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Btrfs: Allocator fix variety pack
[deliverable/linux.git] / fs / btrfs / extent-tree.c
1 /*
2 * Copyright (C) 2007 Oracle. All rights reserved.
3 *
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU General Public
6 * License v2 as published by the Free Software Foundation.
7 *
8 * This program is distributed in the hope that it will be useful,
9 * but WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
11 * General Public License for more details.
12 *
13 * You should have received a copy of the GNU General Public
14 * License along with this program; if not, write to the
15 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
16 * Boston, MA 021110-1307, USA.
17 */
18 #include <linux/sched.h>
19 #include <linux/pagemap.h>
20 #include <linux/writeback.h>
21 #include "hash.h"
22 #include "crc32c.h"
23 #include "ctree.h"
24 #include "disk-io.h"
25 #include "print-tree.h"
26 #include "transaction.h"
27 #include "volumes.h"
28
29 #define BLOCK_GROUP_DATA EXTENT_WRITEBACK
30 #define BLOCK_GROUP_METADATA EXTENT_UPTODATE
31 #define BLOCK_GROUP_SYSTEM EXTENT_NEW
32
33 #define BLOCK_GROUP_DIRTY EXTENT_DIRTY
34
35 static int finish_current_insert(struct btrfs_trans_handle *trans, struct
36 btrfs_root *extent_root);
37 static int del_pending_extents(struct btrfs_trans_handle *trans, struct
38 btrfs_root *extent_root);
39
40
41 static int cache_block_group(struct btrfs_root *root,
42 struct btrfs_block_group_cache *block_group)
43 {
44 struct btrfs_path *path;
45 int ret;
46 struct btrfs_key key;
47 struct extent_buffer *leaf;
48 struct extent_io_tree *free_space_cache;
49 int slot;
50 u64 last = 0;
51 u64 hole_size;
52 u64 first_free;
53 int found = 0;
54
55 if (!block_group)
56 return 0;
57
58 root = root->fs_info->extent_root;
59 free_space_cache = &root->fs_info->free_space_cache;
60
61 if (block_group->cached)
62 return 0;
63
64 path = btrfs_alloc_path();
65 if (!path)
66 return -ENOMEM;
67
68 path->reada = 2;
69 first_free = block_group->key.objectid;
70 key.objectid = block_group->key.objectid;
71 key.offset = 0;
72 btrfs_set_key_type(&key, BTRFS_EXTENT_ITEM_KEY);
73 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
74 if (ret < 0)
75 return ret;
76 ret = btrfs_previous_item(root, path, 0, BTRFS_EXTENT_ITEM_KEY);
77 if (ret < 0)
78 return ret;
79 if (ret == 0) {
80 leaf = path->nodes[0];
81 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
82 if (key.objectid + key.offset > first_free)
83 first_free = key.objectid + key.offset;
84 }
85 while(1) {
86 leaf = path->nodes[0];
87 slot = path->slots[0];
88 if (slot >= btrfs_header_nritems(leaf)) {
89 ret = btrfs_next_leaf(root, path);
90 if (ret < 0)
91 goto err;
92 if (ret == 0) {
93 continue;
94 } else {
95 break;
96 }
97 }
98 btrfs_item_key_to_cpu(leaf, &key, slot);
99 if (key.objectid < block_group->key.objectid) {
100 goto next;
101 }
102 if (key.objectid >= block_group->key.objectid +
103 block_group->key.offset) {
104 break;
105 }
106
107 if (btrfs_key_type(&key) == BTRFS_EXTENT_ITEM_KEY) {
108 if (!found) {
109 last = first_free;
110 found = 1;
111 }
112 if (key.objectid > last) {
113 hole_size = key.objectid - last;
114 set_extent_dirty(free_space_cache, last,
115 last + hole_size - 1,
116 GFP_NOFS);
117 }
118 last = key.objectid + key.offset;
119 }
120 next:
121 path->slots[0]++;
122 }
123
124 if (!found)
125 last = first_free;
126 if (block_group->key.objectid +
127 block_group->key.offset > last) {
128 hole_size = block_group->key.objectid +
129 block_group->key.offset - last;
130 set_extent_dirty(free_space_cache, last,
131 last + hole_size - 1, GFP_NOFS);
132 }
133 block_group->cached = 1;
134 err:
135 btrfs_free_path(path);
136 return 0;
137 }
138
139 struct btrfs_block_group_cache *btrfs_lookup_first_block_group(struct
140 btrfs_fs_info *info,
141 u64 bytenr)
142 {
143 struct extent_io_tree *block_group_cache;
144 struct btrfs_block_group_cache *block_group = NULL;
145 u64 ptr;
146 u64 start;
147 u64 end;
148 int ret;
149
150 bytenr = max_t(u64, bytenr,
151 BTRFS_SUPER_INFO_OFFSET + BTRFS_SUPER_INFO_SIZE);
152 block_group_cache = &info->block_group_cache;
153 ret = find_first_extent_bit(block_group_cache,
154 bytenr, &start, &end,
155 BLOCK_GROUP_DATA | BLOCK_GROUP_METADATA |
156 BLOCK_GROUP_SYSTEM);
157 if (ret) {
158 return NULL;
159 }
160 ret = get_state_private(block_group_cache, start, &ptr);
161 if (ret)
162 return NULL;
163
164 block_group = (struct btrfs_block_group_cache *)(unsigned long)ptr;
165 return block_group;
166 }
167
168 struct btrfs_block_group_cache *btrfs_lookup_block_group(struct
169 btrfs_fs_info *info,
170 u64 bytenr)
171 {
172 struct extent_io_tree *block_group_cache;
173 struct btrfs_block_group_cache *block_group = NULL;
174 u64 ptr;
175 u64 start;
176 u64 end;
177 int ret;
178
179 bytenr = max_t(u64, bytenr,
180 BTRFS_SUPER_INFO_OFFSET + BTRFS_SUPER_INFO_SIZE);
181 block_group_cache = &info->block_group_cache;
182 ret = find_first_extent_bit(block_group_cache,
183 bytenr, &start, &end,
184 BLOCK_GROUP_DATA | BLOCK_GROUP_METADATA |
185 BLOCK_GROUP_SYSTEM);
186 if (ret) {
187 return NULL;
188 }
189 ret = get_state_private(block_group_cache, start, &ptr);
190 if (ret)
191 return NULL;
192
193 block_group = (struct btrfs_block_group_cache *)(unsigned long)ptr;
194 if (block_group->key.objectid <= bytenr && bytenr <
195 block_group->key.objectid + block_group->key.offset)
196 return block_group;
197 return NULL;
198 }
199
200 static int block_group_bits(struct btrfs_block_group_cache *cache, u64 bits)
201 {
202 return (cache->flags & bits) == bits;
203 }
204
205 static int noinline find_search_start(struct btrfs_root *root,
206 struct btrfs_block_group_cache **cache_ret,
207 u64 *start_ret, u64 num, int data)
208 {
209 int ret;
210 struct btrfs_block_group_cache *cache = *cache_ret;
211 struct extent_io_tree *free_space_cache;
212 struct extent_state *state;
213 u64 last;
214 u64 start = 0;
215 u64 cache_miss = 0;
216 u64 total_fs_bytes;
217 u64 search_start = *start_ret;
218 int wrapped = 0;
219
220 total_fs_bytes = btrfs_super_total_bytes(&root->fs_info->super_copy);
221 free_space_cache = &root->fs_info->free_space_cache;
222
223 if (!cache)
224 goto out;
225
226 again:
227 ret = cache_block_group(root, cache);
228 if (ret) {
229 goto out;
230 }
231
232 last = max(search_start, cache->key.objectid);
233 if (!block_group_bits(cache, data) || cache->ro)
234 goto new_group;
235
236 spin_lock_irq(&free_space_cache->lock);
237 state = find_first_extent_bit_state(free_space_cache, last, EXTENT_DIRTY);
238 while(1) {
239 if (!state) {
240 if (!cache_miss)
241 cache_miss = last;
242 spin_unlock_irq(&free_space_cache->lock);
243 goto new_group;
244 }
245
246 start = max(last, state->start);
247 last = state->end + 1;
248 if (last - start < num) {
249 do {
250 state = extent_state_next(state);
251 } while(state && !(state->state & EXTENT_DIRTY));
252 continue;
253 }
254 spin_unlock_irq(&free_space_cache->lock);
255 if (cache->ro) {
256 goto new_group;
257 }
258 if (start + num > cache->key.objectid + cache->key.offset)
259 goto new_group;
260 if (!block_group_bits(cache, data)) {
261 printk("block group bits don't match %Lu %d\n", cache->flags, data);
262 }
263 *start_ret = start;
264 return 0;
265 }
266 out:
267 cache = btrfs_lookup_block_group(root->fs_info, search_start);
268 if (!cache) {
269 printk("Unable to find block group for %Lu\n", search_start);
270 WARN_ON(1);
271 }
272 return -ENOSPC;
273
274 new_group:
275 last = cache->key.objectid + cache->key.offset;
276 wrapped:
277 cache = btrfs_lookup_first_block_group(root->fs_info, last);
278 if (!cache || cache->key.objectid >= total_fs_bytes) {
279 no_cache:
280 if (!wrapped) {
281 wrapped = 1;
282 last = search_start;
283 goto wrapped;
284 }
285 goto out;
286 }
287 if (cache_miss && !cache->cached) {
288 cache_block_group(root, cache);
289 last = cache_miss;
290 cache = btrfs_lookup_first_block_group(root->fs_info, last);
291 }
292 cache_miss = 0;
293 cache = btrfs_find_block_group(root, cache, last, data, 0);
294 if (!cache)
295 goto no_cache;
296 *cache_ret = cache;
297 goto again;
298 }
299
300 static u64 div_factor(u64 num, int factor)
301 {
302 if (factor == 10)
303 return num;
304 num *= factor;
305 do_div(num, 10);
306 return num;
307 }
308
309 static int block_group_state_bits(u64 flags)
310 {
311 int bits = 0;
312 if (flags & BTRFS_BLOCK_GROUP_DATA)
313 bits |= BLOCK_GROUP_DATA;
314 if (flags & BTRFS_BLOCK_GROUP_METADATA)
315 bits |= BLOCK_GROUP_METADATA;
316 if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
317 bits |= BLOCK_GROUP_SYSTEM;
318 return bits;
319 }
320
321 struct btrfs_block_group_cache *btrfs_find_block_group(struct btrfs_root *root,
322 struct btrfs_block_group_cache
323 *hint, u64 search_start,
324 int data, int owner)
325 {
326 struct btrfs_block_group_cache *cache;
327 struct extent_io_tree *block_group_cache;
328 struct btrfs_block_group_cache *found_group = NULL;
329 struct btrfs_fs_info *info = root->fs_info;
330 u64 used;
331 u64 last = 0;
332 u64 start;
333 u64 end;
334 u64 free_check;
335 u64 ptr;
336 int bit;
337 int ret;
338 int full_search = 0;
339 int factor = 10;
340 int wrapped = 0;
341
342 block_group_cache = &info->block_group_cache;
343
344 if (data & BTRFS_BLOCK_GROUP_METADATA)
345 factor = 9;
346
347 bit = block_group_state_bits(data);
348
349 if (search_start) {
350 struct btrfs_block_group_cache *shint;
351 shint = btrfs_lookup_first_block_group(info, search_start);
352 if (shint && block_group_bits(shint, data) && !shint->ro) {
353 used = btrfs_block_group_used(&shint->item);
354 if (used + shint->pinned <
355 div_factor(shint->key.offset, factor)) {
356 return shint;
357 }
358 }
359 }
360 if (hint && !hint->ro && block_group_bits(hint, data)) {
361 used = btrfs_block_group_used(&hint->item);
362 if (used + hint->pinned <
363 div_factor(hint->key.offset, factor)) {
364 return hint;
365 }
366 last = hint->key.objectid + hint->key.offset;
367 } else {
368 if (hint)
369 last = max(hint->key.objectid, search_start);
370 else
371 last = search_start;
372 }
373 again:
374 while(1) {
375 ret = find_first_extent_bit(block_group_cache, last,
376 &start, &end, bit);
377 if (ret)
378 break;
379
380 ret = get_state_private(block_group_cache, start, &ptr);
381 if (ret) {
382 last = end + 1;
383 continue;
384 }
385
386 cache = (struct btrfs_block_group_cache *)(unsigned long)ptr;
387 last = cache->key.objectid + cache->key.offset;
388 used = btrfs_block_group_used(&cache->item);
389
390 if (!cache->ro && block_group_bits(cache, data)) {
391 free_check = div_factor(cache->key.offset, factor);
392 if (used + cache->pinned < free_check) {
393 found_group = cache;
394 goto found;
395 }
396 }
397 cond_resched();
398 }
399 if (!wrapped) {
400 last = search_start;
401 wrapped = 1;
402 goto again;
403 }
404 if (!full_search && factor < 10) {
405 last = search_start;
406 full_search = 1;
407 factor = 10;
408 goto again;
409 }
410 found:
411 return found_group;
412 }
413
414 static u64 hash_extent_ref(u64 root_objectid, u64 ref_generation,
415 u64 owner, u64 owner_offset)
416 {
417 u32 high_crc = ~(u32)0;
418 u32 low_crc = ~(u32)0;
419 __le64 lenum;
420 lenum = cpu_to_le64(root_objectid);
421 high_crc = btrfs_crc32c(high_crc, &lenum, sizeof(lenum));
422 lenum = cpu_to_le64(ref_generation);
423 low_crc = btrfs_crc32c(low_crc, &lenum, sizeof(lenum));
424 if (owner >= BTRFS_FIRST_FREE_OBJECTID) {
425 lenum = cpu_to_le64(owner);
426 low_crc = btrfs_crc32c(low_crc, &lenum, sizeof(lenum));
427 lenum = cpu_to_le64(owner_offset);
428 low_crc = btrfs_crc32c(low_crc, &lenum, sizeof(lenum));
429 }
430 return ((u64)high_crc << 32) | (u64)low_crc;
431 }
432
433 static int match_extent_ref(struct extent_buffer *leaf,
434 struct btrfs_extent_ref *disk_ref,
435 struct btrfs_extent_ref *cpu_ref)
436 {
437 int ret;
438 int len;
439
440 if (cpu_ref->objectid)
441 len = sizeof(*cpu_ref);
442 else
443 len = 2 * sizeof(u64);
444 ret = memcmp_extent_buffer(leaf, cpu_ref, (unsigned long)disk_ref,
445 len);
446 return ret == 0;
447 }
448
449 static int noinline lookup_extent_backref(struct btrfs_trans_handle *trans,
450 struct btrfs_root *root,
451 struct btrfs_path *path, u64 bytenr,
452 u64 root_objectid,
453 u64 ref_generation, u64 owner,
454 u64 owner_offset, int del)
455 {
456 u64 hash;
457 struct btrfs_key key;
458 struct btrfs_key found_key;
459 struct btrfs_extent_ref ref;
460 struct extent_buffer *leaf;
461 struct btrfs_extent_ref *disk_ref;
462 int ret;
463 int ret2;
464
465 btrfs_set_stack_ref_root(&ref, root_objectid);
466 btrfs_set_stack_ref_generation(&ref, ref_generation);
467 btrfs_set_stack_ref_objectid(&ref, owner);
468 btrfs_set_stack_ref_offset(&ref, owner_offset);
469
470 hash = hash_extent_ref(root_objectid, ref_generation, owner,
471 owner_offset);
472 key.offset = hash;
473 key.objectid = bytenr;
474 key.type = BTRFS_EXTENT_REF_KEY;
475
476 while (1) {
477 ret = btrfs_search_slot(trans, root, &key, path,
478 del ? -1 : 0, del);
479 if (ret < 0)
480 goto out;
481 leaf = path->nodes[0];
482 if (ret != 0) {
483 u32 nritems = btrfs_header_nritems(leaf);
484 if (path->slots[0] >= nritems) {
485 ret2 = btrfs_next_leaf(root, path);
486 if (ret2)
487 goto out;
488 leaf = path->nodes[0];
489 }
490 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
491 if (found_key.objectid != bytenr ||
492 found_key.type != BTRFS_EXTENT_REF_KEY)
493 goto out;
494 key.offset = found_key.offset;
495 if (del) {
496 btrfs_release_path(root, path);
497 continue;
498 }
499 }
500 disk_ref = btrfs_item_ptr(path->nodes[0],
501 path->slots[0],
502 struct btrfs_extent_ref);
503 if (match_extent_ref(path->nodes[0], disk_ref, &ref)) {
504 ret = 0;
505 goto out;
506 }
507 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
508 key.offset = found_key.offset + 1;
509 btrfs_release_path(root, path);
510 }
511 out:
512 return ret;
513 }
514
515 /*
516 * Back reference rules. Back refs have three main goals:
517 *
518 * 1) differentiate between all holders of references to an extent so that
519 * when a reference is dropped we can make sure it was a valid reference
520 * before freeing the extent.
521 *
522 * 2) Provide enough information to quickly find the holders of an extent
523 * if we notice a given block is corrupted or bad.
524 *
525 * 3) Make it easy to migrate blocks for FS shrinking or storage pool
526 * maintenance. This is actually the same as #2, but with a slightly
527 * different use case.
528 *
529 * File extents can be referenced by:
530 *
531 * - multiple snapshots, subvolumes, or different generations in one subvol
532 * - different files inside a single subvolume (in theory, not implemented yet)
533 * - different offsets inside a file (bookend extents in file.c)
534 *
535 * The extent ref structure has fields for:
536 *
537 * - Objectid of the subvolume root
538 * - Generation number of the tree holding the reference
539 * - objectid of the file holding the reference
540 * - offset in the file corresponding to the key holding the reference
541 *
542 * When a file extent is allocated the fields are filled in:
543 * (root_key.objectid, trans->transid, inode objectid, offset in file)
544 *
545 * When a leaf is cow'd new references are added for every file extent found
546 * in the leaf. It looks the same as the create case, but trans->transid
547 * will be different when the block is cow'd.
548 *
549 * (root_key.objectid, trans->transid, inode objectid, offset in file)
550 *
551 * When a file extent is removed either during snapshot deletion or file
552 * truncation, the corresponding back reference is found
553 * by searching for:
554 *
555 * (btrfs_header_owner(leaf), btrfs_header_generation(leaf),
556 * inode objectid, offset in file)
557 *
558 * Btree extents can be referenced by:
559 *
560 * - Different subvolumes
561 * - Different generations of the same subvolume
562 *
563 * Storing sufficient information for a full reverse mapping of a btree
564 * block would require storing the lowest key of the block in the backref,
565 * and it would require updating that lowest key either before write out or
566 * every time it changed. Instead, the objectid of the lowest key is stored
567 * along with the level of the tree block. This provides a hint
568 * about where in the btree the block can be found. Searches through the
569 * btree only need to look for a pointer to that block, so they stop one
570 * level higher than the level recorded in the backref.
571 *
572 * Some btrees do not do reference counting on their extents. These
573 * include the extent tree and the tree of tree roots. Backrefs for these
574 * trees always have a generation of zero.
575 *
576 * When a tree block is created, back references are inserted:
577 *
578 * (root->root_key.objectid, trans->transid or zero, level, lowest_key_objectid)
579 *
580 * When a tree block is cow'd in a reference counted root,
581 * new back references are added for all the blocks it points to.
582 * These are of the form (trans->transid will have increased since creation):
583 *
584 * (root->root_key.objectid, trans->transid, level, lowest_key_objectid)
585 *
586 * Because the lowest_key_objectid and the level are just hints
587 * they are not used when backrefs are deleted. When a backref is deleted:
588 *
589 * if backref was for a tree root:
590 * root_objectid = root->root_key.objectid
591 * else
592 * root_objectid = btrfs_header_owner(parent)
593 *
594 * (root_objectid, btrfs_header_generation(parent) or zero, 0, 0)
595 *
596 * Back Reference Key hashing:
597 *
598 * Back references have four fields, each 64 bits long. Unfortunately,
599 * This is hashed into a single 64 bit number and placed into the key offset.
600 * The key objectid corresponds to the first byte in the extent, and the
601 * key type is set to BTRFS_EXTENT_REF_KEY
602 */
603 int btrfs_insert_extent_backref(struct btrfs_trans_handle *trans,
604 struct btrfs_root *root,
605 struct btrfs_path *path, u64 bytenr,
606 u64 root_objectid, u64 ref_generation,
607 u64 owner, u64 owner_offset)
608 {
609 u64 hash;
610 struct btrfs_key key;
611 struct btrfs_extent_ref ref;
612 struct btrfs_extent_ref *disk_ref;
613 int ret;
614
615 btrfs_set_stack_ref_root(&ref, root_objectid);
616 btrfs_set_stack_ref_generation(&ref, ref_generation);
617 btrfs_set_stack_ref_objectid(&ref, owner);
618 btrfs_set_stack_ref_offset(&ref, owner_offset);
619
620 hash = hash_extent_ref(root_objectid, ref_generation, owner,
621 owner_offset);
622 key.offset = hash;
623 key.objectid = bytenr;
624 key.type = BTRFS_EXTENT_REF_KEY;
625
626 ret = btrfs_insert_empty_item(trans, root, path, &key, sizeof(ref));
627 while (ret == -EEXIST) {
628 disk_ref = btrfs_item_ptr(path->nodes[0], path->slots[0],
629 struct btrfs_extent_ref);
630 if (match_extent_ref(path->nodes[0], disk_ref, &ref))
631 goto out;
632 key.offset++;
633 btrfs_release_path(root, path);
634 ret = btrfs_insert_empty_item(trans, root, path, &key,
635 sizeof(ref));
636 }
637 if (ret)
638 goto out;
639 disk_ref = btrfs_item_ptr(path->nodes[0], path->slots[0],
640 struct btrfs_extent_ref);
641 write_extent_buffer(path->nodes[0], &ref, (unsigned long)disk_ref,
642 sizeof(ref));
643 btrfs_mark_buffer_dirty(path->nodes[0]);
644 out:
645 btrfs_release_path(root, path);
646 return ret;
647 }
648
649 int btrfs_inc_extent_ref(struct btrfs_trans_handle *trans,
650 struct btrfs_root *root,
651 u64 bytenr, u64 num_bytes,
652 u64 root_objectid, u64 ref_generation,
653 u64 owner, u64 owner_offset)
654 {
655 struct btrfs_path *path;
656 int ret;
657 struct btrfs_key key;
658 struct extent_buffer *l;
659 struct btrfs_extent_item *item;
660 u32 refs;
661
662 WARN_ON(num_bytes < root->sectorsize);
663 path = btrfs_alloc_path();
664 if (!path)
665 return -ENOMEM;
666
667 path->reada = 1;
668 key.objectid = bytenr;
669 btrfs_set_key_type(&key, BTRFS_EXTENT_ITEM_KEY);
670 key.offset = num_bytes;
671 ret = btrfs_search_slot(trans, root->fs_info->extent_root, &key, path,
672 0, 1);
673 if (ret < 0)
674 return ret;
675 if (ret != 0) {
676 BUG();
677 }
678 BUG_ON(ret != 0);
679 l = path->nodes[0];
680 item = btrfs_item_ptr(l, path->slots[0], struct btrfs_extent_item);
681 refs = btrfs_extent_refs(l, item);
682 btrfs_set_extent_refs(l, item, refs + 1);
683 btrfs_mark_buffer_dirty(path->nodes[0]);
684
685 btrfs_release_path(root->fs_info->extent_root, path);
686
687 path->reada = 1;
688 ret = btrfs_insert_extent_backref(trans, root->fs_info->extent_root,
689 path, bytenr, root_objectid,
690 ref_generation, owner, owner_offset);
691 BUG_ON(ret);
692 finish_current_insert(trans, root->fs_info->extent_root);
693 del_pending_extents(trans, root->fs_info->extent_root);
694
695 btrfs_free_path(path);
696 return 0;
697 }
698
699 int btrfs_extent_post_op(struct btrfs_trans_handle *trans,
700 struct btrfs_root *root)
701 {
702 finish_current_insert(trans, root->fs_info->extent_root);
703 del_pending_extents(trans, root->fs_info->extent_root);
704 return 0;
705 }
706
707 static int lookup_extent_ref(struct btrfs_trans_handle *trans,
708 struct btrfs_root *root, u64 bytenr,
709 u64 num_bytes, u32 *refs)
710 {
711 struct btrfs_path *path;
712 int ret;
713 struct btrfs_key key;
714 struct extent_buffer *l;
715 struct btrfs_extent_item *item;
716
717 WARN_ON(num_bytes < root->sectorsize);
718 path = btrfs_alloc_path();
719 path->reada = 1;
720 key.objectid = bytenr;
721 key.offset = num_bytes;
722 btrfs_set_key_type(&key, BTRFS_EXTENT_ITEM_KEY);
723 ret = btrfs_search_slot(trans, root->fs_info->extent_root, &key, path,
724 0, 0);
725 if (ret < 0)
726 goto out;
727 if (ret != 0) {
728 btrfs_print_leaf(root, path->nodes[0]);
729 printk("failed to find block number %Lu\n", bytenr);
730 BUG();
731 }
732 l = path->nodes[0];
733 item = btrfs_item_ptr(l, path->slots[0], struct btrfs_extent_item);
734 *refs = btrfs_extent_refs(l, item);
735 out:
736 btrfs_free_path(path);
737 return 0;
738 }
739
740 u32 btrfs_count_snapshots_in_path(struct btrfs_root *root,
741 struct btrfs_path *count_path,
742 u64 expected_owner,
743 u64 first_extent)
744 {
745 struct btrfs_root *extent_root = root->fs_info->extent_root;
746 struct btrfs_path *path;
747 u64 bytenr;
748 u64 found_objectid;
749 u64 found_owner;
750 u64 root_objectid = root->root_key.objectid;
751 u32 total_count = 0;
752 u32 extent_refs;
753 u32 cur_count;
754 u32 nritems;
755 int ret;
756 struct btrfs_key key;
757 struct btrfs_key found_key;
758 struct extent_buffer *l;
759 struct btrfs_extent_item *item;
760 struct btrfs_extent_ref *ref_item;
761 int level = -1;
762
763 path = btrfs_alloc_path();
764 again:
765 if (level == -1)
766 bytenr = first_extent;
767 else
768 bytenr = count_path->nodes[level]->start;
769
770 cur_count = 0;
771 key.objectid = bytenr;
772 key.offset = 0;
773
774 btrfs_set_key_type(&key, BTRFS_EXTENT_ITEM_KEY);
775 ret = btrfs_search_slot(NULL, extent_root, &key, path, 0, 0);
776 if (ret < 0)
777 goto out;
778 BUG_ON(ret == 0);
779
780 l = path->nodes[0];
781 btrfs_item_key_to_cpu(l, &found_key, path->slots[0]);
782
783 if (found_key.objectid != bytenr ||
784 found_key.type != BTRFS_EXTENT_ITEM_KEY) {
785 goto out;
786 }
787
788 item = btrfs_item_ptr(l, path->slots[0], struct btrfs_extent_item);
789 extent_refs = btrfs_extent_refs(l, item);
790 while (1) {
791 l = path->nodes[0];
792 nritems = btrfs_header_nritems(l);
793 if (path->slots[0] >= nritems) {
794 ret = btrfs_next_leaf(extent_root, path);
795 if (ret == 0)
796 continue;
797 break;
798 }
799 btrfs_item_key_to_cpu(l, &found_key, path->slots[0]);
800 if (found_key.objectid != bytenr)
801 break;
802
803 if (found_key.type != BTRFS_EXTENT_REF_KEY) {
804 path->slots[0]++;
805 continue;
806 }
807
808 cur_count++;
809 ref_item = btrfs_item_ptr(l, path->slots[0],
810 struct btrfs_extent_ref);
811 found_objectid = btrfs_ref_root(l, ref_item);
812
813 if (found_objectid != root_objectid) {
814 total_count = 2;
815 goto out;
816 }
817 if (level == -1) {
818 found_owner = btrfs_ref_objectid(l, ref_item);
819 if (found_owner != expected_owner) {
820 total_count = 2;
821 goto out;
822 }
823 /*
824 * nasty. we don't count a reference held by
825 * the running transaction. This allows nodatacow
826 * to avoid cow most of the time
827 */
828 if (found_owner >= BTRFS_FIRST_FREE_OBJECTID &&
829 btrfs_ref_generation(l, ref_item) ==
830 root->fs_info->generation) {
831 extent_refs--;
832 }
833 }
834 total_count = 1;
835 path->slots[0]++;
836 }
837 /*
838 * if there is more than one reference against a data extent,
839 * we have to assume the other ref is another snapshot
840 */
841 if (level == -1 && extent_refs > 1) {
842 total_count = 2;
843 goto out;
844 }
845 if (cur_count == 0) {
846 total_count = 0;
847 goto out;
848 }
849 if (level >= 0 && root->node == count_path->nodes[level])
850 goto out;
851 level++;
852 btrfs_release_path(root, path);
853 goto again;
854
855 out:
856 btrfs_free_path(path);
857 return total_count;
858 }
859 int btrfs_inc_root_ref(struct btrfs_trans_handle *trans,
860 struct btrfs_root *root, u64 owner_objectid)
861 {
862 u64 generation;
863 u64 key_objectid;
864 u64 level;
865 u32 nritems;
866 struct btrfs_disk_key disk_key;
867
868 level = btrfs_header_level(root->node);
869 generation = trans->transid;
870 nritems = btrfs_header_nritems(root->node);
871 if (nritems > 0) {
872 if (level == 0)
873 btrfs_item_key(root->node, &disk_key, 0);
874 else
875 btrfs_node_key(root->node, &disk_key, 0);
876 key_objectid = btrfs_disk_key_objectid(&disk_key);
877 } else {
878 key_objectid = 0;
879 }
880 return btrfs_inc_extent_ref(trans, root, root->node->start,
881 root->node->len, owner_objectid,
882 generation, level, key_objectid);
883 }
884
885 int btrfs_inc_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root,
886 struct extent_buffer *buf)
887 {
888 u64 bytenr;
889 u32 nritems;
890 struct btrfs_key key;
891 struct btrfs_file_extent_item *fi;
892 int i;
893 int level;
894 int ret;
895 int faili;
896
897 if (!root->ref_cows)
898 return 0;
899
900 level = btrfs_header_level(buf);
901 nritems = btrfs_header_nritems(buf);
902 for (i = 0; i < nritems; i++) {
903 if (level == 0) {
904 u64 disk_bytenr;
905 btrfs_item_key_to_cpu(buf, &key, i);
906 if (btrfs_key_type(&key) != BTRFS_EXTENT_DATA_KEY)
907 continue;
908 fi = btrfs_item_ptr(buf, i,
909 struct btrfs_file_extent_item);
910 if (btrfs_file_extent_type(buf, fi) ==
911 BTRFS_FILE_EXTENT_INLINE)
912 continue;
913 disk_bytenr = btrfs_file_extent_disk_bytenr(buf, fi);
914 if (disk_bytenr == 0)
915 continue;
916 ret = btrfs_inc_extent_ref(trans, root, disk_bytenr,
917 btrfs_file_extent_disk_num_bytes(buf, fi),
918 root->root_key.objectid, trans->transid,
919 key.objectid, key.offset);
920 if (ret) {
921 faili = i;
922 goto fail;
923 }
924 } else {
925 bytenr = btrfs_node_blockptr(buf, i);
926 btrfs_node_key_to_cpu(buf, &key, i);
927 ret = btrfs_inc_extent_ref(trans, root, bytenr,
928 btrfs_level_size(root, level - 1),
929 root->root_key.objectid,
930 trans->transid,
931 level - 1, key.objectid);
932 if (ret) {
933 faili = i;
934 goto fail;
935 }
936 }
937 }
938 return 0;
939 fail:
940 WARN_ON(1);
941 #if 0
942 for (i =0; i < faili; i++) {
943 if (level == 0) {
944 u64 disk_bytenr;
945 btrfs_item_key_to_cpu(buf, &key, i);
946 if (btrfs_key_type(&key) != BTRFS_EXTENT_DATA_KEY)
947 continue;
948 fi = btrfs_item_ptr(buf, i,
949 struct btrfs_file_extent_item);
950 if (btrfs_file_extent_type(buf, fi) ==
951 BTRFS_FILE_EXTENT_INLINE)
952 continue;
953 disk_bytenr = btrfs_file_extent_disk_bytenr(buf, fi);
954 if (disk_bytenr == 0)
955 continue;
956 err = btrfs_free_extent(trans, root, disk_bytenr,
957 btrfs_file_extent_disk_num_bytes(buf,
958 fi), 0);
959 BUG_ON(err);
960 } else {
961 bytenr = btrfs_node_blockptr(buf, i);
962 err = btrfs_free_extent(trans, root, bytenr,
963 btrfs_level_size(root, level - 1), 0);
964 BUG_ON(err);
965 }
966 }
967 #endif
968 return ret;
969 }
970
971 static int write_one_cache_group(struct btrfs_trans_handle *trans,
972 struct btrfs_root *root,
973 struct btrfs_path *path,
974 struct btrfs_block_group_cache *cache)
975 {
976 int ret;
977 int pending_ret;
978 struct btrfs_root *extent_root = root->fs_info->extent_root;
979 unsigned long bi;
980 struct extent_buffer *leaf;
981
982 ret = btrfs_search_slot(trans, extent_root, &cache->key, path, 0, 1);
983 if (ret < 0)
984 goto fail;
985 BUG_ON(ret);
986
987 leaf = path->nodes[0];
988 bi = btrfs_item_ptr_offset(leaf, path->slots[0]);
989 write_extent_buffer(leaf, &cache->item, bi, sizeof(cache->item));
990 btrfs_mark_buffer_dirty(leaf);
991 btrfs_release_path(extent_root, path);
992 fail:
993 finish_current_insert(trans, extent_root);
994 pending_ret = del_pending_extents(trans, extent_root);
995 if (ret)
996 return ret;
997 if (pending_ret)
998 return pending_ret;
999 return 0;
1000
1001 }
1002
1003 int btrfs_write_dirty_block_groups(struct btrfs_trans_handle *trans,
1004 struct btrfs_root *root)
1005 {
1006 struct extent_io_tree *block_group_cache;
1007 struct btrfs_block_group_cache *cache;
1008 int ret;
1009 int err = 0;
1010 int werr = 0;
1011 struct btrfs_path *path;
1012 u64 last = 0;
1013 u64 start;
1014 u64 end;
1015 u64 ptr;
1016
1017 block_group_cache = &root->fs_info->block_group_cache;
1018 path = btrfs_alloc_path();
1019 if (!path)
1020 return -ENOMEM;
1021
1022 while(1) {
1023 ret = find_first_extent_bit(block_group_cache, last,
1024 &start, &end, BLOCK_GROUP_DIRTY);
1025 if (ret)
1026 break;
1027
1028 last = end + 1;
1029 ret = get_state_private(block_group_cache, start, &ptr);
1030 if (ret)
1031 break;
1032 cache = (struct btrfs_block_group_cache *)(unsigned long)ptr;
1033 err = write_one_cache_group(trans, root,
1034 path, cache);
1035 /*
1036 * if we fail to write the cache group, we want
1037 * to keep it marked dirty in hopes that a later
1038 * write will work
1039 */
1040 if (err) {
1041 werr = err;
1042 continue;
1043 }
1044 clear_extent_bits(block_group_cache, start, end,
1045 BLOCK_GROUP_DIRTY, GFP_NOFS);
1046 }
1047 btrfs_free_path(path);
1048 return werr;
1049 }
1050
1051 static struct btrfs_space_info *__find_space_info(struct btrfs_fs_info *info,
1052 u64 flags)
1053 {
1054 struct list_head *head = &info->space_info;
1055 struct list_head *cur;
1056 struct btrfs_space_info *found;
1057 list_for_each(cur, head) {
1058 found = list_entry(cur, struct btrfs_space_info, list);
1059 if (found->flags == flags)
1060 return found;
1061 }
1062 return NULL;
1063
1064 }
1065
1066 static int update_space_info(struct btrfs_fs_info *info, u64 flags,
1067 u64 total_bytes, u64 bytes_used,
1068 struct btrfs_space_info **space_info)
1069 {
1070 struct btrfs_space_info *found;
1071
1072 found = __find_space_info(info, flags);
1073 if (found) {
1074 found->total_bytes += total_bytes;
1075 found->bytes_used += bytes_used;
1076 found->full = 0;
1077 WARN_ON(found->total_bytes < found->bytes_used);
1078 *space_info = found;
1079 return 0;
1080 }
1081 found = kmalloc(sizeof(*found), GFP_NOFS);
1082 if (!found)
1083 return -ENOMEM;
1084
1085 list_add(&found->list, &info->space_info);
1086 found->flags = flags;
1087 found->total_bytes = total_bytes;
1088 found->bytes_used = bytes_used;
1089 found->bytes_pinned = 0;
1090 found->full = 0;
1091 found->force_alloc = 0;
1092 *space_info = found;
1093 return 0;
1094 }
1095
1096 static void set_avail_alloc_bits(struct btrfs_fs_info *fs_info, u64 flags)
1097 {
1098 u64 extra_flags = flags & (BTRFS_BLOCK_GROUP_RAID0 |
1099 BTRFS_BLOCK_GROUP_RAID1 |
1100 BTRFS_BLOCK_GROUP_RAID10 |
1101 BTRFS_BLOCK_GROUP_DUP);
1102 if (extra_flags) {
1103 if (flags & BTRFS_BLOCK_GROUP_DATA)
1104 fs_info->avail_data_alloc_bits |= extra_flags;
1105 if (flags & BTRFS_BLOCK_GROUP_METADATA)
1106 fs_info->avail_metadata_alloc_bits |= extra_flags;
1107 if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
1108 fs_info->avail_system_alloc_bits |= extra_flags;
1109 }
1110 }
1111
1112 static u64 reduce_alloc_profile(struct btrfs_root *root, u64 flags)
1113 {
1114 u64 num_devices = root->fs_info->fs_devices->num_devices;
1115
1116 if (num_devices == 1)
1117 flags &= ~(BTRFS_BLOCK_GROUP_RAID1 | BTRFS_BLOCK_GROUP_RAID0);
1118 if (num_devices < 4)
1119 flags &= ~BTRFS_BLOCK_GROUP_RAID10;
1120
1121 if ((flags & BTRFS_BLOCK_GROUP_DUP) &&
1122 (flags & (BTRFS_BLOCK_GROUP_RAID1 |
1123 BTRFS_BLOCK_GROUP_RAID10))) {
1124 flags &= ~BTRFS_BLOCK_GROUP_DUP;
1125 }
1126
1127 if ((flags & BTRFS_BLOCK_GROUP_RAID1) &&
1128 (flags & BTRFS_BLOCK_GROUP_RAID10)) {
1129 flags &= ~BTRFS_BLOCK_GROUP_RAID1;
1130 }
1131
1132 if ((flags & BTRFS_BLOCK_GROUP_RAID0) &&
1133 ((flags & BTRFS_BLOCK_GROUP_RAID1) |
1134 (flags & BTRFS_BLOCK_GROUP_RAID10) |
1135 (flags & BTRFS_BLOCK_GROUP_DUP)))
1136 flags &= ~BTRFS_BLOCK_GROUP_RAID0;
1137 return flags;
1138 }
1139
1140 static int do_chunk_alloc(struct btrfs_trans_handle *trans,
1141 struct btrfs_root *extent_root, u64 alloc_bytes,
1142 u64 flags, int force)
1143 {
1144 struct btrfs_space_info *space_info;
1145 u64 thresh;
1146 u64 start;
1147 u64 num_bytes;
1148 int ret;
1149
1150 flags = reduce_alloc_profile(extent_root, flags);
1151
1152 space_info = __find_space_info(extent_root->fs_info, flags);
1153 if (!space_info) {
1154 ret = update_space_info(extent_root->fs_info, flags,
1155 0, 0, &space_info);
1156 BUG_ON(ret);
1157 }
1158 BUG_ON(!space_info);
1159
1160 if (space_info->force_alloc) {
1161 force = 1;
1162 space_info->force_alloc = 0;
1163 }
1164 if (space_info->full)
1165 return 0;
1166
1167 thresh = div_factor(space_info->total_bytes, 6);
1168 if (!force &&
1169 (space_info->bytes_used + space_info->bytes_pinned + alloc_bytes) <
1170 thresh)
1171 return 0;
1172
1173 ret = btrfs_alloc_chunk(trans, extent_root, &start, &num_bytes, flags);
1174 if (ret == -ENOSPC) {
1175 printk("space info full %Lu\n", flags);
1176 space_info->full = 1;
1177 return 0;
1178 }
1179 BUG_ON(ret);
1180
1181 ret = btrfs_make_block_group(trans, extent_root, 0, flags,
1182 BTRFS_FIRST_CHUNK_TREE_OBJECTID, start, num_bytes);
1183 BUG_ON(ret);
1184
1185 return 0;
1186 }
1187
1188 static int update_block_group(struct btrfs_trans_handle *trans,
1189 struct btrfs_root *root,
1190 u64 bytenr, u64 num_bytes, int alloc,
1191 int mark_free)
1192 {
1193 struct btrfs_block_group_cache *cache;
1194 struct btrfs_fs_info *info = root->fs_info;
1195 u64 total = num_bytes;
1196 u64 old_val;
1197 u64 byte_in_group;
1198 u64 start;
1199 u64 end;
1200
1201 while(total) {
1202 cache = btrfs_lookup_block_group(info, bytenr);
1203 if (!cache) {
1204 return -1;
1205 }
1206 byte_in_group = bytenr - cache->key.objectid;
1207 WARN_ON(byte_in_group > cache->key.offset);
1208 start = cache->key.objectid;
1209 end = start + cache->key.offset - 1;
1210 set_extent_bits(&info->block_group_cache, start, end,
1211 BLOCK_GROUP_DIRTY, GFP_NOFS);
1212
1213 old_val = btrfs_block_group_used(&cache->item);
1214 num_bytes = min(total, cache->key.offset - byte_in_group);
1215 if (alloc) {
1216 old_val += num_bytes;
1217 cache->space_info->bytes_used += num_bytes;
1218 } else {
1219 old_val -= num_bytes;
1220 cache->space_info->bytes_used -= num_bytes;
1221 if (mark_free) {
1222 set_extent_dirty(&info->free_space_cache,
1223 bytenr, bytenr + num_bytes - 1,
1224 GFP_NOFS);
1225 }
1226 }
1227 btrfs_set_block_group_used(&cache->item, old_val);
1228 total -= num_bytes;
1229 bytenr += num_bytes;
1230 }
1231 return 0;
1232 }
1233
1234 static u64 first_logical_byte(struct btrfs_root *root, u64 search_start)
1235 {
1236 u64 start;
1237 u64 end;
1238 int ret;
1239 ret = find_first_extent_bit(&root->fs_info->block_group_cache,
1240 search_start, &start, &end,
1241 BLOCK_GROUP_DATA | BLOCK_GROUP_METADATA |
1242 BLOCK_GROUP_SYSTEM);
1243 if (ret)
1244 return 0;
1245 return start;
1246 }
1247
1248
1249 static int update_pinned_extents(struct btrfs_root *root,
1250 u64 bytenr, u64 num, int pin)
1251 {
1252 u64 len;
1253 struct btrfs_block_group_cache *cache;
1254 struct btrfs_fs_info *fs_info = root->fs_info;
1255
1256 if (pin) {
1257 set_extent_dirty(&fs_info->pinned_extents,
1258 bytenr, bytenr + num - 1, GFP_NOFS);
1259 } else {
1260 clear_extent_dirty(&fs_info->pinned_extents,
1261 bytenr, bytenr + num - 1, GFP_NOFS);
1262 }
1263 while (num > 0) {
1264 cache = btrfs_lookup_block_group(fs_info, bytenr);
1265 if (!cache) {
1266 u64 first = first_logical_byte(root, bytenr);
1267 WARN_ON(first < bytenr);
1268 len = min(first - bytenr, num);
1269 } else {
1270 len = min(num, cache->key.offset -
1271 (bytenr - cache->key.objectid));
1272 }
1273 if (pin) {
1274 if (cache) {
1275 cache->pinned += len;
1276 cache->space_info->bytes_pinned += len;
1277 }
1278 fs_info->total_pinned += len;
1279 } else {
1280 if (cache) {
1281 cache->pinned -= len;
1282 cache->space_info->bytes_pinned -= len;
1283 }
1284 fs_info->total_pinned -= len;
1285 }
1286 bytenr += len;
1287 num -= len;
1288 }
1289 return 0;
1290 }
1291
1292 int btrfs_copy_pinned(struct btrfs_root *root, struct extent_io_tree *copy)
1293 {
1294 u64 last = 0;
1295 u64 start;
1296 u64 end;
1297 struct extent_io_tree *pinned_extents = &root->fs_info->pinned_extents;
1298 int ret;
1299
1300 while(1) {
1301 ret = find_first_extent_bit(pinned_extents, last,
1302 &start, &end, EXTENT_DIRTY);
1303 if (ret)
1304 break;
1305 set_extent_dirty(copy, start, end, GFP_NOFS);
1306 last = end + 1;
1307 }
1308 return 0;
1309 }
1310
1311 int btrfs_finish_extent_commit(struct btrfs_trans_handle *trans,
1312 struct btrfs_root *root,
1313 struct extent_io_tree *unpin)
1314 {
1315 u64 start;
1316 u64 end;
1317 int ret;
1318 struct extent_io_tree *free_space_cache;
1319 free_space_cache = &root->fs_info->free_space_cache;
1320
1321 while(1) {
1322 ret = find_first_extent_bit(unpin, 0, &start, &end,
1323 EXTENT_DIRTY);
1324 if (ret)
1325 break;
1326 update_pinned_extents(root, start, end + 1 - start, 0);
1327 clear_extent_dirty(unpin, start, end, GFP_NOFS);
1328 set_extent_dirty(free_space_cache, start, end, GFP_NOFS);
1329 }
1330 return 0;
1331 }
1332
1333 static int finish_current_insert(struct btrfs_trans_handle *trans,
1334 struct btrfs_root *extent_root)
1335 {
1336 u64 start;
1337 u64 end;
1338 struct btrfs_fs_info *info = extent_root->fs_info;
1339 struct extent_buffer *eb;
1340 struct btrfs_path *path;
1341 struct btrfs_key ins;
1342 struct btrfs_disk_key first;
1343 struct btrfs_extent_item extent_item;
1344 int ret;
1345 int level;
1346 int err = 0;
1347
1348 btrfs_set_stack_extent_refs(&extent_item, 1);
1349 btrfs_set_key_type(&ins, BTRFS_EXTENT_ITEM_KEY);
1350 path = btrfs_alloc_path();
1351
1352 while(1) {
1353 ret = find_first_extent_bit(&info->extent_ins, 0, &start,
1354 &end, EXTENT_LOCKED);
1355 if (ret)
1356 break;
1357
1358 ins.objectid = start;
1359 ins.offset = end + 1 - start;
1360 err = btrfs_insert_item(trans, extent_root, &ins,
1361 &extent_item, sizeof(extent_item));
1362 clear_extent_bits(&info->extent_ins, start, end, EXTENT_LOCKED,
1363 GFP_NOFS);
1364 eb = read_tree_block(extent_root, ins.objectid, ins.offset,
1365 trans->transid);
1366 level = btrfs_header_level(eb);
1367 if (level == 0) {
1368 btrfs_item_key(eb, &first, 0);
1369 } else {
1370 btrfs_node_key(eb, &first, 0);
1371 }
1372 err = btrfs_insert_extent_backref(trans, extent_root, path,
1373 start, extent_root->root_key.objectid,
1374 0, level,
1375 btrfs_disk_key_objectid(&first));
1376 BUG_ON(err);
1377 free_extent_buffer(eb);
1378 }
1379 btrfs_free_path(path);
1380 return 0;
1381 }
1382
1383 static int pin_down_bytes(struct btrfs_root *root, u64 bytenr, u32 num_bytes,
1384 int pending)
1385 {
1386 int err = 0;
1387 struct extent_buffer *buf;
1388
1389 if (!pending) {
1390 buf = btrfs_find_tree_block(root, bytenr, num_bytes);
1391 if (buf) {
1392 if (btrfs_buffer_uptodate(buf, 0)) {
1393 u64 transid =
1394 root->fs_info->running_transaction->transid;
1395 u64 header_transid =
1396 btrfs_header_generation(buf);
1397 if (header_transid == transid &&
1398 !btrfs_header_flag(buf,
1399 BTRFS_HEADER_FLAG_WRITTEN)) {
1400 clean_tree_block(NULL, root, buf);
1401 free_extent_buffer(buf);
1402 return 1;
1403 }
1404 }
1405 free_extent_buffer(buf);
1406 }
1407 update_pinned_extents(root, bytenr, num_bytes, 1);
1408 } else {
1409 set_extent_bits(&root->fs_info->pending_del,
1410 bytenr, bytenr + num_bytes - 1,
1411 EXTENT_LOCKED, GFP_NOFS);
1412 }
1413 BUG_ON(err < 0);
1414 return 0;
1415 }
1416
1417 /*
1418 * remove an extent from the root, returns 0 on success
1419 */
1420 static int __free_extent(struct btrfs_trans_handle *trans, struct btrfs_root
1421 *root, u64 bytenr, u64 num_bytes,
1422 u64 root_objectid, u64 ref_generation,
1423 u64 owner_objectid, u64 owner_offset, int pin,
1424 int mark_free)
1425 {
1426 struct btrfs_path *path;
1427 struct btrfs_key key;
1428 struct btrfs_fs_info *info = root->fs_info;
1429 struct btrfs_root *extent_root = info->extent_root;
1430 struct extent_buffer *leaf;
1431 int ret;
1432 int extent_slot = 0;
1433 int found_extent = 0;
1434 int num_to_del = 1;
1435 struct btrfs_extent_item *ei;
1436 u32 refs;
1437
1438 key.objectid = bytenr;
1439 btrfs_set_key_type(&key, BTRFS_EXTENT_ITEM_KEY);
1440 key.offset = num_bytes;
1441 path = btrfs_alloc_path();
1442 if (!path)
1443 return -ENOMEM;
1444
1445 path->reada = 1;
1446 ret = lookup_extent_backref(trans, extent_root, path,
1447 bytenr, root_objectid,
1448 ref_generation,
1449 owner_objectid, owner_offset, 1);
1450 if (ret == 0) {
1451 struct btrfs_key found_key;
1452 extent_slot = path->slots[0];
1453 while(extent_slot > 0) {
1454 extent_slot--;
1455 btrfs_item_key_to_cpu(path->nodes[0], &found_key,
1456 extent_slot);
1457 if (found_key.objectid != bytenr)
1458 break;
1459 if (found_key.type == BTRFS_EXTENT_ITEM_KEY &&
1460 found_key.offset == num_bytes) {
1461 found_extent = 1;
1462 break;
1463 }
1464 if (path->slots[0] - extent_slot > 5)
1465 break;
1466 }
1467 if (!found_extent)
1468 ret = btrfs_del_item(trans, extent_root, path);
1469 } else {
1470 btrfs_print_leaf(extent_root, path->nodes[0]);
1471 WARN_ON(1);
1472 printk("Unable to find ref byte nr %Lu root %Lu "
1473 " gen %Lu owner %Lu offset %Lu\n", bytenr,
1474 root_objectid, ref_generation, owner_objectid,
1475 owner_offset);
1476 }
1477 if (!found_extent) {
1478 btrfs_release_path(extent_root, path);
1479 ret = btrfs_search_slot(trans, extent_root, &key, path, -1, 1);
1480 if (ret < 0)
1481 return ret;
1482 BUG_ON(ret);
1483 extent_slot = path->slots[0];
1484 }
1485
1486 leaf = path->nodes[0];
1487 ei = btrfs_item_ptr(leaf, extent_slot,
1488 struct btrfs_extent_item);
1489 refs = btrfs_extent_refs(leaf, ei);
1490 BUG_ON(refs == 0);
1491 refs -= 1;
1492 btrfs_set_extent_refs(leaf, ei, refs);
1493
1494 btrfs_mark_buffer_dirty(leaf);
1495
1496 if (refs == 0 && found_extent && path->slots[0] == extent_slot + 1) {
1497 /* if the back ref and the extent are next to each other
1498 * they get deleted below in one shot
1499 */
1500 path->slots[0] = extent_slot;
1501 num_to_del = 2;
1502 } else if (found_extent) {
1503 /* otherwise delete the extent back ref */
1504 ret = btrfs_del_item(trans, extent_root, path);
1505 BUG_ON(ret);
1506 /* if refs are 0, we need to setup the path for deletion */
1507 if (refs == 0) {
1508 btrfs_release_path(extent_root, path);
1509 ret = btrfs_search_slot(trans, extent_root, &key, path,
1510 -1, 1);
1511 if (ret < 0)
1512 return ret;
1513 BUG_ON(ret);
1514 }
1515 }
1516
1517 if (refs == 0) {
1518 u64 super_used;
1519 u64 root_used;
1520
1521 if (pin) {
1522 ret = pin_down_bytes(root, bytenr, num_bytes, 0);
1523 if (ret > 0)
1524 mark_free = 1;
1525 BUG_ON(ret < 0);
1526 }
1527
1528 /* block accounting for super block */
1529 super_used = btrfs_super_bytes_used(&info->super_copy);
1530 btrfs_set_super_bytes_used(&info->super_copy,
1531 super_used - num_bytes);
1532
1533 /* block accounting for root item */
1534 root_used = btrfs_root_used(&root->root_item);
1535 btrfs_set_root_used(&root->root_item,
1536 root_used - num_bytes);
1537 ret = btrfs_del_items(trans, extent_root, path, path->slots[0],
1538 num_to_del);
1539 if (ret) {
1540 return ret;
1541 }
1542 ret = update_block_group(trans, root, bytenr, num_bytes, 0,
1543 mark_free);
1544 BUG_ON(ret);
1545 }
1546 btrfs_free_path(path);
1547 finish_current_insert(trans, extent_root);
1548 return ret;
1549 }
1550
1551 /*
1552 * find all the blocks marked as pending in the radix tree and remove
1553 * them from the extent map
1554 */
1555 static int del_pending_extents(struct btrfs_trans_handle *trans, struct
1556 btrfs_root *extent_root)
1557 {
1558 int ret;
1559 int err = 0;
1560 u64 start;
1561 u64 end;
1562 struct extent_io_tree *pending_del;
1563 struct extent_io_tree *pinned_extents;
1564
1565 pending_del = &extent_root->fs_info->pending_del;
1566 pinned_extents = &extent_root->fs_info->pinned_extents;
1567
1568 while(1) {
1569 ret = find_first_extent_bit(pending_del, 0, &start, &end,
1570 EXTENT_LOCKED);
1571 if (ret)
1572 break;
1573 update_pinned_extents(extent_root, start, end + 1 - start, 1);
1574 clear_extent_bits(pending_del, start, end, EXTENT_LOCKED,
1575 GFP_NOFS);
1576 ret = __free_extent(trans, extent_root,
1577 start, end + 1 - start,
1578 extent_root->root_key.objectid,
1579 0, 0, 0, 0, 0);
1580 if (ret)
1581 err = ret;
1582 }
1583 return err;
1584 }
1585
1586 /*
1587 * remove an extent from the root, returns 0 on success
1588 */
1589 int btrfs_free_extent(struct btrfs_trans_handle *trans, struct btrfs_root
1590 *root, u64 bytenr, u64 num_bytes,
1591 u64 root_objectid, u64 ref_generation,
1592 u64 owner_objectid, u64 owner_offset, int pin)
1593 {
1594 struct btrfs_root *extent_root = root->fs_info->extent_root;
1595 int pending_ret;
1596 int ret;
1597
1598 WARN_ON(num_bytes < root->sectorsize);
1599 if (!root->ref_cows)
1600 ref_generation = 0;
1601
1602 if (root == extent_root) {
1603 pin_down_bytes(root, bytenr, num_bytes, 1);
1604 return 0;
1605 }
1606 ret = __free_extent(trans, root, bytenr, num_bytes, root_objectid,
1607 ref_generation, owner_objectid, owner_offset,
1608 pin, pin == 0);
1609 pending_ret = del_pending_extents(trans, root->fs_info->extent_root);
1610 return ret ? ret : pending_ret;
1611 }
1612
1613 static u64 stripe_align(struct btrfs_root *root, u64 val)
1614 {
1615 u64 mask = ((u64)root->stripesize - 1);
1616 u64 ret = (val + mask) & ~mask;
1617 return ret;
1618 }
1619
1620 /*
1621 * walks the btree of allocated extents and find a hole of a given size.
1622 * The key ins is changed to record the hole:
1623 * ins->objectid == block start
1624 * ins->flags = BTRFS_EXTENT_ITEM_KEY
1625 * ins->offset == number of blocks
1626 * Any available blocks before search_start are skipped.
1627 */
1628 static int noinline find_free_extent(struct btrfs_trans_handle *trans,
1629 struct btrfs_root *orig_root,
1630 u64 num_bytes, u64 empty_size,
1631 u64 search_start, u64 search_end,
1632 u64 hint_byte, struct btrfs_key *ins,
1633 u64 exclude_start, u64 exclude_nr,
1634 int data)
1635 {
1636 int ret;
1637 u64 orig_search_start;
1638 struct btrfs_root * root = orig_root->fs_info->extent_root;
1639 struct btrfs_fs_info *info = root->fs_info;
1640 u64 total_needed = num_bytes;
1641 u64 *last_ptr = NULL;
1642 struct btrfs_block_group_cache *block_group;
1643 int full_scan = 0;
1644 int wrapped = 0;
1645 int chunk_alloc_done = 0;
1646 int empty_cluster = 2 * 1024 * 1024;
1647 int allowed_chunk_alloc = 0;
1648
1649 WARN_ON(num_bytes < root->sectorsize);
1650 btrfs_set_key_type(ins, BTRFS_EXTENT_ITEM_KEY);
1651
1652 if (orig_root->ref_cows || empty_size)
1653 allowed_chunk_alloc = 1;
1654
1655 if (data & BTRFS_BLOCK_GROUP_METADATA) {
1656 last_ptr = &root->fs_info->last_alloc;
1657 empty_cluster = 256 * 1024;
1658 }
1659
1660 if ((data & BTRFS_BLOCK_GROUP_DATA) && btrfs_test_opt(root, SSD)) {
1661 last_ptr = &root->fs_info->last_data_alloc;
1662 }
1663
1664 if (last_ptr) {
1665 if (*last_ptr)
1666 hint_byte = *last_ptr;
1667 else {
1668 empty_size += empty_cluster;
1669 }
1670 }
1671
1672 search_start = max(search_start, first_logical_byte(root, 0));
1673 orig_search_start = search_start;
1674
1675 if (search_end == (u64)-1)
1676 search_end = btrfs_super_total_bytes(&info->super_copy);
1677
1678 if (hint_byte) {
1679 block_group = btrfs_lookup_first_block_group(info, hint_byte);
1680 if (!block_group)
1681 hint_byte = search_start;
1682 block_group = btrfs_find_block_group(root, block_group,
1683 hint_byte, data, 1);
1684 if (last_ptr && *last_ptr == 0 && block_group)
1685 hint_byte = block_group->key.objectid;
1686 } else {
1687 block_group = btrfs_find_block_group(root,
1688 trans->block_group,
1689 search_start, data, 1);
1690 }
1691 search_start = max(search_start, hint_byte);
1692
1693 total_needed += empty_size;
1694
1695 check_failed:
1696 if (!block_group) {
1697 block_group = btrfs_lookup_first_block_group(info,
1698 search_start);
1699 if (!block_group)
1700 block_group = btrfs_lookup_first_block_group(info,
1701 orig_search_start);
1702 }
1703 if (full_scan && !chunk_alloc_done) {
1704 if (allowed_chunk_alloc) {
1705 do_chunk_alloc(trans, root,
1706 num_bytes + 2 * 1024 * 1024, data, 1);
1707 allowed_chunk_alloc = 0;
1708 } else if (block_group && block_group_bits(block_group, data)) {
1709 block_group->space_info->force_alloc = 1;
1710 }
1711 chunk_alloc_done = 1;
1712 }
1713 ret = find_search_start(root, &block_group, &search_start,
1714 total_needed, data);
1715 if (ret == -ENOSPC && last_ptr && *last_ptr) {
1716 *last_ptr = 0;
1717 block_group = btrfs_lookup_first_block_group(info,
1718 orig_search_start);
1719 search_start = orig_search_start;
1720 ret = find_search_start(root, &block_group, &search_start,
1721 total_needed, data);
1722 }
1723 if (ret == -ENOSPC)
1724 goto enospc;
1725 if (ret)
1726 goto error;
1727
1728 if (last_ptr && *last_ptr && search_start != *last_ptr) {
1729 *last_ptr = 0;
1730 if (!empty_size) {
1731 empty_size += empty_cluster;
1732 total_needed += empty_size;
1733 }
1734 block_group = btrfs_lookup_first_block_group(info,
1735 orig_search_start);
1736 search_start = orig_search_start;
1737 ret = find_search_start(root, &block_group,
1738 &search_start, total_needed, data);
1739 if (ret == -ENOSPC)
1740 goto enospc;
1741 if (ret)
1742 goto error;
1743 }
1744
1745 search_start = stripe_align(root, search_start);
1746 ins->objectid = search_start;
1747 ins->offset = num_bytes;
1748
1749 if (ins->objectid + num_bytes >= search_end)
1750 goto enospc;
1751
1752 if (ins->objectid + num_bytes >
1753 block_group->key.objectid + block_group->key.offset) {
1754 search_start = block_group->key.objectid +
1755 block_group->key.offset;
1756 goto new_group;
1757 }
1758
1759 if (test_range_bit(&info->extent_ins, ins->objectid,
1760 ins->objectid + num_bytes -1, EXTENT_LOCKED, 0)) {
1761 search_start = ins->objectid + num_bytes;
1762 goto new_group;
1763 }
1764
1765 if (test_range_bit(&info->pinned_extents, ins->objectid,
1766 ins->objectid + num_bytes -1, EXTENT_DIRTY, 0)) {
1767 search_start = ins->objectid + num_bytes;
1768 goto new_group;
1769 }
1770
1771 if (exclude_nr > 0 && (ins->objectid + num_bytes > exclude_start &&
1772 ins->objectid < exclude_start + exclude_nr)) {
1773 search_start = exclude_start + exclude_nr;
1774 goto new_group;
1775 }
1776
1777 if (!(data & BTRFS_BLOCK_GROUP_DATA)) {
1778 block_group = btrfs_lookup_block_group(info, ins->objectid);
1779 if (block_group)
1780 trans->block_group = block_group;
1781 }
1782 ins->offset = num_bytes;
1783 if (last_ptr) {
1784 *last_ptr = ins->objectid + ins->offset;
1785 if (*last_ptr ==
1786 btrfs_super_total_bytes(&root->fs_info->super_copy)) {
1787 *last_ptr = 0;
1788 }
1789 }
1790 return 0;
1791
1792 new_group:
1793 if (search_start + num_bytes >= search_end) {
1794 enospc:
1795 search_start = orig_search_start;
1796 if (full_scan) {
1797 ret = -ENOSPC;
1798 goto error;
1799 }
1800 if (wrapped) {
1801 if (!full_scan)
1802 total_needed -= empty_size;
1803 full_scan = 1;
1804 } else
1805 wrapped = 1;
1806 }
1807 block_group = btrfs_lookup_first_block_group(info, search_start);
1808 cond_resched();
1809 block_group = btrfs_find_block_group(root, block_group,
1810 search_start, data, 0);
1811 goto check_failed;
1812
1813 error:
1814 return ret;
1815 }
1816
1817 /*
1818 * finds a free extent and does all the dirty work required for allocation
1819 * returns the key for the extent through ins, and a tree buffer for
1820 * the first block of the extent through buf.
1821 *
1822 * returns 0 if everything worked, non-zero otherwise.
1823 */
1824 int btrfs_alloc_extent(struct btrfs_trans_handle *trans,
1825 struct btrfs_root *root,
1826 u64 num_bytes, u64 min_alloc_size,
1827 u64 root_objectid, u64 ref_generation,
1828 u64 owner, u64 owner_offset,
1829 u64 empty_size, u64 hint_byte,
1830 u64 search_end, struct btrfs_key *ins, u64 data)
1831 {
1832 int ret;
1833 int pending_ret;
1834 u64 super_used;
1835 u64 root_used;
1836 u64 search_start = 0;
1837 u64 alloc_profile;
1838 u32 sizes[2];
1839 struct btrfs_fs_info *info = root->fs_info;
1840 struct btrfs_root *extent_root = info->extent_root;
1841 struct btrfs_extent_item *extent_item;
1842 struct btrfs_extent_ref *ref;
1843 struct btrfs_path *path;
1844 struct btrfs_key keys[2];
1845
1846 if (data) {
1847 alloc_profile = info->avail_data_alloc_bits &
1848 info->data_alloc_profile;
1849 data = BTRFS_BLOCK_GROUP_DATA | alloc_profile;
1850 } else if (root == root->fs_info->chunk_root) {
1851 alloc_profile = info->avail_system_alloc_bits &
1852 info->system_alloc_profile;
1853 data = BTRFS_BLOCK_GROUP_SYSTEM | alloc_profile;
1854 } else {
1855 alloc_profile = info->avail_metadata_alloc_bits &
1856 info->metadata_alloc_profile;
1857 data = BTRFS_BLOCK_GROUP_METADATA | alloc_profile;
1858 }
1859 again:
1860 data = reduce_alloc_profile(root, data);
1861 /*
1862 * the only place that sets empty_size is btrfs_realloc_node, which
1863 * is not called recursively on allocations
1864 */
1865 if (empty_size || root->ref_cows) {
1866 if (!(data & BTRFS_BLOCK_GROUP_METADATA)) {
1867 ret = do_chunk_alloc(trans, root->fs_info->extent_root,
1868 2 * 1024 * 1024,
1869 BTRFS_BLOCK_GROUP_METADATA |
1870 (info->metadata_alloc_profile &
1871 info->avail_metadata_alloc_bits), 0);
1872 BUG_ON(ret);
1873 }
1874 ret = do_chunk_alloc(trans, root->fs_info->extent_root,
1875 num_bytes + 2 * 1024 * 1024, data, 0);
1876 BUG_ON(ret);
1877 }
1878
1879 WARN_ON(num_bytes < root->sectorsize);
1880 ret = find_free_extent(trans, root, num_bytes, empty_size,
1881 search_start, search_end, hint_byte, ins,
1882 trans->alloc_exclude_start,
1883 trans->alloc_exclude_nr, data);
1884
1885 if (ret == -ENOSPC && num_bytes > min_alloc_size) {
1886 num_bytes = num_bytes >> 1;
1887 num_bytes = max(num_bytes, min_alloc_size);
1888 do_chunk_alloc(trans, root->fs_info->extent_root,
1889 num_bytes, data, 1);
1890 goto again;
1891 }
1892 if (ret) {
1893 printk("allocation failed flags %Lu\n", data);
1894 }
1895 BUG_ON(ret);
1896 if (ret)
1897 return ret;
1898
1899 /* block accounting for super block */
1900 super_used = btrfs_super_bytes_used(&info->super_copy);
1901 btrfs_set_super_bytes_used(&info->super_copy, super_used + num_bytes);
1902
1903 /* block accounting for root item */
1904 root_used = btrfs_root_used(&root->root_item);
1905 btrfs_set_root_used(&root->root_item, root_used + num_bytes);
1906
1907 clear_extent_dirty(&root->fs_info->free_space_cache,
1908 ins->objectid, ins->objectid + ins->offset - 1,
1909 GFP_NOFS);
1910
1911 if (root == extent_root) {
1912 set_extent_bits(&root->fs_info->extent_ins, ins->objectid,
1913 ins->objectid + ins->offset - 1,
1914 EXTENT_LOCKED, GFP_NOFS);
1915 goto update_block;
1916 }
1917
1918 WARN_ON(trans->alloc_exclude_nr);
1919 trans->alloc_exclude_start = ins->objectid;
1920 trans->alloc_exclude_nr = ins->offset;
1921
1922 memcpy(&keys[0], ins, sizeof(*ins));
1923 keys[1].offset = hash_extent_ref(root_objectid, ref_generation,
1924 owner, owner_offset);
1925 keys[1].objectid = ins->objectid;
1926 keys[1].type = BTRFS_EXTENT_REF_KEY;
1927 sizes[0] = sizeof(*extent_item);
1928 sizes[1] = sizeof(*ref);
1929
1930 path = btrfs_alloc_path();
1931 BUG_ON(!path);
1932
1933 ret = btrfs_insert_empty_items(trans, extent_root, path, keys,
1934 sizes, 2);
1935
1936 BUG_ON(ret);
1937 extent_item = btrfs_item_ptr(path->nodes[0], path->slots[0],
1938 struct btrfs_extent_item);
1939 btrfs_set_extent_refs(path->nodes[0], extent_item, 1);
1940 ref = btrfs_item_ptr(path->nodes[0], path->slots[0] + 1,
1941 struct btrfs_extent_ref);
1942
1943 btrfs_set_ref_root(path->nodes[0], ref, root_objectid);
1944 btrfs_set_ref_generation(path->nodes[0], ref, ref_generation);
1945 btrfs_set_ref_objectid(path->nodes[0], ref, owner);
1946 btrfs_set_ref_offset(path->nodes[0], ref, owner_offset);
1947
1948 btrfs_mark_buffer_dirty(path->nodes[0]);
1949
1950 trans->alloc_exclude_start = 0;
1951 trans->alloc_exclude_nr = 0;
1952 btrfs_free_path(path);
1953 finish_current_insert(trans, extent_root);
1954 pending_ret = del_pending_extents(trans, extent_root);
1955
1956 if (ret) {
1957 return ret;
1958 }
1959 if (pending_ret) {
1960 return pending_ret;
1961 }
1962
1963 update_block:
1964 ret = update_block_group(trans, root, ins->objectid, ins->offset, 1, 0);
1965 if (ret) {
1966 printk("update block group failed for %Lu %Lu\n",
1967 ins->objectid, ins->offset);
1968 BUG();
1969 }
1970 return 0;
1971 }
1972
1973 /*
1974 * helper function to allocate a block for a given tree
1975 * returns the tree buffer or NULL.
1976 */
1977 struct extent_buffer *btrfs_alloc_free_block(struct btrfs_trans_handle *trans,
1978 struct btrfs_root *root,
1979 u32 blocksize,
1980 u64 root_objectid, u64 hint,
1981 u64 empty_size)
1982 {
1983 u64 ref_generation;
1984
1985 if (root->ref_cows)
1986 ref_generation = trans->transid;
1987 else
1988 ref_generation = 0;
1989
1990
1991 return __btrfs_alloc_free_block(trans, root, blocksize, root_objectid,
1992 ref_generation, 0, 0, hint, empty_size);
1993 }
1994
1995 /*
1996 * helper function to allocate a block for a given tree
1997 * returns the tree buffer or NULL.
1998 */
1999 struct extent_buffer *__btrfs_alloc_free_block(struct btrfs_trans_handle *trans,
2000 struct btrfs_root *root,
2001 u32 blocksize,
2002 u64 root_objectid,
2003 u64 ref_generation,
2004 u64 first_objectid,
2005 int level,
2006 u64 hint,
2007 u64 empty_size)
2008 {
2009 struct btrfs_key ins;
2010 int ret;
2011 struct extent_buffer *buf;
2012
2013 ret = btrfs_alloc_extent(trans, root, blocksize, blocksize,
2014 root_objectid, ref_generation,
2015 level, first_objectid, empty_size, hint,
2016 (u64)-1, &ins, 0);
2017 if (ret) {
2018 BUG_ON(ret > 0);
2019 return ERR_PTR(ret);
2020 }
2021 buf = btrfs_find_create_tree_block(root, ins.objectid, blocksize);
2022 if (!buf) {
2023 btrfs_free_extent(trans, root, ins.objectid, blocksize,
2024 root->root_key.objectid, ref_generation,
2025 0, 0, 0);
2026 return ERR_PTR(-ENOMEM);
2027 }
2028 btrfs_set_header_generation(buf, trans->transid);
2029 clean_tree_block(trans, root, buf);
2030 btrfs_set_buffer_uptodate(buf);
2031
2032 if (PageDirty(buf->first_page)) {
2033 printk("page %lu dirty\n", buf->first_page->index);
2034 WARN_ON(1);
2035 }
2036
2037 set_extent_dirty(&trans->transaction->dirty_pages, buf->start,
2038 buf->start + buf->len - 1, GFP_NOFS);
2039 if (!btrfs_test_opt(root, SSD))
2040 btrfs_set_buffer_defrag(buf);
2041 trans->blocks_used++;
2042 return buf;
2043 }
2044
2045 static int noinline drop_leaf_ref(struct btrfs_trans_handle *trans,
2046 struct btrfs_root *root,
2047 struct extent_buffer *leaf)
2048 {
2049 u64 leaf_owner;
2050 u64 leaf_generation;
2051 struct btrfs_key key;
2052 struct btrfs_file_extent_item *fi;
2053 int i;
2054 int nritems;
2055 int ret;
2056
2057 BUG_ON(!btrfs_is_leaf(leaf));
2058 nritems = btrfs_header_nritems(leaf);
2059 leaf_owner = btrfs_header_owner(leaf);
2060 leaf_generation = btrfs_header_generation(leaf);
2061
2062 for (i = 0; i < nritems; i++) {
2063 u64 disk_bytenr;
2064
2065 btrfs_item_key_to_cpu(leaf, &key, i);
2066 if (btrfs_key_type(&key) != BTRFS_EXTENT_DATA_KEY)
2067 continue;
2068 fi = btrfs_item_ptr(leaf, i, struct btrfs_file_extent_item);
2069 if (btrfs_file_extent_type(leaf, fi) ==
2070 BTRFS_FILE_EXTENT_INLINE)
2071 continue;
2072 /*
2073 * FIXME make sure to insert a trans record that
2074 * repeats the snapshot del on crash
2075 */
2076 disk_bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
2077 if (disk_bytenr == 0)
2078 continue;
2079 ret = btrfs_free_extent(trans, root, disk_bytenr,
2080 btrfs_file_extent_disk_num_bytes(leaf, fi),
2081 leaf_owner, leaf_generation,
2082 key.objectid, key.offset, 0);
2083 BUG_ON(ret);
2084 }
2085 return 0;
2086 }
2087
2088 static void noinline reada_walk_down(struct btrfs_root *root,
2089 struct extent_buffer *node,
2090 int slot)
2091 {
2092 u64 bytenr;
2093 u64 last = 0;
2094 u32 nritems;
2095 u32 refs;
2096 u32 blocksize;
2097 int ret;
2098 int i;
2099 int level;
2100 int skipped = 0;
2101
2102 nritems = btrfs_header_nritems(node);
2103 level = btrfs_header_level(node);
2104 if (level)
2105 return;
2106
2107 for (i = slot; i < nritems && skipped < 32; i++) {
2108 bytenr = btrfs_node_blockptr(node, i);
2109 if (last && ((bytenr > last && bytenr - last > 32 * 1024) ||
2110 (last > bytenr && last - bytenr > 32 * 1024))) {
2111 skipped++;
2112 continue;
2113 }
2114 blocksize = btrfs_level_size(root, level - 1);
2115 if (i != slot) {
2116 ret = lookup_extent_ref(NULL, root, bytenr,
2117 blocksize, &refs);
2118 BUG_ON(ret);
2119 if (refs != 1) {
2120 skipped++;
2121 continue;
2122 }
2123 }
2124 mutex_unlock(&root->fs_info->fs_mutex);
2125 ret = readahead_tree_block(root, bytenr, blocksize,
2126 btrfs_node_ptr_generation(node, i));
2127 last = bytenr + blocksize;
2128 cond_resched();
2129 mutex_lock(&root->fs_info->fs_mutex);
2130 if (ret)
2131 break;
2132 }
2133 }
2134
2135 /*
2136 * helper function for drop_snapshot, this walks down the tree dropping ref
2137 * counts as it goes.
2138 */
2139 static int noinline walk_down_tree(struct btrfs_trans_handle *trans,
2140 struct btrfs_root *root,
2141 struct btrfs_path *path, int *level)
2142 {
2143 u64 root_owner;
2144 u64 root_gen;
2145 u64 bytenr;
2146 u64 ptr_gen;
2147 struct extent_buffer *next;
2148 struct extent_buffer *cur;
2149 struct extent_buffer *parent;
2150 u32 blocksize;
2151 int ret;
2152 u32 refs;
2153
2154 WARN_ON(*level < 0);
2155 WARN_ON(*level >= BTRFS_MAX_LEVEL);
2156 ret = lookup_extent_ref(trans, root,
2157 path->nodes[*level]->start,
2158 path->nodes[*level]->len, &refs);
2159 BUG_ON(ret);
2160 if (refs > 1)
2161 goto out;
2162
2163 /*
2164 * walk down to the last node level and free all the leaves
2165 */
2166 while(*level >= 0) {
2167 WARN_ON(*level < 0);
2168 WARN_ON(*level >= BTRFS_MAX_LEVEL);
2169 cur = path->nodes[*level];
2170
2171 if (btrfs_header_level(cur) != *level)
2172 WARN_ON(1);
2173
2174 if (path->slots[*level] >=
2175 btrfs_header_nritems(cur))
2176 break;
2177 if (*level == 0) {
2178 ret = drop_leaf_ref(trans, root, cur);
2179 BUG_ON(ret);
2180 break;
2181 }
2182 bytenr = btrfs_node_blockptr(cur, path->slots[*level]);
2183 ptr_gen = btrfs_node_ptr_generation(cur, path->slots[*level]);
2184 blocksize = btrfs_level_size(root, *level - 1);
2185 ret = lookup_extent_ref(trans, root, bytenr, blocksize, &refs);
2186 BUG_ON(ret);
2187 if (refs != 1) {
2188 parent = path->nodes[*level];
2189 root_owner = btrfs_header_owner(parent);
2190 root_gen = btrfs_header_generation(parent);
2191 path->slots[*level]++;
2192 ret = btrfs_free_extent(trans, root, bytenr,
2193 blocksize, root_owner,
2194 root_gen, 0, 0, 1);
2195 BUG_ON(ret);
2196 continue;
2197 }
2198 next = btrfs_find_tree_block(root, bytenr, blocksize);
2199 if (!next || !btrfs_buffer_uptodate(next, ptr_gen)) {
2200 free_extent_buffer(next);
2201 reada_walk_down(root, cur, path->slots[*level]);
2202
2203 mutex_unlock(&root->fs_info->fs_mutex);
2204 next = read_tree_block(root, bytenr, blocksize,
2205 ptr_gen);
2206 mutex_lock(&root->fs_info->fs_mutex);
2207
2208 /* we've dropped the lock, double check */
2209 ret = lookup_extent_ref(trans, root, bytenr,
2210 blocksize, &refs);
2211 BUG_ON(ret);
2212 if (refs != 1) {
2213 parent = path->nodes[*level];
2214 root_owner = btrfs_header_owner(parent);
2215 root_gen = btrfs_header_generation(parent);
2216
2217 path->slots[*level]++;
2218 free_extent_buffer(next);
2219 ret = btrfs_free_extent(trans, root, bytenr,
2220 blocksize,
2221 root_owner,
2222 root_gen, 0, 0, 1);
2223 BUG_ON(ret);
2224 continue;
2225 }
2226 }
2227 WARN_ON(*level <= 0);
2228 if (path->nodes[*level-1])
2229 free_extent_buffer(path->nodes[*level-1]);
2230 path->nodes[*level-1] = next;
2231 *level = btrfs_header_level(next);
2232 path->slots[*level] = 0;
2233 }
2234 out:
2235 WARN_ON(*level < 0);
2236 WARN_ON(*level >= BTRFS_MAX_LEVEL);
2237
2238 if (path->nodes[*level] == root->node) {
2239 root_owner = root->root_key.objectid;
2240 parent = path->nodes[*level];
2241 } else {
2242 parent = path->nodes[*level + 1];
2243 root_owner = btrfs_header_owner(parent);
2244 }
2245
2246 root_gen = btrfs_header_generation(parent);
2247 ret = btrfs_free_extent(trans, root, path->nodes[*level]->start,
2248 path->nodes[*level]->len,
2249 root_owner, root_gen, 0, 0, 1);
2250 free_extent_buffer(path->nodes[*level]);
2251 path->nodes[*level] = NULL;
2252 *level += 1;
2253 BUG_ON(ret);
2254 return 0;
2255 }
2256
2257 /*
2258 * helper for dropping snapshots. This walks back up the tree in the path
2259 * to find the first node higher up where we haven't yet gone through
2260 * all the slots
2261 */
2262 static int noinline walk_up_tree(struct btrfs_trans_handle *trans,
2263 struct btrfs_root *root,
2264 struct btrfs_path *path, int *level)
2265 {
2266 u64 root_owner;
2267 u64 root_gen;
2268 struct btrfs_root_item *root_item = &root->root_item;
2269 int i;
2270 int slot;
2271 int ret;
2272
2273 for(i = *level; i < BTRFS_MAX_LEVEL - 1 && path->nodes[i]; i++) {
2274 slot = path->slots[i];
2275 if (slot < btrfs_header_nritems(path->nodes[i]) - 1) {
2276 struct extent_buffer *node;
2277 struct btrfs_disk_key disk_key;
2278 node = path->nodes[i];
2279 path->slots[i]++;
2280 *level = i;
2281 WARN_ON(*level == 0);
2282 btrfs_node_key(node, &disk_key, path->slots[i]);
2283 memcpy(&root_item->drop_progress,
2284 &disk_key, sizeof(disk_key));
2285 root_item->drop_level = i;
2286 return 0;
2287 } else {
2288 if (path->nodes[*level] == root->node) {
2289 root_owner = root->root_key.objectid;
2290 root_gen =
2291 btrfs_header_generation(path->nodes[*level]);
2292 } else {
2293 struct extent_buffer *node;
2294 node = path->nodes[*level + 1];
2295 root_owner = btrfs_header_owner(node);
2296 root_gen = btrfs_header_generation(node);
2297 }
2298 ret = btrfs_free_extent(trans, root,
2299 path->nodes[*level]->start,
2300 path->nodes[*level]->len,
2301 root_owner, root_gen, 0, 0, 1);
2302 BUG_ON(ret);
2303 free_extent_buffer(path->nodes[*level]);
2304 path->nodes[*level] = NULL;
2305 *level = i + 1;
2306 }
2307 }
2308 return 1;
2309 }
2310
2311 /*
2312 * drop the reference count on the tree rooted at 'snap'. This traverses
2313 * the tree freeing any blocks that have a ref count of zero after being
2314 * decremented.
2315 */
2316 int btrfs_drop_snapshot(struct btrfs_trans_handle *trans, struct btrfs_root
2317 *root)
2318 {
2319 int ret = 0;
2320 int wret;
2321 int level;
2322 struct btrfs_path *path;
2323 int i;
2324 int orig_level;
2325 struct btrfs_root_item *root_item = &root->root_item;
2326
2327 path = btrfs_alloc_path();
2328 BUG_ON(!path);
2329
2330 level = btrfs_header_level(root->node);
2331 orig_level = level;
2332 if (btrfs_disk_key_objectid(&root_item->drop_progress) == 0) {
2333 path->nodes[level] = root->node;
2334 extent_buffer_get(root->node);
2335 path->slots[level] = 0;
2336 } else {
2337 struct btrfs_key key;
2338 struct btrfs_disk_key found_key;
2339 struct extent_buffer *node;
2340
2341 btrfs_disk_key_to_cpu(&key, &root_item->drop_progress);
2342 level = root_item->drop_level;
2343 path->lowest_level = level;
2344 wret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
2345 if (wret < 0) {
2346 ret = wret;
2347 goto out;
2348 }
2349 node = path->nodes[level];
2350 btrfs_node_key(node, &found_key, path->slots[level]);
2351 WARN_ON(memcmp(&found_key, &root_item->drop_progress,
2352 sizeof(found_key)));
2353 }
2354 while(1) {
2355 wret = walk_down_tree(trans, root, path, &level);
2356 if (wret > 0)
2357 break;
2358 if (wret < 0)
2359 ret = wret;
2360
2361 wret = walk_up_tree(trans, root, path, &level);
2362 if (wret > 0)
2363 break;
2364 if (wret < 0)
2365 ret = wret;
2366 ret = -EAGAIN;
2367 break;
2368 }
2369 for (i = 0; i <= orig_level; i++) {
2370 if (path->nodes[i]) {
2371 free_extent_buffer(path->nodes[i]);
2372 path->nodes[i] = NULL;
2373 }
2374 }
2375 out:
2376 btrfs_free_path(path);
2377 return ret;
2378 }
2379
2380 int btrfs_free_block_groups(struct btrfs_fs_info *info)
2381 {
2382 u64 start;
2383 u64 end;
2384 u64 ptr;
2385 int ret;
2386 while(1) {
2387 ret = find_first_extent_bit(&info->block_group_cache, 0,
2388 &start, &end, (unsigned int)-1);
2389 if (ret)
2390 break;
2391 ret = get_state_private(&info->block_group_cache, start, &ptr);
2392 if (!ret)
2393 kfree((void *)(unsigned long)ptr);
2394 clear_extent_bits(&info->block_group_cache, start,
2395 end, (unsigned int)-1, GFP_NOFS);
2396 }
2397 while(1) {
2398 ret = find_first_extent_bit(&info->free_space_cache, 0,
2399 &start, &end, EXTENT_DIRTY);
2400 if (ret)
2401 break;
2402 clear_extent_dirty(&info->free_space_cache, start,
2403 end, GFP_NOFS);
2404 }
2405 return 0;
2406 }
2407
2408 static unsigned long calc_ra(unsigned long start, unsigned long last,
2409 unsigned long nr)
2410 {
2411 return min(last, start + nr - 1);
2412 }
2413
2414 static int noinline relocate_inode_pages(struct inode *inode, u64 start,
2415 u64 len)
2416 {
2417 u64 page_start;
2418 u64 page_end;
2419 unsigned long last_index;
2420 unsigned long i;
2421 struct page *page;
2422 struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
2423 struct file_ra_state *ra;
2424 unsigned long total_read = 0;
2425 unsigned long ra_pages;
2426 struct btrfs_trans_handle *trans;
2427
2428 ra = kzalloc(sizeof(*ra), GFP_NOFS);
2429
2430 mutex_lock(&inode->i_mutex);
2431 i = start >> PAGE_CACHE_SHIFT;
2432 last_index = (start + len - 1) >> PAGE_CACHE_SHIFT;
2433
2434 ra_pages = BTRFS_I(inode)->root->fs_info->bdi.ra_pages;
2435
2436 file_ra_state_init(ra, inode->i_mapping);
2437
2438 for (; i <= last_index; i++) {
2439 if (total_read % ra_pages == 0) {
2440 btrfs_force_ra(inode->i_mapping, ra, NULL, i,
2441 calc_ra(i, last_index, ra_pages));
2442 }
2443 total_read++;
2444 if (((u64)i << PAGE_CACHE_SHIFT) > inode->i_size)
2445 goto truncate_racing;
2446
2447 page = grab_cache_page(inode->i_mapping, i);
2448 if (!page) {
2449 goto out_unlock;
2450 }
2451 if (!PageUptodate(page)) {
2452 btrfs_readpage(NULL, page);
2453 lock_page(page);
2454 if (!PageUptodate(page)) {
2455 unlock_page(page);
2456 page_cache_release(page);
2457 goto out_unlock;
2458 }
2459 }
2460 #if LINUX_VERSION_CODE <= KERNEL_VERSION(2,6,18)
2461 ClearPageDirty(page);
2462 #else
2463 cancel_dirty_page(page, PAGE_CACHE_SIZE);
2464 #endif
2465 wait_on_page_writeback(page);
2466 set_page_extent_mapped(page);
2467 page_start = (u64)page->index << PAGE_CACHE_SHIFT;
2468 page_end = page_start + PAGE_CACHE_SIZE - 1;
2469
2470 lock_extent(io_tree, page_start, page_end, GFP_NOFS);
2471
2472 set_extent_delalloc(io_tree, page_start,
2473 page_end, GFP_NOFS);
2474 set_page_dirty(page);
2475
2476 unlock_extent(io_tree, page_start, page_end, GFP_NOFS);
2477 unlock_page(page);
2478 page_cache_release(page);
2479 }
2480 balance_dirty_pages_ratelimited_nr(inode->i_mapping,
2481 total_read);
2482
2483 out_unlock:
2484 kfree(ra);
2485 trans = btrfs_start_transaction(BTRFS_I(inode)->root, 1);
2486 if (trans) {
2487 btrfs_add_ordered_inode(inode);
2488 btrfs_end_transaction(trans, BTRFS_I(inode)->root);
2489 mark_inode_dirty(inode);
2490 }
2491 mutex_unlock(&inode->i_mutex);
2492 return 0;
2493
2494 truncate_racing:
2495 vmtruncate(inode, inode->i_size);
2496 balance_dirty_pages_ratelimited_nr(inode->i_mapping,
2497 total_read);
2498 goto out_unlock;
2499 }
2500
2501 /*
2502 * The back references tell us which tree holds a ref on a block,
2503 * but it is possible for the tree root field in the reference to
2504 * reflect the original root before a snapshot was made. In this
2505 * case we should search through all the children of a given root
2506 * to find potential holders of references on a block.
2507 *
2508 * Instead, we do something a little less fancy and just search
2509 * all the roots for a given key/block combination.
2510 */
2511 static int find_root_for_ref(struct btrfs_root *root,
2512 struct btrfs_path *path,
2513 struct btrfs_key *key0,
2514 int level,
2515 int file_key,
2516 struct btrfs_root **found_root,
2517 u64 bytenr)
2518 {
2519 struct btrfs_key root_location;
2520 struct btrfs_root *cur_root = *found_root;
2521 struct btrfs_file_extent_item *file_extent;
2522 u64 root_search_start = BTRFS_FS_TREE_OBJECTID;
2523 u64 found_bytenr;
2524 int ret;
2525 int i;
2526
2527 root_location.offset = (u64)-1;
2528 root_location.type = BTRFS_ROOT_ITEM_KEY;
2529 path->lowest_level = level;
2530 path->reada = 0;
2531 while(1) {
2532 ret = btrfs_search_slot(NULL, cur_root, key0, path, 0, 0);
2533 found_bytenr = 0;
2534 if (ret == 0 && file_key) {
2535 struct extent_buffer *leaf = path->nodes[0];
2536 file_extent = btrfs_item_ptr(leaf, path->slots[0],
2537 struct btrfs_file_extent_item);
2538 if (btrfs_file_extent_type(leaf, file_extent) ==
2539 BTRFS_FILE_EXTENT_REG) {
2540 found_bytenr =
2541 btrfs_file_extent_disk_bytenr(leaf,
2542 file_extent);
2543 }
2544 } else if (!file_key) {
2545 if (path->nodes[level])
2546 found_bytenr = path->nodes[level]->start;
2547 }
2548
2549 for (i = level; i < BTRFS_MAX_LEVEL; i++) {
2550 if (!path->nodes[i])
2551 break;
2552 free_extent_buffer(path->nodes[i]);
2553 path->nodes[i] = NULL;
2554 }
2555 btrfs_release_path(cur_root, path);
2556
2557 if (found_bytenr == bytenr) {
2558 *found_root = cur_root;
2559 ret = 0;
2560 goto out;
2561 }
2562 ret = btrfs_search_root(root->fs_info->tree_root,
2563 root_search_start, &root_search_start);
2564 if (ret)
2565 break;
2566
2567 root_location.objectid = root_search_start;
2568 cur_root = btrfs_read_fs_root_no_name(root->fs_info,
2569 &root_location);
2570 if (!cur_root) {
2571 ret = 1;
2572 break;
2573 }
2574 }
2575 out:
2576 path->lowest_level = 0;
2577 return ret;
2578 }
2579
2580 /*
2581 * note, this releases the path
2582 */
2583 static int noinline relocate_one_reference(struct btrfs_root *extent_root,
2584 struct btrfs_path *path,
2585 struct btrfs_key *extent_key,
2586 u64 *last_file_objectid,
2587 u64 *last_file_offset,
2588 u64 *last_file_root,
2589 u64 last_extent)
2590 {
2591 struct inode *inode;
2592 struct btrfs_root *found_root;
2593 struct btrfs_key root_location;
2594 struct btrfs_key found_key;
2595 struct btrfs_extent_ref *ref;
2596 u64 ref_root;
2597 u64 ref_gen;
2598 u64 ref_objectid;
2599 u64 ref_offset;
2600 int ret;
2601 int level;
2602
2603 ref = btrfs_item_ptr(path->nodes[0], path->slots[0],
2604 struct btrfs_extent_ref);
2605 ref_root = btrfs_ref_root(path->nodes[0], ref);
2606 ref_gen = btrfs_ref_generation(path->nodes[0], ref);
2607 ref_objectid = btrfs_ref_objectid(path->nodes[0], ref);
2608 ref_offset = btrfs_ref_offset(path->nodes[0], ref);
2609 btrfs_release_path(extent_root, path);
2610
2611 root_location.objectid = ref_root;
2612 if (ref_gen == 0)
2613 root_location.offset = 0;
2614 else
2615 root_location.offset = (u64)-1;
2616 root_location.type = BTRFS_ROOT_ITEM_KEY;
2617
2618 found_root = btrfs_read_fs_root_no_name(extent_root->fs_info,
2619 &root_location);
2620 BUG_ON(!found_root);
2621
2622 if (ref_objectid >= BTRFS_FIRST_FREE_OBJECTID) {
2623 found_key.objectid = ref_objectid;
2624 found_key.type = BTRFS_EXTENT_DATA_KEY;
2625 found_key.offset = ref_offset;
2626 level = 0;
2627
2628 if (last_extent == extent_key->objectid &&
2629 *last_file_objectid == ref_objectid &&
2630 *last_file_offset == ref_offset &&
2631 *last_file_root == ref_root)
2632 goto out;
2633
2634 ret = find_root_for_ref(extent_root, path, &found_key,
2635 level, 1, &found_root,
2636 extent_key->objectid);
2637
2638 if (ret)
2639 goto out;
2640
2641 if (last_extent == extent_key->objectid &&
2642 *last_file_objectid == ref_objectid &&
2643 *last_file_offset == ref_offset &&
2644 *last_file_root == ref_root)
2645 goto out;
2646
2647 mutex_unlock(&extent_root->fs_info->fs_mutex);
2648 inode = btrfs_iget_locked(extent_root->fs_info->sb,
2649 ref_objectid, found_root);
2650 if (inode->i_state & I_NEW) {
2651 /* the inode and parent dir are two different roots */
2652 BTRFS_I(inode)->root = found_root;
2653 BTRFS_I(inode)->location.objectid = ref_objectid;
2654 BTRFS_I(inode)->location.type = BTRFS_INODE_ITEM_KEY;
2655 BTRFS_I(inode)->location.offset = 0;
2656 btrfs_read_locked_inode(inode);
2657 unlock_new_inode(inode);
2658
2659 }
2660 /* this can happen if the reference is not against
2661 * the latest version of the tree root
2662 */
2663 if (is_bad_inode(inode)) {
2664 mutex_lock(&extent_root->fs_info->fs_mutex);
2665 goto out;
2666 }
2667 *last_file_objectid = inode->i_ino;
2668 *last_file_root = found_root->root_key.objectid;
2669 *last_file_offset = ref_offset;
2670
2671 relocate_inode_pages(inode, ref_offset, extent_key->offset);
2672 iput(inode);
2673 mutex_lock(&extent_root->fs_info->fs_mutex);
2674 } else {
2675 struct btrfs_trans_handle *trans;
2676 struct extent_buffer *eb;
2677 int i;
2678
2679 eb = read_tree_block(found_root, extent_key->objectid,
2680 extent_key->offset, 0);
2681 level = btrfs_header_level(eb);
2682
2683 if (level == 0)
2684 btrfs_item_key_to_cpu(eb, &found_key, 0);
2685 else
2686 btrfs_node_key_to_cpu(eb, &found_key, 0);
2687
2688 free_extent_buffer(eb);
2689
2690 ret = find_root_for_ref(extent_root, path, &found_key,
2691 level, 0, &found_root,
2692 extent_key->objectid);
2693
2694 if (ret)
2695 goto out;
2696
2697 trans = btrfs_start_transaction(found_root, 1);
2698
2699 path->lowest_level = level;
2700 path->reada = 2;
2701 ret = btrfs_search_slot(trans, found_root, &found_key, path,
2702 0, 1);
2703 path->lowest_level = 0;
2704 for (i = level; i < BTRFS_MAX_LEVEL; i++) {
2705 if (!path->nodes[i])
2706 break;
2707 free_extent_buffer(path->nodes[i]);
2708 path->nodes[i] = NULL;
2709 }
2710 btrfs_release_path(found_root, path);
2711 if (found_root == found_root->fs_info->extent_root)
2712 btrfs_extent_post_op(trans, found_root);
2713 btrfs_end_transaction(trans, found_root);
2714 }
2715
2716 out:
2717 return 0;
2718 }
2719
2720 static int noinline del_extent_zero(struct btrfs_root *extent_root,
2721 struct btrfs_path *path,
2722 struct btrfs_key *extent_key)
2723 {
2724 int ret;
2725 struct btrfs_trans_handle *trans;
2726
2727 trans = btrfs_start_transaction(extent_root, 1);
2728 ret = btrfs_search_slot(trans, extent_root, extent_key, path, -1, 1);
2729 if (ret > 0) {
2730 ret = -EIO;
2731 goto out;
2732 }
2733 if (ret < 0)
2734 goto out;
2735 ret = btrfs_del_item(trans, extent_root, path);
2736 out:
2737 btrfs_end_transaction(trans, extent_root);
2738 return ret;
2739 }
2740
2741 static int noinline relocate_one_extent(struct btrfs_root *extent_root,
2742 struct btrfs_path *path,
2743 struct btrfs_key *extent_key)
2744 {
2745 struct btrfs_key key;
2746 struct btrfs_key found_key;
2747 struct extent_buffer *leaf;
2748 u64 last_file_objectid = 0;
2749 u64 last_file_root = 0;
2750 u64 last_file_offset = (u64)-1;
2751 u64 last_extent = 0;
2752 u32 nritems;
2753 u32 item_size;
2754 int ret = 0;
2755
2756 if (extent_key->objectid == 0) {
2757 ret = del_extent_zero(extent_root, path, extent_key);
2758 goto out;
2759 }
2760 key.objectid = extent_key->objectid;
2761 key.type = BTRFS_EXTENT_REF_KEY;
2762 key.offset = 0;
2763
2764 while(1) {
2765 ret = btrfs_search_slot(NULL, extent_root, &key, path, 0, 0);
2766
2767 if (ret < 0)
2768 goto out;
2769
2770 ret = 0;
2771 leaf = path->nodes[0];
2772 nritems = btrfs_header_nritems(leaf);
2773 if (path->slots[0] == nritems) {
2774 ret = btrfs_next_leaf(extent_root, path);
2775 if (ret > 0) {
2776 ret = 0;
2777 goto out;
2778 }
2779 if (ret < 0)
2780 goto out;
2781 leaf = path->nodes[0];
2782 }
2783
2784 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
2785 if (found_key.objectid != extent_key->objectid) {
2786 break;
2787 }
2788
2789 if (found_key.type != BTRFS_EXTENT_REF_KEY) {
2790 break;
2791 }
2792
2793 key.offset = found_key.offset + 1;
2794 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
2795
2796 ret = relocate_one_reference(extent_root, path, extent_key,
2797 &last_file_objectid,
2798 &last_file_offset,
2799 &last_file_root, last_extent);
2800 if (ret)
2801 goto out;
2802 last_extent = extent_key->objectid;
2803 }
2804 ret = 0;
2805 out:
2806 btrfs_release_path(extent_root, path);
2807 return ret;
2808 }
2809
2810 static u64 update_block_group_flags(struct btrfs_root *root, u64 flags)
2811 {
2812 u64 num_devices;
2813 u64 stripped = BTRFS_BLOCK_GROUP_RAID0 |
2814 BTRFS_BLOCK_GROUP_RAID1 | BTRFS_BLOCK_GROUP_RAID10;
2815
2816 num_devices = root->fs_info->fs_devices->num_devices;
2817 if (num_devices == 1) {
2818 stripped |= BTRFS_BLOCK_GROUP_DUP;
2819 stripped = flags & ~stripped;
2820
2821 /* turn raid0 into single device chunks */
2822 if (flags & BTRFS_BLOCK_GROUP_RAID0)
2823 return stripped;
2824
2825 /* turn mirroring into duplication */
2826 if (flags & (BTRFS_BLOCK_GROUP_RAID1 |
2827 BTRFS_BLOCK_GROUP_RAID10))
2828 return stripped | BTRFS_BLOCK_GROUP_DUP;
2829 return flags;
2830 } else {
2831 /* they already had raid on here, just return */
2832 if (flags & stripped)
2833 return flags;
2834
2835 stripped |= BTRFS_BLOCK_GROUP_DUP;
2836 stripped = flags & ~stripped;
2837
2838 /* switch duplicated blocks with raid1 */
2839 if (flags & BTRFS_BLOCK_GROUP_DUP)
2840 return stripped | BTRFS_BLOCK_GROUP_RAID1;
2841
2842 /* turn single device chunks into raid0 */
2843 return stripped | BTRFS_BLOCK_GROUP_RAID0;
2844 }
2845 return flags;
2846 }
2847
2848 int __alloc_chunk_for_shrink(struct btrfs_root *root,
2849 struct btrfs_block_group_cache *shrink_block_group,
2850 int force)
2851 {
2852 struct btrfs_trans_handle *trans;
2853 u64 new_alloc_flags;
2854 u64 calc;
2855
2856 if (btrfs_block_group_used(&shrink_block_group->item) > 0) {
2857
2858 trans = btrfs_start_transaction(root, 1);
2859 new_alloc_flags = update_block_group_flags(root,
2860 shrink_block_group->flags);
2861 if (new_alloc_flags != shrink_block_group->flags) {
2862 calc =
2863 btrfs_block_group_used(&shrink_block_group->item);
2864 } else {
2865 calc = shrink_block_group->key.offset;
2866 }
2867 do_chunk_alloc(trans, root->fs_info->extent_root,
2868 calc + 2 * 1024 * 1024, new_alloc_flags, force);
2869 btrfs_end_transaction(trans, root);
2870 }
2871 return 0;
2872 }
2873
2874 int btrfs_shrink_extent_tree(struct btrfs_root *root, u64 shrink_start)
2875 {
2876 struct btrfs_trans_handle *trans;
2877 struct btrfs_root *tree_root = root->fs_info->tree_root;
2878 struct btrfs_path *path;
2879 u64 cur_byte;
2880 u64 total_found;
2881 u64 shrink_last_byte;
2882 struct btrfs_block_group_cache *shrink_block_group;
2883 struct btrfs_fs_info *info = root->fs_info;
2884 struct btrfs_key key;
2885 struct btrfs_key found_key;
2886 struct extent_buffer *leaf;
2887 u32 nritems;
2888 int ret;
2889 int progress;
2890
2891 shrink_block_group = btrfs_lookup_block_group(root->fs_info,
2892 shrink_start);
2893 BUG_ON(!shrink_block_group);
2894
2895 shrink_last_byte = shrink_block_group->key.objectid +
2896 shrink_block_group->key.offset;
2897
2898 shrink_block_group->space_info->total_bytes -=
2899 shrink_block_group->key.offset;
2900 path = btrfs_alloc_path();
2901 root = root->fs_info->extent_root;
2902 path->reada = 2;
2903
2904 printk("btrfs relocating block group %llu flags %llu\n",
2905 (unsigned long long)shrink_start,
2906 (unsigned long long)shrink_block_group->flags);
2907
2908 __alloc_chunk_for_shrink(root, shrink_block_group, 1);
2909
2910 again:
2911
2912 shrink_block_group->ro = 1;
2913
2914 total_found = 0;
2915 progress = 0;
2916 key.objectid = shrink_start;
2917 key.offset = 0;
2918 key.type = 0;
2919 cur_byte = key.objectid;
2920
2921 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
2922 if (ret < 0)
2923 goto out;
2924
2925 ret = btrfs_previous_item(root, path, 0, BTRFS_EXTENT_ITEM_KEY);
2926 if (ret < 0)
2927 goto out;
2928
2929 if (ret == 0) {
2930 leaf = path->nodes[0];
2931 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
2932 if (found_key.objectid + found_key.offset > shrink_start &&
2933 found_key.objectid < shrink_last_byte) {
2934 cur_byte = found_key.objectid;
2935 key.objectid = cur_byte;
2936 }
2937 }
2938 btrfs_release_path(root, path);
2939
2940 while(1) {
2941 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
2942 if (ret < 0)
2943 goto out;
2944
2945 leaf = path->nodes[0];
2946 nritems = btrfs_header_nritems(leaf);
2947 next:
2948 if (path->slots[0] >= nritems) {
2949 ret = btrfs_next_leaf(root, path);
2950 if (ret < 0)
2951 goto out;
2952 if (ret == 1) {
2953 ret = 0;
2954 break;
2955 }
2956 leaf = path->nodes[0];
2957 nritems = btrfs_header_nritems(leaf);
2958 }
2959
2960 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
2961
2962 if (found_key.objectid >= shrink_last_byte)
2963 break;
2964
2965 if (progress && need_resched()) {
2966 memcpy(&key, &found_key, sizeof(key));
2967 mutex_unlock(&root->fs_info->fs_mutex);
2968 cond_resched();
2969 mutex_lock(&root->fs_info->fs_mutex);
2970 btrfs_release_path(root, path);
2971 btrfs_search_slot(NULL, root, &key, path, 0, 0);
2972 progress = 0;
2973 goto next;
2974 }
2975 progress = 1;
2976
2977 if (btrfs_key_type(&found_key) != BTRFS_EXTENT_ITEM_KEY ||
2978 found_key.objectid + found_key.offset <= cur_byte) {
2979 memcpy(&key, &found_key, sizeof(key));
2980 key.offset++;
2981 path->slots[0]++;
2982 goto next;
2983 }
2984
2985 total_found++;
2986 cur_byte = found_key.objectid + found_key.offset;
2987 key.objectid = cur_byte;
2988 btrfs_release_path(root, path);
2989 ret = relocate_one_extent(root, path, &found_key);
2990 __alloc_chunk_for_shrink(root, shrink_block_group, 0);
2991 }
2992
2993 btrfs_release_path(root, path);
2994
2995 if (total_found > 0) {
2996 printk("btrfs relocate found %llu last extent was %llu\n",
2997 (unsigned long long)total_found,
2998 (unsigned long long)found_key.objectid);
2999 trans = btrfs_start_transaction(tree_root, 1);
3000 btrfs_commit_transaction(trans, tree_root);
3001
3002 mutex_unlock(&root->fs_info->fs_mutex);
3003 btrfs_clean_old_snapshots(tree_root);
3004 mutex_lock(&root->fs_info->fs_mutex);
3005
3006 trans = btrfs_start_transaction(tree_root, 1);
3007 btrfs_commit_transaction(trans, tree_root);
3008 goto again;
3009 }
3010
3011 /*
3012 * we've freed all the extents, now remove the block
3013 * group item from the tree
3014 */
3015 trans = btrfs_start_transaction(root, 1);
3016 memcpy(&key, &shrink_block_group->key, sizeof(key));
3017
3018 ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
3019 if (ret > 0)
3020 ret = -EIO;
3021 if (ret < 0)
3022 goto out;
3023
3024 clear_extent_bits(&info->block_group_cache, key.objectid,
3025 key.objectid + key.offset - 1,
3026 (unsigned int)-1, GFP_NOFS);
3027
3028
3029 clear_extent_bits(&info->free_space_cache,
3030 key.objectid, key.objectid + key.offset - 1,
3031 (unsigned int)-1, GFP_NOFS);
3032
3033 memset(shrink_block_group, 0, sizeof(*shrink_block_group));
3034 kfree(shrink_block_group);
3035
3036 btrfs_del_item(trans, root, path);
3037 btrfs_commit_transaction(trans, root);
3038
3039 /* the code to unpin extents might set a few bits in the free
3040 * space cache for this range again
3041 */
3042 clear_extent_bits(&info->free_space_cache,
3043 key.objectid, key.objectid + key.offset - 1,
3044 (unsigned int)-1, GFP_NOFS);
3045 out:
3046 btrfs_free_path(path);
3047 return ret;
3048 }
3049
3050 int find_first_block_group(struct btrfs_root *root, struct btrfs_path *path,
3051 struct btrfs_key *key)
3052 {
3053 int ret;
3054 struct btrfs_key found_key;
3055 struct extent_buffer *leaf;
3056 int slot;
3057
3058 ret = btrfs_search_slot(NULL, root, key, path, 0, 0);
3059 if (ret < 0)
3060 return ret;
3061 while(1) {
3062 slot = path->slots[0];
3063 leaf = path->nodes[0];
3064 if (slot >= btrfs_header_nritems(leaf)) {
3065 ret = btrfs_next_leaf(root, path);
3066 if (ret == 0)
3067 continue;
3068 if (ret < 0)
3069 goto error;
3070 break;
3071 }
3072 btrfs_item_key_to_cpu(leaf, &found_key, slot);
3073
3074 if (found_key.objectid >= key->objectid &&
3075 found_key.type == BTRFS_BLOCK_GROUP_ITEM_KEY)
3076 return 0;
3077 path->slots[0]++;
3078 }
3079 ret = -ENOENT;
3080 error:
3081 return ret;
3082 }
3083
3084 int btrfs_read_block_groups(struct btrfs_root *root)
3085 {
3086 struct btrfs_path *path;
3087 int ret;
3088 int bit;
3089 struct btrfs_block_group_cache *cache;
3090 struct btrfs_fs_info *info = root->fs_info;
3091 struct btrfs_space_info *space_info;
3092 struct extent_io_tree *block_group_cache;
3093 struct btrfs_key key;
3094 struct btrfs_key found_key;
3095 struct extent_buffer *leaf;
3096
3097 block_group_cache = &info->block_group_cache;
3098 root = info->extent_root;
3099 key.objectid = 0;
3100 key.offset = 0;
3101 btrfs_set_key_type(&key, BTRFS_BLOCK_GROUP_ITEM_KEY);
3102 path = btrfs_alloc_path();
3103 if (!path)
3104 return -ENOMEM;
3105
3106 while(1) {
3107 ret = find_first_block_group(root, path, &key);
3108 if (ret > 0) {
3109 ret = 0;
3110 goto error;
3111 }
3112 if (ret != 0)
3113 goto error;
3114
3115 leaf = path->nodes[0];
3116 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
3117 cache = kzalloc(sizeof(*cache), GFP_NOFS);
3118 if (!cache) {
3119 ret = -ENOMEM;
3120 break;
3121 }
3122
3123 read_extent_buffer(leaf, &cache->item,
3124 btrfs_item_ptr_offset(leaf, path->slots[0]),
3125 sizeof(cache->item));
3126 memcpy(&cache->key, &found_key, sizeof(found_key));
3127
3128 key.objectid = found_key.objectid + found_key.offset;
3129 btrfs_release_path(root, path);
3130 cache->flags = btrfs_block_group_flags(&cache->item);
3131 bit = 0;
3132 if (cache->flags & BTRFS_BLOCK_GROUP_DATA) {
3133 bit = BLOCK_GROUP_DATA;
3134 } else if (cache->flags & BTRFS_BLOCK_GROUP_SYSTEM) {
3135 bit = BLOCK_GROUP_SYSTEM;
3136 } else if (cache->flags & BTRFS_BLOCK_GROUP_METADATA) {
3137 bit = BLOCK_GROUP_METADATA;
3138 }
3139 set_avail_alloc_bits(info, cache->flags);
3140
3141 ret = update_space_info(info, cache->flags, found_key.offset,
3142 btrfs_block_group_used(&cache->item),
3143 &space_info);
3144 BUG_ON(ret);
3145 cache->space_info = space_info;
3146
3147 /* use EXTENT_LOCKED to prevent merging */
3148 set_extent_bits(block_group_cache, found_key.objectid,
3149 found_key.objectid + found_key.offset - 1,
3150 bit | EXTENT_LOCKED, GFP_NOFS);
3151 set_state_private(block_group_cache, found_key.objectid,
3152 (unsigned long)cache);
3153
3154 if (key.objectid >=
3155 btrfs_super_total_bytes(&info->super_copy))
3156 break;
3157 }
3158 ret = 0;
3159 error:
3160 btrfs_free_path(path);
3161 return ret;
3162 }
3163
3164 int btrfs_make_block_group(struct btrfs_trans_handle *trans,
3165 struct btrfs_root *root, u64 bytes_used,
3166 u64 type, u64 chunk_objectid, u64 chunk_offset,
3167 u64 size)
3168 {
3169 int ret;
3170 int bit = 0;
3171 struct btrfs_root *extent_root;
3172 struct btrfs_block_group_cache *cache;
3173 struct extent_io_tree *block_group_cache;
3174
3175 extent_root = root->fs_info->extent_root;
3176 block_group_cache = &root->fs_info->block_group_cache;
3177
3178 cache = kzalloc(sizeof(*cache), GFP_NOFS);
3179 BUG_ON(!cache);
3180 cache->key.objectid = chunk_offset;
3181 cache->key.offset = size;
3182 btrfs_set_key_type(&cache->key, BTRFS_BLOCK_GROUP_ITEM_KEY);
3183
3184 btrfs_set_block_group_used(&cache->item, bytes_used);
3185 btrfs_set_block_group_chunk_objectid(&cache->item, chunk_objectid);
3186 cache->flags = type;
3187 btrfs_set_block_group_flags(&cache->item, type);
3188
3189 ret = update_space_info(root->fs_info, cache->flags, size, bytes_used,
3190 &cache->space_info);
3191 BUG_ON(ret);
3192
3193 bit = block_group_state_bits(type);
3194 set_extent_bits(block_group_cache, chunk_offset,
3195 chunk_offset + size - 1,
3196 bit | EXTENT_LOCKED, GFP_NOFS);
3197
3198 set_state_private(block_group_cache, chunk_offset,
3199 (unsigned long)cache);
3200 ret = btrfs_insert_item(trans, extent_root, &cache->key, &cache->item,
3201 sizeof(cache->item));
3202 BUG_ON(ret);
3203
3204 finish_current_insert(trans, extent_root);
3205 ret = del_pending_extents(trans, extent_root);
3206 BUG_ON(ret);
3207 set_avail_alloc_bits(extent_root->fs_info, type);
3208 return 0;
3209 }
Linux kernel - Deliverables
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