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Avoid beyond bounds copy while caching ACL
[zen-stable.git] / fs / btrfs / file-item.c
blobc7fb3a4247d3a766ab07cec511b6f0001e8f5e9f
1 /*
2 * Copyright (C) 2007 Oracle. All rights reserved.
3 *
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU General Public
6 * License v2 as published by the Free Software Foundation.
7 *
8 * This program is distributed in the hope that it will be useful,
9 * but WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
11 * General Public License for more details.
12 *
13 * You should have received a copy of the GNU General Public
14 * License along with this program; if not, write to the
15 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
16 * Boston, MA 021110-1307, USA.
17 */
18
19 #include <linux/bio.h>
20 #include <linux/slab.h>
21 #include <linux/pagemap.h>
22 #include <linux/highmem.h>
23 #include "ctree.h"
24 #include "disk-io.h"
25 #include "transaction.h"
26 #include "print-tree.h"
27
28 #define MAX_CSUM_ITEMS(r, size) ((((BTRFS_LEAF_DATA_SIZE(r) - \
29 sizeof(struct btrfs_item) * 2) / \
30 size) - 1))
31
32 #define MAX_ORDERED_SUM_BYTES(r) ((PAGE_SIZE - \
33 sizeof(struct btrfs_ordered_sum)) / \
34 sizeof(struct btrfs_sector_sum) * \
35 (r)->sectorsize - (r)->sectorsize)
36
37 int btrfs_insert_file_extent(struct btrfs_trans_handle *trans,
38 struct btrfs_root *root,
39 u64 objectid, u64 pos,
40 u64 disk_offset, u64 disk_num_bytes,
41 u64 num_bytes, u64 offset, u64 ram_bytes,
42 u8 compression, u8 encryption, u16 other_encoding)
43 {
44 int ret = 0;
45 struct btrfs_file_extent_item *item;
46 struct btrfs_key file_key;
47 struct btrfs_path *path;
48 struct extent_buffer *leaf;
49
50 path = btrfs_alloc_path();
51 if (!path)
52 return -ENOMEM;
53 file_key.objectid = objectid;
54 file_key.offset = pos;
55 btrfs_set_key_type(&file_key, BTRFS_EXTENT_DATA_KEY);
56
57 path->leave_spinning = 1;
58 ret = btrfs_insert_empty_item(trans, root, path, &file_key,
59 sizeof(*item));
60 if (ret < 0)
61 goto out;
62 BUG_ON(ret);
63 leaf = path->nodes[0];
64 item = btrfs_item_ptr(leaf, path->slots[0],
65 struct btrfs_file_extent_item);
66 btrfs_set_file_extent_disk_bytenr(leaf, item, disk_offset);
67 btrfs_set_file_extent_disk_num_bytes(leaf, item, disk_num_bytes);
68 btrfs_set_file_extent_offset(leaf, item, offset);
69 btrfs_set_file_extent_num_bytes(leaf, item, num_bytes);
70 btrfs_set_file_extent_ram_bytes(leaf, item, ram_bytes);
71 btrfs_set_file_extent_generation(leaf, item, trans->transid);
72 btrfs_set_file_extent_type(leaf, item, BTRFS_FILE_EXTENT_REG);
73 btrfs_set_file_extent_compression(leaf, item, compression);
74 btrfs_set_file_extent_encryption(leaf, item, encryption);
75 btrfs_set_file_extent_other_encoding(leaf, item, other_encoding);
76
77 btrfs_mark_buffer_dirty(leaf);
78 out:
79 btrfs_free_path(path);
80 return ret;
81 }
82
83 struct btrfs_csum_item *btrfs_lookup_csum(struct btrfs_trans_handle *trans,
84 struct btrfs_root *root,
85 struct btrfs_path *path,
86 u64 bytenr, int cow)
87 {
88 int ret;
89 struct btrfs_key file_key;
90 struct btrfs_key found_key;
91 struct btrfs_csum_item *item;
92 struct extent_buffer *leaf;
93 u64 csum_offset = 0;
94 u16 csum_size = btrfs_super_csum_size(root->fs_info->super_copy);
95 int csums_in_item;
96
97 file_key.objectid = BTRFS_EXTENT_CSUM_OBJECTID;
98 file_key.offset = bytenr;
99 btrfs_set_key_type(&file_key, BTRFS_EXTENT_CSUM_KEY);
100 ret = btrfs_search_slot(trans, root, &file_key, path, 0, cow);
101 if (ret < 0)
102 goto fail;
103 leaf = path->nodes[0];
104 if (ret > 0) {
105 ret = 1;
106 if (path->slots[0] == 0)
107 goto fail;
108 path->slots[0]--;
109 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
110 if (btrfs_key_type(&found_key) != BTRFS_EXTENT_CSUM_KEY)
111 goto fail;
112
113 csum_offset = (bytenr - found_key.offset) >>
114 root->fs_info->sb->s_blocksize_bits;
115 csums_in_item = btrfs_item_size_nr(leaf, path->slots[0]);
116 csums_in_item /= csum_size;
117
118 if (csum_offset >= csums_in_item) {
119 ret = -EFBIG;
120 goto fail;
121 }
122 }
123 item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_csum_item);
124 item = (struct btrfs_csum_item *)((unsigned char *)item +
125 csum_offset * csum_size);
126 return item;
127 fail:
128 if (ret > 0)
129 ret = -ENOENT;
130 return ERR_PTR(ret);
131 }
132
133
134 int btrfs_lookup_file_extent(struct btrfs_trans_handle *trans,
135 struct btrfs_root *root,
136 struct btrfs_path *path, u64 objectid,
137 u64 offset, int mod)
138 {
139 int ret;
140 struct btrfs_key file_key;
141 int ins_len = mod < 0 ? -1 : 0;
142 int cow = mod != 0;
143
144 file_key.objectid = objectid;
145 file_key.offset = offset;
146 btrfs_set_key_type(&file_key, BTRFS_EXTENT_DATA_KEY);
147 ret = btrfs_search_slot(trans, root, &file_key, path, ins_len, cow);
148 return ret;
149 }
150
151
152 static int __btrfs_lookup_bio_sums(struct btrfs_root *root,
153 struct inode *inode, struct bio *bio,
154 u64 logical_offset, u32 *dst, int dio)
155 {
156 u32 sum;
157 struct bio_vec *bvec = bio->bi_io_vec;
158 int bio_index = 0;
159 u64 offset = 0;
160 u64 item_start_offset = 0;
161 u64 item_last_offset = 0;
162 u64 disk_bytenr;
163 u32 diff;
164 u16 csum_size = btrfs_super_csum_size(root->fs_info->super_copy);
165 int ret;
166 struct btrfs_path *path;
167 struct btrfs_csum_item *item = NULL;
168 struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
169
170 path = btrfs_alloc_path();
171 if (!path)
172 return -ENOMEM;
173 if (bio->bi_size > PAGE_CACHE_SIZE * 8)
174 path->reada = 2;
175
176 WARN_ON(bio->bi_vcnt <= 0);
177
178 /*
179 * the free space stuff is only read when it hasn't been
180 * updated in the current transaction. So, we can safely
181 * read from the commit root and sidestep a nasty deadlock
182 * between reading the free space cache and updating the csum tree.
183 */
184 if (btrfs_is_free_space_inode(root, inode)) {
185 path->search_commit_root = 1;
186 path->skip_locking = 1;
187 }
188
189 disk_bytenr = (u64)bio->bi_sector << 9;
190 if (dio)
191 offset = logical_offset;
192 while (bio_index < bio->bi_vcnt) {
193 if (!dio)
194 offset = page_offset(bvec->bv_page) + bvec->bv_offset;
195 ret = btrfs_find_ordered_sum(inode, offset, disk_bytenr, &sum);
196 if (ret == 0)
197 goto found;
198
199 if (!item || disk_bytenr < item_start_offset ||
200 disk_bytenr >= item_last_offset) {
201 struct btrfs_key found_key;
202 u32 item_size;
203
204 if (item)
205 btrfs_release_path(path);
206 item = btrfs_lookup_csum(NULL, root->fs_info->csum_root,
207 path, disk_bytenr, 0);
208 if (IS_ERR(item)) {
209 ret = PTR_ERR(item);
210 if (ret == -ENOENT || ret == -EFBIG)
211 ret = 0;
212 sum = 0;
213 if (BTRFS_I(inode)->root->root_key.objectid ==
214 BTRFS_DATA_RELOC_TREE_OBJECTID) {
215 set_extent_bits(io_tree, offset,
216 offset + bvec->bv_len - 1,
217 EXTENT_NODATASUM, GFP_NOFS);
218 } else {
219 printk(KERN_INFO "btrfs no csum found "
220 "for inode %llu start %llu\n",
221 (unsigned long long)
222 btrfs_ino(inode),
223 (unsigned long long)offset);
224 }
225 item = NULL;
226 btrfs_release_path(path);
227 goto found;
228 }
229 btrfs_item_key_to_cpu(path->nodes[0], &found_key,
230 path->slots[0]);
231
232 item_start_offset = found_key.offset;
233 item_size = btrfs_item_size_nr(path->nodes[0],
234 path->slots[0]);
235 item_last_offset = item_start_offset +
236 (item_size / csum_size) *
237 root->sectorsize;
238 item = btrfs_item_ptr(path->nodes[0], path->slots[0],
239 struct btrfs_csum_item);
240 }
241 /*
242 * this byte range must be able to fit inside
243 * a single leaf so it will also fit inside a u32
244 */
245 diff = disk_bytenr - item_start_offset;
246 diff = diff / root->sectorsize;
247 diff = diff * csum_size;
248
249 read_extent_buffer(path->nodes[0], &sum,
250 ((unsigned long)item) + diff,
251 csum_size);
252 found:
253 if (dst)
254 *dst++ = sum;
255 else
256 set_state_private(io_tree, offset, sum);
257 disk_bytenr += bvec->bv_len;
258 offset += bvec->bv_len;
259 bio_index++;
260 bvec++;
261 }
262 btrfs_free_path(path);
263 return 0;
264 }
265
266 int btrfs_lookup_bio_sums(struct btrfs_root *root, struct inode *inode,
267 struct bio *bio, u32 *dst)
268 {
269 return __btrfs_lookup_bio_sums(root, inode, bio, 0, dst, 0);
270 }
271
272 int btrfs_lookup_bio_sums_dio(struct btrfs_root *root, struct inode *inode,
273 struct bio *bio, u64 offset, u32 *dst)
274 {
275 return __btrfs_lookup_bio_sums(root, inode, bio, offset, dst, 1);
276 }
277
278 int btrfs_lookup_csums_range(struct btrfs_root *root, u64 start, u64 end,
279 struct list_head *list, int search_commit)
280 {
281 struct btrfs_key key;
282 struct btrfs_path *path;
283 struct extent_buffer *leaf;
284 struct btrfs_ordered_sum *sums;
285 struct btrfs_sector_sum *sector_sum;
286 struct btrfs_csum_item *item;
287 unsigned long offset;
288 int ret;
289 size_t size;
290 u64 csum_end;
291 u16 csum_size = btrfs_super_csum_size(root->fs_info->super_copy);
292
293 path = btrfs_alloc_path();
294 if (!path)
295 return -ENOMEM;
296
297 if (search_commit) {
298 path->skip_locking = 1;
299 path->reada = 2;
300 path->search_commit_root = 1;
301 }
302
303 key.objectid = BTRFS_EXTENT_CSUM_OBJECTID;
304 key.offset = start;
305 key.type = BTRFS_EXTENT_CSUM_KEY;
306
307 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
308 if (ret < 0)
309 goto fail;
310 if (ret > 0 && path->slots[0] > 0) {
311 leaf = path->nodes[0];
312 btrfs_item_key_to_cpu(leaf, &key, path->slots[0] - 1);
313 if (key.objectid == BTRFS_EXTENT_CSUM_OBJECTID &&
314 key.type == BTRFS_EXTENT_CSUM_KEY) {
315 offset = (start - key.offset) >>
316 root->fs_info->sb->s_blocksize_bits;
317 if (offset * csum_size <
318 btrfs_item_size_nr(leaf, path->slots[0] - 1))
319 path->slots[0]--;
320 }
321 }
322
323 while (start <= end) {
324 leaf = path->nodes[0];
325 if (path->slots[0] >= btrfs_header_nritems(leaf)) {
326 ret = btrfs_next_leaf(root, path);
327 if (ret < 0)
328 goto fail;
329 if (ret > 0)
330 break;
331 leaf = path->nodes[0];
332 }
333
334 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
335 if (key.objectid != BTRFS_EXTENT_CSUM_OBJECTID ||
336 key.type != BTRFS_EXTENT_CSUM_KEY)
337 break;
338
339 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
340 if (key.offset > end)
341 break;
342
343 if (key.offset > start)
344 start = key.offset;
345
346 size = btrfs_item_size_nr(leaf, path->slots[0]);
347 csum_end = key.offset + (size / csum_size) * root->sectorsize;
348 if (csum_end <= start) {
349 path->slots[0]++;
350 continue;
351 }
352
353 csum_end = min(csum_end, end + 1);
354 item = btrfs_item_ptr(path->nodes[0], path->slots[0],
355 struct btrfs_csum_item);
356 while (start < csum_end) {
357 size = min_t(size_t, csum_end - start,
358 MAX_ORDERED_SUM_BYTES(root));
359 sums = kzalloc(btrfs_ordered_sum_size(root, size),
360 GFP_NOFS);
361 BUG_ON(!sums);
362
363 sector_sum = sums->sums;
364 sums->bytenr = start;
365 sums->len = size;
366
367 offset = (start - key.offset) >>
368 root->fs_info->sb->s_blocksize_bits;
369 offset *= csum_size;
370
371 while (size > 0) {
372 read_extent_buffer(path->nodes[0],
373 &sector_sum->sum,
374 ((unsigned long)item) +
375 offset, csum_size);
376 sector_sum->bytenr = start;
377
378 size -= root->sectorsize;
379 start += root->sectorsize;
380 offset += csum_size;
381 sector_sum++;
382 }
383 list_add_tail(&sums->list, list);
384 }
385 path->slots[0]++;
386 }
387 ret = 0;
388 fail:
389 btrfs_free_path(path);
390 return ret;
391 }
392
393 int btrfs_csum_one_bio(struct btrfs_root *root, struct inode *inode,
394 struct bio *bio, u64 file_start, int contig)
395 {
396 struct btrfs_ordered_sum *sums;
397 struct btrfs_sector_sum *sector_sum;
398 struct btrfs_ordered_extent *ordered;
399 char *data;
400 struct bio_vec *bvec = bio->bi_io_vec;
401 int bio_index = 0;
402 unsigned long total_bytes = 0;
403 unsigned long this_sum_bytes = 0;
404 u64 offset;
405 u64 disk_bytenr;
406
407 WARN_ON(bio->bi_vcnt <= 0);
408 sums = kzalloc(btrfs_ordered_sum_size(root, bio->bi_size), GFP_NOFS);
409 if (!sums)
410 return -ENOMEM;
411
412 sector_sum = sums->sums;
413 disk_bytenr = (u64)bio->bi_sector << 9;
414 sums->len = bio->bi_size;
415 INIT_LIST_HEAD(&sums->list);
416
417 if (contig)
418 offset = file_start;
419 else
420 offset = page_offset(bvec->bv_page) + bvec->bv_offset;
421
422 ordered = btrfs_lookup_ordered_extent(inode, offset);
423 BUG_ON(!ordered);
424 sums->bytenr = ordered->start;
425
426 while (bio_index < bio->bi_vcnt) {
427 if (!contig)
428 offset = page_offset(bvec->bv_page) + bvec->bv_offset;
429
430 if (!contig && (offset >= ordered->file_offset + ordered->len ||
431 offset < ordered->file_offset)) {
432 unsigned long bytes_left;
433 sums->len = this_sum_bytes;
434 this_sum_bytes = 0;
435 btrfs_add_ordered_sum(inode, ordered, sums);
436 btrfs_put_ordered_extent(ordered);
437
438 bytes_left = bio->bi_size - total_bytes;
439
440 sums = kzalloc(btrfs_ordered_sum_size(root, bytes_left),
441 GFP_NOFS);
442 BUG_ON(!sums);
443 sector_sum = sums->sums;
444 sums->len = bytes_left;
445 ordered = btrfs_lookup_ordered_extent(inode, offset);
446 BUG_ON(!ordered);
447 sums->bytenr = ordered->start;
448 }
449
450 data = kmap_atomic(bvec->bv_page, KM_USER0);
451 sector_sum->sum = ~(u32)0;
452 sector_sum->sum = btrfs_csum_data(root,
453 data + bvec->bv_offset,
454 sector_sum->sum,
455 bvec->bv_len);
456 kunmap_atomic(data, KM_USER0);
457 btrfs_csum_final(sector_sum->sum,
458 (char *)&sector_sum->sum);
459 sector_sum->bytenr = disk_bytenr;
460
461 sector_sum++;
462 bio_index++;
463 total_bytes += bvec->bv_len;
464 this_sum_bytes += bvec->bv_len;
465 disk_bytenr += bvec->bv_len;
466 offset += bvec->bv_len;
467 bvec++;
468 }
469 this_sum_bytes = 0;
470 btrfs_add_ordered_sum(inode, ordered, sums);
471 btrfs_put_ordered_extent(ordered);
472 return 0;
473 }
474
475 /*
476 * helper function for csum removal, this expects the
477 * key to describe the csum pointed to by the path, and it expects
478 * the csum to overlap the range [bytenr, len]
479 *
480 * The csum should not be entirely contained in the range and the
481 * range should not be entirely contained in the csum.
482 *
483 * This calls btrfs_truncate_item with the correct args based on the
484 * overlap, and fixes up the key as required.
485 */
486 static noinline int truncate_one_csum(struct btrfs_trans_handle *trans,
487 struct btrfs_root *root,
488 struct btrfs_path *path,
489 struct btrfs_key *key,
490 u64 bytenr, u64 len)
491 {
492 struct extent_buffer *leaf;
493 u16 csum_size = btrfs_super_csum_size(root->fs_info->super_copy);
494 u64 csum_end;
495 u64 end_byte = bytenr + len;
496 u32 blocksize_bits = root->fs_info->sb->s_blocksize_bits;
497 int ret;
498
499 leaf = path->nodes[0];
500 csum_end = btrfs_item_size_nr(leaf, path->slots[0]) / csum_size;
501 csum_end <<= root->fs_info->sb->s_blocksize_bits;
502 csum_end += key->offset;
503
504 if (key->offset < bytenr && csum_end <= end_byte) {
505 /*
506 * [ bytenr - len ]
507 * [ ]
508 * [csum ]
509 * A simple truncate off the end of the item
510 */
511 u32 new_size = (bytenr - key->offset) >> blocksize_bits;
512 new_size *= csum_size;
513 ret = btrfs_truncate_item(trans, root, path, new_size, 1);
514 } else if (key->offset >= bytenr && csum_end > end_byte &&
515 end_byte > key->offset) {
516 /*
517 * [ bytenr - len ]
518 * [ ]
519 * [csum ]
520 * we need to truncate from the beginning of the csum
521 */
522 u32 new_size = (csum_end - end_byte) >> blocksize_bits;
523 new_size *= csum_size;
524
525 ret = btrfs_truncate_item(trans, root, path, new_size, 0);
526
527 key->offset = end_byte;
528 ret = btrfs_set_item_key_safe(trans, root, path, key);
529 BUG_ON(ret);
530 } else {
531 BUG();
532 }
533 return 0;
534 }
535
536 /*
537 * deletes the csum items from the csum tree for a given
538 * range of bytes.
539 */
540 int btrfs_del_csums(struct btrfs_trans_handle *trans,
541 struct btrfs_root *root, u64 bytenr, u64 len)
542 {
543 struct btrfs_path *path;
544 struct btrfs_key key;
545 u64 end_byte = bytenr + len;
546 u64 csum_end;
547 struct extent_buffer *leaf;
548 int ret;
549 u16 csum_size = btrfs_super_csum_size(root->fs_info->super_copy);
550 int blocksize_bits = root->fs_info->sb->s_blocksize_bits;
551
552 root = root->fs_info->csum_root;
553
554 path = btrfs_alloc_path();
555 if (!path)
556 return -ENOMEM;
557
558 while (1) {
559 key.objectid = BTRFS_EXTENT_CSUM_OBJECTID;
560 key.offset = end_byte - 1;
561 key.type = BTRFS_EXTENT_CSUM_KEY;
562
563 path->leave_spinning = 1;
564 ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
565 if (ret > 0) {
566 if (path->slots[0] == 0)
567 break;
568 path->slots[0]--;
569 } else if (ret < 0) {
570 break;
571 }
572
573 leaf = path->nodes[0];
574 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
575
576 if (key.objectid != BTRFS_EXTENT_CSUM_OBJECTID ||
577 key.type != BTRFS_EXTENT_CSUM_KEY) {
578 break;
579 }
580
581 if (key.offset >= end_byte)
582 break;
583
584 csum_end = btrfs_item_size_nr(leaf, path->slots[0]) / csum_size;
585 csum_end <<= blocksize_bits;
586 csum_end += key.offset;
587
588 /* this csum ends before we start, we're done */
589 if (csum_end <= bytenr)
590 break;
591
592 /* delete the entire item, it is inside our range */
593 if (key.offset >= bytenr && csum_end <= end_byte) {
594 ret = btrfs_del_item(trans, root, path);
595 if (ret)
596 goto out;
597 if (key.offset == bytenr)
598 break;
599 } else if (key.offset < bytenr && csum_end > end_byte) {
600 unsigned long offset;
601 unsigned long shift_len;
602 unsigned long item_offset;
603 /*
604 * [ bytenr - len ]
605 * [csum ]
606 *
607 * Our bytes are in the middle of the csum,
608 * we need to split this item and insert a new one.
609 *
610 * But we can't drop the path because the
611 * csum could change, get removed, extended etc.
612 *
613 * The trick here is the max size of a csum item leaves
614 * enough room in the tree block for a single
615 * item header. So, we split the item in place,
616 * adding a new header pointing to the existing
617 * bytes. Then we loop around again and we have
618 * a nicely formed csum item that we can neatly
619 * truncate.
620 */
621 offset = (bytenr - key.offset) >> blocksize_bits;
622 offset *= csum_size;
623
624 shift_len = (len >> blocksize_bits) * csum_size;
625
626 item_offset = btrfs_item_ptr_offset(leaf,
627 path->slots[0]);
628
629 memset_extent_buffer(leaf, 0, item_offset + offset,
630 shift_len);
631 key.offset = bytenr;
632
633 /*
634 * btrfs_split_item returns -EAGAIN when the
635 * item changed size or key
636 */
637 ret = btrfs_split_item(trans, root, path, &key, offset);
638 BUG_ON(ret && ret != -EAGAIN);
639
640 key.offset = end_byte - 1;
641 } else {
642 ret = truncate_one_csum(trans, root, path,
643 &key, bytenr, len);
644 BUG_ON(ret);
645 if (key.offset < bytenr)
646 break;
647 }
648 btrfs_release_path(path);
649 }
650 ret = 0;
651 out:
652 btrfs_free_path(path);
653 return ret;
654 }
655
656 int btrfs_csum_file_blocks(struct btrfs_trans_handle *trans,
657 struct btrfs_root *root,
658 struct btrfs_ordered_sum *sums)
659 {
660 u64 bytenr;
661 int ret;
662 struct btrfs_key file_key;
663 struct btrfs_key found_key;
664 u64 next_offset;
665 u64 total_bytes = 0;
666 int found_next;
667 struct btrfs_path *path;
668 struct btrfs_csum_item *item;
669 struct btrfs_csum_item *item_end;
670 struct extent_buffer *leaf = NULL;
671 u64 csum_offset;
672 struct btrfs_sector_sum *sector_sum;
673 u32 nritems;
674 u32 ins_size;
675 u16 csum_size = btrfs_super_csum_size(root->fs_info->super_copy);
676
677 path = btrfs_alloc_path();
678 if (!path)
679 return -ENOMEM;
680
681 sector_sum = sums->sums;
682 again:
683 next_offset = (u64)-1;
684 found_next = 0;
685 file_key.objectid = BTRFS_EXTENT_CSUM_OBJECTID;
686 file_key.offset = sector_sum->bytenr;
687 bytenr = sector_sum->bytenr;
688 btrfs_set_key_type(&file_key, BTRFS_EXTENT_CSUM_KEY);
689
690 item = btrfs_lookup_csum(trans, root, path, sector_sum->bytenr, 1);
691 if (!IS_ERR(item)) {
692 leaf = path->nodes[0];
693 ret = 0;
694 goto found;
695 }
696 ret = PTR_ERR(item);
697 if (ret != -EFBIG && ret != -ENOENT)
698 goto fail_unlock;
699
700 if (ret == -EFBIG) {
701 u32 item_size;
702 /* we found one, but it isn't big enough yet */
703 leaf = path->nodes[0];
704 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
705 if ((item_size / csum_size) >=
706 MAX_CSUM_ITEMS(root, csum_size)) {
707 /* already at max size, make a new one */
708 goto insert;
709 }
710 } else {
711 int slot = path->slots[0] + 1;
712 /* we didn't find a csum item, insert one */
713 nritems = btrfs_header_nritems(path->nodes[0]);
714 if (path->slots[0] >= nritems - 1) {
715 ret = btrfs_next_leaf(root, path);
716 if (ret == 1)
717 found_next = 1;
718 if (ret != 0)
719 goto insert;
720 slot = 0;
721 }
722 btrfs_item_key_to_cpu(path->nodes[0], &found_key, slot);
723 if (found_key.objectid != BTRFS_EXTENT_CSUM_OBJECTID ||
724 found_key.type != BTRFS_EXTENT_CSUM_KEY) {
725 found_next = 1;
726 goto insert;
727 }
728 next_offset = found_key.offset;
729 found_next = 1;
730 goto insert;
731 }
732
733 /*
734 * at this point, we know the tree has an item, but it isn't big
735 * enough yet to put our csum in. Grow it
736 */
737 btrfs_release_path(path);
738 ret = btrfs_search_slot(trans, root, &file_key, path,
739 csum_size, 1);
740 if (ret < 0)
741 goto fail_unlock;
742
743 if (ret > 0) {
744 if (path->slots[0] == 0)
745 goto insert;
746 path->slots[0]--;
747 }
748
749 leaf = path->nodes[0];
750 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
751 csum_offset = (bytenr - found_key.offset) >>
752 root->fs_info->sb->s_blocksize_bits;
753
754 if (btrfs_key_type(&found_key) != BTRFS_EXTENT_CSUM_KEY ||
755 found_key.objectid != BTRFS_EXTENT_CSUM_OBJECTID ||
756 csum_offset >= MAX_CSUM_ITEMS(root, csum_size)) {
757 goto insert;
758 }
759
760 if (csum_offset >= btrfs_item_size_nr(leaf, path->slots[0]) /
761 csum_size) {
762 u32 diff = (csum_offset + 1) * csum_size;
763
764 /*
765 * is the item big enough already? we dropped our lock
766 * before and need to recheck
767 */
768 if (diff < btrfs_item_size_nr(leaf, path->slots[0]))
769 goto csum;
770
771 diff = diff - btrfs_item_size_nr(leaf, path->slots[0]);
772 if (diff != csum_size)
773 goto insert;
774
775 ret = btrfs_extend_item(trans, root, path, diff);
776 goto csum;
777 }
778
779 insert:
780 btrfs_release_path(path);
781 csum_offset = 0;
782 if (found_next) {
783 u64 tmp = total_bytes + root->sectorsize;
784 u64 next_sector = sector_sum->bytenr;
785 struct btrfs_sector_sum *next = sector_sum + 1;
786
787 while (tmp < sums->len) {
788 if (next_sector + root->sectorsize != next->bytenr)
789 break;
790 tmp += root->sectorsize;
791 next_sector = next->bytenr;
792 next++;
793 }
794 tmp = min(tmp, next_offset - file_key.offset);
795 tmp >>= root->fs_info->sb->s_blocksize_bits;
796 tmp = max((u64)1, tmp);
797 tmp = min(tmp, (u64)MAX_CSUM_ITEMS(root, csum_size));
798 ins_size = csum_size * tmp;
799 } else {
800 ins_size = csum_size;
801 }
802 path->leave_spinning = 1;
803 ret = btrfs_insert_empty_item(trans, root, path, &file_key,
804 ins_size);
805 path->leave_spinning = 0;
806 if (ret < 0)
807 goto fail_unlock;
808 if (ret != 0) {
809 WARN_ON(1);
810 goto fail_unlock;
811 }
812 csum:
813 leaf = path->nodes[0];
814 item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_csum_item);
815 ret = 0;
816 item = (struct btrfs_csum_item *)((unsigned char *)item +
817 csum_offset * csum_size);
818 found:
819 item_end = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_csum_item);
820 item_end = (struct btrfs_csum_item *)((unsigned char *)item_end +
821 btrfs_item_size_nr(leaf, path->slots[0]));
822 next_sector:
823
824 write_extent_buffer(leaf, &sector_sum->sum, (unsigned long)item, csum_size);
825
826 total_bytes += root->sectorsize;
827 sector_sum++;
828 if (total_bytes < sums->len) {
829 item = (struct btrfs_csum_item *)((char *)item +
830 csum_size);
831 if (item < item_end && bytenr + PAGE_CACHE_SIZE ==
832 sector_sum->bytenr) {
833 bytenr = sector_sum->bytenr;
834 goto next_sector;
835 }
836 }
837
838 btrfs_mark_buffer_dirty(path->nodes[0]);
839 if (total_bytes < sums->len) {
840 btrfs_release_path(path);
841 cond_resched();
842 goto again;
843 }
844 out:
845 btrfs_free_path(path);
846 return ret;
847
848 fail_unlock:
849 goto out;
850 }