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Btrfs: Add mount option to turn off data cow
[deliverable/linux.git] / fs / btrfs / extent-tree.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/sched.h>
20 #include <linux/crc32c.h>
21 #include "hash.h"
22 #include "ctree.h"
23 #include "disk-io.h"
24 #include "print-tree.h"
25 #include "transaction.h"
26
27 #define BLOCK_GROUP_DATA EXTENT_WRITEBACK
28 #define BLOCK_GROUP_METADATA EXTENT_UPTODATE
29 #define BLOCK_GROUP_DIRTY EXTENT_DIRTY
30
31 static int finish_current_insert(struct btrfs_trans_handle *trans, struct
32 btrfs_root *extent_root);
33 static int del_pending_extents(struct btrfs_trans_handle *trans, struct
34 btrfs_root *extent_root);
35
36 static int cache_block_group(struct btrfs_root *root,
37 struct btrfs_block_group_cache *block_group)
38 {
39 struct btrfs_path *path;
40 int ret;
41 struct btrfs_key key;
42 struct extent_buffer *leaf;
43 struct extent_map_tree *free_space_cache;
44 int slot;
45 u64 last = 0;
46 u64 hole_size;
47 u64 first_free;
48 int found = 0;
49
50 if (!block_group)
51 return 0;
52
53 root = root->fs_info->extent_root;
54 free_space_cache = &root->fs_info->free_space_cache;
55
56 if (block_group->cached)
57 return 0;
58
59 path = btrfs_alloc_path();
60 if (!path)
61 return -ENOMEM;
62
63 path->reada = 2;
64 first_free = block_group->key.objectid;
65 key.objectid = block_group->key.objectid;
66 key.offset = 0;
67
68 btrfs_set_key_type(&key, BTRFS_EXTENT_ITEM_KEY);
69 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
70
71 if (ret < 0)
72 return ret;
73
74 if (ret && path->slots[0] > 0)
75 path->slots[0]--;
76
77 while(1) {
78 leaf = path->nodes[0];
79 slot = path->slots[0];
80 if (slot >= btrfs_header_nritems(leaf)) {
81 ret = btrfs_next_leaf(root, path);
82 if (ret < 0)
83 goto err;
84 if (ret == 0) {
85 continue;
86 } else {
87 break;
88 }
89 }
90
91 btrfs_item_key_to_cpu(leaf, &key, slot);
92 if (key.objectid < block_group->key.objectid) {
93 if (btrfs_key_type(&key) != BTRFS_EXTENT_REF_KEY &&
94 key.objectid + key.offset > first_free)
95 first_free = key.objectid + key.offset;
96 goto next;
97 }
98
99 if (key.objectid >= block_group->key.objectid +
100 block_group->key.offset) {
101 break;
102 }
103
104 if (btrfs_key_type(&key) == BTRFS_EXTENT_ITEM_KEY) {
105 if (!found) {
106 last = first_free;
107 found = 1;
108 }
109 if (key.objectid > last) {
110 hole_size = key.objectid - last;
111 set_extent_dirty(free_space_cache, last,
112 last + hole_size - 1,
113 GFP_NOFS);
114 }
115 last = key.objectid + key.offset;
116 }
117 next:
118 path->slots[0]++;
119 }
120
121 if (!found)
122 last = first_free;
123 if (block_group->key.objectid +
124 block_group->key.offset > last) {
125 hole_size = block_group->key.objectid +
126 block_group->key.offset - last;
127 set_extent_dirty(free_space_cache, last,
128 last + hole_size - 1, GFP_NOFS);
129 }
130 block_group->cached = 1;
131 err:
132 btrfs_free_path(path);
133 return 0;
134 }
135
136 struct btrfs_block_group_cache *btrfs_lookup_block_group(struct
137 btrfs_fs_info *info,
138 u64 bytenr)
139 {
140 struct extent_map_tree *block_group_cache;
141 struct btrfs_block_group_cache *block_group = NULL;
142 u64 ptr;
143 u64 start;
144 u64 end;
145 int ret;
146
147 block_group_cache = &info->block_group_cache;
148 ret = find_first_extent_bit(block_group_cache,
149 bytenr, &start, &end,
150 BLOCK_GROUP_DATA | BLOCK_GROUP_METADATA);
151 if (ret) {
152 return NULL;
153 }
154 ret = get_state_private(block_group_cache, start, &ptr);
155 if (ret)
156 return NULL;
157
158 block_group = (struct btrfs_block_group_cache *)(unsigned long)ptr;
159 if (block_group->key.objectid <= bytenr && bytenr <
160 block_group->key.objectid + block_group->key.offset)
161 return block_group;
162 return NULL;
163 }
164 static u64 find_search_start(struct btrfs_root *root,
165 struct btrfs_block_group_cache **cache_ret,
166 u64 search_start, int num,
167 int data, int full_scan)
168 {
169 int ret;
170 struct btrfs_block_group_cache *cache = *cache_ret;
171 u64 last;
172 u64 start = 0;
173 u64 end = 0;
174 u64 cache_miss = 0;
175 int wrapped = 0;
176
177 if (!cache) {
178 goto out;
179 }
180 again:
181 ret = cache_block_group(root, cache);
182 if (ret)
183 goto out;
184
185 last = max(search_start, cache->key.objectid);
186
187 while(1) {
188 ret = find_first_extent_bit(&root->fs_info->free_space_cache,
189 last, &start, &end, EXTENT_DIRTY);
190 if (ret) {
191 if (!cache_miss)
192 cache_miss = last;
193 goto new_group;
194 }
195
196 start = max(last, start);
197 last = end + 1;
198 if (last - start < num) {
199 if (last == cache->key.objectid + cache->key.offset)
200 cache_miss = start;
201 continue;
202 }
203 if (data != BTRFS_BLOCK_GROUP_MIXED &&
204 start + num > cache->key.objectid + cache->key.offset)
205 goto new_group;
206 return start;
207 }
208 out:
209 cache = btrfs_lookup_block_group(root->fs_info, search_start);
210 if (!cache) {
211 printk("Unable to find block group for %Lu\n",
212 search_start);
213 WARN_ON(1);
214 return search_start;
215 }
216 return search_start;
217
218 new_group:
219 last = cache->key.objectid + cache->key.offset;
220 wrapped:
221 cache = btrfs_lookup_block_group(root->fs_info, last);
222 if (!cache) {
223 no_cache:
224 if (!wrapped) {
225 wrapped = 1;
226 last = search_start;
227 data = BTRFS_BLOCK_GROUP_MIXED;
228 goto wrapped;
229 }
230 goto out;
231 }
232 if (cache_miss && !cache->cached) {
233 cache_block_group(root, cache);
234 last = cache_miss;
235 cache = btrfs_lookup_block_group(root->fs_info, last);
236 }
237 cache = btrfs_find_block_group(root, cache, last, data, 0);
238 if (!cache)
239 goto no_cache;
240 *cache_ret = cache;
241 cache_miss = 0;
242 goto again;
243 }
244
245 static u64 div_factor(u64 num, int factor)
246 {
247 if (factor == 10)
248 return num;
249 num *= factor;
250 do_div(num, 10);
251 return num;
252 }
253
254 struct btrfs_block_group_cache *btrfs_find_block_group(struct btrfs_root *root,
255 struct btrfs_block_group_cache
256 *hint, u64 search_start,
257 int data, int owner)
258 {
259 struct btrfs_block_group_cache *cache;
260 struct extent_map_tree *block_group_cache;
261 struct btrfs_block_group_cache *found_group = NULL;
262 struct btrfs_fs_info *info = root->fs_info;
263 u64 used;
264 u64 last = 0;
265 u64 hint_last;
266 u64 start;
267 u64 end;
268 u64 free_check;
269 u64 ptr;
270 int bit;
271 int ret;
272 int full_search = 0;
273 int factor = 8;
274 int data_swap = 0;
275
276 block_group_cache = &info->block_group_cache;
277
278 if (!owner)
279 factor = 8;
280
281 if (data == BTRFS_BLOCK_GROUP_MIXED) {
282 bit = BLOCK_GROUP_DATA | BLOCK_GROUP_METADATA;
283 factor = 10;
284 } else if (data)
285 bit = BLOCK_GROUP_DATA;
286 else
287 bit = BLOCK_GROUP_METADATA;
288
289 if (search_start) {
290 struct btrfs_block_group_cache *shint;
291 shint = btrfs_lookup_block_group(info, search_start);
292 if (shint && (shint->data == data ||
293 shint->data == BTRFS_BLOCK_GROUP_MIXED)) {
294 used = btrfs_block_group_used(&shint->item);
295 if (used + shint->pinned <
296 div_factor(shint->key.offset, factor)) {
297 return shint;
298 }
299 }
300 }
301 if (hint && (hint->data == data ||
302 hint->data == BTRFS_BLOCK_GROUP_MIXED)) {
303 used = btrfs_block_group_used(&hint->item);
304 if (used + hint->pinned <
305 div_factor(hint->key.offset, factor)) {
306 return hint;
307 }
308 last = hint->key.objectid + hint->key.offset;
309 hint_last = last;
310 } else {
311 if (hint)
312 hint_last = max(hint->key.objectid, search_start);
313 else
314 hint_last = search_start;
315
316 last = hint_last;
317 }
318 again:
319 while(1) {
320 ret = find_first_extent_bit(block_group_cache, last,
321 &start, &end, bit);
322 if (ret)
323 break;
324
325 ret = get_state_private(block_group_cache, start, &ptr);
326 if (ret)
327 break;
328
329 cache = (struct btrfs_block_group_cache *)(unsigned long)ptr;
330 last = cache->key.objectid + cache->key.offset;
331 used = btrfs_block_group_used(&cache->item);
332
333 if (full_search)
334 free_check = cache->key.offset;
335 else
336 free_check = div_factor(cache->key.offset, factor);
337 if (used + cache->pinned < free_check) {
338 found_group = cache;
339 goto found;
340 }
341 cond_resched();
342 }
343 if (!full_search) {
344 last = search_start;
345 full_search = 1;
346 goto again;
347 }
348 if (!data_swap) {
349 data_swap = 1;
350 bit = BLOCK_GROUP_DATA | BLOCK_GROUP_METADATA;
351 last = search_start;
352 goto again;
353 }
354 found:
355 return found_group;
356 }
357
358 static u64 hash_extent_ref(u64 root_objectid, u64 ref_generation,
359 u64 owner, u64 owner_offset)
360 {
361 u32 high_crc = ~(u32)0;
362 u32 low_crc = ~(u32)0;
363 __le64 lenum;
364
365 lenum = cpu_to_le64(root_objectid);
366 high_crc = crc32c(high_crc, &lenum, sizeof(lenum));
367 lenum = cpu_to_le64(ref_generation);
368 low_crc = crc32c(low_crc, &lenum, sizeof(lenum));
369
370 #if 0
371 lenum = cpu_to_le64(owner);
372 low_crc = crc32c(low_crc, &lenum, sizeof(lenum));
373 lenum = cpu_to_le64(owner_offset);
374 low_crc = crc32c(low_crc, &lenum, sizeof(lenum));
375 #endif
376 return ((u64)high_crc << 32) | (u64)low_crc;
377 }
378
379 static int match_extent_ref(struct extent_buffer *leaf,
380 struct btrfs_extent_ref *disk_ref,
381 struct btrfs_extent_ref *cpu_ref)
382 {
383 int ret;
384 int len;
385
386 if (cpu_ref->objectid)
387 len = sizeof(*cpu_ref);
388 else
389 len = 2 * sizeof(u64);
390 ret = memcmp_extent_buffer(leaf, cpu_ref, (unsigned long)disk_ref,
391 len);
392 return ret == 0;
393 }
394
395 static int lookup_extent_backref(struct btrfs_trans_handle *trans,
396 struct btrfs_root *root,
397 struct btrfs_path *path, u64 bytenr,
398 u64 root_objectid, u64 ref_generation,
399 u64 owner, u64 owner_offset, int del)
400 {
401 u64 hash;
402 struct btrfs_key key;
403 struct btrfs_key found_key;
404 struct btrfs_extent_ref ref;
405 struct extent_buffer *leaf;
406 struct btrfs_extent_ref *disk_ref;
407 int ret;
408 int ret2;
409
410 btrfs_set_stack_ref_root(&ref, root_objectid);
411 btrfs_set_stack_ref_generation(&ref, ref_generation);
412 btrfs_set_stack_ref_objectid(&ref, owner);
413 btrfs_set_stack_ref_offset(&ref, owner_offset);
414
415 hash = hash_extent_ref(root_objectid, ref_generation, owner,
416 owner_offset);
417 key.offset = hash;
418 key.objectid = bytenr;
419 key.type = BTRFS_EXTENT_REF_KEY;
420
421 while (1) {
422 ret = btrfs_search_slot(trans, root, &key, path,
423 del ? -1 : 0, del);
424 if (ret < 0)
425 goto out;
426 leaf = path->nodes[0];
427 if (ret != 0) {
428 u32 nritems = btrfs_header_nritems(leaf);
429 if (path->slots[0] >= nritems) {
430 ret2 = btrfs_next_leaf(root, path);
431 if (ret2)
432 goto out;
433 leaf = path->nodes[0];
434 }
435 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
436 if (found_key.objectid != bytenr ||
437 found_key.type != BTRFS_EXTENT_REF_KEY)
438 goto out;
439 key.offset = found_key.offset;
440 if (del) {
441 btrfs_release_path(root, path);
442 continue;
443 }
444 }
445 disk_ref = btrfs_item_ptr(path->nodes[0],
446 path->slots[0],
447 struct btrfs_extent_ref);
448 if (match_extent_ref(path->nodes[0], disk_ref, &ref)) {
449 ret = 0;
450 goto out;
451 }
452 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
453 key.offset = found_key.offset + 1;
454 btrfs_release_path(root, path);
455 }
456 out:
457 return ret;
458 }
459
460 /*
461 * Back reference rules. Back refs have three main goals:
462 *
463 * 1) differentiate between all holders of references to an extent so that
464 * when a reference is dropped we can make sure it was a valid reference
465 * before freeing the extent.
466 *
467 * 2) Provide enough information to quickly find the holders of an extent
468 * if we notice a given block is corrupted or bad.
469 *
470 * 3) Make it easy to migrate blocks for FS shrinking or storage pool
471 * maintenance. This is actually the same as #2, but with a slightly
472 * different use case.
473 *
474 * File extents can be referenced by:
475 *
476 * - multiple snapshots, subvolumes, or different generations in one subvol
477 * - different files inside a single subvolume (in theory, not implemented yet)
478 * - different offsets inside a file (bookend extents in file.c)
479 *
480 * The extent ref structure has fields for:
481 *
482 * - Objectid of the subvolume root
483 * - Generation number of the tree holding the reference
484 * - objectid of the file holding the reference
485 * - offset in the file corresponding to the key holding the reference
486 *
487 * When a file extent is allocated the fields are filled in:
488 * (root_key.objectid, trans->transid, inode objectid, offset in file)
489 *
490 * When a leaf is cow'd new references are added for every file extent found
491 * in the leaf. It looks the same as the create case, but trans->transid
492 * will be different when the block is cow'd.
493 *
494 * (root_key.objectid, trans->transid, inode objectid, offset in file)
495 *
496 * When a file extent is removed either during snapshot deletion or file
497 * truncation, the corresponding back reference is found
498 * by searching for:
499 *
500 * (btrfs_header_owner(leaf), btrfs_header_generation(leaf),
501 * inode objectid, offset in file)
502 *
503 * Btree extents can be referenced by:
504 *
505 * - Different subvolumes
506 * - Different generations of the same subvolume
507 *
508 * Storing sufficient information for a full reverse mapping of a btree
509 * block would require storing the lowest key of the block in the backref,
510 * and it would require updating that lowest key either before write out or
511 * every time it changed. Instead, the objectid of the lowest key is stored
512 * along with the level of the tree block. This provides a hint
513 * about where in the btree the block can be found. Searches through the
514 * btree only need to look for a pointer to that block, so they stop one
515 * level higher than the level recorded in the backref.
516 *
517 * Some btrees do not do reference counting on their extents. These
518 * include the extent tree and the tree of tree roots. Backrefs for these
519 * trees always have a generation of zero.
520 *
521 * When a tree block is created, back references are inserted:
522 *
523 * (root->root_key.objectid, trans->transid or zero, level, lowest_key_objectid)
524 *
525 * When a tree block is cow'd in a reference counted root,
526 * new back references are added for all the blocks it points to.
527 * These are of the form (trans->transid will have increased since creation):
528 *
529 * (root->root_key.objectid, trans->transid, level, lowest_key_objectid)
530 *
531 * Because the lowest_key_objectid and the level are just hints
532 * they are not used when backrefs are deleted. When a backref is deleted:
533 *
534 * if backref was for a tree root:
535 * root_objectid = root->root_key.objectid
536 * else
537 * root_objectid = btrfs_header_owner(parent)
538 *
539 * (root_objectid, btrfs_header_generation(parent) or zero, 0, 0)
540 *
541 * Back Reference Key hashing:
542 *
543 * Back references have four fields, each 64 bits long. Unfortunately,
544 * This is hashed into a single 64 bit number and placed into the key offset.
545 * The key objectid corresponds to the first byte in the extent, and the
546 * key type is set to BTRFS_EXTENT_REF_KEY
547 */
548 int btrfs_insert_extent_backref(struct btrfs_trans_handle *trans,
549 struct btrfs_root *root,
550 struct btrfs_path *path, u64 bytenr,
551 u64 root_objectid, u64 ref_generation,
552 u64 owner, u64 owner_offset)
553 {
554 u64 hash;
555 struct btrfs_key key;
556 struct btrfs_extent_ref ref;
557 struct btrfs_extent_ref *disk_ref;
558 int ret;
559
560 btrfs_set_stack_ref_root(&ref, root_objectid);
561 btrfs_set_stack_ref_generation(&ref, ref_generation);
562 btrfs_set_stack_ref_objectid(&ref, owner);
563 btrfs_set_stack_ref_offset(&ref, owner_offset);
564
565 hash = hash_extent_ref(root_objectid, ref_generation, owner,
566 owner_offset);
567 key.offset = hash;
568 key.objectid = bytenr;
569 key.type = BTRFS_EXTENT_REF_KEY;
570
571 ret = btrfs_insert_empty_item(trans, root, path, &key, sizeof(ref));
572 while (ret == -EEXIST) {
573 disk_ref = btrfs_item_ptr(path->nodes[0], path->slots[0],
574 struct btrfs_extent_ref);
575 if (match_extent_ref(path->nodes[0], disk_ref, &ref))
576 goto out;
577 key.offset++;
578 btrfs_release_path(root, path);
579 ret = btrfs_insert_empty_item(trans, root, path, &key,
580 sizeof(ref));
581 }
582 if (ret)
583 goto out;
584 disk_ref = btrfs_item_ptr(path->nodes[0], path->slots[0],
585 struct btrfs_extent_ref);
586 write_extent_buffer(path->nodes[0], &ref, (unsigned long)disk_ref,
587 sizeof(ref));
588 btrfs_mark_buffer_dirty(path->nodes[0]);
589 out:
590 btrfs_release_path(root, path);
591 return ret;
592 }
593
594 int btrfs_inc_extent_ref(struct btrfs_trans_handle *trans,
595 struct btrfs_root *root,
596 u64 bytenr, u64 num_bytes,
597 u64 root_objectid, u64 ref_generation,
598 u64 owner, u64 owner_offset)
599 {
600 struct btrfs_path *path;
601 int ret;
602 struct btrfs_key key;
603 struct extent_buffer *l;
604 struct btrfs_extent_item *item;
605 u32 refs;
606
607 WARN_ON(num_bytes < root->sectorsize);
608 path = btrfs_alloc_path();
609 if (!path)
610 return -ENOMEM;
611
612 key.objectid = bytenr;
613 btrfs_set_key_type(&key, BTRFS_EXTENT_ITEM_KEY);
614 key.offset = num_bytes;
615 ret = btrfs_search_slot(trans, root->fs_info->extent_root, &key, path,
616 0, 1);
617 if (ret < 0)
618 return ret;
619 if (ret != 0) {
620 BUG();
621 }
622 BUG_ON(ret != 0);
623 l = path->nodes[0];
624 item = btrfs_item_ptr(l, path->slots[0], struct btrfs_extent_item);
625 refs = btrfs_extent_refs(l, item);
626 btrfs_set_extent_refs(l, item, refs + 1);
627 btrfs_mark_buffer_dirty(path->nodes[0]);
628
629 btrfs_release_path(root->fs_info->extent_root, path);
630
631 ret = btrfs_insert_extent_backref(trans, root->fs_info->extent_root,
632 path, bytenr, root_objectid,
633 ref_generation, owner, owner_offset);
634 BUG_ON(ret);
635 finish_current_insert(trans, root->fs_info->extent_root);
636 del_pending_extents(trans, root->fs_info->extent_root);
637
638 btrfs_free_path(path);
639 return 0;
640 }
641
642 int btrfs_extent_post_op(struct btrfs_trans_handle *trans,
643 struct btrfs_root *root)
644 {
645 finish_current_insert(trans, root->fs_info->extent_root);
646 del_pending_extents(trans, root->fs_info->extent_root);
647 return 0;
648 }
649
650 static int lookup_extent_ref(struct btrfs_trans_handle *trans,
651 struct btrfs_root *root, u64 bytenr,
652 u64 num_bytes, u32 *refs)
653 {
654 struct btrfs_path *path;
655 int ret;
656 struct btrfs_key key;
657 struct extent_buffer *l;
658 struct btrfs_extent_item *item;
659
660 WARN_ON(num_bytes < root->sectorsize);
661 path = btrfs_alloc_path();
662 key.objectid = bytenr;
663 key.offset = num_bytes;
664 btrfs_set_key_type(&key, BTRFS_EXTENT_ITEM_KEY);
665 ret = btrfs_search_slot(trans, root->fs_info->extent_root, &key, path,
666 0, 0);
667 if (ret < 0)
668 goto out;
669 if (ret != 0) {
670 btrfs_print_leaf(root, path->nodes[0]);
671 printk("failed to find block number %Lu\n", bytenr);
672 BUG();
673 }
674 l = path->nodes[0];
675 item = btrfs_item_ptr(l, path->slots[0], struct btrfs_extent_item);
676 *refs = btrfs_extent_refs(l, item);
677 out:
678 btrfs_free_path(path);
679 return 0;
680 }
681
682 u32 btrfs_count_snapshots_in_path(struct btrfs_root *root,
683 struct btrfs_path *count_path,
684 u64 first_extent)
685 {
686 struct btrfs_root *extent_root = root->fs_info->extent_root;
687 struct btrfs_path *path;
688 u64 bytenr;
689 u64 found_objectid;
690 u64 root_objectid = 0;
691 u32 total_count = 0;
692 u32 cur_count;
693 u32 refs;
694 u32 nritems;
695 int ret;
696 struct btrfs_key key;
697 struct btrfs_key found_key;
698 struct extent_buffer *l;
699 struct btrfs_extent_item *item;
700 struct btrfs_extent_ref *ref_item;
701 int level = -1;
702
703 path = btrfs_alloc_path();
704 again:
705 if (level == -1)
706 bytenr = first_extent;
707 else
708 bytenr = count_path->nodes[level]->start;
709
710 cur_count = 0;
711 key.objectid = bytenr;
712 key.offset = 0;
713
714 btrfs_set_key_type(&key, BTRFS_EXTENT_ITEM_KEY);
715 ret = btrfs_search_slot(NULL, extent_root, &key, path, 0, 0);
716 if (ret < 0)
717 goto out;
718 BUG_ON(ret == 0);
719
720 l = path->nodes[0];
721 btrfs_item_key_to_cpu(l, &found_key, path->slots[0]);
722
723 if (found_key.objectid != bytenr ||
724 found_key.type != BTRFS_EXTENT_ITEM_KEY) {
725 goto out;
726 }
727
728 item = btrfs_item_ptr(l, path->slots[0], struct btrfs_extent_item);
729 refs = btrfs_extent_refs(l, item);
730 while (1) {
731 nritems = btrfs_header_nritems(l);
732 if (path->slots[0] >= nritems) {
733 ret = btrfs_next_leaf(extent_root, path);
734 if (ret == 0)
735 continue;
736 break;
737 }
738 btrfs_item_key_to_cpu(l, &found_key, path->slots[0]);
739 if (found_key.objectid != bytenr)
740 break;
741 if (found_key.type != BTRFS_EXTENT_REF_KEY) {
742 path->slots[0]++;
743 continue;
744 }
745
746 cur_count++;
747 ref_item = btrfs_item_ptr(l, path->slots[0],
748 struct btrfs_extent_ref);
749 found_objectid = btrfs_ref_root(l, ref_item);
750
751 if (found_objectid != root_objectid)
752 total_count++;
753
754 if (total_count > 1)
755 goto out;
756
757 if (root_objectid == 0)
758 root_objectid = found_objectid;
759
760 path->slots[0]++;
761 }
762 if (cur_count == 0) {
763 total_count = 0;
764 goto out;
765 }
766 if (total_count > 1)
767 goto out;
768 if (level >= 0 && root->node == count_path->nodes[level])
769 goto out;
770 level++;
771 btrfs_release_path(root, path);
772 goto again;
773
774 out:
775 btrfs_free_path(path);
776 return total_count;
777
778 }
779
780 int btrfs_inc_root_ref(struct btrfs_trans_handle *trans,
781 struct btrfs_root *root, u64 owner_objectid)
782 {
783 u64 generation;
784 u64 key_objectid;
785 u64 level;
786 u32 nritems;
787 struct btrfs_disk_key disk_key;
788
789 level = btrfs_header_level(root->node);
790 generation = trans->transid;
791 nritems = btrfs_header_nritems(root->node);
792 if (nritems > 0) {
793 if (level == 0)
794 btrfs_item_key(root->node, &disk_key, 0);
795 else
796 btrfs_node_key(root->node, &disk_key, 0);
797 key_objectid = btrfs_disk_key_objectid(&disk_key);
798 } else {
799 key_objectid = 0;
800 }
801 return btrfs_inc_extent_ref(trans, root, root->node->start,
802 root->node->len, owner_objectid,
803 generation, level, key_objectid);
804 }
805
806 int btrfs_inc_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root,
807 struct extent_buffer *buf)
808 {
809 u64 bytenr;
810 u32 nritems;
811 struct btrfs_key key;
812 struct btrfs_file_extent_item *fi;
813 int i;
814 int level;
815 int ret;
816 int faili;
817
818 if (!root->ref_cows)
819 return 0;
820
821 level = btrfs_header_level(buf);
822 nritems = btrfs_header_nritems(buf);
823 for (i = 0; i < nritems; i++) {
824 if (level == 0) {
825 u64 disk_bytenr;
826 btrfs_item_key_to_cpu(buf, &key, i);
827 if (btrfs_key_type(&key) != BTRFS_EXTENT_DATA_KEY)
828 continue;
829 fi = btrfs_item_ptr(buf, i,
830 struct btrfs_file_extent_item);
831 if (btrfs_file_extent_type(buf, fi) ==
832 BTRFS_FILE_EXTENT_INLINE)
833 continue;
834 disk_bytenr = btrfs_file_extent_disk_bytenr(buf, fi);
835 if (disk_bytenr == 0)
836 continue;
837 ret = btrfs_inc_extent_ref(trans, root, disk_bytenr,
838 btrfs_file_extent_disk_num_bytes(buf, fi),
839 root->root_key.objectid, trans->transid,
840 key.objectid, key.offset);
841 if (ret) {
842 faili = i;
843 goto fail;
844 }
845 } else {
846 bytenr = btrfs_node_blockptr(buf, i);
847 btrfs_node_key_to_cpu(buf, &key, i);
848 ret = btrfs_inc_extent_ref(trans, root, bytenr,
849 btrfs_level_size(root, level - 1),
850 root->root_key.objectid,
851 trans->transid,
852 level - 1, key.objectid);
853 if (ret) {
854 faili = i;
855 goto fail;
856 }
857 }
858 }
859 return 0;
860 fail:
861 WARN_ON(1);
862 #if 0
863 for (i =0; i < faili; i++) {
864 if (level == 0) {
865 u64 disk_bytenr;
866 btrfs_item_key_to_cpu(buf, &key, i);
867 if (btrfs_key_type(&key) != BTRFS_EXTENT_DATA_KEY)
868 continue;
869 fi = btrfs_item_ptr(buf, i,
870 struct btrfs_file_extent_item);
871 if (btrfs_file_extent_type(buf, fi) ==
872 BTRFS_FILE_EXTENT_INLINE)
873 continue;
874 disk_bytenr = btrfs_file_extent_disk_bytenr(buf, fi);
875 if (disk_bytenr == 0)
876 continue;
877 err = btrfs_free_extent(trans, root, disk_bytenr,
878 btrfs_file_extent_disk_num_bytes(buf,
879 fi), 0);
880 BUG_ON(err);
881 } else {
882 bytenr = btrfs_node_blockptr(buf, i);
883 err = btrfs_free_extent(trans, root, bytenr,
884 btrfs_level_size(root, level - 1), 0);
885 BUG_ON(err);
886 }
887 }
888 #endif
889 return ret;
890 }
891
892 static int write_one_cache_group(struct btrfs_trans_handle *trans,
893 struct btrfs_root *root,
894 struct btrfs_path *path,
895 struct btrfs_block_group_cache *cache)
896 {
897 int ret;
898 int pending_ret;
899 struct btrfs_root *extent_root = root->fs_info->extent_root;
900 unsigned long bi;
901 struct extent_buffer *leaf;
902
903 ret = btrfs_search_slot(trans, extent_root, &cache->key, path, 0, 1);
904 if (ret < 0)
905 goto fail;
906 BUG_ON(ret);
907
908 leaf = path->nodes[0];
909 bi = btrfs_item_ptr_offset(leaf, path->slots[0]);
910 write_extent_buffer(leaf, &cache->item, bi, sizeof(cache->item));
911 btrfs_mark_buffer_dirty(leaf);
912 btrfs_release_path(extent_root, path);
913 fail:
914 finish_current_insert(trans, extent_root);
915 pending_ret = del_pending_extents(trans, extent_root);
916 if (ret)
917 return ret;
918 if (pending_ret)
919 return pending_ret;
920 return 0;
921
922 }
923
924 int btrfs_write_dirty_block_groups(struct btrfs_trans_handle *trans,
925 struct btrfs_root *root)
926 {
927 struct extent_map_tree *block_group_cache;
928 struct btrfs_block_group_cache *cache;
929 int ret;
930 int err = 0;
931 int werr = 0;
932 struct btrfs_path *path;
933 u64 last = 0;
934 u64 start;
935 u64 end;
936 u64 ptr;
937
938 block_group_cache = &root->fs_info->block_group_cache;
939 path = btrfs_alloc_path();
940 if (!path)
941 return -ENOMEM;
942
943 while(1) {
944 ret = find_first_extent_bit(block_group_cache, last,
945 &start, &end, BLOCK_GROUP_DIRTY);
946 if (ret)
947 break;
948
949 last = end + 1;
950 ret = get_state_private(block_group_cache, start, &ptr);
951 if (ret)
952 break;
953
954 cache = (struct btrfs_block_group_cache *)(unsigned long)ptr;
955 err = write_one_cache_group(trans, root,
956 path, cache);
957 /*
958 * if we fail to write the cache group, we want
959 * to keep it marked dirty in hopes that a later
960 * write will work
961 */
962 if (err) {
963 werr = err;
964 continue;
965 }
966 clear_extent_bits(block_group_cache, start, end,
967 BLOCK_GROUP_DIRTY, GFP_NOFS);
968 }
969 btrfs_free_path(path);
970 return werr;
971 }
972
973 static int update_block_group(struct btrfs_trans_handle *trans,
974 struct btrfs_root *root,
975 u64 bytenr, u64 num_bytes, int alloc,
976 int mark_free, int data)
977 {
978 struct btrfs_block_group_cache *cache;
979 struct btrfs_fs_info *info = root->fs_info;
980 u64 total = num_bytes;
981 u64 old_val;
982 u64 byte_in_group;
983 u64 start;
984 u64 end;
985
986 while(total) {
987 cache = btrfs_lookup_block_group(info, bytenr);
988 if (!cache) {
989 return -1;
990 }
991 byte_in_group = bytenr - cache->key.objectid;
992 WARN_ON(byte_in_group > cache->key.offset);
993 start = cache->key.objectid;
994 end = start + cache->key.offset - 1;
995 set_extent_bits(&info->block_group_cache, start, end,
996 BLOCK_GROUP_DIRTY, GFP_NOFS);
997
998 old_val = btrfs_block_group_used(&cache->item);
999 num_bytes = min(total, cache->key.offset - byte_in_group);
1000 if (alloc) {
1001 if (cache->data != data &&
1002 old_val < (cache->key.offset >> 1)) {
1003 int bit_to_clear;
1004 int bit_to_set;
1005 cache->data = data;
1006 if (data) {
1007 bit_to_clear = BLOCK_GROUP_METADATA;
1008 bit_to_set = BLOCK_GROUP_DATA;
1009 cache->item.flags &=
1010 ~BTRFS_BLOCK_GROUP_MIXED;
1011 cache->item.flags |=
1012 BTRFS_BLOCK_GROUP_DATA;
1013 } else {
1014 bit_to_clear = BLOCK_GROUP_DATA;
1015 bit_to_set = BLOCK_GROUP_METADATA;
1016 cache->item.flags &=
1017 ~BTRFS_BLOCK_GROUP_MIXED;
1018 cache->item.flags &=
1019 ~BTRFS_BLOCK_GROUP_DATA;
1020 }
1021 clear_extent_bits(&info->block_group_cache,
1022 start, end, bit_to_clear,
1023 GFP_NOFS);
1024 set_extent_bits(&info->block_group_cache,
1025 start, end, bit_to_set,
1026 GFP_NOFS);
1027 } else if (cache->data != data &&
1028 cache->data != BTRFS_BLOCK_GROUP_MIXED) {
1029 cache->data = BTRFS_BLOCK_GROUP_MIXED;
1030 set_extent_bits(&info->block_group_cache,
1031 start, end,
1032 BLOCK_GROUP_DATA |
1033 BLOCK_GROUP_METADATA,
1034 GFP_NOFS);
1035 }
1036 old_val += num_bytes;
1037 } else {
1038 old_val -= num_bytes;
1039 if (mark_free) {
1040 set_extent_dirty(&info->free_space_cache,
1041 bytenr, bytenr + num_bytes - 1,
1042 GFP_NOFS);
1043 }
1044 }
1045 btrfs_set_block_group_used(&cache->item, old_val);
1046 total -= num_bytes;
1047 bytenr += num_bytes;
1048 }
1049 return 0;
1050 }
1051 static int update_pinned_extents(struct btrfs_root *root,
1052 u64 bytenr, u64 num, int pin)
1053 {
1054 u64 len;
1055 struct btrfs_block_group_cache *cache;
1056 struct btrfs_fs_info *fs_info = root->fs_info;
1057
1058 if (pin) {
1059 set_extent_dirty(&fs_info->pinned_extents,
1060 bytenr, bytenr + num - 1, GFP_NOFS);
1061 } else {
1062 clear_extent_dirty(&fs_info->pinned_extents,
1063 bytenr, bytenr + num - 1, GFP_NOFS);
1064 }
1065 while (num > 0) {
1066 cache = btrfs_lookup_block_group(fs_info, bytenr);
1067 WARN_ON(!cache);
1068 len = min(num, cache->key.offset -
1069 (bytenr - cache->key.objectid));
1070 if (pin) {
1071 cache->pinned += len;
1072 fs_info->total_pinned += len;
1073 } else {
1074 cache->pinned -= len;
1075 fs_info->total_pinned -= len;
1076 }
1077 bytenr += len;
1078 num -= len;
1079 }
1080 return 0;
1081 }
1082
1083 int btrfs_copy_pinned(struct btrfs_root *root, struct extent_map_tree *copy)
1084 {
1085 u64 last = 0;
1086 u64 start;
1087 u64 end;
1088 struct extent_map_tree *pinned_extents = &root->fs_info->pinned_extents;
1089 int ret;
1090
1091 while(1) {
1092 ret = find_first_extent_bit(pinned_extents, last,
1093 &start, &end, EXTENT_DIRTY);
1094 if (ret)
1095 break;
1096 set_extent_dirty(copy, start, end, GFP_NOFS);
1097 last = end + 1;
1098 }
1099 return 0;
1100 }
1101
1102 int btrfs_finish_extent_commit(struct btrfs_trans_handle *trans,
1103 struct btrfs_root *root,
1104 struct extent_map_tree *unpin)
1105 {
1106 u64 start;
1107 u64 end;
1108 int ret;
1109 struct extent_map_tree *free_space_cache;
1110 free_space_cache = &root->fs_info->free_space_cache;
1111
1112 while(1) {
1113 ret = find_first_extent_bit(unpin, 0, &start, &end,
1114 EXTENT_DIRTY);
1115 if (ret)
1116 break;
1117 update_pinned_extents(root, start, end + 1 - start, 0);
1118 clear_extent_dirty(unpin, start, end, GFP_NOFS);
1119 set_extent_dirty(free_space_cache, start, end, GFP_NOFS);
1120 }
1121 return 0;
1122 }
1123
1124 static int finish_current_insert(struct btrfs_trans_handle *trans, struct
1125 btrfs_root *extent_root)
1126 {
1127 u64 start;
1128 u64 end;
1129 struct btrfs_fs_info *info = extent_root->fs_info;
1130 struct extent_buffer *eb;
1131 struct btrfs_path *path;
1132 struct btrfs_key ins;
1133 struct btrfs_disk_key first;
1134 struct btrfs_extent_item extent_item;
1135 int ret;
1136 int level;
1137 int err = 0;
1138
1139 btrfs_set_stack_extent_refs(&extent_item, 1);
1140 btrfs_set_key_type(&ins, BTRFS_EXTENT_ITEM_KEY);
1141 path = btrfs_alloc_path();
1142
1143 while(1) {
1144 ret = find_first_extent_bit(&info->extent_ins, 0, &start,
1145 &end, EXTENT_LOCKED);
1146 if (ret)
1147 break;
1148
1149 ins.objectid = start;
1150 ins.offset = end + 1 - start;
1151 err = btrfs_insert_item(trans, extent_root, &ins,
1152 &extent_item, sizeof(extent_item));
1153 clear_extent_bits(&info->extent_ins, start, end, EXTENT_LOCKED,
1154 GFP_NOFS);
1155 eb = read_tree_block(extent_root, ins.objectid, ins.offset);
1156 level = btrfs_header_level(eb);
1157 if (level == 0) {
1158 btrfs_item_key(eb, &first, 0);
1159 } else {
1160 btrfs_node_key(eb, &first, 0);
1161 }
1162 err = btrfs_insert_extent_backref(trans, extent_root, path,
1163 start, extent_root->root_key.objectid,
1164 0, level,
1165 btrfs_disk_key_objectid(&first));
1166 BUG_ON(err);
1167 free_extent_buffer(eb);
1168 }
1169 btrfs_free_path(path);
1170 return 0;
1171 }
1172
1173 static int pin_down_bytes(struct btrfs_root *root, u64 bytenr, u32 num_bytes,
1174 int pending)
1175 {
1176 int err = 0;
1177 struct extent_buffer *buf;
1178
1179 if (!pending) {
1180 buf = btrfs_find_tree_block(root, bytenr, num_bytes);
1181 if (buf) {
1182 if (btrfs_buffer_uptodate(buf)) {
1183 u64 transid =
1184 root->fs_info->running_transaction->transid;
1185 if (btrfs_header_generation(buf) == transid) {
1186 free_extent_buffer(buf);
1187 return 1;
1188 }
1189 }
1190 free_extent_buffer(buf);
1191 }
1192 update_pinned_extents(root, bytenr, num_bytes, 1);
1193 } else {
1194 set_extent_bits(&root->fs_info->pending_del,
1195 bytenr, bytenr + num_bytes - 1,
1196 EXTENT_LOCKED, GFP_NOFS);
1197 }
1198 BUG_ON(err < 0);
1199 return 0;
1200 }
1201
1202 /*
1203 * remove an extent from the root, returns 0 on success
1204 */
1205 static int __free_extent(struct btrfs_trans_handle *trans, struct btrfs_root
1206 *root, u64 bytenr, u64 num_bytes,
1207 u64 root_objectid, u64 ref_generation,
1208 u64 owner_objectid, u64 owner_offset, int pin,
1209 int mark_free)
1210 {
1211 struct btrfs_path *path;
1212 struct btrfs_key key;
1213 struct btrfs_fs_info *info = root->fs_info;
1214 struct btrfs_root *extent_root = info->extent_root;
1215 struct extent_buffer *leaf;
1216 int ret;
1217 struct btrfs_extent_item *ei;
1218 u32 refs;
1219
1220 key.objectid = bytenr;
1221 btrfs_set_key_type(&key, BTRFS_EXTENT_ITEM_KEY);
1222 key.offset = num_bytes;
1223
1224 path = btrfs_alloc_path();
1225 if (!path)
1226 return -ENOMEM;
1227
1228 ret = lookup_extent_backref(trans, extent_root, path,
1229 bytenr, root_objectid,
1230 ref_generation,
1231 owner_objectid, owner_offset, 1);
1232 if (ret == 0) {
1233 ret = btrfs_del_item(trans, extent_root, path);
1234 } else {
1235 btrfs_print_leaf(extent_root, path->nodes[0]);
1236 WARN_ON(1);
1237 printk("Unable to find ref byte nr %Lu root %Lu "
1238 " gen %Lu owner %Lu offset %Lu\n", bytenr,
1239 root_objectid, ref_generation, owner_objectid,
1240 owner_offset);
1241 }
1242 btrfs_release_path(extent_root, path);
1243 ret = btrfs_search_slot(trans, extent_root, &key, path, -1, 1);
1244 if (ret < 0)
1245 return ret;
1246 BUG_ON(ret);
1247
1248 leaf = path->nodes[0];
1249 ei = btrfs_item_ptr(leaf, path->slots[0],
1250 struct btrfs_extent_item);
1251 refs = btrfs_extent_refs(leaf, ei);
1252 BUG_ON(refs == 0);
1253 refs -= 1;
1254 btrfs_set_extent_refs(leaf, ei, refs);
1255 btrfs_mark_buffer_dirty(leaf);
1256
1257 if (refs == 0) {
1258 u64 super_used;
1259 u64 root_used;
1260
1261 if (pin) {
1262 ret = pin_down_bytes(root, bytenr, num_bytes, 0);
1263 if (ret > 0)
1264 mark_free = 1;
1265 BUG_ON(ret < 0);
1266 }
1267
1268 /* block accounting for super block */
1269 super_used = btrfs_super_bytes_used(&info->super_copy);
1270 btrfs_set_super_bytes_used(&info->super_copy,
1271 super_used - num_bytes);
1272
1273 /* block accounting for root item */
1274 root_used = btrfs_root_used(&root->root_item);
1275 btrfs_set_root_used(&root->root_item,
1276 root_used - num_bytes);
1277
1278 ret = btrfs_del_item(trans, extent_root, path);
1279 if (ret) {
1280 return ret;
1281 }
1282 ret = update_block_group(trans, root, bytenr, num_bytes, 0,
1283 mark_free, 0);
1284 BUG_ON(ret);
1285 }
1286 btrfs_free_path(path);
1287 finish_current_insert(trans, extent_root);
1288 return ret;
1289 }
1290
1291 /*
1292 * find all the blocks marked as pending in the radix tree and remove
1293 * them from the extent map
1294 */
1295 static int del_pending_extents(struct btrfs_trans_handle *trans, struct
1296 btrfs_root *extent_root)
1297 {
1298 int ret;
1299 int err = 0;
1300 u64 start;
1301 u64 end;
1302 struct extent_map_tree *pending_del;
1303 struct extent_map_tree *pinned_extents;
1304
1305 pending_del = &extent_root->fs_info->pending_del;
1306 pinned_extents = &extent_root->fs_info->pinned_extents;
1307
1308 while(1) {
1309 ret = find_first_extent_bit(pending_del, 0, &start, &end,
1310 EXTENT_LOCKED);
1311 if (ret)
1312 break;
1313 update_pinned_extents(extent_root, start, end + 1 - start, 1);
1314 clear_extent_bits(pending_del, start, end, EXTENT_LOCKED,
1315 GFP_NOFS);
1316 ret = __free_extent(trans, extent_root,
1317 start, end + 1 - start,
1318 extent_root->root_key.objectid,
1319 0, 0, 0, 0, 0);
1320 if (ret)
1321 err = ret;
1322 }
1323 return err;
1324 }
1325
1326 /*
1327 * remove an extent from the root, returns 0 on success
1328 */
1329 int btrfs_free_extent(struct btrfs_trans_handle *trans, struct btrfs_root
1330 *root, u64 bytenr, u64 num_bytes,
1331 u64 root_objectid, u64 ref_generation,
1332 u64 owner_objectid, u64 owner_offset, int pin)
1333 {
1334 struct btrfs_root *extent_root = root->fs_info->extent_root;
1335 int pending_ret;
1336 int ret;
1337
1338 WARN_ON(num_bytes < root->sectorsize);
1339 if (!root->ref_cows)
1340 ref_generation = 0;
1341
1342 if (root == extent_root) {
1343 pin_down_bytes(root, bytenr, num_bytes, 1);
1344 return 0;
1345 }
1346 ret = __free_extent(trans, root, bytenr, num_bytes, root_objectid,
1347 ref_generation, owner_objectid, owner_offset,
1348 pin, pin == 0);
1349 pending_ret = del_pending_extents(trans, root->fs_info->extent_root);
1350 return ret ? ret : pending_ret;
1351 }
1352
1353 static u64 stripe_align(struct btrfs_root *root, u64 val)
1354 {
1355 u64 mask = ((u64)root->stripesize - 1);
1356 u64 ret = (val + mask) & ~mask;
1357 return ret;
1358 }
1359
1360 /*
1361 * walks the btree of allocated extents and find a hole of a given size.
1362 * The key ins is changed to record the hole:
1363 * ins->objectid == block start
1364 * ins->flags = BTRFS_EXTENT_ITEM_KEY
1365 * ins->offset == number of blocks
1366 * Any available blocks before search_start are skipped.
1367 */
1368 static int find_free_extent(struct btrfs_trans_handle *trans, struct btrfs_root
1369 *orig_root, u64 num_bytes, u64 empty_size,
1370 u64 search_start, u64 search_end, u64 hint_byte,
1371 struct btrfs_key *ins, u64 exclude_start,
1372 u64 exclude_nr, int data)
1373 {
1374 struct btrfs_path *path;
1375 struct btrfs_key key;
1376 u64 hole_size = 0;
1377 u64 aligned;
1378 int ret;
1379 int slot = 0;
1380 u64 last_byte = 0;
1381 u64 orig_search_start = search_start;
1382 int start_found;
1383 struct extent_buffer *l;
1384 struct btrfs_root * root = orig_root->fs_info->extent_root;
1385 struct btrfs_fs_info *info = root->fs_info;
1386 u64 total_needed = num_bytes;
1387 int level;
1388 struct btrfs_block_group_cache *block_group;
1389 int full_scan = 0;
1390 int wrapped = 0;
1391 u64 cached_start;
1392
1393 WARN_ON(num_bytes < root->sectorsize);
1394 btrfs_set_key_type(ins, BTRFS_EXTENT_ITEM_KEY);
1395
1396 level = btrfs_header_level(root->node);
1397
1398 if (num_bytes >= 32 * 1024 * 1024 && hint_byte) {
1399 data = BTRFS_BLOCK_GROUP_MIXED;
1400 }
1401
1402 if (search_end == (u64)-1)
1403 search_end = btrfs_super_total_bytes(&info->super_copy);
1404 if (hint_byte) {
1405 block_group = btrfs_lookup_block_group(info, hint_byte);
1406 if (!block_group)
1407 hint_byte = search_start;
1408 block_group = btrfs_find_block_group(root, block_group,
1409 hint_byte, data, 1);
1410 } else {
1411 block_group = btrfs_find_block_group(root,
1412 trans->block_group,
1413 search_start, data, 1);
1414 }
1415
1416 total_needed += empty_size;
1417 path = btrfs_alloc_path();
1418 check_failed:
1419 if (!block_group) {
1420 block_group = btrfs_lookup_block_group(info, search_start);
1421 if (!block_group)
1422 block_group = btrfs_lookup_block_group(info,
1423 orig_search_start);
1424 }
1425 search_start = find_search_start(root, &block_group, search_start,
1426 total_needed, data, full_scan);
1427 search_start = stripe_align(root, search_start);
1428 cached_start = search_start;
1429 btrfs_init_path(path);
1430 ins->objectid = search_start;
1431 ins->offset = 0;
1432 start_found = 0;
1433 path->reada = 2;
1434
1435 ret = btrfs_search_slot(trans, root, ins, path, 0, 0);
1436 if (ret < 0)
1437 goto error;
1438
1439 if (path->slots[0] > 0) {
1440 path->slots[0]--;
1441 }
1442
1443 l = path->nodes[0];
1444 btrfs_item_key_to_cpu(l, &key, path->slots[0]);
1445
1446 /*
1447 * walk backwards to find the first extent item key
1448 */
1449 while(btrfs_key_type(&key) != BTRFS_EXTENT_ITEM_KEY) {
1450 if (path->slots[0] == 0) {
1451 ret = btrfs_prev_leaf(root, path);
1452 if (ret != 0) {
1453 ret = btrfs_search_slot(trans, root, ins,
1454 path, 0, 0);
1455 if (ret < 0)
1456 goto error;
1457 if (path->slots[0] > 0)
1458 path->slots[0]--;
1459 break;
1460 }
1461 } else {
1462 path->slots[0]--;
1463 }
1464 l = path->nodes[0];
1465 btrfs_item_key_to_cpu(l, &key, path->slots[0]);
1466 }
1467 while (1) {
1468 l = path->nodes[0];
1469 slot = path->slots[0];
1470 if (slot >= btrfs_header_nritems(l)) {
1471 ret = btrfs_next_leaf(root, path);
1472 if (ret == 0)
1473 continue;
1474 if (ret < 0)
1475 goto error;
1476
1477 search_start = max(search_start,
1478 block_group->key.objectid);
1479 if (!start_found) {
1480 aligned = stripe_align(root, search_start);
1481 ins->objectid = aligned;
1482 if (aligned >= search_end) {
1483 ret = -ENOSPC;
1484 goto error;
1485 }
1486 ins->offset = search_end - aligned;
1487 start_found = 1;
1488 goto check_pending;
1489 }
1490 ins->objectid = stripe_align(root,
1491 last_byte > search_start ?
1492 last_byte : search_start);
1493 if (search_end <= ins->objectid) {
1494 ret = -ENOSPC;
1495 goto error;
1496 }
1497 ins->offset = search_end - ins->objectid;
1498 BUG_ON(ins->objectid >= search_end);
1499 goto check_pending;
1500 }
1501 btrfs_item_key_to_cpu(l, &key, slot);
1502
1503 if (key.objectid >= search_start && key.objectid > last_byte &&
1504 start_found) {
1505 if (last_byte < search_start)
1506 last_byte = search_start;
1507 aligned = stripe_align(root, last_byte);
1508 hole_size = key.objectid - aligned;
1509 if (key.objectid > aligned && hole_size >= num_bytes) {
1510 ins->objectid = aligned;
1511 ins->offset = hole_size;
1512 goto check_pending;
1513 }
1514 }
1515 if (btrfs_key_type(&key) != BTRFS_EXTENT_ITEM_KEY) {
1516 if (!start_found && btrfs_key_type(&key) ==
1517 BTRFS_BLOCK_GROUP_ITEM_KEY) {
1518 last_byte = key.objectid;
1519 start_found = 1;
1520 }
1521 goto next;
1522 }
1523
1524
1525 start_found = 1;
1526 last_byte = key.objectid + key.offset;
1527
1528 if (!full_scan && data != BTRFS_BLOCK_GROUP_MIXED &&
1529 last_byte >= block_group->key.objectid +
1530 block_group->key.offset) {
1531 btrfs_release_path(root, path);
1532 search_start = block_group->key.objectid +
1533 block_group->key.offset;
1534 goto new_group;
1535 }
1536 next:
1537 path->slots[0]++;
1538 cond_resched();
1539 }
1540 check_pending:
1541 /* we have to make sure we didn't find an extent that has already
1542 * been allocated by the map tree or the original allocation
1543 */
1544 btrfs_release_path(root, path);
1545 BUG_ON(ins->objectid < search_start);
1546
1547 if (ins->objectid + num_bytes >= search_end)
1548 goto enospc;
1549 if (!full_scan && data != BTRFS_BLOCK_GROUP_MIXED &&
1550 ins->objectid + num_bytes > block_group->
1551 key.objectid + block_group->key.offset) {
1552 search_start = block_group->key.objectid +
1553 block_group->key.offset;
1554 goto new_group;
1555 }
1556 if (test_range_bit(&info->extent_ins, ins->objectid,
1557 ins->objectid + num_bytes -1, EXTENT_LOCKED, 0)) {
1558 search_start = ins->objectid + num_bytes;
1559 goto new_group;
1560 }
1561 if (test_range_bit(&info->pinned_extents, ins->objectid,
1562 ins->objectid + num_bytes -1, EXTENT_DIRTY, 0)) {
1563 search_start = ins->objectid + num_bytes;
1564 goto new_group;
1565 }
1566 if (exclude_nr > 0 && (ins->objectid + num_bytes > exclude_start &&
1567 ins->objectid < exclude_start + exclude_nr)) {
1568 search_start = exclude_start + exclude_nr;
1569 goto new_group;
1570 }
1571 if (!data) {
1572 block_group = btrfs_lookup_block_group(info, ins->objectid);
1573 if (block_group)
1574 trans->block_group = block_group;
1575 }
1576 ins->offset = num_bytes;
1577 btrfs_free_path(path);
1578 return 0;
1579
1580 new_group:
1581 if (search_start + num_bytes >= search_end) {
1582 enospc:
1583 search_start = orig_search_start;
1584 if (full_scan) {
1585 ret = -ENOSPC;
1586 goto error;
1587 }
1588 if (wrapped) {
1589 if (!full_scan)
1590 total_needed -= empty_size;
1591 full_scan = 1;
1592 data = BTRFS_BLOCK_GROUP_MIXED;
1593 } else
1594 wrapped = 1;
1595 }
1596 block_group = btrfs_lookup_block_group(info, search_start);
1597 cond_resched();
1598 block_group = btrfs_find_block_group(root, block_group,
1599 search_start, data, 0);
1600 goto check_failed;
1601
1602 error:
1603 btrfs_release_path(root, path);
1604 btrfs_free_path(path);
1605 return ret;
1606 }
1607 /*
1608 * finds a free extent and does all the dirty work required for allocation
1609 * returns the key for the extent through ins, and a tree buffer for
1610 * the first block of the extent through buf.
1611 *
1612 * returns 0 if everything worked, non-zero otherwise.
1613 */
1614 int btrfs_alloc_extent(struct btrfs_trans_handle *trans,
1615 struct btrfs_root *root,
1616 u64 num_bytes, u64 root_objectid, u64 ref_generation,
1617 u64 owner, u64 owner_offset,
1618 u64 empty_size, u64 hint_byte,
1619 u64 search_end, struct btrfs_key *ins, int data)
1620 {
1621 int ret;
1622 int pending_ret;
1623 u64 super_used, root_used;
1624 u64 search_start = 0;
1625 struct btrfs_fs_info *info = root->fs_info;
1626 struct btrfs_root *extent_root = info->extent_root;
1627 struct btrfs_extent_item extent_item;
1628 struct btrfs_path *path;
1629
1630 btrfs_set_stack_extent_refs(&extent_item, 1);
1631
1632 WARN_ON(num_bytes < root->sectorsize);
1633 ret = find_free_extent(trans, root, num_bytes, empty_size,
1634 search_start, search_end, hint_byte, ins,
1635 trans->alloc_exclude_start,
1636 trans->alloc_exclude_nr, data);
1637 BUG_ON(ret);
1638 if (ret)
1639 return ret;
1640
1641 /* block accounting for super block */
1642 super_used = btrfs_super_bytes_used(&info->super_copy);
1643 btrfs_set_super_bytes_used(&info->super_copy, super_used + num_bytes);
1644
1645 /* block accounting for root item */
1646 root_used = btrfs_root_used(&root->root_item);
1647 btrfs_set_root_used(&root->root_item, root_used + num_bytes);
1648
1649 clear_extent_dirty(&root->fs_info->free_space_cache,
1650 ins->objectid, ins->objectid + ins->offset - 1,
1651 GFP_NOFS);
1652
1653 if (root == extent_root) {
1654 set_extent_bits(&root->fs_info->extent_ins, ins->objectid,
1655 ins->objectid + ins->offset - 1,
1656 EXTENT_LOCKED, GFP_NOFS);
1657 WARN_ON(data == 1);
1658 goto update_block;
1659 }
1660
1661 WARN_ON(trans->alloc_exclude_nr);
1662 trans->alloc_exclude_start = ins->objectid;
1663 trans->alloc_exclude_nr = ins->offset;
1664 ret = btrfs_insert_item(trans, extent_root, ins, &extent_item,
1665 sizeof(extent_item));
1666
1667 trans->alloc_exclude_start = 0;
1668 trans->alloc_exclude_nr = 0;
1669 BUG_ON(ret);
1670
1671 path = btrfs_alloc_path();
1672 BUG_ON(!path);
1673 ret = btrfs_insert_extent_backref(trans, extent_root, path,
1674 ins->objectid, root_objectid,
1675 ref_generation, owner, owner_offset);
1676
1677 BUG_ON(ret);
1678 btrfs_free_path(path);
1679 finish_current_insert(trans, extent_root);
1680 pending_ret = del_pending_extents(trans, extent_root);
1681
1682 if (ret) {
1683 return ret;
1684 }
1685 if (pending_ret) {
1686 return pending_ret;
1687 }
1688
1689 update_block:
1690 ret = update_block_group(trans, root, ins->objectid, ins->offset, 1, 0,
1691 data);
1692 BUG_ON(ret);
1693 return 0;
1694 }
1695
1696 /*
1697 * helper function to allocate a block for a given tree
1698 * returns the tree buffer or NULL.
1699 */
1700 struct extent_buffer *btrfs_alloc_free_block(struct btrfs_trans_handle *trans,
1701 struct btrfs_root *root,
1702 u32 blocksize,
1703 u64 root_objectid, u64 hint,
1704 u64 empty_size)
1705 {
1706 u64 ref_generation;
1707
1708 if (root->ref_cows)
1709 ref_generation = trans->transid;
1710 else
1711 ref_generation = 0;
1712
1713
1714 return __btrfs_alloc_free_block(trans, root, blocksize, root_objectid,
1715 ref_generation, 0, 0, hint, empty_size);
1716 }
1717
1718 /*
1719 * helper function to allocate a block for a given tree
1720 * returns the tree buffer or NULL.
1721 */
1722 struct extent_buffer *__btrfs_alloc_free_block(struct btrfs_trans_handle *trans,
1723 struct btrfs_root *root,
1724 u32 blocksize,
1725 u64 root_objectid,
1726 u64 ref_generation,
1727 u64 first_objectid,
1728 int level,
1729 u64 hint,
1730 u64 empty_size)
1731 {
1732 struct btrfs_key ins;
1733 int ret;
1734 struct extent_buffer *buf;
1735
1736 ret = btrfs_alloc_extent(trans, root, blocksize,
1737 root_objectid, ref_generation,
1738 level, first_objectid, empty_size, hint,
1739 (u64)-1, &ins, 0);
1740 if (ret) {
1741 BUG_ON(ret > 0);
1742 return ERR_PTR(ret);
1743 }
1744 buf = btrfs_find_create_tree_block(root, ins.objectid, blocksize);
1745 if (!buf) {
1746 btrfs_free_extent(trans, root, ins.objectid, blocksize,
1747 root->root_key.objectid, ref_generation,
1748 0, 0, 0);
1749 return ERR_PTR(-ENOMEM);
1750 }
1751 btrfs_set_buffer_uptodate(buf);
1752 set_extent_dirty(&trans->transaction->dirty_pages, buf->start,
1753 buf->start + buf->len - 1, GFP_NOFS);
1754 set_extent_bits(&BTRFS_I(root->fs_info->btree_inode)->extent_tree,
1755 buf->start, buf->start + buf->len - 1,
1756 EXTENT_CSUM, GFP_NOFS);
1757 buf->flags |= EXTENT_CSUM;
1758 btrfs_set_buffer_defrag(buf);
1759 trans->blocks_used++;
1760 return buf;
1761 }
1762
1763 static int drop_leaf_ref(struct btrfs_trans_handle *trans,
1764 struct btrfs_root *root, struct extent_buffer *leaf)
1765 {
1766 u64 leaf_owner;
1767 u64 leaf_generation;
1768 struct btrfs_key key;
1769 struct btrfs_file_extent_item *fi;
1770 int i;
1771 int nritems;
1772 int ret;
1773
1774 BUG_ON(!btrfs_is_leaf(leaf));
1775 nritems = btrfs_header_nritems(leaf);
1776 leaf_owner = btrfs_header_owner(leaf);
1777 leaf_generation = btrfs_header_generation(leaf);
1778
1779 for (i = 0; i < nritems; i++) {
1780 u64 disk_bytenr;
1781
1782 btrfs_item_key_to_cpu(leaf, &key, i);
1783 if (btrfs_key_type(&key) != BTRFS_EXTENT_DATA_KEY)
1784 continue;
1785 fi = btrfs_item_ptr(leaf, i, struct btrfs_file_extent_item);
1786 if (btrfs_file_extent_type(leaf, fi) ==
1787 BTRFS_FILE_EXTENT_INLINE)
1788 continue;
1789 /*
1790 * FIXME make sure to insert a trans record that
1791 * repeats the snapshot del on crash
1792 */
1793 disk_bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
1794 if (disk_bytenr == 0)
1795 continue;
1796 ret = btrfs_free_extent(trans, root, disk_bytenr,
1797 btrfs_file_extent_disk_num_bytes(leaf, fi),
1798 leaf_owner, leaf_generation,
1799 key.objectid, key.offset, 0);
1800 BUG_ON(ret);
1801 }
1802 return 0;
1803 }
1804
1805 static void reada_walk_down(struct btrfs_root *root,
1806 struct extent_buffer *node)
1807 {
1808 int i;
1809 u32 nritems;
1810 u64 bytenr;
1811 int ret;
1812 u32 refs;
1813 int level;
1814 u32 blocksize;
1815
1816 nritems = btrfs_header_nritems(node);
1817 level = btrfs_header_level(node);
1818 for (i = 0; i < nritems; i++) {
1819 bytenr = btrfs_node_blockptr(node, i);
1820 blocksize = btrfs_level_size(root, level - 1);
1821 ret = lookup_extent_ref(NULL, root, bytenr, blocksize, &refs);
1822 BUG_ON(ret);
1823 if (refs != 1)
1824 continue;
1825 mutex_unlock(&root->fs_info->fs_mutex);
1826 ret = readahead_tree_block(root, bytenr, blocksize);
1827 cond_resched();
1828 mutex_lock(&root->fs_info->fs_mutex);
1829 if (ret)
1830 break;
1831 }
1832 }
1833
1834 /*
1835 * helper function for drop_snapshot, this walks down the tree dropping ref
1836 * counts as it goes.
1837 */
1838 static int walk_down_tree(struct btrfs_trans_handle *trans, struct btrfs_root
1839 *root, struct btrfs_path *path, int *level)
1840 {
1841 u64 root_owner;
1842 u64 root_gen;
1843 u64 bytenr;
1844 struct extent_buffer *next;
1845 struct extent_buffer *cur;
1846 struct extent_buffer *parent;
1847 u32 blocksize;
1848 int ret;
1849 u32 refs;
1850
1851 WARN_ON(*level < 0);
1852 WARN_ON(*level >= BTRFS_MAX_LEVEL);
1853 ret = lookup_extent_ref(trans, root,
1854 path->nodes[*level]->start,
1855 path->nodes[*level]->len, &refs);
1856 BUG_ON(ret);
1857 if (refs > 1)
1858 goto out;
1859
1860 /*
1861 * walk down to the last node level and free all the leaves
1862 */
1863 while(*level >= 0) {
1864 WARN_ON(*level < 0);
1865 WARN_ON(*level >= BTRFS_MAX_LEVEL);
1866 cur = path->nodes[*level];
1867
1868 if (*level > 0 && path->slots[*level] == 0)
1869 reada_walk_down(root, cur);
1870
1871 if (btrfs_header_level(cur) != *level)
1872 WARN_ON(1);
1873
1874 if (path->slots[*level] >=
1875 btrfs_header_nritems(cur))
1876 break;
1877 if (*level == 0) {
1878 ret = drop_leaf_ref(trans, root, cur);
1879 BUG_ON(ret);
1880 break;
1881 }
1882 bytenr = btrfs_node_blockptr(cur, path->slots[*level]);
1883 blocksize = btrfs_level_size(root, *level - 1);
1884 ret = lookup_extent_ref(trans, root, bytenr, blocksize, &refs);
1885 BUG_ON(ret);
1886 if (refs != 1) {
1887 parent = path->nodes[*level];
1888 root_owner = btrfs_header_owner(parent);
1889 root_gen = btrfs_header_generation(parent);
1890 path->slots[*level]++;
1891 ret = btrfs_free_extent(trans, root, bytenr,
1892 blocksize, root_owner,
1893 root_gen, 0, 0, 1);
1894 BUG_ON(ret);
1895 continue;
1896 }
1897 next = btrfs_find_tree_block(root, bytenr, blocksize);
1898 if (!next || !btrfs_buffer_uptodate(next)) {
1899 free_extent_buffer(next);
1900 mutex_unlock(&root->fs_info->fs_mutex);
1901 next = read_tree_block(root, bytenr, blocksize);
1902 mutex_lock(&root->fs_info->fs_mutex);
1903
1904 /* we dropped the lock, check one more time */
1905 ret = lookup_extent_ref(trans, root, bytenr,
1906 blocksize, &refs);
1907 BUG_ON(ret);
1908 if (refs != 1) {
1909 parent = path->nodes[*level];
1910 root_owner = btrfs_header_owner(parent);
1911 root_gen = btrfs_header_generation(parent);
1912
1913 path->slots[*level]++;
1914 free_extent_buffer(next);
1915 ret = btrfs_free_extent(trans, root, bytenr,
1916 blocksize,
1917 root_owner,
1918 root_gen, 0, 0, 1);
1919 BUG_ON(ret);
1920 continue;
1921 }
1922 }
1923 WARN_ON(*level <= 0);
1924 if (path->nodes[*level-1])
1925 free_extent_buffer(path->nodes[*level-1]);
1926 path->nodes[*level-1] = next;
1927 *level = btrfs_header_level(next);
1928 path->slots[*level] = 0;
1929 }
1930 out:
1931 WARN_ON(*level < 0);
1932 WARN_ON(*level >= BTRFS_MAX_LEVEL);
1933
1934 if (path->nodes[*level] == root->node) {
1935 root_owner = root->root_key.objectid;
1936 parent = path->nodes[*level];
1937 } else {
1938 parent = path->nodes[*level + 1];
1939 root_owner = btrfs_header_owner(parent);
1940 }
1941
1942 root_gen = btrfs_header_generation(parent);
1943 ret = btrfs_free_extent(trans, root, path->nodes[*level]->start,
1944 path->nodes[*level]->len,
1945 root_owner, root_gen, 0, 0, 1);
1946 free_extent_buffer(path->nodes[*level]);
1947 path->nodes[*level] = NULL;
1948 *level += 1;
1949 BUG_ON(ret);
1950 return 0;
1951 }
1952
1953 /*
1954 * helper for dropping snapshots. This walks back up the tree in the path
1955 * to find the first node higher up where we haven't yet gone through
1956 * all the slots
1957 */
1958 static int walk_up_tree(struct btrfs_trans_handle *trans, struct btrfs_root
1959 *root, struct btrfs_path *path, int *level)
1960 {
1961 u64 root_owner;
1962 u64 root_gen;
1963 struct btrfs_root_item *root_item = &root->root_item;
1964 int i;
1965 int slot;
1966 int ret;
1967
1968 for(i = *level; i < BTRFS_MAX_LEVEL - 1 && path->nodes[i]; i++) {
1969 slot = path->slots[i];
1970 if (slot < btrfs_header_nritems(path->nodes[i]) - 1) {
1971 struct extent_buffer *node;
1972 struct btrfs_disk_key disk_key;
1973 node = path->nodes[i];
1974 path->slots[i]++;
1975 *level = i;
1976 WARN_ON(*level == 0);
1977 btrfs_node_key(node, &disk_key, path->slots[i]);
1978 memcpy(&root_item->drop_progress,
1979 &disk_key, sizeof(disk_key));
1980 root_item->drop_level = i;
1981 return 0;
1982 } else {
1983 if (path->nodes[*level] == root->node) {
1984 root_owner = root->root_key.objectid;
1985 root_gen =
1986 btrfs_header_generation(path->nodes[*level]);
1987 } else {
1988 struct extent_buffer *node;
1989 node = path->nodes[*level + 1];
1990 root_owner = btrfs_header_owner(node);
1991 root_gen = btrfs_header_generation(node);
1992 }
1993 ret = btrfs_free_extent(trans, root,
1994 path->nodes[*level]->start,
1995 path->nodes[*level]->len,
1996 root_owner, root_gen, 0, 0, 1);
1997 BUG_ON(ret);
1998 free_extent_buffer(path->nodes[*level]);
1999 path->nodes[*level] = NULL;
2000 *level = i + 1;
2001 }
2002 }
2003 return 1;
2004 }
2005
2006 /*
2007 * drop the reference count on the tree rooted at 'snap'. This traverses
2008 * the tree freeing any blocks that have a ref count of zero after being
2009 * decremented.
2010 */
2011 int btrfs_drop_snapshot(struct btrfs_trans_handle *trans, struct btrfs_root
2012 *root)
2013 {
2014 int ret = 0;
2015 int wret;
2016 int level;
2017 struct btrfs_path *path;
2018 int i;
2019 int orig_level;
2020 struct btrfs_root_item *root_item = &root->root_item;
2021
2022 path = btrfs_alloc_path();
2023 BUG_ON(!path);
2024
2025 level = btrfs_header_level(root->node);
2026 orig_level = level;
2027 if (btrfs_disk_key_objectid(&root_item->drop_progress) == 0) {
2028 path->nodes[level] = root->node;
2029 extent_buffer_get(root->node);
2030 path->slots[level] = 0;
2031 } else {
2032 struct btrfs_key key;
2033 struct btrfs_disk_key found_key;
2034 struct extent_buffer *node;
2035
2036 btrfs_disk_key_to_cpu(&key, &root_item->drop_progress);
2037 level = root_item->drop_level;
2038 path->lowest_level = level;
2039 wret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
2040 if (wret < 0) {
2041 ret = wret;
2042 goto out;
2043 }
2044 node = path->nodes[level];
2045 btrfs_node_key(node, &found_key, path->slots[level]);
2046 WARN_ON(memcmp(&found_key, &root_item->drop_progress,
2047 sizeof(found_key)));
2048 }
2049 while(1) {
2050 wret = walk_down_tree(trans, root, path, &level);
2051 if (wret > 0)
2052 break;
2053 if (wret < 0)
2054 ret = wret;
2055
2056 wret = walk_up_tree(trans, root, path, &level);
2057 if (wret > 0)
2058 break;
2059 if (wret < 0)
2060 ret = wret;
2061 ret = -EAGAIN;
2062 break;
2063 }
2064 for (i = 0; i <= orig_level; i++) {
2065 if (path->nodes[i]) {
2066 free_extent_buffer(path->nodes[i]);
2067 path->nodes[i] = NULL;
2068 }
2069 }
2070 out:
2071 btrfs_free_path(path);
2072 return ret;
2073 }
2074
2075 int btrfs_free_block_groups(struct btrfs_fs_info *info)
2076 {
2077 u64 start;
2078 u64 end;
2079 u64 ptr;
2080 int ret;
2081 while(1) {
2082 ret = find_first_extent_bit(&info->block_group_cache, 0,
2083 &start, &end, (unsigned int)-1);
2084 if (ret)
2085 break;
2086 ret = get_state_private(&info->block_group_cache, start, &ptr);
2087 if (!ret)
2088 kfree((void *)(unsigned long)ptr);
2089 clear_extent_bits(&info->block_group_cache, start,
2090 end, (unsigned int)-1, GFP_NOFS);
2091 }
2092 while(1) {
2093 ret = find_first_extent_bit(&info->free_space_cache, 0,
2094 &start, &end, EXTENT_DIRTY);
2095 if (ret)
2096 break;
2097 clear_extent_dirty(&info->free_space_cache, start,
2098 end, GFP_NOFS);
2099 }
2100 return 0;
2101 }
2102
2103 int btrfs_read_block_groups(struct btrfs_root *root)
2104 {
2105 struct btrfs_path *path;
2106 int ret;
2107 int err = 0;
2108 int bit;
2109 struct btrfs_block_group_cache *cache;
2110 struct btrfs_fs_info *info = root->fs_info;
2111 struct extent_map_tree *block_group_cache;
2112 struct btrfs_key key;
2113 struct btrfs_key found_key;
2114 struct extent_buffer *leaf;
2115
2116 block_group_cache = &info->block_group_cache;
2117
2118 root = info->extent_root;
2119 key.objectid = 0;
2120 key.offset = BTRFS_BLOCK_GROUP_SIZE;
2121 btrfs_set_key_type(&key, BTRFS_BLOCK_GROUP_ITEM_KEY);
2122
2123 path = btrfs_alloc_path();
2124 if (!path)
2125 return -ENOMEM;
2126
2127 while(1) {
2128 ret = btrfs_search_slot(NULL, info->extent_root,
2129 &key, path, 0, 0);
2130 if (ret != 0) {
2131 err = ret;
2132 break;
2133 }
2134 leaf = path->nodes[0];
2135 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
2136 cache = kmalloc(sizeof(*cache), GFP_NOFS);
2137 if (!cache) {
2138 err = -1;
2139 break;
2140 }
2141
2142 read_extent_buffer(leaf, &cache->item,
2143 btrfs_item_ptr_offset(leaf, path->slots[0]),
2144 sizeof(cache->item));
2145 memcpy(&cache->key, &found_key, sizeof(found_key));
2146 cache->cached = 0;
2147 cache->pinned = 0;
2148 key.objectid = found_key.objectid + found_key.offset;
2149 btrfs_release_path(root, path);
2150
2151 if (cache->item.flags & BTRFS_BLOCK_GROUP_MIXED) {
2152 bit = BLOCK_GROUP_DATA | BLOCK_GROUP_METADATA;
2153 cache->data = BTRFS_BLOCK_GROUP_MIXED;
2154 } else if (cache->item.flags & BTRFS_BLOCK_GROUP_DATA) {
2155 bit = BLOCK_GROUP_DATA;
2156 cache->data = BTRFS_BLOCK_GROUP_DATA;
2157 } else {
2158 bit = BLOCK_GROUP_METADATA;
2159 cache->data = 0;
2160 }
2161
2162 /* use EXTENT_LOCKED to prevent merging */
2163 set_extent_bits(block_group_cache, found_key.objectid,
2164 found_key.objectid + found_key.offset - 1,
2165 bit | EXTENT_LOCKED, GFP_NOFS);
2166 set_state_private(block_group_cache, found_key.objectid,
2167 (unsigned long)cache);
2168
2169 if (key.objectid >=
2170 btrfs_super_total_bytes(&info->super_copy))
2171 break;
2172 }
2173
2174 btrfs_free_path(path);
2175 return 0;
2176 }
Linux kernel - Deliverables
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