fs/btrfs/inode.c

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