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Btrfs: free space accounting redo
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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 #include <linux/sched.h>
19 #include <linux/pagemap.h>
20 #include <linux/writeback.h>
21 #include <linux/blkdev.h>
22 #include "hash.h"
23 #include "crc32c.h"
24 #include "ctree.h"
25 #include "disk-io.h"
26 #include "print-tree.h"
27 #include "transaction.h"
28 #include "volumes.h"
29 #include "locking.h"
30 #include "ref-cache.h"
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 struct btrfs_block_group_cache *
37 __btrfs_find_block_group(struct btrfs_root *root,
38 struct btrfs_block_group_cache *hint,
39 u64 search_start, int data, int owner);
40
41 void maybe_lock_mutex(struct btrfs_root *root)
42 {
43 if (root != root->fs_info->extent_root &&
44 root != root->fs_info->chunk_root &&
45 root != root->fs_info->dev_root) {
46 mutex_lock(&root->fs_info->alloc_mutex);
47 }
48 }
49
50 void maybe_unlock_mutex(struct btrfs_root *root)
51 {
52 if (root != root->fs_info->extent_root &&
53 root != root->fs_info->chunk_root &&
54 root != root->fs_info->dev_root) {
55 mutex_unlock(&root->fs_info->alloc_mutex);
56 }
57 }
58
59 static int block_group_bits(struct btrfs_block_group_cache *cache, u64 bits)
60 {
61 return (cache->flags & bits) == bits;
62 }
63
64 /*
65 * this adds the block group to the fs_info rb tree for the block group
66 * cache
67 */
68 int btrfs_add_block_group_cache(struct btrfs_fs_info *info,
69 struct btrfs_block_group_cache *block_group)
70 {
71 struct rb_node **p;
72 struct rb_node *parent = NULL;
73 struct btrfs_block_group_cache *cache;
74
75 spin_lock(&info->block_group_cache_lock);
76 p = &info->block_group_cache_tree.rb_node;
77
78 while (*p) {
79 parent = *p;
80 cache = rb_entry(parent, struct btrfs_block_group_cache,
81 cache_node);
82 if (block_group->key.objectid < cache->key.objectid) {
83 p = &(*p)->rb_left;
84 } else if (block_group->key.objectid > cache->key.objectid) {
85 p = &(*p)->rb_right;
86 } else {
87 spin_unlock(&info->block_group_cache_lock);
88 return -EEXIST;
89 }
90 }
91
92 rb_link_node(&block_group->cache_node, parent, p);
93 rb_insert_color(&block_group->cache_node,
94 &info->block_group_cache_tree);
95 spin_unlock(&info->block_group_cache_lock);
96
97 return 0;
98 }
99
100 /*
101 * This will return the block group at or after bytenr if contains is 0, else
102 * it will return the block group that contains the bytenr
103 */
104 static struct btrfs_block_group_cache *
105 block_group_cache_tree_search(struct btrfs_fs_info *info, u64 bytenr,
106 int contains)
107 {
108 struct btrfs_block_group_cache *cache, *ret = NULL;
109 struct rb_node *n;
110 u64 end, start;
111
112 spin_lock(&info->block_group_cache_lock);
113 n = info->block_group_cache_tree.rb_node;
114
115 while (n) {
116 cache = rb_entry(n, struct btrfs_block_group_cache,
117 cache_node);
118 end = cache->key.objectid + cache->key.offset - 1;
119 start = cache->key.objectid;
120
121 if (bytenr < start) {
122 if (!contains && (!ret || start < ret->key.objectid))
123 ret = cache;
124 n = n->rb_left;
125 } else if (bytenr > start) {
126 if (contains && bytenr <= end) {
127 ret = cache;
128 break;
129 }
130 n = n->rb_right;
131 } else {
132 ret = cache;
133 break;
134 }
135 }
136 spin_unlock(&info->block_group_cache_lock);
137
138 return ret;
139 }
140
141 /*
142 * this is only called by cache_block_group, since we could have freed extents
143 * we need to check the pinned_extents for any extents that can't be used yet
144 * since their free space will be released as soon as the transaction commits.
145 */
146 static int add_new_free_space(struct btrfs_block_group_cache *block_group,
147 struct btrfs_fs_info *info, u64 start, u64 end)
148 {
149 u64 extent_start, extent_end, size;
150 int ret;
151
152 while (start < end) {
153 ret = find_first_extent_bit(&info->pinned_extents, start,
154 &extent_start, &extent_end,
155 EXTENT_DIRTY);
156 if (ret)
157 break;
158
159 if (extent_start == start) {
160 start = extent_end + 1;
161 } else if (extent_start > start && extent_start < end) {
162 size = extent_start - start;
163 ret = btrfs_add_free_space(block_group, start, size);
164 BUG_ON(ret);
165 start = extent_end + 1;
166 } else {
167 break;
168 }
169 }
170
171 if (start < end) {
172 size = end - start;
173 ret = btrfs_add_free_space(block_group, start, size);
174 BUG_ON(ret);
175 }
176
177 return 0;
178 }
179
180 static int cache_block_group(struct btrfs_root *root,
181 struct btrfs_block_group_cache *block_group)
182 {
183 struct btrfs_path *path;
184 int ret = 0;
185 struct btrfs_key key;
186 struct extent_buffer *leaf;
187 int slot;
188 u64 last = 0;
189 u64 first_free;
190 int found = 0;
191
192 if (!block_group)
193 return 0;
194
195 root = root->fs_info->extent_root;
196
197 if (block_group->cached)
198 return 0;
199
200 path = btrfs_alloc_path();
201 if (!path)
202 return -ENOMEM;
203
204 path->reada = 2;
205 /*
206 * we get into deadlocks with paths held by callers of this function.
207 * since the alloc_mutex is protecting things right now, just
208 * skip the locking here
209 */
210 path->skip_locking = 1;
211 first_free = max_t(u64, block_group->key.objectid,
212 BTRFS_SUPER_INFO_OFFSET + BTRFS_SUPER_INFO_SIZE);
213 key.objectid = block_group->key.objectid;
214 key.offset = 0;
215 btrfs_set_key_type(&key, BTRFS_EXTENT_ITEM_KEY);
216 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
217 if (ret < 0)
218 goto err;
219 ret = btrfs_previous_item(root, path, 0, BTRFS_EXTENT_ITEM_KEY);
220 if (ret < 0)
221 goto err;
222 if (ret == 0) {
223 leaf = path->nodes[0];
224 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
225 if (key.objectid + key.offset > first_free)
226 first_free = key.objectid + key.offset;
227 }
228 while(1) {
229 leaf = path->nodes[0];
230 slot = path->slots[0];
231 if (slot >= btrfs_header_nritems(leaf)) {
232 ret = btrfs_next_leaf(root, path);
233 if (ret < 0)
234 goto err;
235 if (ret == 0)
236 continue;
237 else
238 break;
239 }
240 btrfs_item_key_to_cpu(leaf, &key, slot);
241 if (key.objectid < block_group->key.objectid)
242 goto next;
243
244 if (key.objectid >= block_group->key.objectid +
245 block_group->key.offset)
246 break;
247
248 if (btrfs_key_type(&key) == BTRFS_EXTENT_ITEM_KEY) {
249 if (!found) {
250 last = first_free;
251 found = 1;
252 }
253
254 add_new_free_space(block_group, root->fs_info, last,
255 key.objectid);
256
257 last = key.objectid + key.offset;
258 }
259 next:
260 path->slots[0]++;
261 }
262
263 if (!found)
264 last = first_free;
265
266 add_new_free_space(block_group, root->fs_info, last,
267 block_group->key.objectid +
268 block_group->key.offset);
269
270 block_group->cached = 1;
271 ret = 0;
272 err:
273 btrfs_free_path(path);
274 return ret;
275 }
276
277 /*
278 * return the block group that starts at or after bytenr
279 */
280 struct btrfs_block_group_cache *btrfs_lookup_first_block_group(struct
281 btrfs_fs_info *info,
282 u64 bytenr)
283 {
284 struct btrfs_block_group_cache *cache;
285
286 cache = block_group_cache_tree_search(info, bytenr, 0);
287
288 return cache;
289 }
290
291 /*
292 * return the block group that contains teh given bytenr
293 */
294 struct btrfs_block_group_cache *btrfs_lookup_block_group(struct
295 btrfs_fs_info *info,
296 u64 bytenr)
297 {
298 struct btrfs_block_group_cache *cache;
299
300 cache = block_group_cache_tree_search(info, bytenr, 1);
301
302 return cache;
303 }
304
305 static int noinline find_free_space(struct btrfs_root *root,
306 struct btrfs_block_group_cache **cache_ret,
307 u64 *start_ret, u64 num, int data)
308 {
309 int ret;
310 struct btrfs_block_group_cache *cache = *cache_ret;
311 struct btrfs_free_space *info = NULL;
312 u64 last;
313 u64 total_fs_bytes;
314 u64 search_start = *start_ret;
315
316 WARN_ON(!mutex_is_locked(&root->fs_info->alloc_mutex));
317 total_fs_bytes = btrfs_super_total_bytes(&root->fs_info->super_copy);
318
319 if (!cache)
320 goto out;
321
322 last = max(search_start, cache->key.objectid);
323
324 again:
325 ret = cache_block_group(root, cache);
326 if (ret)
327 goto out;
328
329 if (cache->ro || !block_group_bits(cache, data))
330 goto new_group;
331
332 info = btrfs_find_free_space(cache, last, num);
333 if (info) {
334 *start_ret = info->offset;
335 return 0;
336 }
337
338 new_group:
339 last = cache->key.objectid + cache->key.offset;
340
341 cache = btrfs_lookup_first_block_group(root->fs_info, last);
342 if (!cache || cache->key.objectid >= total_fs_bytes)
343 goto out;
344
345 *cache_ret = cache;
346 goto again;
347
348 out:
349 return -ENOSPC;
350 }
351
352 static u64 div_factor(u64 num, int factor)
353 {
354 if (factor == 10)
355 return num;
356 num *= factor;
357 do_div(num, 10);
358 return num;
359 }
360
361 static struct btrfs_space_info *__find_space_info(struct btrfs_fs_info *info,
362 u64 flags)
363 {
364 struct list_head *head = &info->space_info;
365 struct list_head *cur;
366 struct btrfs_space_info *found;
367 list_for_each(cur, head) {
368 found = list_entry(cur, struct btrfs_space_info, list);
369 if (found->flags == flags)
370 return found;
371 }
372 return NULL;
373
374 }
375
376 static struct btrfs_block_group_cache *
377 __btrfs_find_block_group(struct btrfs_root *root,
378 struct btrfs_block_group_cache *hint,
379 u64 search_start, int data, int owner)
380 {
381 struct btrfs_block_group_cache *cache;
382 struct btrfs_block_group_cache *found_group = NULL;
383 struct btrfs_fs_info *info = root->fs_info;
384 struct btrfs_space_info *sinfo;
385 u64 used;
386 u64 last = 0;
387 u64 free_check;
388 int full_search = 0;
389 int factor = 10;
390 int wrapped = 0;
391
392 if (data & BTRFS_BLOCK_GROUP_METADATA)
393 factor = 9;
394
395 if (search_start) {
396 struct btrfs_block_group_cache *shint;
397 shint = btrfs_lookup_first_block_group(info, search_start);
398 if (shint && block_group_bits(shint, data) && !shint->ro) {
399 spin_lock(&shint->lock);
400 used = btrfs_block_group_used(&shint->item);
401 if (used + shint->pinned <
402 div_factor(shint->key.offset, factor)) {
403 spin_unlock(&shint->lock);
404 return shint;
405 }
406 spin_unlock(&shint->lock);
407 }
408 }
409 if (hint && !hint->ro && block_group_bits(hint, data)) {
410 spin_lock(&hint->lock);
411 used = btrfs_block_group_used(&hint->item);
412 if (used + hint->pinned <
413 div_factor(hint->key.offset, factor)) {
414 spin_unlock(&hint->lock);
415 return hint;
416 }
417 spin_unlock(&hint->lock);
418 last = hint->key.objectid + hint->key.offset;
419 } else {
420 if (hint)
421 last = max(hint->key.objectid, search_start);
422 else
423 last = search_start;
424 }
425 sinfo = __find_space_info(root->fs_info, data);
426 if (!sinfo)
427 goto found;
428 again:
429 while(1) {
430 struct list_head *l;
431
432 cache = NULL;
433
434 spin_lock(&sinfo->lock);
435 list_for_each(l, &sinfo->block_groups) {
436 struct btrfs_block_group_cache *entry;
437 entry = list_entry(l, struct btrfs_block_group_cache,
438 list);
439 if ((entry->key.objectid >= last) &&
440 (!cache || (entry->key.objectid <
441 cache->key.objectid)))
442 cache = entry;
443 }
444 spin_unlock(&sinfo->lock);
445
446 if (!cache)
447 break;
448
449 spin_lock(&cache->lock);
450 last = cache->key.objectid + cache->key.offset;
451 used = btrfs_block_group_used(&cache->item);
452
453 if (!cache->ro && block_group_bits(cache, data)) {
454 free_check = div_factor(cache->key.offset, factor);
455 if (used + cache->pinned < free_check) {
456 found_group = cache;
457 spin_unlock(&cache->lock);
458 goto found;
459 }
460 }
461 spin_unlock(&cache->lock);
462 cond_resched();
463 }
464 if (!wrapped) {
465 last = search_start;
466 wrapped = 1;
467 goto again;
468 }
469 if (!full_search && factor < 10) {
470 last = search_start;
471 full_search = 1;
472 factor = 10;
473 goto again;
474 }
475 found:
476 return found_group;
477 }
478
479 struct btrfs_block_group_cache *btrfs_find_block_group(struct btrfs_root *root,
480 struct btrfs_block_group_cache
481 *hint, u64 search_start,
482 int data, int owner)
483 {
484
485 struct btrfs_block_group_cache *ret;
486 ret = __btrfs_find_block_group(root, hint, search_start, data, owner);
487 return ret;
488 }
489
490 static u64 hash_extent_ref(u64 root_objectid, u64 ref_generation,
491 u64 owner, u64 owner_offset)
492 {
493 u32 high_crc = ~(u32)0;
494 u32 low_crc = ~(u32)0;
495 __le64 lenum;
496 lenum = cpu_to_le64(root_objectid);
497 high_crc = btrfs_crc32c(high_crc, &lenum, sizeof(lenum));
498 lenum = cpu_to_le64(ref_generation);
499 low_crc = btrfs_crc32c(low_crc, &lenum, sizeof(lenum));
500 if (owner >= BTRFS_FIRST_FREE_OBJECTID) {
501 lenum = cpu_to_le64(owner);
502 low_crc = btrfs_crc32c(low_crc, &lenum, sizeof(lenum));
503 lenum = cpu_to_le64(owner_offset);
504 low_crc = btrfs_crc32c(low_crc, &lenum, sizeof(lenum));
505 }
506 return ((u64)high_crc << 32) | (u64)low_crc;
507 }
508
509 static int match_extent_ref(struct extent_buffer *leaf,
510 struct btrfs_extent_ref *disk_ref,
511 struct btrfs_extent_ref *cpu_ref)
512 {
513 int ret;
514 int len;
515
516 if (cpu_ref->objectid)
517 len = sizeof(*cpu_ref);
518 else
519 len = 2 * sizeof(u64);
520 ret = memcmp_extent_buffer(leaf, cpu_ref, (unsigned long)disk_ref,
521 len);
522 return ret == 0;
523 }
524
525 /* simple helper to search for an existing extent at a given offset */
526 int btrfs_lookup_extent(struct btrfs_root *root, struct btrfs_path *path,
527 u64 start, u64 len)
528 {
529 int ret;
530 struct btrfs_key key;
531
532 maybe_lock_mutex(root);
533 key.objectid = start;
534 key.offset = len;
535 btrfs_set_key_type(&key, BTRFS_EXTENT_ITEM_KEY);
536 ret = btrfs_search_slot(NULL, root->fs_info->extent_root, &key, path,
537 0, 0);
538 maybe_unlock_mutex(root);
539 return ret;
540 }
541
542 static int noinline lookup_extent_backref(struct btrfs_trans_handle *trans,
543 struct btrfs_root *root,
544 struct btrfs_path *path, u64 bytenr,
545 u64 root_objectid,
546 u64 ref_generation, u64 owner,
547 u64 owner_offset, int del)
548 {
549 u64 hash;
550 struct btrfs_key key;
551 struct btrfs_key found_key;
552 struct btrfs_extent_ref ref;
553 struct extent_buffer *leaf;
554 struct btrfs_extent_ref *disk_ref;
555 int ret;
556 int ret2;
557
558 btrfs_set_stack_ref_root(&ref, root_objectid);
559 btrfs_set_stack_ref_generation(&ref, ref_generation);
560 btrfs_set_stack_ref_objectid(&ref, owner);
561 btrfs_set_stack_ref_offset(&ref, owner_offset);
562
563 hash = hash_extent_ref(root_objectid, ref_generation, owner,
564 owner_offset);
565 key.offset = hash;
566 key.objectid = bytenr;
567 key.type = BTRFS_EXTENT_REF_KEY;
568
569 while (1) {
570 ret = btrfs_search_slot(trans, root, &key, path,
571 del ? -1 : 0, del);
572 if (ret < 0)
573 goto out;
574 leaf = path->nodes[0];
575 if (ret != 0) {
576 u32 nritems = btrfs_header_nritems(leaf);
577 if (path->slots[0] >= nritems) {
578 ret2 = btrfs_next_leaf(root, path);
579 if (ret2)
580 goto out;
581 leaf = path->nodes[0];
582 }
583 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
584 if (found_key.objectid != bytenr ||
585 found_key.type != BTRFS_EXTENT_REF_KEY)
586 goto out;
587 key.offset = found_key.offset;
588 if (del) {
589 btrfs_release_path(root, path);
590 continue;
591 }
592 }
593 disk_ref = btrfs_item_ptr(path->nodes[0],
594 path->slots[0],
595 struct btrfs_extent_ref);
596 if (match_extent_ref(path->nodes[0], disk_ref, &ref)) {
597 ret = 0;
598 goto out;
599 }
600 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
601 key.offset = found_key.offset + 1;
602 btrfs_release_path(root, path);
603 }
604 out:
605 return ret;
606 }
607
608 /*
609 * Back reference rules. Back refs have three main goals:
610 *
611 * 1) differentiate between all holders of references to an extent so that
612 * when a reference is dropped we can make sure it was a valid reference
613 * before freeing the extent.
614 *
615 * 2) Provide enough information to quickly find the holders of an extent
616 * if we notice a given block is corrupted or bad.
617 *
618 * 3) Make it easy to migrate blocks for FS shrinking or storage pool
619 * maintenance. This is actually the same as #2, but with a slightly
620 * different use case.
621 *
622 * File extents can be referenced by:
623 *
624 * - multiple snapshots, subvolumes, or different generations in one subvol
625 * - different files inside a single subvolume (in theory, not implemented yet)
626 * - different offsets inside a file (bookend extents in file.c)
627 *
628 * The extent ref structure has fields for:
629 *
630 * - Objectid of the subvolume root
631 * - Generation number of the tree holding the reference
632 * - objectid of the file holding the reference
633 * - offset in the file corresponding to the key holding the reference
634 *
635 * When a file extent is allocated the fields are filled in:
636 * (root_key.objectid, trans->transid, inode objectid, offset in file)
637 *
638 * When a leaf is cow'd new references are added for every file extent found
639 * in the leaf. It looks the same as the create case, but trans->transid
640 * will be different when the block is cow'd.
641 *
642 * (root_key.objectid, trans->transid, inode objectid, offset in file)
643 *
644 * When a file extent is removed either during snapshot deletion or file
645 * truncation, the corresponding back reference is found
646 * by searching for:
647 *
648 * (btrfs_header_owner(leaf), btrfs_header_generation(leaf),
649 * inode objectid, offset in file)
650 *
651 * Btree extents can be referenced by:
652 *
653 * - Different subvolumes
654 * - Different generations of the same subvolume
655 *
656 * Storing sufficient information for a full reverse mapping of a btree
657 * block would require storing the lowest key of the block in the backref,
658 * and it would require updating that lowest key either before write out or
659 * every time it changed. Instead, the objectid of the lowest key is stored
660 * along with the level of the tree block. This provides a hint
661 * about where in the btree the block can be found. Searches through the
662 * btree only need to look for a pointer to that block, so they stop one
663 * level higher than the level recorded in the backref.
664 *
665 * Some btrees do not do reference counting on their extents. These
666 * include the extent tree and the tree of tree roots. Backrefs for these
667 * trees always have a generation of zero.
668 *
669 * When a tree block is created, back references are inserted:
670 *
671 * (root->root_key.objectid, trans->transid or zero, level, lowest_key_objectid)
672 *
673 * When a tree block is cow'd in a reference counted root,
674 * new back references are added for all the blocks it points to.
675 * These are of the form (trans->transid will have increased since creation):
676 *
677 * (root->root_key.objectid, trans->transid, level, lowest_key_objectid)
678 *
679 * Because the lowest_key_objectid and the level are just hints
680 * they are not used when backrefs are deleted. When a backref is deleted:
681 *
682 * if backref was for a tree root:
683 * root_objectid = root->root_key.objectid
684 * else
685 * root_objectid = btrfs_header_owner(parent)
686 *
687 * (root_objectid, btrfs_header_generation(parent) or zero, 0, 0)
688 *
689 * Back Reference Key hashing:
690 *
691 * Back references have four fields, each 64 bits long. Unfortunately,
692 * This is hashed into a single 64 bit number and placed into the key offset.
693 * The key objectid corresponds to the first byte in the extent, and the
694 * key type is set to BTRFS_EXTENT_REF_KEY
695 */
696 int btrfs_insert_extent_backref(struct btrfs_trans_handle *trans,
697 struct btrfs_root *root,
698 struct btrfs_path *path, u64 bytenr,
699 u64 root_objectid, u64 ref_generation,
700 u64 owner, u64 owner_offset)
701 {
702 u64 hash;
703 struct btrfs_key key;
704 struct btrfs_extent_ref ref;
705 struct btrfs_extent_ref *disk_ref;
706 int ret;
707
708 btrfs_set_stack_ref_root(&ref, root_objectid);
709 btrfs_set_stack_ref_generation(&ref, ref_generation);
710 btrfs_set_stack_ref_objectid(&ref, owner);
711 btrfs_set_stack_ref_offset(&ref, owner_offset);
712
713 hash = hash_extent_ref(root_objectid, ref_generation, owner,
714 owner_offset);
715 key.offset = hash;
716 key.objectid = bytenr;
717 key.type = BTRFS_EXTENT_REF_KEY;
718
719 ret = btrfs_insert_empty_item(trans, root, path, &key, sizeof(ref));
720 while (ret == -EEXIST) {
721 disk_ref = btrfs_item_ptr(path->nodes[0], path->slots[0],
722 struct btrfs_extent_ref);
723 if (match_extent_ref(path->nodes[0], disk_ref, &ref))
724 goto out;
725 key.offset++;
726 btrfs_release_path(root, path);
727 ret = btrfs_insert_empty_item(trans, root, path, &key,
728 sizeof(ref));
729 }
730 if (ret)
731 goto out;
732 disk_ref = btrfs_item_ptr(path->nodes[0], path->slots[0],
733 struct btrfs_extent_ref);
734 write_extent_buffer(path->nodes[0], &ref, (unsigned long)disk_ref,
735 sizeof(ref));
736 btrfs_mark_buffer_dirty(path->nodes[0]);
737 out:
738 btrfs_release_path(root, path);
739 return ret;
740 }
741
742 static int __btrfs_inc_extent_ref(struct btrfs_trans_handle *trans,
743 struct btrfs_root *root,
744 u64 bytenr, u64 num_bytes,
745 u64 root_objectid, u64 ref_generation,
746 u64 owner, u64 owner_offset)
747 {
748 struct btrfs_path *path;
749 int ret;
750 struct btrfs_key key;
751 struct extent_buffer *l;
752 struct btrfs_extent_item *item;
753 u32 refs;
754
755 WARN_ON(num_bytes < root->sectorsize);
756 path = btrfs_alloc_path();
757 if (!path)
758 return -ENOMEM;
759
760 path->reada = 1;
761 key.objectid = bytenr;
762 btrfs_set_key_type(&key, BTRFS_EXTENT_ITEM_KEY);
763 key.offset = num_bytes;
764 ret = btrfs_search_slot(trans, root->fs_info->extent_root, &key, path,
765 0, 1);
766 if (ret < 0)
767 return ret;
768 if (ret != 0) {
769 BUG();
770 }
771 BUG_ON(ret != 0);
772 l = path->nodes[0];
773 item = btrfs_item_ptr(l, path->slots[0], struct btrfs_extent_item);
774 refs = btrfs_extent_refs(l, item);
775 btrfs_set_extent_refs(l, item, refs + 1);
776 btrfs_mark_buffer_dirty(path->nodes[0]);
777
778 btrfs_release_path(root->fs_info->extent_root, path);
779
780 path->reada = 1;
781 ret = btrfs_insert_extent_backref(trans, root->fs_info->extent_root,
782 path, bytenr, root_objectid,
783 ref_generation, owner, owner_offset);
784 BUG_ON(ret);
785 finish_current_insert(trans, root->fs_info->extent_root);
786 del_pending_extents(trans, root->fs_info->extent_root);
787
788 btrfs_free_path(path);
789 return 0;
790 }
791
792 int btrfs_inc_extent_ref(struct btrfs_trans_handle *trans,
793 struct btrfs_root *root,
794 u64 bytenr, u64 num_bytes,
795 u64 root_objectid, u64 ref_generation,
796 u64 owner, u64 owner_offset)
797 {
798 int ret;
799
800 mutex_lock(&root->fs_info->alloc_mutex);
801 ret = __btrfs_inc_extent_ref(trans, root, bytenr, num_bytes,
802 root_objectid, ref_generation,
803 owner, owner_offset);
804 mutex_unlock(&root->fs_info->alloc_mutex);
805 return ret;
806 }
807
808 int btrfs_extent_post_op(struct btrfs_trans_handle *trans,
809 struct btrfs_root *root)
810 {
811 finish_current_insert(trans, root->fs_info->extent_root);
812 del_pending_extents(trans, root->fs_info->extent_root);
813 return 0;
814 }
815
816 static int lookup_extent_ref(struct btrfs_trans_handle *trans,
817 struct btrfs_root *root, u64 bytenr,
818 u64 num_bytes, u32 *refs)
819 {
820 struct btrfs_path *path;
821 int ret;
822 struct btrfs_key key;
823 struct extent_buffer *l;
824 struct btrfs_extent_item *item;
825
826 WARN_ON(num_bytes < root->sectorsize);
827 path = btrfs_alloc_path();
828 path->reada = 1;
829 key.objectid = bytenr;
830 key.offset = num_bytes;
831 btrfs_set_key_type(&key, BTRFS_EXTENT_ITEM_KEY);
832 ret = btrfs_search_slot(trans, root->fs_info->extent_root, &key, path,
833 0, 0);
834 if (ret < 0)
835 goto out;
836 if (ret != 0) {
837 btrfs_print_leaf(root, path->nodes[0]);
838 printk("failed to find block number %Lu\n", bytenr);
839 BUG();
840 }
841 l = path->nodes[0];
842 item = btrfs_item_ptr(l, path->slots[0], struct btrfs_extent_item);
843 *refs = btrfs_extent_refs(l, item);
844 out:
845 btrfs_free_path(path);
846 return 0;
847 }
848
849
850 static int get_reference_status(struct btrfs_root *root, u64 bytenr,
851 u64 parent_gen, u64 ref_objectid,
852 u64 *min_generation, u32 *ref_count)
853 {
854 struct btrfs_root *extent_root = root->fs_info->extent_root;
855 struct btrfs_path *path;
856 struct extent_buffer *leaf;
857 struct btrfs_extent_ref *ref_item;
858 struct btrfs_key key;
859 struct btrfs_key found_key;
860 u64 root_objectid = root->root_key.objectid;
861 u64 ref_generation;
862 u32 nritems;
863 int ret;
864
865 key.objectid = bytenr;
866 key.offset = 0;
867 key.type = BTRFS_EXTENT_ITEM_KEY;
868
869 path = btrfs_alloc_path();
870 mutex_lock(&root->fs_info->alloc_mutex);
871 ret = btrfs_search_slot(NULL, extent_root, &key, path, 0, 0);
872 if (ret < 0)
873 goto out;
874 BUG_ON(ret == 0);
875
876 leaf = path->nodes[0];
877 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
878
879 if (found_key.objectid != bytenr ||
880 found_key.type != BTRFS_EXTENT_ITEM_KEY) {
881 ret = 1;
882 goto out;
883 }
884
885 *ref_count = 0;
886 *min_generation = (u64)-1;
887
888 while (1) {
889 leaf = path->nodes[0];
890 nritems = btrfs_header_nritems(leaf);
891 if (path->slots[0] >= nritems) {
892 ret = btrfs_next_leaf(extent_root, path);
893 if (ret < 0)
894 goto out;
895 if (ret == 0)
896 continue;
897 break;
898 }
899 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
900 if (found_key.objectid != bytenr)
901 break;
902
903 if (found_key.type != BTRFS_EXTENT_REF_KEY) {
904 path->slots[0]++;
905 continue;
906 }
907
908 ref_item = btrfs_item_ptr(leaf, path->slots[0],
909 struct btrfs_extent_ref);
910 ref_generation = btrfs_ref_generation(leaf, ref_item);
911 /*
912 * For (parent_gen > 0 && parent_gen > ref_gen):
913 *
914 * we reach here through the oldest root, therefore
915 * all other reference from same snapshot should have
916 * a larger generation.
917 */
918 if ((root_objectid != btrfs_ref_root(leaf, ref_item)) ||
919 (parent_gen > 0 && parent_gen > ref_generation) ||
920 (ref_objectid >= BTRFS_FIRST_FREE_OBJECTID &&
921 ref_objectid != btrfs_ref_objectid(leaf, ref_item))) {
922 if (ref_count)
923 *ref_count = 2;
924 break;
925 }
926
927 *ref_count = 1;
928 if (*min_generation > ref_generation)
929 *min_generation = ref_generation;
930
931 path->slots[0]++;
932 }
933 ret = 0;
934 out:
935 mutex_unlock(&root->fs_info->alloc_mutex);
936 btrfs_free_path(path);
937 return ret;
938 }
939
940 int btrfs_cross_ref_exists(struct btrfs_trans_handle *trans,
941 struct btrfs_root *root,
942 struct btrfs_key *key, u64 bytenr)
943 {
944 struct btrfs_root *old_root;
945 struct btrfs_path *path = NULL;
946 struct extent_buffer *eb;
947 struct btrfs_file_extent_item *item;
948 u64 ref_generation;
949 u64 min_generation;
950 u64 extent_start;
951 u32 ref_count;
952 int level;
953 int ret;
954
955 BUG_ON(trans == NULL);
956 BUG_ON(key->type != BTRFS_EXTENT_DATA_KEY);
957 ret = get_reference_status(root, bytenr, 0, key->objectid,
958 &min_generation, &ref_count);
959 if (ret)
960 return ret;
961
962 if (ref_count != 1)
963 return 1;
964
965 old_root = root->dirty_root->root;
966 ref_generation = old_root->root_key.offset;
967
968 /* all references are created in running transaction */
969 if (min_generation > ref_generation) {
970 ret = 0;
971 goto out;
972 }
973
974 path = btrfs_alloc_path();
975 if (!path) {
976 ret = -ENOMEM;
977 goto out;
978 }
979
980 path->skip_locking = 1;
981 /* if no item found, the extent is referenced by other snapshot */
982 ret = btrfs_search_slot(NULL, old_root, key, path, 0, 0);
983 if (ret)
984 goto out;
985
986 eb = path->nodes[0];
987 item = btrfs_item_ptr(eb, path->slots[0],
988 struct btrfs_file_extent_item);
989 if (btrfs_file_extent_type(eb, item) != BTRFS_FILE_EXTENT_REG ||
990 btrfs_file_extent_disk_bytenr(eb, item) != bytenr) {
991 ret = 1;
992 goto out;
993 }
994
995 for (level = BTRFS_MAX_LEVEL - 1; level >= -1; level--) {
996 if (level >= 0) {
997 eb = path->nodes[level];
998 if (!eb)
999 continue;
1000 extent_start = eb->start;
1001 } else
1002 extent_start = bytenr;
1003
1004 ret = get_reference_status(root, extent_start, ref_generation,
1005 0, &min_generation, &ref_count);
1006 if (ret)
1007 goto out;
1008
1009 if (ref_count != 1) {
1010 ret = 1;
1011 goto out;
1012 }
1013 if (level >= 0)
1014 ref_generation = btrfs_header_generation(eb);
1015 }
1016 ret = 0;
1017 out:
1018 if (path)
1019 btrfs_free_path(path);
1020 return ret;
1021 }
1022
1023 int btrfs_inc_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root,
1024 struct extent_buffer *buf, int cache_ref)
1025 {
1026 u64 bytenr;
1027 u32 nritems;
1028 struct btrfs_key key;
1029 struct btrfs_file_extent_item *fi;
1030 int i;
1031 int level;
1032 int ret;
1033 int faili;
1034 int nr_file_extents = 0;
1035
1036 if (!root->ref_cows)
1037 return 0;
1038
1039 level = btrfs_header_level(buf);
1040 nritems = btrfs_header_nritems(buf);
1041 for (i = 0; i < nritems; i++) {
1042 cond_resched();
1043 if (level == 0) {
1044 u64 disk_bytenr;
1045 btrfs_item_key_to_cpu(buf, &key, i);
1046 if (btrfs_key_type(&key) != BTRFS_EXTENT_DATA_KEY)
1047 continue;
1048 fi = btrfs_item_ptr(buf, i,
1049 struct btrfs_file_extent_item);
1050 if (btrfs_file_extent_type(buf, fi) ==
1051 BTRFS_FILE_EXTENT_INLINE)
1052 continue;
1053 disk_bytenr = btrfs_file_extent_disk_bytenr(buf, fi);
1054 if (disk_bytenr == 0)
1055 continue;
1056
1057 if (buf != root->commit_root)
1058 nr_file_extents++;
1059
1060 mutex_lock(&root->fs_info->alloc_mutex);
1061 ret = __btrfs_inc_extent_ref(trans, root, disk_bytenr,
1062 btrfs_file_extent_disk_num_bytes(buf, fi),
1063 root->root_key.objectid, trans->transid,
1064 key.objectid, key.offset);
1065 mutex_unlock(&root->fs_info->alloc_mutex);
1066 if (ret) {
1067 faili = i;
1068 WARN_ON(1);
1069 goto fail;
1070 }
1071 } else {
1072 bytenr = btrfs_node_blockptr(buf, i);
1073 btrfs_node_key_to_cpu(buf, &key, i);
1074
1075 mutex_lock(&root->fs_info->alloc_mutex);
1076 ret = __btrfs_inc_extent_ref(trans, root, bytenr,
1077 btrfs_level_size(root, level - 1),
1078 root->root_key.objectid,
1079 trans->transid,
1080 level - 1, key.objectid);
1081 mutex_unlock(&root->fs_info->alloc_mutex);
1082 if (ret) {
1083 faili = i;
1084 WARN_ON(1);
1085 goto fail;
1086 }
1087 }
1088 }
1089 /* cache orignal leaf block's references */
1090 if (level == 0 && cache_ref && buf != root->commit_root) {
1091 struct btrfs_leaf_ref *ref;
1092 struct btrfs_extent_info *info;
1093
1094 ref = btrfs_alloc_leaf_ref(root, nr_file_extents);
1095 if (!ref) {
1096 WARN_ON(1);
1097 goto out;
1098 }
1099
1100 ref->root_gen = root->root_key.offset;
1101 ref->bytenr = buf->start;
1102 ref->owner = btrfs_header_owner(buf);
1103 ref->generation = btrfs_header_generation(buf);
1104 ref->nritems = nr_file_extents;
1105 info = ref->extents;
1106
1107 for (i = 0; nr_file_extents > 0 && i < nritems; i++) {
1108 u64 disk_bytenr;
1109 btrfs_item_key_to_cpu(buf, &key, i);
1110 if (btrfs_key_type(&key) != BTRFS_EXTENT_DATA_KEY)
1111 continue;
1112 fi = btrfs_item_ptr(buf, i,
1113 struct btrfs_file_extent_item);
1114 if (btrfs_file_extent_type(buf, fi) ==
1115 BTRFS_FILE_EXTENT_INLINE)
1116 continue;
1117 disk_bytenr = btrfs_file_extent_disk_bytenr(buf, fi);
1118 if (disk_bytenr == 0)
1119 continue;
1120
1121 info->bytenr = disk_bytenr;
1122 info->num_bytes =
1123 btrfs_file_extent_disk_num_bytes(buf, fi);
1124 info->objectid = key.objectid;
1125 info->offset = key.offset;
1126 info++;
1127 }
1128
1129 BUG_ON(!root->ref_tree);
1130 ret = btrfs_add_leaf_ref(root, ref);
1131 WARN_ON(ret);
1132 btrfs_free_leaf_ref(root, ref);
1133 }
1134 out:
1135 return 0;
1136 fail:
1137 WARN_ON(1);
1138 #if 0
1139 for (i =0; i < faili; i++) {
1140 if (level == 0) {
1141 u64 disk_bytenr;
1142 btrfs_item_key_to_cpu(buf, &key, i);
1143 if (btrfs_key_type(&key) != BTRFS_EXTENT_DATA_KEY)
1144 continue;
1145 fi = btrfs_item_ptr(buf, i,
1146 struct btrfs_file_extent_item);
1147 if (btrfs_file_extent_type(buf, fi) ==
1148 BTRFS_FILE_EXTENT_INLINE)
1149 continue;
1150 disk_bytenr = btrfs_file_extent_disk_bytenr(buf, fi);
1151 if (disk_bytenr == 0)
1152 continue;
1153 err = btrfs_free_extent(trans, root, disk_bytenr,
1154 btrfs_file_extent_disk_num_bytes(buf,
1155 fi), 0);
1156 BUG_ON(err);
1157 } else {
1158 bytenr = btrfs_node_blockptr(buf, i);
1159 err = btrfs_free_extent(trans, root, bytenr,
1160 btrfs_level_size(root, level - 1), 0);
1161 BUG_ON(err);
1162 }
1163 }
1164 #endif
1165 return ret;
1166 }
1167
1168 static int write_one_cache_group(struct btrfs_trans_handle *trans,
1169 struct btrfs_root *root,
1170 struct btrfs_path *path,
1171 struct btrfs_block_group_cache *cache)
1172 {
1173 int ret;
1174 int pending_ret;
1175 struct btrfs_root *extent_root = root->fs_info->extent_root;
1176 unsigned long bi;
1177 struct extent_buffer *leaf;
1178
1179 ret = btrfs_search_slot(trans, extent_root, &cache->key, path, 0, 1);
1180 if (ret < 0)
1181 goto fail;
1182 BUG_ON(ret);
1183
1184 leaf = path->nodes[0];
1185 bi = btrfs_item_ptr_offset(leaf, path->slots[0]);
1186 write_extent_buffer(leaf, &cache->item, bi, sizeof(cache->item));
1187 btrfs_mark_buffer_dirty(leaf);
1188 btrfs_release_path(extent_root, path);
1189 fail:
1190 finish_current_insert(trans, extent_root);
1191 pending_ret = del_pending_extents(trans, extent_root);
1192 if (ret)
1193 return ret;
1194 if (pending_ret)
1195 return pending_ret;
1196 return 0;
1197
1198 }
1199
1200 int btrfs_write_dirty_block_groups(struct btrfs_trans_handle *trans,
1201 struct btrfs_root *root)
1202 {
1203 struct btrfs_block_group_cache *cache, *entry;
1204 struct rb_node *n;
1205 int err = 0;
1206 int werr = 0;
1207 struct btrfs_path *path;
1208 u64 last = 0;
1209
1210 path = btrfs_alloc_path();
1211 if (!path)
1212 return -ENOMEM;
1213
1214 mutex_lock(&root->fs_info->alloc_mutex);
1215 while(1) {
1216 cache = NULL;
1217 spin_lock(&root->fs_info->block_group_cache_lock);
1218 for (n = rb_first(&root->fs_info->block_group_cache_tree);
1219 n; n = rb_next(n)) {
1220 entry = rb_entry(n, struct btrfs_block_group_cache,
1221 cache_node);
1222 if (entry->dirty) {
1223 cache = entry;
1224 break;
1225 }
1226 }
1227 spin_unlock(&root->fs_info->block_group_cache_lock);
1228
1229 if (!cache)
1230 break;
1231
1232 last += cache->key.offset;
1233
1234 err = write_one_cache_group(trans, root,
1235 path, cache);
1236 /*
1237 * if we fail to write the cache group, we want
1238 * to keep it marked dirty in hopes that a later
1239 * write will work
1240 */
1241 if (err) {
1242 werr = err;
1243 continue;
1244 }
1245
1246 cache->dirty = 0;
1247 }
1248 btrfs_free_path(path);
1249 mutex_unlock(&root->fs_info->alloc_mutex);
1250 return werr;
1251 }
1252
1253 static int update_space_info(struct btrfs_fs_info *info, u64 flags,
1254 u64 total_bytes, u64 bytes_used,
1255 struct btrfs_space_info **space_info)
1256 {
1257 struct btrfs_space_info *found;
1258
1259 found = __find_space_info(info, flags);
1260 if (found) {
1261 found->total_bytes += total_bytes;
1262 found->bytes_used += bytes_used;
1263 found->full = 0;
1264 *space_info = found;
1265 return 0;
1266 }
1267 found = kmalloc(sizeof(*found), GFP_NOFS);
1268 if (!found)
1269 return -ENOMEM;
1270
1271 list_add(&found->list, &info->space_info);
1272 INIT_LIST_HEAD(&found->block_groups);
1273 spin_lock_init(&found->lock);
1274 found->flags = flags;
1275 found->total_bytes = total_bytes;
1276 found->bytes_used = bytes_used;
1277 found->bytes_pinned = 0;
1278 found->full = 0;
1279 found->force_alloc = 0;
1280 *space_info = found;
1281 return 0;
1282 }
1283
1284 static void set_avail_alloc_bits(struct btrfs_fs_info *fs_info, u64 flags)
1285 {
1286 u64 extra_flags = flags & (BTRFS_BLOCK_GROUP_RAID0 |
1287 BTRFS_BLOCK_GROUP_RAID1 |
1288 BTRFS_BLOCK_GROUP_RAID10 |
1289 BTRFS_BLOCK_GROUP_DUP);
1290 if (extra_flags) {
1291 if (flags & BTRFS_BLOCK_GROUP_DATA)
1292 fs_info->avail_data_alloc_bits |= extra_flags;
1293 if (flags & BTRFS_BLOCK_GROUP_METADATA)
1294 fs_info->avail_metadata_alloc_bits |= extra_flags;
1295 if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
1296 fs_info->avail_system_alloc_bits |= extra_flags;
1297 }
1298 }
1299
1300 static u64 reduce_alloc_profile(struct btrfs_root *root, u64 flags)
1301 {
1302 u64 num_devices = root->fs_info->fs_devices->num_devices;
1303
1304 if (num_devices == 1)
1305 flags &= ~(BTRFS_BLOCK_GROUP_RAID1 | BTRFS_BLOCK_GROUP_RAID0);
1306 if (num_devices < 4)
1307 flags &= ~BTRFS_BLOCK_GROUP_RAID10;
1308
1309 if ((flags & BTRFS_BLOCK_GROUP_DUP) &&
1310 (flags & (BTRFS_BLOCK_GROUP_RAID1 |
1311 BTRFS_BLOCK_GROUP_RAID10))) {
1312 flags &= ~BTRFS_BLOCK_GROUP_DUP;
1313 }
1314
1315 if ((flags & BTRFS_BLOCK_GROUP_RAID1) &&
1316 (flags & BTRFS_BLOCK_GROUP_RAID10)) {
1317 flags &= ~BTRFS_BLOCK_GROUP_RAID1;
1318 }
1319
1320 if ((flags & BTRFS_BLOCK_GROUP_RAID0) &&
1321 ((flags & BTRFS_BLOCK_GROUP_RAID1) |
1322 (flags & BTRFS_BLOCK_GROUP_RAID10) |
1323 (flags & BTRFS_BLOCK_GROUP_DUP)))
1324 flags &= ~BTRFS_BLOCK_GROUP_RAID0;
1325 return flags;
1326 }
1327
1328 static int do_chunk_alloc(struct btrfs_trans_handle *trans,
1329 struct btrfs_root *extent_root, u64 alloc_bytes,
1330 u64 flags, int force)
1331 {
1332 struct btrfs_space_info *space_info;
1333 u64 thresh;
1334 u64 start;
1335 u64 num_bytes;
1336 int ret = 0;
1337
1338 flags = reduce_alloc_profile(extent_root, flags);
1339
1340 space_info = __find_space_info(extent_root->fs_info, flags);
1341 if (!space_info) {
1342 ret = update_space_info(extent_root->fs_info, flags,
1343 0, 0, &space_info);
1344 BUG_ON(ret);
1345 }
1346 BUG_ON(!space_info);
1347
1348 if (space_info->force_alloc) {
1349 force = 1;
1350 space_info->force_alloc = 0;
1351 }
1352 if (space_info->full)
1353 goto out;
1354
1355 thresh = div_factor(space_info->total_bytes, 6);
1356 if (!force &&
1357 (space_info->bytes_used + space_info->bytes_pinned + alloc_bytes) <
1358 thresh)
1359 goto out;
1360
1361 mutex_lock(&extent_root->fs_info->chunk_mutex);
1362 ret = btrfs_alloc_chunk(trans, extent_root, &start, &num_bytes, flags);
1363 if (ret == -ENOSPC) {
1364 printk("space info full %Lu\n", flags);
1365 space_info->full = 1;
1366 goto out_unlock;
1367 }
1368 BUG_ON(ret);
1369
1370 ret = btrfs_make_block_group(trans, extent_root, 0, flags,
1371 BTRFS_FIRST_CHUNK_TREE_OBJECTID, start, num_bytes);
1372 BUG_ON(ret);
1373
1374 out_unlock:
1375 mutex_unlock(&extent_root->fs_info->chunk_mutex);
1376 out:
1377 return ret;
1378 }
1379
1380 static int update_block_group(struct btrfs_trans_handle *trans,
1381 struct btrfs_root *root,
1382 u64 bytenr, u64 num_bytes, int alloc,
1383 int mark_free)
1384 {
1385 struct btrfs_block_group_cache *cache;
1386 struct btrfs_fs_info *info = root->fs_info;
1387 u64 total = num_bytes;
1388 u64 old_val;
1389 u64 byte_in_group;
1390
1391 WARN_ON(!mutex_is_locked(&root->fs_info->alloc_mutex));
1392 while(total) {
1393 cache = btrfs_lookup_block_group(info, bytenr);
1394 if (!cache) {
1395 return -1;
1396 }
1397 byte_in_group = bytenr - cache->key.objectid;
1398 WARN_ON(byte_in_group > cache->key.offset);
1399
1400 spin_lock(&cache->lock);
1401 cache->dirty = 1;
1402 old_val = btrfs_block_group_used(&cache->item);
1403 num_bytes = min(total, cache->key.offset - byte_in_group);
1404 if (alloc) {
1405 old_val += num_bytes;
1406 cache->space_info->bytes_used += num_bytes;
1407 btrfs_set_block_group_used(&cache->item, old_val);
1408 spin_unlock(&cache->lock);
1409 } else {
1410 old_val -= num_bytes;
1411 cache->space_info->bytes_used -= num_bytes;
1412 btrfs_set_block_group_used(&cache->item, old_val);
1413 spin_unlock(&cache->lock);
1414 if (mark_free) {
1415 int ret;
1416 ret = btrfs_add_free_space(cache, bytenr,
1417 num_bytes);
1418 if (ret)
1419 return -1;
1420 }
1421 }
1422 total -= num_bytes;
1423 bytenr += num_bytes;
1424 }
1425 return 0;
1426 }
1427
1428 static u64 first_logical_byte(struct btrfs_root *root, u64 search_start)
1429 {
1430 struct btrfs_block_group_cache *cache;
1431
1432 cache = btrfs_lookup_first_block_group(root->fs_info, search_start);
1433 if (!cache)
1434 return 0;
1435
1436 return cache->key.objectid;
1437 }
1438
1439
1440 int btrfs_update_pinned_extents(struct btrfs_root *root,
1441 u64 bytenr, u64 num, int pin)
1442 {
1443 u64 len;
1444 struct btrfs_block_group_cache *cache;
1445 struct btrfs_fs_info *fs_info = root->fs_info;
1446
1447 WARN_ON(!mutex_is_locked(&root->fs_info->alloc_mutex));
1448 if (pin) {
1449 set_extent_dirty(&fs_info->pinned_extents,
1450 bytenr, bytenr + num - 1, GFP_NOFS);
1451 } else {
1452 clear_extent_dirty(&fs_info->pinned_extents,
1453 bytenr, bytenr + num - 1, GFP_NOFS);
1454 }
1455 while (num > 0) {
1456 cache = btrfs_lookup_block_group(fs_info, bytenr);
1457 if (!cache) {
1458 u64 first = first_logical_byte(root, bytenr);
1459 WARN_ON(first < bytenr);
1460 len = min(first - bytenr, num);
1461 } else {
1462 len = min(num, cache->key.offset -
1463 (bytenr - cache->key.objectid));
1464 }
1465 if (pin) {
1466 if (cache) {
1467 spin_lock(&cache->lock);
1468 cache->pinned += len;
1469 cache->space_info->bytes_pinned += len;
1470 spin_unlock(&cache->lock);
1471 }
1472 fs_info->total_pinned += len;
1473 } else {
1474 if (cache) {
1475 spin_lock(&cache->lock);
1476 cache->pinned -= len;
1477 cache->space_info->bytes_pinned -= len;
1478 spin_unlock(&cache->lock);
1479 }
1480 fs_info->total_pinned -= len;
1481 }
1482 bytenr += len;
1483 num -= len;
1484 }
1485 return 0;
1486 }
1487
1488 int btrfs_copy_pinned(struct btrfs_root *root, struct extent_io_tree *copy)
1489 {
1490 u64 last = 0;
1491 u64 start;
1492 u64 end;
1493 struct extent_io_tree *pinned_extents = &root->fs_info->pinned_extents;
1494 int ret;
1495
1496 while(1) {
1497 ret = find_first_extent_bit(pinned_extents, last,
1498 &start, &end, EXTENT_DIRTY);
1499 if (ret)
1500 break;
1501 set_extent_dirty(copy, start, end, GFP_NOFS);
1502 last = end + 1;
1503 }
1504 return 0;
1505 }
1506
1507 int btrfs_finish_extent_commit(struct btrfs_trans_handle *trans,
1508 struct btrfs_root *root,
1509 struct extent_io_tree *unpin)
1510 {
1511 u64 start;
1512 u64 end;
1513 int ret;
1514 struct btrfs_block_group_cache *cache;
1515
1516 mutex_lock(&root->fs_info->alloc_mutex);
1517 while(1) {
1518 ret = find_first_extent_bit(unpin, 0, &start, &end,
1519 EXTENT_DIRTY);
1520 if (ret)
1521 break;
1522 btrfs_update_pinned_extents(root, start, end + 1 - start, 0);
1523 clear_extent_dirty(unpin, start, end, GFP_NOFS);
1524 cache = btrfs_lookup_block_group(root->fs_info, start);
1525 if (cache->cached)
1526 btrfs_add_free_space(cache, start, end - start + 1);
1527 if (need_resched()) {
1528 mutex_unlock(&root->fs_info->alloc_mutex);
1529 cond_resched();
1530 mutex_lock(&root->fs_info->alloc_mutex);
1531 }
1532 }
1533 mutex_unlock(&root->fs_info->alloc_mutex);
1534 return 0;
1535 }
1536
1537 static int finish_current_insert(struct btrfs_trans_handle *trans,
1538 struct btrfs_root *extent_root)
1539 {
1540 u64 start;
1541 u64 end;
1542 struct btrfs_fs_info *info = extent_root->fs_info;
1543 struct extent_buffer *eb;
1544 struct btrfs_path *path;
1545 struct btrfs_key ins;
1546 struct btrfs_disk_key first;
1547 struct btrfs_extent_item extent_item;
1548 int ret;
1549 int level;
1550 int err = 0;
1551
1552 WARN_ON(!mutex_is_locked(&extent_root->fs_info->alloc_mutex));
1553 btrfs_set_stack_extent_refs(&extent_item, 1);
1554 btrfs_set_key_type(&ins, BTRFS_EXTENT_ITEM_KEY);
1555 path = btrfs_alloc_path();
1556
1557 while(1) {
1558 ret = find_first_extent_bit(&info->extent_ins, 0, &start,
1559 &end, EXTENT_LOCKED);
1560 if (ret)
1561 break;
1562
1563 ins.objectid = start;
1564 ins.offset = end + 1 - start;
1565 err = btrfs_insert_item(trans, extent_root, &ins,
1566 &extent_item, sizeof(extent_item));
1567 clear_extent_bits(&info->extent_ins, start, end, EXTENT_LOCKED,
1568 GFP_NOFS);
1569
1570 eb = btrfs_find_create_tree_block(extent_root, ins.objectid,
1571 ins.offset);
1572
1573 if (!btrfs_buffer_uptodate(eb, trans->transid))
1574 btrfs_read_buffer(eb, trans->transid);
1575
1576 btrfs_tree_lock(eb);
1577 level = btrfs_header_level(eb);
1578 if (level == 0) {
1579 btrfs_item_key(eb, &first, 0);
1580 } else {
1581 btrfs_node_key(eb, &first, 0);
1582 }
1583 btrfs_tree_unlock(eb);
1584 free_extent_buffer(eb);
1585 /*
1586 * the first key is just a hint, so the race we've created
1587 * against reading it is fine
1588 */
1589 err = btrfs_insert_extent_backref(trans, extent_root, path,
1590 start, extent_root->root_key.objectid,
1591 0, level,
1592 btrfs_disk_key_objectid(&first));
1593 BUG_ON(err);
1594 if (need_resched()) {
1595 mutex_unlock(&extent_root->fs_info->alloc_mutex);
1596 cond_resched();
1597 mutex_lock(&extent_root->fs_info->alloc_mutex);
1598 }
1599 }
1600 btrfs_free_path(path);
1601 return 0;
1602 }
1603
1604 static int pin_down_bytes(struct btrfs_root *root, u64 bytenr, u32 num_bytes,
1605 int is_data, int pending)
1606 {
1607 int err = 0;
1608
1609 WARN_ON(!mutex_is_locked(&root->fs_info->alloc_mutex));
1610 if (!pending) {
1611 struct extent_buffer *buf;
1612
1613 if (is_data)
1614 goto pinit;
1615
1616 buf = btrfs_find_tree_block(root, bytenr, num_bytes);
1617 if (buf) {
1618 /* we can reuse a block if it hasn't been written
1619 * and it is from this transaction. We can't
1620 * reuse anything from the tree log root because
1621 * it has tiny sub-transactions.
1622 */
1623 if (btrfs_buffer_uptodate(buf, 0) &&
1624 btrfs_try_tree_lock(buf)) {
1625 u64 transid =
1626 root->fs_info->running_transaction->transid;
1627 u64 header_transid =
1628 btrfs_header_generation(buf);
1629 if (btrfs_header_owner(buf) !=
1630 BTRFS_TREE_LOG_OBJECTID &&
1631 header_transid == transid &&
1632 !btrfs_header_flag(buf,
1633 BTRFS_HEADER_FLAG_WRITTEN)) {
1634 clean_tree_block(NULL, root, buf);
1635 btrfs_tree_unlock(buf);
1636 free_extent_buffer(buf);
1637 return 1;
1638 }
1639 btrfs_tree_unlock(buf);
1640 }
1641 free_extent_buffer(buf);
1642 }
1643 pinit:
1644 btrfs_update_pinned_extents(root, bytenr, num_bytes, 1);
1645 } else {
1646 set_extent_bits(&root->fs_info->pending_del,
1647 bytenr, bytenr + num_bytes - 1,
1648 EXTENT_LOCKED, GFP_NOFS);
1649 }
1650 BUG_ON(err < 0);
1651 return 0;
1652 }
1653
1654 /*
1655 * remove an extent from the root, returns 0 on success
1656 */
1657 static int __free_extent(struct btrfs_trans_handle *trans, struct btrfs_root
1658 *root, u64 bytenr, u64 num_bytes,
1659 u64 root_objectid, u64 ref_generation,
1660 u64 owner_objectid, u64 owner_offset, int pin,
1661 int mark_free)
1662 {
1663 struct btrfs_path *path;
1664 struct btrfs_key key;
1665 struct btrfs_fs_info *info = root->fs_info;
1666 struct btrfs_root *extent_root = info->extent_root;
1667 struct extent_buffer *leaf;
1668 int ret;
1669 int extent_slot = 0;
1670 int found_extent = 0;
1671 int num_to_del = 1;
1672 struct btrfs_extent_item *ei;
1673 u32 refs;
1674
1675 WARN_ON(!mutex_is_locked(&root->fs_info->alloc_mutex));
1676 key.objectid = bytenr;
1677 btrfs_set_key_type(&key, BTRFS_EXTENT_ITEM_KEY);
1678 key.offset = num_bytes;
1679 path = btrfs_alloc_path();
1680 if (!path)
1681 return -ENOMEM;
1682
1683 path->reada = 1;
1684 ret = lookup_extent_backref(trans, extent_root, path,
1685 bytenr, root_objectid,
1686 ref_generation,
1687 owner_objectid, owner_offset, 1);
1688 if (ret == 0) {
1689 struct btrfs_key found_key;
1690 extent_slot = path->slots[0];
1691 while(extent_slot > 0) {
1692 extent_slot--;
1693 btrfs_item_key_to_cpu(path->nodes[0], &found_key,
1694 extent_slot);
1695 if (found_key.objectid != bytenr)
1696 break;
1697 if (found_key.type == BTRFS_EXTENT_ITEM_KEY &&
1698 found_key.offset == num_bytes) {
1699 found_extent = 1;
1700 break;
1701 }
1702 if (path->slots[0] - extent_slot > 5)
1703 break;
1704 }
1705 if (!found_extent)
1706 ret = btrfs_del_item(trans, extent_root, path);
1707 } else {
1708 btrfs_print_leaf(extent_root, path->nodes[0]);
1709 WARN_ON(1);
1710 printk("Unable to find ref byte nr %Lu root %Lu "
1711 " gen %Lu owner %Lu offset %Lu\n", bytenr,
1712 root_objectid, ref_generation, owner_objectid,
1713 owner_offset);
1714 }
1715 if (!found_extent) {
1716 btrfs_release_path(extent_root, path);
1717 ret = btrfs_search_slot(trans, extent_root, &key, path, -1, 1);
1718 if (ret < 0)
1719 return ret;
1720 BUG_ON(ret);
1721 extent_slot = path->slots[0];
1722 }
1723
1724 leaf = path->nodes[0];
1725 ei = btrfs_item_ptr(leaf, extent_slot,
1726 struct btrfs_extent_item);
1727 refs = btrfs_extent_refs(leaf, ei);
1728 BUG_ON(refs == 0);
1729 refs -= 1;
1730 btrfs_set_extent_refs(leaf, ei, refs);
1731
1732 btrfs_mark_buffer_dirty(leaf);
1733
1734 if (refs == 0 && found_extent && path->slots[0] == extent_slot + 1) {
1735 /* if the back ref and the extent are next to each other
1736 * they get deleted below in one shot
1737 */
1738 path->slots[0] = extent_slot;
1739 num_to_del = 2;
1740 } else if (found_extent) {
1741 /* otherwise delete the extent back ref */
1742 ret = btrfs_del_item(trans, extent_root, path);
1743 BUG_ON(ret);
1744 /* if refs are 0, we need to setup the path for deletion */
1745 if (refs == 0) {
1746 btrfs_release_path(extent_root, path);
1747 ret = btrfs_search_slot(trans, extent_root, &key, path,
1748 -1, 1);
1749 if (ret < 0)
1750 return ret;
1751 BUG_ON(ret);
1752 }
1753 }
1754
1755 if (refs == 0) {
1756 u64 super_used;
1757 u64 root_used;
1758 #ifdef BIO_RW_DISCARD
1759 u64 map_length = num_bytes;
1760 struct btrfs_multi_bio *multi = NULL;
1761 #endif
1762
1763 if (pin) {
1764 ret = pin_down_bytes(root, bytenr, num_bytes,
1765 owner_objectid >= BTRFS_FIRST_FREE_OBJECTID, 0);
1766 if (ret > 0)
1767 mark_free = 1;
1768 BUG_ON(ret < 0);
1769 }
1770
1771 /* block accounting for super block */
1772 spin_lock_irq(&info->delalloc_lock);
1773 super_used = btrfs_super_bytes_used(&info->super_copy);
1774 btrfs_set_super_bytes_used(&info->super_copy,
1775 super_used - num_bytes);
1776 spin_unlock_irq(&info->delalloc_lock);
1777
1778 /* block accounting for root item */
1779 root_used = btrfs_root_used(&root->root_item);
1780 btrfs_set_root_used(&root->root_item,
1781 root_used - num_bytes);
1782 ret = btrfs_del_items(trans, extent_root, path, path->slots[0],
1783 num_to_del);
1784 if (ret) {
1785 return ret;
1786 }
1787 ret = update_block_group(trans, root, bytenr, num_bytes, 0,
1788 mark_free);
1789 BUG_ON(ret);
1790
1791 #ifdef BIO_RW_DISCARD
1792 /* Tell the block device(s) that the sectors can be discarded */
1793 ret = btrfs_map_block(&root->fs_info->mapping_tree, READ,
1794 bytenr, &map_length, &multi, 0);
1795 if (!ret) {
1796 struct btrfs_bio_stripe *stripe = multi->stripes;
1797 int i;
1798
1799 if (map_length > num_bytes)
1800 map_length = num_bytes;
1801
1802 for (i = 0; i < multi->num_stripes; i++, stripe++) {
1803 blkdev_issue_discard(stripe->dev->bdev,
1804 stripe->physical >> 9,
1805 map_length >> 9);
1806 }
1807 kfree(multi);
1808 }
1809 #endif
1810 }
1811 btrfs_free_path(path);
1812 finish_current_insert(trans, extent_root);
1813 return ret;
1814 }
1815
1816 /*
1817 * find all the blocks marked as pending in the radix tree and remove
1818 * them from the extent map
1819 */
1820 static int del_pending_extents(struct btrfs_trans_handle *trans, struct
1821 btrfs_root *extent_root)
1822 {
1823 int ret;
1824 int err = 0;
1825 u64 start;
1826 u64 end;
1827 struct extent_io_tree *pending_del;
1828 struct extent_io_tree *pinned_extents;
1829
1830 WARN_ON(!mutex_is_locked(&extent_root->fs_info->alloc_mutex));
1831 pending_del = &extent_root->fs_info->pending_del;
1832 pinned_extents = &extent_root->fs_info->pinned_extents;
1833
1834 while(1) {
1835 ret = find_first_extent_bit(pending_del, 0, &start, &end,
1836 EXTENT_LOCKED);
1837 if (ret)
1838 break;
1839 clear_extent_bits(pending_del, start, end, EXTENT_LOCKED,
1840 GFP_NOFS);
1841 if (!test_range_bit(&extent_root->fs_info->extent_ins,
1842 start, end, EXTENT_LOCKED, 0)) {
1843 btrfs_update_pinned_extents(extent_root, start,
1844 end + 1 - start, 1);
1845 ret = __free_extent(trans, extent_root,
1846 start, end + 1 - start,
1847 extent_root->root_key.objectid,
1848 0, 0, 0, 0, 0);
1849 } else {
1850 clear_extent_bits(&extent_root->fs_info->extent_ins,
1851 start, end, EXTENT_LOCKED, GFP_NOFS);
1852 }
1853 if (ret)
1854 err = ret;
1855
1856 if (need_resched()) {
1857 mutex_unlock(&extent_root->fs_info->alloc_mutex);
1858 cond_resched();
1859 mutex_lock(&extent_root->fs_info->alloc_mutex);
1860 }
1861 }
1862 return err;
1863 }
1864
1865 /*
1866 * remove an extent from the root, returns 0 on success
1867 */
1868 static int __btrfs_free_extent(struct btrfs_trans_handle *trans,
1869 struct btrfs_root *root, u64 bytenr,
1870 u64 num_bytes, u64 root_objectid,
1871 u64 ref_generation, u64 owner_objectid,
1872 u64 owner_offset, int pin)
1873 {
1874 struct btrfs_root *extent_root = root->fs_info->extent_root;
1875 int pending_ret;
1876 int ret;
1877
1878 WARN_ON(num_bytes < root->sectorsize);
1879 if (!root->ref_cows)
1880 ref_generation = 0;
1881
1882 if (root == extent_root) {
1883 pin_down_bytes(root, bytenr, num_bytes, 0, 1);
1884 return 0;
1885 }
1886 /* if metadata always pin */
1887 if (owner_objectid < BTRFS_FIRST_FREE_OBJECTID) {
1888 if (root->root_key.objectid == BTRFS_TREE_LOG_OBJECTID) {
1889 struct btrfs_block_group_cache *cache;
1890
1891 /* btrfs_free_reserved_extent */
1892 cache = btrfs_lookup_block_group(root->fs_info, bytenr);
1893 BUG_ON(!cache);
1894 btrfs_add_free_space(cache, bytenr, num_bytes);
1895 return 0;
1896 }
1897 pin = 1;
1898 }
1899
1900 /* if data pin when any transaction has committed this */
1901 if (ref_generation != trans->transid)
1902 pin = 1;
1903
1904 ret = __free_extent(trans, root, bytenr, num_bytes, root_objectid,
1905 ref_generation, owner_objectid, owner_offset,
1906 pin, pin == 0);
1907
1908 finish_current_insert(trans, root->fs_info->extent_root);
1909 pending_ret = del_pending_extents(trans, root->fs_info->extent_root);
1910 return ret ? ret : pending_ret;
1911 }
1912
1913 int btrfs_free_extent(struct btrfs_trans_handle *trans,
1914 struct btrfs_root *root, u64 bytenr,
1915 u64 num_bytes, u64 root_objectid,
1916 u64 ref_generation, u64 owner_objectid,
1917 u64 owner_offset, int pin)
1918 {
1919 int ret;
1920
1921 maybe_lock_mutex(root);
1922 ret = __btrfs_free_extent(trans, root, bytenr, num_bytes,
1923 root_objectid, ref_generation,
1924 owner_objectid, owner_offset, pin);
1925 maybe_unlock_mutex(root);
1926 return ret;
1927 }
1928
1929 static u64 stripe_align(struct btrfs_root *root, u64 val)
1930 {
1931 u64 mask = ((u64)root->stripesize - 1);
1932 u64 ret = (val + mask) & ~mask;
1933 return ret;
1934 }
1935
1936 /*
1937 * walks the btree of allocated extents and find a hole of a given size.
1938 * The key ins is changed to record the hole:
1939 * ins->objectid == block start
1940 * ins->flags = BTRFS_EXTENT_ITEM_KEY
1941 * ins->offset == number of blocks
1942 * Any available blocks before search_start are skipped.
1943 */
1944 static int noinline find_free_extent(struct btrfs_trans_handle *trans,
1945 struct btrfs_root *orig_root,
1946 u64 num_bytes, u64 empty_size,
1947 u64 search_start, u64 search_end,
1948 u64 hint_byte, struct btrfs_key *ins,
1949 u64 exclude_start, u64 exclude_nr,
1950 int data)
1951 {
1952 int ret;
1953 u64 orig_search_start;
1954 struct btrfs_root * root = orig_root->fs_info->extent_root;
1955 struct btrfs_fs_info *info = root->fs_info;
1956 u64 total_needed = num_bytes;
1957 u64 *last_ptr = NULL;
1958 struct btrfs_block_group_cache *block_group;
1959 int chunk_alloc_done = 0;
1960 int empty_cluster = 2 * 1024 * 1024;
1961 int allowed_chunk_alloc = 0;
1962
1963 WARN_ON(num_bytes < root->sectorsize);
1964 btrfs_set_key_type(ins, BTRFS_EXTENT_ITEM_KEY);
1965
1966 if (orig_root->ref_cows || empty_size)
1967 allowed_chunk_alloc = 1;
1968
1969 if (data & BTRFS_BLOCK_GROUP_METADATA) {
1970 last_ptr = &root->fs_info->last_alloc;
1971 empty_cluster = 256 * 1024;
1972 }
1973
1974 if ((data & BTRFS_BLOCK_GROUP_DATA) && btrfs_test_opt(root, SSD))
1975 last_ptr = &root->fs_info->last_data_alloc;
1976
1977 if (root->root_key.objectid == BTRFS_TREE_LOG_OBJECTID) {
1978 last_ptr = &root->fs_info->last_log_alloc;
1979 if (!last_ptr == 0 && root->fs_info->last_alloc) {
1980 *last_ptr = root->fs_info->last_alloc + empty_cluster;
1981 }
1982 }
1983
1984 if (last_ptr) {
1985 if (*last_ptr)
1986 hint_byte = *last_ptr;
1987 else
1988 empty_size += empty_cluster;
1989 }
1990
1991 search_start = max(search_start, first_logical_byte(root, 0));
1992 orig_search_start = search_start;
1993
1994 if (search_end == (u64)-1)
1995 search_end = btrfs_super_total_bytes(&info->super_copy);
1996
1997 search_start = max(search_start, hint_byte);
1998 total_needed += empty_size;
1999
2000 new_group:
2001 block_group = btrfs_lookup_block_group(info, search_start);
2002
2003 /*
2004 * Ok this looks a little tricky, buts its really simple. First if we
2005 * didn't find a block group obviously we want to start over.
2006 * Secondly, if the block group we found does not match the type we
2007 * need, and we have a last_ptr and its not 0, chances are the last
2008 * allocation we made was at the end of the block group, so lets go
2009 * ahead and skip the looking through the rest of the block groups and
2010 * start at the beginning. This helps with metadata allocations,
2011 * since you are likely to have a bunch of data block groups to search
2012 * through first before you realize that you need to start over, so go
2013 * ahead and start over and save the time.
2014 */
2015 if (!block_group || (!block_group_bits(block_group, data) &&
2016 last_ptr && *last_ptr)) {
2017 if (search_start != orig_search_start) {
2018 if (last_ptr && *last_ptr)
2019 *last_ptr = 0;
2020 search_start = orig_search_start;
2021 goto new_group;
2022 } else if (!chunk_alloc_done && allowed_chunk_alloc) {
2023 ret = do_chunk_alloc(trans, root,
2024 num_bytes + 2 * 1024 * 1024,
2025 data, 1);
2026 if (ret < 0) {
2027 struct btrfs_space_info *info;
2028
2029 info = __find_space_info(root->fs_info, data);
2030 goto error;
2031 }
2032 BUG_ON(ret);
2033 chunk_alloc_done = 1;
2034 search_start = orig_search_start;
2035 goto new_group;
2036 } else {
2037 ret = -ENOSPC;
2038 goto error;
2039 }
2040 }
2041
2042 /*
2043 * this is going to seach through all of the existing block groups it
2044 * can find, so if we don't find something we need to see if we can
2045 * allocate what we need.
2046 */
2047 ret = find_free_space(root, &block_group, &search_start,
2048 total_needed, data);
2049 if (ret == -ENOSPC) {
2050 /*
2051 * instead of allocating, start at the original search start
2052 * and see if there is something to be found, if not then we
2053 * allocate
2054 */
2055 if (search_start != orig_search_start) {
2056 if (last_ptr && *last_ptr) {
2057 *last_ptr = 0;
2058 total_needed += empty_cluster;
2059 }
2060 search_start = orig_search_start;
2061 goto new_group;
2062 }
2063
2064 /*
2065 * we've already allocated, we're pretty screwed
2066 */
2067 if (chunk_alloc_done) {
2068 goto error;
2069 } else if (!allowed_chunk_alloc && block_group &&
2070 block_group_bits(block_group, data)) {
2071 block_group->space_info->force_alloc = 1;
2072 goto error;
2073 } else if (!allowed_chunk_alloc) {
2074 goto error;
2075 }
2076
2077 ret = do_chunk_alloc(trans, root, num_bytes + 2 * 1024 * 1024,
2078 data, 1);
2079 if (ret < 0)
2080 goto error;
2081
2082 BUG_ON(ret);
2083 chunk_alloc_done = 1;
2084 if (block_group)
2085 search_start = block_group->key.objectid +
2086 block_group->key.offset;
2087 else
2088 search_start = orig_search_start;
2089 goto new_group;
2090 }
2091
2092 if (ret)
2093 goto error;
2094
2095 search_start = stripe_align(root, search_start);
2096 ins->objectid = search_start;
2097 ins->offset = num_bytes;
2098
2099 if (ins->objectid + num_bytes >= search_end) {
2100 search_start = orig_search_start;
2101 if (chunk_alloc_done) {
2102 ret = -ENOSPC;
2103 goto error;
2104 }
2105 goto new_group;
2106 }
2107
2108 if (ins->objectid + num_bytes >
2109 block_group->key.objectid + block_group->key.offset) {
2110 if (search_start == orig_search_start && chunk_alloc_done) {
2111 ret = -ENOSPC;
2112 goto error;
2113 }
2114 search_start = block_group->key.objectid +
2115 block_group->key.offset;
2116 goto new_group;
2117 }
2118
2119 if (exclude_nr > 0 && (ins->objectid + num_bytes > exclude_start &&
2120 ins->objectid < exclude_start + exclude_nr)) {
2121 search_start = exclude_start + exclude_nr;
2122 goto new_group;
2123 }
2124
2125 if (!(data & BTRFS_BLOCK_GROUP_DATA))
2126 trans->block_group = block_group;
2127
2128 ins->offset = num_bytes;
2129 if (last_ptr) {
2130 *last_ptr = ins->objectid + ins->offset;
2131 if (*last_ptr ==
2132 btrfs_super_total_bytes(&root->fs_info->super_copy))
2133 *last_ptr = 0;
2134 }
2135
2136 ret = 0;
2137 error:
2138 return ret;
2139 }
2140
2141 static void dump_space_info(struct btrfs_space_info *info, u64 bytes)
2142 {
2143 struct btrfs_block_group_cache *cache;
2144 struct list_head *l;
2145
2146 printk(KERN_INFO "space_info has %Lu free, is %sfull\n",
2147 info->total_bytes - info->bytes_used - info->bytes_pinned,
2148 (info->full) ? "" : "not ");
2149
2150 spin_lock(&info->lock);
2151 list_for_each(l, &info->block_groups) {
2152 cache = list_entry(l, struct btrfs_block_group_cache, list);
2153 spin_lock(&cache->lock);
2154 printk(KERN_INFO "block group %Lu has %Lu bytes, %Lu used "
2155 "%Lu pinned\n",
2156 cache->key.objectid, cache->key.offset,
2157 btrfs_block_group_used(&cache->item), cache->pinned);
2158 btrfs_dump_free_space(cache, bytes);
2159 spin_unlock(&cache->lock);
2160 }
2161 spin_unlock(&info->lock);
2162 }
2163 static int __btrfs_reserve_extent(struct btrfs_trans_handle *trans,
2164 struct btrfs_root *root,
2165 u64 num_bytes, u64 min_alloc_size,
2166 u64 empty_size, u64 hint_byte,
2167 u64 search_end, struct btrfs_key *ins,
2168 u64 data)
2169 {
2170 int ret;
2171 u64 search_start = 0;
2172 u64 alloc_profile;
2173 struct btrfs_fs_info *info = root->fs_info;
2174 struct btrfs_block_group_cache *cache;
2175
2176 if (data) {
2177 alloc_profile = info->avail_data_alloc_bits &
2178 info->data_alloc_profile;
2179 data = BTRFS_BLOCK_GROUP_DATA | alloc_profile;
2180 } else if (root == root->fs_info->chunk_root) {
2181 alloc_profile = info->avail_system_alloc_bits &
2182 info->system_alloc_profile;
2183 data = BTRFS_BLOCK_GROUP_SYSTEM | alloc_profile;
2184 } else {
2185 alloc_profile = info->avail_metadata_alloc_bits &
2186 info->metadata_alloc_profile;
2187 data = BTRFS_BLOCK_GROUP_METADATA | alloc_profile;
2188 }
2189 again:
2190 data = reduce_alloc_profile(root, data);
2191 /*
2192 * the only place that sets empty_size is btrfs_realloc_node, which
2193 * is not called recursively on allocations
2194 */
2195 if (empty_size || root->ref_cows) {
2196 if (!(data & BTRFS_BLOCK_GROUP_METADATA)) {
2197 ret = do_chunk_alloc(trans, root->fs_info->extent_root,
2198 2 * 1024 * 1024,
2199 BTRFS_BLOCK_GROUP_METADATA |
2200 (info->metadata_alloc_profile &
2201 info->avail_metadata_alloc_bits), 0);
2202 }
2203 ret = do_chunk_alloc(trans, root->fs_info->extent_root,
2204 num_bytes + 2 * 1024 * 1024, data, 0);
2205 }
2206
2207 WARN_ON(num_bytes < root->sectorsize);
2208 ret = find_free_extent(trans, root, num_bytes, empty_size,
2209 search_start, search_end, hint_byte, ins,
2210 trans->alloc_exclude_start,
2211 trans->alloc_exclude_nr, data);
2212
2213 if (ret == -ENOSPC && num_bytes > min_alloc_size) {
2214 num_bytes = num_bytes >> 1;
2215 num_bytes = num_bytes & ~(root->sectorsize - 1);
2216 num_bytes = max(num_bytes, min_alloc_size);
2217 do_chunk_alloc(trans, root->fs_info->extent_root,
2218 num_bytes, data, 1);
2219 goto again;
2220 }
2221 if (ret) {
2222 struct btrfs_space_info *sinfo;
2223
2224 sinfo = __find_space_info(root->fs_info, data);
2225 printk("allocation failed flags %Lu, wanted %Lu\n",
2226 data, num_bytes);
2227 dump_space_info(sinfo, num_bytes);
2228 BUG();
2229 }
2230 cache = btrfs_lookup_block_group(root->fs_info, ins->objectid);
2231 if (!cache) {
2232 printk(KERN_ERR "Unable to find block group for %Lu\n", ins->objectid);
2233 return -ENOSPC;
2234 }
2235
2236 ret = btrfs_remove_free_space(cache, ins->objectid, ins->offset);
2237
2238 return ret;
2239 }
2240
2241 int btrfs_free_reserved_extent(struct btrfs_root *root, u64 start, u64 len)
2242 {
2243 struct btrfs_block_group_cache *cache;
2244
2245 maybe_lock_mutex(root);
2246 cache = btrfs_lookup_block_group(root->fs_info, start);
2247 if (!cache) {
2248 printk(KERN_ERR "Unable to find block group for %Lu\n", start);
2249 maybe_unlock_mutex(root);
2250 return -ENOSPC;
2251 }
2252 btrfs_add_free_space(cache, start, len);
2253 maybe_unlock_mutex(root);
2254 return 0;
2255 }
2256
2257 int btrfs_reserve_extent(struct btrfs_trans_handle *trans,
2258 struct btrfs_root *root,
2259 u64 num_bytes, u64 min_alloc_size,
2260 u64 empty_size, u64 hint_byte,
2261 u64 search_end, struct btrfs_key *ins,
2262 u64 data)
2263 {
2264 int ret;
2265 maybe_lock_mutex(root);
2266 ret = __btrfs_reserve_extent(trans, root, num_bytes, min_alloc_size,
2267 empty_size, hint_byte, search_end, ins,
2268 data);
2269 maybe_unlock_mutex(root);
2270 return ret;
2271 }
2272
2273 static int __btrfs_alloc_reserved_extent(struct btrfs_trans_handle *trans,
2274 struct btrfs_root *root,
2275 u64 root_objectid, u64 ref_generation,
2276 u64 owner, u64 owner_offset,
2277 struct btrfs_key *ins)
2278 {
2279 int ret;
2280 int pending_ret;
2281 u64 super_used;
2282 u64 root_used;
2283 u64 num_bytes = ins->offset;
2284 u32 sizes[2];
2285 struct btrfs_fs_info *info = root->fs_info;
2286 struct btrfs_root *extent_root = info->extent_root;
2287 struct btrfs_extent_item *extent_item;
2288 struct btrfs_extent_ref *ref;
2289 struct btrfs_path *path;
2290 struct btrfs_key keys[2];
2291
2292 /* block accounting for super block */
2293 spin_lock_irq(&info->delalloc_lock);
2294 super_used = btrfs_super_bytes_used(&info->super_copy);
2295 btrfs_set_super_bytes_used(&info->super_copy, super_used + num_bytes);
2296 spin_unlock_irq(&info->delalloc_lock);
2297
2298 /* block accounting for root item */
2299 root_used = btrfs_root_used(&root->root_item);
2300 btrfs_set_root_used(&root->root_item, root_used + num_bytes);
2301
2302 if (root == extent_root) {
2303 set_extent_bits(&root->fs_info->extent_ins, ins->objectid,
2304 ins->objectid + ins->offset - 1,
2305 EXTENT_LOCKED, GFP_NOFS);
2306 goto update_block;
2307 }
2308
2309 memcpy(&keys[0], ins, sizeof(*ins));
2310 keys[1].offset = hash_extent_ref(root_objectid, ref_generation,
2311 owner, owner_offset);
2312 keys[1].objectid = ins->objectid;
2313 keys[1].type = BTRFS_EXTENT_REF_KEY;
2314 sizes[0] = sizeof(*extent_item);
2315 sizes[1] = sizeof(*ref);
2316
2317 path = btrfs_alloc_path();
2318 BUG_ON(!path);
2319
2320 ret = btrfs_insert_empty_items(trans, extent_root, path, keys,
2321 sizes, 2);
2322 BUG_ON(ret);
2323
2324 extent_item = btrfs_item_ptr(path->nodes[0], path->slots[0],
2325 struct btrfs_extent_item);
2326 btrfs_set_extent_refs(path->nodes[0], extent_item, 1);
2327 ref = btrfs_item_ptr(path->nodes[0], path->slots[0] + 1,
2328 struct btrfs_extent_ref);
2329
2330 btrfs_set_ref_root(path->nodes[0], ref, root_objectid);
2331 btrfs_set_ref_generation(path->nodes[0], ref, ref_generation);
2332 btrfs_set_ref_objectid(path->nodes[0], ref, owner);
2333 btrfs_set_ref_offset(path->nodes[0], ref, owner_offset);
2334
2335 btrfs_mark_buffer_dirty(path->nodes[0]);
2336
2337 trans->alloc_exclude_start = 0;
2338 trans->alloc_exclude_nr = 0;
2339 btrfs_free_path(path);
2340 finish_current_insert(trans, extent_root);
2341 pending_ret = del_pending_extents(trans, extent_root);
2342
2343 if (ret)
2344 goto out;
2345 if (pending_ret) {
2346 ret = pending_ret;
2347 goto out;
2348 }
2349
2350 update_block:
2351 ret = update_block_group(trans, root, ins->objectid, ins->offset, 1, 0);
2352 if (ret) {
2353 printk("update block group failed for %Lu %Lu\n",
2354 ins->objectid, ins->offset);
2355 BUG();
2356 }
2357 out:
2358 return ret;
2359 }
2360
2361 int btrfs_alloc_reserved_extent(struct btrfs_trans_handle *trans,
2362 struct btrfs_root *root,
2363 u64 root_objectid, u64 ref_generation,
2364 u64 owner, u64 owner_offset,
2365 struct btrfs_key *ins)
2366 {
2367 int ret;
2368 maybe_lock_mutex(root);
2369 ret = __btrfs_alloc_reserved_extent(trans, root, root_objectid,
2370 ref_generation, owner,
2371 owner_offset, ins);
2372 maybe_unlock_mutex(root);
2373 return ret;
2374 }
2375
2376 /*
2377 * this is used by the tree logging recovery code. It records that
2378 * an extent has been allocated and makes sure to clear the free
2379 * space cache bits as well
2380 */
2381 int btrfs_alloc_logged_extent(struct btrfs_trans_handle *trans,
2382 struct btrfs_root *root,
2383 u64 root_objectid, u64 ref_generation,
2384 u64 owner, u64 owner_offset,
2385 struct btrfs_key *ins)
2386 {
2387 int ret;
2388 struct btrfs_block_group_cache *block_group;
2389
2390 maybe_lock_mutex(root);
2391 block_group = btrfs_lookup_block_group(root->fs_info, ins->objectid);
2392 cache_block_group(root, block_group);
2393
2394 ret = btrfs_remove_free_space(block_group, ins->objectid, ins->offset);
2395 BUG_ON(ret);
2396
2397 ret = __btrfs_alloc_reserved_extent(trans, root, root_objectid,
2398 ref_generation, owner,
2399 owner_offset, ins);
2400 maybe_unlock_mutex(root);
2401 return ret;
2402 }
2403
2404 /*
2405 * finds a free extent and does all the dirty work required for allocation
2406 * returns the key for the extent through ins, and a tree buffer for
2407 * the first block of the extent through buf.
2408 *
2409 * returns 0 if everything worked, non-zero otherwise.
2410 */
2411 int btrfs_alloc_extent(struct btrfs_trans_handle *trans,
2412 struct btrfs_root *root,
2413 u64 num_bytes, u64 min_alloc_size,
2414 u64 root_objectid, u64 ref_generation,
2415 u64 owner, u64 owner_offset,
2416 u64 empty_size, u64 hint_byte,
2417 u64 search_end, struct btrfs_key *ins, u64 data)
2418 {
2419 int ret;
2420
2421 maybe_lock_mutex(root);
2422
2423 ret = __btrfs_reserve_extent(trans, root, num_bytes,
2424 min_alloc_size, empty_size, hint_byte,
2425 search_end, ins, data);
2426 BUG_ON(ret);
2427 if (root_objectid != BTRFS_TREE_LOG_OBJECTID) {
2428 ret = __btrfs_alloc_reserved_extent(trans, root, root_objectid,
2429 ref_generation, owner,
2430 owner_offset, ins);
2431 BUG_ON(ret);
2432
2433 }
2434 maybe_unlock_mutex(root);
2435 return ret;
2436 }
2437
2438 struct extent_buffer *btrfs_init_new_buffer(struct btrfs_trans_handle *trans,
2439 struct btrfs_root *root,
2440 u64 bytenr, u32 blocksize)
2441 {
2442 struct extent_buffer *buf;
2443
2444 buf = btrfs_find_create_tree_block(root, bytenr, blocksize);
2445 if (!buf)
2446 return ERR_PTR(-ENOMEM);
2447 btrfs_set_header_generation(buf, trans->transid);
2448 btrfs_tree_lock(buf);
2449 clean_tree_block(trans, root, buf);
2450 btrfs_set_buffer_uptodate(buf);
2451 if (root->root_key.objectid == BTRFS_TREE_LOG_OBJECTID) {
2452 set_extent_dirty(&root->dirty_log_pages, buf->start,
2453 buf->start + buf->len - 1, GFP_NOFS);
2454 } else {
2455 set_extent_dirty(&trans->transaction->dirty_pages, buf->start,
2456 buf->start + buf->len - 1, GFP_NOFS);
2457 }
2458 trans->blocks_used++;
2459 return buf;
2460 }
2461
2462 /*
2463 * helper function to allocate a block for a given tree
2464 * returns the tree buffer or NULL.
2465 */
2466 struct extent_buffer *btrfs_alloc_free_block(struct btrfs_trans_handle *trans,
2467 struct btrfs_root *root,
2468 u32 blocksize,
2469 u64 root_objectid,
2470 u64 ref_generation,
2471 u64 first_objectid,
2472 int level,
2473 u64 hint,
2474 u64 empty_size)
2475 {
2476 struct btrfs_key ins;
2477 int ret;
2478 struct extent_buffer *buf;
2479
2480 ret = btrfs_alloc_extent(trans, root, blocksize, blocksize,
2481 root_objectid, ref_generation,
2482 level, first_objectid, empty_size, hint,
2483 (u64)-1, &ins, 0);
2484 if (ret) {
2485 BUG_ON(ret > 0);
2486 return ERR_PTR(ret);
2487 }
2488
2489 buf = btrfs_init_new_buffer(trans, root, ins.objectid, blocksize);
2490 return buf;
2491 }
2492
2493 int btrfs_drop_leaf_ref(struct btrfs_trans_handle *trans,
2494 struct btrfs_root *root, struct extent_buffer *leaf)
2495 {
2496 u64 leaf_owner;
2497 u64 leaf_generation;
2498 struct btrfs_key key;
2499 struct btrfs_file_extent_item *fi;
2500 int i;
2501 int nritems;
2502 int ret;
2503
2504 BUG_ON(!btrfs_is_leaf(leaf));
2505 nritems = btrfs_header_nritems(leaf);
2506 leaf_owner = btrfs_header_owner(leaf);
2507 leaf_generation = btrfs_header_generation(leaf);
2508
2509 for (i = 0; i < nritems; i++) {
2510 u64 disk_bytenr;
2511 cond_resched();
2512
2513 btrfs_item_key_to_cpu(leaf, &key, i);
2514 if (btrfs_key_type(&key) != BTRFS_EXTENT_DATA_KEY)
2515 continue;
2516 fi = btrfs_item_ptr(leaf, i, struct btrfs_file_extent_item);
2517 if (btrfs_file_extent_type(leaf, fi) ==
2518 BTRFS_FILE_EXTENT_INLINE)
2519 continue;
2520 /*
2521 * FIXME make sure to insert a trans record that
2522 * repeats the snapshot del on crash
2523 */
2524 disk_bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
2525 if (disk_bytenr == 0)
2526 continue;
2527
2528 mutex_lock(&root->fs_info->alloc_mutex);
2529 ret = __btrfs_free_extent(trans, root, disk_bytenr,
2530 btrfs_file_extent_disk_num_bytes(leaf, fi),
2531 leaf_owner, leaf_generation,
2532 key.objectid, key.offset, 0);
2533 mutex_unlock(&root->fs_info->alloc_mutex);
2534
2535 atomic_inc(&root->fs_info->throttle_gen);
2536 wake_up(&root->fs_info->transaction_throttle);
2537 cond_resched();
2538
2539 BUG_ON(ret);
2540 }
2541 return 0;
2542 }
2543
2544 static int noinline cache_drop_leaf_ref(struct btrfs_trans_handle *trans,
2545 struct btrfs_root *root,
2546 struct btrfs_leaf_ref *ref)
2547 {
2548 int i;
2549 int ret;
2550 struct btrfs_extent_info *info = ref->extents;
2551
2552 for (i = 0; i < ref->nritems; i++) {
2553 mutex_lock(&root->fs_info->alloc_mutex);
2554 ret = __btrfs_free_extent(trans, root,
2555 info->bytenr, info->num_bytes,
2556 ref->owner, ref->generation,
2557 info->objectid, info->offset, 0);
2558 mutex_unlock(&root->fs_info->alloc_mutex);
2559
2560 atomic_inc(&root->fs_info->throttle_gen);
2561 wake_up(&root->fs_info->transaction_throttle);
2562 cond_resched();
2563
2564 BUG_ON(ret);
2565 info++;
2566 }
2567
2568 return 0;
2569 }
2570
2571 int drop_snap_lookup_refcount(struct btrfs_root *root, u64 start, u64 len,
2572 u32 *refs)
2573 {
2574 int ret;
2575
2576 ret = lookup_extent_ref(NULL, root, start, len, refs);
2577 BUG_ON(ret);
2578
2579 #if 0 // some debugging code in case we see problems here
2580 /* if the refs count is one, it won't get increased again. But
2581 * if the ref count is > 1, someone may be decreasing it at
2582 * the same time we are.
2583 */
2584 if (*refs != 1) {
2585 struct extent_buffer *eb = NULL;
2586 eb = btrfs_find_create_tree_block(root, start, len);
2587 if (eb)
2588 btrfs_tree_lock(eb);
2589
2590 mutex_lock(&root->fs_info->alloc_mutex);
2591 ret = lookup_extent_ref(NULL, root, start, len, refs);
2592 BUG_ON(ret);
2593 mutex_unlock(&root->fs_info->alloc_mutex);
2594
2595 if (eb) {
2596 btrfs_tree_unlock(eb);
2597 free_extent_buffer(eb);
2598 }
2599 if (*refs == 1) {
2600 printk("block %llu went down to one during drop_snap\n",
2601 (unsigned long long)start);
2602 }
2603
2604 }
2605 #endif
2606
2607 cond_resched();
2608 return ret;
2609 }
2610
2611 /*
2612 * helper function for drop_snapshot, this walks down the tree dropping ref
2613 * counts as it goes.
2614 */
2615 static int noinline walk_down_tree(struct btrfs_trans_handle *trans,
2616 struct btrfs_root *root,
2617 struct btrfs_path *path, int *level)
2618 {
2619 u64 root_owner;
2620 u64 root_gen;
2621 u64 bytenr;
2622 u64 ptr_gen;
2623 struct extent_buffer *next;
2624 struct extent_buffer *cur;
2625 struct extent_buffer *parent;
2626 struct btrfs_leaf_ref *ref;
2627 u32 blocksize;
2628 int ret;
2629 u32 refs;
2630
2631 WARN_ON(*level < 0);
2632 WARN_ON(*level >= BTRFS_MAX_LEVEL);
2633 ret = drop_snap_lookup_refcount(root, path->nodes[*level]->start,
2634 path->nodes[*level]->len, &refs);
2635 BUG_ON(ret);
2636 if (refs > 1)
2637 goto out;
2638
2639 /*
2640 * walk down to the last node level and free all the leaves
2641 */
2642 while(*level >= 0) {
2643 WARN_ON(*level < 0);
2644 WARN_ON(*level >= BTRFS_MAX_LEVEL);
2645 cur = path->nodes[*level];
2646
2647 if (btrfs_header_level(cur) != *level)
2648 WARN_ON(1);
2649
2650 if (path->slots[*level] >=
2651 btrfs_header_nritems(cur))
2652 break;
2653 if (*level == 0) {
2654 ret = btrfs_drop_leaf_ref(trans, root, cur);
2655 BUG_ON(ret);
2656 break;
2657 }
2658 bytenr = btrfs_node_blockptr(cur, path->slots[*level]);
2659 ptr_gen = btrfs_node_ptr_generation(cur, path->slots[*level]);
2660 blocksize = btrfs_level_size(root, *level - 1);
2661
2662 ret = drop_snap_lookup_refcount(root, bytenr, blocksize, &refs);
2663 BUG_ON(ret);
2664 if (refs != 1) {
2665 parent = path->nodes[*level];
2666 root_owner = btrfs_header_owner(parent);
2667 root_gen = btrfs_header_generation(parent);
2668 path->slots[*level]++;
2669
2670 mutex_lock(&root->fs_info->alloc_mutex);
2671 ret = __btrfs_free_extent(trans, root, bytenr,
2672 blocksize, root_owner,
2673 root_gen, 0, 0, 1);
2674 BUG_ON(ret);
2675 mutex_unlock(&root->fs_info->alloc_mutex);
2676
2677 atomic_inc(&root->fs_info->throttle_gen);
2678 wake_up(&root->fs_info->transaction_throttle);
2679 cond_resched();
2680
2681 continue;
2682 }
2683 /*
2684 * at this point, we have a single ref, and since the
2685 * only place referencing this extent is a dead root
2686 * the reference count should never go higher.
2687 * So, we don't need to check it again
2688 */
2689 if (*level == 1) {
2690 struct btrfs_key key;
2691 btrfs_node_key_to_cpu(cur, &key, path->slots[*level]);
2692 ref = btrfs_lookup_leaf_ref(root, bytenr);
2693 if (ref) {
2694 ret = cache_drop_leaf_ref(trans, root, ref);
2695 BUG_ON(ret);
2696 btrfs_remove_leaf_ref(root, ref);
2697 btrfs_free_leaf_ref(root, ref);
2698 *level = 0;
2699 break;
2700 }
2701 if (printk_ratelimit())
2702 printk("leaf ref miss for bytenr %llu\n",
2703 (unsigned long long)bytenr);
2704 }
2705 next = btrfs_find_tree_block(root, bytenr, blocksize);
2706 if (!next || !btrfs_buffer_uptodate(next, ptr_gen)) {
2707 free_extent_buffer(next);
2708
2709 next = read_tree_block(root, bytenr, blocksize,
2710 ptr_gen);
2711 cond_resched();
2712 #if 0
2713 /*
2714 * this is a debugging check and can go away
2715 * the ref should never go all the way down to 1
2716 * at this point
2717 */
2718 ret = lookup_extent_ref(NULL, root, bytenr, blocksize,
2719 &refs);
2720 BUG_ON(ret);
2721 WARN_ON(refs != 1);
2722 #endif
2723 }
2724 WARN_ON(*level <= 0);
2725 if (path->nodes[*level-1])
2726 free_extent_buffer(path->nodes[*level-1]);
2727 path->nodes[*level-1] = next;
2728 *level = btrfs_header_level(next);
2729 path->slots[*level] = 0;
2730 cond_resched();
2731 }
2732 out:
2733 WARN_ON(*level < 0);
2734 WARN_ON(*level >= BTRFS_MAX_LEVEL);
2735
2736 if (path->nodes[*level] == root->node) {
2737 parent = path->nodes[*level];
2738 bytenr = path->nodes[*level]->start;
2739 } else {
2740 parent = path->nodes[*level + 1];
2741 bytenr = btrfs_node_blockptr(parent, path->slots[*level + 1]);
2742 }
2743
2744 blocksize = btrfs_level_size(root, *level);
2745 root_owner = btrfs_header_owner(parent);
2746 root_gen = btrfs_header_generation(parent);
2747
2748 mutex_lock(&root->fs_info->alloc_mutex);
2749 ret = __btrfs_free_extent(trans, root, bytenr, blocksize,
2750 root_owner, root_gen, 0, 0, 1);
2751 free_extent_buffer(path->nodes[*level]);
2752 path->nodes[*level] = NULL;
2753 *level += 1;
2754 BUG_ON(ret);
2755 mutex_unlock(&root->fs_info->alloc_mutex);
2756
2757 cond_resched();
2758 return 0;
2759 }
2760
2761 /*
2762 * helper for dropping snapshots. This walks back up the tree in the path
2763 * to find the first node higher up where we haven't yet gone through
2764 * all the slots
2765 */
2766 static int noinline walk_up_tree(struct btrfs_trans_handle *trans,
2767 struct btrfs_root *root,
2768 struct btrfs_path *path, int *level)
2769 {
2770 u64 root_owner;
2771 u64 root_gen;
2772 struct btrfs_root_item *root_item = &root->root_item;
2773 int i;
2774 int slot;
2775 int ret;
2776
2777 for(i = *level; i < BTRFS_MAX_LEVEL - 1 && path->nodes[i]; i++) {
2778 slot = path->slots[i];
2779 if (slot < btrfs_header_nritems(path->nodes[i]) - 1) {
2780 struct extent_buffer *node;
2781 struct btrfs_disk_key disk_key;
2782 node = path->nodes[i];
2783 path->slots[i]++;
2784 *level = i;
2785 WARN_ON(*level == 0);
2786 btrfs_node_key(node, &disk_key, path->slots[i]);
2787 memcpy(&root_item->drop_progress,
2788 &disk_key, sizeof(disk_key));
2789 root_item->drop_level = i;
2790 return 0;
2791 } else {
2792 if (path->nodes[*level] == root->node) {
2793 root_owner = root->root_key.objectid;
2794 root_gen =
2795 btrfs_header_generation(path->nodes[*level]);
2796 } else {
2797 struct extent_buffer *node;
2798 node = path->nodes[*level + 1];
2799 root_owner = btrfs_header_owner(node);
2800 root_gen = btrfs_header_generation(node);
2801 }
2802 ret = btrfs_free_extent(trans, root,
2803 path->nodes[*level]->start,
2804 path->nodes[*level]->len,
2805 root_owner, root_gen, 0, 0, 1);
2806 BUG_ON(ret);
2807 free_extent_buffer(path->nodes[*level]);
2808 path->nodes[*level] = NULL;
2809 *level = i + 1;
2810 }
2811 }
2812 return 1;
2813 }
2814
2815 /*
2816 * drop the reference count on the tree rooted at 'snap'. This traverses
2817 * the tree freeing any blocks that have a ref count of zero after being
2818 * decremented.
2819 */
2820 int btrfs_drop_snapshot(struct btrfs_trans_handle *trans, struct btrfs_root
2821 *root)
2822 {
2823 int ret = 0;
2824 int wret;
2825 int level;
2826 struct btrfs_path *path;
2827 int i;
2828 int orig_level;
2829 struct btrfs_root_item *root_item = &root->root_item;
2830
2831 WARN_ON(!mutex_is_locked(&root->fs_info->drop_mutex));
2832 path = btrfs_alloc_path();
2833 BUG_ON(!path);
2834
2835 level = btrfs_header_level(root->node);
2836 orig_level = level;
2837 if (btrfs_disk_key_objectid(&root_item->drop_progress) == 0) {
2838 path->nodes[level] = root->node;
2839 extent_buffer_get(root->node);
2840 path->slots[level] = 0;
2841 } else {
2842 struct btrfs_key key;
2843 struct btrfs_disk_key found_key;
2844 struct extent_buffer *node;
2845
2846 btrfs_disk_key_to_cpu(&key, &root_item->drop_progress);
2847 level = root_item->drop_level;
2848 path->lowest_level = level;
2849 wret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
2850 if (wret < 0) {
2851 ret = wret;
2852 goto out;
2853 }
2854 node = path->nodes[level];
2855 btrfs_node_key(node, &found_key, path->slots[level]);
2856 WARN_ON(memcmp(&found_key, &root_item->drop_progress,
2857 sizeof(found_key)));
2858 /*
2859 * unlock our path, this is safe because only this
2860 * function is allowed to delete this snapshot
2861 */
2862 for (i = 0; i < BTRFS_MAX_LEVEL; i++) {
2863 if (path->nodes[i] && path->locks[i]) {
2864 path->locks[i] = 0;
2865 btrfs_tree_unlock(path->nodes[i]);
2866 }
2867 }
2868 }
2869 while(1) {
2870 wret = walk_down_tree(trans, root, path, &level);
2871 if (wret > 0)
2872 break;
2873 if (wret < 0)
2874 ret = wret;
2875
2876 wret = walk_up_tree(trans, root, path, &level);
2877 if (wret > 0)
2878 break;
2879 if (wret < 0)
2880 ret = wret;
2881 if (trans->transaction->in_commit) {
2882 ret = -EAGAIN;
2883 break;
2884 }
2885 atomic_inc(&root->fs_info->throttle_gen);
2886 wake_up(&root->fs_info->transaction_throttle);
2887 }
2888 for (i = 0; i <= orig_level; i++) {
2889 if (path->nodes[i]) {
2890 free_extent_buffer(path->nodes[i]);
2891 path->nodes[i] = NULL;
2892 }
2893 }
2894 out:
2895 btrfs_free_path(path);
2896 return ret;
2897 }
2898
2899 int btrfs_free_block_groups(struct btrfs_fs_info *info)
2900 {
2901 struct btrfs_block_group_cache *block_group;
2902 struct rb_node *n;
2903
2904 mutex_lock(&info->alloc_mutex);
2905 spin_lock(&info->block_group_cache_lock);
2906 while ((n = rb_last(&info->block_group_cache_tree)) != NULL) {
2907 block_group = rb_entry(n, struct btrfs_block_group_cache,
2908 cache_node);
2909
2910 btrfs_remove_free_space_cache(block_group);
2911 rb_erase(&block_group->cache_node,
2912 &info->block_group_cache_tree);
2913 spin_lock(&block_group->space_info->lock);
2914 list_del(&block_group->list);
2915 spin_unlock(&block_group->space_info->lock);
2916 kfree(block_group);
2917 }
2918 spin_unlock(&info->block_group_cache_lock);
2919 mutex_unlock(&info->alloc_mutex);
2920 return 0;
2921 }
2922
2923 static unsigned long calc_ra(unsigned long start, unsigned long last,
2924 unsigned long nr)
2925 {
2926 return min(last, start + nr - 1);
2927 }
2928
2929 static int noinline relocate_inode_pages(struct inode *inode, u64 start,
2930 u64 len)
2931 {
2932 u64 page_start;
2933 u64 page_end;
2934 unsigned long last_index;
2935 unsigned long i;
2936 struct page *page;
2937 struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
2938 struct file_ra_state *ra;
2939 unsigned long total_read = 0;
2940 unsigned long ra_pages;
2941 struct btrfs_ordered_extent *ordered;
2942 struct btrfs_trans_handle *trans;
2943
2944 ra = kzalloc(sizeof(*ra), GFP_NOFS);
2945
2946 mutex_lock(&inode->i_mutex);
2947 i = start >> PAGE_CACHE_SHIFT;
2948 last_index = (start + len - 1) >> PAGE_CACHE_SHIFT;
2949
2950 ra_pages = BTRFS_I(inode)->root->fs_info->bdi.ra_pages;
2951
2952 file_ra_state_init(ra, inode->i_mapping);
2953
2954 for (; i <= last_index; i++) {
2955 if (total_read % ra_pages == 0) {
2956 btrfs_force_ra(inode->i_mapping, ra, NULL, i,
2957 calc_ra(i, last_index, ra_pages));
2958 }
2959 total_read++;
2960 again:
2961 if (((u64)i << PAGE_CACHE_SHIFT) > i_size_read(inode))
2962 goto truncate_racing;
2963 page = grab_cache_page(inode->i_mapping, i);
2964 if (!page) {
2965 goto out_unlock;
2966 }
2967 if (!PageUptodate(page)) {
2968 btrfs_readpage(NULL, page);
2969 lock_page(page);
2970 if (!PageUptodate(page)) {
2971 unlock_page(page);
2972 page_cache_release(page);
2973 goto out_unlock;
2974 }
2975 }
2976 wait_on_page_writeback(page);
2977
2978 page_start = (u64)page->index << PAGE_CACHE_SHIFT;
2979 page_end = page_start + PAGE_CACHE_SIZE - 1;
2980 lock_extent(io_tree, page_start, page_end, GFP_NOFS);
2981
2982 ordered = btrfs_lookup_ordered_extent(inode, page_start);
2983 if (ordered) {
2984 unlock_extent(io_tree, page_start, page_end, GFP_NOFS);
2985 unlock_page(page);
2986 page_cache_release(page);
2987 btrfs_start_ordered_extent(inode, ordered, 1);
2988 btrfs_put_ordered_extent(ordered);
2989 goto again;
2990 }
2991 set_page_extent_mapped(page);
2992
2993 /*
2994 * make sure page_mkwrite is called for this page if userland
2995 * wants to change it from mmap
2996 */
2997 clear_page_dirty_for_io(page);
2998
2999 btrfs_set_extent_delalloc(inode, page_start, page_end);
3000 set_page_dirty(page);
3001
3002 unlock_extent(io_tree, page_start, page_end, GFP_NOFS);
3003 unlock_page(page);
3004 page_cache_release(page);
3005 }
3006
3007 out_unlock:
3008 /* we have to start the IO in order to get the ordered extents
3009 * instantiated. This allows the relocation to code to wait
3010 * for all the ordered extents to hit the disk.
3011 *
3012 * Otherwise, it would constantly loop over the same extents
3013 * because the old ones don't get deleted until the IO is
3014 * started
3015 */
3016 btrfs_fdatawrite_range(inode->i_mapping, start, start + len - 1,
3017 WB_SYNC_NONE);
3018 kfree(ra);
3019 trans = btrfs_start_transaction(BTRFS_I(inode)->root, 1);
3020 if (trans) {
3021 btrfs_end_transaction(trans, BTRFS_I(inode)->root);
3022 mark_inode_dirty(inode);
3023 }
3024 mutex_unlock(&inode->i_mutex);
3025 return 0;
3026
3027 truncate_racing:
3028 vmtruncate(inode, inode->i_size);
3029 balance_dirty_pages_ratelimited_nr(inode->i_mapping,
3030 total_read);
3031 goto out_unlock;
3032 }
3033
3034 /*
3035 * The back references tell us which tree holds a ref on a block,
3036 * but it is possible for the tree root field in the reference to
3037 * reflect the original root before a snapshot was made. In this
3038 * case we should search through all the children of a given root
3039 * to find potential holders of references on a block.
3040 *
3041 * Instead, we do something a little less fancy and just search
3042 * all the roots for a given key/block combination.
3043 */
3044 static int find_root_for_ref(struct btrfs_root *root,
3045 struct btrfs_path *path,
3046 struct btrfs_key *key0,
3047 int level,
3048 int file_key,
3049 struct btrfs_root **found_root,
3050 u64 bytenr)
3051 {
3052 struct btrfs_key root_location;
3053 struct btrfs_root *cur_root = *found_root;
3054 struct btrfs_file_extent_item *file_extent;
3055 u64 root_search_start = BTRFS_FS_TREE_OBJECTID;
3056 u64 found_bytenr;
3057 int ret;
3058
3059 root_location.offset = (u64)-1;
3060 root_location.type = BTRFS_ROOT_ITEM_KEY;
3061 path->lowest_level = level;
3062 path->reada = 0;
3063 while(1) {
3064 ret = btrfs_search_slot(NULL, cur_root, key0, path, 0, 0);
3065 found_bytenr = 0;
3066 if (ret == 0 && file_key) {
3067 struct extent_buffer *leaf = path->nodes[0];
3068 file_extent = btrfs_item_ptr(leaf, path->slots[0],
3069 struct btrfs_file_extent_item);
3070 if (btrfs_file_extent_type(leaf, file_extent) ==
3071 BTRFS_FILE_EXTENT_REG) {
3072 found_bytenr =
3073 btrfs_file_extent_disk_bytenr(leaf,
3074 file_extent);
3075 }
3076 } else if (!file_key) {
3077 if (path->nodes[level])
3078 found_bytenr = path->nodes[level]->start;
3079 }
3080
3081 btrfs_release_path(cur_root, path);
3082
3083 if (found_bytenr == bytenr) {
3084 *found_root = cur_root;
3085 ret = 0;
3086 goto out;
3087 }
3088 ret = btrfs_search_root(root->fs_info->tree_root,
3089 root_search_start, &root_search_start);
3090 if (ret)
3091 break;
3092
3093 root_location.objectid = root_search_start;
3094 cur_root = btrfs_read_fs_root_no_name(root->fs_info,
3095 &root_location);
3096 if (!cur_root) {
3097 ret = 1;
3098 break;
3099 }
3100 }
3101 out:
3102 path->lowest_level = 0;
3103 return ret;
3104 }
3105
3106 /*
3107 * note, this releases the path
3108 */
3109 static int noinline relocate_one_reference(struct btrfs_root *extent_root,
3110 struct btrfs_path *path,
3111 struct btrfs_key *extent_key,
3112 u64 *last_file_objectid,
3113 u64 *last_file_offset,
3114 u64 *last_file_root,
3115 u64 last_extent)
3116 {
3117 struct inode *inode;
3118 struct btrfs_root *found_root;
3119 struct btrfs_key root_location;
3120 struct btrfs_key found_key;
3121 struct btrfs_extent_ref *ref;
3122 u64 ref_root;
3123 u64 ref_gen;
3124 u64 ref_objectid;
3125 u64 ref_offset;
3126 int ret;
3127 int level;
3128
3129 WARN_ON(!mutex_is_locked(&extent_root->fs_info->alloc_mutex));
3130
3131 ref = btrfs_item_ptr(path->nodes[0], path->slots[0],
3132 struct btrfs_extent_ref);
3133 ref_root = btrfs_ref_root(path->nodes[0], ref);
3134 ref_gen = btrfs_ref_generation(path->nodes[0], ref);
3135 ref_objectid = btrfs_ref_objectid(path->nodes[0], ref);
3136 ref_offset = btrfs_ref_offset(path->nodes[0], ref);
3137 btrfs_release_path(extent_root, path);
3138
3139 root_location.objectid = ref_root;
3140 if (ref_gen == 0)
3141 root_location.offset = 0;
3142 else
3143 root_location.offset = (u64)-1;
3144 root_location.type = BTRFS_ROOT_ITEM_KEY;
3145
3146 found_root = btrfs_read_fs_root_no_name(extent_root->fs_info,
3147 &root_location);
3148 BUG_ON(!found_root);
3149 mutex_unlock(&extent_root->fs_info->alloc_mutex);
3150
3151 if (ref_objectid >= BTRFS_FIRST_FREE_OBJECTID) {
3152 found_key.objectid = ref_objectid;
3153 found_key.type = BTRFS_EXTENT_DATA_KEY;
3154 found_key.offset = ref_offset;
3155 level = 0;
3156
3157 if (last_extent == extent_key->objectid &&
3158 *last_file_objectid == ref_objectid &&
3159 *last_file_offset == ref_offset &&
3160 *last_file_root == ref_root)
3161 goto out;
3162
3163 ret = find_root_for_ref(extent_root, path, &found_key,
3164 level, 1, &found_root,
3165 extent_key->objectid);
3166
3167 if (ret)
3168 goto out;
3169
3170 if (last_extent == extent_key->objectid &&
3171 *last_file_objectid == ref_objectid &&
3172 *last_file_offset == ref_offset &&
3173 *last_file_root == ref_root)
3174 goto out;
3175
3176 inode = btrfs_iget_locked(extent_root->fs_info->sb,
3177 ref_objectid, found_root);
3178 if (inode->i_state & I_NEW) {
3179 /* the inode and parent dir are two different roots */
3180 BTRFS_I(inode)->root = found_root;
3181 BTRFS_I(inode)->location.objectid = ref_objectid;
3182 BTRFS_I(inode)->location.type = BTRFS_INODE_ITEM_KEY;
3183 BTRFS_I(inode)->location.offset = 0;
3184 btrfs_read_locked_inode(inode);
3185 unlock_new_inode(inode);
3186
3187 }
3188 /* this can happen if the reference is not against
3189 * the latest version of the tree root
3190 */
3191 if (is_bad_inode(inode))
3192 goto out;
3193
3194 *last_file_objectid = inode->i_ino;
3195 *last_file_root = found_root->root_key.objectid;
3196 *last_file_offset = ref_offset;
3197
3198 relocate_inode_pages(inode, ref_offset, extent_key->offset);
3199 iput(inode);
3200 } else {
3201 struct btrfs_trans_handle *trans;
3202 struct extent_buffer *eb;
3203 int needs_lock = 0;
3204
3205 eb = read_tree_block(found_root, extent_key->objectid,
3206 extent_key->offset, 0);
3207 btrfs_tree_lock(eb);
3208 level = btrfs_header_level(eb);
3209
3210 if (level == 0)
3211 btrfs_item_key_to_cpu(eb, &found_key, 0);
3212 else
3213 btrfs_node_key_to_cpu(eb, &found_key, 0);
3214
3215 btrfs_tree_unlock(eb);
3216 free_extent_buffer(eb);
3217
3218 ret = find_root_for_ref(extent_root, path, &found_key,
3219 level, 0, &found_root,
3220 extent_key->objectid);
3221
3222 if (ret)
3223 goto out;
3224
3225 /*
3226 * right here almost anything could happen to our key,
3227 * but that's ok. The cow below will either relocate it
3228 * or someone else will have relocated it. Either way,
3229 * it is in a different spot than it was before and
3230 * we're happy.
3231 */
3232
3233 trans = btrfs_start_transaction(found_root, 1);
3234
3235 if (found_root == extent_root->fs_info->extent_root ||
3236 found_root == extent_root->fs_info->chunk_root ||
3237 found_root == extent_root->fs_info->dev_root) {
3238 needs_lock = 1;
3239 mutex_lock(&extent_root->fs_info->alloc_mutex);
3240 }
3241
3242 path->lowest_level = level;
3243 path->reada = 2;
3244 ret = btrfs_search_slot(trans, found_root, &found_key, path,
3245 0, 1);
3246 path->lowest_level = 0;
3247 btrfs_release_path(found_root, path);
3248
3249 if (found_root == found_root->fs_info->extent_root)
3250 btrfs_extent_post_op(trans, found_root);
3251 if (needs_lock)
3252 mutex_unlock(&extent_root->fs_info->alloc_mutex);
3253
3254 btrfs_end_transaction(trans, found_root);
3255
3256 }
3257 out:
3258 mutex_lock(&extent_root->fs_info->alloc_mutex);
3259 return 0;
3260 }
3261
3262 static int noinline del_extent_zero(struct btrfs_root *extent_root,
3263 struct btrfs_path *path,
3264 struct btrfs_key *extent_key)
3265 {
3266 int ret;
3267 struct btrfs_trans_handle *trans;
3268
3269 trans = btrfs_start_transaction(extent_root, 1);
3270 ret = btrfs_search_slot(trans, extent_root, extent_key, path, -1, 1);
3271 if (ret > 0) {
3272 ret = -EIO;
3273 goto out;
3274 }
3275 if (ret < 0)
3276 goto out;
3277 ret = btrfs_del_item(trans, extent_root, path);
3278 out:
3279 btrfs_end_transaction(trans, extent_root);
3280 return ret;
3281 }
3282
3283 static int noinline relocate_one_extent(struct btrfs_root *extent_root,
3284 struct btrfs_path *path,
3285 struct btrfs_key *extent_key)
3286 {
3287 struct btrfs_key key;
3288 struct btrfs_key found_key;
3289 struct extent_buffer *leaf;
3290 u64 last_file_objectid = 0;
3291 u64 last_file_root = 0;
3292 u64 last_file_offset = (u64)-1;
3293 u64 last_extent = 0;
3294 u32 nritems;
3295 u32 item_size;
3296 int ret = 0;
3297
3298 if (extent_key->objectid == 0) {
3299 ret = del_extent_zero(extent_root, path, extent_key);
3300 goto out;
3301 }
3302 key.objectid = extent_key->objectid;
3303 key.type = BTRFS_EXTENT_REF_KEY;
3304 key.offset = 0;
3305
3306 while(1) {
3307 ret = btrfs_search_slot(NULL, extent_root, &key, path, 0, 0);
3308
3309 if (ret < 0)
3310 goto out;
3311
3312 ret = 0;
3313 leaf = path->nodes[0];
3314 nritems = btrfs_header_nritems(leaf);
3315 if (path->slots[0] == nritems) {
3316 ret = btrfs_next_leaf(extent_root, path);
3317 if (ret > 0) {
3318 ret = 0;
3319 goto out;
3320 }
3321 if (ret < 0)
3322 goto out;
3323 leaf = path->nodes[0];
3324 }
3325
3326 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
3327 if (found_key.objectid != extent_key->objectid) {
3328 break;
3329 }
3330
3331 if (found_key.type != BTRFS_EXTENT_REF_KEY) {
3332 break;
3333 }
3334
3335 key.offset = found_key.offset + 1;
3336 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
3337
3338 ret = relocate_one_reference(extent_root, path, extent_key,
3339 &last_file_objectid,
3340 &last_file_offset,
3341 &last_file_root, last_extent);
3342 if (ret)
3343 goto out;
3344 last_extent = extent_key->objectid;
3345 }
3346 ret = 0;
3347 out:
3348 btrfs_release_path(extent_root, path);
3349 return ret;
3350 }
3351
3352 static u64 update_block_group_flags(struct btrfs_root *root, u64 flags)
3353 {
3354 u64 num_devices;
3355 u64 stripped = BTRFS_BLOCK_GROUP_RAID0 |
3356 BTRFS_BLOCK_GROUP_RAID1 | BTRFS_BLOCK_GROUP_RAID10;
3357
3358 num_devices = root->fs_info->fs_devices->num_devices;
3359 if (num_devices == 1) {
3360 stripped |= BTRFS_BLOCK_GROUP_DUP;
3361 stripped = flags & ~stripped;
3362
3363 /* turn raid0 into single device chunks */
3364 if (flags & BTRFS_BLOCK_GROUP_RAID0)
3365 return stripped;
3366
3367 /* turn mirroring into duplication */
3368 if (flags & (BTRFS_BLOCK_GROUP_RAID1 |
3369 BTRFS_BLOCK_GROUP_RAID10))
3370 return stripped | BTRFS_BLOCK_GROUP_DUP;
3371 return flags;
3372 } else {
3373 /* they already had raid on here, just return */
3374 if (flags & stripped)
3375 return flags;
3376
3377 stripped |= BTRFS_BLOCK_GROUP_DUP;
3378 stripped = flags & ~stripped;
3379
3380 /* switch duplicated blocks with raid1 */
3381 if (flags & BTRFS_BLOCK_GROUP_DUP)
3382 return stripped | BTRFS_BLOCK_GROUP_RAID1;
3383
3384 /* turn single device chunks into raid0 */
3385 return stripped | BTRFS_BLOCK_GROUP_RAID0;
3386 }
3387 return flags;
3388 }
3389
3390 int __alloc_chunk_for_shrink(struct btrfs_root *root,
3391 struct btrfs_block_group_cache *shrink_block_group,
3392 int force)
3393 {
3394 struct btrfs_trans_handle *trans;
3395 u64 new_alloc_flags;
3396 u64 calc;
3397
3398 spin_lock(&shrink_block_group->lock);
3399 if (btrfs_block_group_used(&shrink_block_group->item) > 0) {
3400 spin_unlock(&shrink_block_group->lock);
3401 mutex_unlock(&root->fs_info->alloc_mutex);
3402
3403 trans = btrfs_start_transaction(root, 1);
3404 mutex_lock(&root->fs_info->alloc_mutex);
3405 spin_lock(&shrink_block_group->lock);
3406
3407 new_alloc_flags = update_block_group_flags(root,
3408 shrink_block_group->flags);
3409 if (new_alloc_flags != shrink_block_group->flags) {
3410 calc =
3411 btrfs_block_group_used(&shrink_block_group->item);
3412 } else {
3413 calc = shrink_block_group->key.offset;
3414 }
3415 spin_unlock(&shrink_block_group->lock);
3416
3417 do_chunk_alloc(trans, root->fs_info->extent_root,
3418 calc + 2 * 1024 * 1024, new_alloc_flags, force);
3419
3420 mutex_unlock(&root->fs_info->alloc_mutex);
3421 btrfs_end_transaction(trans, root);
3422 mutex_lock(&root->fs_info->alloc_mutex);
3423 } else
3424 spin_unlock(&shrink_block_group->lock);
3425 return 0;
3426 }
3427
3428 int btrfs_shrink_extent_tree(struct btrfs_root *root, u64 shrink_start)
3429 {
3430 struct btrfs_trans_handle *trans;
3431 struct btrfs_root *tree_root = root->fs_info->tree_root;
3432 struct btrfs_path *path;
3433 u64 cur_byte;
3434 u64 total_found;
3435 u64 shrink_last_byte;
3436 struct btrfs_block_group_cache *shrink_block_group;
3437 struct btrfs_key key;
3438 struct btrfs_key found_key;
3439 struct extent_buffer *leaf;
3440 u32 nritems;
3441 int ret;
3442 int progress;
3443
3444 mutex_lock(&root->fs_info->alloc_mutex);
3445 shrink_block_group = btrfs_lookup_block_group(root->fs_info,
3446 shrink_start);
3447 BUG_ON(!shrink_block_group);
3448
3449 shrink_last_byte = shrink_block_group->key.objectid +
3450 shrink_block_group->key.offset;
3451
3452 shrink_block_group->space_info->total_bytes -=
3453 shrink_block_group->key.offset;
3454 path = btrfs_alloc_path();
3455 root = root->fs_info->extent_root;
3456 path->reada = 2;
3457
3458 printk("btrfs relocating block group %llu flags %llu\n",
3459 (unsigned long long)shrink_start,
3460 (unsigned long long)shrink_block_group->flags);
3461
3462 __alloc_chunk_for_shrink(root, shrink_block_group, 1);
3463
3464 again:
3465
3466 shrink_block_group->ro = 1;
3467
3468 total_found = 0;
3469 progress = 0;
3470 key.objectid = shrink_start;
3471 key.offset = 0;
3472 key.type = 0;
3473 cur_byte = key.objectid;
3474
3475 mutex_unlock(&root->fs_info->alloc_mutex);
3476
3477 btrfs_start_delalloc_inodes(root);
3478 btrfs_wait_ordered_extents(tree_root, 0);
3479
3480 mutex_lock(&root->fs_info->alloc_mutex);
3481
3482 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
3483 if (ret < 0)
3484 goto out;
3485
3486 ret = btrfs_previous_item(root, path, 0, BTRFS_EXTENT_ITEM_KEY);
3487 if (ret < 0)
3488 goto out;
3489
3490 if (ret == 0) {
3491 leaf = path->nodes[0];
3492 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
3493 if (found_key.objectid + found_key.offset > shrink_start &&
3494 found_key.objectid < shrink_last_byte) {
3495 cur_byte = found_key.objectid;
3496 key.objectid = cur_byte;
3497 }
3498 }
3499 btrfs_release_path(root, path);
3500
3501 while(1) {
3502 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
3503 if (ret < 0)
3504 goto out;
3505
3506 next:
3507 leaf = path->nodes[0];
3508 nritems = btrfs_header_nritems(leaf);
3509 if (path->slots[0] >= nritems) {
3510 ret = btrfs_next_leaf(root, path);
3511 if (ret < 0)
3512 goto out;
3513 if (ret == 1) {
3514 ret = 0;
3515 break;
3516 }
3517 leaf = path->nodes[0];
3518 nritems = btrfs_header_nritems(leaf);
3519 }
3520
3521 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
3522
3523 if (found_key.objectid >= shrink_last_byte)
3524 break;
3525
3526 if (progress && need_resched()) {
3527 memcpy(&key, &found_key, sizeof(key));
3528 cond_resched();
3529 btrfs_release_path(root, path);
3530 btrfs_search_slot(NULL, root, &key, path, 0, 0);
3531 progress = 0;
3532 goto next;
3533 }
3534 progress = 1;
3535
3536 if (btrfs_key_type(&found_key) != BTRFS_EXTENT_ITEM_KEY ||
3537 found_key.objectid + found_key.offset <= cur_byte) {
3538 memcpy(&key, &found_key, sizeof(key));
3539 key.offset++;
3540 path->slots[0]++;
3541 goto next;
3542 }
3543
3544 total_found++;
3545 cur_byte = found_key.objectid + found_key.offset;
3546 key.objectid = cur_byte;
3547 btrfs_release_path(root, path);
3548 ret = relocate_one_extent(root, path, &found_key);
3549 __alloc_chunk_for_shrink(root, shrink_block_group, 0);
3550 }
3551
3552 btrfs_release_path(root, path);
3553
3554 if (total_found > 0) {
3555 printk("btrfs relocate found %llu last extent was %llu\n",
3556 (unsigned long long)total_found,
3557 (unsigned long long)found_key.objectid);
3558 mutex_unlock(&root->fs_info->alloc_mutex);
3559 trans = btrfs_start_transaction(tree_root, 1);
3560 btrfs_commit_transaction(trans, tree_root);
3561
3562 btrfs_clean_old_snapshots(tree_root);
3563
3564 btrfs_start_delalloc_inodes(root);
3565 btrfs_wait_ordered_extents(tree_root, 0);
3566
3567 trans = btrfs_start_transaction(tree_root, 1);
3568 btrfs_commit_transaction(trans, tree_root);
3569 mutex_lock(&root->fs_info->alloc_mutex);
3570 goto again;
3571 }
3572
3573 /*
3574 * we've freed all the extents, now remove the block
3575 * group item from the tree
3576 */
3577 mutex_unlock(&root->fs_info->alloc_mutex);
3578
3579 trans = btrfs_start_transaction(root, 1);
3580
3581 mutex_lock(&root->fs_info->alloc_mutex);
3582 memcpy(&key, &shrink_block_group->key, sizeof(key));
3583
3584 ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
3585 if (ret > 0)
3586 ret = -EIO;
3587 if (ret < 0) {
3588 btrfs_end_transaction(trans, root);
3589 goto out;
3590 }
3591
3592 spin_lock(&root->fs_info->block_group_cache_lock);
3593 rb_erase(&shrink_block_group->cache_node,
3594 &root->fs_info->block_group_cache_tree);
3595 spin_unlock(&root->fs_info->block_group_cache_lock);
3596
3597 ret = btrfs_remove_free_space(shrink_block_group, key.objectid,
3598 key.offset);
3599 if (ret) {
3600 btrfs_end_transaction(trans, root);
3601 goto out;
3602 }
3603 /*
3604 memset(shrink_block_group, 0, sizeof(*shrink_block_group));
3605 kfree(shrink_block_group);
3606 */
3607
3608 btrfs_del_item(trans, root, path);
3609 btrfs_release_path(root, path);
3610 mutex_unlock(&root->fs_info->alloc_mutex);
3611 btrfs_commit_transaction(trans, root);
3612
3613 mutex_lock(&root->fs_info->alloc_mutex);
3614
3615 /* the code to unpin extents might set a few bits in the free
3616 * space cache for this range again
3617 */
3618 /* XXX? */
3619 ret = btrfs_remove_free_space(shrink_block_group, key.objectid,
3620 key.offset);
3621 out:
3622 btrfs_free_path(path);
3623 mutex_unlock(&root->fs_info->alloc_mutex);
3624 return ret;
3625 }
3626
3627 int find_first_block_group(struct btrfs_root *root, struct btrfs_path *path,
3628 struct btrfs_key *key)
3629 {
3630 int ret = 0;
3631 struct btrfs_key found_key;
3632 struct extent_buffer *leaf;
3633 int slot;
3634
3635 ret = btrfs_search_slot(NULL, root, key, path, 0, 0);
3636 if (ret < 0)
3637 goto out;
3638
3639 while(1) {
3640 slot = path->slots[0];
3641 leaf = path->nodes[0];
3642 if (slot >= btrfs_header_nritems(leaf)) {
3643 ret = btrfs_next_leaf(root, path);
3644 if (ret == 0)
3645 continue;
3646 if (ret < 0)
3647 goto out;
3648 break;
3649 }
3650 btrfs_item_key_to_cpu(leaf, &found_key, slot);
3651
3652 if (found_key.objectid >= key->objectid &&
3653 found_key.type == BTRFS_BLOCK_GROUP_ITEM_KEY) {
3654 ret = 0;
3655 goto out;
3656 }
3657 path->slots[0]++;
3658 }
3659 ret = -ENOENT;
3660 out:
3661 return ret;
3662 }
3663
3664 int btrfs_read_block_groups(struct btrfs_root *root)
3665 {
3666 struct btrfs_path *path;
3667 int ret;
3668 struct btrfs_block_group_cache *cache;
3669 struct btrfs_fs_info *info = root->fs_info;
3670 struct btrfs_space_info *space_info;
3671 struct btrfs_key key;
3672 struct btrfs_key found_key;
3673 struct extent_buffer *leaf;
3674
3675 root = info->extent_root;
3676 key.objectid = 0;
3677 key.offset = 0;
3678 btrfs_set_key_type(&key, BTRFS_BLOCK_GROUP_ITEM_KEY);
3679 path = btrfs_alloc_path();
3680 if (!path)
3681 return -ENOMEM;
3682
3683 mutex_lock(&root->fs_info->alloc_mutex);
3684 while(1) {
3685 ret = find_first_block_group(root, path, &key);
3686 if (ret > 0) {
3687 ret = 0;
3688 goto error;
3689 }
3690 if (ret != 0)
3691 goto error;
3692
3693 leaf = path->nodes[0];
3694 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
3695 cache = kzalloc(sizeof(*cache), GFP_NOFS);
3696 if (!cache) {
3697 ret = -ENOMEM;
3698 break;
3699 }
3700
3701 spin_lock_init(&cache->lock);
3702 INIT_LIST_HEAD(&cache->list);
3703 read_extent_buffer(leaf, &cache->item,
3704 btrfs_item_ptr_offset(leaf, path->slots[0]),
3705 sizeof(cache->item));
3706 memcpy(&cache->key, &found_key, sizeof(found_key));
3707
3708 key.objectid = found_key.objectid + found_key.offset;
3709 btrfs_release_path(root, path);
3710 cache->flags = btrfs_block_group_flags(&cache->item);
3711
3712 ret = update_space_info(info, cache->flags, found_key.offset,
3713 btrfs_block_group_used(&cache->item),
3714 &space_info);
3715 BUG_ON(ret);
3716 cache->space_info = space_info;
3717 spin_lock(&space_info->lock);
3718 list_add(&cache->list, &space_info->block_groups);
3719 spin_unlock(&space_info->lock);
3720
3721 ret = btrfs_add_block_group_cache(root->fs_info, cache);
3722 BUG_ON(ret);
3723
3724 if (key.objectid >=
3725 btrfs_super_total_bytes(&info->super_copy))
3726 break;
3727 }
3728 ret = 0;
3729 error:
3730 btrfs_free_path(path);
3731 mutex_unlock(&root->fs_info->alloc_mutex);
3732 return ret;
3733 }
3734
3735 int btrfs_make_block_group(struct btrfs_trans_handle *trans,
3736 struct btrfs_root *root, u64 bytes_used,
3737 u64 type, u64 chunk_objectid, u64 chunk_offset,
3738 u64 size)
3739 {
3740 int ret;
3741 struct btrfs_root *extent_root;
3742 struct btrfs_block_group_cache *cache;
3743
3744 WARN_ON(!mutex_is_locked(&root->fs_info->alloc_mutex));
3745 extent_root = root->fs_info->extent_root;
3746
3747 root->fs_info->last_trans_new_blockgroup = trans->transid;
3748
3749 cache = kzalloc(sizeof(*cache), GFP_NOFS);
3750 if (!cache)
3751 return -ENOMEM;
3752
3753 cache->key.objectid = chunk_offset;
3754 cache->key.offset = size;
3755 spin_lock_init(&cache->lock);
3756 INIT_LIST_HEAD(&cache->list);
3757 btrfs_set_key_type(&cache->key, BTRFS_BLOCK_GROUP_ITEM_KEY);
3758
3759 btrfs_set_block_group_used(&cache->item, bytes_used);
3760 btrfs_set_block_group_chunk_objectid(&cache->item, chunk_objectid);
3761 cache->flags = type;
3762 btrfs_set_block_group_flags(&cache->item, type);
3763
3764 ret = update_space_info(root->fs_info, cache->flags, size, bytes_used,
3765 &cache->space_info);
3766 BUG_ON(ret);
3767 spin_lock(&cache->space_info->lock);
3768 list_add(&cache->list, &cache->space_info->block_groups);
3769 spin_unlock(&cache->space_info->lock);
3770
3771 ret = btrfs_add_block_group_cache(root->fs_info, cache);
3772 BUG_ON(ret);
3773
3774 ret = btrfs_insert_item(trans, extent_root, &cache->key, &cache->item,
3775 sizeof(cache->item));
3776 BUG_ON(ret);
3777
3778 finish_current_insert(trans, extent_root);
3779 ret = del_pending_extents(trans, extent_root);
3780 BUG_ON(ret);
3781 set_avail_alloc_bits(extent_root->fs_info, type);
3782
3783 return 0;
3784 }
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