projects / GitHub / mt8127 / android_kernel_alcatel_ttab.git / blob
? search:
summary | shortlog | log | commit | commitdiff | tree
blame | history | raw | HEAD
Merge branch 'cleanups' of git://repo.or.cz/linux-2.6/btrfs-unstable into inode_numbers
[GitHub/mt8127/android_kernel_alcatel_ttab.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)
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 BUG_ON(!path);
286
287 key.objectid = BTRFS_EXTENT_CSUM_OBJECTID;
288 key.offset = start;
289 key.type = BTRFS_EXTENT_CSUM_KEY;
290
291 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
292 if (ret < 0)
293 goto fail;
294 if (ret > 0 && path->slots[0] > 0) {
295 leaf = path->nodes[0];
296 btrfs_item_key_to_cpu(leaf, &key, path->slots[0] - 1);
297 if (key.objectid == BTRFS_EXTENT_CSUM_OBJECTID &&
298 key.type == BTRFS_EXTENT_CSUM_KEY) {
299 offset = (start - key.offset) >>
300 root->fs_info->sb->s_blocksize_bits;
301 if (offset * csum_size <
302 btrfs_item_size_nr(leaf, path->slots[0] - 1))
303 path->slots[0]--;
304 }
305 }
306
307 while (start <= end) {
308 leaf = path->nodes[0];
309 if (path->slots[0] >= btrfs_header_nritems(leaf)) {
310 ret = btrfs_next_leaf(root, path);
311 if (ret < 0)
312 goto fail;
313 if (ret > 0)
314 break;
315 leaf = path->nodes[0];
316 }
317
318 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
319 if (key.objectid != BTRFS_EXTENT_CSUM_OBJECTID ||
320 key.type != BTRFS_EXTENT_CSUM_KEY)
321 break;
322
323 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
324 if (key.offset > end)
325 break;
326
327 if (key.offset > start)
328 start = key.offset;
329
330 size = btrfs_item_size_nr(leaf, path->slots[0]);
331 csum_end = key.offset + (size / csum_size) * root->sectorsize;
332 if (csum_end <= start) {
333 path->slots[0]++;
334 continue;
335 }
336
337 csum_end = min(csum_end, end + 1);
338 item = btrfs_item_ptr(path->nodes[0], path->slots[0],
339 struct btrfs_csum_item);
340 while (start < csum_end) {
341 size = min_t(size_t, csum_end - start,
342 MAX_ORDERED_SUM_BYTES(root));
343 sums = kzalloc(btrfs_ordered_sum_size(root, size),
344 GFP_NOFS);
345 BUG_ON(!sums);
346
347 sector_sum = sums->sums;
348 sums->bytenr = start;
349 sums->len = size;
350
351 offset = (start - key.offset) >>
352 root->fs_info->sb->s_blocksize_bits;
353 offset *= csum_size;
354
355 while (size > 0) {
356 read_extent_buffer(path->nodes[0],
357 &sector_sum->sum,
358 ((unsigned long)item) +
359 offset, csum_size);
360 sector_sum->bytenr = start;
361
362 size -= root->sectorsize;
363 start += root->sectorsize;
364 offset += csum_size;
365 sector_sum++;
366 }
367 list_add_tail(&sums->list, list);
368 }
369 path->slots[0]++;
370 }
371 ret = 0;
372 fail:
373 btrfs_free_path(path);
374 return ret;
375 }
376
377 int btrfs_csum_one_bio(struct btrfs_root *root, struct inode *inode,
378 struct bio *bio, u64 file_start, int contig)
379 {
380 struct btrfs_ordered_sum *sums;
381 struct btrfs_sector_sum *sector_sum;
382 struct btrfs_ordered_extent *ordered;
383 char *data;
384 struct bio_vec *bvec = bio->bi_io_vec;
385 int bio_index = 0;
386 unsigned long total_bytes = 0;
387 unsigned long this_sum_bytes = 0;
388 u64 offset;
389 u64 disk_bytenr;
390
391 WARN_ON(bio->bi_vcnt <= 0);
392 sums = kzalloc(btrfs_ordered_sum_size(root, bio->bi_size), GFP_NOFS);
393 if (!sums)
394 return -ENOMEM;
395
396 sector_sum = sums->sums;
397 disk_bytenr = (u64)bio->bi_sector << 9;
398 sums->len = bio->bi_size;
399 INIT_LIST_HEAD(&sums->list);
400
401 if (contig)
402 offset = file_start;
403 else
404 offset = page_offset(bvec->bv_page) + bvec->bv_offset;
405
406 ordered = btrfs_lookup_ordered_extent(inode, offset);
407 BUG_ON(!ordered);
408 sums->bytenr = ordered->start;
409
410 while (bio_index < bio->bi_vcnt) {
411 if (!contig)
412 offset = page_offset(bvec->bv_page) + bvec->bv_offset;
413
414 if (!contig && (offset >= ordered->file_offset + ordered->len ||
415 offset < ordered->file_offset)) {
416 unsigned long bytes_left;
417 sums->len = this_sum_bytes;
418 this_sum_bytes = 0;
419 btrfs_add_ordered_sum(inode, ordered, sums);
420 btrfs_put_ordered_extent(ordered);
421
422 bytes_left = bio->bi_size - total_bytes;
423
424 sums = kzalloc(btrfs_ordered_sum_size(root, bytes_left),
425 GFP_NOFS);
426 BUG_ON(!sums);
427 sector_sum = sums->sums;
428 sums->len = bytes_left;
429 ordered = btrfs_lookup_ordered_extent(inode, offset);
430 BUG_ON(!ordered);
431 sums->bytenr = ordered->start;
432 }
433
434 data = kmap_atomic(bvec->bv_page, KM_USER0);
435 sector_sum->sum = ~(u32)0;
436 sector_sum->sum = btrfs_csum_data(root,
437 data + bvec->bv_offset,
438 sector_sum->sum,
439 bvec->bv_len);
440 kunmap_atomic(data, KM_USER0);
441 btrfs_csum_final(sector_sum->sum,
442 (char *)&sector_sum->sum);
443 sector_sum->bytenr = disk_bytenr;
444
445 sector_sum++;
446 bio_index++;
447 total_bytes += bvec->bv_len;
448 this_sum_bytes += bvec->bv_len;
449 disk_bytenr += bvec->bv_len;
450 offset += bvec->bv_len;
451 bvec++;
452 }
453 this_sum_bytes = 0;
454 btrfs_add_ordered_sum(inode, ordered, sums);
455 btrfs_put_ordered_extent(ordered);
456 return 0;
457 }
458
459 /*
460 * helper function for csum removal, this expects the
461 * key to describe the csum pointed to by the path, and it expects
462 * the csum to overlap the range [bytenr, len]
463 *
464 * The csum should not be entirely contained in the range and the
465 * range should not be entirely contained in the csum.
466 *
467 * This calls btrfs_truncate_item with the correct args based on the
468 * overlap, and fixes up the key as required.
469 */
470 static noinline int truncate_one_csum(struct btrfs_trans_handle *trans,
471 struct btrfs_root *root,
472 struct btrfs_path *path,
473 struct btrfs_key *key,
474 u64 bytenr, u64 len)
475 {
476 struct extent_buffer *leaf;
477 u16 csum_size =
478 btrfs_super_csum_size(&root->fs_info->super_copy);
479 u64 csum_end;
480 u64 end_byte = bytenr + len;
481 u32 blocksize_bits = root->fs_info->sb->s_blocksize_bits;
482 int ret;
483
484 leaf = path->nodes[0];
485 csum_end = btrfs_item_size_nr(leaf, path->slots[0]) / csum_size;
486 csum_end <<= root->fs_info->sb->s_blocksize_bits;
487 csum_end += key->offset;
488
489 if (key->offset < bytenr && csum_end <= end_byte) {
490 /*
491 * [ bytenr - len ]
492 * [ ]
493 * [csum ]
494 * A simple truncate off the end of the item
495 */
496 u32 new_size = (bytenr - key->offset) >> blocksize_bits;
497 new_size *= csum_size;
498 ret = btrfs_truncate_item(trans, root, path, new_size, 1);
499 BUG_ON(ret);
500 } else if (key->offset >= bytenr && csum_end > end_byte &&
501 end_byte > key->offset) {
502 /*
503 * [ bytenr - len ]
504 * [ ]
505 * [csum ]
506 * we need to truncate from the beginning of the csum
507 */
508 u32 new_size = (csum_end - end_byte) >> blocksize_bits;
509 new_size *= csum_size;
510
511 ret = btrfs_truncate_item(trans, root, path, new_size, 0);
512 BUG_ON(ret);
513
514 key->offset = end_byte;
515 ret = btrfs_set_item_key_safe(trans, root, path, key);
516 BUG_ON(ret);
517 } else {
518 BUG();
519 }
520 return 0;
521 }
522
523 /*
524 * deletes the csum items from the csum tree for a given
525 * range of bytes.
526 */
527 int btrfs_del_csums(struct btrfs_trans_handle *trans,
528 struct btrfs_root *root, u64 bytenr, u64 len)
529 {
530 struct btrfs_path *path;
531 struct btrfs_key key;
532 u64 end_byte = bytenr + len;
533 u64 csum_end;
534 struct extent_buffer *leaf;
535 int ret;
536 u16 csum_size =
537 btrfs_super_csum_size(&root->fs_info->super_copy);
538 int blocksize_bits = root->fs_info->sb->s_blocksize_bits;
539
540 root = root->fs_info->csum_root;
541
542 path = btrfs_alloc_path();
543 if (!path)
544 return -ENOMEM;
545
546 while (1) {
547 key.objectid = BTRFS_EXTENT_CSUM_OBJECTID;
548 key.offset = end_byte - 1;
549 key.type = BTRFS_EXTENT_CSUM_KEY;
550
551 path->leave_spinning = 1;
552 ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
553 if (ret > 0) {
554 if (path->slots[0] == 0)
555 goto out;
556 path->slots[0]--;
557 } else if (ret < 0) {
558 goto out;
559 }
560
561 leaf = path->nodes[0];
562 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
563
564 if (key.objectid != BTRFS_EXTENT_CSUM_OBJECTID ||
565 key.type != BTRFS_EXTENT_CSUM_KEY) {
566 break;
567 }
568
569 if (key.offset >= end_byte)
570 break;
571
572 csum_end = btrfs_item_size_nr(leaf, path->slots[0]) / csum_size;
573 csum_end <<= blocksize_bits;
574 csum_end += key.offset;
575
576 /* this csum ends before we start, we're done */
577 if (csum_end <= bytenr)
578 break;
579
580 /* delete the entire item, it is inside our range */
581 if (key.offset >= bytenr && csum_end <= end_byte) {
582 ret = btrfs_del_item(trans, root, path);
583 BUG_ON(ret);
584 if (key.offset == bytenr)
585 break;
586 } else if (key.offset < bytenr && csum_end > end_byte) {
587 unsigned long offset;
588 unsigned long shift_len;
589 unsigned long item_offset;
590 /*
591 * [ bytenr - len ]
592 * [csum ]
593 *
594 * Our bytes are in the middle of the csum,
595 * we need to split this item and insert a new one.
596 *
597 * But we can't drop the path because the
598 * csum could change, get removed, extended etc.
599 *
600 * The trick here is the max size of a csum item leaves
601 * enough room in the tree block for a single
602 * item header. So, we split the item in place,
603 * adding a new header pointing to the existing
604 * bytes. Then we loop around again and we have
605 * a nicely formed csum item that we can neatly
606 * truncate.
607 */
608 offset = (bytenr - key.offset) >> blocksize_bits;
609 offset *= csum_size;
610
611 shift_len = (len >> blocksize_bits) * csum_size;
612
613 item_offset = btrfs_item_ptr_offset(leaf,
614 path->slots[0]);
615
616 memset_extent_buffer(leaf, 0, item_offset + offset,
617 shift_len);
618 key.offset = bytenr;
619
620 /*
621 * btrfs_split_item returns -EAGAIN when the
622 * item changed size or key
623 */
624 ret = btrfs_split_item(trans, root, path, &key, offset);
625 BUG_ON(ret && ret != -EAGAIN);
626
627 key.offset = end_byte - 1;
628 } else {
629 ret = truncate_one_csum(trans, root, path,
630 &key, bytenr, len);
631 BUG_ON(ret);
632 if (key.offset < bytenr)
633 break;
634 }
635 btrfs_release_path(path);
636 }
637 out:
638 btrfs_free_path(path);
639 return 0;
640 }
641
642 int btrfs_csum_file_blocks(struct btrfs_trans_handle *trans,
643 struct btrfs_root *root,
644 struct btrfs_ordered_sum *sums)
645 {
646 u64 bytenr;
647 int ret;
648 struct btrfs_key file_key;
649 struct btrfs_key found_key;
650 u64 next_offset;
651 u64 total_bytes = 0;
652 int found_next;
653 struct btrfs_path *path;
654 struct btrfs_csum_item *item;
655 struct btrfs_csum_item *item_end;
656 struct extent_buffer *leaf = NULL;
657 u64 csum_offset;
658 struct btrfs_sector_sum *sector_sum;
659 u32 nritems;
660 u32 ins_size;
661 char *eb_map;
662 char *eb_token;
663 unsigned long map_len;
664 unsigned long map_start;
665 u16 csum_size =
666 btrfs_super_csum_size(&root->fs_info->super_copy);
667
668 path = btrfs_alloc_path();
669 BUG_ON(!path);
670 sector_sum = sums->sums;
671 again:
672 next_offset = (u64)-1;
673 found_next = 0;
674 file_key.objectid = BTRFS_EXTENT_CSUM_OBJECTID;
675 file_key.offset = sector_sum->bytenr;
676 bytenr = sector_sum->bytenr;
677 btrfs_set_key_type(&file_key, BTRFS_EXTENT_CSUM_KEY);
678
679 item = btrfs_lookup_csum(trans, root, path, sector_sum->bytenr, 1);
680 if (!IS_ERR(item)) {
681 leaf = path->nodes[0];
682 ret = 0;
683 goto found;
684 }
685 ret = PTR_ERR(item);
686 if (ret != -EFBIG && ret != -ENOENT)
687 goto fail_unlock;
688
689 if (ret == -EFBIG) {
690 u32 item_size;
691 /* we found one, but it isn't big enough yet */
692 leaf = path->nodes[0];
693 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
694 if ((item_size / csum_size) >=
695 MAX_CSUM_ITEMS(root, csum_size)) {
696 /* already at max size, make a new one */
697 goto insert;
698 }
699 } else {
700 int slot = path->slots[0] + 1;
701 /* we didn't find a csum item, insert one */
702 nritems = btrfs_header_nritems(path->nodes[0]);
703 if (path->slots[0] >= nritems - 1) {
704 ret = btrfs_next_leaf(root, path);
705 if (ret == 1)
706 found_next = 1;
707 if (ret != 0)
708 goto insert;
709 slot = 0;
710 }
711 btrfs_item_key_to_cpu(path->nodes[0], &found_key, slot);
712 if (found_key.objectid != BTRFS_EXTENT_CSUM_OBJECTID ||
713 found_key.type != BTRFS_EXTENT_CSUM_KEY) {
714 found_next = 1;
715 goto insert;
716 }
717 next_offset = found_key.offset;
718 found_next = 1;
719 goto insert;
720 }
721
722 /*
723 * at this point, we know the tree has an item, but it isn't big
724 * enough yet to put our csum in. Grow it
725 */
726 btrfs_release_path(path);
727 ret = btrfs_search_slot(trans, root, &file_key, path,
728 csum_size, 1);
729 if (ret < 0)
730 goto fail_unlock;
731
732 if (ret > 0) {
733 if (path->slots[0] == 0)
734 goto insert;
735 path->slots[0]--;
736 }
737
738 leaf = path->nodes[0];
739 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
740 csum_offset = (bytenr - found_key.offset) >>
741 root->fs_info->sb->s_blocksize_bits;
742
743 if (btrfs_key_type(&found_key) != BTRFS_EXTENT_CSUM_KEY ||
744 found_key.objectid != BTRFS_EXTENT_CSUM_OBJECTID ||
745 csum_offset >= MAX_CSUM_ITEMS(root, csum_size)) {
746 goto insert;
747 }
748
749 if (csum_offset >= btrfs_item_size_nr(leaf, path->slots[0]) /
750 csum_size) {
751 u32 diff = (csum_offset + 1) * csum_size;
752
753 /*
754 * is the item big enough already? we dropped our lock
755 * before and need to recheck
756 */
757 if (diff < btrfs_item_size_nr(leaf, path->slots[0]))
758 goto csum;
759
760 diff = diff - btrfs_item_size_nr(leaf, path->slots[0]);
761 if (diff != csum_size)
762 goto insert;
763
764 ret = btrfs_extend_item(trans, root, path, diff);
765 BUG_ON(ret);
766 goto csum;
767 }
768
769 insert:
770 btrfs_release_path(path);
771 csum_offset = 0;
772 if (found_next) {
773 u64 tmp = total_bytes + root->sectorsize;
774 u64 next_sector = sector_sum->bytenr;
775 struct btrfs_sector_sum *next = sector_sum + 1;
776
777 while (tmp < sums->len) {
778 if (next_sector + root->sectorsize != next->bytenr)
779 break;
780 tmp += root->sectorsize;
781 next_sector = next->bytenr;
782 next++;
783 }
784 tmp = min(tmp, next_offset - file_key.offset);
785 tmp >>= root->fs_info->sb->s_blocksize_bits;
786 tmp = max((u64)1, tmp);
787 tmp = min(tmp, (u64)MAX_CSUM_ITEMS(root, csum_size));
788 ins_size = csum_size * tmp;
789 } else {
790 ins_size = csum_size;
791 }
792 path->leave_spinning = 1;
793 ret = btrfs_insert_empty_item(trans, root, path, &file_key,
794 ins_size);
795 path->leave_spinning = 0;
796 if (ret < 0)
797 goto fail_unlock;
798 if (ret != 0) {
799 WARN_ON(1);
800 goto fail_unlock;
801 }
802 csum:
803 leaf = path->nodes[0];
804 item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_csum_item);
805 ret = 0;
806 item = (struct btrfs_csum_item *)((unsigned char *)item +
807 csum_offset * csum_size);
808 found:
809 item_end = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_csum_item);
810 item_end = (struct btrfs_csum_item *)((unsigned char *)item_end +
811 btrfs_item_size_nr(leaf, path->slots[0]));
812 eb_token = NULL;
813 next_sector:
814
815 if (!eb_token ||
816 (unsigned long)item + csum_size >= map_start + map_len) {
817 int err;
818
819 if (eb_token)
820 unmap_extent_buffer(leaf, eb_token, KM_USER1);
821 eb_token = NULL;
822 err = map_private_extent_buffer(leaf, (unsigned long)item,
823 csum_size,
824 &eb_token, &eb_map,
825 &map_start, &map_len, KM_USER1);
826 if (err)
827 eb_token = NULL;
828 }
829 if (eb_token) {
830 memcpy(eb_token + ((unsigned long)item & (PAGE_CACHE_SIZE - 1)),
831 &sector_sum->sum, csum_size);
832 } else {
833 write_extent_buffer(leaf, &sector_sum->sum,
834 (unsigned long)item, csum_size);
835 }
836
837 total_bytes += root->sectorsize;
838 sector_sum++;
839 if (total_bytes < sums->len) {
840 item = (struct btrfs_csum_item *)((char *)item +
841 csum_size);
842 if (item < item_end && bytenr + PAGE_CACHE_SIZE ==
843 sector_sum->bytenr) {
844 bytenr = sector_sum->bytenr;
845 goto next_sector;
846 }
847 }
848 if (eb_token) {
849 unmap_extent_buffer(leaf, eb_token, KM_USER1);
850 eb_token = NULL;
851 }
852 btrfs_mark_buffer_dirty(path->nodes[0]);
853 if (total_bytes < sums->len) {
854 btrfs_release_path(path);
855 cond_resched();
856 goto again;
857 }
858 out:
859 btrfs_free_path(path);
860 return ret;
861
862 fail_unlock:
863 goto out;
864 }
kernel source for telekom puls (alcatel/mediatek)