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Btrfs: Allocator improvements
[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 <linux/pagemap.h>
22 #include "hash.h"
23 #include "ctree.h"
24 #include "disk-io.h"
25 #include "print-tree.h"
26 #include "transaction.h"
27
28 #define BLOCK_GROUP_DATA EXTENT_WRITEBACK
29 #define BLOCK_GROUP_METADATA EXTENT_UPTODATE
30 #define BLOCK_GROUP_DIRTY EXTENT_DIRTY
31
32 static int finish_current_insert(struct btrfs_trans_handle *trans, struct
33 btrfs_root *extent_root);
34 static int del_pending_extents(struct btrfs_trans_handle *trans, struct
35 btrfs_root *extent_root);
36 static int find_previous_extent(struct btrfs_root *root,
37 struct btrfs_path *path)
38 {
39 struct btrfs_key found_key;
40 struct extent_buffer *leaf;
41 int ret;
42
43 while(1) {
44 if (path->slots[0] == 0) {
45 ret = btrfs_prev_leaf(root, path);
46 if (ret != 0)
47 return ret;
48 } else {
49 path->slots[0]--;
50 }
51 leaf = path->nodes[0];
52 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
53 if (found_key.type == BTRFS_EXTENT_ITEM_KEY)
54 return 0;
55 }
56 return 1;
57 }
58
59 static int cache_block_group(struct btrfs_root *root,
60 struct btrfs_block_group_cache *block_group)
61 {
62 struct btrfs_path *path;
63 int ret;
64 struct btrfs_key key;
65 struct extent_buffer *leaf;
66 struct extent_io_tree *free_space_cache;
67 int slot;
68 u64 last = 0;
69 u64 hole_size;
70 u64 first_free;
71 int found = 0;
72
73 if (!block_group)
74 return 0;
75
76 root = root->fs_info->extent_root;
77 free_space_cache = &root->fs_info->free_space_cache;
78
79 if (block_group->cached)
80 return 0;
81
82 path = btrfs_alloc_path();
83 if (!path)
84 return -ENOMEM;
85
86 path->reada = 2;
87 first_free = block_group->key.objectid;
88 key.objectid = block_group->key.objectid;
89 key.offset = 0;
90 btrfs_set_key_type(&key, BTRFS_EXTENT_ITEM_KEY);
91 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
92 if (ret < 0)
93 return ret;
94 ret = find_previous_extent(root, path);
95 if (ret < 0)
96 return ret;
97 if (ret == 0) {
98 leaf = path->nodes[0];
99 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
100 if (key.objectid + key.offset > first_free)
101 first_free = key.objectid + key.offset;
102 }
103 while(1) {
104 leaf = path->nodes[0];
105 slot = path->slots[0];
106 if (slot >= btrfs_header_nritems(leaf)) {
107 ret = btrfs_next_leaf(root, path);
108 if (ret < 0)
109 goto err;
110 if (ret == 0) {
111 continue;
112 } else {
113 break;
114 }
115 }
116 btrfs_item_key_to_cpu(leaf, &key, slot);
117 if (key.objectid < block_group->key.objectid) {
118 goto next;
119 }
120 if (key.objectid >= block_group->key.objectid +
121 block_group->key.offset) {
122 break;
123 }
124
125 if (btrfs_key_type(&key) == BTRFS_EXTENT_ITEM_KEY) {
126 if (!found) {
127 last = first_free;
128 found = 1;
129 }
130 if (key.objectid > last) {
131 hole_size = key.objectid - last;
132 set_extent_dirty(free_space_cache, last,
133 last + hole_size - 1,
134 GFP_NOFS);
135 }
136 last = key.objectid + key.offset;
137 }
138 next:
139 path->slots[0]++;
140 }
141
142 if (!found)
143 last = first_free;
144 if (block_group->key.objectid +
145 block_group->key.offset > last) {
146 hole_size = block_group->key.objectid +
147 block_group->key.offset - last;
148 set_extent_dirty(free_space_cache, last,
149 last + hole_size - 1, GFP_NOFS);
150 }
151 block_group->cached = 1;
152 err:
153 btrfs_free_path(path);
154 return 0;
155 }
156
157 struct btrfs_block_group_cache *btrfs_lookup_block_group(struct
158 btrfs_fs_info *info,
159 u64 bytenr)
160 {
161 struct extent_io_tree *block_group_cache;
162 struct btrfs_block_group_cache *block_group = NULL;
163 u64 ptr;
164 u64 start;
165 u64 end;
166 int ret;
167
168 block_group_cache = &info->block_group_cache;
169 ret = find_first_extent_bit(block_group_cache,
170 bytenr, &start, &end,
171 BLOCK_GROUP_DATA | BLOCK_GROUP_METADATA);
172 if (ret) {
173 return NULL;
174 }
175 ret = get_state_private(block_group_cache, start, &ptr);
176 if (ret)
177 return NULL;
178
179 block_group = (struct btrfs_block_group_cache *)(unsigned long)ptr;
180 if (block_group->key.objectid <= bytenr && bytenr <
181 block_group->key.objectid + block_group->key.offset)
182 return block_group;
183 return NULL;
184 }
185 static u64 noinline find_search_start(struct btrfs_root *root,
186 struct btrfs_block_group_cache **cache_ret,
187 u64 search_start, int num, int data)
188 {
189 int ret;
190 struct btrfs_block_group_cache *cache = *cache_ret;
191 struct extent_io_tree *free_space_cache;
192 struct extent_state *state;
193 u64 last;
194 u64 start = 0;
195 u64 cache_miss = 0;
196 u64 total_fs_bytes;
197 int wrapped = 0;
198
199 if (!cache) {
200 goto out;
201 }
202 total_fs_bytes = btrfs_super_total_bytes(&root->fs_info->super_copy);
203 free_space_cache = &root->fs_info->free_space_cache;
204
205 again:
206 ret = cache_block_group(root, cache);
207 if (ret)
208 goto out;
209
210 last = max(search_start, cache->key.objectid);
211
212 spin_lock_irq(&free_space_cache->lock);
213 state = find_first_extent_bit_state(free_space_cache, last, EXTENT_DIRTY);
214 while(1) {
215 if (!state) {
216 if (!cache_miss)
217 cache_miss = last;
218 spin_unlock_irq(&free_space_cache->lock);
219 goto new_group;
220 }
221
222 start = max(last, state->start);
223 last = state->end + 1;
224 if (last - start < num) {
225 if (last == cache->key.objectid + cache->key.offset)
226 cache_miss = start;
227 do {
228 state = extent_state_next(state);
229 } while(state && !(state->state & EXTENT_DIRTY));
230 continue;
231 }
232 spin_unlock_irq(&free_space_cache->lock);
233 if (data != BTRFS_BLOCK_GROUP_MIXED &&
234 start + num > cache->key.objectid + cache->key.offset)
235 goto new_group;
236 if (start + num > total_fs_bytes)
237 goto new_group;
238 return start;
239 }
240 out:
241 cache = btrfs_lookup_block_group(root->fs_info, search_start);
242 if (!cache) {
243 printk("Unable to find block group for %Lu\n",
244 search_start);
245 WARN_ON(1);
246 return search_start;
247 }
248 return search_start;
249
250 new_group:
251 last = cache->key.objectid + cache->key.offset;
252 wrapped:
253 cache = btrfs_lookup_block_group(root->fs_info, last);
254 if (!cache || cache->key.objectid >= total_fs_bytes) {
255 no_cache:
256 if (!wrapped) {
257 wrapped = 1;
258 last = search_start;
259 data = BTRFS_BLOCK_GROUP_MIXED;
260 goto wrapped;
261 }
262 goto out;
263 }
264 if (cache_miss && !cache->cached) {
265 cache_block_group(root, cache);
266 last = cache_miss;
267 cache = btrfs_lookup_block_group(root->fs_info, last);
268 }
269 cache = btrfs_find_block_group(root, cache, last, data, 0);
270 if (!cache)
271 goto no_cache;
272 *cache_ret = cache;
273 cache_miss = 0;
274 goto again;
275 }
276
277 static u64 div_factor(u64 num, int factor)
278 {
279 if (factor == 10)
280 return num;
281 num *= factor;
282 do_div(num, 10);
283 return num;
284 }
285
286 struct btrfs_block_group_cache *btrfs_find_block_group(struct btrfs_root *root,
287 struct btrfs_block_group_cache
288 *hint, u64 search_start,
289 int data, int owner)
290 {
291 struct btrfs_block_group_cache *cache;
292 struct extent_io_tree *block_group_cache;
293 struct btrfs_block_group_cache *found_group = NULL;
294 struct btrfs_fs_info *info = root->fs_info;
295 u64 used;
296 u64 last = 0;
297 u64 hint_last;
298 u64 start;
299 u64 end;
300 u64 free_check;
301 u64 ptr;
302 u64 total_fs_bytes;
303 int bit;
304 int ret;
305 int full_search = 0;
306 int factor = 8;
307 int data_swap = 0;
308
309 block_group_cache = &info->block_group_cache;
310 total_fs_bytes = btrfs_super_total_bytes(&root->fs_info->super_copy);
311
312 if (!owner)
313 factor = 8;
314
315 if (data == BTRFS_BLOCK_GROUP_MIXED) {
316 bit = BLOCK_GROUP_DATA | BLOCK_GROUP_METADATA;
317 factor = 10;
318 } else if (data)
319 bit = BLOCK_GROUP_DATA;
320 else
321 bit = BLOCK_GROUP_METADATA;
322
323 if (search_start && search_start < total_fs_bytes) {
324 struct btrfs_block_group_cache *shint;
325 shint = btrfs_lookup_block_group(info, search_start);
326 if (shint && (shint->data == data ||
327 shint->data == BTRFS_BLOCK_GROUP_MIXED)) {
328 used = btrfs_block_group_used(&shint->item);
329 if (used + shint->pinned <
330 div_factor(shint->key.offset, factor)) {
331 return shint;
332 }
333 }
334 }
335 if (hint && hint->key.objectid < total_fs_bytes &&
336 (hint->data == data || hint->data == BTRFS_BLOCK_GROUP_MIXED)) {
337 used = btrfs_block_group_used(&hint->item);
338 if (used + hint->pinned <
339 div_factor(hint->key.offset, factor)) {
340 return hint;
341 }
342 last = hint->key.objectid + hint->key.offset;
343 hint_last = last;
344 } else {
345 if (hint)
346 hint_last = max(hint->key.objectid, search_start);
347 else
348 hint_last = search_start;
349
350 if (hint_last >= total_fs_bytes)
351 hint_last = search_start;
352 last = hint_last;
353 }
354 again:
355 while(1) {
356 ret = find_first_extent_bit(block_group_cache, last,
357 &start, &end, bit);
358 if (ret)
359 break;
360
361 ret = get_state_private(block_group_cache, start, &ptr);
362 if (ret)
363 break;
364
365 cache = (struct btrfs_block_group_cache *)(unsigned long)ptr;
366 last = cache->key.objectid + cache->key.offset;
367 used = btrfs_block_group_used(&cache->item);
368
369 if (cache->key.objectid > total_fs_bytes)
370 break;
371
372 if (full_search)
373 free_check = cache->key.offset;
374 else
375 free_check = div_factor(cache->key.offset, factor);
376 if (used + cache->pinned < free_check) {
377 found_group = cache;
378 goto found;
379 }
380 cond_resched();
381 }
382 if (!full_search) {
383 last = search_start;
384 full_search = 1;
385 goto again;
386 }
387 if (!data_swap) {
388 data_swap = 1;
389 bit = BLOCK_GROUP_DATA | BLOCK_GROUP_METADATA;
390 last = search_start;
391 goto again;
392 }
393 found:
394 return found_group;
395 }
396
397 static u64 hash_extent_ref(u64 root_objectid, u64 ref_generation,
398 u64 owner, u64 owner_offset)
399 {
400 u32 high_crc = ~(u32)0;
401 u32 low_crc = ~(u32)0;
402 __le64 lenum;
403
404 lenum = cpu_to_le64(root_objectid);
405 high_crc = crc32c(high_crc, &lenum, sizeof(lenum));
406 lenum = cpu_to_le64(ref_generation);
407 low_crc = crc32c(low_crc, &lenum, sizeof(lenum));
408 if (owner >= BTRFS_FIRST_FREE_OBJECTID) {
409 lenum = cpu_to_le64(owner);
410 low_crc = crc32c(low_crc, &lenum, sizeof(lenum));
411 lenum = cpu_to_le64(owner_offset);
412 low_crc = crc32c(low_crc, &lenum, sizeof(lenum));
413 }
414 return ((u64)high_crc << 32) | (u64)low_crc;
415 }
416
417 static int match_extent_ref(struct extent_buffer *leaf,
418 struct btrfs_extent_ref *disk_ref,
419 struct btrfs_extent_ref *cpu_ref)
420 {
421 int ret;
422 int len;
423
424 if (cpu_ref->objectid)
425 len = sizeof(*cpu_ref);
426 else
427 len = 2 * sizeof(u64);
428 ret = memcmp_extent_buffer(leaf, cpu_ref, (unsigned long)disk_ref,
429 len);
430 return ret == 0;
431 }
432
433 static int noinline lookup_extent_backref(struct btrfs_trans_handle *trans,
434 struct btrfs_root *root,
435 struct btrfs_path *path, u64 bytenr,
436 u64 root_objectid,
437 u64 ref_generation, u64 owner,
438 u64 owner_offset, int del)
439 {
440 u64 hash;
441 struct btrfs_key key;
442 struct btrfs_key found_key;
443 struct btrfs_extent_ref ref;
444 struct extent_buffer *leaf;
445 struct btrfs_extent_ref *disk_ref;
446 int ret;
447 int ret2;
448
449 btrfs_set_stack_ref_root(&ref, root_objectid);
450 btrfs_set_stack_ref_generation(&ref, ref_generation);
451 btrfs_set_stack_ref_objectid(&ref, owner);
452 btrfs_set_stack_ref_offset(&ref, owner_offset);
453
454 hash = hash_extent_ref(root_objectid, ref_generation, owner,
455 owner_offset);
456 key.offset = hash;
457 key.objectid = bytenr;
458 key.type = BTRFS_EXTENT_REF_KEY;
459
460 while (1) {
461 ret = btrfs_search_slot(trans, root, &key, path,
462 del ? -1 : 0, del);
463 if (ret < 0)
464 goto out;
465 leaf = path->nodes[0];
466 if (ret != 0) {
467 u32 nritems = btrfs_header_nritems(leaf);
468 if (path->slots[0] >= nritems) {
469 ret2 = btrfs_next_leaf(root, path);
470 if (ret2)
471 goto out;
472 leaf = path->nodes[0];
473 }
474 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
475 if (found_key.objectid != bytenr ||
476 found_key.type != BTRFS_EXTENT_REF_KEY)
477 goto out;
478 key.offset = found_key.offset;
479 if (del) {
480 btrfs_release_path(root, path);
481 continue;
482 }
483 }
484 disk_ref = btrfs_item_ptr(path->nodes[0],
485 path->slots[0],
486 struct btrfs_extent_ref);
487 if (match_extent_ref(path->nodes[0], disk_ref, &ref)) {
488 ret = 0;
489 goto out;
490 }
491 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
492 key.offset = found_key.offset + 1;
493 btrfs_release_path(root, path);
494 }
495 out:
496 return ret;
497 }
498
499 /*
500 * Back reference rules. Back refs have three main goals:
501 *
502 * 1) differentiate between all holders of references to an extent so that
503 * when a reference is dropped we can make sure it was a valid reference
504 * before freeing the extent.
505 *
506 * 2) Provide enough information to quickly find the holders of an extent
507 * if we notice a given block is corrupted or bad.
508 *
509 * 3) Make it easy to migrate blocks for FS shrinking or storage pool
510 * maintenance. This is actually the same as #2, but with a slightly
511 * different use case.
512 *
513 * File extents can be referenced by:
514 *
515 * - multiple snapshots, subvolumes, or different generations in one subvol
516 * - different files inside a single subvolume (in theory, not implemented yet)
517 * - different offsets inside a file (bookend extents in file.c)
518 *
519 * The extent ref structure has fields for:
520 *
521 * - Objectid of the subvolume root
522 * - Generation number of the tree holding the reference
523 * - objectid of the file holding the reference
524 * - offset in the file corresponding to the key holding the reference
525 *
526 * When a file extent is allocated the fields are filled in:
527 * (root_key.objectid, trans->transid, inode objectid, offset in file)
528 *
529 * When a leaf is cow'd new references are added for every file extent found
530 * in the leaf. It looks the same as the create case, but trans->transid
531 * will be different when the block is cow'd.
532 *
533 * (root_key.objectid, trans->transid, inode objectid, offset in file)
534 *
535 * When a file extent is removed either during snapshot deletion or file
536 * truncation, the corresponding back reference is found
537 * by searching for:
538 *
539 * (btrfs_header_owner(leaf), btrfs_header_generation(leaf),
540 * inode objectid, offset in file)
541 *
542 * Btree extents can be referenced by:
543 *
544 * - Different subvolumes
545 * - Different generations of the same subvolume
546 *
547 * Storing sufficient information for a full reverse mapping of a btree
548 * block would require storing the lowest key of the block in the backref,
549 * and it would require updating that lowest key either before write out or
550 * every time it changed. Instead, the objectid of the lowest key is stored
551 * along with the level of the tree block. This provides a hint
552 * about where in the btree the block can be found. Searches through the
553 * btree only need to look for a pointer to that block, so they stop one
554 * level higher than the level recorded in the backref.
555 *
556 * Some btrees do not do reference counting on their extents. These
557 * include the extent tree and the tree of tree roots. Backrefs for these
558 * trees always have a generation of zero.
559 *
560 * When a tree block is created, back references are inserted:
561 *
562 * (root->root_key.objectid, trans->transid or zero, level, lowest_key_objectid)
563 *
564 * When a tree block is cow'd in a reference counted root,
565 * new back references are added for all the blocks it points to.
566 * These are of the form (trans->transid will have increased since creation):
567 *
568 * (root->root_key.objectid, trans->transid, level, lowest_key_objectid)
569 *
570 * Because the lowest_key_objectid and the level are just hints
571 * they are not used when backrefs are deleted. When a backref is deleted:
572 *
573 * if backref was for a tree root:
574 * root_objectid = root->root_key.objectid
575 * else
576 * root_objectid = btrfs_header_owner(parent)
577 *
578 * (root_objectid, btrfs_header_generation(parent) or zero, 0, 0)
579 *
580 * Back Reference Key hashing:
581 *
582 * Back references have four fields, each 64 bits long. Unfortunately,
583 * This is hashed into a single 64 bit number and placed into the key offset.
584 * The key objectid corresponds to the first byte in the extent, and the
585 * key type is set to BTRFS_EXTENT_REF_KEY
586 */
587 int btrfs_insert_extent_backref(struct btrfs_trans_handle *trans,
588 struct btrfs_root *root,
589 struct btrfs_path *path, u64 bytenr,
590 u64 root_objectid, u64 ref_generation,
591 u64 owner, u64 owner_offset)
592 {
593 u64 hash;
594 struct btrfs_key key;
595 struct btrfs_extent_ref ref;
596 struct btrfs_extent_ref *disk_ref;
597 int ret;
598
599 btrfs_set_stack_ref_root(&ref, root_objectid);
600 btrfs_set_stack_ref_generation(&ref, ref_generation);
601 btrfs_set_stack_ref_objectid(&ref, owner);
602 btrfs_set_stack_ref_offset(&ref, owner_offset);
603
604 hash = hash_extent_ref(root_objectid, ref_generation, owner,
605 owner_offset);
606 key.offset = hash;
607 key.objectid = bytenr;
608 key.type = BTRFS_EXTENT_REF_KEY;
609
610 ret = btrfs_insert_empty_item(trans, root, path, &key, sizeof(ref));
611 while (ret == -EEXIST) {
612 disk_ref = btrfs_item_ptr(path->nodes[0], path->slots[0],
613 struct btrfs_extent_ref);
614 if (match_extent_ref(path->nodes[0], disk_ref, &ref))
615 goto out;
616 key.offset++;
617 btrfs_release_path(root, path);
618 ret = btrfs_insert_empty_item(trans, root, path, &key,
619 sizeof(ref));
620 }
621 if (ret)
622 goto out;
623 disk_ref = btrfs_item_ptr(path->nodes[0], path->slots[0],
624 struct btrfs_extent_ref);
625 write_extent_buffer(path->nodes[0], &ref, (unsigned long)disk_ref,
626 sizeof(ref));
627 btrfs_mark_buffer_dirty(path->nodes[0]);
628 out:
629 btrfs_release_path(root, path);
630 return ret;
631 }
632
633 int btrfs_inc_extent_ref(struct btrfs_trans_handle *trans,
634 struct btrfs_root *root,
635 u64 bytenr, u64 num_bytes,
636 u64 root_objectid, u64 ref_generation,
637 u64 owner, u64 owner_offset)
638 {
639 struct btrfs_path *path;
640 int ret;
641 struct btrfs_key key;
642 struct extent_buffer *l;
643 struct btrfs_extent_item *item;
644 u32 refs;
645
646 WARN_ON(num_bytes < root->sectorsize);
647 path = btrfs_alloc_path();
648 if (!path)
649 return -ENOMEM;
650
651 path->reada = 0;
652 key.objectid = bytenr;
653 btrfs_set_key_type(&key, BTRFS_EXTENT_ITEM_KEY);
654 key.offset = num_bytes;
655 ret = btrfs_search_slot(trans, root->fs_info->extent_root, &key, path,
656 0, 1);
657 if (ret < 0)
658 return ret;
659 if (ret != 0) {
660 BUG();
661 }
662 BUG_ON(ret != 0);
663 l = path->nodes[0];
664 item = btrfs_item_ptr(l, path->slots[0], struct btrfs_extent_item);
665 refs = btrfs_extent_refs(l, item);
666 btrfs_set_extent_refs(l, item, refs + 1);
667 btrfs_mark_buffer_dirty(path->nodes[0]);
668
669 btrfs_release_path(root->fs_info->extent_root, path);
670
671 path->reada = 0;
672 ret = btrfs_insert_extent_backref(trans, root->fs_info->extent_root,
673 path, bytenr, root_objectid,
674 ref_generation, owner, owner_offset);
675 BUG_ON(ret);
676 finish_current_insert(trans, root->fs_info->extent_root);
677 del_pending_extents(trans, root->fs_info->extent_root);
678
679 btrfs_free_path(path);
680 return 0;
681 }
682
683 int btrfs_extent_post_op(struct btrfs_trans_handle *trans,
684 struct btrfs_root *root)
685 {
686 finish_current_insert(trans, root->fs_info->extent_root);
687 del_pending_extents(trans, root->fs_info->extent_root);
688 return 0;
689 }
690
691 static int lookup_extent_ref(struct btrfs_trans_handle *trans,
692 struct btrfs_root *root, u64 bytenr,
693 u64 num_bytes, u32 *refs)
694 {
695 struct btrfs_path *path;
696 int ret;
697 struct btrfs_key key;
698 struct extent_buffer *l;
699 struct btrfs_extent_item *item;
700
701 WARN_ON(num_bytes < root->sectorsize);
702 path = btrfs_alloc_path();
703 path->reada = 0;
704 key.objectid = bytenr;
705 key.offset = num_bytes;
706 btrfs_set_key_type(&key, BTRFS_EXTENT_ITEM_KEY);
707 ret = btrfs_search_slot(trans, root->fs_info->extent_root, &key, path,
708 0, 0);
709 if (ret < 0)
710 goto out;
711 if (ret != 0) {
712 btrfs_print_leaf(root, path->nodes[0]);
713 printk("failed to find block number %Lu\n", bytenr);
714 BUG();
715 }
716 l = path->nodes[0];
717 item = btrfs_item_ptr(l, path->slots[0], struct btrfs_extent_item);
718 *refs = btrfs_extent_refs(l, item);
719 out:
720 btrfs_free_path(path);
721 return 0;
722 }
723
724 u32 btrfs_count_snapshots_in_path(struct btrfs_root *root,
725 struct btrfs_path *count_path,
726 u64 first_extent)
727 {
728 struct btrfs_root *extent_root = root->fs_info->extent_root;
729 struct btrfs_path *path;
730 u64 bytenr;
731 u64 found_objectid;
732 u64 root_objectid = root->root_key.objectid;
733 u32 total_count = 0;
734 u32 cur_count;
735 u32 nritems;
736 int ret;
737 struct btrfs_key key;
738 struct btrfs_key found_key;
739 struct extent_buffer *l;
740 struct btrfs_extent_item *item;
741 struct btrfs_extent_ref *ref_item;
742 int level = -1;
743
744 path = btrfs_alloc_path();
745 again:
746 if (level == -1)
747 bytenr = first_extent;
748 else
749 bytenr = count_path->nodes[level]->start;
750
751 cur_count = 0;
752 key.objectid = bytenr;
753 key.offset = 0;
754
755 btrfs_set_key_type(&key, BTRFS_EXTENT_ITEM_KEY);
756 ret = btrfs_search_slot(NULL, extent_root, &key, path, 0, 0);
757 if (ret < 0)
758 goto out;
759 BUG_ON(ret == 0);
760
761 l = path->nodes[0];
762 btrfs_item_key_to_cpu(l, &found_key, path->slots[0]);
763
764 if (found_key.objectid != bytenr ||
765 found_key.type != BTRFS_EXTENT_ITEM_KEY) {
766 goto out;
767 }
768
769 item = btrfs_item_ptr(l, path->slots[0], struct btrfs_extent_item);
770 while (1) {
771 l = path->nodes[0];
772 nritems = btrfs_header_nritems(l);
773 if (path->slots[0] >= nritems) {
774 ret = btrfs_next_leaf(extent_root, path);
775 if (ret == 0)
776 continue;
777 break;
778 }
779 btrfs_item_key_to_cpu(l, &found_key, path->slots[0]);
780 if (found_key.objectid != bytenr)
781 break;
782
783 if (found_key.type != BTRFS_EXTENT_REF_KEY) {
784 path->slots[0]++;
785 continue;
786 }
787
788 cur_count++;
789 ref_item = btrfs_item_ptr(l, path->slots[0],
790 struct btrfs_extent_ref);
791 found_objectid = btrfs_ref_root(l, ref_item);
792
793 if (found_objectid != root_objectid) {
794 total_count = 2;
795 goto out;
796 }
797 total_count = 1;
798 path->slots[0]++;
799 }
800 if (cur_count == 0) {
801 total_count = 0;
802 goto out;
803 }
804 if (level >= 0 && root->node == count_path->nodes[level])
805 goto out;
806 level++;
807 btrfs_release_path(root, path);
808 goto again;
809
810 out:
811 btrfs_free_path(path);
812 return total_count;
813 }
814 int btrfs_inc_root_ref(struct btrfs_trans_handle *trans,
815 struct btrfs_root *root, u64 owner_objectid)
816 {
817 u64 generation;
818 u64 key_objectid;
819 u64 level;
820 u32 nritems;
821 struct btrfs_disk_key disk_key;
822
823 level = btrfs_header_level(root->node);
824 generation = trans->transid;
825 nritems = btrfs_header_nritems(root->node);
826 if (nritems > 0) {
827 if (level == 0)
828 btrfs_item_key(root->node, &disk_key, 0);
829 else
830 btrfs_node_key(root->node, &disk_key, 0);
831 key_objectid = btrfs_disk_key_objectid(&disk_key);
832 } else {
833 key_objectid = 0;
834 }
835 return btrfs_inc_extent_ref(trans, root, root->node->start,
836 root->node->len, owner_objectid,
837 generation, level, key_objectid);
838 }
839
840 int btrfs_inc_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root,
841 struct extent_buffer *buf)
842 {
843 u64 bytenr;
844 u32 nritems;
845 struct btrfs_key key;
846 struct btrfs_file_extent_item *fi;
847 int i;
848 int level;
849 int ret;
850 int faili;
851
852 if (!root->ref_cows)
853 return 0;
854
855 level = btrfs_header_level(buf);
856 nritems = btrfs_header_nritems(buf);
857 for (i = 0; i < nritems; i++) {
858 if (level == 0) {
859 u64 disk_bytenr;
860 btrfs_item_key_to_cpu(buf, &key, i);
861 if (btrfs_key_type(&key) != BTRFS_EXTENT_DATA_KEY)
862 continue;
863 fi = btrfs_item_ptr(buf, i,
864 struct btrfs_file_extent_item);
865 if (btrfs_file_extent_type(buf, fi) ==
866 BTRFS_FILE_EXTENT_INLINE)
867 continue;
868 disk_bytenr = btrfs_file_extent_disk_bytenr(buf, fi);
869 if (disk_bytenr == 0)
870 continue;
871 ret = btrfs_inc_extent_ref(trans, root, disk_bytenr,
872 btrfs_file_extent_disk_num_bytes(buf, fi),
873 root->root_key.objectid, trans->transid,
874 key.objectid, key.offset);
875 if (ret) {
876 faili = i;
877 goto fail;
878 }
879 } else {
880 bytenr = btrfs_node_blockptr(buf, i);
881 btrfs_node_key_to_cpu(buf, &key, i);
882 ret = btrfs_inc_extent_ref(trans, root, bytenr,
883 btrfs_level_size(root, level - 1),
884 root->root_key.objectid,
885 trans->transid,
886 level - 1, key.objectid);
887 if (ret) {
888 faili = i;
889 goto fail;
890 }
891 }
892 }
893 return 0;
894 fail:
895 WARN_ON(1);
896 #if 0
897 for (i =0; i < faili; i++) {
898 if (level == 0) {
899 u64 disk_bytenr;
900 btrfs_item_key_to_cpu(buf, &key, i);
901 if (btrfs_key_type(&key) != BTRFS_EXTENT_DATA_KEY)
902 continue;
903 fi = btrfs_item_ptr(buf, i,
904 struct btrfs_file_extent_item);
905 if (btrfs_file_extent_type(buf, fi) ==
906 BTRFS_FILE_EXTENT_INLINE)
907 continue;
908 disk_bytenr = btrfs_file_extent_disk_bytenr(buf, fi);
909 if (disk_bytenr == 0)
910 continue;
911 err = btrfs_free_extent(trans, root, disk_bytenr,
912 btrfs_file_extent_disk_num_bytes(buf,
913 fi), 0);
914 BUG_ON(err);
915 } else {
916 bytenr = btrfs_node_blockptr(buf, i);
917 err = btrfs_free_extent(trans, root, bytenr,
918 btrfs_level_size(root, level - 1), 0);
919 BUG_ON(err);
920 }
921 }
922 #endif
923 return ret;
924 }
925
926 static int write_one_cache_group(struct btrfs_trans_handle *trans,
927 struct btrfs_root *root,
928 struct btrfs_path *path,
929 struct btrfs_block_group_cache *cache)
930 {
931 int ret;
932 int pending_ret;
933 struct btrfs_root *extent_root = root->fs_info->extent_root;
934 unsigned long bi;
935 struct extent_buffer *leaf;
936
937 ret = btrfs_search_slot(trans, extent_root, &cache->key, path, 0, 1);
938 if (ret < 0)
939 goto fail;
940 BUG_ON(ret);
941
942 leaf = path->nodes[0];
943 bi = btrfs_item_ptr_offset(leaf, path->slots[0]);
944 write_extent_buffer(leaf, &cache->item, bi, sizeof(cache->item));
945 btrfs_mark_buffer_dirty(leaf);
946 btrfs_release_path(extent_root, path);
947 fail:
948 finish_current_insert(trans, extent_root);
949 pending_ret = del_pending_extents(trans, extent_root);
950 if (ret)
951 return ret;
952 if (pending_ret)
953 return pending_ret;
954 return 0;
955
956 }
957
958 int btrfs_write_dirty_block_groups(struct btrfs_trans_handle *trans,
959 struct btrfs_root *root)
960 {
961 struct extent_io_tree *block_group_cache;
962 struct btrfs_block_group_cache *cache;
963 int ret;
964 int err = 0;
965 int werr = 0;
966 struct btrfs_path *path;
967 u64 last = 0;
968 u64 start;
969 u64 end;
970 u64 ptr;
971
972 block_group_cache = &root->fs_info->block_group_cache;
973 path = btrfs_alloc_path();
974 if (!path)
975 return -ENOMEM;
976
977 while(1) {
978 ret = find_first_extent_bit(block_group_cache, last,
979 &start, &end, BLOCK_GROUP_DIRTY);
980 if (ret)
981 break;
982
983 last = end + 1;
984 ret = get_state_private(block_group_cache, start, &ptr);
985 if (ret)
986 break;
987
988 cache = (struct btrfs_block_group_cache *)(unsigned long)ptr;
989 err = write_one_cache_group(trans, root,
990 path, cache);
991 /*
992 * if we fail to write the cache group, we want
993 * to keep it marked dirty in hopes that a later
994 * write will work
995 */
996 if (err) {
997 werr = err;
998 continue;
999 }
1000 clear_extent_bits(block_group_cache, start, end,
1001 BLOCK_GROUP_DIRTY, GFP_NOFS);
1002 }
1003 btrfs_free_path(path);
1004 return werr;
1005 }
1006
1007 static int update_block_group(struct btrfs_trans_handle *trans,
1008 struct btrfs_root *root,
1009 u64 bytenr, u64 num_bytes, int alloc,
1010 int mark_free, int data)
1011 {
1012 struct btrfs_block_group_cache *cache;
1013 struct btrfs_fs_info *info = root->fs_info;
1014 u64 total = num_bytes;
1015 u64 old_val;
1016 u64 byte_in_group;
1017 u64 start;
1018 u64 end;
1019
1020 while(total) {
1021 cache = btrfs_lookup_block_group(info, bytenr);
1022 if (!cache) {
1023 return -1;
1024 }
1025 byte_in_group = bytenr - cache->key.objectid;
1026 WARN_ON(byte_in_group > cache->key.offset);
1027 start = cache->key.objectid;
1028 end = start + cache->key.offset - 1;
1029 set_extent_bits(&info->block_group_cache, start, end,
1030 BLOCK_GROUP_DIRTY, GFP_NOFS);
1031
1032 old_val = btrfs_block_group_used(&cache->item);
1033 num_bytes = min(total, cache->key.offset - byte_in_group);
1034 if (alloc) {
1035 if (cache->data != data &&
1036 old_val < (cache->key.offset >> 1)) {
1037 int bit_to_clear;
1038 int bit_to_set;
1039 cache->data = data;
1040 if (data) {
1041 bit_to_clear = BLOCK_GROUP_METADATA;
1042 bit_to_set = BLOCK_GROUP_DATA;
1043 cache->item.flags &=
1044 ~BTRFS_BLOCK_GROUP_MIXED;
1045 cache->item.flags |=
1046 BTRFS_BLOCK_GROUP_DATA;
1047 } else {
1048 bit_to_clear = BLOCK_GROUP_DATA;
1049 bit_to_set = BLOCK_GROUP_METADATA;
1050 cache->item.flags &=
1051 ~BTRFS_BLOCK_GROUP_MIXED;
1052 cache->item.flags &=
1053 ~BTRFS_BLOCK_GROUP_DATA;
1054 }
1055 clear_extent_bits(&info->block_group_cache,
1056 start, end, bit_to_clear,
1057 GFP_NOFS);
1058 set_extent_bits(&info->block_group_cache,
1059 start, end, bit_to_set,
1060 GFP_NOFS);
1061 } else if (cache->data != data &&
1062 cache->data != BTRFS_BLOCK_GROUP_MIXED) {
1063 cache->data = BTRFS_BLOCK_GROUP_MIXED;
1064 set_extent_bits(&info->block_group_cache,
1065 start, end,
1066 BLOCK_GROUP_DATA |
1067 BLOCK_GROUP_METADATA,
1068 GFP_NOFS);
1069 }
1070 old_val += num_bytes;
1071 } else {
1072 old_val -= num_bytes;
1073 if (mark_free) {
1074 set_extent_dirty(&info->free_space_cache,
1075 bytenr, bytenr + num_bytes - 1,
1076 GFP_NOFS);
1077 }
1078 }
1079 btrfs_set_block_group_used(&cache->item, old_val);
1080 total -= num_bytes;
1081 bytenr += num_bytes;
1082 }
1083 return 0;
1084 }
1085 static int update_pinned_extents(struct btrfs_root *root,
1086 u64 bytenr, u64 num, int pin)
1087 {
1088 u64 len;
1089 struct btrfs_block_group_cache *cache;
1090 struct btrfs_fs_info *fs_info = root->fs_info;
1091
1092 if (pin) {
1093 set_extent_dirty(&fs_info->pinned_extents,
1094 bytenr, bytenr + num - 1, GFP_NOFS);
1095 } else {
1096 clear_extent_dirty(&fs_info->pinned_extents,
1097 bytenr, bytenr + num - 1, GFP_NOFS);
1098 }
1099 while (num > 0) {
1100 cache = btrfs_lookup_block_group(fs_info, bytenr);
1101 WARN_ON(!cache);
1102 len = min(num, cache->key.offset -
1103 (bytenr - cache->key.objectid));
1104 if (pin) {
1105 cache->pinned += len;
1106 fs_info->total_pinned += len;
1107 } else {
1108 cache->pinned -= len;
1109 fs_info->total_pinned -= len;
1110 }
1111 bytenr += len;
1112 num -= len;
1113 }
1114 return 0;
1115 }
1116
1117 int btrfs_copy_pinned(struct btrfs_root *root, struct extent_io_tree *copy)
1118 {
1119 u64 last = 0;
1120 u64 start;
1121 u64 end;
1122 struct extent_io_tree *pinned_extents = &root->fs_info->pinned_extents;
1123 int ret;
1124
1125 while(1) {
1126 ret = find_first_extent_bit(pinned_extents, last,
1127 &start, &end, EXTENT_DIRTY);
1128 if (ret)
1129 break;
1130 set_extent_dirty(copy, start, end, GFP_NOFS);
1131 last = end + 1;
1132 }
1133 return 0;
1134 }
1135
1136 int btrfs_finish_extent_commit(struct btrfs_trans_handle *trans,
1137 struct btrfs_root *root,
1138 struct extent_io_tree *unpin)
1139 {
1140 u64 start;
1141 u64 end;
1142 int ret;
1143 struct extent_io_tree *free_space_cache;
1144 free_space_cache = &root->fs_info->free_space_cache;
1145
1146 while(1) {
1147 ret = find_first_extent_bit(unpin, 0, &start, &end,
1148 EXTENT_DIRTY);
1149 if (ret)
1150 break;
1151 update_pinned_extents(root, start, end + 1 - start, 0);
1152 clear_extent_dirty(unpin, start, end, GFP_NOFS);
1153 set_extent_dirty(free_space_cache, start, end, GFP_NOFS);
1154 }
1155 return 0;
1156 }
1157
1158 static int finish_current_insert(struct btrfs_trans_handle *trans,
1159 struct btrfs_root *extent_root)
1160 {
1161 u64 start;
1162 u64 end;
1163 struct btrfs_fs_info *info = extent_root->fs_info;
1164 struct extent_buffer *eb;
1165 struct btrfs_path *path;
1166 struct btrfs_key ins;
1167 struct btrfs_disk_key first;
1168 struct btrfs_extent_item extent_item;
1169 int ret;
1170 int level;
1171 int err = 0;
1172
1173 btrfs_set_stack_extent_refs(&extent_item, 1);
1174 btrfs_set_key_type(&ins, BTRFS_EXTENT_ITEM_KEY);
1175 path = btrfs_alloc_path();
1176
1177 while(1) {
1178 ret = find_first_extent_bit(&info->extent_ins, 0, &start,
1179 &end, EXTENT_LOCKED);
1180 if (ret)
1181 break;
1182
1183 ins.objectid = start;
1184 ins.offset = end + 1 - start;
1185 err = btrfs_insert_item(trans, extent_root, &ins,
1186 &extent_item, sizeof(extent_item));
1187 clear_extent_bits(&info->extent_ins, start, end, EXTENT_LOCKED,
1188 GFP_NOFS);
1189 eb = read_tree_block(extent_root, ins.objectid, ins.offset);
1190 level = btrfs_header_level(eb);
1191 if (level == 0) {
1192 btrfs_item_key(eb, &first, 0);
1193 } else {
1194 btrfs_node_key(eb, &first, 0);
1195 }
1196 err = btrfs_insert_extent_backref(trans, extent_root, path,
1197 start, extent_root->root_key.objectid,
1198 0, level,
1199 btrfs_disk_key_objectid(&first));
1200 BUG_ON(err);
1201 free_extent_buffer(eb);
1202 }
1203 btrfs_free_path(path);
1204 return 0;
1205 }
1206
1207 static int pin_down_bytes(struct btrfs_root *root, u64 bytenr, u32 num_bytes,
1208 int pending)
1209 {
1210 int err = 0;
1211 struct extent_buffer *buf;
1212
1213 if (!pending) {
1214 buf = btrfs_find_tree_block(root, bytenr, num_bytes);
1215 if (buf) {
1216 if (btrfs_buffer_uptodate(buf)) {
1217 u64 transid =
1218 root->fs_info->running_transaction->transid;
1219 u64 header_transid =
1220 btrfs_header_generation(buf);
1221 if (header_transid == transid) {
1222 clean_tree_block(NULL, root, buf);
1223 free_extent_buffer(buf);
1224 return 1;
1225 }
1226 }
1227 free_extent_buffer(buf);
1228 }
1229 update_pinned_extents(root, bytenr, num_bytes, 1);
1230 } else {
1231 set_extent_bits(&root->fs_info->pending_del,
1232 bytenr, bytenr + num_bytes - 1,
1233 EXTENT_LOCKED, GFP_NOFS);
1234 }
1235 BUG_ON(err < 0);
1236 return 0;
1237 }
1238
1239 /*
1240 * remove an extent from the root, returns 0 on success
1241 */
1242 static int __free_extent(struct btrfs_trans_handle *trans, struct btrfs_root
1243 *root, u64 bytenr, u64 num_bytes,
1244 u64 root_objectid, u64 ref_generation,
1245 u64 owner_objectid, u64 owner_offset, int pin,
1246 int mark_free)
1247 {
1248 struct btrfs_path *path;
1249 struct btrfs_key key;
1250 struct btrfs_fs_info *info = root->fs_info;
1251 struct btrfs_root *extent_root = info->extent_root;
1252 struct extent_buffer *leaf;
1253 int ret;
1254 struct btrfs_extent_item *ei;
1255 u32 refs;
1256
1257 key.objectid = bytenr;
1258 btrfs_set_key_type(&key, BTRFS_EXTENT_ITEM_KEY);
1259 key.offset = num_bytes;
1260 path = btrfs_alloc_path();
1261 if (!path)
1262 return -ENOMEM;
1263
1264 path->reada = 0;
1265 ret = lookup_extent_backref(trans, extent_root, path,
1266 bytenr, root_objectid,
1267 ref_generation,
1268 owner_objectid, owner_offset, 1);
1269 if (ret == 0) {
1270 ret = btrfs_del_item(trans, extent_root, path);
1271 } else {
1272 btrfs_print_leaf(extent_root, path->nodes[0]);
1273 WARN_ON(1);
1274 printk("Unable to find ref byte nr %Lu root %Lu "
1275 " gen %Lu owner %Lu offset %Lu\n", bytenr,
1276 root_objectid, ref_generation, owner_objectid,
1277 owner_offset);
1278 }
1279 btrfs_release_path(extent_root, path);
1280 ret = btrfs_search_slot(trans, extent_root, &key, path, -1, 1);
1281 if (ret < 0)
1282 return ret;
1283 BUG_ON(ret);
1284
1285 leaf = path->nodes[0];
1286 ei = btrfs_item_ptr(leaf, path->slots[0],
1287 struct btrfs_extent_item);
1288 refs = btrfs_extent_refs(leaf, ei);
1289 BUG_ON(refs == 0);
1290 refs -= 1;
1291 btrfs_set_extent_refs(leaf, ei, refs);
1292 btrfs_mark_buffer_dirty(leaf);
1293
1294 if (refs == 0) {
1295 u64 super_used;
1296 u64 root_used;
1297
1298 if (pin) {
1299 ret = pin_down_bytes(root, bytenr, num_bytes, 0);
1300 if (ret > 0)
1301 mark_free = 1;
1302 BUG_ON(ret < 0);
1303 }
1304
1305 /* block accounting for super block */
1306 super_used = btrfs_super_bytes_used(&info->super_copy);
1307 btrfs_set_super_bytes_used(&info->super_copy,
1308 super_used - num_bytes);
1309
1310 /* block accounting for root item */
1311 root_used = btrfs_root_used(&root->root_item);
1312 btrfs_set_root_used(&root->root_item,
1313 root_used - num_bytes);
1314
1315 ret = btrfs_del_item(trans, extent_root, path);
1316 if (ret) {
1317 return ret;
1318 }
1319 ret = update_block_group(trans, root, bytenr, num_bytes, 0,
1320 mark_free, 0);
1321 BUG_ON(ret);
1322 }
1323 btrfs_free_path(path);
1324 finish_current_insert(trans, extent_root);
1325 return ret;
1326 }
1327
1328 /*
1329 * find all the blocks marked as pending in the radix tree and remove
1330 * them from the extent map
1331 */
1332 static int del_pending_extents(struct btrfs_trans_handle *trans, struct
1333 btrfs_root *extent_root)
1334 {
1335 int ret;
1336 int err = 0;
1337 u64 start;
1338 u64 end;
1339 struct extent_io_tree *pending_del;
1340 struct extent_io_tree *pinned_extents;
1341
1342 pending_del = &extent_root->fs_info->pending_del;
1343 pinned_extents = &extent_root->fs_info->pinned_extents;
1344
1345 while(1) {
1346 ret = find_first_extent_bit(pending_del, 0, &start, &end,
1347 EXTENT_LOCKED);
1348 if (ret)
1349 break;
1350 update_pinned_extents(extent_root, start, end + 1 - start, 1);
1351 clear_extent_bits(pending_del, start, end, EXTENT_LOCKED,
1352 GFP_NOFS);
1353 ret = __free_extent(trans, extent_root,
1354 start, end + 1 - start,
1355 extent_root->root_key.objectid,
1356 0, 0, 0, 0, 0);
1357 if (ret)
1358 err = ret;
1359 }
1360 return err;
1361 }
1362
1363 /*
1364 * remove an extent from the root, returns 0 on success
1365 */
1366 int btrfs_free_extent(struct btrfs_trans_handle *trans, struct btrfs_root
1367 *root, u64 bytenr, u64 num_bytes,
1368 u64 root_objectid, u64 ref_generation,
1369 u64 owner_objectid, u64 owner_offset, int pin)
1370 {
1371 struct btrfs_root *extent_root = root->fs_info->extent_root;
1372 int pending_ret;
1373 int ret;
1374
1375 WARN_ON(num_bytes < root->sectorsize);
1376 if (!root->ref_cows)
1377 ref_generation = 0;
1378
1379 if (root == extent_root) {
1380 pin_down_bytes(root, bytenr, num_bytes, 1);
1381 return 0;
1382 }
1383 ret = __free_extent(trans, root, bytenr, num_bytes, root_objectid,
1384 ref_generation, owner_objectid, owner_offset,
1385 pin, pin == 0);
1386 pending_ret = del_pending_extents(trans, root->fs_info->extent_root);
1387 return ret ? ret : pending_ret;
1388 }
1389
1390 static u64 stripe_align(struct btrfs_root *root, u64 val)
1391 {
1392 u64 mask = ((u64)root->stripesize - 1);
1393 u64 ret = (val + mask) & ~mask;
1394 return ret;
1395 }
1396
1397 /*
1398 * walks the btree of allocated extents and find a hole of a given size.
1399 * The key ins is changed to record the hole:
1400 * ins->objectid == block start
1401 * ins->flags = BTRFS_EXTENT_ITEM_KEY
1402 * ins->offset == number of blocks
1403 * Any available blocks before search_start are skipped.
1404 */
1405 static int noinline find_free_extent(struct btrfs_trans_handle *trans,
1406 struct btrfs_root *orig_root,
1407 u64 num_bytes, u64 empty_size,
1408 u64 search_start, u64 search_end,
1409 u64 hint_byte, struct btrfs_key *ins,
1410 u64 exclude_start, u64 exclude_nr,
1411 int data)
1412 {
1413 struct btrfs_path *path;
1414 struct btrfs_key key;
1415 u64 hole_size = 0;
1416 u64 aligned;
1417 int ret;
1418 int slot = 0;
1419 u64 last_byte = 0;
1420 u64 *last_ptr = NULL;
1421 u64 orig_search_start = search_start;
1422 int start_found;
1423 struct extent_buffer *l;
1424 struct btrfs_root * root = orig_root->fs_info->extent_root;
1425 struct btrfs_fs_info *info = root->fs_info;
1426 u64 total_needed = num_bytes;
1427 int level;
1428 struct btrfs_block_group_cache *block_group;
1429 int full_scan = 0;
1430 int wrapped = 0;
1431 int empty_cluster;
1432 u64 cached_start;
1433
1434 WARN_ON(num_bytes < root->sectorsize);
1435 btrfs_set_key_type(ins, BTRFS_EXTENT_ITEM_KEY);
1436
1437 level = btrfs_header_level(root->node);
1438
1439 if (num_bytes >= 32 * 1024 * 1024 && hint_byte) {
1440 data = BTRFS_BLOCK_GROUP_MIXED;
1441 }
1442
1443 if (!data) {
1444 last_ptr = &root->fs_info->last_alloc;
1445 empty_cluster = 128 * 1024;
1446 }
1447
1448 if (data && btrfs_test_opt(root, SSD)) {
1449 last_ptr = &root->fs_info->last_data_alloc;
1450 empty_cluster = 2 * 1024 * 1024;
1451 }
1452
1453 if (last_ptr) {
1454 if (*last_ptr)
1455 hint_byte = *last_ptr;
1456 else {
1457 hint_byte = hint_byte &
1458 ~((u64)BTRFS_BLOCK_GROUP_SIZE - 1);
1459 empty_size += empty_cluster;
1460 }
1461 search_start = max(search_start, hint_byte);
1462 }
1463
1464 search_end = min(search_end,
1465 btrfs_super_total_bytes(&info->super_copy));
1466 if (hint_byte) {
1467 block_group = btrfs_lookup_block_group(info, hint_byte);
1468 if (!block_group)
1469 hint_byte = search_start;
1470 block_group = btrfs_find_block_group(root, block_group,
1471 hint_byte, data, 1);
1472 } else {
1473 block_group = btrfs_find_block_group(root,
1474 trans->block_group,
1475 search_start, data, 1);
1476 }
1477
1478 total_needed += empty_size;
1479 path = btrfs_alloc_path();
1480 check_failed:
1481 if (!block_group) {
1482 block_group = btrfs_lookup_block_group(info, search_start);
1483 if (!block_group)
1484 block_group = btrfs_lookup_block_group(info,
1485 orig_search_start);
1486 }
1487 search_start = find_search_start(root, &block_group, search_start,
1488 total_needed, data);
1489
1490 if (last_ptr && *last_ptr && search_start != *last_ptr) {
1491 *last_ptr = 0;
1492 if (!empty_size) {
1493 empty_size += empty_cluster;
1494 total_needed += empty_size;
1495 }
1496 search_start = find_search_start(root, &block_group,
1497 search_start, total_needed,
1498 data);
1499 }
1500
1501 search_start = stripe_align(root, search_start);
1502 cached_start = search_start;
1503 btrfs_init_path(path);
1504 ins->objectid = search_start;
1505 ins->offset = 0;
1506 start_found = 0;
1507 path->reada = 2;
1508
1509 ret = btrfs_search_slot(trans, root, ins, path, 0, 0);
1510 if (ret < 0)
1511 goto error;
1512 ret = find_previous_extent(root, path);
1513 if (ret < 0)
1514 goto error;
1515 l = path->nodes[0];
1516 btrfs_item_key_to_cpu(l, &key, path->slots[0]);
1517 while (1) {
1518 l = path->nodes[0];
1519 slot = path->slots[0];
1520 if (slot >= btrfs_header_nritems(l)) {
1521 ret = btrfs_next_leaf(root, path);
1522 if (ret == 0)
1523 continue;
1524 if (ret < 0)
1525 goto error;
1526
1527 search_start = max(search_start,
1528 block_group->key.objectid);
1529 if (!start_found) {
1530 aligned = stripe_align(root, search_start);
1531 ins->objectid = aligned;
1532 if (aligned >= search_end) {
1533 ret = -ENOSPC;
1534 goto error;
1535 }
1536 ins->offset = search_end - aligned;
1537 start_found = 1;
1538 goto check_pending;
1539 }
1540 ins->objectid = stripe_align(root,
1541 last_byte > search_start ?
1542 last_byte : search_start);
1543 if (search_end <= ins->objectid) {
1544 ret = -ENOSPC;
1545 goto error;
1546 }
1547 ins->offset = search_end - ins->objectid;
1548 BUG_ON(ins->objectid >= search_end);
1549 goto check_pending;
1550 }
1551 btrfs_item_key_to_cpu(l, &key, slot);
1552
1553 if (key.objectid >= search_start && key.objectid > last_byte &&
1554 start_found) {
1555 if (last_byte < search_start)
1556 last_byte = search_start;
1557 aligned = stripe_align(root, last_byte);
1558 hole_size = key.objectid - aligned;
1559 if (key.objectid > aligned && hole_size >= num_bytes) {
1560 ins->objectid = aligned;
1561 ins->offset = hole_size;
1562 goto check_pending;
1563 }
1564 }
1565 if (btrfs_key_type(&key) != BTRFS_EXTENT_ITEM_KEY) {
1566 if (!start_found && btrfs_key_type(&key) ==
1567 BTRFS_BLOCK_GROUP_ITEM_KEY) {
1568 last_byte = key.objectid;
1569 start_found = 1;
1570 }
1571 goto next;
1572 }
1573
1574
1575 start_found = 1;
1576 last_byte = key.objectid + key.offset;
1577
1578 if (!full_scan && data != BTRFS_BLOCK_GROUP_MIXED &&
1579 last_byte >= block_group->key.objectid +
1580 block_group->key.offset) {
1581 btrfs_release_path(root, path);
1582 search_start = block_group->key.objectid +
1583 block_group->key.offset;
1584 goto new_group;
1585 }
1586 next:
1587 path->slots[0]++;
1588 cond_resched();
1589 }
1590 check_pending:
1591 /* we have to make sure we didn't find an extent that has already
1592 * been allocated by the map tree or the original allocation
1593 */
1594 btrfs_release_path(root, path);
1595 BUG_ON(ins->objectid < search_start);
1596
1597 if (ins->objectid + num_bytes >= search_end)
1598 goto enospc;
1599 if (!full_scan && data != BTRFS_BLOCK_GROUP_MIXED &&
1600 ins->objectid + num_bytes > block_group->
1601 key.objectid + block_group->key.offset) {
1602 search_start = block_group->key.objectid +
1603 block_group->key.offset;
1604 goto new_group;
1605 }
1606 if (test_range_bit(&info->extent_ins, ins->objectid,
1607 ins->objectid + num_bytes -1, EXTENT_LOCKED, 0)) {
1608 search_start = ins->objectid + num_bytes;
1609 goto new_group;
1610 }
1611 if (test_range_bit(&info->pinned_extents, ins->objectid,
1612 ins->objectid + num_bytes -1, EXTENT_DIRTY, 0)) {
1613 search_start = ins->objectid + num_bytes;
1614 goto new_group;
1615 }
1616 if (exclude_nr > 0 && (ins->objectid + num_bytes > exclude_start &&
1617 ins->objectid < exclude_start + exclude_nr)) {
1618 search_start = exclude_start + exclude_nr;
1619 goto new_group;
1620 }
1621 if (!data) {
1622 block_group = btrfs_lookup_block_group(info, ins->objectid);
1623 if (block_group)
1624 trans->block_group = block_group;
1625 }
1626 ins->offset = num_bytes;
1627 btrfs_free_path(path);
1628 if (last_ptr) {
1629 *last_ptr = ins->objectid + ins->offset;
1630 if (*last_ptr ==
1631 btrfs_super_total_bytes(&root->fs_info->super_copy)) {
1632 *last_ptr = 0;
1633 }
1634 }
1635 return 0;
1636
1637 new_group:
1638 if (search_start + num_bytes >= search_end) {
1639 enospc:
1640 search_start = orig_search_start;
1641 if (full_scan) {
1642 ret = -ENOSPC;
1643 goto error;
1644 }
1645 if (wrapped) {
1646 if (!full_scan)
1647 total_needed -= empty_size;
1648 full_scan = 1;
1649 data = BTRFS_BLOCK_GROUP_MIXED;
1650 } else
1651 wrapped = 1;
1652 }
1653 block_group = btrfs_lookup_block_group(info, search_start);
1654 cond_resched();
1655 block_group = btrfs_find_block_group(root, block_group,
1656 search_start, data, 0);
1657 goto check_failed;
1658
1659 error:
1660 btrfs_release_path(root, path);
1661 btrfs_free_path(path);
1662 return ret;
1663 }
1664 /*
1665 * finds a free extent and does all the dirty work required for allocation
1666 * returns the key for the extent through ins, and a tree buffer for
1667 * the first block of the extent through buf.
1668 *
1669 * returns 0 if everything worked, non-zero otherwise.
1670 */
1671 int btrfs_alloc_extent(struct btrfs_trans_handle *trans,
1672 struct btrfs_root *root,
1673 u64 num_bytes, u64 root_objectid, u64 ref_generation,
1674 u64 owner, u64 owner_offset,
1675 u64 empty_size, u64 hint_byte,
1676 u64 search_end, struct btrfs_key *ins, int data)
1677 {
1678 int ret;
1679 int pending_ret;
1680 u64 super_used;
1681 u64 root_used;
1682 u64 search_start = 0;
1683 u64 new_hint;
1684 u32 sizes[2];
1685 struct btrfs_fs_info *info = root->fs_info;
1686 struct btrfs_root *extent_root = info->extent_root;
1687 struct btrfs_extent_item *extent_item;
1688 struct btrfs_extent_ref *ref;
1689 struct btrfs_path *path;
1690 struct btrfs_key keys[2];
1691
1692 new_hint = max(hint_byte, root->fs_info->alloc_start);
1693 if (new_hint < btrfs_super_total_bytes(&info->super_copy))
1694 hint_byte = new_hint;
1695
1696 WARN_ON(num_bytes < root->sectorsize);
1697 ret = find_free_extent(trans, root, num_bytes, empty_size,
1698 search_start, search_end, hint_byte, ins,
1699 trans->alloc_exclude_start,
1700 trans->alloc_exclude_nr, data);
1701 BUG_ON(ret);
1702 if (ret)
1703 return ret;
1704
1705 /* block accounting for super block */
1706 super_used = btrfs_super_bytes_used(&info->super_copy);
1707 btrfs_set_super_bytes_used(&info->super_copy, super_used + num_bytes);
1708
1709 /* block accounting for root item */
1710 root_used = btrfs_root_used(&root->root_item);
1711 btrfs_set_root_used(&root->root_item, root_used + num_bytes);
1712
1713 clear_extent_dirty(&root->fs_info->free_space_cache,
1714 ins->objectid, ins->objectid + ins->offset - 1,
1715 GFP_NOFS);
1716
1717 if (root == extent_root) {
1718 set_extent_bits(&root->fs_info->extent_ins, ins->objectid,
1719 ins->objectid + ins->offset - 1,
1720 EXTENT_LOCKED, GFP_NOFS);
1721 WARN_ON(data == 1);
1722 goto update_block;
1723 }
1724
1725 WARN_ON(trans->alloc_exclude_nr);
1726 trans->alloc_exclude_start = ins->objectid;
1727 trans->alloc_exclude_nr = ins->offset;
1728
1729 memcpy(&keys[0], ins, sizeof(*ins));
1730 keys[1].offset = hash_extent_ref(root_objectid, ref_generation,
1731 owner, owner_offset);
1732 keys[1].objectid = ins->objectid;
1733 keys[1].type = BTRFS_EXTENT_REF_KEY;
1734 sizes[0] = sizeof(*extent_item);
1735 sizes[1] = sizeof(*ref);
1736
1737 path = btrfs_alloc_path();
1738 BUG_ON(!path);
1739
1740 ret = btrfs_insert_empty_items(trans, extent_root, path, keys,
1741 sizes, 2);
1742
1743 BUG_ON(ret);
1744 extent_item = btrfs_item_ptr(path->nodes[0], path->slots[0],
1745 struct btrfs_extent_item);
1746 btrfs_set_extent_refs(path->nodes[0], extent_item, 1);
1747 ref = btrfs_item_ptr(path->nodes[0], path->slots[0] + 1,
1748 struct btrfs_extent_ref);
1749
1750 btrfs_set_ref_root(path->nodes[0], ref, root_objectid);
1751 btrfs_set_ref_generation(path->nodes[0], ref, ref_generation);
1752 btrfs_set_ref_objectid(path->nodes[0], ref, owner);
1753 btrfs_set_ref_offset(path->nodes[0], ref, owner_offset);
1754
1755 btrfs_mark_buffer_dirty(path->nodes[0]);
1756
1757 trans->alloc_exclude_start = 0;
1758 trans->alloc_exclude_nr = 0;
1759 btrfs_free_path(path);
1760 finish_current_insert(trans, extent_root);
1761 pending_ret = del_pending_extents(trans, extent_root);
1762
1763 if (ret) {
1764 return ret;
1765 }
1766 if (pending_ret) {
1767 return pending_ret;
1768 }
1769
1770 update_block:
1771 ret = update_block_group(trans, root, ins->objectid, ins->offset, 1, 0,
1772 data);
1773 if (ret) {
1774 printk("update block group failed for %Lu %Lu\n",
1775 ins->objectid, ins->offset);
1776 BUG();
1777 }
1778 return 0;
1779 }
1780
1781 /*
1782 * helper function to allocate a block for a given tree
1783 * returns the tree buffer or NULL.
1784 */
1785 struct extent_buffer *btrfs_alloc_free_block(struct btrfs_trans_handle *trans,
1786 struct btrfs_root *root,
1787 u32 blocksize,
1788 u64 root_objectid, u64 hint,
1789 u64 empty_size)
1790 {
1791 u64 ref_generation;
1792
1793 if (root->ref_cows)
1794 ref_generation = trans->transid;
1795 else
1796 ref_generation = 0;
1797
1798
1799 return __btrfs_alloc_free_block(trans, root, blocksize, root_objectid,
1800 ref_generation, 0, 0, hint, empty_size);
1801 }
1802
1803 /*
1804 * helper function to allocate a block for a given tree
1805 * returns the tree buffer or NULL.
1806 */
1807 struct extent_buffer *__btrfs_alloc_free_block(struct btrfs_trans_handle *trans,
1808 struct btrfs_root *root,
1809 u32 blocksize,
1810 u64 root_objectid,
1811 u64 ref_generation,
1812 u64 first_objectid,
1813 int level,
1814 u64 hint,
1815 u64 empty_size)
1816 {
1817 struct btrfs_key ins;
1818 int ret;
1819 struct extent_buffer *buf;
1820
1821 ret = btrfs_alloc_extent(trans, root, blocksize,
1822 root_objectid, ref_generation,
1823 level, first_objectid, empty_size, hint,
1824 (u64)-1, &ins, 0);
1825 if (ret) {
1826 BUG_ON(ret > 0);
1827 return ERR_PTR(ret);
1828 }
1829 buf = btrfs_find_create_tree_block(root, ins.objectid, blocksize);
1830 if (!buf) {
1831 btrfs_free_extent(trans, root, ins.objectid, blocksize,
1832 root->root_key.objectid, ref_generation,
1833 0, 0, 0);
1834 return ERR_PTR(-ENOMEM);
1835 }
1836 btrfs_set_header_generation(buf, trans->transid);
1837 clean_tree_block(trans, root, buf);
1838 wait_on_tree_block_writeback(root, buf);
1839 btrfs_set_buffer_uptodate(buf);
1840
1841 if (PageDirty(buf->first_page)) {
1842 printk("page %lu dirty\n", buf->first_page->index);
1843 WARN_ON(1);
1844 }
1845
1846 set_extent_dirty(&trans->transaction->dirty_pages, buf->start,
1847 buf->start + buf->len - 1, GFP_NOFS);
1848 set_extent_bits(&BTRFS_I(root->fs_info->btree_inode)->io_tree,
1849 buf->start, buf->start + buf->len - 1,
1850 EXTENT_CSUM, GFP_NOFS);
1851 buf->flags |= EXTENT_CSUM;
1852 if (!btrfs_test_opt(root, SSD))
1853 btrfs_set_buffer_defrag(buf);
1854 trans->blocks_used++;
1855 return buf;
1856 }
1857
1858 static int noinline drop_leaf_ref(struct btrfs_trans_handle *trans,
1859 struct btrfs_root *root,
1860 struct extent_buffer *leaf)
1861 {
1862 u64 leaf_owner;
1863 u64 leaf_generation;
1864 struct btrfs_key key;
1865 struct btrfs_file_extent_item *fi;
1866 int i;
1867 int nritems;
1868 int ret;
1869
1870 BUG_ON(!btrfs_is_leaf(leaf));
1871 nritems = btrfs_header_nritems(leaf);
1872 leaf_owner = btrfs_header_owner(leaf);
1873 leaf_generation = btrfs_header_generation(leaf);
1874
1875 for (i = 0; i < nritems; i++) {
1876 u64 disk_bytenr;
1877
1878 btrfs_item_key_to_cpu(leaf, &key, i);
1879 if (btrfs_key_type(&key) != BTRFS_EXTENT_DATA_KEY)
1880 continue;
1881 fi = btrfs_item_ptr(leaf, i, struct btrfs_file_extent_item);
1882 if (btrfs_file_extent_type(leaf, fi) ==
1883 BTRFS_FILE_EXTENT_INLINE)
1884 continue;
1885 /*
1886 * FIXME make sure to insert a trans record that
1887 * repeats the snapshot del on crash
1888 */
1889 disk_bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
1890 if (disk_bytenr == 0)
1891 continue;
1892 ret = btrfs_free_extent(trans, root, disk_bytenr,
1893 btrfs_file_extent_disk_num_bytes(leaf, fi),
1894 leaf_owner, leaf_generation,
1895 key.objectid, key.offset, 0);
1896 BUG_ON(ret);
1897 }
1898 return 0;
1899 }
1900
1901 static void noinline reada_walk_down(struct btrfs_root *root,
1902 struct extent_buffer *node,
1903 int slot)
1904 {
1905 u64 bytenr;
1906 u64 last = 0;
1907 u32 nritems;
1908 u32 refs;
1909 u32 blocksize;
1910 int ret;
1911 int i;
1912 int level;
1913 int skipped = 0;
1914
1915 nritems = btrfs_header_nritems(node);
1916 level = btrfs_header_level(node);
1917 if (level)
1918 return;
1919
1920 for (i = slot; i < nritems && skipped < 32; i++) {
1921 bytenr = btrfs_node_blockptr(node, i);
1922 if (last && ((bytenr > last && bytenr - last > 32 * 1024) ||
1923 (last > bytenr && last - bytenr > 32 * 1024))) {
1924 skipped++;
1925 continue;
1926 }
1927 blocksize = btrfs_level_size(root, level - 1);
1928 if (i != slot) {
1929 ret = lookup_extent_ref(NULL, root, bytenr,
1930 blocksize, &refs);
1931 BUG_ON(ret);
1932 if (refs != 1) {
1933 skipped++;
1934 continue;
1935 }
1936 }
1937 mutex_unlock(&root->fs_info->fs_mutex);
1938 ret = readahead_tree_block(root, bytenr, blocksize);
1939 last = bytenr + blocksize;
1940 cond_resched();
1941 mutex_lock(&root->fs_info->fs_mutex);
1942 if (ret)
1943 break;
1944 }
1945 }
1946
1947 /*
1948 * helper function for drop_snapshot, this walks down the tree dropping ref
1949 * counts as it goes.
1950 */
1951 static int noinline walk_down_tree(struct btrfs_trans_handle *trans,
1952 struct btrfs_root *root,
1953 struct btrfs_path *path, int *level)
1954 {
1955 u64 root_owner;
1956 u64 root_gen;
1957 u64 bytenr;
1958 struct extent_buffer *next;
1959 struct extent_buffer *cur;
1960 struct extent_buffer *parent;
1961 u32 blocksize;
1962 int ret;
1963 u32 refs;
1964
1965 WARN_ON(*level < 0);
1966 WARN_ON(*level >= BTRFS_MAX_LEVEL);
1967 ret = lookup_extent_ref(trans, root,
1968 path->nodes[*level]->start,
1969 path->nodes[*level]->len, &refs);
1970 BUG_ON(ret);
1971 if (refs > 1)
1972 goto out;
1973
1974 /*
1975 * walk down to the last node level and free all the leaves
1976 */
1977 while(*level >= 0) {
1978 WARN_ON(*level < 0);
1979 WARN_ON(*level >= BTRFS_MAX_LEVEL);
1980 cur = path->nodes[*level];
1981
1982 if (btrfs_header_level(cur) != *level)
1983 WARN_ON(1);
1984
1985 if (path->slots[*level] >=
1986 btrfs_header_nritems(cur))
1987 break;
1988 if (*level == 0) {
1989 ret = drop_leaf_ref(trans, root, cur);
1990 BUG_ON(ret);
1991 break;
1992 }
1993 bytenr = btrfs_node_blockptr(cur, path->slots[*level]);
1994 blocksize = btrfs_level_size(root, *level - 1);
1995 ret = lookup_extent_ref(trans, root, bytenr, blocksize, &refs);
1996 BUG_ON(ret);
1997 if (refs != 1) {
1998 parent = path->nodes[*level];
1999 root_owner = btrfs_header_owner(parent);
2000 root_gen = btrfs_header_generation(parent);
2001 path->slots[*level]++;
2002 ret = btrfs_free_extent(trans, root, bytenr,
2003 blocksize, root_owner,
2004 root_gen, 0, 0, 1);
2005 BUG_ON(ret);
2006 continue;
2007 }
2008 next = btrfs_find_tree_block(root, bytenr, blocksize);
2009 if (!next || !btrfs_buffer_uptodate(next)) {
2010 free_extent_buffer(next);
2011 reada_walk_down(root, cur, path->slots[*level]);
2012 mutex_unlock(&root->fs_info->fs_mutex);
2013 next = read_tree_block(root, bytenr, blocksize);
2014 mutex_lock(&root->fs_info->fs_mutex);
2015
2016 /* we dropped the lock, check one more time */
2017 ret = lookup_extent_ref(trans, root, bytenr,
2018 blocksize, &refs);
2019 BUG_ON(ret);
2020 if (refs != 1) {
2021 parent = path->nodes[*level];
2022 root_owner = btrfs_header_owner(parent);
2023 root_gen = btrfs_header_generation(parent);
2024
2025 path->slots[*level]++;
2026 free_extent_buffer(next);
2027 ret = btrfs_free_extent(trans, root, bytenr,
2028 blocksize,
2029 root_owner,
2030 root_gen, 0, 0, 1);
2031 BUG_ON(ret);
2032 continue;
2033 }
2034 }
2035 WARN_ON(*level <= 0);
2036 if (path->nodes[*level-1])
2037 free_extent_buffer(path->nodes[*level-1]);
2038 path->nodes[*level-1] = next;
2039 *level = btrfs_header_level(next);
2040 path->slots[*level] = 0;
2041 }
2042 out:
2043 WARN_ON(*level < 0);
2044 WARN_ON(*level >= BTRFS_MAX_LEVEL);
2045
2046 if (path->nodes[*level] == root->node) {
2047 root_owner = root->root_key.objectid;
2048 parent = path->nodes[*level];
2049 } else {
2050 parent = path->nodes[*level + 1];
2051 root_owner = btrfs_header_owner(parent);
2052 }
2053
2054 root_gen = btrfs_header_generation(parent);
2055 ret = btrfs_free_extent(trans, root, path->nodes[*level]->start,
2056 path->nodes[*level]->len,
2057 root_owner, root_gen, 0, 0, 1);
2058 free_extent_buffer(path->nodes[*level]);
2059 path->nodes[*level] = NULL;
2060 *level += 1;
2061 BUG_ON(ret);
2062 return 0;
2063 }
2064
2065 /*
2066 * helper for dropping snapshots. This walks back up the tree in the path
2067 * to find the first node higher up where we haven't yet gone through
2068 * all the slots
2069 */
2070 static int noinline walk_up_tree(struct btrfs_trans_handle *trans,
2071 struct btrfs_root *root,
2072 struct btrfs_path *path, int *level)
2073 {
2074 u64 root_owner;
2075 u64 root_gen;
2076 struct btrfs_root_item *root_item = &root->root_item;
2077 int i;
2078 int slot;
2079 int ret;
2080
2081 for(i = *level; i < BTRFS_MAX_LEVEL - 1 && path->nodes[i]; i++) {
2082 slot = path->slots[i];
2083 if (slot < btrfs_header_nritems(path->nodes[i]) - 1) {
2084 struct extent_buffer *node;
2085 struct btrfs_disk_key disk_key;
2086 node = path->nodes[i];
2087 path->slots[i]++;
2088 *level = i;
2089 WARN_ON(*level == 0);
2090 btrfs_node_key(node, &disk_key, path->slots[i]);
2091 memcpy(&root_item->drop_progress,
2092 &disk_key, sizeof(disk_key));
2093 root_item->drop_level = i;
2094 return 0;
2095 } else {
2096 if (path->nodes[*level] == root->node) {
2097 root_owner = root->root_key.objectid;
2098 root_gen =
2099 btrfs_header_generation(path->nodes[*level]);
2100 } else {
2101 struct extent_buffer *node;
2102 node = path->nodes[*level + 1];
2103 root_owner = btrfs_header_owner(node);
2104 root_gen = btrfs_header_generation(node);
2105 }
2106 ret = btrfs_free_extent(trans, root,
2107 path->nodes[*level]->start,
2108 path->nodes[*level]->len,
2109 root_owner, root_gen, 0, 0, 1);
2110 BUG_ON(ret);
2111 free_extent_buffer(path->nodes[*level]);
2112 path->nodes[*level] = NULL;
2113 *level = i + 1;
2114 }
2115 }
2116 return 1;
2117 }
2118
2119 /*
2120 * drop the reference count on the tree rooted at 'snap'. This traverses
2121 * the tree freeing any blocks that have a ref count of zero after being
2122 * decremented.
2123 */
2124 int btrfs_drop_snapshot(struct btrfs_trans_handle *trans, struct btrfs_root
2125 *root)
2126 {
2127 int ret = 0;
2128 int wret;
2129 int level;
2130 struct btrfs_path *path;
2131 int i;
2132 int orig_level;
2133 struct btrfs_root_item *root_item = &root->root_item;
2134
2135 path = btrfs_alloc_path();
2136 BUG_ON(!path);
2137
2138 level = btrfs_header_level(root->node);
2139 orig_level = level;
2140 if (btrfs_disk_key_objectid(&root_item->drop_progress) == 0) {
2141 path->nodes[level] = root->node;
2142 extent_buffer_get(root->node);
2143 path->slots[level] = 0;
2144 } else {
2145 struct btrfs_key key;
2146 struct btrfs_disk_key found_key;
2147 struct extent_buffer *node;
2148
2149 btrfs_disk_key_to_cpu(&key, &root_item->drop_progress);
2150 level = root_item->drop_level;
2151 path->lowest_level = level;
2152 wret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
2153 if (wret < 0) {
2154 ret = wret;
2155 goto out;
2156 }
2157 node = path->nodes[level];
2158 btrfs_node_key(node, &found_key, path->slots[level]);
2159 WARN_ON(memcmp(&found_key, &root_item->drop_progress,
2160 sizeof(found_key)));
2161 }
2162 while(1) {
2163 wret = walk_down_tree(trans, root, path, &level);
2164 if (wret > 0)
2165 break;
2166 if (wret < 0)
2167 ret = wret;
2168
2169 wret = walk_up_tree(trans, root, path, &level);
2170 if (wret > 0)
2171 break;
2172 if (wret < 0)
2173 ret = wret;
2174 ret = -EAGAIN;
2175 break;
2176 }
2177 for (i = 0; i <= orig_level; i++) {
2178 if (path->nodes[i]) {
2179 free_extent_buffer(path->nodes[i]);
2180 path->nodes[i] = NULL;
2181 }
2182 }
2183 out:
2184 btrfs_free_path(path);
2185 return ret;
2186 }
2187
2188 int btrfs_free_block_groups(struct btrfs_fs_info *info)
2189 {
2190 u64 start;
2191 u64 end;
2192 u64 ptr;
2193 int ret;
2194 while(1) {
2195 ret = find_first_extent_bit(&info->block_group_cache, 0,
2196 &start, &end, (unsigned int)-1);
2197 if (ret)
2198 break;
2199 ret = get_state_private(&info->block_group_cache, start, &ptr);
2200 if (!ret)
2201 kfree((void *)(unsigned long)ptr);
2202 clear_extent_bits(&info->block_group_cache, start,
2203 end, (unsigned int)-1, GFP_NOFS);
2204 }
2205 while(1) {
2206 ret = find_first_extent_bit(&info->free_space_cache, 0,
2207 &start, &end, EXTENT_DIRTY);
2208 if (ret)
2209 break;
2210 clear_extent_dirty(&info->free_space_cache, start,
2211 end, GFP_NOFS);
2212 }
2213 return 0;
2214 }
2215
2216 static int noinline relocate_inode_pages(struct inode *inode, u64 start,
2217 u64 len)
2218 {
2219 u64 page_start;
2220 u64 page_end;
2221 u64 delalloc_start;
2222 u64 existing_delalloc;
2223 unsigned long last_index;
2224 unsigned long i;
2225 struct page *page;
2226 struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
2227 struct file_ra_state *ra;
2228
2229 ra = kzalloc(sizeof(*ra), GFP_NOFS);
2230
2231 mutex_lock(&inode->i_mutex);
2232 i = start >> PAGE_CACHE_SHIFT;
2233 last_index = (start + len - 1) >> PAGE_CACHE_SHIFT;
2234
2235 file_ra_state_init(ra, inode->i_mapping);
2236 btrfs_force_ra(inode->i_mapping, ra, NULL, i, last_index);
2237 kfree(ra);
2238
2239 for (; i <= last_index; i++) {
2240 page = grab_cache_page(inode->i_mapping, i);
2241 if (!page)
2242 goto out_unlock;
2243 if (!PageUptodate(page)) {
2244 btrfs_readpage(NULL, page);
2245 lock_page(page);
2246 if (!PageUptodate(page)) {
2247 unlock_page(page);
2248 page_cache_release(page);
2249 goto out_unlock;
2250 }
2251 }
2252 page_start = (u64)page->index << PAGE_CACHE_SHIFT;
2253 page_end = page_start + PAGE_CACHE_SIZE - 1;
2254
2255 lock_extent(io_tree, page_start, page_end, GFP_NOFS);
2256
2257 delalloc_start = page_start;
2258 existing_delalloc = count_range_bits(io_tree,
2259 &delalloc_start, page_end,
2260 PAGE_CACHE_SIZE, EXTENT_DELALLOC);
2261
2262 set_extent_delalloc(io_tree, page_start,
2263 page_end, GFP_NOFS);
2264
2265 unlock_extent(io_tree, page_start, page_end, GFP_NOFS);
2266 set_page_dirty(page);
2267 unlock_page(page);
2268 page_cache_release(page);
2269 }
2270
2271 out_unlock:
2272 mutex_unlock(&inode->i_mutex);
2273 return 0;
2274 }
2275
2276 /*
2277 * note, this releases the path
2278 */
2279 static int noinline relocate_one_reference(struct btrfs_root *extent_root,
2280 struct btrfs_path *path,
2281 struct btrfs_key *extent_key)
2282 {
2283 struct inode *inode;
2284 struct btrfs_root *found_root;
2285 struct btrfs_key *root_location;
2286 struct btrfs_extent_ref *ref;
2287 u64 ref_root;
2288 u64 ref_gen;
2289 u64 ref_objectid;
2290 u64 ref_offset;
2291 int ret;
2292
2293 ref = btrfs_item_ptr(path->nodes[0], path->slots[0],
2294 struct btrfs_extent_ref);
2295 ref_root = btrfs_ref_root(path->nodes[0], ref);
2296 ref_gen = btrfs_ref_generation(path->nodes[0], ref);
2297 ref_objectid = btrfs_ref_objectid(path->nodes[0], ref);
2298 ref_offset = btrfs_ref_offset(path->nodes[0], ref);
2299 btrfs_release_path(extent_root, path);
2300
2301 root_location = kmalloc(sizeof(*root_location), GFP_NOFS);
2302 root_location->objectid = ref_root;
2303 if (ref_gen == 0)
2304 root_location->offset = 0;
2305 else
2306 root_location->offset = (u64)-1;
2307 root_location->type = BTRFS_ROOT_ITEM_KEY;
2308
2309 found_root = btrfs_read_fs_root_no_name(extent_root->fs_info,
2310 root_location);
2311 BUG_ON(!found_root);
2312 kfree(root_location);
2313
2314 if (ref_objectid >= BTRFS_FIRST_FREE_OBJECTID) {
2315 mutex_unlock(&extent_root->fs_info->fs_mutex);
2316 inode = btrfs_iget_locked(extent_root->fs_info->sb,
2317 ref_objectid, found_root);
2318 if (inode->i_state & I_NEW) {
2319 /* the inode and parent dir are two different roots */
2320 BTRFS_I(inode)->root = found_root;
2321 BTRFS_I(inode)->location.objectid = ref_objectid;
2322 BTRFS_I(inode)->location.type = BTRFS_INODE_ITEM_KEY;
2323 BTRFS_I(inode)->location.offset = 0;
2324 btrfs_read_locked_inode(inode);
2325 unlock_new_inode(inode);
2326
2327 }
2328 /* this can happen if the reference is not against
2329 * the latest version of the tree root
2330 */
2331 if (is_bad_inode(inode)) {
2332 mutex_lock(&extent_root->fs_info->fs_mutex);
2333 goto out;
2334 }
2335 relocate_inode_pages(inode, ref_offset, extent_key->offset);
2336 /* FIXME, data=ordered will help get rid of this */
2337 filemap_fdatawrite(inode->i_mapping);
2338 iput(inode);
2339 mutex_lock(&extent_root->fs_info->fs_mutex);
2340 } else {
2341 struct btrfs_trans_handle *trans;
2342 struct btrfs_key found_key;
2343 struct extent_buffer *eb;
2344 int level;
2345 int i;
2346
2347 trans = btrfs_start_transaction(found_root, 1);
2348 eb = read_tree_block(found_root, extent_key->objectid,
2349 extent_key->offset);
2350 level = btrfs_header_level(eb);
2351
2352 if (level == 0)
2353 btrfs_item_key_to_cpu(eb, &found_key, 0);
2354 else
2355 btrfs_node_key_to_cpu(eb, &found_key, 0);
2356
2357 free_extent_buffer(eb);
2358
2359 path->lowest_level = level;
2360 path->reada = 2;
2361 ret = btrfs_search_slot(trans, found_root, &found_key, path,
2362 0, 1);
2363 path->lowest_level = 0;
2364 for (i = level; i < BTRFS_MAX_LEVEL; i++) {
2365 if (!path->nodes[i])
2366 break;
2367 free_extent_buffer(path->nodes[i]);
2368 path->nodes[i] = NULL;
2369 }
2370 btrfs_release_path(found_root, path);
2371 btrfs_end_transaction(trans, found_root);
2372 }
2373
2374 out:
2375 return 0;
2376 }
2377
2378 static int noinline relocate_one_extent(struct btrfs_root *extent_root,
2379 struct btrfs_path *path,
2380 struct btrfs_key *extent_key)
2381 {
2382 struct btrfs_key key;
2383 struct btrfs_key found_key;
2384 struct extent_buffer *leaf;
2385 u32 nritems;
2386 u32 item_size;
2387 int ret = 0;
2388
2389 key.objectid = extent_key->objectid;
2390 key.type = BTRFS_EXTENT_REF_KEY;
2391 key.offset = 0;
2392
2393 while(1) {
2394 ret = btrfs_search_slot(NULL, extent_root, &key, path, 0, 0);
2395
2396 if (ret < 0)
2397 goto out;
2398
2399 ret = 0;
2400 leaf = path->nodes[0];
2401 nritems = btrfs_header_nritems(leaf);
2402 if (path->slots[0] == nritems)
2403 goto out;
2404
2405 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
2406 if (found_key.objectid != extent_key->objectid)
2407 break;
2408
2409 if (found_key.type != BTRFS_EXTENT_REF_KEY)
2410 break;
2411
2412 key.offset = found_key.offset + 1;
2413 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
2414
2415 ret = relocate_one_reference(extent_root, path, extent_key);
2416 if (ret)
2417 goto out;
2418 }
2419 ret = 0;
2420 out:
2421 btrfs_release_path(extent_root, path);
2422 return ret;
2423 }
2424
2425 int btrfs_shrink_extent_tree(struct btrfs_root *root, u64 new_size)
2426 {
2427 struct btrfs_trans_handle *trans;
2428 struct btrfs_root *tree_root = root->fs_info->tree_root;
2429 struct btrfs_path *path;
2430 u64 cur_byte;
2431 u64 total_found;
2432 struct btrfs_fs_info *info = root->fs_info;
2433 struct extent_io_tree *block_group_cache;
2434 struct btrfs_key key;
2435 struct btrfs_key found_key;
2436 struct extent_buffer *leaf;
2437 u32 nritems;
2438 int ret;
2439 int progress = 0;
2440
2441 btrfs_set_super_total_bytes(&info->super_copy, new_size);
2442 clear_extent_dirty(&info->free_space_cache, new_size, (u64)-1,
2443 GFP_NOFS);
2444 block_group_cache = &info->block_group_cache;
2445 path = btrfs_alloc_path();
2446 root = root->fs_info->extent_root;
2447 path->reada = 2;
2448
2449 again:
2450 total_found = 0;
2451 key.objectid = new_size;
2452 key.offset = 0;
2453 key.type = 0;
2454 cur_byte = key.objectid;
2455
2456 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
2457 if (ret < 0)
2458 goto out;
2459
2460 ret = find_previous_extent(root, path);
2461 if (ret < 0)
2462 goto out;
2463 if (ret == 0) {
2464 leaf = path->nodes[0];
2465 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
2466 if (found_key.objectid + found_key.offset > new_size) {
2467 cur_byte = found_key.objectid;
2468 key.objectid = cur_byte;
2469 }
2470 }
2471 btrfs_release_path(root, path);
2472
2473 while(1) {
2474 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
2475 if (ret < 0)
2476 goto out;
2477
2478 leaf = path->nodes[0];
2479 nritems = btrfs_header_nritems(leaf);
2480 next:
2481 if (path->slots[0] >= nritems) {
2482 ret = btrfs_next_leaf(root, path);
2483 if (ret < 0)
2484 goto out;
2485 if (ret == 1) {
2486 ret = 0;
2487 break;
2488 }
2489 leaf = path->nodes[0];
2490 nritems = btrfs_header_nritems(leaf);
2491 }
2492
2493 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
2494
2495 if (progress && need_resched()) {
2496 memcpy(&key, &found_key, sizeof(key));
2497 mutex_unlock(&root->fs_info->fs_mutex);
2498 cond_resched();
2499 mutex_lock(&root->fs_info->fs_mutex);
2500 btrfs_release_path(root, path);
2501 btrfs_search_slot(NULL, root, &key, path, 0, 0);
2502 progress = 0;
2503 goto next;
2504 }
2505 progress = 1;
2506
2507 if (btrfs_key_type(&found_key) != BTRFS_EXTENT_ITEM_KEY ||
2508 found_key.objectid + found_key.offset <= cur_byte) {
2509 path->slots[0]++;
2510 goto next;
2511 }
2512
2513 total_found++;
2514 cur_byte = found_key.objectid + found_key.offset;
2515 key.objectid = cur_byte;
2516 btrfs_release_path(root, path);
2517 ret = relocate_one_extent(root, path, &found_key);
2518 }
2519
2520 btrfs_release_path(root, path);
2521
2522 if (total_found > 0) {
2523 trans = btrfs_start_transaction(tree_root, 1);
2524 btrfs_commit_transaction(trans, tree_root);
2525
2526 mutex_unlock(&root->fs_info->fs_mutex);
2527 btrfs_clean_old_snapshots(tree_root);
2528 mutex_lock(&root->fs_info->fs_mutex);
2529
2530 trans = btrfs_start_transaction(tree_root, 1);
2531 btrfs_commit_transaction(trans, tree_root);
2532 goto again;
2533 }
2534
2535 trans = btrfs_start_transaction(root, 1);
2536 key.objectid = new_size;
2537 key.offset = 0;
2538 key.type = 0;
2539 while(1) {
2540 u64 ptr;
2541
2542 ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
2543 if (ret < 0)
2544 goto out;
2545
2546 leaf = path->nodes[0];
2547 nritems = btrfs_header_nritems(leaf);
2548 bg_next:
2549 if (path->slots[0] >= nritems) {
2550 ret = btrfs_next_leaf(root, path);
2551 if (ret < 0)
2552 break;
2553 if (ret == 1) {
2554 ret = 0;
2555 break;
2556 }
2557 leaf = path->nodes[0];
2558 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
2559
2560 /*
2561 * btrfs_next_leaf doesn't cow buffers, we have to
2562 * do the search again
2563 */
2564 memcpy(&key, &found_key, sizeof(key));
2565 btrfs_release_path(root, path);
2566 goto resched_check;
2567 }
2568
2569 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
2570 if (btrfs_key_type(&found_key) != BTRFS_BLOCK_GROUP_ITEM_KEY) {
2571 printk("shrinker found key %Lu %u %Lu\n",
2572 found_key.objectid, found_key.type,
2573 found_key.offset);
2574 path->slots[0]++;
2575 goto bg_next;
2576 }
2577 ret = get_state_private(&info->block_group_cache,
2578 found_key.objectid, &ptr);
2579 if (!ret)
2580 kfree((void *)(unsigned long)ptr);
2581
2582 clear_extent_bits(&info->block_group_cache, found_key.objectid,
2583 found_key.objectid + found_key.offset - 1,
2584 (unsigned int)-1, GFP_NOFS);
2585
2586 key.objectid = found_key.objectid + 1;
2587 btrfs_del_item(trans, root, path);
2588 btrfs_release_path(root, path);
2589 resched_check:
2590 if (need_resched()) {
2591 mutex_unlock(&root->fs_info->fs_mutex);
2592 cond_resched();
2593 mutex_lock(&root->fs_info->fs_mutex);
2594 }
2595 }
2596 clear_extent_dirty(&info->free_space_cache, new_size, (u64)-1,
2597 GFP_NOFS);
2598 btrfs_commit_transaction(trans, root);
2599 out:
2600 btrfs_free_path(path);
2601 return ret;
2602 }
2603
2604 int btrfs_grow_extent_tree(struct btrfs_trans_handle *trans,
2605 struct btrfs_root *root, u64 new_size)
2606 {
2607 struct btrfs_path *path;
2608 u64 nr = 0;
2609 u64 cur_byte;
2610 u64 old_size;
2611 unsigned long rem;
2612 struct btrfs_block_group_cache *cache;
2613 struct btrfs_block_group_item *item;
2614 struct btrfs_fs_info *info = root->fs_info;
2615 struct extent_io_tree *block_group_cache;
2616 struct btrfs_key key;
2617 struct extent_buffer *leaf;
2618 int ret;
2619 int bit;
2620
2621 old_size = btrfs_super_total_bytes(&info->super_copy);
2622 block_group_cache = &info->block_group_cache;
2623
2624 root = info->extent_root;
2625
2626 cache = btrfs_lookup_block_group(root->fs_info, old_size - 1);
2627
2628 cur_byte = cache->key.objectid + cache->key.offset;
2629 if (cur_byte >= new_size)
2630 goto set_size;
2631
2632 key.offset = BTRFS_BLOCK_GROUP_SIZE;
2633 btrfs_set_key_type(&key, BTRFS_BLOCK_GROUP_ITEM_KEY);
2634
2635 path = btrfs_alloc_path();
2636 if (!path)
2637 return -ENOMEM;
2638
2639 while(cur_byte < new_size) {
2640 key.objectid = cur_byte;
2641 ret = btrfs_insert_empty_item(trans, root, path, &key,
2642 sizeof(struct btrfs_block_group_item));
2643 BUG_ON(ret);
2644 leaf = path->nodes[0];
2645 item = btrfs_item_ptr(leaf, path->slots[0],
2646 struct btrfs_block_group_item);
2647
2648 btrfs_set_disk_block_group_used(leaf, item, 0);
2649 div_long_long_rem(nr, 3, &rem);
2650 if (rem) {
2651 btrfs_set_disk_block_group_flags(leaf, item,
2652 BTRFS_BLOCK_GROUP_DATA);
2653 } else {
2654 btrfs_set_disk_block_group_flags(leaf, item, 0);
2655 }
2656 nr++;
2657
2658 cache = kmalloc(sizeof(*cache), GFP_NOFS);
2659 BUG_ON(!cache);
2660
2661 read_extent_buffer(leaf, &cache->item, (unsigned long)item,
2662 sizeof(cache->item));
2663
2664 memcpy(&cache->key, &key, sizeof(key));
2665 cache->cached = 0;
2666 cache->pinned = 0;
2667 cur_byte = key.objectid + key.offset;
2668 btrfs_release_path(root, path);
2669
2670 if (cache->item.flags & BTRFS_BLOCK_GROUP_DATA) {
2671 bit = BLOCK_GROUP_DATA;
2672 cache->data = BTRFS_BLOCK_GROUP_DATA;
2673 } else {
2674 bit = BLOCK_GROUP_METADATA;
2675 cache->data = 0;
2676 }
2677
2678 /* use EXTENT_LOCKED to prevent merging */
2679 set_extent_bits(block_group_cache, key.objectid,
2680 key.objectid + key.offset - 1,
2681 bit | EXTENT_LOCKED, GFP_NOFS);
2682 set_state_private(block_group_cache, key.objectid,
2683 (unsigned long)cache);
2684 }
2685 btrfs_free_path(path);
2686 set_size:
2687 btrfs_set_super_total_bytes(&info->super_copy, new_size);
2688 return 0;
2689 }
2690
2691 int btrfs_read_block_groups(struct btrfs_root *root)
2692 {
2693 struct btrfs_path *path;
2694 int ret;
2695 int err = 0;
2696 int bit;
2697 struct btrfs_block_group_cache *cache;
2698 struct btrfs_fs_info *info = root->fs_info;
2699 struct extent_io_tree *block_group_cache;
2700 struct btrfs_key key;
2701 struct btrfs_key found_key;
2702 struct extent_buffer *leaf;
2703
2704 block_group_cache = &info->block_group_cache;
2705
2706 root = info->extent_root;
2707 key.objectid = 0;
2708 key.offset = BTRFS_BLOCK_GROUP_SIZE;
2709 btrfs_set_key_type(&key, BTRFS_BLOCK_GROUP_ITEM_KEY);
2710
2711 path = btrfs_alloc_path();
2712 if (!path)
2713 return -ENOMEM;
2714
2715 while(1) {
2716 ret = btrfs_search_slot(NULL, info->extent_root,
2717 &key, path, 0, 0);
2718 if (ret != 0) {
2719 err = ret;
2720 break;
2721 }
2722 leaf = path->nodes[0];
2723 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
2724 cache = kmalloc(sizeof(*cache), GFP_NOFS);
2725 if (!cache) {
2726 err = -1;
2727 break;
2728 }
2729
2730 read_extent_buffer(leaf, &cache->item,
2731 btrfs_item_ptr_offset(leaf, path->slots[0]),
2732 sizeof(cache->item));
2733 memcpy(&cache->key, &found_key, sizeof(found_key));
2734 cache->cached = 0;
2735 cache->pinned = 0;
2736 key.objectid = found_key.objectid + found_key.offset;
2737 btrfs_release_path(root, path);
2738
2739 if (cache->item.flags & BTRFS_BLOCK_GROUP_MIXED) {
2740 bit = BLOCK_GROUP_DATA | BLOCK_GROUP_METADATA;
2741 cache->data = BTRFS_BLOCK_GROUP_MIXED;
2742 } else if (cache->item.flags & BTRFS_BLOCK_GROUP_DATA) {
2743 bit = BLOCK_GROUP_DATA;
2744 cache->data = BTRFS_BLOCK_GROUP_DATA;
2745 } else {
2746 bit = BLOCK_GROUP_METADATA;
2747 cache->data = 0;
2748 }
2749
2750 /* use EXTENT_LOCKED to prevent merging */
2751 set_extent_bits(block_group_cache, found_key.objectid,
2752 found_key.objectid + found_key.offset - 1,
2753 bit | EXTENT_LOCKED, GFP_NOFS);
2754 set_state_private(block_group_cache, found_key.objectid,
2755 (unsigned long)cache);
2756
2757 if (key.objectid >=
2758 btrfs_super_total_bytes(&info->super_copy))
2759 break;
2760 }
2761
2762 btrfs_free_path(path);
2763 return 0;
2764 }
Linux kernel - Deliverables
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