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RT-AC56 3.0.0.4.374.37 core
[tomato.git] / release / src-rt-6.x.4708 / linux / linux-2.6.36 / fs / btrfs / file-item.c
bloba562a250ae773f9c6607ac2034b8ed84bf28e784
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 BUG_ON(!path);
52 file_key.objectid = objectid;
53 file_key.offset = pos;
54 btrfs_set_key_type(&file_key, BTRFS_EXTENT_DATA_KEY);
55
56 path->leave_spinning = 1;
57 ret = btrfs_insert_empty_item(trans, root, path, &file_key,
58 sizeof(*item));
59 if (ret < 0)
60 goto out;
61 BUG_ON(ret);
62 leaf = path->nodes[0];
63 item = btrfs_item_ptr(leaf, path->slots[0],
64 struct btrfs_file_extent_item);
65 btrfs_set_file_extent_disk_bytenr(leaf, item, disk_offset);
66 btrfs_set_file_extent_disk_num_bytes(leaf, item, disk_num_bytes);
67 btrfs_set_file_extent_offset(leaf, item, offset);
68 btrfs_set_file_extent_num_bytes(leaf, item, num_bytes);
69 btrfs_set_file_extent_ram_bytes(leaf, item, ram_bytes);
70 btrfs_set_file_extent_generation(leaf, item, trans->transid);
71 btrfs_set_file_extent_type(leaf, item, BTRFS_FILE_EXTENT_REG);
72 btrfs_set_file_extent_compression(leaf, item, compression);
73 btrfs_set_file_extent_encryption(leaf, item, encryption);
74 btrfs_set_file_extent_other_encoding(leaf, item, other_encoding);
75
76 btrfs_mark_buffer_dirty(leaf);
77 out:
78 btrfs_free_path(path);
79 return ret;
80 }
81
82 struct btrfs_csum_item *btrfs_lookup_csum(struct btrfs_trans_handle *trans,
83 struct btrfs_root *root,
84 struct btrfs_path *path,
85 u64 bytenr, int cow)
86 {
87 int ret;
88 struct btrfs_key file_key;
89 struct btrfs_key found_key;
90 struct btrfs_csum_item *item;
91 struct extent_buffer *leaf;
92 u64 csum_offset = 0;
93 u16 csum_size =
94 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 =
165 btrfs_super_csum_size(&root->fs_info->super_copy);
166 int ret;
167 struct btrfs_path *path;
168 struct btrfs_csum_item *item = NULL;
169 struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
170
171 path = btrfs_alloc_path();
172 if (bio->bi_size > PAGE_CACHE_SIZE * 8)
173 path->reada = 2;
174
175 WARN_ON(bio->bi_vcnt <= 0);
176
177 disk_bytenr = (u64)bio->bi_sector << 9;
178 if (dio)
179 offset = logical_offset;
180 while (bio_index < bio->bi_vcnt) {
181 if (!dio)
182 offset = page_offset(bvec->bv_page) + bvec->bv_offset;
183 ret = btrfs_find_ordered_sum(inode, offset, disk_bytenr, &sum);
184 if (ret == 0)
185 goto found;
186
187 if (!item || disk_bytenr < item_start_offset ||
188 disk_bytenr >= item_last_offset) {
189 struct btrfs_key found_key;
190 u32 item_size;
191
192 if (item)
193 btrfs_release_path(root, path);
194 item = btrfs_lookup_csum(NULL, root->fs_info->csum_root,
195 path, disk_bytenr, 0);
196 if (IS_ERR(item)) {
197 ret = PTR_ERR(item);
198 if (ret == -ENOENT || ret == -EFBIG)
199 ret = 0;
200 sum = 0;
201 if (BTRFS_I(inode)->root->root_key.objectid ==
202 BTRFS_DATA_RELOC_TREE_OBJECTID) {
203 set_extent_bits(io_tree, offset,
204 offset + bvec->bv_len - 1,
205 EXTENT_NODATASUM, GFP_NOFS);
206 } else {
207 printk(KERN_INFO "btrfs no csum found "
208 "for inode %lu start %llu\n",
209 inode->i_ino,
210 (unsigned long long)offset);
211 }
212 item = NULL;
213 btrfs_release_path(root, path);
214 goto found;
215 }
216 btrfs_item_key_to_cpu(path->nodes[0], &found_key,
217 path->slots[0]);
218
219 item_start_offset = found_key.offset;
220 item_size = btrfs_item_size_nr(path->nodes[0],
221 path->slots[0]);
222 item_last_offset = item_start_offset +
223 (item_size / csum_size) *
224 root->sectorsize;
225 item = btrfs_item_ptr(path->nodes[0], path->slots[0],
226 struct btrfs_csum_item);
227 }
228 /*
229 * this byte range must be able to fit inside
230 * a single leaf so it will also fit inside a u32
231 */
232 diff = disk_bytenr - item_start_offset;
233 diff = diff / root->sectorsize;
234 diff = diff * csum_size;
235
236 read_extent_buffer(path->nodes[0], &sum,
237 ((unsigned long)item) + diff,
238 csum_size);
239 found:
240 if (dst)
241 *dst++ = sum;
242 else
243 set_state_private(io_tree, offset, sum);
244 disk_bytenr += bvec->bv_len;
245 offset += bvec->bv_len;
246 bio_index++;
247 bvec++;
248 }
249 btrfs_free_path(path);
250 return 0;
251 }
252
253 int btrfs_lookup_bio_sums(struct btrfs_root *root, struct inode *inode,
254 struct bio *bio, u32 *dst)
255 {
256 return __btrfs_lookup_bio_sums(root, inode, bio, 0, dst, 0);
257 }
258
259 int btrfs_lookup_bio_sums_dio(struct btrfs_root *root, struct inode *inode,
260 struct bio *bio, u64 offset, u32 *dst)
261 {
262 return __btrfs_lookup_bio_sums(root, inode, bio, offset, dst, 1);
263 }
264
265 int btrfs_lookup_csums_range(struct btrfs_root *root, u64 start, u64 end,
266 struct list_head *list)
267 {
268 struct btrfs_key key;
269 struct btrfs_path *path;
270 struct extent_buffer *leaf;
271 struct btrfs_ordered_sum *sums;
272 struct btrfs_sector_sum *sector_sum;
273 struct btrfs_csum_item *item;
274 unsigned long offset;
275 int ret;
276 size_t size;
277 u64 csum_end;
278 u16 csum_size = btrfs_super_csum_size(&root->fs_info->super_copy);
279
280 path = btrfs_alloc_path();
281 BUG_ON(!path);
282
283 key.objectid = BTRFS_EXTENT_CSUM_OBJECTID;
284 key.offset = start;
285 key.type = BTRFS_EXTENT_CSUM_KEY;
286
287 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
288 if (ret < 0)
289 goto fail;
290 if (ret > 0 && path->slots[0] > 0) {
291 leaf = path->nodes[0];
292 btrfs_item_key_to_cpu(leaf, &key, path->slots[0] - 1);
293 if (key.objectid == BTRFS_EXTENT_CSUM_OBJECTID &&
294 key.type == BTRFS_EXTENT_CSUM_KEY) {
295 offset = (start - key.offset) >>
296 root->fs_info->sb->s_blocksize_bits;
297 if (offset * csum_size <
298 btrfs_item_size_nr(leaf, path->slots[0] - 1))
299 path->slots[0]--;
300 }
301 }
302
303 while (start <= end) {
304 leaf = path->nodes[0];
305 if (path->slots[0] >= btrfs_header_nritems(leaf)) {
306 ret = btrfs_next_leaf(root, path);
307 if (ret < 0)
308 goto fail;
309 if (ret > 0)
310 break;
311 leaf = path->nodes[0];
312 }
313
314 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
315 if (key.objectid != BTRFS_EXTENT_CSUM_OBJECTID ||
316 key.type != BTRFS_EXTENT_CSUM_KEY)
317 break;
318
319 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
320 if (key.offset > end)
321 break;
322
323 if (key.offset > start)
324 start = key.offset;
325
326 size = btrfs_item_size_nr(leaf, path->slots[0]);
327 csum_end = key.offset + (size / csum_size) * root->sectorsize;
328 if (csum_end <= start) {
329 path->slots[0]++;
330 continue;
331 }
332
333 csum_end = min(csum_end, end + 1);
334 item = btrfs_item_ptr(path->nodes[0], path->slots[0],
335 struct btrfs_csum_item);
336 while (start < csum_end) {
337 size = min_t(size_t, csum_end - start,
338 MAX_ORDERED_SUM_BYTES(root));
339 sums = kzalloc(btrfs_ordered_sum_size(root, size),
340 GFP_NOFS);
341 BUG_ON(!sums);
342
343 sector_sum = sums->sums;
344 sums->bytenr = start;
345 sums->len = size;
346
347 offset = (start - key.offset) >>
348 root->fs_info->sb->s_blocksize_bits;
349 offset *= csum_size;
350
351 while (size > 0) {
352 read_extent_buffer(path->nodes[0],
353 &sector_sum->sum,
354 ((unsigned long)item) +
355 offset, csum_size);
356 sector_sum->bytenr = start;
357
358 size -= root->sectorsize;
359 start += root->sectorsize;
360 offset += csum_size;
361 sector_sum++;
362 }
363 list_add_tail(&sums->list, list);
364 }
365 path->slots[0]++;
366 }
367 ret = 0;
368 fail:
369 btrfs_free_path(path);
370 return ret;
371 }
372
373 int btrfs_csum_one_bio(struct btrfs_root *root, struct inode *inode,
374 struct bio *bio, u64 file_start, int contig)
375 {
376 struct btrfs_ordered_sum *sums;
377 struct btrfs_sector_sum *sector_sum;
378 struct btrfs_ordered_extent *ordered;
379 char *data;
380 struct bio_vec *bvec = bio->bi_io_vec;
381 int bio_index = 0;
382 unsigned long total_bytes = 0;
383 unsigned long this_sum_bytes = 0;
384 u64 offset;
385 u64 disk_bytenr;
386
387 WARN_ON(bio->bi_vcnt <= 0);
388 sums = kzalloc(btrfs_ordered_sum_size(root, bio->bi_size), GFP_NOFS);
389 if (!sums)
390 return -ENOMEM;
391
392 sector_sum = sums->sums;
393 disk_bytenr = (u64)bio->bi_sector << 9;
394 sums->len = bio->bi_size;
395 INIT_LIST_HEAD(&sums->list);
396
397 if (contig)
398 offset = file_start;
399 else
400 offset = page_offset(bvec->bv_page) + bvec->bv_offset;
401
402 ordered = btrfs_lookup_ordered_extent(inode, offset);
403 BUG_ON(!ordered);
404 sums->bytenr = ordered->start;
405
406 while (bio_index < bio->bi_vcnt) {
407 if (!contig)
408 offset = page_offset(bvec->bv_page) + bvec->bv_offset;
409
410 if (!contig && (offset >= ordered->file_offset + ordered->len ||
411 offset < ordered->file_offset)) {
412 unsigned long bytes_left;
413 sums->len = this_sum_bytes;
414 this_sum_bytes = 0;
415 btrfs_add_ordered_sum(inode, ordered, sums);
416 btrfs_put_ordered_extent(ordered);
417
418 bytes_left = bio->bi_size - total_bytes;
419
420 sums = kzalloc(btrfs_ordered_sum_size(root, bytes_left),
421 GFP_NOFS);
422 BUG_ON(!sums);
423 sector_sum = sums->sums;
424 sums->len = bytes_left;
425 ordered = btrfs_lookup_ordered_extent(inode, offset);
426 BUG_ON(!ordered);
427 sums->bytenr = ordered->start;
428 }
429
430 data = kmap_atomic(bvec->bv_page, KM_USER0);
431 sector_sum->sum = ~(u32)0;
432 sector_sum->sum = btrfs_csum_data(root,
433 data + bvec->bv_offset,
434 sector_sum->sum,
435 bvec->bv_len);
436 kunmap_atomic(data, KM_USER0);
437 btrfs_csum_final(sector_sum->sum,
438 (char *)&sector_sum->sum);
439 sector_sum->bytenr = disk_bytenr;
440
441 sector_sum++;
442 bio_index++;
443 total_bytes += bvec->bv_len;
444 this_sum_bytes += bvec->bv_len;
445 disk_bytenr += bvec->bv_len;
446 offset += bvec->bv_len;
447 bvec++;
448 }
449 this_sum_bytes = 0;
450 btrfs_add_ordered_sum(inode, ordered, sums);
451 btrfs_put_ordered_extent(ordered);
452 return 0;
453 }
454
455 /*
456 * helper function for csum removal, this expects the
457 * key to describe the csum pointed to by the path, and it expects
458 * the csum to overlap the range [bytenr, len]
459 *
460 * The csum should not be entirely contained in the range and the
461 * range should not be entirely contained in the csum.
462 *
463 * This calls btrfs_truncate_item with the correct args based on the
464 * overlap, and fixes up the key as required.
465 */
466 static noinline int truncate_one_csum(struct btrfs_trans_handle *trans,
467 struct btrfs_root *root,
468 struct btrfs_path *path,
469 struct btrfs_key *key,
470 u64 bytenr, u64 len)
471 {
472 struct extent_buffer *leaf;
473 u16 csum_size =
474 btrfs_super_csum_size(&root->fs_info->super_copy);
475 u64 csum_end;
476 u64 end_byte = bytenr + len;
477 u32 blocksize_bits = root->fs_info->sb->s_blocksize_bits;
478 int ret;
479
480 leaf = path->nodes[0];
481 csum_end = btrfs_item_size_nr(leaf, path->slots[0]) / csum_size;
482 csum_end <<= root->fs_info->sb->s_blocksize_bits;
483 csum_end += key->offset;
484
485 if (key->offset < bytenr && csum_end <= end_byte) {
486 /*
487 * [ bytenr - len ]
488 * [ ]
489 * [csum ]
490 * A simple truncate off the end of the item
491 */
492 u32 new_size = (bytenr - key->offset) >> blocksize_bits;
493 new_size *= csum_size;
494 ret = btrfs_truncate_item(trans, root, path, new_size, 1);
495 BUG_ON(ret);
496 } else if (key->offset >= bytenr && csum_end > end_byte &&
497 end_byte > key->offset) {
498 /*
499 * [ bytenr - len ]
500 * [ ]
501 * [csum ]
502 * we need to truncate from the beginning of the csum
503 */
504 u32 new_size = (csum_end - end_byte) >> blocksize_bits;
505 new_size *= csum_size;
506
507 ret = btrfs_truncate_item(trans, root, path, new_size, 0);
508 BUG_ON(ret);
509
510 key->offset = end_byte;
511 ret = btrfs_set_item_key_safe(trans, root, path, key);
512 BUG_ON(ret);
513 } else {
514 BUG();
515 }
516 return 0;
517 }
518
519 /*
520 * deletes the csum items from the csum tree for a given
521 * range of bytes.
522 */
523 int btrfs_del_csums(struct btrfs_trans_handle *trans,
524 struct btrfs_root *root, u64 bytenr, u64 len)
525 {
526 struct btrfs_path *path;
527 struct btrfs_key key;
528 u64 end_byte = bytenr + len;
529 u64 csum_end;
530 struct extent_buffer *leaf;
531 int ret;
532 u16 csum_size =
533 btrfs_super_csum_size(&root->fs_info->super_copy);
534 int blocksize_bits = root->fs_info->sb->s_blocksize_bits;
535
536 root = root->fs_info->csum_root;
537
538 path = btrfs_alloc_path();
539
540 while (1) {
541 key.objectid = BTRFS_EXTENT_CSUM_OBJECTID;
542 key.offset = end_byte - 1;
543 key.type = BTRFS_EXTENT_CSUM_KEY;
544
545 path->leave_spinning = 1;
546 ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
547 if (ret > 0) {
548 if (path->slots[0] == 0)
549 goto out;
550 path->slots[0]--;
551 }
552 leaf = path->nodes[0];
553 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
554
555 if (key.objectid != BTRFS_EXTENT_CSUM_OBJECTID ||
556 key.type != BTRFS_EXTENT_CSUM_KEY) {
557 break;
558 }
559
560 if (key.offset >= end_byte)
561 break;
562
563 csum_end = btrfs_item_size_nr(leaf, path->slots[0]) / csum_size;
564 csum_end <<= blocksize_bits;
565 csum_end += key.offset;
566
567 /* this csum ends before we start, we're done */
568 if (csum_end <= bytenr)
569 break;
570
571 /* delete the entire item, it is inside our range */
572 if (key.offset >= bytenr && csum_end <= end_byte) {
573 ret = btrfs_del_item(trans, root, path);
574 BUG_ON(ret);
575 if (key.offset == bytenr)
576 break;
577 } else if (key.offset < bytenr && csum_end > end_byte) {
578 unsigned long offset;
579 unsigned long shift_len;
580 unsigned long item_offset;
581 /*
582 * [ bytenr - len ]
583 * [csum ]
584 *
585 * Our bytes are in the middle of the csum,
586 * we need to split this item and insert a new one.
587 *
588 * But we can't drop the path because the
589 * csum could change, get removed, extended etc.
590 *
591 * The trick here is the max size of a csum item leaves
592 * enough room in the tree block for a single
593 * item header. So, we split the item in place,
594 * adding a new header pointing to the existing
595 * bytes. Then we loop around again and we have
596 * a nicely formed csum item that we can neatly
597 * truncate.
598 */
599 offset = (bytenr - key.offset) >> blocksize_bits;
600 offset *= csum_size;
601
602 shift_len = (len >> blocksize_bits) * csum_size;
603
604 item_offset = btrfs_item_ptr_offset(leaf,
605 path->slots[0]);
606
607 memset_extent_buffer(leaf, 0, item_offset + offset,
608 shift_len);
609 key.offset = bytenr;
610
611 /*
612 * btrfs_split_item returns -EAGAIN when the
613 * item changed size or key
614 */
615 ret = btrfs_split_item(trans, root, path, &key, offset);
616 BUG_ON(ret && ret != -EAGAIN);
617
618 key.offset = end_byte - 1;
619 } else {
620 ret = truncate_one_csum(trans, root, path,
621 &key, bytenr, len);
622 BUG_ON(ret);
623 if (key.offset < bytenr)
624 break;
625 }
626 btrfs_release_path(root, path);
627 }
628 out:
629 btrfs_free_path(path);
630 return 0;
631 }
632
633 int btrfs_csum_file_blocks(struct btrfs_trans_handle *trans,
634 struct btrfs_root *root,
635 struct btrfs_ordered_sum *sums)
636 {
637 u64 bytenr;
638 int ret;
639 struct btrfs_key file_key;
640 struct btrfs_key found_key;
641 u64 next_offset;
642 u64 total_bytes = 0;
643 int found_next;
644 struct btrfs_path *path;
645 struct btrfs_csum_item *item;
646 struct btrfs_csum_item *item_end;
647 struct extent_buffer *leaf = NULL;
648 u64 csum_offset;
649 struct btrfs_sector_sum *sector_sum;
650 u32 nritems;
651 u32 ins_size;
652 char *eb_map;
653 char *eb_token;
654 unsigned long map_len;
655 unsigned long map_start;
656 u16 csum_size =
657 btrfs_super_csum_size(&root->fs_info->super_copy);
658
659 path = btrfs_alloc_path();
660 BUG_ON(!path);
661 sector_sum = sums->sums;
662 again:
663 next_offset = (u64)-1;
664 found_next = 0;
665 file_key.objectid = BTRFS_EXTENT_CSUM_OBJECTID;
666 file_key.offset = sector_sum->bytenr;
667 bytenr = sector_sum->bytenr;
668 btrfs_set_key_type(&file_key, BTRFS_EXTENT_CSUM_KEY);
669
670 item = btrfs_lookup_csum(trans, root, path, sector_sum->bytenr, 1);
671 if (!IS_ERR(item)) {
672 leaf = path->nodes[0];
673 ret = 0;
674 goto found;
675 }
676 ret = PTR_ERR(item);
677 if (ret != -EFBIG && ret != -ENOENT)
678 goto fail_unlock;
679
680 if (ret == -EFBIG) {
681 u32 item_size;
682 /* we found one, but it isn't big enough yet */
683 leaf = path->nodes[0];
684 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
685 if ((item_size / csum_size) >=
686 MAX_CSUM_ITEMS(root, csum_size)) {
687 /* already at max size, make a new one */
688 goto insert;
689 }
690 } else {
691 int slot = path->slots[0] + 1;
692 /* we didn't find a csum item, insert one */
693 nritems = btrfs_header_nritems(path->nodes[0]);
694 if (path->slots[0] >= nritems - 1) {
695 ret = btrfs_next_leaf(root, path);
696 if (ret == 1)
697 found_next = 1;
698 if (ret != 0)
699 goto insert;
700 slot = 0;
701 }
702 btrfs_item_key_to_cpu(path->nodes[0], &found_key, slot);
703 if (found_key.objectid != BTRFS_EXTENT_CSUM_OBJECTID ||
704 found_key.type != BTRFS_EXTENT_CSUM_KEY) {
705 found_next = 1;
706 goto insert;
707 }
708 next_offset = found_key.offset;
709 found_next = 1;
710 goto insert;
711 }
712
713 /*
714 * at this point, we know the tree has an item, but it isn't big
715 * enough yet to put our csum in. Grow it
716 */
717 btrfs_release_path(root, path);
718 ret = btrfs_search_slot(trans, root, &file_key, path,
719 csum_size, 1);
720 if (ret < 0)
721 goto fail_unlock;
722
723 if (ret > 0) {
724 if (path->slots[0] == 0)
725 goto insert;
726 path->slots[0]--;
727 }
728
729 leaf = path->nodes[0];
730 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
731 csum_offset = (bytenr - found_key.offset) >>
732 root->fs_info->sb->s_blocksize_bits;
733
734 if (btrfs_key_type(&found_key) != BTRFS_EXTENT_CSUM_KEY ||
735 found_key.objectid != BTRFS_EXTENT_CSUM_OBJECTID ||
736 csum_offset >= MAX_CSUM_ITEMS(root, csum_size)) {
737 goto insert;
738 }
739
740 if (csum_offset >= btrfs_item_size_nr(leaf, path->slots[0]) /
741 csum_size) {
742 u32 diff = (csum_offset + 1) * csum_size;
743
744 /*
745 * is the item big enough already? we dropped our lock
746 * before and need to recheck
747 */
748 if (diff < btrfs_item_size_nr(leaf, path->slots[0]))
749 goto csum;
750
751 diff = diff - btrfs_item_size_nr(leaf, path->slots[0]);
752 if (diff != csum_size)
753 goto insert;
754
755 ret = btrfs_extend_item(trans, root, path, diff);
756 BUG_ON(ret);
757 goto csum;
758 }
759
760 insert:
761 btrfs_release_path(root, path);
762 csum_offset = 0;
763 if (found_next) {
764 u64 tmp = total_bytes + root->sectorsize;
765 u64 next_sector = sector_sum->bytenr;
766 struct btrfs_sector_sum *next = sector_sum + 1;
767
768 while (tmp < sums->len) {
769 if (next_sector + root->sectorsize != next->bytenr)
770 break;
771 tmp += root->sectorsize;
772 next_sector = next->bytenr;
773 next++;
774 }
775 tmp = min(tmp, next_offset - file_key.offset);
776 tmp >>= root->fs_info->sb->s_blocksize_bits;
777 tmp = max((u64)1, tmp);
778 tmp = min(tmp, (u64)MAX_CSUM_ITEMS(root, csum_size));
779 ins_size = csum_size * tmp;
780 } else {
781 ins_size = csum_size;
782 }
783 path->leave_spinning = 1;
784 ret = btrfs_insert_empty_item(trans, root, path, &file_key,
785 ins_size);
786 path->leave_spinning = 0;
787 if (ret < 0)
788 goto fail_unlock;
789 if (ret != 0) {
790 WARN_ON(1);
791 goto fail_unlock;
792 }
793 csum:
794 leaf = path->nodes[0];
795 item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_csum_item);
796 ret = 0;
797 item = (struct btrfs_csum_item *)((unsigned char *)item +
798 csum_offset * csum_size);
799 found:
800 item_end = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_csum_item);
801 item_end = (struct btrfs_csum_item *)((unsigned char *)item_end +
802 btrfs_item_size_nr(leaf, path->slots[0]));
803 eb_token = NULL;
804 next_sector:
805
806 if (!eb_token ||
807 (unsigned long)item + csum_size >= map_start + map_len) {
808 int err;
809
810 if (eb_token)
811 unmap_extent_buffer(leaf, eb_token, KM_USER1);
812 eb_token = NULL;
813 err = map_private_extent_buffer(leaf, (unsigned long)item,
814 csum_size,
815 &eb_token, &eb_map,
816 &map_start, &map_len, KM_USER1);
817 if (err)
818 eb_token = NULL;
819 }
820 if (eb_token) {
821 memcpy(eb_token + ((unsigned long)item & (PAGE_CACHE_SIZE - 1)),
822 &sector_sum->sum, csum_size);
823 } else {
824 write_extent_buffer(leaf, &sector_sum->sum,
825 (unsigned long)item, csum_size);
826 }
827
828 total_bytes += root->sectorsize;
829 sector_sum++;
830 if (total_bytes < sums->len) {
831 item = (struct btrfs_csum_item *)((char *)item +
832 csum_size);
833 if (item < item_end && bytenr + PAGE_CACHE_SIZE ==
834 sector_sum->bytenr) {
835 bytenr = sector_sum->bytenr;
836 goto next_sector;
837 }
838 }
839 if (eb_token) {
840 unmap_extent_buffer(leaf, eb_token, KM_USER1);
841 eb_token = NULL;
842 }
843 btrfs_mark_buffer_dirty(path->nodes[0]);
844 if (total_bytes < sums->len) {
845 btrfs_release_path(root, path);
846 cond_resched();
847 goto again;
848 }
849 out:
850 btrfs_free_path(path);
851 return ret;
852
853 fail_unlock:
854 goto out;
855 }
Tomato firmware and modifications.