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Disk format changes required for write ahead tree log
[btrfs-progs-unstable.git] / extent-tree.c
blob767867f98fb76d326ba6d0c83365d562d66f3f13
1 /*
2 * Copyright (C) 2007 Oracle. All rights reserved.
3 *
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU General Public
6 * License v2 as published by the Free Software Foundation.
7 *
8 * This program is distributed in the hope that it will be useful,
9 * but WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
11 * General Public License for more details.
12 *
13 * You should have received a copy of the GNU General Public
14 * License along with this program; if not, write to the
15 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
16 * Boston, MA 021110-1307, USA.
17 */
18
19 #include <stdio.h>
20 #include <stdlib.h>
21 #include "kerncompat.h"
22 #include "radix-tree.h"
23 #include "ctree.h"
24 #include "disk-io.h"
25 #include "print-tree.h"
26 #include "transaction.h"
27 #include "crc32c.h"
28 #include "volumes.h"
29
30 #define BLOCK_GROUP_DATA EXTENT_WRITEBACK
31 #define BLOCK_GROUP_METADATA EXTENT_UPTODATE
32 #define BLOCK_GROUP_SYSTEM EXTENT_NEW
33
34 #define BLOCK_GROUP_DIRTY EXTENT_DIRTY
35
36 static int finish_current_insert(struct btrfs_trans_handle *trans, struct
37 btrfs_root *extent_root);
38 static int del_pending_extents(struct btrfs_trans_handle *trans, struct
39 btrfs_root *extent_root);
40
41 static int cache_block_group(struct btrfs_root *root,
42 struct btrfs_block_group_cache *block_group)
43 {
44 struct btrfs_path *path;
45 int ret;
46 struct btrfs_key key;
47 struct extent_buffer *leaf;
48 struct extent_io_tree *free_space_cache;
49 int slot;
50 u64 last = 0;
51 u64 hole_size;
52 u64 first_free;
53 int found = 0;
54
55 if (!block_group)
56 return 0;
57
58 root = root->fs_info->extent_root;
59 free_space_cache = &root->fs_info->free_space_cache;
60
61 if (block_group->cached)
62 return 0;
63
64 path = btrfs_alloc_path();
65 if (!path)
66 return -ENOMEM;
67
68 path->reada = 2;
69 first_free = block_group->key.objectid;
70 key.objectid = block_group->key.objectid;
71 key.offset = 0;
72 btrfs_set_key_type(&key, BTRFS_EXTENT_ITEM_KEY);
73 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
74 if (ret < 0)
75 return ret;
76 ret = btrfs_previous_item(root, path, 0, BTRFS_EXTENT_ITEM_KEY);
77 if (ret < 0)
78 return ret;
79 if (ret == 0) {
80 leaf = path->nodes[0];
81 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
82 if (key.objectid + key.offset > first_free)
83 first_free = key.objectid + key.offset;
84 }
85 while(1) {
86 leaf = path->nodes[0];
87 slot = path->slots[0];
88 if (slot >= btrfs_header_nritems(leaf)) {
89 ret = btrfs_next_leaf(root, path);
90 if (ret < 0)
91 goto err;
92 if (ret == 0) {
93 continue;
94 } else {
95 break;
96 }
97 }
98 btrfs_item_key_to_cpu(leaf, &key, slot);
99 if (key.objectid < block_group->key.objectid) {
100 goto next;
101 }
102 if (key.objectid >= block_group->key.objectid +
103 block_group->key.offset) {
104 break;
105 }
106
107 if (btrfs_key_type(&key) == BTRFS_EXTENT_ITEM_KEY) {
108 if (!found) {
109 last = first_free;
110 found = 1;
111 }
112 if (key.objectid > last) {
113 hole_size = key.objectid - last;
114 set_extent_dirty(free_space_cache, last,
115 last + hole_size - 1,
116 GFP_NOFS);
117 }
118 last = key.objectid + key.offset;
119 }
120 next:
121 path->slots[0]++;
122 }
123
124 if (!found)
125 last = first_free;
126 if (block_group->key.objectid +
127 block_group->key.offset > last) {
128 hole_size = block_group->key.objectid +
129 block_group->key.offset - last;
130 set_extent_dirty(free_space_cache, last,
131 last + hole_size - 1, GFP_NOFS);
132 }
133 block_group->cached = 1;
134 err:
135 btrfs_free_path(path);
136 return 0;
137 }
138
139 struct btrfs_block_group_cache *btrfs_lookup_block_group(struct
140 btrfs_fs_info *info,
141 u64 bytenr)
142 {
143 struct extent_io_tree *block_group_cache;
144 struct btrfs_block_group_cache *block_group = NULL;
145 u64 ptr;
146 u64 start;
147 u64 end;
148 int ret;
149
150 block_group_cache = &info->block_group_cache;
151 ret = find_first_extent_bit(block_group_cache,
152 bytenr, &start, &end,
153 BLOCK_GROUP_DATA | BLOCK_GROUP_METADATA |
154 BLOCK_GROUP_SYSTEM);
155 if (ret) {
156 return NULL;
157 }
158 ret = get_state_private(block_group_cache, start, &ptr);
159 if (ret)
160 return NULL;
161
162 block_group = (struct btrfs_block_group_cache *)(unsigned long)ptr;
163 if (block_group->key.objectid <= bytenr && bytenr <
164 block_group->key.objectid + block_group->key.offset)
165 return block_group;
166 return NULL;
167 }
168
169 static int block_group_bits(struct btrfs_block_group_cache *cache, u64 bits)
170 {
171 return (cache->flags & bits) == bits;
172 }
173
174 static int noinline find_search_start(struct btrfs_root *root,
175 struct btrfs_block_group_cache **cache_ret,
176 u64 *start_ret, int num, int data)
177 {
178 int ret;
179 struct btrfs_block_group_cache *cache = *cache_ret;
180 u64 last;
181 u64 start = 0;
182 u64 end = 0;
183 u64 cache_miss = 0;
184 u64 search_start = *start_ret;
185 int wrapped = 0;
186
187 if (!cache) {
188 goto out;
189 }
190 again:
191 ret = cache_block_group(root, cache);
192 if (ret)
193 goto out;
194
195 last = max(search_start, cache->key.objectid);
196 if (!block_group_bits(cache, data)) {
197 goto new_group;
198 }
199
200 while(1) {
201 ret = find_first_extent_bit(&root->fs_info->free_space_cache,
202 last, &start, &end, EXTENT_DIRTY);
203 if (ret) {
204 if (!cache_miss)
205 cache_miss = last;
206 goto new_group;
207 }
208
209 start = max(last, start);
210 last = end + 1;
211 if (last - start < num) {
212 if (last == cache->key.objectid + cache->key.offset)
213 cache_miss = start;
214 continue;
215 }
216 if (start + num > cache->key.objectid + cache->key.offset)
217 goto new_group;
218 *start_ret = start;
219 return 0;
220 }
221 out:
222 cache = btrfs_lookup_block_group(root->fs_info, search_start);
223 if (!cache) {
224 printk("Unable to find block group for %llu\n",
225 (unsigned long long)search_start);
226 WARN_ON(1);
227 }
228 return -ENOSPC;
229
230 new_group:
231 last = cache->key.objectid + cache->key.offset;
232 wrapped:
233 cache = btrfs_lookup_block_group(root->fs_info, last);
234 if (!cache) {
235 no_cache:
236 if (!wrapped) {
237 wrapped = 1;
238 last = search_start;
239 goto wrapped;
240 }
241 goto out;
242 }
243 if (cache_miss && !cache->cached) {
244 cache_block_group(root, cache);
245 last = cache_miss;
246 cache = btrfs_lookup_block_group(root->fs_info, last);
247 }
248 cache = btrfs_find_block_group(root, cache, last, data, 0);
249 if (!cache)
250 goto no_cache;
251 *cache_ret = cache;
252 cache_miss = 0;
253 goto again;
254 }
255
256 static u64 div_factor(u64 num, int factor)
257 {
258 if (factor == 10)
259 return num;
260 num *= factor;
261 num /= 10;
262 return num;
263 }
264
265 static int block_group_state_bits(u64 flags)
266 {
267 int bits = 0;
268 if (flags & BTRFS_BLOCK_GROUP_DATA)
269 bits |= BLOCK_GROUP_DATA;
270 if (flags & BTRFS_BLOCK_GROUP_METADATA)
271 bits |= BLOCK_GROUP_METADATA;
272 if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
273 bits |= BLOCK_GROUP_SYSTEM;
274 return bits;
275 }
276
277 struct btrfs_block_group_cache *btrfs_find_block_group(struct btrfs_root *root,
278 struct btrfs_block_group_cache
279 *hint, u64 search_start,
280 int data, int owner)
281 {
282 struct btrfs_block_group_cache *cache;
283 struct extent_io_tree *block_group_cache;
284 struct btrfs_block_group_cache *found_group = NULL;
285 struct btrfs_fs_info *info = root->fs_info;
286 u64 used;
287 u64 last = 0;
288 u64 hint_last;
289 u64 start;
290 u64 end;
291 u64 free_check;
292 u64 ptr;
293 int bit;
294 int ret;
295 int full_search = 0;
296 int factor = 10;
297
298 block_group_cache = &info->block_group_cache;
299
300 if (!owner)
301 factor = 10;
302
303 bit = block_group_state_bits(data);
304
305 if (search_start) {
306 struct btrfs_block_group_cache *shint;
307 shint = btrfs_lookup_block_group(info, search_start);
308 if (shint && block_group_bits(shint, data)) {
309 used = btrfs_block_group_used(&shint->item);
310 if (used + shint->pinned <
311 div_factor(shint->key.offset, factor)) {
312 return shint;
313 }
314 }
315 }
316 if (hint && block_group_bits(hint, data)) {
317 used = btrfs_block_group_used(&hint->item);
318 if (used + hint->pinned <
319 div_factor(hint->key.offset, factor)) {
320 return hint;
321 }
322 last = hint->key.objectid + hint->key.offset;
323 hint_last = last;
324 } else {
325 if (hint)
326 hint_last = max(hint->key.objectid, search_start);
327 else
328 hint_last = search_start;
329
330 last = hint_last;
331 }
332 again:
333 while(1) {
334 ret = find_first_extent_bit(block_group_cache, last,
335 &start, &end, bit);
336 if (ret)
337 break;
338
339 ret = get_state_private(block_group_cache, start, &ptr);
340 if (ret)
341 break;
342
343 cache = (struct btrfs_block_group_cache *)(unsigned long)ptr;
344 last = cache->key.objectid + cache->key.offset;
345 used = btrfs_block_group_used(&cache->item);
346
347 if (block_group_bits(cache, data)) {
348 if (full_search)
349 free_check = cache->key.offset;
350 else
351 free_check = div_factor(cache->key.offset,
352 factor);
353
354 if (used + cache->pinned < free_check) {
355 found_group = cache;
356 goto found;
357 }
358 }
359 cond_resched();
360 }
361 if (!full_search) {
362 last = search_start;
363 full_search = 1;
364 goto again;
365 }
366 found:
367 return found_group;
368 }
369
370 static u64 hash_extent_ref(u64 root_objectid, u64 ref_generation,
371 u64 owner, u64 owner_offset)
372 {
373 u32 high_crc = ~(u32)0;
374 u32 low_crc = ~(u32)0;
375 __le64 lenum;
376
377 lenum = cpu_to_le64(root_objectid);
378 high_crc = crc32c(high_crc, &lenum, sizeof(lenum));
379 lenum = cpu_to_le64(ref_generation);
380 low_crc = crc32c(low_crc, &lenum, sizeof(lenum));
381 if (owner >= BTRFS_FIRST_FREE_OBJECTID) {
382 lenum = cpu_to_le64(owner);
383 low_crc = crc32c(low_crc, &lenum, sizeof(lenum));
384 lenum = cpu_to_le64(owner_offset);
385 low_crc = crc32c(low_crc, &lenum, sizeof(lenum));
386 }
387 return ((u64)high_crc << 32) | (u64)low_crc;
388 }
389
390 static int match_extent_ref(struct extent_buffer *leaf,
391 struct btrfs_extent_ref *disk_ref,
392 struct btrfs_extent_ref *cpu_ref)
393 {
394 int ret;
395 int len;
396
397 if (cpu_ref->objectid)
398 len = sizeof(*cpu_ref);
399 else
400 len = 2 * sizeof(u64);
401 ret = memcmp_extent_buffer(leaf, cpu_ref, (unsigned long)disk_ref,
402 len);
403 return ret == 0;
404 }
405
406 static int noinline lookup_extent_backref(struct btrfs_trans_handle *trans,
407 struct btrfs_root *root,
408 struct btrfs_path *path, u64 bytenr,
409 u64 root_objectid,
410 u64 ref_generation, u64 owner,
411 u64 owner_offset, int del)
412 {
413 u64 hash;
414 struct btrfs_key key;
415 struct btrfs_key found_key;
416 struct btrfs_extent_ref ref;
417 struct extent_buffer *leaf;
418 struct btrfs_extent_ref *disk_ref;
419 int ret;
420 int ret2;
421
422 btrfs_set_stack_ref_root(&ref, root_objectid);
423 btrfs_set_stack_ref_generation(&ref, ref_generation);
424 btrfs_set_stack_ref_objectid(&ref, owner);
425 btrfs_set_stack_ref_offset(&ref, owner_offset);
426
427 hash = hash_extent_ref(root_objectid, ref_generation, owner,
428 owner_offset);
429 key.offset = hash;
430 key.objectid = bytenr;
431 key.type = BTRFS_EXTENT_REF_KEY;
432
433 while (1) {
434 ret = btrfs_search_slot(trans, root, &key, path,
435 del ? -1 : 0, del);
436 if (ret < 0)
437 goto out;
438 leaf = path->nodes[0];
439 if (ret != 0) {
440 u32 nritems = btrfs_header_nritems(leaf);
441 if (path->slots[0] >= nritems) {
442 ret2 = btrfs_next_leaf(root, path);
443 if (ret2)
444 goto out;
445 leaf = path->nodes[0];
446 }
447 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
448 if (found_key.objectid != bytenr ||
449 found_key.type != BTRFS_EXTENT_REF_KEY)
450 goto out;
451 key.offset = found_key.offset;
452 if (del) {
453 btrfs_release_path(root, path);
454 continue;
455 }
456 }
457 disk_ref = btrfs_item_ptr(path->nodes[0],
458 path->slots[0],
459 struct btrfs_extent_ref);
460 if (match_extent_ref(path->nodes[0], disk_ref, &ref)) {
461 ret = 0;
462 goto out;
463 }
464 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
465 key.offset = found_key.offset + 1;
466 btrfs_release_path(root, path);
467 }
468 out:
469 return ret;
470 }
471
472 /*
473 * Back reference rules. Back refs have three main goals:
474 *
475 * 1) differentiate between all holders of references to an extent so that
476 * when a reference is dropped we can make sure it was a valid reference
477 * before freeing the extent.
478 *
479 * 2) Provide enough information to quickly find the holders of an extent
480 * if we notice a given block is corrupted or bad.
481 *
482 * 3) Make it easy to migrate blocks for FS shrinking or storage pool
483 * maintenance. This is actually the same as #2, but with a slightly
484 * different use case.
485 *
486 * File extents can be referenced by:
487 *
488 * - multiple snapshots, subvolumes, or different generations in one subvol
489 * - different files inside a single subvolume (in theory, not implemented yet)
490 * - different offsets inside a file (bookend extents in file.c)
491 *
492 * The extent ref structure has fields for:
493 *
494 * - Objectid of the subvolume root
495 * - Generation number of the tree holding the reference
496 * - objectid of the file holding the reference
497 * - offset in the file corresponding to the key holding the reference
498 *
499 * When a file extent is allocated the fields are filled in:
500 * (root_key.objectid, trans->transid, inode objectid, offset in file)
501 *
502 * When a leaf is cow'd new references are added for every file extent found
503 * in the leaf. It looks the same as the create case, but trans->transid
504 * will be different when the block is cow'd.
505 *
506 * (root_key.objectid, trans->transid, inode objectid, offset in file)
507 *
508 * When a file extent is removed either during snapshot deletion or file
509 * truncation, the corresponding back reference is found
510 * by searching for:
511 *
512 * (btrfs_header_owner(leaf), btrfs_header_generation(leaf),
513 * inode objectid, offset in file)
514 *
515 * Btree extents can be referenced by:
516 *
517 * - Different subvolumes
518 * - Different generations of the same subvolume
519 *
520 * Storing sufficient information for a full reverse mapping of a btree
521 * block would require storing the lowest key of the block in the backref,
522 * and it would require updating that lowest key either before write out or
523 * every time it changed. Instead, the objectid of the lowest key is stored
524 * along with the level of the tree block. This provides a hint
525 * about where in the btree the block can be found. Searches through the
526 * btree only need to look for a pointer to that block, so they stop one
527 * level higher than the level recorded in the backref.
528 *
529 * Some btrees do not do reference counting on their extents. These
530 * include the extent tree and the tree of tree roots. Backrefs for these
531 * trees always have a generation of zero.
532 *
533 * When a tree block is created, back references are inserted:
534 *
535 * (root->root_key.objectid, trans->transid or zero, level, lowest_key_objectid)
536 *
537 * When a tree block is cow'd in a reference counted root,
538 * new back references are added for all the blocks it points to.
539 * These are of the form (trans->transid will have increased since creation):
540 *
541 * (root->root_key.objectid, trans->transid, level, lowest_key_objectid)
542 *
543 * Because the lowest_key_objectid and the level are just hints
544 * they are not used when backrefs are deleted. When a backref is deleted:
545 *
546 * if backref was for a tree root:
547 * root_objectid = root->root_key.objectid
548 * else
549 * root_objectid = btrfs_header_owner(parent)
550 *
551 * (root_objectid, btrfs_header_generation(parent) or zero, 0, 0)
552 *
553 * Back Reference Key hashing:
554 *
555 * Back references have four fields, each 64 bits long. Unfortunately,
556 * This is hashed into a single 64 bit number and placed into the key offset.
557 * The key objectid corresponds to the first byte in the extent, and the
558 * key type is set to BTRFS_EXTENT_REF_KEY
559 */
560 int btrfs_insert_extent_backref(struct btrfs_trans_handle *trans,
561 struct btrfs_root *root,
562 struct btrfs_path *path, u64 bytenr,
563 u64 root_objectid, u64 ref_generation,
564 u64 owner, u64 owner_offset)
565 {
566 u64 hash;
567 struct btrfs_key key;
568 struct btrfs_extent_ref ref;
569 struct btrfs_extent_ref *disk_ref;
570 int ret;
571
572 btrfs_set_stack_ref_root(&ref, root_objectid);
573 btrfs_set_stack_ref_generation(&ref, ref_generation);
574 btrfs_set_stack_ref_objectid(&ref, owner);
575 btrfs_set_stack_ref_offset(&ref, owner_offset);
576
577 hash = hash_extent_ref(root_objectid, ref_generation, owner,
578 owner_offset);
579 key.offset = hash;
580 key.objectid = bytenr;
581 key.type = BTRFS_EXTENT_REF_KEY;
582
583 ret = btrfs_insert_empty_item(trans, root, path, &key, sizeof(ref));
584 while (ret == -EEXIST) {
585 disk_ref = btrfs_item_ptr(path->nodes[0], path->slots[0],
586 struct btrfs_extent_ref);
587 if (match_extent_ref(path->nodes[0], disk_ref, &ref))
588 goto out;
589 key.offset++;
590 btrfs_release_path(root, path);
591 ret = btrfs_insert_empty_item(trans, root, path, &key,
592 sizeof(ref));
593 }
594 if (ret)
595 goto out;
596 disk_ref = btrfs_item_ptr(path->nodes[0], path->slots[0],
597 struct btrfs_extent_ref);
598 write_extent_buffer(path->nodes[0], &ref, (unsigned long)disk_ref,
599 sizeof(ref));
600 btrfs_mark_buffer_dirty(path->nodes[0]);
601 out:
602 btrfs_release_path(root, path);
603 return ret;
604 }
605
606 int btrfs_inc_extent_ref(struct btrfs_trans_handle *trans,
607 struct btrfs_root *root,
608 u64 bytenr, u64 num_bytes,
609 u64 root_objectid, u64 ref_generation,
610 u64 owner, u64 owner_offset)
611 {
612 struct btrfs_path *path;
613 int ret;
614 struct btrfs_key key;
615 struct extent_buffer *l;
616 struct btrfs_extent_item *item;
617 u32 refs;
618
619 WARN_ON(num_bytes < root->sectorsize);
620 path = btrfs_alloc_path();
621 if (!path)
622 return -ENOMEM;
623
624 key.objectid = bytenr;
625 btrfs_set_key_type(&key, BTRFS_EXTENT_ITEM_KEY);
626 key.offset = num_bytes;
627 ret = btrfs_search_slot(trans, root->fs_info->extent_root, &key, path,
628 0, 1);
629 if (ret < 0)
630 return ret;
631 if (ret != 0) {
632 BUG();
633 }
634 BUG_ON(ret != 0);
635 l = path->nodes[0];
636 item = btrfs_item_ptr(l, path->slots[0], struct btrfs_extent_item);
637 refs = btrfs_extent_refs(l, item);
638 btrfs_set_extent_refs(l, item, refs + 1);
639 btrfs_mark_buffer_dirty(path->nodes[0]);
640
641 btrfs_release_path(root->fs_info->extent_root, path);
642
643 ret = btrfs_insert_extent_backref(trans, root->fs_info->extent_root,
644 path, bytenr, root_objectid,
645 ref_generation, owner, owner_offset);
646 BUG_ON(ret);
647 finish_current_insert(trans, root->fs_info->extent_root);
648 del_pending_extents(trans, root->fs_info->extent_root);
649
650 btrfs_free_path(path);
651 return 0;
652 }
653
654 int btrfs_extent_post_op(struct btrfs_trans_handle *trans,
655 struct btrfs_root *root)
656 {
657 finish_current_insert(trans, root->fs_info->extent_root);
658 del_pending_extents(trans, root->fs_info->extent_root);
659 return 0;
660 }
661
662 static int lookup_extent_ref(struct btrfs_trans_handle *trans,
663 struct btrfs_root *root, u64 bytenr,
664 u64 num_bytes, u32 *refs)
665 {
666 struct btrfs_path *path;
667 int ret;
668 struct btrfs_key key;
669 struct extent_buffer *l;
670 struct btrfs_extent_item *item;
671
672 WARN_ON(num_bytes < root->sectorsize);
673 path = btrfs_alloc_path();
674 key.objectid = bytenr;
675 key.offset = num_bytes;
676 btrfs_set_key_type(&key, BTRFS_EXTENT_ITEM_KEY);
677 ret = btrfs_search_slot(trans, root->fs_info->extent_root, &key, path,
678 0, 0);
679 if (ret < 0)
680 goto out;
681 if (ret != 0) {
682 btrfs_print_leaf(root, path->nodes[0]);
683 printk("failed to find block number %llu\n",
684 (unsigned long long)bytenr);
685 BUG();
686 }
687 l = path->nodes[0];
688 item = btrfs_item_ptr(l, path->slots[0], struct btrfs_extent_item);
689 *refs = btrfs_extent_refs(l, item);
690 out:
691 btrfs_free_path(path);
692 return 0;
693 }
694
695 u32 btrfs_count_snapshots_in_path(struct btrfs_root *root,
696 struct btrfs_path *count_path,
697 u64 first_extent)
698 {
699 struct btrfs_root *extent_root = root->fs_info->extent_root;
700 struct btrfs_path *path;
701 u64 bytenr;
702 u64 found_objectid;
703 u64 root_objectid = root->root_key.objectid;
704 u32 total_count = 0;
705 u32 cur_count;
706 u32 refs;
707 u32 nritems;
708 int ret;
709 struct btrfs_key key;
710 struct btrfs_key found_key;
711 struct extent_buffer *l;
712 struct btrfs_extent_item *item;
713 struct btrfs_extent_ref *ref_item;
714 int level = -1;
715
716 path = btrfs_alloc_path();
717 again:
718 if (level == -1)
719 bytenr = first_extent;
720 else
721 bytenr = count_path->nodes[level]->start;
722
723 cur_count = 0;
724 key.objectid = bytenr;
725 key.offset = 0;
726
727 btrfs_set_key_type(&key, BTRFS_EXTENT_ITEM_KEY);
728 ret = btrfs_search_slot(NULL, extent_root, &key, path, 0, 0);
729 if (ret < 0)
730 goto out;
731 BUG_ON(ret == 0);
732
733 l = path->nodes[0];
734 btrfs_item_key_to_cpu(l, &found_key, path->slots[0]);
735
736 if (found_key.objectid != bytenr ||
737 found_key.type != BTRFS_EXTENT_ITEM_KEY) {
738 goto out;
739 }
740
741 item = btrfs_item_ptr(l, path->slots[0], struct btrfs_extent_item);
742 refs = btrfs_extent_refs(l, item);
743 while (1) {
744 nritems = btrfs_header_nritems(l);
745 if (path->slots[0] >= nritems) {
746 ret = btrfs_next_leaf(extent_root, path);
747 if (ret == 0)
748 continue;
749 break;
750 }
751 btrfs_item_key_to_cpu(l, &found_key, path->slots[0]);
752 if (found_key.objectid != bytenr)
753 break;
754 if (found_key.type != BTRFS_EXTENT_REF_KEY) {
755 path->slots[0]++;
756 continue;
757 }
758
759 cur_count++;
760 ref_item = btrfs_item_ptr(l, path->slots[0],
761 struct btrfs_extent_ref);
762 found_objectid = btrfs_ref_root(l, ref_item);
763
764 if (found_objectid != root_objectid) {
765 total_count = 2;
766 goto out;
767 }
768 total_count = 1;
769 path->slots[0]++;
770 }
771 if (cur_count == 0) {
772 total_count = 0;
773 goto out;
774 }
775 if (level >= 0 && root->node == count_path->nodes[level])
776 goto out;
777 level++;
778 btrfs_release_path(root, path);
779 goto again;
780
781 out:
782 btrfs_free_path(path);
783 return total_count;
784 }
785 int btrfs_inc_root_ref(struct btrfs_trans_handle *trans,
786 struct btrfs_root *root, u64 owner_objectid)
787 {
788 u64 generation;
789 u64 key_objectid;
790 u64 level;
791 u32 nritems;
792 struct btrfs_disk_key disk_key;
793
794 level = btrfs_header_level(root->node);
795 generation = trans->transid;
796 nritems = btrfs_header_nritems(root->node);
797 if (nritems > 0) {
798 if (level == 0)
799 btrfs_item_key(root->node, &disk_key, 0);
800 else
801 btrfs_node_key(root->node, &disk_key, 0);
802 key_objectid = btrfs_disk_key_objectid(&disk_key);
803 } else {
804 key_objectid = 0;
805 }
806 return btrfs_inc_extent_ref(trans, root, root->node->start,
807 root->node->len, owner_objectid,
808 generation, level, key_objectid);
809 }
810
811 int btrfs_inc_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root,
812 struct extent_buffer *buf)
813 {
814 u64 bytenr;
815 u32 nritems;
816 struct btrfs_key key;
817 struct btrfs_file_extent_item *fi;
818 int i;
819 int level;
820 int ret;
821 int faili;
822
823 if (!root->ref_cows)
824 return 0;
825
826 level = btrfs_header_level(buf);
827 nritems = btrfs_header_nritems(buf);
828 for (i = 0; i < nritems; i++) {
829 if (level == 0) {
830 u64 disk_bytenr;
831 btrfs_item_key_to_cpu(buf, &key, i);
832 if (btrfs_key_type(&key) != BTRFS_EXTENT_DATA_KEY)
833 continue;
834 fi = btrfs_item_ptr(buf, i,
835 struct btrfs_file_extent_item);
836 if (btrfs_file_extent_type(buf, fi) ==
837 BTRFS_FILE_EXTENT_INLINE)
838 continue;
839 disk_bytenr = btrfs_file_extent_disk_bytenr(buf, fi);
840 if (disk_bytenr == 0)
841 continue;
842 ret = btrfs_inc_extent_ref(trans, root, disk_bytenr,
843 btrfs_file_extent_disk_num_bytes(buf, fi),
844 root->root_key.objectid, trans->transid,
845 key.objectid, key.offset);
846 if (ret) {
847 faili = i;
848 goto fail;
849 }
850 } else {
851 bytenr = btrfs_node_blockptr(buf, i);
852 btrfs_node_key_to_cpu(buf, &key, i);
853 ret = btrfs_inc_extent_ref(trans, root, bytenr,
854 btrfs_level_size(root, level - 1),
855 root->root_key.objectid,
856 trans->transid,
857 level - 1, key.objectid);
858 if (ret) {
859 faili = i;
860 goto fail;
861 }
862 }
863 }
864 return 0;
865 fail:
866 WARN_ON(1);
867 #if 0
868 for (i =0; i < faili; i++) {
869 if (level == 0) {
870 u64 disk_bytenr;
871 btrfs_item_key_to_cpu(buf, &key, i);
872 if (btrfs_key_type(&key) != BTRFS_EXTENT_DATA_KEY)
873 continue;
874 fi = btrfs_item_ptr(buf, i,
875 struct btrfs_file_extent_item);
876 if (btrfs_file_extent_type(buf, fi) ==
877 BTRFS_FILE_EXTENT_INLINE)
878 continue;
879 disk_bytenr = btrfs_file_extent_disk_bytenr(buf, fi);
880 if (disk_bytenr == 0)
881 continue;
882 err = btrfs_free_extent(trans, root, disk_bytenr,
883 btrfs_file_extent_disk_num_bytes(buf,
884 fi), 0);
885 BUG_ON(err);
886 } else {
887 bytenr = btrfs_node_blockptr(buf, i);
888 err = btrfs_free_extent(trans, root, bytenr,
889 btrfs_level_size(root, level - 1), 0);
890 BUG_ON(err);
891 }
892 }
893 #endif
894 return ret;
895 }
896
897 static int write_one_cache_group(struct btrfs_trans_handle *trans,
898 struct btrfs_root *root,
899 struct btrfs_path *path,
900 struct btrfs_block_group_cache *cache)
901 {
902 int ret;
903 int pending_ret;
904 struct btrfs_root *extent_root = root->fs_info->extent_root;
905 unsigned long bi;
906 struct extent_buffer *leaf;
907
908 ret = btrfs_search_slot(trans, extent_root, &cache->key, path, 0, 1);
909 if (ret < 0)
910 goto fail;
911 BUG_ON(ret);
912
913 leaf = path->nodes[0];
914 bi = btrfs_item_ptr_offset(leaf, path->slots[0]);
915 write_extent_buffer(leaf, &cache->item, bi, sizeof(cache->item));
916 btrfs_mark_buffer_dirty(leaf);
917 btrfs_release_path(extent_root, path);
918 fail:
919 finish_current_insert(trans, extent_root);
920 pending_ret = del_pending_extents(trans, extent_root);
921 if (ret)
922 return ret;
923 if (pending_ret)
924 return pending_ret;
925 return 0;
926
927 }
928
929 int btrfs_write_dirty_block_groups(struct btrfs_trans_handle *trans,
930 struct btrfs_root *root)
931 {
932 struct extent_io_tree *block_group_cache;
933 struct btrfs_block_group_cache *cache;
934 int ret;
935 int err = 0;
936 int werr = 0;
937 struct btrfs_path *path;
938 u64 last = 0;
939 u64 start;
940 u64 end;
941 u64 ptr;
942
943 block_group_cache = &root->fs_info->block_group_cache;
944 path = btrfs_alloc_path();
945 if (!path)
946 return -ENOMEM;
947
948 while(1) {
949 ret = find_first_extent_bit(block_group_cache, last,
950 &start, &end, BLOCK_GROUP_DIRTY);
951 if (ret)
952 break;
953
954 last = end + 1;
955 ret = get_state_private(block_group_cache, start, &ptr);
956 if (ret)
957 break;
958 cache = (struct btrfs_block_group_cache *)(unsigned long)ptr;
959 err = write_one_cache_group(trans, root,
960 path, cache);
961 /*
962 * if we fail to write the cache group, we want
963 * to keep it marked dirty in hopes that a later
964 * write will work
965 */
966 if (err) {
967 werr = err;
968 continue;
969 }
970 clear_extent_bits(block_group_cache, start, end,
971 BLOCK_GROUP_DIRTY, GFP_NOFS);
972 }
973 btrfs_free_path(path);
974 return werr;
975 }
976
977 static struct btrfs_space_info *__find_space_info(struct btrfs_fs_info *info,
978 u64 flags)
979 {
980 struct list_head *head = &info->space_info;
981 struct list_head *cur;
982 struct btrfs_space_info *found;
983 list_for_each(cur, head) {
984 found = list_entry(cur, struct btrfs_space_info, list);
985 if (found->flags == flags)
986 return found;
987 }
988 return NULL;
989
990 }
991
992 static int update_space_info(struct btrfs_fs_info *info, u64 flags,
993 u64 total_bytes, u64 bytes_used,
994 struct btrfs_space_info **space_info)
995 {
996 struct btrfs_space_info *found;
997
998 found = __find_space_info(info, flags);
999 if (found) {
1000 found->total_bytes += total_bytes;
1001 found->bytes_used += bytes_used;
1002 WARN_ON(found->total_bytes < found->bytes_used);
1003 *space_info = found;
1004 return 0;
1005 }
1006 found = kmalloc(sizeof(*found), GFP_NOFS);
1007 if (!found)
1008 return -ENOMEM;
1009
1010 list_add(&found->list, &info->space_info);
1011 found->flags = flags;
1012 found->total_bytes = total_bytes;
1013 found->bytes_used = bytes_used;
1014 found->bytes_pinned = 0;
1015 found->full = 0;
1016 *space_info = found;
1017 return 0;
1018 }
1019
1020
1021 static void set_avail_alloc_bits(struct btrfs_fs_info *fs_info, u64 flags)
1022 {
1023 u64 extra_flags = flags & (BTRFS_BLOCK_GROUP_RAID0 |
1024 BTRFS_BLOCK_GROUP_RAID1 |
1025 BTRFS_BLOCK_GROUP_DUP);
1026 if (extra_flags) {
1027 if (flags & BTRFS_BLOCK_GROUP_DATA)
1028 fs_info->avail_data_alloc_bits |= extra_flags;
1029 if (flags & BTRFS_BLOCK_GROUP_METADATA)
1030 fs_info->avail_metadata_alloc_bits |= extra_flags;
1031 if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
1032 fs_info->avail_system_alloc_bits |= extra_flags;
1033 }
1034 }
1035
1036 static int do_chunk_alloc(struct btrfs_trans_handle *trans,
1037 struct btrfs_root *extent_root, u64 alloc_bytes,
1038 u64 flags)
1039 {
1040 struct btrfs_space_info *space_info;
1041 u64 thresh;
1042 u64 start;
1043 u64 num_bytes;
1044 int ret;
1045
1046 space_info = __find_space_info(extent_root->fs_info, flags);
1047 if (!space_info) {
1048 ret = update_space_info(extent_root->fs_info, flags,
1049 0, 0, &space_info);
1050 BUG_ON(ret);
1051 }
1052 BUG_ON(!space_info);
1053
1054 if (space_info->full)
1055 return 0;
1056
1057 thresh = div_factor(space_info->total_bytes, 7);
1058 if ((space_info->bytes_used + space_info->bytes_pinned + alloc_bytes) <
1059 thresh)
1060 return 0;
1061
1062 ret = btrfs_alloc_chunk(trans, extent_root, &start, &num_bytes, flags);
1063 if (ret == -ENOSPC) {
1064 space_info->full = 1;
1065 return 0;
1066 }
1067
1068 BUG_ON(ret);
1069
1070 ret = btrfs_make_block_group(trans, extent_root, 0, flags,
1071 BTRFS_FIRST_CHUNK_TREE_OBJECTID, start, num_bytes);
1072 BUG_ON(ret);
1073 return 0;
1074 }
1075
1076 static int update_block_group(struct btrfs_trans_handle *trans,
1077 struct btrfs_root *root,
1078 u64 bytenr, u64 num_bytes, int alloc,
1079 int mark_free)
1080 {
1081 struct btrfs_block_group_cache *cache;
1082 struct btrfs_fs_info *info = root->fs_info;
1083 u64 total = num_bytes;
1084 u64 old_val;
1085 u64 byte_in_group;
1086 u64 start;
1087 u64 end;
1088
1089 while(total) {
1090 cache = btrfs_lookup_block_group(info, bytenr);
1091 if (!cache) {
1092 return -1;
1093 }
1094 byte_in_group = bytenr - cache->key.objectid;
1095 WARN_ON(byte_in_group > cache->key.offset);
1096 start = cache->key.objectid;
1097 end = start + cache->key.offset - 1;
1098 set_extent_bits(&info->block_group_cache, start, end,
1099 BLOCK_GROUP_DIRTY, GFP_NOFS);
1100
1101 old_val = btrfs_block_group_used(&cache->item);
1102 num_bytes = min(total, cache->key.offset - byte_in_group);
1103 if (alloc) {
1104 old_val += num_bytes;
1105 cache->space_info->bytes_used += num_bytes;
1106 } else {
1107 old_val -= num_bytes;
1108 cache->space_info->bytes_used -= num_bytes;
1109 if (mark_free) {
1110 set_extent_dirty(&info->free_space_cache,
1111 bytenr, bytenr + num_bytes - 1,
1112 GFP_NOFS);
1113 }
1114 }
1115 btrfs_set_block_group_used(&cache->item, old_val);
1116 total -= num_bytes;
1117 bytenr += num_bytes;
1118 }
1119 return 0;
1120 }
1121
1122 static int update_pinned_extents(struct btrfs_root *root,
1123 u64 bytenr, u64 num, int pin)
1124 {
1125 u64 len;
1126 struct btrfs_block_group_cache *cache;
1127 struct btrfs_fs_info *fs_info = root->fs_info;
1128
1129 if (pin) {
1130 set_extent_dirty(&fs_info->pinned_extents,
1131 bytenr, bytenr + num - 1, GFP_NOFS);
1132 } else {
1133 clear_extent_dirty(&fs_info->pinned_extents,
1134 bytenr, bytenr + num - 1, GFP_NOFS);
1135 }
1136 while (num > 0) {
1137 cache = btrfs_lookup_block_group(fs_info, bytenr);
1138 WARN_ON(!cache);
1139 len = min(num, cache->key.offset -
1140 (bytenr - cache->key.objectid));
1141 if (pin) {
1142 cache->pinned += len;
1143 cache->space_info->bytes_pinned += len;
1144 fs_info->total_pinned += len;
1145 } else {
1146 cache->pinned -= len;
1147 cache->space_info->bytes_pinned -= len;
1148 fs_info->total_pinned -= len;
1149 }
1150 bytenr += len;
1151 num -= len;
1152 }
1153 return 0;
1154 }
1155
1156 int btrfs_copy_pinned(struct btrfs_root *root, struct extent_io_tree *copy)
1157 {
1158 u64 last = 0;
1159 u64 start;
1160 u64 end;
1161 struct extent_io_tree *pinned_extents = &root->fs_info->pinned_extents;
1162 int ret;
1163
1164 while(1) {
1165 ret = find_first_extent_bit(pinned_extents, last,
1166 &start, &end, EXTENT_DIRTY);
1167 if (ret)
1168 break;
1169 set_extent_dirty(copy, start, end, GFP_NOFS);
1170 last = end + 1;
1171 }
1172 return 0;
1173 }
1174
1175 int btrfs_finish_extent_commit(struct btrfs_trans_handle *trans,
1176 struct btrfs_root *root,
1177 struct extent_io_tree *unpin)
1178 {
1179 u64 start;
1180 u64 end;
1181 int ret;
1182 struct extent_io_tree *free_space_cache;
1183 free_space_cache = &root->fs_info->free_space_cache;
1184
1185 while(1) {
1186 ret = find_first_extent_bit(unpin, 0, &start, &end,
1187 EXTENT_DIRTY);
1188 if (ret)
1189 break;
1190 update_pinned_extents(root, start, end + 1 - start, 0);
1191 clear_extent_dirty(unpin, start, end, GFP_NOFS);
1192 set_extent_dirty(free_space_cache, start, end, GFP_NOFS);
1193 }
1194 return 0;
1195 }
1196
1197 static int finish_current_insert(struct btrfs_trans_handle *trans,
1198 struct btrfs_root *extent_root)
1199 {
1200 u64 start;
1201 u64 end;
1202 struct btrfs_fs_info *info = extent_root->fs_info;
1203 struct extent_buffer *eb;
1204 struct btrfs_path *path;
1205 struct btrfs_key ins;
1206 struct btrfs_disk_key first;
1207 struct btrfs_extent_item extent_item;
1208 int ret;
1209 int level;
1210 int err = 0;
1211
1212 btrfs_set_stack_extent_refs(&extent_item, 1);
1213 btrfs_set_key_type(&ins, BTRFS_EXTENT_ITEM_KEY);
1214 path = btrfs_alloc_path();
1215
1216 while(1) {
1217 ret = find_first_extent_bit(&info->extent_ins, 0, &start,
1218 &end, EXTENT_LOCKED);
1219 if (ret)
1220 break;
1221
1222 ins.objectid = start;
1223 ins.offset = end + 1 - start;
1224 err = btrfs_insert_item(trans, extent_root, &ins,
1225 &extent_item, sizeof(extent_item));
1226 clear_extent_bits(&info->extent_ins, start, end, EXTENT_LOCKED,
1227 GFP_NOFS);
1228 eb = read_tree_block(extent_root, ins.objectid, ins.offset,
1229 trans->transid);
1230 level = btrfs_header_level(eb);
1231 if (level == 0) {
1232 btrfs_item_key(eb, &first, 0);
1233 } else {
1234 btrfs_node_key(eb, &first, 0);
1235 }
1236 err = btrfs_insert_extent_backref(trans, extent_root, path,
1237 start, extent_root->root_key.objectid,
1238 0, level,
1239 btrfs_disk_key_objectid(&first));
1240 BUG_ON(err);
1241 free_extent_buffer(eb);
1242 }
1243 btrfs_free_path(path);
1244 return 0;
1245 }
1246
1247 static int pin_down_bytes(struct btrfs_root *root, u64 bytenr, u32 num_bytes,
1248 int pending)
1249 {
1250 int err = 0;
1251 struct extent_buffer *buf;
1252
1253 if (!pending) {
1254 buf = btrfs_find_tree_block(root, bytenr, num_bytes);
1255 if (buf) {
1256 if (btrfs_buffer_uptodate(buf, 0)) {
1257 u64 transid =
1258 root->fs_info->running_transaction->transid;
1259 if (btrfs_header_generation(buf) ==
1260 transid && !btrfs_header_flag(buf,
1261 BTRFS_HEADER_FLAG_WRITTEN)) {
1262 free_extent_buffer(buf);
1263 return 1;
1264 }
1265 }
1266 free_extent_buffer(buf);
1267 }
1268 update_pinned_extents(root, bytenr, num_bytes, 1);
1269 } else {
1270 set_extent_bits(&root->fs_info->pending_del,
1271 bytenr, bytenr + num_bytes - 1,
1272 EXTENT_LOCKED, GFP_NOFS);
1273 }
1274 BUG_ON(err < 0);
1275 return 0;
1276 }
1277
1278 /*
1279 * remove an extent from the root, returns 0 on success
1280 */
1281 static int __free_extent(struct btrfs_trans_handle *trans, struct btrfs_root
1282 *root, u64 bytenr, u64 num_bytes,
1283 u64 root_objectid, u64 ref_generation,
1284 u64 owner_objectid, u64 owner_offset, int pin,
1285 int mark_free)
1286 {
1287 struct btrfs_path *path;
1288 struct btrfs_key key;
1289 struct btrfs_fs_info *info = root->fs_info;
1290 struct btrfs_extent_ops *ops = info->extent_ops;
1291 struct btrfs_root *extent_root = info->extent_root;
1292 struct extent_buffer *leaf;
1293 int ret;
1294 int extent_slot = 0;
1295 int found_extent = 0;
1296 int num_to_del = 1;
1297 struct btrfs_extent_item *ei;
1298 u32 refs;
1299
1300 key.objectid = bytenr;
1301 btrfs_set_key_type(&key, BTRFS_EXTENT_ITEM_KEY);
1302 key.offset = num_bytes;
1303
1304 path = btrfs_alloc_path();
1305 if (!path)
1306 return -ENOMEM;
1307
1308 ret = lookup_extent_backref(trans, extent_root, path,
1309 bytenr, root_objectid,
1310 ref_generation,
1311 owner_objectid, owner_offset, 1);
1312 if (ret == 0) {
1313 struct btrfs_key found_key;
1314 extent_slot = path->slots[0];
1315 while(extent_slot > 0) {
1316 extent_slot--;
1317 btrfs_item_key_to_cpu(path->nodes[0], &found_key,
1318 extent_slot);
1319 if (found_key.objectid != bytenr)
1320 break;
1321 if (found_key.type == BTRFS_EXTENT_ITEM_KEY &&
1322 found_key.offset == num_bytes) {
1323 found_extent = 1;
1324 break;
1325 }
1326 if (path->slots[0] - extent_slot > 5)
1327 break;
1328 }
1329 if (!found_extent)
1330 ret = btrfs_del_item(trans, extent_root, path);
1331 } else {
1332 btrfs_print_leaf(extent_root, path->nodes[0]);
1333 WARN_ON(1);
1334 printk("Unable to find ref byte nr %llu root %llu "
1335 " gen %llu owner %llu offset %llu\n",
1336 (unsigned long long)bytenr,
1337 (unsigned long long)root_objectid,
1338 (unsigned long long)ref_generation,
1339 (unsigned long long)owner_objectid,
1340 (unsigned long long)owner_offset);
1341 }
1342 if (!found_extent) {
1343 btrfs_release_path(extent_root, path);
1344 ret = btrfs_search_slot(trans, extent_root, &key, path, -1, 1);
1345 if (ret < 0)
1346 return ret;
1347 BUG_ON(ret);
1348 extent_slot = path->slots[0];
1349 }
1350
1351 leaf = path->nodes[0];
1352 ei = btrfs_item_ptr(leaf, extent_slot,
1353 struct btrfs_extent_item);
1354 refs = btrfs_extent_refs(leaf, ei);
1355 BUG_ON(refs == 0);
1356 refs -= 1;
1357 btrfs_set_extent_refs(leaf, ei, refs);
1358
1359 btrfs_mark_buffer_dirty(leaf);
1360
1361 if (refs == 0 && found_extent && path->slots[0] == extent_slot + 1) {
1362 /* if the back ref and the extent are next to each other
1363 * they get deleted below in one shot
1364 */
1365 path->slots[0] = extent_slot;
1366 num_to_del = 2;
1367 } else if (found_extent) {
1368 /* otherwise delete the extent back ref */
1369 ret = btrfs_del_item(trans, extent_root, path);
1370 BUG_ON(ret);
1371 /* if refs are 0, we need to setup the path for deletion */
1372 if (refs == 0) {
1373 btrfs_release_path(extent_root, path);
1374 ret = btrfs_search_slot(trans, extent_root, &key, path,
1375 -1, 1);
1376 if (ret < 0)
1377 return ret;
1378 BUG_ON(ret);
1379 }
1380 }
1381
1382 if (refs == 0) {
1383 u64 super_used;
1384 u64 root_used;
1385
1386 if (pin) {
1387 ret = pin_down_bytes(root, bytenr, num_bytes, 0);
1388 if (ret > 0)
1389 mark_free = 1;
1390 BUG_ON(ret < 0);
1391 }
1392
1393 /* block accounting for super block */
1394 super_used = btrfs_super_bytes_used(&info->super_copy);
1395 btrfs_set_super_bytes_used(&info->super_copy,
1396 super_used - num_bytes);
1397
1398 /* block accounting for root item */
1399 root_used = btrfs_root_used(&root->root_item);
1400 btrfs_set_root_used(&root->root_item,
1401 root_used - num_bytes);
1402 ret = btrfs_del_items(trans, extent_root, path, path->slots[0],
1403 num_to_del);
1404 if (ret)
1405 return ret;
1406
1407 if (ops && ops->free_extent)
1408 ops->free_extent(root, bytenr, num_bytes);
1409
1410 ret = update_block_group(trans, root, bytenr, num_bytes, 0,
1411 mark_free);
1412 BUG_ON(ret);
1413 }
1414 btrfs_free_path(path);
1415 finish_current_insert(trans, extent_root);
1416 return ret;
1417 }
1418
1419 /*
1420 * find all the blocks marked as pending in the radix tree and remove
1421 * them from the extent map
1422 */
1423 static int del_pending_extents(struct btrfs_trans_handle *trans, struct
1424 btrfs_root *extent_root)
1425 {
1426 int ret;
1427 int err = 0;
1428 u64 start;
1429 u64 end;
1430 struct extent_io_tree *pending_del;
1431 struct extent_io_tree *pinned_extents;
1432
1433 pending_del = &extent_root->fs_info->pending_del;
1434 pinned_extents = &extent_root->fs_info->pinned_extents;
1435
1436 while(1) {
1437 ret = find_first_extent_bit(pending_del, 0, &start, &end,
1438 EXTENT_LOCKED);
1439 if (ret)
1440 break;
1441 update_pinned_extents(extent_root, start, end + 1 - start, 1);
1442 clear_extent_bits(pending_del, start, end, EXTENT_LOCKED,
1443 GFP_NOFS);
1444 ret = __free_extent(trans, extent_root,
1445 start, end + 1 - start,
1446 extent_root->root_key.objectid,
1447 0, 0, 0, 0, 0);
1448 if (ret)
1449 err = ret;
1450 }
1451 return err;
1452 }
1453
1454 /*
1455 * remove an extent from the root, returns 0 on success
1456 */
1457 int btrfs_free_extent(struct btrfs_trans_handle *trans, struct btrfs_root
1458 *root, u64 bytenr, u64 num_bytes,
1459 u64 root_objectid, u64 ref_generation,
1460 u64 owner_objectid, u64 owner_offset, int pin)
1461 {
1462 struct btrfs_root *extent_root = root->fs_info->extent_root;
1463 int pending_ret;
1464 int ret;
1465
1466 WARN_ON(num_bytes < root->sectorsize);
1467 if (!root->ref_cows)
1468 ref_generation = 0;
1469
1470 if (root == extent_root) {
1471 pin_down_bytes(root, bytenr, num_bytes, 1);
1472 return 0;
1473 }
1474 ret = __free_extent(trans, root, bytenr, num_bytes, root_objectid,
1475 ref_generation, owner_objectid, owner_offset,
1476 pin, pin == 0);
1477 pending_ret = del_pending_extents(trans, root->fs_info->extent_root);
1478 return ret ? ret : pending_ret;
1479 }
1480
1481 static u64 stripe_align(struct btrfs_root *root, u64 val)
1482 {
1483 u64 mask = ((u64)root->stripesize - 1);
1484 u64 ret = (val + mask) & ~mask;
1485 return ret;
1486 }
1487
1488 /*
1489 * walks the btree of allocated extents and find a hole of a given size.
1490 * The key ins is changed to record the hole:
1491 * ins->objectid == block start
1492 * ins->flags = BTRFS_EXTENT_ITEM_KEY
1493 * ins->offset == number of blocks
1494 * Any available blocks before search_start are skipped.
1495 */
1496 static int noinline find_free_extent(struct btrfs_trans_handle *trans,
1497 struct btrfs_root *orig_root,
1498 u64 num_bytes, u64 empty_size,
1499 u64 search_start, u64 search_end,
1500 u64 hint_byte, struct btrfs_key *ins,
1501 u64 exclude_start, u64 exclude_nr,
1502 int data)
1503 {
1504 int ret;
1505 u64 orig_search_start = search_start;
1506 struct btrfs_root * root = orig_root->fs_info->extent_root;
1507 struct btrfs_fs_info *info = root->fs_info;
1508 u64 total_needed = num_bytes;
1509 struct btrfs_block_group_cache *block_group;
1510 int full_scan = 0;
1511 int wrapped = 0;
1512
1513 WARN_ON(num_bytes < root->sectorsize);
1514 btrfs_set_key_type(ins, BTRFS_EXTENT_ITEM_KEY);
1515
1516 if (search_end == (u64)-1)
1517 search_end = btrfs_super_total_bytes(&info->super_copy);
1518
1519 if (hint_byte) {
1520 block_group = btrfs_lookup_block_group(info, hint_byte);
1521 if (!block_group)
1522 hint_byte = search_start;
1523 block_group = btrfs_find_block_group(root, block_group,
1524 hint_byte, data, 1);
1525 } else {
1526 block_group = btrfs_find_block_group(root,
1527 trans->block_group,
1528 search_start, data, 1);
1529 }
1530
1531 total_needed += empty_size;
1532
1533 check_failed:
1534 if (!block_group) {
1535 block_group = btrfs_lookup_block_group(info, search_start);
1536 if (!block_group)
1537 block_group = btrfs_lookup_block_group(info,
1538 orig_search_start);
1539 }
1540 ret = find_search_start(root, &block_group, &search_start,
1541 total_needed, data);
1542 if (ret)
1543 goto error;
1544
1545 search_start = stripe_align(root, search_start);
1546 ins->objectid = search_start;
1547 ins->offset = num_bytes;
1548
1549 if (ins->objectid + num_bytes >= search_end)
1550 goto enospc;
1551
1552 if (ins->objectid + num_bytes >
1553 block_group->key.objectid + block_group->key.offset) {
1554 search_start = block_group->key.objectid +
1555 block_group->key.offset;
1556 goto new_group;
1557 }
1558
1559 if (test_range_bit(&info->extent_ins, ins->objectid,
1560 ins->objectid + num_bytes -1, EXTENT_LOCKED, 0)) {
1561 search_start = ins->objectid + num_bytes;
1562 goto new_group;
1563 }
1564
1565 if (test_range_bit(&info->pinned_extents, ins->objectid,
1566 ins->objectid + num_bytes -1, EXTENT_DIRTY, 0)) {
1567 search_start = ins->objectid + num_bytes;
1568 goto new_group;
1569 }
1570
1571 if (exclude_nr > 0 && (ins->objectid + num_bytes > exclude_start &&
1572 ins->objectid < exclude_start + exclude_nr)) {
1573 search_start = exclude_start + exclude_nr;
1574 goto new_group;
1575 }
1576
1577 if (!(data & BTRFS_BLOCK_GROUP_DATA)) {
1578 block_group = btrfs_lookup_block_group(info, ins->objectid);
1579 if (block_group)
1580 trans->block_group = block_group;
1581 }
1582 ins->offset = num_bytes;
1583 return 0;
1584
1585 new_group:
1586 if (search_start + num_bytes >= search_end) {
1587 enospc:
1588 search_start = orig_search_start;
1589 if (full_scan) {
1590 ret = -ENOSPC;
1591 goto error;
1592 }
1593 if (wrapped) {
1594 if (!full_scan)
1595 total_needed -= empty_size;
1596 full_scan = 1;
1597 } else
1598 wrapped = 1;
1599 }
1600 block_group = btrfs_lookup_block_group(info, search_start);
1601 cond_resched();
1602 block_group = btrfs_find_block_group(root, block_group,
1603 search_start, data, 0);
1604 goto check_failed;
1605
1606 error:
1607 return ret;
1608 }
1609 /*
1610 * finds a free extent and does all the dirty work required for allocation
1611 * returns the key for the extent through ins, and a tree buffer for
1612 * the first block of the extent through buf.
1613 *
1614 * returns 0 if everything worked, non-zero otherwise.
1615 */
1616 int btrfs_alloc_extent(struct btrfs_trans_handle *trans,
1617 struct btrfs_root *root,
1618 u64 num_bytes, u64 root_objectid, u64 ref_generation,
1619 u64 owner, u64 owner_offset,
1620 u64 empty_size, u64 hint_byte,
1621 u64 search_end, struct btrfs_key *ins, int data)
1622 {
1623 int ret;
1624 int pending_ret;
1625 u64 super_used, root_used;
1626 u64 search_start = 0;
1627 u64 alloc_profile;
1628 u32 sizes[2];
1629 struct btrfs_fs_info *info = root->fs_info;
1630 struct btrfs_root *extent_root = info->extent_root;
1631 struct btrfs_path *path;
1632 struct btrfs_extent_item *extent_item;
1633 struct btrfs_extent_ref *ref;
1634 struct btrfs_key keys[2];
1635
1636 if (info->extent_ops) {
1637 struct btrfs_extent_ops *ops = info->extent_ops;
1638 ret = ops->alloc_extent(root, num_bytes, hint_byte, ins);
1639 BUG_ON(ret);
1640 goto found;
1641 }
1642
1643 if (data) {
1644 alloc_profile = info->avail_data_alloc_bits &
1645 info->data_alloc_profile;
1646 data = BTRFS_BLOCK_GROUP_DATA | alloc_profile;
1647 } else if ((info->system_allocs > 0 || root == info->chunk_root) &&
1648 info->system_allocs >= 0) {
1649 alloc_profile = info->avail_system_alloc_bits &
1650 info->system_alloc_profile;
1651 data = BTRFS_BLOCK_GROUP_SYSTEM | alloc_profile;
1652 } else {
1653 alloc_profile = info->avail_metadata_alloc_bits &
1654 info->metadata_alloc_profile;
1655 data = BTRFS_BLOCK_GROUP_METADATA | alloc_profile;
1656 }
1657
1658 if (root->ref_cows) {
1659 if (!(data & BTRFS_BLOCK_GROUP_METADATA)) {
1660 ret = do_chunk_alloc(trans, root->fs_info->extent_root,
1661 num_bytes,
1662 BTRFS_BLOCK_GROUP_METADATA);
1663 BUG_ON(ret);
1664 }
1665 ret = do_chunk_alloc(trans, root->fs_info->extent_root,
1666 num_bytes + 2 * 1024 * 1024, data);
1667 BUG_ON(ret);
1668 }
1669
1670 WARN_ON(num_bytes < root->sectorsize);
1671 ret = find_free_extent(trans, root, num_bytes, empty_size,
1672 search_start, search_end, hint_byte, ins,
1673 trans->alloc_exclude_start,
1674 trans->alloc_exclude_nr, data);
1675 BUG_ON(ret);
1676 found:
1677 if (ret)
1678 return ret;
1679
1680 /* block accounting for super block */
1681 super_used = btrfs_super_bytes_used(&info->super_copy);
1682 btrfs_set_super_bytes_used(&info->super_copy, super_used + num_bytes);
1683
1684 /* block accounting for root item */
1685 root_used = btrfs_root_used(&root->root_item);
1686 btrfs_set_root_used(&root->root_item, root_used + num_bytes);
1687
1688 clear_extent_dirty(&root->fs_info->free_space_cache,
1689 ins->objectid, ins->objectid + ins->offset - 1,
1690 GFP_NOFS);
1691
1692 if (root == extent_root) {
1693 set_extent_bits(&root->fs_info->extent_ins, ins->objectid,
1694 ins->objectid + ins->offset - 1,
1695 EXTENT_LOCKED, GFP_NOFS);
1696 goto update_block;
1697 }
1698
1699 WARN_ON(trans->alloc_exclude_nr);
1700 trans->alloc_exclude_start = ins->objectid;
1701 trans->alloc_exclude_nr = ins->offset;
1702
1703 memcpy(&keys[0], ins, sizeof(*ins));
1704 keys[1].offset = hash_extent_ref(root_objectid, ref_generation,
1705 owner, owner_offset);
1706 keys[1].objectid = ins->objectid;
1707 keys[1].type = BTRFS_EXTENT_REF_KEY;
1708 sizes[0] = sizeof(*extent_item);
1709 sizes[1] = sizeof(*ref);
1710
1711 path = btrfs_alloc_path();
1712 BUG_ON(!path);
1713
1714 ret = btrfs_insert_empty_items(trans, extent_root, path, keys,
1715 sizes, 2);
1716
1717 BUG_ON(ret);
1718 extent_item = btrfs_item_ptr(path->nodes[0], path->slots[0],
1719 struct btrfs_extent_item);
1720 btrfs_set_extent_refs(path->nodes[0], extent_item, 1);
1721 ref = btrfs_item_ptr(path->nodes[0], path->slots[0] + 1,
1722 struct btrfs_extent_ref);
1723
1724 btrfs_set_ref_root(path->nodes[0], ref, root_objectid);
1725 btrfs_set_ref_generation(path->nodes[0], ref, ref_generation);
1726 btrfs_set_ref_objectid(path->nodes[0], ref, owner);
1727 btrfs_set_ref_offset(path->nodes[0], ref, owner_offset);
1728
1729 btrfs_mark_buffer_dirty(path->nodes[0]);
1730
1731 trans->alloc_exclude_start = 0;
1732 trans->alloc_exclude_nr = 0;
1733 btrfs_free_path(path);
1734 finish_current_insert(trans, extent_root);
1735 pending_ret = del_pending_extents(trans, extent_root);
1736
1737 if (ret) {
1738 return ret;
1739 }
1740 if (pending_ret) {
1741 return pending_ret;
1742 }
1743
1744 update_block:
1745 ret = update_block_group(trans, root, ins->objectid, ins->offset, 1, 0);
1746 if (ret) {
1747 printk("update block group failed for %llu %llu\n",
1748 (unsigned long long)ins->objectid,
1749 (unsigned long long)ins->offset);
1750 BUG();
1751 }
1752 return 0;
1753 }
1754
1755 /*
1756 * helper function to allocate a block for a given tree
1757 * returns the tree buffer or NULL.
1758 */
1759 struct extent_buffer *btrfs_alloc_free_block(struct btrfs_trans_handle *trans,
1760 struct btrfs_root *root,
1761 u32 blocksize,
1762 u64 root_objectid, u64 hint,
1763 u64 empty_size)
1764 {
1765 u64 ref_generation;
1766
1767 if (root->ref_cows)
1768 ref_generation = trans->transid;
1769 else
1770 ref_generation = 0;
1771
1772
1773 return __btrfs_alloc_free_block(trans, root, blocksize, root_objectid,
1774 ref_generation, 0, 0, hint, empty_size);
1775 }
1776
1777 /*
1778 * helper function to allocate a block for a given tree
1779 * returns the tree buffer or NULL.
1780 */
1781 struct extent_buffer *__btrfs_alloc_free_block(struct btrfs_trans_handle *trans,
1782 struct btrfs_root *root,
1783 u32 blocksize,
1784 u64 root_objectid,
1785 u64 ref_generation,
1786 u64 first_objectid,
1787 int level,
1788 u64 hint,
1789 u64 empty_size)
1790 {
1791 struct btrfs_key ins;
1792 int ret;
1793 struct extent_buffer *buf;
1794
1795 ret = btrfs_alloc_extent(trans, root, blocksize,
1796 root_objectid, ref_generation,
1797 level, first_objectid, empty_size, hint,
1798 (u64)-1, &ins, 0);
1799 if (ret) {
1800 BUG_ON(ret > 0);
1801 return ERR_PTR(ret);
1802 }
1803 buf = btrfs_find_create_tree_block(root, ins.objectid, blocksize);
1804 if (!buf) {
1805 btrfs_free_extent(trans, root, ins.objectid, blocksize,
1806 root->root_key.objectid, ref_generation,
1807 0, 0, 0);
1808 BUG_ON(1);
1809 return ERR_PTR(-ENOMEM);
1810 }
1811 btrfs_set_buffer_uptodate(buf);
1812 trans->blocks_used++;
1813 return buf;
1814 }
1815
1816 static int noinline drop_leaf_ref(struct btrfs_trans_handle *trans,
1817 struct btrfs_root *root,
1818 struct extent_buffer *leaf)
1819 {
1820 u64 leaf_owner;
1821 u64 leaf_generation;
1822 struct btrfs_key key;
1823 struct btrfs_file_extent_item *fi;
1824 int i;
1825 int nritems;
1826 int ret;
1827
1828 BUG_ON(!btrfs_is_leaf(leaf));
1829 nritems = btrfs_header_nritems(leaf);
1830 leaf_owner = btrfs_header_owner(leaf);
1831 leaf_generation = btrfs_header_generation(leaf);
1832
1833 for (i = 0; i < nritems; i++) {
1834 u64 disk_bytenr;
1835
1836 btrfs_item_key_to_cpu(leaf, &key, i);
1837 if (btrfs_key_type(&key) != BTRFS_EXTENT_DATA_KEY)
1838 continue;
1839 fi = btrfs_item_ptr(leaf, i, struct btrfs_file_extent_item);
1840 if (btrfs_file_extent_type(leaf, fi) ==
1841 BTRFS_FILE_EXTENT_INLINE)
1842 continue;
1843 /*
1844 * FIXME make sure to insert a trans record that
1845 * repeats the snapshot del on crash
1846 */
1847 disk_bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
1848 if (disk_bytenr == 0)
1849 continue;
1850 ret = btrfs_free_extent(trans, root, disk_bytenr,
1851 btrfs_file_extent_disk_num_bytes(leaf, fi),
1852 leaf_owner, leaf_generation,
1853 key.objectid, key.offset, 0);
1854 BUG_ON(ret);
1855 }
1856 return 0;
1857 }
1858
1859 static void noinline reada_walk_down(struct btrfs_root *root,
1860 struct extent_buffer *node,
1861 int slot)
1862 {
1863 u64 bytenr;
1864 u64 last = 0;
1865 u32 nritems;
1866 u32 refs;
1867 u32 blocksize;
1868 int ret;
1869 int i;
1870 int level;
1871 int skipped = 0;
1872
1873 nritems = btrfs_header_nritems(node);
1874 level = btrfs_header_level(node);
1875 if (level)
1876 return;
1877
1878 for (i = slot; i < nritems && skipped < 32; i++) {
1879 bytenr = btrfs_node_blockptr(node, i);
1880 if (last && ((bytenr > last && bytenr - last > 32 * 1024) ||
1881 (last > bytenr && last - bytenr > 32 * 1024))) {
1882 skipped++;
1883 continue;
1884 }
1885 blocksize = btrfs_level_size(root, level - 1);
1886 if (i != slot) {
1887 ret = lookup_extent_ref(NULL, root, bytenr,
1888 blocksize, &refs);
1889 BUG_ON(ret);
1890 if (refs != 1) {
1891 skipped++;
1892 continue;
1893 }
1894 }
1895 mutex_unlock(&root->fs_info->fs_mutex);
1896 ret = readahead_tree_block(root, bytenr, blocksize,
1897 btrfs_node_ptr_generation(node, i));
1898 last = bytenr + blocksize;
1899 cond_resched();
1900 mutex_lock(&root->fs_info->fs_mutex);
1901 if (ret)
1902 break;
1903 }
1904 }
1905
1906 /*
1907 * helper function for drop_snapshot, this walks down the tree dropping ref
1908 * counts as it goes.
1909 */
1910 static int noinline walk_down_tree(struct btrfs_trans_handle *trans,
1911 struct btrfs_root *root,
1912 struct btrfs_path *path, int *level)
1913 {
1914 u64 root_owner;
1915 u64 root_gen;
1916 u64 bytenr;
1917 u64 ptr_gen;
1918 struct extent_buffer *next;
1919 struct extent_buffer *cur;
1920 struct extent_buffer *parent;
1921 u32 blocksize;
1922 int ret;
1923 u32 refs;
1924
1925 WARN_ON(*level < 0);
1926 WARN_ON(*level >= BTRFS_MAX_LEVEL);
1927 ret = lookup_extent_ref(trans, root,
1928 path->nodes[*level]->start,
1929 path->nodes[*level]->len, &refs);
1930 BUG_ON(ret);
1931 if (refs > 1)
1932 goto out;
1933
1934 /*
1935 * walk down to the last node level and free all the leaves
1936 */
1937 while(*level >= 0) {
1938 WARN_ON(*level < 0);
1939 WARN_ON(*level >= BTRFS_MAX_LEVEL);
1940 cur = path->nodes[*level];
1941
1942 if (btrfs_header_level(cur) != *level)
1943 WARN_ON(1);
1944
1945 if (path->slots[*level] >=
1946 btrfs_header_nritems(cur))
1947 break;
1948 if (*level == 0) {
1949 ret = drop_leaf_ref(trans, root, cur);
1950 BUG_ON(ret);
1951 break;
1952 }
1953 bytenr = btrfs_node_blockptr(cur, path->slots[*level]);
1954 ptr_gen = btrfs_node_ptr_generation(cur, path->slots[*level]);
1955 blocksize = btrfs_level_size(root, *level - 1);
1956 ret = lookup_extent_ref(trans, root, bytenr, blocksize, &refs);
1957 BUG_ON(ret);
1958 if (refs != 1) {
1959 parent = path->nodes[*level];
1960 root_owner = btrfs_header_owner(parent);
1961 root_gen = btrfs_header_generation(parent);
1962 path->slots[*level]++;
1963 ret = btrfs_free_extent(trans, root, bytenr,
1964 blocksize, root_owner,
1965 root_gen, 0, 0, 1);
1966 BUG_ON(ret);
1967 continue;
1968 }
1969 next = btrfs_find_tree_block(root, bytenr, blocksize);
1970 if (!next || !btrfs_buffer_uptodate(next, ptr_gen)) {
1971 free_extent_buffer(next);
1972 reada_walk_down(root, cur, path->slots[*level]);
1973 mutex_unlock(&root->fs_info->fs_mutex);
1974 next = read_tree_block(root, bytenr, blocksize,
1975 ptr_gen);
1976 mutex_lock(&root->fs_info->fs_mutex);
1977
1978 /* we dropped the lock, check one more time */
1979 ret = lookup_extent_ref(trans, root, bytenr,
1980 blocksize, &refs);
1981 BUG_ON(ret);
1982 if (refs != 1) {
1983 parent = path->nodes[*level];
1984 root_owner = btrfs_header_owner(parent);
1985 root_gen = btrfs_header_generation(parent);
1986
1987 path->slots[*level]++;
1988 free_extent_buffer(next);
1989 ret = btrfs_free_extent(trans, root, bytenr,
1990 blocksize,
1991 root_owner,
1992 root_gen, 0, 0, 1);
1993 BUG_ON(ret);
1994 continue;
1995 }
1996 }
1997 WARN_ON(*level <= 0);
1998 if (path->nodes[*level-1])
1999 free_extent_buffer(path->nodes[*level-1]);
2000 path->nodes[*level-1] = next;
2001 *level = btrfs_header_level(next);
2002 path->slots[*level] = 0;
2003 }
2004 out:
2005 WARN_ON(*level < 0);
2006 WARN_ON(*level >= BTRFS_MAX_LEVEL);
2007
2008 if (path->nodes[*level] == root->node) {
2009 root_owner = root->root_key.objectid;
2010 parent = path->nodes[*level];
2011 } else {
2012 parent = path->nodes[*level + 1];
2013 root_owner = btrfs_header_owner(parent);
2014 }
2015
2016 root_gen = btrfs_header_generation(parent);
2017 ret = btrfs_free_extent(trans, root, path->nodes[*level]->start,
2018 path->nodes[*level]->len,
2019 root_owner, root_gen, 0, 0, 1);
2020 free_extent_buffer(path->nodes[*level]);
2021 path->nodes[*level] = NULL;
2022 *level += 1;
2023 BUG_ON(ret);
2024 return 0;
2025 }
2026
2027 /*
2028 * helper for dropping snapshots. This walks back up the tree in the path
2029 * to find the first node higher up where we haven't yet gone through
2030 * all the slots
2031 */
2032 static int noinline walk_up_tree(struct btrfs_trans_handle *trans,
2033 struct btrfs_root *root,
2034 struct btrfs_path *path, int *level)
2035 {
2036 u64 root_owner;
2037 u64 root_gen;
2038 struct btrfs_root_item *root_item = &root->root_item;
2039 int i;
2040 int slot;
2041 int ret;
2042
2043 for(i = *level; i < BTRFS_MAX_LEVEL - 1 && path->nodes[i]; i++) {
2044 slot = path->slots[i];
2045 if (slot < btrfs_header_nritems(path->nodes[i]) - 1) {
2046 struct extent_buffer *node;
2047 struct btrfs_disk_key disk_key;
2048 node = path->nodes[i];
2049 path->slots[i]++;
2050 *level = i;
2051 WARN_ON(*level == 0);
2052 btrfs_node_key(node, &disk_key, path->slots[i]);
2053 memcpy(&root_item->drop_progress,
2054 &disk_key, sizeof(disk_key));
2055 root_item->drop_level = i;
2056 return 0;
2057 } else {
2058 if (path->nodes[*level] == root->node) {
2059 root_owner = root->root_key.objectid;
2060 root_gen =
2061 btrfs_header_generation(path->nodes[*level]);
2062 } else {
2063 struct extent_buffer *node;
2064 node = path->nodes[*level + 1];
2065 root_owner = btrfs_header_owner(node);
2066 root_gen = btrfs_header_generation(node);
2067 }
2068 ret = btrfs_free_extent(trans, root,
2069 path->nodes[*level]->start,
2070 path->nodes[*level]->len,
2071 root_owner, root_gen, 0, 0, 1);
2072 BUG_ON(ret);
2073 free_extent_buffer(path->nodes[*level]);
2074 path->nodes[*level] = NULL;
2075 *level = i + 1;
2076 }
2077 }
2078 return 1;
2079 }
2080
2081 /*
2082 * drop the reference count on the tree rooted at 'snap'. This traverses
2083 * the tree freeing any blocks that have a ref count of zero after being
2084 * decremented.
2085 */
2086 int btrfs_drop_snapshot(struct btrfs_trans_handle *trans, struct btrfs_root
2087 *root)
2088 {
2089 int ret = 0;
2090 int wret;
2091 int level;
2092 struct btrfs_path *path;
2093 int i;
2094 int orig_level;
2095 struct btrfs_root_item *root_item = &root->root_item;
2096
2097 path = btrfs_alloc_path();
2098 BUG_ON(!path);
2099
2100 level = btrfs_header_level(root->node);
2101 orig_level = level;
2102 if (btrfs_disk_key_objectid(&root_item->drop_progress) == 0) {
2103 path->nodes[level] = root->node;
2104 extent_buffer_get(root->node);
2105 path->slots[level] = 0;
2106 } else {
2107 struct btrfs_key key;
2108 struct btrfs_disk_key found_key;
2109 struct extent_buffer *node;
2110
2111 btrfs_disk_key_to_cpu(&key, &root_item->drop_progress);
2112 level = root_item->drop_level;
2113 path->lowest_level = level;
2114 wret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
2115 if (wret < 0) {
2116 ret = wret;
2117 goto out;
2118 }
2119 node = path->nodes[level];
2120 btrfs_node_key(node, &found_key, path->slots[level]);
2121 WARN_ON(memcmp(&found_key, &root_item->drop_progress,
2122 sizeof(found_key)));
2123 }
2124 while(1) {
2125 wret = walk_down_tree(trans, root, path, &level);
2126 if (wret < 0)
2127 ret = wret;
2128 if (wret != 0)
2129 break;
2130
2131 wret = walk_up_tree(trans, root, path, &level);
2132 if (wret < 0)
2133 ret = wret;
2134 if (wret != 0)
2135 break;
2136 /*
2137 ret = -EAGAIN;
2138 break;
2139 */
2140 }
2141 for (i = 0; i <= orig_level; i++) {
2142 if (path->nodes[i]) {
2143 free_extent_buffer(path->nodes[i]);
2144 path->nodes[i] = NULL;
2145 }
2146 }
2147 out:
2148 btrfs_free_path(path);
2149 return ret;
2150 }
2151
2152 int btrfs_free_block_groups(struct btrfs_fs_info *info)
2153 {
2154 u64 start;
2155 u64 end;
2156 u64 ptr;
2157 int ret;
2158 while(1) {
2159 ret = find_first_extent_bit(&info->block_group_cache, 0,
2160 &start, &end, (unsigned int)-1);
2161 if (ret)
2162 break;
2163 ret = get_state_private(&info->block_group_cache, start, &ptr);
2164 if (!ret)
2165 kfree((void *)(unsigned long)ptr);
2166 clear_extent_bits(&info->block_group_cache, start,
2167 end, (unsigned int)-1, GFP_NOFS);
2168 }
2169 while(1) {
2170 ret = find_first_extent_bit(&info->free_space_cache, 0,
2171 &start, &end, EXTENT_DIRTY);
2172 if (ret)
2173 break;
2174 clear_extent_dirty(&info->free_space_cache, start,
2175 end, GFP_NOFS);
2176 }
2177 return 0;
2178 }
2179
2180 int find_first_block_group(struct btrfs_root *root, struct btrfs_path *path,
2181 struct btrfs_key *key)
2182 {
2183 int ret;
2184 struct btrfs_key found_key;
2185 struct extent_buffer *leaf;
2186 int slot;
2187
2188 ret = btrfs_search_slot(NULL, root, key, path, 0, 0);
2189 if (ret < 0)
2190 return ret;
2191 while(1) {
2192 slot = path->slots[0];
2193 leaf = path->nodes[0];
2194 if (slot >= btrfs_header_nritems(leaf)) {
2195 ret = btrfs_next_leaf(root, path);
2196 if (ret == 0)
2197 continue;
2198 if (ret < 0)
2199 goto error;
2200 break;
2201 }
2202 btrfs_item_key_to_cpu(leaf, &found_key, slot);
2203
2204 if (found_key.objectid >= key->objectid &&
2205 found_key.type == BTRFS_BLOCK_GROUP_ITEM_KEY)
2206 return 0;
2207 path->slots[0]++;
2208 }
2209 ret = -ENOENT;
2210 error:
2211 return ret;
2212 }
2213
2214 int btrfs_read_block_groups(struct btrfs_root *root)
2215 {
2216 struct btrfs_path *path;
2217 int ret;
2218 int bit;
2219 struct btrfs_block_group_cache *cache;
2220 struct btrfs_fs_info *info = root->fs_info;
2221 struct btrfs_space_info *space_info;
2222 struct extent_io_tree *block_group_cache;
2223 struct btrfs_key key;
2224 struct btrfs_key found_key;
2225 struct extent_buffer *leaf;
2226
2227 block_group_cache = &info->block_group_cache;
2228
2229 root = info->extent_root;
2230 key.objectid = 0;
2231 key.offset = 0;
2232 btrfs_set_key_type(&key, BTRFS_BLOCK_GROUP_ITEM_KEY);
2233 path = btrfs_alloc_path();
2234 if (!path)
2235 return -ENOMEM;
2236
2237 while(1) {
2238 ret = find_first_block_group(root, path, &key);
2239 if (ret > 0) {
2240 ret = 0;
2241 goto error;
2242 }
2243 if (ret != 0) {
2244 goto error;
2245 }
2246 leaf = path->nodes[0];
2247 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
2248 cache = kmalloc(sizeof(*cache), GFP_NOFS);
2249 if (!cache) {
2250 ret = -ENOMEM;
2251 break;
2252 }
2253
2254 read_extent_buffer(leaf, &cache->item,
2255 btrfs_item_ptr_offset(leaf, path->slots[0]),
2256 sizeof(cache->item));
2257 memcpy(&cache->key, &found_key, sizeof(found_key));
2258 cache->cached = 0;
2259 cache->pinned = 0;
2260 key.objectid = found_key.objectid + found_key.offset;
2261 btrfs_release_path(root, path);
2262 cache->flags = btrfs_block_group_flags(&cache->item);
2263 bit = 0;
2264 if (cache->flags & BTRFS_BLOCK_GROUP_DATA) {
2265 bit = BLOCK_GROUP_DATA;
2266 } else if (cache->flags & BTRFS_BLOCK_GROUP_SYSTEM) {
2267 bit = BLOCK_GROUP_SYSTEM;
2268 } else if (cache->flags & BTRFS_BLOCK_GROUP_METADATA) {
2269 bit = BLOCK_GROUP_METADATA;
2270 }
2271 set_avail_alloc_bits(info, cache->flags);
2272
2273 ret = update_space_info(info, cache->flags, found_key.offset,
2274 btrfs_block_group_used(&cache->item),
2275 &space_info);
2276 BUG_ON(ret);
2277 cache->space_info = space_info;
2278
2279 /* use EXTENT_LOCKED to prevent merging */
2280 set_extent_bits(block_group_cache, found_key.objectid,
2281 found_key.objectid + found_key.offset - 1,
2282 bit | EXTENT_LOCKED, GFP_NOFS);
2283 set_state_private(block_group_cache, found_key.objectid,
2284 (unsigned long)cache);
2285
2286 if (key.objectid >=
2287 btrfs_super_total_bytes(&info->super_copy))
2288 break;
2289 }
2290 ret = 0;
2291 error:
2292 btrfs_free_path(path);
2293 return ret;
2294 }
2295
2296 int btrfs_make_block_group(struct btrfs_trans_handle *trans,
2297 struct btrfs_root *root, u64 bytes_used,
2298 u64 type, u64 chunk_objectid, u64 chunk_offset,
2299 u64 size)
2300 {
2301 int ret;
2302 int bit = 0;
2303 struct btrfs_root *extent_root;
2304 struct btrfs_block_group_cache *cache;
2305 struct extent_io_tree *block_group_cache;
2306
2307 extent_root = root->fs_info->extent_root;
2308 block_group_cache = &root->fs_info->block_group_cache;
2309
2310 cache = kzalloc(sizeof(*cache), GFP_NOFS);
2311 BUG_ON(!cache);
2312 cache->key.objectid = chunk_offset;
2313 cache->key.offset = size;
2314
2315 btrfs_set_key_type(&cache->key, BTRFS_BLOCK_GROUP_ITEM_KEY);
2316 btrfs_set_block_group_used(&cache->item, bytes_used);
2317 btrfs_set_block_group_chunk_objectid(&cache->item, chunk_objectid);
2318 cache->flags = type;
2319 btrfs_set_block_group_flags(&cache->item, type);
2320
2321 ret = update_space_info(root->fs_info, cache->flags, size, bytes_used,
2322 &cache->space_info);
2323 BUG_ON(ret);
2324
2325 bit = block_group_state_bits(type);
2326 set_extent_bits(block_group_cache, chunk_offset,
2327 chunk_offset + size - 1,
2328 bit | EXTENT_LOCKED, GFP_NOFS);
2329
2330 set_state_private(block_group_cache, chunk_offset,
2331 (unsigned long)cache);
2332 ret = btrfs_insert_item(trans, extent_root, &cache->key, &cache->item,
2333 sizeof(cache->item));
2334 BUG_ON(ret);
2335
2336 finish_current_insert(trans, extent_root);
2337 ret = del_pending_extents(trans, extent_root);
2338 BUG_ON(ret);
2339 set_avail_alloc_bits(extent_root->fs_info, type);
2340 return 0;
2341 }
2342
2343 /*
2344 * This is for converter use only.
2345 *
2346 * In that case, we don't know where are free blocks located.
2347 * Therefore all block group cache entries must be setup properly
2348 * before doing any block allocation.
2349 */
2350 int btrfs_make_block_groups(struct btrfs_trans_handle *trans,
2351 struct btrfs_root *root)
2352 {
2353 u64 total_bytes;
2354 u64 cur_start;
2355 u64 group_type;
2356 u64 group_size;
2357 u64 group_align;
2358 u64 total_data = 0;
2359 u64 total_metadata = 0;
2360 u64 chunk_objectid;
2361 int ret;
2362 int bit;
2363 struct btrfs_root *extent_root;
2364 struct btrfs_block_group_cache *cache;
2365 struct extent_io_tree *block_group_cache;
2366
2367 extent_root = root->fs_info->extent_root;
2368 block_group_cache = &root->fs_info->block_group_cache;
2369 chunk_objectid = BTRFS_FIRST_CHUNK_TREE_OBJECTID;
2370 total_bytes = btrfs_super_total_bytes(&root->fs_info->super_copy);
2371 group_align = 64 * root->sectorsize;
2372
2373 cur_start = 0;
2374 while (cur_start < total_bytes) {
2375 group_size = total_bytes / 12;
2376 group_size = min_t(u64, group_size, total_bytes - cur_start);
2377 if (cur_start == 0) {
2378 bit = BLOCK_GROUP_SYSTEM;
2379 group_type = BTRFS_BLOCK_GROUP_SYSTEM;
2380 group_size /= 4;
2381 group_size &= ~(group_align - 1);
2382 group_size = max_t(u64, group_size, 32 * 1024 * 1024);
2383 group_size = min_t(u64, group_size, 128 * 1024 * 1024);
2384 } else {
2385 group_size &= ~(group_align - 1);
2386 if (total_data >= total_metadata * 2) {
2387 group_type = BTRFS_BLOCK_GROUP_METADATA;
2388 group_size = min_t(u64, group_size,
2389 1ULL * 1024 * 1024 * 1024);
2390 total_metadata += group_size;
2391 } else {
2392 group_type = BTRFS_BLOCK_GROUP_DATA;
2393 group_size = min_t(u64, group_size,
2394 5ULL * 1024 * 1024 * 1024);
2395 total_data += group_size;
2396 }
2397 if ((total_bytes - cur_start) * 4 < group_size * 5)
2398 group_size = total_bytes - cur_start;
2399 }
2400
2401 cache = kzalloc(sizeof(*cache), GFP_NOFS);
2402 BUG_ON(!cache);
2403
2404 cache->key.objectid = cur_start;
2405 cache->key.offset = group_size;
2406 btrfs_set_key_type(&cache->key, BTRFS_BLOCK_GROUP_ITEM_KEY);
2407
2408 btrfs_set_block_group_used(&cache->item, 0);
2409 btrfs_set_block_group_chunk_objectid(&cache->item,
2410 chunk_objectid);
2411 btrfs_set_block_group_flags(&cache->item, group_type);
2412
2413 cache->flags = group_type;
2414
2415 ret = update_space_info(root->fs_info, group_type, group_size,
2416 0, &cache->space_info);
2417 BUG_ON(ret);
2418 set_avail_alloc_bits(extent_root->fs_info, group_type);
2419
2420 set_extent_bits(block_group_cache, cur_start,
2421 cur_start + group_size - 1,
2422 bit | EXTENT_LOCKED, GFP_NOFS);
2423 set_state_private(block_group_cache, cur_start,
2424 (unsigned long)cache);
2425 cur_start += group_size;
2426 }
2427 /* then insert all the items */
2428 cur_start = 0;
2429 while(cur_start < total_bytes) {
2430 cache = btrfs_lookup_block_group(root->fs_info, cur_start);
2431 BUG_ON(!cache);
2432
2433 ret = btrfs_insert_item(trans, extent_root, &cache->key, &cache->item,
2434 sizeof(cache->item));
2435 BUG_ON(ret);
2436
2437 finish_current_insert(trans, extent_root);
2438 ret = del_pending_extents(trans, extent_root);
2439 BUG_ON(ret);
2440
2441 cur_start = cache->key.objectid + cache->key.offset;
2442 }
2443 return 0;
2444 }
2445
2446 u64 btrfs_hash_extent_ref(u64 root_objectid, u64 ref_generation,
2447 u64 owner, u64 owner_offset)
2448 {
2449 return hash_extent_ref(root_objectid, ref_generation,
2450 owner, owner_offset);
2451 }
2452
2453 int btrfs_update_block_group(struct btrfs_trans_handle *trans,
2454 struct btrfs_root *root,
2455 u64 bytenr, u64 num_bytes, int alloc,
2456 int mark_free)
2457 {
2458 return update_block_group(trans, root, bytenr, num_bytes,
2459 alloc, mark_free);
2460 }
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