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Btrfs: Deal with failed writes in mirrored configurations
[deliverable/linux.git] / fs / btrfs / extent-tree.c
1 /*
2 * Copyright (C) 2007 Oracle. All rights reserved.
3 *
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU General Public
6 * License v2 as published by the Free Software Foundation.
7 *
8 * This program is distributed in the hope that it will be useful,
9 * but WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
11 * General Public License for more details.
12 *
13 * You should have received a copy of the GNU General Public
14 * License along with this program; if not, write to the
15 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
16 * Boston, MA 021110-1307, USA.
17 */
18 #include <linux/sched.h>
19 #include <linux/pagemap.h>
20 #include <linux/writeback.h>
21 #include "hash.h"
22 #include "crc32c.h"
23 #include "ctree.h"
24 #include "disk-io.h"
25 #include "print-tree.h"
26 #include "transaction.h"
27 #include "volumes.h"
28
29 #define BLOCK_GROUP_DATA EXTENT_WRITEBACK
30 #define BLOCK_GROUP_METADATA EXTENT_UPTODATE
31 #define BLOCK_GROUP_SYSTEM EXTENT_NEW
32
33 #define BLOCK_GROUP_DIRTY EXTENT_DIRTY
34
35 static int finish_current_insert(struct btrfs_trans_handle *trans, struct
36 btrfs_root *extent_root);
37 static int del_pending_extents(struct btrfs_trans_handle *trans, struct
38 btrfs_root *extent_root);
39
40
41 static int cache_block_group(struct btrfs_root *root,
42 struct btrfs_block_group_cache *block_group)
43 {
44 struct btrfs_path *path;
45 int ret;
46 struct btrfs_key key;
47 struct extent_buffer *leaf;
48 struct extent_io_tree *free_space_cache;
49 int slot;
50 u64 last = 0;
51 u64 hole_size;
52 u64 first_free;
53 int found = 0;
54
55 if (!block_group)
56 return 0;
57
58 root = root->fs_info->extent_root;
59 free_space_cache = &root->fs_info->free_space_cache;
60
61 if (block_group->cached)
62 return 0;
63
64 path = btrfs_alloc_path();
65 if (!path)
66 return -ENOMEM;
67
68 path->reada = 2;
69 first_free = block_group->key.objectid;
70 key.objectid = block_group->key.objectid;
71 key.offset = 0;
72 btrfs_set_key_type(&key, BTRFS_EXTENT_ITEM_KEY);
73 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
74 if (ret < 0)
75 return ret;
76 ret = btrfs_previous_item(root, path, 0, BTRFS_EXTENT_ITEM_KEY);
77 if (ret < 0)
78 return ret;
79 if (ret == 0) {
80 leaf = path->nodes[0];
81 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
82 if (key.objectid + key.offset > first_free)
83 first_free = key.objectid + key.offset;
84 }
85 while(1) {
86 leaf = path->nodes[0];
87 slot = path->slots[0];
88 if (slot >= btrfs_header_nritems(leaf)) {
89 ret = btrfs_next_leaf(root, path);
90 if (ret < 0)
91 goto err;
92 if (ret == 0) {
93 continue;
94 } else {
95 break;
96 }
97 }
98 btrfs_item_key_to_cpu(leaf, &key, slot);
99 if (key.objectid < block_group->key.objectid) {
100 goto next;
101 }
102 if (key.objectid >= block_group->key.objectid +
103 block_group->key.offset) {
104 break;
105 }
106
107 if (btrfs_key_type(&key) == BTRFS_EXTENT_ITEM_KEY) {
108 if (!found) {
109 last = first_free;
110 found = 1;
111 }
112 if (key.objectid > last) {
113 hole_size = key.objectid - last;
114 set_extent_dirty(free_space_cache, last,
115 last + hole_size - 1,
116 GFP_NOFS);
117 }
118 last = key.objectid + key.offset;
119 }
120 next:
121 path->slots[0]++;
122 }
123
124 if (!found)
125 last = first_free;
126 if (block_group->key.objectid +
127 block_group->key.offset > last) {
128 hole_size = block_group->key.objectid +
129 block_group->key.offset - last;
130 set_extent_dirty(free_space_cache, last,
131 last + hole_size - 1, GFP_NOFS);
132 }
133 block_group->cached = 1;
134 err:
135 btrfs_free_path(path);
136 return 0;
137 }
138
139 struct btrfs_block_group_cache *btrfs_lookup_block_group(struct
140 btrfs_fs_info *info,
141 u64 bytenr)
142 {
143 struct extent_io_tree *block_group_cache;
144 struct btrfs_block_group_cache *block_group = NULL;
145 u64 ptr;
146 u64 start;
147 u64 end;
148 int ret;
149
150 block_group_cache = &info->block_group_cache;
151 ret = find_first_extent_bit(block_group_cache,
152 bytenr, &start, &end,
153 BLOCK_GROUP_DATA | BLOCK_GROUP_METADATA |
154 BLOCK_GROUP_SYSTEM);
155 if (ret) {
156 return NULL;
157 }
158 ret = get_state_private(block_group_cache, start, &ptr);
159 if (ret)
160 return NULL;
161
162 block_group = (struct btrfs_block_group_cache *)(unsigned long)ptr;
163 if (block_group->key.objectid <= bytenr && bytenr <
164 block_group->key.objectid + block_group->key.offset)
165 return block_group;
166 return NULL;
167 }
168
169 static int block_group_bits(struct btrfs_block_group_cache *cache, u64 bits)
170 {
171 return (cache->flags & bits) == bits;
172 }
173
174 static int noinline find_search_start(struct btrfs_root *root,
175 struct btrfs_block_group_cache **cache_ret,
176 u64 *start_ret, int num, int data)
177 {
178 int ret;
179 struct btrfs_block_group_cache *cache = *cache_ret;
180 struct extent_io_tree *free_space_cache;
181 struct extent_state *state;
182 u64 last;
183 u64 start = 0;
184 u64 cache_miss = 0;
185 u64 total_fs_bytes;
186 u64 search_start = *start_ret;
187 int wrapped = 0;
188
189 if (!cache)
190 goto out;
191
192 total_fs_bytes = btrfs_super_total_bytes(&root->fs_info->super_copy);
193 free_space_cache = &root->fs_info->free_space_cache;
194
195 again:
196 ret = cache_block_group(root, cache);
197 if (ret)
198 goto out;
199
200 last = max(search_start, cache->key.objectid);
201 if (!block_group_bits(cache, data) || cache->ro) {
202 goto new_group;
203 }
204
205 spin_lock_irq(&free_space_cache->lock);
206 state = find_first_extent_bit_state(free_space_cache, last, EXTENT_DIRTY);
207 while(1) {
208 if (!state) {
209 if (!cache_miss)
210 cache_miss = last;
211 spin_unlock_irq(&free_space_cache->lock);
212 goto new_group;
213 }
214
215 start = max(last, state->start);
216 last = state->end + 1;
217 if (last - start < num) {
218 if (last == cache->key.objectid + cache->key.offset)
219 cache_miss = start;
220 do {
221 state = extent_state_next(state);
222 } while(state && !(state->state & EXTENT_DIRTY));
223 continue;
224 }
225 spin_unlock_irq(&free_space_cache->lock);
226 if (cache->ro)
227 goto new_group;
228 if (start + num > cache->key.objectid + cache->key.offset)
229 goto new_group;
230 if (start + num > total_fs_bytes)
231 goto new_group;
232 if (!block_group_bits(cache, data)) {
233 printk("block group bits don't match %Lu %d\n", cache->flags, data);
234 }
235 *start_ret = start;
236 return 0;
237 }
238 out:
239 cache = btrfs_lookup_block_group(root->fs_info, search_start);
240 if (!cache) {
241 printk("Unable to find block group for %Lu\n", search_start);
242 WARN_ON(1);
243 }
244 return -ENOSPC;
245
246 new_group:
247 last = cache->key.objectid + cache->key.offset;
248 wrapped:
249 cache = btrfs_lookup_block_group(root->fs_info, last);
250 if (!cache || cache->key.objectid >= total_fs_bytes) {
251 no_cache:
252 if (!wrapped) {
253 wrapped = 1;
254 last = search_start;
255 goto wrapped;
256 }
257 goto out;
258 }
259 if (cache_miss && !cache->cached) {
260 cache_block_group(root, cache);
261 last = cache_miss;
262 cache = btrfs_lookup_block_group(root->fs_info, last);
263 }
264 cache = btrfs_find_block_group(root, cache, last, data, 0);
265 if (!cache)
266 goto no_cache;
267 *cache_ret = cache;
268 cache_miss = 0;
269 goto again;
270 }
271
272 static u64 div_factor(u64 num, int factor)
273 {
274 if (factor == 10)
275 return num;
276 num *= factor;
277 do_div(num, 10);
278 return num;
279 }
280
281 static int block_group_state_bits(u64 flags)
282 {
283 int bits = 0;
284 if (flags & BTRFS_BLOCK_GROUP_DATA)
285 bits |= BLOCK_GROUP_DATA;
286 if (flags & BTRFS_BLOCK_GROUP_METADATA)
287 bits |= BLOCK_GROUP_METADATA;
288 if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
289 bits |= BLOCK_GROUP_SYSTEM;
290 return bits;
291 }
292
293 struct btrfs_block_group_cache *btrfs_find_block_group(struct btrfs_root *root,
294 struct btrfs_block_group_cache
295 *hint, u64 search_start,
296 int data, int owner)
297 {
298 struct btrfs_block_group_cache *cache;
299 struct extent_io_tree *block_group_cache;
300 struct btrfs_block_group_cache *found_group = NULL;
301 struct btrfs_fs_info *info = root->fs_info;
302 u64 used;
303 u64 last = 0;
304 u64 hint_last;
305 u64 start;
306 u64 end;
307 u64 free_check;
308 u64 ptr;
309 u64 total_fs_bytes;
310 int bit;
311 int ret;
312 int full_search = 0;
313 int factor = 10;
314
315 block_group_cache = &info->block_group_cache;
316 total_fs_bytes = btrfs_super_total_bytes(&root->fs_info->super_copy);
317
318 if (data & BTRFS_BLOCK_GROUP_METADATA)
319 factor = 9;
320
321 bit = block_group_state_bits(data);
322
323 if (search_start && search_start < total_fs_bytes) {
324 struct btrfs_block_group_cache *shint;
325 shint = btrfs_lookup_block_group(info, search_start);
326 if (shint && block_group_bits(shint, data) && !shint->ro) {
327 used = btrfs_block_group_used(&shint->item);
328 if (used + shint->pinned <
329 div_factor(shint->key.offset, factor)) {
330 return shint;
331 }
332 }
333 }
334 if (hint && !hint->ro && block_group_bits(hint, data) &&
335 hint->key.objectid < total_fs_bytes) {
336 used = btrfs_block_group_used(&hint->item);
337 if (used + hint->pinned <
338 div_factor(hint->key.offset, factor)) {
339 return hint;
340 }
341 last = hint->key.objectid + hint->key.offset;
342 hint_last = last;
343 } else {
344 if (hint)
345 hint_last = max(hint->key.objectid, search_start);
346 else
347 hint_last = search_start;
348
349 if (hint_last >= total_fs_bytes)
350 hint_last = search_start;
351 last = hint_last;
352 }
353 again:
354 while(1) {
355 ret = find_first_extent_bit(block_group_cache, last,
356 &start, &end, bit);
357 if (ret)
358 break;
359
360 ret = get_state_private(block_group_cache, start, &ptr);
361 if (ret)
362 break;
363
364 cache = (struct btrfs_block_group_cache *)(unsigned long)ptr;
365 last = cache->key.objectid + cache->key.offset;
366 used = btrfs_block_group_used(&cache->item);
367
368 if (cache->key.objectid > total_fs_bytes)
369 break;
370
371 if (!cache->ro && block_group_bits(cache, data)) {
372 if (full_search)
373 free_check = cache->key.offset;
374 else
375 free_check = div_factor(cache->key.offset,
376 factor);
377
378 if (used + cache->pinned < free_check) {
379 found_group = cache;
380 goto found;
381 }
382 }
383 cond_resched();
384 }
385 if (!full_search) {
386 last = search_start;
387 full_search = 1;
388 goto again;
389 }
390 found:
391 return found_group;
392 }
393
394 static u64 hash_extent_ref(u64 root_objectid, u64 ref_generation,
395 u64 owner, u64 owner_offset)
396 {
397 u32 high_crc = ~(u32)0;
398 u32 low_crc = ~(u32)0;
399 __le64 lenum;
400 lenum = cpu_to_le64(root_objectid);
401 high_crc = btrfs_crc32c(high_crc, &lenum, sizeof(lenum));
402 lenum = cpu_to_le64(ref_generation);
403 low_crc = btrfs_crc32c(low_crc, &lenum, sizeof(lenum));
404 if (owner >= BTRFS_FIRST_FREE_OBJECTID) {
405 lenum = cpu_to_le64(owner);
406 low_crc = btrfs_crc32c(low_crc, &lenum, sizeof(lenum));
407 lenum = cpu_to_le64(owner_offset);
408 low_crc = btrfs_crc32c(low_crc, &lenum, sizeof(lenum));
409 }
410 return ((u64)high_crc << 32) | (u64)low_crc;
411 }
412
413 static int match_extent_ref(struct extent_buffer *leaf,
414 struct btrfs_extent_ref *disk_ref,
415 struct btrfs_extent_ref *cpu_ref)
416 {
417 int ret;
418 int len;
419
420 if (cpu_ref->objectid)
421 len = sizeof(*cpu_ref);
422 else
423 len = 2 * sizeof(u64);
424 ret = memcmp_extent_buffer(leaf, cpu_ref, (unsigned long)disk_ref,
425 len);
426 return ret == 0;
427 }
428
429 static int noinline lookup_extent_backref(struct btrfs_trans_handle *trans,
430 struct btrfs_root *root,
431 struct btrfs_path *path, u64 bytenr,
432 u64 root_objectid,
433 u64 ref_generation, u64 owner,
434 u64 owner_offset, int del)
435 {
436 u64 hash;
437 struct btrfs_key key;
438 struct btrfs_key found_key;
439 struct btrfs_extent_ref ref;
440 struct extent_buffer *leaf;
441 struct btrfs_extent_ref *disk_ref;
442 int ret;
443 int ret2;
444
445 btrfs_set_stack_ref_root(&ref, root_objectid);
446 btrfs_set_stack_ref_generation(&ref, ref_generation);
447 btrfs_set_stack_ref_objectid(&ref, owner);
448 btrfs_set_stack_ref_offset(&ref, owner_offset);
449
450 hash = hash_extent_ref(root_objectid, ref_generation, owner,
451 owner_offset);
452 key.offset = hash;
453 key.objectid = bytenr;
454 key.type = BTRFS_EXTENT_REF_KEY;
455
456 while (1) {
457 ret = btrfs_search_slot(trans, root, &key, path,
458 del ? -1 : 0, del);
459 if (ret < 0)
460 goto out;
461 leaf = path->nodes[0];
462 if (ret != 0) {
463 u32 nritems = btrfs_header_nritems(leaf);
464 if (path->slots[0] >= nritems) {
465 ret2 = btrfs_next_leaf(root, path);
466 if (ret2)
467 goto out;
468 leaf = path->nodes[0];
469 }
470 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
471 if (found_key.objectid != bytenr ||
472 found_key.type != BTRFS_EXTENT_REF_KEY)
473 goto out;
474 key.offset = found_key.offset;
475 if (del) {
476 btrfs_release_path(root, path);
477 continue;
478 }
479 }
480 disk_ref = btrfs_item_ptr(path->nodes[0],
481 path->slots[0],
482 struct btrfs_extent_ref);
483 if (match_extent_ref(path->nodes[0], disk_ref, &ref)) {
484 ret = 0;
485 goto out;
486 }
487 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
488 key.offset = found_key.offset + 1;
489 btrfs_release_path(root, path);
490 }
491 out:
492 return ret;
493 }
494
495 /*
496 * Back reference rules. Back refs have three main goals:
497 *
498 * 1) differentiate between all holders of references to an extent so that
499 * when a reference is dropped we can make sure it was a valid reference
500 * before freeing the extent.
501 *
502 * 2) Provide enough information to quickly find the holders of an extent
503 * if we notice a given block is corrupted or bad.
504 *
505 * 3) Make it easy to migrate blocks for FS shrinking or storage pool
506 * maintenance. This is actually the same as #2, but with a slightly
507 * different use case.
508 *
509 * File extents can be referenced by:
510 *
511 * - multiple snapshots, subvolumes, or different generations in one subvol
512 * - different files inside a single subvolume (in theory, not implemented yet)
513 * - different offsets inside a file (bookend extents in file.c)
514 *
515 * The extent ref structure has fields for:
516 *
517 * - Objectid of the subvolume root
518 * - Generation number of the tree holding the reference
519 * - objectid of the file holding the reference
520 * - offset in the file corresponding to the key holding the reference
521 *
522 * When a file extent is allocated the fields are filled in:
523 * (root_key.objectid, trans->transid, inode objectid, offset in file)
524 *
525 * When a leaf is cow'd new references are added for every file extent found
526 * in the leaf. It looks the same as the create case, but trans->transid
527 * will be different when the block is cow'd.
528 *
529 * (root_key.objectid, trans->transid, inode objectid, offset in file)
530 *
531 * When a file extent is removed either during snapshot deletion or file
532 * truncation, the corresponding back reference is found
533 * by searching for:
534 *
535 * (btrfs_header_owner(leaf), btrfs_header_generation(leaf),
536 * inode objectid, offset in file)
537 *
538 * Btree extents can be referenced by:
539 *
540 * - Different subvolumes
541 * - Different generations of the same subvolume
542 *
543 * Storing sufficient information for a full reverse mapping of a btree
544 * block would require storing the lowest key of the block in the backref,
545 * and it would require updating that lowest key either before write out or
546 * every time it changed. Instead, the objectid of the lowest key is stored
547 * along with the level of the tree block. This provides a hint
548 * about where in the btree the block can be found. Searches through the
549 * btree only need to look for a pointer to that block, so they stop one
550 * level higher than the level recorded in the backref.
551 *
552 * Some btrees do not do reference counting on their extents. These
553 * include the extent tree and the tree of tree roots. Backrefs for these
554 * trees always have a generation of zero.
555 *
556 * When a tree block is created, back references are inserted:
557 *
558 * (root->root_key.objectid, trans->transid or zero, level, lowest_key_objectid)
559 *
560 * When a tree block is cow'd in a reference counted root,
561 * new back references are added for all the blocks it points to.
562 * These are of the form (trans->transid will have increased since creation):
563 *
564 * (root->root_key.objectid, trans->transid, level, lowest_key_objectid)
565 *
566 * Because the lowest_key_objectid and the level are just hints
567 * they are not used when backrefs are deleted. When a backref is deleted:
568 *
569 * if backref was for a tree root:
570 * root_objectid = root->root_key.objectid
571 * else
572 * root_objectid = btrfs_header_owner(parent)
573 *
574 * (root_objectid, btrfs_header_generation(parent) or zero, 0, 0)
575 *
576 * Back Reference Key hashing:
577 *
578 * Back references have four fields, each 64 bits long. Unfortunately,
579 * This is hashed into a single 64 bit number and placed into the key offset.
580 * The key objectid corresponds to the first byte in the extent, and the
581 * key type is set to BTRFS_EXTENT_REF_KEY
582 */
583 int btrfs_insert_extent_backref(struct btrfs_trans_handle *trans,
584 struct btrfs_root *root,
585 struct btrfs_path *path, u64 bytenr,
586 u64 root_objectid, u64 ref_generation,
587 u64 owner, u64 owner_offset)
588 {
589 u64 hash;
590 struct btrfs_key key;
591 struct btrfs_extent_ref ref;
592 struct btrfs_extent_ref *disk_ref;
593 int ret;
594
595 btrfs_set_stack_ref_root(&ref, root_objectid);
596 btrfs_set_stack_ref_generation(&ref, ref_generation);
597 btrfs_set_stack_ref_objectid(&ref, owner);
598 btrfs_set_stack_ref_offset(&ref, owner_offset);
599
600 hash = hash_extent_ref(root_objectid, ref_generation, owner,
601 owner_offset);
602 key.offset = hash;
603 key.objectid = bytenr;
604 key.type = BTRFS_EXTENT_REF_KEY;
605
606 ret = btrfs_insert_empty_item(trans, root, path, &key, sizeof(ref));
607 while (ret == -EEXIST) {
608 disk_ref = btrfs_item_ptr(path->nodes[0], path->slots[0],
609 struct btrfs_extent_ref);
610 if (match_extent_ref(path->nodes[0], disk_ref, &ref))
611 goto out;
612 key.offset++;
613 btrfs_release_path(root, path);
614 ret = btrfs_insert_empty_item(trans, root, path, &key,
615 sizeof(ref));
616 }
617 if (ret)
618 goto out;
619 disk_ref = btrfs_item_ptr(path->nodes[0], path->slots[0],
620 struct btrfs_extent_ref);
621 write_extent_buffer(path->nodes[0], &ref, (unsigned long)disk_ref,
622 sizeof(ref));
623 btrfs_mark_buffer_dirty(path->nodes[0]);
624 out:
625 btrfs_release_path(root, path);
626 return ret;
627 }
628
629 int btrfs_inc_extent_ref(struct btrfs_trans_handle *trans,
630 struct btrfs_root *root,
631 u64 bytenr, u64 num_bytes,
632 u64 root_objectid, u64 ref_generation,
633 u64 owner, u64 owner_offset)
634 {
635 struct btrfs_path *path;
636 int ret;
637 struct btrfs_key key;
638 struct extent_buffer *l;
639 struct btrfs_extent_item *item;
640 u32 refs;
641
642 WARN_ON(num_bytes < root->sectorsize);
643 path = btrfs_alloc_path();
644 if (!path)
645 return -ENOMEM;
646
647 path->reada = 1;
648 key.objectid = bytenr;
649 btrfs_set_key_type(&key, BTRFS_EXTENT_ITEM_KEY);
650 key.offset = num_bytes;
651 ret = btrfs_search_slot(trans, root->fs_info->extent_root, &key, path,
652 0, 1);
653 if (ret < 0)
654 return ret;
655 if (ret != 0) {
656 BUG();
657 }
658 BUG_ON(ret != 0);
659 l = path->nodes[0];
660 item = btrfs_item_ptr(l, path->slots[0], struct btrfs_extent_item);
661 refs = btrfs_extent_refs(l, item);
662 btrfs_set_extent_refs(l, item, refs + 1);
663 btrfs_mark_buffer_dirty(path->nodes[0]);
664
665 btrfs_release_path(root->fs_info->extent_root, path);
666
667 path->reada = 1;
668 ret = btrfs_insert_extent_backref(trans, root->fs_info->extent_root,
669 path, bytenr, root_objectid,
670 ref_generation, owner, owner_offset);
671 BUG_ON(ret);
672 finish_current_insert(trans, root->fs_info->extent_root);
673 del_pending_extents(trans, root->fs_info->extent_root);
674
675 btrfs_free_path(path);
676 return 0;
677 }
678
679 int btrfs_extent_post_op(struct btrfs_trans_handle *trans,
680 struct btrfs_root *root)
681 {
682 finish_current_insert(trans, root->fs_info->extent_root);
683 del_pending_extents(trans, root->fs_info->extent_root);
684 return 0;
685 }
686
687 static int lookup_extent_ref(struct btrfs_trans_handle *trans,
688 struct btrfs_root *root, u64 bytenr,
689 u64 num_bytes, u32 *refs)
690 {
691 struct btrfs_path *path;
692 int ret;
693 struct btrfs_key key;
694 struct extent_buffer *l;
695 struct btrfs_extent_item *item;
696
697 WARN_ON(num_bytes < root->sectorsize);
698 path = btrfs_alloc_path();
699 path->reada = 1;
700 key.objectid = bytenr;
701 key.offset = num_bytes;
702 btrfs_set_key_type(&key, BTRFS_EXTENT_ITEM_KEY);
703 ret = btrfs_search_slot(trans, root->fs_info->extent_root, &key, path,
704 0, 0);
705 if (ret < 0)
706 goto out;
707 if (ret != 0) {
708 btrfs_print_leaf(root, path->nodes[0]);
709 printk("failed to find block number %Lu\n", bytenr);
710 BUG();
711 }
712 l = path->nodes[0];
713 item = btrfs_item_ptr(l, path->slots[0], struct btrfs_extent_item);
714 *refs = btrfs_extent_refs(l, item);
715 out:
716 btrfs_free_path(path);
717 return 0;
718 }
719
720 u32 btrfs_count_snapshots_in_path(struct btrfs_root *root,
721 struct btrfs_path *count_path,
722 u64 first_extent)
723 {
724 struct btrfs_root *extent_root = root->fs_info->extent_root;
725 struct btrfs_path *path;
726 u64 bytenr;
727 u64 found_objectid;
728 u64 root_objectid = root->root_key.objectid;
729 u32 total_count = 0;
730 u32 cur_count;
731 u32 nritems;
732 int ret;
733 struct btrfs_key key;
734 struct btrfs_key found_key;
735 struct extent_buffer *l;
736 struct btrfs_extent_item *item;
737 struct btrfs_extent_ref *ref_item;
738 int level = -1;
739
740 path = btrfs_alloc_path();
741 again:
742 if (level == -1)
743 bytenr = first_extent;
744 else
745 bytenr = count_path->nodes[level]->start;
746
747 cur_count = 0;
748 key.objectid = bytenr;
749 key.offset = 0;
750
751 btrfs_set_key_type(&key, BTRFS_EXTENT_ITEM_KEY);
752 ret = btrfs_search_slot(NULL, extent_root, &key, path, 0, 0);
753 if (ret < 0)
754 goto out;
755 BUG_ON(ret == 0);
756
757 l = path->nodes[0];
758 btrfs_item_key_to_cpu(l, &found_key, path->slots[0]);
759
760 if (found_key.objectid != bytenr ||
761 found_key.type != BTRFS_EXTENT_ITEM_KEY) {
762 goto out;
763 }
764
765 item = btrfs_item_ptr(l, path->slots[0], struct btrfs_extent_item);
766 while (1) {
767 l = path->nodes[0];
768 nritems = btrfs_header_nritems(l);
769 if (path->slots[0] >= nritems) {
770 ret = btrfs_next_leaf(extent_root, path);
771 if (ret == 0)
772 continue;
773 break;
774 }
775 btrfs_item_key_to_cpu(l, &found_key, path->slots[0]);
776 if (found_key.objectid != bytenr)
777 break;
778
779 if (found_key.type != BTRFS_EXTENT_REF_KEY) {
780 path->slots[0]++;
781 continue;
782 }
783
784 cur_count++;
785 ref_item = btrfs_item_ptr(l, path->slots[0],
786 struct btrfs_extent_ref);
787 found_objectid = btrfs_ref_root(l, ref_item);
788
789 if (found_objectid != root_objectid) {
790 total_count = 2;
791 goto out;
792 }
793 total_count = 1;
794 path->slots[0]++;
795 }
796 if (cur_count == 0) {
797 total_count = 0;
798 goto out;
799 }
800 if (level >= 0 && root->node == count_path->nodes[level])
801 goto out;
802 level++;
803 btrfs_release_path(root, path);
804 goto again;
805
806 out:
807 btrfs_free_path(path);
808 return total_count;
809 }
810 int btrfs_inc_root_ref(struct btrfs_trans_handle *trans,
811 struct btrfs_root *root, u64 owner_objectid)
812 {
813 u64 generation;
814 u64 key_objectid;
815 u64 level;
816 u32 nritems;
817 struct btrfs_disk_key disk_key;
818
819 level = btrfs_header_level(root->node);
820 generation = trans->transid;
821 nritems = btrfs_header_nritems(root->node);
822 if (nritems > 0) {
823 if (level == 0)
824 btrfs_item_key(root->node, &disk_key, 0);
825 else
826 btrfs_node_key(root->node, &disk_key, 0);
827 key_objectid = btrfs_disk_key_objectid(&disk_key);
828 } else {
829 key_objectid = 0;
830 }
831 return btrfs_inc_extent_ref(trans, root, root->node->start,
832 root->node->len, owner_objectid,
833 generation, level, key_objectid);
834 }
835
836 int btrfs_inc_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root,
837 struct extent_buffer *buf)
838 {
839 u64 bytenr;
840 u32 nritems;
841 struct btrfs_key key;
842 struct btrfs_file_extent_item *fi;
843 int i;
844 int level;
845 int ret;
846 int faili;
847
848 if (!root->ref_cows)
849 return 0;
850
851 level = btrfs_header_level(buf);
852 nritems = btrfs_header_nritems(buf);
853 for (i = 0; i < nritems; i++) {
854 if (level == 0) {
855 u64 disk_bytenr;
856 btrfs_item_key_to_cpu(buf, &key, i);
857 if (btrfs_key_type(&key) != BTRFS_EXTENT_DATA_KEY)
858 continue;
859 fi = btrfs_item_ptr(buf, i,
860 struct btrfs_file_extent_item);
861 if (btrfs_file_extent_type(buf, fi) ==
862 BTRFS_FILE_EXTENT_INLINE)
863 continue;
864 disk_bytenr = btrfs_file_extent_disk_bytenr(buf, fi);
865 if (disk_bytenr == 0)
866 continue;
867 ret = btrfs_inc_extent_ref(trans, root, disk_bytenr,
868 btrfs_file_extent_disk_num_bytes(buf, fi),
869 root->root_key.objectid, trans->transid,
870 key.objectid, key.offset);
871 if (ret) {
872 faili = i;
873 goto fail;
874 }
875 } else {
876 bytenr = btrfs_node_blockptr(buf, i);
877 btrfs_node_key_to_cpu(buf, &key, i);
878 ret = btrfs_inc_extent_ref(trans, root, bytenr,
879 btrfs_level_size(root, level - 1),
880 root->root_key.objectid,
881 trans->transid,
882 level - 1, key.objectid);
883 if (ret) {
884 faili = i;
885 goto fail;
886 }
887 }
888 }
889 return 0;
890 fail:
891 WARN_ON(1);
892 #if 0
893 for (i =0; i < faili; i++) {
894 if (level == 0) {
895 u64 disk_bytenr;
896 btrfs_item_key_to_cpu(buf, &key, i);
897 if (btrfs_key_type(&key) != BTRFS_EXTENT_DATA_KEY)
898 continue;
899 fi = btrfs_item_ptr(buf, i,
900 struct btrfs_file_extent_item);
901 if (btrfs_file_extent_type(buf, fi) ==
902 BTRFS_FILE_EXTENT_INLINE)
903 continue;
904 disk_bytenr = btrfs_file_extent_disk_bytenr(buf, fi);
905 if (disk_bytenr == 0)
906 continue;
907 err = btrfs_free_extent(trans, root, disk_bytenr,
908 btrfs_file_extent_disk_num_bytes(buf,
909 fi), 0);
910 BUG_ON(err);
911 } else {
912 bytenr = btrfs_node_blockptr(buf, i);
913 err = btrfs_free_extent(trans, root, bytenr,
914 btrfs_level_size(root, level - 1), 0);
915 BUG_ON(err);
916 }
917 }
918 #endif
919 return ret;
920 }
921
922 static int write_one_cache_group(struct btrfs_trans_handle *trans,
923 struct btrfs_root *root,
924 struct btrfs_path *path,
925 struct btrfs_block_group_cache *cache)
926 {
927 int ret;
928 int pending_ret;
929 struct btrfs_root *extent_root = root->fs_info->extent_root;
930 unsigned long bi;
931 struct extent_buffer *leaf;
932
933 ret = btrfs_search_slot(trans, extent_root, &cache->key, path, 0, 1);
934 if (ret < 0)
935 goto fail;
936 BUG_ON(ret);
937
938 leaf = path->nodes[0];
939 bi = btrfs_item_ptr_offset(leaf, path->slots[0]);
940 write_extent_buffer(leaf, &cache->item, bi, sizeof(cache->item));
941 btrfs_mark_buffer_dirty(leaf);
942 btrfs_release_path(extent_root, path);
943 fail:
944 finish_current_insert(trans, extent_root);
945 pending_ret = del_pending_extents(trans, extent_root);
946 if (ret)
947 return ret;
948 if (pending_ret)
949 return pending_ret;
950 return 0;
951
952 }
953
954 int btrfs_write_dirty_block_groups(struct btrfs_trans_handle *trans,
955 struct btrfs_root *root)
956 {
957 struct extent_io_tree *block_group_cache;
958 struct btrfs_block_group_cache *cache;
959 int ret;
960 int err = 0;
961 int werr = 0;
962 struct btrfs_path *path;
963 u64 last = 0;
964 u64 start;
965 u64 end;
966 u64 ptr;
967
968 block_group_cache = &root->fs_info->block_group_cache;
969 path = btrfs_alloc_path();
970 if (!path)
971 return -ENOMEM;
972
973 while(1) {
974 ret = find_first_extent_bit(block_group_cache, last,
975 &start, &end, BLOCK_GROUP_DIRTY);
976 if (ret)
977 break;
978
979 last = end + 1;
980 ret = get_state_private(block_group_cache, start, &ptr);
981 if (ret)
982 break;
983 cache = (struct btrfs_block_group_cache *)(unsigned long)ptr;
984 err = write_one_cache_group(trans, root,
985 path, cache);
986 /*
987 * if we fail to write the cache group, we want
988 * to keep it marked dirty in hopes that a later
989 * write will work
990 */
991 if (err) {
992 werr = err;
993 continue;
994 }
995 clear_extent_bits(block_group_cache, start, end,
996 BLOCK_GROUP_DIRTY, GFP_NOFS);
997 }
998 btrfs_free_path(path);
999 return werr;
1000 }
1001
1002 static struct btrfs_space_info *__find_space_info(struct btrfs_fs_info *info,
1003 u64 flags)
1004 {
1005 struct list_head *head = &info->space_info;
1006 struct list_head *cur;
1007 struct btrfs_space_info *found;
1008 list_for_each(cur, head) {
1009 found = list_entry(cur, struct btrfs_space_info, list);
1010 if (found->flags == flags)
1011 return found;
1012 }
1013 return NULL;
1014
1015 }
1016
1017 static int update_space_info(struct btrfs_fs_info *info, u64 flags,
1018 u64 total_bytes, u64 bytes_used,
1019 struct btrfs_space_info **space_info)
1020 {
1021 struct btrfs_space_info *found;
1022
1023 found = __find_space_info(info, flags);
1024 if (found) {
1025 found->total_bytes += total_bytes;
1026 found->bytes_used += bytes_used;
1027 found->full = 0;
1028 WARN_ON(found->total_bytes < found->bytes_used);
1029 *space_info = found;
1030 return 0;
1031 }
1032 found = kmalloc(sizeof(*found), GFP_NOFS);
1033 if (!found)
1034 return -ENOMEM;
1035
1036 list_add(&found->list, &info->space_info);
1037 found->flags = flags;
1038 found->total_bytes = total_bytes;
1039 found->bytes_used = bytes_used;
1040 found->bytes_pinned = 0;
1041 found->full = 0;
1042 *space_info = found;
1043 return 0;
1044 }
1045
1046 static void set_avail_alloc_bits(struct btrfs_fs_info *fs_info, u64 flags)
1047 {
1048 u64 extra_flags = flags & (BTRFS_BLOCK_GROUP_RAID0 |
1049 BTRFS_BLOCK_GROUP_RAID1 |
1050 BTRFS_BLOCK_GROUP_RAID10 |
1051 BTRFS_BLOCK_GROUP_DUP);
1052 if (extra_flags) {
1053 if (flags & BTRFS_BLOCK_GROUP_DATA)
1054 fs_info->avail_data_alloc_bits |= extra_flags;
1055 if (flags & BTRFS_BLOCK_GROUP_METADATA)
1056 fs_info->avail_metadata_alloc_bits |= extra_flags;
1057 if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
1058 fs_info->avail_system_alloc_bits |= extra_flags;
1059 }
1060 }
1061
1062 static u64 reduce_alloc_profile(u64 flags)
1063 {
1064 if ((flags & BTRFS_BLOCK_GROUP_DUP) &&
1065 (flags & (BTRFS_BLOCK_GROUP_RAID1 |
1066 BTRFS_BLOCK_GROUP_RAID10)))
1067 flags &= ~BTRFS_BLOCK_GROUP_DUP;
1068
1069 if ((flags & BTRFS_BLOCK_GROUP_RAID1) &&
1070 (flags & BTRFS_BLOCK_GROUP_RAID10))
1071 flags &= ~BTRFS_BLOCK_GROUP_RAID1;
1072
1073 if ((flags & BTRFS_BLOCK_GROUP_RAID0) &&
1074 ((flags & BTRFS_BLOCK_GROUP_RAID1) |
1075 (flags & BTRFS_BLOCK_GROUP_RAID10) |
1076 (flags & BTRFS_BLOCK_GROUP_DUP)))
1077 flags &= ~BTRFS_BLOCK_GROUP_RAID0;
1078 return flags;
1079 }
1080
1081
1082 static int do_chunk_alloc(struct btrfs_trans_handle *trans,
1083 struct btrfs_root *extent_root, u64 alloc_bytes,
1084 u64 flags)
1085 {
1086 struct btrfs_space_info *space_info;
1087 u64 thresh;
1088 u64 start;
1089 u64 num_bytes;
1090 int ret;
1091
1092 flags = reduce_alloc_profile(flags);
1093
1094 space_info = __find_space_info(extent_root->fs_info, flags);
1095 if (!space_info) {
1096 ret = update_space_info(extent_root->fs_info, flags,
1097 0, 0, &space_info);
1098 BUG_ON(ret);
1099 }
1100 BUG_ON(!space_info);
1101
1102 if (space_info->full)
1103 return 0;
1104
1105 thresh = div_factor(space_info->total_bytes, 6);
1106 if ((space_info->bytes_used + space_info->bytes_pinned + alloc_bytes) <
1107 thresh)
1108 return 0;
1109
1110 ret = btrfs_alloc_chunk(trans, extent_root, &start, &num_bytes, flags);
1111 if (ret == -ENOSPC) {
1112 printk("space info full %Lu\n", flags);
1113 space_info->full = 1;
1114 return 0;
1115 }
1116
1117 BUG_ON(ret);
1118
1119 ret = btrfs_make_block_group(trans, extent_root, 0, flags,
1120 BTRFS_FIRST_CHUNK_TREE_OBJECTID, start, num_bytes);
1121 BUG_ON(ret);
1122
1123 return 0;
1124 }
1125
1126 static int update_block_group(struct btrfs_trans_handle *trans,
1127 struct btrfs_root *root,
1128 u64 bytenr, u64 num_bytes, int alloc,
1129 int mark_free)
1130 {
1131 struct btrfs_block_group_cache *cache;
1132 struct btrfs_fs_info *info = root->fs_info;
1133 u64 total = num_bytes;
1134 u64 old_val;
1135 u64 byte_in_group;
1136 u64 start;
1137 u64 end;
1138
1139 while(total) {
1140 cache = btrfs_lookup_block_group(info, bytenr);
1141 if (!cache) {
1142 return -1;
1143 }
1144 byte_in_group = bytenr - cache->key.objectid;
1145 WARN_ON(byte_in_group > cache->key.offset);
1146 start = cache->key.objectid;
1147 end = start + cache->key.offset - 1;
1148 set_extent_bits(&info->block_group_cache, start, end,
1149 BLOCK_GROUP_DIRTY, GFP_NOFS);
1150
1151 old_val = btrfs_block_group_used(&cache->item);
1152 num_bytes = min(total, cache->key.offset - byte_in_group);
1153 if (alloc) {
1154 old_val += num_bytes;
1155 cache->space_info->bytes_used += num_bytes;
1156 } else {
1157 old_val -= num_bytes;
1158 cache->space_info->bytes_used -= num_bytes;
1159 if (mark_free) {
1160 set_extent_dirty(&info->free_space_cache,
1161 bytenr, bytenr + num_bytes - 1,
1162 GFP_NOFS);
1163 }
1164 }
1165 btrfs_set_block_group_used(&cache->item, old_val);
1166 total -= num_bytes;
1167 bytenr += num_bytes;
1168 }
1169 return 0;
1170 }
1171
1172 static int update_pinned_extents(struct btrfs_root *root,
1173 u64 bytenr, u64 num, int pin)
1174 {
1175 u64 len;
1176 struct btrfs_block_group_cache *cache;
1177 struct btrfs_fs_info *fs_info = root->fs_info;
1178
1179 if (pin) {
1180 set_extent_dirty(&fs_info->pinned_extents,
1181 bytenr, bytenr + num - 1, GFP_NOFS);
1182 } else {
1183 clear_extent_dirty(&fs_info->pinned_extents,
1184 bytenr, bytenr + num - 1, GFP_NOFS);
1185 }
1186 while (num > 0) {
1187 cache = btrfs_lookup_block_group(fs_info, bytenr);
1188 WARN_ON(!cache);
1189 len = min(num, cache->key.offset -
1190 (bytenr - cache->key.objectid));
1191 if (pin) {
1192 cache->pinned += len;
1193 cache->space_info->bytes_pinned += len;
1194 fs_info->total_pinned += len;
1195 } else {
1196 cache->pinned -= len;
1197 cache->space_info->bytes_pinned -= len;
1198 fs_info->total_pinned -= len;
1199 }
1200 bytenr += len;
1201 num -= len;
1202 }
1203 return 0;
1204 }
1205
1206 int btrfs_copy_pinned(struct btrfs_root *root, struct extent_io_tree *copy)
1207 {
1208 u64 last = 0;
1209 u64 start;
1210 u64 end;
1211 struct extent_io_tree *pinned_extents = &root->fs_info->pinned_extents;
1212 int ret;
1213
1214 while(1) {
1215 ret = find_first_extent_bit(pinned_extents, last,
1216 &start, &end, EXTENT_DIRTY);
1217 if (ret)
1218 break;
1219 set_extent_dirty(copy, start, end, GFP_NOFS);
1220 last = end + 1;
1221 }
1222 return 0;
1223 }
1224
1225 int btrfs_finish_extent_commit(struct btrfs_trans_handle *trans,
1226 struct btrfs_root *root,
1227 struct extent_io_tree *unpin)
1228 {
1229 u64 start;
1230 u64 end;
1231 int ret;
1232 struct extent_io_tree *free_space_cache;
1233 free_space_cache = &root->fs_info->free_space_cache;
1234
1235 while(1) {
1236 ret = find_first_extent_bit(unpin, 0, &start, &end,
1237 EXTENT_DIRTY);
1238 if (ret)
1239 break;
1240 update_pinned_extents(root, start, end + 1 - start, 0);
1241 clear_extent_dirty(unpin, start, end, GFP_NOFS);
1242 set_extent_dirty(free_space_cache, start, end, GFP_NOFS);
1243 }
1244 return 0;
1245 }
1246
1247 static int finish_current_insert(struct btrfs_trans_handle *trans,
1248 struct btrfs_root *extent_root)
1249 {
1250 u64 start;
1251 u64 end;
1252 struct btrfs_fs_info *info = extent_root->fs_info;
1253 struct extent_buffer *eb;
1254 struct btrfs_path *path;
1255 struct btrfs_key ins;
1256 struct btrfs_disk_key first;
1257 struct btrfs_extent_item extent_item;
1258 int ret;
1259 int level;
1260 int err = 0;
1261
1262 btrfs_set_stack_extent_refs(&extent_item, 1);
1263 btrfs_set_key_type(&ins, BTRFS_EXTENT_ITEM_KEY);
1264 path = btrfs_alloc_path();
1265
1266 while(1) {
1267 ret = find_first_extent_bit(&info->extent_ins, 0, &start,
1268 &end, EXTENT_LOCKED);
1269 if (ret)
1270 break;
1271
1272 ins.objectid = start;
1273 ins.offset = end + 1 - start;
1274 err = btrfs_insert_item(trans, extent_root, &ins,
1275 &extent_item, sizeof(extent_item));
1276 clear_extent_bits(&info->extent_ins, start, end, EXTENT_LOCKED,
1277 GFP_NOFS);
1278 eb = read_tree_block(extent_root, ins.objectid, ins.offset);
1279 level = btrfs_header_level(eb);
1280 if (level == 0) {
1281 btrfs_item_key(eb, &first, 0);
1282 } else {
1283 btrfs_node_key(eb, &first, 0);
1284 }
1285 err = btrfs_insert_extent_backref(trans, extent_root, path,
1286 start, extent_root->root_key.objectid,
1287 0, level,
1288 btrfs_disk_key_objectid(&first));
1289 BUG_ON(err);
1290 free_extent_buffer(eb);
1291 }
1292 btrfs_free_path(path);
1293 return 0;
1294 }
1295
1296 static int pin_down_bytes(struct btrfs_root *root, u64 bytenr, u32 num_bytes,
1297 int pending)
1298 {
1299 int err = 0;
1300 struct extent_buffer *buf;
1301
1302 if (!pending) {
1303 buf = btrfs_find_tree_block(root, bytenr, num_bytes);
1304 if (buf) {
1305 if (btrfs_buffer_uptodate(buf)) {
1306 u64 transid =
1307 root->fs_info->running_transaction->transid;
1308 u64 header_transid =
1309 btrfs_header_generation(buf);
1310 if (header_transid == transid &&
1311 !btrfs_header_flag(buf,
1312 BTRFS_HEADER_FLAG_WRITTEN)) {
1313 clean_tree_block(NULL, root, buf);
1314 free_extent_buffer(buf);
1315 return 1;
1316 }
1317 }
1318 free_extent_buffer(buf);
1319 }
1320 update_pinned_extents(root, bytenr, num_bytes, 1);
1321 } else {
1322 set_extent_bits(&root->fs_info->pending_del,
1323 bytenr, bytenr + num_bytes - 1,
1324 EXTENT_LOCKED, GFP_NOFS);
1325 }
1326 BUG_ON(err < 0);
1327 return 0;
1328 }
1329
1330 /*
1331 * remove an extent from the root, returns 0 on success
1332 */
1333 static int __free_extent(struct btrfs_trans_handle *trans, struct btrfs_root
1334 *root, u64 bytenr, u64 num_bytes,
1335 u64 root_objectid, u64 ref_generation,
1336 u64 owner_objectid, u64 owner_offset, int pin,
1337 int mark_free)
1338 {
1339 struct btrfs_path *path;
1340 struct btrfs_key key;
1341 struct btrfs_fs_info *info = root->fs_info;
1342 struct btrfs_root *extent_root = info->extent_root;
1343 struct extent_buffer *leaf;
1344 int ret;
1345 int extent_slot = 0;
1346 int found_extent = 0;
1347 int num_to_del = 1;
1348 struct btrfs_extent_item *ei;
1349 u32 refs;
1350
1351 key.objectid = bytenr;
1352 btrfs_set_key_type(&key, BTRFS_EXTENT_ITEM_KEY);
1353 key.offset = num_bytes;
1354 path = btrfs_alloc_path();
1355 if (!path)
1356 return -ENOMEM;
1357
1358 path->reada = 1;
1359 ret = lookup_extent_backref(trans, extent_root, path,
1360 bytenr, root_objectid,
1361 ref_generation,
1362 owner_objectid, owner_offset, 1);
1363 if (ret == 0) {
1364 struct btrfs_key found_key;
1365 extent_slot = path->slots[0];
1366 while(extent_slot > 0) {
1367 extent_slot--;
1368 btrfs_item_key_to_cpu(path->nodes[0], &found_key,
1369 extent_slot);
1370 if (found_key.objectid != bytenr)
1371 break;
1372 if (found_key.type == BTRFS_EXTENT_ITEM_KEY &&
1373 found_key.offset == num_bytes) {
1374 found_extent = 1;
1375 break;
1376 }
1377 if (path->slots[0] - extent_slot > 5)
1378 break;
1379 }
1380 if (!found_extent)
1381 ret = btrfs_del_item(trans, extent_root, path);
1382 } else {
1383 btrfs_print_leaf(extent_root, path->nodes[0]);
1384 WARN_ON(1);
1385 printk("Unable to find ref byte nr %Lu root %Lu "
1386 " gen %Lu owner %Lu offset %Lu\n", bytenr,
1387 root_objectid, ref_generation, owner_objectid,
1388 owner_offset);
1389 }
1390 if (!found_extent) {
1391 btrfs_release_path(extent_root, path);
1392 ret = btrfs_search_slot(trans, extent_root, &key, path, -1, 1);
1393 if (ret < 0)
1394 return ret;
1395 BUG_ON(ret);
1396 extent_slot = path->slots[0];
1397 }
1398
1399 leaf = path->nodes[0];
1400 ei = btrfs_item_ptr(leaf, extent_slot,
1401 struct btrfs_extent_item);
1402 refs = btrfs_extent_refs(leaf, ei);
1403 BUG_ON(refs == 0);
1404 refs -= 1;
1405 btrfs_set_extent_refs(leaf, ei, refs);
1406
1407 btrfs_mark_buffer_dirty(leaf);
1408
1409 if (refs == 0 && found_extent && path->slots[0] == extent_slot + 1) {
1410 /* if the back ref and the extent are next to each other
1411 * they get deleted below in one shot
1412 */
1413 path->slots[0] = extent_slot;
1414 num_to_del = 2;
1415 } else if (found_extent) {
1416 /* otherwise delete the extent back ref */
1417 ret = btrfs_del_item(trans, extent_root, path);
1418 BUG_ON(ret);
1419 /* if refs are 0, we need to setup the path for deletion */
1420 if (refs == 0) {
1421 btrfs_release_path(extent_root, path);
1422 ret = btrfs_search_slot(trans, extent_root, &key, path,
1423 -1, 1);
1424 if (ret < 0)
1425 return ret;
1426 BUG_ON(ret);
1427 }
1428 }
1429
1430 if (refs == 0) {
1431 u64 super_used;
1432 u64 root_used;
1433
1434 if (pin) {
1435 ret = pin_down_bytes(root, bytenr, num_bytes, 0);
1436 if (ret > 0)
1437 mark_free = 1;
1438 BUG_ON(ret < 0);
1439 }
1440
1441 /* block accounting for super block */
1442 super_used = btrfs_super_bytes_used(&info->super_copy);
1443 btrfs_set_super_bytes_used(&info->super_copy,
1444 super_used - num_bytes);
1445
1446 /* block accounting for root item */
1447 root_used = btrfs_root_used(&root->root_item);
1448 btrfs_set_root_used(&root->root_item,
1449 root_used - num_bytes);
1450 ret = btrfs_del_items(trans, extent_root, path, path->slots[0],
1451 num_to_del);
1452 if (ret) {
1453 return ret;
1454 }
1455 ret = update_block_group(trans, root, bytenr, num_bytes, 0,
1456 mark_free);
1457 BUG_ON(ret);
1458 }
1459 btrfs_free_path(path);
1460 finish_current_insert(trans, extent_root);
1461 return ret;
1462 }
1463
1464 /*
1465 * find all the blocks marked as pending in the radix tree and remove
1466 * them from the extent map
1467 */
1468 static int del_pending_extents(struct btrfs_trans_handle *trans, struct
1469 btrfs_root *extent_root)
1470 {
1471 int ret;
1472 int err = 0;
1473 u64 start;
1474 u64 end;
1475 struct extent_io_tree *pending_del;
1476 struct extent_io_tree *pinned_extents;
1477
1478 pending_del = &extent_root->fs_info->pending_del;
1479 pinned_extents = &extent_root->fs_info->pinned_extents;
1480
1481 while(1) {
1482 ret = find_first_extent_bit(pending_del, 0, &start, &end,
1483 EXTENT_LOCKED);
1484 if (ret)
1485 break;
1486 update_pinned_extents(extent_root, start, end + 1 - start, 1);
1487 clear_extent_bits(pending_del, start, end, EXTENT_LOCKED,
1488 GFP_NOFS);
1489 ret = __free_extent(trans, extent_root,
1490 start, end + 1 - start,
1491 extent_root->root_key.objectid,
1492 0, 0, 0, 0, 0);
1493 if (ret)
1494 err = ret;
1495 }
1496 return err;
1497 }
1498
1499 /*
1500 * remove an extent from the root, returns 0 on success
1501 */
1502 int btrfs_free_extent(struct btrfs_trans_handle *trans, struct btrfs_root
1503 *root, u64 bytenr, u64 num_bytes,
1504 u64 root_objectid, u64 ref_generation,
1505 u64 owner_objectid, u64 owner_offset, int pin)
1506 {
1507 struct btrfs_root *extent_root = root->fs_info->extent_root;
1508 int pending_ret;
1509 int ret;
1510
1511 WARN_ON(num_bytes < root->sectorsize);
1512 if (!root->ref_cows)
1513 ref_generation = 0;
1514
1515 if (root == extent_root) {
1516 pin_down_bytes(root, bytenr, num_bytes, 1);
1517 return 0;
1518 }
1519 ret = __free_extent(trans, root, bytenr, num_bytes, root_objectid,
1520 ref_generation, owner_objectid, owner_offset,
1521 pin, pin == 0);
1522 pending_ret = del_pending_extents(trans, root->fs_info->extent_root);
1523 return ret ? ret : pending_ret;
1524 }
1525
1526 static u64 stripe_align(struct btrfs_root *root, u64 val)
1527 {
1528 u64 mask = ((u64)root->stripesize - 1);
1529 u64 ret = (val + mask) & ~mask;
1530 return ret;
1531 }
1532
1533 /*
1534 * walks the btree of allocated extents and find a hole of a given size.
1535 * The key ins is changed to record the hole:
1536 * ins->objectid == block start
1537 * ins->flags = BTRFS_EXTENT_ITEM_KEY
1538 * ins->offset == number of blocks
1539 * Any available blocks before search_start are skipped.
1540 */
1541 static int noinline find_free_extent(struct btrfs_trans_handle *trans,
1542 struct btrfs_root *orig_root,
1543 u64 num_bytes, u64 empty_size,
1544 u64 search_start, u64 search_end,
1545 u64 hint_byte, struct btrfs_key *ins,
1546 u64 exclude_start, u64 exclude_nr,
1547 int data)
1548 {
1549 int ret;
1550 u64 orig_search_start = search_start;
1551 struct btrfs_root * root = orig_root->fs_info->extent_root;
1552 struct btrfs_fs_info *info = root->fs_info;
1553 u64 total_needed = num_bytes;
1554 u64 *last_ptr = NULL;
1555 struct btrfs_block_group_cache *block_group;
1556 int full_scan = 0;
1557 int wrapped = 0;
1558 int empty_cluster = 2 * 1024 * 1024;
1559
1560 WARN_ON(num_bytes < root->sectorsize);
1561 btrfs_set_key_type(ins, BTRFS_EXTENT_ITEM_KEY);
1562
1563 if (data & BTRFS_BLOCK_GROUP_METADATA) {
1564 last_ptr = &root->fs_info->last_alloc;
1565 empty_cluster = 256 * 1024;
1566 }
1567
1568 if ((data & BTRFS_BLOCK_GROUP_DATA) && btrfs_test_opt(root, SSD)) {
1569 last_ptr = &root->fs_info->last_data_alloc;
1570 }
1571
1572 if (last_ptr) {
1573 if (*last_ptr)
1574 hint_byte = *last_ptr;
1575 else {
1576 empty_size += empty_cluster;
1577 }
1578 }
1579
1580 if (search_end == (u64)-1)
1581 search_end = btrfs_super_total_bytes(&info->super_copy);
1582
1583 if (hint_byte) {
1584 block_group = btrfs_lookup_block_group(info, hint_byte);
1585 if (!block_group)
1586 hint_byte = search_start;
1587 block_group = btrfs_find_block_group(root, block_group,
1588 hint_byte, data, 1);
1589 if (last_ptr && *last_ptr == 0 && block_group)
1590 hint_byte = block_group->key.objectid;
1591 } else {
1592 block_group = btrfs_find_block_group(root,
1593 trans->block_group,
1594 search_start, data, 1);
1595 }
1596 search_start = max(search_start, hint_byte);
1597
1598 total_needed += empty_size;
1599
1600 check_failed:
1601 if (!block_group) {
1602 block_group = btrfs_lookup_block_group(info, search_start);
1603 if (!block_group)
1604 block_group = btrfs_lookup_block_group(info,
1605 orig_search_start);
1606 }
1607 ret = find_search_start(root, &block_group, &search_start,
1608 total_needed, data);
1609 if (ret == -ENOSPC && last_ptr && *last_ptr) {
1610 *last_ptr = 0;
1611 block_group = btrfs_lookup_block_group(info,
1612 orig_search_start);
1613 search_start = orig_search_start;
1614 ret = find_search_start(root, &block_group, &search_start,
1615 total_needed, data);
1616 }
1617 if (ret == -ENOSPC)
1618 goto enospc;
1619 if (ret)
1620 goto error;
1621
1622 if (last_ptr && *last_ptr && search_start != *last_ptr) {
1623 *last_ptr = 0;
1624 if (!empty_size) {
1625 empty_size += empty_cluster;
1626 total_needed += empty_size;
1627 }
1628 block_group = btrfs_lookup_block_group(info,
1629 orig_search_start);
1630 search_start = orig_search_start;
1631 ret = find_search_start(root, &block_group,
1632 &search_start, total_needed, data);
1633 if (ret == -ENOSPC)
1634 goto enospc;
1635 if (ret)
1636 goto error;
1637 }
1638
1639 search_start = stripe_align(root, search_start);
1640 ins->objectid = search_start;
1641 ins->offset = num_bytes;
1642
1643 if (ins->objectid + num_bytes >= search_end)
1644 goto enospc;
1645
1646 if (ins->objectid + num_bytes >
1647 block_group->key.objectid + block_group->key.offset) {
1648 search_start = block_group->key.objectid +
1649 block_group->key.offset;
1650 goto new_group;
1651 }
1652
1653 if (test_range_bit(&info->extent_ins, ins->objectid,
1654 ins->objectid + num_bytes -1, EXTENT_LOCKED, 0)) {
1655 search_start = ins->objectid + num_bytes;
1656 goto new_group;
1657 }
1658
1659 if (test_range_bit(&info->pinned_extents, ins->objectid,
1660 ins->objectid + num_bytes -1, EXTENT_DIRTY, 0)) {
1661 search_start = ins->objectid + num_bytes;
1662 goto new_group;
1663 }
1664
1665 if (exclude_nr > 0 && (ins->objectid + num_bytes > exclude_start &&
1666 ins->objectid < exclude_start + exclude_nr)) {
1667 search_start = exclude_start + exclude_nr;
1668 goto new_group;
1669 }
1670
1671 if (!(data & BTRFS_BLOCK_GROUP_DATA)) {
1672 block_group = btrfs_lookup_block_group(info, ins->objectid);
1673 if (block_group)
1674 trans->block_group = block_group;
1675 }
1676 ins->offset = num_bytes;
1677 if (last_ptr) {
1678 *last_ptr = ins->objectid + ins->offset;
1679 if (*last_ptr ==
1680 btrfs_super_total_bytes(&root->fs_info->super_copy)) {
1681 *last_ptr = 0;
1682 }
1683 }
1684 return 0;
1685
1686 new_group:
1687 if (search_start + num_bytes >= search_end) {
1688 enospc:
1689 search_start = orig_search_start;
1690 if (full_scan) {
1691 ret = -ENOSPC;
1692 goto error;
1693 }
1694 if (wrapped) {
1695 if (!full_scan)
1696 total_needed -= empty_size;
1697 full_scan = 1;
1698 } else
1699 wrapped = 1;
1700 }
1701 block_group = btrfs_lookup_block_group(info, search_start);
1702 cond_resched();
1703 block_group = btrfs_find_block_group(root, block_group,
1704 search_start, data, 0);
1705 goto check_failed;
1706
1707 error:
1708 return ret;
1709 }
1710
1711 /*
1712 * finds a free extent and does all the dirty work required for allocation
1713 * returns the key for the extent through ins, and a tree buffer for
1714 * the first block of the extent through buf.
1715 *
1716 * returns 0 if everything worked, non-zero otherwise.
1717 */
1718 int btrfs_alloc_extent(struct btrfs_trans_handle *trans,
1719 struct btrfs_root *root,
1720 u64 num_bytes, u64 min_alloc_size,
1721 u64 root_objectid, u64 ref_generation,
1722 u64 owner, u64 owner_offset,
1723 u64 empty_size, u64 hint_byte,
1724 u64 search_end, struct btrfs_key *ins, u64 data)
1725 {
1726 int ret;
1727 int pending_ret;
1728 u64 super_used;
1729 u64 root_used;
1730 u64 search_start = 0;
1731 u64 alloc_profile;
1732 u32 sizes[2];
1733 struct btrfs_fs_info *info = root->fs_info;
1734 struct btrfs_root *extent_root = info->extent_root;
1735 struct btrfs_extent_item *extent_item;
1736 struct btrfs_extent_ref *ref;
1737 struct btrfs_path *path;
1738 struct btrfs_key keys[2];
1739
1740 if (data) {
1741 alloc_profile = info->avail_data_alloc_bits &
1742 info->data_alloc_profile;
1743 data = BTRFS_BLOCK_GROUP_DATA | alloc_profile;
1744 } else if (root == root->fs_info->chunk_root) {
1745 alloc_profile = info->avail_system_alloc_bits &
1746 info->system_alloc_profile;
1747 data = BTRFS_BLOCK_GROUP_SYSTEM | alloc_profile;
1748 } else {
1749 alloc_profile = info->avail_metadata_alloc_bits &
1750 info->metadata_alloc_profile;
1751 data = BTRFS_BLOCK_GROUP_METADATA | alloc_profile;
1752 }
1753 again:
1754 data = reduce_alloc_profile(data);
1755 if (root->ref_cows) {
1756 if (!(data & BTRFS_BLOCK_GROUP_METADATA)) {
1757 ret = do_chunk_alloc(trans, root->fs_info->extent_root,
1758 2 * 1024 * 1024,
1759 BTRFS_BLOCK_GROUP_METADATA |
1760 (info->metadata_alloc_profile &
1761 info->avail_metadata_alloc_bits));
1762 BUG_ON(ret);
1763 }
1764 ret = do_chunk_alloc(trans, root->fs_info->extent_root,
1765 num_bytes + 2 * 1024 * 1024, data);
1766 BUG_ON(ret);
1767 }
1768
1769 WARN_ON(num_bytes < root->sectorsize);
1770 ret = find_free_extent(trans, root, num_bytes, empty_size,
1771 search_start, search_end, hint_byte, ins,
1772 trans->alloc_exclude_start,
1773 trans->alloc_exclude_nr, data);
1774
1775 if (ret == -ENOSPC && num_bytes > min_alloc_size) {
1776 num_bytes = num_bytes >> 1;
1777 num_bytes = max(num_bytes, min_alloc_size);
1778 goto again;
1779 }
1780 if (ret) {
1781 printk("allocation failed flags %Lu\n", data);
1782 }
1783 BUG_ON(ret);
1784 if (ret)
1785 return ret;
1786
1787 /* block accounting for super block */
1788 super_used = btrfs_super_bytes_used(&info->super_copy);
1789 btrfs_set_super_bytes_used(&info->super_copy, super_used + num_bytes);
1790
1791 /* block accounting for root item */
1792 root_used = btrfs_root_used(&root->root_item);
1793 btrfs_set_root_used(&root->root_item, root_used + num_bytes);
1794
1795 clear_extent_dirty(&root->fs_info->free_space_cache,
1796 ins->objectid, ins->objectid + ins->offset - 1,
1797 GFP_NOFS);
1798
1799 if (root == extent_root) {
1800 set_extent_bits(&root->fs_info->extent_ins, ins->objectid,
1801 ins->objectid + ins->offset - 1,
1802 EXTENT_LOCKED, GFP_NOFS);
1803 goto update_block;
1804 }
1805
1806 WARN_ON(trans->alloc_exclude_nr);
1807 trans->alloc_exclude_start = ins->objectid;
1808 trans->alloc_exclude_nr = ins->offset;
1809
1810 memcpy(&keys[0], ins, sizeof(*ins));
1811 keys[1].offset = hash_extent_ref(root_objectid, ref_generation,
1812 owner, owner_offset);
1813 keys[1].objectid = ins->objectid;
1814 keys[1].type = BTRFS_EXTENT_REF_KEY;
1815 sizes[0] = sizeof(*extent_item);
1816 sizes[1] = sizeof(*ref);
1817
1818 path = btrfs_alloc_path();
1819 BUG_ON(!path);
1820
1821 ret = btrfs_insert_empty_items(trans, extent_root, path, keys,
1822 sizes, 2);
1823
1824 BUG_ON(ret);
1825 extent_item = btrfs_item_ptr(path->nodes[0], path->slots[0],
1826 struct btrfs_extent_item);
1827 btrfs_set_extent_refs(path->nodes[0], extent_item, 1);
1828 ref = btrfs_item_ptr(path->nodes[0], path->slots[0] + 1,
1829 struct btrfs_extent_ref);
1830
1831 btrfs_set_ref_root(path->nodes[0], ref, root_objectid);
1832 btrfs_set_ref_generation(path->nodes[0], ref, ref_generation);
1833 btrfs_set_ref_objectid(path->nodes[0], ref, owner);
1834 btrfs_set_ref_offset(path->nodes[0], ref, owner_offset);
1835
1836 btrfs_mark_buffer_dirty(path->nodes[0]);
1837
1838 trans->alloc_exclude_start = 0;
1839 trans->alloc_exclude_nr = 0;
1840 btrfs_free_path(path);
1841 finish_current_insert(trans, extent_root);
1842 pending_ret = del_pending_extents(trans, extent_root);
1843
1844 if (ret) {
1845 return ret;
1846 }
1847 if (pending_ret) {
1848 return pending_ret;
1849 }
1850
1851 update_block:
1852 ret = update_block_group(trans, root, ins->objectid, ins->offset, 1, 0);
1853 if (ret) {
1854 printk("update block group failed for %Lu %Lu\n",
1855 ins->objectid, ins->offset);
1856 BUG();
1857 }
1858 return 0;
1859 }
1860
1861 /*
1862 * helper function to allocate a block for a given tree
1863 * returns the tree buffer or NULL.
1864 */
1865 struct extent_buffer *btrfs_alloc_free_block(struct btrfs_trans_handle *trans,
1866 struct btrfs_root *root,
1867 u32 blocksize,
1868 u64 root_objectid, u64 hint,
1869 u64 empty_size)
1870 {
1871 u64 ref_generation;
1872
1873 if (root->ref_cows)
1874 ref_generation = trans->transid;
1875 else
1876 ref_generation = 0;
1877
1878
1879 return __btrfs_alloc_free_block(trans, root, blocksize, root_objectid,
1880 ref_generation, 0, 0, hint, empty_size);
1881 }
1882
1883 /*
1884 * helper function to allocate a block for a given tree
1885 * returns the tree buffer or NULL.
1886 */
1887 struct extent_buffer *__btrfs_alloc_free_block(struct btrfs_trans_handle *trans,
1888 struct btrfs_root *root,
1889 u32 blocksize,
1890 u64 root_objectid,
1891 u64 ref_generation,
1892 u64 first_objectid,
1893 int level,
1894 u64 hint,
1895 u64 empty_size)
1896 {
1897 struct btrfs_key ins;
1898 int ret;
1899 struct extent_buffer *buf;
1900
1901 ret = btrfs_alloc_extent(trans, root, blocksize, blocksize,
1902 root_objectid, ref_generation,
1903 level, first_objectid, empty_size, hint,
1904 (u64)-1, &ins, 0);
1905 if (ret) {
1906 BUG_ON(ret > 0);
1907 return ERR_PTR(ret);
1908 }
1909 buf = btrfs_find_create_tree_block(root, ins.objectid, blocksize);
1910 if (!buf) {
1911 btrfs_free_extent(trans, root, ins.objectid, blocksize,
1912 root->root_key.objectid, ref_generation,
1913 0, 0, 0);
1914 return ERR_PTR(-ENOMEM);
1915 }
1916 btrfs_set_header_generation(buf, trans->transid);
1917 clean_tree_block(trans, root, buf);
1918 btrfs_set_buffer_uptodate(buf);
1919
1920 if (PageDirty(buf->first_page)) {
1921 printk("page %lu dirty\n", buf->first_page->index);
1922 WARN_ON(1);
1923 }
1924
1925 set_extent_dirty(&trans->transaction->dirty_pages, buf->start,
1926 buf->start + buf->len - 1, GFP_NOFS);
1927 if (!btrfs_test_opt(root, SSD))
1928 btrfs_set_buffer_defrag(buf);
1929 trans->blocks_used++;
1930 return buf;
1931 }
1932
1933 static int noinline drop_leaf_ref(struct btrfs_trans_handle *trans,
1934 struct btrfs_root *root,
1935 struct extent_buffer *leaf)
1936 {
1937 u64 leaf_owner;
1938 u64 leaf_generation;
1939 struct btrfs_key key;
1940 struct btrfs_file_extent_item *fi;
1941 int i;
1942 int nritems;
1943 int ret;
1944
1945 BUG_ON(!btrfs_is_leaf(leaf));
1946 nritems = btrfs_header_nritems(leaf);
1947 leaf_owner = btrfs_header_owner(leaf);
1948 leaf_generation = btrfs_header_generation(leaf);
1949
1950 for (i = 0; i < nritems; i++) {
1951 u64 disk_bytenr;
1952
1953 btrfs_item_key_to_cpu(leaf, &key, i);
1954 if (btrfs_key_type(&key) != BTRFS_EXTENT_DATA_KEY)
1955 continue;
1956 fi = btrfs_item_ptr(leaf, i, struct btrfs_file_extent_item);
1957 if (btrfs_file_extent_type(leaf, fi) ==
1958 BTRFS_FILE_EXTENT_INLINE)
1959 continue;
1960 /*
1961 * FIXME make sure to insert a trans record that
1962 * repeats the snapshot del on crash
1963 */
1964 disk_bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
1965 if (disk_bytenr == 0)
1966 continue;
1967 ret = btrfs_free_extent(trans, root, disk_bytenr,
1968 btrfs_file_extent_disk_num_bytes(leaf, fi),
1969 leaf_owner, leaf_generation,
1970 key.objectid, key.offset, 0);
1971 BUG_ON(ret);
1972 }
1973 return 0;
1974 }
1975
1976 static void noinline reada_walk_down(struct btrfs_root *root,
1977 struct extent_buffer *node,
1978 int slot)
1979 {
1980 u64 bytenr;
1981 u64 last = 0;
1982 u32 nritems;
1983 u32 refs;
1984 u32 blocksize;
1985 int ret;
1986 int i;
1987 int level;
1988 int skipped = 0;
1989
1990 nritems = btrfs_header_nritems(node);
1991 level = btrfs_header_level(node);
1992 if (level)
1993 return;
1994
1995 for (i = slot; i < nritems && skipped < 32; i++) {
1996 bytenr = btrfs_node_blockptr(node, i);
1997 if (last && ((bytenr > last && bytenr - last > 32 * 1024) ||
1998 (last > bytenr && last - bytenr > 32 * 1024))) {
1999 skipped++;
2000 continue;
2001 }
2002 blocksize = btrfs_level_size(root, level - 1);
2003 if (i != slot) {
2004 ret = lookup_extent_ref(NULL, root, bytenr,
2005 blocksize, &refs);
2006 BUG_ON(ret);
2007 if (refs != 1) {
2008 skipped++;
2009 continue;
2010 }
2011 }
2012 mutex_unlock(&root->fs_info->fs_mutex);
2013 ret = readahead_tree_block(root, bytenr, blocksize);
2014 last = bytenr + blocksize;
2015 cond_resched();
2016 mutex_lock(&root->fs_info->fs_mutex);
2017 if (ret)
2018 break;
2019 }
2020 }
2021
2022 /*
2023 * helper function for drop_snapshot, this walks down the tree dropping ref
2024 * counts as it goes.
2025 */
2026 static int noinline walk_down_tree(struct btrfs_trans_handle *trans,
2027 struct btrfs_root *root,
2028 struct btrfs_path *path, int *level)
2029 {
2030 u64 root_owner;
2031 u64 root_gen;
2032 u64 bytenr;
2033 struct extent_buffer *next;
2034 struct extent_buffer *cur;
2035 struct extent_buffer *parent;
2036 u32 blocksize;
2037 int ret;
2038 u32 refs;
2039
2040 WARN_ON(*level < 0);
2041 WARN_ON(*level >= BTRFS_MAX_LEVEL);
2042 ret = lookup_extent_ref(trans, root,
2043 path->nodes[*level]->start,
2044 path->nodes[*level]->len, &refs);
2045 BUG_ON(ret);
2046 if (refs > 1)
2047 goto out;
2048
2049 /*
2050 * walk down to the last node level and free all the leaves
2051 */
2052 while(*level >= 0) {
2053 WARN_ON(*level < 0);
2054 WARN_ON(*level >= BTRFS_MAX_LEVEL);
2055 cur = path->nodes[*level];
2056
2057 if (btrfs_header_level(cur) != *level)
2058 WARN_ON(1);
2059
2060 if (path->slots[*level] >=
2061 btrfs_header_nritems(cur))
2062 break;
2063 if (*level == 0) {
2064 ret = drop_leaf_ref(trans, root, cur);
2065 BUG_ON(ret);
2066 break;
2067 }
2068 bytenr = btrfs_node_blockptr(cur, path->slots[*level]);
2069 blocksize = btrfs_level_size(root, *level - 1);
2070 ret = lookup_extent_ref(trans, root, bytenr, blocksize, &refs);
2071 BUG_ON(ret);
2072 if (refs != 1) {
2073 parent = path->nodes[*level];
2074 root_owner = btrfs_header_owner(parent);
2075 root_gen = btrfs_header_generation(parent);
2076 path->slots[*level]++;
2077 ret = btrfs_free_extent(trans, root, bytenr,
2078 blocksize, root_owner,
2079 root_gen, 0, 0, 1);
2080 BUG_ON(ret);
2081 continue;
2082 }
2083 next = btrfs_find_tree_block(root, bytenr, blocksize);
2084 if (!next || !btrfs_buffer_uptodate(next)) {
2085 free_extent_buffer(next);
2086 reada_walk_down(root, cur, path->slots[*level]);
2087
2088 mutex_unlock(&root->fs_info->fs_mutex);
2089 next = read_tree_block(root, bytenr, blocksize);
2090 mutex_lock(&root->fs_info->fs_mutex);
2091
2092 /* we've dropped the lock, double check */
2093 ret = lookup_extent_ref(trans, root, bytenr,
2094 blocksize, &refs);
2095 BUG_ON(ret);
2096 if (refs != 1) {
2097 parent = path->nodes[*level];
2098 root_owner = btrfs_header_owner(parent);
2099 root_gen = btrfs_header_generation(parent);
2100
2101 path->slots[*level]++;
2102 free_extent_buffer(next);
2103 ret = btrfs_free_extent(trans, root, bytenr,
2104 blocksize,
2105 root_owner,
2106 root_gen, 0, 0, 1);
2107 BUG_ON(ret);
2108 continue;
2109 }
2110 } else if (next) {
2111 btrfs_verify_block_csum(root, next);
2112 }
2113 WARN_ON(*level <= 0);
2114 if (path->nodes[*level-1])
2115 free_extent_buffer(path->nodes[*level-1]);
2116 path->nodes[*level-1] = next;
2117 *level = btrfs_header_level(next);
2118 path->slots[*level] = 0;
2119 }
2120 out:
2121 WARN_ON(*level < 0);
2122 WARN_ON(*level >= BTRFS_MAX_LEVEL);
2123
2124 if (path->nodes[*level] == root->node) {
2125 root_owner = root->root_key.objectid;
2126 parent = path->nodes[*level];
2127 } else {
2128 parent = path->nodes[*level + 1];
2129 root_owner = btrfs_header_owner(parent);
2130 }
2131
2132 root_gen = btrfs_header_generation(parent);
2133 ret = btrfs_free_extent(trans, root, path->nodes[*level]->start,
2134 path->nodes[*level]->len,
2135 root_owner, root_gen, 0, 0, 1);
2136 free_extent_buffer(path->nodes[*level]);
2137 path->nodes[*level] = NULL;
2138 *level += 1;
2139 BUG_ON(ret);
2140 return 0;
2141 }
2142
2143 /*
2144 * helper for dropping snapshots. This walks back up the tree in the path
2145 * to find the first node higher up where we haven't yet gone through
2146 * all the slots
2147 */
2148 static int noinline walk_up_tree(struct btrfs_trans_handle *trans,
2149 struct btrfs_root *root,
2150 struct btrfs_path *path, int *level)
2151 {
2152 u64 root_owner;
2153 u64 root_gen;
2154 struct btrfs_root_item *root_item = &root->root_item;
2155 int i;
2156 int slot;
2157 int ret;
2158
2159 for(i = *level; i < BTRFS_MAX_LEVEL - 1 && path->nodes[i]; i++) {
2160 slot = path->slots[i];
2161 if (slot < btrfs_header_nritems(path->nodes[i]) - 1) {
2162 struct extent_buffer *node;
2163 struct btrfs_disk_key disk_key;
2164 node = path->nodes[i];
2165 path->slots[i]++;
2166 *level = i;
2167 WARN_ON(*level == 0);
2168 btrfs_node_key(node, &disk_key, path->slots[i]);
2169 memcpy(&root_item->drop_progress,
2170 &disk_key, sizeof(disk_key));
2171 root_item->drop_level = i;
2172 return 0;
2173 } else {
2174 if (path->nodes[*level] == root->node) {
2175 root_owner = root->root_key.objectid;
2176 root_gen =
2177 btrfs_header_generation(path->nodes[*level]);
2178 } else {
2179 struct extent_buffer *node;
2180 node = path->nodes[*level + 1];
2181 root_owner = btrfs_header_owner(node);
2182 root_gen = btrfs_header_generation(node);
2183 }
2184 ret = btrfs_free_extent(trans, root,
2185 path->nodes[*level]->start,
2186 path->nodes[*level]->len,
2187 root_owner, root_gen, 0, 0, 1);
2188 BUG_ON(ret);
2189 free_extent_buffer(path->nodes[*level]);
2190 path->nodes[*level] = NULL;
2191 *level = i + 1;
2192 }
2193 }
2194 return 1;
2195 }
2196
2197 /*
2198 * drop the reference count on the tree rooted at 'snap'. This traverses
2199 * the tree freeing any blocks that have a ref count of zero after being
2200 * decremented.
2201 */
2202 int btrfs_drop_snapshot(struct btrfs_trans_handle *trans, struct btrfs_root
2203 *root)
2204 {
2205 int ret = 0;
2206 int wret;
2207 int level;
2208 struct btrfs_path *path;
2209 int i;
2210 int orig_level;
2211 struct btrfs_root_item *root_item = &root->root_item;
2212
2213 path = btrfs_alloc_path();
2214 BUG_ON(!path);
2215
2216 level = btrfs_header_level(root->node);
2217 orig_level = level;
2218 if (btrfs_disk_key_objectid(&root_item->drop_progress) == 0) {
2219 path->nodes[level] = root->node;
2220 extent_buffer_get(root->node);
2221 path->slots[level] = 0;
2222 } else {
2223 struct btrfs_key key;
2224 struct btrfs_disk_key found_key;
2225 struct extent_buffer *node;
2226
2227 btrfs_disk_key_to_cpu(&key, &root_item->drop_progress);
2228 level = root_item->drop_level;
2229 path->lowest_level = level;
2230 wret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
2231 if (wret < 0) {
2232 ret = wret;
2233 goto out;
2234 }
2235 node = path->nodes[level];
2236 btrfs_node_key(node, &found_key, path->slots[level]);
2237 WARN_ON(memcmp(&found_key, &root_item->drop_progress,
2238 sizeof(found_key)));
2239 }
2240 while(1) {
2241 wret = walk_down_tree(trans, root, path, &level);
2242 if (wret > 0)
2243 break;
2244 if (wret < 0)
2245 ret = wret;
2246
2247 wret = walk_up_tree(trans, root, path, &level);
2248 if (wret > 0)
2249 break;
2250 if (wret < 0)
2251 ret = wret;
2252 ret = -EAGAIN;
2253 break;
2254 }
2255 for (i = 0; i <= orig_level; i++) {
2256 if (path->nodes[i]) {
2257 free_extent_buffer(path->nodes[i]);
2258 path->nodes[i] = NULL;
2259 }
2260 }
2261 out:
2262 btrfs_free_path(path);
2263 return ret;
2264 }
2265
2266 int btrfs_free_block_groups(struct btrfs_fs_info *info)
2267 {
2268 u64 start;
2269 u64 end;
2270 u64 ptr;
2271 int ret;
2272 while(1) {
2273 ret = find_first_extent_bit(&info->block_group_cache, 0,
2274 &start, &end, (unsigned int)-1);
2275 if (ret)
2276 break;
2277 ret = get_state_private(&info->block_group_cache, start, &ptr);
2278 if (!ret)
2279 kfree((void *)(unsigned long)ptr);
2280 clear_extent_bits(&info->block_group_cache, start,
2281 end, (unsigned int)-1, GFP_NOFS);
2282 }
2283 while(1) {
2284 ret = find_first_extent_bit(&info->free_space_cache, 0,
2285 &start, &end, EXTENT_DIRTY);
2286 if (ret)
2287 break;
2288 clear_extent_dirty(&info->free_space_cache, start,
2289 end, GFP_NOFS);
2290 }
2291 return 0;
2292 }
2293
2294 static unsigned long calc_ra(unsigned long start, unsigned long last,
2295 unsigned long nr)
2296 {
2297 return min(last, start + nr - 1);
2298 }
2299
2300 static int noinline relocate_inode_pages(struct inode *inode, u64 start,
2301 u64 len)
2302 {
2303 u64 page_start;
2304 u64 page_end;
2305 unsigned long last_index;
2306 unsigned long i;
2307 struct page *page;
2308 struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
2309 struct file_ra_state *ra;
2310 unsigned long total_read = 0;
2311 unsigned long ra_pages;
2312
2313 ra = kzalloc(sizeof(*ra), GFP_NOFS);
2314
2315 mutex_lock(&inode->i_mutex);
2316 i = start >> PAGE_CACHE_SHIFT;
2317 last_index = (start + len - 1) >> PAGE_CACHE_SHIFT;
2318
2319 ra_pages = BTRFS_I(inode)->root->fs_info->bdi.ra_pages;
2320
2321 file_ra_state_init(ra, inode->i_mapping);
2322
2323 for (; i <= last_index; i++) {
2324 if (total_read % ra_pages == 0) {
2325 btrfs_force_ra(inode->i_mapping, ra, NULL, i,
2326 calc_ra(i, last_index, ra_pages));
2327 }
2328 total_read++;
2329 page = grab_cache_page(inode->i_mapping, i);
2330 if (!page)
2331 goto out_unlock;
2332 if (!PageUptodate(page)) {
2333 btrfs_readpage(NULL, page);
2334 lock_page(page);
2335 if (!PageUptodate(page)) {
2336 unlock_page(page);
2337 page_cache_release(page);
2338 goto out_unlock;
2339 }
2340 }
2341 #if LINUX_VERSION_CODE <= KERNEL_VERSION(2,6,18)
2342 ClearPageDirty(page);
2343 #else
2344 cancel_dirty_page(page, PAGE_CACHE_SIZE);
2345 #endif
2346 wait_on_page_writeback(page);
2347 set_page_extent_mapped(page);
2348 page_start = (u64)page->index << PAGE_CACHE_SHIFT;
2349 page_end = page_start + PAGE_CACHE_SIZE - 1;
2350
2351 lock_extent(io_tree, page_start, page_end, GFP_NOFS);
2352
2353 set_page_dirty(page);
2354 set_extent_delalloc(io_tree, page_start,
2355 page_end, GFP_NOFS);
2356
2357 unlock_extent(io_tree, page_start, page_end, GFP_NOFS);
2358 unlock_page(page);
2359 page_cache_release(page);
2360 balance_dirty_pages_ratelimited_nr(inode->i_mapping, 1);
2361 }
2362
2363 out_unlock:
2364 kfree(ra);
2365 mutex_unlock(&inode->i_mutex);
2366 return 0;
2367 }
2368
2369 /*
2370 * note, this releases the path
2371 */
2372 static int noinline relocate_one_reference(struct btrfs_root *extent_root,
2373 struct btrfs_path *path,
2374 struct btrfs_key *extent_key)
2375 {
2376 struct inode *inode;
2377 struct btrfs_root *found_root;
2378 struct btrfs_key *root_location;
2379 struct btrfs_extent_ref *ref;
2380 u64 ref_root;
2381 u64 ref_gen;
2382 u64 ref_objectid;
2383 u64 ref_offset;
2384 int ret;
2385
2386 ref = btrfs_item_ptr(path->nodes[0], path->slots[0],
2387 struct btrfs_extent_ref);
2388 ref_root = btrfs_ref_root(path->nodes[0], ref);
2389 ref_gen = btrfs_ref_generation(path->nodes[0], ref);
2390 ref_objectid = btrfs_ref_objectid(path->nodes[0], ref);
2391 ref_offset = btrfs_ref_offset(path->nodes[0], ref);
2392 btrfs_release_path(extent_root, path);
2393
2394 root_location = kmalloc(sizeof(*root_location), GFP_NOFS);
2395 root_location->objectid = ref_root;
2396 if (ref_gen == 0)
2397 root_location->offset = 0;
2398 else
2399 root_location->offset = (u64)-1;
2400 root_location->type = BTRFS_ROOT_ITEM_KEY;
2401
2402 found_root = btrfs_read_fs_root_no_name(extent_root->fs_info,
2403 root_location);
2404 BUG_ON(!found_root);
2405 kfree(root_location);
2406
2407 if (ref_objectid >= BTRFS_FIRST_FREE_OBJECTID) {
2408 mutex_unlock(&extent_root->fs_info->fs_mutex);
2409 inode = btrfs_iget_locked(extent_root->fs_info->sb,
2410 ref_objectid, found_root);
2411 if (inode->i_state & I_NEW) {
2412 /* the inode and parent dir are two different roots */
2413 BTRFS_I(inode)->root = found_root;
2414 BTRFS_I(inode)->location.objectid = ref_objectid;
2415 BTRFS_I(inode)->location.type = BTRFS_INODE_ITEM_KEY;
2416 BTRFS_I(inode)->location.offset = 0;
2417 btrfs_read_locked_inode(inode);
2418 unlock_new_inode(inode);
2419
2420 }
2421 /* this can happen if the reference is not against
2422 * the latest version of the tree root
2423 */
2424 if (is_bad_inode(inode)) {
2425 mutex_lock(&extent_root->fs_info->fs_mutex);
2426 goto out;
2427 }
2428 relocate_inode_pages(inode, ref_offset, extent_key->offset);
2429 iput(inode);
2430 mutex_lock(&extent_root->fs_info->fs_mutex);
2431 } else {
2432 struct btrfs_trans_handle *trans;
2433 struct btrfs_key found_key;
2434 struct extent_buffer *eb;
2435 int level;
2436 int i;
2437
2438 trans = btrfs_start_transaction(found_root, 1);
2439 eb = read_tree_block(found_root, extent_key->objectid,
2440 extent_key->offset);
2441 level = btrfs_header_level(eb);
2442
2443 if (level == 0)
2444 btrfs_item_key_to_cpu(eb, &found_key, 0);
2445 else
2446 btrfs_node_key_to_cpu(eb, &found_key, 0);
2447
2448 free_extent_buffer(eb);
2449
2450 path->lowest_level = level;
2451 path->reada = 2;
2452 ret = btrfs_search_slot(trans, found_root, &found_key, path,
2453 0, 1);
2454 path->lowest_level = 0;
2455 for (i = level; i < BTRFS_MAX_LEVEL; i++) {
2456 if (!path->nodes[i])
2457 break;
2458 free_extent_buffer(path->nodes[i]);
2459 path->nodes[i] = NULL;
2460 }
2461 btrfs_release_path(found_root, path);
2462 btrfs_end_transaction(trans, found_root);
2463 }
2464
2465 out:
2466 return 0;
2467 }
2468
2469 static int noinline relocate_one_extent(struct btrfs_root *extent_root,
2470 struct btrfs_path *path,
2471 struct btrfs_key *extent_key)
2472 {
2473 struct btrfs_key key;
2474 struct btrfs_key found_key;
2475 struct extent_buffer *leaf;
2476 u32 nritems;
2477 u32 item_size;
2478 int ret = 0;
2479
2480 key.objectid = extent_key->objectid;
2481 key.type = BTRFS_EXTENT_REF_KEY;
2482 key.offset = 0;
2483
2484 while(1) {
2485 ret = btrfs_search_slot(NULL, extent_root, &key, path, 0, 0);
2486
2487 if (ret < 0)
2488 goto out;
2489
2490 ret = 0;
2491 leaf = path->nodes[0];
2492 nritems = btrfs_header_nritems(leaf);
2493 if (path->slots[0] == nritems)
2494 goto out;
2495
2496 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
2497 if (found_key.objectid != extent_key->objectid)
2498 break;
2499
2500 if (found_key.type != BTRFS_EXTENT_REF_KEY)
2501 break;
2502
2503 key.offset = found_key.offset + 1;
2504 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
2505
2506 ret = relocate_one_reference(extent_root, path, extent_key);
2507 if (ret)
2508 goto out;
2509 }
2510 ret = 0;
2511 out:
2512 btrfs_release_path(extent_root, path);
2513 return ret;
2514 }
2515
2516 static u64 update_block_group_flags(struct btrfs_root *root, u64 flags)
2517 {
2518 u64 num_devices;
2519 u64 stripped = BTRFS_BLOCK_GROUP_RAID0 |
2520 BTRFS_BLOCK_GROUP_RAID1 | BTRFS_BLOCK_GROUP_RAID10;
2521
2522 num_devices = btrfs_super_num_devices(&root->fs_info->super_copy);
2523 if (num_devices == 1) {
2524 stripped |= BTRFS_BLOCK_GROUP_DUP;
2525 stripped = flags & ~stripped;
2526
2527 /* turn raid0 into single device chunks */
2528 if (flags & BTRFS_BLOCK_GROUP_RAID0)
2529 return stripped;
2530
2531 /* turn mirroring into duplication */
2532 if (flags & (BTRFS_BLOCK_GROUP_RAID1 |
2533 BTRFS_BLOCK_GROUP_RAID10))
2534 return stripped | BTRFS_BLOCK_GROUP_DUP;
2535 return flags;
2536 } else {
2537 /* they already had raid on here, just return */
2538 if ((flags & BTRFS_BLOCK_GROUP_DUP) &&
2539 (flags & BTRFS_BLOCK_GROUP_RAID1)) {
2540 }
2541 if (flags & stripped)
2542 return flags;
2543
2544 stripped |= BTRFS_BLOCK_GROUP_DUP;
2545 stripped = flags & ~stripped;
2546
2547 /* switch duplicated blocks with raid1 */
2548 if (flags & BTRFS_BLOCK_GROUP_DUP)
2549 return stripped | BTRFS_BLOCK_GROUP_RAID1;
2550
2551 /* turn single device chunks into raid0 */
2552 return stripped | BTRFS_BLOCK_GROUP_RAID0;
2553 }
2554 return flags;
2555 }
2556
2557 int btrfs_shrink_extent_tree(struct btrfs_root *root, u64 shrink_start)
2558 {
2559 struct btrfs_trans_handle *trans;
2560 struct btrfs_root *tree_root = root->fs_info->tree_root;
2561 struct btrfs_path *path;
2562 u64 cur_byte;
2563 u64 total_found;
2564 u64 shrink_last_byte;
2565 u64 new_alloc_flags;
2566 struct btrfs_block_group_cache *shrink_block_group;
2567 struct btrfs_fs_info *info = root->fs_info;
2568 struct btrfs_key key;
2569 struct btrfs_key found_key;
2570 struct extent_buffer *leaf;
2571 u32 nritems;
2572 int ret;
2573 int progress = 0;
2574
2575 shrink_block_group = btrfs_lookup_block_group(root->fs_info,
2576 shrink_start);
2577 BUG_ON(!shrink_block_group);
2578
2579 shrink_last_byte = shrink_start + shrink_block_group->key.offset;
2580
2581 shrink_block_group->space_info->total_bytes -=
2582 shrink_block_group->key.offset;
2583 path = btrfs_alloc_path();
2584 root = root->fs_info->extent_root;
2585 path->reada = 2;
2586
2587 again:
2588 if (btrfs_block_group_used(&shrink_block_group->item) > 0) {
2589 trans = btrfs_start_transaction(root, 1);
2590 new_alloc_flags = update_block_group_flags(root,
2591 shrink_block_group->flags);
2592 do_chunk_alloc(trans, root->fs_info->extent_root,
2593 btrfs_block_group_used(&shrink_block_group->item) +
2594 2 * 1024 * 1024, new_alloc_flags);
2595 btrfs_end_transaction(trans, root);
2596 }
2597 shrink_block_group->ro = 1;
2598
2599 total_found = 0;
2600 key.objectid = shrink_start;
2601 key.offset = 0;
2602 key.type = 0;
2603 cur_byte = key.objectid;
2604
2605 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
2606 if (ret < 0)
2607 goto out;
2608
2609 ret = btrfs_previous_item(root, path, 0, BTRFS_EXTENT_ITEM_KEY);
2610 if (ret < 0)
2611 goto out;
2612
2613 if (ret == 0) {
2614 leaf = path->nodes[0];
2615 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
2616 if (found_key.objectid + found_key.offset > shrink_start &&
2617 found_key.objectid < shrink_last_byte) {
2618 cur_byte = found_key.objectid;
2619 key.objectid = cur_byte;
2620 }
2621 }
2622 btrfs_release_path(root, path);
2623
2624 while(1) {
2625 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
2626 if (ret < 0)
2627 goto out;
2628
2629 leaf = path->nodes[0];
2630 nritems = btrfs_header_nritems(leaf);
2631 next:
2632 if (path->slots[0] >= nritems) {
2633 ret = btrfs_next_leaf(root, path);
2634 if (ret < 0)
2635 goto out;
2636 if (ret == 1) {
2637 ret = 0;
2638 break;
2639 }
2640 leaf = path->nodes[0];
2641 nritems = btrfs_header_nritems(leaf);
2642 }
2643
2644 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
2645
2646 if (found_key.objectid >= shrink_last_byte)
2647 break;
2648
2649 if (progress && need_resched()) {
2650 memcpy(&key, &found_key, sizeof(key));
2651 mutex_unlock(&root->fs_info->fs_mutex);
2652 cond_resched();
2653 mutex_lock(&root->fs_info->fs_mutex);
2654 btrfs_release_path(root, path);
2655 btrfs_search_slot(NULL, root, &key, path, 0, 0);
2656 progress = 0;
2657 goto next;
2658 }
2659 progress = 1;
2660
2661 if (btrfs_key_type(&found_key) != BTRFS_EXTENT_ITEM_KEY ||
2662 found_key.objectid + found_key.offset <= cur_byte) {
2663 path->slots[0]++;
2664 goto next;
2665 }
2666
2667 total_found++;
2668 cur_byte = found_key.objectid + found_key.offset;
2669 key.objectid = cur_byte;
2670 btrfs_release_path(root, path);
2671 ret = relocate_one_extent(root, path, &found_key);
2672 }
2673
2674 btrfs_release_path(root, path);
2675
2676 if (total_found > 0) {
2677 trans = btrfs_start_transaction(tree_root, 1);
2678 btrfs_commit_transaction(trans, tree_root);
2679
2680 mutex_unlock(&root->fs_info->fs_mutex);
2681 btrfs_clean_old_snapshots(tree_root);
2682 mutex_lock(&root->fs_info->fs_mutex);
2683
2684 trans = btrfs_start_transaction(tree_root, 1);
2685 btrfs_commit_transaction(trans, tree_root);
2686 goto again;
2687 }
2688
2689 /*
2690 * we've freed all the extents, now remove the block
2691 * group item from the tree
2692 */
2693 trans = btrfs_start_transaction(root, 1);
2694 memcpy(&key, &shrink_block_group->key, sizeof(key));
2695
2696 ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
2697 if (ret > 0)
2698 ret = -EIO;
2699 if (ret < 0)
2700 goto out;
2701
2702 leaf = path->nodes[0];
2703 nritems = btrfs_header_nritems(leaf);
2704 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
2705 kfree(shrink_block_group);
2706
2707 clear_extent_bits(&info->block_group_cache, found_key.objectid,
2708 found_key.objectid + found_key.offset - 1,
2709 (unsigned int)-1, GFP_NOFS);
2710
2711 btrfs_del_item(trans, root, path);
2712 clear_extent_dirty(&info->free_space_cache,
2713 shrink_start, shrink_last_byte - 1,
2714 GFP_NOFS);
2715 btrfs_commit_transaction(trans, root);
2716 out:
2717 btrfs_free_path(path);
2718 return ret;
2719 }
2720
2721 int find_first_block_group(struct btrfs_root *root, struct btrfs_path *path,
2722 struct btrfs_key *key)
2723 {
2724 int ret;
2725 struct btrfs_key found_key;
2726 struct extent_buffer *leaf;
2727 int slot;
2728
2729 ret = btrfs_search_slot(NULL, root, key, path, 0, 0);
2730 if (ret < 0)
2731 return ret;
2732 while(1) {
2733 slot = path->slots[0];
2734 leaf = path->nodes[0];
2735 if (slot >= btrfs_header_nritems(leaf)) {
2736 ret = btrfs_next_leaf(root, path);
2737 if (ret == 0)
2738 continue;
2739 if (ret < 0)
2740 goto error;
2741 break;
2742 }
2743 btrfs_item_key_to_cpu(leaf, &found_key, slot);
2744
2745 if (found_key.objectid >= key->objectid &&
2746 found_key.type == BTRFS_BLOCK_GROUP_ITEM_KEY)
2747 return 0;
2748 path->slots[0]++;
2749 }
2750 ret = -ENOENT;
2751 error:
2752 return ret;
2753 }
2754
2755 int btrfs_read_block_groups(struct btrfs_root *root)
2756 {
2757 struct btrfs_path *path;
2758 int ret;
2759 int bit;
2760 struct btrfs_block_group_cache *cache;
2761 struct btrfs_fs_info *info = root->fs_info;
2762 struct btrfs_space_info *space_info;
2763 struct extent_io_tree *block_group_cache;
2764 struct btrfs_key key;
2765 struct btrfs_key found_key;
2766 struct extent_buffer *leaf;
2767
2768 block_group_cache = &info->block_group_cache;
2769 root = info->extent_root;
2770 key.objectid = 0;
2771 key.offset = 0;
2772 btrfs_set_key_type(&key, BTRFS_BLOCK_GROUP_ITEM_KEY);
2773 path = btrfs_alloc_path();
2774 if (!path)
2775 return -ENOMEM;
2776
2777 while(1) {
2778 ret = find_first_block_group(root, path, &key);
2779 if (ret > 0) {
2780 ret = 0;
2781 goto error;
2782 }
2783 if (ret != 0)
2784 goto error;
2785
2786 leaf = path->nodes[0];
2787 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
2788 cache = kzalloc(sizeof(*cache), GFP_NOFS);
2789 if (!cache) {
2790 ret = -ENOMEM;
2791 break;
2792 }
2793
2794 read_extent_buffer(leaf, &cache->item,
2795 btrfs_item_ptr_offset(leaf, path->slots[0]),
2796 sizeof(cache->item));
2797 memcpy(&cache->key, &found_key, sizeof(found_key));
2798
2799 key.objectid = found_key.objectid + found_key.offset;
2800 btrfs_release_path(root, path);
2801 cache->flags = btrfs_block_group_flags(&cache->item);
2802 bit = 0;
2803 if (cache->flags & BTRFS_BLOCK_GROUP_DATA) {
2804 bit = BLOCK_GROUP_DATA;
2805 } else if (cache->flags & BTRFS_BLOCK_GROUP_SYSTEM) {
2806 bit = BLOCK_GROUP_SYSTEM;
2807 } else if (cache->flags & BTRFS_BLOCK_GROUP_METADATA) {
2808 bit = BLOCK_GROUP_METADATA;
2809 }
2810 set_avail_alloc_bits(info, cache->flags);
2811
2812 ret = update_space_info(info, cache->flags, found_key.offset,
2813 btrfs_block_group_used(&cache->item),
2814 &space_info);
2815 BUG_ON(ret);
2816 cache->space_info = space_info;
2817
2818 /* use EXTENT_LOCKED to prevent merging */
2819 set_extent_bits(block_group_cache, found_key.objectid,
2820 found_key.objectid + found_key.offset - 1,
2821 bit | EXTENT_LOCKED, GFP_NOFS);
2822 set_state_private(block_group_cache, found_key.objectid,
2823 (unsigned long)cache);
2824
2825 if (key.objectid >=
2826 btrfs_super_total_bytes(&info->super_copy))
2827 break;
2828 }
2829 ret = 0;
2830 error:
2831 btrfs_free_path(path);
2832 return ret;
2833 }
2834
2835 int btrfs_make_block_group(struct btrfs_trans_handle *trans,
2836 struct btrfs_root *root, u64 bytes_used,
2837 u64 type, u64 chunk_objectid, u64 chunk_offset,
2838 u64 size)
2839 {
2840 int ret;
2841 int bit = 0;
2842 struct btrfs_root *extent_root;
2843 struct btrfs_block_group_cache *cache;
2844 struct extent_io_tree *block_group_cache;
2845
2846 extent_root = root->fs_info->extent_root;
2847 block_group_cache = &root->fs_info->block_group_cache;
2848
2849 cache = kzalloc(sizeof(*cache), GFP_NOFS);
2850 BUG_ON(!cache);
2851 cache->key.objectid = chunk_offset;
2852 cache->key.offset = size;
2853
2854 btrfs_set_key_type(&cache->key, BTRFS_BLOCK_GROUP_ITEM_KEY);
2855 memset(&cache->item, 0, sizeof(cache->item));
2856 btrfs_set_block_group_used(&cache->item, bytes_used);
2857 btrfs_set_block_group_chunk_objectid(&cache->item, chunk_objectid);
2858 cache->flags = type;
2859 btrfs_set_block_group_flags(&cache->item, type);
2860
2861 ret = update_space_info(root->fs_info, cache->flags, size, bytes_used,
2862 &cache->space_info);
2863 BUG_ON(ret);
2864
2865 bit = block_group_state_bits(type);
2866 set_extent_bits(block_group_cache, chunk_offset,
2867 chunk_offset + size - 1,
2868 bit | EXTENT_LOCKED, GFP_NOFS);
2869
2870 set_state_private(block_group_cache, chunk_offset,
2871 (unsigned long)cache);
2872 ret = btrfs_insert_item(trans, extent_root, &cache->key, &cache->item,
2873 sizeof(cache->item));
2874 BUG_ON(ret);
2875
2876 finish_current_insert(trans, extent_root);
2877 ret = del_pending_extents(trans, extent_root);
2878 BUG_ON(ret);
2879 set_avail_alloc_bits(extent_root->fs_info, type);
2880 return 0;
2881 }
Linux kernel - Deliverables
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