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5e0857ffbc354e03e9bd970e526c8c92169cf8c2
[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 #include "locking.h"
29
30 #define BLOCK_GROUP_DATA EXTENT_WRITEBACK
31 #define BLOCK_GROUP_METADATA EXTENT_UPTODATE
32 #define BLOCK_GROUP_SYSTEM EXTENT_NEW
33
34 #define BLOCK_GROUP_DIRTY EXTENT_DIRTY
35
36 static int finish_current_insert(struct btrfs_trans_handle *trans, struct
37 btrfs_root *extent_root);
38 static int del_pending_extents(struct btrfs_trans_handle *trans, struct
39 btrfs_root *extent_root);
40 static struct btrfs_block_group_cache *
41 __btrfs_find_block_group(struct btrfs_root *root,
42 struct btrfs_block_group_cache *hint,
43 u64 search_start, int data, int owner);
44
45 void maybe_lock_mutex(struct btrfs_root *root)
46 {
47 if (root != root->fs_info->extent_root &&
48 root != root->fs_info->chunk_root &&
49 root != root->fs_info->dev_root) {
50 mutex_lock(&root->fs_info->alloc_mutex);
51 }
52 }
53
54 void maybe_unlock_mutex(struct btrfs_root *root)
55 {
56 if (root != root->fs_info->extent_root &&
57 root != root->fs_info->chunk_root &&
58 root != root->fs_info->dev_root) {
59 mutex_unlock(&root->fs_info->alloc_mutex);
60 }
61 }
62
63 static int cache_block_group(struct btrfs_root *root,
64 struct btrfs_block_group_cache *block_group)
65 {
66 struct btrfs_path *path;
67 int ret;
68 struct btrfs_key key;
69 struct extent_buffer *leaf;
70 struct extent_io_tree *free_space_cache;
71 int slot;
72 u64 last = 0;
73 u64 hole_size;
74 u64 first_free;
75 int found = 0;
76
77 if (!block_group)
78 return 0;
79
80 root = root->fs_info->extent_root;
81 free_space_cache = &root->fs_info->free_space_cache;
82
83 if (block_group->cached)
84 return 0;
85
86 path = btrfs_alloc_path();
87 if (!path)
88 return -ENOMEM;
89
90 path->reada = 2;
91 /*
92 * we get into deadlocks with paths held by callers of this function.
93 * since the alloc_mutex is protecting things right now, just
94 * skip the locking here
95 */
96 path->skip_locking = 1;
97 first_free = block_group->key.objectid;
98 key.objectid = block_group->key.objectid;
99 key.offset = 0;
100 btrfs_set_key_type(&key, BTRFS_EXTENT_ITEM_KEY);
101 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
102 if (ret < 0)
103 return ret;
104 ret = btrfs_previous_item(root, path, 0, BTRFS_EXTENT_ITEM_KEY);
105 if (ret < 0)
106 return ret;
107 if (ret == 0) {
108 leaf = path->nodes[0];
109 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
110 if (key.objectid + key.offset > first_free)
111 first_free = key.objectid + key.offset;
112 }
113 while(1) {
114 leaf = path->nodes[0];
115 slot = path->slots[0];
116 if (slot >= btrfs_header_nritems(leaf)) {
117 ret = btrfs_next_leaf(root, path);
118 if (ret < 0)
119 goto err;
120 if (ret == 0) {
121 continue;
122 } else {
123 break;
124 }
125 }
126 btrfs_item_key_to_cpu(leaf, &key, slot);
127 if (key.objectid < block_group->key.objectid) {
128 goto next;
129 }
130 if (key.objectid >= block_group->key.objectid +
131 block_group->key.offset) {
132 break;
133 }
134
135 if (btrfs_key_type(&key) == BTRFS_EXTENT_ITEM_KEY) {
136 if (!found) {
137 last = first_free;
138 found = 1;
139 }
140 if (key.objectid > last) {
141 hole_size = key.objectid - last;
142 set_extent_dirty(free_space_cache, last,
143 last + hole_size - 1,
144 GFP_NOFS);
145 }
146 last = key.objectid + key.offset;
147 }
148 next:
149 path->slots[0]++;
150 }
151
152 if (!found)
153 last = first_free;
154 if (block_group->key.objectid +
155 block_group->key.offset > last) {
156 hole_size = block_group->key.objectid +
157 block_group->key.offset - last;
158 set_extent_dirty(free_space_cache, last,
159 last + hole_size - 1, GFP_NOFS);
160 }
161 block_group->cached = 1;
162 err:
163 btrfs_free_path(path);
164 return 0;
165 }
166
167 struct btrfs_block_group_cache *btrfs_lookup_first_block_group(struct
168 btrfs_fs_info *info,
169 u64 bytenr)
170 {
171 struct extent_io_tree *block_group_cache;
172 struct btrfs_block_group_cache *block_group = NULL;
173 u64 ptr;
174 u64 start;
175 u64 end;
176 int ret;
177
178 bytenr = max_t(u64, bytenr,
179 BTRFS_SUPER_INFO_OFFSET + BTRFS_SUPER_INFO_SIZE);
180 block_group_cache = &info->block_group_cache;
181 ret = find_first_extent_bit(block_group_cache,
182 bytenr, &start, &end,
183 BLOCK_GROUP_DATA | BLOCK_GROUP_METADATA |
184 BLOCK_GROUP_SYSTEM);
185 if (ret) {
186 return NULL;
187 }
188 ret = get_state_private(block_group_cache, start, &ptr);
189 if (ret)
190 return NULL;
191
192 block_group = (struct btrfs_block_group_cache *)(unsigned long)ptr;
193 return block_group;
194 }
195
196 struct btrfs_block_group_cache *btrfs_lookup_block_group(struct
197 btrfs_fs_info *info,
198 u64 bytenr)
199 {
200 struct extent_io_tree *block_group_cache;
201 struct btrfs_block_group_cache *block_group = NULL;
202 u64 ptr;
203 u64 start;
204 u64 end;
205 int ret;
206
207 bytenr = max_t(u64, bytenr,
208 BTRFS_SUPER_INFO_OFFSET + BTRFS_SUPER_INFO_SIZE);
209 block_group_cache = &info->block_group_cache;
210 ret = find_first_extent_bit(block_group_cache,
211 bytenr, &start, &end,
212 BLOCK_GROUP_DATA | BLOCK_GROUP_METADATA |
213 BLOCK_GROUP_SYSTEM);
214 if (ret) {
215 return NULL;
216 }
217 ret = get_state_private(block_group_cache, start, &ptr);
218 if (ret)
219 return NULL;
220
221 block_group = (struct btrfs_block_group_cache *)(unsigned long)ptr;
222 if (block_group->key.objectid <= bytenr && bytenr <
223 block_group->key.objectid + block_group->key.offset)
224 return block_group;
225 return NULL;
226 }
227
228 static int block_group_bits(struct btrfs_block_group_cache *cache, u64 bits)
229 {
230 return (cache->flags & bits) == bits;
231 }
232
233 static int noinline find_search_start(struct btrfs_root *root,
234 struct btrfs_block_group_cache **cache_ret,
235 u64 *start_ret, u64 num, int data)
236 {
237 int ret;
238 struct btrfs_block_group_cache *cache = *cache_ret;
239 struct extent_io_tree *free_space_cache;
240 struct extent_state *state;
241 u64 last;
242 u64 start = 0;
243 u64 cache_miss = 0;
244 u64 total_fs_bytes;
245 u64 search_start = *start_ret;
246 int wrapped = 0;
247
248 total_fs_bytes = btrfs_super_total_bytes(&root->fs_info->super_copy);
249 free_space_cache = &root->fs_info->free_space_cache;
250
251 if (!cache)
252 goto out;
253
254 again:
255 ret = cache_block_group(root, cache);
256 if (ret) {
257 goto out;
258 }
259
260 last = max(search_start, cache->key.objectid);
261 if (!block_group_bits(cache, data) || cache->ro)
262 goto new_group;
263
264 spin_lock_irq(&free_space_cache->lock);
265 state = find_first_extent_bit_state(free_space_cache, last, EXTENT_DIRTY);
266 while(1) {
267 if (!state) {
268 if (!cache_miss)
269 cache_miss = last;
270 spin_unlock_irq(&free_space_cache->lock);
271 goto new_group;
272 }
273
274 start = max(last, state->start);
275 last = state->end + 1;
276 if (last - start < num) {
277 do {
278 state = extent_state_next(state);
279 } while(state && !(state->state & EXTENT_DIRTY));
280 continue;
281 }
282 spin_unlock_irq(&free_space_cache->lock);
283 if (cache->ro) {
284 goto new_group;
285 }
286 if (start + num > cache->key.objectid + cache->key.offset)
287 goto new_group;
288 if (!block_group_bits(cache, data)) {
289 printk("block group bits don't match %Lu %d\n", cache->flags, data);
290 }
291 *start_ret = start;
292 return 0;
293 }
294 out:
295 cache = btrfs_lookup_block_group(root->fs_info, search_start);
296 if (!cache) {
297 printk("Unable to find block group for %Lu\n", search_start);
298 WARN_ON(1);
299 }
300 return -ENOSPC;
301
302 new_group:
303 last = cache->key.objectid + cache->key.offset;
304 wrapped:
305 cache = btrfs_lookup_first_block_group(root->fs_info, last);
306 if (!cache || cache->key.objectid >= total_fs_bytes) {
307 no_cache:
308 if (!wrapped) {
309 wrapped = 1;
310 last = search_start;
311 goto wrapped;
312 }
313 goto out;
314 }
315 if (cache_miss && !cache->cached) {
316 cache_block_group(root, cache);
317 last = cache_miss;
318 cache = btrfs_lookup_first_block_group(root->fs_info, last);
319 }
320 cache_miss = 0;
321 cache = __btrfs_find_block_group(root, cache, last, data, 0);
322 if (!cache)
323 goto no_cache;
324 *cache_ret = cache;
325 goto again;
326 }
327
328 static u64 div_factor(u64 num, int factor)
329 {
330 if (factor == 10)
331 return num;
332 num *= factor;
333 do_div(num, 10);
334 return num;
335 }
336
337 static int block_group_state_bits(u64 flags)
338 {
339 int bits = 0;
340 if (flags & BTRFS_BLOCK_GROUP_DATA)
341 bits |= BLOCK_GROUP_DATA;
342 if (flags & BTRFS_BLOCK_GROUP_METADATA)
343 bits |= BLOCK_GROUP_METADATA;
344 if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
345 bits |= BLOCK_GROUP_SYSTEM;
346 return bits;
347 }
348
349 static struct btrfs_block_group_cache *
350 __btrfs_find_block_group(struct btrfs_root *root,
351 struct btrfs_block_group_cache *hint,
352 u64 search_start, int data, int owner)
353 {
354 struct btrfs_block_group_cache *cache;
355 struct extent_io_tree *block_group_cache;
356 struct btrfs_block_group_cache *found_group = NULL;
357 struct btrfs_fs_info *info = root->fs_info;
358 u64 used;
359 u64 last = 0;
360 u64 start;
361 u64 end;
362 u64 free_check;
363 u64 ptr;
364 int bit;
365 int ret;
366 int full_search = 0;
367 int factor = 10;
368 int wrapped = 0;
369
370 block_group_cache = &info->block_group_cache;
371
372 if (data & BTRFS_BLOCK_GROUP_METADATA)
373 factor = 9;
374
375 bit = block_group_state_bits(data);
376
377 if (search_start) {
378 struct btrfs_block_group_cache *shint;
379 shint = btrfs_lookup_first_block_group(info, search_start);
380 if (shint && block_group_bits(shint, data) && !shint->ro) {
381 used = btrfs_block_group_used(&shint->item);
382 if (used + shint->pinned <
383 div_factor(shint->key.offset, factor)) {
384 return shint;
385 }
386 }
387 }
388 if (hint && !hint->ro && block_group_bits(hint, data)) {
389 used = btrfs_block_group_used(&hint->item);
390 if (used + hint->pinned <
391 div_factor(hint->key.offset, factor)) {
392 return hint;
393 }
394 last = hint->key.objectid + hint->key.offset;
395 } else {
396 if (hint)
397 last = max(hint->key.objectid, search_start);
398 else
399 last = search_start;
400 }
401 again:
402 while(1) {
403 ret = find_first_extent_bit(block_group_cache, last,
404 &start, &end, bit);
405 if (ret)
406 break;
407
408 ret = get_state_private(block_group_cache, start, &ptr);
409 if (ret) {
410 last = end + 1;
411 continue;
412 }
413
414 cache = (struct btrfs_block_group_cache *)(unsigned long)ptr;
415 last = cache->key.objectid + cache->key.offset;
416 used = btrfs_block_group_used(&cache->item);
417
418 if (!cache->ro && block_group_bits(cache, data)) {
419 free_check = div_factor(cache->key.offset, factor);
420 if (used + cache->pinned < free_check) {
421 found_group = cache;
422 goto found;
423 }
424 }
425 cond_resched();
426 }
427 if (!wrapped) {
428 last = search_start;
429 wrapped = 1;
430 goto again;
431 }
432 if (!full_search && factor < 10) {
433 last = search_start;
434 full_search = 1;
435 factor = 10;
436 goto again;
437 }
438 found:
439 return found_group;
440 }
441
442 struct btrfs_block_group_cache *btrfs_find_block_group(struct btrfs_root *root,
443 struct btrfs_block_group_cache
444 *hint, u64 search_start,
445 int data, int owner)
446 {
447
448 struct btrfs_block_group_cache *ret;
449 mutex_lock(&root->fs_info->alloc_mutex);
450 ret = __btrfs_find_block_group(root, hint, search_start, data, owner);
451 mutex_unlock(&root->fs_info->alloc_mutex);
452 return ret;
453 }
454 static u64 hash_extent_ref(u64 root_objectid, u64 ref_generation,
455 u64 owner, u64 owner_offset)
456 {
457 u32 high_crc = ~(u32)0;
458 u32 low_crc = ~(u32)0;
459 __le64 lenum;
460 lenum = cpu_to_le64(root_objectid);
461 high_crc = btrfs_crc32c(high_crc, &lenum, sizeof(lenum));
462 lenum = cpu_to_le64(ref_generation);
463 low_crc = btrfs_crc32c(low_crc, &lenum, sizeof(lenum));
464 if (owner >= BTRFS_FIRST_FREE_OBJECTID) {
465 lenum = cpu_to_le64(owner);
466 low_crc = btrfs_crc32c(low_crc, &lenum, sizeof(lenum));
467 lenum = cpu_to_le64(owner_offset);
468 low_crc = btrfs_crc32c(low_crc, &lenum, sizeof(lenum));
469 }
470 return ((u64)high_crc << 32) | (u64)low_crc;
471 }
472
473 static int match_extent_ref(struct extent_buffer *leaf,
474 struct btrfs_extent_ref *disk_ref,
475 struct btrfs_extent_ref *cpu_ref)
476 {
477 int ret;
478 int len;
479
480 if (cpu_ref->objectid)
481 len = sizeof(*cpu_ref);
482 else
483 len = 2 * sizeof(u64);
484 ret = memcmp_extent_buffer(leaf, cpu_ref, (unsigned long)disk_ref,
485 len);
486 return ret == 0;
487 }
488
489 static int noinline lookup_extent_backref(struct btrfs_trans_handle *trans,
490 struct btrfs_root *root,
491 struct btrfs_path *path, u64 bytenr,
492 u64 root_objectid,
493 u64 ref_generation, u64 owner,
494 u64 owner_offset, int del)
495 {
496 u64 hash;
497 struct btrfs_key key;
498 struct btrfs_key found_key;
499 struct btrfs_extent_ref ref;
500 struct extent_buffer *leaf;
501 struct btrfs_extent_ref *disk_ref;
502 int ret;
503 int ret2;
504
505 btrfs_set_stack_ref_root(&ref, root_objectid);
506 btrfs_set_stack_ref_generation(&ref, ref_generation);
507 btrfs_set_stack_ref_objectid(&ref, owner);
508 btrfs_set_stack_ref_offset(&ref, owner_offset);
509
510 hash = hash_extent_ref(root_objectid, ref_generation, owner,
511 owner_offset);
512 key.offset = hash;
513 key.objectid = bytenr;
514 key.type = BTRFS_EXTENT_REF_KEY;
515
516 while (1) {
517 ret = btrfs_search_slot(trans, root, &key, path,
518 del ? -1 : 0, del);
519 if (ret < 0)
520 goto out;
521 leaf = path->nodes[0];
522 if (ret != 0) {
523 u32 nritems = btrfs_header_nritems(leaf);
524 if (path->slots[0] >= nritems) {
525 ret2 = btrfs_next_leaf(root, path);
526 if (ret2)
527 goto out;
528 leaf = path->nodes[0];
529 }
530 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
531 if (found_key.objectid != bytenr ||
532 found_key.type != BTRFS_EXTENT_REF_KEY)
533 goto out;
534 key.offset = found_key.offset;
535 if (del) {
536 btrfs_release_path(root, path);
537 continue;
538 }
539 }
540 disk_ref = btrfs_item_ptr(path->nodes[0],
541 path->slots[0],
542 struct btrfs_extent_ref);
543 if (match_extent_ref(path->nodes[0], disk_ref, &ref)) {
544 ret = 0;
545 goto out;
546 }
547 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
548 key.offset = found_key.offset + 1;
549 btrfs_release_path(root, path);
550 }
551 out:
552 return ret;
553 }
554
555 /*
556 * Back reference rules. Back refs have three main goals:
557 *
558 * 1) differentiate between all holders of references to an extent so that
559 * when a reference is dropped we can make sure it was a valid reference
560 * before freeing the extent.
561 *
562 * 2) Provide enough information to quickly find the holders of an extent
563 * if we notice a given block is corrupted or bad.
564 *
565 * 3) Make it easy to migrate blocks for FS shrinking or storage pool
566 * maintenance. This is actually the same as #2, but with a slightly
567 * different use case.
568 *
569 * File extents can be referenced by:
570 *
571 * - multiple snapshots, subvolumes, or different generations in one subvol
572 * - different files inside a single subvolume (in theory, not implemented yet)
573 * - different offsets inside a file (bookend extents in file.c)
574 *
575 * The extent ref structure has fields for:
576 *
577 * - Objectid of the subvolume root
578 * - Generation number of the tree holding the reference
579 * - objectid of the file holding the reference
580 * - offset in the file corresponding to the key holding the reference
581 *
582 * When a file extent is allocated the fields are filled in:
583 * (root_key.objectid, trans->transid, inode objectid, offset in file)
584 *
585 * When a leaf is cow'd new references are added for every file extent found
586 * in the leaf. It looks the same as the create case, but trans->transid
587 * will be different when the block is cow'd.
588 *
589 * (root_key.objectid, trans->transid, inode objectid, offset in file)
590 *
591 * When a file extent is removed either during snapshot deletion or file
592 * truncation, the corresponding back reference is found
593 * by searching for:
594 *
595 * (btrfs_header_owner(leaf), btrfs_header_generation(leaf),
596 * inode objectid, offset in file)
597 *
598 * Btree extents can be referenced by:
599 *
600 * - Different subvolumes
601 * - Different generations of the same subvolume
602 *
603 * Storing sufficient information for a full reverse mapping of a btree
604 * block would require storing the lowest key of the block in the backref,
605 * and it would require updating that lowest key either before write out or
606 * every time it changed. Instead, the objectid of the lowest key is stored
607 * along with the level of the tree block. This provides a hint
608 * about where in the btree the block can be found. Searches through the
609 * btree only need to look for a pointer to that block, so they stop one
610 * level higher than the level recorded in the backref.
611 *
612 * Some btrees do not do reference counting on their extents. These
613 * include the extent tree and the tree of tree roots. Backrefs for these
614 * trees always have a generation of zero.
615 *
616 * When a tree block is created, back references are inserted:
617 *
618 * (root->root_key.objectid, trans->transid or zero, level, lowest_key_objectid)
619 *
620 * When a tree block is cow'd in a reference counted root,
621 * new back references are added for all the blocks it points to.
622 * These are of the form (trans->transid will have increased since creation):
623 *
624 * (root->root_key.objectid, trans->transid, level, lowest_key_objectid)
625 *
626 * Because the lowest_key_objectid and the level are just hints
627 * they are not used when backrefs are deleted. When a backref is deleted:
628 *
629 * if backref was for a tree root:
630 * root_objectid = root->root_key.objectid
631 * else
632 * root_objectid = btrfs_header_owner(parent)
633 *
634 * (root_objectid, btrfs_header_generation(parent) or zero, 0, 0)
635 *
636 * Back Reference Key hashing:
637 *
638 * Back references have four fields, each 64 bits long. Unfortunately,
639 * This is hashed into a single 64 bit number and placed into the key offset.
640 * The key objectid corresponds to the first byte in the extent, and the
641 * key type is set to BTRFS_EXTENT_REF_KEY
642 */
643 int btrfs_insert_extent_backref(struct btrfs_trans_handle *trans,
644 struct btrfs_root *root,
645 struct btrfs_path *path, u64 bytenr,
646 u64 root_objectid, u64 ref_generation,
647 u64 owner, u64 owner_offset)
648 {
649 u64 hash;
650 struct btrfs_key key;
651 struct btrfs_extent_ref ref;
652 struct btrfs_extent_ref *disk_ref;
653 int ret;
654
655 btrfs_set_stack_ref_root(&ref, root_objectid);
656 btrfs_set_stack_ref_generation(&ref, ref_generation);
657 btrfs_set_stack_ref_objectid(&ref, owner);
658 btrfs_set_stack_ref_offset(&ref, owner_offset);
659
660 hash = hash_extent_ref(root_objectid, ref_generation, owner,
661 owner_offset);
662 key.offset = hash;
663 key.objectid = bytenr;
664 key.type = BTRFS_EXTENT_REF_KEY;
665
666 ret = btrfs_insert_empty_item(trans, root, path, &key, sizeof(ref));
667 while (ret == -EEXIST) {
668 disk_ref = btrfs_item_ptr(path->nodes[0], path->slots[0],
669 struct btrfs_extent_ref);
670 if (match_extent_ref(path->nodes[0], disk_ref, &ref))
671 goto out;
672 key.offset++;
673 btrfs_release_path(root, path);
674 ret = btrfs_insert_empty_item(trans, root, path, &key,
675 sizeof(ref));
676 }
677 if (ret)
678 goto out;
679 disk_ref = btrfs_item_ptr(path->nodes[0], path->slots[0],
680 struct btrfs_extent_ref);
681 write_extent_buffer(path->nodes[0], &ref, (unsigned long)disk_ref,
682 sizeof(ref));
683 btrfs_mark_buffer_dirty(path->nodes[0]);
684 out:
685 btrfs_release_path(root, path);
686 return ret;
687 }
688
689 static int __btrfs_inc_extent_ref(struct btrfs_trans_handle *trans,
690 struct btrfs_root *root,
691 u64 bytenr, u64 num_bytes,
692 u64 root_objectid, u64 ref_generation,
693 u64 owner, u64 owner_offset)
694 {
695 struct btrfs_path *path;
696 int ret;
697 struct btrfs_key key;
698 struct extent_buffer *l;
699 struct btrfs_extent_item *item;
700 u32 refs;
701
702 WARN_ON(num_bytes < root->sectorsize);
703 path = btrfs_alloc_path();
704 if (!path)
705 return -ENOMEM;
706
707 path->reada = 1;
708 key.objectid = bytenr;
709 btrfs_set_key_type(&key, BTRFS_EXTENT_ITEM_KEY);
710 key.offset = num_bytes;
711 ret = btrfs_search_slot(trans, root->fs_info->extent_root, &key, path,
712 0, 1);
713 if (ret < 0)
714 return ret;
715 if (ret != 0) {
716 BUG();
717 }
718 BUG_ON(ret != 0);
719 l = path->nodes[0];
720 item = btrfs_item_ptr(l, path->slots[0], struct btrfs_extent_item);
721 refs = btrfs_extent_refs(l, item);
722 btrfs_set_extent_refs(l, item, refs + 1);
723 btrfs_mark_buffer_dirty(path->nodes[0]);
724
725 btrfs_release_path(root->fs_info->extent_root, path);
726
727 path->reada = 1;
728 ret = btrfs_insert_extent_backref(trans, root->fs_info->extent_root,
729 path, bytenr, root_objectid,
730 ref_generation, owner, owner_offset);
731 BUG_ON(ret);
732 finish_current_insert(trans, root->fs_info->extent_root);
733 del_pending_extents(trans, root->fs_info->extent_root);
734
735 btrfs_free_path(path);
736 return 0;
737 }
738
739 int btrfs_inc_extent_ref(struct btrfs_trans_handle *trans,
740 struct btrfs_root *root,
741 u64 bytenr, u64 num_bytes,
742 u64 root_objectid, u64 ref_generation,
743 u64 owner, u64 owner_offset)
744 {
745 int ret;
746
747 mutex_lock(&root->fs_info->alloc_mutex);
748 ret = __btrfs_inc_extent_ref(trans, root, bytenr, num_bytes,
749 root_objectid, ref_generation,
750 owner, owner_offset);
751 mutex_unlock(&root->fs_info->alloc_mutex);
752 return ret;
753 }
754
755 int btrfs_extent_post_op(struct btrfs_trans_handle *trans,
756 struct btrfs_root *root)
757 {
758 finish_current_insert(trans, root->fs_info->extent_root);
759 del_pending_extents(trans, root->fs_info->extent_root);
760 return 0;
761 }
762
763 static int lookup_extent_ref(struct btrfs_trans_handle *trans,
764 struct btrfs_root *root, u64 bytenr,
765 u64 num_bytes, u32 *refs)
766 {
767 struct btrfs_path *path;
768 int ret;
769 struct btrfs_key key;
770 struct extent_buffer *l;
771 struct btrfs_extent_item *item;
772
773 WARN_ON(num_bytes < root->sectorsize);
774 path = btrfs_alloc_path();
775 path->reada = 1;
776 key.objectid = bytenr;
777 key.offset = num_bytes;
778 btrfs_set_key_type(&key, BTRFS_EXTENT_ITEM_KEY);
779 ret = btrfs_search_slot(trans, root->fs_info->extent_root, &key, path,
780 0, 0);
781 if (ret < 0)
782 goto out;
783 if (ret != 0) {
784 btrfs_print_leaf(root, path->nodes[0]);
785 printk("failed to find block number %Lu\n", bytenr);
786 BUG();
787 }
788 l = path->nodes[0];
789 item = btrfs_item_ptr(l, path->slots[0], struct btrfs_extent_item);
790 *refs = btrfs_extent_refs(l, item);
791 out:
792 btrfs_free_path(path);
793 return 0;
794 }
795
796 u32 btrfs_count_snapshots_in_path(struct btrfs_root *root,
797 struct btrfs_path *count_path,
798 u64 expected_owner,
799 u64 first_extent)
800 {
801 struct btrfs_root *extent_root = root->fs_info->extent_root;
802 struct btrfs_path *path;
803 u64 bytenr;
804 u64 found_objectid;
805 u64 found_owner;
806 u64 root_objectid = root->root_key.objectid;
807 u32 total_count = 0;
808 u32 extent_refs;
809 u32 cur_count;
810 u32 nritems;
811 int ret;
812 struct btrfs_key key;
813 struct btrfs_key found_key;
814 struct extent_buffer *l;
815 struct btrfs_extent_item *item;
816 struct btrfs_extent_ref *ref_item;
817 int level = -1;
818
819 /* FIXME, needs locking */
820 BUG();
821
822 mutex_lock(&root->fs_info->alloc_mutex);
823 path = btrfs_alloc_path();
824 again:
825 if (level == -1)
826 bytenr = first_extent;
827 else
828 bytenr = count_path->nodes[level]->start;
829
830 cur_count = 0;
831 key.objectid = bytenr;
832 key.offset = 0;
833
834 btrfs_set_key_type(&key, BTRFS_EXTENT_ITEM_KEY);
835 ret = btrfs_search_slot(NULL, extent_root, &key, path, 0, 0);
836 if (ret < 0)
837 goto out;
838 BUG_ON(ret == 0);
839
840 l = path->nodes[0];
841 btrfs_item_key_to_cpu(l, &found_key, path->slots[0]);
842
843 if (found_key.objectid != bytenr ||
844 found_key.type != BTRFS_EXTENT_ITEM_KEY) {
845 goto out;
846 }
847
848 item = btrfs_item_ptr(l, path->slots[0], struct btrfs_extent_item);
849 extent_refs = btrfs_extent_refs(l, item);
850 while (1) {
851 l = path->nodes[0];
852 nritems = btrfs_header_nritems(l);
853 if (path->slots[0] >= nritems) {
854 ret = btrfs_next_leaf(extent_root, path);
855 if (ret == 0)
856 continue;
857 break;
858 }
859 btrfs_item_key_to_cpu(l, &found_key, path->slots[0]);
860 if (found_key.objectid != bytenr)
861 break;
862
863 if (found_key.type != BTRFS_EXTENT_REF_KEY) {
864 path->slots[0]++;
865 continue;
866 }
867
868 cur_count++;
869 ref_item = btrfs_item_ptr(l, path->slots[0],
870 struct btrfs_extent_ref);
871 found_objectid = btrfs_ref_root(l, ref_item);
872
873 if (found_objectid != root_objectid) {
874 total_count = 2;
875 goto out;
876 }
877 if (level == -1) {
878 found_owner = btrfs_ref_objectid(l, ref_item);
879 if (found_owner != expected_owner) {
880 total_count = 2;
881 goto out;
882 }
883 /*
884 * nasty. we don't count a reference held by
885 * the running transaction. This allows nodatacow
886 * to avoid cow most of the time
887 */
888 if (found_owner >= BTRFS_FIRST_FREE_OBJECTID &&
889 btrfs_ref_generation(l, ref_item) ==
890 root->fs_info->generation) {
891 extent_refs--;
892 }
893 }
894 total_count = 1;
895 path->slots[0]++;
896 }
897 /*
898 * if there is more than one reference against a data extent,
899 * we have to assume the other ref is another snapshot
900 */
901 if (level == -1 && extent_refs > 1) {
902 total_count = 2;
903 goto out;
904 }
905 if (cur_count == 0) {
906 total_count = 0;
907 goto out;
908 }
909 if (level >= 0 && root->node == count_path->nodes[level])
910 goto out;
911 level++;
912 btrfs_release_path(root, path);
913 goto again;
914
915 out:
916 btrfs_free_path(path);
917 mutex_unlock(&root->fs_info->alloc_mutex);
918 return total_count;
919 }
920
921 int btrfs_inc_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root,
922 struct extent_buffer *buf)
923 {
924 u64 bytenr;
925 u32 nritems;
926 struct btrfs_key key;
927 struct btrfs_file_extent_item *fi;
928 int i;
929 int level;
930 int ret;
931 int faili;
932
933 if (!root->ref_cows)
934 return 0;
935
936 mutex_lock(&root->fs_info->alloc_mutex);
937 level = btrfs_header_level(buf);
938 nritems = btrfs_header_nritems(buf);
939 for (i = 0; i < nritems; i++) {
940 if (level == 0) {
941 u64 disk_bytenr;
942 btrfs_item_key_to_cpu(buf, &key, i);
943 if (btrfs_key_type(&key) != BTRFS_EXTENT_DATA_KEY)
944 continue;
945 fi = btrfs_item_ptr(buf, i,
946 struct btrfs_file_extent_item);
947 if (btrfs_file_extent_type(buf, fi) ==
948 BTRFS_FILE_EXTENT_INLINE)
949 continue;
950 disk_bytenr = btrfs_file_extent_disk_bytenr(buf, fi);
951 if (disk_bytenr == 0)
952 continue;
953 ret = __btrfs_inc_extent_ref(trans, root, disk_bytenr,
954 btrfs_file_extent_disk_num_bytes(buf, fi),
955 root->root_key.objectid, trans->transid,
956 key.objectid, key.offset);
957 if (ret) {
958 faili = i;
959 goto fail;
960 }
961 } else {
962 bytenr = btrfs_node_blockptr(buf, i);
963 btrfs_node_key_to_cpu(buf, &key, i);
964 ret = __btrfs_inc_extent_ref(trans, root, bytenr,
965 btrfs_level_size(root, level - 1),
966 root->root_key.objectid,
967 trans->transid,
968 level - 1, key.objectid);
969 if (ret) {
970 faili = i;
971 goto fail;
972 }
973 }
974 }
975 mutex_unlock(&root->fs_info->alloc_mutex);
976 return 0;
977 fail:
978 WARN_ON(1);
979 #if 0
980 for (i =0; i < faili; i++) {
981 if (level == 0) {
982 u64 disk_bytenr;
983 btrfs_item_key_to_cpu(buf, &key, i);
984 if (btrfs_key_type(&key) != BTRFS_EXTENT_DATA_KEY)
985 continue;
986 fi = btrfs_item_ptr(buf, i,
987 struct btrfs_file_extent_item);
988 if (btrfs_file_extent_type(buf, fi) ==
989 BTRFS_FILE_EXTENT_INLINE)
990 continue;
991 disk_bytenr = btrfs_file_extent_disk_bytenr(buf, fi);
992 if (disk_bytenr == 0)
993 continue;
994 err = btrfs_free_extent(trans, root, disk_bytenr,
995 btrfs_file_extent_disk_num_bytes(buf,
996 fi), 0);
997 BUG_ON(err);
998 } else {
999 bytenr = btrfs_node_blockptr(buf, i);
1000 err = btrfs_free_extent(trans, root, bytenr,
1001 btrfs_level_size(root, level - 1), 0);
1002 BUG_ON(err);
1003 }
1004 }
1005 #endif
1006 mutex_unlock(&root->fs_info->alloc_mutex);
1007 return ret;
1008 }
1009
1010 static int write_one_cache_group(struct btrfs_trans_handle *trans,
1011 struct btrfs_root *root,
1012 struct btrfs_path *path,
1013 struct btrfs_block_group_cache *cache)
1014 {
1015 int ret;
1016 int pending_ret;
1017 struct btrfs_root *extent_root = root->fs_info->extent_root;
1018 unsigned long bi;
1019 struct extent_buffer *leaf;
1020
1021 ret = btrfs_search_slot(trans, extent_root, &cache->key, path, 0, 1);
1022 if (ret < 0)
1023 goto fail;
1024 BUG_ON(ret);
1025
1026 leaf = path->nodes[0];
1027 bi = btrfs_item_ptr_offset(leaf, path->slots[0]);
1028 write_extent_buffer(leaf, &cache->item, bi, sizeof(cache->item));
1029 btrfs_mark_buffer_dirty(leaf);
1030 btrfs_release_path(extent_root, path);
1031 fail:
1032 finish_current_insert(trans, extent_root);
1033 pending_ret = del_pending_extents(trans, extent_root);
1034 if (ret)
1035 return ret;
1036 if (pending_ret)
1037 return pending_ret;
1038 return 0;
1039
1040 }
1041
1042 int btrfs_write_dirty_block_groups(struct btrfs_trans_handle *trans,
1043 struct btrfs_root *root)
1044 {
1045 struct extent_io_tree *block_group_cache;
1046 struct btrfs_block_group_cache *cache;
1047 int ret;
1048 int err = 0;
1049 int werr = 0;
1050 struct btrfs_path *path;
1051 u64 last = 0;
1052 u64 start;
1053 u64 end;
1054 u64 ptr;
1055
1056 block_group_cache = &root->fs_info->block_group_cache;
1057 path = btrfs_alloc_path();
1058 if (!path)
1059 return -ENOMEM;
1060
1061 mutex_lock(&root->fs_info->alloc_mutex);
1062 while(1) {
1063 ret = find_first_extent_bit(block_group_cache, last,
1064 &start, &end, BLOCK_GROUP_DIRTY);
1065 if (ret)
1066 break;
1067
1068 last = end + 1;
1069 ret = get_state_private(block_group_cache, start, &ptr);
1070 if (ret)
1071 break;
1072 cache = (struct btrfs_block_group_cache *)(unsigned long)ptr;
1073 err = write_one_cache_group(trans, root,
1074 path, cache);
1075 /*
1076 * if we fail to write the cache group, we want
1077 * to keep it marked dirty in hopes that a later
1078 * write will work
1079 */
1080 if (err) {
1081 werr = err;
1082 continue;
1083 }
1084 clear_extent_bits(block_group_cache, start, end,
1085 BLOCK_GROUP_DIRTY, GFP_NOFS);
1086 }
1087 btrfs_free_path(path);
1088 mutex_unlock(&root->fs_info->alloc_mutex);
1089 return werr;
1090 }
1091
1092 static struct btrfs_space_info *__find_space_info(struct btrfs_fs_info *info,
1093 u64 flags)
1094 {
1095 struct list_head *head = &info->space_info;
1096 struct list_head *cur;
1097 struct btrfs_space_info *found;
1098 list_for_each(cur, head) {
1099 found = list_entry(cur, struct btrfs_space_info, list);
1100 if (found->flags == flags)
1101 return found;
1102 }
1103 return NULL;
1104
1105 }
1106
1107 static int update_space_info(struct btrfs_fs_info *info, u64 flags,
1108 u64 total_bytes, u64 bytes_used,
1109 struct btrfs_space_info **space_info)
1110 {
1111 struct btrfs_space_info *found;
1112
1113 found = __find_space_info(info, flags);
1114 if (found) {
1115 found->total_bytes += total_bytes;
1116 found->bytes_used += bytes_used;
1117 found->full = 0;
1118 WARN_ON(found->total_bytes < found->bytes_used);
1119 *space_info = found;
1120 return 0;
1121 }
1122 found = kmalloc(sizeof(*found), GFP_NOFS);
1123 if (!found)
1124 return -ENOMEM;
1125
1126 list_add(&found->list, &info->space_info);
1127 found->flags = flags;
1128 found->total_bytes = total_bytes;
1129 found->bytes_used = bytes_used;
1130 found->bytes_pinned = 0;
1131 found->full = 0;
1132 found->force_alloc = 0;
1133 *space_info = found;
1134 return 0;
1135 }
1136
1137 static void set_avail_alloc_bits(struct btrfs_fs_info *fs_info, u64 flags)
1138 {
1139 u64 extra_flags = flags & (BTRFS_BLOCK_GROUP_RAID0 |
1140 BTRFS_BLOCK_GROUP_RAID1 |
1141 BTRFS_BLOCK_GROUP_RAID10 |
1142 BTRFS_BLOCK_GROUP_DUP);
1143 if (extra_flags) {
1144 if (flags & BTRFS_BLOCK_GROUP_DATA)
1145 fs_info->avail_data_alloc_bits |= extra_flags;
1146 if (flags & BTRFS_BLOCK_GROUP_METADATA)
1147 fs_info->avail_metadata_alloc_bits |= extra_flags;
1148 if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
1149 fs_info->avail_system_alloc_bits |= extra_flags;
1150 }
1151 }
1152
1153 static u64 reduce_alloc_profile(struct btrfs_root *root, u64 flags)
1154 {
1155 u64 num_devices = root->fs_info->fs_devices->num_devices;
1156
1157 if (num_devices == 1)
1158 flags &= ~(BTRFS_BLOCK_GROUP_RAID1 | BTRFS_BLOCK_GROUP_RAID0);
1159 if (num_devices < 4)
1160 flags &= ~BTRFS_BLOCK_GROUP_RAID10;
1161
1162 if ((flags & BTRFS_BLOCK_GROUP_DUP) &&
1163 (flags & (BTRFS_BLOCK_GROUP_RAID1 |
1164 BTRFS_BLOCK_GROUP_RAID10))) {
1165 flags &= ~BTRFS_BLOCK_GROUP_DUP;
1166 }
1167
1168 if ((flags & BTRFS_BLOCK_GROUP_RAID1) &&
1169 (flags & BTRFS_BLOCK_GROUP_RAID10)) {
1170 flags &= ~BTRFS_BLOCK_GROUP_RAID1;
1171 }
1172
1173 if ((flags & BTRFS_BLOCK_GROUP_RAID0) &&
1174 ((flags & BTRFS_BLOCK_GROUP_RAID1) |
1175 (flags & BTRFS_BLOCK_GROUP_RAID10) |
1176 (flags & BTRFS_BLOCK_GROUP_DUP)))
1177 flags &= ~BTRFS_BLOCK_GROUP_RAID0;
1178 return flags;
1179 }
1180
1181 static int do_chunk_alloc(struct btrfs_trans_handle *trans,
1182 struct btrfs_root *extent_root, u64 alloc_bytes,
1183 u64 flags, int force)
1184 {
1185 struct btrfs_space_info *space_info;
1186 u64 thresh;
1187 u64 start;
1188 u64 num_bytes;
1189 int ret;
1190
1191 flags = reduce_alloc_profile(extent_root, flags);
1192
1193 space_info = __find_space_info(extent_root->fs_info, flags);
1194 if (!space_info) {
1195 ret = update_space_info(extent_root->fs_info, flags,
1196 0, 0, &space_info);
1197 BUG_ON(ret);
1198 }
1199 BUG_ON(!space_info);
1200
1201 if (space_info->force_alloc) {
1202 force = 1;
1203 space_info->force_alloc = 0;
1204 }
1205 if (space_info->full)
1206 goto out;
1207
1208 thresh = div_factor(space_info->total_bytes, 6);
1209 if (!force &&
1210 (space_info->bytes_used + space_info->bytes_pinned + alloc_bytes) <
1211 thresh)
1212 goto out;
1213
1214 mutex_lock(&extent_root->fs_info->chunk_mutex);
1215 ret = btrfs_alloc_chunk(trans, extent_root, &start, &num_bytes, flags);
1216 if (ret == -ENOSPC) {
1217 printk("space info full %Lu\n", flags);
1218 space_info->full = 1;
1219 goto out_unlock;
1220 }
1221 BUG_ON(ret);
1222
1223 ret = btrfs_make_block_group(trans, extent_root, 0, flags,
1224 BTRFS_FIRST_CHUNK_TREE_OBJECTID, start, num_bytes);
1225 BUG_ON(ret);
1226 out_unlock:
1227 mutex_unlock(&extent_root->fs_info->chunk_mutex);
1228 out:
1229 return 0;
1230 }
1231
1232 static int update_block_group(struct btrfs_trans_handle *trans,
1233 struct btrfs_root *root,
1234 u64 bytenr, u64 num_bytes, int alloc,
1235 int mark_free)
1236 {
1237 struct btrfs_block_group_cache *cache;
1238 struct btrfs_fs_info *info = root->fs_info;
1239 u64 total = num_bytes;
1240 u64 old_val;
1241 u64 byte_in_group;
1242 u64 start;
1243 u64 end;
1244
1245 while(total) {
1246 cache = btrfs_lookup_block_group(info, bytenr);
1247 if (!cache) {
1248 return -1;
1249 }
1250 byte_in_group = bytenr - cache->key.objectid;
1251 WARN_ON(byte_in_group > cache->key.offset);
1252 start = cache->key.objectid;
1253 end = start + cache->key.offset - 1;
1254 set_extent_bits(&info->block_group_cache, start, end,
1255 BLOCK_GROUP_DIRTY, GFP_NOFS);
1256
1257 old_val = btrfs_block_group_used(&cache->item);
1258 num_bytes = min(total, cache->key.offset - byte_in_group);
1259 if (alloc) {
1260 old_val += num_bytes;
1261 cache->space_info->bytes_used += num_bytes;
1262 } else {
1263 old_val -= num_bytes;
1264 cache->space_info->bytes_used -= num_bytes;
1265 if (mark_free) {
1266 set_extent_dirty(&info->free_space_cache,
1267 bytenr, bytenr + num_bytes - 1,
1268 GFP_NOFS);
1269 }
1270 }
1271 btrfs_set_block_group_used(&cache->item, old_val);
1272 total -= num_bytes;
1273 bytenr += num_bytes;
1274 }
1275 return 0;
1276 }
1277
1278 static u64 first_logical_byte(struct btrfs_root *root, u64 search_start)
1279 {
1280 u64 start;
1281 u64 end;
1282 int ret;
1283 ret = find_first_extent_bit(&root->fs_info->block_group_cache,
1284 search_start, &start, &end,
1285 BLOCK_GROUP_DATA | BLOCK_GROUP_METADATA |
1286 BLOCK_GROUP_SYSTEM);
1287 if (ret)
1288 return 0;
1289 return start;
1290 }
1291
1292
1293 static int update_pinned_extents(struct btrfs_root *root,
1294 u64 bytenr, u64 num, int pin)
1295 {
1296 u64 len;
1297 struct btrfs_block_group_cache *cache;
1298 struct btrfs_fs_info *fs_info = root->fs_info;
1299
1300 if (pin) {
1301 set_extent_dirty(&fs_info->pinned_extents,
1302 bytenr, bytenr + num - 1, GFP_NOFS);
1303 } else {
1304 clear_extent_dirty(&fs_info->pinned_extents,
1305 bytenr, bytenr + num - 1, GFP_NOFS);
1306 }
1307 while (num > 0) {
1308 cache = btrfs_lookup_block_group(fs_info, bytenr);
1309 if (!cache) {
1310 u64 first = first_logical_byte(root, bytenr);
1311 WARN_ON(first < bytenr);
1312 len = min(first - bytenr, num);
1313 } else {
1314 len = min(num, cache->key.offset -
1315 (bytenr - cache->key.objectid));
1316 }
1317 if (pin) {
1318 if (cache) {
1319 cache->pinned += len;
1320 cache->space_info->bytes_pinned += len;
1321 }
1322 fs_info->total_pinned += len;
1323 } else {
1324 if (cache) {
1325 cache->pinned -= len;
1326 cache->space_info->bytes_pinned -= len;
1327 }
1328 fs_info->total_pinned -= len;
1329 }
1330 bytenr += len;
1331 num -= len;
1332 }
1333 return 0;
1334 }
1335
1336 int btrfs_copy_pinned(struct btrfs_root *root, struct extent_io_tree *copy)
1337 {
1338 u64 last = 0;
1339 u64 start;
1340 u64 end;
1341 struct extent_io_tree *pinned_extents = &root->fs_info->pinned_extents;
1342 int ret;
1343
1344 while(1) {
1345 ret = find_first_extent_bit(pinned_extents, last,
1346 &start, &end, EXTENT_DIRTY);
1347 if (ret)
1348 break;
1349 set_extent_dirty(copy, start, end, GFP_NOFS);
1350 last = end + 1;
1351 }
1352 return 0;
1353 }
1354
1355 int btrfs_finish_extent_commit(struct btrfs_trans_handle *trans,
1356 struct btrfs_root *root,
1357 struct extent_io_tree *unpin)
1358 {
1359 u64 start;
1360 u64 end;
1361 int ret;
1362 struct extent_io_tree *free_space_cache;
1363 free_space_cache = &root->fs_info->free_space_cache;
1364
1365 mutex_lock(&root->fs_info->alloc_mutex);
1366 while(1) {
1367 ret = find_first_extent_bit(unpin, 0, &start, &end,
1368 EXTENT_DIRTY);
1369 if (ret)
1370 break;
1371 update_pinned_extents(root, start, end + 1 - start, 0);
1372 clear_extent_dirty(unpin, start, end, GFP_NOFS);
1373 set_extent_dirty(free_space_cache, start, end, GFP_NOFS);
1374 }
1375 mutex_unlock(&root->fs_info->alloc_mutex);
1376 return 0;
1377 }
1378
1379 static int finish_current_insert(struct btrfs_trans_handle *trans,
1380 struct btrfs_root *extent_root)
1381 {
1382 u64 start;
1383 u64 end;
1384 struct btrfs_fs_info *info = extent_root->fs_info;
1385 struct extent_buffer *eb;
1386 struct btrfs_path *path;
1387 struct btrfs_key ins;
1388 struct btrfs_disk_key first;
1389 struct btrfs_extent_item extent_item;
1390 int ret;
1391 int level;
1392 int err = 0;
1393
1394 btrfs_set_stack_extent_refs(&extent_item, 1);
1395 btrfs_set_key_type(&ins, BTRFS_EXTENT_ITEM_KEY);
1396 path = btrfs_alloc_path();
1397
1398 while(1) {
1399 ret = find_first_extent_bit(&info->extent_ins, 0, &start,
1400 &end, EXTENT_LOCKED);
1401 if (ret)
1402 break;
1403
1404 ins.objectid = start;
1405 ins.offset = end + 1 - start;
1406 err = btrfs_insert_item(trans, extent_root, &ins,
1407 &extent_item, sizeof(extent_item));
1408 clear_extent_bits(&info->extent_ins, start, end, EXTENT_LOCKED,
1409 GFP_NOFS);
1410 eb = read_tree_block(extent_root, ins.objectid, ins.offset,
1411 trans->transid);
1412 btrfs_tree_lock(eb);
1413 level = btrfs_header_level(eb);
1414 if (level == 0) {
1415 btrfs_item_key(eb, &first, 0);
1416 } else {
1417 btrfs_node_key(eb, &first, 0);
1418 }
1419 btrfs_tree_unlock(eb);
1420 free_extent_buffer(eb);
1421 /*
1422 * the first key is just a hint, so the race we've created
1423 * against reading it is fine
1424 */
1425 err = btrfs_insert_extent_backref(trans, extent_root, path,
1426 start, extent_root->root_key.objectid,
1427 0, level,
1428 btrfs_disk_key_objectid(&first));
1429 BUG_ON(err);
1430 }
1431 btrfs_free_path(path);
1432 return 0;
1433 }
1434
1435 static int pin_down_bytes(struct btrfs_root *root, u64 bytenr, u32 num_bytes,
1436 int pending)
1437 {
1438 int err = 0;
1439
1440 if (!pending) {
1441 struct extent_buffer *buf;
1442 buf = btrfs_find_tree_block(root, bytenr, num_bytes);
1443 if (buf) {
1444 if (!btrfs_try_tree_lock(buf) &&
1445 btrfs_buffer_uptodate(buf, 0)) {
1446 u64 transid =
1447 root->fs_info->running_transaction->transid;
1448 u64 header_transid =
1449 btrfs_header_generation(buf);
1450 if (header_transid == transid &&
1451 !btrfs_header_flag(buf,
1452 BTRFS_HEADER_FLAG_WRITTEN)) {
1453 clean_tree_block(NULL, root, buf);
1454 btrfs_tree_unlock(buf);
1455 free_extent_buffer(buf);
1456 return 1;
1457 }
1458 btrfs_tree_unlock(buf);
1459 }
1460 free_extent_buffer(buf);
1461 }
1462 update_pinned_extents(root, bytenr, num_bytes, 1);
1463 } else {
1464 set_extent_bits(&root->fs_info->pending_del,
1465 bytenr, bytenr + num_bytes - 1,
1466 EXTENT_LOCKED, GFP_NOFS);
1467 }
1468 BUG_ON(err < 0);
1469 return 0;
1470 }
1471
1472 /*
1473 * remove an extent from the root, returns 0 on success
1474 */
1475 static int __free_extent(struct btrfs_trans_handle *trans, struct btrfs_root
1476 *root, u64 bytenr, u64 num_bytes,
1477 u64 root_objectid, u64 ref_generation,
1478 u64 owner_objectid, u64 owner_offset, int pin,
1479 int mark_free)
1480 {
1481 struct btrfs_path *path;
1482 struct btrfs_key key;
1483 struct btrfs_fs_info *info = root->fs_info;
1484 struct btrfs_root *extent_root = info->extent_root;
1485 struct extent_buffer *leaf;
1486 int ret;
1487 int extent_slot = 0;
1488 int found_extent = 0;
1489 int num_to_del = 1;
1490 struct btrfs_extent_item *ei;
1491 u32 refs;
1492
1493 key.objectid = bytenr;
1494 btrfs_set_key_type(&key, BTRFS_EXTENT_ITEM_KEY);
1495 key.offset = num_bytes;
1496 path = btrfs_alloc_path();
1497 if (!path)
1498 return -ENOMEM;
1499
1500 path->reada = 1;
1501 ret = lookup_extent_backref(trans, extent_root, path,
1502 bytenr, root_objectid,
1503 ref_generation,
1504 owner_objectid, owner_offset, 1);
1505 if (ret == 0) {
1506 struct btrfs_key found_key;
1507 extent_slot = path->slots[0];
1508 while(extent_slot > 0) {
1509 extent_slot--;
1510 btrfs_item_key_to_cpu(path->nodes[0], &found_key,
1511 extent_slot);
1512 if (found_key.objectid != bytenr)
1513 break;
1514 if (found_key.type == BTRFS_EXTENT_ITEM_KEY &&
1515 found_key.offset == num_bytes) {
1516 found_extent = 1;
1517 break;
1518 }
1519 if (path->slots[0] - extent_slot > 5)
1520 break;
1521 }
1522 if (!found_extent)
1523 ret = btrfs_del_item(trans, extent_root, path);
1524 } else {
1525 btrfs_print_leaf(extent_root, path->nodes[0]);
1526 WARN_ON(1);
1527 printk("Unable to find ref byte nr %Lu root %Lu "
1528 " gen %Lu owner %Lu offset %Lu\n", bytenr,
1529 root_objectid, ref_generation, owner_objectid,
1530 owner_offset);
1531 }
1532 if (!found_extent) {
1533 btrfs_release_path(extent_root, path);
1534 ret = btrfs_search_slot(trans, extent_root, &key, path, -1, 1);
1535 if (ret < 0)
1536 return ret;
1537 BUG_ON(ret);
1538 extent_slot = path->slots[0];
1539 }
1540
1541 leaf = path->nodes[0];
1542 ei = btrfs_item_ptr(leaf, extent_slot,
1543 struct btrfs_extent_item);
1544 refs = btrfs_extent_refs(leaf, ei);
1545 BUG_ON(refs == 0);
1546 refs -= 1;
1547 btrfs_set_extent_refs(leaf, ei, refs);
1548
1549 btrfs_mark_buffer_dirty(leaf);
1550
1551 if (refs == 0 && found_extent && path->slots[0] == extent_slot + 1) {
1552 /* if the back ref and the extent are next to each other
1553 * they get deleted below in one shot
1554 */
1555 path->slots[0] = extent_slot;
1556 num_to_del = 2;
1557 } else if (found_extent) {
1558 /* otherwise delete the extent back ref */
1559 ret = btrfs_del_item(trans, extent_root, path);
1560 BUG_ON(ret);
1561 /* if refs are 0, we need to setup the path for deletion */
1562 if (refs == 0) {
1563 btrfs_release_path(extent_root, path);
1564 ret = btrfs_search_slot(trans, extent_root, &key, path,
1565 -1, 1);
1566 if (ret < 0)
1567 return ret;
1568 BUG_ON(ret);
1569 }
1570 }
1571
1572 if (refs == 0) {
1573 u64 super_used;
1574 u64 root_used;
1575
1576 if (pin) {
1577 ret = pin_down_bytes(root, bytenr, num_bytes, 0);
1578 if (ret > 0)
1579 mark_free = 1;
1580 BUG_ON(ret < 0);
1581 }
1582
1583 /* block accounting for super block */
1584 spin_lock_irq(&info->delalloc_lock);
1585 super_used = btrfs_super_bytes_used(&info->super_copy);
1586 btrfs_set_super_bytes_used(&info->super_copy,
1587 super_used - num_bytes);
1588 spin_unlock_irq(&info->delalloc_lock);
1589
1590 /* block accounting for root item */
1591 root_used = btrfs_root_used(&root->root_item);
1592 btrfs_set_root_used(&root->root_item,
1593 root_used - num_bytes);
1594 ret = btrfs_del_items(trans, extent_root, path, path->slots[0],
1595 num_to_del);
1596 if (ret) {
1597 return ret;
1598 }
1599 ret = update_block_group(trans, root, bytenr, num_bytes, 0,
1600 mark_free);
1601 BUG_ON(ret);
1602 }
1603 btrfs_free_path(path);
1604 finish_current_insert(trans, extent_root);
1605 return ret;
1606 }
1607
1608 /*
1609 * find all the blocks marked as pending in the radix tree and remove
1610 * them from the extent map
1611 */
1612 static int del_pending_extents(struct btrfs_trans_handle *trans, struct
1613 btrfs_root *extent_root)
1614 {
1615 int ret;
1616 int err = 0;
1617 u64 start;
1618 u64 end;
1619 struct extent_io_tree *pending_del;
1620 struct extent_io_tree *pinned_extents;
1621
1622 pending_del = &extent_root->fs_info->pending_del;
1623 pinned_extents = &extent_root->fs_info->pinned_extents;
1624
1625 while(1) {
1626 ret = find_first_extent_bit(pending_del, 0, &start, &end,
1627 EXTENT_LOCKED);
1628 if (ret)
1629 break;
1630 update_pinned_extents(extent_root, start, end + 1 - start, 1);
1631 clear_extent_bits(pending_del, start, end, EXTENT_LOCKED,
1632 GFP_NOFS);
1633 ret = __free_extent(trans, extent_root,
1634 start, end + 1 - start,
1635 extent_root->root_key.objectid,
1636 0, 0, 0, 0, 0);
1637 if (ret)
1638 err = ret;
1639 }
1640 return err;
1641 }
1642
1643 /*
1644 * remove an extent from the root, returns 0 on success
1645 */
1646 static int __btrfs_free_extent(struct btrfs_trans_handle *trans,
1647 struct btrfs_root *root, u64 bytenr,
1648 u64 num_bytes, u64 root_objectid,
1649 u64 ref_generation, u64 owner_objectid,
1650 u64 owner_offset, int pin)
1651 {
1652 struct btrfs_root *extent_root = root->fs_info->extent_root;
1653 int pending_ret;
1654 int ret;
1655
1656 WARN_ON(num_bytes < root->sectorsize);
1657 if (!root->ref_cows)
1658 ref_generation = 0;
1659
1660 if (root == extent_root) {
1661 pin_down_bytes(root, bytenr, num_bytes, 1);
1662 return 0;
1663 }
1664 ret = __free_extent(trans, root, bytenr, num_bytes, root_objectid,
1665 ref_generation, owner_objectid, owner_offset,
1666 pin, pin == 0);
1667 pending_ret = del_pending_extents(trans, root->fs_info->extent_root);
1668 return ret ? ret : pending_ret;
1669 }
1670
1671 int btrfs_free_extent(struct btrfs_trans_handle *trans,
1672 struct btrfs_root *root, u64 bytenr,
1673 u64 num_bytes, u64 root_objectid,
1674 u64 ref_generation, u64 owner_objectid,
1675 u64 owner_offset, int pin)
1676 {
1677 int ret;
1678
1679 maybe_lock_mutex(root);
1680 ret = __btrfs_free_extent(trans, root, bytenr, num_bytes,
1681 root_objectid, ref_generation,
1682 owner_objectid, owner_offset, pin);
1683 maybe_unlock_mutex(root);
1684 return ret;
1685 }
1686
1687 static u64 stripe_align(struct btrfs_root *root, u64 val)
1688 {
1689 u64 mask = ((u64)root->stripesize - 1);
1690 u64 ret = (val + mask) & ~mask;
1691 return ret;
1692 }
1693
1694 /*
1695 * walks the btree of allocated extents and find a hole of a given size.
1696 * The key ins is changed to record the hole:
1697 * ins->objectid == block start
1698 * ins->flags = BTRFS_EXTENT_ITEM_KEY
1699 * ins->offset == number of blocks
1700 * Any available blocks before search_start are skipped.
1701 */
1702 static int noinline find_free_extent(struct btrfs_trans_handle *trans,
1703 struct btrfs_root *orig_root,
1704 u64 num_bytes, u64 empty_size,
1705 u64 search_start, u64 search_end,
1706 u64 hint_byte, struct btrfs_key *ins,
1707 u64 exclude_start, u64 exclude_nr,
1708 int data)
1709 {
1710 int ret;
1711 u64 orig_search_start;
1712 struct btrfs_root * root = orig_root->fs_info->extent_root;
1713 struct btrfs_fs_info *info = root->fs_info;
1714 u64 total_needed = num_bytes;
1715 u64 *last_ptr = NULL;
1716 struct btrfs_block_group_cache *block_group;
1717 int full_scan = 0;
1718 int wrapped = 0;
1719 int chunk_alloc_done = 0;
1720 int empty_cluster = 2 * 1024 * 1024;
1721 int allowed_chunk_alloc = 0;
1722
1723 WARN_ON(num_bytes < root->sectorsize);
1724 btrfs_set_key_type(ins, BTRFS_EXTENT_ITEM_KEY);
1725
1726 if (orig_root->ref_cows || empty_size)
1727 allowed_chunk_alloc = 1;
1728
1729 if (data & BTRFS_BLOCK_GROUP_METADATA) {
1730 last_ptr = &root->fs_info->last_alloc;
1731 empty_cluster = 256 * 1024;
1732 }
1733
1734 if ((data & BTRFS_BLOCK_GROUP_DATA) && btrfs_test_opt(root, SSD)) {
1735 last_ptr = &root->fs_info->last_data_alloc;
1736 }
1737
1738 if (last_ptr) {
1739 if (*last_ptr)
1740 hint_byte = *last_ptr;
1741 else {
1742 empty_size += empty_cluster;
1743 }
1744 }
1745
1746 search_start = max(search_start, first_logical_byte(root, 0));
1747 orig_search_start = search_start;
1748
1749 if (search_end == (u64)-1)
1750 search_end = btrfs_super_total_bytes(&info->super_copy);
1751
1752 if (hint_byte) {
1753 block_group = btrfs_lookup_first_block_group(info, hint_byte);
1754 if (!block_group)
1755 hint_byte = search_start;
1756 block_group = __btrfs_find_block_group(root, block_group,
1757 hint_byte, data, 1);
1758 if (last_ptr && *last_ptr == 0 && block_group)
1759 hint_byte = block_group->key.objectid;
1760 } else {
1761 block_group = __btrfs_find_block_group(root,
1762 trans->block_group,
1763 search_start, data, 1);
1764 }
1765 search_start = max(search_start, hint_byte);
1766
1767 total_needed += empty_size;
1768
1769 check_failed:
1770 if (!block_group) {
1771 block_group = btrfs_lookup_first_block_group(info,
1772 search_start);
1773 if (!block_group)
1774 block_group = btrfs_lookup_first_block_group(info,
1775 orig_search_start);
1776 }
1777 if (full_scan && !chunk_alloc_done) {
1778 if (allowed_chunk_alloc) {
1779 do_chunk_alloc(trans, root,
1780 num_bytes + 2 * 1024 * 1024, data, 1);
1781 allowed_chunk_alloc = 0;
1782 } else if (block_group && block_group_bits(block_group, data)) {
1783 block_group->space_info->force_alloc = 1;
1784 }
1785 chunk_alloc_done = 1;
1786 }
1787 ret = find_search_start(root, &block_group, &search_start,
1788 total_needed, data);
1789 if (ret == -ENOSPC && last_ptr && *last_ptr) {
1790 *last_ptr = 0;
1791 block_group = btrfs_lookup_first_block_group(info,
1792 orig_search_start);
1793 search_start = orig_search_start;
1794 ret = find_search_start(root, &block_group, &search_start,
1795 total_needed, data);
1796 }
1797 if (ret == -ENOSPC)
1798 goto enospc;
1799 if (ret)
1800 goto error;
1801
1802 if (last_ptr && *last_ptr && search_start != *last_ptr) {
1803 *last_ptr = 0;
1804 if (!empty_size) {
1805 empty_size += empty_cluster;
1806 total_needed += empty_size;
1807 }
1808 block_group = btrfs_lookup_first_block_group(info,
1809 orig_search_start);
1810 search_start = orig_search_start;
1811 ret = find_search_start(root, &block_group,
1812 &search_start, total_needed, data);
1813 if (ret == -ENOSPC)
1814 goto enospc;
1815 if (ret)
1816 goto error;
1817 }
1818
1819 search_start = stripe_align(root, search_start);
1820 ins->objectid = search_start;
1821 ins->offset = num_bytes;
1822
1823 if (ins->objectid + num_bytes >= search_end)
1824 goto enospc;
1825
1826 if (ins->objectid + num_bytes >
1827 block_group->key.objectid + block_group->key.offset) {
1828 search_start = block_group->key.objectid +
1829 block_group->key.offset;
1830 goto new_group;
1831 }
1832
1833 if (test_range_bit(&info->extent_ins, ins->objectid,
1834 ins->objectid + num_bytes -1, EXTENT_LOCKED, 0)) {
1835 search_start = ins->objectid + num_bytes;
1836 goto new_group;
1837 }
1838
1839 if (test_range_bit(&info->pinned_extents, ins->objectid,
1840 ins->objectid + num_bytes -1, EXTENT_DIRTY, 0)) {
1841 search_start = ins->objectid + num_bytes;
1842 goto new_group;
1843 }
1844
1845 if (exclude_nr > 0 && (ins->objectid + num_bytes > exclude_start &&
1846 ins->objectid < exclude_start + exclude_nr)) {
1847 search_start = exclude_start + exclude_nr;
1848 goto new_group;
1849 }
1850
1851 if (!(data & BTRFS_BLOCK_GROUP_DATA)) {
1852 block_group = btrfs_lookup_block_group(info, ins->objectid);
1853 if (block_group)
1854 trans->block_group = block_group;
1855 }
1856 ins->offset = num_bytes;
1857 if (last_ptr) {
1858 *last_ptr = ins->objectid + ins->offset;
1859 if (*last_ptr ==
1860 btrfs_super_total_bytes(&root->fs_info->super_copy)) {
1861 *last_ptr = 0;
1862 }
1863 }
1864 return 0;
1865
1866 new_group:
1867 if (search_start + num_bytes >= search_end) {
1868 enospc:
1869 search_start = orig_search_start;
1870 if (full_scan) {
1871 ret = -ENOSPC;
1872 goto error;
1873 }
1874 if (wrapped) {
1875 if (!full_scan)
1876 total_needed -= empty_size;
1877 full_scan = 1;
1878 } else
1879 wrapped = 1;
1880 }
1881 block_group = btrfs_lookup_first_block_group(info, search_start);
1882 cond_resched();
1883 block_group = __btrfs_find_block_group(root, block_group,
1884 search_start, data, 0);
1885 goto check_failed;
1886
1887 error:
1888 return ret;
1889 }
1890
1891 /*
1892 * finds a free extent and does all the dirty work required for allocation
1893 * returns the key for the extent through ins, and a tree buffer for
1894 * the first block of the extent through buf.
1895 *
1896 * returns 0 if everything worked, non-zero otherwise.
1897 */
1898 int btrfs_alloc_extent(struct btrfs_trans_handle *trans,
1899 struct btrfs_root *root,
1900 u64 num_bytes, u64 min_alloc_size,
1901 u64 root_objectid, u64 ref_generation,
1902 u64 owner, u64 owner_offset,
1903 u64 empty_size, u64 hint_byte,
1904 u64 search_end, struct btrfs_key *ins, u64 data)
1905 {
1906 int ret;
1907 int pending_ret;
1908 u64 super_used;
1909 u64 root_used;
1910 u64 search_start = 0;
1911 u64 alloc_profile;
1912 u32 sizes[2];
1913 struct btrfs_fs_info *info = root->fs_info;
1914 struct btrfs_root *extent_root = info->extent_root;
1915 struct btrfs_extent_item *extent_item;
1916 struct btrfs_extent_ref *ref;
1917 struct btrfs_path *path;
1918 struct btrfs_key keys[2];
1919
1920 maybe_lock_mutex(root);
1921
1922 if (data) {
1923 alloc_profile = info->avail_data_alloc_bits &
1924 info->data_alloc_profile;
1925 data = BTRFS_BLOCK_GROUP_DATA | alloc_profile;
1926 } else if (root == root->fs_info->chunk_root) {
1927 alloc_profile = info->avail_system_alloc_bits &
1928 info->system_alloc_profile;
1929 data = BTRFS_BLOCK_GROUP_SYSTEM | alloc_profile;
1930 } else {
1931 alloc_profile = info->avail_metadata_alloc_bits &
1932 info->metadata_alloc_profile;
1933 data = BTRFS_BLOCK_GROUP_METADATA | alloc_profile;
1934 }
1935 again:
1936 data = reduce_alloc_profile(root, data);
1937 /*
1938 * the only place that sets empty_size is btrfs_realloc_node, which
1939 * is not called recursively on allocations
1940 */
1941 if (empty_size || root->ref_cows) {
1942 if (!(data & BTRFS_BLOCK_GROUP_METADATA)) {
1943 ret = do_chunk_alloc(trans, root->fs_info->extent_root,
1944 2 * 1024 * 1024,
1945 BTRFS_BLOCK_GROUP_METADATA |
1946 (info->metadata_alloc_profile &
1947 info->avail_metadata_alloc_bits), 0);
1948 BUG_ON(ret);
1949 }
1950 ret = do_chunk_alloc(trans, root->fs_info->extent_root,
1951 num_bytes + 2 * 1024 * 1024, data, 0);
1952 BUG_ON(ret);
1953 }
1954
1955 WARN_ON(num_bytes < root->sectorsize);
1956 ret = find_free_extent(trans, root, num_bytes, empty_size,
1957 search_start, search_end, hint_byte, ins,
1958 trans->alloc_exclude_start,
1959 trans->alloc_exclude_nr, data);
1960
1961 if (ret == -ENOSPC && num_bytes > min_alloc_size) {
1962 num_bytes = num_bytes >> 1;
1963 num_bytes = max(num_bytes, min_alloc_size);
1964 do_chunk_alloc(trans, root->fs_info->extent_root,
1965 num_bytes, data, 1);
1966 goto again;
1967 }
1968 if (ret) {
1969 printk("allocation failed flags %Lu\n", data);
1970 }
1971 if (ret) {
1972 BUG();
1973 goto out;
1974 }
1975
1976 /* block accounting for super block */
1977 spin_lock_irq(&info->delalloc_lock);
1978 super_used = btrfs_super_bytes_used(&info->super_copy);
1979 btrfs_set_super_bytes_used(&info->super_copy, super_used + num_bytes);
1980 spin_unlock_irq(&info->delalloc_lock);
1981
1982 /* block accounting for root item */
1983 root_used = btrfs_root_used(&root->root_item);
1984 btrfs_set_root_used(&root->root_item, root_used + num_bytes);
1985
1986 clear_extent_dirty(&root->fs_info->free_space_cache,
1987 ins->objectid, ins->objectid + ins->offset - 1,
1988 GFP_NOFS);
1989
1990 if (root == extent_root) {
1991 set_extent_bits(&root->fs_info->extent_ins, ins->objectid,
1992 ins->objectid + ins->offset - 1,
1993 EXTENT_LOCKED, GFP_NOFS);
1994 goto update_block;
1995 }
1996
1997 WARN_ON(trans->alloc_exclude_nr);
1998 trans->alloc_exclude_start = ins->objectid;
1999 trans->alloc_exclude_nr = ins->offset;
2000
2001 memcpy(&keys[0], ins, sizeof(*ins));
2002 keys[1].offset = hash_extent_ref(root_objectid, ref_generation,
2003 owner, owner_offset);
2004 keys[1].objectid = ins->objectid;
2005 keys[1].type = BTRFS_EXTENT_REF_KEY;
2006 sizes[0] = sizeof(*extent_item);
2007 sizes[1] = sizeof(*ref);
2008
2009 path = btrfs_alloc_path();
2010 BUG_ON(!path);
2011
2012 ret = btrfs_insert_empty_items(trans, extent_root, path, keys,
2013 sizes, 2);
2014
2015 BUG_ON(ret);
2016 extent_item = btrfs_item_ptr(path->nodes[0], path->slots[0],
2017 struct btrfs_extent_item);
2018 btrfs_set_extent_refs(path->nodes[0], extent_item, 1);
2019 ref = btrfs_item_ptr(path->nodes[0], path->slots[0] + 1,
2020 struct btrfs_extent_ref);
2021
2022 btrfs_set_ref_root(path->nodes[0], ref, root_objectid);
2023 btrfs_set_ref_generation(path->nodes[0], ref, ref_generation);
2024 btrfs_set_ref_objectid(path->nodes[0], ref, owner);
2025 btrfs_set_ref_offset(path->nodes[0], ref, owner_offset);
2026
2027 btrfs_mark_buffer_dirty(path->nodes[0]);
2028
2029 trans->alloc_exclude_start = 0;
2030 trans->alloc_exclude_nr = 0;
2031 btrfs_free_path(path);
2032 finish_current_insert(trans, extent_root);
2033 pending_ret = del_pending_extents(trans, extent_root);
2034
2035 if (ret)
2036 goto out;
2037 if (pending_ret) {
2038 ret = pending_ret;
2039 goto out;
2040 }
2041
2042 update_block:
2043 ret = update_block_group(trans, root, ins->objectid, ins->offset, 1, 0);
2044 if (ret) {
2045 printk("update block group failed for %Lu %Lu\n",
2046 ins->objectid, ins->offset);
2047 BUG();
2048 }
2049 out:
2050 maybe_unlock_mutex(root);
2051 return ret;
2052 }
2053 /*
2054 * helper function to allocate a block for a given tree
2055 * returns the tree buffer or NULL.
2056 */
2057 struct extent_buffer *btrfs_alloc_free_block(struct btrfs_trans_handle *trans,
2058 struct btrfs_root *root,
2059 u32 blocksize,
2060 u64 root_objectid,
2061 u64 ref_generation,
2062 u64 first_objectid,
2063 int level,
2064 u64 hint,
2065 u64 empty_size)
2066 {
2067 struct btrfs_key ins;
2068 int ret;
2069 struct extent_buffer *buf;
2070
2071 ret = btrfs_alloc_extent(trans, root, blocksize, blocksize,
2072 root_objectid, ref_generation,
2073 level, first_objectid, empty_size, hint,
2074 (u64)-1, &ins, 0);
2075 if (ret) {
2076 BUG_ON(ret > 0);
2077 return ERR_PTR(ret);
2078 }
2079 buf = btrfs_find_create_tree_block(root, ins.objectid, blocksize);
2080 if (!buf) {
2081 btrfs_free_extent(trans, root, ins.objectid, blocksize,
2082 root->root_key.objectid, ref_generation,
2083 0, 0, 0);
2084 return ERR_PTR(-ENOMEM);
2085 }
2086 btrfs_set_header_generation(buf, trans->transid);
2087 btrfs_tree_lock(buf);
2088 clean_tree_block(trans, root, buf);
2089 btrfs_set_buffer_uptodate(buf);
2090
2091 if (PageDirty(buf->first_page)) {
2092 printk("page %lu dirty\n", buf->first_page->index);
2093 WARN_ON(1);
2094 }
2095
2096 set_extent_dirty(&trans->transaction->dirty_pages, buf->start,
2097 buf->start + buf->len - 1, GFP_NOFS);
2098 trans->blocks_used++;
2099 return buf;
2100 }
2101
2102 static int noinline drop_leaf_ref(struct btrfs_trans_handle *trans,
2103 struct btrfs_root *root,
2104 struct extent_buffer *leaf)
2105 {
2106 u64 leaf_owner;
2107 u64 leaf_generation;
2108 struct btrfs_key key;
2109 struct btrfs_file_extent_item *fi;
2110 int i;
2111 int nritems;
2112 int ret;
2113
2114 BUG_ON(!btrfs_is_leaf(leaf));
2115 nritems = btrfs_header_nritems(leaf);
2116 leaf_owner = btrfs_header_owner(leaf);
2117 leaf_generation = btrfs_header_generation(leaf);
2118
2119 for (i = 0; i < nritems; i++) {
2120 u64 disk_bytenr;
2121
2122 btrfs_item_key_to_cpu(leaf, &key, i);
2123 if (btrfs_key_type(&key) != BTRFS_EXTENT_DATA_KEY)
2124 continue;
2125 fi = btrfs_item_ptr(leaf, i, struct btrfs_file_extent_item);
2126 if (btrfs_file_extent_type(leaf, fi) ==
2127 BTRFS_FILE_EXTENT_INLINE)
2128 continue;
2129 /*
2130 * FIXME make sure to insert a trans record that
2131 * repeats the snapshot del on crash
2132 */
2133 disk_bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
2134 if (disk_bytenr == 0)
2135 continue;
2136 ret = __btrfs_free_extent(trans, root, disk_bytenr,
2137 btrfs_file_extent_disk_num_bytes(leaf, fi),
2138 leaf_owner, leaf_generation,
2139 key.objectid, key.offset, 0);
2140 BUG_ON(ret);
2141 }
2142 return 0;
2143 }
2144
2145 static void noinline reada_walk_down(struct btrfs_root *root,
2146 struct extent_buffer *node,
2147 int slot)
2148 {
2149 u64 bytenr;
2150 u64 last = 0;
2151 u32 nritems;
2152 u32 refs;
2153 u32 blocksize;
2154 int ret;
2155 int i;
2156 int level;
2157 int skipped = 0;
2158
2159 nritems = btrfs_header_nritems(node);
2160 level = btrfs_header_level(node);
2161 if (level)
2162 return;
2163
2164 for (i = slot; i < nritems && skipped < 32; i++) {
2165 bytenr = btrfs_node_blockptr(node, i);
2166 if (last && ((bytenr > last && bytenr - last > 32 * 1024) ||
2167 (last > bytenr && last - bytenr > 32 * 1024))) {
2168 skipped++;
2169 continue;
2170 }
2171 blocksize = btrfs_level_size(root, level - 1);
2172 if (i != slot) {
2173 ret = lookup_extent_ref(NULL, root, bytenr,
2174 blocksize, &refs);
2175 BUG_ON(ret);
2176 if (refs != 1) {
2177 skipped++;
2178 continue;
2179 }
2180 }
2181 ret = readahead_tree_block(root, bytenr, blocksize,
2182 btrfs_node_ptr_generation(node, i));
2183 last = bytenr + blocksize;
2184 cond_resched();
2185 if (ret)
2186 break;
2187 }
2188 }
2189
2190 /*
2191 * we want to avoid as much random IO as we can with the alloc mutex
2192 * held, so drop the lock and do the lookup, then do it again with the
2193 * lock held.
2194 */
2195 int drop_snap_lookup_refcount(struct btrfs_root *root, u64 start, u64 len,
2196 u32 *refs)
2197 {
2198 mutex_unlock(&root->fs_info->alloc_mutex);
2199 lookup_extent_ref(NULL, root, start, len, refs);
2200 cond_resched();
2201 mutex_lock(&root->fs_info->alloc_mutex);
2202 return lookup_extent_ref(NULL, root, start, len, refs);
2203 }
2204
2205 /*
2206 * helper function for drop_snapshot, this walks down the tree dropping ref
2207 * counts as it goes.
2208 */
2209 static int noinline walk_down_tree(struct btrfs_trans_handle *trans,
2210 struct btrfs_root *root,
2211 struct btrfs_path *path, int *level)
2212 {
2213 u64 root_owner;
2214 u64 root_gen;
2215 u64 bytenr;
2216 u64 ptr_gen;
2217 struct extent_buffer *next;
2218 struct extent_buffer *cur;
2219 struct extent_buffer *parent;
2220 u32 blocksize;
2221 int ret;
2222 u32 refs;
2223
2224 mutex_lock(&root->fs_info->alloc_mutex);
2225
2226 WARN_ON(*level < 0);
2227 WARN_ON(*level >= BTRFS_MAX_LEVEL);
2228 ret = drop_snap_lookup_refcount(root, path->nodes[*level]->start,
2229 path->nodes[*level]->len, &refs);
2230 BUG_ON(ret);
2231 if (refs > 1)
2232 goto out;
2233
2234 /*
2235 * walk down to the last node level and free all the leaves
2236 */
2237 while(*level >= 0) {
2238 WARN_ON(*level < 0);
2239 WARN_ON(*level >= BTRFS_MAX_LEVEL);
2240 cur = path->nodes[*level];
2241
2242 if (btrfs_header_level(cur) != *level)
2243 WARN_ON(1);
2244
2245 if (path->slots[*level] >=
2246 btrfs_header_nritems(cur))
2247 break;
2248 if (*level == 0) {
2249 ret = drop_leaf_ref(trans, root, cur);
2250 BUG_ON(ret);
2251 break;
2252 }
2253 bytenr = btrfs_node_blockptr(cur, path->slots[*level]);
2254 ptr_gen = btrfs_node_ptr_generation(cur, path->slots[*level]);
2255 blocksize = btrfs_level_size(root, *level - 1);
2256
2257 ret = drop_snap_lookup_refcount(root, bytenr, blocksize, &refs);
2258 BUG_ON(ret);
2259 if (refs != 1) {
2260 parent = path->nodes[*level];
2261 root_owner = btrfs_header_owner(parent);
2262 root_gen = btrfs_header_generation(parent);
2263 path->slots[*level]++;
2264 ret = __btrfs_free_extent(trans, root, bytenr,
2265 blocksize, root_owner,
2266 root_gen, 0, 0, 1);
2267 BUG_ON(ret);
2268 continue;
2269 }
2270 next = btrfs_find_tree_block(root, bytenr, blocksize);
2271 if (!next || !btrfs_buffer_uptodate(next, ptr_gen)) {
2272 free_extent_buffer(next);
2273 mutex_unlock(&root->fs_info->alloc_mutex);
2274
2275 if (path->slots[*level] == 0)
2276 reada_walk_down(root, cur, path->slots[*level]);
2277
2278 next = read_tree_block(root, bytenr, blocksize,
2279 ptr_gen);
2280 cond_resched();
2281 mutex_lock(&root->fs_info->alloc_mutex);
2282
2283 /* we've dropped the lock, double check */
2284 ret = drop_snap_lookup_refcount(root, bytenr,
2285 blocksize, &refs);
2286 BUG_ON(ret);
2287 if (refs != 1) {
2288 parent = path->nodes[*level];
2289 root_owner = btrfs_header_owner(parent);
2290 root_gen = btrfs_header_generation(parent);
2291
2292 path->slots[*level]++;
2293 free_extent_buffer(next);
2294 ret = __btrfs_free_extent(trans, root, bytenr,
2295 blocksize,
2296 root_owner,
2297 root_gen, 0, 0, 1);
2298 BUG_ON(ret);
2299 continue;
2300 }
2301 }
2302 WARN_ON(*level <= 0);
2303 if (path->nodes[*level-1])
2304 free_extent_buffer(path->nodes[*level-1]);
2305 path->nodes[*level-1] = next;
2306 *level = btrfs_header_level(next);
2307 path->slots[*level] = 0;
2308 }
2309 out:
2310 WARN_ON(*level < 0);
2311 WARN_ON(*level >= BTRFS_MAX_LEVEL);
2312
2313 if (path->nodes[*level] == root->node) {
2314 root_owner = root->root_key.objectid;
2315 parent = path->nodes[*level];
2316 } else {
2317 parent = path->nodes[*level + 1];
2318 root_owner = btrfs_header_owner(parent);
2319 }
2320
2321 root_gen = btrfs_header_generation(parent);
2322 ret = __btrfs_free_extent(trans, root, path->nodes[*level]->start,
2323 path->nodes[*level]->len,
2324 root_owner, root_gen, 0, 0, 1);
2325 free_extent_buffer(path->nodes[*level]);
2326 path->nodes[*level] = NULL;
2327 *level += 1;
2328 BUG_ON(ret);
2329 mutex_unlock(&root->fs_info->alloc_mutex);
2330 cond_resched();
2331 return 0;
2332 }
2333
2334 /*
2335 * helper for dropping snapshots. This walks back up the tree in the path
2336 * to find the first node higher up where we haven't yet gone through
2337 * all the slots
2338 */
2339 static int noinline walk_up_tree(struct btrfs_trans_handle *trans,
2340 struct btrfs_root *root,
2341 struct btrfs_path *path, int *level)
2342 {
2343 u64 root_owner;
2344 u64 root_gen;
2345 struct btrfs_root_item *root_item = &root->root_item;
2346 int i;
2347 int slot;
2348 int ret;
2349
2350 for(i = *level; i < BTRFS_MAX_LEVEL - 1 && path->nodes[i]; i++) {
2351 slot = path->slots[i];
2352 if (slot < btrfs_header_nritems(path->nodes[i]) - 1) {
2353 struct extent_buffer *node;
2354 struct btrfs_disk_key disk_key;
2355 node = path->nodes[i];
2356 path->slots[i]++;
2357 *level = i;
2358 WARN_ON(*level == 0);
2359 btrfs_node_key(node, &disk_key, path->slots[i]);
2360 memcpy(&root_item->drop_progress,
2361 &disk_key, sizeof(disk_key));
2362 root_item->drop_level = i;
2363 return 0;
2364 } else {
2365 if (path->nodes[*level] == root->node) {
2366 root_owner = root->root_key.objectid;
2367 root_gen =
2368 btrfs_header_generation(path->nodes[*level]);
2369 } else {
2370 struct extent_buffer *node;
2371 node = path->nodes[*level + 1];
2372 root_owner = btrfs_header_owner(node);
2373 root_gen = btrfs_header_generation(node);
2374 }
2375 ret = btrfs_free_extent(trans, root,
2376 path->nodes[*level]->start,
2377 path->nodes[*level]->len,
2378 root_owner, root_gen, 0, 0, 1);
2379 BUG_ON(ret);
2380 free_extent_buffer(path->nodes[*level]);
2381 path->nodes[*level] = NULL;
2382 *level = i + 1;
2383 }
2384 }
2385 return 1;
2386 }
2387
2388 /*
2389 * drop the reference count on the tree rooted at 'snap'. This traverses
2390 * the tree freeing any blocks that have a ref count of zero after being
2391 * decremented.
2392 */
2393 int btrfs_drop_snapshot(struct btrfs_trans_handle *trans, struct btrfs_root
2394 *root)
2395 {
2396 int ret = 0;
2397 int wret;
2398 int level;
2399 struct btrfs_path *path;
2400 int i;
2401 int orig_level;
2402 struct btrfs_root_item *root_item = &root->root_item;
2403
2404 WARN_ON(!mutex_is_locked(&root->fs_info->drop_mutex));
2405 path = btrfs_alloc_path();
2406 BUG_ON(!path);
2407
2408 level = btrfs_header_level(root->node);
2409 orig_level = level;
2410 if (btrfs_disk_key_objectid(&root_item->drop_progress) == 0) {
2411 path->nodes[level] = root->node;
2412 extent_buffer_get(root->node);
2413 path->slots[level] = 0;
2414 } else {
2415 struct btrfs_key key;
2416 struct btrfs_disk_key found_key;
2417 struct extent_buffer *node;
2418
2419 btrfs_disk_key_to_cpu(&key, &root_item->drop_progress);
2420 level = root_item->drop_level;
2421 path->lowest_level = level;
2422 wret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
2423 if (wret < 0) {
2424 ret = wret;
2425 goto out;
2426 }
2427 node = path->nodes[level];
2428 btrfs_node_key(node, &found_key, path->slots[level]);
2429 WARN_ON(memcmp(&found_key, &root_item->drop_progress,
2430 sizeof(found_key)));
2431 for (i = 0; i < BTRFS_MAX_LEVEL; i++) {
2432 if (path->nodes[i] && path->locks[i]) {
2433 path->locks[i] = 0;
2434 btrfs_tree_unlock(path->nodes[i]);
2435 }
2436 }
2437 }
2438 while(1) {
2439 wret = walk_down_tree(trans, root, path, &level);
2440 if (wret > 0)
2441 break;
2442 if (wret < 0)
2443 ret = wret;
2444
2445 wret = walk_up_tree(trans, root, path, &level);
2446 if (wret > 0)
2447 break;
2448 if (wret < 0)
2449 ret = wret;
2450 if (trans->transaction->in_commit) {
2451 ret = -EAGAIN;
2452 break;
2453 }
2454 }
2455 for (i = 0; i <= orig_level; i++) {
2456 if (path->nodes[i]) {
2457 free_extent_buffer(path->nodes[i]);
2458 path->nodes[i] = NULL;
2459 }
2460 }
2461 out:
2462 btrfs_free_path(path);
2463 return ret;
2464 }
2465
2466 int btrfs_free_block_groups(struct btrfs_fs_info *info)
2467 {
2468 u64 start;
2469 u64 end;
2470 u64 ptr;
2471 int ret;
2472
2473 mutex_lock(&info->alloc_mutex);
2474 while(1) {
2475 ret = find_first_extent_bit(&info->block_group_cache, 0,
2476 &start, &end, (unsigned int)-1);
2477 if (ret)
2478 break;
2479 ret = get_state_private(&info->block_group_cache, start, &ptr);
2480 if (!ret)
2481 kfree((void *)(unsigned long)ptr);
2482 clear_extent_bits(&info->block_group_cache, start,
2483 end, (unsigned int)-1, GFP_NOFS);
2484 }
2485 while(1) {
2486 ret = find_first_extent_bit(&info->free_space_cache, 0,
2487 &start, &end, EXTENT_DIRTY);
2488 if (ret)
2489 break;
2490 clear_extent_dirty(&info->free_space_cache, start,
2491 end, GFP_NOFS);
2492 }
2493 mutex_unlock(&info->alloc_mutex);
2494 return 0;
2495 }
2496
2497 static unsigned long calc_ra(unsigned long start, unsigned long last,
2498 unsigned long nr)
2499 {
2500 return min(last, start + nr - 1);
2501 }
2502
2503 static int noinline relocate_inode_pages(struct inode *inode, u64 start,
2504 u64 len)
2505 {
2506 u64 page_start;
2507 u64 page_end;
2508 unsigned long last_index;
2509 unsigned long i;
2510 struct page *page;
2511 struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
2512 struct file_ra_state *ra;
2513 unsigned long total_read = 0;
2514 unsigned long ra_pages;
2515 struct btrfs_trans_handle *trans;
2516
2517 ra = kzalloc(sizeof(*ra), GFP_NOFS);
2518
2519 mutex_lock(&inode->i_mutex);
2520 i = start >> PAGE_CACHE_SHIFT;
2521 last_index = (start + len - 1) >> PAGE_CACHE_SHIFT;
2522
2523 ra_pages = BTRFS_I(inode)->root->fs_info->bdi.ra_pages;
2524
2525 file_ra_state_init(ra, inode->i_mapping);
2526
2527 for (; i <= last_index; i++) {
2528 if (total_read % ra_pages == 0) {
2529 btrfs_force_ra(inode->i_mapping, ra, NULL, i,
2530 calc_ra(i, last_index, ra_pages));
2531 }
2532 total_read++;
2533 if (((u64)i << PAGE_CACHE_SHIFT) > inode->i_size)
2534 goto truncate_racing;
2535
2536 page = grab_cache_page(inode->i_mapping, i);
2537 if (!page) {
2538 goto out_unlock;
2539 }
2540 if (!PageUptodate(page)) {
2541 btrfs_readpage(NULL, page);
2542 lock_page(page);
2543 if (!PageUptodate(page)) {
2544 unlock_page(page);
2545 page_cache_release(page);
2546 goto out_unlock;
2547 }
2548 }
2549 #if LINUX_VERSION_CODE <= KERNEL_VERSION(2,6,18)
2550 ClearPageDirty(page);
2551 #else
2552 cancel_dirty_page(page, PAGE_CACHE_SIZE);
2553 #endif
2554 wait_on_page_writeback(page);
2555 set_page_extent_mapped(page);
2556 page_start = (u64)page->index << PAGE_CACHE_SHIFT;
2557 page_end = page_start + PAGE_CACHE_SIZE - 1;
2558
2559 lock_extent(io_tree, page_start, page_end, GFP_NOFS);
2560
2561 set_extent_delalloc(io_tree, page_start,
2562 page_end, GFP_NOFS);
2563 set_page_dirty(page);
2564
2565 unlock_extent(io_tree, page_start, page_end, GFP_NOFS);
2566 unlock_page(page);
2567 page_cache_release(page);
2568 }
2569 balance_dirty_pages_ratelimited_nr(inode->i_mapping,
2570 total_read);
2571
2572 out_unlock:
2573 kfree(ra);
2574 trans = btrfs_start_transaction(BTRFS_I(inode)->root, 1);
2575 if (trans) {
2576 btrfs_add_ordered_inode(inode);
2577 btrfs_end_transaction(trans, BTRFS_I(inode)->root);
2578 mark_inode_dirty(inode);
2579 }
2580 mutex_unlock(&inode->i_mutex);
2581 return 0;
2582
2583 truncate_racing:
2584 vmtruncate(inode, inode->i_size);
2585 balance_dirty_pages_ratelimited_nr(inode->i_mapping,
2586 total_read);
2587 goto out_unlock;
2588 }
2589
2590 /*
2591 * The back references tell us which tree holds a ref on a block,
2592 * but it is possible for the tree root field in the reference to
2593 * reflect the original root before a snapshot was made. In this
2594 * case we should search through all the children of a given root
2595 * to find potential holders of references on a block.
2596 *
2597 * Instead, we do something a little less fancy and just search
2598 * all the roots for a given key/block combination.
2599 */
2600 static int find_root_for_ref(struct btrfs_root *root,
2601 struct btrfs_path *path,
2602 struct btrfs_key *key0,
2603 int level,
2604 int file_key,
2605 struct btrfs_root **found_root,
2606 u64 bytenr)
2607 {
2608 struct btrfs_key root_location;
2609 struct btrfs_root *cur_root = *found_root;
2610 struct btrfs_file_extent_item *file_extent;
2611 u64 root_search_start = BTRFS_FS_TREE_OBJECTID;
2612 u64 found_bytenr;
2613 int ret;
2614 int i;
2615
2616 root_location.offset = (u64)-1;
2617 root_location.type = BTRFS_ROOT_ITEM_KEY;
2618 path->lowest_level = level;
2619 path->reada = 0;
2620 while(1) {
2621 ret = btrfs_search_slot(NULL, cur_root, key0, path, 0, 0);
2622 found_bytenr = 0;
2623 if (ret == 0 && file_key) {
2624 struct extent_buffer *leaf = path->nodes[0];
2625 file_extent = btrfs_item_ptr(leaf, path->slots[0],
2626 struct btrfs_file_extent_item);
2627 if (btrfs_file_extent_type(leaf, file_extent) ==
2628 BTRFS_FILE_EXTENT_REG) {
2629 found_bytenr =
2630 btrfs_file_extent_disk_bytenr(leaf,
2631 file_extent);
2632 }
2633 } else if (!file_key) {
2634 if (path->nodes[level])
2635 found_bytenr = path->nodes[level]->start;
2636 }
2637
2638 for (i = level; i < BTRFS_MAX_LEVEL; i++) {
2639 if (!path->nodes[i])
2640 break;
2641 free_extent_buffer(path->nodes[i]);
2642 path->nodes[i] = NULL;
2643 }
2644 btrfs_release_path(cur_root, path);
2645
2646 if (found_bytenr == bytenr) {
2647 *found_root = cur_root;
2648 ret = 0;
2649 goto out;
2650 }
2651 ret = btrfs_search_root(root->fs_info->tree_root,
2652 root_search_start, &root_search_start);
2653 if (ret)
2654 break;
2655
2656 root_location.objectid = root_search_start;
2657 cur_root = btrfs_read_fs_root_no_name(root->fs_info,
2658 &root_location);
2659 if (!cur_root) {
2660 ret = 1;
2661 break;
2662 }
2663 }
2664 out:
2665 path->lowest_level = 0;
2666 return ret;
2667 }
2668
2669 /*
2670 * note, this releases the path
2671 */
2672 static int noinline relocate_one_reference(struct btrfs_root *extent_root,
2673 struct btrfs_path *path,
2674 struct btrfs_key *extent_key,
2675 u64 *last_file_objectid,
2676 u64 *last_file_offset,
2677 u64 *last_file_root,
2678 u64 last_extent)
2679 {
2680 struct inode *inode;
2681 struct btrfs_root *found_root;
2682 struct btrfs_key root_location;
2683 struct btrfs_key found_key;
2684 struct btrfs_extent_ref *ref;
2685 u64 ref_root;
2686 u64 ref_gen;
2687 u64 ref_objectid;
2688 u64 ref_offset;
2689 int ret;
2690 int level;
2691
2692 ref = btrfs_item_ptr(path->nodes[0], path->slots[0],
2693 struct btrfs_extent_ref);
2694 ref_root = btrfs_ref_root(path->nodes[0], ref);
2695 ref_gen = btrfs_ref_generation(path->nodes[0], ref);
2696 ref_objectid = btrfs_ref_objectid(path->nodes[0], ref);
2697 ref_offset = btrfs_ref_offset(path->nodes[0], ref);
2698 btrfs_release_path(extent_root, path);
2699
2700 root_location.objectid = ref_root;
2701 if (ref_gen == 0)
2702 root_location.offset = 0;
2703 else
2704 root_location.offset = (u64)-1;
2705 root_location.type = BTRFS_ROOT_ITEM_KEY;
2706
2707 found_root = btrfs_read_fs_root_no_name(extent_root->fs_info,
2708 &root_location);
2709 BUG_ON(!found_root);
2710
2711 if (ref_objectid >= BTRFS_FIRST_FREE_OBJECTID) {
2712 found_key.objectid = ref_objectid;
2713 found_key.type = BTRFS_EXTENT_DATA_KEY;
2714 found_key.offset = ref_offset;
2715 level = 0;
2716
2717 if (last_extent == extent_key->objectid &&
2718 *last_file_objectid == ref_objectid &&
2719 *last_file_offset == ref_offset &&
2720 *last_file_root == ref_root)
2721 goto out;
2722
2723 ret = find_root_for_ref(extent_root, path, &found_key,
2724 level, 1, &found_root,
2725 extent_key->objectid);
2726
2727 if (ret)
2728 goto out;
2729
2730 if (last_extent == extent_key->objectid &&
2731 *last_file_objectid == ref_objectid &&
2732 *last_file_offset == ref_offset &&
2733 *last_file_root == ref_root)
2734 goto out;
2735
2736 inode = btrfs_iget_locked(extent_root->fs_info->sb,
2737 ref_objectid, found_root);
2738 if (inode->i_state & I_NEW) {
2739 /* the inode and parent dir are two different roots */
2740 BTRFS_I(inode)->root = found_root;
2741 BTRFS_I(inode)->location.objectid = ref_objectid;
2742 BTRFS_I(inode)->location.type = BTRFS_INODE_ITEM_KEY;
2743 BTRFS_I(inode)->location.offset = 0;
2744 btrfs_read_locked_inode(inode);
2745 unlock_new_inode(inode);
2746
2747 }
2748 /* this can happen if the reference is not against
2749 * the latest version of the tree root
2750 */
2751 if (is_bad_inode(inode)) {
2752 goto out;
2753 }
2754 *last_file_objectid = inode->i_ino;
2755 *last_file_root = found_root->root_key.objectid;
2756 *last_file_offset = ref_offset;
2757
2758 relocate_inode_pages(inode, ref_offset, extent_key->offset);
2759 iput(inode);
2760 } else {
2761 struct btrfs_trans_handle *trans;
2762 struct extent_buffer *eb;
2763 int i;
2764
2765 eb = read_tree_block(found_root, extent_key->objectid,
2766 extent_key->offset, 0);
2767 btrfs_tree_lock(eb);
2768 level = btrfs_header_level(eb);
2769
2770 if (level == 0)
2771 btrfs_item_key_to_cpu(eb, &found_key, 0);
2772 else
2773 btrfs_node_key_to_cpu(eb, &found_key, 0);
2774
2775 btrfs_tree_unlock(eb);
2776 free_extent_buffer(eb);
2777
2778 ret = find_root_for_ref(extent_root, path, &found_key,
2779 level, 0, &found_root,
2780 extent_key->objectid);
2781
2782 if (ret)
2783 goto out;
2784
2785 trans = btrfs_start_transaction(found_root, 1);
2786
2787 path->lowest_level = level;
2788 path->reada = 2;
2789 ret = btrfs_search_slot(trans, found_root, &found_key, path,
2790 0, 1);
2791 path->lowest_level = 0;
2792 for (i = level; i < BTRFS_MAX_LEVEL; i++) {
2793 if (!path->nodes[i])
2794 break;
2795 free_extent_buffer(path->nodes[i]);
2796 path->nodes[i] = NULL;
2797 }
2798 btrfs_release_path(found_root, path);
2799 if (found_root == found_root->fs_info->extent_root)
2800 btrfs_extent_post_op(trans, found_root);
2801 btrfs_end_transaction(trans, found_root);
2802 }
2803
2804 out:
2805 return 0;
2806 }
2807
2808 static int noinline del_extent_zero(struct btrfs_root *extent_root,
2809 struct btrfs_path *path,
2810 struct btrfs_key *extent_key)
2811 {
2812 int ret;
2813 struct btrfs_trans_handle *trans;
2814
2815 trans = btrfs_start_transaction(extent_root, 1);
2816 ret = btrfs_search_slot(trans, extent_root, extent_key, path, -1, 1);
2817 if (ret > 0) {
2818 ret = -EIO;
2819 goto out;
2820 }
2821 if (ret < 0)
2822 goto out;
2823 ret = btrfs_del_item(trans, extent_root, path);
2824 out:
2825 btrfs_end_transaction(trans, extent_root);
2826 return ret;
2827 }
2828
2829 static int noinline relocate_one_extent(struct btrfs_root *extent_root,
2830 struct btrfs_path *path,
2831 struct btrfs_key *extent_key)
2832 {
2833 struct btrfs_key key;
2834 struct btrfs_key found_key;
2835 struct extent_buffer *leaf;
2836 u64 last_file_objectid = 0;
2837 u64 last_file_root = 0;
2838 u64 last_file_offset = (u64)-1;
2839 u64 last_extent = 0;
2840 u32 nritems;
2841 u32 item_size;
2842 int ret = 0;
2843
2844 if (extent_key->objectid == 0) {
2845 ret = del_extent_zero(extent_root, path, extent_key);
2846 goto out;
2847 }
2848 key.objectid = extent_key->objectid;
2849 key.type = BTRFS_EXTENT_REF_KEY;
2850 key.offset = 0;
2851
2852 while(1) {
2853 ret = btrfs_search_slot(NULL, extent_root, &key, path, 0, 0);
2854
2855 if (ret < 0)
2856 goto out;
2857
2858 ret = 0;
2859 leaf = path->nodes[0];
2860 nritems = btrfs_header_nritems(leaf);
2861 if (path->slots[0] == nritems) {
2862 ret = btrfs_next_leaf(extent_root, path);
2863 if (ret > 0) {
2864 ret = 0;
2865 goto out;
2866 }
2867 if (ret < 0)
2868 goto out;
2869 leaf = path->nodes[0];
2870 }
2871
2872 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
2873 if (found_key.objectid != extent_key->objectid) {
2874 break;
2875 }
2876
2877 if (found_key.type != BTRFS_EXTENT_REF_KEY) {
2878 break;
2879 }
2880
2881 key.offset = found_key.offset + 1;
2882 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
2883
2884 ret = relocate_one_reference(extent_root, path, extent_key,
2885 &last_file_objectid,
2886 &last_file_offset,
2887 &last_file_root, last_extent);
2888 if (ret)
2889 goto out;
2890 last_extent = extent_key->objectid;
2891 }
2892 ret = 0;
2893 out:
2894 btrfs_release_path(extent_root, path);
2895 return ret;
2896 }
2897
2898 static u64 update_block_group_flags(struct btrfs_root *root, u64 flags)
2899 {
2900 u64 num_devices;
2901 u64 stripped = BTRFS_BLOCK_GROUP_RAID0 |
2902 BTRFS_BLOCK_GROUP_RAID1 | BTRFS_BLOCK_GROUP_RAID10;
2903
2904 num_devices = root->fs_info->fs_devices->num_devices;
2905 if (num_devices == 1) {
2906 stripped |= BTRFS_BLOCK_GROUP_DUP;
2907 stripped = flags & ~stripped;
2908
2909 /* turn raid0 into single device chunks */
2910 if (flags & BTRFS_BLOCK_GROUP_RAID0)
2911 return stripped;
2912
2913 /* turn mirroring into duplication */
2914 if (flags & (BTRFS_BLOCK_GROUP_RAID1 |
2915 BTRFS_BLOCK_GROUP_RAID10))
2916 return stripped | BTRFS_BLOCK_GROUP_DUP;
2917 return flags;
2918 } else {
2919 /* they already had raid on here, just return */
2920 if (flags & stripped)
2921 return flags;
2922
2923 stripped |= BTRFS_BLOCK_GROUP_DUP;
2924 stripped = flags & ~stripped;
2925
2926 /* switch duplicated blocks with raid1 */
2927 if (flags & BTRFS_BLOCK_GROUP_DUP)
2928 return stripped | BTRFS_BLOCK_GROUP_RAID1;
2929
2930 /* turn single device chunks into raid0 */
2931 return stripped | BTRFS_BLOCK_GROUP_RAID0;
2932 }
2933 return flags;
2934 }
2935
2936 int __alloc_chunk_for_shrink(struct btrfs_root *root,
2937 struct btrfs_block_group_cache *shrink_block_group,
2938 int force)
2939 {
2940 struct btrfs_trans_handle *trans;
2941 u64 new_alloc_flags;
2942 u64 calc;
2943
2944 if (btrfs_block_group_used(&shrink_block_group->item) > 0) {
2945
2946 trans = btrfs_start_transaction(root, 1);
2947 new_alloc_flags = update_block_group_flags(root,
2948 shrink_block_group->flags);
2949 if (new_alloc_flags != shrink_block_group->flags) {
2950 calc =
2951 btrfs_block_group_used(&shrink_block_group->item);
2952 } else {
2953 calc = shrink_block_group->key.offset;
2954 }
2955 do_chunk_alloc(trans, root->fs_info->extent_root,
2956 calc + 2 * 1024 * 1024, new_alloc_flags, force);
2957 btrfs_end_transaction(trans, root);
2958 }
2959 return 0;
2960 }
2961
2962 int btrfs_shrink_extent_tree(struct btrfs_root *root, u64 shrink_start)
2963 {
2964 struct btrfs_trans_handle *trans;
2965 struct btrfs_root *tree_root = root->fs_info->tree_root;
2966 struct btrfs_path *path;
2967 u64 cur_byte;
2968 u64 total_found;
2969 u64 shrink_last_byte;
2970 struct btrfs_block_group_cache *shrink_block_group;
2971 struct btrfs_fs_info *info = root->fs_info;
2972 struct btrfs_key key;
2973 struct btrfs_key found_key;
2974 struct extent_buffer *leaf;
2975 u32 nritems;
2976 int ret;
2977 int progress;
2978
2979 mutex_lock(&root->fs_info->alloc_mutex);
2980 shrink_block_group = btrfs_lookup_block_group(root->fs_info,
2981 shrink_start);
2982 BUG_ON(!shrink_block_group);
2983
2984 shrink_last_byte = shrink_block_group->key.objectid +
2985 shrink_block_group->key.offset;
2986
2987 shrink_block_group->space_info->total_bytes -=
2988 shrink_block_group->key.offset;
2989 path = btrfs_alloc_path();
2990 root = root->fs_info->extent_root;
2991 path->reada = 2;
2992
2993 printk("btrfs relocating block group %llu flags %llu\n",
2994 (unsigned long long)shrink_start,
2995 (unsigned long long)shrink_block_group->flags);
2996
2997 __alloc_chunk_for_shrink(root, shrink_block_group, 1);
2998
2999 again:
3000
3001 shrink_block_group->ro = 1;
3002
3003 total_found = 0;
3004 progress = 0;
3005 key.objectid = shrink_start;
3006 key.offset = 0;
3007 key.type = 0;
3008 cur_byte = key.objectid;
3009
3010 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
3011 if (ret < 0)
3012 goto out;
3013
3014 ret = btrfs_previous_item(root, path, 0, BTRFS_EXTENT_ITEM_KEY);
3015 if (ret < 0)
3016 goto out;
3017
3018 if (ret == 0) {
3019 leaf = path->nodes[0];
3020 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
3021 if (found_key.objectid + found_key.offset > shrink_start &&
3022 found_key.objectid < shrink_last_byte) {
3023 cur_byte = found_key.objectid;
3024 key.objectid = cur_byte;
3025 }
3026 }
3027 btrfs_release_path(root, path);
3028
3029 while(1) {
3030 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
3031 if (ret < 0)
3032 goto out;
3033
3034 leaf = path->nodes[0];
3035 nritems = btrfs_header_nritems(leaf);
3036 next:
3037 if (path->slots[0] >= nritems) {
3038 ret = btrfs_next_leaf(root, path);
3039 if (ret < 0)
3040 goto out;
3041 if (ret == 1) {
3042 ret = 0;
3043 break;
3044 }
3045 leaf = path->nodes[0];
3046 nritems = btrfs_header_nritems(leaf);
3047 }
3048
3049 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
3050
3051 if (found_key.objectid >= shrink_last_byte)
3052 break;
3053
3054 if (progress && need_resched()) {
3055 memcpy(&key, &found_key, sizeof(key));
3056 cond_resched();
3057 btrfs_release_path(root, path);
3058 btrfs_search_slot(NULL, root, &key, path, 0, 0);
3059 progress = 0;
3060 goto next;
3061 }
3062 progress = 1;
3063
3064 if (btrfs_key_type(&found_key) != BTRFS_EXTENT_ITEM_KEY ||
3065 found_key.objectid + found_key.offset <= cur_byte) {
3066 memcpy(&key, &found_key, sizeof(key));
3067 key.offset++;
3068 path->slots[0]++;
3069 goto next;
3070 }
3071
3072 total_found++;
3073 cur_byte = found_key.objectid + found_key.offset;
3074 key.objectid = cur_byte;
3075 btrfs_release_path(root, path);
3076 ret = relocate_one_extent(root, path, &found_key);
3077 __alloc_chunk_for_shrink(root, shrink_block_group, 0);
3078 }
3079
3080 btrfs_release_path(root, path);
3081
3082 if (total_found > 0) {
3083 printk("btrfs relocate found %llu last extent was %llu\n",
3084 (unsigned long long)total_found,
3085 (unsigned long long)found_key.objectid);
3086 trans = btrfs_start_transaction(tree_root, 1);
3087 btrfs_commit_transaction(trans, tree_root);
3088
3089 btrfs_clean_old_snapshots(tree_root);
3090
3091 trans = btrfs_start_transaction(tree_root, 1);
3092 btrfs_commit_transaction(trans, tree_root);
3093 goto again;
3094 }
3095
3096 /*
3097 * we've freed all the extents, now remove the block
3098 * group item from the tree
3099 */
3100 trans = btrfs_start_transaction(root, 1);
3101 memcpy(&key, &shrink_block_group->key, sizeof(key));
3102
3103 ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
3104 if (ret > 0)
3105 ret = -EIO;
3106 if (ret < 0)
3107 goto out;
3108
3109 clear_extent_bits(&info->block_group_cache, key.objectid,
3110 key.objectid + key.offset - 1,
3111 (unsigned int)-1, GFP_NOFS);
3112
3113
3114 clear_extent_bits(&info->free_space_cache,
3115 key.objectid, key.objectid + key.offset - 1,
3116 (unsigned int)-1, GFP_NOFS);
3117
3118 memset(shrink_block_group, 0, sizeof(*shrink_block_group));
3119 kfree(shrink_block_group);
3120
3121 btrfs_del_item(trans, root, path);
3122 btrfs_commit_transaction(trans, root);
3123
3124 /* the code to unpin extents might set a few bits in the free
3125 * space cache for this range again
3126 */
3127 clear_extent_bits(&info->free_space_cache,
3128 key.objectid, key.objectid + key.offset - 1,
3129 (unsigned int)-1, GFP_NOFS);
3130 out:
3131 btrfs_free_path(path);
3132 mutex_unlock(&root->fs_info->alloc_mutex);
3133 return ret;
3134 }
3135
3136 int find_first_block_group(struct btrfs_root *root, struct btrfs_path *path,
3137 struct btrfs_key *key)
3138 {
3139 int ret = 0;
3140 struct btrfs_key found_key;
3141 struct extent_buffer *leaf;
3142 int slot;
3143
3144 ret = btrfs_search_slot(NULL, root, key, path, 0, 0);
3145 if (ret < 0)
3146 goto out;
3147
3148 while(1) {
3149 slot = path->slots[0];
3150 leaf = path->nodes[0];
3151 if (slot >= btrfs_header_nritems(leaf)) {
3152 ret = btrfs_next_leaf(root, path);
3153 if (ret == 0)
3154 continue;
3155 if (ret < 0)
3156 goto out;
3157 break;
3158 }
3159 btrfs_item_key_to_cpu(leaf, &found_key, slot);
3160
3161 if (found_key.objectid >= key->objectid &&
3162 found_key.type == BTRFS_BLOCK_GROUP_ITEM_KEY) {
3163 ret = 0;
3164 goto out;
3165 }
3166 path->slots[0]++;
3167 }
3168 ret = -ENOENT;
3169 out:
3170 return ret;
3171 }
3172
3173 int btrfs_read_block_groups(struct btrfs_root *root)
3174 {
3175 struct btrfs_path *path;
3176 int ret;
3177 int bit;
3178 struct btrfs_block_group_cache *cache;
3179 struct btrfs_fs_info *info = root->fs_info;
3180 struct btrfs_space_info *space_info;
3181 struct extent_io_tree *block_group_cache;
3182 struct btrfs_key key;
3183 struct btrfs_key found_key;
3184 struct extent_buffer *leaf;
3185
3186 block_group_cache = &info->block_group_cache;
3187 root = info->extent_root;
3188 key.objectid = 0;
3189 key.offset = 0;
3190 btrfs_set_key_type(&key, BTRFS_BLOCK_GROUP_ITEM_KEY);
3191 path = btrfs_alloc_path();
3192 if (!path)
3193 return -ENOMEM;
3194
3195 mutex_lock(&root->fs_info->alloc_mutex);
3196 while(1) {
3197 ret = find_first_block_group(root, path, &key);
3198 if (ret > 0) {
3199 ret = 0;
3200 goto error;
3201 }
3202 if (ret != 0)
3203 goto error;
3204
3205 leaf = path->nodes[0];
3206 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
3207 cache = kzalloc(sizeof(*cache), GFP_NOFS);
3208 if (!cache) {
3209 ret = -ENOMEM;
3210 break;
3211 }
3212
3213 read_extent_buffer(leaf, &cache->item,
3214 btrfs_item_ptr_offset(leaf, path->slots[0]),
3215 sizeof(cache->item));
3216 memcpy(&cache->key, &found_key, sizeof(found_key));
3217
3218 key.objectid = found_key.objectid + found_key.offset;
3219 btrfs_release_path(root, path);
3220 cache->flags = btrfs_block_group_flags(&cache->item);
3221 bit = 0;
3222 if (cache->flags & BTRFS_BLOCK_GROUP_DATA) {
3223 bit = BLOCK_GROUP_DATA;
3224 } else if (cache->flags & BTRFS_BLOCK_GROUP_SYSTEM) {
3225 bit = BLOCK_GROUP_SYSTEM;
3226 } else if (cache->flags & BTRFS_BLOCK_GROUP_METADATA) {
3227 bit = BLOCK_GROUP_METADATA;
3228 }
3229 set_avail_alloc_bits(info, cache->flags);
3230
3231 ret = update_space_info(info, cache->flags, found_key.offset,
3232 btrfs_block_group_used(&cache->item),
3233 &space_info);
3234 BUG_ON(ret);
3235 cache->space_info = space_info;
3236
3237 /* use EXTENT_LOCKED to prevent merging */
3238 set_extent_bits(block_group_cache, found_key.objectid,
3239 found_key.objectid + found_key.offset - 1,
3240 bit | EXTENT_LOCKED, GFP_NOFS);
3241 set_state_private(block_group_cache, found_key.objectid,
3242 (unsigned long)cache);
3243
3244 if (key.objectid >=
3245 btrfs_super_total_bytes(&info->super_copy))
3246 break;
3247 }
3248 ret = 0;
3249 error:
3250 btrfs_free_path(path);
3251 mutex_unlock(&root->fs_info->alloc_mutex);
3252 return ret;
3253 }
3254
3255 int btrfs_make_block_group(struct btrfs_trans_handle *trans,
3256 struct btrfs_root *root, u64 bytes_used,
3257 u64 type, u64 chunk_objectid, u64 chunk_offset,
3258 u64 size)
3259 {
3260 int ret;
3261 int bit = 0;
3262 struct btrfs_root *extent_root;
3263 struct btrfs_block_group_cache *cache;
3264 struct extent_io_tree *block_group_cache;
3265
3266 extent_root = root->fs_info->extent_root;
3267 block_group_cache = &root->fs_info->block_group_cache;
3268
3269 cache = kzalloc(sizeof(*cache), GFP_NOFS);
3270 BUG_ON(!cache);
3271 cache->key.objectid = chunk_offset;
3272 cache->key.offset = size;
3273 btrfs_set_key_type(&cache->key, BTRFS_BLOCK_GROUP_ITEM_KEY);
3274
3275 btrfs_set_block_group_used(&cache->item, bytes_used);
3276 btrfs_set_block_group_chunk_objectid(&cache->item, chunk_objectid);
3277 cache->flags = type;
3278 btrfs_set_block_group_flags(&cache->item, type);
3279
3280 ret = update_space_info(root->fs_info, cache->flags, size, bytes_used,
3281 &cache->space_info);
3282 BUG_ON(ret);
3283
3284 bit = block_group_state_bits(type);
3285 set_extent_bits(block_group_cache, chunk_offset,
3286 chunk_offset + size - 1,
3287 bit | EXTENT_LOCKED, GFP_NOFS);
3288
3289 set_state_private(block_group_cache, chunk_offset,
3290 (unsigned long)cache);
3291 ret = btrfs_insert_item(trans, extent_root, &cache->key, &cache->item,
3292 sizeof(cache->item));
3293 BUG_ON(ret);
3294
3295 finish_current_insert(trans, extent_root);
3296 ret = del_pending_extents(trans, extent_root);
3297 BUG_ON(ret);
3298 set_avail_alloc_bits(extent_root->fs_info, type);
3299
3300 return 0;
3301 }
Linux kernel - Deliverables
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