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btrfs: don't BUG_ON btrfs_alloc_path() errors
[deliverable/linux.git] / fs / btrfs / file-item.c
1 /*
2 * Copyright (C) 2007 Oracle. All rights reserved.
3 *
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU General Public
6 * License v2 as published by the Free Software Foundation.
7 *
8 * This program is distributed in the hope that it will be useful,
9 * but WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
11 * General Public License for more details.
12 *
13 * You should have received a copy of the GNU General Public
14 * License along with this program; if not, write to the
15 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
16 * Boston, MA 021110-1307, USA.
17 */
18
19 #include <linux/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 =
95 btrfs_super_csum_size(&root->fs_info->super_copy);
96 int csums_in_item;
97
98 file_key.objectid = BTRFS_EXTENT_CSUM_OBJECTID;
99 file_key.offset = bytenr;
100 btrfs_set_key_type(&file_key, BTRFS_EXTENT_CSUM_KEY);
101 ret = btrfs_search_slot(trans, root, &file_key, path, 0, cow);
102 if (ret < 0)
103 goto fail;
104 leaf = path->nodes[0];
105 if (ret > 0) {
106 ret = 1;
107 if (path->slots[0] == 0)
108 goto fail;
109 path->slots[0]--;
110 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
111 if (btrfs_key_type(&found_key) != BTRFS_EXTENT_CSUM_KEY)
112 goto fail;
113
114 csum_offset = (bytenr - found_key.offset) >>
115 root->fs_info->sb->s_blocksize_bits;
116 csums_in_item = btrfs_item_size_nr(leaf, path->slots[0]);
117 csums_in_item /= csum_size;
118
119 if (csum_offset >= csums_in_item) {
120 ret = -EFBIG;
121 goto fail;
122 }
123 }
124 item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_csum_item);
125 item = (struct btrfs_csum_item *)((unsigned char *)item +
126 csum_offset * csum_size);
127 return item;
128 fail:
129 if (ret > 0)
130 ret = -ENOENT;
131 return ERR_PTR(ret);
132 }
133
134
135 int btrfs_lookup_file_extent(struct btrfs_trans_handle *trans,
136 struct btrfs_root *root,
137 struct btrfs_path *path, u64 objectid,
138 u64 offset, int mod)
139 {
140 int ret;
141 struct btrfs_key file_key;
142 int ins_len = mod < 0 ? -1 : 0;
143 int cow = mod != 0;
144
145 file_key.objectid = objectid;
146 file_key.offset = offset;
147 btrfs_set_key_type(&file_key, BTRFS_EXTENT_DATA_KEY);
148 ret = btrfs_search_slot(trans, root, &file_key, path, ins_len, cow);
149 return ret;
150 }
151
152
153 static int __btrfs_lookup_bio_sums(struct btrfs_root *root,
154 struct inode *inode, struct bio *bio,
155 u64 logical_offset, u32 *dst, int dio)
156 {
157 u32 sum;
158 struct bio_vec *bvec = bio->bi_io_vec;
159 int bio_index = 0;
160 u64 offset = 0;
161 u64 item_start_offset = 0;
162 u64 item_last_offset = 0;
163 u64 disk_bytenr;
164 u32 diff;
165 u16 csum_size =
166 btrfs_super_csum_size(&root->fs_info->super_copy);
167 int ret;
168 struct btrfs_path *path;
169 struct btrfs_csum_item *item = NULL;
170 struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
171
172 path = btrfs_alloc_path();
173 if (!path)
174 return -ENOMEM;
175 if (bio->bi_size > PAGE_CACHE_SIZE * 8)
176 path->reada = 2;
177
178 WARN_ON(bio->bi_vcnt <= 0);
179
180 disk_bytenr = (u64)bio->bi_sector << 9;
181 if (dio)
182 offset = logical_offset;
183 while (bio_index < bio->bi_vcnt) {
184 if (!dio)
185 offset = page_offset(bvec->bv_page) + bvec->bv_offset;
186 ret = btrfs_find_ordered_sum(inode, offset, disk_bytenr, &sum);
187 if (ret == 0)
188 goto found;
189
190 if (!item || disk_bytenr < item_start_offset ||
191 disk_bytenr >= item_last_offset) {
192 struct btrfs_key found_key;
193 u32 item_size;
194
195 if (item)
196 btrfs_release_path(path);
197 item = btrfs_lookup_csum(NULL, root->fs_info->csum_root,
198 path, disk_bytenr, 0);
199 if (IS_ERR(item)) {
200 ret = PTR_ERR(item);
201 if (ret == -ENOENT || ret == -EFBIG)
202 ret = 0;
203 sum = 0;
204 if (BTRFS_I(inode)->root->root_key.objectid ==
205 BTRFS_DATA_RELOC_TREE_OBJECTID) {
206 set_extent_bits(io_tree, offset,
207 offset + bvec->bv_len - 1,
208 EXTENT_NODATASUM, GFP_NOFS);
209 } else {
210 printk(KERN_INFO "btrfs no csum found "
211 "for inode %llu start %llu\n",
212 (unsigned long long)
213 btrfs_ino(inode),
214 (unsigned long long)offset);
215 }
216 item = NULL;
217 btrfs_release_path(path);
218 goto found;
219 }
220 btrfs_item_key_to_cpu(path->nodes[0], &found_key,
221 path->slots[0]);
222
223 item_start_offset = found_key.offset;
224 item_size = btrfs_item_size_nr(path->nodes[0],
225 path->slots[0]);
226 item_last_offset = item_start_offset +
227 (item_size / csum_size) *
228 root->sectorsize;
229 item = btrfs_item_ptr(path->nodes[0], path->slots[0],
230 struct btrfs_csum_item);
231 }
232 /*
233 * this byte range must be able to fit inside
234 * a single leaf so it will also fit inside a u32
235 */
236 diff = disk_bytenr - item_start_offset;
237 diff = diff / root->sectorsize;
238 diff = diff * csum_size;
239
240 read_extent_buffer(path->nodes[0], &sum,
241 ((unsigned long)item) + diff,
242 csum_size);
243 found:
244 if (dst)
245 *dst++ = sum;
246 else
247 set_state_private(io_tree, offset, sum);
248 disk_bytenr += bvec->bv_len;
249 offset += bvec->bv_len;
250 bio_index++;
251 bvec++;
252 }
253 btrfs_free_path(path);
254 return 0;
255 }
256
257 int btrfs_lookup_bio_sums(struct btrfs_root *root, struct inode *inode,
258 struct bio *bio, u32 *dst)
259 {
260 return __btrfs_lookup_bio_sums(root, inode, bio, 0, dst, 0);
261 }
262
263 int btrfs_lookup_bio_sums_dio(struct btrfs_root *root, struct inode *inode,
264 struct bio *bio, u64 offset, u32 *dst)
265 {
266 return __btrfs_lookup_bio_sums(root, inode, bio, offset, dst, 1);
267 }
268
269 int btrfs_lookup_csums_range(struct btrfs_root *root, u64 start, u64 end,
270 struct list_head *list, int search_commit)
271 {
272 struct btrfs_key key;
273 struct btrfs_path *path;
274 struct extent_buffer *leaf;
275 struct btrfs_ordered_sum *sums;
276 struct btrfs_sector_sum *sector_sum;
277 struct btrfs_csum_item *item;
278 unsigned long offset;
279 int ret;
280 size_t size;
281 u64 csum_end;
282 u16 csum_size = btrfs_super_csum_size(&root->fs_info->super_copy);
283
284 path = btrfs_alloc_path();
285 if (!path)
286 return -ENOMEM;
287
288 if (search_commit) {
289 path->skip_locking = 1;
290 path->reada = 2;
291 path->search_commit_root = 1;
292 }
293
294 key.objectid = BTRFS_EXTENT_CSUM_OBJECTID;
295 key.offset = start;
296 key.type = BTRFS_EXTENT_CSUM_KEY;
297
298 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
299 if (ret < 0)
300 goto fail;
301 if (ret > 0 && path->slots[0] > 0) {
302 leaf = path->nodes[0];
303 btrfs_item_key_to_cpu(leaf, &key, path->slots[0] - 1);
304 if (key.objectid == BTRFS_EXTENT_CSUM_OBJECTID &&
305 key.type == BTRFS_EXTENT_CSUM_KEY) {
306 offset = (start - key.offset) >>
307 root->fs_info->sb->s_blocksize_bits;
308 if (offset * csum_size <
309 btrfs_item_size_nr(leaf, path->slots[0] - 1))
310 path->slots[0]--;
311 }
312 }
313
314 while (start <= end) {
315 leaf = path->nodes[0];
316 if (path->slots[0] >= btrfs_header_nritems(leaf)) {
317 ret = btrfs_next_leaf(root, path);
318 if (ret < 0)
319 goto fail;
320 if (ret > 0)
321 break;
322 leaf = path->nodes[0];
323 }
324
325 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
326 if (key.objectid != BTRFS_EXTENT_CSUM_OBJECTID ||
327 key.type != BTRFS_EXTENT_CSUM_KEY)
328 break;
329
330 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
331 if (key.offset > end)
332 break;
333
334 if (key.offset > start)
335 start = key.offset;
336
337 size = btrfs_item_size_nr(leaf, path->slots[0]);
338 csum_end = key.offset + (size / csum_size) * root->sectorsize;
339 if (csum_end <= start) {
340 path->slots[0]++;
341 continue;
342 }
343
344 csum_end = min(csum_end, end + 1);
345 item = btrfs_item_ptr(path->nodes[0], path->slots[0],
346 struct btrfs_csum_item);
347 while (start < csum_end) {
348 size = min_t(size_t, csum_end - start,
349 MAX_ORDERED_SUM_BYTES(root));
350 sums = kzalloc(btrfs_ordered_sum_size(root, size),
351 GFP_NOFS);
352 BUG_ON(!sums);
353
354 sector_sum = sums->sums;
355 sums->bytenr = start;
356 sums->len = size;
357
358 offset = (start - key.offset) >>
359 root->fs_info->sb->s_blocksize_bits;
360 offset *= csum_size;
361
362 while (size > 0) {
363 read_extent_buffer(path->nodes[0],
364 &sector_sum->sum,
365 ((unsigned long)item) +
366 offset, csum_size);
367 sector_sum->bytenr = start;
368
369 size -= root->sectorsize;
370 start += root->sectorsize;
371 offset += csum_size;
372 sector_sum++;
373 }
374 list_add_tail(&sums->list, list);
375 }
376 path->slots[0]++;
377 }
378 ret = 0;
379 fail:
380 btrfs_free_path(path);
381 return ret;
382 }
383
384 int btrfs_csum_one_bio(struct btrfs_root *root, struct inode *inode,
385 struct bio *bio, u64 file_start, int contig)
386 {
387 struct btrfs_ordered_sum *sums;
388 struct btrfs_sector_sum *sector_sum;
389 struct btrfs_ordered_extent *ordered;
390 char *data;
391 struct bio_vec *bvec = bio->bi_io_vec;
392 int bio_index = 0;
393 unsigned long total_bytes = 0;
394 unsigned long this_sum_bytes = 0;
395 u64 offset;
396 u64 disk_bytenr;
397
398 WARN_ON(bio->bi_vcnt <= 0);
399 sums = kzalloc(btrfs_ordered_sum_size(root, bio->bi_size), GFP_NOFS);
400 if (!sums)
401 return -ENOMEM;
402
403 sector_sum = sums->sums;
404 disk_bytenr = (u64)bio->bi_sector << 9;
405 sums->len = bio->bi_size;
406 INIT_LIST_HEAD(&sums->list);
407
408 if (contig)
409 offset = file_start;
410 else
411 offset = page_offset(bvec->bv_page) + bvec->bv_offset;
412
413 ordered = btrfs_lookup_ordered_extent(inode, offset);
414 BUG_ON(!ordered);
415 sums->bytenr = ordered->start;
416
417 while (bio_index < bio->bi_vcnt) {
418 if (!contig)
419 offset = page_offset(bvec->bv_page) + bvec->bv_offset;
420
421 if (!contig && (offset >= ordered->file_offset + ordered->len ||
422 offset < ordered->file_offset)) {
423 unsigned long bytes_left;
424 sums->len = this_sum_bytes;
425 this_sum_bytes = 0;
426 btrfs_add_ordered_sum(inode, ordered, sums);
427 btrfs_put_ordered_extent(ordered);
428
429 bytes_left = bio->bi_size - total_bytes;
430
431 sums = kzalloc(btrfs_ordered_sum_size(root, bytes_left),
432 GFP_NOFS);
433 BUG_ON(!sums);
434 sector_sum = sums->sums;
435 sums->len = bytes_left;
436 ordered = btrfs_lookup_ordered_extent(inode, offset);
437 BUG_ON(!ordered);
438 sums->bytenr = ordered->start;
439 }
440
441 data = kmap_atomic(bvec->bv_page, KM_USER0);
442 sector_sum->sum = ~(u32)0;
443 sector_sum->sum = btrfs_csum_data(root,
444 data + bvec->bv_offset,
445 sector_sum->sum,
446 bvec->bv_len);
447 kunmap_atomic(data, KM_USER0);
448 btrfs_csum_final(sector_sum->sum,
449 (char *)&sector_sum->sum);
450 sector_sum->bytenr = disk_bytenr;
451
452 sector_sum++;
453 bio_index++;
454 total_bytes += bvec->bv_len;
455 this_sum_bytes += bvec->bv_len;
456 disk_bytenr += bvec->bv_len;
457 offset += bvec->bv_len;
458 bvec++;
459 }
460 this_sum_bytes = 0;
461 btrfs_add_ordered_sum(inode, ordered, sums);
462 btrfs_put_ordered_extent(ordered);
463 return 0;
464 }
465
466 /*
467 * helper function for csum removal, this expects the
468 * key to describe the csum pointed to by the path, and it expects
469 * the csum to overlap the range [bytenr, len]
470 *
471 * The csum should not be entirely contained in the range and the
472 * range should not be entirely contained in the csum.
473 *
474 * This calls btrfs_truncate_item with the correct args based on the
475 * overlap, and fixes up the key as required.
476 */
477 static noinline int truncate_one_csum(struct btrfs_trans_handle *trans,
478 struct btrfs_root *root,
479 struct btrfs_path *path,
480 struct btrfs_key *key,
481 u64 bytenr, u64 len)
482 {
483 struct extent_buffer *leaf;
484 u16 csum_size =
485 btrfs_super_csum_size(&root->fs_info->super_copy);
486 u64 csum_end;
487 u64 end_byte = bytenr + len;
488 u32 blocksize_bits = root->fs_info->sb->s_blocksize_bits;
489 int ret;
490
491 leaf = path->nodes[0];
492 csum_end = btrfs_item_size_nr(leaf, path->slots[0]) / csum_size;
493 csum_end <<= root->fs_info->sb->s_blocksize_bits;
494 csum_end += key->offset;
495
496 if (key->offset < bytenr && csum_end <= end_byte) {
497 /*
498 * [ bytenr - len ]
499 * [ ]
500 * [csum ]
501 * A simple truncate off the end of the item
502 */
503 u32 new_size = (bytenr - key->offset) >> blocksize_bits;
504 new_size *= csum_size;
505 ret = btrfs_truncate_item(trans, root, path, new_size, 1);
506 } else if (key->offset >= bytenr && csum_end > end_byte &&
507 end_byte > key->offset) {
508 /*
509 * [ bytenr - len ]
510 * [ ]
511 * [csum ]
512 * we need to truncate from the beginning of the csum
513 */
514 u32 new_size = (csum_end - end_byte) >> blocksize_bits;
515 new_size *= csum_size;
516
517 ret = btrfs_truncate_item(trans, root, path, new_size, 0);
518
519 key->offset = end_byte;
520 ret = btrfs_set_item_key_safe(trans, root, path, key);
521 BUG_ON(ret);
522 } else {
523 BUG();
524 }
525 return 0;
526 }
527
528 /*
529 * deletes the csum items from the csum tree for a given
530 * range of bytes.
531 */
532 int btrfs_del_csums(struct btrfs_trans_handle *trans,
533 struct btrfs_root *root, u64 bytenr, u64 len)
534 {
535 struct btrfs_path *path;
536 struct btrfs_key key;
537 u64 end_byte = bytenr + len;
538 u64 csum_end;
539 struct extent_buffer *leaf;
540 int ret;
541 u16 csum_size =
542 btrfs_super_csum_size(&root->fs_info->super_copy);
543 int blocksize_bits = root->fs_info->sb->s_blocksize_bits;
544
545 root = root->fs_info->csum_root;
546
547 path = btrfs_alloc_path();
548 if (!path)
549 return -ENOMEM;
550
551 while (1) {
552 key.objectid = BTRFS_EXTENT_CSUM_OBJECTID;
553 key.offset = end_byte - 1;
554 key.type = BTRFS_EXTENT_CSUM_KEY;
555
556 path->leave_spinning = 1;
557 ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
558 if (ret > 0) {
559 if (path->slots[0] == 0)
560 break;
561 path->slots[0]--;
562 } else if (ret < 0) {
563 break;
564 }
565
566 leaf = path->nodes[0];
567 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
568
569 if (key.objectid != BTRFS_EXTENT_CSUM_OBJECTID ||
570 key.type != BTRFS_EXTENT_CSUM_KEY) {
571 break;
572 }
573
574 if (key.offset >= end_byte)
575 break;
576
577 csum_end = btrfs_item_size_nr(leaf, path->slots[0]) / csum_size;
578 csum_end <<= blocksize_bits;
579 csum_end += key.offset;
580
581 /* this csum ends before we start, we're done */
582 if (csum_end <= bytenr)
583 break;
584
585 /* delete the entire item, it is inside our range */
586 if (key.offset >= bytenr && csum_end <= end_byte) {
587 ret = btrfs_del_item(trans, root, path);
588 if (ret)
589 goto out;
590 if (key.offset == bytenr)
591 break;
592 } else if (key.offset < bytenr && csum_end > end_byte) {
593 unsigned long offset;
594 unsigned long shift_len;
595 unsigned long item_offset;
596 /*
597 * [ bytenr - len ]
598 * [csum ]
599 *
600 * Our bytes are in the middle of the csum,
601 * we need to split this item and insert a new one.
602 *
603 * But we can't drop the path because the
604 * csum could change, get removed, extended etc.
605 *
606 * The trick here is the max size of a csum item leaves
607 * enough room in the tree block for a single
608 * item header. So, we split the item in place,
609 * adding a new header pointing to the existing
610 * bytes. Then we loop around again and we have
611 * a nicely formed csum item that we can neatly
612 * truncate.
613 */
614 offset = (bytenr - key.offset) >> blocksize_bits;
615 offset *= csum_size;
616
617 shift_len = (len >> blocksize_bits) * csum_size;
618
619 item_offset = btrfs_item_ptr_offset(leaf,
620 path->slots[0]);
621
622 memset_extent_buffer(leaf, 0, item_offset + offset,
623 shift_len);
624 key.offset = bytenr;
625
626 /*
627 * btrfs_split_item returns -EAGAIN when the
628 * item changed size or key
629 */
630 ret = btrfs_split_item(trans, root, path, &key, offset);
631 BUG_ON(ret && ret != -EAGAIN);
632
633 key.offset = end_byte - 1;
634 } else {
635 ret = truncate_one_csum(trans, root, path,
636 &key, bytenr, len);
637 BUG_ON(ret);
638 if (key.offset < bytenr)
639 break;
640 }
641 btrfs_release_path(path);
642 }
643 ret = 0;
644 out:
645 btrfs_free_path(path);
646 return ret;
647 }
648
649 int btrfs_csum_file_blocks(struct btrfs_trans_handle *trans,
650 struct btrfs_root *root,
651 struct btrfs_ordered_sum *sums)
652 {
653 u64 bytenr;
654 int ret;
655 struct btrfs_key file_key;
656 struct btrfs_key found_key;
657 u64 next_offset;
658 u64 total_bytes = 0;
659 int found_next;
660 struct btrfs_path *path;
661 struct btrfs_csum_item *item;
662 struct btrfs_csum_item *item_end;
663 struct extent_buffer *leaf = NULL;
664 u64 csum_offset;
665 struct btrfs_sector_sum *sector_sum;
666 u32 nritems;
667 u32 ins_size;
668 char *eb_map;
669 char *eb_token;
670 unsigned long map_len;
671 unsigned long map_start;
672 u16 csum_size =
673 btrfs_super_csum_size(&root->fs_info->super_copy);
674
675 path = btrfs_alloc_path();
676 if (!path)
677 return -ENOMEM;
678
679 sector_sum = sums->sums;
680 again:
681 next_offset = (u64)-1;
682 found_next = 0;
683 file_key.objectid = BTRFS_EXTENT_CSUM_OBJECTID;
684 file_key.offset = sector_sum->bytenr;
685 bytenr = sector_sum->bytenr;
686 btrfs_set_key_type(&file_key, BTRFS_EXTENT_CSUM_KEY);
687
688 item = btrfs_lookup_csum(trans, root, path, sector_sum->bytenr, 1);
689 if (!IS_ERR(item)) {
690 leaf = path->nodes[0];
691 ret = 0;
692 goto found;
693 }
694 ret = PTR_ERR(item);
695 if (ret != -EFBIG && ret != -ENOENT)
696 goto fail_unlock;
697
698 if (ret == -EFBIG) {
699 u32 item_size;
700 /* we found one, but it isn't big enough yet */
701 leaf = path->nodes[0];
702 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
703 if ((item_size / csum_size) >=
704 MAX_CSUM_ITEMS(root, csum_size)) {
705 /* already at max size, make a new one */
706 goto insert;
707 }
708 } else {
709 int slot = path->slots[0] + 1;
710 /* we didn't find a csum item, insert one */
711 nritems = btrfs_header_nritems(path->nodes[0]);
712 if (path->slots[0] >= nritems - 1) {
713 ret = btrfs_next_leaf(root, path);
714 if (ret == 1)
715 found_next = 1;
716 if (ret != 0)
717 goto insert;
718 slot = 0;
719 }
720 btrfs_item_key_to_cpu(path->nodes[0], &found_key, slot);
721 if (found_key.objectid != BTRFS_EXTENT_CSUM_OBJECTID ||
722 found_key.type != BTRFS_EXTENT_CSUM_KEY) {
723 found_next = 1;
724 goto insert;
725 }
726 next_offset = found_key.offset;
727 found_next = 1;
728 goto insert;
729 }
730
731 /*
732 * at this point, we know the tree has an item, but it isn't big
733 * enough yet to put our csum in. Grow it
734 */
735 btrfs_release_path(path);
736 ret = btrfs_search_slot(trans, root, &file_key, path,
737 csum_size, 1);
738 if (ret < 0)
739 goto fail_unlock;
740
741 if (ret > 0) {
742 if (path->slots[0] == 0)
743 goto insert;
744 path->slots[0]--;
745 }
746
747 leaf = path->nodes[0];
748 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
749 csum_offset = (bytenr - found_key.offset) >>
750 root->fs_info->sb->s_blocksize_bits;
751
752 if (btrfs_key_type(&found_key) != BTRFS_EXTENT_CSUM_KEY ||
753 found_key.objectid != BTRFS_EXTENT_CSUM_OBJECTID ||
754 csum_offset >= MAX_CSUM_ITEMS(root, csum_size)) {
755 goto insert;
756 }
757
758 if (csum_offset >= btrfs_item_size_nr(leaf, path->slots[0]) /
759 csum_size) {
760 u32 diff = (csum_offset + 1) * csum_size;
761
762 /*
763 * is the item big enough already? we dropped our lock
764 * before and need to recheck
765 */
766 if (diff < btrfs_item_size_nr(leaf, path->slots[0]))
767 goto csum;
768
769 diff = diff - btrfs_item_size_nr(leaf, path->slots[0]);
770 if (diff != csum_size)
771 goto insert;
772
773 ret = btrfs_extend_item(trans, root, path, diff);
774 goto csum;
775 }
776
777 insert:
778 btrfs_release_path(path);
779 csum_offset = 0;
780 if (found_next) {
781 u64 tmp = total_bytes + root->sectorsize;
782 u64 next_sector = sector_sum->bytenr;
783 struct btrfs_sector_sum *next = sector_sum + 1;
784
785 while (tmp < sums->len) {
786 if (next_sector + root->sectorsize != next->bytenr)
787 break;
788 tmp += root->sectorsize;
789 next_sector = next->bytenr;
790 next++;
791 }
792 tmp = min(tmp, next_offset - file_key.offset);
793 tmp >>= root->fs_info->sb->s_blocksize_bits;
794 tmp = max((u64)1, tmp);
795 tmp = min(tmp, (u64)MAX_CSUM_ITEMS(root, csum_size));
796 ins_size = csum_size * tmp;
797 } else {
798 ins_size = csum_size;
799 }
800 path->leave_spinning = 1;
801 ret = btrfs_insert_empty_item(trans, root, path, &file_key,
802 ins_size);
803 path->leave_spinning = 0;
804 if (ret < 0)
805 goto fail_unlock;
806 if (ret != 0) {
807 WARN_ON(1);
808 goto fail_unlock;
809 }
810 csum:
811 leaf = path->nodes[0];
812 item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_csum_item);
813 ret = 0;
814 item = (struct btrfs_csum_item *)((unsigned char *)item +
815 csum_offset * csum_size);
816 found:
817 item_end = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_csum_item);
818 item_end = (struct btrfs_csum_item *)((unsigned char *)item_end +
819 btrfs_item_size_nr(leaf, path->slots[0]));
820 eb_token = NULL;
821 next_sector:
822
823 if (!eb_token ||
824 (unsigned long)item + csum_size >= map_start + map_len) {
825 int err;
826
827 if (eb_token)
828 unmap_extent_buffer(leaf, eb_token, KM_USER1);
829 eb_token = NULL;
830 err = map_private_extent_buffer(leaf, (unsigned long)item,
831 csum_size,
832 &eb_token, &eb_map,
833 &map_start, &map_len, KM_USER1);
834 if (err)
835 eb_token = NULL;
836 }
837 if (eb_token) {
838 memcpy(eb_token + ((unsigned long)item & (PAGE_CACHE_SIZE - 1)),
839 &sector_sum->sum, csum_size);
840 } else {
841 write_extent_buffer(leaf, &sector_sum->sum,
842 (unsigned long)item, csum_size);
843 }
844
845 total_bytes += root->sectorsize;
846 sector_sum++;
847 if (total_bytes < sums->len) {
848 item = (struct btrfs_csum_item *)((char *)item +
849 csum_size);
850 if (item < item_end && bytenr + PAGE_CACHE_SIZE ==
851 sector_sum->bytenr) {
852 bytenr = sector_sum->bytenr;
853 goto next_sector;
854 }
855 }
856 if (eb_token) {
857 unmap_extent_buffer(leaf, eb_token, KM_USER1);
858 eb_token = NULL;
859 }
860 btrfs_mark_buffer_dirty(path->nodes[0]);
861 if (total_bytes < sums->len) {
862 btrfs_release_path(path);
863 cond_resched();
864 goto again;
865 }
866 out:
867 btrfs_free_path(path);
868 return ret;
869
870 fail_unlock:
871 goto out;
872 }
Linux kernel - Deliverables
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