2 * Copyright (C) 2007 Oracle. All rights reserved.
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU General Public
6 * License v2 as published by the Free Software Foundation.
8 * This program is distributed in the hope that it will be useful,
9 * but WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
11 * General Public License for more details.
13 * You should have received a copy of the GNU General Public
14 * License along with this program; if not, write to the
15 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
16 * Boston, MA 021110-1307, USA.
19 #include <linux/bio.h>
20 #include <linux/slab.h>
21 #include <linux/pagemap.h>
22 #include <linux/highmem.h>
25 #include "transaction.h"
26 #include "print-tree.h"
28 #define __MAX_CSUM_ITEMS(r, size) ((unsigned long)(((BTRFS_LEAF_DATA_SIZE(r) - \
29 sizeof(struct btrfs_item) * 2) / \
32 #define MAX_CSUM_ITEMS(r, size) (min_t(u32, __MAX_CSUM_ITEMS(r, size), \
35 #define MAX_ORDERED_SUM_BYTES(r) ((PAGE_SIZE - \
36 sizeof(struct btrfs_ordered_sum)) / \
37 sizeof(struct btrfs_sector_sum) * \
38 (r)->sectorsize - (r)->sectorsize)
40 int btrfs_insert_file_extent(struct btrfs_trans_handle *trans,
41 struct btrfs_root *root,
42 u64 objectid, u64 pos,
43 u64 disk_offset, u64 disk_num_bytes,
44 u64 num_bytes, u64 offset, u64 ram_bytes,
45 u8 compression, u8 encryption, u16 other_encoding)
48 struct btrfs_file_extent_item *item;
49 struct btrfs_key file_key;
50 struct btrfs_path *path;
51 struct extent_buffer *leaf;
53 path = btrfs_alloc_path();
56 file_key.objectid = objectid;
57 file_key.offset = pos;
58 btrfs_set_key_type(&file_key, BTRFS_EXTENT_DATA_KEY);
60 path->leave_spinning = 1;
61 ret = btrfs_insert_empty_item(trans, root, path, &file_key,
65 BUG_ON(ret); /* Can't happen */
66 leaf = path->nodes[0];
67 item = btrfs_item_ptr(leaf, path->slots[0],
68 struct btrfs_file_extent_item);
69 btrfs_set_file_extent_disk_bytenr(leaf, item, disk_offset);
70 btrfs_set_file_extent_disk_num_bytes(leaf, item, disk_num_bytes);
71 btrfs_set_file_extent_offset(leaf, item, offset);
72 btrfs_set_file_extent_num_bytes(leaf, item, num_bytes);
73 btrfs_set_file_extent_ram_bytes(leaf, item, ram_bytes);
74 btrfs_set_file_extent_generation(leaf, item, trans->transid);
75 btrfs_set_file_extent_type(leaf, item, BTRFS_FILE_EXTENT_REG);
76 btrfs_set_file_extent_compression(leaf, item, compression);
77 btrfs_set_file_extent_encryption(leaf, item, encryption);
78 btrfs_set_file_extent_other_encoding(leaf, item, other_encoding);
80 btrfs_mark_buffer_dirty(leaf);
82 btrfs_free_path(path);
86 struct btrfs_csum_item *btrfs_lookup_csum(struct btrfs_trans_handle *trans,
87 struct btrfs_root *root,
88 struct btrfs_path *path,
92 struct btrfs_key file_key;
93 struct btrfs_key found_key;
94 struct btrfs_csum_item *item;
95 struct extent_buffer *leaf;
97 u16 csum_size = btrfs_super_csum_size(root->fs_info->super_copy);
100 file_key.objectid = BTRFS_EXTENT_CSUM_OBJECTID;
101 file_key.offset = bytenr;
102 btrfs_set_key_type(&file_key, BTRFS_EXTENT_CSUM_KEY);
103 ret = btrfs_search_slot(trans, root, &file_key, path, 0, cow);
106 leaf = path->nodes[0];
109 if (path->slots[0] == 0)
112 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
113 if (btrfs_key_type(&found_key) != BTRFS_EXTENT_CSUM_KEY)
116 csum_offset = (bytenr - found_key.offset) >>
117 root->fs_info->sb->s_blocksize_bits;
118 csums_in_item = btrfs_item_size_nr(leaf, path->slots[0]);
119 csums_in_item /= csum_size;
121 if (csum_offset == csums_in_item) {
124 } else if (csum_offset > csums_in_item) {
128 item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_csum_item);
129 item = (struct btrfs_csum_item *)((unsigned char *)item +
130 csum_offset * csum_size);
138 int btrfs_lookup_file_extent(struct btrfs_trans_handle *trans,
139 struct btrfs_root *root,
140 struct btrfs_path *path, u64 objectid,
144 struct btrfs_key file_key;
145 int ins_len = mod < 0 ? -1 : 0;
148 file_key.objectid = objectid;
149 file_key.offset = offset;
150 btrfs_set_key_type(&file_key, BTRFS_EXTENT_DATA_KEY);
151 ret = btrfs_search_slot(trans, root, &file_key, path, ins_len, cow);
155 u64 btrfs_file_extent_length(struct btrfs_path *path)
158 struct btrfs_file_extent_item *fi;
161 fi = btrfs_item_ptr(path->nodes[0], path->slots[0],
162 struct btrfs_file_extent_item);
163 extent_type = btrfs_file_extent_type(path->nodes[0], fi);
165 if (extent_type == BTRFS_FILE_EXTENT_REG ||
166 extent_type == BTRFS_FILE_EXTENT_PREALLOC)
167 len = btrfs_file_extent_num_bytes(path->nodes[0], fi);
168 else if (extent_type == BTRFS_FILE_EXTENT_INLINE)
169 len = btrfs_file_extent_inline_len(path->nodes[0], fi);
176 static int __btrfs_lookup_bio_sums(struct btrfs_root *root,
177 struct inode *inode, struct bio *bio,
178 u64 logical_offset, u32 *dst, int dio)
181 struct bio_vec *bvec = bio->bi_io_vec;
184 u64 item_start_offset = 0;
185 u64 item_last_offset = 0;
188 u16 csum_size = btrfs_super_csum_size(root->fs_info->super_copy);
190 struct btrfs_path *path;
191 struct btrfs_csum_item *item = NULL;
192 struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
194 path = btrfs_alloc_path();
197 if (bio->bi_size > PAGE_CACHE_SIZE * 8)
200 WARN_ON(bio->bi_vcnt <= 0);
203 * the free space stuff is only read when it hasn't been
204 * updated in the current transaction. So, we can safely
205 * read from the commit root and sidestep a nasty deadlock
206 * between reading the free space cache and updating the csum tree.
208 if (btrfs_is_free_space_inode(inode)) {
209 path->search_commit_root = 1;
210 path->skip_locking = 1;
213 disk_bytenr = (u64)bio->bi_sector << 9;
215 offset = logical_offset;
216 while (bio_index < bio->bi_vcnt) {
218 offset = page_offset(bvec->bv_page) + bvec->bv_offset;
219 ret = btrfs_find_ordered_sum(inode, offset, disk_bytenr, &sum);
223 if (!item || disk_bytenr < item_start_offset ||
224 disk_bytenr >= item_last_offset) {
225 struct btrfs_key found_key;
229 btrfs_release_path(path);
230 item = btrfs_lookup_csum(NULL, root->fs_info->csum_root,
231 path, disk_bytenr, 0);
234 if (ret == -ENOENT || ret == -EFBIG)
237 if (BTRFS_I(inode)->root->root_key.objectid ==
238 BTRFS_DATA_RELOC_TREE_OBJECTID) {
239 set_extent_bits(io_tree, offset,
240 offset + bvec->bv_len - 1,
241 EXTENT_NODATASUM, GFP_NOFS);
243 printk(KERN_INFO "btrfs no csum found "
244 "for inode %llu start %llu\n",
247 (unsigned long long)offset);
250 btrfs_release_path(path);
253 btrfs_item_key_to_cpu(path->nodes[0], &found_key,
256 item_start_offset = found_key.offset;
257 item_size = btrfs_item_size_nr(path->nodes[0],
259 item_last_offset = item_start_offset +
260 (item_size / csum_size) *
262 item = btrfs_item_ptr(path->nodes[0], path->slots[0],
263 struct btrfs_csum_item);
266 * this byte range must be able to fit inside
267 * a single leaf so it will also fit inside a u32
269 diff = disk_bytenr - item_start_offset;
270 diff = diff / root->sectorsize;
271 diff = diff * csum_size;
273 read_extent_buffer(path->nodes[0], &sum,
274 ((unsigned long)item) + diff,
280 set_state_private(io_tree, offset, sum);
281 disk_bytenr += bvec->bv_len;
282 offset += bvec->bv_len;
286 btrfs_free_path(path);
290 int btrfs_lookup_bio_sums(struct btrfs_root *root, struct inode *inode,
291 struct bio *bio, u32 *dst)
293 return __btrfs_lookup_bio_sums(root, inode, bio, 0, dst, 0);
296 int btrfs_lookup_bio_sums_dio(struct btrfs_root *root, struct inode *inode,
297 struct bio *bio, u64 offset)
299 return __btrfs_lookup_bio_sums(root, inode, bio, offset, NULL, 1);
302 int btrfs_lookup_csums_range(struct btrfs_root *root, u64 start, u64 end,
303 struct list_head *list, int search_commit)
305 struct btrfs_key key;
306 struct btrfs_path *path;
307 struct extent_buffer *leaf;
308 struct btrfs_ordered_sum *sums;
309 struct btrfs_sector_sum *sector_sum;
310 struct btrfs_csum_item *item;
312 unsigned long offset;
316 u16 csum_size = btrfs_super_csum_size(root->fs_info->super_copy);
318 path = btrfs_alloc_path();
323 path->skip_locking = 1;
325 path->search_commit_root = 1;
328 key.objectid = BTRFS_EXTENT_CSUM_OBJECTID;
330 key.type = BTRFS_EXTENT_CSUM_KEY;
332 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
335 if (ret > 0 && path->slots[0] > 0) {
336 leaf = path->nodes[0];
337 btrfs_item_key_to_cpu(leaf, &key, path->slots[0] - 1);
338 if (key.objectid == BTRFS_EXTENT_CSUM_OBJECTID &&
339 key.type == BTRFS_EXTENT_CSUM_KEY) {
340 offset = (start - key.offset) >>
341 root->fs_info->sb->s_blocksize_bits;
342 if (offset * csum_size <
343 btrfs_item_size_nr(leaf, path->slots[0] - 1))
348 while (start <= end) {
349 leaf = path->nodes[0];
350 if (path->slots[0] >= btrfs_header_nritems(leaf)) {
351 ret = btrfs_next_leaf(root, path);
356 leaf = path->nodes[0];
359 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
360 if (key.objectid != BTRFS_EXTENT_CSUM_OBJECTID ||
361 key.type != BTRFS_EXTENT_CSUM_KEY)
364 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
365 if (key.offset > end)
368 if (key.offset > start)
371 size = btrfs_item_size_nr(leaf, path->slots[0]);
372 csum_end = key.offset + (size / csum_size) * root->sectorsize;
373 if (csum_end <= start) {
378 csum_end = min(csum_end, end + 1);
379 item = btrfs_item_ptr(path->nodes[0], path->slots[0],
380 struct btrfs_csum_item);
381 while (start < csum_end) {
382 size = min_t(size_t, csum_end - start,
383 MAX_ORDERED_SUM_BYTES(root));
384 sums = kzalloc(btrfs_ordered_sum_size(root, size),
391 sector_sum = sums->sums;
392 sums->bytenr = start;
395 offset = (start - key.offset) >>
396 root->fs_info->sb->s_blocksize_bits;
400 read_extent_buffer(path->nodes[0],
402 ((unsigned long)item) +
404 sector_sum->bytenr = start;
406 size -= root->sectorsize;
407 start += root->sectorsize;
411 list_add_tail(&sums->list, &tmplist);
417 while (ret < 0 && !list_empty(&tmplist)) {
418 sums = list_entry(&tmplist, struct btrfs_ordered_sum, list);
419 list_del(&sums->list);
422 list_splice_tail(&tmplist, list);
424 btrfs_free_path(path);
428 int btrfs_csum_one_bio(struct btrfs_root *root, struct inode *inode,
429 struct bio *bio, u64 file_start, int contig)
431 struct btrfs_ordered_sum *sums;
432 struct btrfs_sector_sum *sector_sum;
433 struct btrfs_ordered_extent *ordered;
435 struct bio_vec *bvec = bio->bi_io_vec;
437 unsigned long total_bytes = 0;
438 unsigned long this_sum_bytes = 0;
442 WARN_ON(bio->bi_vcnt <= 0);
443 sums = kzalloc(btrfs_ordered_sum_size(root, bio->bi_size), GFP_NOFS);
447 sector_sum = sums->sums;
448 disk_bytenr = (u64)bio->bi_sector << 9;
449 sums->len = bio->bi_size;
450 INIT_LIST_HEAD(&sums->list);
455 offset = page_offset(bvec->bv_page) + bvec->bv_offset;
457 ordered = btrfs_lookup_ordered_extent(inode, offset);
458 BUG_ON(!ordered); /* Logic error */
459 sums->bytenr = ordered->start;
461 while (bio_index < bio->bi_vcnt) {
463 offset = page_offset(bvec->bv_page) + bvec->bv_offset;
465 if (offset >= ordered->file_offset + ordered->len ||
466 offset < ordered->file_offset) {
467 unsigned long bytes_left;
468 sums->len = this_sum_bytes;
470 btrfs_add_ordered_sum(inode, ordered, sums);
471 btrfs_put_ordered_extent(ordered);
473 bytes_left = bio->bi_size - total_bytes;
475 sums = kzalloc(btrfs_ordered_sum_size(root, bytes_left),
477 BUG_ON(!sums); /* -ENOMEM */
478 sector_sum = sums->sums;
479 sums->len = bytes_left;
480 ordered = btrfs_lookup_ordered_extent(inode, offset);
481 BUG_ON(!ordered); /* Logic error */
482 sums->bytenr = ordered->start;
485 data = kmap_atomic(bvec->bv_page);
486 sector_sum->sum = ~(u32)0;
487 sector_sum->sum = btrfs_csum_data(root,
488 data + bvec->bv_offset,
492 btrfs_csum_final(sector_sum->sum,
493 (char *)§or_sum->sum);
494 sector_sum->bytenr = disk_bytenr;
498 total_bytes += bvec->bv_len;
499 this_sum_bytes += bvec->bv_len;
500 disk_bytenr += bvec->bv_len;
501 offset += bvec->bv_len;
505 btrfs_add_ordered_sum(inode, ordered, sums);
506 btrfs_put_ordered_extent(ordered);
511 * helper function for csum removal, this expects the
512 * key to describe the csum pointed to by the path, and it expects
513 * the csum to overlap the range [bytenr, len]
515 * The csum should not be entirely contained in the range and the
516 * range should not be entirely contained in the csum.
518 * This calls btrfs_truncate_item with the correct args based on the
519 * overlap, and fixes up the key as required.
521 static noinline void truncate_one_csum(struct btrfs_trans_handle *trans,
522 struct btrfs_root *root,
523 struct btrfs_path *path,
524 struct btrfs_key *key,
527 struct extent_buffer *leaf;
528 u16 csum_size = btrfs_super_csum_size(root->fs_info->super_copy);
530 u64 end_byte = bytenr + len;
531 u32 blocksize_bits = root->fs_info->sb->s_blocksize_bits;
533 leaf = path->nodes[0];
534 csum_end = btrfs_item_size_nr(leaf, path->slots[0]) / csum_size;
535 csum_end <<= root->fs_info->sb->s_blocksize_bits;
536 csum_end += key->offset;
538 if (key->offset < bytenr && csum_end <= end_byte) {
543 * A simple truncate off the end of the item
545 u32 new_size = (bytenr - key->offset) >> blocksize_bits;
546 new_size *= csum_size;
547 btrfs_truncate_item(trans, root, path, new_size, 1);
548 } else if (key->offset >= bytenr && csum_end > end_byte &&
549 end_byte > key->offset) {
554 * we need to truncate from the beginning of the csum
556 u32 new_size = (csum_end - end_byte) >> blocksize_bits;
557 new_size *= csum_size;
559 btrfs_truncate_item(trans, root, path, new_size, 0);
561 key->offset = end_byte;
562 btrfs_set_item_key_safe(trans, root, path, key);
569 * deletes the csum items from the csum tree for a given
572 int btrfs_del_csums(struct btrfs_trans_handle *trans,
573 struct btrfs_root *root, u64 bytenr, u64 len)
575 struct btrfs_path *path;
576 struct btrfs_key key;
577 u64 end_byte = bytenr + len;
579 struct extent_buffer *leaf;
581 u16 csum_size = btrfs_super_csum_size(root->fs_info->super_copy);
582 int blocksize_bits = root->fs_info->sb->s_blocksize_bits;
584 root = root->fs_info->csum_root;
586 path = btrfs_alloc_path();
591 key.objectid = BTRFS_EXTENT_CSUM_OBJECTID;
592 key.offset = end_byte - 1;
593 key.type = BTRFS_EXTENT_CSUM_KEY;
595 path->leave_spinning = 1;
596 ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
598 if (path->slots[0] == 0)
601 } else if (ret < 0) {
605 leaf = path->nodes[0];
606 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
608 if (key.objectid != BTRFS_EXTENT_CSUM_OBJECTID ||
609 key.type != BTRFS_EXTENT_CSUM_KEY) {
613 if (key.offset >= end_byte)
616 csum_end = btrfs_item_size_nr(leaf, path->slots[0]) / csum_size;
617 csum_end <<= blocksize_bits;
618 csum_end += key.offset;
620 /* this csum ends before we start, we're done */
621 if (csum_end <= bytenr)
624 /* delete the entire item, it is inside our range */
625 if (key.offset >= bytenr && csum_end <= end_byte) {
626 ret = btrfs_del_item(trans, root, path);
629 if (key.offset == bytenr)
631 } else if (key.offset < bytenr && csum_end > end_byte) {
632 unsigned long offset;
633 unsigned long shift_len;
634 unsigned long item_offset;
639 * Our bytes are in the middle of the csum,
640 * we need to split this item and insert a new one.
642 * But we can't drop the path because the
643 * csum could change, get removed, extended etc.
645 * The trick here is the max size of a csum item leaves
646 * enough room in the tree block for a single
647 * item header. So, we split the item in place,
648 * adding a new header pointing to the existing
649 * bytes. Then we loop around again and we have
650 * a nicely formed csum item that we can neatly
653 offset = (bytenr - key.offset) >> blocksize_bits;
656 shift_len = (len >> blocksize_bits) * csum_size;
658 item_offset = btrfs_item_ptr_offset(leaf,
661 memset_extent_buffer(leaf, 0, item_offset + offset,
666 * btrfs_split_item returns -EAGAIN when the
667 * item changed size or key
669 ret = btrfs_split_item(trans, root, path, &key, offset);
670 if (ret && ret != -EAGAIN) {
671 btrfs_abort_transaction(trans, root, ret);
675 key.offset = end_byte - 1;
677 truncate_one_csum(trans, root, path, &key, bytenr, len);
678 if (key.offset < bytenr)
681 btrfs_release_path(path);
685 btrfs_free_path(path);
689 static u64 btrfs_sector_sum_left(struct btrfs_ordered_sum *sums,
690 struct btrfs_sector_sum *sector_sum,
691 u64 total_bytes, u64 sectorsize)
693 u64 tmp = sectorsize;
694 u64 next_sector = sector_sum->bytenr;
695 struct btrfs_sector_sum *next = sector_sum + 1;
697 while ((tmp + total_bytes) < sums->len) {
698 if (next_sector + sectorsize != next->bytenr)
701 next_sector = next->bytenr;
707 int btrfs_csum_file_blocks(struct btrfs_trans_handle *trans,
708 struct btrfs_root *root,
709 struct btrfs_ordered_sum *sums)
713 struct btrfs_key file_key;
714 struct btrfs_key found_key;
718 struct btrfs_path *path;
719 struct btrfs_csum_item *item;
720 struct btrfs_csum_item *item_end;
721 struct extent_buffer *leaf = NULL;
723 struct btrfs_sector_sum *sector_sum;
726 u16 csum_size = btrfs_super_csum_size(root->fs_info->super_copy);
728 path = btrfs_alloc_path();
732 sector_sum = sums->sums;
734 next_offset = (u64)-1;
736 file_key.objectid = BTRFS_EXTENT_CSUM_OBJECTID;
737 file_key.offset = sector_sum->bytenr;
738 bytenr = sector_sum->bytenr;
739 btrfs_set_key_type(&file_key, BTRFS_EXTENT_CSUM_KEY);
741 item = btrfs_lookup_csum(trans, root, path, sector_sum->bytenr, 1);
743 leaf = path->nodes[0];
748 if (ret != -EFBIG && ret != -ENOENT)
753 /* we found one, but it isn't big enough yet */
754 leaf = path->nodes[0];
755 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
756 if ((item_size / csum_size) >=
757 MAX_CSUM_ITEMS(root, csum_size)) {
758 /* already at max size, make a new one */
762 int slot = path->slots[0] + 1;
763 /* we didn't find a csum item, insert one */
764 nritems = btrfs_header_nritems(path->nodes[0]);
765 if (path->slots[0] >= nritems - 1) {
766 ret = btrfs_next_leaf(root, path);
773 btrfs_item_key_to_cpu(path->nodes[0], &found_key, slot);
774 if (found_key.objectid != BTRFS_EXTENT_CSUM_OBJECTID ||
775 found_key.type != BTRFS_EXTENT_CSUM_KEY) {
779 next_offset = found_key.offset;
785 * at this point, we know the tree has an item, but it isn't big
786 * enough yet to put our csum in. Grow it
788 btrfs_release_path(path);
789 ret = btrfs_search_slot(trans, root, &file_key, path,
795 if (path->slots[0] == 0)
800 leaf = path->nodes[0];
801 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
802 csum_offset = (bytenr - found_key.offset) >>
803 root->fs_info->sb->s_blocksize_bits;
805 if (btrfs_key_type(&found_key) != BTRFS_EXTENT_CSUM_KEY ||
806 found_key.objectid != BTRFS_EXTENT_CSUM_OBJECTID ||
807 csum_offset >= MAX_CSUM_ITEMS(root, csum_size)) {
811 if (csum_offset == btrfs_item_size_nr(leaf, path->slots[0]) /
818 if (btrfs_leaf_free_space(root, leaf) <
819 sizeof(struct btrfs_item) + csum_size * 2)
822 free_space = btrfs_leaf_free_space(root, leaf) -
823 sizeof(struct btrfs_item) - csum_size;
824 tmp = btrfs_sector_sum_left(sums, sector_sum, total_bytes,
826 tmp >>= root->fs_info->sb->s_blocksize_bits;
829 extend_nr = max_t(int, 1, (int)tmp);
830 diff = (csum_offset + extend_nr) * csum_size;
831 diff = min(diff, MAX_CSUM_ITEMS(root, csum_size) * csum_size);
833 diff = diff - btrfs_item_size_nr(leaf, path->slots[0]);
834 diff = min(free_space, diff);
838 btrfs_extend_item(trans, root, path, diff);
843 btrfs_release_path(path);
848 tmp = btrfs_sector_sum_left(sums, sector_sum, total_bytes,
850 tmp >>= root->fs_info->sb->s_blocksize_bits;
851 tmp = min(tmp, (next_offset - file_key.offset) >>
852 root->fs_info->sb->s_blocksize_bits);
854 tmp = max((u64)1, tmp);
855 tmp = min(tmp, (u64)MAX_CSUM_ITEMS(root, csum_size));
856 ins_size = csum_size * tmp;
858 ins_size = csum_size;
860 path->leave_spinning = 1;
861 ret = btrfs_insert_empty_item(trans, root, path, &file_key,
863 path->leave_spinning = 0;
871 leaf = path->nodes[0];
872 item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_csum_item);
874 item = (struct btrfs_csum_item *)((unsigned char *)item +
875 csum_offset * csum_size);
877 item_end = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_csum_item);
878 item_end = (struct btrfs_csum_item *)((unsigned char *)item_end +
879 btrfs_item_size_nr(leaf, path->slots[0]));
882 write_extent_buffer(leaf, §or_sum->sum, (unsigned long)item, csum_size);
884 total_bytes += root->sectorsize;
886 if (total_bytes < sums->len) {
887 item = (struct btrfs_csum_item *)((char *)item +
889 if (item < item_end && bytenr + PAGE_CACHE_SIZE ==
890 sector_sum->bytenr) {
891 bytenr = sector_sum->bytenr;
896 btrfs_mark_buffer_dirty(path->nodes[0]);
897 if (total_bytes < sums->len) {
898 btrfs_release_path(path);
903 btrfs_free_path(path);