fs/btrfs/file-item.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Copyright (C) 2007 Oracle.  All rights reserved.
   4  */
   5
   6 #include <linux/bio.h>
   7 #include <linux/slab.h>
   8 #include <linux/pagemap.h>
   9 #include <linux/highmem.h>
  10 #include <linux/sched/mm.h>
  11 #include <crypto/hash.h>
  12 #include "messages.h"
  13 #include "ctree.h"
  14 #include "disk-io.h"
  15 #include "transaction.h"
  16 #include "bio.h"
  17 #include "compression.h"
  18 #include "fs.h"
  19 #include "accessors.h"
  20 #include "file-item.h"
  21
  22 #define __MAX_CSUM_ITEMS(r, size) ((unsigned long)(((BTRFS_LEAF_DATA_SIZE(r) - \
  23                                    sizeof(struct btrfs_item) * 2) / \
  24                                   size) - 1))
  25
  26 #define MAX_CSUM_ITEMS(r, size) (min_t(u32, __MAX_CSUM_ITEMS(r, size), \
  27                                        PAGE_SIZE))
  28
  29 /*
  30  * Set inode's size according to filesystem options.
  31  *
  32  * @inode:      inode we want to update the disk_i_size for
  33  * @new_i_size: i_size we want to set to, 0 if we use i_size
  34  *
  35  * With NO_HOLES set this simply sets the disk_is_size to whatever i_size_read()
  36  * returns as it is perfectly fine with a file that has holes without hole file
  37  * extent items.
  38  *
  39  * However without NO_HOLES we need to only return the area that is contiguous
  40  * from the 0 offset of the file.  Otherwise we could end up adjust i_size up
  41  * to an extent that has a gap in between.
  42  *
  43  * Finally new_i_size should only be set in the case of truncate where we're not
  44  * ready to use i_size_read() as the limiter yet.
  45  */
  46 void btrfs_inode_safe_disk_i_size_write(struct btrfs_inode *inode, u64 new_i_size)
  47 {
  48         struct btrfs_fs_info *fs_info = inode->root->fs_info;
  49         u64 start, end, i_size;
  50         int ret;
  51
  52         spin_lock(&inode->lock);
  53         i_size = new_i_size ?: i_size_read(&inode->vfs_inode);
  54         if (btrfs_fs_incompat(fs_info, NO_HOLES)) {
  55                 inode->disk_i_size = i_size;
  56                 goto out_unlock;
  57         }
  58
  59         ret = find_contiguous_extent_bit(inode->file_extent_tree, 0, &start,
  60                                          &end, EXTENT_DIRTY);
  61         if (!ret && start == 0)
  62                 i_size = min(i_size, end + 1);
  63         else
  64                 i_size = 0;
  65         inode->disk_i_size = i_size;
  66 out_unlock:
  67         spin_unlock(&inode->lock);
  68 }
  69
  70 /*
  71  * Mark range within a file as having a new extent inserted.
  72  *
  73  * @inode: inode being modified
  74  * @start: start file offset of the file extent we've inserted
  75  * @len:   logical length of the file extent item
  76  *
  77  * Call when we are inserting a new file extent where there was none before.
  78  * Does not need to call this in the case where we're replacing an existing file
  79  * extent, however if not sure it's fine to call this multiple times.
  80  *
  81  * The start and len must match the file extent item, so thus must be sectorsize
  82  * aligned.
  83  */
  84 int btrfs_inode_set_file_extent_range(struct btrfs_inode *inode, u64 start,
  85                                       u64 len)
  86 {
  87         if (len == 0)
  88                 return 0;
  89
  90         ASSERT(IS_ALIGNED(start + len, inode->root->fs_info->sectorsize));
  91
  92         if (btrfs_fs_incompat(inode->root->fs_info, NO_HOLES))
  93                 return 0;
  94         return set_extent_bit(inode->file_extent_tree, start, start + len - 1,
  95                               EXTENT_DIRTY, NULL);
  96 }
  97
  98 /*
  99  * Mark an inode range as not having a backing extent.
 100  *
 101  * @inode: inode being modified
 102  * @start: start file offset of the file extent we've inserted
 103  * @len:   logical length of the file extent item
 104  *
 105  * Called when we drop a file extent, for example when we truncate.  Doesn't
 106  * need to be called for cases where we're replacing a file extent, like when
 107  * we've COWed a file extent.
 108  *
 109  * The start and len must match the file extent item, so thus must be sectorsize
 110  * aligned.
 111  */
 112 int btrfs_inode_clear_file_extent_range(struct btrfs_inode *inode, u64 start,
 113                                         u64 len)
 114 {
 115         if (len == 0)
 116                 return 0;
 117
 118         ASSERT(IS_ALIGNED(start + len, inode->root->fs_info->sectorsize) ||
 119                len == (u64)-1);
 120
 121         if (btrfs_fs_incompat(inode->root->fs_info, NO_HOLES))
 122                 return 0;
 123         return clear_extent_bit(inode->file_extent_tree, start,
 124                                 start + len - 1, EXTENT_DIRTY, NULL);
 125 }
 126
 127 static size_t bytes_to_csum_size(const struct btrfs_fs_info *fs_info, u32 bytes)
 128 {
 129         ASSERT(IS_ALIGNED(bytes, fs_info->sectorsize));
 130
 131         return (bytes >> fs_info->sectorsize_bits) * fs_info->csum_size;
 132 }
 133
 134 static size_t csum_size_to_bytes(const struct btrfs_fs_info *fs_info, u32 csum_size)
 135 {
 136         ASSERT(IS_ALIGNED(csum_size, fs_info->csum_size));
 137
 138         return (csum_size / fs_info->csum_size) << fs_info->sectorsize_bits;
 139 }
 140
 141 static inline u32 max_ordered_sum_bytes(const struct btrfs_fs_info *fs_info)
 142 {
 143         u32 max_csum_size = round_down(PAGE_SIZE - sizeof(struct btrfs_ordered_sum),
 144                                        fs_info->csum_size);
 145
 146         return csum_size_to_bytes(fs_info, max_csum_size);
 147 }
 148
 149 /*
 150  * Calculate the total size needed to allocate for an ordered sum structure
 151  * spanning @bytes in the file.
 152  */
 153 static int btrfs_ordered_sum_size(struct btrfs_fs_info *fs_info, unsigned long bytes)
 154 {
 155         return sizeof(struct btrfs_ordered_sum) + bytes_to_csum_size(fs_info, bytes);
 156 }
 157
 158 int btrfs_insert_hole_extent(struct btrfs_trans_handle *trans,
 159                              struct btrfs_root *root,
 160                              u64 objectid, u64 pos, u64 num_bytes)
 161 {
 162         int ret = 0;
 163         struct btrfs_file_extent_item *item;
 164         struct btrfs_key file_key;
 165         struct btrfs_path *path;
 166         struct extent_buffer *leaf;
 167
 168         path = btrfs_alloc_path();
 169         if (!path)
 170                 return -ENOMEM;
 171         file_key.objectid = objectid;
 172         file_key.offset = pos;
 173         file_key.type = BTRFS_EXTENT_DATA_KEY;
 174
 175         ret = btrfs_insert_empty_item(trans, root, path, &file_key,
 176                                       sizeof(*item));
 177         if (ret < 0)
 178                 goto out;
 179         leaf = path->nodes[0];
 180         item = btrfs_item_ptr(leaf, path->slots[0],
 181                               struct btrfs_file_extent_item);
 182         btrfs_set_file_extent_disk_bytenr(leaf, item, 0);
 183         btrfs_set_file_extent_disk_num_bytes(leaf, item, 0);
 184         btrfs_set_file_extent_offset(leaf, item, 0);
 185         btrfs_set_file_extent_num_bytes(leaf, item, num_bytes);
 186         btrfs_set_file_extent_ram_bytes(leaf, item, num_bytes);
 187         btrfs_set_file_extent_generation(leaf, item, trans->transid);
 188         btrfs_set_file_extent_type(leaf, item, BTRFS_FILE_EXTENT_REG);
 189         btrfs_set_file_extent_compression(leaf, item, 0);
 190         btrfs_set_file_extent_encryption(leaf, item, 0);
 191         btrfs_set_file_extent_other_encoding(leaf, item, 0);
 192
 193         btrfs_mark_buffer_dirty(trans, leaf);
 194 out:
 195         btrfs_free_path(path);
 196         return ret;
 197 }
 198
 199 static struct btrfs_csum_item *
 200 btrfs_lookup_csum(struct btrfs_trans_handle *trans,
 201                   struct btrfs_root *root,
 202                   struct btrfs_path *path,
 203                   u64 bytenr, int cow)
 204 {
 205         struct btrfs_fs_info *fs_info = root->fs_info;
 206         int ret;
 207         struct btrfs_key file_key;
 208         struct btrfs_key found_key;
 209         struct btrfs_csum_item *item;
 210         struct extent_buffer *leaf;
 211         u64 csum_offset = 0;
 212         const u32 csum_size = fs_info->csum_size;
 213         int csums_in_item;
 214
 215         file_key.objectid = BTRFS_EXTENT_CSUM_OBJECTID;
 216         file_key.offset = bytenr;
 217         file_key.type = BTRFS_EXTENT_CSUM_KEY;
 218         ret = btrfs_search_slot(trans, root, &file_key, path, 0, cow);
 219         if (ret < 0)
 220                 goto fail;
 221         leaf = path->nodes[0];
 222         if (ret > 0) {
 223                 ret = 1;
 224                 if (path->slots[0] == 0)
 225                         goto fail;
 226                 path->slots[0]--;
 227                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
 228                 if (found_key.type != BTRFS_EXTENT_CSUM_KEY)
 229                         goto fail;
 230
 231                 csum_offset = (bytenr - found_key.offset) >>
 232                                 fs_info->sectorsize_bits;
 233                 csums_in_item = btrfs_item_size(leaf, path->slots[0]);
 234                 csums_in_item /= csum_size;
 235
 236                 if (csum_offset == csums_in_item) {
 237                         ret = -EFBIG;
 238                         goto fail;
 239                 } else if (csum_offset > csums_in_item) {
 240                         goto fail;
 241                 }
 242         }
 243         item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_csum_item);
 244         item = (struct btrfs_csum_item *)((unsigned char *)item +
 245                                           csum_offset * csum_size);
 246         return item;
 247 fail:
 248         if (ret > 0)
 249                 ret = -ENOENT;
 250         return ERR_PTR(ret);
 251 }
 252
 253 int btrfs_lookup_file_extent(struct btrfs_trans_handle *trans,
 254                              struct btrfs_root *root,
 255                              struct btrfs_path *path, u64 objectid,
 256                              u64 offset, int mod)
 257 {
 258         struct btrfs_key file_key;
 259         int ins_len = mod < 0 ? -1 : 0;
 260         int cow = mod != 0;
 261
 262         file_key.objectid = objectid;
 263         file_key.offset = offset;
 264         file_key.type = BTRFS_EXTENT_DATA_KEY;
 265
 266         return btrfs_search_slot(trans, root, &file_key, path, ins_len, cow);
 267 }
 268
 269 /*
 270  * Find checksums for logical bytenr range [disk_bytenr, disk_bytenr + len) and
 271  * store the result to @dst.
 272  *
 273  * Return >0 for the number of sectors we found.
 274  * Return 0 for the range [disk_bytenr, disk_bytenr + sectorsize) has no csum
 275  * for it. Caller may want to try next sector until one range is hit.
 276  * Return <0 for fatal error.
 277  */
 278 static int search_csum_tree(struct btrfs_fs_info *fs_info,
 279                             struct btrfs_path *path, u64 disk_bytenr,
 280                             u64 len, u8 *dst)
 281 {
 282         struct btrfs_root *csum_root;
 283         struct btrfs_csum_item *item = NULL;
 284         struct btrfs_key key;
 285         const u32 sectorsize = fs_info->sectorsize;
 286         const u32 csum_size = fs_info->csum_size;
 287         u32 itemsize;
 288         int ret;
 289         u64 csum_start;
 290         u64 csum_len;
 291
 292         ASSERT(IS_ALIGNED(disk_bytenr, sectorsize) &&
 293                IS_ALIGNED(len, sectorsize));
 294
 295         /* Check if the current csum item covers disk_bytenr */
 296         if (path->nodes[0]) {
 297                 item = btrfs_item_ptr(path->nodes[0], path->slots[0],
 298                                       struct btrfs_csum_item);
 299                 btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
 300                 itemsize = btrfs_item_size(path->nodes[0], path->slots[0]);
 301
 302                 csum_start = key.offset;
 303                 csum_len = (itemsize / csum_size) * sectorsize;
 304
 305                 if (in_range(disk_bytenr, csum_start, csum_len))
 306                         goto found;
 307         }
 308
 309         /* Current item doesn't contain the desired range, search again */
 310         btrfs_release_path(path);
 311         csum_root = btrfs_csum_root(fs_info, disk_bytenr);
 312         item = btrfs_lookup_csum(NULL, csum_root, path, disk_bytenr, 0);
 313         if (IS_ERR(item)) {
 314                 ret = PTR_ERR(item);
 315                 goto out;
 316         }
 317         btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
 318         itemsize = btrfs_item_size(path->nodes[0], path->slots[0]);
 319
 320         csum_start = key.offset;
 321         csum_len = (itemsize / csum_size) * sectorsize;
 322         ASSERT(in_range(disk_bytenr, csum_start, csum_len));
 323
 324 found:
 325         ret = (min(csum_start + csum_len, disk_bytenr + len) -
 326                    disk_bytenr) >> fs_info->sectorsize_bits;
 327         read_extent_buffer(path->nodes[0], dst, (unsigned long)item,
 328                         ret * csum_size);
 329 out:
 330         if (ret == -ENOENT || ret == -EFBIG)
 331                 ret = 0;
 332         return ret;
 333 }
 334
 335 /*
 336  * Lookup the checksum for the read bio in csum tree.
 337  *
 338  * Return: BLK_STS_RESOURCE if allocating memory fails, BLK_STS_OK otherwise.
 339  */
 340 blk_status_t btrfs_lookup_bio_sums(struct btrfs_bio *bbio)
 341 {
 342         struct btrfs_inode *inode = bbio->inode;
 343         struct btrfs_fs_info *fs_info = inode->root->fs_info;
 344         struct bio *bio = &bbio->bio;
 345         struct btrfs_path *path;
 346         const u32 sectorsize = fs_info->sectorsize;
 347         const u32 csum_size = fs_info->csum_size;
 348         u32 orig_len = bio->bi_iter.bi_size;
 349         u64 orig_disk_bytenr = bio->bi_iter.bi_sector << SECTOR_SHIFT;
 350         const unsigned int nblocks = orig_len >> fs_info->sectorsize_bits;
 351         blk_status_t ret = BLK_STS_OK;
 352         u32 bio_offset = 0;
 353
 354         if ((inode->flags & BTRFS_INODE_NODATASUM) ||
 355             test_bit(BTRFS_FS_STATE_NO_CSUMS, &fs_info->fs_state))
 356                 return BLK_STS_OK;
 357
 358         /*
 359          * This function is only called for read bio.
 360          *
 361          * This means two things:
 362          * - All our csums should only be in csum tree
 363          *   No ordered extents csums, as ordered extents are only for write
 364          *   path.
 365          * - No need to bother any other info from bvec
 366          *   Since we're looking up csums, the only important info is the
 367          *   disk_bytenr and the length, which can be extracted from bi_iter
 368          *   directly.
 369          */
 370         ASSERT(bio_op(bio) == REQ_OP_READ);
 371         path = btrfs_alloc_path();
 372         if (!path)
 373                 return BLK_STS_RESOURCE;
 374
 375         if (nblocks * csum_size > BTRFS_BIO_INLINE_CSUM_SIZE) {
 376                 bbio->csum = kmalloc_array(nblocks, csum_size, GFP_NOFS);
 377                 if (!bbio->csum) {
 378                         btrfs_free_path(path);
 379                         return BLK_STS_RESOURCE;
 380                 }
 381         } else {
 382                 bbio->csum = bbio->csum_inline;
 383         }
 384
 385         /*
 386          * If requested number of sectors is larger than one leaf can contain,
 387          * kick the readahead for csum tree.
 388          */
 389         if (nblocks > fs_info->csums_per_leaf)
 390                 path->reada = READA_FORWARD;
 391
 392         /*
 393          * the free space stuff is only read when it hasn't been
 394          * updated in the current transaction.  So, we can safely
 395          * read from the commit root and sidestep a nasty deadlock
 396          * between reading the free space cache and updating the csum tree.
 397          */
 398         if (btrfs_is_free_space_inode(inode)) {
 399                 path->search_commit_root = 1;
 400                 path->skip_locking = 1;
 401         }
 402
 403         while (bio_offset < orig_len) {
 404                 int count;
 405                 u64 cur_disk_bytenr = orig_disk_bytenr + bio_offset;
 406                 u8 *csum_dst = bbio->csum +
 407                         (bio_offset >> fs_info->sectorsize_bits) * csum_size;
 408
 409                 count = search_csum_tree(fs_info, path, cur_disk_bytenr,
 410                                          orig_len - bio_offset, csum_dst);
 411                 if (count < 0) {
 412                         ret = errno_to_blk_status(count);
 413                         if (bbio->csum != bbio->csum_inline)
 414                                 kfree(bbio->csum);
 415                         bbio->csum = NULL;
 416                         break;
 417                 }
 418
 419                 /*
 420                  * We didn't find a csum for this range.  We need to make sure
 421                  * we complain loudly about this, because we are not NODATASUM.
 422                  *
 423                  * However for the DATA_RELOC inode we could potentially be
 424                  * relocating data extents for a NODATASUM inode, so the inode
 425                  * itself won't be marked with NODATASUM, but the extent we're
 426                  * copying is in fact NODATASUM.  If we don't find a csum we
 427                  * assume this is the case.
 428                  */
 429                 if (count == 0) {
 430                         memset(csum_dst, 0, csum_size);
 431                         count = 1;
 432
 433                         if (inode->root->root_key.objectid ==
 434                             BTRFS_DATA_RELOC_TREE_OBJECTID) {
 435                                 u64 file_offset = bbio->file_offset + bio_offset;
 436
 437                                 set_extent_bit(&inode->io_tree, file_offset,
 438                                                file_offset + sectorsize - 1,
 439                                                EXTENT_NODATASUM, NULL);
 440                         } else {
 441                                 btrfs_warn_rl(fs_info,
 442                         "csum hole found for disk bytenr range [%llu, %llu)",
 443                                 cur_disk_bytenr, cur_disk_bytenr + sectorsize);
 444                         }
 445                 }
 446                 bio_offset += count * sectorsize;
 447         }
 448
 449         btrfs_free_path(path);
 450         return ret;
 451 }
 452
 453 int btrfs_lookup_csums_list(struct btrfs_root *root, u64 start, u64 end,
 454                             struct list_head *list, int search_commit,
 455                             bool nowait)
 456 {
 457         struct btrfs_fs_info *fs_info = root->fs_info;
 458         struct btrfs_key key;
 459         struct btrfs_path *path;
 460         struct extent_buffer *leaf;
 461         struct btrfs_ordered_sum *sums;
 462         struct btrfs_csum_item *item;
 463         LIST_HEAD(tmplist);
 464         int ret;
 465
 466         ASSERT(IS_ALIGNED(start, fs_info->sectorsize) &&
 467                IS_ALIGNED(end + 1, fs_info->sectorsize));
 468
 469         path = btrfs_alloc_path();
 470         if (!path)
 471                 return -ENOMEM;
 472
 473         path->nowait = nowait;
 474         if (search_commit) {
 475                 path->skip_locking = 1;
 476                 path->reada = READA_FORWARD;
 477                 path->search_commit_root = 1;
 478         }
 479
 480         key.objectid = BTRFS_EXTENT_CSUM_OBJECTID;
 481         key.offset = start;
 482         key.type = BTRFS_EXTENT_CSUM_KEY;
 483
 484         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
 485         if (ret < 0)
 486                 goto fail;
 487         if (ret > 0 && path->slots[0] > 0) {
 488                 leaf = path->nodes[0];
 489                 btrfs_item_key_to_cpu(leaf, &key, path->slots[0] - 1);
 490
 491                 /*
 492                  * There are two cases we can hit here for the previous csum
 493                  * item:
 494                  *
 495                  *              |<- search range ->|
 496                  *      |<- csum item ->|
 497                  *
 498                  * Or
 499                  *                              |<- search range ->|
 500                  *      |<- csum item ->|
 501                  *
 502                  * Check if the previous csum item covers the leading part of
 503                  * the search range.  If so we have to start from previous csum
 504                  * item.
 505                  */
 506                 if (key.objectid == BTRFS_EXTENT_CSUM_OBJECTID &&
 507                     key.type == BTRFS_EXTENT_CSUM_KEY) {
 508                         if (bytes_to_csum_size(fs_info, start - key.offset) <
 509                             btrfs_item_size(leaf, path->slots[0] - 1))
 510                                 path->slots[0]--;
 511                 }
 512         }
 513
 514         while (start <= end) {
 515                 u64 csum_end;
 516
 517                 leaf = path->nodes[0];
 518                 if (path->slots[0] >= btrfs_header_nritems(leaf)) {
 519                         ret = btrfs_next_leaf(root, path);
 520                         if (ret < 0)
 521                                 goto fail;
 522                         if (ret > 0)
 523                                 break;
 524                         leaf = path->nodes[0];
 525                 }
 526
 527                 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
 528                 if (key.objectid != BTRFS_EXTENT_CSUM_OBJECTID ||
 529                     key.type != BTRFS_EXTENT_CSUM_KEY ||
 530                     key.offset > end)
 531                         break;
 532
 533                 if (key.offset > start)
 534                         start = key.offset;
 535
 536                 csum_end = key.offset + csum_size_to_bytes(fs_info,
 537                                         btrfs_item_size(leaf, path->slots[0]));
 538                 if (csum_end <= start) {
 539                         path->slots[0]++;
 540                         continue;
 541                 }
 542
 543                 csum_end = min(csum_end, end + 1);
 544                 item = btrfs_item_ptr(path->nodes[0], path->slots[0],
 545                                       struct btrfs_csum_item);
 546                 while (start < csum_end) {
 547                         unsigned long offset;
 548                         size_t size;
 549
 550                         size = min_t(size_t, csum_end - start,
 551                                      max_ordered_sum_bytes(fs_info));
 552                         sums = kzalloc(btrfs_ordered_sum_size(fs_info, size),
 553                                        GFP_NOFS);
 554                         if (!sums) {
 555                                 ret = -ENOMEM;
 556                                 goto fail;
 557                         }
 558
 559                         sums->logical = start;
 560                         sums->len = size;
 561
 562                         offset = bytes_to_csum_size(fs_info, start - key.offset);
 563
 564                         read_extent_buffer(path->nodes[0],
 565                                            sums->sums,
 566                                            ((unsigned long)item) + offset,
 567                                            bytes_to_csum_size(fs_info, size));
 568
 569                         start += size;
 570                         list_add_tail(&sums->list, &tmplist);
 571                 }
 572                 path->slots[0]++;
 573         }
 574         ret = 0;
 575 fail:
 576         while (ret < 0 && !list_empty(&tmplist)) {
 577                 sums = list_entry(tmplist.next, struct btrfs_ordered_sum, list);
 578                 list_del(&sums->list);
 579                 kfree(sums);
 580         }
 581         list_splice_tail(&tmplist, list);
 582
 583         btrfs_free_path(path);
 584         return ret;
 585 }
 586
 587 /*
 588  * Do the same work as btrfs_lookup_csums_list(), the difference is in how
 589  * we return the result.
 590  *
 591  * This version will set the corresponding bits in @csum_bitmap to represent
 592  * that there is a csum found.
 593  * Each bit represents a sector. Thus caller should ensure @csum_buf passed
 594  * in is large enough to contain all csums.
 595  */
 596 int btrfs_lookup_csums_bitmap(struct btrfs_root *root, struct btrfs_path *path,
 597                               u64 start, u64 end, u8 *csum_buf,
 598                               unsigned long *csum_bitmap)
 599 {
 600         struct btrfs_fs_info *fs_info = root->fs_info;
 601         struct btrfs_key key;
 602         struct extent_buffer *leaf;
 603         struct btrfs_csum_item *item;
 604         const u64 orig_start = start;
 605         bool free_path = false;
 606         int ret;
 607
 608         ASSERT(IS_ALIGNED(start, fs_info->sectorsize) &&
 609                IS_ALIGNED(end + 1, fs_info->sectorsize));
 610
 611         if (!path) {
 612                 path = btrfs_alloc_path();
 613                 if (!path)
 614                         return -ENOMEM;
 615                 free_path = true;
 616         }
 617
 618         /* Check if we can reuse the previous path. */
 619         if (path->nodes[0]) {
 620                 btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
 621
 622                 if (key.objectid == BTRFS_EXTENT_CSUM_OBJECTID &&
 623                     key.type == BTRFS_EXTENT_CSUM_KEY &&
 624                     key.offset <= start)
 625                         goto search_forward;
 626                 btrfs_release_path(path);
 627         }
 628
 629         key.objectid = BTRFS_EXTENT_CSUM_OBJECTID;
 630         key.type = BTRFS_EXTENT_CSUM_KEY;
 631         key.offset = start;
 632
 633         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
 634         if (ret < 0)
 635                 goto fail;
 636         if (ret > 0 && path->slots[0] > 0) {
 637                 leaf = path->nodes[0];
 638                 btrfs_item_key_to_cpu(leaf, &key, path->slots[0] - 1);
 639
 640                 /*
 641                  * There are two cases we can hit here for the previous csum
 642                  * item:
 643                  *
 644                  *              |<- search range ->|
 645                  *      |<- csum item ->|
 646                  *
 647                  * Or
 648                  *                              |<- search range ->|
 649                  *      |<- csum item ->|
 650                  *
 651                  * Check if the previous csum item covers the leading part of
 652                  * the search range.  If so we have to start from previous csum
 653                  * item.
 654                  */
 655                 if (key.objectid == BTRFS_EXTENT_CSUM_OBJECTID &&
 656                     key.type == BTRFS_EXTENT_CSUM_KEY) {
 657                         if (bytes_to_csum_size(fs_info, start - key.offset) <
 658                             btrfs_item_size(leaf, path->slots[0] - 1))
 659                                 path->slots[0]--;
 660                 }
 661         }
 662
 663 search_forward:
 664         while (start <= end) {
 665                 u64 csum_end;
 666
 667                 leaf = path->nodes[0];
 668                 if (path->slots[0] >= btrfs_header_nritems(leaf)) {
 669                         ret = btrfs_next_leaf(root, path);
 670                         if (ret < 0)
 671                                 goto fail;
 672                         if (ret > 0)
 673                                 break;
 674                         leaf = path->nodes[0];
 675                 }
 676
 677                 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
 678                 if (key.objectid != BTRFS_EXTENT_CSUM_OBJECTID ||
 679                     key.type != BTRFS_EXTENT_CSUM_KEY ||
 680                     key.offset > end)
 681                         break;
 682
 683                 if (key.offset > start)
 684                         start = key.offset;
 685
 686                 csum_end = key.offset + csum_size_to_bytes(fs_info,
 687                                         btrfs_item_size(leaf, path->slots[0]));
 688                 if (csum_end <= start) {
 689                         path->slots[0]++;
 690                         continue;
 691                 }
 692
 693                 csum_end = min(csum_end, end + 1);
 694                 item = btrfs_item_ptr(path->nodes[0], path->slots[0],
 695                                       struct btrfs_csum_item);
 696                 while (start < csum_end) {
 697                         unsigned long offset;
 698                         size_t size;
 699                         u8 *csum_dest = csum_buf + bytes_to_csum_size(fs_info,
 700                                                 start - orig_start);
 701
 702                         size = min_t(size_t, csum_end - start, end + 1 - start);
 703
 704                         offset = bytes_to_csum_size(fs_info, start - key.offset);
 705
 706                         read_extent_buffer(path->nodes[0], csum_dest,
 707                                            ((unsigned long)item) + offset,
 708                                            bytes_to_csum_size(fs_info, size));
 709
 710                         bitmap_set(csum_bitmap,
 711                                 (start - orig_start) >> fs_info->sectorsize_bits,
 712                                 size >> fs_info->sectorsize_bits);
 713
 714                         start += size;
 715                 }
 716                 path->slots[0]++;
 717         }
 718         ret = 0;
 719 fail:
 720         if (free_path)
 721                 btrfs_free_path(path);
 722         return ret;
 723 }
 724
 725 /*
 726  * Calculate checksums of the data contained inside a bio.
 727  */
 728 blk_status_t btrfs_csum_one_bio(struct btrfs_bio *bbio)
 729 {
 730         struct btrfs_ordered_extent *ordered = bbio->ordered;
 731         struct btrfs_inode *inode = bbio->inode;
 732         struct btrfs_fs_info *fs_info = inode->root->fs_info;
 733         SHASH_DESC_ON_STACK(shash, fs_info->csum_shash);
 734         struct bio *bio = &bbio->bio;
 735         struct btrfs_ordered_sum *sums;
 736         char *data;
 737         struct bvec_iter iter;
 738         struct bio_vec bvec;
 739         int index;
 740         unsigned int blockcount;
 741         int i;
 742         unsigned nofs_flag;
 743
 744         nofs_flag = memalloc_nofs_save();
 745         sums = kvzalloc(btrfs_ordered_sum_size(fs_info, bio->bi_iter.bi_size),
 746                        GFP_KERNEL);
 747         memalloc_nofs_restore(nofs_flag);
 748
 749         if (!sums)
 750                 return BLK_STS_RESOURCE;
 751
 752         sums->len = bio->bi_iter.bi_size;
 753         INIT_LIST_HEAD(&sums->list);
 754
 755         sums->logical = bio->bi_iter.bi_sector << SECTOR_SHIFT;
 756         index = 0;
 757
 758         shash->tfm = fs_info->csum_shash;
 759
 760         bio_for_each_segment(bvec, bio, iter) {
 761                 blockcount = BTRFS_BYTES_TO_BLKS(fs_info,
 762                                                  bvec.bv_len + fs_info->sectorsize
 763                                                  - 1);
 764
 765                 for (i = 0; i < blockcount; i++) {
 766                         data = bvec_kmap_local(&bvec);
 767                         crypto_shash_digest(shash,
 768                                             data + (i * fs_info->sectorsize),
 769                                             fs_info->sectorsize,
 770                                             sums->sums + index);
 771                         kunmap_local(data);
 772                         index += fs_info->csum_size;
 773                 }
 774
 775         }
 776
 777         bbio->sums = sums;
 778         btrfs_add_ordered_sum(ordered, sums);
 779         return 0;
 780 }
 781
 782 /*
 783  * Nodatasum I/O on zoned file systems still requires an btrfs_ordered_sum to
 784  * record the updated logical address on Zone Append completion.
 785  * Allocate just the structure with an empty sums array here for that case.
 786  */
 787 blk_status_t btrfs_alloc_dummy_sum(struct btrfs_bio *bbio)
 788 {
 789         bbio->sums = kmalloc(sizeof(*bbio->sums), GFP_NOFS);
 790         if (!bbio->sums)
 791                 return BLK_STS_RESOURCE;
 792         bbio->sums->len = bbio->bio.bi_iter.bi_size;
 793         bbio->sums->logical = bbio->bio.bi_iter.bi_sector << SECTOR_SHIFT;
 794         btrfs_add_ordered_sum(bbio->ordered, bbio->sums);
 795         return 0;
 796 }
 797
 798 /*
 799  * Remove one checksum overlapping a range.
 800  *
 801  * This expects the key to describe the csum pointed to by the path, and it
 802  * expects the csum to overlap the range [bytenr, len]
 803  *
 804  * The csum should not be entirely contained in the range and the range should
 805  * not be entirely contained in the csum.
 806  *
 807  * This calls btrfs_truncate_item with the correct args based on the overlap,
 808  * and fixes up the key as required.
 809  */
 810 static noinline void truncate_one_csum(struct btrfs_trans_handle *trans,
 811                                        struct btrfs_path *path,
 812                                        struct btrfs_key *key,
 813                                        u64 bytenr, u64 len)
 814 {
 815         struct btrfs_fs_info *fs_info = trans->fs_info;
 816         struct extent_buffer *leaf;
 817         const u32 csum_size = fs_info->csum_size;
 818         u64 csum_end;
 819         u64 end_byte = bytenr + len;
 820         u32 blocksize_bits = fs_info->sectorsize_bits;
 821
 822         leaf = path->nodes[0];
 823         csum_end = btrfs_item_size(leaf, path->slots[0]) / csum_size;
 824         csum_end <<= blocksize_bits;
 825         csum_end += key->offset;
 826
 827         if (key->offset < bytenr && csum_end <= end_byte) {
 828                 /*
 829                  *         [ bytenr - len ]
 830                  *         [   ]
 831                  *   [csum     ]
 832                  *   A simple truncate off the end of the item
 833                  */
 834                 u32 new_size = (bytenr - key->offset) >> blocksize_bits;
 835                 new_size *= csum_size;
 836                 btrfs_truncate_item(trans, path, new_size, 1);
 837         } else if (key->offset >= bytenr && csum_end > end_byte &&
 838                    end_byte > key->offset) {
 839                 /*
 840                  *         [ bytenr - len ]
 841                  *                 [ ]
 842                  *                 [csum     ]
 843                  * we need to truncate from the beginning of the csum
 844                  */
 845                 u32 new_size = (csum_end - end_byte) >> blocksize_bits;
 846                 new_size *= csum_size;
 847
 848                 btrfs_truncate_item(trans, path, new_size, 0);
 849
 850                 key->offset = end_byte;
 851                 btrfs_set_item_key_safe(trans, path, key);
 852         } else {
 853                 BUG();
 854         }
 855 }
 856
 857 /*
 858  * Delete the csum items from the csum tree for a given range of bytes.
 859  */
 860 int btrfs_del_csums(struct btrfs_trans_handle *trans,
 861                     struct btrfs_root *root, u64 bytenr, u64 len)
 862 {
 863         struct btrfs_fs_info *fs_info = trans->fs_info;
 864         struct btrfs_path *path;
 865         struct btrfs_key key;
 866         u64 end_byte = bytenr + len;
 867         u64 csum_end;
 868         struct extent_buffer *leaf;
 869         int ret = 0;
 870         const u32 csum_size = fs_info->csum_size;
 871         u32 blocksize_bits = fs_info->sectorsize_bits;
 872
 873         ASSERT(root->root_key.objectid == BTRFS_CSUM_TREE_OBJECTID ||
 874                root->root_key.objectid == BTRFS_TREE_LOG_OBJECTID);
 875
 876         path = btrfs_alloc_path();
 877         if (!path)
 878                 return -ENOMEM;
 879
 880         while (1) {
 881                 key.objectid = BTRFS_EXTENT_CSUM_OBJECTID;
 882                 key.offset = end_byte - 1;
 883                 key.type = BTRFS_EXTENT_CSUM_KEY;
 884
 885                 ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
 886                 if (ret > 0) {
 887                         ret = 0;
 888                         if (path->slots[0] == 0)
 889                                 break;
 890                         path->slots[0]--;
 891                 } else if (ret < 0) {
 892                         break;
 893                 }
 894
 895                 leaf = path->nodes[0];
 896                 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
 897
 898                 if (key.objectid != BTRFS_EXTENT_CSUM_OBJECTID ||
 899                     key.type != BTRFS_EXTENT_CSUM_KEY) {
 900                         break;
 901                 }
 902
 903                 if (key.offset >= end_byte)
 904                         break;
 905
 906                 csum_end = btrfs_item_size(leaf, path->slots[0]) / csum_size;
 907                 csum_end <<= blocksize_bits;
 908                 csum_end += key.offset;
 909
 910                 /* this csum ends before we start, we're done */
 911                 if (csum_end <= bytenr)
 912                         break;
 913
 914                 /* delete the entire item, it is inside our range */
 915                 if (key.offset >= bytenr && csum_end <= end_byte) {
 916                         int del_nr = 1;
 917
 918                         /*
 919                          * Check how many csum items preceding this one in this
 920                          * leaf correspond to our range and then delete them all
 921                          * at once.
 922                          */
 923                         if (key.offset > bytenr && path->slots[0] > 0) {
 924                                 int slot = path->slots[0] - 1;
 925
 926                                 while (slot >= 0) {
 927                                         struct btrfs_key pk;
 928
 929                                         btrfs_item_key_to_cpu(leaf, &pk, slot);
 930                                         if (pk.offset < bytenr ||
 931                                             pk.type != BTRFS_EXTENT_CSUM_KEY ||
 932                                             pk.objectid !=
 933                                             BTRFS_EXTENT_CSUM_OBJECTID)
 934                                                 break;
 935                                         path->slots[0] = slot;
 936                                         del_nr++;
 937                                         key.offset = pk.offset;
 938                                         slot--;
 939                                 }
 940                         }
 941                         ret = btrfs_del_items(trans, root, path,
 942                                               path->slots[0], del_nr);
 943                         if (ret)
 944                                 break;
 945                         if (key.offset == bytenr)
 946                                 break;
 947                 } else if (key.offset < bytenr && csum_end > end_byte) {
 948                         unsigned long offset;
 949                         unsigned long shift_len;
 950                         unsigned long item_offset;
 951                         /*
 952                          *        [ bytenr - len ]
 953                          *     [csum                ]
 954                          *
 955                          * Our bytes are in the middle of the csum,
 956                          * we need to split this item and insert a new one.
 957                          *
 958                          * But we can't drop the path because the
 959                          * csum could change, get removed, extended etc.
 960                          *
 961                          * The trick here is the max size of a csum item leaves
 962                          * enough room in the tree block for a single
 963                          * item header.  So, we split the item in place,
 964                          * adding a new header pointing to the existing
 965                          * bytes.  Then we loop around again and we have
 966                          * a nicely formed csum item that we can neatly
 967                          * truncate.
 968                          */
 969                         offset = (bytenr - key.offset) >> blocksize_bits;
 970                         offset *= csum_size;
 971
 972                         shift_len = (len >> blocksize_bits) * csum_size;
 973
 974                         item_offset = btrfs_item_ptr_offset(leaf,
 975                                                             path->slots[0]);
 976
 977                         memzero_extent_buffer(leaf, item_offset + offset,
 978                                              shift_len);
 979                         key.offset = bytenr;
 980
 981                         /*
 982                          * btrfs_split_item returns -EAGAIN when the
 983                          * item changed size or key
 984                          */
 985                         ret = btrfs_split_item(trans, root, path, &key, offset);
 986                         if (ret && ret != -EAGAIN) {
 987                                 btrfs_abort_transaction(trans, ret);
 988                                 break;
 989                         }
 990                         ret = 0;
 991
 992                         key.offset = end_byte - 1;
 993                 } else {
 994                         truncate_one_csum(trans, path, &key, bytenr, len);
 995                         if (key.offset < bytenr)
 996                                 break;
 997                 }
 998                 btrfs_release_path(path);
 999         }
1000         btrfs_free_path(path);
1001         return ret;
1002 }
1003
1004 static int find_next_csum_offset(struct btrfs_root *root,
1005                                  struct btrfs_path *path,
1006                                  u64 *next_offset)
1007 {
1008         const u32 nritems = btrfs_header_nritems(path->nodes[0]);
1009         struct btrfs_key found_key;
1010         int slot = path->slots[0] + 1;
1011         int ret;
1012
1013         if (nritems == 0 || slot >= nritems) {
1014                 ret = btrfs_next_leaf(root, path);
1015                 if (ret < 0) {
1016                         return ret;
1017                 } else if (ret > 0) {
1018                         *next_offset = (u64)-1;
1019                         return 0;
1020                 }
1021                 slot = path->slots[0];
1022         }
1023
1024         btrfs_item_key_to_cpu(path->nodes[0], &found_key, slot);
1025
1026         if (found_key.objectid != BTRFS_EXTENT_CSUM_OBJECTID ||
1027             found_key.type != BTRFS_EXTENT_CSUM_KEY)
1028                 *next_offset = (u64)-1;
1029         else
1030                 *next_offset = found_key.offset;
1031
1032         return 0;
1033 }
1034
1035 int btrfs_csum_file_blocks(struct btrfs_trans_handle *trans,
1036                            struct btrfs_root *root,
1037                            struct btrfs_ordered_sum *sums)
1038 {
1039         struct btrfs_fs_info *fs_info = root->fs_info;
1040         struct btrfs_key file_key;
1041         struct btrfs_key found_key;
1042         struct btrfs_path *path;
1043         struct btrfs_csum_item *item;
1044         struct btrfs_csum_item *item_end;
1045         struct extent_buffer *leaf = NULL;
1046         u64 next_offset;
1047         u64 total_bytes = 0;
1048         u64 csum_offset;
1049         u64 bytenr;
1050         u32 ins_size;
1051         int index = 0;
1052         int found_next;
1053         int ret;
1054         const u32 csum_size = fs_info->csum_size;
1055
1056         path = btrfs_alloc_path();
1057         if (!path)
1058                 return -ENOMEM;
1059 again:
1060         next_offset = (u64)-1;
1061         found_next = 0;
1062         bytenr = sums->logical + total_bytes;
1063         file_key.objectid = BTRFS_EXTENT_CSUM_OBJECTID;
1064         file_key.offset = bytenr;
1065         file_key.type = BTRFS_EXTENT_CSUM_KEY;
1066
1067         item = btrfs_lookup_csum(trans, root, path, bytenr, 1);
1068         if (!IS_ERR(item)) {
1069                 ret = 0;
1070                 leaf = path->nodes[0];
1071                 item_end = btrfs_item_ptr(leaf, path->slots[0],
1072                                           struct btrfs_csum_item);
1073                 item_end = (struct btrfs_csum_item *)((char *)item_end +
1074                            btrfs_item_size(leaf, path->slots[0]));
1075                 goto found;
1076         }
1077         ret = PTR_ERR(item);
1078         if (ret != -EFBIG && ret != -ENOENT)
1079                 goto out;
1080
1081         if (ret == -EFBIG) {
1082                 u32 item_size;
1083                 /* we found one, but it isn't big enough yet */
1084                 leaf = path->nodes[0];
1085                 item_size = btrfs_item_size(leaf, path->slots[0]);
1086                 if ((item_size / csum_size) >=
1087                     MAX_CSUM_ITEMS(fs_info, csum_size)) {
1088                         /* already at max size, make a new one */
1089                         goto insert;
1090                 }
1091         } else {
1092                 /* We didn't find a csum item, insert one. */
1093                 ret = find_next_csum_offset(root, path, &next_offset);
1094                 if (ret < 0)
1095                         goto out;
1096                 found_next = 1;
1097                 goto insert;
1098         }
1099
1100         /*
1101          * At this point, we know the tree has a checksum item that ends at an
1102          * offset matching the start of the checksum range we want to insert.
1103          * We try to extend that item as much as possible and then add as many
1104          * checksums to it as they fit.
1105          *
1106          * First check if the leaf has enough free space for at least one
1107          * checksum. If it has go directly to the item extension code, otherwise
1108          * release the path and do a search for insertion before the extension.
1109          */
1110         if (btrfs_leaf_free_space(leaf) >= csum_size) {
1111                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
1112                 csum_offset = (bytenr - found_key.offset) >>
1113                         fs_info->sectorsize_bits;
1114                 goto extend_csum;
1115         }
1116
1117         btrfs_release_path(path);
1118         path->search_for_extension = 1;
1119         ret = btrfs_search_slot(trans, root, &file_key, path,
1120                                 csum_size, 1);
1121         path->search_for_extension = 0;
1122         if (ret < 0)
1123                 goto out;
1124
1125         if (ret > 0) {
1126                 if (path->slots[0] == 0)
1127                         goto insert;
1128                 path->slots[0]--;
1129         }
1130
1131         leaf = path->nodes[0];
1132         btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
1133         csum_offset = (bytenr - found_key.offset) >> fs_info->sectorsize_bits;
1134
1135         if (found_key.type != BTRFS_EXTENT_CSUM_KEY ||
1136             found_key.objectid != BTRFS_EXTENT_CSUM_OBJECTID ||
1137             csum_offset >= MAX_CSUM_ITEMS(fs_info, csum_size)) {
1138                 goto insert;
1139         }
1140
1141 extend_csum:
1142         if (csum_offset == btrfs_item_size(leaf, path->slots[0]) /
1143             csum_size) {
1144                 int extend_nr;
1145                 u64 tmp;
1146                 u32 diff;
1147
1148                 tmp = sums->len - total_bytes;
1149                 tmp >>= fs_info->sectorsize_bits;
1150                 WARN_ON(tmp < 1);
1151                 extend_nr = max_t(int, 1, tmp);
1152
1153                 /*
1154                  * A log tree can already have checksum items with a subset of
1155                  * the checksums we are trying to log. This can happen after
1156                  * doing a sequence of partial writes into prealloc extents and
1157                  * fsyncs in between, with a full fsync logging a larger subrange
1158                  * of an extent for which a previous fast fsync logged a smaller
1159                  * subrange. And this happens in particular due to merging file
1160                  * extent items when we complete an ordered extent for a range
1161                  * covered by a prealloc extent - this is done at
1162                  * btrfs_mark_extent_written().
1163                  *
1164                  * So if we try to extend the previous checksum item, which has
1165                  * a range that ends at the start of the range we want to insert,
1166                  * make sure we don't extend beyond the start offset of the next
1167                  * checksum item. If we are at the last item in the leaf, then
1168                  * forget the optimization of extending and add a new checksum
1169                  * item - it is not worth the complexity of releasing the path,
1170                  * getting the first key for the next leaf, repeat the btree
1171                  * search, etc, because log trees are temporary anyway and it
1172                  * would only save a few bytes of leaf space.
1173                  */
1174                 if (root->root_key.objectid == BTRFS_TREE_LOG_OBJECTID) {
1175                         if (path->slots[0] + 1 >=
1176                             btrfs_header_nritems(path->nodes[0])) {
1177                                 ret = find_next_csum_offset(root, path, &next_offset);
1178                                 if (ret < 0)
1179                                         goto out;
1180                                 found_next = 1;
1181                                 goto insert;
1182                         }
1183
1184                         ret = find_next_csum_offset(root, path, &next_offset);
1185                         if (ret < 0)
1186                                 goto out;
1187
1188                         tmp = (next_offset - bytenr) >> fs_info->sectorsize_bits;
1189                         if (tmp <= INT_MAX)
1190                                 extend_nr = min_t(int, extend_nr, tmp);
1191                 }
1192
1193                 diff = (csum_offset + extend_nr) * csum_size;
1194                 diff = min(diff,
1195                            MAX_CSUM_ITEMS(fs_info, csum_size) * csum_size);
1196
1197                 diff = diff - btrfs_item_size(leaf, path->slots[0]);
1198                 diff = min_t(u32, btrfs_leaf_free_space(leaf), diff);
1199                 diff /= csum_size;
1200                 diff *= csum_size;
1201
1202                 btrfs_extend_item(trans, path, diff);
1203                 ret = 0;
1204                 goto csum;
1205         }
1206
1207 insert:
1208         btrfs_release_path(path);
1209         csum_offset = 0;
1210         if (found_next) {
1211                 u64 tmp;
1212
1213                 tmp = sums->len - total_bytes;
1214                 tmp >>= fs_info->sectorsize_bits;
1215                 tmp = min(tmp, (next_offset - file_key.offset) >>
1216                                          fs_info->sectorsize_bits);
1217
1218                 tmp = max_t(u64, 1, tmp);
1219                 tmp = min_t(u64, tmp, MAX_CSUM_ITEMS(fs_info, csum_size));
1220                 ins_size = csum_size * tmp;
1221         } else {
1222                 ins_size = csum_size;
1223         }
1224         ret = btrfs_insert_empty_item(trans, root, path, &file_key,
1225                                       ins_size);
1226         if (ret < 0)
1227                 goto out;
1228         leaf = path->nodes[0];
1229 csum:
1230         item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_csum_item);
1231         item_end = (struct btrfs_csum_item *)((unsigned char *)item +
1232                                       btrfs_item_size(leaf, path->slots[0]));
1233         item = (struct btrfs_csum_item *)((unsigned char *)item +
1234                                           csum_offset * csum_size);
1235 found:
1236         ins_size = (u32)(sums->len - total_bytes) >> fs_info->sectorsize_bits;
1237         ins_size *= csum_size;
1238         ins_size = min_t(u32, (unsigned long)item_end - (unsigned long)item,
1239                               ins_size);
1240         write_extent_buffer(leaf, sums->sums + index, (unsigned long)item,
1241                             ins_size);
1242
1243         index += ins_size;
1244         ins_size /= csum_size;
1245         total_bytes += ins_size * fs_info->sectorsize;
1246
1247         btrfs_mark_buffer_dirty(trans, path->nodes[0]);
1248         if (total_bytes < sums->len) {
1249                 btrfs_release_path(path);
1250                 cond_resched();
1251                 goto again;
1252         }
1253 out:
1254         btrfs_free_path(path);
1255         return ret;
1256 }
1257
1258 void btrfs_extent_item_to_extent_map(struct btrfs_inode *inode,
1259                                      const struct btrfs_path *path,
1260                                      struct btrfs_file_extent_item *fi,
1261                                      struct extent_map *em)
1262 {
1263         struct btrfs_fs_info *fs_info = inode->root->fs_info;
1264         struct btrfs_root *root = inode->root;
1265         struct extent_buffer *leaf = path->nodes[0];
1266         const int slot = path->slots[0];
1267         struct btrfs_key key;
1268         u64 extent_start, extent_end;
1269         u64 bytenr;
1270         u8 type = btrfs_file_extent_type(leaf, fi);
1271         int compress_type = btrfs_file_extent_compression(leaf, fi);
1272
1273         btrfs_item_key_to_cpu(leaf, &key, slot);
1274         extent_start = key.offset;
1275         extent_end = btrfs_file_extent_end(path);
1276         em->ram_bytes = btrfs_file_extent_ram_bytes(leaf, fi);
1277         em->generation = btrfs_file_extent_generation(leaf, fi);
1278         if (type == BTRFS_FILE_EXTENT_REG ||
1279             type == BTRFS_FILE_EXTENT_PREALLOC) {
1280                 em->start = extent_start;
1281                 em->len = extent_end - extent_start;
1282                 em->orig_start = extent_start -
1283                         btrfs_file_extent_offset(leaf, fi);
1284                 em->orig_block_len = btrfs_file_extent_disk_num_bytes(leaf, fi);
1285                 bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
1286                 if (bytenr == 0) {
1287                         em->block_start = EXTENT_MAP_HOLE;
1288                         return;
1289                 }
1290                 if (compress_type != BTRFS_COMPRESS_NONE) {
1291                         extent_map_set_compression(em, compress_type);
1292                         em->block_start = bytenr;
1293                         em->block_len = em->orig_block_len;
1294                 } else {
1295                         bytenr += btrfs_file_extent_offset(leaf, fi);
1296                         em->block_start = bytenr;
1297                         em->block_len = em->len;
1298                         if (type == BTRFS_FILE_EXTENT_PREALLOC)
1299                                 em->flags |= EXTENT_FLAG_PREALLOC;
1300                 }
1301         } else if (type == BTRFS_FILE_EXTENT_INLINE) {
1302                 em->block_start = EXTENT_MAP_INLINE;
1303                 em->start = extent_start;
1304                 em->len = extent_end - extent_start;
1305                 /*
1306                  * Initialize orig_start and block_len with the same values
1307                  * as in inode.c:btrfs_get_extent().
1308                  */
1309                 em->orig_start = EXTENT_MAP_HOLE;
1310                 em->block_len = (u64)-1;
1311                 extent_map_set_compression(em, compress_type);
1312         } else {
1313                 btrfs_err(fs_info,
1314                           "unknown file extent item type %d, inode %llu, offset %llu, "
1315                           "root %llu", type, btrfs_ino(inode), extent_start,
1316                           root->root_key.objectid);
1317         }
1318 }
1319
1320 /*
1321  * Returns the end offset (non inclusive) of the file extent item the given path
1322  * points to. If it points to an inline extent, the returned offset is rounded
1323  * up to the sector size.
1324  */
1325 u64 btrfs_file_extent_end(const struct btrfs_path *path)
1326 {
1327         const struct extent_buffer *leaf = path->nodes[0];
1328         const int slot = path->slots[0];
1329         struct btrfs_file_extent_item *fi;
1330         struct btrfs_key key;
1331         u64 end;
1332
1333         btrfs_item_key_to_cpu(leaf, &key, slot);
1334         ASSERT(key.type == BTRFS_EXTENT_DATA_KEY);
1335         fi = btrfs_item_ptr(leaf, slot, struct btrfs_file_extent_item);
1336
1337         if (btrfs_file_extent_type(leaf, fi) == BTRFS_FILE_EXTENT_INLINE) {
1338                 end = btrfs_file_extent_ram_bytes(leaf, fi);
1339                 end = ALIGN(key.offset + end, leaf->fs_info->sectorsize);
1340         } else {
1341                 end = key.offset + btrfs_file_extent_num_bytes(leaf, fi);
1342         }
1343
1344         return end;
1345 }