(trans, root, name, name_len, ino,
6354                                              parent_ino, index);
6355         }
6356
6357         /* Nothing to clean up yet */
6358         if (ret)
6359                 return ret;
6360
6361         ret = btrfs_insert_dir_item(trans, name, name_len, parent_inode, &key,
6362                                     btrfs_inode_type(&inode->vfs_inode), index);
6363         if (ret == -EEXIST || ret == -EOVERFLOW)
6364                 goto fail_dir_item;
6365         else if (ret) {
6366                 btrfs_abort_transaction(trans, ret);
6367                 return ret;
6368         }
6369
6370         btrfs_i_size_write(parent_inode, parent_inode->vfs_inode.i_size +
6371                            name_len * 2);
6372         inode_inc_iversion(&parent_inode->vfs_inode);
6373         parent_inode->vfs_inode.i_mtime = parent_inode->vfs_inode.i_ctime =
6374                 current_time(&parent_inode->vfs_inode);
6375         ret = btrfs_update_inode(trans, root, &parent_inode->vfs_inode);
6376         if (ret)
6377                 btrfs_abort_transaction(trans, ret);
6378         return ret;
6379
6380 fail_dir_item:
6381         if (unlikely(ino == BTRFS_FIRST_FREE_OBJECTID)) {
6382                 u64 local_index;
6383                 int err;
6384                 err = btrfs_del_root_ref(trans, key.objectid,
6385                                          root->root_key.objectid, parent_ino,
6386                                          &local_index, name, name_len);
6387
6388         } else if (add_backref) {
6389                 u64 local_index;
6390                 int err;
6391
6392                 err = btrfs_del_inode_ref(trans, root, name, name_len,
6393                                           ino, parent_ino, &local_index);
6394         }
6395         return ret;
6396 }
6397
6398 static int btrfs_add_nondir(struct btrfs_trans_handle *trans,
6399                             struct btrfs_inode *dir, struct dentry *dentry,
6400                             struct btrfs_inode *inode, int backref, u64 index)
6401 {
6402         int err = btrfs_add_link(trans, dir, inode,
6403                                  dentry->d_name.name, dentry->d_name.len,
6404                                  backref, index);
6405         if (err > 0)
6406                 err = -EEXIST;
6407         return err;
6408 }
6409
6410 static int btrfs_mknod(struct inode *dir, struct dentry *dentry,
6411                         umode_t mode, dev_t rdev)
6412 {
6413         struct btrfs_fs_info *fs_info = btrfs_sb(dir->i_sb);
6414         struct btrfs_trans_handle *trans;
6415         struct btrfs_root *root = BTRFS_I(dir)->root;
6416         struct inode *inode = NULL;
6417         int err;
6418         u64 objectid;
6419         u64 index = 0;
6420
6421         /*
6422          * 2 for inode item and ref
6423          * 2 for dir items
6424          * 1 for xattr if selinux is on
6425          */
6426         trans = btrfs_start_transaction(root, 5);
6427         if (IS_ERR(trans))
6428                 return PTR_ERR(trans);
6429
6430         err = btrfs_find_free_ino(root, &objectid);
6431         if (err)
6432                 goto out_unlock;
6433
6434         inode = btrfs_new_inode(trans, root, dir, dentry->d_name.name,
6435                         dentry->d_name.len, btrfs_ino(BTRFS_I(dir)), objectid,
6436                         mode, &index);
6437         if (IS_ERR(inode)) {
6438                 err = PTR_ERR(inode);
6439                 inode = NULL;
6440                 goto out_unlock;
6441         }
6442
6443         /*
6444         * If the active LSM wants to access the inode during
6445         * d_instantiate it needs these. Smack checks to see
6446         * if the filesystem supports xattrs by looking at the
6447         * ops vector.
6448         */
6449         inode->i_op = &btrfs_special_inode_operations;
6450         init_special_inode(inode, inode->i_mode, rdev);
6451
6452         err = btrfs_init_inode_security(trans, inode, dir, &dentry->d_name);
6453         if (err)
6454                 goto out_unlock;
6455
6456         err = btrfs_add_nondir(trans, BTRFS_I(dir), dentry, BTRFS_I(inode),
6457                         0, index);
6458         if (err)
6459                 goto out_unlock;
6460
6461         btrfs_update_inode(trans, root, inode);
6462         d_instantiate_new(dentry, inode);
6463
6464 out_unlock:
6465         btrfs_end_transaction(trans);
6466         btrfs_btree_balance_dirty(fs_info);
6467         if (err && inode) {
6468                 inode_dec_link_count(inode);
6469                 discard_new_inode(inode);
6470         }
6471         return err;
6472 }
6473
6474 static int btrfs_create(struct inode *dir, struct dentry *dentry,
6475                         umode_t mode, bool excl)
6476 {
6477         struct btrfs_fs_info *fs_info = btrfs_sb(dir->i_sb);
6478         struct btrfs_trans_handle *trans;
6479         struct btrfs_root *root = BTRFS_I(dir)->root;
6480         struct inode *inode = NULL;
6481         int err;
6482         u64 objectid;
6483         u64 index = 0;
6484
6485         /*
6486          * 2 for inode item and ref
6487          * 2 for dir items
6488          * 1 for xattr if selinux is on
6489          */
6490         trans = btrfs_start_transaction(root, 5);
6491         if (IS_ERR(trans))
6492                 return PTR_ERR(trans);
6493
6494         err = btrfs_find_free_ino(root, &objectid);
6495         if (err)
6496                 goto out_unlock;
6497
6498         inode = btrfs_new_inode(trans, root, dir, dentry->d_name.name,
6499                         dentry->d_name.len, btrfs_ino(BTRFS_I(dir)), objectid,
6500                         mode, &index);
6501         if (IS_ERR(inode)) {
6502                 err = PTR_ERR(inode);
6503                 inode = NULL;
6504                 goto out_unlock;
6505         }
6506         /*
6507         * If the active LSM wants to access the inode during
6508         * d_instantiate it needs these. Smack checks to see
6509         * if the filesystem supports xattrs by looking at the
6510         * ops vector.
6511         */
6512         inode->i_fop = &btrfs_file_operations;
6513         inode->i_op = &btrfs_file_inode_operations;
6514         inode->i_mapping->a_ops = &btrfs_aops;
6515
6516         err = btrfs_init_inode_security(trans, inode, dir, &dentry->d_name);
6517         if (err)
6518                 goto out_unlock;
6519
6520         err = btrfs_update_inode(trans, root, inode);
6521         if (err)
6522                 goto out_unlock;
6523
6524         err = btrfs_add_nondir(trans, BTRFS_I(dir), dentry, BTRFS_I(inode),
6525                         0, index);
6526         if (err)
6527                 goto out_unlock;
6528
6529         BTRFS_I(inode)->io_tree.ops = &btrfs_extent_io_ops;
6530         d_instantiate_new(dentry, inode);
6531
6532 out_unlock:
6533         btrfs_end_transaction(trans);
6534         if (err && inode) {
6535                 inode_dec_link_count(inode);
6536                 discard_new_inode(inode);
6537         }
6538         btrfs_btree_balance_dirty(fs_info);
6539         return err;
6540 }
6541
6542 static int btrfs_link(struct dentry *old_dentry, struct inode *dir,
6543                       struct dentry *dentry)
6544 {
6545         struct btrfs_trans_handle *trans = NULL;
6546         struct btrfs_root *root = BTRFS_I(dir)->root;
6547         struct inode *inode = d_inode(old_dentry);
6548         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
6549         u64 index;
6550         int err;
6551         int drop_inode = 0;
6552
6553         /* do not allow sys_link's with other subvols of the same device */
6554         if (root->root_key.objectid != BTRFS_I(inode)->root->root_key.objectid)
6555                 return -EXDEV;
6556
6557         if (inode->i_nlink >= BTRFS_LINK_MAX)
6558                 return -EMLINK;
6559
6560         err = btrfs_set_inode_index(BTRFS_I(dir), &index);
6561         if (err)
6562                 goto fail;
6563
6564         /*
6565          * 2 items for inode and inode ref
6566          * 2 items for dir items
6567          * 1 item for parent inode
6568          * 1 item for orphan item deletion if O_TMPFILE
6569          */
6570         trans = btrfs_start_transaction(root, inode->i_nlink ? 5 : 6);
6571         if (IS_ERR(trans)) {
6572                 err = PTR_ERR(trans);
6573                 trans = NULL;
6574                 goto fail;
6575         }
6576
6577         /* There are several dir indexes for this inode, clear the cache. */
6578         BTRFS_I(inode)->dir_index = 0ULL;
6579         inc_nlink(inode);
6580         inode_inc_iversion(inode);
6581         inode->i_ctime = current_time(inode);
6582         ihold(inode);
6583         set_bit(BTRFS_INODE_COPY_EVERYTHING, &BTRFS_I(inode)->runtime_flags);
6584
6585         err = btrfs_add_nondir(trans, BTRFS_I(dir), dentry, BTRFS_I(inode),
6586                         1, index);
6587
6588         if (err) {
6589                 drop_inode = 1;
6590         } else {
6591                 struct dentry *parent = dentry->d_parent;
6592                 int ret;
6593
6594                 err = btrfs_update_inode(trans, root, inode);
6595                 if (err)
6596                         goto fail;
6597                 if (inode->i_nlink == 1) {
6598                         /*
6599                          * If new hard link count is 1, it's a file created
6600                          * with open(2) O_TMPFILE flag.
6601                          */
6602                         err = btrfs_orphan_del(trans, BTRFS_I(inode));
6603                         if (err)
6604                                 goto fail;
6605                 }
6606                 d_instantiate(dentry, inode);
6607                 ret = btrfs_log_new_name(trans, BTRFS_I(inode), NULL, parent,
6608                                          true, NULL);
6609                 if (ret == BTRFS_NEED_TRANS_COMMIT) {
6610                         err = btrfs_commit_transaction(trans);
6611                         trans = NULL;
6612                 }
6613         }
6614
6615 fail:
6616         if (trans)
6617                 btrfs_end_transaction(trans);
6618         if (drop_inode) {
6619                 inode_dec_link_count(inode);
6620                 iput(inode);
6621         }
6622         btrfs_btree_balance_dirty(fs_info);
6623         return err;
6624 }
6625
6626 static int btrfs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
6627 {
6628         struct btrfs_fs_info *fs_info = btrfs_sb(dir->i_sb);
6629         struct inode *inode = NULL;
6630         struct btrfs_trans_handle *trans;
6631         struct btrfs_root *root = BTRFS_I(dir)->root;
6632         int err = 0;
6633         int drop_on_err = 0;
6634         u64 objectid = 0;
6635         u64 index = 0;
6636
6637         /*
6638          * 2 items for inode and ref
6639          * 2 items for dir items
6640          * 1 for xattr if selinux is on
6641          */
6642         trans = btrfs_start_transaction(root, 5);
6643         if (IS_ERR(trans))
6644                 return PTR_ERR(trans);
6645
6646         err = btrfs_find_free_ino(root, &objectid);
6647         if (err)
6648                 goto out_fail;
6649
6650         inode = btrfs_new_inode(trans, root, dir, dentry->d_name.name,
6651                         dentry->d_name.len, btrfs_ino(BTRFS_I(dir)), objectid,
6652                         S_IFDIR | mode, &index);
6653         if (IS_ERR(inode)) {
6654                 err = PTR_ERR(inode);
6655                 inode = NULL;
6656                 goto out_fail;
6657         }
6658
6659         drop_on_err = 1;
6660         /* these must be set before we unlock the inode */
6661         inode->i_op = &btrfs_dir_inode_operations;
6662         inode->i_fop = &btrfs_dir_file_operations;
6663
6664         err = btrfs_init_inode_security(trans, inode, dir, &dentry->d_name);
6665         if (err)
6666                 goto out_fail;
6667
6668         btrfs_i_size_write(BTRFS_I(inode), 0);
6669         err = btrfs_update_inode(trans, root, inode);
6670         if (err)
6671                 goto out_fail;
6672
6673         err = btrfs_add_link(trans, BTRFS_I(dir), BTRFS_I(inode),
6674                         dentry->d_name.name,
6675                         dentry->d_name.len, 0, index);
6676         if (err)
6677                 goto out_fail;
6678
6679         d_instantiate_new(dentry, inode);
6680         drop_on_err = 0;
6681
6682 out_fail:
6683         btrfs_end_transaction(trans);
6684         if (err && inode) {
6685                 inode_dec_link_count(inode);
6686                 discard_new_inode(inode);
6687         }
6688         btrfs_btree_balance_dirty(fs_info);
6689         return err;
6690 }
6691
6692 static noinline int uncompress_inline(struct btrfs_path *path,
6693                                       struct page *page,
6694                                       size_t pg_offset, u64 extent_offset,
6695                                       struct btrfs_file_extent_item *item)
6696 {
6697         int ret;
6698         struct extent_buffer *leaf = path->nodes[0];
6699         char *tmp;
6700         size_t max_size;
6701         unsigned long inline_size;
6702         unsigned long ptr;
6703         int compress_type;
6704
6705         WARN_ON(pg_offset != 0);
6706         compress_type = btrfs_file_extent_compression(leaf, item);
6707         max_size = btrfs_file_extent_ram_bytes(leaf, item);
6708         inline_size = btrfs_file_extent_inline_item_len(leaf,
6709                                         btrfs_item_nr(path->slots[0]));
6710         tmp = kmalloc(inline_size, GFP_NOFS);
6711         if (!tmp)
6712                 return -ENOMEM;
6713         ptr = btrfs_file_extent_inline_start(item);
6714
6715         read_extent_buffer(leaf, tmp, ptr, inline_size);
6716
6717         max_size = min_t(unsigned long, PAGE_SIZE, max_size);
6718         ret = btrfs_decompress(compress_type, tmp, page,
6719                                extent_offset, inline_size, max_size);
6720
6721         /*
6722          * decompression code contains a memset to fill in any space between the end
6723          * of the uncompressed data and the end of max_size in case the decompressed
6724          * data ends up shorter than ram_bytes.  That doesn't cover the hole between
6725          * the end of an inline extent and the beginning of the next block, so we
6726          * cover that region here.
6727          */
6728
6729         if (max_size + pg_offset < PAGE_SIZE) {
6730                 char *map = kmap(page);
6731                 memset(map + pg_offset + max_size, 0, PAGE_SIZE - max_size - pg_offset);
6732                 kunmap(page);
6733         }
6734         kfree(tmp);
6735         return ret;
6736 }
6737
6738 /*
6739  * a bit scary, this does extent mapping from logical file offset to the disk.
6740  * the ugly parts come from merging extents from the disk with the in-ram
6741  * representation.  This gets more complex because of the data=ordered code,
6742  * where the in-ram extents might be locked pending data=ordered completion.
6743  *
6744  * This also copies inline extents directly into the page.
6745  */
6746 struct extent_map *btrfs_get_extent(struct btrfs_inode *inode,
6747                                     struct page *page,
6748                                     size_t pg_offset, u64 start, u64 len,
6749                                     int create)
6750 {
6751         struct btrfs_fs_info *fs_info = inode->root->fs_info;
6752         int ret;
6753         int err = 0;
6754         u64 extent_start = 0;
6755         u64 extent_end = 0;
6756         u64 objectid = btrfs_ino(inode);
6757         u32 found_type;
6758         struct btrfs_path *path = NULL;
6759         struct btrfs_root *root = inode->root;
6760         struct btrfs_file_extent_item *item;
6761         struct extent_buffer *leaf;
6762         struct btrfs_key found_key;
6763         struct extent_map *em = NULL;
6764         struct extent_map_tree *em_tree = &inode->extent_tree;
6765         struct extent_io_tree *io_tree = &inode->io_tree;
6766         const bool new_inline = !page || create;
6767
6768         read_lock(&em_tree->lock);
6769         em = lookup_extent_mapping(em_tree, start, len);
6770         if (em)
6771                 em->bdev = fs_info->fs_devices->latest_bdev;
6772         read_unlock(&em_tree->lock);
6773
6774         if (em) {
6775                 if (em->start > start || em->start + em->len <= start)
6776                         free_extent_map(em);
6777                 else if (em->block_start == EXTENT_MAP_INLINE && page)
6778                         free_extent_map(em);
6779                 else
6780                         goto out;
6781         }
6782         em = alloc_extent_map();
6783         if (!em) {
6784                 err = -ENOMEM;
6785                 goto out;
6786         }
6787         em->bdev = fs_info->fs_devices->latest_bdev;
6788         em->start = EXTENT_MAP_HOLE;
6789         em->orig_start = EXTENT_MAP_HOLE;
6790         em->len = (u64)-1;
6791         em->block_len = (u64)-1;
6792
6793         path = btrfs_alloc_path();
6794         if (!path) {
6795                 err = -ENOMEM;
6796                 goto out;
6797         }
6798
6799         /* Chances are we'll be called again, so go ahead and do readahead */
6800         path->reada = READA_FORWARD;
6801
6802         /*
6803          * Unless we're going to uncompress the inline extent, no sleep would
6804          * happen.
6805          */
6806         path->leave_spinning = 1;
6807
6808         ret = btrfs_lookup_file_extent(NULL, root, path, objectid, start, 0);
6809         if (ret < 0) {
6810                 err = ret;
6811                 goto out;
6812         }
6813
6814         if (ret != 0) {
6815                 if (path->slots[0] == 0)
6816                         goto not_found;
6817                 path->slots[0]--;
6818         }
6819
6820         leaf = path->nodes[0];
6821         item = btrfs_item_ptr(leaf, path->slots[0],
6822                               struct btrfs_file_extent_item);
6823         /* are we inside the extent that was found? */
6824         btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
6825         found_type = found_key.type;
6826         if (found_key.objectid != objectid ||
6827             found_type != BTRFS_EXTENT_DATA_KEY) {
6828                 /*
6829                  * If we backup past the first extent we want to move forward
6830                  * and see if there is an extent in front of us, otherwise we'll
6831                  * say there is a hole for our whole search range which can
6832                  * cause problems.
6833                  */
6834                 extent_end = start;
6835                 goto next;
6836         }
6837
6838         found_type = btrfs_file_extent_type(leaf, item);
6839         extent_start = found_key.offset;
6840         if (found_type == BTRFS_FILE_EXTENT_REG ||
6841             found_type == BTRFS_FILE_EXTENT_PREALLOC) {
6842                 extent_end = extent_start +
6843                        btrfs_file_extent_num_bytes(leaf, item);
6844
6845                 trace_btrfs_get_extent_show_fi_regular(inode, leaf, item,
6846                                                        extent_start);
6847         } else if (found_type == BTRFS_FILE_EXTENT_INLINE) {
6848                 size_t size;
6849
6850                 size = btrfs_file_extent_ram_bytes(leaf, item);
6851                 extent_end = ALIGN(extent_start + size,
6852                                    fs_info->sectorsize);
6853
6854                 trace_btrfs_get_extent_show_fi_inline(inode, leaf, item,
6855                                                       path->slots[0],
6856                                                       extent_start);
6857         }
6858 next:
6859         if (start >= extent_end) {
6860                 path->slots[0]++;
6861                 if (path->slots[0] >= btrfs_header_nritems(leaf)) {
6862                         ret = btrfs_next_leaf(root, path);
6863                         if (ret < 0) {
6864                                 err = ret;
6865                                 goto out;
6866                         }
6867                         if (ret > 0)
6868                                 goto not_found;
6869                         leaf = path->nodes[0];
6870                 }
6871                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
6872                 if (found_key.objectid != objectid ||
6873                     found_key.type != BTRFS_EXTENT_DATA_KEY)
6874                         goto not_found;
6875                 if (start + len <= found_key.offset)
6876                         goto not_found;
6877                 if (start > found_key.offset)
6878                         goto next;
6879                 em->start = start;
6880                 em->orig_start = start;
6881                 em->len = found_key.offset - start;
6882                 goto not_found_em;
6883         }
6884
6885         btrfs_extent_item_to_extent_map(inode, path, item,
6886                         new_inline, em);
6887
6888         if (found_type == BTRFS_FILE_EXTENT_REG ||
6889             found_type == BTRFS_FILE_EXTENT_PREALLOC) {
6890                 goto insert;
6891         } else if (found_type == BTRFS_FILE_EXTENT_INLINE) {
6892                 unsigned long ptr;
6893                 char *map;
6894                 size_t size;
6895                 size_t extent_offset;
6896                 size_t copy_size;
6897
6898                 if (new_inline)
6899                         goto out;
6900
6901                 size = btrfs_file_extent_ram_bytes(leaf, item);
6902                 extent_offset = page_offset(page) + pg_offset - extent_start;
6903                 copy_size = min_t(u64, PAGE_SIZE - pg_offset,
6904                                   size - extent_offset);
6905                 em->start = extent_start + extent_offset;
6906                 em->len = ALIGN(copy_size, fs_info->sectorsize);
6907                 em->orig_block_len = em->len;
6908                 em->orig_start = em->start;
6909                 ptr = btrfs_file_extent_inline_start(item) + extent_offset;
6910
6911                 btrfs_set_path_blocking(path);
6912                 if (!PageUptodate(page)) {
6913                         if (btrfs_file_extent_compression(leaf, item) !=
6914                             BTRFS_COMPRESS_NONE) {
6915                                 ret = uncompress_inline(path, page, pg_offset,
6916                                                         extent_offset, item);
6917                                 if (ret) {
6918                                         err = ret;
6919                                         goto out;
6920                                 }
6921                         } else {
6922                                 map = kmap(page);
6923                                 read_extent_buffer(leaf, map + pg_offset, ptr,
6924                                                    copy_size);
6925                                 if (pg_offset + copy_size < PAGE_SIZE) {
6926                                         memset(map + pg_offset + copy_size, 0,
6927                                                PAGE_SIZE - pg_offset -
6928                                                copy_size);
6929                                 }
6930                                 kunmap(page);
6931                         }
6932                         flush_dcache_page(page);
6933                 }
6934                 set_extent_uptodate(io_tree, em->start,
6935                                     extent_map_end(em) - 1, NULL, GFP_NOFS);
6936                 goto insert;
6937         }
6938 not_found:
6939         em->start = start;
6940         em->orig_start = start;
6941         em->len = len;
6942 not_found_em:
6943         em->block_start = EXTENT_MAP_HOLE;
6944 insert:
6945         btrfs_release_path(path);
6946         if (em->start > start || extent_map_end(em) <= start) {
6947                 btrfs_err(fs_info,
6948                           "bad extent! em: [%llu %llu] passed [%llu %llu]",
6949                           em->start, em->len, start, len);
6950                 err = -EIO;
6951                 goto out;
6952         }
6953
6954         err = 0;
6955         write_lock(&em_tree->lock);
6956         err = btrfs_add_extent_mapping(fs_info, em_tree, &em, start, len);
6957         write_unlock(&em_tree->lock);
6958 out:
6959         btrfs_free_path(path);
6960
6961         trace_btrfs_get_extent(root, inode, em);
6962
6963         if (err) {
6964                 free_extent_map(em);
6965                 return ERR_PTR(err);
6966         }
6967         BUG_ON(!em); /* Error is always set */
6968         return em;
6969 }
6970
6971 struct extent_map *btrfs_get_extent_fiemap(struct btrfs_inode *inode,
6972                 struct page *page,
6973                 size_t pg_offset, u64 start, u64 len,
6974                 int create)
6975 {
6976         struct extent_map *em;
6977         struct extent_map *hole_em = NULL;
6978         u64 range_start = start;
6979         u64 end;
6980         u64 found;
6981         u64 found_end;
6982         int err = 0;
6983
6984         em = btrfs_get_extent(inode, page, pg_offset, start, len, create);
6985         if (IS_ERR(em))
6986                 return em;
6987         /*
6988          * If our em maps to:
6989          * - a hole or
6990          * - a pre-alloc extent,
6991          * there might actually be delalloc bytes behind it.
6992          */
6993         if (em->block_start != EXTENT_MAP_HOLE &&
6994             !test_bit(EXTENT_FLAG_PREALLOC, &em->flags))
6995                 return em;
6996         else
6997                 hole_em = em;
6998
6999         /* check to see if we've wrapped (len == -1 or similar) */
7000         end = start + len;
7001         if (end < start)
7002                 end = (u64)-1;
7003         else
7004                 end -= 1;
7005
7006         em = NULL;
7007
7008         /* ok, we didn't find anything, lets look for delalloc */
7009         found = count_range_bits(&inode->io_tree, &range_start,
7010                                  end, len, EXTENT_DELALLOC, 1);
7011         found_end = range_start + found;
7012         if (found_end < range_start)
7013                 found_end = (u64)-1;
7014
7015         /*
7016          * we didn't find anything useful, return
7017          * the original results from get_extent()
7018          */
7019         if (range_start > end || found_end <= start) {
7020                 em = hole_em;
7021                 hole_em = NULL;
7022                 goto out;
7023         }
7024
7025         /* adjust the range_start to make sure it doesn't
7026          * go backwards from the start they passed in
7027          */
7028         range_start = max(start, range_start);
7029         found = found_end - range_start;
7030
7031         if (found > 0) {
7032                 u64 hole_start = start;
7033                 u64 hole_len = len;
7034
7035                 em = alloc_extent_map();
7036                 if (!em) {
7037                         err = -ENOMEM;
7038                         goto out;
7039                 }
7040                 /*
7041                  * when btrfs_get_extent can't find anything it
7042                  * returns one huge hole
7043                  *
7044                  * make sure what it found really fits our range, and
7045                  * adjust to make sure it is based on the start from
7046                  * the caller
7047                  */
7048                 if (hole_em) {
7049                         u64 calc_end = extent_map_end(hole_em);
7050
7051                         if (calc_end <= start || (hole_em->start > end)) {
7052                                 free_extent_map(hole_em);
7053                                 hole_em = NULL;
7054                         } else {
7055                                 hole_start = max(hole_em->start, start);
7056                                 hole_len = calc_end - hole_start;
7057                         }
7058                 }
7059                 em->bdev = NULL;
7060                 if (hole_em && range_start > hole_start) {
7061                         /* our hole starts before our delalloc, so we
7062                          * have to return just the parts of the hole
7063                          * that go until  the delalloc starts
7064                          */
7065                         em->len = min(hole_len,
7066                                       range_start - hole_start);
7067                         em->start = hole_start;
7068                         em->orig_start = hole_start;
7069                         /*
7070                          * don't adjust block start at all,
7071                          * it is fixed at EXTENT_MAP_HOLE
7072                          */
7073                         em->block_start = hole_em->block_start;
7074                         em->block_len = hole_len;
7075                         if (test_bit(EXTENT_FLAG_PREALLOC, &hole_em->flags))
7076                                 set_bit(EXTENT_FLAG_PREALLOC, &em->flags);
7077                 } else {
7078                         em->start = range_start;
7079                         em->len = found;
7080                         em->orig_start = range_start;
7081                         em->block_start = EXTENT_MAP_DELALLOC;
7082                         em->block_len = found;
7083                 }
7084         } else {
7085                 return hole_em;
7086         }
7087 out:
7088
7089         free_extent_map(hole_em);
7090         if (err) {
7091                 free_extent_map(em);
7092                 return ERR_PTR(err);
7093         }
7094         return em;
7095 }
7096
7097 static struct extent_map *btrfs_create_dio_extent(struct inode *inode,
7098                                                   const u64 start,
7099                                                   const u64 len,
7100                                                   const u64 orig_start,
7101                                                   const u64 block_start,
7102                                                   const u64 block_len,
7103                                                   const u64 orig_block_len,
7104                                                   const u64 ram_bytes,
7105                                                   const int type)
7106 {
7107         struct extent_map *em = NULL;
7108         int ret;
7109
7110         if (type != BTRFS_ORDERED_NOCOW) {
7111                 em = create_io_em(inode, start, len, orig_start,
7112                                   block_start, block_len, orig_block_len,
7113                                   ram_bytes,
7114                                   BTRFS_COMPRESS_NONE, /* compress_type */
7115                                   type);
7116                 if (IS_ERR(em))
7117                         goto out;
7118         }
7119         ret = btrfs_add_ordered_extent_dio(inode, start, block_start,
7120                                            len, block_len, type);
7121         if (ret) {
7122                 if (em) {
7123                         free_extent_map(em);
7124                         btrfs_drop_extent_cache(BTRFS_I(inode), start,
7125                                                 start + len - 1, 0);
7126                 }
7127                 em = ERR_PTR(ret);
7128         }
7129  out:
7130
7131         return em;
7132 }
7133
7134 static struct extent_map *btrfs_new_extent_direct(struct inode *inode,
7135                                                   u64 start, u64 len)
7136 {
7137         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
7138         struct btrfs_root *root = BTRFS_I(inode)->root;
7139         struct extent_map *em;
7140         struct btrfs_key ins;
7141         u64 alloc_hint;
7142         int ret;
7143
7144         alloc_hint = get_extent_allocation_hint(inode, start, len);
7145         ret = btrfs_reserve_extent(root, len, len, fs_info->sectorsize,
7146                                    0, alloc_hint, &ins, 1, 1);
7147         if (ret)
7148                 return ERR_PTR(ret);
7149
7150         em = btrfs_create_dio_extent(inode, start, ins.offset, start,
7151                                      ins.objectid, ins.offset, ins.offset,
7152                                      ins.offset, BTRFS_ORDERED_REGULAR);
7153         btrfs_dec_block_group_reservations(fs_info, ins.objectid);
7154         if (IS_ERR(em))
7155                 btrfs_free_reserved_extent(fs_info, ins.objectid,
7156                                            ins.offset, 1);
7157
7158         return em;
7159 }
7160
7161 /*
7162  * returns 1 when the nocow is safe, < 1 on error, 0 if the
7163  * block must be cow'd
7164  */
7165 noinline int can_nocow_extent(struct inode *inode, u64 offset, u64 *len,
7166                               u64 *orig_start, u64 *orig_block_len,
7167                               u64 *ram_bytes)
7168 {
7169         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
7170         struct btrfs_path *path;
7171         int ret;
7172         struct extent_buffer *leaf;
7173         struct btrfs_root *root = BTRFS_I(inode)->root;
7174         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
7175         struct btrfs_file_extent_item *fi;
7176         struct btrfs_key key;
7177         u64 disk_bytenr;
7178         u64 backref_offset;
7179         u64 extent_end;
7180         u64 num_bytes;
7181         int slot;
7182         int found_type;
7183         bool nocow = (BTRFS_I(inode)->flags & BTRFS_INODE_NODATACOW);
7184
7185         path = btrfs_alloc_path();
7186         if (!path)
7187                 return -ENOMEM;
7188
7189         ret = btrfs_lookup_file_extent(NULL, root, path,
7190                         btrfs_ino(BTRFS_I(inode)), offset, 0);
7191         if (ret < 0)
7192                 goto out;
7193
7194         slot = path->slots[0];
7195         if (ret == 1) {
7196                 if (slot == 0) {
7197                         /* can't find the item, must cow */
7198                         ret = 0;
7199                         goto out;
7200                 }
7201                 slot--;
7202         }
7203         ret = 0;
7204         leaf = path->nodes[0];
7205         btrfs_item_key_to_cpu(leaf, &key, slot);
7206         if (key.objectid != btrfs_ino(BTRFS_I(inode)) ||
7207             key.type != BTRFS_EXTENT_DATA_KEY) {
7208                 /* not our file or wrong item type, must cow */
7209                 goto out;
7210         }
7211
7212         if (key.offset > offset) {
7213                 /* Wrong offset, must cow */
7214                 goto out;
7215         }
7216
7217         fi = btrfs_item_ptr(leaf, slot, struct btrfs_file_extent_item);
7218         found_type = btrfs_file_extent_type(leaf, fi);
7219         if (found_type != BTRFS_FILE_EXTENT_REG &&
7220             found_type != BTRFS_FILE_EXTENT_PREALLOC) {
7221                 /* not a regular extent, must cow */
7222                 goto out;
7223         }
7224
7225         if (!nocow && found_type == BTRFS_FILE_EXTENT_REG)
7226                 goto out;
7227
7228         extent_end = key.offset + btrfs_file_extent_num_bytes(leaf, fi);
7229         if (extent_end <= offset)
7230                 goto out;
7231
7232         disk_bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
7233         if (disk_bytenr == 0)
7234                 goto out;
7235
7236         if (btrfs_file_extent_compression(leaf, fi) ||
7237             btrfs_file_extent_encryption(leaf, fi) ||
7238             btrfs_file_extent_other_encoding(leaf, fi))
7239                 goto out;
7240
7241         /*
7242          * Do the same check as in btrfs_cross_ref_exist but without the
7243          * unnecessary search.
7244          */
7245         if (btrfs_file_extent_generation(leaf, fi) <=
7246             btrfs_root_last_snapshot(&root->root_item))
7247                 goto out;
7248
7249         backref_offset = btrfs_file_extent_offset(leaf, fi);
7250
7251         if (orig_start) {
7252                 *orig_start = key.offset - backref_offset;
7253                 *orig_block_len = btrfs_file_extent_disk_num_bytes(leaf, fi);
7254                 *ram_bytes = btrfs_file_extent_ram_bytes(leaf, fi);
7255         }
7256
7257         if (btrfs_extent_readonly(fs_info, disk_bytenr))
7258                 goto out;
7259
7260         num_bytes = min(offset + *len, extent_end) - offset;
7261         if (!nocow && found_type == BTRFS_FILE_EXTENT_PREALLOC) {
7262                 u64 range_end;
7263
7264                 range_end = round_up(offset + num_bytes,
7265                                      root->fs_info->sectorsize) - 1;
7266                 ret = test_range_bit(io_tree, offset, range_end,
7267                                      EXTENT_DELALLOC, 0, NULL);
7268                 if (ret) {
7269                         ret = -EAGAIN;
7270                         goto out;
7271                 }
7272         }
7273
7274         btrfs_release_path(path);
7275
7276         /*
7277          * look for other files referencing this extent, if we
7278          * find any we must cow
7279          */
7280
7281         ret = btrfs_cross_ref_exist(root, btrfs_ino(BTRFS_I(inode)),
7282                                     key.offset - backref_offset, disk_bytenr);
7283         if (ret) {
7284                 ret = 0;
7285                 goto out;
7286         }
7287
7288         /*
7289          * adjust disk_bytenr and num_bytes to cover just the bytes
7290          * in this extent we are about to write.  If there
7291          * are any csums in that range we have to cow in order
7292          * to keep the csums correct
7293          */
7294         disk_bytenr += backref_offset;
7295         disk_bytenr += offset - key.offset;
7296         if (csum_exist_in_range(fs_info, disk_bytenr, num_bytes))
7297                 goto out;
7298         /*
7299          * all of the above have passed, it is safe to overwrite this extent
7300          * without cow
7301          */
7302         *len = num_bytes;
7303         ret = 1;
7304 out:
7305         btrfs_free_path(path);
7306         return ret;
7307 }
7308
7309 static int lock_extent_direct(struct inode *inode, u64 lockstart, u64 lockend,
7310                               struct extent_state **cached_state, int writing)
7311 {
7312         struct btrfs_ordered_extent *ordered;
7313         int ret = 0;
7314
7315         while (1) {
7316                 lock_extent_bits(&BTRFS_I(inode)->io_tree, lockstart, lockend,
7317                                  cached_state);
7318                 /*
7319                  * We're concerned with the entire range that we're going to be
7320                  * doing DIO to, so we need to make sure there's no ordered
7321                  * extents in this range.
7322                  */
7323                 ordered = btrfs_lookup_ordered_range(BTRFS_I(inode), lockstart,
7324                                                      lockend - lockstart + 1);
7325
7326                 /*
7327                  * We need to make sure there are no buffered pages in this
7328                  * range either, we could have raced between the invalidate in
7329                  * generic_file_direct_write and locking the extent.  The
7330                  * invalidate needs to happen so that reads after a write do not
7331                  * get stale data.
7332                  */
7333                 if (!ordered &&
7334                     (!writing || !filemap_range_has_page(inode->i_mapping,
7335                                                          lockstart, lockend)))
7336                         break;
7337
7338                 unlock_extent_cached(&BTRFS_I(inode)->io_tree, lockstart, lockend,
7339                                      cached_state);
7340
7341                 if (ordered) {
7342                         /*
7343                          * If we are doing a DIO read and the ordered extent we
7344                          * found is for a buffered write, we can not wait for it
7345                          * to complete and retry, because if we do so we can
7346                          * deadlock with concurrent buffered writes on page
7347                          * locks. This happens only if our DIO read covers more
7348                          * than one extent map, if at this point has already
7349                          * created an ordered extent for a previous extent map
7350                          * and locked its range in the inode's io tree, and a
7351                          * concurrent write against that previous extent map's
7352                          * range and this range started (we unlock the ranges
7353                          * in the io tree only when the bios complete and
7354                          * buffered writes always lock pages before attempting
7355                          * to lock range in the io tree).
7356                          */
7357                         if (writing ||
7358                             test_bit(BTRFS_ORDERED_DIRECT, &ordered->flags))
7359                                 btrfs_start_ordered_extent(inode, ordered, 1);
7360                         else
7361                                 ret = -ENOTBLK;
7362                         btrfs_put_ordered_extent(ordered);
7363                 } else {
7364                         /*
7365                          * We could trigger writeback for this range (and wait
7366                          * for it to complete) and then invalidate the pages for
7367                          * this range (through invalidate_inode_pages2_range()),
7368                          * but that can lead us to a deadlock with a concurrent
7369                          * call to readpages() (a buffered read or a defrag call
7370                          * triggered a readahead) on a page lock due to an
7371                          * ordered dio extent we created before but did not have
7372                          * yet a corresponding bio submitted (whence it can not
7373                          * complete), which makes readpages() wait for that
7374                          * ordered extent to complete while holding a lock on
7375                          * that page.
7376                          */
7377                         ret = -ENOTBLK;
7378                 }
7379
7380                 if (ret)
7381                         break;
7382
7383                 cond_resched();
7384         }
7385
7386         return ret;
7387 }
7388
7389 /* The callers of this must take lock_extent() */
7390 static struct extent_map *create_io_em(struct inode *inode, u64 start, u64 len,
7391                                        u64 orig_start, u64 block_start,
7392                                        u64 block_len, u64 orig_block_len,
7393                                        u64 ram_bytes, int compress_type,
7394                                        int type)
7395 {
7396         struct extent_map_tree *em_tree;
7397         struct extent_map *em;
7398         struct btrfs_root *root = BTRFS_I(inode)->root;
7399         int ret;
7400
7401         ASSERT(type == BTRFS_ORDERED_PREALLOC ||
7402                type == BTRFS_ORDERED_COMPRESSED ||
7403                type == BTRFS_ORDERED_NOCOW ||
7404                type == BTRFS_ORDERED_REGULAR);
7405
7406         em_tree = &BTRFS_I(inode)->extent_tree;
7407         em = alloc_extent_map();
7408         if (!em)
7409                 return ERR_PTR(-ENOMEM);
7410
7411         em->start = start;
7412         em->orig_start = orig_start;
7413         em->len = len;
7414         em->block_len = block_len;
7415         em->block_start = block_start;
7416         em->bdev = root->fs_info->fs_devices->latest_bdev;
7417         em->orig_block_len = orig_block_len;
7418         em->ram_bytes = ram_bytes;
7419         em->generation = -1;
7420         set_bit(EXTENT_FLAG_PINNED, &em->flags);
7421         if (type == BTRFS_ORDERED_PREALLOC) {
7422                 set_bit(EXTENT_FLAG_FILLING, &em->flags);
7423         } else if (type == BTRFS_ORDERED_COMPRESSED) {
7424                 set_bit(EXTENT_FLAG_COMPRESSED, &em->flags);
7425                 em->compress_type = compress_type;
7426         }
7427
7428         do {
7429                 btrfs_drop_extent_cache(BTRFS_I(inode), em->start,
7430                                 em->start + em->len - 1, 0);
7431                 write_lock(&em_tree->lock);
7432                 ret = add_extent_mapping(em_tree, em, 1);
7433                 write_unlock(&em_tree->lock);
7434                 /*
7435                  * The caller has taken lock_extent(), who could race with us
7436                  * to add em?
7437                  */
7438         } while (ret == -EEXIST);
7439
7440         if (ret) {
7441                 free_extent_map(em);
7442                 return ERR_PTR(ret);
7443         }
7444
7445         /* em got 2 refs now, callers needs to do free_extent_map once. */
7446         return em;
7447 }
7448
7449
7450 static int btrfs_get_blocks_direct_read(struct extent_map *em,
7451                                         struct buffer_head *bh_result,
7452                                         struct inode *inode,
7453                                         u64 start, u64 len)
7454 {
7455         if (em->block_start == EXTENT_MAP_HOLE ||
7456                         test_bit(EXTENT_FLAG_PREALLOC, &em->flags))
7457                 return -ENOENT;
7458
7459         len = min(len, em->len - (start - em->start));
7460
7461         bh_result->b_blocknr = (em->block_start + (start - em->start)) >>
7462                 inode->i_blkbits;
7463         bh_result->b_size = len;
7464         bh_result->b_bdev = em->bdev;
7465         set_buffer_mapped(bh_result);
7466
7467         return 0;
7468 }
7469
7470 static int btrfs_get_blocks_direct_write(struct extent_map **map,
7471                                          struct buffer_head *bh_result,
7472                                          struct inode *inode,
7473                                          struct btrfs_dio_data *dio_data,
7474                                          u64 start, u64 len)
7475 {
7476         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
7477         struct extent_map *em = *map;
7478         int ret = 0;
7479
7480         /*
7481          * We don't allocate a new extent in the following cases
7482          *
7483          * 1) The inode is marked as NODATACOW. In this case we'll just use the
7484          * existing extent.
7485          * 2) The extent is marked as PREALLOC. We're good to go here and can
7486          * just use the extent.
7487          *
7488          */
7489         if (test_bit(EXTENT_FLAG_PREALLOC, &em->flags) ||
7490             ((BTRFS_I(inode)->flags & BTRFS_INODE_NODATACOW) &&
7491              em->block_start != EXTENT_MAP_HOLE)) {
7492                 int type;
7493                 u64 block_start, orig_start, orig_block_len, ram_bytes;
7494
7495                 if (test_bit(EXTENT_FLAG_PREALLOC, &em->flags))
7496                         type = BTRFS_ORDERED_PREALLOC;
7497                 else
7498                         type = BTRFS_ORDERED_NOCOW;
7499                 len = min(len, em->len - (start - em->start));
7500                 block_start = em->block_start + (start - em->start);
7501
7502                 if (can_nocow_extent(inode, start, &len, &orig_start,
7503                                      &orig_block_len, &ram_bytes) == 1 &&
7504                     btrfs_inc_nocow_writers(fs_info, block_start)) {
7505                         struct extent_map *em2;
7506
7507                         em2 = btrfs_create_dio_extent(inode, start, len,
7508                                                       orig_start, block_start,
7509                                                       len, orig_block_len,
7510                                                       ram_bytes, type);
7511                         btrfs_dec_nocow_writers(fs_info, block_start);
7512                         if (type == BTRFS_ORDERED_PREALLOC) {
7513                                 free_extent_map(em);
7514                                 *map = em = em2;
7515                         }
7516
7517                         if (em2 && IS_ERR(em2)) {
7518                                 ret = PTR_ERR(em2);
7519                                 goto out;
7520                         }
7521                         /*
7522                          * For inode marked NODATACOW or extent marked PREALLOC,
7523                          * use the existing or preallocated extent, so does not
7524                          * need to adjust btrfs_space_info's bytes_may_use.
7525                          */
7526                         btrfs_free_reserved_data_space_noquota(inode, start,
7527                                                                len);
7528                         goto skip_cow;
7529                 }
7530         }
7531
7532         /* this will cow the extent */
7533         len = bh_result->b_size;
7534         free_extent_map(em);
7535         *map = em = btrfs_new_extent_direct(inode, start, len);
7536         if (IS_ERR(em)) {
7537                 ret = PTR_ERR(em);
7538                 goto out;
7539         }
7540
7541         len = min(len, em->len - (start - em->start));
7542
7543 skip_cow:
7544         bh_result->b_blocknr = (em->block_start + (start - em->start)) >>
7545                 inode->i_blkbits;
7546         bh_result->b_size = len;
7547         bh_result->b_bdev = em->bdev;
7548         set_buffer_mapped(bh_result);
7549
7550         if (!test_bit(EXTENT_FLAG_PREALLOC, &em->flags))
7551                 set_buffer_new(bh_result);
7552
7553         /*
7554          * Need to update the i_size under the extent lock so buffered
7555          * readers will get the updated i_size when we unlock.
7556          */
7557         if (!dio_data->overwrite && start + len > i_size_read(inode))
7558                 i_size_write(inode, start + len);
7559
7560         WARN_ON(dio_data->reserve < len);
7561         dio_data->reserve -= len;
7562         dio_data->unsubmitted_oe_range_end = start + len;
7563         current->journal_info = dio_data;
7564 out:
7565         return ret;
7566 }
7567
7568 static int btrfs_get_blocks_direct(struct inode *inode, sector_t iblock,
7569                                    struct buffer_head *bh_result, int create)
7570 {
7571         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
7572         struct extent_map *em;
7573         struct extent_state *cached_state = NULL;
7574         struct btrfs_dio_data *dio_data = NULL;
7575         u64 start = iblock << inode->i_blkbits;
7576         u64 lockstart, lockend;
7577         u64 len = bh_result->b_size;
7578         int unlock_bits = EXTENT_LOCKED;
7579         int ret = 0;
7580
7581         if (create)
7582                 unlock_bits |= EXTENT_DIRTY;
7583         else
7584                 len = min_t(u64, len, fs_info->sectorsize);
7585
7586         lockstart = start;
7587         lockend = start + len - 1;
7588
7589         if (current->journal_info) {
7590                 /*
7591                  * Need to pull our outstanding extents and set journal_info to NULL so
7592                  * that anything that needs to check if there's a transaction doesn't get
7593                  * confused.
7594                  */
7595                 dio_data = current->journal_info;
7596                 current->journal_info = NULL;
7597         }
7598
7599         /*
7600          * If this errors out it's because we couldn't invalidate pagecache for
7601          * this range and we need to fallback to buffered.
7602          */
7603         if (lock_extent_direct(inode, lockstart, lockend, &cached_state,
7604                                create)) {
7605                 ret = -ENOTBLK;
7606                 goto err;
7607         }
7608
7609         em = btrfs_get_extent(BTRFS_I(inode), NULL, 0, start, len, 0);
7610         if (IS_ERR(em)) {
7611                 ret = PTR_ERR(em);
7612                 goto unlock_err;
7613         }
7614
7615         /*
7616          * Ok for INLINE and COMPRESSED extents we need to fallback on buffered
7617          * io.  INLINE is special, and we could probably kludge it in here, but
7618          * it's still buffered so for safety lets just fall back to the generic
7619          * buffered path.
7620          *
7621          * For COMPRESSED we _have_ to read the entire extent in so we can
7622          * decompress it, so there will be buffering required no matter what we
7623          * do, so go ahead and fallback to buffered.
7624          *
7625          * We return -ENOTBLK because that's what makes DIO go ahead and go back
7626          * to buffered IO.  Don't blame me, this is the price we pay for using
7627          * the generic code.
7628          */
7629         if (test_bit(EXTENT_FLAG_COMPRESSED, &em->flags) ||
7630             em->block_start == EXTENT_MAP_INLINE) {
7631                 free_extent_map(em);
7632                 ret = -ENOTBLK;
7633                 goto unlock_err;
7634         }
7635
7636         if (create) {
7637                 ret = btrfs_get_blocks_direct_write(&em, bh_result, inode,
7638                                                     dio_data, start, len);
7639                 if (ret < 0)
7640                         goto unlock_err;
7641
7642                 /* clear and unlock the entire range */
7643                 clear_extent_bit(&BTRFS_I(inode)->io_tree, lockstart, lockend,
7644                                  unlock_bits, 1, 0, &cached_state);
7645         } else {
7646                 ret = btrfs_get_blocks_direct_read(em, bh_result, inode,
7647                                                    start, len);
7648                 /* Can be negative only if we read from a hole */
7649                 if (ret < 0) {
7650                         ret = 0;
7651                         free_extent_map(em);
7652                         goto unlock_err;
7653                 }
7654                 /*
7655                  * We need to unlock only the end area that we aren't using.
7656                  * The rest is going to be unlocked by the endio routine.
7657                  */
7658                 lockstart = start + bh_result->b_size;
7659                 if (lockstart < lockend) {
7660                         clear_extent_bit(&BTRFS_I(inode)->io_tree, lockstart,
7661                                          lockend, unlock_bits, 1, 0,
7662                                          &cached_state);
7663                 } else {
7664                         free_extent_state(cached_state);
7665                 }
7666         }
7667
7668         free_extent_map(em);
7669
7670         return 0;
7671
7672 unlock_err:
7673         clear_extent_bit(&BTRFS_I(inode)->io_tree, lockstart, lockend,
7674                          unlock_bits, 1, 0, &cached_state);
7675 err:
7676         if (dio_data)
7677                 current->journal_info = dio_data;
7678         return ret;
7679 }
7680
7681 static inline blk_status_t submit_dio_repair_bio(struct inode *inode,
7682                                                  struct bio *bio,
7683                                                  int mirror_num)
7684 {
7685         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
7686         blk_status_t ret;
7687
7688         BUG_ON(bio_op(bio) == REQ_OP_WRITE);
7689
7690         ret = btrfs_bio_wq_end_io(fs_info, bio, BTRFS_WQ_ENDIO_DIO_REPAIR);
7691         if (ret)
7692                 return ret;
7693
7694         ret = btrfs_map_bio(fs_info, bio, mirror_num, 0);
7695
7696         return ret;
7697 }
7698
7699 static int btrfs_check_dio_repairable(struct inode *inode,
7700                                       struct bio *failed_bio,
7701                                       struct io_failure_record *failrec,
7702                                       int failed_mirror)
7703 {
7704         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
7705         int num_copies;
7706
7707         num_copies = btrfs_num_copies(fs_info, failrec->logical, failrec->len);
7708         if (num_copies == 1) {
7709                 /*
7710                  * we only have a single copy of the data, so don't bother with
7711                  * all the retry and error correction code that follows. no
7712                  * matter what the error is, it is very likely to persist.
7713                  */
7714                 btrfs_debug(fs_info,
7715                         "Check DIO Repairable: cannot repair, num_copies=%d, next_mirror %d, failed_mirror %d",
7716                         num_copies, failrec->this_mirror, failed_mirror);
7717                 return 0;
7718         }
7719
7720         failrec->failed_mirror = failed_mirror;
7721         failrec->this_mirror++;
7722         if (failrec->this_mirror == failed_mirror)
7723                 failrec->this_mirror++;
7724
7725         if (failrec->this_mirror > num_copies) {
7726                 btrfs_debug(fs_info,
7727                         "Check DIO Repairable: (fail) num_copies=%d, next_mirror %d, failed_mirror %d",
7728                         num_copies, failrec->this_mirror, failed_mirror);
7729                 return 0;
7730         }
7731
7732         return 1;
7733 }
7734
7735 static blk_status_t dio_read_error(struct inode *inode, struct bio *failed_bio,
7736                                    struct page *page, unsigned int pgoff,
7737                                    u64 start, u64 end, int failed_mirror,
7738                                    bio_end_io_t *repair_endio, void *repair_arg)
7739 {
7740         struct io_failure_record *failrec;
7741         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
7742         struct extent_io_tree *failure_tree = &BTRFS_I(inode)->io_failure_tree;
7743         struct bio *bio;
7744         int isector;
7745         unsigned int read_mode = 0;
7746         int segs;
7747         int ret;
7748         blk_status_t status;
7749         struct bio_vec bvec;
7750
7751         BUG_ON(bio_op(failed_bio) == REQ_OP_WRITE);
7752
7753         ret = btrfs_get_io_failure_record(inode, start, end, &failrec);
7754         if (ret)
7755                 return errno_to_blk_status(ret);
7756
7757         ret = btrfs_check_dio_repairable(inode, failed_bio, failrec,
7758                                          failed_mirror);
7759         if (!ret) {
7760                 free_io_failure(failure_tree, io_tree, failrec);
7761                 return BLK_STS_IOERR;
7762         }
7763
7764         segs = bio_segments(failed_bio);
7765         bio_get_first_bvec(failed_bio, &bvec);
7766         if (segs > 1 ||
7767             (bvec.bv_len > btrfs_inode_sectorsize(inode)))
7768                 read_mode |= REQ_FAILFAST_DEV;
7769
7770         isector = start - btrfs_io_bio(failed_bio)->logical;
7771         isector >>= inode->i_sb->s_blocksize_bits;
7772         bio = btrfs_create_repair_bio(inode, failed_bio, failrec, page,
7773                                 pgoff, isector, repair_endio, repair_arg);
7774         bio->bi_opf = REQ_OP_READ | read_mode;
7775
7776         btrfs_debug(BTRFS_I(inode)->root->fs_info,
7777                     "repair DIO read error: submitting new dio read[%#x] to this_mirror=%d, in_validation=%d",
7778                     read_mode, failrec->this_mirror, failrec->in_validation);
7779
7780         status = submit_dio_repair_bio(inode, bio, failrec->this_mirror);
7781         if (status) {
7782                 free_io_failure(failure_tree, io_tree, failrec);
7783                 bio_put(bio);
7784         }
7785
7786         return status;
7787 }
7788
7789 struct btrfs_retry_complete {
7790         struct completion done;
7791         struct inode *inode;
7792         u64 start;
7793         int uptodate;
7794 };
7795
7796 static void btrfs_retry_endio_nocsum(struct bio *bio)
7797 {
7798         struct btrfs_retry_complete *done = bio->bi_private;
7799         struct inode *inode = done->inode;
7800         struct bio_vec *bvec;
7801         struct extent_io_tree *io_tree, *failure_tree;
7802         int i;
7803
7804         if (bio->bi_status)
7805                 goto end;
7806
7807         ASSERT(bio->bi_vcnt == 1);
7808         io_tree = &BTRFS_I(inode)->io_tree;
7809         failure_tree = &BTRFS_I(inode)->io_failure_tree;
7810         ASSERT(bio_first_bvec_all(bio)->bv_len == btrfs_inode_sectorsize(inode));
7811
7812         done->uptodate = 1;
7813         ASSERT(!bio_flagged(bio, BIO_CLONED));
7814         bio_for_each_segment_all(bvec, bio, i)
7815                 clean_io_failure(BTRFS_I(inode)->root->fs_info, failure_tree,
7816                                  io_tree, done->start, bvec->bv_page,
7817                                  btrfs_ino(BTRFS_I(inode)), 0);
7818 end:
7819         complete(&done->done);
7820         bio_put(bio);
7821 }
7822
7823 static blk_status_t __btrfs_correct_data_nocsum(struct inode *inode,
7824                                                 struct btrfs_io_bio *io_bio)
7825 {
7826         struct btrfs_fs_info *fs_info;
7827         struct bio_vec bvec;
7828         struct bvec_iter iter;
7829         struct btrfs_retry_complete done;
7830         u64 start;
7831         unsigned int pgoff;
7832         u32 sectorsize;
7833         int nr_sectors;
7834         blk_status_t ret;
7835         blk_status_t err = BLK_STS_OK;
7836
7837         fs_info = BTRFS_I(inode)->root->fs_info;
7838         sectorsize = fs_info->sectorsize;
7839
7840         start = io_bio->logical;
7841         done.inode = inode;
7842         io_bio->bio.bi_iter = io_bio->iter;
7843
7844         bio_for_each_segment(bvec, &io_bio->bio, iter) {
7845                 nr_sectors = BTRFS_BYTES_TO_BLKS(fs_info, bvec.bv_len);
7846                 pgoff = bvec.bv_offset;
7847
7848 next_block_or_try_again:
7849                 done.uptodate = 0;
7850                 done.start = start;
7851                 init_completion(&done.done);
7852
7853                 ret = dio_read_error(inode, &io_bio->bio, bvec.bv_page,
7854                                 pgoff, start, start + sectorsize - 1,
7855                                 io_bio->mirror_num,
7856                                 btrfs_retry_endio_nocsum, &done);
7857                 if (ret) {
7858                         err = ret;
7859                         goto next;
7860                 }
7861
7862                 wait_for_completion_io(&done.done);
7863
7864                 if (!done.uptodate) {
7865                         /* We might have another mirror, so try again */
7866                         goto next_block_or_try_again;
7867                 }
7868
7869 next:
7870                 start += sectorsize;
7871
7872                 nr_sectors--;
7873                 if (nr_sectors) {
7874                         pgoff += sectorsize;
7875                         ASSERT(pgoff < PAGE_SIZE);
7876                         goto next_block_or_try_again;
7877                 }
7878         }
7879
7880         return err;
7881 }
7882
7883 static void btrfs_retry_endio(struct bio *bio)
7884 {
7885         struct btrfs_retry_complete *done = bio->bi_private;
7886         struct btrfs_io_bio *io_bio = btrfs_io_bio(bio);
7887         struct extent_io_tree *io_tree, *failure_tree;
7888         struct inode *inode = done->inode;
7889         struct bio_vec *bvec;
7890         int uptodate;
7891         int ret;
7892         int i;
7893
7894         if (bio->bi_status)
7895                 goto end;
7896
7897         uptodate = 1;
7898
7899         ASSERT(bio->bi_vcnt == 1);
7900         ASSERT(bio_first_bvec_all(bio)->bv_len == btrfs_inode_sectorsize(done->inode));
7901
7902         io_tree = &BTRFS_I(inode)->io_tree;
7903         failure_tree = &BTRFS_I(inode)->io_failure_tree;
7904
7905         ASSERT(!bio_flagged(bio, BIO_CLONED));
7906         bio_for_each_segment_all(bvec, bio, i) {
7907                 ret = __readpage_endio_check(inode, io_bio, i, bvec->bv_page,
7908                                              bvec->bv_offset, done->start,
7909                                              bvec->bv_len);
7910                 if (!ret)
7911                         clean_io_failure(BTRFS_I(inode)->root->fs_info,
7912                                          failure_tree, io_tree, done->start,
7913                                          bvec->bv_page,
7914                                          btrfs_ino(BTRFS_I(inode)),
7915                                          bvec->bv_offset);
7916                 else
7917                         uptodate = 0;
7918         }
7919
7920         done->uptodate = uptodate;
7921 end:
7922         complete(&done->done);
7923         bio_put(bio);
7924 }
7925
7926 static blk_status_t __btrfs_subio_endio_read(struct inode *inode,
7927                 struct btrfs_io_bio *io_bio, blk_status_t err)
7928 {
7929         struct btrfs_fs_info *fs_info;
7930         struct bio_vec bvec;
7931         struct bvec_iter iter;
7932         struct btrfs_retry_complete done;
7933         u64 start;
7934         u64 offset = 0;
7935         u32 sectorsize;
7936         int nr_sectors;
7937         unsigned int pgoff;
7938         int csum_pos;
7939         bool uptodate = (err == 0);
7940         int ret;
7941         blk_status_t status;
7942
7943         fs_info = BTRFS_I(inode)->root->fs_info;
7944         sectorsize = fs_info->sectorsize;
7945
7946         err = BLK_STS_OK;
7947         start = io_bio->logical;
7948         done.inode = inode;
7949         io_bio->bio.bi_iter = io_bio->iter;
7950
7951         bio_for_each_segment(bvec, &io_bio->bio, iter) {
7952                 nr_sectors = BTRFS_BYTES_TO_BLKS(fs_info, bvec.bv_len);
7953
7954                 pgoff = bvec.bv_offset;
7955 next_block:
7956                 if (uptodate) {
7957                         csum_pos = BTRFS_BYTES_TO_BLKS(fs_info, offset);
7958                         ret = __readpage_endio_check(inode, io_bio, csum_pos,
7959                                         bvec.bv_page, pgoff, start, sectorsize);
7960                         if (likely(!ret))
7961                                 goto next;
7962                 }
7963 try_again:
7964                 done.uptodate = 0;
7965                 done.start = start;
7966                 init_completion(&done.done);
7967
7968                 status = dio_read_error(inode, &io_bio->bio, bvec.bv_page,
7969                                         pgoff, start, start + sectorsize - 1,
7970                                         io_bio->mirror_num, btrfs_retry_endio,
7971                                         &done);
7972                 if (status) {
7973                         err = status;
7974                         goto next;
7975                 }
7976
7977                 wait_for_completion_io(&done.done);
7978
7979                 if (!done.uptodate) {
7980                         /* We might have another mirror, so try again */
7981                         goto try_again;
7982                 }
7983 next:
7984                 offset += sectorsize;
7985                 start += sectorsize;
7986
7987                 ASSERT(nr_sectors);
7988
7989                 nr_sectors--;
7990                 if (nr_sectors) {
7991                         pgoff += sectorsize;
7992                         ASSERT(pgoff < PAGE_SIZE);
7993                         goto next_block;
7994                 }
7995         }
7996
7997         return err;
7998 }
7999
8000 static blk_status_t btrfs_subio_endio_read(struct inode *inode,
8001                 struct btrfs_io_bio *io_bio, blk_status_t err)
8002 {
8003         bool skip_csum = BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM;
8004
8005         if (skip_csum) {
8006                 if (unlikely(err))
8007                         return __btrfs_correct_data_nocsum(inode, io_bio);
8008                 else
8009                         return BLK_STS_OK;
8010         } else {
8011                 return __btrfs_subio_endio_read(inode, io_bio, err);
8012         }
8013 }
8014
8015 static void btrfs_endio_direct_read(struct bio *bio)
8016 {
8017         struct btrfs_dio_private *dip = bio->bi_private;
8018         struct inode *inode = dip->inode;
8019         struct bio *dio_bio;
8020         struct btrfs_io_bio *io_bio = btrfs_io_bio(bio);
8021         blk_status_t err = bio->bi_status;
8022
8023         if (dip->flags & BTRFS_DIO_ORIG_BIO_SUBMITTED)
8024                 err = btrfs_subio_endio_read(inode, io_bio, err);
8025
8026         unlock_extent(&BTRFS_I(inode)->io_tree, dip->logical_offset,
8027                       dip->logical_offset + dip->bytes - 1);
8028         dio_bio = dip->dio_bio;
8029
8030         kfree(dip);
8031
8032         dio_bio->bi_status = err;
8033         dio_end_io(dio_bio);
8034
8035         if (io_bio->end_io)
8036                 io_bio->end_io(io_bio, blk_status_to_errno(err));
8037         bio_put(bio);
8038 }
8039
8040 static void __endio_write_update_ordered(struct inode *inode,
8041                                          const u64 offset, const u64 bytes,
8042                                          const bool uptodate)
8043 {
8044         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
8045         struct btrfs_ordered_extent *ordered = NULL;
8046         struct btrfs_workqueue *wq;
8047         btrfs_work_func_t func;
8048         u64 ordered_offset = offset;
8049         u64 ordered_bytes = bytes;
8050         u64 last_offset;
8051
8052         if (btrfs_is_free_space_inode(BTRFS_I(inode))) {
8053                 wq = fs_info->endio_freespace_worker;
8054                 func = btrfs_freespace_write_helper;
8055         } else {
8056                 wq = fs_info->endio_write_workers;
8057                 func = btrfs_endio_write_helper;
8058         }
8059
8060         while (ordered_offset < offset + bytes) {
8061                 last_offset = ordered_offset;
8062                 if (btrfs_dec_test_first_ordered_pending(inode, &ordered,
8063                                                            &ordered_offset,
8064                                                            ordered_bytes,
8065                                                            uptodate)) {
8066                         btrfs_init_work(&ordered->work, func,
8067                                         finish_ordered_fn,
8068                                         NULL, NULL);
8069                         btrfs_queue_work(wq, &ordered->work);
8070                 }
8071                 /*
8072                  * If btrfs_dec_test_ordered_pending does not find any ordered
8073                  * extent in the range, we can exit.
8074                  */
8075                 if (ordered_offset == last_offset)
8076                         return;
8077                 /*
8078                  * Our bio might span multiple ordered extents. In this case
8079                  * we keep goin until we have accounted the whole dio.
8080                  */
8081                 if (ordered_offset < offset + bytes) {
8082                         ordered_bytes = offset + bytes - ordered_offset;
8083                         ordered = NULL;
8084                 }
8085         }
8086 }
8087
8088 static void btrfs_endio_direct_write(struct bio *bio)
8089 {
8090         struct btrfs_dio_private *dip = bio->bi_private;
8091         struct bio *dio_bio = dip->dio_bio;
8092
8093         __endio_write_update_ordered(dip->inode, dip->logical_offset,
8094                                      dip->bytes, !bio->bi_status);
8095
8096         kfree(dip);
8097
8098         dio_bio->bi_status = bio->bi_status;
8099         dio_end_io(dio_bio);
8100         bio_put(bio);
8101 }
8102
8103 static blk_status_t btrfs_submit_bio_start_direct_io(void *private_data,
8104                                     struct bio *bio, u64 offset)
8105 {
8106         struct inode *inode = private_data;
8107         blk_status_t ret;
8108         ret = btrfs_csum_one_bio(inode, bio, offset, 1);
8109         BUG_ON(ret); /* -ENOMEM */
8110         return 0;
8111 }
8112
8113 static void btrfs_end_dio_bio(struct bio *bio)
8114 {
8115         struct btrfs_dio_private *dip = bio->bi_private;
8116         blk_status_t err = bio->bi_status;
8117
8118         if (err)
8119                 btrfs_warn(BTRFS_I(dip->inode)->root->fs_info,
8120                            "direct IO failed ino %llu rw %d,%u sector %#Lx len %u err no %d",
8121                            btrfs_ino(BTRFS_I(dip->inode)), bio_op(bio),
8122                            bio->bi_opf,
8123                            (unsigned long long)bio->bi_iter.bi_sector,
8124                            bio->bi_iter.bi_size, err);
8125
8126         if (dip->subio_endio)
8127                 err = dip->subio_endio(dip->inode, btrfs_io_bio(bio), err);
8128
8129         if (err) {
8130                 /*
8131                  * We want to perceive the errors flag being set before
8132                  * decrementing the reference count. We don't need a barrier
8133                  * since atomic operations with a return value are fully
8134                  * ordered as per atomic_t.txt
8135                  */
8136                 dip->errors = 1;
8137         }
8138
8139         /* if there are more bios still pending for this dio, just exit */
8140         if (!atomic_dec_and_test(&dip->pending_bios))
8141                 goto out;
8142
8143         if (dip->errors) {
8144                 bio_io_error(dip->orig_bio);
8145         } else {
8146                 dip->dio_bio->bi_status = BLK_STS_OK;
8147                 bio_endio(dip->orig_bio);
8148         }
8149 out:
8150         bio_put(bio);
8151 }
8152
8153 static inline blk_status_t btrfs_lookup_and_bind_dio_csum(struct inode *inode,
8154                                                  struct btrfs_dio_private *dip,
8155                                                  struct bio *bio,
8156                                                  u64 file_offset)
8157 {
8158         struct btrfs_io_bio *io_bio = btrfs_io_bio(bio);
8159         struct btrfs_io_bio *orig_io_bio = btrfs_io_bio(dip->orig_bio);
8160         blk_status_t ret;
8161
8162         /*
8163          * We load all the csum data we need when we submit
8164          * the first bio to reduce the csum tree search and
8165          * contention.
8166          */
8167         if (dip->logical_offset == file_offset) {
8168                 ret = btrfs_lookup_bio_sums_dio(inode, dip->orig_bio,
8169                                                 file_offset);
8170                 if (ret)
8171                         return ret;
8172         }
8173
8174         if (bio == dip->orig_bio)
8175                 return 0;
8176
8177         file_offset -= dip->logical_offset;
8178         file_offset >>= inode->i_sb->s_blocksize_bits;
8179         io_bio->csum = (u8 *)(((u32 *)orig_io_bio->csum) + file_offset);
8180
8181         return 0;
8182 }
8183
8184 static inline blk_status_t btrfs_submit_dio_bio(struct bio *bio,
8185                 struct inode *inode, u64 file_offset, int async_submit)
8186 {
8187         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
8188         struct btrfs_dio_private *dip = bio->bi_private;
8189         bool write = bio_op(bio) == REQ_OP_WRITE;
8190         blk_status_t ret;
8191
8192         /* Check btrfs_submit_bio_hook() for rules about async submit. */
8193         if (async_submit)
8194                 async_submit = !atomic_read(&BTRFS_I(inode)->sync_writers);
8195
8196         if (!write) {
8197                 ret = btrfs_bio_wq_end_io(fs_info, bio, BTRFS_WQ_ENDIO_DATA);
8198                 if (ret)
8199                         goto err;
8200         }
8201
8202         if (BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM)
8203                 goto map;
8204
8205         if (write && async_submit) {
8206                 ret = btrfs_wq_submit_bio(fs_info, bio, 0, 0,
8207                                           file_offset, inode,
8208                                           btrfs_submit_bio_start_direct_io);
8209                 goto err;
8210         } else if (write) {
8211                 /*
8212                  * If we aren't doing async submit, calculate the csum of the
8213                  * bio now.
8214                  */
8215                 ret = btrfs_csum_one_bio(inode, bio, file_offset, 1);
8216                 if (ret)
8217                         goto err;
8218         } else {
8219                 ret = btrfs_lookup_and_bind_dio_csum(inode, dip, bio,
8220                                                      file_offset);
8221                 if (ret)
8222                         goto err;
8223         }
8224 map:
8225         ret = btrfs_map_bio(fs_info, bio, 0, 0);
8226 err:
8227         return ret;
8228 }
8229
8230 static int btrfs_submit_direct_hook(struct btrfs_dio_private *dip)
8231 {
8232         struct inode *inode = dip->inode;
8233         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
8234         struct bio *bio;
8235         struct bio *orig_bio = dip->orig_bio;
8236         u64 start_sector = orig_bio->bi_iter.bi_sector;
8237         u64 file_offset = dip->logical_offset;
8238         u64 map_length;
8239         int async_submit = 0;
8240         u64 submit_len;
8241         int clone_offset = 0;
8242         int clone_len;
8243         int ret;
8244         blk_status_t status;
8245
8246         map_length = orig_bio->bi_iter.bi_size;
8247         submit_len = map_length;
8248         ret = btrfs_map_block(fs_info, btrfs_op(orig_bio), start_sector << 9,
8249                               &map_length, NULL, 0);
8250         if (ret)
8251                 return -EIO;
8252
8253         if (map_length >= submit_len) {
8254                 bio = orig_bio;
8255                 dip->flags |= BTRFS_DIO_ORIG_BIO_SUBMITTED;
8256                 goto submit;
8257         }
8258
8259         /* async crcs make it difficult to collect full stripe writes. */
8260         if (btrfs_data_alloc_profile(fs_info) & BTRFS_BLOCK_GROUP_RAID56_MASK)
8261                 async_submit = 0;
8262         else
8263                 async_submit = 1;
8264
8265         /* bio split */
8266         ASSERT(map_length <= INT_MAX);
8267         atomic_inc(&dip->pending_bios);
8268         do {
8269                 clone_len = min_t(int, submit_len, map_length);
8270
8271                 /*
8272                  * This will never fail as it's passing GPF_NOFS and
8273                  * the allocation is backed by btrfs_bioset.
8274                  */
8275                 bio = btrfs_bio_clone_partial(orig_bio, clone_offset,
8276                                               clone_len);
8277                 bio->bi_private = dip;
8278                 bio->bi_end_io = btrfs_end_dio_bio;
8279                 btrfs_io_bio(bio)->logical = file_offset;
8280
8281                 ASSERT(submit_len >= clone_len);
8282                 submit_len -= clone_len;
8283                 if (submit_len == 0)
8284                         break;
8285
8286                 /*
8287                  * Increase the count before we submit the bio so we know
8288                  * the end IO handler won't happen before we increase the
8289                  * count. Otherwise, the dip might get freed before we're
8290                  * done setting it up.
8291                  */
8292                 atomic_inc(&dip->pending_bios);
8293
8294                 status = btrfs_submit_dio_bio(bio, inode, file_offset,
8295                                                 async_submit);
8296                 if (status) {
8297                         bio_put(bio);
8298                         atomic_dec(&dip->pending_bios);
8299                         goto out_err;
8300                 }
8301
8302                 clone_offset += clone_len;
8303                 start_sector += clone_len >> 9;
8304                 file_offset += clone_len;
8305
8306                 map_length = submit_len;
8307                 ret = btrfs_map_block(fs_info, btrfs_op(orig_bio),
8308                                       start_sector << 9, &map_length, NULL, 0);
8309                 if (ret)
8310                         goto out_err;
8311         } while (submit_len > 0);
8312
8313 submit:
8314         status = btrfs_submit_dio_bio(bio, inode, file_offset, async_submit);
8315         if (!status)
8316                 return 0;
8317
8318         bio_put(bio);
8319 out_err:
8320         dip->errors = 1;
8321         /*
8322          * Before atomic variable goto zero, we must  make sure dip->errors is
8323          * perceived to be set. This ordering is ensured by the fact that an
8324          * atomic operations with a return value are fully ordered as per
8325          * atomic_t.txt
8326          */
8327         if (atomic_dec_and_test(&dip->pending_bios))
8328                 bio_io_error(dip->orig_bio);
8329
8330         /* bio_end_io() will handle error, so we needn't return it */
8331         return 0;
8332 }
8333
8334 static void btrfs_submit_direct(struct bio *dio_bio, struct inode *inode,
8335                                 loff_t file_offset)
8336 {
8337         struct btrfs_dio_private *dip = NULL;
8338         struct bio *bio = NULL;
8339         struct btrfs_io_bio *io_bio;
8340         bool write = (bio_op(dio_bio) == REQ_OP_WRITE);
8341         int ret = 0;
8342
8343         bio = btrfs_bio_clone(dio_bio);
8344
8345         dip = kzalloc(sizeof(*dip), GFP_NOFS);
8346         if (!dip) {
8347                 ret = -ENOMEM;
8348                 goto free_ordered;
8349         }
8350
8351         dip->private = dio_bio->bi_private;
8352         dip->inode = inode;
8353         dip->logical_offset = file_offset;
8354         dip->bytes = dio_bio->bi_iter.bi_size;
8355         dip->disk_bytenr = (u64)dio_bio->bi_iter.bi_sector << 9;
8356         bio->bi_private = dip;
8357         dip->orig_bio = bio;
8358         dip->dio_bio = dio_bio;
8359         atomic_set(&dip->pending_bios, 0);
8360         io_bio = btrfs_io_bio(bio);
8361         io_bio->logical = file_offset;
8362
8363         if (write) {
8364                 bio->bi_end_io = btrfs_endio_direct_write;
8365         } else {
8366                 bio->bi_end_io = btrfs_endio_direct_read;
8367                 dip->subio_endio = btrfs_subio_endio_read;
8368         }
8369
8370         /*
8371          * Reset the range for unsubmitted ordered extents (to a 0 length range)
8372          * even if we fail to submit a bio, because in such case we do the
8373          * corresponding error handling below and it must not be done a second
8374          * time by btrfs_direct_IO().
8375          */
8376         if (write) {
8377                 struct btrfs_dio_data *dio_data = current->journal_info;
8378
8379                 dio_data->unsubmitted_oe_range_end = dip->logical_offset +
8380                         dip->bytes;
8381                 dio_data->unsubmitted_oe_range_start =
8382                         dio_data->unsubmitted_oe_range_end;
8383         }
8384
8385         ret = btrfs_submit_direct_hook(dip);
8386         if (!ret)
8387                 return;
8388
8389         if (io_bio->end_io)
8390                 io_bio->end_io(io_bio, ret);
8391
8392 free_ordered:
8393         /*
8394          * If we arrived here it means either we failed to submit the dip
8395          * or we either failed to clone the dio_bio or failed to allocate the
8396          * dip. If we cloned the dio_bio and allocated the dip, we can just
8397          * call bio_endio against our io_bio so that we get proper resource
8398          * cleanup if we fail to submit the dip, otherwise, we must do the
8399          * same as btrfs_endio_direct_[write|read] because we can't call these
8400          * callbacks - they require an allocated dip and a clone of dio_bio.
8401          */
8402         if (bio && dip) {
8403                 bio_io_error(bio);
8404                 /*
8405                  * The end io callbacks free our dip, do the final put on bio
8406                  * and all the cleanup and final put for dio_bio (through
8407                  * dio_end_io()).
8408                  */
8409                 dip = NULL;
8410                 bio = NULL;
8411         } else {
8412                 if (write)
8413                         __endio_write_update_ordered(inode,
8414                                                 file_offset,
8415                                                 dio_bio->bi_iter.bi_size,
8416                                                 false);
8417                 else
8418                         unlock_extent(&BTRFS_I(inode)->io_tree, file_offset,
8419                               file_offset + dio_bio->bi_iter.bi_size - 1);
8420
8421                 dio_bio->bi_status = BLK_STS_IOERR;
8422                 /*
8423                  * Releases and cleans up our dio_bio, no need to bio_put()
8424                  * nor bio_endio()/bio_io_error() against dio_bio.
8425                  */
8426                 dio_end_io(dio_bio);
8427         }
8428         if (bio)
8429                 bio_put(bio);
8430         kfree(dip);
8431 }
8432
8433 static ssize_t check_direct_IO(struct btrfs_fs_info *fs_info,
8434                                const struct iov_iter *iter, loff_t offset)
8435 {
8436         int seg;
8437         int i;
8438         unsigned int blocksize_mask = fs_info->sectorsize - 1;
8439         ssize_t retval = -EINVAL;
8440
8441         if (offset & blocksize_mask)
8442                 goto out;
8443
8444         if (iov_iter_alignment(iter) & blocksize_mask)
8445                 goto out;
8446
8447         /* If this is a write we don't need to check anymore */
8448         if (iov_iter_rw(iter) != READ || !iter_is_iovec(iter))
8449                 return 0;
8450         /*
8451          * Check to make sure we don't have duplicate iov_base's in this
8452          * iovec, if so return EINVAL, otherwise we'll get csum errors
8453          * when reading back.
8454          */
8455         for (seg = 0; seg < iter->nr_segs; seg++) {
8456                 for (i = seg + 1; i < iter->nr_segs; i++) {
8457                         if (iter->iov[seg].iov_base == iter->iov[i].iov_base)
8458                                 goto out;
8459                 }
8460         }
8461         retval = 0;
8462 out:
8463         return retval;
8464 }
8465
8466 static ssize_t btrfs_direct_IO(struct kiocb *iocb, struct iov_iter *iter)
8467 {
8468         struct file *file = iocb->ki_filp;
8469         struct inode *inode = file->f_mapping->host;
8470         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
8471         struct btrfs_dio_data dio_data = { 0 };
8472         struct extent_changeset *data_reserved = NULL;
8473         loff_t offset = iocb->ki_pos;
8474         size_t count = 0;
8475         int flags = 0;
8476         bool wakeup = true;
8477         bool relock = false;
8478         ssize_t ret;
8479
8480         if (check_direct_IO(fs_info, iter, offset))
8481                 return 0;
8482
8483         inode_dio_begin(inode);
8484
8485         /*
8486          * The generic stuff only does filemap_write_and_wait_range, which
8487          * isn't enough if we've written compressed pages to this area, so
8488          * we need to flush the dirty pages again to make absolutely sure
8489          * that any outstanding dirty pages are on disk.
8490          */
8491         count = iov_iter_count(iter);
8492         if (test_bit(BTRFS_INODE_HAS_ASYNC_EXTENT,
8493                      &BTRFS_I(inode)->runtime_flags))
8494                 filemap_fdatawrite_range(inode->i_mapping, offset,
8495                                          offset + count - 1);
8496
8497         if (iov_iter_rw(iter) == WRITE) {
8498                 /*
8499                  * If the write DIO is beyond the EOF, we need update
8500                  * the isize, but it is protected by i_mutex. So we can
8501                  * not unlock the i_mutex at this case.
8502                  */
8503                 if (offset + count <= inode->i_size) {
8504                         dio_data.overwrite = 1;
8505                         inode_unlock(inode);
8506                         relock = true;
8507                 } else if (iocb->ki_flags & IOCB_NOWAIT) {
8508                         ret = -EAGAIN;
8509                         goto out;
8510                 }
8511                 ret = btrfs_delalloc_reserve_space(inode, &data_reserved,
8512                                                    offset, count);
8513                 if (ret)
8514                         goto out;
8515
8516                 /*
8517                  * We need to know how many extents we reserved so that we can
8518                  * do the accounting properly if we go over the number we
8519                  * originally calculated.  Abuse current->journal_info for this.
8520                  */
8521                 dio_data.reserve = round_up(count,
8522                                             fs_info->sectorsize);
8523                 dio_data.unsubmitted_oe_range_start = (u64)offset;
8524                 dio_data.unsubmitted_oe_range_end = (u64)offset;
8525                 current->journal_info = &dio_data;
8526                 down_read(&BTRFS_I(inode)->dio_sem);
8527         } else if (test_bit(BTRFS_INODE_READDIO_NEED_LOCK,
8528                                      &BTRFS_I(inode)->runtime_flags)) {
8529                 inode_dio_end(inode);
8530                 flags = DIO_LOCKING | DIO_SKIP_HOLES;
8531                 wakeup = false;
8532         }
8533
8534         ret = __blockdev_direct_IO(iocb, inode,
8535                                    fs_info->fs_devices->latest_bdev,
8536                                    iter, btrfs_get_blocks_direct, NULL,
8537                                    btrfs_submit_direct, flags);
8538         if (iov_iter_rw(iter) == WRITE) {
8539                 up_read(&BTRFS_I(inode)->dio_sem);
8540                 current->journal_info = NULL;
8541                 if (ret < 0 && ret != -EIOCBQUEUED) {
8542                         if (dio_data.reserve)
8543                                 btrfs_delalloc_release_space(inode, data_reserved,
8544                                         offset, dio_data.reserve, true);
8545                         /*
8546                          * On error we might have left some ordered extents
8547                          * without submitting corresponding bios for them, so
8548                          * cleanup them up to avoid other tasks getting them
8549                          * and waiting for them to complete forever.
8550                          */
8551                         if (dio_data.unsubmitted_oe_range_start <
8552                             dio_data.unsubmitted_oe_range_end)
8553                                 __endio_write_update_ordered(inode,
8554                                         dio_data.unsubmitted_oe_range_start,
8555                                         dio_data.unsubmitted_oe_range_end -
8556                                         dio_data.unsubmitted_oe_range_start,
8557                                         false);
8558                 } else if (ret >= 0 && (size_t)ret < count)
8559                         btrfs_delalloc_release_space(inode, data_reserved,
8560                                         offset, count - (size_t)ret, true);
8561                 btrfs_delalloc_release_extents(BTRFS_I(inode), count, false);
8562         }
8563 out:
8564         if (wakeup)
8565                 inode_dio_end(inode);
8566         if (relock)
8567                 inode_lock(inode);
8568
8569         extent_changeset_free(data_reserved);
8570         return ret;
8571 }
8572
8573 #define BTRFS_FIEMAP_FLAGS      (FIEMAP_FLAG_SYNC)
8574
8575 static int btrfs_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
8576                 __u64 start, __u64 len)
8577 {
8578         int     ret;
8579
8580         ret = fiemap_check_flags(fieinfo, BTRFS_FIEMAP_FLAGS);
8581         if (ret)
8582                 return ret;
8583
8584         return extent_fiemap(inode, fieinfo, start, len);
8585 }
8586
8587 int btrfs_readpage(struct file *file, struct page *page)
8588 {
8589         struct extent_io_tree *tree;
8590         tree = &BTRFS_I(page->mapping->host)->io_tree;
8591         return extent_read_full_page(tree, page, btrfs_get_extent, 0);
8592 }
8593
8594 static int btrfs_writepage(struct page *page, struct writeback_control *wbc)
8595 {
8596         struct inode *inode = page->mapping->host;
8597         int ret;
8598
8599         if (current->flags & PF_MEMALLOC) {
8600                 redirty_page_for_writepage(wbc, page);
8601                 unlock_page(page);
8602                 return 0;
8603         }
8604
8605         /*
8606          * If we are under memory pressure we will call this directly from the
8607          * VM, we need to make sure we have the inode referenced for the ordered
8608          * extent.  If not just return like we didn't do anything.
8609          */
8610         if (!igrab(inode)) {
8611                 redirty_page_for_writepage(wbc, page);
8612                 return AOP_WRITEPAGE_ACTIVATE;
8613         }
8614         ret = extent_write_full_page(page, wbc);
8615         btrfs_add_delayed_iput(inode);
8616         return ret;
8617 }
8618
8619 static int btrfs_writepages(struct address_space *mapping,
8620                             struct writeback_control *wbc)
8621 {
8622         return extent_writepages(mapping, wbc);
8623 }
8624
8625 static int
8626 btrfs_readpages(struct file *file, struct address_space *mapping,
8627                 struct list_head *pages, unsigned nr_pages)
8628 {
8629         return extent_readpages(mapping, pages, nr_pages);
8630 }
8631
8632 static int __btrfs_releasepage(struct page *page, gfp_t gfp_flags)
8633 {
8634         int ret = try_release_extent_mapping(page, gfp_flags);
8635         if (ret == 1) {
8636                 ClearPagePrivate(page);
8637                 set_page_private(page, 0);
8638                 put_page(page);
8639         }
8640         return ret;
8641 }
8642
8643 static int btrfs_releasepage(struct page *page, gfp_t gfp_flags)
8644 {
8645         if (PageWriteback(page) || PageDirty(page))
8646                 return 0;
8647         return __btrfs_releasepage(page, gfp_flags);
8648 }
8649
8650 static void btrfs_invalidatepage(struct page *page, unsigned int offset,
8651                                  unsigned int length)
8652 {
8653         struct inode *inode = page->mapping->host;
8654         struct extent_io_tree *tree;
8655         struct btrfs_ordered_extent *ordered;
8656         struct extent_state *cached_state = NULL;
8657         u64 page_start = page_offset(page);
8658         u64 page_end = page_start + PAGE_SIZE - 1;
8659         u64 start;
8660         u64 end;
8661         int inode_evicting = inode->i_state & I_FREEING;
8662
8663         /*
8664          * we have the page locked, so new writeback can't start,
8665          * and the dirty bit won't be cleared while we are here.
8666          *
8667          * Wait for IO on this page so that we can safely clear
8668          * the PagePrivate2 bit and do ordered accounting
8669          */
8670         wait_on_page_writeback(page);
8671
8672         tree = &BTRFS_I(inode)->io_tree;
8673         if (offset) {
8674                 btrfs_releasepage(page, GFP_NOFS);
8675                 return;
8676         }
8677
8678         if (!inode_evicting)
8679                 lock_extent_bits(tree, page_start, page_end, &cached_state);
8680 again:
8681         start = page_start;
8682         ordered = btrfs_lookup_ordered_range(BTRFS_I(inode), start,
8683                                         page_end - start + 1);
8684         if (ordered) {
8685                 end = min(page_end, ordered->file_offset + ordered->len - 1);
8686                 /*
8687                  * IO on this page will never be started, so we need
8688                  * to account for any ordered extents now
8689                  */
8690                 if (!inode_evicting)
8691                         clear_extent_bit(tree, start, end,
8692                                          EXTENT_DIRTY | EXTENT_DELALLOC |
8693                                          EXTENT_DELALLOC_NEW |
8694                                          EXTENT_LOCKED | EXTENT_DO_ACCOUNTING |
8695                                          EXTENT_DEFRAG, 1, 0, &cached_state);
8696                 /*
8697                  * whoever cleared the private bit is responsible
8698                  * for the finish_ordered_io
8699                  */
8700                 if (TestClearPagePrivate2(page)) {
8701                         struct btrfs_ordered_inode_tree *tree;
8702                         u64 new_len;
8703
8704                         tree = &BTRFS_I(inode)->ordered_tree;
8705
8706                         spin_lock_irq(&tree->lock);
8707                         set_bit(BTRFS_ORDERED_TRUNCATED, &ordered->flags);
8708                         new_len = start - ordered->file_offset;
8709                         if (new_len < ordered->truncated_len)
8710                                 ordered->truncated_len = new_len;
8711                         spin_unlock_irq(&tree->lock);
8712
8713                         if (btrfs_dec_test_ordered_pending(inode, &ordered,
8714                                                            start,
8715                                                            end - start + 1, 1))
8716                                 btrfs_finish_ordered_io(ordered);
8717                 }
8718                 btrfs_put_ordered_extent(ordered);
8719                 if (!inode_evicting) {
8720                         cached_state = NULL;
8721                         lock_extent_bits(tree, start, end,
8722                                          &cached_state);
8723                 }
8724
8725                 start = end + 1;
8726                 if (start < page_end)
8727                         goto again;
8728         }
8729
8730         /*
8731          * Qgroup reserved space handler
8732          * Page here will be either
8733          * 1) Already written to disk
8734          *    In this case, its reserved space is released from data rsv map
8735          *    and will be freed by delayed_ref handler finally.
8736          *    So even we call qgroup_free_data(), it won't decrease reserved
8737          *    space.
8738          * 2) Not written to disk
8739          *    This means the reserved space should be freed here. However,
8740          *    if a truncate invalidates the page (by clearing PageDirty)
8741          *    and the page is accounted for while allocating extent
8742          *    in btrfs_check_data_free_space() we let delayed_ref to
8743          *    free the entire extent.
8744          */
8745         if (PageDirty(page))
8746                 btrfs_qgroup_free_data(inode, NULL, page_start, PAGE_SIZE);
8747         if (!inode_evicting) {
8748                 clear_extent_bit(tree, page_start, page_end,
8749                                  EXTENT_LOCKED | EXTENT_DIRTY |
8750                                  EXTENT_DELALLOC | EXTENT_DELALLOC_NEW |
8751                                  EXTENT_DO_ACCOUNTING | EXTENT_DEFRAG, 1, 1,
8752                                  &cached_state);
8753
8754                 __btrfs_releasepage(page, GFP_NOFS);
8755         }
8756
8757         ClearPageChecked(page);
8758         if (PagePrivate(page)) {
8759                 ClearPagePrivate(page);
8760                 set_page_private(page, 0);
8761                 put_page(page);
8762         }
8763 }
8764
8765 /*
8766  * btrfs_page_mkwrite() is not allowed to change the file size as it gets
8767  * called from a page fault handler when a page is first dirtied. Hence we must
8768  * be careful to check for EOF conditions here. We set the page up correctly
8769  * for a written page which means we get ENOSPC checking when writing into
8770  * holes and correct delalloc and unwritten extent mapping on filesystems that
8771  * support these features.
8772  *
8773  * We are not allowed to take the i_mutex here so we have to play games to
8774  * protect against truncate races as the page could now be beyond EOF.  Because
8775  * truncate_setsize() writes the inode size before removing pages, once we have
8776  * the page lock we can determine safely if the page is beyond EOF. If it is not
8777  * beyond EOF, then the page is guaranteed safe against truncation until we
8778  * unlock the page.
8779  */
8780 vm_fault_t btrfs_page_mkwrite(struct vm_fault *vmf)
8781 {
8782         struct page *page = vmf->page;
8783         struct inode *inode = file_inode(vmf->vma->vm_file);
8784         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
8785         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
8786         struct btrfs_ordered_extent *ordered;
8787         struct extent_state *cached_state = NULL;
8788         struct extent_changeset *data_reserved = NULL;
8789         char *kaddr;
8790         unsigned long zero_start;
8791         loff_t size;
8792         vm_fault_t ret;
8793         int ret2;
8794         int reserved = 0;
8795         u64 reserved_space;
8796         u64 page_start;
8797         u64 page_end;
8798         u64 end;
8799
8800         reserved_space = PAGE_SIZE;
8801
8802         sb_start_pagefault(inode->i_sb);
8803         page_start = page_offset(page);
8804         page_end = page_start + PAGE_SIZE - 1;
8805         end = page_end;
8806
8807         /*
8808          * Reserving delalloc space after obtaining the page lock can lead to
8809          * deadlock. For example, if a dirty page is locked by this function
8810          * and the call to btrfs_delalloc_reserve_space() ends up triggering
8811          * dirty page write out, then the btrfs_writepage() function could
8812          * end up waiting indefinitely to get a lock on the page currently
8813          * being processed by btrfs_page_mkwrite() function.
8814          */
8815         ret2 = btrfs_delalloc_reserve_space(inode, &data_reserved, page_start,
8816                                            reserved_space);
8817         if (!ret2) {
8818                 ret2 = file_update_time(vmf->vma->vm_file);
8819                 reserved = 1;
8820         }
8821         if (ret2) {
8822                 ret = vmf_error(ret2);
8823                 if (reserved)
8824                         goto out;
8825                 goto out_noreserve;
8826         }
8827
8828         ret = VM_FAULT_NOPAGE; /* make the VM retry the fault */
8829 again:
8830         lock_page(page);
8831         size = i_size_read(inode);
8832
8833         if ((page->mapping != inode->i_mapping) ||
8834             (page_start >= size)) {
8835                 /* page got truncated out from underneath us */
8836                 goto out_unlock;
8837         }
8838         wait_on_page_writeback(page);
8839
8840         lock_extent_bits(io_tree, page_start, page_end, &cached_state);
8841         set_page_extent_mapped(page);
8842
8843         /*
8844          * we can't set the delalloc bits if there are pending ordered
8845          * extents.  Drop our locks and wait for them to finish
8846          */
8847         ordered = btrfs_lookup_ordered_range(BTRFS_I(inode), page_start,
8848                         PAGE_SIZE);
8849         if (ordered) {
8850                 unlock_extent_cached(io_tree, page_start, page_end,
8851                                      &cached_state);
8852                 unlock_page(page);
8853                 btrfs_start_ordered_extent(inode, ordered, 1);
8854                 btrfs_put_ordered_extent(ordered);
8855                 goto again;
8856         }
8857
8858         if (page->index == ((size - 1) >> PAGE_SHIFT)) {
8859                 reserved_space = round_up(size - page_start,
8860                                           fs_info->sectorsize);
8861                 if (reserved_space < PAGE_SIZE) {
8862                         end = page_start + reserved_space - 1;
8863                         btrfs_delalloc_release_space(inode, data_reserved,
8864                                         page_start, PAGE_SIZE - reserved_space,
8865                                         true);
8866                 }
8867         }
8868
8869         /*
8870          * page_mkwrite gets called when the page is firstly dirtied after it's
8871          * faulted in, but write(2) could also dirty a page and set delalloc
8872          * bits, thus in this case for space account reason, we still need to
8873          * clear any delalloc bits within this page range since we have to
8874          * reserve data&meta space before lock_page() (see above comments).
8875          */
8876         clear_extent_bit(&BTRFS_I(inode)->io_tree, page_start, end,
8877                           EXTENT_DIRTY | EXTENT_DELALLOC |
8878                           EXTENT_DO_ACCOUNTING | EXTENT_DEFRAG,
8879                           0, 0, &cached_state);
8880
8881         ret2 = btrfs_set_extent_delalloc(inode, page_start, end, 0,
8882                                         &cached_state, 0);
8883         if (ret2) {
8884                 unlock_extent_cached(io_tree, page_start, page_end,
8885                                      &cached_state);
8886                 ret = VM_FAULT_SIGBUS;
8887                 goto out_unlock;
8888         }
8889         ret2 = 0;
8890
8891         /* page is wholly or partially inside EOF */
8892         if (page_start + PAGE_SIZE > size)
8893                 zero_start = size & ~PAGE_MASK;
8894         else
8895                 zero_start = PAGE_SIZE;
8896
8897         if (zero_start != PAGE_SIZE) {
8898                 kaddr = kmap(page);
8899                 memset(kaddr + zero_start, 0, PAGE_SIZE - zero_start);
8900                 flush_dcache_page(page);
8901                 kunmap(page);
8902         }
8903         ClearPageChecked(page);
8904         set_page_dirty(page);
8905         SetPageUptodate(page);
8906
8907         BTRFS_I(inode)->last_trans = fs_info->generation;
8908         BTRFS_I(inode)->last_sub_trans = BTRFS_I(inode)->root->log_transid;
8909         BTRFS_I(inode)->last_log_commit = BTRFS_I(inode)->root->last_log_commit;
8910
8911         unlock_extent_cached(io_tree, page_start, page_end, &cached_state);
8912
8913         if (!ret2) {
8914                 btrfs_delalloc_release_extents(BTRFS_I(inode), PAGE_SIZE, true);
8915                 sb_end_pagefault(inode->i_sb);
8916                 extent_changeset_free(data_reserved);
8917                 return VM_FAULT_LOCKED;
8918         }
8919
8920 out_unlock:
8921         unlock_page(page);
8922 out:
8923         btrfs_delalloc_release_extents(BTRFS_I(inode), PAGE_SIZE, (ret != 0));
8924         btrfs_delalloc_release_space(inode, data_reserved, page_start,
8925                                      reserved_space, (ret != 0));
8926 out_noreserve:
8927         sb_end_pagefault(inode->i_sb);
8928         extent_changeset_free(data_reserved);
8929         return ret;
8930 }
8931
8932 static int btrfs_truncate(struct inode *inode, bool skip_writeback)
8933 {
8934         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
8935         struct btrfs_root *root = BTRFS_I(inode)->root;
8936         struct btrfs_block_rsv *rsv;
8937         int ret;
8938         struct btrfs_trans_handle *trans;
8939         u64 mask = fs_info->sectorsize - 1;
8940         u64 min_size = btrfs_calc_trunc_metadata_size(fs_info, 1);
8941
8942         if (!skip_writeback) {
8943                 ret = btrfs_wait_ordered_range(inode, inode->i_size & (~mask),
8944                                                (u64)-1);
8945                 if (ret)
8946                         return ret;
8947         }
8948
8949         /*
8950          * Yes ladies and gentlemen, this is indeed ugly.  We have a couple of
8951          * things going on here:
8952          *
8953          * 1) We need to reserve space to update our inode.
8954          *
8955          * 2) We need to have something to cache all the space that is going to
8956          * be free'd up by the truncate operation, but also have some slack
8957          * space reserved in case it uses space during the truncate (thank you
8958          * very much snapshotting).
8959          *
8960          * And we need these to be separate.  The fact is we can use a lot of
8961          * space doing the truncate, and we have no earthly idea how much space
8962          * we will use, so we need the truncate reservation to be separate so it
8963          * doesn't end up using space reserved for updating the inode.  We also
8964          * need to be able to stop the transaction and start a new one, which
8965          * means we need to be able to update the inode several times, and we
8966          * have no idea of knowing how many times that will be, so we can't just
8967          * reserve 1 item for the entirety of the operation, so that has to be
8968          * done separately as well.
8969          *
8970          * So that leaves us with
8971          *
8972          * 1) rsv - for the truncate reservation, which we will steal from the
8973          * transaction reservation.
8974          * 2) fs_info->trans_block_rsv - this will have 1 items worth left for
8975          * updating the inode.
8976          */
8977         rsv = btrfs_alloc_block_rsv(fs_info, BTRFS_BLOCK_RSV_TEMP);
8978         if (!rsv)
8979                 return -ENOMEM;
8980         rsv->size = min_size;
8981         rsv->failfast = 1;
8982
8983         /*
8984          * 1 for the truncate slack space
8985          * 1 for updating the inode.
8986          */
8987         trans = btrfs_start_transaction(root, 2);
8988         if (IS_ERR(trans)) {
8989                 ret = PTR_ERR(trans);
8990                 goto out;
8991         }
8992
8993         /* Migrate the slack space for the truncate to our reserve */
8994         ret = btrfs_block_rsv_migrate(&fs_info->trans_block_rsv, rsv,
8995                                       min_size, false);
8996         BUG_ON(ret);
8997
8998         /*
8999          * So if we truncate and then write and fsync we normally would just
9000          * write the extents that changed, which is a problem if we need to
9001          * first truncate that entire inode.  So set this flag so we write out
9002          * all of the extents in the inode to the sync log so we're completely
9003          * safe.
9004          */
9005         set_bit(BTRFS_INODE_NEEDS_FULL_SYNC, &BTRFS_I(inode)->runtime_flags);
9006         trans->block_rsv = rsv;
9007
9008         while (1) {
9009                 ret = btrfs_truncate_inode_items(trans, root, inode,
9010                                                  inode->i_size,
9011                                                  BTRFS_EXTENT_DATA_KEY);
9012                 trans->block_rsv = &fs_info->trans_block_rsv;
9013                 if (ret != -ENOSPC && ret != -EAGAIN)
9014                         break;
9015
9016                 ret = btrfs_update_inode(trans, root, inode);
9017                 if (ret)
9018                         break;
9019
9020                 btrfs_end_transaction(trans);
9021                 btrfs_btree_balance_dirty(fs_info);
9022
9023                 trans = btrfs_start_transaction(root, 2);
9024                 if (IS_ERR(trans)) {
9025                         ret = PTR_ERR(trans);
9026                         trans = NULL;
9027                         break;
9028                 }
9029
9030                 btrfs_block_rsv_release(fs_info, rsv, -1);
9031                 ret = btrfs_block_rsv_migrate(&fs_info->trans_block_rsv,
9032                                               rsv, min_size, false);
9033                 BUG_ON(ret);    /* shouldn't happen */
9034                 trans->block_rsv = rsv;
9035         }
9036
9037         /*
9038          * We can't call btrfs_truncate_block inside a trans handle as we could
9039          * deadlock with freeze, if we got NEED_TRUNCATE_BLOCK then we know
9040          * we've truncated everything except the last little bit, and can do
9041          * btrfs_truncate_block and then update the disk_i_size.
9042          */
9043         if (ret == NEED_TRUNCATE_BLOCK) {
9044                 btrfs_end_transaction(trans);
9045                 btrfs_btree_balance_dirty(fs_info);
9046
9047                 ret = btrfs_truncate_block(inode, inode->i_size, 0, 0);
9048                 if (ret)
9049                         goto out;
9050                 trans = btrfs_start_transaction(root, 1);
9051                 if (IS_ERR(trans)) {
9052                         ret = PTR_ERR(trans);
9053                         goto out;
9054                 }
9055                 btrfs_ordered_update_i_size(inode, inode->i_size, NULL);
9056         }
9057
9058         if (trans) {
9059                 int ret2;
9060
9061                 trans->block_rsv = &fs_info->trans_block_rsv;
9062                 ret2 = btrfs_update_inode(trans, root, inode);
9063                 if (ret2 && !ret)
9064                         ret = ret2;
9065
9066                 ret2 = btrfs_end_transaction(trans);
9067                 if (ret2 && !ret)
9068                         ret = ret2;
9069                 btrfs_btree_balance_dirty(fs_info);
9070         }
9071 out:
9072         btrfs_free_block_rsv(fs_info, rsv);
9073
9074         return ret;
9075 }
9076
9077 /*
9078  * create a new subvolume directory/inode (helper for the ioctl).
9079  */
9080 int btrfs_create_subvol_root(struct btrfs_trans_handle *trans,
9081                              struct btrfs_root *new_root,
9082                              struct btrfs_root *parent_root,
9083                              u64 new_dirid)
9084 {
9085         struct inode *inode;
9086         int err;
9087         u64 index = 0;
9088
9089         inode = btrfs_new_inode(trans, new_root, NULL, "..", 2,
9090                                 new_dirid, new_dirid,
9091                                 S_IFDIR | (~current_umask() & S_IRWXUGO),
9092                                 &index);
9093         if (IS_ERR(inode))
9094                 return PTR_ERR(inode);
9095         inode->i_op = &btrfs_dir_inode_operations;
9096         inode->i_fop = &btrfs_dir_file_operations;
9097
9098         set_nlink(inode, 1);
9099         btrfs_i_size_write(BTRFS_I(inode), 0);
9100         unlock_new_inode(inode);
9101
9102         err = btrfs_subvol_inherit_props(trans, new_root, parent_root);
9103         if (err)
9104                 btrfs_err(new_root->fs_info,
9105                           "error inheriting subvolume %llu properties: %d",
9106                           new_root->root_key.objectid, err);
9107
9108         err = btrfs_update_inode(trans, new_root, inode);
9109
9110         iput(inode);
9111         return err;
9112 }
9113
9114 struct inode *btrfs_alloc_inode(struct super_block *sb)
9115 {
9116         struct btrfs_fs_info *fs_info = btrfs_sb(sb);
9117         struct btrfs_inode *ei;
9118         struct inode *inode;
9119
9120         ei = kmem_cache_alloc(btrfs_inode_cachep, GFP_KERNEL);
9121         if (!ei)
9122                 return NULL;
9123
9124         ei->root = NULL;
9125         ei->generation = 0;
9126         ei->last_trans = 0;
9127         ei->last_sub_trans = 0;
9128         ei->logged_trans = 0;
9129         ei->delalloc_bytes = 0;
9130         ei->new_delalloc_bytes = 0;
9131         ei->defrag_bytes = 0;
9132         ei->disk_i_size = 0;
9133         ei->flags = 0;
9134         ei->csum_bytes = 0;
9135         ei->index_cnt = (u64)-1;
9136         ei->dir_index = 0;
9137         ei->last_unlink_trans = 0;
9138         ei->last_log_commit = 0;
9139
9140         spin_lock_init(&ei->lock);
9141         ei->outstanding_extents = 0;
9142         if (sb->s_magic != BTRFS_TEST_MAGIC)
9143                 btrfs_init_metadata_block_rsv(fs_info, &ei->block_rsv,
9144                                               BTRFS_BLOCK_RSV_DELALLOC);
9145         ei->runtime_flags = 0;
9146         ei->prop_compress = BTRFS_COMPRESS_NONE;
9147         ei->defrag_compress = BTRFS_COMPRESS_NONE;
9148
9149         ei->delayed_node = NULL;
9150
9151         ei->i_otime.tv_sec = 0;
9152         ei->i_otime.tv_nsec = 0;
9153
9154         inode = &ei->vfs_inode;
9155         extent_map_tree_init(&ei->extent_tree);
9156         extent_io_tree_init(&ei->io_tree, inode);
9157         extent_io_tree_init(&ei->io_failure_tree, inode);
9158         ei->io_tree.track_uptodate = 1;
9159         ei->io_failure_tree.track_uptodate = 1;
9160         atomic_set(&ei->sync_writers, 0);
9161         mutex_init(&ei->log_mutex);
9162         mutex_init(&ei->delalloc_mutex);
9163         btrfs_ordered_inode_tree_init(&ei->ordered_tree);
9164         INIT_LIST_HEAD(&ei->delalloc_inodes);
9165         INIT_LIST_HEAD(&ei->delayed_iput);
9166         RB_CLEAR_NODE(&ei->rb_node);
9167         init_rwsem(&ei->dio_sem);
9168
9169         return inode;
9170 }
9171
9172 #ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
9173 void btrfs_test_destroy_inode(struct inode *inode)
9174 {
9175         btrfs_drop_extent_cache(BTRFS_I(inode), 0, (u64)-1, 0);
9176         kmem_cache_free(btrfs_inode_cachep, BTRFS_I(inode));
9177 }
9178 #endif
9179
9180 static void btrfs_i_callback(struct rcu_head *head)
9181 {
9182         struct inode *inode = container_of(head, struct inode, i_rcu);
9183         kmem_cache_free(btrfs_inode_cachep, BTRFS_I(inode));
9184 }
9185
9186 void btrfs_destroy_inode(struct inode *inode)
9187 {
9188         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
9189         struct btrfs_ordered_extent *ordered;
9190         struct btrfs_root *root = BTRFS_I(inode)->root;
9191
9192         WARN_ON(!hlist_empty(&inode->i_dentry));
9193         WARN_ON(inode->i_data.nrpages);
9194         WARN_ON(BTRFS_I(inode)->block_rsv.reserved);
9195         WARN_ON(BTRFS_I(inode)->block_rsv.size);
9196         WARN_ON(BTRFS_I(inode)->outstanding_extents);
9197         WARN_ON(BTRFS_I(inode)->delalloc_bytes);
9198         WARN_ON(BTRFS_I(inode)->new_delalloc_bytes);
9199         WARN_ON(BTRFS_I(inode)->csum_bytes);
9200         WARN_ON(BTRFS_I(inode)->defrag_bytes);
9201
9202         /*
9203          * This can happen where we create an inode, but somebody else also
9204          * created the same inode and we need to destroy the one we already
9205          * created.
9206          */
9207         if (!root)
9208                 goto free;
9209
9210         while (1) {
9211                 ordered = btrfs_lookup_first_ordered_extent(inode, (u64)-1);
9212                 if (!ordered)
9213                         break;
9214                 else {
9215                         btrfs_err(fs_info,
9216                                   "found ordered extent %llu %llu on inode cleanup",
9217                                   ordered->file_offset, ordered->len);
9218                         btrfs_remove_ordered_extent(inode, ordered);
9219                         btrfs_put_ordered_extent(ordered);
9220                         btrfs_put_ordered_extent(ordered);
9221                 }
9222         }
9223         btrfs_qgroup_check_reserved_leak(inode);
9224         inode_tree_del(inode);
9225         btrfs_drop_extent_cache(BTRFS_I(inode), 0, (u64)-1, 0);
9226 free:
9227         call_rcu(&inode->i_rcu, btrfs_i_callback);
9228 }
9229
9230 int btrfs_drop_inode(struct inode *inode)
9231 {
9232         struct btrfs_root *root = BTRFS_I(inode)->root;
9233
9234         if (root == NULL)
9235                 return 1;
9236
9237         /* the snap/subvol tree is on deleting */
9238         if (btrfs_root_refs(&root->root_item) == 0)
9239                 return 1;
9240         else
9241                 return generic_drop_inode(inode);
9242 }
9243
9244 static void init_once(void *foo)
9245 {
9246         struct btrfs_inode *ei = (struct btrfs_inode *) foo;
9247
9248         inode_init_once(&ei->vfs_inode);
9249 }
9250
9251 void __cold btrfs_destroy_cachep(void)
9252 {
9253         /*
9254          * Make sure all delayed rcu free inodes are flushed before we
9255          * destroy cache.
9256          */
9257         rcu_barrier();
9258         kmem_cache_destroy(btrfs_inode_cachep);
9259         kmem_cache_destroy(btrfs_trans_handle_cachep);
9260         kmem_cache_destroy(btrfs_path_cachep);
9261         kmem_cache_destroy(btrfs_free_space_cachep);
9262 }
9263
9264 int __init btrfs_init_cachep(void)
9265 {
9266         btrfs_inode_cachep = kmem_cache_create("btrfs_inode",
9267                         sizeof(struct btrfs_inode), 0,
9268                         SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD | SLAB_ACCOUNT,
9269                         init_once);
9270         if (!btrfs_inode_cachep)
9271                 goto fail;
9272
9273         btrfs_trans_handle_cachep = kmem_cache_create("btrfs_trans_handle",
9274                         sizeof(struct btrfs_trans_handle), 0,
9275                         SLAB_TEMPORARY | SLAB_MEM_SPREAD, NULL);
9276         if (!btrfs_trans_handle_cachep)
9277                 goto fail;
9278
9279         btrfs_path_cachep = kmem_cache_create("btrfs_path",
9280                         sizeof(struct btrfs_path), 0,
9281                         SLAB_MEM_SPREAD, NULL);
9282         if (!btrfs_path_cachep)
9283                 goto fail;
9284
9285         btrfs_free_space_cachep = kmem_cache_create("btrfs_free_space",
9286                         sizeof(struct btrfs_free_space), 0,
9287                         SLAB_MEM_SPREAD, NULL);
9288         if (!btrfs_free_space_cachep)
9289                 goto fail;
9290
9291         return 0;
9292 fail:
9293         btrfs_destroy_cachep();
9294         return -ENOMEM;
9295 }
9296
9297 static int btrfs_getattr(const struct path *path, struct kstat *stat,
9298                          u32 request_mask, unsigned int flags)
9299 {
9300         u64 delalloc_bytes;
9301         struct inode *inode = d_inode(path->dentry);
9302         u32 blocksize = inode->i_sb->s_blocksize;
9303         u32 bi_flags = BTRFS_I(inode)->flags;
9304
9305         stat->result_mask |= STATX_BTIME;
9306         stat->btime.tv_sec = BTRFS_I(inode)->i_otime.tv_sec;
9307         stat->btime.tv_nsec = BTRFS_I(inode)->i_otime.tv_nsec;
9308         if (bi_flags & BTRFS_INODE_APPEND)
9309                 stat->attributes |= STATX_ATTR_APPEND;
9310         if (bi_flags & BTRFS_INODE_COMPRESS)
9311                 stat->attributes |= STATX_ATTR_COMPRESSED;
9312         if (bi_flags & BTRFS_INODE_IMMUTABLE)
9313                 stat->attributes |= STATX_ATTR_IMMUTABLE;
9314         if (bi_flags & BTRFS_INODE_NODUMP)
9315                 stat->attributes |= STATX_ATTR_NODUMP;
9316
9317         stat->attributes_mask |= (STATX_ATTR_APPEND |
9318                                   STATX_ATTR_COMPRESSED |
9319                                   STATX_ATTR_IMMUTABLE |
9320                                   STATX_ATTR_NODUMP);
9321
9322         generic_fillattr(inode, stat);
9323         stat->dev = BTRFS_I(inode)->root->anon_dev;
9324
9325         spin_lock(&BTRFS_I(inode)->lock);
9326         delalloc_bytes = BTRFS_I(inode)->new_delalloc_bytes;
9327         spin_unlock(&BTRFS_I(inode)->lock);
9328         stat->blocks = (ALIGN(inode_get_bytes(inode), blocksize) +
9329                         ALIGN(delalloc_bytes, blocksize)) >> 9;
9330         return 0;
9331 }
9332
9333 static int btrfs_rename_exchange(struct inode *old_dir,
9334                               struct dentry *old_dentry,
9335                               struct inode *new_dir,
9336                               struct dentry *new_dentry)
9337 {
9338         struct btrfs_fs_info *fs_info = btrfs_sb(old_dir->i_sb);
9339         struct btrfs_trans_handle *trans;
9340         struct btrfs_root *root = BTRFS_I(old_dir)->root;
9341         struct btrfs_root *dest = BTRFS_I(new_dir)->root;
9342         struct inode *new_inode = new_dentry->d_inode;
9343         struct inode *old_inode = old_dentry->d_inode;
9344         struct timespec64 ctime = current_time(old_inode);
9345         struct dentry *parent;
9346         u64 old_ino = btrfs_ino(BTRFS_I(old_inode));
9347         u64 new_ino = btrfs_ino(BTRFS_I(new_inode));
9348         u64 old_idx = 0;
9349         u64 new_idx = 0;
9350         u64 root_objectid;
9351         int ret;
9352         bool root_log_pinned = false;
9353         bool dest_log_pinned = false;
9354         struct btrfs_log_ctx ctx_root;
9355         struct btrfs_log_ctx ctx_dest;
9356         bool sync_log_root = false;
9357         bool sync_log_dest = false;
9358         bool commit_transaction = false;
9359
9360         /* we only allow rename subvolume link between subvolumes */
9361         if (old_ino != BTRFS_FIRST_FREE_OBJECTID && root != dest)
9362                 return -EXDEV;
9363
9364         btrfs_init_log_ctx(&ctx_root, old_inode);
9365         btrfs_init_log_ctx(&ctx_dest, new_inode);
9366
9367         /* close the race window with snapshot create/destroy ioctl */
9368         if (old_ino == BTRFS_FIRST_FREE_OBJECTID)
9369                 down_read(&fs_info->subvol_sem);
9370         if (new_ino == BTRFS_FIRST_FREE_OBJECTID)
9371                 down_read(&fs_info->subvol_sem);
9372
9373         /*
9374          * We want to reserve the absolute worst case amount of items.  So if
9375          * both inodes are subvols and we need to unlink them then that would
9376          * require 4 item modifications, but if they are both normal inodes it
9377          * would require 5 item modifications, so we'll assume their normal
9378          * inodes.  So 5 * 2 is 10, plus 2 for the new links, so 12 total items
9379          * should cover the worst case number of items we'll modify.
9380          */
9381         trans = btrfs_start_transaction(root, 12);
9382         if (IS_ERR(trans)) {
9383                 ret = PTR_ERR(trans);
9384                 goto out_notrans;
9385         }
9386
9387         /*
9388          * We need to find a free sequence number both in the source and
9389          * in the destination directory for the exchange.
9390          */
9391         ret = btrfs_set_inode_index(BTRFS_I(new_dir), &old_idx);
9392         if (ret)
9393                 goto out_fail;
9394         ret = btrfs_set_inode_index(BTRFS_I(old_dir), &new_idx);
9395         if (ret)
9396                 goto out_fail;
9397
9398         BTRFS_I(old_inode)->dir_index = 0ULL;
9399         BTRFS_I(new_inode)->dir_index = 0ULL;
9400
9401         /* Reference for the source. */
9402         if (old_ino == BTRFS_FIRST_FREE_OBJECTID) {
9403                 /* force full log commit if subvolume involved. */
9404                 btrfs_set_log_full_commit(fs_info, trans);
9405         } else {
9406                 btrfs_pin_log_trans(root);
9407                 root_log_pinned = true;
9408                 ret = btrfs_insert_inode_ref(trans, dest,
9409                                              new_dentry->d_name.name,
9410                                              new_dentry->d_name.len,
9411                                              old_ino,
9412                                              btrfs_ino(BTRFS_I(new_dir)),
9413                                              old_idx);
9414                 if (ret)
9415                         goto out_fail;
9416         }
9417
9418         /* And now for the dest. */
9419         if (new_ino == BTRFS_FIRST_FREE_OBJECTID) {
9420                 /* force full log commit if subvolume involved. */
9421                 btrfs_set_log_full_commit(fs_info, trans);
9422         } else {
9423                 btrfs_pin_log_trans(dest);
9424                 dest_log_pinned = true;
9425                 ret = btrfs_insert_inode_ref(trans, root,
9426                                              old_dentry->d_name.name,
9427                                              old_dentry->d_name.len,
9428                                              new_ino,
9429                                              btrfs_ino(BTRFS_I(old_dir)),
9430                                              new_idx);
9431                 if (ret)
9432                         goto out_fail;
9433         }
9434
9435         /* Update inode version and ctime/mtime. */
9436         inode_inc_iversion(old_dir);
9437         inode_inc_iversion(new_dir);
9438         inode_inc_iversion(old_inode);
9439         inode_inc_iversion(new_inode);
9440         old_dir->i_ctime = old_dir->i_mtime = ctime;
9441         new_dir->i_ctime = new_dir->i_mtime = ctime;
9442         old_inode->i_ctime = ctime;
9443         new_inode->i_ctime = ctime;
9444
9445         if (old_dentry->d_parent != new_dentry->d_parent) {
9446                 btrfs_record_unlink_dir(trans, BTRFS_I(old_dir),
9447                                 BTRFS_I(old_inode), 1);
9448                 btrfs_record_unlink_dir(trans, BTRFS_I(new_dir),
9449                                 BTRFS_I(new_inode), 1);
9450         }
9451
9452         /* src is a subvolume */
9453         if (old_ino == BTRFS_FIRST_FREE_OBJECTID) {
9454                 root_objectid = BTRFS_I(old_inode)->root->root_key.objectid;
9455                 ret = btrfs_unlink_subvol(trans, old_dir, root_objectid,
9456                                           old_dentry->d_name.name,
9457                                           old_dentry->d_name.len);
9458         } else { /* src is an inode */
9459                 ret = __btrfs_unlink_inode(trans, root, BTRFS_I(old_dir),
9460                                            BTRFS_I(old_dentry->d_inode),
9461                                            old_dentry->d_name.name,
9462                                            old_dentry->d_name.len);
9463                 if (!ret)
9464                         ret = btrfs_update_inode(trans, root, old_inode);
9465         }
9466         if (ret) {
9467                 btrfs_abort_transaction(trans, ret);
9468                 goto out_fail;
9469         }
9470
9471         /* dest is a subvolume */
9472         if (new_ino == BTRFS_FIRST_FREE_OBJECTID) {
9473                 root_objectid = BTRFS_I(new_inode)->root->root_key.objectid;
9474                 ret = btrfs_unlink_subvol(trans, new_dir, root_objectid,
9475                                           new_dentry->d_name.name,
9476                                           new_dentry->d_name.len);
9477         } else { /* dest is an inode */
9478                 ret = __btrfs_unlink_inode(trans, dest, BTRFS_I(new_dir),
9479                                            BTRFS_I(new_dentry->d_inode),
9480                                            new_dentry->d_name.name,
9481                                            new_dentry->d_name.len);
9482                 if (!ret)
9483                         ret = btrfs_update_inode(trans, dest, new_inode);
9484         }
9485         if (ret) {
9486                 btrfs_abort_transaction(trans, ret);
9487                 goto out_fail;
9488         }
9489
9490         ret = btrfs_add_link(trans, BTRFS_I(new_dir), BTRFS_I(old_inode),
9491                              new_dentry->d_name.name,
9492                              new_dentry->d_name.len, 0, old_idx);
9493         if (ret) {
9494                 btrfs_abort_transaction(trans, ret);
9495                 goto out_fail;
9496         }
9497
9498         ret = btrfs_add_link(trans, BTRFS_I(old_dir), BTRFS_I(new_inode),
9499                              old_dentry->d_name.name,
9500                              old_dentry->d_name.len, 0, new_idx);
9501         if (ret) {
9502                 btrfs_abort_transaction(trans, ret);
9503                 goto out_fail;
9504         }
9505
9506         if (old_inode->i_nlink == 1)
9507                 BTRFS_I(old_inode)->dir_index = old_idx;
9508         if (new_inode->i_nlink == 1)
9509                 BTRFS_I(new_inode)->dir_index = new_idx;
9510
9511         if (root_log_pinned) {
9512                 parent = new_dentry->d_parent;
9513                 ret = btrfs_log_new_name(trans, BTRFS_I(old_inode),
9514                                          BTRFS_I(old_dir), parent,
9515                                          false, &ctx_root);
9516                 if (ret == BTRFS_NEED_LOG_SYNC)
9517                         sync_log_root = true;
9518                 else if (ret == BTRFS_NEED_TRANS_COMMIT)
9519                         commit_transaction = true;
9520                 ret = 0;
9521                 btrfs_end_log_trans(root);
9522                 root_log_pinned = false;
9523         }
9524         if (dest_log_pinned) {
9525                 if (!commit_transaction) {
9526                         parent = old_dentry->d_parent;
9527                         ret = btrfs_log_new_name(trans, BTRFS_I(new_inode),
9528                                                  BTRFS_I(new_dir), parent,
9529                                                  false, &ctx_dest);
9530                         if (ret == BTRFS_NEED_LOG_SYNC)
9531                                 sync_log_dest = true;
9532                         else if (ret == BTRFS_NEED_TRANS_COMMIT)
9533                                 commit_transaction = true;
9534                         ret = 0;
9535                 }
9536                 btrfs_end_log_trans(dest);
9537                 dest_log_pinned = false;
9538         }
9539 out_fail:
9540         /*
9541          * If we have pinned a log and an error happened, we unpin tasks
9542          * trying to sync the log and force them to fallback to a transaction
9543          * commit if the log currently contains any of the inodes involved in
9544          * this rename operation (to ensure we do not persist a log with an
9545          * inconsistent state for any of these inodes or leading to any
9546          * inconsistencies when replayed). If the transaction was aborted, the
9547          * abortion reason is propagated to userspace when attempting to commit
9548          * the transaction. If the log does not contain any of these inodes, we
9549          * allow the tasks to sync it.
9550          */
9551         if (ret && (root_log_pinned || dest_log_pinned)) {
9552                 if (btrfs_inode_in_log(BTRFS_I(old_dir), fs_info->generation) ||
9553                     btrfs_inode_in_log(BTRFS_I(new_dir), fs_info->generation) ||
9554                     btrfs_inode_in_log(BTRFS_I(old_inode), fs_info->generation) ||
9555                     (new_inode &&
9556                      btrfs_inode_in_log(BTRFS_I(new_inode), fs_info->generation)))
9557                         btrfs_set_log_full_commit(fs_info, trans);
9558
9559                 if (root_log_pinned) {
9560                         btrfs_end_log_trans(root);
9561                         root_log_pinned = false;
9562                 }
9563                 if (dest_log_pinned) {
9564                         btrfs_end_log_trans(dest);
9565                         dest_log_pinned = false;
9566                 }
9567         }
9568         if (!ret && sync_log_root && !commit_transaction) {
9569                 ret = btrfs_sync_log(trans, BTRFS_I(old_inode)->root,
9570                                      &ctx_root);
9571                 if (ret)
9572                         commit_transaction = true;
9573         }
9574         if (!ret && sync_log_dest && !commit_transaction) {
9575                 ret = btrfs_sync_log(trans, BTRFS_I(new_inode)->root,
9576                                      &ctx_dest);
9577                 if (ret)
9578                         commit_transaction = true;
9579         }
9580         if (commit_transaction) {
9581                 ret = btrfs_commit_transaction(trans);
9582         } else {
9583                 int ret2;
9584
9585                 ret2 = btrfs_end_transaction(trans);
9586                 ret = ret ? ret : ret2;
9587         }
9588 out_notrans:
9589         if (new_ino == BTRFS_FIRST_FREE_OBJECTID)
9590                 up_read(&fs_info->subvol_sem);
9591         if (old_ino == BTRFS_FIRST_FREE_OBJECTID)
9592                 up_read(&fs_info->subvol_sem);
9593
9594         return ret;
9595 }
9596
9597 static int btrfs_whiteout_for_rename(struct btrfs_trans_handle *trans,
9598                                      struct btrfs_root *root,
9599                                      struct inode *dir,
9600                                      struct dentry *dentry)
9601 {
9602         int ret;
9603         struct inode *inode;
9604         u64 objectid;
9605         u64 index;
9606
9607         ret = btrfs_find_free_ino(root, &objectid);
9608         if (ret)
9609                 return ret;
9610
9611         inode = btrfs_new_inode(trans, root, dir,
9612                                 dentry->d_name.name,
9613                                 dentry->d_name.len,
9614                                 btrfs_ino(BTRFS_I(dir)),
9615                                 objectid,
9616                                 S_IFCHR | WHITEOUT_MODE,
9617                                 &index);
9618
9619         if (IS_ERR(inode)) {
9620                 ret = PTR_ERR(inode);
9621                 return ret;
9622         }
9623
9624         inode->i_op = &btrfs_special_inode_operations;
9625         init_special_inode(inode, inode->i_mode,
9626                 WHITEOUT_DEV);
9627
9628         ret = btrfs_init_inode_security(trans, inode, dir,
9629                                 &dentry->d_name);
9630         if (ret)
9631                 goto out;
9632
9633         ret = btrfs_add_nondir(trans, BTRFS_I(dir), dentry,
9634                                 BTRFS_I(inode), 0, index);
9635         if (ret)
9636                 goto out;
9637
9638         ret = btrfs_update_inode(trans, root, inode);
9639 out:
9640         unlock_new_inode(inode);
9641         if (ret)
9642                 inode_dec_link_count(inode);
9643         iput(inode);
9644
9645         return ret;
9646 }
9647
9648 static int btrfs_rename(struct inode *old_dir, struct dentry *old_dentry,
9649                            struct inode *new_dir, struct dentry *new_dentry,
9650                            unsigned int flags)
9651 {
9652         struct btrfs_fs_info *fs_info = btrfs_sb(old_dir->i_sb);
9653         struct btrfs_trans_handle *trans;
9654         unsigned int trans_num_items;
9655         struct btrfs_root *root = BTRFS_I(old_dir)->root;
9656         struct btrfs_root *dest = BTRFS_I(new_dir)->root;
9657         struct inode *new_inode = d_inode(new_dentry);
9658         struct inode *old_inode = d_inode(old_dentry);
9659         u64 index = 0;
9660         u64 root_objectid;
9661         int ret;
9662         u64 old_ino = btrfs_ino(BTRFS_I(old_inode));
9663         bool log_pinned = false;
9664         struct btrfs_log_ctx ctx;
9665         bool sync_log = false;
9666         bool commit_transaction = false;
9667
9668         if (btrfs_ino(BTRFS_I(new_dir)) == BTRFS_EMPTY_SUBVOL_DIR_OBJECTID)
9669                 return -EPERM;
9670
9671         /* we only allow rename subvolume link between subvolumes */
9672         if (old_ino != BTRFS_FIRST_FREE_OBJECTID && root != dest)
9673                 return -EXDEV;
9674
9675         if (old_ino == BTRFS_EMPTY_SUBVOL_DIR_OBJECTID ||
9676             (new_inode && btrfs_ino(BTRFS_I(new_inode)) == BTRFS_FIRST_FREE_OBJECTID))
9677                 return -ENOTEMPTY;
9678
9679         if (S_ISDIR(old_inode->i_mode) && new_inode &&
9680             new_inode->i_size > BTRFS_EMPTY_DIR_SIZE)
9681                 return -ENOTEMPTY;
9682
9683
9684         /* check for collisions, even if the  name isn't there */
9685         ret = btrfs_check_dir_item_collision(dest, new_dir->i_ino,
9686                              new_dentry->d_name.name,
9687                              new_dentry->d_name.len);
9688
9689         if (ret) {
9690                 if (ret == -EEXIST) {
9691                         /* we shouldn't get
9692                          * eexist without a new_inode */
9693                         if (WARN_ON(!new_inode)) {
9694                                 return ret;
9695                         }
9696                 } else {
9697                         /* maybe -EOVERFLOW */
9698                         return ret;
9699                 }
9700         }
9701         ret = 0;
9702
9703         /*
9704          * we're using rename to replace one file with another.  Start IO on it
9705          * now so  we don't add too much work to the end of the transaction
9706          */
9707         if (new_inode && S_ISREG(old_inode->i_mode) && new_inode->i_size)
9708                 filemap_flush(old_inode->i_mapping);
9709
9710         /* close the racy window with snapshot create/destroy ioctl */
9711         if (old_ino == BTRFS_FIRST_FREE_OBJECTID)
9712                 down_read(&fs_info->subvol_sem);
9713         /*
9714          * We want to reserve the absolute worst case amount of items.  So if
9715          * both inodes are subvols and we need to unlink them then that would
9716          * require 4 item modifications, but if they are both normal inodes it
9717          * would require 5 item modifications, so we'll assume they are normal
9718          * inodes.  So 5 * 2 is 10, plus 1 for the new link, so 11 total items
9719          * should cover the worst case number of items we'll modify.
9720          * If our rename has the whiteout flag, we need more 5 units for the
9721          * new inode (1 inode item, 1 inode ref, 2 dir items and 1 xattr item
9722          * when selinux is enabled).
9723          */
9724         trans_num_items = 11;
9725         if (flags & RENAME_WHITEOUT)
9726                 trans_num_items += 5;
9727         trans = btrfs_start_transaction(root, trans_num_items);
9728         if (IS_ERR(trans)) {
9729                 ret = PTR_ERR(trans);
9730                 goto out_notrans;
9731         }
9732
9733         if (dest != root)
9734                 btrfs_record_root_in_trans(trans, dest);
9735
9736         ret = btrfs_set_inode_index(BTRFS_I(new_dir), &index);
9737         if (ret)
9738                 goto out_fail;
9739
9740         BTRFS_I(old_inode)->dir_index = 0ULL;
9741         if (unlikely(old_ino == BTRFS_FIRST_FREE_OBJECTID)) {
9742                 /* force full log commit if subvolume involved. */
9743                 btrfs_set_log_full_commit(fs_info, trans);
9744         } else {
9745                 btrfs_pin_log_trans(root);
9746                 log_pinned = true;
9747                 ret = btrfs_insert_inode_ref(trans, dest,
9748                                              new_dentry->d_name.name,
9749                                              new_dentry->d_name.len,
9750                                              old_ino,
9751                                              btrfs_ino(BTRFS_I(new_dir)), index);
9752                 if (ret)
9753                         goto out_fail;
9754         }
9755
9756         inode_inc_iversion(old_dir);
9757         inode_inc_iversion(new_dir);
9758         inode_inc_iversion(old_inode);
9759         old_dir->i_ctime = old_dir->i_mtime =
9760         new_dir->i_ctime = new_dir->i_mtime =
9761         old_inode->i_ctime = current_time(old_dir);
9762
9763         if (old_dentry->d_parent != new_dentry->d_parent)
9764                 btrfs_record_unlink_dir(trans, BTRFS_I(old_dir),
9765                                 BTRFS_I(old_inode), 1);
9766
9767         if (unlikely(old_ino == BTRFS_FIRST_FREE_OBJECTID)) {
9768                 root_objectid = BTRFS_I(old_inode)->root->root_key.objectid;
9769                 ret = btrfs_unlink_subvol(trans, old_dir, root_objectid,
9770                                         old_dentry->d_name.name,
9771                                         old_dentry->d_name.len);
9772         } else {
9773                 ret = __btrfs_unlink_inode(trans, root, BTRFS_I(old_dir),
9774                                         BTRFS_I(d_inode(old_dentry)),
9775                                         old_dentry->d_name.name,
9776                                         old_dentry->d_name.len);
9777                 if (!ret)
9778                         ret = btrfs_update_inode(trans, root, old_inode);
9779         }
9780         if (ret) {
9781                 btrfs_abort_transaction(trans, ret);
9782                 goto out_fail;
9783         }
9784
9785         if (new_inode) {
9786                 inode_inc_iversion(new_inode);
9787                 new_inode->i_ctime = current_time(new_inode);
9788                 if (unlikely(btrfs_ino(BTRFS_I(new_inode)) ==
9789                              BTRFS_EMPTY_SUBVOL_DIR_OBJECTID)) {
9790                         root_objectid = BTRFS_I(new_inode)->location.objectid;
9791                         ret = btrfs_unlink_subvol(trans, new_dir, root_objectid,
9792                                                 new_dentry->d_name.name,
9793                                                 new_dentry->d_name.len);
9794                         BUG_ON(new_inode->i_nlink == 0);
9795                 } else {
9796                         ret = btrfs_unlink_inode(trans, dest, BTRFS_I(new_dir),
9797                                                  BTRFS_I(d_inode(new_dentry)),
9798                                                  new_dentry->d_name.name,
9799                                                  new_dentry->d_name.len);
9800                 }
9801                 if (!ret && new_inode->i_nlink == 0)
9802                         ret = btrfs_orphan_add(trans,
9803                                         BTRFS_I(d_inode(new_dentry)));
9804                 if (ret) {
9805                         btrfs_abort_transaction(trans, ret);
9806                         goto out_fail;
9807                 }
9808         }
9809
9810         ret = btrfs_add_link(trans, BTRFS_I(new_dir), BTRFS_I(old_inode),
9811                              new_dentry->d_name.name,
9812                              new_dentry->d_name.len, 0, index);
9813         if (ret) {
9814                 btrfs_abort_transaction(trans, ret);
9815                 goto out_fail;
9816         }
9817
9818         if (old_inode->i_nlink == 1)
9819                 BTRFS_I(old_inode)->dir_index = index;
9820
9821         if (log_pinned) {
9822                 struct dentry *parent = new_dentry->d_parent;
9823
9824                 btrfs_init_log_ctx(&ctx, old_inode);
9825                 ret = btrfs_log_new_name(trans, BTRFS_I(old_inode),
9826                                          BTRFS_I(old_dir), parent,
9827                                          false, &ctx);
9828                 if (ret == BTRFS_NEED_LOG_SYNC)
9829                         sync_log = true;
9830                 else if (ret == BTRFS_NEED_TRANS_COMMIT)
9831                         commit_transaction = true;
9832                 ret = 0;
9833                 btrfs_end_log_trans(root);
9834                 log_pinned = false;
9835         }
9836
9837         if (flags & RENAME_WHITEOUT) {
9838                 ret = btrfs_whiteout_for_rename(trans, root, old_dir,
9839                                                 old_dentry);
9840
9841                 if (ret) {
9842                         btrfs_abort_transaction(trans, ret);
9843                         goto out_fail;
9844                 }
9845         }
9846 out_fail:
9847         /*
9848          * If we have pinned the log and an error happened, we unpin tasks
9849          * trying to sync the log and force them to fallback to a transaction
9850          * commit if the log currently contains any of the inodes involved in
9851          * this rename operation (to ensure we do not persist a log with an
9852          * inconsistent state for any of these inodes or leading to any
9853          * inconsistencies when replayed). If the transaction was aborted, the
9854          * abortion reason is propagated to userspace when attempting to commit
9855          * the transaction. If the log does not contain any of these inodes, we
9856          * allow the tasks to sync it.
9857          */
9858         if (ret && log_pinned) {
9859                 if (btrfs_inode_in_log(BTRFS_I(old_dir), fs_info->generation) ||
9860                     btrfs_inode_in_log(BTRFS_I(new_dir), fs_info->generation) ||
9861                     btrfs_inode_in_log(BTRFS_I(old_inode), fs_info->generation) ||
9862                     (new_inode &&
9863                      btrfs_inode_in_log(BTRFS_I(new_inode), fs_info->generation)))
9864                         btrfs_set_log_full_commit(fs_info, trans);
9865
9866                 btrfs_end_log_trans(root);
9867                 log_pinned = false;
9868         }
9869         if (!ret && sync_log) {
9870                 ret = btrfs_sync_log(trans, BTRFS_I(old_inode)->root, &ctx);
9871                 if (ret)
9872                         commit_transaction = true;
9873         }
9874         if (commit_transaction) {
9875                 ret = btrfs_commit_transaction(trans);
9876         } else {
9877                 int ret2;
9878
9879                 ret2 = btrfs_end_transaction(trans);
9880                 ret = ret ? ret : ret2;
9881         }
9882 out_notrans:
9883         if (old_ino == BTRFS_FIRST_FREE_OBJECTID)
9884                 up_read(&fs_info->subvol_sem);
9885
9886         return ret;
9887 }
9888
9889 static int btrfs_rename2(struct inode *old_dir, struct dentry *old_dentry,
9890                          struct inode *new_dir, struct dentry *new_dentry,
9891                          unsigned int flags)
9892 {
9893         if (flags & ~(RENAME_NOREPLACE | RENAME_EXCHANGE | RENAME_WHITEOUT))
9894                 return -EINVAL;
9895
9896         if (flags & RENAME_EXCHANGE)
9897                 return btrfs_rename_exchange(old_dir, old_dentry, new_dir,
9898                                           new_dentry);
9899
9900         return btrfs_rename(old_dir, old_dentry, new_dir, new_dentry, flags);
9901 }
9902
9903 struct btrfs_delalloc_work {
9904         struct inode *inode;
9905         struct completion completion;
9906         struct list_head list;
9907         struct btrfs_work work;
9908 };
9909
9910 static void btrfs_run_delalloc_work(struct btrfs_work *work)
9911 {
9912         struct btrfs_delalloc_work *delalloc_work;
9913         struct inode *inode;
9914
9915         delalloc_work = container_of(work, struct btrfs_delalloc_work,
9916                                      work);
9917         inode = delalloc_work->inode;
9918         filemap_flush(inode->i_mapping);
9919         if (test_bit(BTRFS_INODE_HAS_ASYNC_EXTENT,
9920                                 &BTRFS_I(inode)->runtime_flags))
9921                 filemap_flush(inode->i_mapping);
9922
9923         iput(inode);
9924         complete(&delalloc_work->completion);
9925 }
9926
9927 static struct btrfs_delalloc_work *btrfs_alloc_delalloc_work(struct inode *inode)
9928 {
9929         struct btrfs_delalloc_work *work;
9930
9931         work = kmalloc(sizeof(*work), GFP_NOFS);
9932         if (!work)
9933                 return NULL;
9934
9935         init_completion(&work->completion);
9936         INIT_LIST_HEAD(&work->list);
9937         work->inode = inode;
9938         WARN_ON_ONCE(!inode);
9939         btrfs_init_work(&work->work, btrfs_flush_delalloc_helper,
9940                         btrfs_run_delalloc_work, NULL, NULL);
9941
9942         return work;
9943 }
9944
9945 /*
9946  * some fairly slow code that needs optimization. This walks the list
9947  * of all the inodes with pending delalloc and forces them to disk.
9948  */
9949 static int start_delalloc_inodes(struct btrfs_root *root, int nr)
9950 {
9951         struct btrfs_inode *binode;
9952         struct inode *inode;
9953         struct btrfs_delalloc_work *work, *next;
9954         struct list_head works;
9955         struct list_head splice;
9956         int ret = 0;
9957
9958         INIT_LIST_HEAD(&works);
9959         INIT_LIST_HEAD(&splice);
9960
9961         mutex_lock(&root->delalloc_mutex);
9962         spin_lock(&root->delalloc_lock);
9963         list_splice_init(&root->delalloc_inodes, &splice);
9964         while (!list_empty(&splice)) {
9965                 binode = list_entry(splice.next, struct btrfs_inode,
9966                                     delalloc_inodes);
9967
9968                 list_move_tail(&binode->delalloc_inodes,
9969                                &root->delalloc_inodes);
9970                 inode = igrab(&binode->vfs_inode);
9971                 if (!inode) {
9972                         cond_resched_lock(&root->delalloc_lock);
9973                         continue;
9974                 }
9975                 spin_unlock(&root->delalloc_lock);
9976
9977                 work = btrfs_alloc_delalloc_work(inode);
9978                 if (!work) {
9979                         iput(inode);
9980                         ret = -ENOMEM;
9981                         goto out;
9982                 }
9983                 list_add_tail(&work->list, &works);
9984                 btrfs_queue_work(root->fs_info->flush_workers,
9985                                  &work->work);
9986                 ret++;
9987                 if (nr != -1 && ret >= nr)
9988                         goto out;
9989                 cond_resched();
9990                 spin_lock(&root->delalloc_lock);
9991         }
9992         spin_unlock(&root->delalloc_lock);
9993
9994 out:
9995         list_for_each_entry_safe(work, next, &works, list) {
9996                 list_del_init(&work->list);
9997                 wait_for_completion(&work->completion);
9998                 kfree(work);
9999         }
10000
10001         if (!list_empty(&splice)) {
10002                 spin_lock(&root->delalloc_lock);
10003                 list_splice_tail(&splice, &root->delalloc_inodes);
10004                 spin_unlock(&root->delalloc_lock);
10005         }
10006         mutex_unlock(&root->delalloc_mutex);
10007         return ret;
10008 }
10009
10010 int btrfs_start_delalloc_inodes(struct btrfs_root *root)
10011 {
10012         struct btrfs_fs_info *fs_info = root->fs_info;
10013         int ret;
10014
10015         if (test_bit(BTRFS_FS_STATE_ERROR, &fs_info->fs_state))
10016                 return -EROFS;
10017
10018         ret = start_delalloc_inodes(root, -1);
10019         if (ret > 0)
10020                 ret = 0;
10021         return ret;
10022 }
10023
10024 int btrfs_start_delalloc_roots(struct btrfs_fs_info *fs_info, int nr)
10025 {
10026         struct btrfs_root *root;
10027         struct list_head splice;
10028         int ret;
10029
10030         if (test_bit(BTRFS_FS_STATE_ERROR, &fs_info->fs_state))
10031                 return -EROFS;
10032
10033         INIT_LIST_HEAD(&splice);
10034
10035         mutex_lock(&fs_info->delalloc_root_mutex);
10036         spin_lock(&fs_info->delalloc_root_lock);
10037         list_splice_init(&fs_info->delalloc_roots, &splice);
10038         while (!list_empty(&splice) && nr) {
10039                 root = list_first_entry(&splice, struct btrfs_root,
10040                                         delalloc_root);
10041                 root = btrfs_grab_fs_root(root);
10042                 BUG_ON(!root);
10043                 list_move_tail(&root->delalloc_root,
10044                                &fs_info->delalloc_roots);
10045                 spin_unlock(&fs_info->delalloc_root_lock);
10046
10047                 ret = start_delalloc_inodes(root, nr);
10048                 btrfs_put_fs_root(root);
10049                 if (ret < 0)
10050                         goto out;
10051
10052                 if (nr != -1) {
10053                         nr -= ret;
10054                         WARN_ON(nr < 0);
10055                 }
10056                 spin_lock(&fs_info->delalloc_root_lock);
10057         }
10058         spin_unlock(&fs_info->delalloc_root_lock);
10059
10060         ret = 0;
10061 out:
10062         if (!list_empty(&splice)) {
10063                 spin_lock(&fs_info->delalloc_root_lock);
10064                 list_splice_tail(&splice, &fs_info->delalloc_roots);
10065                 spin_unlock(&fs_info->delalloc_root_lock);
10066         }
10067         mutex_unlock(&fs_info->delalloc_root_mutex);
10068         return ret;
10069 }
10070
10071 static int btrfs_symlink(struct inode *dir, struct dentry *dentry,
10072                          const char *symname)
10073 {
10074         struct btrfs_fs_info *fs_info = btrfs_sb(dir->i_sb);
10075         struct btrfs_trans_handle *trans;
10076         struct btrfs_root *root = BTRFS_I(dir)->root;
10077         struct btrfs_path *path;
10078         struct btrfs_key key;
10079         struct inode *inode = NULL;
10080         int err;
10081         u64 objectid;
10082         u64 index = 0;
10083         int name_len;
10084         int datasize;
10085         unsigned long ptr;
10086         struct btrfs_file_extent_item *ei;
10087         struct extent_buffer *leaf;
10088
10089         name_len = strlen(symname);
10090         if (name_len > BTRFS_MAX_INLINE_DATA_SIZE(fs_info))
10091                 return -ENAMETOOLONG;
10092
10093         /*
10094          * 2 items for inode item and ref
10095          * 2 items for dir items
10096          * 1 item for updating parent inode item
10097          * 1 item for the inline extent item
10098          * 1 item for xattr if selinux is on
10099          */
10100         trans = btrfs_start_transaction(root, 7);
10101         if (IS_ERR(trans))
10102                 return PTR_ERR(trans);
10103
10104         err = btrfs_find_free_ino(root, &objectid);
10105         if (err)
10106                 goto out_unlock;
10107
10108         inode = btrfs_new_inode(trans, root, dir, dentry->d_name.name,
10109                                 dentry->d_name.len, btrfs_ino(BTRFS_I(dir)),
10110                                 objectid, S_IFLNK|S_IRWXUGO, &index);
10111         if (IS_ERR(inode)) {
10112                 err = PTR_ERR(inode);
10113                 inode = NULL;
10114                 goto out_unlock;
10115         }
10116
10117         /*
10118         * If the active LSM wants to access the inode during
10119         * d_instantiate it needs these. Smack checks to see
10120         * if the filesystem supports xattrs by looking at the
10121         * ops vector.
10122         */
10123         inode->i_fop = &btrfs_file_operations;
10124         inode->i_op = &btrfs_file_inode_operations;
10125         inode->i_mapping->a_ops = &btrfs_aops;
10126         BTRFS_I(inode)->io_tree.ops = &btrfs_extent_io_ops;
10127
10128         err = btrfs_init_inode_security(trans, inode, dir, &dentry->d_name);
10129         if (err)
10130                 goto out_unlock;
10131
10132         path = btrfs_alloc_path();
10133         if (!path) {
10134                 err = -ENOMEM;
10135                 goto out_unlock;
10136         }
10137         key.objectid = btrfs_ino(BTRFS_I(inode));
10138         key.offset = 0;
10139         key.type = BTRFS_EXTENT_DATA_KEY;
10140         datasize = btrfs_file_extent_calc_inline_size(name_len);
10141         err = btrfs_insert_empty_item(trans, root, path, &key,
10142                                       datasize);
10143         if (err) {
10144                 btrfs_free_path(path);
10145                 goto out_unlock;
10146         }
10147         leaf = path->nodes[0];
10148         ei = btrfs_item_ptr(leaf, path->slots[0],
10149                             struct btrfs_file_extent_item);
10150         btrfs_set_file_extent_generation(leaf, ei, trans->transid);
10151         btrfs_set_file_extent_type(leaf, ei,
10152                                    BTRFS_FILE_EXTENT_INLINE);
10153         btrfs_set_file_extent_encryption(leaf, ei, 0);
10154         btrfs_set_file_extent_compression(leaf, ei, 0);
10155         btrfs_set_file_extent_other_encoding(leaf, ei, 0);
10156         btrfs_set_file_extent_ram_bytes(leaf, ei, name_len);
10157
10158         ptr = btrfs_file_extent_inline_start(ei);
10159         write_extent_buffer(leaf, symname, ptr, name_len);
10160         btrfs_mark_buffer_dirty(leaf);
10161         btrfs_free_path(path);
10162
10163         inode->i_op = &btrfs_symlink_inode_operations;
10164         inode_nohighmem(inode);
10165         inode->i_mapping->a_ops = &btrfs_aops;
10166         inode_set_bytes(inode, name_len);
10167         btrfs_i_size_write(BTRFS_I(inode), name_len);
10168         err = btrfs_update_inode(trans, root, inode);
10169         /*
10170          * Last step, add directory indexes for our symlink inode. This is the
10171          * last step to avoid extra cleanup of these indexes if an error happens
10172          * elsewhere above.
10173          */
10174         if (!err)
10175                 err = btrfs_add_nondir(trans, BTRFS_I(dir), dentry,
10176                                 BTRFS_I(inode), 0, index);
10177         if (err)
10178                 goto out_unlock;
10179
10180         d_instantiate_new(dentry, inode);
10181
10182 out_unlock:
10183         btrfs_end_transaction(trans);
10184         if (err && inode) {
10185                 inode_dec_link_count(inode);
10186                 discard_new_inode(inode);
10187         }
10188         btrfs_btree_balance_dirty(fs_info);
10189         return err;
10190 }
10191
10192 static int __btrfs_prealloc_file_range(struct inode *inode, int mode,
10193                                        u64 start, u64 num_bytes, u64 min_size,
10194                                        loff_t actual_len, u64 *alloc_hint,
10195                                        struct btrfs_trans_handle *trans)
10196 {
10197         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
10198         struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
10199         struct extent_map *em;
10200         struct btrfs_root *root = BTRFS_I(inode)->root;
10201         struct btrfs_key ins;
10202         u64 cur_offset = start;
10203         u64 i_size;
10204         u64 cur_bytes;
10205         u64 last_alloc = (u64)-1;
10206         int ret = 0;
10207         bool own_trans = true;
10208         u64 end = start + num_bytes - 1;
10209
10210         if (trans)
10211                 own_trans = false;
10212         while (num_bytes > 0) {
10213                 if (own_trans) {
10214                         trans = btrfs_start_transaction(root, 3);
10215                         if (IS_ERR(trans)) {
10216                                 ret = PTR_ERR(trans);
10217                                 break;
10218                         }
10219                 }
10220
10221                 cur_bytes = min_t(u64, num_bytes, SZ_256M);
10222                 cur_bytes = max(cur_bytes, min_size);
10223                 /*
10224                  * If we are severely fragmented we could end up with really
10225                  * small allocations, so if the allocator is returning small
10226                  * chunks lets make its job easier by only searching for those
10227                  * sized chunks.
10228                  */
10229                 cur_bytes = min(cur_bytes, last_alloc);
10230                 ret = btrfs_reserve_extent(root, cur_bytes, cur_bytes,
10231                                 min_size, 0, *alloc_hint, &ins, 1, 0);
10232                 if (ret) {
10233                         if (own_trans)
10234                                 btrfs_end_transaction(trans);
10235                         break;
10236                 }
10237                 btrfs_dec_block_group_reservations(fs_info, ins.objectid);
10238
10239                 last_alloc = ins.offset;
10240                 ret = insert_reserved_file_extent(trans, inode,
10241                                                   cur_offset, ins.objectid,
10242                                                   ins.offset, ins.offset,
10243                                                   ins.offset, 0, 0, 0,
10244                                                   BTRFS_FILE_EXTENT_PREALLOC);
10245                 if (ret) {
10246                         btrfs_free_reserved_extent(fs_info, ins.objectid,
10247                                                    ins.offset, 0);
10248                         btrfs_abort_transaction(trans, ret);
10249                         if (own_trans)
10250                                 btrfs_end_transaction(trans);
10251                         break;
10252                 }
10253
10254                 btrfs_drop_extent_cache(BTRFS_I(inode), cur_offset,
10255                                         cur_offset + ins.offset -1, 0);
10256
10257                 em = alloc_extent_map();
10258                 if (!em) {
10259                         set_bit(BTRFS_INODE_NEEDS_FULL_SYNC,
10260                                 &BTRFS_I(inode)->runtime_flags);
10261                         goto next;
10262                 }
10263
10264                 em->start = cur_offset;
10265                 em->orig_start = cur_offset;
10266                 em->len = ins.offset;
10267                 em->block_start = ins.objectid;
10268                 em->block_len = ins.offset;
10269                 em->orig_block_len = ins.offset;
10270                 em->ram_bytes = ins.offset;
10271                 em->bdev = fs_info->fs_devices->latest_bdev;
10272                 set_bit(EXTENT_FLAG_PREALLOC, &em->flags);
10273                 em->generation = trans->transid;
10274
10275                 while (1) {
10276                         write_lock(&em_tree->lock);
10277                         ret = add_extent_mapping(em_tree, em, 1);
10278                         write_unlock(&em_tree->lock);
10279                         if (ret != -EEXIST)
10280                                 break;
10281                         btrfs_drop_extent_cache(BTRFS_I(inode), cur_offset,
10282                                                 cur_offset + ins.offset - 1,
10283                                                 0);
10284                 }
10285                 free_extent_map(em);
10286 next:
10287                 num_bytes -= ins.offset;
10288                 cur_offset += ins.offset;
10289                 *alloc_hint = ins.objectid + ins.offset;
10290
10291                 inode_inc_iversion(inode);
10292                 inode->i_ctime = current_time(inode);
10293                 BTRFS_I(inode)->flags |= BTRFS_INODE_PREALLOC;
10294                 if (!(mode & FALLOC_FL_KEEP_SIZE) &&
10295                     (actual_len > inode->i_size) &&
10296                     (cur_offset > inode->i_size)) {
10297                         if (cur_offset > actual_len)
10298                                 i_size = actual_len;
10299                         else
10300                                 i_size = cur_offset;
10301                         i_size_write(inode, i_size);
10302                         btrfs_ordered_update_i_size(inode, i_size, NULL);
10303                 }
10304
10305                 ret = btrfs_update_inode(trans, root, inode);
10306
10307                 if (ret) {
10308                         btrfs_abort_transaction(trans, ret);
10309                         if (own_trans)
10310                                 btrfs_end_transaction(trans);
10311                         break;
10312                 }
10313
10314                 if (own_trans)
10315                         btrfs_end_transaction(trans);
10316         }
10317         if (cur_offset < end)
10318                 btrfs_free_reserved_data_space(inode, NULL, cur_offset,
10319                         end - cur_offset + 1);
10320         return ret;
10321 }
10322
10323 int btrfs_prealloc_file_range(struct inode *inode, int mode,
10324                               u64 start, u64 num_bytes, u64 min_size,
10325                               loff_t actual_len, u64 *alloc_hint)
10326 {
10327         return __btrfs_prealloc_file_range(inode, mode, start, num_bytes,
10328                                            min_size, actual_len, alloc_hint,
10329                                            NULL);
10330 }
10331
10332 int btrfs_prealloc_file_range_trans(struct inode *inode,
10333                                     struct btrfs_trans_handle *trans, int mode,
10334                                     u64 start, u64 num_bytes, u64 min_size,
10335                                     loff_t actual_len, u64 *alloc_hint)
10336 {
10337         return __btrfs_prealloc_file_range(inode, mode, start, num_bytes,
10338                                            min_size, actual_len, alloc_hint, trans);
10339 }
10340
10341 static int btrfs_set_page_dirty(struct page *page)
10342 {
10343         return __set_page_dirty_nobuffers(page);
10344 }
10345
10346 static int btrfs_permission(struct inode *inode, int mask)
10347 {
10348         struct btrfs_root *root = BTRFS_I(inode)->root;
10349         umode_t mode = inode->i_mode;
10350
10351         if (mask & MAY_WRITE &&
10352             (S_ISREG(mode) || S_ISDIR(mode) || S_ISLNK(mode))) {
10353                 if (btrfs_root_readonly(root))
10354                         return -EROFS;
10355                 if (BTRFS_I(inode)->flags & BTRFS_INODE_READONLY)
10356                         return -EACCES;
10357         }
10358         return generic_permission(inode, mask);
10359 }
10360
10361 static int btrfs_tmpfile(struct inode *dir, struct dentry *dentry, umode_t mode)
10362 {
10363         struct btrfs_fs_info *fs_info = btrfs_sb(dir->i_sb);
10364         struct btrfs_trans_handle *trans;
10365         struct btrfs_root *root = BTRFS_I(dir)->root;
10366         struct inode *inode = NULL;
10367         u64 objectid;
10368         u64 index;
10369         int ret = 0;
10370
10371         /*
10372          * 5 units required for adding orphan entry
10373          */
10374         trans = btrfs_start_transaction(root, 5);
10375         if (IS_ERR(trans))
10376                 return PTR_ERR(trans);
10377
10378         ret = btrfs_find_free_ino(root, &objectid);
10379         if (ret)
10380                 goto out;
10381
10382         inode = btrfs_new_inode(trans, root, dir, NULL, 0,
10383                         btrfs_ino(BTRFS_I(dir)), objectid, mode, &index);
10384         if (IS_ERR(inode)) {
10385                 ret = PTR_ERR(inode);
10386                 inode = NULL;
10387                 goto out;
10388         }
10389
10390         inode->i_fop = &btrfs_file_operations;
10391         inode->i_op = &btrfs_file_inode_operations;
10392
10393         inode->i_mapping->a_ops = &btrfs_aops;
10394         BTRFS_I(inode)->io_tree.ops = &btrfs_extent_io_ops;
10395
10396         ret = btrfs_init_inode_security(trans, inode, dir, NULL);
10397         if (ret)
10398                 goto out;
10399
10400         ret = btrfs_update_inode(trans, root, inode);
10401         if (ret)
10402                 goto out;
10403         ret = btrfs_orphan_add(trans, BTRFS_I(inode));
10404         if (ret)
10405                 goto out;
10406
10407         /*
10408          * We set number of links to 0 in btrfs_new_inode(), and here we set
10409          * it to 1 because d_tmpfile() will issue a warning if the count is 0,
10410          * through:
10411          *
10412          *    d_tmpfile() -> inode_dec_link_count() -> drop_nlink()
10413          */
10414         set_nlink(inode, 1);
10415         d_tmpfile(dentry, inode);
10416         unlock_new_inode(inode);
10417         mark_inode_dirty(inode);
10418 out:
10419         btrfs_end_transaction(trans);
10420         if (ret && inode)
10421                 discard_new_inode(inode);
10422         btrfs_btree_balance_dirty(fs_info);
10423         return ret;
10424 }
10425
10426 __attribute__((const))
10427 static int btrfs_readpage_io_failed_hook(struct page *page, int failed_mirror)
10428 {
10429         return -EAGAIN;
10430 }
10431
10432 static void btrfs_check_extent_io_range(void *private_data, const char *caller,
10433                                         u64 start, u64 end)
10434 {
10435         struct inode *inode = private_data;
10436         u64 isize;
10437
10438         isize = i_size_read(inode);
10439         if (end >= PAGE_SIZE && (end % 2) == 0 && end != isize - 1) {
10440                 btrfs_debug_rl(BTRFS_I(inode)->root->fs_info,
10441                     "%s: ino %llu isize %llu odd range [%llu,%llu]",
10442                         caller, btrfs_ino(BTRFS_I(inode)), isize, start, end);
10443         }
10444 }
10445
10446 void btrfs_set_range_writeback(struct extent_io_tree *tree, u64 start, u64 end)
10447 {
10448         struct inode *inode = tree->private_data;
10449         unsigned long index = start >> PAGE_SHIFT;
10450         unsigned long end_index = end >> PAGE_SHIFT;
10451         struct page *page;
10452
10453         while (index <= end_index) {
10454                 page = find_get_page(inode->i_mapping, index);
10455                 ASSERT(page); /* Pages should be in the extent_io_tree */
10456                 set_page_writeback(page);
10457                 put_page(page);
10458                 index++;
10459         }
10460 }
10461
10462 static const struct inode_operations btrfs_dir_inode_operations = {
10463         .getattr        = btrfs_getattr,
10464         .lookup         = btrfs_lookup,
10465         .create         = btrfs_create,
10466         .unlink         = btrfs_unlink,
10467         .link           = btrfs_link,
10468         .mkdir          = btrfs_mkdir,
10469         .rmdir          = btrfs_rmdir,
10470         .rename         = btrfs_rename2,
10471         .symlink        = btrfs_symlink,
10472         .setattr        = btrfs_setattr,
10473         .mknod          = btrfs_mknod,
10474         .listxattr      = btrfs_listxattr,
10475         .permission     = btrfs_permission,
10476         .get_acl        = btrfs_get_acl,
10477         .set_acl        = btrfs_set_acl,
10478         .update_time    = btrfs_update_time,
10479         .tmpfile        = btrfs_tmpfile,
10480 };
10481 static const struct inode_operations btrfs_dir_ro_inode_operations = {
10482         .lookup         = btrfs_lookup,
10483         .permission     = btrfs_permission,
10484         .update_time    = btrfs_update_time,
10485 };
10486
10487 static const struct file_operations btrfs_dir_file_operations = {
10488         .llseek         = generic_file_llseek,
10489         .read           = generic_read_dir,
10490         .iterate_shared = btrfs_real_readdir,
10491         .open           = btrfs_opendir,
10492         .unlocked_ioctl = btrfs_ioctl,
10493 #ifdef CONFIG_COMPAT
10494         .compat_ioctl   = btrfs_compat_ioctl,
10495 #endif
10496         .release        = btrfs_release_file,
10497         .fsync          = btrfs_sync_file,
10498 };
10499
10500 static const struct extent_io_ops btrfs_extent_io_ops = {
10501         /* mandatory callbacks */
10502         .submit_bio_hook = btrfs_submit_bio_hook,
10503         .readpage_end_io_hook = btrfs_readpage_end_io_hook,
10504         .readpage_io_failed_hook = btrfs_readpage_io_failed_hook,
10505
10506         /* optional callbacks */
10507         .fill_delalloc = run_delalloc_range,
10508         .writepage_end_io_hook = btrfs_writepage_end_io_hook,
10509         .writepage_start_hook = btrfs_writepage_start_hook,
10510         .set_bit_hook = btrfs_set_bit_hook,
10511         .clear_bit_hook = btrfs_clear_bit_hook,
10512         .merge_extent_hook = btrfs_merge_extent_hook,
10513         .split_extent_hook = btrfs_split_extent_hook,
10514         .check_extent_io_range = btrfs_check_extent_io_range,
10515 };
10516
10517 /*
10518  * btrfs doesn't support the bmap operation because swapfiles
10519  * use bmap to make a mapping of extents in the file.  They assume
10520  * these extents won't change over the life of the file and they
10521  * use the bmap result to do IO directly to the drive.
10522  *
10523  * the btrfs bmap call would return logical addresses that aren't
10524  * suitable for IO and they also will change frequently as COW
10525  * operations happen.  So, swapfile + btrfs == corruption.
10526  *
10527  * For now we're avoiding this by dropping bmap.
10528  */
10529 static const struct address_space_operations btrfs_aops = {
10530         .readpage       = btrfs_readpage,
10531         .writepage      = btrfs_writepage,
10532         .writepages     = btrfs_writepages,
10533         .readpages      = btrfs_readpages,
10534         .direct_IO      = btrfs_direct_IO,
10535         .invalidatepage = btrfs_invalidatepage,
10536         .releasepage    = btrfs_releasepage,
10537         .set_page_dirty = btrfs_set_page_dirty,
10538         .error_remove_page = generic_error_remove_page,
10539 };
10540
10541 static const struct inode_operations btrfs_file_inode_operations = {
10542         .getattr        = btrfs_getattr,
10543         .setattr        = btrfs_setattr,
10544         .listxattr      = btrfs_listxattr,
10545         .permission     = btrfs_permission,
10546         .fiemap         = btrfs_fiemap,
10547         .get_acl        = btrfs_get_acl,
10548         .set_acl        = btrfs_set_acl,
10549         .update_time    = btrfs_update_time,
10550 };
10551 static const struct inode_operations btrfs_special_inode_operations = {
10552         .getattr        = btrfs_getattr,
10553         .setattr        = btrfs_setattr,
10554         .permission     = btrfs_permission,
10555         .listxattr      = btrfs_listxattr,
10556         .get_acl        = btrfs_get_acl,
10557         .set_acl        = btrfs_set_acl,
10558         .update_time    = btrfs_update_time,
10559 };
10560 static const struct inode_operations btrfs_symlink_inode_operations = {
10561         .get_link       = page_get_link,
10562         .getattr        = btrfs_getattr,
10563         .setattr        = btrfs_setattr,
10564         .permission     = btrfs_permission,
10565         .listxattr      = btrfs_listxattr,
10566         .update_time    = btrfs_update_time,
10567 };
10568
10569 const struct dentry_operations btrfs_dentry_operations = {
10570         .d_delete       = btrfs_dentry_delete,
10571 };