fs/btrfs/inode.c

   1 /*
   2  * Copyright (C) 2007 Oracle.  All rights reserved.
   3  *
   4  * This program is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU General Public
   6  * License v2 as published by the Free Software Foundation.
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  11  * General Public License for more details.
  12  *
  13  * You should have received a copy of the GNU General Public
  14  * License along with this program; if not, write to the
  15  * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  16  * Boston, MA 021110-1307, USA.
  17  */
  18
  19 #include <linux/kernel.h>
  20 #include <linux/bio.h>
  21 #include <linux/buffer_head.h>
  22 #include <linux/file.h>
  23 #include <linux/fs.h>
  24 #include <linux/pagemap.h>
  25 #include <linux/highmem.h>
  26 #include <linux/time.h>
  27 #include <linux/init.h>
  28 #include <linux/string.h>
  29 #include <linux/backing-dev.h>
  30 #include <linux/mpage.h>
  31 #include <linux/swap.h>
  32 #include <linux/writeback.h>
  33 #include <linux/statfs.h>
  34 #include <linux/compat.h>
  35 #include <linux/bit_spinlock.h>
  36 #include <linux/xattr.h>
  37 #include <linux/posix_acl.h>
  38 #include <linux/falloc.h>
  39 #include <linux/slab.h>
  40 #include <linux/ratelimit.h>
  41 #include <linux/mount.h>
  42 #include <linux/btrfs.h>
  43 #include <linux/blkdev.h>
  44 #include <linux/posix_acl_xattr.h>
  45 #include <linux/uio.h>
  46 #include "ctree.h"
  47 #include "disk-io.h"
  48 #include "transaction.h"
  49 #include "btrfs_inode.h"
  50 #include "print-tree.h"
  51 #include "ordered-data.h"
  52 #include "xattr.h"
  53 #include "tree-log.h"
  54 #include "volumes.h"
  55 #include "compression.h"
  56 #include "locking.h"
  57 #include "free-space-cache.h"
  58 #include "inode-map.h"
  59 #include "backref.h"
  60 #include "hash.h"
  61 #include "props.h"
  62 #include "qgroup.h"
  63
  64 struct btrfs_iget_args {
  65         struct btrfs_key *location;
  66         struct btrfs_root *root;
  67 };
  68
  69 struct btrfs_dio_data {
  70         u64 outstanding_extents;
  71         u64 reserve;
  72         u64 unsubmitted_oe_range_start;
  73         u64 unsubmitted_oe_range_end;
  74 };
  75
  76 static const struct inode_operations btrfs_dir_inode_operations;
  77 static const struct inode_operations btrfs_symlink_inode_operations;
  78 static const struct inode_operations btrfs_dir_ro_inode_operations;
  79 static const struct inode_operations btrfs_special_inode_operations;
  80 static const struct inode_operations btrfs_file_inode_operations;
  81 static const struct address_space_operations btrfs_aops;
  82 static const struct address_space_operations btrfs_symlink_aops;
  83 static const struct file_operations btrfs_dir_file_operations;
  84 static const struct extent_io_ops btrfs_extent_io_ops;
  85
  86 static struct kmem_cache *btrfs_inode_cachep;
  87 struct kmem_cache *btrfs_trans_handle_cachep;
  88 struct kmem_cache *btrfs_transaction_cachep;
  89 struct kmem_cache *btrfs_path_cachep;
  90 struct kmem_cache *btrfs_free_space_cachep;
  91
  92 #define S_SHIFT 12
  93 static const unsigned char btrfs_type_by_mode[S_IFMT >> S_SHIFT] = {
  94         [S_IFREG >> S_SHIFT]    = BTRFS_FT_REG_FILE,
  95         [S_IFDIR >> S_SHIFT]    = BTRFS_FT_DIR,
  96         [S_IFCHR >> S_SHIFT]    = BTRFS_FT_CHRDEV,
  97         [S_IFBLK >> S_SHIFT]    = BTRFS_FT_BLKDEV,
  98         [S_IFIFO >> S_SHIFT]    = BTRFS_FT_FIFO,
  99         [S_IFSOCK >> S_SHIFT]   = BTRFS_FT_SOCK,
 100         [S_IFLNK >> S_SHIFT]    = BTRFS_FT_SYMLINK,
 101 };
 102
 103 static int btrfs_setsize(struct inode *inode, struct iattr *attr);
 104 static int btrfs_truncate(struct inode *inode);
 105 static int btrfs_finish_ordered_io(struct btrfs_ordered_extent *ordered_extent);
 106 static noinline int cow_file_range(struct inode *inode,
 107                                    struct page *locked_page,
 108                                    u64 start, u64 end, int *page_started,
 109                                    unsigned long *nr_written, int unlock);
 110 static struct extent_map *create_pinned_em(struct inode *inode, u64 start,
 111                                            u64 len, u64 orig_start,
 112                                            u64 block_start, u64 block_len,
 113                                            u64 orig_block_len, u64 ram_bytes,
 114                                            int type);
 115
 116 static int btrfs_dirty_inode(struct inode *inode);
 117
 118 #ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
 119 void btrfs_test_inode_set_ops(struct inode *inode)
 120 {
 121         BTRFS_I(inode)->io_tree.ops = &btrfs_extent_io_ops;
 122 }
 123 #endif
 124
 125 static int btrfs_init_inode_security(struct btrfs_trans_handle *trans,
 126                                      struct inode *inode,  struct inode *dir,
 127                                      const struct qstr *qstr)
 128 {
 129         int err;
 130
 131         err = btrfs_init_acl(trans, inode, dir);
 132         if (!err)
 133                 err = btrfs_xattr_security_init(trans, inode, dir, qstr);
 134         return err;
 135 }
 136
 137 /*
 138  * this does all the hard work for inserting an inline extent into
 139  * the btree.  The caller should have done a btrfs_drop_extents so that
 140  * no overlapping inline items exist in the btree
 141  */
 142 static int insert_inline_extent(struct btrfs_trans_handle *trans,
 143                                 struct btrfs_path *path, int extent_inserted,
 144                                 struct btrfs_root *root, struct inode *inode,
 145                                 u64 start, size_t size, size_t compressed_size,
 146                                 int compress_type,
 147                                 struct page **compressed_pages)
 148 {
 149         struct extent_buffer *leaf;
 150         struct page *page = NULL;
 151         char *kaddr;
 152         unsigned long ptr;
 153         struct btrfs_file_extent_item *ei;
 154         int err = 0;
 155         int ret;
 156         size_t cur_size = size;
 157         unsigned long offset;
 158
 159         if (compressed_size && compressed_pages)
 160                 cur_size = compressed_size;
 161
 162         inode_add_bytes(inode, size);
 163
 164         if (!extent_inserted) {
 165                 struct btrfs_key key;
 166                 size_t datasize;
 167
 168                 key.objectid = btrfs_ino(inode);
 169                 key.offset = start;
 170                 key.type = BTRFS_EXTENT_DATA_KEY;
 171
 172                 datasize = btrfs_file_extent_calc_inline_size(cur_size);
 173                 path->leave_spinning = 1;
 174                 ret = btrfs_insert_empty_item(trans, root, path, &key,
 175                                               datasize);
 176                 if (ret) {
 177                         err = ret;
 178                         goto fail;
 179                 }
 180         }
 181         leaf = path->nodes[0];
 182         ei = btrfs_item_ptr(leaf, path->slots[0],
 183                             struct btrfs_file_extent_item);
 184         btrfs_set_file_extent_generation(leaf, ei, trans->transid);
 185         btrfs_set_file_extent_type(leaf, ei, BTRFS_FILE_EXTENT_INLINE);
 186         btrfs_set_file_extent_encryption(leaf, ei, 0);
 187         btrfs_set_file_extent_other_encoding(leaf, ei, 0);
 188         btrfs_set_file_extent_ram_bytes(leaf, ei, size);
 189         ptr = btrfs_file_extent_inline_start(ei);
 190
 191         if (compress_type != BTRFS_COMPRESS_NONE) {
 192                 struct page *cpage;
 193                 int i = 0;
 194                 while (compressed_size > 0) {
 195                         cpage = compressed_pages[i];
 196                         cur_size = min_t(unsigned long, compressed_size,
 197                                        PAGE_SIZE);
 198
 199                         kaddr = kmap_atomic(cpage);
 200                         write_extent_buffer(leaf, kaddr, ptr, cur_size);
 201                         kunmap_atomic(kaddr);
 202
 203                         i++;
 204                         ptr += cur_size;
 205                         compressed_size -= cur_size;
 206                 }
 207                 btrfs_set_file_extent_compression(leaf, ei,
 208                                                   compress_type);
 209         } else {
 210                 page = find_get_page(inode->i_mapping,
 211                                      start >> PAGE_SHIFT);
 212                 btrfs_set_file_extent_compression(leaf, ei, 0);
 213                 kaddr = kmap_atomic(page);
 214                 offset = start & (PAGE_SIZE - 1);
 215                 write_extent_buffer(leaf, kaddr + offset, ptr, size);
 216                 kunmap_atomic(kaddr);
 217                 put_page(page);
 218         }
 219         btrfs_mark_buffer_dirty(leaf);
 220         btrfs_release_path(path);
 221
 222         /*
 223          * we're an inline extent, so nobody can
 224          * extend the file past i_size without locking
 225          * a page we already have locked.
 226          *
 227          * We must do any isize and inode updates
 228          * before we unlock the pages.  Otherwise we
 229          * could end up racing with unlink.
 230          */
 231         BTRFS_I(inode)->disk_i_size = inode->i_size;
 232         ret = btrfs_update_inode(trans, root, inode);
 233
 234         return ret;
 235 fail:
 236         return err;
 237 }
 238
 239
 240 /*
 241  * conditionally insert an inline extent into the file.  This
 242  * does the checks required to make sure the data is small enough
 243  * to fit as an inline extent.
 244  */
 245 static noinline int cow_file_range_inline(struct btrfs_root *root,
 246                                           struct inode *inode, u64 start,
 247                                           u64 end, size_t compressed_size,
 248                                           int compress_type,
 249                                           struct page **compressed_pages)
 250 {
 251         struct btrfs_trans_handle *trans;
 252         u64 isize = i_size_read(inode);
 253         u64 actual_end = min(end + 1, isize);
 254         u64 inline_len = actual_end - start;
 255         u64 aligned_end = ALIGN(end, root->sectorsize);
 256         u64 data_len = inline_len;
 257         int ret;
 258         struct btrfs_path *path;
 259         int extent_inserted = 0;
 260         u32 extent_item_size;
 261
 262         if (compressed_size)
 263                 data_len = compressed_size;
 264
 265         if (start > 0 ||
 266             actual_end > root->sectorsize ||
 267             data_len > BTRFS_MAX_INLINE_DATA_SIZE(root) ||
 268             (!compressed_size &&
 269             (actual_end & (root->sectorsize - 1)) == 0) ||
 270             end + 1 < isize ||
 271             data_len > root->fs_info->max_inline) {
 272                 return 1;
 273         }
 274
 275         path = btrfs_alloc_path();
 276         if (!path)
 277                 return -ENOMEM;
 278
 279         trans = btrfs_join_transaction(root);
 280         if (IS_ERR(trans)) {
 281                 btrfs_free_path(path);
 282                 return PTR_ERR(trans);
 283         }
 284         trans->block_rsv = &root->fs_info->delalloc_block_rsv;
 285
 286         if (compressed_size && compressed_pages)
 287                 extent_item_size = btrfs_file_extent_calc_inline_size(
 288                    compressed_size);
 289         else
 290                 extent_item_size = btrfs_file_extent_calc_inline_size(
 291                     inline_len);
 292
 293         ret = __btrfs_drop_extents(trans, root, inode, path,
 294                                    start, aligned_end, NULL,
 295                                    1, 1, extent_item_size, &extent_inserted);
 296         if (ret) {
 297                 btrfs_abort_transaction(trans, root, ret);
 298                 goto out;
 299         }
 300
 301         if (isize > actual_end)
 302                 inline_len = min_t(u64, isize, actual_end);
 303         ret = insert_inline_extent(trans, path, extent_inserted,
 304                                    root, inode, start,
 305                                    inline_len, compressed_size,
 306                                    compress_type, compressed_pages);
 307         if (ret && ret != -ENOSPC) {
 308                 btrfs_abort_transaction(trans, root, ret);
 309                 goto out;
 310         } else if (ret == -ENOSPC) {
 311                 ret = 1;
 312                 goto out;
 313         }
 314
 315         set_bit(BTRFS_INODE_NEEDS_FULL_SYNC, &BTRFS_I(inode)->runtime_flags);
 316         btrfs_delalloc_release_metadata(inode, end + 1 - start);
 317         btrfs_drop_extent_cache(inode, start, aligned_end - 1, 0);
 318 out:
 319         /*
 320          * Don't forget to free the reserved space, as for inlined extent
 321          * it won't count as data extent, free them directly here.
 322          * And at reserve time, it's always aligned to page size, so
 323          * just free one page here.
 324          */
 325         btrfs_qgroup_free_data(inode, 0, PAGE_SIZE);
 326         btrfs_free_path(path);
 327         btrfs_end_transaction(trans, root);
 328         return ret;
 329 }
 330
 331 struct async_extent {
 332         u64 start;
 333         u64 ram_size;
 334         u64 compressed_size;
 335         struct page **pages;
 336         unsigned long nr_pages;
 337         int compress_type;
 338         struct list_head list;
 339 };
 340
 341 struct async_cow {
 342         struct inode *inode;
 343         struct btrfs_root *root;
 344         struct page *locked_page;
 345         u64 start;
 346         u64 end;
 347         struct list_head extents;
 348         struct btrfs_work work;
 349 };
 350
 351 static noinline int add_async_extent(struct async_cow *cow,
 352                                      u64 start, u64 ram_size,
 353                                      u64 compressed_size,
 354                                      struct page **pages,
 355                                      unsigned long nr_pages,
 356                                      int compress_type)
 357 {
 358         struct async_extent *async_extent;
 359
 360         async_extent = kmalloc(sizeof(*async_extent), GFP_NOFS);
 361         BUG_ON(!async_extent); /* -ENOMEM */
 362         async_extent->start = start;
 363         async_extent->ram_size = ram_size;
 364         async_extent->compressed_size = compressed_size;
 365         async_extent->pages = pages;
 366         async_extent->nr_pages = nr_pages;
 367         async_extent->compress_type = compress_type;
 368         list_add_tail(&async_extent->list, &cow->extents);
 369         return 0;
 370 }
 371
 372 static inline int inode_need_compress(struct inode *inode)
 373 {
 374         struct btrfs_root *root = BTRFS_I(inode)->root;
 375
 376         /* force compress */
 377         if (btrfs_test_opt(root, FORCE_COMPRESS))
 378                 return 1;
 379         /* bad compression ratios */
 380         if (BTRFS_I(inode)->flags & BTRFS_INODE_NOCOMPRESS)
 381                 return 0;
 382         if (btrfs_test_opt(root, COMPRESS) ||
 383             BTRFS_I(inode)->flags & BTRFS_INODE_COMPRESS ||
 384             BTRFS_I(inode)->force_compress)
 385                 return 1;
 386         return 0;
 387 }
 388
 389 /*
 390  * we create compressed extents in two phases.  The first
 391  * phase compresses a range of pages that have already been
 392  * locked (both pages and state bits are locked).
 393  *
 394  * This is done inside an ordered work queue, and the compression
 395  * is spread across many cpus.  The actual IO submission is step
 396  * two, and the ordered work queue takes care of making sure that
 397  * happens in the same order things were put onto the queue by
 398  * writepages and friends.
 399  *
 400  * If this code finds it can't get good compression, it puts an
 401  * entry onto the work queue to write the uncompressed bytes.  This
 402  * makes sure that both compressed inodes and uncompressed inodes
 403  * are written in the same order that the flusher thread sent them
 404  * down.
 405  */
 406 static noinline void compress_file_range(struct inode *inode,
 407                                         struct page *locked_page,
 408                                         u64 start, u64 end,
 409                                         struct async_cow *async_cow,
 410                                         int *num_added)
 411 {
 412         struct btrfs_root *root = BTRFS_I(inode)->root;
 413         u64 num_bytes;
 414         u64 blocksize = root->sectorsize;
 415         u64 actual_end;
 416         u64 isize = i_size_read(inode);
 417         int ret = 0;
 418         struct page **pages = NULL;
 419         unsigned long nr_pages;
 420         unsigned long nr_pages_ret = 0;
 421         unsigned long total_compressed = 0;
 422         unsigned long total_in = 0;
 423         unsigned long max_compressed = SZ_128K;
 424         unsigned long max_uncompressed = SZ_128K;
 425         int i;
 426         int will_compress;
 427         int compress_type = root->fs_info->compress_type;
 428         int redirty = 0;
 429
 430         /* if this is a small write inside eof, kick off a defrag */
 431         if ((end - start + 1) < SZ_16K &&
 432             (start > 0 || end + 1 < BTRFS_I(inode)->disk_i_size))
 433                 btrfs_add_inode_defrag(NULL, inode);
 434
 435         actual_end = min_t(u64, isize, end + 1);
 436 again:
 437         will_compress = 0;
 438         nr_pages = (end >> PAGE_SHIFT) - (start >> PAGE_SHIFT) + 1;
 439         nr_pages = min_t(unsigned long, nr_pages, SZ_128K / PAGE_SIZE);
 440
 441         /*
 442          * we don't want to send crud past the end of i_size through
 443          * compression, that's just a waste of CPU time.  So, if the
 444          * end of the file is before the start of our current
 445          * requested range of bytes, we bail out to the uncompressed
 446          * cleanup code that can deal with all of this.
 447          *
 448          * It isn't really the fastest way to fix things, but this is a
 449          * very uncommon corner.
 450          */
 451         if (actual_end <= start)
 452                 goto cleanup_and_bail_uncompressed;
 453
 454         total_compressed = actual_end - start;
 455
 456         /*
 457          * skip compression for a small file range(<=blocksize) that
 458          * isn't an inline extent, since it dosen't save disk space at all.
 459          */
 460         if (total_compressed <= blocksize &&
 461            (start > 0 || end + 1 < BTRFS_I(inode)->disk_i_size))
 462                 goto cleanup_and_bail_uncompressed;
 463
 464         /* we want to make sure that amount of ram required to uncompress
 465          * an extent is reasonable, so we limit the total size in ram
 466          * of a compressed extent to 128k.  This is a crucial number
 467          * because it also controls how easily we can spread reads across
 468          * cpus for decompression.
 469          *
 470          * We also want to make sure the amount of IO required to do
 471          * a random read is reasonably small, so we limit the size of
 472          * a compressed extent to 128k.
 473          */
 474         total_compressed = min(total_compressed, max_uncompressed);
 475         num_bytes = ALIGN(end - start + 1, blocksize);
 476         num_bytes = max(blocksize,  num_bytes);
 477         total_in = 0;
 478         ret = 0;
 479
 480         /*
 481          * we do compression for mount -o compress and when the
 482          * inode has not been flagged as nocompress.  This flag can
 483          * change at any time if we discover bad compression ratios.
 484          */
 485         if (inode_need_compress(inode)) {
 486                 WARN_ON(pages);
 487                 pages = kcalloc(nr_pages, sizeof(struct page *), GFP_NOFS);
 488                 if (!pages) {
 489                         /* just bail out to the uncompressed code */
 490                         goto cont;
 491                 }
 492
 493                 if (BTRFS_I(inode)->force_compress)
 494                         compress_type = BTRFS_I(inode)->force_compress;
 495
 496                 /*
 497                  * we need to call clear_page_dirty_for_io on each
 498                  * page in the range.  Otherwise applications with the file
 499                  * mmap'd can wander in and change the page contents while
 500                  * we are compressing them.
 501                  *
 502                  * If the compression fails for any reason, we set the pages
 503                  * dirty again later on.
 504                  */
 505                 extent_range_clear_dirty_for_io(inode, start, end);
 506                 redirty = 1;
 507                 ret = btrfs_compress_pages(compress_type,
 508                                            inode->i_mapping, start,
 509                                            total_compressed, pages,
 510                                            nr_pages, &nr_pages_ret,
 511                                            &total_in,
 512                                            &total_compressed,
 513                                            max_compressed);
 514
 515                 if (!ret) {
 516                         unsigned long offset = total_compressed &
 517                                 (PAGE_SIZE - 1);
 518                         struct page *page = pages[nr_pages_ret - 1];
 519                         char *kaddr;
 520
 521                         /* zero the tail end of the last page, we might be
 522                          * sending it down to disk
 523                          */
 524                         if (offset) {
 525                                 kaddr = kmap_atomic(page);
 526                                 memset(kaddr + offset, 0,
 527                                        PAGE_SIZE - offset);
 528                                 kunmap_atomic(kaddr);
 529                         }
 530                         will_compress = 1;
 531                 }
 532         }
 533 cont:
 534         if (start == 0) {
 535                 /* lets try to make an inline extent */
 536                 if (ret || total_in < (actual_end - start)) {
 537                         /* we didn't compress the entire range, try
 538                          * to make an uncompressed inline extent.
 539                          */
 540                         ret = cow_file_range_inline(root, inode, start, end,
 541                                                     0, 0, NULL);
 542                 } else {
 543                         /* try making a compressed inline extent */
 544                         ret = cow_file_range_inline(root, inode, start, end,
 545                                                     total_compressed,
 546                                                     compress_type, pages);
 547                 }
 548                 if (ret <= 0) {
 549                         unsigned long clear_flags = EXTENT_DELALLOC |
 550                                 EXTENT_DEFRAG;
 551                         unsigned long page_error_op;
 552
 553                         clear_flags |= (ret < 0) ? EXTENT_DO_ACCOUNTING : 0;
 554                         page_error_op = ret < 0 ? PAGE_SET_ERROR : 0;
 555
 556                         /*
 557                          * inline extent creation worked or returned error,
 558                          * we don't need to create any more async work items.
 559                          * Unlock and free up our temp pages.
 560                          */
 561                         extent_clear_unlock_delalloc(inode, start, end, NULL,
 562                                                      clear_flags, PAGE_UNLOCK |
 563                                                      PAGE_CLEAR_DIRTY |
 564                                                      PAGE_SET_WRITEBACK |
 565                                                      page_error_op |
 566                                                      PAGE_END_WRITEBACK);
 567                         goto free_pages_out;
 568                 }
 569         }
 570
 571         if (will_compress) {
 572                 /*
 573                  * we aren't doing an inline extent round the compressed size
 574                  * up to a block size boundary so the allocator does sane
 575                  * things
 576                  */
 577                 total_compressed = ALIGN(total_compressed, blocksize);
 578
 579                 /*
 580                  * one last check to make sure the compression is really a
 581                  * win, compare the page count read with the blocks on disk
 582                  */
 583                 total_in = ALIGN(total_in, PAGE_SIZE);
 584                 if (total_compressed >= total_in) {
 585                         will_compress = 0;
 586                 } else {
 587                         num_bytes = total_in;
 588                 }
 589         }
 590         if (!will_compress && pages) {
 591                 /*
 592                  * the compression code ran but failed to make things smaller,
 593                  * free any pages it allocated and our page pointer array
 594                  */
 595                 for (i = 0; i < nr_pages_ret; i++) {
 596                         WARN_ON(pages[i]->mapping);
 597                         put_page(pages[i]);
 598                 }
 599                 kfree(pages);
 600                 pages = NULL;
 601                 total_compressed = 0;
 602                 nr_pages_ret = 0;
 603
 604                 /* flag the file so we don't compress in the future */
 605                 if (!btrfs_test_opt(root, FORCE_COMPRESS) &&
 606                     !(BTRFS_I(inode)->force_compress)) {
 607                         BTRFS_I(inode)->flags |= BTRFS_INODE_NOCOMPRESS;
 608                 }
 609         }
 610         if (will_compress) {
 611                 *num_added += 1;
 612
 613                 /* the async work queues will take care of doing actual
 614                  * allocation on disk for these compressed pages,
 615                  * and will submit them to the elevator.
 616                  */
 617                 add_async_extent(async_cow, start, num_bytes,
 618                                  total_compressed, pages, nr_pages_ret,
 619                                  compress_type);
 620
 621                 if (start + num_bytes < end) {
 622                         start += num_bytes;
 623                         pages = NULL;
 624                         cond_resched();
 625                         goto again;
 626                 }
 627         } else {
 628 cleanup_and_bail_uncompressed:
 629                 /*
 630                  * No compression, but we still need to write the pages in
 631                  * the file we've been given so far.  redirty the locked
 632                  * page if it corresponds to our extent and set things up
 633                  * for the async work queue to run cow_file_range to do
 634                  * the normal delalloc dance
 635                  */
 636                 if (page_offset(locked_page) >= start &&
 637                     page_offset(locked_page) <= end) {
 638                         __set_page_dirty_nobuffers(locked_page);
 639                         /* unlocked later on in the async handlers */
 640                 }
 641                 if (redirty)
 642                         extent_range_redirty_for_io(inode, start, end);
 643                 add_async_extent(async_cow, start, end - start + 1,
 644                                  0, NULL, 0, BTRFS_COMPRESS_NONE);
 645                 *num_added += 1;
 646         }
 647
 648         return;
 649
 650 free_pages_out:
 651         for (i = 0; i < nr_pages_ret; i++) {
 652                 WARN_ON(pages[i]->mapping);
 653                 put_page(pages[i]);
 654         }
 655         kfree(pages);
 656 }
 657
 658 static void free_async_extent_pages(struct async_extent *async_extent)
 659 {
 660         int i;
 661
 662         if (!async_extent->pages)
 663                 return;
 664
 665         for (i = 0; i < async_extent->nr_pages; i++) {
 666                 WARN_ON(async_extent->pages[i]->mapping);
 667                 put_page(async_extent->pages[i]);
 668         }
 669         kfree(async_extent->pages);
 670         async_extent->nr_pages = 0;
 671         async_extent->pages = NULL;
 672 }
 673
 674 /*
 675  * phase two of compressed writeback.  This is the ordered portion
 676  * of the code, which only gets called in the order the work was
 677  * queued.  We walk all the async extents created by compress_file_range
 678  * and send them down to the disk.
 679  */
 680 static noinline void submit_compressed_extents(struct inode *inode,
 681                                               struct async_cow *async_cow)
 682 {
 683         struct async_extent *async_extent;
 684         u64 alloc_hint = 0;
 685         struct btrfs_key ins;
 686         struct extent_map *em;
 687         struct btrfs_root *root = BTRFS_I(inode)->root;
 688         struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
 689         struct extent_io_tree *io_tree;
 690         int ret = 0;
 691
 692 again:
 693         while (!list_empty(&async_cow->extents)) {
 694                 async_extent = list_entry(async_cow->extents.next,
 695                                           struct async_extent, list);
 696                 list_del(&async_extent->list);
 697
 698                 io_tree = &BTRFS_I(inode)->io_tree;
 699
 700 retry:
 701                 /* did the compression code fall back to uncompressed IO? */
 702                 if (!async_extent->pages) {
 703                         int page_started = 0;
 704                         unsigned long nr_written = 0;
 705
 706                         lock_extent(io_tree, async_extent->start,
 707                                          async_extent->start +
 708                                          async_extent->ram_size - 1);
 709
 710                         /* allocate blocks */
 711                         ret = cow_file_range(inode, async_cow->locked_page,
 712                                              async_extent->start,
 713                                              async_extent->start +
 714                                              async_extent->ram_size - 1,
 715                                              &page_started, &nr_written, 0);
 716
 717                         /* JDM XXX */
 718
 719                         /*
 720                          * if page_started, cow_file_range inserted an
 721                          * inline extent and took care of all the unlocking
 722                          * and IO for us.  Otherwise, we need to submit
 723                          * all those pages down to the drive.
 724                          */
 725                         if (!page_started && !ret)
 726                                 extent_write_locked_range(io_tree,
 727                                                   inode, async_extent->start,
 728                                                   async_extent->start +
 729                                                   async_extent->ram_size - 1,
 730                                                   btrfs_get_extent,
 731                                                   WB_SYNC_ALL);
 732                         else if (ret)
 733                                 unlock_page(async_cow->locked_page);
 734                         kfree(async_extent);
 735                         cond_resched();
 736                         continue;
 737                 }
 738
 739                 lock_extent(io_tree, async_extent->start,
 740                             async_extent->start + async_extent->ram_size - 1);
 741
 742                 ret = btrfs_reserve_extent(root,
 743                                            async_extent->compressed_size,
 744                                            async_extent->compressed_size,
 745                                            0, alloc_hint, &ins, 1, 1);
 746                 if (ret) {
 747                         free_async_extent_pages(async_extent);
 748
 749                         if (ret == -ENOSPC) {
 750                                 unlock_extent(io_tree, async_extent->start,
 751                                               async_extent->start +
 752                                               async_extent->ram_size - 1);
 753
 754                                 /*
 755                                  * we need to redirty the pages if we decide to
 756                                  * fallback to uncompressed IO, otherwise we
 757                                  * will not submit these pages down to lower
 758                                  * layers.
 759                                  */
 760                                 extent_range_redirty_for_io(inode,
 761                                                 async_extent->start,
 762                                                 async_extent->start +
 763                                                 async_extent->ram_size - 1);
 764
 765                                 goto retry;
 766                         }
 767                         goto out_free;
 768                 }
 769                 /*
 770                  * here we're doing allocation and writeback of the
 771                  * compressed pages
 772                  */
 773                 btrfs_drop_extent_cache(inode, async_extent->start,
 774                                         async_extent->start +
 775                                         async_extent->ram_size - 1, 0);
 776
 777                 em = alloc_extent_map();
 778                 if (!em) {
 779                         ret = -ENOMEM;
 780                         goto out_free_reserve;
 781                 }
 782                 em->start = async_extent->start;
 783                 em->len = async_extent->ram_size;
 784                 em->orig_start = em->start;
 785                 em->mod_start = em->start;
 786                 em->mod_len = em->len;
 787
 788                 em->block_start = ins.objectid;
 789                 em->block_len = ins.offset;
 790                 em->orig_block_len = ins.offset;
 791                 em->ram_bytes = async_extent->ram_size;
 792                 em->bdev = root->fs_info->fs_devices->latest_bdev;
 793                 em->compress_type = async_extent->compress_type;
 794                 set_bit(EXTENT_FLAG_PINNED, &em->flags);
 795                 set_bit(EXTENT_FLAG_COMPRESSED, &em->flags);
 796                 em->generation = -1;
 797
 798                 while (1) {
 799                         write_lock(&em_tree->lock);
 800                         ret = add_extent_mapping(em_tree, em, 1);
 801                         write_unlock(&em_tree->lock);
 802                         if (ret != -EEXIST) {
 803                                 free_extent_map(em);
 804                                 break;
 805                         }
 806                         btrfs_drop_extent_cache(inode, async_extent->start,
 807                                                 async_extent->start +
 808                                                 async_extent->ram_size - 1, 0);
 809                 }
 810
 811                 if (ret)
 812                         goto out_free_reserve;
 813
 814                 ret = btrfs_add_ordered_extent_compress(inode,
 815                                                 async_extent->start,
 816                                                 ins.objectid,
 817                                                 async_extent->ram_size,
 818                                                 ins.offset,
 819                                                 BTRFS_ORDERED_COMPRESSED,
 820                                                 async_extent->compress_type);
 821                 if (ret) {
 822                         btrfs_drop_extent_cache(inode, async_extent->start,
 823                                                 async_extent->start +
 824                                                 async_extent->ram_size - 1, 0);
 825                         goto out_free_reserve;
 826                 }
 827
 828                 /*
 829                  * clear dirty, set writeback and unlock the pages.
 830                  */
 831                 extent_clear_unlock_delalloc(inode, async_extent->start,
 832                                 async_extent->start +
 833                                 async_extent->ram_size - 1,
 834                                 NULL, EXTENT_LOCKED | EXTENT_DELALLOC,
 835                                 PAGE_UNLOCK | PAGE_CLEAR_DIRTY |
 836                                 PAGE_SET_WRITEBACK);
 837                 ret = btrfs_submit_compressed_write(inode,
 838                                     async_extent->start,
 839                                     async_extent->ram_size,
 840                                     ins.objectid,
 841                                     ins.offset, async_extent->pages,
 842                                     async_extent->nr_pages);
 843                 if (ret) {
 844                         struct extent_io_tree *tree = &BTRFS_I(inode)->io_tree;
 845                         struct page *p = async_extent->pages[0];
 846                         const u64 start = async_extent->start;
 847                         const u64 end = start + async_extent->ram_size - 1;
 848
 849                         p->mapping = inode->i_mapping;
 850                         tree->ops->writepage_end_io_hook(p, start, end,
 851                                                          NULL, 0);
 852                         p->mapping = NULL;
 853                         extent_clear_unlock_delalloc(inode, start, end, NULL, 0,
 854                                                      PAGE_END_WRITEBACK |
 855                                                      PAGE_SET_ERROR);
 856                         free_async_extent_pages(async_extent);
 857                 }
 858                 alloc_hint = ins.objectid + ins.offset;
 859                 kfree(async_extent);
 860                 cond_resched();
 861         }
 862         return;
 863 out_free_reserve:
 864         btrfs_free_reserved_extent(root, ins.objectid, ins.offset, 1);
 865 out_free:
 866         extent_clear_unlock_delalloc(inode, async_extent->start,
 867                                      async_extent->start +
 868                                      async_extent->ram_size - 1,
 869                                      NULL, EXTENT_LOCKED | EXTENT_DELALLOC |
 870                                      EXTENT_DEFRAG | EXTENT_DO_ACCOUNTING,
 871                                      PAGE_UNLOCK | PAGE_CLEAR_DIRTY |
 872                                      PAGE_SET_WRITEBACK | PAGE_END_WRITEBACK |
 873                                      PAGE_SET_ERROR);
 874         free_async_extent_pages(async_extent);
 875         kfree(async_extent);
 876         goto again;
 877 }
 878
 879 static u64 get_extent_allocation_hint(struct inode *inode, u64 start,
 880                                       u64 num_bytes)
 881 {
 882         struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
 883         struct extent_map *em;
 884         u64 alloc_hint = 0;
 885
 886         read_lock(&em_tree->lock);
 887         em = search_extent_mapping(em_tree, start, num_bytes);
 888         if (em) {
 889                 /*
 890                  * if block start isn't an actual block number then find the
 891                  * first block in this inode and use that as a hint.  If that
 892                  * block is also bogus then just don't worry about it.
 893                  */
 894                 if (em->block_start >= EXTENT_MAP_LAST_BYTE) {
 895                         free_extent_map(em);
 896                         em = search_extent_mapping(em_tree, 0, 0);
 897                         if (em && em->block_start < EXTENT_MAP_LAST_BYTE)
 898                                 alloc_hint = em->block_start;
 899                         if (em)
 900                                 free_extent_map(em);
 901                 } else {
 902                         alloc_hint = em->block_start;
 903                         free_extent_map(em);
 904                 }
 905         }
 906         read_unlock(&em_tree->lock);
 907
 908         return alloc_hint;
 909 }
 910
 911 /*
 912  * when extent_io.c finds a delayed allocation range in the file,
 913  * the call backs end up in this code.  The basic idea is to
 914  * allocate extents on disk for the range, and create ordered data structs
 915  * in ram to track those extents.
 916  *
 917  * locked_page is the page that writepage had locked already.  We use
 918  * it to make sure we don't do extra locks or unlocks.
 919  *
 920  * *page_started is set to one if we unlock locked_page and do everything
 921  * required to start IO on it.  It may be clean and already done with
 922  * IO when we return.
 923  */
 924 static noinline int cow_file_range(struct inode *inode,
 925                                    struct page *locked_page,
 926                                    u64 start, u64 end, int *page_started,
 927                                    unsigned long *nr_written,
 928                                    int unlock)
 929 {
 930         struct btrfs_root *root = BTRFS_I(inode)->root;
 931         u64 alloc_hint = 0;
 932         u64 num_bytes;
 933         unsigned long ram_size;
 934         u64 disk_num_bytes;
 935         u64 cur_alloc_size;
 936         u64 blocksize = root->sectorsize;
 937         struct btrfs_key ins;
 938         struct extent_map *em;
 939         struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
 940         int ret = 0;
 941
 942         if (btrfs_is_free_space_inode(inode)) {
 943                 WARN_ON_ONCE(1);
 944                 ret = -EINVAL;
 945                 goto out_unlock;
 946         }
 947
 948         num_bytes = ALIGN(end - start + 1, blocksize);
 949         num_bytes = max(blocksize,  num_bytes);
 950         disk_num_bytes = num_bytes;
 951
 952         /* if this is a small write inside eof, kick off defrag */
 953         if (num_bytes < SZ_64K &&
 954             (start > 0 || end + 1 < BTRFS_I(inode)->disk_i_size))
 955                 btrfs_add_inode_defrag(NULL, inode);
 956
 957         if (start == 0) {
 958                 /* lets try to make an inline extent */
 959                 ret = cow_file_range_inline(root, inode, start, end, 0, 0,
 960                                             NULL);
 961                 if (ret == 0) {
 962                         extent_clear_unlock_delalloc(inode, start, end, NULL,
 963                                      EXTENT_LOCKED | EXTENT_DELALLOC |
 964                                      EXTENT_DEFRAG, PAGE_UNLOCK |
 965                                      PAGE_CLEAR_DIRTY | PAGE_SET_WRITEBACK |
 966                                      PAGE_END_WRITEBACK);
 967
 968                         *nr_written = *nr_written +
 969                              (end - start + PAGE_SIZE) / PAGE_SIZE;
 970                         *page_started = 1;
 971                         goto out;
 972                 } else if (ret < 0) {
 973                         goto out_unlock;
 974                 }
 975         }
 976
 977         BUG_ON(disk_num_bytes >
 978                btrfs_super_total_bytes(root->fs_info->super_copy));
 979
 980         alloc_hint = get_extent_allocation_hint(inode, start, num_bytes);
 981         btrfs_drop_extent_cache(inode, start, start + num_bytes - 1, 0);
 982
 983         while (disk_num_bytes > 0) {
 984                 unsigned long op;
 985
 986                 cur_alloc_size = disk_num_bytes;
 987                 ret = btrfs_reserve_extent(root, cur_alloc_size,
 988                                            root->sectorsize, 0, alloc_hint,
 989                                            &ins, 1, 1);
 990                 if (ret < 0)
 991                         goto out_unlock;
 992
 993                 em = alloc_extent_map();
 994                 if (!em) {
 995                         ret = -ENOMEM;
 996                         goto out_reserve;
 997                 }
 998                 em->start = start;
 999                 em->orig_start = em->start;
1000                 ram_size = ins.offset;
1001                 em->len = ins.offset;
1002                 em->mod_start = em->start;
1003                 em->mod_len = em->len;
1004
1005                 em->block_start = ins.objectid;
1006                 em->block_len = ins.offset;
1007                 em->orig_block_len = ins.offset;
1008                 em->ram_bytes = ram_size;
1009                 em->bdev = root->fs_info->fs_devices->latest_bdev;
1010                 set_bit(EXTENT_FLAG_PINNED, &em->flags);
1011                 em->generation = -1;
1012
1013                 while (1) {
1014                         write_lock(&em_tree->lock);
1015                         ret = add_extent_mapping(em_tree, em, 1);
1016                         write_unlock(&em_tree->lock);
1017                         if (ret != -EEXIST) {
1018                                 free_extent_map(em);
1019                                 break;
1020                         }
1021                         btrfs_drop_extent_cache(inode, start,
1022                                                 start + ram_size - 1, 0);
1023                 }
1024                 if (ret)
1025                         goto out_reserve;
1026
1027                 cur_alloc_size = ins.offset;
1028                 ret = btrfs_add_ordered_extent(inode, start, ins.objectid,
1029                                                ram_size, cur_alloc_size, 0);
1030                 if (ret)
1031                         goto out_drop_extent_cache;
1032
1033                 if (root->root_key.objectid ==
1034                     BTRFS_DATA_RELOC_TREE_OBJECTID) {
1035                         ret = btrfs_reloc_clone_csums(inode, start,
1036                                                       cur_alloc_size);
1037                         if (ret)
1038                                 goto out_drop_extent_cache;
1039                 }
1040
1041                 if (disk_num_bytes < cur_alloc_size)
1042                         break;
1043
1044                 /* we're not doing compressed IO, don't unlock the first
1045                  * page (which the caller expects to stay locked), don't
1046                  * clear any dirty bits and don't set any writeback bits
1047                  *
1048                  * Do set the Private2 bit so we know this page was properly
1049                  * setup for writepage
1050                  */
1051                 op = unlock ? PAGE_UNLOCK : 0;
1052                 op |= PAGE_SET_PRIVATE2;
1053
1054                 extent_clear_unlock_delalloc(inode, start,
1055                                              start + ram_size - 1, locked_page,
1056                                              EXTENT_LOCKED | EXTENT_DELALLOC,
1057                                              op);
1058                 disk_num_bytes -= cur_alloc_size;
1059                 num_bytes -= cur_alloc_size;
1060                 alloc_hint = ins.objectid + ins.offset;
1061                 start += cur_alloc_size;
1062         }
1063 out:
1064         return ret;
1065
1066 out_drop_extent_cache:
1067         btrfs_drop_extent_cache(inode, start, start + ram_size - 1, 0);
1068 out_reserve:
1069         btrfs_free_reserved_extent(root, ins.objectid, ins.offset, 1);
1070 out_unlock:
1071         extent_clear_unlock_delalloc(inode, start, end, locked_page,
1072                                      EXTENT_LOCKED | EXTENT_DO_ACCOUNTING |
1073                                      EXTENT_DELALLOC | EXTENT_DEFRAG,
1074                                      PAGE_UNLOCK | PAGE_CLEAR_DIRTY |
1075                                      PAGE_SET_WRITEBACK | PAGE_END_WRITEBACK);
1076         goto out;
1077 }
1078
1079 /*
1080  * work queue call back to started compression on a file and pages
1081  */
1082 static noinline void async_cow_start(struct btrfs_work *work)
1083 {
1084         struct async_cow *async_cow;
1085         int num_added = 0;
1086         async_cow = container_of(work, struct async_cow, work);
1087
1088         compress_file_range(async_cow->inode, async_cow->locked_page,
1089                             async_cow->start, async_cow->end, async_cow,
1090                             &num_added);
1091         if (num_added == 0) {
1092                 btrfs_add_delayed_iput(async_cow->inode);
1093                 async_cow->inode = NULL;
1094         }
1095 }
1096
1097 /*
1098  * work queue call back to submit previously compressed pages
1099  */
1100 static noinline void async_cow_submit(struct btrfs_work *work)
1101 {
1102         struct async_cow *async_cow;
1103         struct btrfs_root *root;
1104         unsigned long nr_pages;
1105
1106         async_cow = container_of(work, struct async_cow, work);
1107
1108         root = async_cow->root;
1109         nr_pages = (async_cow->end - async_cow->start + PAGE_SIZE) >>
1110                 PAGE_SHIFT;
1111
1112         /*
1113          * atomic_sub_return implies a barrier for waitqueue_active
1114          */
1115         if (atomic_sub_return(nr_pages, &root->fs_info->async_delalloc_pages) <
1116             5 * SZ_1M &&
1117             waitqueue_active(&root->fs_info->async_submit_wait))
1118                 wake_up(&root->fs_info->async_submit_wait);
1119
1120         if (async_cow->inode)
1121                 submit_compressed_extents(async_cow->inode, async_cow);
1122 }
1123
1124 static noinline void async_cow_free(struct btrfs_work *work)
1125 {
1126         struct async_cow *async_cow;
1127         async_cow = container_of(work, struct async_cow, work);
1128         if (async_cow->inode)
1129                 btrfs_add_delayed_iput(async_cow->inode);
1130         kfree(async_cow);
1131 }
1132
1133 static int cow_file_range_async(struct inode *inode, struct page *locked_page,
1134                                 u64 start, u64 end, int *page_started,
1135                                 unsigned long *nr_written)
1136 {
1137         struct async_cow *async_cow;
1138         struct btrfs_root *root = BTRFS_I(inode)->root;
1139         unsigned long nr_pages;
1140         u64 cur_end;
1141         int limit = 10 * SZ_1M;
1142
1143         clear_extent_bit(&BTRFS_I(inode)->io_tree, start, end, EXTENT_LOCKED,
1144                          1, 0, NULL, GFP_NOFS);
1145         while (start < end) {
1146                 async_cow = kmalloc(sizeof(*async_cow), GFP_NOFS);
1147                 BUG_ON(!async_cow); /* -ENOMEM */
1148                 async_cow->inode = igrab(inode);
1149                 async_cow->root = root;
1150                 async_cow->locked_page = locked_page;
1151                 async_cow->start = start;
1152
1153                 if (BTRFS_I(inode)->flags & BTRFS_INODE_NOCOMPRESS &&
1154                     !btrfs_test_opt(root, FORCE_COMPRESS))
1155                         cur_end = end;
1156                 else
1157                         cur_end = min(end, start + SZ_512K - 1);
1158
1159                 async_cow->end = cur_end;
1160                 INIT_LIST_HEAD(&async_cow->extents);
1161
1162                 btrfs_init_work(&async_cow->work,
1163                                 btrfs_delalloc_helper,
1164                                 async_cow_start, async_cow_submit,
1165                                 async_cow_free);
1166
1167                 nr_pages = (cur_end - start + PAGE_SIZE) >>
1168                         PAGE_SHIFT;
1169                 atomic_add(nr_pages, &root->fs_info->async_delalloc_pages);
1170
1171                 btrfs_queue_work(root->fs_info->delalloc_workers,
1172                                  &async_cow->work);
1173
1174                 if (atomic_read(&root->fs_info->async_delalloc_pages) > limit) {
1175                         wait_event(root->fs_info->async_submit_wait,
1176                            (atomic_read(&root->fs_info->async_delalloc_pages) <
1177                             limit));
1178                 }
1179
1180                 while (atomic_read(&root->fs_info->async_submit_draining) &&
1181                       atomic_read(&root->fs_info->async_delalloc_pages)) {
1182                         wait_event(root->fs_info->async_submit_wait,
1183                           (atomic_read(&root->fs_info->async_delalloc_pages) ==
1184                            0));
1185                 }
1186
1187                 *nr_written += nr_pages;
1188                 start = cur_end + 1;
1189         }
1190         *page_started = 1;
1191         return 0;
1192 }
1193
1194 static noinline int csum_exist_in_range(struct btrfs_root *root,
1195                                         u64 bytenr, u64 num_bytes)
1196 {
1197         int ret;
1198         struct btrfs_ordered_sum *sums;
1199         LIST_HEAD(list);
1200
1201         ret = btrfs_lookup_csums_range(root->fs_info->csum_root, bytenr,
1202                                        bytenr + num_bytes - 1, &list, 0);
1203         if (ret == 0 && list_empty(&list))
1204                 return 0;
1205
1206         while (!list_empty(&list)) {
1207                 sums = list_entry(list.next, struct btrfs_ordered_sum, list);
1208                 list_del(&sums->list);
1209                 kfree(sums);
1210         }
1211         return 1;
1212 }
1213
1214 /*
1215  * when nowcow writeback call back.  This checks for snapshots or COW copies
1216  * of the extents that exist in the file, and COWs the file as required.
1217  *
1218  * If no cow copies or snapshots exist, we write directly to the existing
1219  * blocks on disk
1220  */
1221 static noinline int run_delalloc_nocow(struct inode *inode,
1222                                        struct page *locked_page,
1223                               u64 start, u64 end, int *page_started, int force,
1224                               unsigned long *nr_written)
1225 {
1226         struct btrfs_root *root = BTRFS_I(inode)->root;
1227         struct btrfs_trans_handle *trans;
1228         struct extent_buffer *leaf;
1229         struct btrfs_path *path;
1230         struct btrfs_file_extent_item *fi;
1231         struct btrfs_key found_key;
1232         u64 cow_start;
1233         u64 cur_offset;
1234         u64 extent_end;
1235         u64 extent_offset;
1236         u64 disk_bytenr;
1237         u64 num_bytes;
1238         u64 disk_num_bytes;
1239         u64 ram_bytes;
1240         int extent_type;
1241         int ret, err;
1242         int type;
1243         int nocow;
1244         int check_prev = 1;
1245         bool nolock;
1246         u64 ino = btrfs_ino(inode);
1247
1248         path = btrfs_alloc_path();
1249         if (!path) {
1250                 extent_clear_unlock_delalloc(inode, start, end, locked_page,
1251                                              EXTENT_LOCKED | EXTENT_DELALLOC |
1252                                              EXTENT_DO_ACCOUNTING |
1253                                              EXTENT_DEFRAG, PAGE_UNLOCK |
1254                                              PAGE_CLEAR_DIRTY |
1255                                              PAGE_SET_WRITEBACK |
1256                                              PAGE_END_WRITEBACK);
1257                 return -ENOMEM;
1258         }
1259
1260         nolock = btrfs_is_free_space_inode(inode);
1261
1262         if (nolock)
1263                 trans = btrfs_join_transaction_nolock(root);
1264         else
1265                 trans = btrfs_join_transaction(root);
1266
1267         if (IS_ERR(trans)) {
1268                 extent_clear_unlock_delalloc(inode, start, end, locked_page,
1269                                              EXTENT_LOCKED | EXTENT_DELALLOC |
1270                                              EXTENT_DO_ACCOUNTING |
1271                                              EXTENT_DEFRAG, PAGE_UNLOCK |
1272                                              PAGE_CLEAR_DIRTY |
1273                                              PAGE_SET_WRITEBACK |
1274                                              PAGE_END_WRITEBACK);
1275                 btrfs_free_path(path);
1276                 return PTR_ERR(trans);
1277         }
1278
1279         trans->block_rsv = &root->fs_info->delalloc_block_rsv;
1280
1281         cow_start = (u64)-1;
1282         cur_offset = start;
1283         while (1) {
1284                 ret = btrfs_lookup_file_extent(trans, root, path, ino,
1285                                                cur_offset, 0);
1286                 if (ret < 0)
1287                         goto error;
1288                 if (ret > 0 && path->slots[0] > 0 && check_prev) {
1289                         leaf = path->nodes[0];
1290                         btrfs_item_key_to_cpu(leaf, &found_key,
1291                                               path->slots[0] - 1);
1292                         if (found_key.objectid == ino &&
1293                             found_key.type == BTRFS_EXTENT_DATA_KEY)
1294                                 path->slots[0]--;
1295                 }
1296                 check_prev = 0;
1297 next_slot:
1298                 leaf = path->nodes[0];
1299                 if (path->slots[0] >= btrfs_header_nritems(leaf)) {
1300                         ret = btrfs_next_leaf(root, path);
1301                         if (ret < 0)
1302                                 goto error;
1303                         if (ret > 0)
1304                                 break;
1305                         leaf = path->nodes[0];
1306                 }
1307
1308                 nocow = 0;
1309                 disk_bytenr = 0;
1310                 num_bytes = 0;
1311                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
1312
1313                 if (found_key.objectid > ino)
1314                         break;
1315                 if (WARN_ON_ONCE(found_key.objectid < ino) ||
1316                     found_key.type < BTRFS_EXTENT_DATA_KEY) {
1317                         path->slots[0]++;
1318                         goto next_slot;
1319                 }
1320                 if (found_key.type > BTRFS_EXTENT_DATA_KEY ||
1321                     found_key.offset > end)
1322                         break;
1323
1324                 if (found_key.offset > cur_offset) {
1325                         extent_end = found_key.offset;
1326                         extent_type = 0;
1327                         goto out_check;
1328                 }
1329
1330                 fi = btrfs_item_ptr(leaf, path->slots[0],
1331                                     struct btrfs_file_extent_item);
1332                 extent_type = btrfs_file_extent_type(leaf, fi);
1333
1334                 ram_bytes = btrfs_file_extent_ram_bytes(leaf, fi);
1335                 if (extent_type == BTRFS_FILE_EXTENT_REG ||
1336                     extent_type == BTRFS_FILE_EXTENT_PREALLOC) {
1337                         disk_bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
1338                         extent_offset = btrfs_file_extent_offset(leaf, fi);
1339                         extent_end = found_key.offset +
1340                                 btrfs_file_extent_num_bytes(leaf, fi);
1341                         disk_num_bytes =
1342                                 btrfs_file_extent_disk_num_bytes(leaf, fi);
1343                         if (extent_end <= start) {
1344                                 path->slots[0]++;
1345                                 goto next_slot;
1346                         }
1347                         if (disk_bytenr == 0)
1348                                 goto out_check;
1349                         if (btrfs_file_extent_compression(leaf, fi) ||
1350                             btrfs_file_extent_encryption(leaf, fi) ||
1351                             btrfs_file_extent_other_encoding(leaf, fi))
1352                                 goto out_check;
1353                         if (extent_type == BTRFS_FILE_EXTENT_REG && !force)
1354                                 goto out_check;
1355                         if (btrfs_extent_readonly(root, disk_bytenr))
1356                                 goto out_check;
1357                         if (btrfs_cross_ref_exist(trans, root, ino,
1358                                                   found_key.offset -
1359                                                   extent_offset, disk_bytenr))
1360                                 goto out_check;
1361                         disk_bytenr += extent_offset;
1362                         disk_bytenr += cur_offset - found_key.offset;
1363                         num_bytes = min(end + 1, extent_end) - cur_offset;
1364                         /*
1365                          * if there are pending snapshots for this root,
1366                          * we fall into common COW way.
1367                          */
1368                         if (!nolock) {
1369                                 err = btrfs_start_write_no_snapshoting(root);
1370                                 if (!err)
1371                                         goto out_check;
1372                         }
1373                         /*
1374                          * force cow if csum exists in the range.
1375                          * this ensure that csum for a given extent are
1376                          * either valid or do not exist.
1377                          */
1378                         if (csum_exist_in_range(root, disk_bytenr, num_bytes))
1379                                 goto out_check;
1380                         nocow = 1;
1381                 } else if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
1382                         extent_end = found_key.offset +
1383                                 btrfs_file_extent_inline_len(leaf,
1384                                                      path->slots[0], fi);
1385                         extent_end = ALIGN(extent_end, root->sectorsize);
1386                 } else {
1387                         BUG_ON(1);
1388                 }
1389 out_check:
1390                 if (extent_end <= start) {
1391                         path->slots[0]++;
1392                         if (!nolock && nocow)
1393                                 btrfs_end_write_no_snapshoting(root);
1394                         goto next_slot;
1395                 }
1396                 if (!nocow) {
1397                         if (cow_start == (u64)-1)
1398                                 cow_start = cur_offset;
1399                         cur_offset = extent_end;
1400                         if (cur_offset > end)
1401                                 break;
1402                         path->slots[0]++;
1403                         goto next_slot;
1404                 }
1405
1406                 btrfs_release_path(path);
1407                 if (cow_start != (u64)-1) {
1408                         ret = cow_file_range(inode, locked_page,
1409                                              cow_start, found_key.offset - 1,
1410                                              page_started, nr_written, 1);
1411                         if (ret) {
1412                                 if (!nolock && nocow)
1413                                         btrfs_end_write_no_snapshoting(root);
1414                                 goto error;
1415                         }
1416                         cow_start = (u64)-1;
1417                 }
1418
1419                 if (extent_type == BTRFS_FILE_EXTENT_PREALLOC) {
1420                         struct extent_map *em;
1421                         struct extent_map_tree *em_tree;
1422                         em_tree = &BTRFS_I(inode)->extent_tree;
1423                         em = alloc_extent_map();
1424                         BUG_ON(!em); /* -ENOMEM */
1425                         em->start = cur_offset;
1426                         em->orig_start = found_key.offset - extent_offset;
1427                         em->len = num_bytes;
1428                         em->block_len = num_bytes;
1429                         em->block_start = disk_bytenr;
1430                         em->orig_block_len = disk_num_bytes;
1431                         em->ram_bytes = ram_bytes;
1432                         em->bdev = root->fs_info->fs_devices->latest_bdev;
1433                         em->mod_start = em->start;
1434                         em->mod_len = em->len;
1435                         set_bit(EXTENT_FLAG_PINNED, &em->flags);
1436                         set_bit(EXTENT_FLAG_FILLING, &em->flags);
1437                         em->generation = -1;
1438                         while (1) {
1439                                 write_lock(&em_tree->lock);
1440                                 ret = add_extent_mapping(em_tree, em, 1);
1441                                 write_unlock(&em_tree->lock);
1442                                 if (ret != -EEXIST) {
1443                                         free_extent_map(em);
1444                                         break;
1445                                 }
1446                                 btrfs_drop_extent_cache(inode, em->start,
1447                                                 em->start + em->len - 1, 0);
1448                         }
1449                         type = BTRFS_ORDERED_PREALLOC;
1450                 } else {
1451                         type = BTRFS_ORDERED_NOCOW;
1452                 }
1453
1454                 ret = btrfs_add_ordered_extent(inode, cur_offset, disk_bytenr,
1455                                                num_bytes, num_bytes, type);
1456                 BUG_ON(ret); /* -ENOMEM */
1457
1458                 if (root->root_key.objectid ==
1459                     BTRFS_DATA_RELOC_TREE_OBJECTID) {
1460                         ret = btrfs_reloc_clone_csums(inode, cur_offset,
1461                                                       num_bytes);
1462                         if (ret) {
1463                                 if (!nolock && nocow)
1464                                         btrfs_end_write_no_snapshoting(root);
1465                                 goto error;
1466                         }
1467                 }
1468
1469                 extent_clear_unlock_delalloc(inode, cur_offset,
1470                                              cur_offset + num_bytes - 1,
1471                                              locked_page, EXTENT_LOCKED |
1472                                              EXTENT_DELALLOC, PAGE_UNLOCK |
1473                                              PAGE_SET_PRIVATE2);
1474                 if (!nolock && nocow)
1475                         btrfs_end_write_no_snapshoting(root);
1476                 cur_offset = extent_end;
1477                 if (cur_offset > end)
1478                         break;
1479         }
1480         btrfs_release_path(path);
1481
1482         if (cur_offset <= end && cow_start == (u64)-1) {
1483                 cow_start = cur_offset;
1484                 cur_offset = end;
1485         }
1486
1487         if (cow_start != (u64)-1) {
1488                 ret = cow_file_range(inode, locked_page, cow_start, end,
1489                                      page_started, nr_written, 1);
1490                 if (ret)
1491                         goto error;
1492         }
1493
1494 error:
1495         err = btrfs_end_transaction(trans, root);
1496         if (!ret)
1497                 ret = err;
1498
1499         if (ret && cur_offset < end)
1500                 extent_clear_unlock_delalloc(inode, cur_offset, end,
1501                                              locked_page, EXTENT_LOCKED |
1502                                              EXTENT_DELALLOC | EXTENT_DEFRAG |
1503                                              EXTENT_DO_ACCOUNTING, PAGE_UNLOCK |
1504                                              PAGE_CLEAR_DIRTY |
1505                                              PAGE_SET_WRITEBACK |
1506                                              PAGE_END_WRITEBACK);
1507         btrfs_free_path(path);
1508         return ret;
1509 }
1510
1511 static inline int need_force_cow(struct inode *inode, u64 start, u64 end)
1512 {
1513
1514         if (!(BTRFS_I(inode)->flags & BTRFS_INODE_NODATACOW) &&
1515             !(BTRFS_I(inode)->flags & BTRFS_INODE_PREALLOC))
1516                 return 0;
1517
1518         /*
1519          * @defrag_bytes is a hint value, no spinlock held here,
1520          * if is not zero, it means the file is defragging.
1521          * Force cow if given extent needs to be defragged.
1522          */
1523         if (BTRFS_I(inode)->defrag_bytes &&
1524             test_range_bit(&BTRFS_I(inode)->io_tree, start, end,
1525                            EXTENT_DEFRAG, 0, NULL))
1526                 return 1;
1527
1528         return 0;
1529 }
1530
1531 /*
1532  * extent_io.c call back to do delayed allocation processing
1533  */
1534 static int run_delalloc_range(struct inode *inode, struct page *locked_page,
1535                               u64 start, u64 end, int *page_started,
1536                               unsigned long *nr_written)
1537 {
1538         int ret;
1539         int force_cow = need_force_cow(inode, start, end);
1540
1541         if (BTRFS_I(inode)->flags & BTRFS_INODE_NODATACOW && !force_cow) {
1542                 ret = run_delalloc_nocow(inode, locked_page, start, end,
1543                                          page_started, 1, nr_written);
1544         } else if (BTRFS_I(inode)->flags & BTRFS_INODE_PREALLOC && !force_cow) {
1545                 ret = run_delalloc_nocow(inode, locked_page, start, end,
1546                                          page_started, 0, nr_written);
1547         } else if (!inode_need_compress(inode)) {
1548                 ret = cow_file_range(inode, locked_page, start, end,
1549                                       page_started, nr_written, 1);
1550         } else {
1551                 set_bit(BTRFS_INODE_HAS_ASYNC_EXTENT,
1552                         &BTRFS_I(inode)->runtime_flags);
1553                 ret = cow_file_range_async(inode, locked_page, start, end,
1554                                            page_started, nr_written);
1555         }
1556         return ret;
1557 }
1558
1559 static void btrfs_split_extent_hook(struct inode *inode,
1560                                     struct extent_state *orig, u64 split)
1561 {
1562         u64 size;
1563
1564         /* not delalloc, ignore it */
1565         if (!(orig->state & EXTENT_DELALLOC))
1566                 return;
1567
1568         size = orig->end - orig->start + 1;
1569         if (size > BTRFS_MAX_EXTENT_SIZE) {
1570                 u64 num_extents;
1571                 u64 new_size;
1572
1573                 /*
1574                  * See the explanation in btrfs_merge_extent_hook, the same
1575                  * applies here, just in reverse.
1576                  */
1577                 new_size = orig->end - split + 1;
1578                 num_extents = div64_u64(new_size + BTRFS_MAX_EXTENT_SIZE - 1,
1579                                         BTRFS_MAX_EXTENT_SIZE);
1580                 new_size = split - orig->start;
1581                 num_extents += div64_u64(new_size + BTRFS_MAX_EXTENT_SIZE - 1,
1582                                         BTRFS_MAX_EXTENT_SIZE);
1583                 if (div64_u64(size + BTRFS_MAX_EXTENT_SIZE - 1,
1584                               BTRFS_MAX_EXTENT_SIZE) >= num_extents)
1585                         return;
1586         }
1587
1588         spin_lock(&BTRFS_I(inode)->lock);
1589         BTRFS_I(inode)->outstanding_extents++;
1590         spin_unlock(&BTRFS_I(inode)->lock);
1591 }
1592
1593 /*
1594  * extent_io.c merge_extent_hook, used to track merged delayed allocation
1595  * extents so we can keep track of new extents that are just merged onto old
1596  * extents, such as when we are doing sequential writes, so we can properly
1597  * account for the metadata space we'll need.
1598  */
1599 static void btrfs_merge_extent_hook(struct inode *inode,
1600                                     struct extent_state *new,
1601                                     struct extent_state *other)
1602 {
1603         u64 new_size, old_size;
1604         u64 num_extents;
1605
1606         /* not delalloc, ignore it */
1607         if (!(other->state & EXTENT_DELALLOC))
1608                 return;
1609
1610         if (new->start > other->start)
1611                 new_size = new->end - other->start + 1;
1612         else
1613                 new_size = other->end - new->start + 1;
1614
1615         /* we're not bigger than the max, unreserve the space and go */
1616         if (new_size <= BTRFS_MAX_EXTENT_SIZE) {
1617                 spin_lock(&BTRFS_I(inode)->lock);
1618                 BTRFS_I(inode)->outstanding_extents--;
1619                 spin_unlock(&BTRFS_I(inode)->lock);
1620                 return;
1621         }
1622
1623         /*
1624          * We have to add up either side to figure out how many extents were
1625          * accounted for before we merged into one big extent.  If the number of
1626          * extents we accounted for is <= the amount we need for the new range
1627          * then we can return, otherwise drop.  Think of it like this
1628          *
1629          * [ 4k][MAX_SIZE]
1630          *
1631          * So we've grown the extent by a MAX_SIZE extent, this would mean we
1632          * need 2 outstanding extents, on one side we have 1 and the other side
1633          * we have 1 so they are == and we can return.  But in this case
1634          *
1635          * [MAX_SIZE+4k][MAX_SIZE+4k]
1636          *
1637          * Each range on their own accounts for 2 extents, but merged together
1638          * they are only 3 extents worth of accounting, so we need to drop in
1639          * this case.
1640          */
1641         old_size = other->end - other->start + 1;
1642         num_extents = div64_u64(old_size + BTRFS_MAX_EXTENT_SIZE - 1,
1643                                 BTRFS_MAX_EXTENT_SIZE);
1644         old_size = new->end - new->start + 1;
1645         num_extents += div64_u64(old_size + BTRFS_MAX_EXTENT_SIZE - 1,
1646                                  BTRFS_MAX_EXTENT_SIZE);
1647
1648         if (div64_u64(new_size + BTRFS_MAX_EXTENT_SIZE - 1,
1649                       BTRFS_MAX_EXTENT_SIZE) >= num_extents)
1650                 return;
1651
1652         spin_lock(&BTRFS_I(inode)->lock);
1653         BTRFS_I(inode)->outstanding_extents--;
1654         spin_unlock(&BTRFS_I(inode)->lock);
1655 }
1656
1657 static void btrfs_add_delalloc_inodes(struct btrfs_root *root,
1658                                       struct inode *inode)
1659 {
1660         spin_lock(&root->delalloc_lock);
1661         if (list_empty(&BTRFS_I(inode)->delalloc_inodes)) {
1662                 list_add_tail(&BTRFS_I(inode)->delalloc_inodes,
1663                               &root->delalloc_inodes);
1664                 set_bit(BTRFS_INODE_IN_DELALLOC_LIST,
1665                         &BTRFS_I(inode)->runtime_flags);
1666                 root->nr_delalloc_inodes++;
1667                 if (root->nr_delalloc_inodes == 1) {
1668                         spin_lock(&root->fs_info->delalloc_root_lock);
1669                         BUG_ON(!list_empty(&root->delalloc_root));
1670                         list_add_tail(&root->delalloc_root,
1671                                       &root->fs_info->delalloc_roots);
1672                         spin_unlock(&root->fs_info->delalloc_root_lock);
1673                 }
1674         }
1675         spin_unlock(&root->delalloc_lock);
1676 }
1677
1678 static void btrfs_del_delalloc_inode(struct btrfs_root *root,
1679                                      struct inode *inode)
1680 {
1681         spin_lock(&root->delalloc_lock);
1682         if (!list_empty(&BTRFS_I(inode)->delalloc_inodes)) {
1683                 list_del_init(&BTRFS_I(inode)->delalloc_inodes);
1684                 clear_bit(BTRFS_INODE_IN_DELALLOC_LIST,
1685                           &BTRFS_I(inode)->runtime_flags);
1686                 root->nr_delalloc_inodes--;
1687                 if (!root->nr_delalloc_inodes) {
1688                         spin_lock(&root->fs_info->delalloc_root_lock);
1689                         BUG_ON(list_empty(&root->delalloc_root));
1690                         list_del_init(&root->delalloc_root);
1691                         spin_unlock(&root->fs_info->delalloc_root_lock);
1692                 }
1693         }
1694         spin_unlock(&root->delalloc_lock);
1695 }
1696
1697 /*
1698  * extent_io.c set_bit_hook, used to track delayed allocation
1699  * bytes in this file, and to maintain the list of inodes that
1700  * have pending delalloc work to be done.
1701  */
1702 static void btrfs_set_bit_hook(struct inode *inode,
1703                                struct extent_state *state, unsigned *bits)
1704 {
1705
1706         if ((*bits & EXTENT_DEFRAG) && !(*bits & EXTENT_DELALLOC))
1707                 WARN_ON(1);
1708         /*
1709          * set_bit and clear bit hooks normally require _irqsave/restore
1710          * but in this case, we are only testing for the DELALLOC
1711          * bit, which is only set or cleared with irqs on
1712          */
1713         if (!(state->state & EXTENT_DELALLOC) && (*bits & EXTENT_DELALLOC)) {
1714                 struct btrfs_root *root = BTRFS_I(inode)->root;
1715                 u64 len = state->end + 1 - state->start;
1716                 bool do_list = !btrfs_is_free_space_inode(inode);
1717
1718                 if (*bits & EXTENT_FIRST_DELALLOC) {
1719                         *bits &= ~EXTENT_FIRST_DELALLOC;
1720                 } else {
1721                         spin_lock(&BTRFS_I(inode)->lock);
1722                         BTRFS_I(inode)->outstanding_extents++;
1723                         spin_unlock(&BTRFS_I(inode)->lock);
1724                 }
1725
1726                 /* For sanity tests */
1727                 if (btrfs_test_is_dummy_root(root))
1728                         return;
1729
1730                 __percpu_counter_add(&root->fs_info->delalloc_bytes, len,
1731                                      root->fs_info->delalloc_batch);
1732                 spin_lock(&BTRFS_I(inode)->lock);
1733                 BTRFS_I(inode)->delalloc_bytes += len;
1734                 if (*bits & EXTENT_DEFRAG)
1735                         BTRFS_I(inode)->defrag_bytes += len;
1736                 if (do_list && !test_bit(BTRFS_INODE_IN_DELALLOC_LIST,
1737                                          &BTRFS_I(inode)->runtime_flags))
1738                         btrfs_add_delalloc_inodes(root, inode);
1739                 spin_unlock(&BTRFS_I(inode)->lock);
1740         }
1741 }
1742
1743 /*
1744  * extent_io.c clear_bit_hook, see set_bit_hook for why
1745  */
1746 static void btrfs_clear_bit_hook(struct inode *inode,
1747                                  struct extent_state *state,
1748                                  unsigned *bits)
1749 {
1750         u64 len = state->end + 1 - state->start;
1751         u64 num_extents = div64_u64(len + BTRFS_MAX_EXTENT_SIZE -1,
1752                                     BTRFS_MAX_EXTENT_SIZE);
1753
1754         spin_lock(&BTRFS_I(inode)->lock);
1755         if ((state->state & EXTENT_DEFRAG) && (*bits & EXTENT_DEFRAG))
1756                 BTRFS_I(inode)->defrag_bytes -= len;
1757         spin_unlock(&BTRFS_I(inode)->lock);
1758
1759         /*
1760          * set_bit and clear bit hooks normally require _irqsave/restore
1761          * but in this case, we are only testing for the DELALLOC
1762          * bit, which is only set or cleared with irqs on
1763          */
1764         if ((state->state & EXTENT_DELALLOC) && (*bits & EXTENT_DELALLOC)) {
1765                 struct btrfs_root *root = BTRFS_I(inode)->root;
1766                 bool do_list = !btrfs_is_free_space_inode(inode);
1767
1768                 if (*bits & EXTENT_FIRST_DELALLOC) {
1769                         *bits &= ~EXTENT_FIRST_DELALLOC;
1770                 } else if (!(*bits & EXTENT_DO_ACCOUNTING)) {
1771                         spin_lock(&BTRFS_I(inode)->lock);
1772                         BTRFS_I(inode)->outstanding_extents -= num_extents;
1773                         spin_unlock(&BTRFS_I(inode)->lock);
1774                 }
1775
1776                 /*
1777                  * We don't reserve metadata space for space cache inodes so we
1778                  * don't need to call dellalloc_release_metadata if there is an
1779                  * error.
1780                  */
1781                 if (*bits & EXTENT_DO_ACCOUNTING &&
1782                     root != root->fs_info->tree_root)
1783                         btrfs_delalloc_release_metadata(inode, len);
1784
1785                 /* For sanity tests. */
1786                 if (btrfs_test_is_dummy_root(root))
1787                         return;
1788
1789                 if (root->root_key.objectid != BTRFS_DATA_RELOC_TREE_OBJECTID
1790                     && do_list && !(state->state & EXTENT_NORESERVE))
1791                         btrfs_free_reserved_data_space_noquota(inode,
1792                                         state->start, len);
1793
1794                 __percpu_counter_add(&root->fs_info->delalloc_bytes, -len,
1795                                      root->fs_info->delalloc_batch);
1796                 spin_lock(&BTRFS_I(inode)->lock);
1797                 BTRFS_I(inode)->delalloc_bytes -= len;
1798                 if (do_list && BTRFS_I(inode)->delalloc_bytes == 0 &&
1799                     test_bit(BTRFS_INODE_IN_DELALLOC_LIST,
1800                              &BTRFS_I(inode)->runtime_flags))
1801                         btrfs_del_delalloc_inode(root, inode);
1802                 spin_unlock(&BTRFS_I(inode)->lock);
1803         }
1804 }
1805
1806 /*
1807  * extent_io.c merge_bio_hook, this must check the chunk tree to make sure
1808  * we don't create bios that span stripes or chunks
1809  */
1810 int btrfs_merge_bio_hook(int rw, struct page *page, unsigned long offset,
1811                          size_t size, struct bio *bio,
1812                          unsigned long bio_flags)
1813 {
1814         struct btrfs_root *root = BTRFS_I(page->mapping->host)->root;
1815         u64 logical = (u64)bio->bi_iter.bi_sector << 9;
1816         u64 length = 0;
1817         u64 map_length;
1818         int ret;
1819
1820         if (bio_flags & EXTENT_BIO_COMPRESSED)
1821                 return 0;
1822
1823         length = bio->bi_iter.bi_size;
1824         map_length = length;
1825         ret = btrfs_map_block(root->fs_info, rw, logical,
1826                               &map_length, NULL, 0);
1827         /* Will always return 0 with map_multi == NULL */
1828         BUG_ON(ret < 0);
1829         if (map_length < length + size)
1830                 return 1;
1831         return 0;
1832 }
1833
1834 /*
1835  * in order to insert checksums into the metadata in large chunks,
1836  * we wait until bio submission time.   All the pages in the bio are
1837  * checksummed and sums are attached onto the ordered extent record.
1838  *
1839  * At IO completion time the cums attached on the ordered extent record
1840  * are inserted into the btree
1841  */
1842 static int __btrfs_submit_bio_start(struct inode *inode, int rw,
1843                                     struct bio *bio, int mirror_num,
1844                                     unsigned long bio_flags,
1845                                     u64 bio_offset)
1846 {
1847         struct btrfs_root *root = BTRFS_I(inode)->root;
1848         int ret = 0;
1849
1850         ret = btrfs_csum_one_bio(root, inode, bio, 0, 0);
1851         BUG_ON(ret); /* -ENOMEM */
1852         return 0;
1853 }
1854
1855 /*
1856  * in order to insert checksums into the metadata in large chunks,
1857  * we wait until bio submission time.   All the pages in the bio are
1858  * checksummed and sums are attached onto the ordered extent record.
1859  *
1860  * At IO completion time the cums attached on the ordered extent record
1861  * are inserted into the btree
1862  */
1863 static int __btrfs_submit_bio_done(struct inode *inode, int rw, struct bio *bio,
1864                           int mirror_num, unsigned long bio_flags,
1865                           u64 bio_offset)
1866 {
1867         struct btrfs_root *root = BTRFS_I(inode)->root;
1868         int ret;
1869
1870         ret = btrfs_map_bio(root, rw, bio, mirror_num, 1);
1871         if (ret) {
1872                 bio->bi_error = ret;
1873                 bio_endio(bio);
1874         }
1875         return ret;
1876 }
1877
1878 /*
1879  * extent_io.c submission hook. This does the right thing for csum calculation
1880  * on write, or reading the csums from the tree before a read
1881  */
1882 static int btrfs_submit_bio_hook(struct inode *inode, int rw, struct bio *bio,
1883                           int mirror_num, unsigned long bio_flags,
1884                           u64 bio_offset)
1885 {
1886         struct btrfs_root *root = BTRFS_I(inode)->root;
1887         enum btrfs_wq_endio_type metadata = BTRFS_WQ_ENDIO_DATA;
1888         int ret = 0;
1889         int skip_sum;
1890         int async = !atomic_read(&BTRFS_I(inode)->sync_writers);
1891
1892         skip_sum = BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM;
1893
1894         if (btrfs_is_free_space_inode(inode))
1895                 metadata = BTRFS_WQ_ENDIO_FREE_SPACE;
1896
1897         if (!(rw & REQ_WRITE)) {
1898                 ret = btrfs_bio_wq_end_io(root->fs_info, bio, metadata);
1899                 if (ret)
1900                         goto out;
1901
1902                 if (bio_flags & EXTENT_BIO_COMPRESSED) {
1903                         ret = btrfs_submit_compressed_read(inode, bio,
1904                                                            mirror_num,
1905                                                            bio_flags);
1906                         goto out;
1907                 } else if (!skip_sum) {
1908                         ret = btrfs_lookup_bio_sums(root, inode, bio, NULL);
1909                         if (ret)
1910                                 goto out;
1911                 }
1912                 goto mapit;
1913         } else if (async && !skip_sum) {
1914                 /* csum items have already been cloned */
1915                 if (root->root_key.objectid == BTRFS_DATA_RELOC_TREE_OBJECTID)
1916                         goto mapit;
1917                 /* we're doing a write, do the async checksumming */
1918                 ret = btrfs_wq_submit_bio(BTRFS_I(inode)->root->fs_info,
1919                                    inode, rw, bio, mirror_num,
1920                                    bio_flags, bio_offset,
1921                                    __btrfs_submit_bio_start,
1922                                    __btrfs_submit_bio_done);
1923                 goto out;
1924         } else if (!skip_sum) {
1925                 ret = btrfs_csum_one_bio(root, inode, bio, 0, 0);
1926                 if (ret)
1927                         goto out;
1928         }
1929
1930 mapit:
1931         ret = btrfs_map_bio(root, rw, bio, mirror_num, 0);
1932
1933 out:
1934         if (ret < 0) {
1935                 bio->bi_error = ret;
1936                 bio_endio(bio);
1937         }
1938         return ret;
1939 }
1940
1941 /*
1942  * given a list of ordered sums record them in the inode.  This happens
1943  * at IO completion time based on sums calculated at bio submission time.
1944  */
1945 static noinline int add_pending_csums(struct btrfs_trans_handle *trans,
1946                              struct inode *inode, u64 file_offset,
1947                              struct list_head *list)
1948 {
1949         struct btrfs_ordered_sum *sum;
1950
1951         list_for_each_entry(sum, list, list) {
1952                 trans->adding_csums = 1;
1953                 btrfs_csum_file_blocks(trans,
1954                        BTRFS_I(inode)->root->fs_info->csum_root, sum);
1955                 trans->adding_csums = 0;
1956         }
1957         return 0;
1958 }
1959
1960 int btrfs_set_extent_delalloc(struct inode *inode, u64 start, u64 end,
1961                               struct extent_state **cached_state)
1962 {
1963         WARN_ON((end & (PAGE_SIZE - 1)) == 0);
1964         return set_extent_delalloc(&BTRFS_I(inode)->io_tree, start, end,
1965                                    cached_state, GFP_NOFS);
1966 }
1967
1968 /* see btrfs_writepage_start_hook for details on why this is required */
1969 struct btrfs_writepage_fixup {
1970         struct page *page;
1971         struct btrfs_work work;
1972 };
1973
1974 static void btrfs_writepage_fixup_worker(struct btrfs_work *work)
1975 {
1976         struct btrfs_writepage_fixup *fixup;
1977         struct btrfs_ordered_extent *ordered;
1978         struct extent_state *cached_state = NULL;
1979         struct page *page;
1980         struct inode *inode;
1981         u64 page_start;
1982         u64 page_end;
1983         int ret;
1984
1985         fixup = container_of(work, struct btrfs_writepage_fixup, work);
1986         page = fixup->page;
1987 again:
1988         lock_page(page);
1989         if (!page->mapping || !PageDirty(page) || !PageChecked(page)) {
1990                 ClearPageChecked(page);
1991                 goto out_page;
1992         }
1993
1994         inode = page->mapping->host;
1995         page_start = page_offset(page);
1996         page_end = page_offset(page) + PAGE_SIZE - 1;
1997
1998         lock_extent_bits(&BTRFS_I(inode)->io_tree, page_start, page_end,
1999                          &cached_state);
2000
2001         /* already ordered? We're done */
2002         if (PagePrivate2(page))
2003                 goto out;
2004
2005         ordered = btrfs_lookup_ordered_range(inode, page_start,
2006                                         PAGE_SIZE);
2007         if (ordered) {
2008                 unlock_extent_cached(&BTRFS_I(inode)->io_tree, page_start,
2009                                      page_end, &cached_state, GFP_NOFS);
2010                 unlock_page(page);
2011                 btrfs_start_ordered_extent(inode, ordered, 1);
2012                 btrfs_put_ordered_extent(ordered);
2013                 goto again;
2014         }
2015
2016         ret = btrfs_delalloc_reserve_space(inode, page_start,
2017                                            PAGE_SIZE);
2018         if (ret) {
2019                 mapping_set_error(page->mapping, ret);
2020                 end_extent_writepage(page, ret, page_start, page_end);
2021                 ClearPageChecked(page);
2022                 goto out;
2023          }
2024
2025         btrfs_set_extent_delalloc(inode, page_start, page_end, &cached_state);
2026         ClearPageChecked(page);
2027         set_page_dirty(page);
2028 out:
2029         unlock_extent_cached(&BTRFS_I(inode)->io_tree, page_start, page_end,
2030                              &cached_state, GFP_NOFS);
2031 out_page:
2032         unlock_page(page);
2033         put_page(page);
2034         kfree(fixup);
2035 }
2036
2037 /*
2038  * There are a few paths in the higher layers of the kernel that directly
2039  * set the page dirty bit without asking the filesystem if it is a
2040  * good idea.  This causes problems because we want to make sure COW
2041  * properly happens and the data=ordered rules are followed.
2042  *
2043  * In our case any range that doesn't have the ORDERED bit set
2044  * hasn't been properly setup for IO.  We kick off an async process
2045  * to fix it up.  The async helper will wait for ordered extents, set
2046  * the delalloc bit and make it safe to write the page.
2047  */
2048 static int btrfs_writepage_start_hook(struct page *page, u64 start, u64 end)
2049 {
2050         struct inode *inode = page->mapping->host;
2051         struct btrfs_writepage_fixup *fixup;
2052         struct btrfs_root *root = BTRFS_I(inode)->root;
2053
2054         /* this page is properly in the ordered list */
2055         if (TestClearPagePrivate2(page))
2056                 return 0;
2057
2058         if (PageChecked(page))
2059                 return -EAGAIN;
2060
2061         fixup = kzalloc(sizeof(*fixup), GFP_NOFS);
2062         if (!fixup)
2063                 return -EAGAIN;
2064
2065         SetPageChecked(page);
2066         get_page(page);
2067         btrfs_init_work(&fixup->work, btrfs_fixup_helper,
2068                         btrfs_writepage_fixup_worker, NULL, NULL);
2069         fixup->page = page;
2070         btrfs_queue_work(root->fs_info->fixup_workers, &fixup->work);
2071         return -EBUSY;
2072 }
2073
2074 static int insert_reserved_file_extent(struct btrfs_trans_handle *trans,
2075                                        struct inode *inode, u64 file_pos,
2076                                        u64 disk_bytenr, u64 disk_num_bytes,
2077                                        u64 num_bytes, u64 ram_bytes,
2078                                        u8 compression, u8 encryption,
2079                                        u16 other_encoding, int extent_type)
2080 {
2081         struct btrfs_root *root = BTRFS_I(inode)->root;
2082         struct btrfs_file_extent_item *fi;
2083         struct btrfs_path *path;
2084         struct extent_buffer *leaf;
2085         struct btrfs_key ins;
2086         int extent_inserted = 0;
2087         int ret;
2088
2089         path = btrfs_alloc_path();
2090         if (!path)
2091                 return -ENOMEM;
2092
2093         /*
2094          * we may be replacing one extent in the tree with another.
2095          * The new extent is pinned in the extent map, and we don't want
2096          * to drop it from the cache until it is completely in the btree.
2097          *
2098          * So, tell btrfs_drop_extents to leave this extent in the cache.
2099          * the caller is expected to unpin it and allow it to be merged
2100          * with the others.
2101          */
2102         ret = __btrfs_drop_extents(trans, root, inode, path, file_pos,
2103                                    file_pos + num_bytes, NULL, 0,
2104                                    1, sizeof(*fi), &extent_inserted);
2105         if (ret)
2106                 goto out;
2107
2108         if (!extent_inserted) {
2109                 ins.objectid = btrfs_ino(inode);
2110                 ins.offset = file_pos;
2111                 ins.type = BTRFS_EXTENT_DATA_KEY;
2112
2113                 path->leave_spinning = 1;
2114                 ret = btrfs_insert_empty_item(trans, root, path, &ins,
2115                                               sizeof(*fi));
2116                 if (ret)
2117                         goto out;
2118         }
2119         leaf = path->nodes[0];
2120         fi = btrfs_item_ptr(leaf, path->slots[0],
2121                             struct btrfs_file_extent_item);
2122         btrfs_set_file_extent_generation(leaf, fi, trans->transid);
2123         btrfs_set_file_extent_type(leaf, fi, extent_type);
2124         btrfs_set_file_extent_disk_bytenr(leaf, fi, disk_bytenr);
2125         btrfs_set_file_extent_disk_num_bytes(leaf, fi, disk_num_bytes);
2126         btrfs_set_file_extent_offset(leaf, fi, 0);
2127         btrfs_set_file_extent_num_bytes(leaf, fi, num_bytes);
2128         btrfs_set_file_extent_ram_bytes(leaf, fi, ram_bytes);
2129         btrfs_set_file_extent_compression(leaf, fi, compression);
2130         btrfs_set_file_extent_encryption(leaf, fi, encryption);
2131         btrfs_set_file_extent_other_encoding(leaf, fi, other_encoding);
2132
2133         btrfs_mark_buffer_dirty(leaf);
2134         btrfs_release_path(path);
2135
2136         inode_add_bytes(inode, num_bytes);
2137
2138         ins.objectid = disk_bytenr;
2139         ins.offset = disk_num_bytes;
2140         ins.type = BTRFS_EXTENT_ITEM_KEY;
2141         ret = btrfs_alloc_reserved_file_extent(trans, root,
2142                                         root->root_key.objectid,
2143                                         btrfs_ino(inode), file_pos,
2144                                         ram_bytes, &ins);
2145         /*
2146          * Release the reserved range from inode dirty range map, as it is
2147          * already moved into delayed_ref_head
2148          */
2149         btrfs_qgroup_release_data(inode, file_pos, ram_bytes);
2150 out:
2151         btrfs_free_path(path);
2152
2153         return ret;
2154 }
2155
2156 /* snapshot-aware defrag */
2157 struct sa_defrag_extent_backref {
2158         struct rb_node node;
2159         struct old_sa_defrag_extent *old;
2160         u64 root_id;
2161         u64 inum;
2162         u64 file_pos;
2163         u64 extent_offset;
2164         u64 num_bytes;
2165         u64 generation;
2166 };
2167
2168 struct old_sa_defrag_extent {
2169         struct list_head list;
2170         struct new_sa_defrag_extent *new;
2171
2172         u64 extent_offset;
2173         u64 bytenr;
2174         u64 offset;
2175         u64 len;
2176         int count;
2177 };
2178
2179 struct new_sa_defrag_extent {
2180         struct rb_root root;
2181         struct list_head head;
2182         struct btrfs_path *path;
2183         struct inode *inode;
2184         u64 file_pos;
2185         u64 len;
2186         u64 bytenr;
2187         u64 disk_len;
2188         u8 compress_type;
2189 };
2190
2191 static int backref_comp(struct sa_defrag_extent_backref *b1,
2192                         struct sa_defrag_extent_backref *b2)
2193 {
2194         if (b1->root_id < b2->root_id)
2195                 return -1;
2196         else if (b1->root_id > b2->root_id)
2197                 return 1;
2198
2199         if (b1->inum < b2->inum)
2200                 return -1;
2201         else if (b1->inum > b2->inum)
2202                 return 1;
2203
2204         if (b1->file_pos < b2->file_pos)
2205                 return -1;
2206         else if (b1->file_pos > b2->file_pos)
2207                 return 1;
2208
2209         /*
2210          * [------------------------------] ===> (a range of space)
2211          *     |<--->|   |<---->| =============> (fs/file tree A)
2212          * |<---------------------------->| ===> (fs/file tree B)
2213          *
2214          * A range of space can refer to two file extents in one tree while
2215          * refer to only one file extent in another tree.
2216          *
2217          * So we may process a disk offset more than one time(two extents in A)
2218          * and locate at the same extent(one extent in B), then insert two same
2219          * backrefs(both refer to the extent in B).
2220          */
2221         return 0;
2222 }
2223
2224 static void backref_insert(struct rb_root *root,
2225                            struct sa_defrag_extent_backref *backref)
2226 {
2227         struct rb_node **p = &root->rb_node;
2228         struct rb_node *parent = NULL;
2229         struct sa_defrag_extent_backref *entry;
2230         int ret;
2231
2232         while (*p) {
2233                 parent = *p;
2234                 entry = rb_entry(parent, struct sa_defrag_extent_backref, node);
2235
2236                 ret = backref_comp(backref, entry);
2237                 if (ret < 0)
2238                         p = &(*p)->rb_left;
2239                 else
2240                         p = &(*p)->rb_right;
2241         }
2242
2243         rb_link_node(&backref->node, parent, p);
2244         rb_insert_color(&backref->node, root);
2245 }
2246
2247 /*
2248  * Note the backref might has changed, and in this case we just return 0.
2249  */
2250 static noinline int record_one_backref(u64 inum, u64 offset, u64 root_id,
2251                                        void *ctx)
2252 {
2253         struct btrfs_file_extent_item *extent;
2254         struct btrfs_fs_info *fs_info;
2255         struct old_sa_defrag_extent *old = ctx;
2256         struct new_sa_defrag_extent *new = old->new;
2257         struct btrfs_path *path = new->path;
2258         struct btrfs_key key;
2259         struct btrfs_root *root;
2260         struct sa_defrag_extent_backref *backref;
2261         struct extent_buffer *leaf;
2262         struct inode *inode = new->inode;
2263         int slot;
2264         int ret;
2265         u64 extent_offset;
2266         u64 num_bytes;
2267
2268         if (BTRFS_I(inode)->root->root_key.objectid == root_id &&
2269             inum == btrfs_ino(inode))
2270                 return 0;
2271
2272         key.objectid = root_id;
2273         key.type = BTRFS_ROOT_ITEM_KEY;
2274         key.offset = (u64)-1;
2275
2276         fs_info = BTRFS_I(inode)->root->fs_info;
2277         root = btrfs_read_fs_root_no_name(fs_info, &key);
2278         if (IS_ERR(root)) {
2279                 if (PTR_ERR(root) == -ENOENT)
2280                         return 0;
2281                 WARN_ON(1);
2282                 pr_debug("inum=%llu, offset=%llu, root_id=%llu\n",
2283                          inum, offset, root_id);
2284                 return PTR_ERR(root);
2285         }
2286
2287         key.objectid = inum;
2288         key.type = BTRFS_EXTENT_DATA_KEY;
2289         if (offset > (u64)-1 << 32)
2290                 key.offset = 0;
2291         else
2292                 key.offset = offset;
2293
2294         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
2295         if (WARN_ON(ret < 0))
2296                 return ret;
2297         ret = 0;
2298
2299         while (1) {
2300                 cond_resched();
2301
2302                 leaf = path->nodes[0];
2303                 slot = path->slots[0];
2304
2305                 if (slot >= btrfs_header_nritems(leaf)) {
2306                         ret = btrfs_next_leaf(root, path);
2307                         if (ret < 0) {
2308                                 goto out;
2309                         } else if (ret > 0) {
2310                                 ret = 0;
2311                                 goto out;
2312                         }
2313                         continue;
2314                 }
2315
2316                 path->slots[0]++;
2317
2318                 btrfs_item_key_to_cpu(leaf, &key, slot);
2319
2320                 if (key.objectid > inum)
2321                         goto out;
2322
2323                 if (key.objectid < inum || key.type != BTRFS_EXTENT_DATA_KEY)
2324                         continue;
2325
2326                 extent = btrfs_item_ptr(leaf, slot,
2327                                         struct btrfs_file_extent_item);
2328
2329                 if (btrfs_file_extent_disk_bytenr(leaf, extent) != old->bytenr)
2330                         continue;
2331
2332                 /*
2333                  * 'offset' refers to the exact key.offset,
2334                  * NOT the 'offset' field in btrfs_extent_data_ref, ie.
2335                  * (key.offset - extent_offset).
2336                  */
2337                 if (key.offset != offset)
2338                         continue;
2339
2340                 extent_offset = btrfs_file_extent_offset(leaf, extent);
2341                 num_bytes = btrfs_file_extent_num_bytes(leaf, extent);
2342
2343                 if (extent_offset >= old->extent_offset + old->offset +
2344                     old->len || extent_offset + num_bytes <=
2345                     old->extent_offset + old->offset)
2346                         continue;
2347                 break;
2348         }
2349
2350         backref = kmalloc(sizeof(*backref), GFP_NOFS);
2351         if (!backref) {
2352                 ret = -ENOENT;
2353                 goto out;
2354         }
2355
2356         backref->root_id = root_id;
2357         backref->inum = inum;
2358         backref->file_pos = offset;
2359         backref->num_bytes = num_bytes;
2360         backref->extent_offset = extent_offset;
2361         backref->generation = btrfs_file_extent_generation(leaf, extent);
2362         backref->old = old;
2363         backref_insert(&new->root, backref);
2364         old->count++;
2365 out:
2366         btrfs_release_path(path);
2367         WARN_ON(ret);
2368         return ret;
2369 }
2370
2371 static noinline bool record_extent_backrefs(struct btrfs_path *path,
2372                                    struct new_sa_defrag_extent *new)
2373 {
2374         struct btrfs_fs_info *fs_info = BTRFS_I(new->inode)->root->fs_info;
2375         struct old_sa_defrag_extent *old, *tmp;
2376         int ret;
2377
2378         new->path = path;
2379
2380         list_for_each_entry_safe(old, tmp, &new->head, list) {
2381                 ret = iterate_inodes_from_logical(old->bytenr +
2382                                                   old->extent_offset, fs_info,
2383                                                   path, record_one_backref,
2384                                                   old);
2385                 if (ret < 0 && ret != -ENOENT)
2386                         return false;
2387
2388                 /* no backref to be processed for this extent */
2389                 if (!old->count) {
2390                         list_del(&old->list);
2391                         kfree(old);
2392                 }
2393         }
2394
2395         if (list_empty(&new->head))
2396                 return false;
2397
2398         return true;
2399 }
2400
2401 static int relink_is_mergable(struct extent_buffer *leaf,
2402                               struct btrfs_file_extent_item *fi,
2403                               struct new_sa_defrag_extent *new)
2404 {
2405         if (btrfs_file_extent_disk_bytenr(leaf, fi) != new->bytenr)
2406                 return 0;
2407
2408         if (btrfs_file_extent_type(leaf, fi) != BTRFS_FILE_EXTENT_REG)
2409                 return 0;
2410
2411         if (btrfs_file_extent_compression(leaf, fi) != new->compress_type)
2412                 return 0;
2413
2414         if (btrfs_file_extent_encryption(leaf, fi) ||
2415             btrfs_file_extent_other_encoding(leaf, fi))
2416                 return 0;
2417
2418         return 1;
2419 }
2420
2421 /*
2422  * Note the backref might has changed, and in this case we just return 0.
2423  */
2424 static noinline int relink_extent_backref(struct btrfs_path *path,
2425                                  struct sa_defrag_extent_backref *prev,
2426                                  struct sa_defrag_extent_backref *backref)
2427 {
2428         struct btrfs_file_extent_item *extent;
2429         struct btrfs_file_extent_item *item;
2430         struct btrfs_ordered_extent *ordered;
2431         struct btrfs_trans_handle *trans;
2432         struct btrfs_fs_info *fs_info;
2433         struct btrfs_root *root;
2434         struct btrfs_key key;
2435         struct extent_buffer *leaf;
2436         struct old_sa_defrag_extent *old = backref->old;
2437         struct new_sa_defrag_extent *new = old->new;
2438         struct inode *src_inode = new->inode;
2439         struct inode *inode;
2440         struct extent_state *cached = NULL;
2441         int ret = 0;
2442         u64 start;
2443         u64 len;
2444         u64 lock_start;
2445         u64 lock_end;
2446         bool merge = false;
2447         int index;
2448
2449         if (prev && prev->root_id == backref->root_id &&
2450             prev->inum == backref->inum &&
2451             prev->file_pos + prev->num_bytes == backref->file_pos)
2452                 merge = true;
2453
2454         /* step 1: get root */
2455         key.objectid = backref->root_id;
2456         key.type = BTRFS_ROOT_ITEM_KEY;
2457         key.offset = (u64)-1;
2458
2459         fs_info = BTRFS_I(src_inode)->root->fs_info;
2460         index = srcu_read_lock(&fs_info->subvol_srcu);
2461
2462         root = btrfs_read_fs_root_no_name(fs_info, &key);
2463         if (IS_ERR(root)) {
2464                 srcu_read_unlock(&fs_info->subvol_srcu, index);
2465                 if (PTR_ERR(root) == -ENOENT)
2466                         return 0;
2467                 return PTR_ERR(root);
2468         }
2469
2470         if (btrfs_root_readonly(root)) {
2471                 srcu_read_unlock(&fs_info->subvol_srcu, index);
2472                 return 0;
2473         }
2474
2475         /* step 2: get inode */
2476         key.objectid = backref->inum;
2477         key.type = BTRFS_INODE_ITEM_KEY;
2478         key.offset = 0;
2479
2480         inode = btrfs_iget(fs_info->sb, &key, root, NULL);
2481         if (IS_ERR(inode)) {
2482                 srcu_read_unlock(&fs_info->subvol_srcu, index);
2483                 return 0;
2484         }
2485
2486         srcu_read_unlock(&fs_info->subvol_srcu, index);
2487
2488         /* step 3: relink backref */
2489         lock_start = backref->file_pos;
2490         lock_end = backref->file_pos + backref->num_bytes - 1;
2491         lock_extent_bits(&BTRFS_I(inode)->io_tree, lock_start, lock_end,
2492                          &cached);
2493
2494         ordered = btrfs_lookup_first_ordered_extent(inode, lock_end);
2495         if (ordered) {
2496                 btrfs_put_ordered_extent(ordered);
2497                 goto out_unlock;
2498         }
2499
2500         trans = btrfs_join_transaction(root);
2501         if (IS_ERR(trans)) {
2502                 ret = PTR_ERR(trans);
2503                 goto out_unlock;
2504         }
2505
2506         key.objectid = backref->inum;
2507         key.type = BTRFS_EXTENT_DATA_KEY;
2508         key.offset = backref->file_pos;
2509
2510         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
2511         if (ret < 0) {
2512                 goto out_free_path;
2513         } else if (ret > 0) {
2514                 ret = 0;
2515                 goto out_free_path;
2516         }
2517
2518         extent = btrfs_item_ptr(path->nodes[0], path->slots[0],
2519                                 struct btrfs_file_extent_item);
2520
2521         if (btrfs_file_extent_generation(path->nodes[0], extent) !=
2522             backref->generation)
2523                 goto out_free_path;
2524
2525         btrfs_release_path(path);
2526
2527         start = backref->file_pos;
2528         if (backref->extent_offset < old->extent_offset + old->offset)
2529                 start += old->extent_offset + old->offset -
2530                          backref->extent_offset;
2531
2532         len = min(backref->extent_offset + backref->num_bytes,
2533                   old->extent_offset + old->offset + old->len);
2534         len -= max(backref->extent_offset, old->extent_offset + old->offset);
2535
2536         ret = btrfs_drop_extents(trans, root, inode, start,
2537                                  start + len, 1);
2538         if (ret)
2539                 goto out_free_path;
2540 again:
2541         key.objectid = btrfs_ino(inode);
2542         key.type = BTRFS_EXTENT_DATA_KEY;
2543         key.offset = start;
2544
2545         path->leave_spinning = 1;
2546         if (merge) {
2547                 struct btrfs_file_extent_item *fi;
2548                 u64 extent_len;
2549                 struct btrfs_key found_key;
2550
2551                 ret = btrfs_search_slot(trans, root, &key, path, 0, 1);
2552                 if (ret < 0)
2553                         goto out_free_path;
2554
2555                 path->slots[0]--;
2556                 leaf = path->nodes[0];
2557                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
2558
2559                 fi = btrfs_item_ptr(leaf, path->slots[0],
2560                                     struct btrfs_file_extent_item);
2561                 extent_len = btrfs_file_extent_num_bytes(leaf, fi);
2562
2563                 if (extent_len + found_key.offset == start &&
2564                     relink_is_mergable(leaf, fi, new)) {
2565                         btrfs_set_file_extent_num_bytes(leaf, fi,
2566                                                         extent_len + len);
2567                         btrfs_mark_buffer_dirty(leaf);
2568                         inode_add_bytes(inode, len);
2569
2570                         ret = 1;
2571                         goto out_free_path;
2572                 } else {
2573                         merge = false;
2574                         btrfs_release_path(path);
2575                         goto again;
2576                 }
2577         }
2578
2579         ret = btrfs_insert_empty_item(trans, root, path, &key,
2580                                         sizeof(*extent));
2581         if (ret) {
2582                 btrfs_abort_transaction(trans, root, ret);
2583                 goto out_free_path;
2584         }
2585
2586         leaf = path->nodes[0];
2587         item = btrfs_item_ptr(leaf, path->slots[0],
2588                                 struct btrfs_file_extent_item);
2589         btrfs_set_file_extent_disk_bytenr(leaf, item, new->bytenr);
2590         btrfs_set_file_extent_disk_num_bytes(leaf, item, new->disk_len);
2591         btrfs_set_file_extent_offset(leaf, item, start - new->file_pos);
2592         btrfs_set_file_extent_num_bytes(leaf, item, len);
2593         btrfs_set_file_extent_ram_bytes(leaf, item, new->len);
2594         btrfs_set_file_extent_generation(leaf, item, trans->transid);
2595         btrfs_set_file_extent_type(leaf, item, BTRFS_FILE_EXTENT_REG);
2596         btrfs_set_file_extent_compression(leaf, item, new->compress_type);
2597         btrfs_set_file_extent_encryption(leaf, item, 0);
2598         btrfs_set_file_extent_other_encoding(leaf, item, 0);
2599
2600         btrfs_mark_buffer_dirty(leaf);
2601         inode_add_bytes(inode, len);
2602         btrfs_release_path(path);
2603
2604         ret = btrfs_inc_extent_ref(trans, root, new->bytenr,
2605                         new->disk_len, 0,
2606                         backref->root_id, backref->inum,
2607                         new->file_pos); /* start - extent_offset */
2608         if (ret) {
2609                 btrfs_abort_transaction(trans, root, ret);
2610                 goto out_free_path;
2611         }
2612
2613         ret = 1;
2614 out_free_path:
2615         btrfs_release_path(path);
2616         path->leave_spinning = 0;
2617         btrfs_end_transaction(trans, root);
2618 out_unlock:
2619         unlock_extent_cached(&BTRFS_I(inode)->io_tree, lock_start, lock_end,
2620                              &cached, GFP_NOFS);
2621         iput(inode);
2622         return ret;
2623 }
2624
2625 static void free_sa_defrag_extent(struct new_sa_defrag_extent *new)
2626 {
2627         struct old_sa_defrag_extent *old, *tmp;
2628
2629         if (!new)
2630                 return;
2631
2632         list_for_each_entry_safe(old, tmp, &new->head, list) {
2633                 kfree(old);
2634         }
2635         kfree(new);
2636 }
2637
2638 static void relink_file_extents(struct new_sa_defrag_extent *new)
2639 {
2640         struct btrfs_path *path;
2641         struct sa_defrag_extent_backref *backref;
2642         struct sa_defrag_extent_backref *prev = NULL;
2643         struct inode *inode;
2644         struct btrfs_root *root;
2645         struct rb_node *node;
2646         int ret;
2647
2648         inode = new->inode;
2649         root = BTRFS_I(inode)->root;
2650
2651         path = btrfs_alloc_path();
2652         if (!path)
2653                 return;
2654
2655         if (!record_extent_backrefs(path, new)) {
2656                 btrfs_free_path(path);
2657                 goto out;
2658         }
2659         btrfs_release_path(path);
2660
2661         while (1) {
2662                 node = rb_first(&new->root);
2663                 if (!node)
2664                         break;
2665                 rb_erase(node, &new->root);
2666
2667                 backref = rb_entry(node, struct sa_defrag_extent_backref, node);
2668
2669                 ret = relink_extent_backref(path, prev, backref);
2670                 WARN_ON(ret < 0);
2671
2672                 kfree(prev);
2673
2674                 if (ret == 1)
2675                         prev = backref;
2676                 else
2677                         prev = NULL;
2678                 cond_resched();
2679         }
2680         kfree(prev);
2681
2682         btrfs_free_path(path);
2683 out:
2684         free_sa_defrag_extent(new);
2685
2686         atomic_dec(&root->fs_info->defrag_running);
2687         wake_up(&root->fs_info->transaction_wait);
2688 }
2689
2690 static struct new_sa_defrag_extent *
2691 record_old_file_extents(struct inode *inode,
2692                         struct btrfs_ordered_extent *ordered)
2693 {
2694         struct btrfs_root *root = BTRFS_I(inode)->root;
2695         struct btrfs_path *path;
2696         struct btrfs_key key;
2697         struct old_sa_defrag_extent *old;
2698         struct new_sa_defrag_extent *new;
2699         int ret;
2700
2701         new = kmalloc(sizeof(*new), GFP_NOFS);
2702         if (!new)
2703                 return NULL;
2704
2705         new->inode = inode;
2706         new->file_pos = ordered->file_offset;
2707         new->len = ordered->len;
2708         new->bytenr = ordered->start;
2709         new->disk_len = ordered->disk_len;
2710         new->compress_type = ordered->compress_type;
2711         new->root = RB_ROOT;
2712         INIT_LIST_HEAD(&new->head);
2713
2714         path = btrfs_alloc_path();
2715         if (!path)
2716                 goto out_kfree;
2717
2718         key.objectid = btrfs_ino(inode);
2719         key.type = BTRFS_EXTENT_DATA_KEY;
2720         key.offset = new->file_pos;
2721
2722         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
2723         if (ret < 0)
2724                 goto out_free_path;
2725         if (ret > 0 && path->slots[0] > 0)
2726                 path->slots[0]--;
2727
2728         /* find out all the old extents for the file range */
2729         while (1) {
2730                 struct btrfs_file_extent_item *extent;
2731                 struct extent_buffer *l;
2732                 int slot;
2733                 u64 num_bytes;
2734                 u64 offset;
2735                 u64 end;
2736                 u64 disk_bytenr;
2737                 u64 extent_offset;
2738
2739                 l = path->nodes[0];
2740                 slot = path->slots[0];
2741
2742                 if (slot >= btrfs_header_nritems(l)) {
2743                         ret = btrfs_next_leaf(root, path);
2744                         if (ret < 0)
2745                                 goto out_free_path;
2746                         else if (ret > 0)
2747                                 break;
2748                         continue;
2749                 }
2750
2751                 btrfs_item_key_to_cpu(l, &key, slot);
2752
2753                 if (key.objectid != btrfs_ino(inode))
2754                         break;
2755                 if (key.type != BTRFS_EXTENT_DATA_KEY)
2756                         break;
2757                 if (key.offset >= new->file_pos + new->len)
2758                         break;
2759
2760                 extent = btrfs_item_ptr(l, slot, struct btrfs_file_extent_item);
2761
2762                 num_bytes = btrfs_file_extent_num_bytes(l, extent);
2763                 if (key.offset + num_bytes < new->file_pos)
2764                         goto next;
2765
2766                 disk_bytenr = btrfs_file_extent_disk_bytenr(l, extent);
2767                 if (!disk_bytenr)
2768                         goto next;
2769
2770                 extent_offset = btrfs_file_extent_offset(l, extent);
2771
2772                 old = kmalloc(sizeof(*old), GFP_NOFS);
2773                 if (!old)
2774                         goto out_free_path;
2775
2776                 offset = max(new->file_pos, key.offset);
2777                 end = min(new->file_pos + new->len, key.offset + num_bytes);
2778
2779                 old->bytenr = disk_bytenr;
2780                 old->extent_offset = extent_offset;
2781                 old->offset = offset - key.offset;
2782                 old->len = end - offset;
2783                 old->new = new;
2784                 old->count = 0;
2785                 list_add_tail(&old->list, &new->head);
2786 next:
2787                 path->slots[0]++;
2788                 cond_resched();
2789         }
2790
2791         btrfs_free_path(path);
2792         atomic_inc(&root->fs_info->defrag_running);
2793
2794         return new;
2795
2796 out_free_path:
2797         btrfs_free_path(path);
2798 out_kfree:
2799         free_sa_defrag_extent(new);
2800         return NULL;
2801 }
2802
2803 static void btrfs_release_delalloc_bytes(struct btrfs_root *root,
2804                                          u64 start, u64 len)
2805 {
2806         struct btrfs_block_group_cache *cache;
2807
2808         cache = btrfs_lookup_block_group(root->fs_info, start);
2809         ASSERT(cache);
2810
2811         spin_lock(&cache->lock);
2812         cache->delalloc_bytes -= len;
2813         spin_unlock(&cache->lock);
2814
2815         btrfs_put_block_group(cache);
2816 }
2817
2818 /* as ordered data IO finishes, this gets called so we can finish
2819  * an ordered extent if the range of bytes in the file it covers are
2820  * fully written.
2821  */
2822 static int btrfs_finish_ordered_io(struct btrfs_ordered_extent *ordered_extent)
2823 {
2824         struct inode *inode = ordered_extent->inode;
2825         struct btrfs_root *root = BTRFS_I(inode)->root;
2826         struct btrfs_trans_handle *trans = NULL;
2827         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
2828         struct extent_state *cached_state = NULL;
2829         struct new_sa_defrag_extent *new = NULL;
2830         int compress_type = 0;
2831         int ret = 0;
2832         u64 logical_len = ordered_extent->len;
2833         bool nolock;
2834         bool truncated = false;
2835
2836         nolock = btrfs_is_free_space_inode(inode);
2837
2838         if (test_bit(BTRFS_ORDERED_IOERR, &ordered_extent->flags)) {
2839                 ret = -EIO;
2840                 goto out;
2841         }
2842
2843         btrfs_free_io_failure_record(inode, ordered_extent->file_offset,
2844                                      ordered_extent->file_offset +
2845                                      ordered_extent->len - 1);
2846
2847         if (test_bit(BTRFS_ORDERED_TRUNCATED, &ordered_extent->flags)) {
2848                 truncated = true;
2849                 logical_len = ordered_extent->truncated_len;
2850                 /* Truncated the entire extent, don't bother adding */
2851                 if (!logical_len)
2852                         goto out;
2853         }
2854
2855         if (test_bit(BTRFS_ORDERED_NOCOW, &ordered_extent->flags)) {
2856                 BUG_ON(!list_empty(&ordered_extent->list)); /* Logic error */
2857
2858                 /*
2859                  * For mwrite(mmap + memset to write) case, we still reserve
2860                  * space for NOCOW range.
2861                  * As NOCOW won't cause a new delayed ref, just free the space
2862                  */
2863                 btrfs_qgroup_free_data(inode, ordered_extent->file_offset,
2864                                        ordered_extent->len);
2865                 btrfs_ordered_update_i_size(inode, 0, ordered_extent);
2866                 if (nolock)
2867                         trans = btrfs_join_transaction_nolock(root);
2868                 else
2869                         trans = btrfs_join_transaction(root);
2870                 if (IS_ERR(trans)) {
2871                         ret = PTR_ERR(trans);
2872                         trans = NULL;
2873                         goto out;
2874                 }
2875                 trans->block_rsv = &root->fs_info->delalloc_block_rsv;
2876                 ret = btrfs_update_inode_fallback(trans, root, inode);
2877                 if (ret) /* -ENOMEM or corruption */
2878                         btrfs_abort_transaction(trans, root, ret);
2879                 goto out;
2880         }
2881
2882         lock_extent_bits(io_tree, ordered_extent->file_offset,
2883                          ordered_extent->file_offset + ordered_extent->len - 1,
2884                          &cached_state);
2885
2886         ret = test_range_bit(io_tree, ordered_extent->file_offset,
2887                         ordered_extent->file_offset + ordered_extent->len - 1,
2888                         EXTENT_DEFRAG, 1, cached_state);
2889         if (ret) {
2890                 u64 last_snapshot = btrfs_root_last_snapshot(&root->root_item);
2891                 if (0 && last_snapshot >= BTRFS_I(inode)->generation)
2892                         /* the inode is shared */
2893                         new = record_old_file_extents(inode, ordered_extent);
2894
2895                 clear_extent_bit(io_tree, ordered_extent->file_offset,
2896                         ordered_extent->file_offset + ordered_extent->len - 1,
2897                         EXTENT_DEFRAG, 0, 0, &cached_state, GFP_NOFS);
2898         }
2899
2900         if (nolock)
2901                 trans = btrfs_join_transaction_nolock(root);
2902         else
2903                 trans = btrfs_join_transaction(root);
2904         if (IS_ERR(trans)) {
2905                 ret = PTR_ERR(trans);
2906                 trans = NULL;
2907                 goto out_unlock;
2908         }
2909
2910         trans->block_rsv = &root->fs_info->delalloc_block_rsv;
2911
2912         if (test_bit(BTRFS_ORDERED_COMPRESSED, &ordered_extent->flags))
2913                 compress_type = ordered_extent->compress_type;
2914         if (test_bit(BTRFS_ORDERED_PREALLOC, &ordered_extent->flags)) {
2915                 BUG_ON(compress_type);
2916                 ret = btrfs_mark_extent_written(trans, inode,
2917                                                 ordered_extent->file_offset,
2918                                                 ordered_extent->file_offset +
2919                                                 logical_len);
2920         } else {
2921                 BUG_ON(root == root->fs_info->tree_root);
2922                 ret = insert_reserved_file_extent(trans, inode,
2923                                                 ordered_extent->file_offset,
2924                                                 ordered_extent->start,
2925                                                 ordered_extent->disk_len,
2926                                                 logical_len, logical_len,
2927                                                 compress_type, 0, 0,
2928                                                 BTRFS_FILE_EXTENT_REG);
2929                 if (!ret)
2930                         btrfs_release_delalloc_bytes(root,
2931                                                      ordered_extent->start,
2932                                                      ordered_extent->disk_len);
2933         }
2934         unpin_extent_cache(&BTRFS_I(inode)->extent_tree,
2935                            ordered_extent->file_offset, ordered_extent->len,
2936                            trans->transid);
2937         if (ret < 0) {
2938                 btrfs_abort_transaction(trans, root, ret);
2939                 goto out_unlock;
2940         }
2941
2942         add_pending_csums(trans, inode, ordered_extent->file_offset,
2943                           &ordered_extent->list);
2944
2945         btrfs_ordered_update_i_size(inode, 0, ordered_extent);
2946         ret = btrfs_update_inode_fallback(trans, root, inode);
2947         if (ret) { /* -ENOMEM or corruption */
2948                 btrfs_abort_transaction(trans, root, ret);
2949                 goto out_unlock;
2950         }
2951         ret = 0;
2952 out_unlock:
2953         unlock_extent_cached(io_tree, ordered_extent->file_offset,
2954                              ordered_extent->file_offset +
2955                              ordered_extent->len - 1, &cached_state, GFP_NOFS);
2956 out:
2957         if (root != root->fs_info->tree_root)
2958                 btrfs_delalloc_release_metadata(inode, ordered_extent->len);
2959         if (trans)
2960                 btrfs_end_transaction(trans, root);
2961
2962         if (ret || truncated) {
2963                 u64 start, end;
2964
2965                 if (truncated)
2966                         start = ordered_extent->file_offset + logical_len;
2967                 else
2968                         start = ordered_extent->file_offset;
2969                 end = ordered_extent->file_offset + ordered_extent->len - 1;
2970                 clear_extent_uptodate(io_tree, start, end, NULL, GFP_NOFS);
2971
2972                 /* Drop the cache for the part of the extent we didn't write. */
2973                 btrfs_drop_extent_cache(inode, start, end, 0);
2974
2975                 /*
2976                  * If the ordered extent had an IOERR or something else went
2977                  * wrong we need to return the space for this ordered extent
2978                  * back to the allocator.  We only free the extent in the
2979                  * truncated case if we didn't write out the extent at all.
2980                  */
2981                 if ((ret || !logical_len) &&
2982                     !test_bit(BTRFS_ORDERED_NOCOW, &ordered_extent->flags) &&
2983                     !test_bit(BTRFS_ORDERED_PREALLOC, &ordered_extent->flags))
2984                         btrfs_free_reserved_extent(root, ordered_extent->start,
2985                                                    ordered_extent->disk_len, 1);
2986         }
2987
2988
2989         /*
2990          * This needs to be done to make sure anybody waiting knows we are done
2991          * updating everything for this ordered extent.
2992          */
2993         btrfs_remove_ordered_extent(inode, ordered_extent);
2994
2995         /* for snapshot-aware defrag */
2996         if (new) {
2997                 if (ret) {
2998                         free_sa_defrag_extent(new);
2999                         atomic_dec(&root->fs_info->defrag_running);
3000                 } else {
3001                         relink_file_extents(new);
3002                 }
3003         }
3004
3005         /* once for us */
3006         btrfs_put_ordered_extent(ordered_extent);
3007         /* once for the tree */
3008         btrfs_put_ordered_extent(ordered_extent);
3009
3010         return ret;
3011 }
3012
3013 static void finish_ordered_fn(struct btrfs_work *work)
3014 {
3015         struct btrfs_ordered_extent *ordered_extent;
3016         ordered_extent = container_of(work, struct btrfs_ordered_extent, work);
3017         btrfs_finish_ordered_io(ordered_extent);
3018 }
3019
3020 static int btrfs_writepage_end_io_hook(struct page *page, u64 start, u64 end,
3021                                 struct extent_state *state, int uptodate)
3022 {
3023         struct inode *inode = page->mapping->host;
3024         struct btrfs_root *root = BTRFS_I(inode)->root;
3025         struct btrfs_ordered_extent *ordered_extent = NULL;
3026         struct btrfs_workqueue *wq;
3027         btrfs_work_func_t func;
3028
3029         trace_btrfs_writepage_end_io_hook(page, start, end, uptodate);
3030
3031         ClearPagePrivate2(page);
3032         if (!btrfs_dec_test_ordered_pending(inode, &ordered_extent, start,
3033                                             end - start + 1, uptodate))
3034                 return 0;
3035
3036         if (btrfs_is_free_space_inode(inode)) {
3037                 wq = root->fs_info->endio_freespace_worker;
3038                 func = btrfs_freespace_write_helper;
3039         } else {
3040                 wq = root->fs_info->endio_write_workers;
3041                 func = btrfs_endio_write_helper;
3042         }
3043
3044         btrfs_init_work(&ordered_extent->work, func, finish_ordered_fn, NULL,
3045                         NULL);
3046         btrfs_queue_work(wq, &ordered_extent->work);
3047
3048         return 0;
3049 }
3050
3051 static int __readpage_endio_check(struct inode *inode,
3052                                   struct btrfs_io_bio *io_bio,
3053                                   int icsum, struct page *page,
3054                                   int pgoff, u64 start, size_t len)
3055 {
3056         char *kaddr;
3057         u32 csum_expected;
3058         u32 csum = ~(u32)0;
3059
3060         csum_expected = *(((u32 *)io_bio->csum) + icsum);
3061
3062         kaddr = kmap_atomic(page);
3063         csum = btrfs_csum_data(kaddr + pgoff, csum,  len);
3064         btrfs_csum_final(csum, (char *)&csum);
3065         if (csum != csum_expected)
3066                 goto zeroit;
3067
3068         kunmap_atomic(kaddr);
3069         return 0;
3070 zeroit:
3071         btrfs_warn_rl(BTRFS_I(inode)->root->fs_info,
3072                 "csum failed ino %llu off %llu csum %u expected csum %u",
3073                            btrfs_ino(inode), start, csum, csum_expected);
3074         memset(kaddr + pgoff, 1, len);
3075         flush_dcache_page(page);
3076         kunmap_atomic(kaddr);
3077         if (csum_expected == 0)
3078                 return 0;
3079         return -EIO;
3080 }
3081
3082 /*
3083  * when reads are done, we need to check csums to verify the data is correct
3084  * if there's a match, we allow the bio to finish.  If not, the code in
3085  * extent_io.c will try to find good copies for us.
3086  */
3087 static int btrfs_readpage_end_io_hook(struct btrfs_io_bio *io_bio,
3088                                       u64 phy_offset, struct page *page,
3089                                       u64 start, u64 end, int mirror)
3090 {
3091         size_t offset = start - page_offset(page);
3092         struct inode *inode = page->mapping->host;
3093         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
3094         struct btrfs_root *root = BTRFS_I(inode)->root;
3095
3096         if (PageChecked(page)) {
3097                 ClearPageChecked(page);
3098                 return 0;
3099         }
3100
3101         if (BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM)
3102                 return 0;
3103
3104         if (root->root_key.objectid == BTRFS_DATA_RELOC_TREE_OBJECTID &&
3105             test_range_bit(io_tree, start, end, EXTENT_NODATASUM, 1, NULL)) {
3106                 clear_extent_bits(io_tree, start, end, EXTENT_NODATASUM,
3107                                   GFP_NOFS);
3108                 return 0;
3109         }
3110
3111         phy_offset >>= inode->i_sb->s_blocksize_bits;
3112         return __readpage_endio_check(inode, io_bio, phy_offset, page, offset,
3113                                       start, (size_t)(end - start + 1));
3114 }
3115
3116 void btrfs_add_delayed_iput(struct inode *inode)
3117 {
3118         struct btrfs_fs_info *fs_info = BTRFS_I(inode)->root->fs_info;
3119         struct btrfs_inode *binode = BTRFS_I(inode);
3120
3121         if (atomic_add_unless(&inode->i_count, -1, 1))
3122                 return;
3123
3124         spin_lock(&fs_info->delayed_iput_lock);
3125         if (binode->delayed_iput_count == 0) {
3126                 ASSERT(list_empty(&binode->delayed_iput));
3127                 list_add_tail(&binode->delayed_iput, &fs_info->delayed_iputs);
3128         } else {
3129                 binode->delayed_iput_count++;
3130         }
3131         spin_unlock(&fs_info->delayed_iput_lock);
3132 }
3133
3134 void btrfs_run_delayed_iputs(struct btrfs_root *root)
3135 {
3136         struct btrfs_fs_info *fs_info = root->fs_info;
3137
3138         spin_lock(&fs_info->delayed_iput_lock);
3139         while (!list_empty(&fs_info->delayed_iputs)) {
3140                 struct btrfs_inode *inode;
3141
3142                 inode = list_first_entry(&fs_info->delayed_iputs,
3143                                 struct btrfs_inode, delayed_iput);
3144                 if (inode->delayed_iput_count) {
3145                         inode->delayed_iput_count--;
3146                         list_move_tail(&inode->delayed_iput,
3147                                         &fs_info->delayed_iputs);
3148                 } else {
3149                         list_del_init(&inode->delayed_iput);
3150                 }
3151                 spin_unlock(&fs_info->delayed_iput_lock);
3152                 iput(&inode->vfs_inode);
3153                 spin_lock(&fs_info->delayed_iput_lock);
3154         }
3155         spin_unlock(&fs_info->delayed_iput_lock);
3156 }
3157
3158 /*
3159  * This is called in transaction commit time. If there are no orphan
3160  * files in the subvolume, it removes orphan item and frees block_rsv
3161  * structure.
3162  */
3163 void btrfs_orphan_commit_root(struct btrfs_trans_handle *trans,
3164                               struct btrfs_root *root)
3165 {
3166         struct btrfs_block_rsv *block_rsv;
3167         int ret;
3168
3169         if (atomic_read(&root->orphan_inodes) ||
3170             root->orphan_cleanup_state != ORPHAN_CLEANUP_DONE)
3171                 return;
3172
3173         spin_lock(&root->orphan_lock);
3174         if (atomic_read(&root->orphan_inodes)) {
3175                 spin_unlock(&root->orphan_lock);
3176                 return;
3177         }
3178
3179         if (root->orphan_cleanup_state != ORPHAN_CLEANUP_DONE) {
3180                 spin_unlock(&root->orphan_lock);
3181                 return;
3182         }
3183
3184         block_rsv = root->orphan_block_rsv;
3185         root->orphan_block_rsv = NULL;
3186         spin_unlock(&root->orphan_lock);
3187
3188         if (test_bit(BTRFS_ROOT_ORPHAN_ITEM_INSERTED, &root->state) &&
3189             btrfs_root_refs(&root->root_item) > 0) {
3190                 ret = btrfs_del_orphan_item(trans, root->fs_info->tree_root,
3191                                             root->root_key.objectid);
3192                 if (ret)
3193                         btrfs_abort_transaction(trans, root, ret);
3194                 else
3195                         clear_bit(BTRFS_ROOT_ORPHAN_ITEM_INSERTED,
3196                                   &root->state);
3197         }
3198
3199         if (block_rsv) {
3200                 WARN_ON(block_rsv->size > 0);
3201                 btrfs_free_block_rsv(root, block_rsv);
3202         }
3203 }
3204
3205 /*
3206  * This creates an orphan entry for the given inode in case something goes
3207  * wrong in the middle of an unlink/truncate.
3208  *
3209  * NOTE: caller of this function should reserve 5 units of metadata for
3210  *       this function.
3211  */
3212 int btrfs_orphan_add(struct btrfs_trans_handle *trans, struct inode *inode)
3213 {
3214         struct btrfs_root *root = BTRFS_I(inode)->root;
3215         struct btrfs_block_rsv *block_rsv = NULL;
3216         int reserve = 0;
3217         int insert = 0;
3218         int ret;
3219
3220         if (!root->orphan_block_rsv) {
3221                 block_rsv = btrfs_alloc_block_rsv(root, BTRFS_BLOCK_RSV_TEMP);
3222                 if (!block_rsv)
3223                         return -ENOMEM;
3224         }
3225
3226         spin_lock(&root->orphan_lock);
3227         if (!root->orphan_block_rsv) {
3228                 root->orphan_block_rsv = block_rsv;
3229         } else if (block_rsv) {
3230                 btrfs_free_block_rsv(root, block_rsv);
3231                 block_rsv = NULL;
3232         }
3233
3234         if (!test_and_set_bit(BTRFS_INODE_HAS_ORPHAN_ITEM,
3235                               &BTRFS_I(inode)->runtime_flags)) {
3236 #if 0
3237                 /*
3238                  * For proper ENOSPC handling, we should do orphan
3239                  * cleanup when mounting. But this introduces backward
3240                  * compatibility issue.
3241                  */
3242                 if (!xchg(&root->orphan_item_inserted, 1))
3243                         insert = 2;
3244                 else
3245                         insert = 1;
3246 #endif
3247                 insert = 1;
3248                 atomic_inc(&root->orphan_inodes);
3249         }
3250
3251         if (!test_and_set_bit(BTRFS_INODE_ORPHAN_META_RESERVED,
3252                               &BTRFS_I(inode)->runtime_flags))
3253                 reserve = 1;
3254         spin_unlock(&root->orphan_lock);
3255
3256         /* grab metadata reservation from transaction handle */
3257         if (reserve) {
3258                 ret = btrfs_orphan_reserve_metadata(trans, inode);
3259                 BUG_ON(ret); /* -ENOSPC in reservation; Logic error? JDM */
3260         }
3261
3262         /* insert an orphan item to track this unlinked/truncated file */
3263         if (insert >= 1) {
3264                 ret = btrfs_insert_orphan_item(trans, root, btrfs_ino(inode));
3265                 if (ret) {
3266                         atomic_dec(&root->orphan_inodes);
3267                         if (reserve) {
3268                                 clear_bit(BTRFS_INODE_ORPHAN_META_RESERVED,
3269                                           &BTRFS_I(inode)->runtime_flags);
3270                                 btrfs_orphan_release_metadata(inode);
3271                         }
3272                         if (ret != -EEXIST) {
3273                                 clear_bit(BTRFS_INODE_HAS_ORPHAN_ITEM,
3274                                           &BTRFS_I(inode)->runtime_flags);
3275                                 btrfs_abort_transaction(trans, root, ret);
3276                                 return ret;
3277                         }
3278                 }
3279                 ret = 0;
3280         }
3281
3282         /* insert an orphan item to track subvolume contains orphan files */
3283         if (insert >= 2) {
3284                 ret = btrfs_insert_orphan_item(trans, root->fs_info->tree_root,
3285                                                root->root_key.objectid);
3286                 if (ret && ret != -EEXIST) {
3287                         btrfs_abort_transaction(trans, root, ret);
3288                         return ret;
3289                 }
3290         }
3291         return 0;
3292 }
3293
3294 /*
3295  * We have done the truncate/delete so we can go ahead and remove the orphan
3296  * item for this particular inode.
3297  */
3298 static int btrfs_orphan_del(struct btrfs_trans_handle *trans,
3299                             struct inode *inode)
3300 {
3301         struct btrfs_root *root = BTRFS_I(inode)->root;
3302         int delete_item = 0;
3303         int release_rsv = 0;
3304         int ret = 0;
3305
3306         spin_lock(&root->orphan_lock);
3307         if (test_and_clear_bit(BTRFS_INODE_HAS_ORPHAN_ITEM,
3308                                &BTRFS_I(inode)->runtime_flags))
3309                 delete_item = 1;
3310
3311         if (test_and_clear_bit(BTRFS_INODE_ORPHAN_META_RESERVED,
3312                                &BTRFS_I(inode)->runtime_flags))
3313                 release_rsv = 1;
3314         spin_unlock(&root->orphan_lock);
3315
3316         if (delete_item) {
3317                 atomic_dec(&root->orphan_inodes);
3318                 if (trans)
3319                         ret = btrfs_del_orphan_item(trans, root,
3320                                                     btrfs_ino(inode));
3321         }
3322
3323         if (release_rsv)
3324                 btrfs_orphan_release_metadata(inode);
3325
3326         return ret;
3327 }
3328
3329 /*
3330  * this cleans up any orphans that may be left on the list from the last use
3331  * of this root.
3332  */
3333 int btrfs_orphan_cleanup(struct btrfs_root *root)
3334 {
3335         struct btrfs_path *path;
3336         struct extent_buffer *leaf;
3337         struct btrfs_key key, found_key;
3338         struct btrfs_trans_handle *trans;
3339         struct inode *inode;
3340         u64 last_objectid = 0;
3341         int ret = 0, nr_unlink = 0, nr_truncate = 0;
3342
3343         if (cmpxchg(&root->orphan_cleanup_state, 0, ORPHAN_CLEANUP_STARTED))
3344                 return 0;
3345
3346         path = btrfs_alloc_path();
3347         if (!path) {
3348                 ret = -ENOMEM;
3349                 goto out;
3350         }
3351         path->reada = READA_BACK;
3352
3353         key.objectid = BTRFS_ORPHAN_OBJECTID;
3354         key.type = BTRFS_ORPHAN_ITEM_KEY;
3355         key.offset = (u64)-1;
3356
3357         while (1) {
3358                 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
3359                 if (ret < 0)
3360                         goto out;
3361
3362                 /*
3363                  * if ret == 0 means we found what we were searching for, which
3364                  * is weird, but possible, so only screw with path if we didn't
3365                  * find the key and see if we have stuff that matches
3366                  */
3367                 if (ret > 0) {
3368                         ret = 0;
3369                         if (path->slots[0] == 0)
3370                                 break;
3371                         path->slots[0]--;
3372                 }
3373
3374                 /* pull out the item */
3375                 leaf = path->nodes[0];
3376                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
3377
3378                 /* make sure the item matches what we want */
3379                 if (found_key.objectid != BTRFS_ORPHAN_OBJECTID)
3380                         break;
3381                 if (found_key.type != BTRFS_ORPHAN_ITEM_KEY)
3382                         break;
3383
3384                 /* release the path since we're done with it */
3385                 btrfs_release_path(path);
3386
3387                 /*
3388                  * this is where we are basically btrfs_lookup, without the
3389                  * crossing root thing.  we store the inode number in the
3390                  * offset of the orphan item.
3391                  */
3392
3393                 if (found_key.offset == last_objectid) {
3394                         btrfs_err(root->fs_info,
3395                                 "Error removing orphan entry, stopping orphan cleanup");
3396                         ret = -EINVAL;
3397                         goto out;
3398                 }
3399
3400                 last_objectid = found_key.offset;
3401
3402                 found_key.objectid = found_key.offset;
3403                 found_key.type = BTRFS_INODE_ITEM_KEY;
3404                 found_key.offset = 0;
3405                 inode = btrfs_iget(root->fs_info->sb, &found_key, root, NULL);
3406                 ret = PTR_ERR_OR_ZERO(inode);
3407                 if (ret && ret != -ESTALE)
3408                         goto out;
3409
3410                 if (ret == -ESTALE && root == root->fs_info->tree_root) {
3411                         struct btrfs_root *dead_root;
3412                         struct btrfs_fs_info *fs_info = root->fs_info;
3413                         int is_dead_root = 0;
3414
3415                         /*
3416                          * this is an orphan in the tree root. Currently these
3417                          * could come from 2 sources:
3418                          *  a) a snapshot deletion in progress
3419                          *  b) a free space cache inode
3420                          * We need to distinguish those two, as the snapshot
3421                          * orphan must not get deleted.
3422                          * find_dead_roots already ran before us, so if this
3423                          * is a snapshot deletion, we should find the root
3424                          * in the dead_roots list
3425                          */
3426                         spin_lock(&fs_info->trans_lock);
3427                         list_for_each_entry(dead_root, &fs_info->dead_roots,
3428                                             root_list) {
3429                                 if (dead_root->root_key.objectid ==
3430                                     found_key.objectid) {
3431                                         is_dead_root = 1;
3432                                         break;
3433                                 }
3434                         }
3435                         spin_unlock(&fs_info->trans_lock);
3436                         if (is_dead_root) {
3437                                 /* prevent this orphan from being found again */
3438                                 key.offset = found_key.objectid - 1;
3439                                 continue;
3440                         }
3441                 }
3442                 /*
3443                  * Inode is already gone but the orphan item is still there,
3444                  * kill the orphan item.
3445                  */
3446                 if (ret == -ESTALE) {
3447                         trans = btrfs_start_transaction(root, 1);
3448                         if (IS_ERR(trans)) {
3449                                 ret = PTR_ERR(trans);
3450                                 goto out;
3451                         }
3452                         btrfs_debug(root->fs_info, "auto deleting %Lu",
3453                                 found_key.objectid);
3454                         ret = btrfs_del_orphan_item(trans, root,
3455                                                     found_key.objectid);
3456                         btrfs_end_transaction(trans, root);
3457                         if (ret)
3458                                 goto out;
3459                         continue;
3460                 }
3461
3462                 /*
3463                  * add this inode to the orphan list so btrfs_orphan_del does
3464                  * the proper thing when we hit it
3465                  */
3466                 set_bit(BTRFS_INODE_HAS_ORPHAN_ITEM,
3467                         &BTRFS_I(inode)->runtime_flags);
3468                 atomic_inc(&root->orphan_inodes);
3469
3470                 /* if we have links, this was a truncate, lets do that */
3471                 if (inode->i_nlink) {
3472                         if (WARN_ON(!S_ISREG(inode->i_mode))) {
3473                                 iput(inode);
3474                                 continue;
3475                         }
3476                         nr_truncate++;
3477
3478                         /* 1 for the orphan item deletion. */
3479                         trans = btrfs_start_transaction(root, 1);
3480                         if (IS_ERR(trans)) {
3481                                 iput(inode);
3482                                 ret = PTR_ERR(trans);
3483                                 goto out;
3484                         }
3485                         ret = btrfs_orphan_add(trans, inode);
3486                         btrfs_end_transaction(trans, root);
3487                         if (ret) {
3488                                 iput(inode);
3489                                 goto out;
3490                         }
3491
3492                         ret = btrfs_truncate(inode);
3493                         if (ret)
3494                                 btrfs_orphan_del(NULL, inode);
3495                 } else {
3496                         nr_unlink++;
3497                 }
3498
3499                 /* this will do delete_inode and everything for us */
3500                 iput(inode);
3501                 if (ret)
3502                         goto out;
3503         }
3504         /* release the path since we're done with it */
3505         btrfs_release_path(path);
3506
3507         root->orphan_cleanup_state = ORPHAN_CLEANUP_DONE;
3508
3509         if (root->orphan_block_rsv)
3510                 btrfs_block_rsv_release(root, root->orphan_block_rsv,
3511                                         (u64)-1);
3512
3513         if (root->orphan_block_rsv ||
3514             test_bit(BTRFS_ROOT_ORPHAN_ITEM_INSERTED, &root->state)) {
3515                 trans = btrfs_join_transaction(root);
3516                 if (!IS_ERR(trans))
3517                         btrfs_end_transaction(trans, root);
3518         }
3519
3520         if (nr_unlink)
3521                 btrfs_debug(root->fs_info, "unlinked %d orphans", nr_unlink);
3522         if (nr_truncate)
3523                 btrfs_debug(root->fs_info, "truncated %d orphans", nr_truncate);
3524
3525 out:
3526         if (ret)
3527                 btrfs_err(root->fs_info,
3528                         "could not do orphan cleanup %d", ret);
3529         btrfs_free_path(path);
3530         return ret;
3531 }
3532
3533 /*
3534  * very simple check to peek ahead in the leaf looking for xattrs.  If we
3535  * don't find any xattrs, we know there can't be any acls.
3536  *
3537  * slot is the slot the inode is in, objectid is the objectid of the inode
3538  */
3539 static noinline int acls_after_inode_item(struct extent_buffer *leaf,
3540                                           int slot, u64 objectid,
3541                                           int *first_xattr_slot)
3542 {
3543         u32 nritems = btrfs_header_nritems(leaf);
3544         struct btrfs_key found_key;
3545         static u64 xattr_access = 0;
3546         static u64 xattr_default = 0;
3547         int scanned = 0;
3548
3549         if (!xattr_access) {
3550                 xattr_access = btrfs_name_hash(XATTR_NAME_POSIX_ACL_ACCESS,
3551                                         strlen(XATTR_NAME_POSIX_ACL_ACCESS));
3552                 xattr_default = btrfs_name_hash(XATTR_NAME_POSIX_ACL_DEFAULT,
3553                                         strlen(XATTR_NAME_POSIX_ACL_DEFAULT));
3554         }
3555
3556         slot++;
3557         *first_xattr_slot = -1;
3558         while (slot < nritems) {
3559                 btrfs_item_key_to_cpu(leaf, &found_key, slot);
3560
3561                 /* we found a different objectid, there must not be acls */
3562                 if (found_key.objectid != objectid)
3563                         return 0;
3564
3565                 /* we found an xattr, assume we've got an acl */
3566                 if (found_key.type == BTRFS_XATTR_ITEM_KEY) {
3567                         if (*first_xattr_slot == -1)
3568                                 *first_xattr_slot = slot;
3569                         if (found_key.offset == xattr_access ||
3570                             found_key.offset == xattr_default)
3571                                 return 1;
3572                 }
3573
3574                 /*
3575                  * we found a key greater than an xattr key, there can't
3576                  * be any acls later on
3577                  */
3578                 if (found_key.type > BTRFS_XATTR_ITEM_KEY)
3579                         return 0;
3580
3581                 slot++;
3582                 scanned++;
3583
3584                 /*
3585                  * it goes inode, inode backrefs, xattrs, extents,
3586                  * so if there are a ton of hard links to an inode there can
3587                  * be a lot of backrefs.  Don't waste time searching too hard,
3588                  * this is just an optimization
3589                  */
3590                 if (scanned >= 8)
3591                         break;
3592         }
3593         /* we hit the end of the leaf before we found an xattr or
3594          * something larger than an xattr.  We have to assume the inode
3595          * has acls
3596          */
3597         if (*first_xattr_slot == -1)
3598                 *first_xattr_slot = slot;
3599         return 1;
3600 }
3601
3602 /*
3603  * read an inode from the btree into the in-memory inode
3604  */
3605 static void btrfs_read_locked_inode(struct inode *inode)
3606 {
3607         struct btrfs_path *path;
3608         struct extent_buffer *leaf;
3609         struct btrfs_inode_item *inode_item;
3610         struct btrfs_root *root = BTRFS_I(inode)->root;
3611         struct btrfs_key location;
3612         unsigned long ptr;
3613         int maybe_acls;
3614         u32 rdev;
3615         int ret;
3616         bool filled = false;
3617         int first_xattr_slot;
3618
3619         ret = btrfs_fill_inode(inode, &rdev);
3620         if (!ret)
3621                 filled = true;
3622
3623         path = btrfs_alloc_path();
3624         if (!path)
3625                 goto make_bad;
3626
3627         memcpy(&location, &BTRFS_I(inode)->location, sizeof(location));
3628
3629         ret = btrfs_lookup_inode(NULL, root, path, &location, 0);
3630         if (ret)
3631                 goto make_bad;
3632
3633         leaf = path->nodes[0];
3634
3635         if (filled)
3636                 goto cache_index;
3637
3638         inode_item = btrfs_item_ptr(leaf, path->slots[0],
3639                                     struct btrfs_inode_item);
3640         inode->i_mode = btrfs_inode_mode(leaf, inode_item);
3641         set_nlink(inode, btrfs_inode_nlink(leaf, inode_item));
3642         i_uid_write(inode, btrfs_inode_uid(leaf, inode_item));
3643         i_gid_write(inode, btrfs_inode_gid(leaf, inode_item));
3644         btrfs_i_size_write(inode, btrfs_inode_size(leaf, inode_item));
3645
3646         inode->i_atime.tv_sec = btrfs_timespec_sec(leaf, &inode_item->atime);
3647         inode->i_atime.tv_nsec = btrfs_timespec_nsec(leaf, &inode_item->atime);
3648
3649         inode->i_mtime.tv_sec = btrfs_timespec_sec(leaf, &inode_item->mtime);
3650         inode->i_mtime.tv_nsec = btrfs_timespec_nsec(leaf, &inode_item->mtime);
3651
3652         inode->i_ctime.tv_sec = btrfs_timespec_sec(leaf, &inode_item->ctime);
3653         inode->i_ctime.tv_nsec = btrfs_timespec_nsec(leaf, &inode_item->ctime);
3654
3655         BTRFS_I(inode)->i_otime.tv_sec =
3656                 btrfs_timespec_sec(leaf, &inode_item->otime);
3657         BTRFS_I(inode)->i_otime.tv_nsec =
3658                 btrfs_timespec_nsec(leaf, &inode_item->otime);
3659
3660         inode_set_bytes(inode, btrfs_inode_nbytes(leaf, inode_item));
3661         BTRFS_I(inode)->generation = btrfs_inode_generation(leaf, inode_item);
3662         BTRFS_I(inode)->last_trans = btrfs_inode_transid(leaf, inode_item);
3663
3664         inode->i_version = btrfs_inode_sequence(leaf, inode_item);
3665         inode->i_generation = BTRFS_I(inode)->generation;
3666         inode->i_rdev = 0;
3667         rdev = btrfs_inode_rdev(leaf, inode_item);
3668
3669         BTRFS_I(inode)->index_cnt = (u64)-1;
3670         BTRFS_I(inode)->flags = btrfs_inode_flags(leaf, inode_item);
3671
3672 cache_index:
3673         /*
3674          * If we were modified in the current generation and evicted from memory
3675          * and then re-read we need to do a full sync since we don't have any
3676          * idea about which extents were modified before we were evicted from
3677          * cache.
3678          *
3679          * This is required for both inode re-read from disk and delayed inode
3680          * in delayed_nodes_tree.
3681          */
3682         if (BTRFS_I(inode)->last_trans == root->fs_info->generation)
3683                 set_bit(BTRFS_INODE_NEEDS_FULL_SYNC,
3684                         &BTRFS_I(inode)->runtime_flags);
3685
3686         /*
3687          * We don't persist the id of the transaction where an unlink operation
3688          * against the inode was last made. So here we assume the inode might
3689          * have been evicted, and therefore the exact value of last_unlink_trans
3690          * lost, and set it to last_trans to avoid metadata inconsistencies
3691          * between the inode and its parent if the inode is fsync'ed and the log
3692          * replayed. For example, in the scenario:
3693          *
3694          * touch mydir/foo
3695          * ln mydir/foo mydir/bar
3696          * sync
3697          * unlink mydir/bar
3698          * echo 2 > /proc/sys/vm/drop_caches   # evicts inode
3699          * xfs_io -c fsync mydir/foo
3700          * <power failure>
3701          * mount fs, triggers fsync log replay
3702          *
3703          * We must make sure that when we fsync our inode foo we also log its
3704          * parent inode, otherwise after log replay the parent still has the
3705          * dentry with the "bar" name but our inode foo has a link count of 1
3706          * and doesn't have an inode ref with the name "bar" anymore.
3707          *
3708          * Setting last_unlink_trans to last_trans is a pessimistic approach,
3709          * but it guarantees correctness at the expense of ocassional full
3710          * transaction commits on fsync if our inode is a directory, or if our
3711          * inode is not a directory, logging its parent unnecessarily.
3712          */
3713         BTRFS_I(inode)->last_unlink_trans = BTRFS_I(inode)->last_trans;
3714
3715         path->slots[0]++;
3716         if (inode->i_nlink != 1 ||
3717             path->slots[0] >= btrfs_header_nritems(leaf))
3718                 goto cache_acl;
3719
3720         btrfs_item_key_to_cpu(leaf, &location, path->slots[0]);
3721         if (location.objectid != btrfs_ino(inode))
3722                 goto cache_acl;
3723
3724         ptr = btrfs_item_ptr_offset(leaf, path->slots[0]);
3725         if (location.type == BTRFS_INODE_REF_KEY) {
3726                 struct btrfs_inode_ref *ref;
3727
3728                 ref = (struct btrfs_inode_ref *)ptr;
3729                 BTRFS_I(inode)->dir_index = btrfs_inode_ref_index(leaf, ref);
3730         } else if (location.type == BTRFS_INODE_EXTREF_KEY) {
3731                 struct btrfs_inode_extref *extref;
3732
3733                 extref = (struct btrfs_inode_extref *)ptr;
3734                 BTRFS_I(inode)->dir_index = btrfs_inode_extref_index(leaf,
3735                                                                      extref);
3736         }
3737 cache_acl:
3738         /*
3739          * try to precache a NULL acl entry for files that don't have
3740          * any xattrs or acls
3741          */
3742         maybe_acls = acls_after_inode_item(leaf, path->slots[0],
3743                                            btrfs_ino(inode), &first_xattr_slot);
3744         if (first_xattr_slot != -1) {
3745                 path->slots[0] = first_xattr_slot;
3746                 ret = btrfs_load_inode_props(inode, path);
3747                 if (ret)
3748                         btrfs_err(root->fs_info,
3749                                   "error loading props for ino %llu (root %llu): %d",
3750                                   btrfs_ino(inode),
3751                                   root->root_key.objectid, ret);
3752         }
3753         btrfs_free_path(path);
3754
3755         if (!maybe_acls)
3756                 cache_no_acl(inode);
3757
3758         switch (inode->i_mode & S_IFMT) {
3759         case S_IFREG:
3760                 inode->i_mapping->a_ops = &btrfs_aops;
3761                 BTRFS_I(inode)->io_tree.ops = &btrfs_extent_io_ops;
3762                 inode->i_fop = &btrfs_file_operations;
3763                 inode->i_op = &btrfs_file_inode_operations;
3764                 break;
3765         case S_IFDIR:
3766                 inode->i_fop = &btrfs_dir_file_operations;
3767                 if (root == root->fs_info->tree_root)
3768                         inode->i_op = &btrfs_dir_ro_inode_operations;
3769                 else
3770                         inode->i_op = &btrfs_dir_inode_operations;
3771                 break;
3772         case S_IFLNK:
3773                 inode->i_op = &btrfs_symlink_inode_operations;
3774                 inode_nohighmem(inode);
3775                 inode->i_mapping->a_ops = &btrfs_symlink_aops;
3776                 break;
3777         default:
3778                 inode->i_op = &btrfs_special_inode_operations;
3779                 init_special_inode(inode, inode->i_mode, rdev);
3780                 break;
3781         }
3782
3783         btrfs_update_iflags(inode);
3784         return;
3785
3786 make_bad:
3787         btrfs_free_path(path);
3788         make_bad_inode(inode);
3789 }
3790
3791 /*
3792  * given a leaf and an inode, copy the inode fields into the leaf
3793  */
3794 static void fill_inode_item(struct btrfs_trans_handle *trans,
3795                             struct extent_buffer *leaf,
3796                             struct btrfs_inode_item *item,
3797                             struct inode *inode)
3798 {
3799         struct btrfs_map_token token;
3800
3801         btrfs_init_map_token(&token);
3802
3803         btrfs_set_token_inode_uid(leaf, item, i_uid_read(inode), &token);
3804         btrfs_set_token_inode_gid(leaf, item, i_gid_read(inode), &token);
3805         btrfs_set_token_inode_size(leaf, item, BTRFS_I(inode)->disk_i_size,
3806                                    &token);
3807         btrfs_set_token_inode_mode(leaf, item, inode->i_mode, &token);
3808         btrfs_set_token_inode_nlink(leaf, item, inode->i_nlink, &token);
3809
3810         btrfs_set_token_timespec_sec(leaf, &item->atime,
3811                                      inode->i_atime.tv_sec, &token);
3812         btrfs_set_token_timespec_nsec(leaf, &item->atime,
3813                                       inode->i_atime.tv_nsec, &token);
3814
3815         btrfs_set_token_timespec_sec(leaf, &item->mtime,
3816                                      inode->i_mtime.tv_sec, &token);
3817         btrfs_set_token_timespec_nsec(leaf, &item->mtime,
3818                                       inode->i_mtime.tv_nsec, &token);
3819
3820         btrfs_set_token_timespec_sec(leaf, &item->ctime,
3821                                      inode->i_ctime.tv_sec, &token);
3822         btrfs_set_token_timespec_nsec(leaf, &item->ctime,
3823                                       inode->i_ctime.tv_nsec, &token);
3824
3825         btrfs_set_token_timespec_sec(leaf, &item->otime,
3826                                      BTRFS_I(inode)->i_otime.tv_sec, &token);
3827         btrfs_set_token_timespec_nsec(leaf, &item->otime,
3828                                       BTRFS_I(inode)->i_otime.tv_nsec, &token);
3829
3830         btrfs_set_token_inode_nbytes(leaf, item, inode_get_bytes(inode),
3831                                      &token);
3832         btrfs_set_token_inode_generation(leaf, item, BTRFS_I(inode)->generation,
3833                                          &token);
3834         btrfs_set_token_inode_sequence(leaf, item, inode->i_version, &token);
3835         btrfs_set_token_inode_transid(leaf, item, trans->transid, &token);
3836         btrfs_set_token_inode_rdev(leaf, item, inode->i_rdev, &token);
3837         btrfs_set_token_inode_flags(leaf, item, BTRFS_I(inode)->flags, &token);
3838         btrfs_set_token_inode_block_group(leaf, item, 0, &token);
3839 }
3840
3841 /*
3842  * copy everything in the in-memory inode into the btree.
3843  */
3844 static noinline int btrfs_update_inode_item(struct btrfs_trans_handle *trans,
3845                                 struct btrfs_root *root, struct inode *inode)
3846 {
3847         struct btrfs_inode_item *inode_item;
3848         struct btrfs_path *path;
3849         struct extent_buffer *leaf;
3850         int ret;
3851
3852         path = btrfs_alloc_path();
3853         if (!path)
3854                 return -ENOMEM;
3855
3856         path->leave_spinning = 1;
3857         ret = btrfs_lookup_inode(trans, root, path, &BTRFS_I(inode)->location,
3858                                  1);
3859         if (ret) {
3860                 if (ret > 0)
3861                         ret = -ENOENT;
3862                 goto failed;
3863         }
3864
3865         leaf = path->nodes[0];
3866         inode_item = btrfs_item_ptr(leaf, path->slots[0],
3867                                     struct btrfs_inode_item);
3868
3869         fill_inode_item(trans, leaf, inode_item, inode);
3870         btrfs_mark_buffer_dirty(leaf);
3871         btrfs_set_inode_last_trans(trans, inode);
3872         ret = 0;
3873 failed:
3874         btrfs_free_path(path);
3875         return ret;
3876 }
3877
3878 /*
3879  * copy everything in the in-memory inode into the btree.
3880  */
3881 noinline int btrfs_update_inode(struct btrfs_trans_handle *trans,
3882                                 struct btrfs_root *root, struct inode *inode)
3883 {
3884         int ret;
3885
3886         /*
3887          * If the inode is a free space inode, we can deadlock during commit
3888          * if we put it into the delayed code.
3889          *
3890          * The data relocation inode should also be directly updated
3891          * without delay
3892          */
3893         if (!btrfs_is_free_space_inode(inode)
3894             && root->root_key.objectid != BTRFS_DATA_RELOC_TREE_OBJECTID
3895             && !root->fs_info->log_root_recovering) {
3896                 btrfs_update_root_times(trans, root);
3897
3898                 ret = btrfs_delayed_update_inode(trans, root, inode);
3899                 if (!ret)
3900                         btrfs_set_inode_last_trans(trans, inode);
3901                 return ret;
3902         }
3903
3904         return btrfs_update_inode_item(trans, root, inode);
3905 }
3906
3907 noinline int btrfs_update_inode_fallback(struct btrfs_trans_handle *trans,
3908                                          struct btrfs_root *root,
3909                                          struct inode *inode)
3910 {
3911         int ret;
3912
3913         ret = btrfs_update_inode(trans, root, inode);
3914         if (ret == -ENOSPC)
3915                 return btrfs_update_inode_item(trans, root, inode);
3916         return ret;
3917 }
3918
3919 /*
3920  * unlink helper that gets used here in inode.c and in the tree logging
3921  * recovery code.  It remove a link in a directory with a given name, and
3922  * also drops the back refs in the inode to the directory
3923  */
3924 static int __btrfs_unlink_inode(struct btrfs_trans_handle *trans,
3925                                 struct btrfs_root *root,
3926                                 struct inode *dir, struct inode *inode,
3927                                 const char *name, int name_len)
3928 {
3929         struct btrfs_path *path;
3930         int ret = 0;
3931         struct extent_buffer *leaf;
3932         struct btrfs_dir_item *di;
3933         struct btrfs_key key;
3934         u64 index;
3935         u64 ino = btrfs_ino(inode);
3936         u64 dir_ino = btrfs_ino(dir);
3937
3938         path = btrfs_alloc_path();
3939         if (!path) {
3940                 ret = -ENOMEM;
3941                 goto out;
3942         }
3943
3944         path->leave_spinning = 1;
3945         di = btrfs_lookup_dir_item(trans, root, path, dir_ino,
3946                                     name, name_len, -1);
3947         if (IS_ERR(di)) {
3948                 ret = PTR_ERR(di);
3949                 goto err;
3950         }
3951         if (!di) {
3952                 ret = -ENOENT;
3953                 goto err;
3954         }
3955         leaf = path->nodes[0];
3956         btrfs_dir_item_key_to_cpu(leaf, di, &key);
3957         ret = btrfs_delete_one_dir_name(trans, root, path, di);
3958         if (ret)
3959                 goto err;
3960         btrfs_release_path(path);
3961
3962         /*
3963          * If we don't have dir index, we have to get it by looking up
3964          * the inode ref, since we get the inode ref, remove it directly,
3965          * it is unnecessary to do delayed deletion.
3966          *
3967          * But if we have dir index, needn't search inode ref to get it.
3968          * Since the inode ref is close to the inode item, it is better
3969          * that we delay to delete it, and just do this deletion when
3970          * we update the inode item.
3971          */
3972         if (BTRFS_I(inode)->dir_index) {
3973                 ret = btrfs_delayed_delete_inode_ref(inode);
3974                 if (!ret) {
3975                         index = BTRFS_I(inode)->dir_index;
3976                         goto skip_backref;
3977                 }
3978         }
3979
3980         ret = btrfs_del_inode_ref(trans, root, name, name_len, ino,
3981                                   dir_ino, &index);
3982         if (ret) {
3983                 btrfs_info(root->fs_info,
3984                         "failed to delete reference to %.*s, inode %llu parent %llu",
3985                         name_len, name, ino, dir_ino);
3986                 btrfs_abort_transaction(trans, root, ret);
3987                 goto err;
3988         }
3989 skip_backref:
3990         ret = btrfs_delete_delayed_dir_index(trans, root, dir, index);
3991         if (ret) {
3992                 btrfs_abort_transaction(trans, root, ret);
3993                 goto err;
3994         }
3995
3996         ret = btrfs_del_inode_ref_in_log(trans, root, name, name_len,
3997                                          inode, dir_ino);
3998         if (ret != 0 && ret != -ENOENT) {
3999                 btrfs_abort_transaction(trans, root, ret);
4000                 goto err;
4001         }
4002
4003         ret = btrfs_del_dir_entries_in_log(trans, root, name, name_len,
4004                                            dir, index);
4005         if (ret == -ENOENT)
4006                 ret = 0;
4007         else if (ret)
4008                 btrfs_abort_transaction(trans, root, ret);
4009 err:
4010         btrfs_free_path(path);
4011         if (ret)
4012                 goto out;
4013
4014         btrfs_i_size_write(dir, dir->i_size - name_len * 2);
4015         inode_inc_iversion(inode);
4016         inode_inc_iversion(dir);
4017         inode->i_ctime = dir->i_mtime =
4018                 dir->i_ctime = current_fs_time(inode->i_sb);
4019         ret = btrfs_update_inode(trans, root, dir);
4020 out:
4021         return ret;
4022 }
4023
4024 int btrfs_unlink_inode(struct btrfs_trans_handle *trans,
4025                        struct btrfs_root *root,
4026                        struct inode *dir, struct inode *inode,
4027                        const char *name, int name_len)
4028 {
4029         int ret;
4030         ret = __btrfs_unlink_inode(trans, root, dir, inode, name, name_len);
4031         if (!ret) {
4032                 drop_nlink(inode);
4033                 ret = btrfs_update_inode(trans, root, inode);
4034         }
4035         return ret;
4036 }
4037
4038 /*
4039  * helper to start transaction for unlink and rmdir.
4040  *
4041  * unlink and rmdir are special in btrfs, they do not always free space, so
4042  * if we cannot make our reservations the normal way try and see if there is
4043  * plenty of slack room in the global reserve to migrate, otherwise we cannot
4044  * allow the unlink to occur.
4045  */
4046 static struct btrfs_trans_handle *__unlink_start_trans(struct inode *dir)
4047 {
4048         struct btrfs_root *root = BTRFS_I(dir)->root;
4049
4050         /*
4051          * 1 for the possible orphan item
4052          * 1 for the dir item
4053          * 1 for the dir index
4054          * 1 for the inode ref
4055          * 1 for the inode
4056          */
4057         return btrfs_start_transaction_fallback_global_rsv(root, 5, 5);
4058 }
4059
4060 static int btrfs_unlink(struct inode *dir, struct dentry *dentry)
4061 {
4062         struct btrfs_root *root = BTRFS_I(dir)->root;
4063         struct btrfs_trans_handle *trans;
4064         struct inode *inode = d_inode(dentry);
4065         int ret;
4066
4067         trans = __unlink_start_trans(dir);
4068         if (IS_ERR(trans))
4069                 return PTR_ERR(trans);
4070
4071         btrfs_record_unlink_dir(trans, dir, d_inode(dentry), 0);
4072
4073         ret = btrfs_unlink_inode(trans, root, dir, d_inode(dentry),
4074                                  dentry->d_name.name, dentry->d_name.len);
4075         if (ret)
4076                 goto out;
4077
4078         if (inode->i_nlink == 0) {
4079                 ret = btrfs_orphan_add(trans, inode);
4080                 if (ret)
4081                         goto out;
4082         }
4083
4084 out:
4085         btrfs_end_transaction(trans, root);
4086         btrfs_btree_balance_dirty(root);
4087         return ret;
4088 }
4089
4090 int btrfs_unlink_subvol(struct btrfs_trans_handle *trans,
4091                         struct btrfs_root *root,
4092                         struct inode *dir, u64 objectid,
4093                         const char *name, int name_len)
4094 {
4095         struct btrfs_path *path;
4096         struct extent_buffer *leaf;
4097         struct btrfs_dir_item *di;
4098         struct btrfs_key key;
4099         u64 index;
4100         int ret;
4101         u64 dir_ino = btrfs_ino(dir);
4102
4103         path = btrfs_alloc_path();
4104         if (!path)
4105                 return -ENOMEM;
4106
4107         di = btrfs_lookup_dir_item(trans, root, path, dir_ino,
4108                                    name, name_len, -1);
4109         if (IS_ERR_OR_NULL(di)) {
4110                 if (!di)
4111                         ret = -ENOENT;
4112                 else
4113                         ret = PTR_ERR(di);
4114                 goto out;
4115         }
4116
4117         leaf = path->nodes[0];
4118         btrfs_dir_item_key_to_cpu(leaf, di, &key);
4119         WARN_ON(key.type != BTRFS_ROOT_ITEM_KEY || key.objectid != objectid);
4120         ret = btrfs_delete_one_dir_name(trans, root, path, di);
4121         if (ret) {
4122                 btrfs_abort_transaction(trans, root, ret);
4123                 goto out;
4124         }
4125         btrfs_release_path(path);
4126
4127         ret = btrfs_del_root_ref(trans, root->fs_info->tree_root,
4128                                  objectid, root->root_key.objectid,
4129                                  dir_ino, &index, name, name_len);
4130         if (ret < 0) {
4131                 if (ret != -ENOENT) {
4132                         btrfs_abort_transaction(trans, root, ret);
4133                         goto out;
4134                 }
4135                 di = btrfs_search_dir_index_item(root, path, dir_ino,
4136                                                  name, name_len);
4137                 if (IS_ERR_OR_NULL(di)) {
4138                         if (!di)
4139                                 ret = -ENOENT;
4140                         else
4141                                 ret = PTR_ERR(di);
4142                         btrfs_abort_transaction(trans, root, ret);
4143                         goto out;
4144                 }
4145
4146                 leaf = path->nodes[0];
4147                 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
4148                 btrfs_release_path(path);
4149                 index = key.offset;
4150         }
4151         btrfs_release_path(path);
4152
4153         ret = btrfs_delete_delayed_dir_index(trans, root, dir, index);
4154         if (ret) {
4155                 btrfs_abort_transaction(trans, root, ret);
4156                 goto out;
4157         }
4158
4159         btrfs_i_size_write(dir, dir->i_size - name_len * 2);
4160         inode_inc_iversion(dir);
4161         dir->i_mtime = dir->i_ctime = current_fs_time(dir->i_sb);
4162         ret = btrfs_update_inode_fallback(trans, root, dir);
4163         if (ret)
4164                 btrfs_abort_transaction(trans, root, ret);
4165 out:
4166         btrfs_free_path(path);
4167         return ret;
4168 }
4169
4170 static int btrfs_rmdir(struct inode *dir, struct dentry *dentry)
4171 {
4172         struct inode *inode = d_inode(dentry);
4173         int err = 0;
4174         struct btrfs_root *root = BTRFS_I(dir)->root;
4175         struct btrfs_trans_handle *trans;
4176
4177         if (inode->i_size > BTRFS_EMPTY_DIR_SIZE)
4178                 return -ENOTEMPTY;
4179         if (btrfs_ino(inode) == BTRFS_FIRST_FREE_OBJECTID)
4180                 return -EPERM;
4181
4182         trans = __unlink_start_trans(dir);
4183         if (IS_ERR(trans))
4184                 return PTR_ERR(trans);
4185
4186         if (unlikely(btrfs_ino(inode) == BTRFS_EMPTY_SUBVOL_DIR_OBJECTID)) {
4187                 err = btrfs_unlink_subvol(trans, root, dir,
4188                                           BTRFS_I(inode)->location.objectid,
4189                                           dentry->d_name.name,
4190                                           dentry->d_name.len);
4191                 goto out;
4192         }
4193
4194         err = btrfs_orphan_add(trans, inode);
4195         if (err)
4196                 goto out;
4197
4198         /* now the directory is empty */
4199         err = btrfs_unlink_inode(trans, root, dir, d_inode(dentry),
4200                                  dentry->d_name.name, dentry->d_name.len);
4201         if (!err)
4202                 btrfs_i_size_write(inode, 0);
4203 out:
4204         btrfs_end_transaction(trans, root);
4205         btrfs_btree_balance_dirty(root);
4206
4207         return err;
4208 }
4209
4210 static int truncate_space_check(struct btrfs_trans_handle *trans,
4211                                 struct btrfs_root *root,
4212                                 u64 bytes_deleted)
4213 {
4214         int ret;
4215
4216         /*
4217          * This is only used to apply pressure to the enospc system, we don't
4218          * intend to use this reservation at all.
4219          */
4220         bytes_deleted = btrfs_csum_bytes_to_leaves(root, bytes_deleted);
4221         bytes_deleted *= root->nodesize;
4222         ret = btrfs_block_rsv_add(root, &root->fs_info->trans_block_rsv,
4223                                   bytes_deleted, BTRFS_RESERVE_NO_FLUSH);
4224         if (!ret) {
4225                 trace_btrfs_space_reservation(root->fs_info, "transaction",
4226                                               trans->transid,
4227                                               bytes_deleted, 1);
4228                 trans->bytes_reserved += bytes_deleted;
4229         }
4230         return ret;
4231
4232 }
4233
4234 static int truncate_inline_extent(struct inode *inode,
4235                                   struct btrfs_path *path,
4236                                   struct btrfs_key *found_key,
4237                                   const u64 item_end,
4238                                   const u64 new_size)
4239 {
4240         struct extent_buffer *leaf = path->nodes[0];
4241         int slot = path->slots[0];
4242         struct btrfs_file_extent_item *fi;
4243         u32 size = (u32)(new_size - found_key->offset);
4244         struct btrfs_root *root = BTRFS_I(inode)->root;
4245
4246         fi = btrfs_item_ptr(leaf, slot, struct btrfs_file_extent_item);
4247
4248         if (btrfs_file_extent_compression(leaf, fi) != BTRFS_COMPRESS_NONE) {
4249                 loff_t offset = new_size;
4250                 loff_t page_end = ALIGN(offset, PAGE_SIZE);
4251
4252                 /*
4253                  * Zero out the remaining of the last page of our inline extent,
4254                  * instead of directly truncating our inline extent here - that
4255                  * would be much more complex (decompressing all the data, then
4256                  * compressing the truncated data, which might be bigger than
4257                  * the size of the inline extent, resize the extent, etc).
4258                  * We release the path because to get the page we might need to
4259                  * read the extent item from disk (data not in the page cache).
4260                  */
4261                 btrfs_release_path(path);
4262                 return btrfs_truncate_block(inode, offset, page_end - offset,
4263                                         0);
4264         }
4265
4266         btrfs_set_file_extent_ram_bytes(leaf, fi, size);
4267         size = btrfs_file_extent_calc_inline_size(size);
4268         btrfs_truncate_item(root, path, size, 1);
4269
4270         if (test_bit(BTRFS_ROOT_REF_COWS, &root->state))
4271                 inode_sub_bytes(inode, item_end + 1 - new_size);
4272
4273         return 0;
4274 }
4275
4276 /*
4277  * this can truncate away extent items, csum items and directory items.
4278  * It starts at a high offset and removes keys until it can't find
4279  * any higher than new_size
4280  *
4281  * csum items that cross the new i_size are truncated to the new size
4282  * as well.
4283  *
4284  * min_type is the minimum key type to truncate down to.  If set to 0, this
4285  * will kill all the items on this inode, including the INODE_ITEM_KEY.
4286  */
4287 int btrfs_truncate_inode_items(struct btrfs_trans_handle *trans,
4288                                struct btrfs_root *root,
4289                                struct inode *inode,
4290                                u64 new_size, u32 min_type)
4291 {
4292         struct btrfs_path *path;
4293         struct extent_buffer *leaf;
4294         struct btrfs_file_extent_item *fi;
4295         struct btrfs_key key;
4296         struct btrfs_key found_key;
4297         u64 extent_start = 0;
4298         u64 extent_num_bytes = 0;
4299         u64 extent_offset = 0;
4300         u64 item_end = 0;
4301         u64 last_size = new_size;
4302         u32 found_type = (u8)-1;
4303         int found_extent;
4304         int del_item;
4305         int pending_del_nr = 0;
4306         int pending_del_slot = 0;
4307         int extent_type = -1;
4308         int ret;
4309         int err = 0;
4310         u64 ino = btrfs_ino(inode);
4311         u64 bytes_deleted = 0;
4312         bool be_nice = 0;
4313         bool should_throttle = 0;
4314         bool should_end = 0;
4315
4316         BUG_ON(new_size > 0 && min_type != BTRFS_EXTENT_DATA_KEY);
4317
4318         /*
4319          * for non-free space inodes and ref cows, we want to back off from
4320          * time to time
4321          */
4322         if (!btrfs_is_free_space_inode(inode) &&
4323             test_bit(BTRFS_ROOT_REF_COWS, &root->state))
4324                 be_nice = 1;
4325
4326         path = btrfs_alloc_path();
4327         if (!path)
4328                 return -ENOMEM;
4329         path->reada = READA_BACK;
4330
4331         /*
4332          * We want to drop from the next block forward in case this new size is
4333          * not block aligned since we will be keeping the last block of the
4334          * extent just the way it is.
4335          */
4336         if (test_bit(BTRFS_ROOT_REF_COWS, &root->state) ||
4337             root == root->fs_info->tree_root)
4338                 btrfs_drop_extent_cache(inode, ALIGN(new_size,
4339                                         root->sectorsize), (u64)-1, 0);
4340
4341         /*
4342          * This function is also used to drop the items in the log tree before
4343          * we relog the inode, so if root != BTRFS_I(inode)->root, it means
4344          * it is used to drop the loged items. So we shouldn't kill the delayed
4345          * items.
4346          */
4347         if (min_type == 0 && root == BTRFS_I(inode)->root)
4348                 btrfs_kill_delayed_inode_items(inode);
4349
4350         key.objectid = ino;
4351         key.offset = (u64)-1;
4352         key.type = (u8)-1;
4353
4354 search_again:
4355         /*
4356          * with a 16K leaf size and 128MB extents, you can actually queue
4357          * up a huge file in a single leaf.  Most of the time that
4358          * bytes_deleted is > 0, it will be huge by the time we get here
4359          */
4360         if (be_nice && bytes_deleted > SZ_32M) {
4361                 if (btrfs_should_end_transaction(trans, root)) {
4362                         err = -EAGAIN;
4363                         goto error;
4364                 }
4365         }
4366
4367
4368         path->leave_spinning = 1;
4369         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
4370         if (ret < 0) {
4371                 err = ret;
4372                 goto out;
4373         }
4374
4375         if (ret > 0) {
4376                 /* there are no items in the tree for us to truncate, we're
4377                  * done
4378                  */
4379                 if (path->slots[0] == 0)
4380                         goto out;
4381                 path->slots[0]--;
4382         }
4383
4384         while (1) {
4385                 fi = NULL;
4386                 leaf = path->nodes[0];
4387                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
4388                 found_type = found_key.type;
4389
4390                 if (found_key.objectid != ino)
4391                         break;
4392
4393                 if (found_type < min_type)
4394                         break;
4395
4396                 item_end = found_key.offset;
4397                 if (found_type == BTRFS_EXTENT_DATA_KEY) {
4398                         fi = btrfs_item_ptr(leaf, path->slots[0],
4399                                             struct btrfs_file_extent_item);
4400                         extent_type = btrfs_file_extent_type(leaf, fi);
4401                         if (extent_type != BTRFS_FILE_EXTENT_INLINE) {
4402                                 item_end +=
4403                                     btrfs_file_extent_num_bytes(leaf, fi);
4404                         } else if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
4405                                 item_end += btrfs_file_extent_inline_len(leaf,
4406                                                          path->slots[0], fi);
4407                         }
4408                         item_end--;
4409                 }
4410                 if (found_type > min_type) {
4411                         del_item = 1;
4412                 } else {
4413                         if (item_end < new_size)
4414                                 break;
4415                         if (found_key.offset >= new_size)
4416                                 del_item = 1;
4417                         else
4418                                 del_item = 0;
4419                 }
4420                 found_extent = 0;
4421                 /* FIXME, shrink the extent if the ref count is only 1 */
4422                 if (found_type != BTRFS_EXTENT_DATA_KEY)
4423                         goto delete;
4424
4425                 if (del_item)
4426                         last_size = found_key.offset;
4427                 else
4428                         last_size = new_size;
4429
4430                 if (extent_type != BTRFS_FILE_EXTENT_INLINE) {
4431                         u64 num_dec;
4432                         extent_start = btrfs_file_extent_disk_bytenr(leaf, fi);
4433                         if (!del_item) {
4434                                 u64 orig_num_bytes =
4435                                         btrfs_file_extent_num_bytes(leaf, fi);
4436                                 extent_num_bytes = ALIGN(new_size -
4437                                                 found_key.offset,
4438                                                 root->sectorsize);
4439                                 btrfs_set_file_extent_num_bytes(leaf, fi,
4440                                                          extent_num_bytes);
4441                                 num_dec = (orig_num_bytes -
4442                                            extent_num_bytes);
4443                                 if (test_bit(BTRFS_ROOT_REF_COWS,
4444                                              &root->state) &&
4445                                     extent_start != 0)
4446                                         inode_sub_bytes(inode, num_dec);
4447                                 btrfs_mark_buffer_dirty(leaf);
4448                         } else {
4449                                 extent_num_bytes =
4450                                         btrfs_file_extent_disk_num_bytes(leaf,
4451                                                                          fi);
4452                                 extent_offset = found_key.offset -
4453                                         btrfs_file_extent_offset(leaf, fi);
4454
4455                                 /* FIXME blocksize != 4096 */
4456                                 num_dec = btrfs_file_extent_num_bytes(leaf, fi);
4457                                 if (extent_start != 0) {
4458                                         found_extent = 1;
4459                                         if (test_bit(BTRFS_ROOT_REF_COWS,
4460                                                      &root->state))
4461                                                 inode_sub_bytes(inode, num_dec);
4462                                 }
4463                         }
4464                 } else if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
4465                         /*
4466                          * we can't truncate inline items that have had
4467                          * special encodings
4468                          */
4469                         if (!del_item &&
4470                             btrfs_file_extent_encryption(leaf, fi) == 0 &&
4471                             btrfs_file_extent_other_encoding(leaf, fi) == 0) {
4472
4473                                 /*
4474                                  * Need to release path in order to truncate a
4475                                  * compressed extent. So delete any accumulated
4476                                  * extent items so far.
4477                                  */
4478                                 if (btrfs_file_extent_compression(leaf, fi) !=
4479                                     BTRFS_COMPRESS_NONE && pending_del_nr) {
4480                                         err = btrfs_del_items(trans, root, path,
4481                                                               pending_del_slot,
4482                                                               pending_del_nr);
4483                                         if (err) {
4484                                                 btrfs_abort_transaction(trans,
4485                                                                         root,
4486                                                                         err);
4487                                                 goto error;
4488                                         }
4489                                         pending_del_nr = 0;
4490                                 }
4491
4492                                 err = truncate_inline_extent(inode, path,
4493                                                              &found_key,
4494                                                              item_end,
4495                                                              new_size);
4496                                 if (err) {
4497                                         btrfs_abort_transaction(trans,
4498                                                                 root, err);
4499                                         goto error;
4500                                 }
4501                         } else if (test_bit(BTRFS_ROOT_REF_COWS,
4502                                             &root->state)) {
4503                                 inode_sub_bytes(inode, item_end + 1 - new_size);
4504                         }
4505                 }
4506 delete:
4507                 if (del_item) {
4508                         if (!pending_del_nr) {
4509                                 /* no pending yet, add ourselves */
4510                                 pending_del_slot = path->slots[0];
4511                                 pending_del_nr = 1;
4512                         } else if (pending_del_nr &&
4513                                    path->slots[0] + 1 == pending_del_slot) {
4514                                 /* hop on the pending chunk */
4515                                 pending_del_nr++;
4516                                 pending_del_slot = path->slots[0];
4517                         } else {
4518                                 BUG();
4519                         }
4520                 } else {
4521                         break;
4522                 }
4523                 should_throttle = 0;
4524
4525                 if (found_extent &&
4526                     (test_bit(BTRFS_ROOT_REF_COWS, &root->state) ||
4527                      root == root->fs_info->tree_root)) {
4528                         btrfs_set_path_blocking(path);
4529                         bytes_deleted += extent_num_bytes;
4530                         ret = btrfs_free_extent(trans, root, extent_start,
4531                                                 extent_num_bytes, 0,
4532                                                 btrfs_header_owner(leaf),
4533                                                 ino, extent_offset);
4534                         BUG_ON(ret);
4535                         if (btrfs_should_throttle_delayed_refs(trans, root))
4536                                 btrfs_async_run_delayed_refs(root,
4537                                         trans->delayed_ref_updates * 2, 0);
4538                         if (be_nice) {
4539                                 if (truncate_space_check(trans, root,
4540                                                          extent_num_bytes)) {
4541                                         should_end = 1;
4542                                 }
4543                                 if (btrfs_should_throttle_delayed_refs(trans,
4544                                                                        root)) {
4545                                         should_throttle = 1;
4546                                 }
4547                         }
4548                 }
4549
4550                 if (found_type == BTRFS_INODE_ITEM_KEY)
4551                         break;
4552
4553                 if (path->slots[0] == 0 ||
4554                     path->slots[0] != pending_del_slot ||
4555                     should_throttle || should_end) {
4556                         if (pending_del_nr) {
4557                                 ret = btrfs_del_items(trans, root, path,
4558                                                 pending_del_slot,
4559                                                 pending_del_nr);
4560                                 if (ret) {
4561                                         btrfs_abort_transaction(trans,
4562                                                                 root, ret);
4563                                         goto error;
4564                                 }
4565                                 pending_del_nr = 0;
4566                         }
4567                         btrfs_release_path(path);
4568                         if (should_throttle) {
4569                                 unsigned long updates = trans->delayed_ref_updates;
4570                                 if (updates) {
4571                                         trans->delayed_ref_updates = 0;
4572                                         ret = btrfs_run_delayed_refs(trans, root, updates * 2);
4573                                         if (ret && !err)
4574                                                 err = ret;
4575                                 }
4576                         }
4577                         /*
4578                          * if we failed to refill our space rsv, bail out
4579                          * and let the transaction restart
4580                          */
4581                         if (should_end) {
4582                                 err = -EAGAIN;
4583                                 goto error;
4584                         }
4585                         goto search_again;
4586                 } else {
4587                         path->slots[0]--;
4588                 }
4589         }
4590 out:
4591         if (pending_del_nr) {
4592                 ret = btrfs_del_items(trans, root, path, pending_del_slot,
4593                                       pending_del_nr);
4594                 if (ret)
4595                         btrfs_abort_transaction(trans, root, ret);
4596         }
4597 error:
4598         if (root->root_key.objectid != BTRFS_TREE_LOG_OBJECTID)
4599                 btrfs_ordered_update_i_size(inode, last_size, NULL);
4600
4601         btrfs_free_path(path);
4602
4603         if (be_nice && bytes_deleted > SZ_32M) {
4604                 unsigned long updates = trans->delayed_ref_updates;
4605                 if (updates) {
4606                         trans->delayed_ref_updates = 0;
4607                         ret = btrfs_run_delayed_refs(trans, root, updates * 2);
4608                         if (ret && !err)
4609                                 err = ret;
4610                 }
4611         }
4612         return err;
4613 }
4614
4615 /*
4616  * btrfs_truncate_block - read, zero a chunk and write a block
4617  * @inode - inode that we're zeroing
4618  * @from - the offset to start zeroing
4619  * @len - the length to zero, 0 to zero the entire range respective to the
4620  *      offset
4621  * @front - zero up to the offset instead of from the offset on
4622  *
4623  * This will find the block for the "from" offset and cow the block and zero the
4624  * part we want to zero.  This is used with truncate and hole punching.
4625  */
4626 int btrfs_truncate_block(struct inode *inode, loff_t from, loff_t len,
4627                         int front)
4628 {
4629         struct address_space *mapping = inode->i_mapping;
4630         struct btrfs_root *root = BTRFS_I(inode)->root;
4631         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
4632         struct btrfs_ordered_extent *ordered;
4633         struct extent_state *cached_state = NULL;
4634         char *kaddr;
4635         u32 blocksize = root->sectorsize;
4636         pgoff_t index = from >> PAGE_SHIFT;
4637         unsigned offset = from & (blocksize - 1);
4638         struct page *page;
4639         gfp_t mask = btrfs_alloc_write_mask(mapping);
4640         int ret = 0;
4641         u64 block_start;
4642         u64 block_end;
4643
4644         if ((offset & (blocksize - 1)) == 0 &&
4645             (!len || ((len & (blocksize - 1)) == 0)))
4646                 goto out;
4647
4648         ret = btrfs_delalloc_reserve_space(inode,
4649                         round_down(from, blocksize), blocksize);
4650         if (ret)
4651                 goto out;
4652
4653 again:
4654         page = find_or_create_page(mapping, index, mask);
4655         if (!page) {
4656                 btrfs_delalloc_release_space(inode,
4657                                 round_down(from, blocksize),
4658                                 blocksize);
4659                 ret = -ENOMEM;
4660                 goto out;
4661         }
4662
4663         block_start = round_down(from, blocksize);
4664         block_end = block_start + blocksize - 1;
4665
4666         if (!PageUptodate(page)) {
4667                 ret = btrfs_readpage(NULL, page);
4668                 lock_page(page);
4669                 if (page->mapping != mapping) {
4670                         unlock_page(page);
4671                         put_page(page);
4672                         goto again;
4673                 }
4674                 if (!PageUptodate(page)) {
4675                         ret = -EIO;
4676                         goto out_unlock;
4677                 }
4678         }
4679         wait_on_page_writeback(page);
4680
4681         lock_extent_bits(io_tree, block_start, block_end, &cached_state);
4682         set_page_extent_mapped(page);
4683
4684         ordered = btrfs_lookup_ordered_extent(inode, block_start);
4685         if (ordered) {
4686                 unlock_extent_cached(io_tree, block_start, block_end,
4687                                      &cached_state, GFP_NOFS);
4688                 unlock_page(page);
4689                 put_page(page);
4690                 btrfs_start_ordered_extent(inode, ordered, 1);
4691                 btrfs_put_ordered_extent(ordered);
4692                 goto again;
4693         }
4694
4695         clear_extent_bit(&BTRFS_I(inode)->io_tree, block_start, block_end,
4696                           EXTENT_DIRTY | EXTENT_DELALLOC |
4697                           EXTENT_DO_ACCOUNTING | EXTENT_DEFRAG,
4698                           0, 0, &cached_state, GFP_NOFS);
4699
4700         ret = btrfs_set_extent_delalloc(inode, block_start, block_end,
4701                                         &cached_state);
4702         if (ret) {
4703                 unlock_extent_cached(io_tree, block_start, block_end,
4704                                      &cached_state, GFP_NOFS);
4705                 goto out_unlock;
4706         }
4707
4708         if (offset != blocksize) {
4709                 if (!len)
4710                         len = blocksize - offset;
4711                 kaddr = kmap(page);
4712                 if (front)
4713                         memset(kaddr + (block_start - page_offset(page)),
4714                                 0, offset);
4715                 else
4716                         memset(kaddr + (block_start - page_offset(page)) +  offset,
4717                                 0, len);
4718                 flush_dcache_page(page);
4719                 kunmap(page);
4720         }
4721         ClearPageChecked(page);
4722         set_page_dirty(page);
4723         unlock_extent_cached(io_tree, block_start, block_end, &cached_state,
4724                              GFP_NOFS);
4725
4726 out_unlock:
4727         if (ret)
4728                 btrfs_delalloc_release_space(inode, block_start,
4729                                              blocksize);
4730         unlock_page(page);
4731         put_page(page);
4732 out:
4733         return ret;
4734 }
4735
4736 static int maybe_insert_hole(struct btrfs_root *root, struct inode *inode,
4737                              u64 offset, u64 len)
4738 {
4739         struct btrfs_trans_handle *trans;
4740         int ret;
4741
4742         /*
4743          * Still need to make sure the inode looks like it's been updated so
4744          * that any holes get logged if we fsync.
4745          */
4746         if (btrfs_fs_incompat(root->fs_info, NO_HOLES)) {
4747                 BTRFS_I(inode)->last_trans = root->fs_info->generation;
4748                 BTRFS_I(inode)->last_sub_trans = root->log_transid;
4749                 BTRFS_I(inode)->last_log_commit = root->last_log_commit;
4750                 return 0;
4751         }
4752
4753         /*
4754          * 1 - for the one we're dropping
4755          * 1 - for the one we're adding
4756          * 1 - for updating the inode.
4757          */
4758         trans = btrfs_start_transaction(root, 3);
4759         if (IS_ERR(trans))
4760                 return PTR_ERR(trans);
4761
4762         ret = btrfs_drop_extents(trans, root, inode, offset, offset + len, 1);
4763         if (ret) {
4764                 btrfs_abort_transaction(trans, root, ret);
4765                 btrfs_end_transaction(trans, root);
4766                 return ret;
4767         }
4768
4769         ret = btrfs_insert_file_extent(trans, root, btrfs_ino(inode), offset,
4770                                        0, 0, len, 0, len, 0, 0, 0);
4771         if (ret)
4772                 btrfs_abort_transaction(trans, root, ret);
4773         else
4774                 btrfs_update_inode(trans, root, inode);
4775         btrfs_end_transaction(trans, root);
4776         return ret;
4777 }
4778
4779 /*
4780  * This function puts in dummy file extents for the area we're creating a hole
4781  * for.  So if we are truncating this file to a larger size we need to insert
4782  * these file extents so that btrfs_get_extent will return a EXTENT_MAP_HOLE for
4783  * the range between oldsize and size
4784  */
4785 int btrfs_cont_expand(struct inode *inode, loff_t oldsize, loff_t size)
4786 {
4787         struct btrfs_root *root = BTRFS_I(inode)->root;
4788         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
4789         struct extent_map *em = NULL;
4790         struct extent_state *cached_state = NULL;
4791         struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
4792         u64 hole_start = ALIGN(oldsize, root->sectorsize);
4793         u64 block_end = ALIGN(size, root->sectorsize);
4794         u64 last_byte;
4795         u64 cur_offset;
4796         u64 hole_size;
4797         int err = 0;
4798
4799         /*
4800          * If our size started in the middle of a block we need to zero out the
4801          * rest of the block before we expand the i_size, otherwise we could
4802          * expose stale data.
4803          */
4804         err = btrfs_truncate_block(inode, oldsize, 0, 0);
4805         if (err)
4806                 return err;
4807
4808         if (size <= hole_start)
4809                 return 0;
4810
4811         while (1) {
4812                 struct btrfs_ordered_extent *ordered;
4813
4814                 lock_extent_bits(io_tree, hole_start, block_end - 1,
4815                                  &cached_state);
4816                 ordered = btrfs_lookup_ordered_range(inode, hole_start,
4817                                                      block_end - hole_start);
4818                 if (!ordered)
4819                         break;
4820                 unlock_extent_cached(io_tree, hole_start, block_end - 1,
4821                                      &cached_state, GFP_NOFS);
4822                 btrfs_start_ordered_extent(inode, ordered, 1);
4823                 btrfs_put_ordered_extent(ordered);
4824         }
4825
4826         cur_offset = hole_start;
4827         while (1) {
4828                 em = btrfs_get_extent(inode, NULL, 0, cur_offset,
4829                                 block_end - cur_offset, 0);
4830                 if (IS_ERR(em)) {
4831                         err = PTR_ERR(em);
4832                         em = NULL;
4833                         break;
4834                 }
4835                 last_byte = min(extent_map_end(em), block_end);
4836                 last_byte = ALIGN(last_byte , root->sectorsize);
4837                 if (!test_bit(EXTENT_FLAG_PREALLOC, &em->flags)) {
4838                         struct extent_map *hole_em;
4839                         hole_size = last_byte - cur_offset;
4840
4841                         err = maybe_insert_hole(root, inode, cur_offset,
4842                                                 hole_size);
4843                         if (err)
4844                                 break;
4845                         btrfs_drop_extent_cache(inode, cur_offset,
4846                                                 cur_offset + hole_size - 1, 0);
4847                         hole_em = alloc_extent_map();
4848                         if (!hole_em) {
4849                                 set_bit(BTRFS_INODE_NEEDS_FULL_SYNC,
4850                                         &BTRFS_I(inode)->runtime_flags);
4851                                 goto next;
4852                         }
4853                         hole_em->start = cur_offset;
4854                         hole_em->len = hole_size;
4855                         hole_em->orig_start = cur_offset;
4856
4857                         hole_em->block_start = EXTENT_MAP_HOLE;
4858                         hole_em->block_len = 0;
4859                         hole_em->orig_block_len = 0;
4860                         hole_em->ram_bytes = hole_size;
4861                         hole_em->bdev = root->fs_info->fs_devices->latest_bdev;
4862                         hole_em->compress_type = BTRFS_COMPRESS_NONE;
4863                         hole_em->generation = root->fs_info->generation;
4864
4865                         while (1) {
4866                                 write_lock(&em_tree->lock);
4867                                 err = add_extent_mapping(em_tree, hole_em, 1);
4868                                 write_unlock(&em_tree->lock);
4869                                 if (err != -EEXIST)
4870                                         break;
4871                                 btrfs_drop_extent_cache(inode, cur_offset,
4872                                                         cur_offset +
4873                                                         hole_size - 1, 0);
4874                         }
4875                         free_extent_map(hole_em);
4876                 }
4877 next:
4878                 free_extent_map(em);
4879                 em = NULL;
4880                 cur_offset = last_byte;
4881                 if (cur_offset >= block_end)
4882                         break;
4883         }
4884         free_extent_map(em);
4885         unlock_extent_cached(io_tree, hole_start, block_end - 1, &cached_state,
4886                              GFP_NOFS);
4887         return err;
4888 }
4889
4890 static int btrfs_setsize(struct inode *inode, struct iattr *attr)
4891 {
4892         struct btrfs_root *root = BTRFS_I(inode)->root;
4893         struct btrfs_trans_handle *trans;
4894         loff_t oldsize = i_size_read(inode);
4895         loff_t newsize = attr->ia_size;
4896         int mask = attr->ia_valid;
4897         int ret;
4898
4899         /*
4900          * The regular truncate() case without ATTR_CTIME and ATTR_MTIME is a
4901          * special case where we need to update the times despite not having
4902          * these flags set.  For all other operations the VFS set these flags
4903          * explicitly if it wants a timestamp update.
4904          */
4905         if (newsize != oldsize) {
4906                 inode_inc_iversion(inode);
4907                 if (!(mask & (ATTR_CTIME | ATTR_MTIME)))
4908                         inode->i_ctime = inode->i_mtime =
4909                                 current_fs_time(inode->i_sb);
4910         }
4911
4912         if (newsize > oldsize) {
4913                 /*
4914                  * Don't do an expanding truncate while snapshoting is ongoing.
4915                  * This is to ensure the snapshot captures a fully consistent
4916                  * state of this file - if the snapshot captures this expanding
4917                  * truncation, it must capture all writes that happened before
4918                  * this truncation.
4919                  */
4920                 btrfs_wait_for_snapshot_creation(root);
4921                 ret = btrfs_cont_expand(inode, oldsize, newsize);
4922                 if (ret) {
4923                         btrfs_end_write_no_snapshoting(root);
4924                         return ret;
4925                 }
4926
4927                 trans = btrfs_start_transaction(root, 1);
4928                 if (IS_ERR(trans)) {
4929                         btrfs_end_write_no_snapshoting(root);
4930                         return PTR_ERR(trans);
4931                 }
4932
4933                 i_size_write(inode, newsize);
4934                 btrfs_ordered_update_i_size(inode, i_size_read(inode), NULL);
4935                 pagecache_isize_extended(inode, oldsize, newsize);
4936                 ret = btrfs_update_inode(trans, root, inode);
4937                 btrfs_end_write_no_snapshoting(root);
4938                 btrfs_end_transaction(trans, root);
4939         } else {
4940
4941                 /*
4942                  * We're truncating a file that used to have good data down to
4943                  * zero. Make sure it gets into the ordered flush list so that
4944                  * any new writes get down to disk quickly.
4945                  */
4946                 if (newsize == 0)
4947                         set_bit(BTRFS_INODE_ORDERED_DATA_CLOSE,
4948                                 &BTRFS_I(inode)->runtime_flags);
4949
4950                 /*
4951                  * 1 for the orphan item we're going to add
4952                  * 1 for the orphan item deletion.
4953                  */
4954                 trans = btrfs_start_transaction(root, 2);
4955                 if (IS_ERR(trans))
4956                         return PTR_ERR(trans);
4957
4958                 /*
4959                  * We need to do this in case we fail at _any_ point during the
4960                  * actual truncate.  Once we do the truncate_setsize we could
4961                  * invalidate pages which forces any outstanding ordered io to
4962                  * be instantly completed which will give us extents that need
4963                  * to be truncated.  If we fail to get an orphan inode down we
4964                  * could have left over extents that were never meant to live,
4965                  * so we need to garuntee from this point on that everything
4966                  * will be consistent.
4967                  */
4968                 ret = btrfs_orphan_add(trans, inode);
4969                 btrfs_end_transaction(trans, root);
4970                 if (ret)
4971                         return ret;
4972
4973                 /* we don't support swapfiles, so vmtruncate shouldn't fail */
4974                 truncate_setsize(inode, newsize);
4975
4976                 /* Disable nonlocked read DIO to avoid the end less truncate */
4977                 btrfs_inode_block_unlocked_dio(inode);
4978                 inode_dio_wait(inode);
4979                 btrfs_inode_resume_unlocked_dio(inode);
4980
4981                 ret = btrfs_truncate(inode);
4982                 if (ret && inode->i_nlink) {
4983                         int err;
4984
4985                         /*
4986                          * failed to truncate, disk_i_size is only adjusted down
4987                          * as we remove extents, so it should represent the true
4988                          * size of the inode, so reset the in memory size and
4989                          * delete our orphan entry.
4990                          */
4991                         trans = btrfs_join_transaction(root);
4992                         if (IS_ERR(trans)) {
4993                                 btrfs_orphan_del(NULL, inode);
4994                                 return ret;
4995                         }
4996                         i_size_write(inode, BTRFS_I(inode)->disk_i_size);
4997                         err = btrfs_orphan_del(trans, inode);
4998                         if (err)
4999                                 btrfs_abort_transaction(trans, root, err);
5000                         btrfs_end_transaction(trans, root);
5001                 }
5002         }
5003
5004         return ret;
5005 }
5006
5007 static int btrfs_setattr(struct dentry *dentry, struct iattr *attr)
5008 {
5009         struct inode *inode = d_inode(dentry);
5010         struct btrfs_root *root = BTRFS_I(inode)->root;
5011         int err;
5012
5013         if (btrfs_root_readonly(root))
5014                 return -EROFS;
5015
5016         err = inode_change_ok(inode, attr);
5017         if (err)
5018                 return err;
5019
5020         if (S_ISREG(inode->i_mode) && (attr->ia_valid & ATTR_SIZE)) {
5021                 err = btrfs_setsize(inode, attr);
5022                 if (err)
5023                         return err;
5024         }
5025
5026         if (attr->ia_valid) {
5027                 setattr_copy(inode, attr);
5028                 inode_inc_iversion(inode);
5029                 err = btrfs_dirty_inode(inode);
5030
5031                 if (!err && attr->ia_valid & ATTR_MODE)
5032                         err = posix_acl_chmod(inode, inode->i_mode);
5033         }
5034
5035         return err;
5036 }
5037
5038 /*
5039  * While truncating the inode pages during eviction, we get the VFS calling
5040  * btrfs_invalidatepage() against each page of the inode. This is slow because
5041  * the calls to btrfs_invalidatepage() result in a huge amount of calls to
5042  * lock_extent_bits() and clear_extent_bit(), which keep merging and splitting
5043  * extent_state structures over and over, wasting lots of time.
5044  *
5045  * Therefore if the inode is being evicted, let btrfs_invalidatepage() skip all
5046  * those expensive operations on a per page basis and do only the ordered io
5047  * finishing, while we release here the extent_map and extent_state structures,
5048  * without the excessive merging and splitting.
5049  */
5050 static void evict_inode_truncate_pages(struct inode *inode)
5051 {
5052         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
5053         struct extent_map_tree *map_tree = &BTRFS_I(inode)->extent_tree;
5054         struct rb_node *node;
5055
5056         ASSERT(inode->i_state & I_FREEING);
5057         truncate_inode_pages_final(&inode->i_data);
5058
5059         write_lock(&map_tree->lock);
5060         while (!RB_EMPTY_ROOT(&map_tree->map)) {
5061                 struct extent_map *em;
5062
5063                 node = rb_first(&map_tree->map);
5064                 em = rb_entry(node, struct extent_map, rb_node);
5065                 clear_bit(EXTENT_FLAG_PINNED, &em->flags);
5066                 clear_bit(EXTENT_FLAG_LOGGING, &em->flags);
5067                 remove_extent_mapping(map_tree, em);
5068                 free_extent_map(em);
5069                 if (need_resched()) {
5070                         write_unlock(&map_tree->lock);
5071                         cond_resched();
5072                         write_lock(&map_tree->lock);
5073                 }
5074         }
5075         write_unlock(&map_tree->lock);
5076
5077         /*
5078          * Keep looping until we have no more ranges in the io tree.
5079          * We can have ongoing bios started by readpages (called from readahead)
5080          * that have their endio callback (extent_io.c:end_bio_extent_readpage)
5081          * still in progress (unlocked the pages in the bio but did not yet
5082          * unlocked the ranges in the io tree). Therefore this means some
5083          * ranges can still be locked and eviction started because before
5084          * submitting those bios, which are executed by a separate task (work
5085          * queue kthread), inode references (inode->i_count) were not taken
5086          * (which would be dropped in the end io callback of each bio).
5087          * Therefore here we effectively end up waiting for those bios and
5088          * anyone else holding locked ranges without having bumped the inode's
5089          * reference count - if we don't do it, when they access the inode's
5090          * io_tree to unlock a range it may be too late, leading to an
5091          * use-after-free issue.
5092          */
5093         spin_lock(&io_tree->lock);
5094         while (!RB_EMPTY_ROOT(&io_tree->state)) {
5095                 struct extent_state *state;
5096                 struct extent_state *cached_state = NULL;
5097                 u64 start;
5098                 u64 end;
5099
5100                 node = rb_first(&io_tree->state);
5101                 state = rb_entry(node, struct extent_state, rb_node);
5102                 start = state->start;
5103                 end = state->end;
5104                 spin_unlock(&io_tree->lock);
5105
5106                 lock_extent_bits(io_tree, start, end, &cached_state);
5107
5108                 /*
5109                  * If still has DELALLOC flag, the extent didn't reach disk,
5110                  * and its reserved space won't be freed by delayed_ref.
5111                  * So we need to free its reserved space here.
5112                  * (Refer to comment in btrfs_invalidatepage, case 2)
5113                  *
5114                  * Note, end is the bytenr of last byte, so we need + 1 here.
5115                  */
5116                 if (state->state & EXTENT_DELALLOC)
5117                         btrfs_qgroup_free_data(inode, start, end - start + 1);
5118
5119                 clear_extent_bit(io_tree, start, end,
5120                                  EXTENT_LOCKED | EXTENT_DIRTY |
5121                                  EXTENT_DELALLOC | EXTENT_DO_ACCOUNTING |
5122                                  EXTENT_DEFRAG, 1, 1,
5123                                  &cached_state, GFP_NOFS);
5124
5125                 cond_resched();
5126                 spin_lock(&io_tree->lock);
5127         }
5128         spin_unlock(&io_tree->lock);
5129 }
5130
5131 void btrfs_evict_inode(struct inode *inode)
5132 {
5133         struct btrfs_trans_handle *trans;
5134         struct btrfs_root *root = BTRFS_I(inode)->root;
5135         struct btrfs_block_rsv *rsv, *global_rsv;
5136         int steal_from_global = 0;
5137         u64 min_size = btrfs_calc_trunc_metadata_size(root, 1);
5138         int ret;
5139
5140         trace_btrfs_inode_evict(inode);
5141
5142         evict_inode_truncate_pages(inode);
5143
5144         if (inode->i_nlink &&
5145             ((btrfs_root_refs(&root->root_item) != 0 &&
5146               root->root_key.objectid != BTRFS_ROOT_TREE_OBJECTID) ||
5147              btrfs_is_free_space_inode(inode)))
5148                 goto no_delete;
5149
5150         if (is_bad_inode(inode)) {
5151                 btrfs_orphan_del(NULL, inode);
5152                 goto no_delete;
5153         }
5154         /* do we really want it for ->i_nlink > 0 and zero btrfs_root_refs? */
5155         if (!special_file(inode->i_mode))
5156                 btrfs_wait_ordered_range(inode, 0, (u64)-1);
5157
5158         btrfs_free_io_failure_record(inode, 0, (u64)-1);
5159
5160         if (root->fs_info->log_root_recovering) {
5161                 BUG_ON(test_bit(BTRFS_INODE_HAS_ORPHAN_ITEM,
5162                                  &BTRFS_I(inode)->runtime_flags));
5163                 goto no_delete;
5164         }
5165
5166         if (inode->i_nlink > 0) {
5167                 BUG_ON(btrfs_root_refs(&root->root_item) != 0 &&
5168                        root->root_key.objectid != BTRFS_ROOT_TREE_OBJECTID);
5169                 goto no_delete;
5170         }
5171
5172         ret = btrfs_commit_inode_delayed_inode(inode);
5173         if (ret) {
5174                 btrfs_orphan_del(NULL, inode);
5175                 goto no_delete;
5176         }
5177
5178         rsv = btrfs_alloc_block_rsv(root, BTRFS_BLOCK_RSV_TEMP);
5179         if (!rsv) {
5180                 btrfs_orphan_del(NULL, inode);
5181                 goto no_delete;
5182         }
5183         rsv->size = min_size;
5184         rsv->failfast = 1;
5185         global_rsv = &root->fs_info->global_block_rsv;
5186
5187         btrfs_i_size_write(inode, 0);
5188
5189         /*
5190          * This is a bit simpler than btrfs_truncate since we've already
5191          * reserved our space for our orphan item in the unlink, so we just
5192          * need to reserve some slack space in case we add bytes and update
5193          * inode item when doing the truncate.
5194          */
5195         while (1) {
5196                 ret = btrfs_block_rsv_refill(root, rsv, min_size,
5197                                              BTRFS_RESERVE_FLUSH_LIMIT);
5198
5199                 /*
5200                  * Try and steal from the global reserve since we will
5201                  * likely not use this space anyway, we want to try as
5202                  * hard as possible to get this to work.
5203                  */
5204                 if (ret)
5205                         steal_from_global++;
5206                 else
5207                         steal_from_global = 0;
5208                 ret = 0;
5209
5210                 /*
5211                  * steal_from_global == 0: we reserved stuff, hooray!
5212                  * steal_from_global == 1: we didn't reserve stuff, boo!
5213                  * steal_from_global == 2: we've committed, still not a lot of
5214                  * room but maybe we'll have room in the global reserve this
5215                  * time.
5216                  * steal_from_global == 3: abandon all hope!
5217                  */
5218                 if (steal_from_global > 2) {
5219                         btrfs_warn(root->fs_info,
5220                                 "Could not get space for a delete, will truncate on mount %d",
5221                                 ret);
5222                         btrfs_orphan_del(NULL, inode);
5223                         btrfs_free_block_rsv(root, rsv);
5224                         goto no_delete;
5225                 }
5226
5227                 trans = btrfs_join_transaction(root);
5228                 if (IS_ERR(trans)) {
5229                         btrfs_orphan_del(NULL, inode);
5230                         btrfs_free_block_rsv(root, rsv);
5231                         goto no_delete;
5232                 }
5233
5234                 /*
5235                  * We can't just steal from the global reserve, we need tomake
5236                  * sure there is room to do it, if not we need to commit and try
5237                  * again.
5238                  */
5239                 if (steal_from_global) {
5240                         if (!btrfs_check_space_for_delayed_refs(trans, root))
5241                                 ret = btrfs_block_rsv_migrate(global_rsv, rsv,
5242                                                               min_size);
5243                         else
5244                                 ret = -ENOSPC;
5245                 }
5246
5247                 /*
5248                  * Couldn't steal from the global reserve, we have too much
5249                  * pending stuff built up, commit the transaction and try it
5250                  * again.
5251                  */
5252                 if (ret) {
5253                         ret = btrfs_commit_transaction(trans, root);
5254                         if (ret) {
5255                                 btrfs_orphan_del(NULL, inode);
5256                                 btrfs_free_block_rsv(root, rsv);
5257                                 goto no_delete;
5258                         }
5259                         continue;
5260                 } else {
5261                         steal_from_global = 0;
5262                 }
5263
5264                 trans->block_rsv = rsv;
5265
5266                 ret = btrfs_truncate_inode_items(trans, root, inode, 0, 0);
5267                 if (ret != -ENOSPC && ret != -EAGAIN)
5268                         break;
5269
5270                 trans->block_rsv = &root->fs_info->trans_block_rsv;
5271                 btrfs_end_transaction(trans, root);
5272                 trans = NULL;
5273                 btrfs_btree_balance_dirty(root);
5274         }
5275
5276         btrfs_free_block_rsv(root, rsv);
5277
5278         /*
5279          * Errors here aren't a big deal, it just means we leave orphan items
5280          * in the tree.  They will be cleaned up on the next mount.
5281          */
5282         if (ret == 0) {
5283                 trans->block_rsv = root->orphan_block_rsv;
5284                 btrfs_orphan_del(trans, inode);
5285         } else {
5286                 btrfs_orphan_del(NULL, inode);
5287         }
5288
5289         trans->block_rsv = &root->fs_info->trans_block_rsv;
5290         if (!(root == root->fs_info->tree_root ||
5291               root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID))
5292                 btrfs_return_ino(root, btrfs_ino(inode));
5293
5294         btrfs_end_transaction(trans, root);
5295         btrfs_btree_balance_dirty(root);
5296 no_delete:
5297         btrfs_remove_delayed_node(inode);
5298         clear_inode(inode);
5299 }
5300
5301 /*
5302  * this returns the key found in the dir entry in the location pointer.
5303  * If no dir entries were found, location->objectid is 0.
5304  */
5305 static int btrfs_inode_by_name(struct inode *dir, struct dentry *dentry,
5306                                struct btrfs_key *location)
5307 {
5308         const char *name = dentry->d_name.name;
5309         int namelen = dentry->d_name.len;
5310         struct btrfs_dir_item *di;
5311         struct btrfs_path *path;
5312         struct btrfs_root *root = BTRFS_I(dir)->root;
5313         int ret = 0;
5314
5315         path = btrfs_alloc_path();
5316         if (!path)
5317                 return -ENOMEM;
5318
5319         di = btrfs_lookup_dir_item(NULL, root, path, btrfs_ino(dir), name,
5320                                     namelen, 0);
5321         if (IS_ERR(di))
5322                 ret = PTR_ERR(di);
5323
5324         if (IS_ERR_OR_NULL(di))
5325                 goto out_err;
5326
5327         btrfs_dir_item_key_to_cpu(path->nodes[0], di, location);
5328 out:
5329         btrfs_free_path(path);
5330         return ret;
5331 out_err:
5332         location->objectid = 0;
5333         goto out;
5334 }
5335
5336 /*
5337  * when we hit a tree root in a directory, the btrfs part of the inode
5338  * needs to be changed to reflect the root directory of the tree root.  This
5339  * is kind of like crossing a mount point.
5340  */
5341 static int fixup_tree_root_location(struct btrfs_root *root,
5342                                     struct inode *dir,
5343                                     struct dentry *dentry,
5344                                     struct btrfs_key *location,
5345                                     struct btrfs_root **sub_root)
5346 {
5347         struct btrfs_path *path;
5348         struct btrfs_root *new_root;
5349         struct btrfs_root_ref *ref;
5350         struct extent_buffer *leaf;
5351         struct btrfs_key key;
5352         int ret;
5353         int err = 0;
5354
5355         path = btrfs_alloc_path();
5356         if (!path) {
5357                 err = -ENOMEM;
5358                 goto out;
5359         }
5360
5361         err = -ENOENT;
5362         key.objectid = BTRFS_I(dir)->root->root_key.objectid;
5363         key.type = BTRFS_ROOT_REF_KEY;
5364         key.offset = location->objectid;
5365
5366         ret = btrfs_search_slot(NULL, root->fs_info->tree_root, &key, path,
5367                                 0, 0);
5368         if (ret) {
5369                 if (ret < 0)
5370                         err = ret;
5371                 goto out;
5372         }
5373
5374         leaf = path->nodes[0];
5375         ref = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_root_ref);
5376         if (btrfs_root_ref_dirid(leaf, ref) != btrfs_ino(dir) ||
5377             btrfs_root_ref_name_len(leaf, ref) != dentry->d_name.len)
5378                 goto out;
5379
5380         ret = memcmp_extent_buffer(leaf, dentry->d_name.name,
5381                                    (unsigned long)(ref + 1),
5382                                    dentry->d_name.len);
5383         if (ret)
5384                 goto out;
5385
5386         btrfs_release_path(path);
5387
5388         new_root = btrfs_read_fs_root_no_name(root->fs_info, location);
5389         if (IS_ERR(new_root)) {
5390                 err = PTR_ERR(new_root);
5391                 goto out;
5392         }
5393
5394         *sub_root = new_root;
5395         location->objectid = btrfs_root_dirid(&new_root->root_item);
5396         location->type = BTRFS_INODE_ITEM_KEY;
5397         location->offset = 0;
5398         err = 0;
5399 out:
5400         btrfs_free_path(path);
5401         return err;
5402 }
5403
5404 static void inode_tree_add(struct inode *inode)
5405 {
5406         struct btrfs_root *root = BTRFS_I(inode)->root;
5407         struct btrfs_inode *entry;
5408         struct rb_node **p;
5409         struct rb_node *parent;
5410         struct rb_node *new = &BTRFS_I(inode)->rb_node;
5411         u64 ino = btrfs_ino(inode);
5412
5413         if (inode_unhashed(inode))
5414                 return;
5415         parent = NULL;
5416         spin_lock(&root->inode_lock);
5417         p = &root->inode_tree.rb_node;
5418         while (*p) {
5419                 parent = *p;
5420                 entry = rb_entry(parent, struct btrfs_inode, rb_node);
5421
5422                 if (ino < btrfs_ino(&entry->vfs_inode))
5423                         p = &parent->rb_left;
5424                 else if (ino > btrfs_ino(&entry->vfs_inode))
5425                         p = &parent->rb_right;
5426                 else {
5427                         WARN_ON(!(entry->vfs_inode.i_state &
5428                                   (I_WILL_FREE | I_FREEING)));
5429                         rb_replace_node(parent, new, &root->inode_tree);
5430                         RB_CLEAR_NODE(parent);
5431                         spin_unlock(&root->inode_lock);
5432                         return;
5433                 }
5434         }
5435         rb_link_node(new, parent, p);
5436         rb_insert_color(new, &root->inode_tree);
5437         spin_unlock(&root->inode_lock);
5438 }
5439
5440 static void inode_tree_del(struct inode *inode)
5441 {
5442         struct btrfs_root *root = BTRFS_I(inode)->root;
5443         int empty = 0;
5444
5445         spin_lock(&root->inode_lock);
5446         if (!RB_EMPTY_NODE(&BTRFS_I(inode)->rb_node)) {
5447                 rb_erase(&BTRFS_I(inode)->rb_node, &root->inode_tree);
5448                 RB_CLEAR_NODE(&BTRFS_I(inode)->rb_node);
5449                 empty = RB_EMPTY_ROOT(&root->inode_tree);
5450         }
5451         spin_unlock(&root->inode_lock);
5452
5453         if (empty && btrfs_root_refs(&root->root_item) == 0) {
5454                 synchronize_srcu(&root->fs_info->subvol_srcu);
5455                 spin_lock(&root->inode_lock);
5456                 empty = RB_EMPTY_ROOT(&root->inode_tree);
5457                 spin_unlock(&root->inode_lock);
5458                 if (empty)
5459                         btrfs_add_dead_root(root);
5460         }
5461 }
5462
5463 void btrfs_invalidate_inodes(struct btrfs_root *root)
5464 {
5465         struct rb_node *node;
5466         struct rb_node *prev;
5467         struct btrfs_inode *entry;
5468         struct inode *inode;
5469         u64 objectid = 0;
5470
5471         if (!test_bit(BTRFS_FS_STATE_ERROR, &root->fs_info->fs_state))
5472                 WARN_ON(btrfs_root_refs(&root->root_item) != 0);
5473
5474         spin_lock(&root->inode_lock);
5475 again:
5476         node = root->inode_tree.rb_node;
5477         prev = NULL;
5478         while (node) {
5479                 prev = node;
5480                 entry = rb_entry(node, struct btrfs_inode, rb_node);
5481
5482                 if (objectid < btrfs_ino(&entry->vfs_inode))
5483                         node = node->rb_left;
5484                 else if (objectid > btrfs_ino(&entry->vfs_inode))
5485                         node = node->rb_right;
5486                 else
5487                         break;
5488         }
5489         if (!node) {
5490                 while (prev) {
5491                         entry = rb_entry(prev, struct btrfs_inode, rb_node);
5492                         if (objectid <= btrfs_ino(&entry->vfs_inode)) {
5493                                 node = prev;
5494                                 break;
5495                         }
5496                         prev = rb_next(prev);
5497                 }
5498         }
5499         while (node) {
5500                 entry = rb_entry(node, struct btrfs_inode, rb_node);
5501                 objectid = btrfs_ino(&entry->vfs_inode) + 1;
5502                 inode = igrab(&entry->vfs_inode);
5503                 if (inode) {
5504                         spin_unlock(&root->inode_lock);
5505                         if (atomic_read(&inode->i_count) > 1)
5506                                 d_prune_aliases(inode);
5507                         /*
5508                          * btrfs_drop_inode will have it removed from
5509                          * the inode cache when its usage count
5510                          * hits zero.
5511                          */
5512                         iput(inode);
5513                         cond_resched();
5514                         spin_lock(&root->inode_lock);
5515                         goto again;
5516                 }
5517
5518                 if (cond_resched_lock(&root->inode_lock))
5519                         goto again;
5520
5521                 node = rb_next(node);
5522         }
5523         spin_unlock(&root->inode_lock);
5524 }
5525
5526 static int btrfs_init_locked_inode(struct inode *inode, void *p)
5527 {
5528         struct btrfs_iget_args *args = p;
5529         inode->i_ino = args->location->objectid;
5530         memcpy(&BTRFS_I(inode)->location, args->location,
5531                sizeof(*args->location));
5532         BTRFS_I(inode)->root = args->root;
5533         return 0;
5534 }
5535
5536 static int btrfs_find_actor(struct inode *inode, void *opaque)
5537 {
5538         struct btrfs_iget_args *args = opaque;
5539         return args->location->objectid == BTRFS_I(inode)->location.objectid &&
5540                 args->root == BTRFS_I(inode)->root;
5541 }
5542
5543 static struct inode *btrfs_iget_locked(struct super_block *s,
5544                                        struct btrfs_key *location,
5545                                        struct btrfs_root *root)
5546 {
5547         struct inode *inode;
5548         struct btrfs_iget_args args;
5549         unsigned long hashval = btrfs_inode_hash(location->objectid, root);
5550
5551         args.location = location;
5552         args.root = root;
5553
5554         inode = iget5_locked(s, hashval, btrfs_find_actor,
5555                              btrfs_init_locked_inode,
5556                              (void *)&args);
5557         return inode;
5558 }
5559
5560 /* Get an inode object given its location and corresponding root.
5561  * Returns in *is_new if the inode was read from disk
5562  */
5563 struct inode *btrfs_iget(struct super_block *s, struct btrfs_key *location,
5564                          struct btrfs_root *root, int *new)
5565 {
5566         struct inode *inode;
5567
5568         inode = btrfs_iget_locked(s, location, root);
5569         if (!inode)
5570                 return ERR_PTR(-ENOMEM);
5571
5572         if (inode->i_state & I_NEW) {
5573                 btrfs_read_locked_inode(inode);
5574                 if (!is_bad_inode(inode)) {
5575                         inode_tree_add(inode);
5576                         unlock_new_inode(inode);
5577                         if (new)
5578                                 *new = 1;
5579                 } else {
5580                         unlock_new_inode(inode);
5581                         iput(inode);
5582                         inode = ERR_PTR(-ESTALE);
5583                 }
5584         }
5585
5586         return inode;
5587 }
5588
5589 static struct inode *new_simple_dir(struct super_block *s,
5590                                     struct btrfs_key *key,
5591                                     struct btrfs_root *root)
5592 {
5593         struct inode *inode = new_inode(s);
5594
5595         if (!inode)
5596                 return ERR_PTR(-ENOMEM);
5597
5598         BTRFS_I(inode)->root = root;
5599         memcpy(&BTRFS_I(inode)->location, key, sizeof(*key));
5600         set_bit(BTRFS_INODE_DUMMY, &BTRFS_I(inode)->runtime_flags);
5601
5602         inode->i_ino = BTRFS_EMPTY_SUBVOL_DIR_OBJECTID;
5603         inode->i_op = &btrfs_dir_ro_inode_operations;
5604         inode->i_fop = &simple_dir_operations;
5605         inode->i_mode = S_IFDIR | S_IRUGO | S_IWUSR | S_IXUGO;
5606         inode->i_mtime = current_fs_time(inode->i_sb);
5607         inode->i_atime = inode->i_mtime;
5608         inode->i_ctime = inode->i_mtime;
5609         BTRFS_I(inode)->i_otime = inode->i_mtime;
5610
5611         return inode;
5612 }
5613
5614 struct inode *btrfs_lookup_dentry(struct inode *dir, struct dentry *dentry)
5615 {
5616         struct inode *inode;
5617         struct btrfs_root *root = BTRFS_I(dir)->root;
5618         struct btrfs_root *sub_root = root;
5619         struct btrfs_key location;
5620         int index;
5621         int ret = 0;
5622
5623         if (dentry->d_name.len > BTRFS_NAME_LEN)
5624                 return ERR_PTR(-ENAMETOOLONG);
5625
5626         ret = btrfs_inode_by_name(dir, dentry, &location);
5627         if (ret < 0)
5628                 return ERR_PTR(ret);
5629
5630         if (location.objectid == 0)
5631                 return ERR_PTR(-ENOENT);
5632
5633         if (location.type == BTRFS_INODE_ITEM_KEY) {
5634                 inode = btrfs_iget(dir->i_sb, &location, root, NULL);
5635                 return inode;
5636         }
5637
5638         BUG_ON(location.type != BTRFS_ROOT_ITEM_KEY);
5639
5640         index = srcu_read_lock(&root->fs_info->subvol_srcu);
5641         ret = fixup_tree_root_location(root, dir, dentry,
5642                                        &location, &sub_root);
5643         if (ret < 0) {
5644                 if (ret != -ENOENT)
5645                         inode = ERR_PTR(ret);
5646                 else
5647                         inode = new_simple_dir(dir->i_sb, &location, sub_root);
5648         } else {
5649                 inode = btrfs_iget(dir->i_sb, &location, sub_root, NULL);
5650         }
5651         srcu_read_unlock(&root->fs_info->subvol_srcu, index);
5652
5653         if (!IS_ERR(inode) && root != sub_root) {
5654                 down_read(&root->fs_info->cleanup_work_sem);
5655                 if (!(inode->i_sb->s_flags & MS_RDONLY))
5656                         ret = btrfs_orphan_cleanup(sub_root);
5657                 up_read(&root->fs_info->cleanup_work_sem);
5658                 if (ret) {
5659                         iput(inode);
5660                         inode = ERR_PTR(ret);
5661                 }
5662         }
5663
5664         return inode;
5665 }
5666
5667 static int btrfs_dentry_delete(const struct dentry *dentry)
5668 {
5669         struct btrfs_root *root;
5670         struct inode *inode = d_inode(dentry);
5671
5672         if (!inode && !IS_ROOT(dentry))
5673                 inode = d_inode(dentry->d_parent);
5674
5675         if (inode) {
5676                 root = BTRFS_I(inode)->root;
5677                 if (btrfs_root_refs(&root->root_item) == 0)
5678                         return 1;
5679
5680                 if (btrfs_ino(inode) == BTRFS_EMPTY_SUBVOL_DIR_OBJECTID)
5681                         return 1;
5682         }
5683         return 0;
5684 }
5685
5686 static void btrfs_dentry_release(struct dentry *dentry)
5687 {
5688         kfree(dentry->d_fsdata);
5689 }
5690
5691 static struct dentry *btrfs_lookup(struct inode *dir, struct dentry *dentry,
5692                                    unsigned int flags)
5693 {
5694         struct inode *inode;
5695
5696         inode = btrfs_lookup_dentry(dir, dentry);
5697         if (IS_ERR(inode)) {
5698                 if (PTR_ERR(inode) == -ENOENT)
5699                         inode = NULL;
5700                 else
5701                         return ERR_CAST(inode);
5702         }
5703
5704         return d_splice_alias(inode, dentry);
5705 }
5706
5707 unsigned char btrfs_filetype_table[] = {
5708         DT_UNKNOWN, DT_REG, DT_DIR, DT_CHR, DT_BLK, DT_FIFO, DT_SOCK, DT_LNK
5709 };
5710
5711 static int btrfs_real_readdir(struct file *file, struct dir_context *ctx)
5712 {
5713         struct inode *inode = file_inode(file);
5714         struct btrfs_root *root = BTRFS_I(inode)->root;
5715         struct btrfs_item *item;
5716         struct btrfs_dir_item *di;
5717         struct btrfs_key key;
5718         struct btrfs_key found_key;
5719         struct btrfs_path *path;
5720         struct list_head ins_list;
5721         struct list_head del_list;
5722         int ret;
5723         struct extent_buffer *leaf;
5724         int slot;
5725         unsigned char d_type;
5726         int over = 0;
5727         u32 di_cur;
5728         u32 di_total;
5729         u32 di_len;
5730         int key_type = BTRFS_DIR_INDEX_KEY;
5731         char tmp_name[32];
5732         char *name_ptr;
5733         int name_len;
5734         int is_curr = 0;        /* ctx->pos points to the current index? */
5735         bool emitted;
5736
5737         /* FIXME, use a real flag for deciding about the key type */
5738         if (root->fs_info->tree_root == root)
5739                 key_type = BTRFS_DIR_ITEM_KEY;
5740
5741         if (!dir_emit_dots(file, ctx))
5742                 return 0;
5743
5744         path = btrfs_alloc_path();
5745         if (!path)
5746                 return -ENOMEM;
5747
5748         path->reada = READA_FORWARD;
5749
5750         if (key_type == BTRFS_DIR_INDEX_KEY) {
5751                 INIT_LIST_HEAD(&ins_list);
5752                 INIT_LIST_HEAD(&del_list);
5753                 btrfs_get_delayed_items(inode, &ins_list, &del_list);
5754         }
5755
5756         key.type = key_type;
5757         key.offset = ctx->pos;
5758         key.objectid = btrfs_ino(inode);
5759
5760         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
5761         if (ret < 0)
5762                 goto err;
5763
5764         emitted = false;
5765         while (1) {
5766                 leaf = path->nodes[0];
5767                 slot = path->slots[0];
5768                 if (slot >= btrfs_header_nritems(leaf)) {
5769                         ret = btrfs_next_leaf(root, path);
5770                         if (ret < 0)
5771                                 goto err;
5772                         else if (ret > 0)
5773                                 break;
5774                         continue;
5775                 }
5776
5777                 item = btrfs_item_nr(slot);
5778                 btrfs_item_key_to_cpu(leaf, &found_key, slot);
5779
5780                 if (found_key.objectid != key.objectid)
5781                         break;
5782                 if (found_key.type != key_type)
5783                         break;
5784                 if (found_key.offset < ctx->pos)
5785                         goto next;
5786                 if (key_type == BTRFS_DIR_INDEX_KEY &&
5787                     btrfs_should_delete_dir_index(&del_list,
5788                                                   found_key.offset))
5789                         goto next;
5790
5791                 ctx->pos = found_key.offset;
5792                 is_curr = 1;
5793
5794                 di = btrfs_item_ptr(leaf, slot, struct btrfs_dir_item);
5795                 di_cur = 0;
5796                 di_total = btrfs_item_size(leaf, item);
5797
5798                 while (di_cur < di_total) {
5799                         struct btrfs_key location;
5800
5801                         if (verify_dir_item(root, leaf, di))
5802                                 break;
5803
5804                         name_len = btrfs_dir_name_len(leaf, di);
5805                         if (name_len <= sizeof(tmp_name)) {
5806                                 name_ptr = tmp_name;
5807                         } else {
5808                                 name_ptr = kmalloc(name_len, GFP_KERNEL);
5809                                 if (!name_ptr) {
5810                                         ret = -ENOMEM;
5811                                         goto err;
5812                                 }
5813                         }
5814                         read_extent_buffer(leaf, name_ptr,
5815                                            (unsigned long)(di + 1), name_len);
5816
5817                         d_type = btrfs_filetype_table[btrfs_dir_type(leaf, di)];
5818                         btrfs_dir_item_key_to_cpu(leaf, di, &location);
5819
5820
5821                         /* is this a reference to our own snapshot? If so
5822                          * skip it.
5823                          *
5824                          * In contrast to old kernels, we insert the snapshot's
5825                          * dir item and dir index after it has been created, so
5826                          * we won't find a reference to our own snapshot. We
5827                          * still keep the following code for backward
5828                          * compatibility.
5829                          */
5830                         if (location.type == BTRFS_ROOT_ITEM_KEY &&
5831                             location.objectid == root->root_key.objectid) {
5832                                 over = 0;
5833                                 goto skip;
5834                         }
5835                         over = !dir_emit(ctx, name_ptr, name_len,
5836                                        location.objectid, d_type);
5837
5838 skip:
5839                         if (name_ptr != tmp_name)
5840                                 kfree(name_ptr);
5841
5842                         if (over)
5843                                 goto nopos;
5844                         emitted = true;
5845                         di_len = btrfs_dir_name_len(leaf, di) +
5846                                  btrfs_dir_data_len(leaf, di) + sizeof(*di);
5847                         di_cur += di_len;
5848                         di = (struct btrfs_dir_item *)((char *)di + di_len);
5849                 }
5850 next:
5851                 path->slots[0]++;
5852         }
5853
5854         if (key_type == BTRFS_DIR_INDEX_KEY) {
5855                 if (is_curr)
5856                         ctx->pos++;
5857                 ret = btrfs_readdir_delayed_dir_index(ctx, &ins_list, &emitted);
5858                 if (ret)
5859                         goto nopos;
5860         }
5861
5862         /*
5863          * If we haven't emitted any dir entry, we must not touch ctx->pos as
5864          * it was was set to the termination value in previous call. We assume
5865          * that "." and ".." were emitted if we reach this point and set the
5866          * termination value as well for an empty directory.
5867          */
5868         if (ctx->pos > 2 && !emitted)
5869                 goto nopos;
5870
5871         /* Reached end of directory/root. Bump pos past the last item. */
5872         ctx->pos++;
5873
5874         /*
5875          * Stop new entries from being returned after we return the last
5876          * entry.
5877          *
5878          * New directory entries are assigned a strictly increasing
5879          * offset.  This means that new entries created during readdir
5880          * are *guaranteed* to be seen in the future by that readdir.
5881          * This has broken buggy programs which operate on names as
5882          * they're returned by readdir.  Until we re-use freed offsets
5883          * we have this hack to stop new entries from being returned
5884          * under the assumption that they'll never reach this huge
5885          * offset.
5886          *
5887          * This is being careful not to overflow 32bit loff_t unless the
5888          * last entry requires it because doing so has broken 32bit apps
5889          * in the past.
5890          */
5891         if (key_type == BTRFS_DIR_INDEX_KEY) {
5892                 if (ctx->pos >= INT_MAX)
5893                         ctx->pos = LLONG_MAX;
5894                 else
5895                         ctx->pos = INT_MAX;
5896         }
5897 nopos:
5898         ret = 0;
5899 err:
5900         if (key_type == BTRFS_DIR_INDEX_KEY)
5901                 btrfs_put_delayed_items(&ins_list, &del_list);
5902         btrfs_free_path(path);
5903         return ret;
5904 }
5905
5906 int btrfs_write_inode(struct inode *inode, struct writeback_control *wbc)
5907 {
5908         struct btrfs_root *root = BTRFS_I(inode)->root;
5909         struct btrfs_trans_handle *trans;
5910         int ret = 0;
5911         bool nolock = false;
5912
5913         if (test_bit(BTRFS_INODE_DUMMY, &BTRFS_I(inode)->runtime_flags))
5914                 return 0;
5915
5916         if (btrfs_fs_closing(root->fs_info) && btrfs_is_free_space_inode(inode))
5917                 nolock = true;
5918
5919         if (wbc->sync_mode == WB_SYNC_ALL) {
5920                 if (nolock)
5921                         trans = btrfs_join_transaction_nolock(root);
5922                 else
5923                         trans = btrfs_join_transaction(root);
5924                 if (IS_ERR(trans))
5925                         return PTR_ERR(trans);
5926                 ret = btrfs_commit_transaction(trans, root);
5927         }
5928         return ret;
5929 }
5930
5931 /*
5932  * This is somewhat expensive, updating the tree every time the
5933  * inode changes.  But, it is most likely to find the inode in cache.
5934  * FIXME, needs more benchmarking...there are no reasons other than performance
5935  * to keep or drop this code.
5936  */
5937 static int btrfs_dirty_inode(struct inode *inode)
5938 {
5939         struct btrfs_root *root = BTRFS_I(inode)->root;
5940         struct btrfs_trans_handle *trans;
5941         int ret;
5942
5943         if (test_bit(BTRFS_INODE_DUMMY, &BTRFS_I(inode)->runtime_flags))
5944                 return 0;
5945
5946         trans = btrfs_join_transaction(root);
5947         if (IS_ERR(trans))
5948                 return PTR_ERR(trans);
5949
5950         ret = btrfs_update_inode(trans, root, inode);
5951         if (ret && ret == -ENOSPC) {
5952                 /* whoops, lets try again with the full transaction */
5953                 btrfs_end_transaction(trans, root);
5954                 trans = btrfs_start_transaction(root, 1);
5955                 if (IS_ERR(trans))
5956                         return PTR_ERR(trans);
5957
5958                 ret = btrfs_update_inode(trans, root, inode);
5959         }
5960         btrfs_end_transaction(trans, root);
5961         if (BTRFS_I(inode)->delayed_node)
5962                 btrfs_balance_delayed_items(root);
5963
5964         return ret;
5965 }
5966
5967 /*
5968  * This is a copy of file_update_time.  We need this so we can return error on
5969  * ENOSPC for updating the inode in the case of file write and mmap writes.
5970  */
5971 static int btrfs_update_time(struct inode *inode, struct timespec *now,
5972                              int flags)
5973 {
5974         struct btrfs_root *root = BTRFS_I(inode)->root;
5975
5976         if (btrfs_root_readonly(root))
5977                 return -EROFS;
5978
5979         if (flags & S_VERSION)
5980                 inode_inc_iversion(inode);
5981         if (flags & S_CTIME)
5982                 inode->i_ctime = *now;
5983         if (flags & S_MTIME)
5984                 inode->i_mtime = *now;
5985         if (flags & S_ATIME)
5986                 inode->i_atime = *now;
5987         return btrfs_dirty_inode(inode);
5988 }
5989
5990 /*
5991  * find the highest existing sequence number in a directory
5992  * and then set the in-memory index_cnt variable to reflect
5993  * free sequence numbers
5994  */
5995 static int btrfs_set_inode_index_count(struct inode *inode)
5996 {
5997         struct btrfs_root *root = BTRFS_I(inode)->root;
5998         struct btrfs_key key, found_key;
5999         struct btrfs_path *path;
6000         struct extent_buffer *leaf;
6001         int ret;
6002
6003         key.objectid = btrfs_ino(inode);
6004         key.type = BTRFS_DIR_INDEX_KEY;
6005         key.offset = (u64)-1;
6006
6007         path = btrfs_alloc_path();
6008         if (!path)
6009                 return -ENOMEM;
6010
6011         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
6012         if (ret < 0)
6013                 goto out;
6014         /* FIXME: we should be able to handle this */
6015         if (ret == 0)
6016                 goto out;
6017         ret = 0;
6018
6019         /*
6020          * MAGIC NUMBER EXPLANATION:
6021          * since we search a directory based on f_pos we have to start at 2
6022          * since '.' and '..' have f_pos of 0 and 1 respectively, so everybody
6023          * else has to start at 2
6024          */
6025         if (path->slots[0] == 0) {
6026                 BTRFS_I(inode)->index_cnt = 2;
6027                 goto out;
6028         }
6029
6030         path->slots[0]--;
6031
6032         leaf = path->nodes[0];
6033         btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
6034
6035         if (found_key.objectid != btrfs_ino(inode) ||
6036             found_key.type != BTRFS_DIR_INDEX_KEY) {
6037                 BTRFS_I(inode)->index_cnt = 2;
6038                 goto out;
6039         }
6040
6041         BTRFS_I(inode)->index_cnt = found_key.offset + 1;
6042 out:
6043         btrfs_free_path(path);
6044         return ret;
6045 }
6046
6047 /*
6048  * helper to find a free sequence number in a given directory.  This current
6049  * code is very simple, later versions will do smarter things in the btree
6050  */
6051 int btrfs_set_inode_index(struct inode *dir, u64 *index)
6052 {
6053         int ret = 0;
6054
6055         if (BTRFS_I(dir)->index_cnt == (u64)-1) {
6056                 ret = btrfs_inode_delayed_dir_index_count(dir);
6057                 if (ret) {
6058                         ret = btrfs_set_inode_index_count(dir);
6059                         if (ret)
6060                                 return ret;
6061                 }
6062         }
6063
6064         *index = BTRFS_I(dir)->index_cnt;
6065         BTRFS_I(dir)->index_cnt++;
6066
6067         return ret;
6068 }
6069
6070 static int btrfs_insert_inode_locked(struct inode *inode)
6071 {
6072         struct btrfs_iget_args args;
6073         args.location = &BTRFS_I(inode)->location;
6074         args.root = BTRFS_I(inode)->root;
6075
6076         return insert_inode_locked4(inode,
6077                    btrfs_inode_hash(inode->i_ino, BTRFS_I(inode)->root),
6078                    btrfs_find_actor, &args);
6079 }
6080
6081 static struct inode *btrfs_new_inode(struct btrfs_trans_handle *trans,
6082                                      struct btrfs_root *root,
6083                                      struct inode *dir,
6084                                      const char *name, int name_len,
6085                                      u64 ref_objectid, u64 objectid,
6086                                      umode_t mode, u64 *index)
6087 {
6088         struct inode *inode;
6089         struct btrfs_inode_item *inode_item;
6090         struct btrfs_key *location;
6091         struct btrfs_path *path;
6092         struct btrfs_inode_ref *ref;
6093         struct btrfs_key key[2];
6094         u32 sizes[2];
6095         int nitems = name ? 2 : 1;
6096         unsigned long ptr;
6097         int ret;
6098
6099         path = btrfs_alloc_path();
6100         if (!path)
6101                 return ERR_PTR(-ENOMEM);
6102
6103         inode = new_inode(root->fs_info->sb);
6104         if (!inode) {
6105                 btrfs_free_path(path);
6106                 return ERR_PTR(-ENOMEM);
6107         }
6108
6109         /*
6110          * O_TMPFILE, set link count to 0, so that after this point,
6111          * we fill in an inode item with the correct link count.
6112          */
6113         if (!name)
6114                 set_nlink(inode, 0);
6115
6116         /*
6117          * we have to initialize this early, so we can reclaim the inode
6118          * number if we fail afterwards in this function.
6119          */
6120         inode->i_ino = objectid;
6121
6122         if (dir && name) {
6123                 trace_btrfs_inode_request(dir);
6124
6125                 ret = btrfs_set_inode_index(dir, index);
6126                 if (ret) {
6127                         btrfs_free_path(path);
6128                         iput(inode);
6129                         return ERR_PTR(ret);
6130                 }
6131         } else if (dir) {
6132                 *index = 0;
6133         }
6134         /*
6135          * index_cnt is ignored for everything but a dir,
6136          * btrfs_get_inode_index_count has an explanation for the magic
6137          * number
6138          */
6139         BTRFS_I(inode)->index_cnt = 2;
6140         BTRFS_I(inode)->dir_index = *index;
6141         BTRFS_I(inode)->root = root;
6142         BTRFS_I(inode)->generation = trans->transid;
6143         inode->i_generation = BTRFS_I(inode)->generation;
6144
6145         /*
6146          * We could have gotten an inode number from somebody who was fsynced
6147          * and then removed in this same transaction, so let's just set full
6148          * sync since it will be a full sync anyway and this will blow away the
6149          * old info in the log.
6150          */
6151         set_bit(BTRFS_INODE_NEEDS_FULL_SYNC, &BTRFS_I(inode)->runtime_flags);
6152
6153         key[0].objectid = objectid;
6154         key[0].type = BTRFS_INODE_ITEM_KEY;
6155         key[0].offset = 0;
6156
6157         sizes[0] = sizeof(struct btrfs_inode_item);
6158
6159         if (name) {
6160                 /*
6161                  * Start new inodes with an inode_ref. This is slightly more
6162                  * efficient for small numbers of hard links since they will
6163                  * be packed into one item. Extended refs will kick in if we
6164                  * add more hard links than can fit in the ref item.
6165                  */
6166                 key[1].objectid = objectid;
6167                 key[1].type = BTRFS_INODE_REF_KEY;
6168                 key[1].offset = ref_objectid;
6169
6170                 sizes[1] = name_len + sizeof(*ref);
6171         }
6172
6173         location = &BTRFS_I(inode)->location;
6174         location->objectid = objectid;
6175         location->offset = 0;
6176         location->type = BTRFS_INODE_ITEM_KEY;
6177
6178         ret = btrfs_insert_inode_locked(inode);
6179         if (ret < 0)
6180                 goto fail;
6181
6182         path->leave_spinning = 1;
6183         ret = btrfs_insert_empty_items(trans, root, path, key, sizes, nitems);
6184         if (ret != 0)
6185                 goto fail_unlock;
6186
6187         inode_init_owner(inode, dir, mode);
6188         inode_set_bytes(inode, 0);
6189
6190         inode->i_mtime = current_fs_time(inode->i_sb);
6191         inode->i_atime = inode->i_mtime;
6192         inode->i_ctime = inode->i_mtime;
6193         BTRFS_I(inode)->i_otime = inode->i_mtime;
6194
6195         inode_item = btrfs_item_ptr(path->nodes[0], path->slots[0],
6196                                   struct btrfs_inode_item);
6197         memset_extent_buffer(path->nodes[0], 0, (unsigned long)inode_item,
6198                              sizeof(*inode_item));
6199         fill_inode_item(trans, path->nodes[0], inode_item, inode);
6200
6201         if (name) {
6202                 ref = btrfs_item_ptr(path->nodes[0], path->slots[0] + 1,
6203                                      struct btrfs_inode_ref);
6204                 btrfs_set_inode_ref_name_len(path->nodes[0], ref, name_len);
6205                 btrfs_set_inode_ref_index(path->nodes[0], ref, *index);
6206                 ptr = (unsigned long)(ref + 1);
6207                 write_extent_buffer(path->nodes[0], name, ptr, name_len);
6208         }
6209
6210         btrfs_mark_buffer_dirty(path->nodes[0]);
6211         btrfs_free_path(path);
6212
6213         btrfs_inherit_iflags(inode, dir);
6214
6215         if (S_ISREG(mode)) {
6216                 if (btrfs_test_opt(root, NODATASUM))
6217                         BTRFS_I(inode)->flags |= BTRFS_INODE_NODATASUM;
6218                 if (btrfs_test_opt(root, NODATACOW))
6219                         BTRFS_I(inode)->flags |= BTRFS_INODE_NODATACOW |
6220                                 BTRFS_INODE_NODATASUM;
6221         }
6222
6223         inode_tree_add(inode);
6224
6225         trace_btrfs_inode_new(inode);
6226         btrfs_set_inode_last_trans(trans, inode);
6227
6228         btrfs_update_root_times(trans, root);
6229
6230         ret = btrfs_inode_inherit_props(trans, inode, dir);
6231         if (ret)
6232                 btrfs_err(root->fs_info,
6233                           "error inheriting props for ino %llu (root %llu): %d",
6234                           btrfs_ino(inode), root->root_key.objectid, ret);
6235
6236         return inode;
6237
6238 fail_unlock:
6239         unlock_new_inode(inode);
6240 fail:
6241         if (dir && name)
6242                 BTRFS_I(dir)->index_cnt--;
6243         btrfs_free_path(path);
6244         iput(inode);
6245         return ERR_PTR(ret);
6246 }
6247
6248 static inline u8 btrfs_inode_type(struct inode *inode)
6249 {
6250         return btrfs_type_by_mode[(inode->i_mode & S_IFMT) >> S_SHIFT];
6251 }
6252
6253 /*
6254  * utility function to add 'inode' into 'parent_inode' with
6255  * a give name and a given sequence number.
6256  * if 'add_backref' is true, also insert a backref from the
6257  * inode to the parent directory.
6258  */
6259 int btrfs_add_link(struct btrfs_trans_handle *trans,
6260                    struct inode *parent_inode, struct inode *inode,
6261                    const char *name, int name_len, int add_backref, u64 index)
6262 {
6263         int ret = 0;
6264         struct btrfs_key key;
6265         struct btrfs_root *root = BTRFS_I(parent_inode)->root;
6266         u64 ino = btrfs_ino(inode);
6267         u64 parent_ino = btrfs_ino(parent_inode);
6268
6269         if (unlikely(ino == BTRFS_FIRST_FREE_OBJECTID)) {
6270                 memcpy(&key, &BTRFS_I(inode)->root->root_key, sizeof(key));
6271         } else {
6272                 key.objectid = ino;
6273                 key.type = BTRFS_INODE_ITEM_KEY;
6274                 key.offset = 0;
6275         }
6276
6277         if (unlikely(ino == BTRFS_FIRST_FREE_OBJECTID)) {
6278                 ret = btrfs_add_root_ref(trans, root->fs_info->tree_root,
6279                                          key.objectid, root->root_key.objectid,
6280                                          parent_ino, index, name, name_len);
6281         } else if (add_backref) {
6282                 ret = btrfs_insert_inode_ref(trans, root, name, name_len, ino,
6283                                              parent_ino, index);
6284         }
6285
6286         /* Nothing to clean up yet */
6287         if (ret)
6288                 return ret;
6289
6290         ret = btrfs_insert_dir_item(trans, root, name, name_len,
6291                                     parent_inode, &key,
6292                                     btrfs_inode_type(inode), index);
6293         if (ret == -EEXIST || ret == -EOVERFLOW)
6294                 goto fail_dir_item;
6295         else if (ret) {
6296                 btrfs_abort_transaction(trans, root, ret);
6297                 return ret;
6298         }
6299
6300         btrfs_i_size_write(parent_inode, parent_inode->i_size +
6301                            name_len * 2);
6302         inode_inc_iversion(parent_inode);
6303         parent_inode->i_mtime = parent_inode->i_ctime =
6304                 current_fs_time(parent_inode->i_sb);
6305         ret = btrfs_update_inode(trans, root, parent_inode);
6306         if (ret)
6307                 btrfs_abort_transaction(trans, root, ret);
6308         return ret;
6309
6310 fail_dir_item:
6311         if (unlikely(ino == BTRFS_FIRST_FREE_OBJECTID)) {
6312                 u64 local_index;
6313                 int err;
6314                 err = btrfs_del_root_ref(trans, root->fs_info->tree_root,
6315                                  key.objectid, root->root_key.objectid,
6316                                  parent_ino, &local_index, name, name_len);
6317
6318         } else if (add_backref) {
6319                 u64 local_index;
6320                 int err;
6321
6322                 err = btrfs_del_inode_ref(trans, root, name, name_len,
6323                                           ino, parent_ino, &local_index);
6324         }
6325         return ret;
6326 }
6327
6328 static int btrfs_add_nondir(struct btrfs_trans_handle *trans,
6329                             struct inode *dir, struct dentry *dentry,
6330                             struct inode *inode, int backref, u64 index)
6331 {
6332         int err = btrfs_add_link(trans, dir, inode,
6333                                  dentry->d_name.name, dentry->d_name.len,
6334                                  backref, index);
6335         if (err > 0)
6336                 err = -EEXIST;
6337         return err;
6338 }
6339
6340 static int btrfs_mknod(struct inode *dir, struct dentry *dentry,
6341                         umode_t mode, dev_t rdev)
6342 {
6343         struct btrfs_trans_handle *trans;
6344         struct btrfs_root *root = BTRFS_I(dir)->root;
6345         struct inode *inode = NULL;
6346         int err;
6347         int drop_inode = 0;
6348         u64 objectid;
6349         u64 index = 0;
6350
6351         /*
6352          * 2 for inode item and ref
6353          * 2 for dir items
6354          * 1 for xattr if selinux is on
6355          */
6356         trans = btrfs_start_transaction(root, 5);
6357         if (IS_ERR(trans))
6358                 return PTR_ERR(trans);
6359
6360         err = btrfs_find_free_ino(root, &objectid);
6361         if (err)
6362                 goto out_unlock;
6363
6364         inode = btrfs_new_inode(trans, root, dir, dentry->d_name.name,
6365                                 dentry->d_name.len, btrfs_ino(dir), objectid,
6366                                 mode, &index);
6367         if (IS_ERR(inode)) {
6368                 err = PTR_ERR(inode);
6369                 goto out_unlock;
6370         }
6371
6372         /*
6373         * If the active LSM wants to access the inode during
6374         * d_instantiate it needs these. Smack checks to see
6375         * if the filesystem supports xattrs by looking at the
6376         * ops vector.
6377         */
6378         inode->i_op = &btrfs_special_inode_operations;
6379         init_special_inode(inode, inode->i_mode, rdev);
6380
6381         err = btrfs_init_inode_security(trans, inode, dir, &dentry->d_name);
6382         if (err)
6383                 goto out_unlock_inode;
6384
6385         err = btrfs_add_nondir(trans, dir, dentry, inode, 0, index);
6386         if (err) {
6387                 goto out_unlock_inode;
6388         } else {
6389                 btrfs_update_inode(trans, root, inode);
6390                 unlock_new_inode(inode);
6391                 d_instantiate(dentry, inode);
6392         }
6393
6394 out_unlock:
6395         btrfs_end_transaction(trans, root);
6396         btrfs_balance_delayed_items(root);
6397         btrfs_btree_balance_dirty(root);
6398         if (drop_inode) {
6399                 inode_dec_link_count(inode);
6400                 iput(inode);
6401         }
6402         return err;
6403
6404 out_unlock_inode:
6405         drop_inode = 1;
6406         unlock_new_inode(inode);
6407         goto out_unlock;
6408
6409 }
6410
6411 static int btrfs_create(struct inode *dir, struct dentry *dentry,
6412                         umode_t mode, bool excl)
6413 {
6414         struct btrfs_trans_handle *trans;
6415         struct btrfs_root *root = BTRFS_I(dir)->root;
6416         struct inode *inode = NULL;
6417         int drop_inode_on_err = 0;
6418         int err;
6419         u64 objectid;
6420         u64 index = 0;
6421
6422         /*
6423          * 2 for inode item and ref
6424          * 2 for dir items
6425          * 1 for xattr if selinux is on
6426          */
6427         trans = btrfs_start_transaction(root, 5);
6428         if (IS_ERR(trans))
6429                 return PTR_ERR(trans);
6430
6431         err = btrfs_find_free_ino(root, &objectid);
6432         if (err)
6433                 goto out_unlock;
6434
6435         inode = btrfs_new_inode(trans, root, dir, dentry->d_name.name,
6436                                 dentry->d_name.len, btrfs_ino(dir), objectid,
6437                                 mode, &index);
6438         if (IS_ERR(inode)) {
6439                 err = PTR_ERR(inode);
6440                 goto out_unlock;
6441         }
6442         drop_inode_on_err = 1;
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_fop = &btrfs_file_operations;
6450         inode->i_op = &btrfs_file_inode_operations;
6451         inode->i_mapping->a_ops = &btrfs_aops;
6452
6453         err = btrfs_init_inode_security(trans, inode, dir, &dentry->d_name);
6454         if (err)
6455                 goto out_unlock_inode;
6456
6457         err = btrfs_update_inode(trans, root, inode);
6458         if (err)
6459                 goto out_unlock_inode;
6460
6461         err = btrfs_add_nondir(trans, dir, dentry, inode, 0, index);
6462         if (err)
6463                 goto out_unlock_inode;
6464
6465         BTRFS_I(inode)->io_tree.ops = &btrfs_extent_io_ops;
6466         unlock_new_inode(inode);
6467         d_instantiate(dentry, inode);
6468
6469 out_unlock:
6470         btrfs_end_transaction(trans, root);
6471         if (err && drop_inode_on_err) {
6472                 inode_dec_link_count(inode);
6473                 iput(inode);
6474         }
6475         btrfs_balance_delayed_items(root);
6476         btrfs_btree_balance_dirty(root);
6477         return err;
6478
6479 out_unlock_inode:
6480         unlock_new_inode(inode);
6481         goto out_unlock;
6482
6483 }
6484
6485 static int btrfs_link(struct dentry *old_dentry, struct inode *dir,
6486                       struct dentry *dentry)
6487 {
6488         struct btrfs_trans_handle *trans = NULL;
6489         struct btrfs_root *root = BTRFS_I(dir)->root;
6490         struct inode *inode = d_inode(old_dentry);
6491         u64 index;
6492         int err;
6493         int drop_inode = 0;
6494
6495         /* do not allow sys_link's with other subvols of the same device */
6496         if (root->objectid != BTRFS_I(inode)->root->objectid)
6497                 return -EXDEV;
6498
6499         if (inode->i_nlink >= BTRFS_LINK_MAX)
6500                 return -EMLINK;
6501
6502         err = btrfs_set_inode_index(dir, &index);
6503         if (err)
6504                 goto fail;
6505
6506         /*
6507          * 2 items for inode and inode ref
6508          * 2 items for dir items
6509          * 1 item for parent inode
6510          */
6511         trans = btrfs_start_transaction(root, 5);
6512         if (IS_ERR(trans)) {
6513                 err = PTR_ERR(trans);
6514                 trans = NULL;
6515                 goto fail;
6516         }
6517
6518         /* There are several dir indexes for this inode, clear the cache. */
6519         BTRFS_I(inode)->dir_index = 0ULL;
6520         inc_nlink(inode);
6521         inode_inc_iversion(inode);
6522         inode->i_ctime = current_fs_time(inode->i_sb);
6523         ihold(inode);
6524         set_bit(BTRFS_INODE_COPY_EVERYTHING, &BTRFS_I(inode)->runtime_flags);
6525
6526         err = btrfs_add_nondir(trans, dir, dentry, inode, 1, index);
6527
6528         if (err) {
6529                 drop_inode = 1;
6530         } else {
6531                 struct dentry *parent = dentry->d_parent;
6532                 err = btrfs_update_inode(trans, root, inode);
6533                 if (err)
6534                         goto fail;
6535                 if (inode->i_nlink == 1) {
6536                         /*
6537                          * If new hard link count is 1, it's a file created
6538                          * with open(2) O_TMPFILE flag.
6539                          */
6540                         err = btrfs_orphan_del(trans, inode);
6541                         if (err)
6542                                 goto fail;
6543                 }
6544                 d_instantiate(dentry, inode);
6545                 btrfs_log_new_name(trans, inode, NULL, parent);
6546         }
6547
6548         btrfs_balance_delayed_items(root);
6549 fail:
6550         if (trans)
6551                 btrfs_end_transaction(trans, root);
6552         if (drop_inode) {
6553                 inode_dec_link_count(inode);
6554                 iput(inode);
6555         }
6556         btrfs_btree_balance_dirty(root);
6557         return err;
6558 }
6559
6560 static int btrfs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
6561 {
6562         struct inode *inode = NULL;
6563         struct btrfs_trans_handle *trans;
6564         struct btrfs_root *root = BTRFS_I(dir)->root;
6565         int err = 0;
6566         int drop_on_err = 0;
6567         u64 objectid = 0;
6568         u64 index = 0;
6569
6570         /*
6571          * 2 items for inode and ref
6572          * 2 items for dir items
6573          * 1 for xattr if selinux is on
6574          */
6575         trans = btrfs_start_transaction(root, 5);
6576         if (IS_ERR(trans))
6577                 return PTR_ERR(trans);
6578
6579         err = btrfs_find_free_ino(root, &objectid);
6580         if (err)
6581                 goto out_fail;
6582
6583         inode = btrfs_new_inode(trans, root, dir, dentry->d_name.name,
6584                                 dentry->d_name.len, btrfs_ino(dir), objectid,
6585                                 S_IFDIR | mode, &index);
6586         if (IS_ERR(inode)) {
6587                 err = PTR_ERR(inode);
6588                 goto out_fail;
6589         }
6590
6591         drop_on_err = 1;
6592         /* these must be set before we unlock the inode */
6593         inode->i_op = &btrfs_dir_inode_operations;
6594         inode->i_fop = &btrfs_dir_file_operations;
6595
6596         err = btrfs_init_inode_security(trans, inode, dir, &dentry->d_name);
6597         if (err)
6598                 goto out_fail_inode;
6599
6600         btrfs_i_size_write(inode, 0);
6601         err = btrfs_update_inode(trans, root, inode);
6602         if (err)
6603                 goto out_fail_inode;
6604
6605         err = btrfs_add_link(trans, dir, inode, dentry->d_name.name,
6606                              dentry->d_name.len, 0, index);
6607         if (err)
6608                 goto out_fail_inode;
6609
6610         d_instantiate(dentry, inode);
6611         /*
6612          * mkdir is special.  We're unlocking after we call d_instantiate
6613          * to avoid a race with nfsd calling d_instantiate.
6614          */
6615         unlock_new_inode(inode);
6616         drop_on_err = 0;
6617
6618 out_fail:
6619         btrfs_end_transaction(trans, root);
6620         if (drop_on_err) {
6621                 inode_dec_link_count(inode);
6622                 iput(inode);
6623         }
6624         btrfs_balance_delayed_items(root);
6625         btrfs_btree_balance_dirty(root);
6626         return err;
6627
6628 out_fail_inode:
6629         unlock_new_inode(inode);
6630         goto out_fail;
6631 }
6632
6633 /* Find next extent map of a given extent map, caller needs to ensure locks */
6634 static struct extent_map *next_extent_map(struct extent_map *em)
6635 {
6636         struct rb_node *next;
6637
6638         next = rb_next(&em->rb_node);
6639         if (!next)
6640                 return NULL;
6641         return container_of(next, struct extent_map, rb_node);
6642 }
6643
6644 static struct extent_map *prev_extent_map(struct extent_map *em)
6645 {
6646         struct rb_node *prev;
6647
6648         prev = rb_prev(&em->rb_node);
6649         if (!prev)
6650                 return NULL;
6651         return container_of(prev, struct extent_map, rb_node);
6652 }
6653
6654 /* helper for btfs_get_extent.  Given an existing extent in the tree,
6655  * the existing extent is the nearest extent to map_start,
6656  * and an extent that you want to insert, deal with overlap and insert
6657  * the best fitted new extent into the tree.
6658  */
6659 static int merge_extent_mapping(struct extent_map_tree *em_tree,
6660                                 struct extent_map *existing,
6661                                 struct extent_map *em,
6662                                 u64 map_start)
6663 {
6664         struct extent_map *prev;
6665         struct extent_map *next;
6666         u64 start;
6667         u64 end;
6668         u64 start_diff;
6669
6670         BUG_ON(map_start < em->start || map_start >= extent_map_end(em));
6671
6672         if (existing->start > map_start) {
6673                 next = existing;
6674                 prev = prev_extent_map(next);
6675         } else {
6676                 prev = existing;
6677                 next = next_extent_map(prev);
6678         }
6679
6680         start = prev ? extent_map_end(prev) : em->start;
6681         start = max_t(u64, start, em->start);
6682         end = next ? next->start : extent_map_end(em);
6683         end = min_t(u64, end, extent_map_end(em));
6684         start_diff = start - em->start;
6685         em->start = start;
6686         em->len = end - start;
6687         if (em->block_start < EXTENT_MAP_LAST_BYTE &&
6688             !test_bit(EXTENT_FLAG_COMPRESSED, &em->flags)) {
6689                 em->block_start += start_diff;
6690                 em->block_len -= start_diff;
6691         }
6692         return add_extent_mapping(em_tree, em, 0);
6693 }
6694
6695 static noinline int uncompress_inline(struct btrfs_path *path,
6696                                       struct page *page,
6697                                       size_t pg_offset, u64 extent_offset,
6698                                       struct btrfs_file_extent_item *item)
6699 {
6700         int ret;
6701         struct extent_buffer *leaf = path->nodes[0];
6702         char *tmp;
6703         size_t max_size;
6704         unsigned long inline_size;
6705         unsigned long ptr;
6706         int compress_type;
6707
6708         WARN_ON(pg_offset != 0);
6709         compress_type = btrfs_file_extent_compression(leaf, item);
6710         max_size = btrfs_file_extent_ram_bytes(leaf, item);
6711         inline_size = btrfs_file_extent_inline_item_len(leaf,
6712                                         btrfs_item_nr(path->slots[0]));
6713         tmp = kmalloc(inline_size, GFP_NOFS);
6714         if (!tmp)
6715                 return -ENOMEM;
6716         ptr = btrfs_file_extent_inline_start(item);
6717
6718         read_extent_buffer(leaf, tmp, ptr, inline_size);
6719
6720         max_size = min_t(unsigned long, PAGE_SIZE, max_size);
6721         ret = btrfs_decompress(compress_type, tmp, page,
6722                                extent_offset, inline_size, max_size);
6723         kfree(tmp);
6724         return ret;
6725 }
6726
6727 /*
6728  * a bit scary, this does extent mapping from logical file offset to the disk.
6729  * the ugly parts come from merging extents from the disk with the in-ram
6730  * representation.  This gets more complex because of the data=ordered code,
6731  * where the in-ram extents might be locked pending data=ordered completion.
6732  *
6733  * This also copies inline extents directly into the page.
6734  */
6735
6736 struct extent_map *btrfs_get_extent(struct inode *inode, struct page *page,
6737                                     size_t pg_offset, u64 start, u64 len,
6738                                     int create)
6739 {
6740         int ret;
6741         int err = 0;
6742         u64 extent_start = 0;
6743         u64 extent_end = 0;
6744         u64 objectid = btrfs_ino(inode);
6745         u32 found_type;
6746         struct btrfs_path *path = NULL;
6747         struct btrfs_root *root = BTRFS_I(inode)->root;
6748         struct btrfs_file_extent_item *item;
6749         struct extent_buffer *leaf;
6750         struct btrfs_key found_key;
6751         struct extent_map *em = NULL;
6752         struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
6753         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
6754         struct btrfs_trans_handle *trans = NULL;
6755         const bool new_inline = !page || create;
6756
6757 again:
6758         read_lock(&em_tree->lock);
6759         em = lookup_extent_mapping(em_tree, start, len);
6760         if (em)
6761                 em->bdev = root->fs_info->fs_devices->latest_bdev;
6762         read_unlock(&em_tree->lock);
6763
6764         if (em) {
6765                 if (em->start > start || em->start + em->len <= start)
6766                         free_extent_map(em);
6767                 else if (em->block_start == EXTENT_MAP_INLINE && page)
6768                         free_extent_map(em);
6769                 else
6770                         goto out;
6771         }
6772         em = alloc_extent_map();
6773         if (!em) {
6774                 err = -ENOMEM;
6775                 goto out;
6776         }
6777         em->bdev = root->fs_info->fs_devices->latest_bdev;
6778         em->start = EXTENT_MAP_HOLE;
6779         em->orig_start = EXTENT_MAP_HOLE;
6780         em->len = (u64)-1;
6781         em->block_len = (u64)-1;
6782
6783         if (!path) {
6784                 path = btrfs_alloc_path();
6785                 if (!path) {
6786                         err = -ENOMEM;
6787                         goto out;
6788                 }
6789                 /*
6790                  * Chances are we'll be called again, so go ahead and do
6791                  * readahead
6792                  */
6793                 path->reada = READA_FORWARD;
6794         }
6795
6796         ret = btrfs_lookup_file_extent(trans, root, path,
6797                                        objectid, start, trans != NULL);
6798         if (ret < 0) {
6799                 err = ret;
6800                 goto out;
6801         }
6802
6803         if (ret != 0) {
6804                 if (path->slots[0] == 0)
6805                         goto not_found;
6806                 path->slots[0]--;
6807         }
6808
6809         leaf = path->nodes[0];
6810         item = btrfs_item_ptr(leaf, path->slots[0],
6811                               struct btrfs_file_extent_item);
6812         /* are we inside the extent that was found? */
6813         btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
6814         found_type = found_key.type;
6815         if (found_key.objectid != objectid ||
6816             found_type != BTRFS_EXTENT_DATA_KEY) {
6817                 /*
6818                  * If we backup past the first extent we want to move forward
6819                  * and see if there is an extent in front of us, otherwise we'll
6820                  * say there is a hole for our whole search range which can
6821                  * cause problems.
6822                  */
6823                 extent_end = start;
6824                 goto next;
6825         }
6826
6827         found_type = btrfs_file_extent_type(leaf, item);
6828         extent_start = found_key.offset;
6829         if (found_type == BTRFS_FILE_EXTENT_REG ||
6830             found_type == BTRFS_FILE_EXTENT_PREALLOC) {
6831                 extent_end = extent_start +
6832                        btrfs_file_extent_num_bytes(leaf, item);
6833         } else if (found_type == BTRFS_FILE_EXTENT_INLINE) {
6834                 size_t size;
6835                 size = btrfs_file_extent_inline_len(leaf, path->slots[0], item);
6836                 extent_end = ALIGN(extent_start + size, root->sectorsize);
6837         }
6838 next:
6839         if (start >= extent_end) {
6840                 path->slots[0]++;
6841                 if (path->slots[0] >= btrfs_header_nritems(leaf)) {
6842                         ret = btrfs_next_leaf(root, path);
6843                         if (ret < 0) {
6844                                 err = ret;
6845                                 goto out;
6846                         }
6847                         if (ret > 0)
6848                                 goto not_found;
6849                         leaf = path->nodes[0];
6850                 }
6851                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
6852                 if (found_key.objectid != objectid ||
6853                     found_key.type != BTRFS_EXTENT_DATA_KEY)
6854                         goto not_found;
6855                 if (start + len <= found_key.offset)
6856                         goto not_found;
6857                 if (start > found_key.offset)
6858                         goto next;
6859                 em->start = start;
6860                 em->orig_start = start;
6861                 em->len = found_key.offset - start;
6862                 goto not_found_em;
6863         }
6864
6865         btrfs_extent_item_to_extent_map(inode, path, item, new_inline, em);
6866
6867         if (found_type == BTRFS_FILE_EXTENT_REG ||
6868             found_type == BTRFS_FILE_EXTENT_PREALLOC) {
6869                 goto insert;
6870         } else if (found_type == BTRFS_FILE_EXTENT_INLINE) {
6871                 unsigned long ptr;
6872                 char *map;
6873                 size_t size;
6874                 size_t extent_offset;
6875                 size_t copy_size;
6876
6877                 if (new_inline)
6878                         goto out;
6879
6880                 size = btrfs_file_extent_inline_len(leaf, path->slots[0], item);
6881                 extent_offset = page_offset(page) + pg_offset - extent_start;
6882                 copy_size = min_t(u64, PAGE_SIZE - pg_offset,
6883                                   size - extent_offset);
6884                 em->start = extent_start + extent_offset;
6885                 em->len = ALIGN(copy_size, root->sectorsize);
6886                 em->orig_block_len = em->len;
6887                 em->orig_start = em->start;
6888                 ptr = btrfs_file_extent_inline_start(item) + extent_offset;
6889                 if (create == 0 && !PageUptodate(page)) {
6890                         if (btrfs_file_extent_compression(leaf, item) !=
6891                             BTRFS_COMPRESS_NONE) {
6892                                 ret = uncompress_inline(path, page, pg_offset,
6893                                                         extent_offset, item);
6894                                 if (ret) {
6895                                         err = ret;
6896                                         goto out;
6897                                 }
6898                         } else {
6899                                 map = kmap(page);
6900                                 read_extent_buffer(leaf, map + pg_offset, ptr,
6901                                                    copy_size);
6902                                 if (pg_offset + copy_size < PAGE_SIZE) {
6903                                         memset(map + pg_offset + copy_size, 0,
6904                                                PAGE_SIZE - pg_offset -
6905                                                copy_size);
6906                                 }
6907                                 kunmap(page);
6908                         }
6909                         flush_dcache_page(page);
6910                 } else if (create && PageUptodate(page)) {
6911                         BUG();
6912                         if (!trans) {
6913                                 kunmap(page);
6914                                 free_extent_map(em);
6915                                 em = NULL;
6916
6917                                 btrfs_release_path(path);
6918                                 trans = btrfs_join_transaction(root);
6919
6920                                 if (IS_ERR(trans))
6921                                         return ERR_CAST(trans);
6922                                 goto again;
6923                         }
6924                         map = kmap(page);
6925                         write_extent_buffer(leaf, map + pg_offset, ptr,
6926                                             copy_size);
6927                         kunmap(page);
6928                         btrfs_mark_buffer_dirty(leaf);
6929                 }
6930                 set_extent_uptodate(io_tree, em->start,
6931                                     extent_map_end(em) - 1, NULL, GFP_NOFS);
6932                 goto insert;
6933         }
6934 not_found:
6935         em->start = start;
6936         em->orig_start = start;
6937         em->len = len;
6938 not_found_em:
6939         em->block_start = EXTENT_MAP_HOLE;
6940         set_bit(EXTENT_FLAG_VACANCY, &em->flags);
6941 insert:
6942         btrfs_release_path(path);
6943         if (em->start > start || extent_map_end(em) <= start) {
6944                 btrfs_err(root->fs_info, "bad extent! em: [%llu %llu] passed [%llu %llu]",
6945                         em->start, em->len, start, len);
6946                 err = -EIO;
6947                 goto out;
6948         }
6949
6950         err = 0;
6951         write_lock(&em_tree->lock);
6952         ret = add_extent_mapping(em_tree, em, 0);
6953         /* it is possible that someone inserted the extent into the tree
6954          * while we had the lock dropped.  It is also possible that
6955          * an overlapping map exists in the tree
6956          */
6957         if (ret == -EEXIST) {
6958                 struct extent_map *existing;
6959
6960                 ret = 0;
6961
6962                 existing = search_extent_mapping(em_tree, start, len);
6963                 /*
6964                  * existing will always be non-NULL, since there must be
6965                  * extent causing the -EEXIST.
6966                  */
6967                 if (start >= extent_map_end(existing) ||
6968                     start <= existing->start) {
6969                         /*
6970                          * The existing extent map is the one nearest to
6971                          * the [start, start + len) range which overlaps
6972                          */
6973                         err = merge_extent_mapping(em_tree, existing,
6974                                                    em, start);
6975                         free_extent_map(existing);
6976                         if (err) {
6977                                 free_extent_map(em);
6978                                 em = NULL;
6979                         }
6980                 } else {
6981                         free_extent_map(em);
6982                         em = existing;
6983                         err = 0;
6984                 }
6985         }
6986         write_unlock(&em_tree->lock);
6987 out:
6988
6989         trace_btrfs_get_extent(root, em);
6990
6991         btrfs_free_path(path);
6992         if (trans) {
6993                 ret = btrfs_end_transaction(trans, root);
6994                 if (!err)
6995                         err = ret;
6996         }
6997         if (err) {
6998                 free_extent_map(em);
6999                 return ERR_PTR(err);
7000         }
7001         BUG_ON(!em); /* Error is always set */
7002         return em;
7003 }
7004
7005 struct extent_map *btrfs_get_extent_fiemap(struct inode *inode, struct page *page,
7006                                            size_t pg_offset, u64 start, u64 len,
7007                                            int create)
7008 {
7009         struct extent_map *em;
7010         struct extent_map *hole_em = NULL;
7011         u64 range_start = start;
7012         u64 end;
7013         u64 found;
7014         u64 found_end;
7015         int err = 0;
7016
7017         em = btrfs_get_extent(inode, page, pg_offset, start, len, create);
7018         if (IS_ERR(em))
7019                 return em;
7020         if (em) {
7021                 /*
7022                  * if our em maps to
7023                  * -  a hole or
7024                  * -  a pre-alloc extent,
7025                  * there might actually be delalloc bytes behind it.
7026                  */
7027                 if (em->block_start != EXTENT_MAP_HOLE &&
7028                     !test_bit(EXTENT_FLAG_PREALLOC, &em->flags))
7029                         return em;
7030                 else
7031                         hole_em = em;
7032         }
7033
7034         /* check to see if we've wrapped (len == -1 or similar) */
7035         end = start + len;
7036         if (end < start)
7037                 end = (u64)-1;
7038         else
7039                 end -= 1;
7040
7041         em = NULL;
7042
7043         /* ok, we didn't find anything, lets look for delalloc */
7044         found = count_range_bits(&BTRFS_I(inode)->io_tree, &range_start,
7045                                  end, len, EXTENT_DELALLOC, 1);
7046         found_end = range_start + found;
7047         if (found_end < range_start)
7048                 found_end = (u64)-1;
7049
7050         /*
7051          * we didn't find anything useful, return
7052          * the original results from get_extent()
7053          */
7054         if (range_start > end || found_end <= start) {
7055                 em = hole_em;
7056                 hole_em = NULL;
7057                 goto out;
7058         }
7059
7060         /* adjust the range_start to make sure it doesn't
7061          * go backwards from the start they passed in
7062          */
7063         range_start = max(start, range_start);
7064         found = found_end - range_start;
7065
7066         if (found > 0) {
7067                 u64 hole_start = start;
7068                 u64 hole_len = len;
7069
7070                 em = alloc_extent_map();
7071                 if (!em) {
7072                         err = -ENOMEM;
7073                         goto out;
7074                 }
7075                 /*
7076                  * when btrfs_get_extent can't find anything it
7077                  * returns one huge hole
7078                  *
7079                  * make sure what it found really fits our range, and
7080                  * adjust to make sure it is based on the start from
7081                  * the caller
7082                  */
7083                 if (hole_em) {
7084                         u64 calc_end = extent_map_end(hole_em);
7085
7086                         if (calc_end <= start || (hole_em->start > end)) {
7087                                 free_extent_map(hole_em);
7088                                 hole_em = NULL;
7089                         } else {
7090                                 hole_start = max(hole_em->start, start);
7091                                 hole_len = calc_end - hole_start;
7092                         }
7093                 }
7094                 em->bdev = NULL;
7095                 if (hole_em && range_start > hole_start) {
7096                         /* our hole starts before our delalloc, so we
7097                          * have to return just the parts of the hole
7098                          * that go until  the delalloc starts
7099                          */
7100                         em->len = min(hole_len,
7101                                       range_start - hole_start);
7102                         em->start = hole_start;
7103                         em->orig_start = hole_start;
7104                         /*
7105                          * don't adjust block start at all,
7106                          * it is fixed at EXTENT_MAP_HOLE
7107                          */
7108                         em->block_start = hole_em->block_start;
7109                         em->block_len = hole_len;
7110                         if (test_bit(EXTENT_FLAG_PREALLOC, &hole_em->flags))
7111                                 set_bit(EXTENT_FLAG_PREALLOC, &em->flags);
7112                 } else {
7113                         em->start = range_start;
7114                         em->len = found;
7115                         em->orig_start = range_start;
7116                         em->block_start = EXTENT_MAP_DELALLOC;
7117                         em->block_len = found;
7118                 }
7119         } else if (hole_em) {
7120                 return hole_em;
7121         }
7122 out:
7123
7124         free_extent_map(hole_em);
7125         if (err) {
7126                 free_extent_map(em);
7127                 return ERR_PTR(err);
7128         }
7129         return em;
7130 }
7131
7132 static struct extent_map *btrfs_new_extent_direct(struct inode *inode,
7133                                                   u64 start, u64 len)
7134 {
7135         struct btrfs_root *root = BTRFS_I(inode)->root;
7136         struct extent_map *em;
7137         struct btrfs_key ins;
7138         u64 alloc_hint;
7139         int ret;
7140
7141         alloc_hint = get_extent_allocation_hint(inode, start, len);
7142         ret = btrfs_reserve_extent(root, len, root->sectorsize, 0,
7143                                    alloc_hint, &ins, 1, 1);
7144         if (ret)
7145                 return ERR_PTR(ret);
7146
7147         /*
7148          * Create the ordered extent before the extent map. This is to avoid
7149          * races with the fast fsync path that would lead to it logging file
7150          * extent items that point to disk extents that were not yet written to.
7151          * The fast fsync path collects ordered extents into a local list and
7152          * then collects all the new extent maps, so we must create the ordered
7153          * extent first and make sure the fast fsync path collects any new
7154          * ordered extents after collecting new extent maps as well.
7155          * The fsync path simply can not rely on inode_dio_wait() because it
7156          * causes deadlock with AIO.
7157          */
7158         ret = btrfs_add_ordered_extent_dio(inode, start, ins.objectid,
7159                                            ins.offset, ins.offset, 0);
7160         if (ret) {
7161                 btrfs_free_reserved_extent(root, ins.objectid, ins.offset, 1);
7162                 return ERR_PTR(ret);
7163         }
7164
7165         em = create_pinned_em(inode, start, ins.offset, start, ins.objectid,
7166                               ins.offset, ins.offset, ins.offset, 0);
7167         if (IS_ERR(em)) {
7168                 struct btrfs_ordered_extent *oe;
7169
7170                 btrfs_free_reserved_extent(root, ins.objectid, ins.offset, 1);
7171                 oe = btrfs_lookup_ordered_extent(inode, start);
7172                 ASSERT(oe);
7173                 if (WARN_ON(!oe))
7174                         return em;
7175                 set_bit(BTRFS_ORDERED_IOERR, &oe->flags);
7176                 set_bit(BTRFS_ORDERED_IO_DONE, &oe->flags);
7177                 btrfs_remove_ordered_extent(inode, oe);
7178                 /* Once for our lookup and once for the ordered extents tree. */
7179                 btrfs_put_ordered_extent(oe);
7180                 btrfs_put_ordered_extent(oe);
7181         }
7182         return em;
7183 }
7184
7185 /*
7186  * returns 1 when the nocow is safe, < 1 on error, 0 if the
7187  * block must be cow'd
7188  */
7189 noinline int can_nocow_extent(struct inode *inode, u64 offset, u64 *len,
7190                               u64 *orig_start, u64 *orig_block_len,
7191                               u64 *ram_bytes)
7192 {
7193         struct btrfs_trans_handle *trans;
7194         struct btrfs_path *path;
7195         int ret;
7196         struct extent_buffer *leaf;
7197         struct btrfs_root *root = BTRFS_I(inode)->root;
7198         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
7199         struct btrfs_file_extent_item *fi;
7200         struct btrfs_key key;
7201         u64 disk_bytenr;
7202         u64 backref_offset;
7203         u64 extent_end;
7204         u64 num_bytes;
7205         int slot;
7206         int found_type;
7207         bool nocow = (BTRFS_I(inode)->flags & BTRFS_INODE_NODATACOW);
7208
7209         path = btrfs_alloc_path();
7210         if (!path)
7211                 return -ENOMEM;
7212
7213         ret = btrfs_lookup_file_extent(NULL, root, path, btrfs_ino(inode),
7214                                        offset, 0);
7215         if (ret < 0)
7216                 goto out;
7217
7218         slot = path->slots[0];
7219         if (ret == 1) {
7220                 if (slot == 0) {
7221                         /* can't find the item, must cow */
7222                         ret = 0;
7223                         goto out;
7224                 }
7225                 slot--;
7226         }
7227         ret = 0;
7228         leaf = path->nodes[0];
7229         btrfs_item_key_to_cpu(leaf, &key, slot);
7230         if (key.objectid != btrfs_ino(inode) ||
7231             key.type != BTRFS_EXTENT_DATA_KEY) {
7232                 /* not our file or wrong item type, must cow */
7233                 goto out;
7234         }
7235
7236         if (key.offset > offset) {
7237                 /* Wrong offset, must cow */
7238                 goto out;
7239         }
7240
7241         fi = btrfs_item_ptr(leaf, slot, struct btrfs_file_extent_item);
7242         found_type = btrfs_file_extent_type(leaf, fi);
7243         if (found_type != BTRFS_FILE_EXTENT_REG &&
7244             found_type != BTRFS_FILE_EXTENT_PREALLOC) {
7245                 /* not a regular extent, must cow */
7246                 goto out;
7247         }
7248
7249         if (!nocow && found_type == BTRFS_FILE_EXTENT_REG)
7250                 goto out;
7251
7252         extent_end = key.offset + btrfs_file_extent_num_bytes(leaf, fi);
7253         if (extent_end <= offset)
7254                 goto out;
7255
7256         disk_bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
7257         if (disk_bytenr == 0)
7258                 goto out;
7259
7260         if (btrfs_file_extent_compression(leaf, fi) ||
7261             btrfs_file_extent_encryption(leaf, fi) ||
7262             btrfs_file_extent_other_encoding(leaf, fi))
7263                 goto out;
7264
7265         backref_offset = btrfs_file_extent_offset(leaf, fi);
7266
7267         if (orig_start) {
7268                 *orig_start = key.offset - backref_offset;
7269                 *orig_block_len = btrfs_file_extent_disk_num_bytes(leaf, fi);
7270                 *ram_bytes = btrfs_file_extent_ram_bytes(leaf, fi);
7271         }
7272
7273         if (btrfs_extent_readonly(root, disk_bytenr))
7274                 goto out;
7275
7276         num_bytes = min(offset + *len, extent_end) - offset;
7277         if (!nocow && found_type == BTRFS_FILE_EXTENT_PREALLOC) {
7278                 u64 range_end;
7279
7280                 range_end = round_up(offset + num_bytes, root->sectorsize) - 1;
7281                 ret = test_range_bit(io_tree, offset, range_end,
7282                                      EXTENT_DELALLOC, 0, NULL);
7283                 if (ret) {
7284                         ret = -EAGAIN;
7285                         goto out;
7286                 }
7287         }
7288
7289         btrfs_release_path(path);
7290
7291         /*
7292          * look for other files referencing this extent, if we
7293          * find any we must cow
7294          */
7295         trans = btrfs_join_transaction(root);
7296         if (IS_ERR(trans)) {
7297                 ret = 0;
7298                 goto out;
7299         }
7300
7301         ret = btrfs_cross_ref_exist(trans, root, btrfs_ino(inode),
7302                                     key.offset - backref_offset, disk_bytenr);
7303         btrfs_end_transaction(trans, root);
7304         if (ret) {
7305                 ret = 0;
7306                 goto out;
7307         }
7308
7309         /*
7310          * adjust disk_bytenr and num_bytes to cover just the bytes
7311          * in this extent we are about to write.  If there
7312          * are any csums in that range we have to cow in order
7313          * to keep the csums correct
7314          */
7315         disk_bytenr += backref_offset;
7316         disk_bytenr += offset - key.offset;
7317         if (csum_exist_in_range(root, disk_bytenr, num_bytes))
7318                                 goto out;
7319         /*
7320          * all of the above have passed, it is safe to overwrite this extent
7321          * without cow
7322          */
7323         *len = num_bytes;
7324         ret = 1;
7325 out:
7326         btrfs_free_path(path);
7327         return ret;
7328 }
7329
7330 bool btrfs_page_exists_in_range(struct inode *inode, loff_t start, loff_t end)
7331 {
7332         struct radix_tree_root *root = &inode->i_mapping->page_tree;
7333         int found = false;
7334         void **pagep = NULL;
7335         struct page *page = NULL;
7336         int start_idx;
7337         int end_idx;
7338
7339         start_idx = start >> PAGE_SHIFT;
7340
7341         /*
7342          * end is the last byte in the last page.  end == start is legal
7343          */
7344         end_idx = end >> PAGE_SHIFT;
7345
7346         rcu_read_lock();
7347
7348         /* Most of the code in this while loop is lifted from
7349          * find_get_page.  It's been modified to begin searching from a
7350          * page and return just the first page found in that range.  If the
7351          * found idx is less than or equal to the end idx then we know that
7352          * a page exists.  If no pages are found or if those pages are
7353          * outside of the range then we're fine (yay!) */
7354         while (page == NULL &&
7355                radix_tree_gang_lookup_slot(root, &pagep, NULL, start_idx, 1)) {
7356                 page = radix_tree_deref_slot(pagep);
7357                 if (unlikely(!page))
7358                         break;
7359
7360                 if (radix_tree_exception(page)) {
7361                         if (radix_tree_deref_retry(page)) {
7362                                 page = NULL;
7363                                 continue;
7364                         }
7365                         /*
7366                          * Otherwise, shmem/tmpfs must be storing a swap entry
7367                          * here as an exceptional entry: so return it without
7368                          * attempting to raise page count.
7369                          */
7370                         page = NULL;
7371                         break; /* TODO: Is this relevant for this use case? */
7372                 }
7373
7374                 if (!page_cache_get_speculative(page)) {
7375                         page = NULL;
7376                         continue;
7377                 }
7378
7379                 /*
7380                  * Has the page moved?
7381                  * This is part of the lockless pagecache protocol. See
7382                  * include/linux/pagemap.h for details.
7383                  */
7384                 if (unlikely(page != *pagep)) {
7385                         put_page(page);
7386                         page = NULL;
7387                 }
7388         }
7389
7390         if (page) {
7391                 if (page->index <= end_idx)
7392                         found = true;
7393                 put_page(page);
7394         }
7395
7396         rcu_read_unlock();
7397         return found;
7398 }
7399
7400 static int lock_extent_direct(struct inode *inode, u64 lockstart, u64 lockend,
7401                               struct extent_state **cached_state, int writing)
7402 {
7403         struct btrfs_ordered_extent *ordered;
7404         int ret = 0;
7405
7406         while (1) {
7407                 lock_extent_bits(&BTRFS_I(inode)->io_tree, lockstart, lockend,
7408                                  cached_state);
7409                 /*
7410                  * We're concerned with the entire range that we're going to be
7411                  * doing DIO to, so we need to make sure theres no ordered
7412                  * extents in this range.
7413                  */
7414                 ordered = btrfs_lookup_ordered_range(inode, lockstart,
7415                                                      lockend - lockstart + 1);
7416
7417                 /*
7418                  * We need to make sure there are no buffered pages in this
7419                  * range either, we could have raced between the invalidate in
7420                  * generic_file_direct_write and locking the extent.  The
7421                  * invalidate needs to happen so that reads after a write do not
7422                  * get stale data.
7423                  */
7424                 if (!ordered &&
7425                     (!writing ||
7426                      !btrfs_page_exists_in_range(inode, lockstart, lockend)))
7427                         break;
7428
7429                 unlock_extent_cached(&BTRFS_I(inode)->io_tree, lockstart, lockend,
7430                                      cached_state, GFP_NOFS);
7431
7432                 if (ordered) {
7433                         /*
7434                          * If we are doing a DIO read and the ordered extent we
7435                          * found is for a buffered write, we can not wait for it
7436                          * to complete and retry, because if we do so we can
7437                          * deadlock with concurrent buffered writes on page
7438                          * locks. This happens only if our DIO read covers more
7439                          * than one extent map, if at this point has already
7440                          * created an ordered extent for a previous extent map
7441                          * and locked its range in the inode's io tree, and a
7442                          * concurrent write against that previous extent map's
7443                          * range and this range started (we unlock the ranges
7444                          * in the io tree only when the bios complete and
7445                          * buffered writes always lock pages before attempting
7446                          * to lock range in the io tree).
7447                          */
7448                         if (writing ||
7449                             test_bit(BTRFS_ORDERED_DIRECT, &ordered->flags))
7450                                 btrfs_start_ordered_extent(inode, ordered, 1);
7451                         else
7452                                 ret = -ENOTBLK;
7453                         btrfs_put_ordered_extent(ordered);
7454                 } else {
7455                         /*
7456                          * We could trigger writeback for this range (and wait
7457                          * for it to complete) and then invalidate the pages for
7458                          * this range (through invalidate_inode_pages2_range()),
7459                          * but that can lead us to a deadlock with a concurrent
7460                          * call to readpages() (a buffered read or a defrag call
7461                          * triggered a readahead) on a page lock due to an
7462                          * ordered dio extent we created before but did not have
7463                          * yet a corresponding bio submitted (whence it can not
7464                          * complete), which makes readpages() wait for that
7465                          * ordered extent to complete while holding a lock on
7466                          * that page.
7467                          */
7468                         ret = -ENOTBLK;
7469                 }
7470
7471                 if (ret)
7472                         break;
7473
7474                 cond_resched();
7475         }
7476
7477         return ret;
7478 }
7479
7480 static struct extent_map *create_pinned_em(struct inode *inode, u64 start,
7481                                            u64 len, u64 orig_start,
7482                                            u64 block_start, u64 block_len,
7483                                            u64 orig_block_len, u64 ram_bytes,
7484                                            int type)
7485 {
7486         struct extent_map_tree *em_tree;
7487         struct extent_map *em;
7488         struct btrfs_root *root = BTRFS_I(inode)->root;
7489         int ret;
7490
7491         em_tree = &BTRFS_I(inode)->extent_tree;
7492         em = alloc_extent_map();
7493         if (!em)
7494                 return ERR_PTR(-ENOMEM);
7495
7496         em->start = start;
7497         em->orig_start = orig_start;
7498         em->mod_start = start;
7499         em->mod_len = len;
7500         em->len = len;
7501         em->block_len = block_len;
7502         em->block_start = block_start;
7503         em->bdev = root->fs_info->fs_devices->latest_bdev;
7504         em->orig_block_len = orig_block_len;
7505         em->ram_bytes = ram_bytes;
7506         em->generation = -1;
7507         set_bit(EXTENT_FLAG_PINNED, &em->flags);
7508         if (type == BTRFS_ORDERED_PREALLOC)
7509                 set_bit(EXTENT_FLAG_FILLING, &em->flags);
7510
7511         do {
7512                 btrfs_drop_extent_cache(inode, em->start,
7513                                 em->start + em->len - 1, 0);
7514                 write_lock(&em_tree->lock);
7515                 ret = add_extent_mapping(em_tree, em, 1);
7516                 write_unlock(&em_tree->lock);
7517         } while (ret == -EEXIST);
7518
7519         if (ret) {
7520                 free_extent_map(em);
7521                 return ERR_PTR(ret);
7522         }
7523
7524         return em;
7525 }
7526
7527 static void adjust_dio_outstanding_extents(struct inode *inode,
7528                                            struct btrfs_dio_data *dio_data,
7529                                            const u64 len)
7530 {
7531         unsigned num_extents;
7532
7533         num_extents = (unsigned) div64_u64(len + BTRFS_MAX_EXTENT_SIZE - 1,
7534                                            BTRFS_MAX_EXTENT_SIZE);
7535         /*
7536          * If we have an outstanding_extents count still set then we're
7537          * within our reservation, otherwise we need to adjust our inode
7538          * counter appropriately.
7539          */
7540         if (dio_data->outstanding_extents) {
7541                 dio_data->outstanding_extents -= num_extents;
7542         } else {
7543                 spin_lock(&BTRFS_I(inode)->lock);
7544                 BTRFS_I(inode)->outstanding_extents += num_extents;
7545                 spin_unlock(&BTRFS_I(inode)->lock);
7546         }
7547 }
7548
7549 static int btrfs_get_blocks_direct(struct inode *inode, sector_t iblock,
7550                                    struct buffer_head *bh_result, int create)
7551 {
7552         struct extent_map *em;
7553         struct btrfs_root *root = BTRFS_I(inode)->root;
7554         struct extent_state *cached_state = NULL;
7555         struct btrfs_dio_data *dio_data = NULL;
7556         u64 start = iblock << inode->i_blkbits;
7557         u64 lockstart, lockend;
7558         u64 len = bh_result->b_size;
7559         int unlock_bits = EXTENT_LOCKED;
7560         int ret = 0;
7561
7562         if (create)
7563                 unlock_bits |= EXTENT_DIRTY;
7564         else
7565                 len = min_t(u64, len, root->sectorsize);
7566
7567         lockstart = start;
7568         lockend = start + len - 1;
7569
7570         if (current->journal_info) {
7571                 /*
7572                  * Need to pull our outstanding extents and set journal_info to NULL so
7573                  * that anything that needs to check if there's a transction doesn't get
7574                  * confused.
7575                  */
7576                 dio_data = current->journal_info;
7577                 current->journal_info = NULL;
7578         }
7579
7580         /*
7581          * If this errors out it's because we couldn't invalidate pagecache for
7582          * this range and we need to fallback to buffered.
7583          */
7584         if (lock_extent_direct(inode, lockstart, lockend, &cached_state,
7585                                create)) {
7586                 ret = -ENOTBLK;
7587                 goto err;
7588         }
7589
7590         em = btrfs_get_extent(inode, NULL, 0, start, len, 0);
7591         if (IS_ERR(em)) {
7592                 ret = PTR_ERR(em);
7593                 goto unlock_err;
7594         }
7595
7596         /*
7597          * Ok for INLINE and COMPRESSED extents we need to fallback on buffered
7598          * io.  INLINE is special, and we could probably kludge it in here, but
7599          * it's still buffered so for safety lets just fall back to the generic
7600          * buffered path.
7601          *
7602          * For COMPRESSED we _have_ to read the entire extent in so we can
7603          * decompress it, so there will be buffering required no matter what we
7604          * do, so go ahead and fallback to buffered.
7605          *
7606          * We return -ENOTBLK because thats what makes DIO go ahead and go back
7607          * to buffered IO.  Don't blame me, this is the price we pay for using
7608          * the generic code.
7609          */
7610         if (test_bit(EXTENT_FLAG_COMPRESSED, &em->flags) ||
7611             em->block_start == EXTENT_MAP_INLINE) {
7612                 free_extent_map(em);
7613                 ret = -ENOTBLK;
7614                 goto unlock_err;
7615         }
7616
7617         /* Just a good old fashioned hole, return */
7618         if (!create && (em->block_start == EXTENT_MAP_HOLE ||
7619                         test_bit(EXTENT_FLAG_PREALLOC, &em->flags))) {
7620                 free_extent_map(em);
7621                 goto unlock_err;
7622         }
7623
7624         /*
7625          * We don't allocate a new extent in the following cases
7626          *
7627          * 1) The inode is marked as NODATACOW.  In this case we'll just use the
7628          * existing extent.
7629          * 2) The extent is marked as PREALLOC.  We're good to go here and can
7630          * just use the extent.
7631          *
7632          */
7633         if (!create) {
7634                 len = min(len, em->len - (start - em->start));
7635                 lockstart = start + len;
7636                 goto unlock;
7637         }
7638
7639         if (test_bit(EXTENT_FLAG_PREALLOC, &em->flags) ||
7640             ((BTRFS_I(inode)->flags & BTRFS_INODE_NODATACOW) &&
7641              em->block_start != EXTENT_MAP_HOLE)) {
7642                 int type;
7643                 u64 block_start, orig_start, orig_block_len, ram_bytes;
7644
7645                 if (test_bit(EXTENT_FLAG_PREALLOC, &em->flags))
7646                         type = BTRFS_ORDERED_PREALLOC;
7647                 else
7648                         type = BTRFS_ORDERED_NOCOW;
7649                 len = min(len, em->len - (start - em->start));
7650                 block_start = em->block_start + (start - em->start);
7651
7652                 if (can_nocow_extent(inode, start, &len, &orig_start,
7653                                      &orig_block_len, &ram_bytes) == 1) {
7654                         if (type == BTRFS_ORDERED_PREALLOC) {
7655                                 free_extent_map(em);
7656                                 em = create_pinned_em(inode, start, len,
7657                                                        orig_start,
7658                                                        block_start, len,
7659                                                        orig_block_len,
7660                                                        ram_bytes, type);
7661                                 if (IS_ERR(em)) {
7662                                         ret = PTR_ERR(em);
7663                                         goto unlock_err;
7664                                 }
7665                         }
7666
7667                         ret = btrfs_add_ordered_extent_dio(inode, start,
7668                                            block_start, len, len, type);
7669                         if (ret) {
7670                                 free_extent_map(em);
7671                                 goto unlock_err;
7672                         }
7673                         goto unlock;
7674                 }
7675         }
7676
7677         /*
7678          * this will cow the extent, reset the len in case we changed
7679          * it above
7680          */
7681         len = bh_result->b_size;
7682         free_extent_map(em);
7683         em = btrfs_new_extent_direct(inode, start, len);
7684         if (IS_ERR(em)) {
7685                 ret = PTR_ERR(em);
7686                 goto unlock_err;
7687         }
7688         len = min(len, em->len - (start - em->start));
7689 unlock:
7690         bh_result->b_blocknr = (em->block_start + (start - em->start)) >>
7691                 inode->i_blkbits;
7692         bh_result->b_size = len;
7693         bh_result->b_bdev = em->bdev;
7694         set_buffer_mapped(bh_result);
7695         if (create) {
7696                 if (!test_bit(EXTENT_FLAG_PREALLOC, &em->flags))
7697                         set_buffer_new(bh_result);
7698
7699                 /*
7700                  * Need to update the i_size under the extent lock so buffered
7701                  * readers will get the updated i_size when we unlock.
7702                  */
7703                 if (start + len > i_size_read(inode))
7704                         i_size_write(inode, start + len);
7705
7706                 adjust_dio_outstanding_extents(inode, dio_data, len);
7707                 btrfs_free_reserved_data_space(inode, start, len);
7708                 WARN_ON(dio_data->reserve < len);
7709                 dio_data->reserve -= len;
7710                 dio_data->unsubmitted_oe_range_end = start + len;
7711                 current->journal_info = dio_data;
7712         }
7713
7714         /*
7715          * In the case of write we need to clear and unlock the entire range,
7716          * in the case of read we need to unlock only the end area that we
7717          * aren't using if there is any left over space.
7718          */
7719         if (lockstart < lockend) {
7720                 clear_extent_bit(&BTRFS_I(inode)->io_tree, lockstart,
7721                                  lockend, unlock_bits, 1, 0,
7722                                  &cached_state, GFP_NOFS);
7723         } else {
7724                 free_extent_state(cached_state);
7725         }
7726
7727         free_extent_map(em);
7728
7729         return 0;
7730
7731 unlock_err:
7732         clear_extent_bit(&BTRFS_I(inode)->io_tree, lockstart, lockend,
7733                          unlock_bits, 1, 0, &cached_state, GFP_NOFS);
7734 err:
7735         if (dio_data)
7736                 current->journal_info = dio_data;
7737         /*
7738          * Compensate the delalloc release we do in btrfs_direct_IO() when we
7739          * write less data then expected, so that we don't underflow our inode's
7740          * outstanding extents counter.
7741          */
7742         if (create && dio_data)
7743                 adjust_dio_outstanding_extents(inode, dio_data, len);
7744
7745         return ret;
7746 }
7747
7748 static inline int submit_dio_repair_bio(struct inode *inode, struct bio *bio,
7749                                         int rw, int mirror_num)
7750 {
7751         struct btrfs_root *root = BTRFS_I(inode)->root;
7752         int ret;
7753
7754         BUG_ON(rw & REQ_WRITE);
7755
7756         bio_get(bio);
7757
7758         ret = btrfs_bio_wq_end_io(root->fs_info, bio,
7759                                   BTRFS_WQ_ENDIO_DIO_REPAIR);
7760         if (ret)
7761                 goto err;
7762
7763         ret = btrfs_map_bio(root, rw, bio, mirror_num, 0);
7764 err:
7765         bio_put(bio);
7766         return ret;
7767 }
7768
7769 static int btrfs_check_dio_repairable(struct inode *inode,
7770                                       struct bio *failed_bio,
7771                                       struct io_failure_record *failrec,
7772                                       int failed_mirror)
7773 {
7774         int num_copies;
7775
7776         num_copies = btrfs_num_copies(BTRFS_I(inode)->root->fs_info,
7777                                       failrec->logical, failrec->len);
7778         if (num_copies == 1) {
7779                 /*
7780                  * we only have a single copy of the data, so don't bother with
7781                  * all the retry and error correction code that follows. no
7782                  * matter what the error is, it is very likely to persist.
7783                  */
7784                 pr_debug("Check DIO Repairable: cannot repair, num_copies=%d, next_mirror %d, failed_mirror %d\n",
7785                          num_copies, failrec->this_mirror, failed_mirror);
7786                 return 0;
7787         }
7788
7789         failrec->failed_mirror = failed_mirror;
7790         failrec->this_mirror++;
7791         if (failrec->this_mirror == failed_mirror)
7792                 failrec->this_mirror++;
7793
7794         if (failrec->this_mirror > num_copies) {
7795                 pr_debug("Check DIO Repairable: (fail) num_copies=%d, next_mirror %d, failed_mirror %d\n",
7796                          num_copies, failrec->this_mirror, failed_mirror);
7797                 return 0;
7798         }
7799
7800         return 1;
7801 }
7802
7803 static int dio_read_error(struct inode *inode, struct bio *failed_bio,
7804                         struct page *page, unsigned int pgoff,
7805                         u64 start, u64 end, int failed_mirror,
7806                         bio_end_io_t *repair_endio, void *repair_arg)
7807 {
7808         struct io_failure_record *failrec;
7809         struct bio *bio;
7810         int isector;
7811         int read_mode;
7812         int ret;
7813
7814         BUG_ON(failed_bio->bi_rw & REQ_WRITE);
7815
7816         ret = btrfs_get_io_failure_record(inode, start, end, &failrec);
7817         if (ret)
7818                 return ret;
7819
7820         ret = btrfs_check_dio_repairable(inode, failed_bio, failrec,
7821                                          failed_mirror);
7822         if (!ret) {
7823                 free_io_failure(inode, failrec);
7824                 return -EIO;
7825         }
7826
7827         if ((failed_bio->bi_vcnt > 1)
7828                 || (failed_bio->bi_io_vec->bv_len
7829                         > BTRFS_I(inode)->root->sectorsize))
7830                 read_mode = READ_SYNC | REQ_FAILFAST_DEV;
7831         else
7832                 read_mode = READ_SYNC;
7833
7834         isector = start - btrfs_io_bio(failed_bio)->logical;
7835         isector >>= inode->i_sb->s_blocksize_bits;
7836         bio = btrfs_create_repair_bio(inode, failed_bio, failrec, page,
7837                                 pgoff, isector, repair_endio, repair_arg);
7838         if (!bio) {
7839                 free_io_failure(inode, failrec);
7840                 return -EIO;
7841         }
7842
7843         btrfs_debug(BTRFS_I(inode)->root->fs_info,
7844                     "Repair DIO Read Error: submitting new dio read[%#x] to this_mirror=%d, in_validation=%d\n",
7845                     read_mode, failrec->this_mirror, failrec->in_validation);
7846
7847         ret = submit_dio_repair_bio(inode, bio, read_mode,
7848                                     failrec->this_mirror);
7849         if (ret) {
7850                 free_io_failure(inode, failrec);
7851                 bio_put(bio);
7852         }
7853
7854         return ret;
7855 }
7856
7857 struct btrfs_retry_complete {
7858         struct completion done;
7859         struct inode *inode;
7860         u64 start;
7861         int uptodate;
7862 };
7863
7864 static void btrfs_retry_endio_nocsum(struct bio *bio)
7865 {
7866         struct btrfs_retry_complete *done = bio->bi_private;
7867         struct inode *inode;
7868         struct bio_vec *bvec;
7869         int i;
7870
7871         if (bio->bi_error)
7872                 goto end;
7873
7874         ASSERT(bio->bi_vcnt == 1);
7875         inode = bio->bi_io_vec->bv_page->mapping->host;
7876         ASSERT(bio->bi_io_vec->bv_len == BTRFS_I(inode)->root->sectorsize);
7877
7878         done->uptodate = 1;
7879         bio_for_each_segment_all(bvec, bio, i)
7880                 clean_io_failure(done->inode, done->start, bvec->bv_page, 0);
7881 end:
7882         complete(&done->done);
7883         bio_put(bio);
7884 }
7885
7886 static int __btrfs_correct_data_nocsum(struct inode *inode,
7887                                        struct btrfs_io_bio *io_bio)
7888 {
7889         struct btrfs_fs_info *fs_info;
7890         struct bio_vec *bvec;
7891         struct btrfs_retry_complete done;
7892         u64 start;
7893         unsigned int pgoff;
7894         u32 sectorsize;
7895         int nr_sectors;
7896         int i;
7897         int ret;
7898
7899         fs_info = BTRFS_I(inode)->root->fs_info;
7900         sectorsize = BTRFS_I(inode)->root->sectorsize;
7901
7902         start = io_bio->logical;
7903         done.inode = inode;
7904
7905         bio_for_each_segment_all(bvec, &io_bio->bio, i) {
7906                 nr_sectors = BTRFS_BYTES_TO_BLKS(fs_info, bvec->bv_len);
7907                 pgoff = bvec->bv_offset;
7908
7909 next_block_or_try_again:
7910                 done.uptodate = 0;
7911                 done.start = start;
7912                 init_completion(&done.done);
7913
7914                 ret = dio_read_error(inode, &io_bio->bio, bvec->bv_page,
7915                                 pgoff, start, start + sectorsize - 1,
7916                                 io_bio->mirror_num,
7917                                 btrfs_retry_endio_nocsum, &done);
7918                 if (ret)
7919                         return ret;
7920
7921                 wait_for_completion(&done.done);
7922
7923                 if (!done.uptodate) {
7924                         /* We might have another mirror, so try again */
7925                         goto next_block_or_try_again;
7926                 }
7927
7928                 start += sectorsize;
7929
7930                 if (nr_sectors--) {
7931                         pgoff += sectorsize;
7932                         goto next_block_or_try_again;
7933                 }
7934         }
7935
7936         return 0;
7937 }
7938
7939 static void btrfs_retry_endio(struct bio *bio)
7940 {
7941         struct btrfs_retry_complete *done = bio->bi_private;
7942         struct btrfs_io_bio *io_bio = btrfs_io_bio(bio);
7943         struct inode *inode;
7944         struct bio_vec *bvec;
7945         u64 start;
7946         int uptodate;
7947         int ret;
7948         int i;
7949
7950         if (bio->bi_error)
7951                 goto end;
7952
7953         uptodate = 1;
7954
7955         start = done->start;
7956
7957         ASSERT(bio->bi_vcnt == 1);
7958         inode = bio->bi_io_vec->bv_page->mapping->host;
7959         ASSERT(bio->bi_io_vec->bv_len == BTRFS_I(inode)->root->sectorsize);
7960
7961         bio_for_each_segment_all(bvec, bio, i) {
7962                 ret = __readpage_endio_check(done->inode, io_bio, i,
7963                                         bvec->bv_page, bvec->bv_offset,
7964                                         done->start, bvec->bv_len);
7965                 if (!ret)
7966                         clean_io_failure(done->inode, done->start,
7967                                         bvec->bv_page, bvec->bv_offset);
7968                 else
7969                         uptodate = 0;
7970         }
7971
7972         done->uptodate = uptodate;
7973 end:
7974         complete(&done->done);
7975         bio_put(bio);
7976 }
7977
7978 static int __btrfs_subio_endio_read(struct inode *inode,
7979                                     struct btrfs_io_bio *io_bio, int err)
7980 {
7981         struct btrfs_fs_info *fs_info;
7982         struct bio_vec *bvec;
7983         struct btrfs_retry_complete done;
7984         u64 start;
7985         u64 offset = 0;
7986         u32 sectorsize;
7987         int nr_sectors;
7988         unsigned int pgoff;
7989         int csum_pos;
7990         int i;
7991         int ret;
7992
7993         fs_info = BTRFS_I(inode)->root->fs_info;
7994         sectorsize = BTRFS_I(inode)->root->sectorsize;
7995
7996         err = 0;
7997         start = io_bio->logical;
7998         done.inode = inode;
7999
8000         bio_for_each_segment_all(bvec, &io_bio->bio, i) {
8001                 nr_sectors = BTRFS_BYTES_TO_BLKS(fs_info, bvec->bv_len);
8002
8003                 pgoff = bvec->bv_offset;
8004 next_block:
8005                 csum_pos = BTRFS_BYTES_TO_BLKS(fs_info, offset);
8006                 ret = __readpage_endio_check(inode, io_bio, csum_pos,
8007                                         bvec->bv_page, pgoff, start,
8008                                         sectorsize);
8009                 if (likely(!ret))
8010                         goto next;
8011 try_again:
8012                 done.uptodate = 0;
8013                 done.start = start;
8014                 init_completion(&done.done);
8015
8016                 ret = dio_read_error(inode, &io_bio->bio, bvec->bv_page,
8017                                 pgoff, start, start + sectorsize - 1,
8018                                 io_bio->mirror_num,
8019                                 btrfs_retry_endio, &done);
8020                 if (ret) {
8021                         err = ret;
8022                         goto next;
8023                 }
8024
8025                 wait_for_completion(&done.done);
8026
8027                 if (!done.uptodate) {
8028                         /* We might have another mirror, so try again */
8029                         goto try_again;
8030                 }
8031 next:
8032                 offset += sectorsize;
8033                 start += sectorsize;
8034
8035                 ASSERT(nr_sectors);
8036
8037                 if (--nr_sectors) {
8038                         pgoff += sectorsize;
8039                         goto next_block;
8040                 }
8041         }
8042
8043         return err;
8044 }
8045
8046 static int btrfs_subio_endio_read(struct inode *inode,
8047                                   struct btrfs_io_bio *io_bio, int err)
8048 {
8049         bool skip_csum = BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM;
8050
8051         if (skip_csum) {
8052                 if (unlikely(err))
8053                         return __btrfs_correct_data_nocsum(inode, io_bio);
8054                 else
8055                         return 0;
8056         } else {
8057                 return __btrfs_subio_endio_read(inode, io_bio, err);
8058         }
8059 }
8060
8061 static void btrfs_endio_direct_read(struct bio *bio)
8062 {
8063         struct btrfs_dio_private *dip = bio->bi_private;
8064         struct inode *inode = dip->inode;
8065         struct bio *dio_bio;
8066         struct btrfs_io_bio *io_bio = btrfs_io_bio(bio);
8067         int err = bio->bi_error;
8068
8069         if (dip->flags & BTRFS_DIO_ORIG_BIO_SUBMITTED)
8070                 err = btrfs_subio_endio_read(inode, io_bio, err);
8071
8072         unlock_extent(&BTRFS_I(inode)->io_tree, dip->logical_offset,
8073                       dip->logical_offset + dip->bytes - 1);
8074         dio_bio = dip->dio_bio;
8075
8076         kfree(dip);
8077
8078         dio_bio->bi_error = bio->bi_error;
8079         dio_end_io(dio_bio, bio->bi_error);
8080
8081         if (io_bio->end_io)
8082                 io_bio->end_io(io_bio, err);
8083         bio_put(bio);
8084 }
8085
8086 static void btrfs_endio_direct_write_update_ordered(struct inode *inode,
8087                                                     const u64 offset,
8088                                                     const u64 bytes,
8089                                                     const int uptodate)
8090 {
8091         struct btrfs_root *root = BTRFS_I(inode)->root;
8092         struct btrfs_ordered_extent *ordered = NULL;
8093         u64 ordered_offset = offset;
8094         u64 ordered_bytes = bytes;
8095         int ret;
8096
8097 again:
8098         ret = btrfs_dec_test_first_ordered_pending(inode, &ordered,
8099                                                    &ordered_offset,
8100                                                    ordered_bytes,
8101                                                    uptodate);
8102         if (!ret)
8103                 goto out_test;
8104
8105         btrfs_init_work(&ordered->work, btrfs_endio_write_helper,
8106                         finish_ordered_fn, NULL, NULL);
8107         btrfs_queue_work(root->fs_info->endio_write_workers,
8108                          &ordered->work);
8109 out_test:
8110         /*
8111          * our bio might span multiple ordered extents.  If we haven't
8112          * completed the accounting for the whole dio, go back and try again
8113          */
8114         if (ordered_offset < offset + bytes) {
8115                 ordered_bytes = offset + bytes - ordered_offset;
8116                 ordered = NULL;
8117                 goto again;
8118         }
8119 }
8120
8121 static void btrfs_endio_direct_write(struct bio *bio)
8122 {
8123         struct btrfs_dio_private *dip = bio->bi_private;
8124         struct bio *dio_bio = dip->dio_bio;
8125
8126         btrfs_endio_direct_write_update_ordered(dip->inode,
8127                                                 dip->logical_offset,
8128                                                 dip->bytes,
8129                                                 !bio->bi_error);
8130
8131         kfree(dip);
8132
8133         dio_bio->bi_error = bio->bi_error;
8134         dio_end_io(dio_bio, bio->bi_error);
8135         bio_put(bio);
8136 }
8137
8138 static int __btrfs_submit_bio_start_direct_io(struct inode *inode, int rw,
8139                                     struct bio *bio, int mirror_num,
8140                                     unsigned long bio_flags, u64 offset)
8141 {
8142         int ret;
8143         struct btrfs_root *root = BTRFS_I(inode)->root;
8144         ret = btrfs_csum_one_bio(root, inode, bio, offset, 1);
8145         BUG_ON(ret); /* -ENOMEM */
8146         return 0;
8147 }
8148
8149 static void btrfs_end_dio_bio(struct bio *bio)
8150 {
8151         struct btrfs_dio_private *dip = bio->bi_private;
8152         int err = bio->bi_error;
8153
8154         if (err)
8155                 btrfs_warn(BTRFS_I(dip->inode)->root->fs_info,
8156                            "direct IO failed ino %llu rw %lu sector %#Lx len %u err no %d",
8157                            btrfs_ino(dip->inode), bio->bi_rw,
8158                            (unsigned long long)bio->bi_iter.bi_sector,
8159                            bio->bi_iter.bi_size, err);
8160
8161         if (dip->subio_endio)
8162                 err = dip->subio_endio(dip->inode, btrfs_io_bio(bio), err);
8163
8164         if (err) {
8165                 dip->errors = 1;
8166
8167                 /*
8168                  * before atomic variable goto zero, we must make sure
8169                  * dip->errors is perceived to be set.
8170                  */
8171                 smp_mb__before_atomic();
8172         }
8173
8174         /* if there are more bios still pending for this dio, just exit */
8175         if (!atomic_dec_and_test(&dip->pending_bios))
8176                 goto out;
8177
8178         if (dip->errors) {
8179                 bio_io_error(dip->orig_bio);
8180         } else {
8181                 dip->dio_bio->bi_error = 0;
8182                 bio_endio(dip->orig_bio);
8183         }
8184 out:
8185         bio_put(bio);
8186 }
8187
8188 static struct bio *btrfs_dio_bio_alloc(struct block_device *bdev,
8189                                        u64 first_sector, gfp_t gfp_flags)
8190 {
8191         struct bio *bio;
8192         bio = btrfs_bio_alloc(bdev, first_sector, BIO_MAX_PAGES, gfp_flags);
8193         if (bio)
8194                 bio_associate_current(bio);
8195         return bio;
8196 }
8197
8198 static inline int btrfs_lookup_and_bind_dio_csum(struct btrfs_root *root,
8199                                                  struct inode *inode,
8200                                                  struct btrfs_dio_private *dip,
8201                                                  struct bio *bio,
8202                                                  u64 file_offset)
8203 {
8204         struct btrfs_io_bio *io_bio = btrfs_io_bio(bio);
8205         struct btrfs_io_bio *orig_io_bio = btrfs_io_bio(dip->orig_bio);
8206         int ret;
8207
8208         /*
8209          * We load all the csum data we need when we submit
8210          * the first bio to reduce the csum tree search and
8211          * contention.
8212          */
8213         if (dip->logical_offset == file_offset) {
8214                 ret = btrfs_lookup_bio_sums_dio(root, inode, dip->orig_bio,
8215                                                 file_offset);
8216                 if (ret)
8217                         return ret;
8218         }
8219
8220         if (bio == dip->orig_bio)
8221                 return 0;
8222
8223         file_offset -= dip->logical_offset;
8224         file_offset >>= inode->i_sb->s_blocksize_bits;
8225         io_bio->csum = (u8 *)(((u32 *)orig_io_bio->csum) + file_offset);
8226
8227         return 0;
8228 }
8229
8230 static inline int __btrfs_submit_dio_bio(struct bio *bio, struct inode *inode,
8231                                          int rw, u64 file_offset, int skip_sum,
8232                                          int async_submit)
8233 {
8234         struct btrfs_dio_private *dip = bio->bi_private;
8235         int write = rw & REQ_WRITE;
8236         struct btrfs_root *root = BTRFS_I(inode)->root;
8237         int ret;
8238
8239         if (async_submit)
8240                 async_submit = !atomic_read(&BTRFS_I(inode)->sync_writers);
8241
8242         bio_get(bio);
8243
8244         if (!write) {
8245                 ret = btrfs_bio_wq_end_io(root->fs_info, bio,
8246                                 BTRFS_WQ_ENDIO_DATA);
8247                 if (ret)
8248                         goto err;
8249         }
8250
8251         if (skip_sum)
8252                 goto map;
8253
8254         if (write && async_submit) {
8255                 ret = btrfs_wq_submit_bio(root->fs_info,
8256                                    inode, rw, bio, 0, 0,
8257                                    file_offset,
8258                                    __btrfs_submit_bio_start_direct_io,
8259                                    __btrfs_submit_bio_done);
8260                 goto err;
8261         } else if (write) {
8262                 /*
8263                  * If we aren't doing async submit, calculate the csum of the
8264                  * bio now.
8265                  */
8266                 ret = btrfs_csum_one_bio(root, inode, bio, file_offset, 1);
8267                 if (ret)
8268                         goto err;
8269         } else {
8270                 ret = btrfs_lookup_and_bind_dio_csum(root, inode, dip, bio,
8271                                                      file_offset);
8272                 if (ret)
8273                         goto err;
8274         }
8275 map:
8276         ret = btrfs_map_bio(root, rw, bio, 0, async_submit);
8277 err:
8278         bio_put(bio);
8279         return ret;
8280 }
8281
8282 static int btrfs_submit_direct_hook(int rw, struct btrfs_dio_private *dip,
8283                                     int skip_sum)
8284 {
8285         struct inode *inode = dip->inode;
8286         struct btrfs_root *root = BTRFS_I(inode)->root;
8287         struct bio *bio;
8288         struct bio *orig_bio = dip->orig_bio;
8289         struct bio_vec *bvec = orig_bio->bi_io_vec;
8290         u64 start_sector = orig_bio->bi_iter.bi_sector;
8291         u64 file_offset = dip->logical_offset;
8292         u64 submit_len = 0;
8293         u64 map_length;
8294         u32 blocksize = root->sectorsize;
8295         int async_submit = 0;
8296         int nr_sectors;
8297         int ret;
8298         int i;
8299
8300         map_length = orig_bio->bi_iter.bi_size;
8301         ret = btrfs_map_block(root->fs_info, rw, start_sector << 9,
8302                               &map_length, NULL, 0);
8303         if (ret)
8304                 return -EIO;
8305
8306         if (map_length >= orig_bio->bi_iter.bi_size) {
8307                 bio = orig_bio;
8308                 dip->flags |= BTRFS_DIO_ORIG_BIO_SUBMITTED;
8309                 goto submit;
8310         }
8311
8312         /* async crcs make it difficult to collect full stripe writes. */
8313         if (btrfs_get_alloc_profile(root, 1) & BTRFS_BLOCK_GROUP_RAID56_MASK)
8314                 async_submit = 0;
8315         else
8316                 async_submit = 1;
8317
8318         bio = btrfs_dio_bio_alloc(orig_bio->bi_bdev, start_sector, GFP_NOFS);
8319         if (!bio)
8320                 return -ENOMEM;
8321
8322         bio->bi_private = dip;
8323         bio->bi_end_io = btrfs_end_dio_bio;
8324         btrfs_io_bio(bio)->logical = file_offset;
8325         atomic_inc(&dip->pending_bios);
8326
8327         while (bvec <= (orig_bio->bi_io_vec + orig_bio->bi_vcnt - 1)) {
8328                 nr_sectors = BTRFS_BYTES_TO_BLKS(root->fs_info, bvec->bv_len);
8329                 i = 0;
8330 next_block:
8331                 if (unlikely(map_length < submit_len + blocksize ||
8332                     bio_add_page(bio, bvec->bv_page, blocksize,
8333                             bvec->bv_offset + (i * blocksize)) < blocksize)) {
8334                         /*
8335                          * inc the count before we submit the bio so
8336                          * we know the end IO handler won't happen before
8337                          * we inc the count. Otherwise, the dip might get freed
8338                          * before we're done setting it up
8339                          */
8340                         atomic_inc(&dip->pending_bios);
8341                         ret = __btrfs_submit_dio_bio(bio, inode, rw,
8342                                                      file_offset, skip_sum,
8343                                                      async_submit);
8344                         if (ret) {
8345                                 bio_put(bio);
8346                                 atomic_dec(&dip->pending_bios);
8347                                 goto out_err;
8348                         }
8349
8350                         start_sector += submit_len >> 9;
8351                         file_offset += submit_len;
8352
8353                         submit_len = 0;
8354
8355                         bio = btrfs_dio_bio_alloc(orig_bio->bi_bdev,
8356                                                   start_sector, GFP_NOFS);
8357                         if (!bio)
8358                                 goto out_err;
8359                         bio->bi_private = dip;
8360                         bio->bi_end_io = btrfs_end_dio_bio;
8361                         btrfs_io_bio(bio)->logical = file_offset;
8362
8363                         map_length = orig_bio->bi_iter.bi_size;
8364                         ret = btrfs_map_block(root->fs_info, rw,
8365                                               start_sector << 9,
8366                                               &map_length, NULL, 0);
8367                         if (ret) {
8368                                 bio_put(bio);
8369                                 goto out_err;
8370                         }
8371
8372                         goto next_block;
8373                 } else {
8374                         submit_len += blocksize;
8375                         if (--nr_sectors) {
8376                                 i++;
8377                                 goto next_block;
8378                         }
8379                         bvec++;
8380                 }
8381         }
8382
8383 submit:
8384         ret = __btrfs_submit_dio_bio(bio, inode, rw, file_offset, skip_sum,
8385                                      async_submit);
8386         if (!ret)
8387                 return 0;
8388
8389         bio_put(bio);
8390 out_err:
8391         dip->errors = 1;
8392         /*
8393          * before atomic variable goto zero, we must
8394          * make sure dip->errors is perceived to be set.
8395          */
8396         smp_mb__before_atomic();
8397         if (atomic_dec_and_test(&dip->pending_bios))
8398                 bio_io_error(dip->orig_bio);
8399
8400         /* bio_end_io() will handle error, so we needn't return it */
8401         return 0;
8402 }
8403
8404 static void btrfs_submit_direct(int rw, struct bio *dio_bio,
8405                                 struct inode *inode, loff_t file_offset)
8406 {
8407         struct btrfs_dio_private *dip = NULL;
8408         struct bio *io_bio = NULL;
8409         struct btrfs_io_bio *btrfs_bio;
8410         int skip_sum;
8411         int write = rw & REQ_WRITE;
8412         int ret = 0;
8413
8414         skip_sum = BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM;
8415
8416         io_bio = btrfs_bio_clone(dio_bio, GFP_NOFS);
8417         if (!io_bio) {
8418                 ret = -ENOMEM;
8419                 goto free_ordered;
8420         }
8421
8422         dip = kzalloc(sizeof(*dip), GFP_NOFS);
8423         if (!dip) {
8424                 ret = -ENOMEM;
8425                 goto free_ordered;
8426         }
8427
8428         dip->private = dio_bio->bi_private;
8429         dip->inode = inode;
8430         dip->logical_offset = file_offset;
8431         dip->bytes = dio_bio->bi_iter.bi_size;
8432         dip->disk_bytenr = (u64)dio_bio->bi_iter.bi_sector << 9;
8433         io_bio->bi_private = dip;
8434         dip->orig_bio = io_bio;
8435         dip->dio_bio = dio_bio;
8436         atomic_set(&dip->pending_bios, 0);
8437         btrfs_bio = btrfs_io_bio(io_bio);
8438         btrfs_bio->logical = file_offset;
8439
8440         if (write) {
8441                 io_bio->bi_end_io = btrfs_endio_direct_write;
8442         } else {
8443                 io_bio->bi_end_io = btrfs_endio_direct_read;
8444                 dip->subio_endio = btrfs_subio_endio_read;
8445         }
8446
8447         /*
8448          * Reset the range for unsubmitted ordered extents (to a 0 length range)
8449          * even if we fail to submit a bio, because in such case we do the
8450          * corresponding error handling below and it must not be done a second
8451          * time by btrfs_direct_IO().
8452          */
8453         if (write) {
8454                 struct btrfs_dio_data *dio_data = current->journal_info;
8455
8456                 dio_data->unsubmitted_oe_range_end = dip->logical_offset +
8457                         dip->bytes;
8458                 dio_data->unsubmitted_oe_range_start =
8459                         dio_data->unsubmitted_oe_range_end;
8460         }
8461
8462         ret = btrfs_submit_direct_hook(rw, dip, skip_sum);
8463         if (!ret)
8464                 return;
8465
8466         if (btrfs_bio->end_io)
8467                 btrfs_bio->end_io(btrfs_bio, ret);
8468
8469 free_ordered:
8470         /*
8471          * If we arrived here it means either we failed to submit the dip
8472          * or we either failed to clone the dio_bio or failed to allocate the
8473          * dip. If we cloned the dio_bio and allocated the dip, we can just
8474          * call bio_endio against our io_bio so that we get proper resource
8475          * cleanup if we fail to submit the dip, otherwise, we must do the
8476          * same as btrfs_endio_direct_[write|read] because we can't call these
8477          * callbacks - they require an allocated dip and a clone of dio_bio.
8478          */
8479         if (io_bio && dip) {
8480                 io_bio->bi_error = -EIO;
8481                 bio_endio(io_bio);
8482                 /*
8483                  * The end io callbacks free our dip, do the final put on io_bio
8484                  * and all the cleanup and final put for dio_bio (through
8485                  * dio_end_io()).
8486                  */
8487                 dip = NULL;
8488                 io_bio = NULL;
8489         } else {
8490                 if (write)
8491                         btrfs_endio_direct_write_update_ordered(inode,
8492                                                 file_offset,
8493                                                 dio_bio->bi_iter.bi_size,
8494                                                 0);
8495                 else
8496                         unlock_extent(&BTRFS_I(inode)->io_tree, file_offset,
8497                               file_offset + dio_bio->bi_iter.bi_size - 1);
8498
8499                 dio_bio->bi_error = -EIO;
8500                 /*
8501                  * Releases and cleans up our dio_bio, no need to bio_put()
8502                  * nor bio_endio()/bio_io_error() against dio_bio.
8503                  */
8504                 dio_end_io(dio_bio, ret);
8505         }
8506         if (io_bio)
8507                 bio_put(io_bio);
8508         kfree(dip);
8509 }
8510
8511 static ssize_t check_direct_IO(struct btrfs_root *root, struct kiocb *iocb,
8512                         const struct iov_iter *iter, loff_t offset)
8513 {
8514         int seg;
8515         int i;
8516         unsigned blocksize_mask = root->sectorsize - 1;
8517         ssize_t retval = -EINVAL;
8518
8519         if (offset & blocksize_mask)
8520                 goto out;
8521
8522         if (iov_iter_alignment(iter) & blocksize_mask)
8523                 goto out;
8524
8525         /* If this is a write we don't need to check anymore */
8526         if (iov_iter_rw(iter) == WRITE)
8527                 return 0;
8528         /*
8529          * Check to make sure we don't have duplicate iov_base's in this
8530          * iovec, if so return EINVAL, otherwise we'll get csum errors
8531          * when reading back.
8532          */
8533         for (seg = 0; seg < iter->nr_segs; seg++) {
8534                 for (i = seg + 1; i < iter->nr_segs; i++) {
8535                         if (iter->iov[seg].iov_base == iter->iov[i].iov_base)
8536                                 goto out;
8537                 }
8538         }
8539         retval = 0;
8540 out:
8541         return retval;
8542 }
8543
8544 static ssize_t btrfs_direct_IO(struct kiocb *iocb, struct iov_iter *iter,
8545                                loff_t offset)
8546 {
8547         struct file *file = iocb->ki_filp;
8548         struct inode *inode = file->f_mapping->host;
8549         struct btrfs_root *root = BTRFS_I(inode)->root;
8550         struct btrfs_dio_data dio_data = { 0 };
8551         size_t count = 0;
8552         int flags = 0;
8553         bool wakeup = true;
8554         bool relock = false;
8555         ssize_t ret;
8556
8557         if (check_direct_IO(BTRFS_I(inode)->root, iocb, iter, offset))
8558                 return 0;
8559
8560         inode_dio_begin(inode);
8561         smp_mb__after_atomic();
8562
8563         /*
8564          * The generic stuff only does filemap_write_and_wait_range, which
8565          * isn't enough if we've written compressed pages to this area, so
8566          * we need to flush the dirty pages again to make absolutely sure
8567          * that any outstanding dirty pages are on disk.
8568          */
8569         count = iov_iter_count(iter);
8570         if (test_bit(BTRFS_INODE_HAS_ASYNC_EXTENT,
8571                      &BTRFS_I(inode)->runtime_flags))
8572                 filemap_fdatawrite_range(inode->i_mapping, offset,
8573                                          offset + count - 1);
8574
8575         if (iov_iter_rw(iter) == WRITE) {
8576                 /*
8577                  * If the write DIO is beyond the EOF, we need update
8578                  * the isize, but it is protected by i_mutex. So we can
8579                  * not unlock the i_mutex at this case.
8580                  */
8581                 if (offset + count <= inode->i_size) {
8582                         inode_unlock(inode);
8583                         relock = true;
8584                 }
8585                 ret = btrfs_delalloc_reserve_space(inode, offset, count);
8586                 if (ret)
8587                         goto out;
8588                 dio_data.outstanding_extents = div64_u64(count +
8589                                                 BTRFS_MAX_EXTENT_SIZE - 1,
8590                                                 BTRFS_MAX_EXTENT_SIZE);
8591
8592                 /*
8593                  * We need to know how many extents we reserved so that we can
8594                  * do the accounting properly if we go over the number we
8595                  * originally calculated.  Abuse current->journal_info for this.
8596                  */
8597                 dio_data.reserve = round_up(count, root->sectorsize);
8598                 dio_data.unsubmitted_oe_range_start = (u64)offset;
8599                 dio_data.unsubmitted_oe_range_end = (u64)offset;
8600                 current->journal_info = &dio_data;
8601         } else if (test_bit(BTRFS_INODE_READDIO_NEED_LOCK,
8602                                      &BTRFS_I(inode)->runtime_flags)) {
8603                 inode_dio_end(inode);
8604                 flags = DIO_LOCKING | DIO_SKIP_HOLES;
8605                 wakeup = false;
8606         }
8607
8608         ret = __blockdev_direct_IO(iocb, inode,
8609                                    BTRFS_I(inode)->root->fs_info->fs_devices->latest_bdev,
8610                                    iter, offset, btrfs_get_blocks_direct, NULL,
8611                                    btrfs_submit_direct, flags);
8612         if (iov_iter_rw(iter) == WRITE) {
8613                 current->journal_info = NULL;
8614                 if (ret < 0 && ret != -EIOCBQUEUED) {
8615                         if (dio_data.reserve)
8616                                 btrfs_delalloc_release_space(inode, offset,
8617                                                              dio_data.reserve);
8618                         /*
8619                          * On error we might have left some ordered extents
8620                          * without submitting corresponding bios for them, so
8621                          * cleanup them up to avoid other tasks getting them
8622                          * and waiting for them to complete forever.
8623                          */
8624                         if (dio_data.unsubmitted_oe_range_start <
8625                             dio_data.unsubmitted_oe_range_end)
8626                                 btrfs_endio_direct_write_update_ordered(inode,
8627                                         dio_data.unsubmitted_oe_range_start,
8628                                         dio_data.unsubmitted_oe_range_end -
8629                                         dio_data.unsubmitted_oe_range_start,
8630                                         0);
8631                 } else if (ret >= 0 && (size_t)ret < count)
8632                         btrfs_delalloc_release_space(inode, offset,
8633                                                      count - (size_t)ret);
8634         }
8635 out:
8636         if (wakeup)
8637                 inode_dio_end(inode);
8638         if (relock)
8639                 inode_lock(inode);
8640
8641         return ret;
8642 }
8643
8644 #define BTRFS_FIEMAP_FLAGS      (FIEMAP_FLAG_SYNC)
8645
8646 static int btrfs_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
8647                 __u64 start, __u64 len)
8648 {
8649         int     ret;
8650
8651         ret = fiemap_check_flags(fieinfo, BTRFS_FIEMAP_FLAGS);
8652         if (ret)
8653                 return ret;
8654
8655         return extent_fiemap(inode, fieinfo, start, len, btrfs_get_extent_fiemap);
8656 }
8657
8658 int btrfs_readpage(struct file *file, struct page *page)
8659 {
8660         struct extent_io_tree *tree;
8661         tree = &BTRFS_I(page->mapping->host)->io_tree;
8662         return extent_read_full_page(tree, page, btrfs_get_extent, 0);
8663 }
8664
8665 static int btrfs_writepage(struct page *page, struct writeback_control *wbc)
8666 {
8667         struct extent_io_tree *tree;
8668         struct inode *inode = page->mapping->host;
8669         int ret;
8670
8671         if (current->flags & PF_MEMALLOC) {
8672                 redirty_page_for_writepage(wbc, page);
8673                 unlock_page(page);
8674                 return 0;
8675         }
8676
8677         /*
8678          * If we are under memory pressure we will call this directly from the
8679          * VM, we need to make sure we have the inode referenced for the ordered
8680          * extent.  If not just return like we didn't do anything.
8681          */
8682         if (!igrab(inode)) {
8683                 redirty_page_for_writepage(wbc, page);
8684                 return AOP_WRITEPAGE_ACTIVATE;
8685         }
8686         tree = &BTRFS_I(page->mapping->host)->io_tree;
8687         ret = extent_write_full_page(tree, page, btrfs_get_extent, wbc);
8688         btrfs_add_delayed_iput(inode);
8689         return ret;
8690 }
8691
8692 static int btrfs_writepages(struct address_space *mapping,
8693                             struct writeback_control *wbc)
8694 {
8695         struct extent_io_tree *tree;
8696
8697         tree = &BTRFS_I(mapping->host)->io_tree;
8698         return extent_writepages(tree, mapping, btrfs_get_extent, wbc);
8699 }
8700
8701 static int
8702 btrfs_readpages(struct file *file, struct address_space *mapping,
8703                 struct list_head *pages, unsigned nr_pages)
8704 {
8705         struct extent_io_tree *tree;
8706         tree = &BTRFS_I(mapping->host)->io_tree;
8707         return extent_readpages(tree, mapping, pages, nr_pages,
8708                                 btrfs_get_extent);
8709 }
8710 static int __btrfs_releasepage(struct page *page, gfp_t gfp_flags)
8711 {
8712         struct extent_io_tree *tree;
8713         struct extent_map_tree *map;
8714         int ret;
8715
8716         tree = &BTRFS_I(page->mapping->host)->io_tree;
8717         map = &BTRFS_I(page->mapping->host)->extent_tree;
8718         ret = try_release_extent_mapping(map, tree, page, gfp_flags);
8719         if (ret == 1) {
8720                 ClearPagePrivate(page);
8721                 set_page_private(page, 0);
8722                 put_page(page);
8723         }
8724         return ret;
8725 }
8726
8727 static int btrfs_releasepage(struct page *page, gfp_t gfp_flags)
8728 {
8729         if (PageWriteback(page) || PageDirty(page))
8730                 return 0;
8731         return __btrfs_releasepage(page, gfp_flags & GFP_NOFS);
8732 }
8733
8734 static void btrfs_invalidatepage(struct page *page, unsigned int offset,
8735                                  unsigned int length)
8736 {
8737         struct inode *inode = page->mapping->host;
8738         struct extent_io_tree *tree;
8739         struct btrfs_ordered_extent *ordered;
8740         struct extent_state *cached_state = NULL;
8741         u64 page_start = page_offset(page);
8742         u64 page_end = page_start + PAGE_SIZE - 1;
8743         u64 start;
8744         u64 end;
8745         int inode_evicting = inode->i_state & I_FREEING;
8746
8747         /*
8748          * we have the page locked, so new writeback can't start,
8749          * and the dirty bit won't be cleared while we are here.
8750          *
8751          * Wait for IO on this page so that we can safely clear
8752          * the PagePrivate2 bit and do ordered accounting
8753          */
8754         wait_on_page_writeback(page);
8755
8756         tree = &BTRFS_I(inode)->io_tree;
8757         if (offset) {
8758                 btrfs_releasepage(page, GFP_NOFS);
8759                 return;
8760         }
8761
8762         if (!inode_evicting)
8763                 lock_extent_bits(tree, page_start, page_end, &cached_state);
8764 again:
8765         start = page_start;
8766         ordered = btrfs_lookup_ordered_range(inode, start,
8767                                         page_end - start + 1);
8768         if (ordered) {
8769                 end = min(page_end, ordered->file_offset + ordered->len - 1);
8770                 /*
8771                  * IO on this page will never be started, so we need
8772                  * to account for any ordered extents now
8773                  */
8774                 if (!inode_evicting)
8775                         clear_extent_bit(tree, start, end,
8776                                          EXTENT_DIRTY | EXTENT_DELALLOC |
8777                                          EXTENT_LOCKED | EXTENT_DO_ACCOUNTING |
8778                                          EXTENT_DEFRAG, 1, 0, &cached_state,
8779                                          GFP_NOFS);
8780                 /*
8781                  * whoever cleared the private bit is responsible
8782                  * for the finish_ordered_io
8783                  */
8784                 if (TestClearPagePrivate2(page)) {
8785                         struct btrfs_ordered_inode_tree *tree;
8786                         u64 new_len;
8787
8788                         tree = &BTRFS_I(inode)->ordered_tree;
8789
8790                         spin_lock_irq(&tree->lock);
8791                         set_bit(BTRFS_ORDERED_TRUNCATED, &ordered->flags);
8792                         new_len = start - ordered->file_offset;
8793                         if (new_len < ordered->truncated_len)
8794                                 ordered->truncated_len = new_len;
8795                         spin_unlock_irq(&tree->lock);
8796
8797                         if (btrfs_dec_test_ordered_pending(inode, &ordered,
8798                                                            start,
8799                                                            end - start + 1, 1))
8800                                 btrfs_finish_ordered_io(ordered);
8801                 }
8802                 btrfs_put_ordered_extent(ordered);
8803                 if (!inode_evicting) {
8804                         cached_state = NULL;
8805                         lock_extent_bits(tree, start, end,
8806                                          &cached_state);
8807                 }
8808
8809                 start = end + 1;
8810                 if (start < page_end)
8811                         goto again;
8812         }
8813
8814         /*
8815          * Qgroup reserved space handler
8816          * Page here will be either
8817          * 1) Already written to disk
8818          *    In this case, its reserved space is released from data rsv map
8819          *    and will be freed by delayed_ref handler finally.
8820          *    So even we call qgroup_free_data(), it won't decrease reserved
8821          *    space.
8822          * 2) Not written to disk
8823          *    This means the reserved space should be freed here.
8824          */
8825         btrfs_qgroup_free_data(inode, page_start, PAGE_SIZE);
8826         if (!inode_evicting) {
8827                 clear_extent_bit(tree, page_start, page_end,
8828                                  EXTENT_LOCKED | EXTENT_DIRTY |
8829                                  EXTENT_DELALLOC | EXTENT_DO_ACCOUNTING |
8830                                  EXTENT_DEFRAG, 1, 1,
8831                                  &cached_state, GFP_NOFS);
8832
8833                 __btrfs_releasepage(page, GFP_NOFS);
8834         }
8835
8836         ClearPageChecked(page);
8837         if (PagePrivate(page)) {
8838                 ClearPagePrivate(page);
8839                 set_page_private(page, 0);
8840                 put_page(page);
8841         }
8842 }
8843
8844 /*
8845  * btrfs_page_mkwrite() is not allowed to change the file size as it gets
8846  * called from a page fault handler when a page is first dirtied. Hence we must
8847  * be careful to check for EOF conditions here. We set the page up correctly
8848  * for a written page which means we get ENOSPC checking when writing into
8849  * holes and correct delalloc and unwritten extent mapping on filesystems that
8850  * support these features.
8851  *
8852  * We are not allowed to take the i_mutex here so we have to play games to
8853  * protect against truncate races as the page could now be beyond EOF.  Because
8854  * vmtruncate() writes the inode size before removing pages, once we have the
8855  * page lock we can determine safely if the page is beyond EOF. If it is not
8856  * beyond EOF, then the page is guaranteed safe against truncation until we
8857  * unlock the page.
8858  */
8859 int btrfs_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf)
8860 {
8861         struct page *page = vmf->page;
8862         struct inode *inode = file_inode(vma->vm_file);
8863         struct btrfs_root *root = BTRFS_I(inode)->root;
8864         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
8865         struct btrfs_ordered_extent *ordered;
8866         struct extent_state *cached_state = NULL;
8867         char *kaddr;
8868         unsigned long zero_start;
8869         loff_t size;
8870         int ret;
8871         int reserved = 0;
8872         u64 reserved_space;
8873         u64 page_start;
8874         u64 page_end;
8875         u64 end;
8876
8877         reserved_space = PAGE_SIZE;
8878
8879         sb_start_pagefault(inode->i_sb);
8880         page_start = page_offset(page);
8881         page_end = page_start + PAGE_SIZE - 1;
8882         end = page_end;
8883
8884         /*
8885          * Reserving delalloc space after obtaining the page lock can lead to
8886          * deadlock. For example, if a dirty page is locked by this function
8887          * and the call to btrfs_delalloc_reserve_space() ends up triggering
8888          * dirty page write out, then the btrfs_writepage() function could
8889          * end up waiting indefinitely to get a lock on the page currently
8890          * being processed by btrfs_page_mkwrite() function.
8891          */
8892         ret = btrfs_delalloc_reserve_space(inode, page_start,
8893                                            reserved_space);
8894         if (!ret) {
8895                 ret = file_update_time(vma->vm_file);
8896                 reserved = 1;
8897         }
8898         if (ret) {
8899                 if (ret == -ENOMEM)
8900                         ret = VM_FAULT_OOM;
8901                 else /* -ENOSPC, -EIO, etc */
8902                         ret = VM_FAULT_SIGBUS;
8903                 if (reserved)
8904                         goto out;
8905                 goto out_noreserve;
8906         }
8907
8908         ret = VM_FAULT_NOPAGE; /* make the VM retry the fault */
8909 again:
8910         lock_page(page);
8911         size = i_size_read(inode);
8912
8913         if ((page->mapping != inode->i_mapping) ||
8914             (page_start >= size)) {
8915                 /* page got truncated out from underneath us */
8916                 goto out_unlock;
8917         }
8918         wait_on_page_writeback(page);
8919
8920         lock_extent_bits(io_tree, page_start, page_end, &cached_state);
8921         set_page_extent_mapped(page);
8922
8923         /*
8924          * we can't set the delalloc bits if there are pending ordered
8925          * extents.  Drop our locks and wait for them to finish
8926          */
8927         ordered = btrfs_lookup_ordered_range(inode, page_start, page_end);
8928         if (ordered) {
8929                 unlock_extent_cached(io_tree, page_start, page_end,
8930                                      &cached_state, GFP_NOFS);
8931                 unlock_page(page);
8932                 btrfs_start_ordered_extent(inode, ordered, 1);
8933                 btrfs_put_ordered_extent(ordered);
8934                 goto again;
8935         }
8936
8937         if (page->index == ((size - 1) >> PAGE_SHIFT)) {
8938                 reserved_space = round_up(size - page_start, root->sectorsize);
8939                 if (reserved_space < PAGE_SIZE) {
8940                         end = page_start + reserved_space - 1;
8941                         spin_lock(&BTRFS_I(inode)->lock);
8942                         BTRFS_I(inode)->outstanding_extents++;
8943                         spin_unlock(&BTRFS_I(inode)->lock);
8944                         btrfs_delalloc_release_space(inode, page_start,
8945                                                 PAGE_SIZE - reserved_space);
8946                 }
8947         }
8948
8949         /*
8950          * XXX - page_mkwrite gets called every time the page is dirtied, even
8951          * if it was already dirty, so for space accounting reasons we need to
8952          * clear any delalloc bits for the range we are fixing to save.  There
8953          * is probably a better way to do this, but for now keep consistent with
8954          * prepare_pages in the normal write path.
8955          */
8956         clear_extent_bit(&BTRFS_I(inode)->io_tree, page_start, end,
8957                           EXTENT_DIRTY | EXTENT_DELALLOC |
8958                           EXTENT_DO_ACCOUNTING | EXTENT_DEFRAG,
8959                           0, 0, &cached_state, GFP_NOFS);
8960
8961         ret = btrfs_set_extent_delalloc(inode, page_start, end,
8962                                         &cached_state);
8963         if (ret) {
8964                 unlock_extent_cached(io_tree, page_start, page_end,
8965                                      &cached_state, GFP_NOFS);
8966                 ret = VM_FAULT_SIGBUS;
8967                 goto out_unlock;
8968         }
8969         ret = 0;
8970
8971         /* page is wholly or partially inside EOF */
8972         if (page_start + PAGE_SIZE > size)
8973                 zero_start = size & ~PAGE_MASK;
8974         else
8975                 zero_start = PAGE_SIZE;
8976
8977         if (zero_start != PAGE_SIZE) {
8978                 kaddr = kmap(page);
8979                 memset(kaddr + zero_start, 0, PAGE_SIZE - zero_start);
8980                 flush_dcache_page(page);
8981                 kunmap(page);
8982         }
8983         ClearPageChecked(page);
8984         set_page_dirty(page);
8985         SetPageUptodate(page);
8986
8987         BTRFS_I(inode)->last_trans = root->fs_info->generation;
8988         BTRFS_I(inode)->last_sub_trans = BTRFS_I(inode)->root->log_transid;
8989         BTRFS_I(inode)->last_log_commit = BTRFS_I(inode)->root->last_log_commit;
8990
8991         unlock_extent_cached(io_tree, page_start, page_end, &cached_state, GFP_NOFS);
8992
8993 out_unlock:
8994         if (!ret) {
8995                 sb_end_pagefault(inode->i_sb);
8996                 return VM_FAULT_LOCKED;
8997         }
8998         unlock_page(page);
8999 out:
9000         btrfs_delalloc_release_space(inode, page_start, reserved_space);
9001 out_noreserve:
9002         sb_end_pagefault(inode->i_sb);
9003         return ret;
9004 }
9005
9006 static int btrfs_truncate(struct inode *inode)
9007 {
9008         struct btrfs_root *root = BTRFS_I(inode)->root;
9009         struct btrfs_block_rsv *rsv;
9010         int ret = 0;
9011         int err = 0;
9012         struct btrfs_trans_handle *trans;
9013         u64 mask = root->sectorsize - 1;
9014         u64 min_size = btrfs_calc_trunc_metadata_size(root, 1);
9015
9016         ret = btrfs_wait_ordered_range(inode, inode->i_size & (~mask),
9017                                        (u64)-1);
9018         if (ret)
9019                 return ret;
9020
9021         /*
9022          * Yes ladies and gentelment, this is indeed ugly.  The fact is we have
9023          * 3 things going on here
9024          *
9025          * 1) We need to reserve space for our orphan item and the space to
9026          * delete our orphan item.  Lord knows we don't want to have a dangling
9027          * orphan item because we didn't reserve space to remove it.
9028          *
9029          * 2) We need to reserve space to update our inode.
9030          *
9031          * 3) We need to have something to cache all the space that is going to
9032          * be free'd up by the truncate operation, but also have some slack
9033          * space reserved in case it uses space during the truncate (thank you
9034          * very much snapshotting).
9035          *
9036          * And we need these to all be seperate.  The fact is we can use alot of
9037          * space doing the truncate, and we have no earthly idea how much space
9038          * we will use, so we need the truncate reservation to be seperate so it
9039          * doesn't end up using space reserved for updating the inode or
9040          * removing the orphan item.  We also need to be able to stop the
9041          * transaction and start a new one, which means we need to be able to
9042          * update the inode several times, and we have no idea of knowing how
9043          * many times that will be, so we can't just reserve 1 item for the
9044          * entirety of the opration, so that has to be done seperately as well.
9045          * Then there is the orphan item, which does indeed need to be held on
9046          * to for the whole operation, and we need nobody to touch this reserved
9047          * space except the orphan code.
9048          *
9049          * So that leaves us with
9050          *
9051          * 1) root->orphan_block_rsv - for the orphan deletion.
9052          * 2) rsv - for the truncate reservation, which we will steal from the
9053          * transaction reservation.
9054          * 3) fs_info->trans_block_rsv - this will have 1 items worth left for
9055          * updating the inode.
9056          */
9057         rsv = btrfs_alloc_block_rsv(root, BTRFS_BLOCK_RSV_TEMP);
9058         if (!rsv)
9059                 return -ENOMEM;
9060         rsv->size = min_size;
9061         rsv->failfast = 1;
9062
9063         /*
9064          * 1 for the truncate slack space
9065          * 1 for updating the inode.
9066          */
9067         trans = btrfs_start_transaction(root, 2);
9068         if (IS_ERR(trans)) {
9069                 err = PTR_ERR(trans);
9070                 goto out;
9071         }
9072
9073         /* Migrate the slack space for the truncate to our reserve */
9074         ret = btrfs_block_rsv_migrate(&root->fs_info->trans_block_rsv, rsv,
9075                                       min_size);
9076         BUG_ON(ret);
9077
9078         /*
9079          * So if we truncate and then write and fsync we normally would just
9080          * write the extents that changed, which is a problem if we need to
9081          * first truncate that entire inode.  So set this flag so we write out
9082          * all of the extents in the inode to the sync log so we're completely
9083          * safe.
9084          */
9085         set_bit(BTRFS_INODE_NEEDS_FULL_SYNC, &BTRFS_I(inode)->runtime_flags);
9086         trans->block_rsv = rsv;
9087
9088         while (1) {
9089                 ret = btrfs_truncate_inode_items(trans, root, inode,
9090                                                  inode->i_size,
9091                                                  BTRFS_EXTENT_DATA_KEY);
9092                 if (ret != -ENOSPC && ret != -EAGAIN) {
9093                         err = ret;
9094                         break;
9095                 }
9096
9097                 trans->block_rsv = &root->fs_info->trans_block_rsv;
9098                 ret = btrfs_update_inode(trans, root, inode);
9099                 if (ret) {
9100                         err = ret;
9101                         break;
9102                 }
9103
9104                 btrfs_end_transaction(trans, root);
9105                 btrfs_btree_balance_dirty(root);
9106
9107                 trans = btrfs_start_transaction(root, 2);
9108                 if (IS_ERR(trans)) {
9109                         ret = err = PTR_ERR(trans);
9110                         trans = NULL;
9111                         break;
9112                 }
9113
9114                 ret = btrfs_block_rsv_migrate(&root->fs_info->trans_block_rsv,
9115                                               rsv, min_size);
9116                 BUG_ON(ret);    /* shouldn't happen */
9117                 trans->block_rsv = rsv;
9118         }
9119
9120         if (ret == 0 && inode->i_nlink > 0) {
9121                 trans->block_rsv = root->orphan_block_rsv;
9122                 ret = btrfs_orphan_del(trans, inode);
9123                 if (ret)
9124                         err = ret;
9125         }
9126
9127         if (trans) {
9128                 trans->block_rsv = &root->fs_info->trans_block_rsv;
9129                 ret = btrfs_update_inode(trans, root, inode);
9130                 if (ret && !err)
9131                         err = ret;
9132
9133                 ret = btrfs_end_transaction(trans, root);
9134                 btrfs_btree_balance_dirty(root);
9135         }
9136
9137 out:
9138         btrfs_free_block_rsv(root, rsv);
9139
9140         if (ret && !err)
9141                 err = ret;
9142
9143         return err;
9144 }
9145
9146 /*
9147  * create a new subvolume directory/inode (helper for the ioctl).
9148  */
9149 int btrfs_create_subvol_root(struct btrfs_trans_handle *trans,
9150                              struct btrfs_root *new_root,
9151                              struct btrfs_root *parent_root,
9152                              u64 new_dirid)
9153 {
9154         struct inode *inode;
9155         int err;
9156         u64 index = 0;
9157
9158         inode = btrfs_new_inode(trans, new_root, NULL, "..", 2,
9159                                 new_dirid, new_dirid,
9160                                 S_IFDIR | (~current_umask() & S_IRWXUGO),
9161                                 &index);
9162         if (IS_ERR(inode))
9163                 return PTR_ERR(inode);
9164         inode->i_op = &btrfs_dir_inode_operations;
9165         inode->i_fop = &btrfs_dir_file_operations;
9166
9167         set_nlink(inode, 1);
9168         btrfs_i_size_write(inode, 0);
9169         unlock_new_inode(inode);
9170
9171         err = btrfs_subvol_inherit_props(trans, new_root, parent_root);
9172         if (err)
9173                 btrfs_err(new_root->fs_info,
9174                           "error inheriting subvolume %llu properties: %d",
9175                           new_root->root_key.objectid, err);
9176
9177         err = btrfs_update_inode(trans, new_root, inode);
9178
9179         iput(inode);
9180         return err;
9181 }
9182
9183 struct inode *btrfs_alloc_inode(struct super_block *sb)
9184 {
9185         struct btrfs_inode *ei;
9186         struct inode *inode;
9187
9188         ei = kmem_cache_alloc(btrfs_inode_cachep, GFP_NOFS);
9189         if (!ei)
9190                 return NULL;
9191
9192         ei->root = NULL;
9193         ei->generation = 0;
9194         ei->last_trans = 0;
9195         ei->last_sub_trans = 0;
9196         ei->logged_trans = 0;
9197         ei->delalloc_bytes = 0;
9198         ei->defrag_bytes = 0;
9199         ei->disk_i_size = 0;
9200         ei->flags = 0;
9201         ei->csum_bytes = 0;
9202         ei->index_cnt = (u64)-1;
9203         ei->dir_index = 0;
9204         ei->last_unlink_trans = 0;
9205         ei->last_log_commit = 0;
9206         ei->delayed_iput_count = 0;
9207
9208         spin_lock_init(&ei->lock);
9209         ei->outstanding_extents = 0;
9210         ei->reserved_extents = 0;
9211
9212         ei->runtime_flags = 0;
9213         ei->force_compress = BTRFS_COMPRESS_NONE;
9214
9215         ei->delayed_node = NULL;
9216
9217         ei->i_otime.tv_sec = 0;
9218         ei->i_otime.tv_nsec = 0;
9219
9220         inode = &ei->vfs_inode;
9221         extent_map_tree_init(&ei->extent_tree);
9222         extent_io_tree_init(&ei->io_tree, &inode->i_data);
9223         extent_io_tree_init(&ei->io_failure_tree, &inode->i_data);
9224         ei->io_tree.track_uptodate = 1;
9225         ei->io_failure_tree.track_uptodate = 1;
9226         atomic_set(&ei->sync_writers, 0);
9227         mutex_init(&ei->log_mutex);
9228         mutex_init(&ei->delalloc_mutex);
9229         btrfs_ordered_inode_tree_init(&ei->ordered_tree);
9230         INIT_LIST_HEAD(&ei->delalloc_inodes);
9231         INIT_LIST_HEAD(&ei->delayed_iput);
9232         RB_CLEAR_NODE(&ei->rb_node);
9233
9234         return inode;
9235 }
9236
9237 #ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
9238 void btrfs_test_destroy_inode(struct inode *inode)
9239 {
9240         btrfs_drop_extent_cache(inode, 0, (u64)-1, 0);
9241         kmem_cache_free(btrfs_inode_cachep, BTRFS_I(inode));
9242 }
9243 #endif
9244
9245 static void btrfs_i_callback(struct rcu_head *head)
9246 {
9247         struct inode *inode = container_of(head, struct inode, i_rcu);
9248         kmem_cache_free(btrfs_inode_cachep, BTRFS_I(inode));
9249 }
9250
9251 void btrfs_destroy_inode(struct inode *inode)
9252 {
9253         struct btrfs_ordered_extent *ordered;
9254         struct btrfs_root *root = BTRFS_I(inode)->root;
9255
9256         WARN_ON(!hlist_empty(&inode->i_dentry));
9257         WARN_ON(inode->i_data.nrpages);
9258         WARN_ON(BTRFS_I(inode)->outstanding_extents);
9259         WARN_ON(BTRFS_I(inode)->reserved_extents);
9260         WARN_ON(BTRFS_I(inode)->delalloc_bytes);
9261         WARN_ON(BTRFS_I(inode)->csum_bytes);
9262         WARN_ON(BTRFS_I(inode)->defrag_bytes);
9263
9264         /*
9265          * This can happen where we create an inode, but somebody else also
9266          * created the same inode and we need to destroy the one we already
9267          * created.
9268          */
9269         if (!root)
9270                 goto free;
9271
9272         if (test_bit(BTRFS_INODE_HAS_ORPHAN_ITEM,
9273                      &BTRFS_I(inode)->runtime_flags)) {
9274                 btrfs_info(root->fs_info, "inode %llu still on the orphan list",
9275                         btrfs_ino(inode));
9276                 atomic_dec(&root->orphan_inodes);
9277         }
9278
9279         while (1) {
9280                 ordered = btrfs_lookup_first_ordered_extent(inode, (u64)-1);
9281                 if (!ordered)
9282                         break;
9283                 else {
9284                         btrfs_err(root->fs_info, "found ordered extent %llu %llu on inode cleanup",
9285                                 ordered->file_offset, ordered->len);
9286                         btrfs_remove_ordered_extent(inode, ordered);
9287                         btrfs_put_ordered_extent(ordered);
9288                         btrfs_put_ordered_extent(ordered);
9289                 }
9290         }
9291         btrfs_qgroup_check_reserved_leak(inode);
9292         inode_tree_del(inode);
9293         btrfs_drop_extent_cache(inode, 0, (u64)-1, 0);
9294 free:
9295         call_rcu(&inode->i_rcu, btrfs_i_callback);
9296 }
9297
9298 int btrfs_drop_inode(struct inode *inode)
9299 {
9300         struct btrfs_root *root = BTRFS_I(inode)->root;
9301
9302         if (root == NULL)
9303                 return 1;
9304
9305         /* the snap/subvol tree is on deleting */
9306         if (btrfs_root_refs(&root->root_item) == 0)
9307                 return 1;
9308         else
9309                 return generic_drop_inode(inode);
9310 }
9311
9312 static void init_once(void *foo)
9313 {
9314         struct btrfs_inode *ei = (struct btrfs_inode *) foo;
9315
9316         inode_init_once(&ei->vfs_inode);
9317 }
9318
9319 void btrfs_destroy_cachep(void)
9320 {
9321         /*
9322          * Make sure all delayed rcu free inodes are flushed before we
9323          * destroy cache.
9324          */
9325         rcu_barrier();
9326         kmem_cache_destroy(btrfs_inode_cachep);
9327         kmem_cache_destroy(btrfs_trans_handle_cachep);
9328         kmem_cache_destroy(btrfs_transaction_cachep);
9329         kmem_cache_destroy(btrfs_path_cachep);
9330         kmem_cache_destroy(btrfs_free_space_cachep);
9331 }
9332
9333 int btrfs_init_cachep(void)
9334 {
9335         btrfs_inode_cachep = kmem_cache_create("btrfs_inode",
9336                         sizeof(struct btrfs_inode), 0,
9337                         SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD | SLAB_ACCOUNT,
9338                         init_once);
9339         if (!btrfs_inode_cachep)
9340                 goto fail;
9341
9342         btrfs_trans_handle_cachep = kmem_cache_create("btrfs_trans_handle",
9343                         sizeof(struct btrfs_trans_handle), 0,
9344                         SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD, NULL);
9345         if (!btrfs_trans_handle_cachep)
9346                 goto fail;
9347
9348         btrfs_transaction_cachep = kmem_cache_create("btrfs_transaction",
9349                         sizeof(struct btrfs_transaction), 0,
9350                         SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD, NULL);
9351         if (!btrfs_transaction_cachep)
9352                 goto fail;
9353
9354         btrfs_path_cachep = kmem_cache_create("btrfs_path",
9355                         sizeof(struct btrfs_path), 0,
9356                         SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD, NULL);
9357         if (!btrfs_path_cachep)
9358                 goto fail;
9359
9360         btrfs_free_space_cachep = kmem_cache_create("btrfs_free_space",
9361                         sizeof(struct btrfs_free_space), 0,
9362                         SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD, NULL);
9363         if (!btrfs_free_space_cachep)
9364                 goto fail;
9365
9366         return 0;
9367 fail:
9368         btrfs_destroy_cachep();
9369         return -ENOMEM;
9370 }
9371
9372 static int btrfs_getattr(struct vfsmount *mnt,
9373                          struct dentry *dentry, struct kstat *stat)
9374 {
9375         u64 delalloc_bytes;
9376         struct inode *inode = d_inode(dentry);
9377         u32 blocksize = inode->i_sb->s_blocksize;
9378
9379         generic_fillattr(inode, stat);
9380         stat->dev = BTRFS_I(inode)->root->anon_dev;
9381
9382         spin_lock(&BTRFS_I(inode)->lock);
9383         delalloc_bytes = BTRFS_I(inode)->delalloc_bytes;
9384         spin_unlock(&BTRFS_I(inode)->lock);
9385         stat->blocks = (ALIGN(inode_get_bytes(inode), blocksize) +
9386                         ALIGN(delalloc_bytes, blocksize)) >> 9;
9387         return 0;
9388 }
9389
9390 static int btrfs_rename(struct inode *old_dir, struct dentry *old_dentry,
9391                            struct inode *new_dir, struct dentry *new_dentry)
9392 {
9393         struct btrfs_trans_handle *trans;
9394         struct btrfs_root *root = BTRFS_I(old_dir)->root;
9395         struct btrfs_root *dest = BTRFS_I(new_dir)->root;
9396         struct inode *new_inode = d_inode(new_dentry);
9397         struct inode *old_inode = d_inode(old_dentry);
9398         u64 index = 0;
9399         u64 root_objectid;
9400         int ret;
9401         u64 old_ino = btrfs_ino(old_inode);
9402
9403         if (btrfs_ino(new_dir) == BTRFS_EMPTY_SUBVOL_DIR_OBJECTID)
9404                 return -EPERM;
9405
9406         /* we only allow rename subvolume link between subvolumes */
9407         if (old_ino != BTRFS_FIRST_FREE_OBJECTID && root != dest)
9408                 return -EXDEV;
9409
9410         if (old_ino == BTRFS_EMPTY_SUBVOL_DIR_OBJECTID ||
9411             (new_inode && btrfs_ino(new_inode) == BTRFS_FIRST_FREE_OBJECTID))
9412                 return -ENOTEMPTY;
9413
9414         if (S_ISDIR(old_inode->i_mode) && new_inode &&
9415             new_inode->i_size > BTRFS_EMPTY_DIR_SIZE)
9416                 return -ENOTEMPTY;
9417
9418
9419         /* check for collisions, even if the  name isn't there */
9420         ret = btrfs_check_dir_item_collision(dest, new_dir->i_ino,
9421                              new_dentry->d_name.name,
9422                              new_dentry->d_name.len);
9423
9424         if (ret) {
9425                 if (ret == -EEXIST) {
9426                         /* we shouldn't get
9427                          * eexist without a new_inode */
9428                         if (WARN_ON(!new_inode)) {
9429                                 return ret;
9430                         }
9431                 } else {
9432                         /* maybe -EOVERFLOW */
9433                         return ret;
9434                 }
9435         }
9436         ret = 0;
9437
9438         /*
9439          * we're using rename to replace one file with another.  Start IO on it
9440          * now so  we don't add too much work to the end of the transaction
9441          */
9442         if (new_inode && S_ISREG(old_inode->i_mode) && new_inode->i_size)
9443                 filemap_flush(old_inode->i_mapping);
9444
9445         /* close the racy window with snapshot create/destroy ioctl */
9446         if (old_ino == BTRFS_FIRST_FREE_OBJECTID)
9447                 down_read(&root->fs_info->subvol_sem);
9448         /*
9449          * We want to reserve the absolute worst case amount of items.  So if
9450          * both inodes are subvols and we need to unlink them then that would
9451          * require 4 item modifications, but if they are both normal inodes it
9452          * would require 5 item modifications, so we'll assume their normal
9453          * inodes.  So 5 * 2 is 10, plus 1 for the new link, so 11 total items
9454          * should cover the worst case number of items we'll modify.
9455          */
9456         trans = btrfs_start_transaction(root, 11);
9457         if (IS_ERR(trans)) {
9458                 ret = PTR_ERR(trans);
9459                 goto out_notrans;
9460         }
9461
9462         if (dest != root)
9463                 btrfs_record_root_in_trans(trans, dest);
9464
9465         ret = btrfs_set_inode_index(new_dir, &index);
9466         if (ret)
9467                 goto out_fail;
9468
9469         BTRFS_I(old_inode)->dir_index = 0ULL;
9470         if (unlikely(old_ino == BTRFS_FIRST_FREE_OBJECTID)) {
9471                 /* force full log commit if subvolume involved. */
9472                 btrfs_set_log_full_commit(root->fs_info, trans);
9473         } else {
9474                 ret = btrfs_insert_inode_ref(trans, dest,
9475                                              new_dentry->d_name.name,
9476                                              new_dentry->d_name.len,
9477                                              old_ino,
9478                                              btrfs_ino(new_dir), index);
9479                 if (ret)
9480                         goto out_fail;
9481                 /*
9482                  * this is an ugly little race, but the rename is required
9483                  * to make sure that if we crash, the inode is either at the
9484                  * old name or the new one.  pinning the log transaction lets
9485                  * us make sure we don't allow a log commit to come in after
9486                  * we unlink the name but before we add the new name back in.
9487                  */
9488                 btrfs_pin_log_trans(root);
9489         }
9490
9491         inode_inc_iversion(old_dir);
9492         inode_inc_iversion(new_dir);
9493         inode_inc_iversion(old_inode);
9494         old_dir->i_ctime = old_dir->i_mtime =
9495         new_dir->i_ctime = new_dir->i_mtime =
9496         old_inode->i_ctime = current_fs_time(old_dir->i_sb);
9497
9498         if (old_dentry->d_parent != new_dentry->d_parent)
9499                 btrfs_record_unlink_dir(trans, old_dir, old_inode, 1);
9500
9501         if (unlikely(old_ino == BTRFS_FIRST_FREE_OBJECTID)) {
9502                 root_objectid = BTRFS_I(old_inode)->root->root_key.objectid;
9503                 ret = btrfs_unlink_subvol(trans, root, old_dir, root_objectid,
9504                                         old_dentry->d_name.name,
9505                                         old_dentry->d_name.len);
9506         } else {
9507                 ret = __btrfs_unlink_inode(trans, root, old_dir,
9508                                         d_inode(old_dentry),
9509                                         old_dentry->d_name.name,
9510                                         old_dentry->d_name.len);
9511                 if (!ret)
9512                         ret = btrfs_update_inode(trans, root, old_inode);
9513         }
9514         if (ret) {
9515                 btrfs_abort_transaction(trans, root, ret);
9516                 goto out_fail;
9517         }
9518
9519         if (new_inode) {
9520                 inode_inc_iversion(new_inode);
9521                 new_inode->i_ctime = current_fs_time(new_inode->i_sb);
9522                 if (unlikely(btrfs_ino(new_inode) ==
9523                              BTRFS_EMPTY_SUBVOL_DIR_OBJECTID)) {
9524                         root_objectid = BTRFS_I(new_inode)->location.objectid;
9525                         ret = btrfs_unlink_subvol(trans, dest, new_dir,
9526                                                 root_objectid,
9527                                                 new_dentry->d_name.name,
9528                                                 new_dentry->d_name.len);
9529                         BUG_ON(new_inode->i_nlink == 0);
9530                 } else {
9531                         ret = btrfs_unlink_inode(trans, dest, new_dir,
9532                                                  d_inode(new_dentry),
9533                                                  new_dentry->d_name.name,
9534                                                  new_dentry->d_name.len);
9535                 }
9536                 if (!ret && new_inode->i_nlink == 0)
9537                         ret = btrfs_orphan_add(trans, d_inode(new_dentry));
9538                 if (ret) {
9539                         btrfs_abort_transaction(trans, root, ret);
9540                         goto out_fail;
9541                 }
9542         }
9543
9544         ret = btrfs_add_link(trans, new_dir, old_inode,
9545                              new_dentry->d_name.name,
9546                              new_dentry->d_name.len, 0, index);
9547         if (ret) {
9548                 btrfs_abort_transaction(trans, root, ret);
9549                 goto out_fail;
9550         }
9551
9552         if (old_inode->i_nlink == 1)
9553                 BTRFS_I(old_inode)->dir_index = index;
9554
9555         if (old_ino != BTRFS_FIRST_FREE_OBJECTID) {
9556                 struct dentry *parent = new_dentry->d_parent;
9557                 btrfs_log_new_name(trans, old_inode, old_dir, parent);
9558                 btrfs_end_log_trans(root);
9559         }
9560 out_fail:
9561         btrfs_end_transaction(trans, root);
9562 out_notrans:
9563         if (old_ino == BTRFS_FIRST_FREE_OBJECTID)
9564                 up_read(&root->fs_info->subvol_sem);
9565
9566         return ret;
9567 }
9568
9569 static int btrfs_rename2(struct inode *old_dir, struct dentry *old_dentry,
9570                          struct inode *new_dir, struct dentry *new_dentry,
9571                          unsigned int flags)
9572 {
9573         if (flags & ~RENAME_NOREPLACE)
9574                 return -EINVAL;
9575
9576         return btrfs_rename(old_dir, old_dentry, new_dir, new_dentry);
9577 }
9578
9579 static void btrfs_run_delalloc_work(struct btrfs_work *work)
9580 {
9581         struct btrfs_delalloc_work *delalloc_work;
9582         struct inode *inode;
9583
9584         delalloc_work = container_of(work, struct btrfs_delalloc_work,
9585                                      work);
9586         inode = delalloc_work->inode;
9587         filemap_flush(inode->i_mapping);
9588         if (test_bit(BTRFS_INODE_HAS_ASYNC_EXTENT,
9589                                 &BTRFS_I(inode)->runtime_flags))
9590                 filemap_flush(inode->i_mapping);
9591
9592         if (delalloc_work->delay_iput)
9593                 btrfs_add_delayed_iput(inode);
9594         else
9595                 iput(inode);
9596         complete(&delalloc_work->completion);
9597 }
9598
9599 struct btrfs_delalloc_work *btrfs_alloc_delalloc_work(struct inode *inode,
9600                                                     int delay_iput)
9601 {
9602         struct btrfs_delalloc_work *work;
9603
9604         work = kmalloc(sizeof(*work), GFP_NOFS);
9605         if (!work)
9606                 return NULL;
9607
9608         init_completion(&work->completion);
9609         INIT_LIST_HEAD(&work->list);
9610         work->inode = inode;
9611         work->delay_iput = delay_iput;
9612         WARN_ON_ONCE(!inode);
9613         btrfs_init_work(&work->work, btrfs_flush_delalloc_helper,
9614                         btrfs_run_delalloc_work, NULL, NULL);
9615
9616         return work;
9617 }
9618
9619 void btrfs_wait_and_free_delalloc_work(struct btrfs_delalloc_work *work)
9620 {
9621         wait_for_completion(&work->completion);
9622         kfree(work);
9623 }
9624
9625 /*
9626  * some fairly slow code that needs optimization. This walks the list
9627  * of all the inodes with pending delalloc and forces them to disk.
9628  */
9629 static int __start_delalloc_inodes(struct btrfs_root *root, int delay_iput,
9630                                    int nr)
9631 {
9632         struct btrfs_inode *binode;
9633         struct inode *inode;
9634         struct btrfs_delalloc_work *work, *next;
9635         struct list_head works;
9636         struct list_head splice;
9637         int ret = 0;
9638
9639         INIT_LIST_HEAD(&works);
9640         INIT_LIST_HEAD(&splice);
9641
9642         mutex_lock(&root->delalloc_mutex);
9643         spin_lock(&root->delalloc_lock);
9644         list_splice_init(&root->delalloc_inodes, &splice);
9645         while (!list_empty(&splice)) {
9646                 binode = list_entry(splice.next, struct btrfs_inode,
9647                                     delalloc_inodes);
9648
9649                 list_move_tail(&binode->delalloc_inodes,
9650                                &root->delalloc_inodes);
9651                 inode = igrab(&binode->vfs_inode);
9652                 if (!inode) {
9653                         cond_resched_lock(&root->delalloc_lock);
9654                         continue;
9655                 }
9656                 spin_unlock(&root->delalloc_lock);
9657
9658                 work = btrfs_alloc_delalloc_work(inode, delay_iput);
9659                 if (!work) {
9660                         if (delay_iput)
9661                                 btrfs_add_delayed_iput(inode);
9662                         else
9663                                 iput(inode);
9664                         ret = -ENOMEM;
9665                         goto out;
9666                 }
9667                 list_add_tail(&work->list, &works);
9668                 btrfs_queue_work(root->fs_info->flush_workers,
9669                                  &work->work);
9670                 ret++;
9671                 if (nr != -1 && ret >= nr)
9672                         goto out;
9673                 cond_resched();
9674                 spin_lock(&root->delalloc_lock);
9675         }
9676         spin_unlock(&root->delalloc_lock);
9677
9678 out:
9679         list_for_each_entry_safe(work, next, &works, list) {
9680                 list_del_init(&work->list);
9681                 btrfs_wait_and_free_delalloc_work(work);
9682         }
9683
9684         if (!list_empty_careful(&splice)) {
9685                 spin_lock(&root->delalloc_lock);
9686                 list_splice_tail(&splice, &root->delalloc_inodes);
9687                 spin_unlock(&root->delalloc_lock);
9688         }
9689         mutex_unlock(&root->delalloc_mutex);
9690         return ret;
9691 }
9692
9693 int btrfs_start_delalloc_inodes(struct btrfs_root *root, int delay_iput)
9694 {
9695         int ret;
9696
9697         if (test_bit(BTRFS_FS_STATE_ERROR, &root->fs_info->fs_state))
9698                 return -EROFS;
9699
9700         ret = __start_delalloc_inodes(root, delay_iput, -1);
9701         if (ret > 0)
9702                 ret = 0;
9703         /*
9704          * the filemap_flush will queue IO into the worker threads, but
9705          * we have to make sure the IO is actually started and that
9706          * ordered extents get created before we return
9707          */
9708         atomic_inc(&root->fs_info->async_submit_draining);
9709         while (atomic_read(&root->fs_info->nr_async_submits) ||
9710               atomic_read(&root->fs_info->async_delalloc_pages)) {
9711                 wait_event(root->fs_info->async_submit_wait,
9712                    (atomic_read(&root->fs_info->nr_async_submits) == 0 &&
9713                     atomic_read(&root->fs_info->async_delalloc_pages) == 0));
9714         }
9715         atomic_dec(&root->fs_info->async_submit_draining);
9716         return ret;
9717 }
9718
9719 int btrfs_start_delalloc_roots(struct btrfs_fs_info *fs_info, int delay_iput,
9720                                int nr)
9721 {
9722         struct btrfs_root *root;
9723         struct list_head splice;
9724         int ret;
9725
9726         if (test_bit(BTRFS_FS_STATE_ERROR, &fs_info->fs_state))
9727                 return -EROFS;
9728
9729         INIT_LIST_HEAD(&splice);
9730
9731         mutex_lock(&fs_info->delalloc_root_mutex);
9732         spin_lock(&fs_info->delalloc_root_lock);
9733         list_splice_init(&fs_info->delalloc_roots, &splice);
9734         while (!list_empty(&splice) && nr) {
9735                 root = list_first_entry(&splice, struct btrfs_root,
9736                                         delalloc_root);
9737                 root = btrfs_grab_fs_root(root);
9738                 BUG_ON(!root);
9739                 list_move_tail(&root->delalloc_root,
9740                                &fs_info->delalloc_roots);
9741                 spin_unlock(&fs_info->delalloc_root_lock);
9742
9743                 ret = __start_delalloc_inodes(root, delay_iput, nr);
9744                 btrfs_put_fs_root(root);
9745                 if (ret < 0)
9746                         goto out;
9747
9748                 if (nr != -1) {
9749                         nr -= ret;
9750                         WARN_ON(nr < 0);
9751                 }
9752                 spin_lock(&fs_info->delalloc_root_lock);
9753         }
9754         spin_unlock(&fs_info->delalloc_root_lock);
9755
9756         ret = 0;
9757         atomic_inc(&fs_info->async_submit_draining);
9758         while (atomic_read(&fs_info->nr_async_submits) ||
9759               atomic_read(&fs_info->async_delalloc_pages)) {
9760                 wait_event(fs_info->async_submit_wait,
9761                    (atomic_read(&fs_info->nr_async_submits) == 0 &&
9762                     atomic_read(&fs_info->async_delalloc_pages) == 0));
9763         }
9764         atomic_dec(&fs_info->async_submit_draining);
9765 out:
9766         if (!list_empty_careful(&splice)) {
9767                 spin_lock(&fs_info->delalloc_root_lock);
9768                 list_splice_tail(&splice, &fs_info->delalloc_roots);
9769                 spin_unlock(&fs_info->delalloc_root_lock);
9770         }
9771         mutex_unlock(&fs_info->delalloc_root_mutex);
9772         return ret;
9773 }
9774
9775 static int btrfs_symlink(struct inode *dir, struct dentry *dentry,
9776                          const char *symname)
9777 {
9778         struct btrfs_trans_handle *trans;
9779         struct btrfs_root *root = BTRFS_I(dir)->root;
9780         struct btrfs_path *path;
9781         struct btrfs_key key;
9782         struct inode *inode = NULL;
9783         int err;
9784         int drop_inode = 0;
9785         u64 objectid;
9786         u64 index = 0;
9787         int name_len;
9788         int datasize;
9789         unsigned long ptr;
9790         struct btrfs_file_extent_item *ei;
9791         struct extent_buffer *leaf;
9792
9793         name_len = strlen(symname);
9794         if (name_len > BTRFS_MAX_INLINE_DATA_SIZE(root))
9795                 return -ENAMETOOLONG;
9796
9797         /*
9798          * 2 items for inode item and ref
9799          * 2 items for dir items
9800          * 1 item for updating parent inode item
9801          * 1 item for the inline extent item
9802          * 1 item for xattr if selinux is on
9803          */
9804         trans = btrfs_start_transaction(root, 7);
9805         if (IS_ERR(trans))
9806                 return PTR_ERR(trans);
9807
9808         err = btrfs_find_free_ino(root, &objectid);
9809         if (err)
9810                 goto out_unlock;
9811
9812         inode = btrfs_new_inode(trans, root, dir, dentry->d_name.name,
9813                                 dentry->d_name.len, btrfs_ino(dir), objectid,
9814                                 S_IFLNK|S_IRWXUGO, &index);
9815         if (IS_ERR(inode)) {
9816                 err = PTR_ERR(inode);
9817                 goto out_unlock;
9818         }
9819
9820         /*
9821         * If the active LSM wants to access the inode during
9822         * d_instantiate it needs these. Smack checks to see
9823         * if the filesystem supports xattrs by looking at the
9824         * ops vector.
9825         */
9826         inode->i_fop = &btrfs_file_operations;
9827         inode->i_op = &btrfs_file_inode_operations;
9828         inode->i_mapping->a_ops = &btrfs_aops;
9829         BTRFS_I(inode)->io_tree.ops = &btrfs_extent_io_ops;
9830
9831         err = btrfs_init_inode_security(trans, inode, dir, &dentry->d_name);
9832         if (err)
9833                 goto out_unlock_inode;
9834
9835         path = btrfs_alloc_path();
9836         if (!path) {
9837                 err = -ENOMEM;
9838                 goto out_unlock_inode;
9839         }
9840         key.objectid = btrfs_ino(inode);
9841         key.offset = 0;
9842         key.type = BTRFS_EXTENT_DATA_KEY;
9843         datasize = btrfs_file_extent_calc_inline_size(name_len);
9844         err = btrfs_insert_empty_item(trans, root, path, &key,
9845                                       datasize);
9846         if (err) {
9847                 btrfs_free_path(path);
9848                 goto out_unlock_inode;
9849         }
9850         leaf = path->nodes[0];
9851         ei = btrfs_item_ptr(leaf, path->slots[0],
9852                             struct btrfs_file_extent_item);
9853         btrfs_set_file_extent_generation(leaf, ei, trans->transid);
9854         btrfs_set_file_extent_type(leaf, ei,
9855                                    BTRFS_FILE_EXTENT_INLINE);
9856         btrfs_set_file_extent_encryption(leaf, ei, 0);
9857         btrfs_set_file_extent_compression(leaf, ei, 0);
9858         btrfs_set_file_extent_other_encoding(leaf, ei, 0);
9859         btrfs_set_file_extent_ram_bytes(leaf, ei, name_len);
9860
9861         ptr = btrfs_file_extent_inline_start(ei);
9862         write_extent_buffer(leaf, symname, ptr, name_len);
9863         btrfs_mark_buffer_dirty(leaf);
9864         btrfs_free_path(path);
9865
9866         inode->i_op = &btrfs_symlink_inode_operations;
9867         inode_nohighmem(inode);
9868         inode->i_mapping->a_ops = &btrfs_symlink_aops;
9869         inode_set_bytes(inode, name_len);
9870         btrfs_i_size_write(inode, name_len);
9871         err = btrfs_update_inode(trans, root, inode);
9872         /*
9873          * Last step, add directory indexes for our symlink inode. This is the
9874          * last step to avoid extra cleanup of these indexes if an error happens
9875          * elsewhere above.
9876          */
9877         if (!err)
9878                 err = btrfs_add_nondir(trans, dir, dentry, inode, 0, index);
9879         if (err) {
9880                 drop_inode = 1;
9881                 goto out_unlock_inode;
9882         }
9883
9884         unlock_new_inode(inode);
9885         d_instantiate(dentry, inode);
9886
9887 out_unlock:
9888         btrfs_end_transaction(trans, root);
9889         if (drop_inode) {
9890                 inode_dec_link_count(inode);
9891                 iput(inode);
9892         }
9893         btrfs_btree_balance_dirty(root);
9894         return err;
9895
9896 out_unlock_inode:
9897         drop_inode = 1;
9898         unlock_new_inode(inode);
9899         goto out_unlock;
9900 }
9901
9902 static int __btrfs_prealloc_file_range(struct inode *inode, int mode,
9903                                        u64 start, u64 num_bytes, u64 min_size,
9904                                        loff_t actual_len, u64 *alloc_hint,
9905                                        struct btrfs_trans_handle *trans)
9906 {
9907         struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
9908         struct extent_map *em;
9909         struct btrfs_root *root = BTRFS_I(inode)->root;
9910         struct btrfs_key ins;
9911         u64 cur_offset = start;
9912         u64 i_size;
9913         u64 cur_bytes;
9914         u64 last_alloc = (u64)-1;
9915         int ret = 0;
9916         bool own_trans = true;
9917
9918         if (trans)
9919                 own_trans = false;
9920         while (num_bytes > 0) {
9921                 if (own_trans) {
9922                         trans = btrfs_start_transaction(root, 3);
9923                         if (IS_ERR(trans)) {
9924                                 ret = PTR_ERR(trans);
9925                                 break;
9926                         }
9927                 }
9928
9929                 cur_bytes = min_t(u64, num_bytes, SZ_256M);
9930                 cur_bytes = max(cur_bytes, min_size);
9931                 /*
9932                  * If we are severely fragmented we could end up with really
9933                  * small allocations, so if the allocator is returning small
9934                  * chunks lets make its job easier by only searching for those
9935                  * sized chunks.
9936                  */
9937                 cur_bytes = min(cur_bytes, last_alloc);
9938                 ret = btrfs_reserve_extent(root, cur_bytes, min_size, 0,
9939                                            *alloc_hint, &ins, 1, 0);
9940                 if (ret) {
9941                         if (own_trans)
9942                                 btrfs_end_transaction(trans, root);
9943                         break;
9944                 }
9945
9946                 last_alloc = ins.offset;
9947                 ret = insert_reserved_file_extent(trans, inode,
9948                                                   cur_offset, ins.objectid,
9949                                                   ins.offset, ins.offset,
9950                                                   ins.offset, 0, 0, 0,
9951                                                   BTRFS_FILE_EXTENT_PREALLOC);
9952                 if (ret) {
9953                         btrfs_free_reserved_extent(root, ins.objectid,
9954                                                    ins.offset, 0);
9955                         btrfs_abort_transaction(trans, root, ret);
9956                         if (own_trans)
9957                                 btrfs_end_transaction(trans, root);
9958                         break;
9959                 }
9960
9961                 btrfs_drop_extent_cache(inode, cur_offset,
9962                                         cur_offset + ins.offset -1, 0);
9963
9964                 em = alloc_extent_map();
9965                 if (!em) {
9966                         set_bit(BTRFS_INODE_NEEDS_FULL_SYNC,
9967                                 &BTRFS_I(inode)->runtime_flags);
9968                         goto next;
9969                 }
9970
9971                 em->start = cur_offset;
9972                 em->orig_start = cur_offset;
9973                 em->len = ins.offset;
9974                 em->block_start = ins.objectid;
9975                 em->block_len = ins.offset;
9976                 em->orig_block_len = ins.offset;
9977                 em->ram_bytes = ins.offset;
9978                 em->bdev = root->fs_info->fs_devices->latest_bdev;
9979                 set_bit(EXTENT_FLAG_PREALLOC, &em->flags);
9980                 em->generation = trans->transid;
9981
9982                 while (1) {
9983                         write_lock(&em_tree->lock);
9984                         ret = add_extent_mapping(em_tree, em, 1);
9985                         write_unlock(&em_tree->lock);
9986                         if (ret != -EEXIST)
9987                                 break;
9988                         btrfs_drop_extent_cache(inode, cur_offset,
9989                                                 cur_offset + ins.offset - 1,
9990                                                 0);
9991                 }
9992                 free_extent_map(em);
9993 next:
9994                 num_bytes -= ins.offset;
9995                 cur_offset += ins.offset;
9996                 *alloc_hint = ins.objectid + ins.offset;
9997
9998                 inode_inc_iversion(inode);
9999                 inode->i_ctime = current_fs_time(inode->i_sb);
10000                 BTRFS_I(inode)->flags |= BTRFS_INODE_PREALLOC;
10001                 if (!(mode & FALLOC_FL_KEEP_SIZE) &&
10002                     (actual_len > inode->i_size) &&
10003                     (cur_offset > inode->i_size)) {
10004                         if (cur_offset > actual_len)
10005                                 i_size = actual_len;
10006                         else
10007                                 i_size = cur_offset;
10008                         i_size_write(inode, i_size);
10009                         btrfs_ordered_update_i_size(inode, i_size, NULL);
10010                 }
10011
10012                 ret = btrfs_update_inode(trans, root, inode);
10013
10014                 if (ret) {
10015                         btrfs_abort_transaction(trans, root, ret);
10016                         if (own_trans)
10017                                 btrfs_end_transaction(trans, root);
10018                         break;
10019                 }
10020
10021                 if (own_trans)
10022                         btrfs_end_transaction(trans, root);
10023         }
10024         return ret;
10025 }
10026
10027 int btrfs_prealloc_file_range(struct inode *inode, int mode,
10028                               u64 start, u64 num_bytes, u64 min_size,
10029                               loff_t actual_len, u64 *alloc_hint)
10030 {
10031         return __btrfs_prealloc_file_range(inode, mode, start, num_bytes,
10032                                            min_size, actual_len, alloc_hint,
10033                                            NULL);
10034 }
10035
10036 int btrfs_prealloc_file_range_trans(struct inode *inode,
10037                                     struct btrfs_trans_handle *trans, int mode,
10038                                     u64 start, u64 num_bytes, u64 min_size,
10039                                     loff_t actual_len, u64 *alloc_hint)
10040 {
10041         return __btrfs_prealloc_file_range(inode, mode, start, num_bytes,
10042                                            min_size, actual_len, alloc_hint, trans);
10043 }
10044
10045 static int btrfs_set_page_dirty(struct page *page)
10046 {
10047         return __set_page_dirty_nobuffers(page);
10048 }
10049
10050 static int btrfs_permission(struct inode *inode, int mask)
10051 {
10052         struct btrfs_root *root = BTRFS_I(inode)->root;
10053         umode_t mode = inode->i_mode;
10054
10055         if (mask & MAY_WRITE &&
10056             (S_ISREG(mode) || S_ISDIR(mode) || S_ISLNK(mode))) {
10057                 if (btrfs_root_readonly(root))
10058                         return -EROFS;
10059                 if (BTRFS_I(inode)->flags & BTRFS_INODE_READONLY)
10060                         return -EACCES;
10061         }
10062         return generic_permission(inode, mask);
10063 }
10064
10065 static int btrfs_tmpfile(struct inode *dir, struct dentry *dentry, umode_t mode)
10066 {
10067         struct btrfs_trans_handle *trans;
10068         struct btrfs_root *root = BTRFS_I(dir)->root;
10069         struct inode *inode = NULL;
10070         u64 objectid;
10071         u64 index;
10072         int ret = 0;
10073
10074         /*
10075          * 5 units required for adding orphan entry
10076          */
10077         trans = btrfs_start_transaction(root, 5);
10078         if (IS_ERR(trans))
10079                 return PTR_ERR(trans);
10080
10081         ret = btrfs_find_free_ino(root, &objectid);
10082         if (ret)
10083                 goto out;
10084
10085         inode = btrfs_new_inode(trans, root, dir, NULL, 0,
10086                                 btrfs_ino(dir), objectid, mode, &index);
10087         if (IS_ERR(inode)) {
10088                 ret = PTR_ERR(inode);
10089                 inode = NULL;
10090                 goto out;
10091         }
10092
10093         inode->i_fop = &btrfs_file_operations;
10094         inode->i_op = &btrfs_file_inode_operations;
10095
10096         inode->i_mapping->a_ops = &btrfs_aops;
10097         BTRFS_I(inode)->io_tree.ops = &btrfs_extent_io_ops;
10098
10099         ret = btrfs_init_inode_security(trans, inode, dir, NULL);
10100         if (ret)
10101                 goto out_inode;
10102
10103         ret = btrfs_update_inode(trans, root, inode);
10104         if (ret)
10105                 goto out_inode;
10106         ret = btrfs_orphan_add(trans, inode);
10107         if (ret)
10108                 goto out_inode;
10109
10110         /*
10111          * We set number of links to 0 in btrfs_new_inode(), and here we set
10112          * it to 1 because d_tmpfile() will issue a warning if the count is 0,
10113          * through:
10114          *
10115          *    d_tmpfile() -> inode_dec_link_count() -> drop_nlink()
10116          */
10117         set_nlink(inode, 1);
10118         unlock_new_inode(inode);
10119         d_tmpfile(dentry, inode);
10120         mark_inode_dirty(inode);
10121
10122 out:
10123         btrfs_end_transaction(trans, root);
10124         if (ret)
10125                 iput(inode);
10126         btrfs_balance_delayed_items(root);
10127         btrfs_btree_balance_dirty(root);
10128         return ret;
10129
10130 out_inode:
10131         unlock_new_inode(inode);
10132         goto out;
10133
10134 }
10135
10136 /* Inspired by filemap_check_errors() */
10137 int btrfs_inode_check_errors(struct inode *inode)
10138 {
10139         int ret = 0;
10140
10141         if (test_bit(AS_ENOSPC, &inode->i_mapping->flags) &&
10142             test_and_clear_bit(AS_ENOSPC, &inode->i_mapping->flags))
10143                 ret = -ENOSPC;
10144         if (test_bit(AS_EIO, &inode->i_mapping->flags) &&
10145             test_and_clear_bit(AS_EIO, &inode->i_mapping->flags))
10146                 ret = -EIO;
10147
10148         return ret;
10149 }
10150
10151 static const struct inode_operations btrfs_dir_inode_operations = {
10152         .getattr        = btrfs_getattr,
10153         .lookup         = btrfs_lookup,
10154         .create         = btrfs_create,
10155         .unlink         = btrfs_unlink,
10156         .link           = btrfs_link,
10157         .mkdir          = btrfs_mkdir,
10158         .rmdir          = btrfs_rmdir,
10159         .rename2        = btrfs_rename2,
10160         .symlink        = btrfs_symlink,
10161         .setattr        = btrfs_setattr,
10162         .mknod          = btrfs_mknod,
10163         .setxattr       = btrfs_setxattr,
10164         .getxattr       = generic_getxattr,
10165         .listxattr      = btrfs_listxattr,
10166         .removexattr    = btrfs_removexattr,
10167         .permission     = btrfs_permission,
10168         .get_acl        = btrfs_get_acl,
10169         .set_acl        = btrfs_set_acl,
10170         .update_time    = btrfs_update_time,
10171         .tmpfile        = btrfs_tmpfile,
10172 };
10173 static const struct inode_operations btrfs_dir_ro_inode_operations = {
10174         .lookup         = btrfs_lookup,
10175         .permission     = btrfs_permission,
10176         .get_acl        = btrfs_get_acl,
10177         .set_acl        = btrfs_set_acl,
10178         .update_time    = btrfs_update_time,
10179 };
10180
10181 static const struct file_operations btrfs_dir_file_operations = {
10182         .llseek         = generic_file_llseek,
10183         .read           = generic_read_dir,
10184         .iterate        = btrfs_real_readdir,
10185         .unlocked_ioctl = btrfs_ioctl,
10186 #ifdef CONFIG_COMPAT
10187         .compat_ioctl   = btrfs_ioctl,
10188 #endif
10189         .release        = btrfs_release_file,
10190         .fsync          = btrfs_sync_file,
10191 };
10192
10193 static const struct extent_io_ops btrfs_extent_io_ops = {
10194         .fill_delalloc = run_delalloc_range,
10195         .submit_bio_hook = btrfs_submit_bio_hook,
10196         .merge_bio_hook = btrfs_merge_bio_hook,
10197         .readpage_end_io_hook = btrfs_readpage_end_io_hook,
10198         .writepage_end_io_hook = btrfs_writepage_end_io_hook,
10199         .writepage_start_hook = btrfs_writepage_start_hook,
10200         .set_bit_hook = btrfs_set_bit_hook,
10201         .clear_bit_hook = btrfs_clear_bit_hook,
10202         .merge_extent_hook = btrfs_merge_extent_hook,
10203         .split_extent_hook = btrfs_split_extent_hook,
10204 };
10205
10206 /*
10207  * btrfs doesn't support the bmap operation because swapfiles
10208  * use bmap to make a mapping of extents in the file.  They assume
10209  * these extents won't change over the life of the file and they
10210  * use the bmap result to do IO directly to the drive.
10211  *
10212  * the btrfs bmap call would return logical addresses that aren't
10213  * suitable for IO and they also will change frequently as COW
10214  * operations happen.  So, swapfile + btrfs == corruption.
10215  *
10216  * For now we're avoiding this by dropping bmap.
10217  */
10218 static const struct address_space_operations btrfs_aops = {
10219         .readpage       = btrfs_readpage,
10220         .writepage      = btrfs_writepage,
10221         .writepages     = btrfs_writepages,
10222         .readpages      = btrfs_readpages,
10223         .direct_IO      = btrfs_direct_IO,
10224         .invalidatepage = btrfs_invalidatepage,
10225         .releasepage    = btrfs_releasepage,
10226         .set_page_dirty = btrfs_set_page_dirty,
10227         .error_remove_page = generic_error_remove_page,
10228 };
10229
10230 static const struct address_space_operations btrfs_symlink_aops = {
10231         .readpage       = btrfs_readpage,
10232         .writepage      = btrfs_writepage,
10233         .invalidatepage = btrfs_invalidatepage,
10234         .releasepage    = btrfs_releasepage,
10235 };
10236
10237 static const struct inode_operations btrfs_file_inode_operations = {
10238         .getattr        = btrfs_getattr,
10239         .setattr        = btrfs_setattr,
10240         .setxattr       = btrfs_setxattr,
10241         .getxattr       = generic_getxattr,
10242         .listxattr      = btrfs_listxattr,
10243         .removexattr    = btrfs_removexattr,
10244         .permission     = btrfs_permission,
10245         .fiemap         = btrfs_fiemap,
10246         .get_acl        = btrfs_get_acl,
10247         .set_acl        = btrfs_set_acl,
10248         .update_time    = btrfs_update_time,
10249 };
10250 static const struct inode_operations btrfs_special_inode_operations = {
10251         .getattr        = btrfs_getattr,
10252         .setattr        = btrfs_setattr,
10253         .permission     = btrfs_permission,
10254         .setxattr       = btrfs_setxattr,
10255         .getxattr       = generic_getxattr,
10256         .listxattr      = btrfs_listxattr,
10257         .removexattr    = btrfs_removexattr,
10258         .get_acl        = btrfs_get_acl,
10259         .set_acl        = btrfs_set_acl,
10260         .update_time    = btrfs_update_time,
10261 };
10262 static const struct inode_operations btrfs_symlink_inode_operations = {
10263         .readlink       = generic_readlink,
10264         .get_link       = page_get_link,
10265         .getattr        = btrfs_getattr,
10266         .setattr        = btrfs_setattr,
10267         .permission     = btrfs_permission,
10268         .setxattr       = btrfs_setxattr,
10269         .getxattr       = generic_getxattr,
10270         .listxattr      = btrfs_listxattr,
10271         .removexattr    = btrfs_removexattr,
10272         .update_time    = btrfs_update_time,
10273 };
10274
10275 const struct dentry_operations btrfs_dentry_operations = {
10276         .d_delete       = btrfs_dentry_delete,
10277         .d_release      = btrfs_dentry_release,
10278 };