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) ((unsigned long)(((BTRFS_LEAF_DATA_SIZE(r) - \
29 sizeof(struct btrfs_item) * 2) / \
30 size) - 1))
31
32 #define MAX_CSUM_ITEMS(r, size) (min_t(u32, __MAX_CSUM_ITEMS(r, size), \
33 PAGE_CACHE_SIZE))
34
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)
39
btrfs_insert_file_extent(struct btrfs_trans_handle * trans,struct btrfs_root * root,u64 objectid,u64 pos,u64 disk_offset,u64 disk_num_bytes,u64 num_bytes,u64 offset,u64 ram_bytes,u8 compression,u8 encryption,u16 other_encoding)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)
46 {
47 int ret = 0;
48 struct btrfs_file_extent_item *item;
49 struct btrfs_key file_key;
50 struct btrfs_path *path;
51 struct extent_buffer *leaf;
52
53 path = btrfs_alloc_path();
54 if (!path)
55 return -ENOMEM;
56 file_key.objectid = objectid;
57 file_key.offset = pos;
58 btrfs_set_key_type(&file_key, BTRFS_EXTENT_DATA_KEY);
59
60 path->leave_spinning = 1;
61 ret = btrfs_insert_empty_item(trans, root, path, &file_key,
62 sizeof(*item));
63 if (ret < 0)
64 goto out;
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);
79
80 btrfs_mark_buffer_dirty(leaf);
81 out:
82 btrfs_free_path(path);
83 return ret;
84 }
85
86 static struct btrfs_csum_item *
btrfs_lookup_csum(struct btrfs_trans_handle * trans,struct btrfs_root * root,struct btrfs_path * path,u64 bytenr,int cow)87 btrfs_lookup_csum(struct btrfs_trans_handle *trans,
88 struct btrfs_root *root,
89 struct btrfs_path *path,
90 u64 bytenr, int cow)
91 {
92 int ret;
93 struct btrfs_key file_key;
94 struct btrfs_key found_key;
95 struct btrfs_csum_item *item;
96 struct extent_buffer *leaf;
97 u64 csum_offset = 0;
98 u16 csum_size = btrfs_super_csum_size(root->fs_info->super_copy);
99 int csums_in_item;
100
101 file_key.objectid = BTRFS_EXTENT_CSUM_OBJECTID;
102 file_key.offset = bytenr;
103 btrfs_set_key_type(&file_key, BTRFS_EXTENT_CSUM_KEY);
104 ret = btrfs_search_slot(trans, root, &file_key, path, 0, cow);
105 if (ret < 0)
106 goto fail;
107 leaf = path->nodes[0];
108 if (ret > 0) {
109 ret = 1;
110 if (path->slots[0] == 0)
111 goto fail;
112 path->slots[0]--;
113 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
114 if (btrfs_key_type(&found_key) != BTRFS_EXTENT_CSUM_KEY)
115 goto fail;
116
117 csum_offset = (bytenr - found_key.offset) >>
118 root->fs_info->sb->s_blocksize_bits;
119 csums_in_item = btrfs_item_size_nr(leaf, path->slots[0]);
120 csums_in_item /= csum_size;
121
122 if (csum_offset == csums_in_item) {
123 ret = -EFBIG;
124 goto fail;
125 } else if (csum_offset > csums_in_item) {
126 goto fail;
127 }
128 }
129 item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_csum_item);
130 item = (struct btrfs_csum_item *)((unsigned char *)item +
131 csum_offset * csum_size);
132 return item;
133 fail:
134 if (ret > 0)
135 ret = -ENOENT;
136 return ERR_PTR(ret);
137 }
138
btrfs_lookup_file_extent(struct btrfs_trans_handle * trans,struct btrfs_root * root,struct btrfs_path * path,u64 objectid,u64 offset,int mod)139 int btrfs_lookup_file_extent(struct btrfs_trans_handle *trans,
140 struct btrfs_root *root,
141 struct btrfs_path *path, u64 objectid,
142 u64 offset, int mod)
143 {
144 int ret;
145 struct btrfs_key file_key;
146 int ins_len = mod < 0 ? -1 : 0;
147 int cow = mod != 0;
148
149 file_key.objectid = objectid;
150 file_key.offset = offset;
151 btrfs_set_key_type(&file_key, BTRFS_EXTENT_DATA_KEY);
152 ret = btrfs_search_slot(trans, root, &file_key, path, ins_len, cow);
153 return ret;
154 }
155
__btrfs_lookup_bio_sums(struct btrfs_root * root,struct inode * inode,struct bio * bio,u64 logical_offset,u32 * dst,int dio)156 static int __btrfs_lookup_bio_sums(struct btrfs_root *root,
157 struct inode *inode, struct bio *bio,
158 u64 logical_offset, u32 *dst, int dio)
159 {
160 u32 sum[16];
161 int len;
162 struct bio_vec *bvec = bio->bi_io_vec;
163 int bio_index = 0;
164 u64 offset = 0;
165 u64 item_start_offset = 0;
166 u64 item_last_offset = 0;
167 u64 disk_bytenr;
168 u32 diff;
169 u16 csum_size = btrfs_super_csum_size(root->fs_info->super_copy);
170 int count;
171 struct btrfs_path *path;
172 struct btrfs_csum_item *item = NULL;
173 struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
174
175 path = btrfs_alloc_path();
176 if (!path)
177 return -ENOMEM;
178 if (bio->bi_size > PAGE_CACHE_SIZE * 8)
179 path->reada = 2;
180
181 WARN_ON(bio->bi_vcnt <= 0);
182
183 /*
184 * the free space stuff is only read when it hasn't been
185 * updated in the current transaction. So, we can safely
186 * read from the commit root and sidestep a nasty deadlock
187 * between reading the free space cache and updating the csum tree.
188 */
189 if (btrfs_is_free_space_inode(inode)) {
190 path->search_commit_root = 1;
191 path->skip_locking = 1;
192 }
193
194 disk_bytenr = (u64)bio->bi_sector << 9;
195 if (dio)
196 offset = logical_offset;
197 while (bio_index < bio->bi_vcnt) {
198 len = min_t(int, ARRAY_SIZE(sum), bio->bi_vcnt - bio_index);
199 if (!dio)
200 offset = page_offset(bvec->bv_page) + bvec->bv_offset;
201 count = btrfs_find_ordered_sum(inode, offset, disk_bytenr, sum,
202 len);
203 if (count)
204 goto found;
205
206 if (!item || disk_bytenr < item_start_offset ||
207 disk_bytenr >= item_last_offset) {
208 struct btrfs_key found_key;
209 u32 item_size;
210
211 if (item)
212 btrfs_release_path(path);
213 item = btrfs_lookup_csum(NULL, root->fs_info->csum_root,
214 path, disk_bytenr, 0);
215 if (IS_ERR(item)) {
216 count = 1;
217 sum[0] = 0;
218 if (BTRFS_I(inode)->root->root_key.objectid ==
219 BTRFS_DATA_RELOC_TREE_OBJECTID) {
220 set_extent_bits(io_tree, offset,
221 offset + bvec->bv_len - 1,
222 EXTENT_NODATASUM, GFP_NOFS);
223 } else {
224 printk(KERN_INFO "btrfs no csum found "
225 "for inode %llu start %llu\n",
226 (unsigned long long)
227 btrfs_ino(inode),
228 (unsigned long long)offset);
229 }
230 item = NULL;
231 btrfs_release_path(path);
232 goto found;
233 }
234 btrfs_item_key_to_cpu(path->nodes[0], &found_key,
235 path->slots[0]);
236
237 item_start_offset = found_key.offset;
238 item_size = btrfs_item_size_nr(path->nodes[0],
239 path->slots[0]);
240 item_last_offset = item_start_offset +
241 (item_size / csum_size) *
242 root->sectorsize;
243 item = btrfs_item_ptr(path->nodes[0], path->slots[0],
244 struct btrfs_csum_item);
245 }
246 /*
247 * this byte range must be able to fit inside
248 * a single leaf so it will also fit inside a u32
249 */
250 diff = disk_bytenr - item_start_offset;
251 diff = diff / root->sectorsize;
252 diff = diff * csum_size;
253 count = min_t(int, len, (item_last_offset - disk_bytenr) >>
254 inode->i_sb->s_blocksize_bits);
255 read_extent_buffer(path->nodes[0], sum,
256 ((unsigned long)item) + diff,
257 csum_size * count);
258 found:
259 if (dst) {
260 memcpy(dst, sum, count * csum_size);
261 dst += count;
262 } else {
263 if (dio)
264 extent_cache_csums_dio(io_tree, offset, sum,
265 count);
266 else
267 extent_cache_csums(io_tree, bio, bio_index, sum,
268 count);
269 }
270 while (count--) {
271 disk_bytenr += bvec->bv_len;
272 offset += bvec->bv_len;
273 bio_index++;
274 bvec++;
275 }
276 }
277 btrfs_free_path(path);
278 return 0;
279 }
280
btrfs_lookup_bio_sums(struct btrfs_root * root,struct inode * inode,struct bio * bio,u32 * dst)281 int btrfs_lookup_bio_sums(struct btrfs_root *root, struct inode *inode,
282 struct bio *bio, u32 *dst)
283 {
284 return __btrfs_lookup_bio_sums(root, inode, bio, 0, dst, 0);
285 }
286
btrfs_lookup_bio_sums_dio(struct btrfs_root * root,struct inode * inode,struct bio * bio,u64 offset)287 int btrfs_lookup_bio_sums_dio(struct btrfs_root *root, struct inode *inode,
288 struct bio *bio, u64 offset)
289 {
290 return __btrfs_lookup_bio_sums(root, inode, bio, offset, NULL, 1);
291 }
292
btrfs_lookup_csums_range(struct btrfs_root * root,u64 start,u64 end,struct list_head * list,int search_commit)293 int btrfs_lookup_csums_range(struct btrfs_root *root, u64 start, u64 end,
294 struct list_head *list, int search_commit)
295 {
296 struct btrfs_key key;
297 struct btrfs_path *path;
298 struct extent_buffer *leaf;
299 struct btrfs_ordered_sum *sums;
300 struct btrfs_sector_sum *sector_sum;
301 struct btrfs_csum_item *item;
302 LIST_HEAD(tmplist);
303 unsigned long offset;
304 int ret;
305 size_t size;
306 u64 csum_end;
307 u16 csum_size = btrfs_super_csum_size(root->fs_info->super_copy);
308
309 path = btrfs_alloc_path();
310 if (!path)
311 return -ENOMEM;
312
313 if (search_commit) {
314 path->skip_locking = 1;
315 path->reada = 2;
316 path->search_commit_root = 1;
317 }
318
319 key.objectid = BTRFS_EXTENT_CSUM_OBJECTID;
320 key.offset = start;
321 key.type = BTRFS_EXTENT_CSUM_KEY;
322
323 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
324 if (ret < 0)
325 goto fail;
326 if (ret > 0 && path->slots[0] > 0) {
327 leaf = path->nodes[0];
328 btrfs_item_key_to_cpu(leaf, &key, path->slots[0] - 1);
329 if (key.objectid == BTRFS_EXTENT_CSUM_OBJECTID &&
330 key.type == BTRFS_EXTENT_CSUM_KEY) {
331 offset = (start - key.offset) >>
332 root->fs_info->sb->s_blocksize_bits;
333 if (offset * csum_size <
334 btrfs_item_size_nr(leaf, path->slots[0] - 1))
335 path->slots[0]--;
336 }
337 }
338
339 while (start <= end) {
340 leaf = path->nodes[0];
341 if (path->slots[0] >= btrfs_header_nritems(leaf)) {
342 ret = btrfs_next_leaf(root, path);
343 if (ret < 0)
344 goto fail;
345 if (ret > 0)
346 break;
347 leaf = path->nodes[0];
348 }
349
350 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
351 if (key.objectid != BTRFS_EXTENT_CSUM_OBJECTID ||
352 key.type != BTRFS_EXTENT_CSUM_KEY ||
353 key.offset > end)
354 break;
355
356 if (key.offset > start)
357 start = key.offset;
358
359 size = btrfs_item_size_nr(leaf, path->slots[0]);
360 csum_end = key.offset + (size / csum_size) * root->sectorsize;
361 if (csum_end <= start) {
362 path->slots[0]++;
363 continue;
364 }
365
366 csum_end = min(csum_end, end + 1);
367 item = btrfs_item_ptr(path->nodes[0], path->slots[0],
368 struct btrfs_csum_item);
369 while (start < csum_end) {
370 size = min_t(size_t, csum_end - start,
371 MAX_ORDERED_SUM_BYTES(root));
372 sums = kzalloc(btrfs_ordered_sum_size(root, size),
373 GFP_NOFS);
374 if (!sums) {
375 ret = -ENOMEM;
376 goto fail;
377 }
378
379 sector_sum = sums->sums;
380 sums->bytenr = start;
381 sums->len = size;
382
383 offset = (start - key.offset) >>
384 root->fs_info->sb->s_blocksize_bits;
385 offset *= csum_size;
386
387 while (size > 0) {
388 read_extent_buffer(path->nodes[0],
389 §or_sum->sum,
390 ((unsigned long)item) +
391 offset, csum_size);
392 sector_sum->bytenr = start;
393
394 size -= root->sectorsize;
395 start += root->sectorsize;
396 offset += csum_size;
397 sector_sum++;
398 }
399 list_add_tail(&sums->list, &tmplist);
400 }
401 path->slots[0]++;
402 }
403 ret = 0;
404 fail:
405 while (ret < 0 && !list_empty(&tmplist)) {
406 sums = list_entry(&tmplist, struct btrfs_ordered_sum, list);
407 list_del(&sums->list);
408 kfree(sums);
409 }
410 list_splice_tail(&tmplist, list);
411
412 btrfs_free_path(path);
413 return ret;
414 }
415
btrfs_csum_one_bio(struct btrfs_root * root,struct inode * inode,struct bio * bio,u64 file_start,int contig)416 int btrfs_csum_one_bio(struct btrfs_root *root, struct inode *inode,
417 struct bio *bio, u64 file_start, int contig)
418 {
419 struct btrfs_ordered_sum *sums;
420 struct btrfs_sector_sum *sector_sum;
421 struct btrfs_ordered_extent *ordered;
422 char *data;
423 struct bio_vec *bvec = bio->bi_io_vec;
424 int bio_index = 0;
425 unsigned long total_bytes = 0;
426 unsigned long this_sum_bytes = 0;
427 u64 offset;
428 u64 disk_bytenr;
429
430 WARN_ON(bio->bi_vcnt <= 0);
431 sums = kzalloc(btrfs_ordered_sum_size(root, bio->bi_size), GFP_NOFS);
432 if (!sums)
433 return -ENOMEM;
434
435 sector_sum = sums->sums;
436 disk_bytenr = (u64)bio->bi_sector << 9;
437 sums->len = bio->bi_size;
438 INIT_LIST_HEAD(&sums->list);
439
440 if (contig)
441 offset = file_start;
442 else
443 offset = page_offset(bvec->bv_page) + bvec->bv_offset;
444
445 ordered = btrfs_lookup_ordered_extent(inode, offset);
446 BUG_ON(!ordered); /* Logic error */
447 sums->bytenr = ordered->start;
448
449 while (bio_index < bio->bi_vcnt) {
450 if (!contig)
451 offset = page_offset(bvec->bv_page) + bvec->bv_offset;
452
453 if (offset >= ordered->file_offset + ordered->len ||
454 offset < ordered->file_offset) {
455 unsigned long bytes_left;
456 sums->len = this_sum_bytes;
457 this_sum_bytes = 0;
458 btrfs_add_ordered_sum(inode, ordered, sums);
459 btrfs_put_ordered_extent(ordered);
460
461 bytes_left = bio->bi_size - total_bytes;
462
463 sums = kzalloc(btrfs_ordered_sum_size(root, bytes_left),
464 GFP_NOFS);
465 BUG_ON(!sums); /* -ENOMEM */
466 sector_sum = sums->sums;
467 sums->len = bytes_left;
468 ordered = btrfs_lookup_ordered_extent(inode, offset);
469 BUG_ON(!ordered); /* Logic error */
470 sums->bytenr = ordered->start;
471 }
472
473 data = kmap_atomic(bvec->bv_page);
474 sector_sum->sum = ~(u32)0;
475 sector_sum->sum = btrfs_csum_data(data + bvec->bv_offset,
476 sector_sum->sum,
477 bvec->bv_len);
478 kunmap_atomic(data);
479 btrfs_csum_final(sector_sum->sum,
480 (char *)§or_sum->sum);
481 sector_sum->bytenr = disk_bytenr;
482
483 sector_sum++;
484 bio_index++;
485 total_bytes += bvec->bv_len;
486 this_sum_bytes += bvec->bv_len;
487 disk_bytenr += bvec->bv_len;
488 offset += bvec->bv_len;
489 bvec++;
490 }
491 this_sum_bytes = 0;
492 btrfs_add_ordered_sum(inode, ordered, sums);
493 btrfs_put_ordered_extent(ordered);
494 return 0;
495 }
496
497 /*
498 * helper function for csum removal, this expects the
499 * key to describe the csum pointed to by the path, and it expects
500 * the csum to overlap the range [bytenr, len]
501 *
502 * The csum should not be entirely contained in the range and the
503 * range should not be entirely contained in the csum.
504 *
505 * This calls btrfs_truncate_item with the correct args based on the
506 * overlap, and fixes up the key as required.
507 */
truncate_one_csum(struct btrfs_root * root,struct btrfs_path * path,struct btrfs_key * key,u64 bytenr,u64 len)508 static noinline void truncate_one_csum(struct btrfs_root *root,
509 struct btrfs_path *path,
510 struct btrfs_key *key,
511 u64 bytenr, u64 len)
512 {
513 struct extent_buffer *leaf;
514 u16 csum_size = btrfs_super_csum_size(root->fs_info->super_copy);
515 u64 csum_end;
516 u64 end_byte = bytenr + len;
517 u32 blocksize_bits = root->fs_info->sb->s_blocksize_bits;
518
519 leaf = path->nodes[0];
520 csum_end = btrfs_item_size_nr(leaf, path->slots[0]) / csum_size;
521 csum_end <<= root->fs_info->sb->s_blocksize_bits;
522 csum_end += key->offset;
523
524 if (key->offset < bytenr && csum_end <= end_byte) {
525 /*
526 * [ bytenr - len ]
527 * [ ]
528 * [csum ]
529 * A simple truncate off the end of the item
530 */
531 u32 new_size = (bytenr - key->offset) >> blocksize_bits;
532 new_size *= csum_size;
533 btrfs_truncate_item(root, path, new_size, 1);
534 } else if (key->offset >= bytenr && csum_end > end_byte &&
535 end_byte > key->offset) {
536 /*
537 * [ bytenr - len ]
538 * [ ]
539 * [csum ]
540 * we need to truncate from the beginning of the csum
541 */
542 u32 new_size = (csum_end - end_byte) >> blocksize_bits;
543 new_size *= csum_size;
544
545 btrfs_truncate_item(root, path, new_size, 0);
546
547 key->offset = end_byte;
548 btrfs_set_item_key_safe(root, path, key);
549 } else {
550 BUG();
551 }
552 }
553
554 /*
555 * deletes the csum items from the csum tree for a given
556 * range of bytes.
557 */
btrfs_del_csums(struct btrfs_trans_handle * trans,struct btrfs_root * root,u64 bytenr,u64 len)558 int btrfs_del_csums(struct btrfs_trans_handle *trans,
559 struct btrfs_root *root, u64 bytenr, u64 len)
560 {
561 struct btrfs_path *path;
562 struct btrfs_key key;
563 u64 end_byte = bytenr + len;
564 u64 csum_end;
565 struct extent_buffer *leaf;
566 int ret;
567 u16 csum_size = btrfs_super_csum_size(root->fs_info->super_copy);
568 int blocksize_bits = root->fs_info->sb->s_blocksize_bits;
569
570 root = root->fs_info->csum_root;
571
572 path = btrfs_alloc_path();
573 if (!path)
574 return -ENOMEM;
575
576 while (1) {
577 key.objectid = BTRFS_EXTENT_CSUM_OBJECTID;
578 key.offset = end_byte - 1;
579 key.type = BTRFS_EXTENT_CSUM_KEY;
580
581 path->leave_spinning = 1;
582 ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
583 if (ret > 0) {
584 if (path->slots[0] == 0)
585 break;
586 path->slots[0]--;
587 } else if (ret < 0) {
588 break;
589 }
590
591 leaf = path->nodes[0];
592 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
593
594 if (key.objectid != BTRFS_EXTENT_CSUM_OBJECTID ||
595 key.type != BTRFS_EXTENT_CSUM_KEY) {
596 break;
597 }
598
599 if (key.offset >= end_byte)
600 break;
601
602 csum_end = btrfs_item_size_nr(leaf, path->slots[0]) / csum_size;
603 csum_end <<= blocksize_bits;
604 csum_end += key.offset;
605
606 /* this csum ends before we start, we're done */
607 if (csum_end <= bytenr)
608 break;
609
610 /* delete the entire item, it is inside our range */
611 if (key.offset >= bytenr && csum_end <= end_byte) {
612 ret = btrfs_del_item(trans, root, path);
613 if (ret)
614 goto out;
615 if (key.offset == bytenr)
616 break;
617 } else if (key.offset < bytenr && csum_end > end_byte) {
618 unsigned long offset;
619 unsigned long shift_len;
620 unsigned long item_offset;
621 /*
622 * [ bytenr - len ]
623 * [csum ]
624 *
625 * Our bytes are in the middle of the csum,
626 * we need to split this item and insert a new one.
627 *
628 * But we can't drop the path because the
629 * csum could change, get removed, extended etc.
630 *
631 * The trick here is the max size of a csum item leaves
632 * enough room in the tree block for a single
633 * item header. So, we split the item in place,
634 * adding a new header pointing to the existing
635 * bytes. Then we loop around again and we have
636 * a nicely formed csum item that we can neatly
637 * truncate.
638 */
639 offset = (bytenr - key.offset) >> blocksize_bits;
640 offset *= csum_size;
641
642 shift_len = (len >> blocksize_bits) * csum_size;
643
644 item_offset = btrfs_item_ptr_offset(leaf,
645 path->slots[0]);
646
647 memset_extent_buffer(leaf, 0, item_offset + offset,
648 shift_len);
649 key.offset = bytenr;
650
651 /*
652 * btrfs_split_item returns -EAGAIN when the
653 * item changed size or key
654 */
655 ret = btrfs_split_item(trans, root, path, &key, offset);
656 if (ret && ret != -EAGAIN) {
657 btrfs_abort_transaction(trans, root, ret);
658 goto out;
659 }
660
661 key.offset = end_byte - 1;
662 } else {
663 truncate_one_csum(root, path, &key, bytenr, len);
664 if (key.offset < bytenr)
665 break;
666 }
667 btrfs_release_path(path);
668 }
669 ret = 0;
670 out:
671 btrfs_free_path(path);
672 return ret;
673 }
674
btrfs_sector_sum_left(struct btrfs_ordered_sum * sums,struct btrfs_sector_sum * sector_sum,u64 total_bytes,u64 sectorsize)675 static u64 btrfs_sector_sum_left(struct btrfs_ordered_sum *sums,
676 struct btrfs_sector_sum *sector_sum,
677 u64 total_bytes, u64 sectorsize)
678 {
679 u64 tmp = sectorsize;
680 u64 next_sector = sector_sum->bytenr;
681 struct btrfs_sector_sum *next = sector_sum + 1;
682
683 while ((tmp + total_bytes) < sums->len) {
684 if (next_sector + sectorsize != next->bytenr)
685 break;
686 tmp += sectorsize;
687 next_sector = next->bytenr;
688 next++;
689 }
690 return tmp;
691 }
692
btrfs_csum_file_blocks(struct btrfs_trans_handle * trans,struct btrfs_root * root,struct btrfs_ordered_sum * sums)693 int btrfs_csum_file_blocks(struct btrfs_trans_handle *trans,
694 struct btrfs_root *root,
695 struct btrfs_ordered_sum *sums)
696 {
697 u64 bytenr;
698 int ret;
699 struct btrfs_key file_key;
700 struct btrfs_key found_key;
701 u64 next_offset;
702 u64 total_bytes = 0;
703 int found_next;
704 struct btrfs_path *path;
705 struct btrfs_csum_item *item;
706 struct btrfs_csum_item *item_end;
707 struct extent_buffer *leaf = NULL;
708 u64 csum_offset;
709 struct btrfs_sector_sum *sector_sum;
710 u32 nritems;
711 u32 ins_size;
712 u16 csum_size = btrfs_super_csum_size(root->fs_info->super_copy);
713
714 path = btrfs_alloc_path();
715 if (!path)
716 return -ENOMEM;
717
718 sector_sum = sums->sums;
719 again:
720 next_offset = (u64)-1;
721 found_next = 0;
722 file_key.objectid = BTRFS_EXTENT_CSUM_OBJECTID;
723 file_key.offset = sector_sum->bytenr;
724 bytenr = sector_sum->bytenr;
725 btrfs_set_key_type(&file_key, BTRFS_EXTENT_CSUM_KEY);
726
727 item = btrfs_lookup_csum(trans, root, path, sector_sum->bytenr, 1);
728 if (!IS_ERR(item)) {
729 leaf = path->nodes[0];
730 ret = 0;
731 goto found;
732 }
733 ret = PTR_ERR(item);
734 if (ret != -EFBIG && ret != -ENOENT)
735 goto fail_unlock;
736
737 if (ret == -EFBIG) {
738 u32 item_size;
739 /* we found one, but it isn't big enough yet */
740 leaf = path->nodes[0];
741 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
742 if ((item_size / csum_size) >=
743 MAX_CSUM_ITEMS(root, csum_size)) {
744 /* already at max size, make a new one */
745 goto insert;
746 }
747 } else {
748 int slot = path->slots[0] + 1;
749 /* we didn't find a csum item, insert one */
750 nritems = btrfs_header_nritems(path->nodes[0]);
751 if (path->slots[0] >= nritems - 1) {
752 ret = btrfs_next_leaf(root, path);
753 if (ret == 1)
754 found_next = 1;
755 if (ret != 0)
756 goto insert;
757 slot = 0;
758 }
759 btrfs_item_key_to_cpu(path->nodes[0], &found_key, slot);
760 if (found_key.objectid != BTRFS_EXTENT_CSUM_OBJECTID ||
761 found_key.type != BTRFS_EXTENT_CSUM_KEY) {
762 found_next = 1;
763 goto insert;
764 }
765 next_offset = found_key.offset;
766 found_next = 1;
767 goto insert;
768 }
769
770 /*
771 * at this point, we know the tree has an item, but it isn't big
772 * enough yet to put our csum in. Grow it
773 */
774 btrfs_release_path(path);
775 ret = btrfs_search_slot(trans, root, &file_key, path,
776 csum_size, 1);
777 if (ret < 0)
778 goto fail_unlock;
779
780 if (ret > 0) {
781 if (path->slots[0] == 0)
782 goto insert;
783 path->slots[0]--;
784 }
785
786 leaf = path->nodes[0];
787 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
788 csum_offset = (bytenr - found_key.offset) >>
789 root->fs_info->sb->s_blocksize_bits;
790
791 if (btrfs_key_type(&found_key) != BTRFS_EXTENT_CSUM_KEY ||
792 found_key.objectid != BTRFS_EXTENT_CSUM_OBJECTID ||
793 csum_offset >= MAX_CSUM_ITEMS(root, csum_size)) {
794 goto insert;
795 }
796
797 if (csum_offset == btrfs_item_size_nr(leaf, path->slots[0]) /
798 csum_size) {
799 int extend_nr;
800 u64 tmp;
801 u32 diff;
802 u32 free_space;
803
804 if (btrfs_leaf_free_space(root, leaf) <
805 sizeof(struct btrfs_item) + csum_size * 2)
806 goto insert;
807
808 free_space = btrfs_leaf_free_space(root, leaf) -
809 sizeof(struct btrfs_item) - csum_size;
810 tmp = btrfs_sector_sum_left(sums, sector_sum, total_bytes,
811 root->sectorsize);
812 tmp >>= root->fs_info->sb->s_blocksize_bits;
813 WARN_ON(tmp < 1);
814
815 extend_nr = max_t(int, 1, (int)tmp);
816 diff = (csum_offset + extend_nr) * csum_size;
817 diff = min(diff, MAX_CSUM_ITEMS(root, csum_size) * csum_size);
818
819 diff = diff - btrfs_item_size_nr(leaf, path->slots[0]);
820 diff = min(free_space, diff);
821 diff /= csum_size;
822 diff *= csum_size;
823
824 btrfs_extend_item(root, path, diff);
825 goto csum;
826 }
827
828 insert:
829 btrfs_release_path(path);
830 csum_offset = 0;
831 if (found_next) {
832 u64 tmp;
833
834 tmp = btrfs_sector_sum_left(sums, sector_sum, total_bytes,
835 root->sectorsize);
836 tmp >>= root->fs_info->sb->s_blocksize_bits;
837 tmp = min(tmp, (next_offset - file_key.offset) >>
838 root->fs_info->sb->s_blocksize_bits);
839
840 tmp = max((u64)1, tmp);
841 tmp = min(tmp, (u64)MAX_CSUM_ITEMS(root, csum_size));
842 ins_size = csum_size * tmp;
843 } else {
844 ins_size = csum_size;
845 }
846 path->leave_spinning = 1;
847 ret = btrfs_insert_empty_item(trans, root, path, &file_key,
848 ins_size);
849 path->leave_spinning = 0;
850 if (ret < 0)
851 goto fail_unlock;
852 if (ret != 0) {
853 WARN_ON(1);
854 goto fail_unlock;
855 }
856 csum:
857 leaf = path->nodes[0];
858 item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_csum_item);
859 ret = 0;
860 item = (struct btrfs_csum_item *)((unsigned char *)item +
861 csum_offset * csum_size);
862 found:
863 item_end = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_csum_item);
864 item_end = (struct btrfs_csum_item *)((unsigned char *)item_end +
865 btrfs_item_size_nr(leaf, path->slots[0]));
866 next_sector:
867
868 write_extent_buffer(leaf, §or_sum->sum, (unsigned long)item, csum_size);
869
870 total_bytes += root->sectorsize;
871 sector_sum++;
872 if (total_bytes < sums->len) {
873 item = (struct btrfs_csum_item *)((char *)item +
874 csum_size);
875 if (item < item_end && bytenr + PAGE_CACHE_SIZE ==
876 sector_sum->bytenr) {
877 bytenr = sector_sum->bytenr;
878 goto next_sector;
879 }
880 }
881
882 btrfs_mark_buffer_dirty(path->nodes[0]);
883 if (total_bytes < sums->len) {
884 btrfs_release_path(path);
885 cond_resched();
886 goto again;
887 }
888 out:
889 btrfs_free_path(path);
890 return ret;
891
892 fail_unlock:
893 goto out;
894 }
895