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Don't allow written blocks from this transaction to be reallocated
[btrfs-progs-unstable.git] / extent-tree.c
blobf3c36e10ea24df4a0af137ba545cb834db170dcf
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 int btrfs_make_block_group(struct btrfs_trans_handle *trans,
41 struct btrfs_root *root, u64 bytes_used,
42 u64 type, u64 chunk_tree, u64 chunk_objectid,
43 u64 size);
44
45 static int cache_block_group(struct btrfs_root *root,
46 struct btrfs_block_group_cache *block_group)
47 {
48 struct btrfs_path *path;
49 int ret;
50 struct btrfs_key key;
51 struct extent_buffer *leaf;
52 struct extent_io_tree *free_space_cache;
53 int slot;
54 u64 last = 0;
55 u64 hole_size;
56 u64 first_free;
57 int found = 0;
58
59 if (!block_group)
60 return 0;
61
62 root = root->fs_info->extent_root;
63 free_space_cache = &root->fs_info->free_space_cache;
64
65 if (block_group->cached)
66 return 0;
67
68 path = btrfs_alloc_path();
69 if (!path)
70 return -ENOMEM;
71
72 path->reada = 2;
73 first_free = block_group->key.objectid;
74 key.objectid = block_group->key.objectid;
75 key.offset = 0;
76 btrfs_set_key_type(&key, BTRFS_EXTENT_ITEM_KEY);
77 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
78 if (ret < 0)
79 return ret;
80 ret = btrfs_previous_item(root, path, 0, BTRFS_EXTENT_ITEM_KEY);
81 if (ret < 0)
82 return ret;
83 if (ret == 0) {
84 leaf = path->nodes[0];
85 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
86 if (key.objectid + key.offset > first_free)
87 first_free = key.objectid + key.offset;
88 }
89 while(1) {
90 leaf = path->nodes[0];
91 slot = path->slots[0];
92 if (slot >= btrfs_header_nritems(leaf)) {
93 ret = btrfs_next_leaf(root, path);
94 if (ret < 0)
95 goto err;
96 if (ret == 0) {
97 continue;
98 } else {
99 break;
100 }
101 }
102 btrfs_item_key_to_cpu(leaf, &key, slot);
103 if (key.objectid < block_group->key.objectid) {
104 goto next;
105 }
106 if (key.objectid >= block_group->key.objectid +
107 block_group->key.offset) {
108 break;
109 }
110
111 if (btrfs_key_type(&key) == BTRFS_EXTENT_ITEM_KEY) {
112 if (!found) {
113 last = first_free;
114 found = 1;
115 }
116 if (key.objectid > last) {
117 hole_size = key.objectid - last;
118 set_extent_dirty(free_space_cache, last,
119 last + hole_size - 1,
120 GFP_NOFS);
121 }
122 last = key.objectid + key.offset;
123 }
124 next:
125 path->slots[0]++;
126 }
127
128 if (!found)
129 last = first_free;
130 if (block_group->key.objectid +
131 block_group->key.offset > last) {
132 hole_size = block_group->key.objectid +
133 block_group->key.offset - last;
134 set_extent_dirty(free_space_cache, last,
135 last + hole_size - 1, GFP_NOFS);
136 }
137 block_group->cached = 1;
138 err:
139 btrfs_free_path(path);
140 return 0;
141 }
142
143 struct btrfs_block_group_cache *btrfs_lookup_block_group(struct
144 btrfs_fs_info *info,
145 u64 bytenr)
146 {
147 struct extent_io_tree *block_group_cache;
148 struct btrfs_block_group_cache *block_group = NULL;
149 u64 ptr;
150 u64 start;
151 u64 end;
152 int ret;
153
154 block_group_cache = &info->block_group_cache;
155 ret = find_first_extent_bit(block_group_cache,
156 bytenr, &start, &end,
157 BLOCK_GROUP_DATA | BLOCK_GROUP_METADATA |
158 BLOCK_GROUP_SYSTEM);
159 if (ret) {
160 return NULL;
161 }
162 ret = get_state_private(block_group_cache, start, &ptr);
163 if (ret)
164 return NULL;
165
166 block_group = (struct btrfs_block_group_cache *)(unsigned long)ptr;
167 if (block_group->key.objectid <= bytenr && bytenr <
168 block_group->key.objectid + block_group->key.offset)
169 return block_group;
170 return NULL;
171 }
172
173 static int block_group_bits(struct btrfs_block_group_cache *cache, u64 bits)
174 {
175 return (cache->flags & bits) == bits;
176 }
177
178 static int noinline find_search_start(struct btrfs_root *root,
179 struct btrfs_block_group_cache **cache_ret,
180 u64 *start_ret, int num, int data)
181 {
182 int ret;
183 struct btrfs_block_group_cache *cache = *cache_ret;
184 u64 last;
185 u64 start = 0;
186 u64 end = 0;
187 u64 cache_miss = 0;
188 u64 search_start = *start_ret;
189 int wrapped = 0;
190
191 if (!cache) {
192 goto out;
193 }
194 again:
195 ret = cache_block_group(root, cache);
196 if (ret)
197 goto out;
198
199 last = max(search_start, cache->key.objectid);
200 if (!block_group_bits(cache, data)) {
201 goto new_group;
202 }
203
204 while(1) {
205 ret = find_first_extent_bit(&root->fs_info->free_space_cache,
206 last, &start, &end, EXTENT_DIRTY);
207 if (ret) {
208 if (!cache_miss)
209 cache_miss = last;
210 goto new_group;
211 }
212
213 start = max(last, start);
214 last = end + 1;
215 if (last - start < num) {
216 if (last == cache->key.objectid + cache->key.offset)
217 cache_miss = start;
218 continue;
219 }
220 if (start + num > cache->key.objectid + cache->key.offset)
221 goto new_group;
222 *start_ret = start;
223 return 0;
224 }
225 out:
226 cache = btrfs_lookup_block_group(root->fs_info, search_start);
227 if (!cache) {
228 printk("Unable to find block group for %llu\n",
229 (unsigned long long)search_start);
230 WARN_ON(1);
231 }
232 return -ENOSPC;
233
234 new_group:
235 last = cache->key.objectid + cache->key.offset;
236 wrapped:
237 cache = btrfs_lookup_block_group(root->fs_info, last);
238 if (!cache) {
239 no_cache:
240 if (!wrapped) {
241 wrapped = 1;
242 last = search_start;
243 goto wrapped;
244 }
245 goto out;
246 }
247 if (cache_miss && !cache->cached) {
248 cache_block_group(root, cache);
249 last = cache_miss;
250 cache = btrfs_lookup_block_group(root->fs_info, last);
251 }
252 cache = btrfs_find_block_group(root, cache, last, data, 0);
253 if (!cache)
254 goto no_cache;
255 *cache_ret = cache;
256 cache_miss = 0;
257 goto again;
258 }
259
260 static u64 div_factor(u64 num, int factor)
261 {
262 if (factor == 10)
263 return num;
264 num *= factor;
265 num /= 10;
266 return num;
267 }
268
269 static int block_group_state_bits(u64 flags)
270 {
271 int bits = 0;
272 if (flags & BTRFS_BLOCK_GROUP_DATA)
273 bits |= BLOCK_GROUP_DATA;
274 if (flags & BTRFS_BLOCK_GROUP_METADATA)
275 bits |= BLOCK_GROUP_METADATA;
276 if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
277 bits |= BLOCK_GROUP_SYSTEM;
278 return bits;
279 }
280
281 struct btrfs_block_group_cache *btrfs_find_block_group(struct btrfs_root *root,
282 struct btrfs_block_group_cache
283 *hint, u64 search_start,
284 int data, int owner)
285 {
286 struct btrfs_block_group_cache *cache;
287 struct extent_io_tree *block_group_cache;
288 struct btrfs_block_group_cache *found_group = NULL;
289 struct btrfs_fs_info *info = root->fs_info;
290 u64 used;
291 u64 last = 0;
292 u64 hint_last;
293 u64 start;
294 u64 end;
295 u64 free_check;
296 u64 ptr;
297 int bit;
298 int ret;
299 int full_search = 0;
300 int factor = 8;
301
302 block_group_cache = &info->block_group_cache;
303
304 if (!owner)
305 factor = 8;
306
307 bit = block_group_state_bits(data);
308
309 if (search_start) {
310 struct btrfs_block_group_cache *shint;
311 shint = btrfs_lookup_block_group(info, search_start);
312 if (shint && block_group_bits(shint, data)) {
313 used = btrfs_block_group_used(&shint->item);
314 if (used + shint->pinned <
315 div_factor(shint->key.offset, factor)) {
316 return shint;
317 }
318 }
319 }
320 if (hint && block_group_bits(hint, data)) {
321 used = btrfs_block_group_used(&hint->item);
322 if (used + hint->pinned <
323 div_factor(hint->key.offset, factor)) {
324 return hint;
325 }
326 last = hint->key.objectid + hint->key.offset;
327 hint_last = last;
328 } else {
329 if (hint)
330 hint_last = max(hint->key.objectid, search_start);
331 else
332 hint_last = search_start;
333
334 last = hint_last;
335 }
336 again:
337 while(1) {
338 ret = find_first_extent_bit(block_group_cache, last,
339 &start, &end, bit);
340 if (ret)
341 break;
342
343 ret = get_state_private(block_group_cache, start, &ptr);
344 if (ret)
345 break;
346
347 cache = (struct btrfs_block_group_cache *)(unsigned long)ptr;
348 last = cache->key.objectid + cache->key.offset;
349 used = btrfs_block_group_used(&cache->item);
350
351 if (block_group_bits(cache, data)) {
352 if (full_search)
353 free_check = cache->key.offset;
354 else
355 free_check = div_factor(cache->key.offset,
356 factor);
357
358 if (used + cache->pinned < free_check) {
359 found_group = cache;
360 goto found;
361 }
362 }
363 cond_resched();
364 }
365 if (!full_search) {
366 last = search_start;
367 full_search = 1;
368 goto again;
369 }
370 found:
371 return found_group;
372 }
373
374 static u64 hash_extent_ref(u64 root_objectid, u64 ref_generation,
375 u64 owner, u64 owner_offset)
376 {
377 u32 high_crc = ~(u32)0;
378 u32 low_crc = ~(u32)0;
379 __le64 lenum;
380
381 lenum = cpu_to_le64(root_objectid);
382 high_crc = crc32c(high_crc, &lenum, sizeof(lenum));
383 lenum = cpu_to_le64(ref_generation);
384 low_crc = crc32c(low_crc, &lenum, sizeof(lenum));
385 if (owner >= BTRFS_FIRST_FREE_OBJECTID) {
386 lenum = cpu_to_le64(owner);
387 low_crc = crc32c(low_crc, &lenum, sizeof(lenum));
388 lenum = cpu_to_le64(owner_offset);
389 low_crc = crc32c(low_crc, &lenum, sizeof(lenum));
390 }
391 return ((u64)high_crc << 32) | (u64)low_crc;
392 }
393
394 static int match_extent_ref(struct extent_buffer *leaf,
395 struct btrfs_extent_ref *disk_ref,
396 struct btrfs_extent_ref *cpu_ref)
397 {
398 int ret;
399 int len;
400
401 if (cpu_ref->objectid)
402 len = sizeof(*cpu_ref);
403 else
404 len = 2 * sizeof(u64);
405 ret = memcmp_extent_buffer(leaf, cpu_ref, (unsigned long)disk_ref,
406 len);
407 return ret == 0;
408 }
409
410 static int noinline lookup_extent_backref(struct btrfs_trans_handle *trans,
411 struct btrfs_root *root,
412 struct btrfs_path *path, u64 bytenr,
413 u64 root_objectid,
414 u64 ref_generation, u64 owner,
415 u64 owner_offset, int del)
416 {
417 u64 hash;
418 struct btrfs_key key;
419 struct btrfs_key found_key;
420 struct btrfs_extent_ref ref;
421 struct extent_buffer *leaf;
422 struct btrfs_extent_ref *disk_ref;
423 int ret;
424 int ret2;
425
426 btrfs_set_stack_ref_root(&ref, root_objectid);
427 btrfs_set_stack_ref_generation(&ref, ref_generation);
428 btrfs_set_stack_ref_objectid(&ref, owner);
429 btrfs_set_stack_ref_offset(&ref, owner_offset);
430
431 hash = hash_extent_ref(root_objectid, ref_generation, owner,
432 owner_offset);
433 key.offset = hash;
434 key.objectid = bytenr;
435 key.type = BTRFS_EXTENT_REF_KEY;
436
437 while (1) {
438 ret = btrfs_search_slot(trans, root, &key, path,
439 del ? -1 : 0, del);
440 if (ret < 0)
441 goto out;
442 leaf = path->nodes[0];
443 if (ret != 0) {
444 u32 nritems = btrfs_header_nritems(leaf);
445 if (path->slots[0] >= nritems) {
446 ret2 = btrfs_next_leaf(root, path);
447 if (ret2)
448 goto out;
449 leaf = path->nodes[0];
450 }
451 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
452 if (found_key.objectid != bytenr ||
453 found_key.type != BTRFS_EXTENT_REF_KEY)
454 goto out;
455 key.offset = found_key.offset;
456 if (del) {
457 btrfs_release_path(root, path);
458 continue;
459 }
460 }
461 disk_ref = btrfs_item_ptr(path->nodes[0],
462 path->slots[0],
463 struct btrfs_extent_ref);
464 if (match_extent_ref(path->nodes[0], disk_ref, &ref)) {
465 ret = 0;
466 goto out;
467 }
468 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
469 key.offset = found_key.offset + 1;
470 btrfs_release_path(root, path);
471 }
472 out:
473 return ret;
474 }
475
476 /*
477 * Back reference rules. Back refs have three main goals:
478 *
479 * 1) differentiate between all holders of references to an extent so that
480 * when a reference is dropped we can make sure it was a valid reference
481 * before freeing the extent.
482 *
483 * 2) Provide enough information to quickly find the holders of an extent
484 * if we notice a given block is corrupted or bad.
485 *
486 * 3) Make it easy to migrate blocks for FS shrinking or storage pool
487 * maintenance. This is actually the same as #2, but with a slightly
488 * different use case.
489 *
490 * File extents can be referenced by:
491 *
492 * - multiple snapshots, subvolumes, or different generations in one subvol
493 * - different files inside a single subvolume (in theory, not implemented yet)
494 * - different offsets inside a file (bookend extents in file.c)
495 *
496 * The extent ref structure has fields for:
497 *
498 * - Objectid of the subvolume root
499 * - Generation number of the tree holding the reference
500 * - objectid of the file holding the reference
501 * - offset in the file corresponding to the key holding the reference
502 *
503 * When a file extent is allocated the fields are filled in:
504 * (root_key.objectid, trans->transid, inode objectid, offset in file)
505 *
506 * When a leaf is cow'd new references are added for every file extent found
507 * in the leaf. It looks the same as the create case, but trans->transid
508 * will be different when the block is cow'd.
509 *
510 * (root_key.objectid, trans->transid, inode objectid, offset in file)
511 *
512 * When a file extent is removed either during snapshot deletion or file
513 * truncation, the corresponding back reference is found
514 * by searching for:
515 *
516 * (btrfs_header_owner(leaf), btrfs_header_generation(leaf),
517 * inode objectid, offset in file)
518 *
519 * Btree extents can be referenced by:
520 *
521 * - Different subvolumes
522 * - Different generations of the same subvolume
523 *
524 * Storing sufficient information for a full reverse mapping of a btree
525 * block would require storing the lowest key of the block in the backref,
526 * and it would require updating that lowest key either before write out or
527 * every time it changed. Instead, the objectid of the lowest key is stored
528 * along with the level of the tree block. This provides a hint
529 * about where in the btree the block can be found. Searches through the
530 * btree only need to look for a pointer to that block, so they stop one
531 * level higher than the level recorded in the backref.
532 *
533 * Some btrees do not do reference counting on their extents. These
534 * include the extent tree and the tree of tree roots. Backrefs for these
535 * trees always have a generation of zero.
536 *
537 * When a tree block is created, back references are inserted:
538 *
539 * (root->root_key.objectid, trans->transid or zero, level, lowest_key_objectid)
540 *
541 * When a tree block is cow'd in a reference counted root,
542 * new back references are added for all the blocks it points to.
543 * These are of the form (trans->transid will have increased since creation):
544 *
545 * (root->root_key.objectid, trans->transid, level, lowest_key_objectid)
546 *
547 * Because the lowest_key_objectid and the level are just hints
548 * they are not used when backrefs are deleted. When a backref is deleted:
549 *
550 * if backref was for a tree root:
551 * root_objectid = root->root_key.objectid
552 * else
553 * root_objectid = btrfs_header_owner(parent)
554 *
555 * (root_objectid, btrfs_header_generation(parent) or zero, 0, 0)
556 *
557 * Back Reference Key hashing:
558 *
559 * Back references have four fields, each 64 bits long. Unfortunately,
560 * This is hashed into a single 64 bit number and placed into the key offset.
561 * The key objectid corresponds to the first byte in the extent, and the
562 * key type is set to BTRFS_EXTENT_REF_KEY
563 */
564 int btrfs_insert_extent_backref(struct btrfs_trans_handle *trans,
565 struct btrfs_root *root,
566 struct btrfs_path *path, u64 bytenr,
567 u64 root_objectid, u64 ref_generation,
568 u64 owner, u64 owner_offset)
569 {
570 u64 hash;
571 struct btrfs_key key;
572 struct btrfs_extent_ref ref;
573 struct btrfs_extent_ref *disk_ref;
574 int ret;
575
576 btrfs_set_stack_ref_root(&ref, root_objectid);
577 btrfs_set_stack_ref_generation(&ref, ref_generation);
578 btrfs_set_stack_ref_objectid(&ref, owner);
579 btrfs_set_stack_ref_offset(&ref, owner_offset);
580
581 hash = hash_extent_ref(root_objectid, ref_generation, owner,
582 owner_offset);
583 key.offset = hash;
584 key.objectid = bytenr;
585 key.type = BTRFS_EXTENT_REF_KEY;
586
587 ret = btrfs_insert_empty_item(trans, root, path, &key, sizeof(ref));
588 while (ret == -EEXIST) {
589 disk_ref = btrfs_item_ptr(path->nodes[0], path->slots[0],
590 struct btrfs_extent_ref);
591 if (match_extent_ref(path->nodes[0], disk_ref, &ref))
592 goto out;
593 key.offset++;
594 btrfs_release_path(root, path);
595 ret = btrfs_insert_empty_item(trans, root, path, &key,
596 sizeof(ref));
597 }
598 if (ret)
599 goto out;
600 disk_ref = btrfs_item_ptr(path->nodes[0], path->slots[0],
601 struct btrfs_extent_ref);
602 write_extent_buffer(path->nodes[0], &ref, (unsigned long)disk_ref,
603 sizeof(ref));
604 btrfs_mark_buffer_dirty(path->nodes[0]);
605 out:
606 btrfs_release_path(root, path);
607 return ret;
608 }
609
610 int btrfs_inc_extent_ref(struct btrfs_trans_handle *trans,
611 struct btrfs_root *root,
612 u64 bytenr, u64 num_bytes,
613 u64 root_objectid, u64 ref_generation,
614 u64 owner, u64 owner_offset)
615 {
616 struct btrfs_path *path;
617 int ret;
618 struct btrfs_key key;
619 struct extent_buffer *l;
620 struct btrfs_extent_item *item;
621 u32 refs;
622
623 WARN_ON(num_bytes < root->sectorsize);
624 path = btrfs_alloc_path();
625 if (!path)
626 return -ENOMEM;
627
628 key.objectid = bytenr;
629 btrfs_set_key_type(&key, BTRFS_EXTENT_ITEM_KEY);
630 key.offset = num_bytes;
631 ret = btrfs_search_slot(trans, root->fs_info->extent_root, &key, path,
632 0, 1);
633 if (ret < 0)
634 return ret;
635 if (ret != 0) {
636 BUG();
637 }
638 BUG_ON(ret != 0);
639 l = path->nodes[0];
640 item = btrfs_item_ptr(l, path->slots[0], struct btrfs_extent_item);
641 refs = btrfs_extent_refs(l, item);
642 btrfs_set_extent_refs(l, item, refs + 1);
643 btrfs_mark_buffer_dirty(path->nodes[0]);
644
645 btrfs_release_path(root->fs_info->extent_root, path);
646
647 ret = btrfs_insert_extent_backref(trans, root->fs_info->extent_root,
648 path, bytenr, root_objectid,
649 ref_generation, owner, owner_offset);
650 BUG_ON(ret);
651 finish_current_insert(trans, root->fs_info->extent_root);
652 del_pending_extents(trans, root->fs_info->extent_root);
653
654 btrfs_free_path(path);
655 return 0;
656 }
657
658 int btrfs_extent_post_op(struct btrfs_trans_handle *trans,
659 struct btrfs_root *root)
660 {
661 finish_current_insert(trans, root->fs_info->extent_root);
662 del_pending_extents(trans, root->fs_info->extent_root);
663 return 0;
664 }
665
666 static int lookup_extent_ref(struct btrfs_trans_handle *trans,
667 struct btrfs_root *root, u64 bytenr,
668 u64 num_bytes, u32 *refs)
669 {
670 struct btrfs_path *path;
671 int ret;
672 struct btrfs_key key;
673 struct extent_buffer *l;
674 struct btrfs_extent_item *item;
675
676 WARN_ON(num_bytes < root->sectorsize);
677 path = btrfs_alloc_path();
678 key.objectid = bytenr;
679 key.offset = num_bytes;
680 btrfs_set_key_type(&key, BTRFS_EXTENT_ITEM_KEY);
681 ret = btrfs_search_slot(trans, root->fs_info->extent_root, &key, path,
682 0, 0);
683 if (ret < 0)
684 goto out;
685 if (ret != 0) {
686 btrfs_print_leaf(root, path->nodes[0]);
687 printk("failed to find block number %llu\n",
688 (unsigned long long)bytenr);
689 BUG();
690 }
691 l = path->nodes[0];
692 item = btrfs_item_ptr(l, path->slots[0], struct btrfs_extent_item);
693 *refs = btrfs_extent_refs(l, item);
694 out:
695 btrfs_free_path(path);
696 return 0;
697 }
698
699 u32 btrfs_count_snapshots_in_path(struct btrfs_root *root,
700 struct btrfs_path *count_path,
701 u64 first_extent)
702 {
703 struct btrfs_root *extent_root = root->fs_info->extent_root;
704 struct btrfs_path *path;
705 u64 bytenr;
706 u64 found_objectid;
707 u64 root_objectid = root->root_key.objectid;
708 u32 total_count = 0;
709 u32 cur_count;
710 u32 refs;
711 u32 nritems;
712 int ret;
713 struct btrfs_key key;
714 struct btrfs_key found_key;
715 struct extent_buffer *l;
716 struct btrfs_extent_item *item;
717 struct btrfs_extent_ref *ref_item;
718 int level = -1;
719
720 path = btrfs_alloc_path();
721 again:
722 if (level == -1)
723 bytenr = first_extent;
724 else
725 bytenr = count_path->nodes[level]->start;
726
727 cur_count = 0;
728 key.objectid = bytenr;
729 key.offset = 0;
730
731 btrfs_set_key_type(&key, BTRFS_EXTENT_ITEM_KEY);
732 ret = btrfs_search_slot(NULL, extent_root, &key, path, 0, 0);
733 if (ret < 0)
734 goto out;
735 BUG_ON(ret == 0);
736
737 l = path->nodes[0];
738 btrfs_item_key_to_cpu(l, &found_key, path->slots[0]);
739
740 if (found_key.objectid != bytenr ||
741 found_key.type != BTRFS_EXTENT_ITEM_KEY) {
742 goto out;
743 }
744
745 item = btrfs_item_ptr(l, path->slots[0], struct btrfs_extent_item);
746 refs = btrfs_extent_refs(l, item);
747 while (1) {
748 nritems = btrfs_header_nritems(l);
749 if (path->slots[0] >= nritems) {
750 ret = btrfs_next_leaf(extent_root, path);
751 if (ret == 0)
752 continue;
753 break;
754 }
755 btrfs_item_key_to_cpu(l, &found_key, path->slots[0]);
756 if (found_key.objectid != bytenr)
757 break;
758 if (found_key.type != BTRFS_EXTENT_REF_KEY) {
759 path->slots[0]++;
760 continue;
761 }
762
763 cur_count++;
764 ref_item = btrfs_item_ptr(l, path->slots[0],
765 struct btrfs_extent_ref);
766 found_objectid = btrfs_ref_root(l, ref_item);
767
768 if (found_objectid != root_objectid) {
769 total_count = 2;
770 goto out;
771 }
772 total_count = 1;
773 path->slots[0]++;
774 }
775 if (cur_count == 0) {
776 total_count = 0;
777 goto out;
778 }
779 if (level >= 0 && root->node == count_path->nodes[level])
780 goto out;
781 level++;
782 btrfs_release_path(root, path);
783 goto again;
784
785 out:
786 btrfs_free_path(path);
787 return total_count;
788 }
789 int btrfs_inc_root_ref(struct btrfs_trans_handle *trans,
790 struct btrfs_root *root, u64 owner_objectid)
791 {
792 u64 generation;
793 u64 key_objectid;
794 u64 level;
795 u32 nritems;
796 struct btrfs_disk_key disk_key;
797
798 level = btrfs_header_level(root->node);
799 generation = trans->transid;
800 nritems = btrfs_header_nritems(root->node);
801 if (nritems > 0) {
802 if (level == 0)
803 btrfs_item_key(root->node, &disk_key, 0);
804 else
805 btrfs_node_key(root->node, &disk_key, 0);
806 key_objectid = btrfs_disk_key_objectid(&disk_key);
807 } else {
808 key_objectid = 0;
809 }
810 return btrfs_inc_extent_ref(trans, root, root->node->start,
811 root->node->len, owner_objectid,
812 generation, level, key_objectid);
813 }
814
815 int btrfs_inc_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root,
816 struct extent_buffer *buf)
817 {
818 u64 bytenr;
819 u32 nritems;
820 struct btrfs_key key;
821 struct btrfs_file_extent_item *fi;
822 int i;
823 int level;
824 int ret;
825 int faili;
826
827 if (!root->ref_cows)
828 return 0;
829
830 level = btrfs_header_level(buf);
831 nritems = btrfs_header_nritems(buf);
832 for (i = 0; i < nritems; i++) {
833 if (level == 0) {
834 u64 disk_bytenr;
835 btrfs_item_key_to_cpu(buf, &key, i);
836 if (btrfs_key_type(&key) != BTRFS_EXTENT_DATA_KEY)
837 continue;
838 fi = btrfs_item_ptr(buf, i,
839 struct btrfs_file_extent_item);
840 if (btrfs_file_extent_type(buf, fi) ==
841 BTRFS_FILE_EXTENT_INLINE)
842 continue;
843 disk_bytenr = btrfs_file_extent_disk_bytenr(buf, fi);
844 if (disk_bytenr == 0)
845 continue;
846 ret = btrfs_inc_extent_ref(trans, root, disk_bytenr,
847 btrfs_file_extent_disk_num_bytes(buf, fi),
848 root->root_key.objectid, trans->transid,
849 key.objectid, key.offset);
850 if (ret) {
851 faili = i;
852 goto fail;
853 }
854 } else {
855 bytenr = btrfs_node_blockptr(buf, i);
856 btrfs_node_key_to_cpu(buf, &key, i);
857 ret = btrfs_inc_extent_ref(trans, root, bytenr,
858 btrfs_level_size(root, level - 1),
859 root->root_key.objectid,
860 trans->transid,
861 level - 1, key.objectid);
862 if (ret) {
863 faili = i;
864 goto fail;
865 }
866 }
867 }
868 return 0;
869 fail:
870 WARN_ON(1);
871 #if 0
872 for (i =0; i < faili; i++) {
873 if (level == 0) {
874 u64 disk_bytenr;
875 btrfs_item_key_to_cpu(buf, &key, i);
876 if (btrfs_key_type(&key) != BTRFS_EXTENT_DATA_KEY)
877 continue;
878 fi = btrfs_item_ptr(buf, i,
879 struct btrfs_file_extent_item);
880 if (btrfs_file_extent_type(buf, fi) ==
881 BTRFS_FILE_EXTENT_INLINE)
882 continue;
883 disk_bytenr = btrfs_file_extent_disk_bytenr(buf, fi);
884 if (disk_bytenr == 0)
885 continue;
886 err = btrfs_free_extent(trans, root, disk_bytenr,
887 btrfs_file_extent_disk_num_bytes(buf,
888 fi), 0);
889 BUG_ON(err);
890 } else {
891 bytenr = btrfs_node_blockptr(buf, i);
892 err = btrfs_free_extent(trans, root, bytenr,
893 btrfs_level_size(root, level - 1), 0);
894 BUG_ON(err);
895 }
896 }
897 #endif
898 return ret;
899 }
900
901 static int write_one_cache_group(struct btrfs_trans_handle *trans,
902 struct btrfs_root *root,
903 struct btrfs_path *path,
904 struct btrfs_block_group_cache *cache)
905 {
906 int ret;
907 int pending_ret;
908 struct btrfs_root *extent_root = root->fs_info->extent_root;
909 unsigned long bi;
910 struct extent_buffer *leaf;
911
912 ret = btrfs_search_slot(trans, extent_root, &cache->key, path, 0, 1);
913 if (ret < 0)
914 goto fail;
915 BUG_ON(ret);
916
917 leaf = path->nodes[0];
918 bi = btrfs_item_ptr_offset(leaf, path->slots[0]);
919 write_extent_buffer(leaf, &cache->item, bi, sizeof(cache->item));
920 btrfs_mark_buffer_dirty(leaf);
921 btrfs_release_path(extent_root, path);
922 fail:
923 finish_current_insert(trans, extent_root);
924 pending_ret = del_pending_extents(trans, extent_root);
925 if (ret)
926 return ret;
927 if (pending_ret)
928 return pending_ret;
929 return 0;
930
931 }
932
933 int btrfs_write_dirty_block_groups(struct btrfs_trans_handle *trans,
934 struct btrfs_root *root)
935 {
936 struct extent_io_tree *block_group_cache;
937 struct btrfs_block_group_cache *cache;
938 int ret;
939 int err = 0;
940 int werr = 0;
941 struct btrfs_path *path;
942 u64 last = 0;
943 u64 start;
944 u64 end;
945 u64 ptr;
946
947 block_group_cache = &root->fs_info->block_group_cache;
948 path = btrfs_alloc_path();
949 if (!path)
950 return -ENOMEM;
951
952 while(1) {
953 ret = find_first_extent_bit(block_group_cache, last,
954 &start, &end, BLOCK_GROUP_DIRTY);
955 if (ret)
956 break;
957
958 last = end + 1;
959 ret = get_state_private(block_group_cache, start, &ptr);
960 if (ret)
961 break;
962
963 cache = (struct btrfs_block_group_cache *)(unsigned long)ptr;
964 err = write_one_cache_group(trans, root,
965 path, cache);
966 /*
967 * if we fail to write the cache group, we want
968 * to keep it marked dirty in hopes that a later
969 * write will work
970 */
971 if (err) {
972 werr = err;
973 continue;
974 }
975 clear_extent_bits(block_group_cache, start, end,
976 BLOCK_GROUP_DIRTY, GFP_NOFS);
977 }
978 btrfs_free_path(path);
979 return werr;
980 }
981
982 static struct btrfs_space_info *__find_space_info(struct btrfs_fs_info *info,
983 u64 flags)
984 {
985 struct list_head *head = &info->space_info;
986 struct list_head *cur;
987 struct btrfs_space_info *found;
988 list_for_each(cur, head) {
989 found = list_entry(cur, struct btrfs_space_info, list);
990 if (found->flags == flags)
991 return found;
992 }
993 return NULL;
994
995 }
996
997 static int update_space_info(struct btrfs_fs_info *info, u64 flags,
998 u64 total_bytes, u64 bytes_used,
999 struct btrfs_space_info **space_info)
1000 {
1001 struct btrfs_space_info *found;
1002
1003 found = __find_space_info(info, flags);
1004 if (found) {
1005 found->total_bytes += total_bytes;
1006 found->bytes_used += bytes_used;
1007 WARN_ON(found->total_bytes < found->bytes_used);
1008 *space_info = found;
1009 return 0;
1010 }
1011 found = kmalloc(sizeof(*found), GFP_NOFS);
1012 if (!found)
1013 return -ENOMEM;
1014
1015 list_add(&found->list, &info->space_info);
1016 found->flags = flags;
1017 found->total_bytes = total_bytes;
1018 found->bytes_used = bytes_used;
1019 found->bytes_pinned = 0;
1020 found->full = 0;
1021 *space_info = found;
1022 return 0;
1023 }
1024
1025
1026 static void set_avail_alloc_bits(struct btrfs_fs_info *fs_info, u64 flags)
1027 {
1028 u64 extra_flags = flags & (BTRFS_BLOCK_GROUP_RAID0 |
1029 BTRFS_BLOCK_GROUP_RAID1 |
1030 BTRFS_BLOCK_GROUP_DUP);
1031 if (extra_flags) {
1032 if (flags & BTRFS_BLOCK_GROUP_DATA)
1033 fs_info->avail_data_alloc_bits |= extra_flags;
1034 if (flags & BTRFS_BLOCK_GROUP_METADATA)
1035 fs_info->avail_metadata_alloc_bits |= extra_flags;
1036 if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
1037 fs_info->avail_system_alloc_bits |= extra_flags;
1038 }
1039 }
1040
1041 static int do_chunk_alloc(struct btrfs_trans_handle *trans,
1042 struct btrfs_root *extent_root, u64 alloc_bytes,
1043 u64 flags)
1044 {
1045 struct btrfs_space_info *space_info;
1046 u64 thresh;
1047 u64 start;
1048 u64 num_bytes;
1049 int ret;
1050
1051 space_info = __find_space_info(extent_root->fs_info, flags);
1052 if (!space_info) {
1053 ret = update_space_info(extent_root->fs_info, flags,
1054 0, 0, &space_info);
1055 BUG_ON(ret);
1056 }
1057 BUG_ON(!space_info);
1058
1059 if (space_info->full)
1060 return 0;
1061
1062 thresh = div_factor(space_info->total_bytes, 7);
1063 if ((space_info->bytes_used + space_info->bytes_pinned + alloc_bytes) <
1064 thresh)
1065 return 0;
1066
1067 ret = btrfs_alloc_chunk(trans, extent_root, &start, &num_bytes, flags);
1068 if (ret == -ENOSPC) {
1069 printk("space info full %llu\n", (unsigned long long)flags);
1070 space_info->full = 1;
1071 return 0;
1072 }
1073
1074 BUG_ON(ret);
1075
1076 ret = btrfs_make_block_group(trans, extent_root, 0, flags,
1077 extent_root->fs_info->chunk_root->root_key.objectid,
1078 start, num_bytes);
1079 BUG_ON(ret);
1080 return 0;
1081 }
1082
1083 static int update_block_group(struct btrfs_trans_handle *trans,
1084 struct btrfs_root *root,
1085 u64 bytenr, u64 num_bytes, int alloc,
1086 int mark_free)
1087 {
1088 struct btrfs_block_group_cache *cache;
1089 struct btrfs_fs_info *info = root->fs_info;
1090 u64 total = num_bytes;
1091 u64 old_val;
1092 u64 byte_in_group;
1093 u64 start;
1094 u64 end;
1095
1096 while(total) {
1097 cache = btrfs_lookup_block_group(info, bytenr);
1098 if (!cache) {
1099 return -1;
1100 }
1101 byte_in_group = bytenr - cache->key.objectid;
1102 WARN_ON(byte_in_group > cache->key.offset);
1103 start = cache->key.objectid;
1104 end = start + cache->key.offset - 1;
1105 set_extent_bits(&info->block_group_cache, start, end,
1106 BLOCK_GROUP_DIRTY, GFP_NOFS);
1107
1108 old_val = btrfs_block_group_used(&cache->item);
1109 num_bytes = min(total, cache->key.offset - byte_in_group);
1110 if (alloc) {
1111 old_val += num_bytes;
1112 cache->space_info->bytes_used += num_bytes;
1113 } else {
1114 old_val -= num_bytes;
1115 cache->space_info->bytes_used -= num_bytes;
1116 if (mark_free) {
1117 set_extent_dirty(&info->free_space_cache,
1118 bytenr, bytenr + num_bytes - 1,
1119 GFP_NOFS);
1120 }
1121 }
1122 btrfs_set_block_group_used(&cache->item, old_val);
1123 total -= num_bytes;
1124 bytenr += num_bytes;
1125 }
1126 return 0;
1127 }
1128
1129 static int update_pinned_extents(struct btrfs_root *root,
1130 u64 bytenr, u64 num, int pin)
1131 {
1132 u64 len;
1133 struct btrfs_block_group_cache *cache;
1134 struct btrfs_fs_info *fs_info = root->fs_info;
1135
1136 if (pin) {
1137 set_extent_dirty(&fs_info->pinned_extents,
1138 bytenr, bytenr + num - 1, GFP_NOFS);
1139 } else {
1140 clear_extent_dirty(&fs_info->pinned_extents,
1141 bytenr, bytenr + num - 1, GFP_NOFS);
1142 }
1143 while (num > 0) {
1144 cache = btrfs_lookup_block_group(fs_info, bytenr);
1145 WARN_ON(!cache);
1146 len = min(num, cache->key.offset -
1147 (bytenr - cache->key.objectid));
1148 if (pin) {
1149 cache->pinned += len;
1150 cache->space_info->bytes_pinned += len;
1151 fs_info->total_pinned += len;
1152 } else {
1153 cache->pinned -= len;
1154 cache->space_info->bytes_pinned -= len;
1155 fs_info->total_pinned -= len;
1156 }
1157 bytenr += len;
1158 num -= len;
1159 }
1160 return 0;
1161 }
1162
1163 int btrfs_copy_pinned(struct btrfs_root *root, struct extent_io_tree *copy)
1164 {
1165 u64 last = 0;
1166 u64 start;
1167 u64 end;
1168 struct extent_io_tree *pinned_extents = &root->fs_info->pinned_extents;
1169 int ret;
1170
1171 while(1) {
1172 ret = find_first_extent_bit(pinned_extents, last,
1173 &start, &end, EXTENT_DIRTY);
1174 if (ret)
1175 break;
1176 set_extent_dirty(copy, start, end, GFP_NOFS);
1177 last = end + 1;
1178 }
1179 return 0;
1180 }
1181
1182 int btrfs_finish_extent_commit(struct btrfs_trans_handle *trans,
1183 struct btrfs_root *root,
1184 struct extent_io_tree *unpin)
1185 {
1186 u64 start;
1187 u64 end;
1188 int ret;
1189 struct extent_io_tree *free_space_cache;
1190 free_space_cache = &root->fs_info->free_space_cache;
1191
1192 while(1) {
1193 ret = find_first_extent_bit(unpin, 0, &start, &end,
1194 EXTENT_DIRTY);
1195 if (ret)
1196 break;
1197 update_pinned_extents(root, start, end + 1 - start, 0);
1198 clear_extent_dirty(unpin, start, end, GFP_NOFS);
1199 set_extent_dirty(free_space_cache, start, end, GFP_NOFS);
1200 }
1201 return 0;
1202 }
1203
1204 static int finish_current_insert(struct btrfs_trans_handle *trans,
1205 struct btrfs_root *extent_root)
1206 {
1207 u64 start;
1208 u64 end;
1209 struct btrfs_fs_info *info = extent_root->fs_info;
1210 struct extent_buffer *eb;
1211 struct btrfs_path *path;
1212 struct btrfs_key ins;
1213 struct btrfs_disk_key first;
1214 struct btrfs_extent_item extent_item;
1215 int ret;
1216 int level;
1217 int err = 0;
1218
1219 btrfs_set_stack_extent_refs(&extent_item, 1);
1220 btrfs_set_key_type(&ins, BTRFS_EXTENT_ITEM_KEY);
1221 path = btrfs_alloc_path();
1222
1223 while(1) {
1224 ret = find_first_extent_bit(&info->extent_ins, 0, &start,
1225 &end, EXTENT_LOCKED);
1226 if (ret)
1227 break;
1228
1229 ins.objectid = start;
1230 ins.offset = end + 1 - start;
1231 err = btrfs_insert_item(trans, extent_root, &ins,
1232 &extent_item, sizeof(extent_item));
1233 clear_extent_bits(&info->extent_ins, start, end, EXTENT_LOCKED,
1234 GFP_NOFS);
1235 eb = read_tree_block(extent_root, ins.objectid, ins.offset);
1236 level = btrfs_header_level(eb);
1237 if (level == 0) {
1238 btrfs_item_key(eb, &first, 0);
1239 } else {
1240 btrfs_node_key(eb, &first, 0);
1241 }
1242 err = btrfs_insert_extent_backref(trans, extent_root, path,
1243 start, extent_root->root_key.objectid,
1244 0, level,
1245 btrfs_disk_key_objectid(&first));
1246 BUG_ON(err);
1247 free_extent_buffer(eb);
1248 }
1249 btrfs_free_path(path);
1250 return 0;
1251 }
1252
1253 static int pin_down_bytes(struct btrfs_root *root, u64 bytenr, u32 num_bytes,
1254 int pending)
1255 {
1256 int err = 0;
1257 struct extent_buffer *buf;
1258
1259 if (!pending) {
1260 buf = btrfs_find_tree_block(root, bytenr, num_bytes);
1261 if (buf) {
1262 if (btrfs_buffer_uptodate(buf)) {
1263 u64 transid =
1264 root->fs_info->running_transaction->transid;
1265 if (btrfs_header_generation(buf) ==
1266 transid && !btrfs_header_flag(buf,
1267 BTRFS_HEADER_FLAG_WRITTEN)) {
1268 free_extent_buffer(buf);
1269 return 1;
1270 }
1271 }
1272 free_extent_buffer(buf);
1273 }
1274 update_pinned_extents(root, bytenr, num_bytes, 1);
1275 } else {
1276 set_extent_bits(&root->fs_info->pending_del,
1277 bytenr, bytenr + num_bytes - 1,
1278 EXTENT_LOCKED, GFP_NOFS);
1279 }
1280 BUG_ON(err < 0);
1281 return 0;
1282 }
1283
1284 /*
1285 * remove an extent from the root, returns 0 on success
1286 */
1287 static int __free_extent(struct btrfs_trans_handle *trans, struct btrfs_root
1288 *root, u64 bytenr, u64 num_bytes,
1289 u64 root_objectid, u64 ref_generation,
1290 u64 owner_objectid, u64 owner_offset, int pin,
1291 int mark_free)
1292 {
1293 struct btrfs_path *path;
1294 struct btrfs_key key;
1295 struct btrfs_fs_info *info = root->fs_info;
1296 struct btrfs_extent_ops *ops = info->extent_ops;
1297 struct btrfs_root *extent_root = info->extent_root;
1298 struct extent_buffer *leaf;
1299 int ret;
1300 int extent_slot = 0;
1301 int found_extent = 0;
1302 int num_to_del = 1;
1303 struct btrfs_extent_item *ei;
1304 u32 refs;
1305
1306 key.objectid = bytenr;
1307 btrfs_set_key_type(&key, BTRFS_EXTENT_ITEM_KEY);
1308 key.offset = num_bytes;
1309
1310 path = btrfs_alloc_path();
1311 if (!path)
1312 return -ENOMEM;
1313
1314 ret = lookup_extent_backref(trans, extent_root, path,
1315 bytenr, root_objectid,
1316 ref_generation,
1317 owner_objectid, owner_offset, 1);
1318 if (ret == 0) {
1319 struct btrfs_key found_key;
1320 extent_slot = path->slots[0];
1321 while(extent_slot > 0) {
1322 extent_slot--;
1323 btrfs_item_key_to_cpu(path->nodes[0], &found_key,
1324 extent_slot);
1325 if (found_key.objectid != bytenr)
1326 break;
1327 if (found_key.type == BTRFS_EXTENT_ITEM_KEY &&
1328 found_key.offset == num_bytes) {
1329 found_extent = 1;
1330 break;
1331 }
1332 if (path->slots[0] - extent_slot > 5)
1333 break;
1334 }
1335 if (!found_extent)
1336 ret = btrfs_del_item(trans, extent_root, path);
1337 } else {
1338 btrfs_print_leaf(extent_root, path->nodes[0]);
1339 WARN_ON(1);
1340 printk("Unable to find ref byte nr %llu root %llu "
1341 " gen %llu owner %llu offset %llu\n",
1342 (unsigned long long)bytenr,
1343 (unsigned long long)root_objectid,
1344 (unsigned long long)ref_generation,
1345 (unsigned long long)owner_objectid,
1346 (unsigned long long)owner_offset);
1347 }
1348 if (!found_extent) {
1349 btrfs_release_path(extent_root, path);
1350 ret = btrfs_search_slot(trans, extent_root, &key, path, -1, 1);
1351 if (ret < 0)
1352 return ret;
1353 BUG_ON(ret);
1354 extent_slot = path->slots[0];
1355 }
1356
1357 leaf = path->nodes[0];
1358 ei = btrfs_item_ptr(leaf, extent_slot,
1359 struct btrfs_extent_item);
1360 refs = btrfs_extent_refs(leaf, ei);
1361 BUG_ON(refs == 0);
1362 refs -= 1;
1363 btrfs_set_extent_refs(leaf, ei, refs);
1364
1365 btrfs_mark_buffer_dirty(leaf);
1366
1367 if (refs == 0 && found_extent && path->slots[0] == extent_slot + 1) {
1368 /* if the back ref and the extent are next to each other
1369 * they get deleted below in one shot
1370 */
1371 path->slots[0] = extent_slot;
1372 num_to_del = 2;
1373 } else if (found_extent) {
1374 /* otherwise delete the extent back ref */
1375 ret = btrfs_del_item(trans, extent_root, path);
1376 BUG_ON(ret);
1377 /* if refs are 0, we need to setup the path for deletion */
1378 if (refs == 0) {
1379 btrfs_release_path(extent_root, path);
1380 ret = btrfs_search_slot(trans, extent_root, &key, path,
1381 -1, 1);
1382 if (ret < 0)
1383 return ret;
1384 BUG_ON(ret);
1385 }
1386 }
1387
1388 if (refs == 0) {
1389 u64 super_used;
1390 u64 root_used;
1391
1392 if (pin) {
1393 ret = pin_down_bytes(root, bytenr, num_bytes, 0);
1394 if (ret > 0)
1395 mark_free = 1;
1396 BUG_ON(ret < 0);
1397 }
1398
1399 /* block accounting for super block */
1400 super_used = btrfs_super_bytes_used(&info->super_copy);
1401 btrfs_set_super_bytes_used(&info->super_copy,
1402 super_used - num_bytes);
1403
1404 /* block accounting for root item */
1405 root_used = btrfs_root_used(&root->root_item);
1406 btrfs_set_root_used(&root->root_item,
1407 root_used - num_bytes);
1408 ret = btrfs_del_items(trans, extent_root, path, path->slots[0],
1409 num_to_del);
1410 if (ret)
1411 return ret;
1412
1413 if (ops && ops->free_extent)
1414 ops->free_extent(root, bytenr, num_bytes);
1415
1416 ret = update_block_group(trans, root, bytenr, num_bytes, 0,
1417 mark_free);
1418 BUG_ON(ret);
1419 }
1420 btrfs_free_path(path);
1421 finish_current_insert(trans, extent_root);
1422 return ret;
1423 }
1424
1425 /*
1426 * find all the blocks marked as pending in the radix tree and remove
1427 * them from the extent map
1428 */
1429 static int del_pending_extents(struct btrfs_trans_handle *trans, struct
1430 btrfs_root *extent_root)
1431 {
1432 int ret;
1433 int err = 0;
1434 u64 start;
1435 u64 end;
1436 struct extent_io_tree *pending_del;
1437 struct extent_io_tree *pinned_extents;
1438
1439 pending_del = &extent_root->fs_info->pending_del;
1440 pinned_extents = &extent_root->fs_info->pinned_extents;
1441
1442 while(1) {
1443 ret = find_first_extent_bit(pending_del, 0, &start, &end,
1444 EXTENT_LOCKED);
1445 if (ret)
1446 break;
1447 update_pinned_extents(extent_root, start, end + 1 - start, 1);
1448 clear_extent_bits(pending_del, start, end, EXTENT_LOCKED,
1449 GFP_NOFS);
1450 ret = __free_extent(trans, extent_root,
1451 start, end + 1 - start,
1452 extent_root->root_key.objectid,
1453 0, 0, 0, 0, 0);
1454 if (ret)
1455 err = ret;
1456 }
1457 return err;
1458 }
1459
1460 /*
1461 * remove an extent from the root, returns 0 on success
1462 */
1463 int btrfs_free_extent(struct btrfs_trans_handle *trans, struct btrfs_root
1464 *root, u64 bytenr, u64 num_bytes,
1465 u64 root_objectid, u64 ref_generation,
1466 u64 owner_objectid, u64 owner_offset, int pin)
1467 {
1468 struct btrfs_root *extent_root = root->fs_info->extent_root;
1469 int pending_ret;
1470 int ret;
1471
1472 WARN_ON(num_bytes < root->sectorsize);
1473 if (!root->ref_cows)
1474 ref_generation = 0;
1475
1476 if (root == extent_root) {
1477 pin_down_bytes(root, bytenr, num_bytes, 1);
1478 return 0;
1479 }
1480 ret = __free_extent(trans, root, bytenr, num_bytes, root_objectid,
1481 ref_generation, owner_objectid, owner_offset,
1482 pin, pin == 0);
1483 pending_ret = del_pending_extents(trans, root->fs_info->extent_root);
1484 return ret ? ret : pending_ret;
1485 }
1486
1487 static u64 stripe_align(struct btrfs_root *root, u64 val)
1488 {
1489 u64 mask = ((u64)root->stripesize - 1);
1490 u64 ret = (val + mask) & ~mask;
1491 return ret;
1492 }
1493
1494 /*
1495 * walks the btree of allocated extents and find a hole of a given size.
1496 * The key ins is changed to record the hole:
1497 * ins->objectid == block start
1498 * ins->flags = BTRFS_EXTENT_ITEM_KEY
1499 * ins->offset == number of blocks
1500 * Any available blocks before search_start are skipped.
1501 */
1502 static int noinline find_free_extent(struct btrfs_trans_handle *trans,
1503 struct btrfs_root *orig_root,
1504 u64 num_bytes, u64 empty_size,
1505 u64 search_start, u64 search_end,
1506 u64 hint_byte, struct btrfs_key *ins,
1507 u64 exclude_start, u64 exclude_nr,
1508 int data)
1509 {
1510 int ret;
1511 u64 orig_search_start = search_start;
1512 struct btrfs_root * root = orig_root->fs_info->extent_root;
1513 struct btrfs_fs_info *info = root->fs_info;
1514 u64 total_needed = num_bytes;
1515 struct btrfs_block_group_cache *block_group;
1516 int full_scan = 0;
1517 int wrapped = 0;
1518
1519 WARN_ON(num_bytes < root->sectorsize);
1520 btrfs_set_key_type(ins, BTRFS_EXTENT_ITEM_KEY);
1521
1522 if (search_end == (u64)-1)
1523 search_end = btrfs_super_total_bytes(&info->super_copy);
1524
1525 if (hint_byte) {
1526 block_group = btrfs_lookup_block_group(info, hint_byte);
1527 if (!block_group)
1528 hint_byte = search_start;
1529 block_group = btrfs_find_block_group(root, block_group,
1530 hint_byte, data, 1);
1531 } else {
1532 block_group = btrfs_find_block_group(root,
1533 trans->block_group,
1534 search_start, data, 1);
1535 }
1536
1537 total_needed += empty_size;
1538
1539 check_failed:
1540 if (!block_group) {
1541 block_group = btrfs_lookup_block_group(info, search_start);
1542 if (!block_group)
1543 block_group = btrfs_lookup_block_group(info,
1544 orig_search_start);
1545 }
1546 ret = find_search_start(root, &block_group, &search_start,
1547 total_needed, data);
1548 if (ret)
1549 goto error;
1550
1551 search_start = stripe_align(root, search_start);
1552 ins->objectid = search_start;
1553 ins->offset = num_bytes;
1554
1555 if (ins->objectid + num_bytes >= search_end)
1556 goto enospc;
1557
1558 if (ins->objectid + num_bytes >
1559 block_group->key.objectid + block_group->key.offset) {
1560 search_start = block_group->key.objectid +
1561 block_group->key.offset;
1562 goto new_group;
1563 }
1564
1565 if (test_range_bit(&info->extent_ins, ins->objectid,
1566 ins->objectid + num_bytes -1, EXTENT_LOCKED, 0)) {
1567 search_start = ins->objectid + num_bytes;
1568 goto new_group;
1569 }
1570
1571 if (test_range_bit(&info->pinned_extents, ins->objectid,
1572 ins->objectid + num_bytes -1, EXTENT_DIRTY, 0)) {
1573 search_start = ins->objectid + num_bytes;
1574 goto new_group;
1575 }
1576
1577 if (exclude_nr > 0 && (ins->objectid + num_bytes > exclude_start &&
1578 ins->objectid < exclude_start + exclude_nr)) {
1579 search_start = exclude_start + exclude_nr;
1580 goto new_group;
1581 }
1582
1583 if (!(data & BTRFS_BLOCK_GROUP_DATA)) {
1584 block_group = btrfs_lookup_block_group(info, ins->objectid);
1585 if (block_group)
1586 trans->block_group = block_group;
1587 }
1588 ins->offset = num_bytes;
1589 return 0;
1590
1591 new_group:
1592 if (search_start + num_bytes >= search_end) {
1593 enospc:
1594 search_start = orig_search_start;
1595 if (full_scan) {
1596 ret = -ENOSPC;
1597 goto error;
1598 }
1599 if (wrapped) {
1600 if (!full_scan)
1601 total_needed -= empty_size;
1602 full_scan = 1;
1603 } else
1604 wrapped = 1;
1605 }
1606 block_group = btrfs_lookup_block_group(info, search_start);
1607 cond_resched();
1608 block_group = btrfs_find_block_group(root, block_group,
1609 search_start, data, 0);
1610 goto check_failed;
1611
1612 error:
1613 return ret;
1614 }
1615 /*
1616 * finds a free extent and does all the dirty work required for allocation
1617 * returns the key for the extent through ins, and a tree buffer for
1618 * the first block of the extent through buf.
1619 *
1620 * returns 0 if everything worked, non-zero otherwise.
1621 */
1622 int btrfs_alloc_extent(struct btrfs_trans_handle *trans,
1623 struct btrfs_root *root,
1624 u64 num_bytes, u64 root_objectid, u64 ref_generation,
1625 u64 owner, u64 owner_offset,
1626 u64 empty_size, u64 hint_byte,
1627 u64 search_end, struct btrfs_key *ins, int data)
1628 {
1629 int ret;
1630 int pending_ret;
1631 u64 super_used, root_used;
1632 u64 search_start = 0;
1633 u64 alloc_profile;
1634 struct btrfs_fs_info *info = root->fs_info;
1635 struct btrfs_extent_ops *ops = info->extent_ops;
1636 u32 sizes[2];
1637 struct btrfs_root *extent_root = info->extent_root;
1638 struct btrfs_path *path;
1639 struct btrfs_extent_item *extent_item;
1640 struct btrfs_extent_ref *ref;
1641 struct btrfs_key keys[2];
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 (root == info->chunk_root || info->force_system_allocs) {
1648 alloc_profile = info->avail_system_alloc_bits &
1649 info->system_alloc_profile;
1650 data = BTRFS_BLOCK_GROUP_SYSTEM | alloc_profile;
1651 } else {
1652 alloc_profile = info->avail_metadata_alloc_bits &
1653 info->metadata_alloc_profile;
1654 data = BTRFS_BLOCK_GROUP_METADATA | alloc_profile;
1655 }
1656
1657 if (root->ref_cows) {
1658 if (!(data & BTRFS_BLOCK_GROUP_METADATA)) {
1659 ret = do_chunk_alloc(trans, root->fs_info->extent_root,
1660 num_bytes,
1661 BTRFS_BLOCK_GROUP_METADATA);
1662 BUG_ON(ret);
1663 }
1664 ret = do_chunk_alloc(trans, root->fs_info->extent_root,
1665 num_bytes + 2 * 1024 * 1024, data);
1666 BUG_ON(ret);
1667 }
1668
1669 WARN_ON(num_bytes < root->sectorsize);
1670 if (ops && ops->alloc_extent) {
1671 ret = ops->alloc_extent(root, num_bytes, hint_byte, ins);
1672 } else {
1673 ret = find_free_extent(trans, root, num_bytes, empty_size,
1674 search_start, search_end, hint_byte,
1675 ins, trans->alloc_exclude_start,
1676 trans->alloc_exclude_nr, data);
1677 }
1678 BUG_ON(ret);
1679 if (ret)
1680 return ret;
1681
1682 /* block accounting for super block */
1683 super_used = btrfs_super_bytes_used(&info->super_copy);
1684 btrfs_set_super_bytes_used(&info->super_copy, super_used + num_bytes);
1685
1686 /* block accounting for root item */
1687 root_used = btrfs_root_used(&root->root_item);
1688 btrfs_set_root_used(&root->root_item, root_used + num_bytes);
1689
1690 clear_extent_dirty(&root->fs_info->free_space_cache,
1691 ins->objectid, ins->objectid + ins->offset - 1,
1692 GFP_NOFS);
1693
1694 if (root == extent_root) {
1695 set_extent_bits(&root->fs_info->extent_ins, ins->objectid,
1696 ins->objectid + ins->offset - 1,
1697 EXTENT_LOCKED, GFP_NOFS);
1698 goto update_block;
1699 }
1700
1701 WARN_ON(trans->alloc_exclude_nr);
1702 trans->alloc_exclude_start = ins->objectid;
1703 trans->alloc_exclude_nr = ins->offset;
1704
1705 memcpy(&keys[0], ins, sizeof(*ins));
1706 keys[1].offset = hash_extent_ref(root_objectid, ref_generation,
1707 owner, owner_offset);
1708 keys[1].objectid = ins->objectid;
1709 keys[1].type = BTRFS_EXTENT_REF_KEY;
1710 sizes[0] = sizeof(*extent_item);
1711 sizes[1] = sizeof(*ref);
1712
1713 path = btrfs_alloc_path();
1714 BUG_ON(!path);
1715
1716 ret = btrfs_insert_empty_items(trans, extent_root, path, keys,
1717 sizes, 2);
1718
1719 BUG_ON(ret);
1720 extent_item = btrfs_item_ptr(path->nodes[0], path->slots[0],
1721 struct btrfs_extent_item);
1722 btrfs_set_extent_refs(path->nodes[0], extent_item, 1);
1723 ref = btrfs_item_ptr(path->nodes[0], path->slots[0] + 1,
1724 struct btrfs_extent_ref);
1725
1726 btrfs_set_ref_root(path->nodes[0], ref, root_objectid);
1727 btrfs_set_ref_generation(path->nodes[0], ref, ref_generation);
1728 btrfs_set_ref_objectid(path->nodes[0], ref, owner);
1729 btrfs_set_ref_offset(path->nodes[0], ref, owner_offset);
1730
1731 btrfs_mark_buffer_dirty(path->nodes[0]);
1732
1733 trans->alloc_exclude_start = 0;
1734 trans->alloc_exclude_nr = 0;
1735 btrfs_free_path(path);
1736 finish_current_insert(trans, extent_root);
1737 pending_ret = del_pending_extents(trans, extent_root);
1738
1739 if (ret) {
1740 return ret;
1741 }
1742 if (pending_ret) {
1743 return pending_ret;
1744 }
1745
1746 update_block:
1747 ret = update_block_group(trans, root, ins->objectid, ins->offset, 1, 0);
1748 if (ret) {
1749 printk("update block group failed for %llu %llu\n",
1750 (unsigned long long)ins->objectid,
1751 (unsigned long long)ins->offset);
1752 BUG();
1753 }
1754 return 0;
1755 }
1756
1757 /*
1758 * helper function to allocate a block for a given tree
1759 * returns the tree buffer or NULL.
1760 */
1761 struct extent_buffer *btrfs_alloc_free_block(struct btrfs_trans_handle *trans,
1762 struct btrfs_root *root,
1763 u32 blocksize,
1764 u64 root_objectid, u64 hint,
1765 u64 empty_size)
1766 {
1767 u64 ref_generation;
1768
1769 if (root->ref_cows)
1770 ref_generation = trans->transid;
1771 else
1772 ref_generation = 0;
1773
1774
1775 return __btrfs_alloc_free_block(trans, root, blocksize, root_objectid,
1776 ref_generation, 0, 0, hint, empty_size);
1777 }
1778
1779 /*
1780 * helper function to allocate a block for a given tree
1781 * returns the tree buffer or NULL.
1782 */
1783 struct extent_buffer *__btrfs_alloc_free_block(struct btrfs_trans_handle *trans,
1784 struct btrfs_root *root,
1785 u32 blocksize,
1786 u64 root_objectid,
1787 u64 ref_generation,
1788 u64 first_objectid,
1789 int level,
1790 u64 hint,
1791 u64 empty_size)
1792 {
1793 struct btrfs_key ins;
1794 int ret;
1795 struct extent_buffer *buf;
1796
1797 ret = btrfs_alloc_extent(trans, root, blocksize,
1798 root_objectid, ref_generation,
1799 level, first_objectid, empty_size, hint,
1800 (u64)-1, &ins, 0);
1801 if (ret) {
1802 BUG_ON(ret > 0);
1803 return ERR_PTR(ret);
1804 }
1805 buf = btrfs_find_create_tree_block(root, ins.objectid, blocksize);
1806 if (!buf) {
1807 btrfs_free_extent(trans, root, ins.objectid, blocksize,
1808 root->root_key.objectid, ref_generation,
1809 0, 0, 0);
1810 BUG_ON(1);
1811 return ERR_PTR(-ENOMEM);
1812 }
1813 btrfs_set_buffer_uptodate(buf);
1814 trans->blocks_used++;
1815 return buf;
1816 }
1817
1818 static int noinline drop_leaf_ref(struct btrfs_trans_handle *trans,
1819 struct btrfs_root *root,
1820 struct extent_buffer *leaf)
1821 {
1822 u64 leaf_owner;
1823 u64 leaf_generation;
1824 struct btrfs_key key;
1825 struct btrfs_file_extent_item *fi;
1826 int i;
1827 int nritems;
1828 int ret;
1829
1830 BUG_ON(!btrfs_is_leaf(leaf));
1831 nritems = btrfs_header_nritems(leaf);
1832 leaf_owner = btrfs_header_owner(leaf);
1833 leaf_generation = btrfs_header_generation(leaf);
1834
1835 for (i = 0; i < nritems; i++) {
1836 u64 disk_bytenr;
1837
1838 btrfs_item_key_to_cpu(leaf, &key, i);
1839 if (btrfs_key_type(&key) != BTRFS_EXTENT_DATA_KEY)
1840 continue;
1841 fi = btrfs_item_ptr(leaf, i, struct btrfs_file_extent_item);
1842 if (btrfs_file_extent_type(leaf, fi) ==
1843 BTRFS_FILE_EXTENT_INLINE)
1844 continue;
1845 /*
1846 * FIXME make sure to insert a trans record that
1847 * repeats the snapshot del on crash
1848 */
1849 disk_bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
1850 if (disk_bytenr == 0)
1851 continue;
1852 ret = btrfs_free_extent(trans, root, disk_bytenr,
1853 btrfs_file_extent_disk_num_bytes(leaf, fi),
1854 leaf_owner, leaf_generation,
1855 key.objectid, key.offset, 0);
1856 BUG_ON(ret);
1857 }
1858 return 0;
1859 }
1860
1861 static void noinline reada_walk_down(struct btrfs_root *root,
1862 struct extent_buffer *node,
1863 int slot)
1864 {
1865 u64 bytenr;
1866 u64 last = 0;
1867 u32 nritems;
1868 u32 refs;
1869 u32 blocksize;
1870 int ret;
1871 int i;
1872 int level;
1873 int skipped = 0;
1874
1875 nritems = btrfs_header_nritems(node);
1876 level = btrfs_header_level(node);
1877 if (level)
1878 return;
1879
1880 for (i = slot; i < nritems && skipped < 32; i++) {
1881 bytenr = btrfs_node_blockptr(node, i);
1882 if (last && ((bytenr > last && bytenr - last > 32 * 1024) ||
1883 (last > bytenr && last - bytenr > 32 * 1024))) {
1884 skipped++;
1885 continue;
1886 }
1887 blocksize = btrfs_level_size(root, level - 1);
1888 if (i != slot) {
1889 ret = lookup_extent_ref(NULL, root, bytenr,
1890 blocksize, &refs);
1891 BUG_ON(ret);
1892 if (refs != 1) {
1893 skipped++;
1894 continue;
1895 }
1896 }
1897 mutex_unlock(&root->fs_info->fs_mutex);
1898 ret = readahead_tree_block(root, bytenr, blocksize);
1899 last = bytenr + blocksize;
1900 cond_resched();
1901 mutex_lock(&root->fs_info->fs_mutex);
1902 if (ret)
1903 break;
1904 }
1905 }
1906
1907 /*
1908 * helper function for drop_snapshot, this walks down the tree dropping ref
1909 * counts as it goes.
1910 */
1911 static int noinline walk_down_tree(struct btrfs_trans_handle *trans,
1912 struct btrfs_root *root,
1913 struct btrfs_path *path, int *level)
1914 {
1915 u64 root_owner;
1916 u64 root_gen;
1917 u64 bytenr;
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 blocksize = btrfs_level_size(root, *level - 1);
1955 ret = lookup_extent_ref(trans, root, bytenr, blocksize, &refs);
1956 BUG_ON(ret);
1957 if (refs != 1) {
1958 parent = path->nodes[*level];
1959 root_owner = btrfs_header_owner(parent);
1960 root_gen = btrfs_header_generation(parent);
1961 path->slots[*level]++;
1962 ret = btrfs_free_extent(trans, root, bytenr,
1963 blocksize, root_owner,
1964 root_gen, 0, 0, 1);
1965 BUG_ON(ret);
1966 continue;
1967 }
1968 next = btrfs_find_tree_block(root, bytenr, blocksize);
1969 if (!next || !btrfs_buffer_uptodate(next)) {
1970 free_extent_buffer(next);
1971 reada_walk_down(root, cur, path->slots[*level]);
1972 mutex_unlock(&root->fs_info->fs_mutex);
1973 next = read_tree_block(root, bytenr, blocksize);
1974 mutex_lock(&root->fs_info->fs_mutex);
1975
1976 /* we dropped the lock, check one more time */
1977 ret = lookup_extent_ref(trans, root, bytenr,
1978 blocksize, &refs);
1979 BUG_ON(ret);
1980 if (refs != 1) {
1981 parent = path->nodes[*level];
1982 root_owner = btrfs_header_owner(parent);
1983 root_gen = btrfs_header_generation(parent);
1984
1985 path->slots[*level]++;
1986 free_extent_buffer(next);
1987 ret = btrfs_free_extent(trans, root, bytenr,
1988 blocksize,
1989 root_owner,
1990 root_gen, 0, 0, 1);
1991 BUG_ON(ret);
1992 continue;
1993 }
1994 }
1995 WARN_ON(*level <= 0);
1996 if (path->nodes[*level-1])
1997 free_extent_buffer(path->nodes[*level-1]);
1998 path->nodes[*level-1] = next;
1999 *level = btrfs_header_level(next);
2000 path->slots[*level] = 0;
2001 }
2002 out:
2003 WARN_ON(*level < 0);
2004 WARN_ON(*level >= BTRFS_MAX_LEVEL);
2005
2006 if (path->nodes[*level] == root->node) {
2007 root_owner = root->root_key.objectid;
2008 parent = path->nodes[*level];
2009 } else {
2010 parent = path->nodes[*level + 1];
2011 root_owner = btrfs_header_owner(parent);
2012 }
2013
2014 root_gen = btrfs_header_generation(parent);
2015 ret = btrfs_free_extent(trans, root, path->nodes[*level]->start,
2016 path->nodes[*level]->len,
2017 root_owner, root_gen, 0, 0, 1);
2018 free_extent_buffer(path->nodes[*level]);
2019 path->nodes[*level] = NULL;
2020 *level += 1;
2021 BUG_ON(ret);
2022 return 0;
2023 }
2024
2025 /*
2026 * helper for dropping snapshots. This walks back up the tree in the path
2027 * to find the first node higher up where we haven't yet gone through
2028 * all the slots
2029 */
2030 static int noinline walk_up_tree(struct btrfs_trans_handle *trans,
2031 struct btrfs_root *root,
2032 struct btrfs_path *path, int *level)
2033 {
2034 u64 root_owner;
2035 u64 root_gen;
2036 struct btrfs_root_item *root_item = &root->root_item;
2037 int i;
2038 int slot;
2039 int ret;
2040
2041 for(i = *level; i < BTRFS_MAX_LEVEL - 1 && path->nodes[i]; i++) {
2042 slot = path->slots[i];
2043 if (slot < btrfs_header_nritems(path->nodes[i]) - 1) {
2044 struct extent_buffer *node;
2045 struct btrfs_disk_key disk_key;
2046 node = path->nodes[i];
2047 path->slots[i]++;
2048 *level = i;
2049 WARN_ON(*level == 0);
2050 btrfs_node_key(node, &disk_key, path->slots[i]);
2051 memcpy(&root_item->drop_progress,
2052 &disk_key, sizeof(disk_key));
2053 root_item->drop_level = i;
2054 return 0;
2055 } else {
2056 if (path->nodes[*level] == root->node) {
2057 root_owner = root->root_key.objectid;
2058 root_gen =
2059 btrfs_header_generation(path->nodes[*level]);
2060 } else {
2061 struct extent_buffer *node;
2062 node = path->nodes[*level + 1];
2063 root_owner = btrfs_header_owner(node);
2064 root_gen = btrfs_header_generation(node);
2065 }
2066 ret = btrfs_free_extent(trans, root,
2067 path->nodes[*level]->start,
2068 path->nodes[*level]->len,
2069 root_owner, root_gen, 0, 0, 1);
2070 BUG_ON(ret);
2071 free_extent_buffer(path->nodes[*level]);
2072 path->nodes[*level] = NULL;
2073 *level = i + 1;
2074 }
2075 }
2076 return 1;
2077 }
2078
2079 /*
2080 * drop the reference count on the tree rooted at 'snap'. This traverses
2081 * the tree freeing any blocks that have a ref count of zero after being
2082 * decremented.
2083 */
2084 int btrfs_drop_snapshot(struct btrfs_trans_handle *trans, struct btrfs_root
2085 *root)
2086 {
2087 int ret = 0;
2088 int wret;
2089 int level;
2090 struct btrfs_path *path;
2091 int i;
2092 int orig_level;
2093 struct btrfs_root_item *root_item = &root->root_item;
2094
2095 path = btrfs_alloc_path();
2096 BUG_ON(!path);
2097
2098 level = btrfs_header_level(root->node);
2099 orig_level = level;
2100 if (btrfs_disk_key_objectid(&root_item->drop_progress) == 0) {
2101 path->nodes[level] = root->node;
2102 extent_buffer_get(root->node);
2103 path->slots[level] = 0;
2104 } else {
2105 struct btrfs_key key;
2106 struct btrfs_disk_key found_key;
2107 struct extent_buffer *node;
2108
2109 btrfs_disk_key_to_cpu(&key, &root_item->drop_progress);
2110 level = root_item->drop_level;
2111 path->lowest_level = level;
2112 wret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
2113 if (wret < 0) {
2114 ret = wret;
2115 goto out;
2116 }
2117 node = path->nodes[level];
2118 btrfs_node_key(node, &found_key, path->slots[level]);
2119 WARN_ON(memcmp(&found_key, &root_item->drop_progress,
2120 sizeof(found_key)));
2121 }
2122 while(1) {
2123 wret = walk_down_tree(trans, root, path, &level);
2124 if (wret < 0)
2125 ret = wret;
2126 if (wret != 0)
2127 break;
2128
2129 wret = walk_up_tree(trans, root, path, &level);
2130 if (wret < 0)
2131 ret = wret;
2132 if (wret != 0)
2133 break;
2134 /*
2135 ret = -EAGAIN;
2136 break;
2137 */
2138 }
2139 for (i = 0; i <= orig_level; i++) {
2140 if (path->nodes[i]) {
2141 free_extent_buffer(path->nodes[i]);
2142 path->nodes[i] = NULL;
2143 }
2144 }
2145 out:
2146 btrfs_free_path(path);
2147 return ret;
2148 }
2149
2150 int btrfs_free_block_groups(struct btrfs_fs_info *info)
2151 {
2152 u64 start;
2153 u64 end;
2154 u64 ptr;
2155 int ret;
2156 while(1) {
2157 ret = find_first_extent_bit(&info->block_group_cache, 0,
2158 &start, &end, (unsigned int)-1);
2159 if (ret)
2160 break;
2161 ret = get_state_private(&info->block_group_cache, start, &ptr);
2162 if (!ret)
2163 kfree((void *)(unsigned long)ptr);
2164 clear_extent_bits(&info->block_group_cache, start,
2165 end, (unsigned int)-1, GFP_NOFS);
2166 }
2167 while(1) {
2168 ret = find_first_extent_bit(&info->free_space_cache, 0,
2169 &start, &end, EXTENT_DIRTY);
2170 if (ret)
2171 break;
2172 clear_extent_dirty(&info->free_space_cache, start,
2173 end, GFP_NOFS);
2174 }
2175 return 0;
2176 }
2177
2178 int find_first_block_group(struct btrfs_root *root, struct btrfs_path *path,
2179 struct btrfs_key *key)
2180 {
2181 int ret;
2182 struct btrfs_key found_key;
2183 struct extent_buffer *leaf;
2184 int slot;
2185
2186 ret = btrfs_search_slot(NULL, root, key, path, 0, 0);
2187 if (ret < 0)
2188 return ret;
2189 while(1) {
2190 slot = path->slots[0];
2191 leaf = path->nodes[0];
2192 if (slot >= btrfs_header_nritems(leaf)) {
2193 ret = btrfs_next_leaf(root, path);
2194 if (ret == 0)
2195 continue;
2196 if (ret < 0)
2197 goto error;
2198 break;
2199 }
2200 btrfs_item_key_to_cpu(leaf, &found_key, slot);
2201
2202 if (found_key.objectid >= key->objectid &&
2203 found_key.type == BTRFS_BLOCK_GROUP_ITEM_KEY)
2204 return 0;
2205 path->slots[0]++;
2206 }
2207 ret = -ENOENT;
2208 error:
2209 return ret;
2210 }
2211
2212 int btrfs_read_block_groups(struct btrfs_root *root)
2213 {
2214 struct btrfs_path *path;
2215 int ret;
2216 int bit;
2217 struct btrfs_block_group_cache *cache;
2218 struct btrfs_fs_info *info = root->fs_info;
2219 struct btrfs_space_info *space_info;
2220 struct extent_io_tree *block_group_cache;
2221 struct btrfs_key key;
2222 struct btrfs_key found_key;
2223 struct extent_buffer *leaf;
2224
2225 block_group_cache = &info->block_group_cache;
2226
2227 root = info->extent_root;
2228 key.objectid = 0;
2229 key.offset = 0;
2230 btrfs_set_key_type(&key, BTRFS_BLOCK_GROUP_ITEM_KEY);
2231 path = btrfs_alloc_path();
2232 if (!path)
2233 return -ENOMEM;
2234
2235 while(1) {
2236 ret = find_first_block_group(root, path, &key);
2237 if (ret > 0) {
2238 ret = 0;
2239 goto error;
2240 }
2241 if (ret != 0) {
2242 goto error;
2243 }
2244 leaf = path->nodes[0];
2245 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
2246 cache = kmalloc(sizeof(*cache), GFP_NOFS);
2247 if (!cache) {
2248 ret = -ENOMEM;
2249 break;
2250 }
2251
2252 read_extent_buffer(leaf, &cache->item,
2253 btrfs_item_ptr_offset(leaf, path->slots[0]),
2254 sizeof(cache->item));
2255 memcpy(&cache->key, &found_key, sizeof(found_key));
2256 cache->cached = 0;
2257 cache->pinned = 0;
2258 key.objectid = found_key.objectid + found_key.offset;
2259 btrfs_release_path(root, path);
2260 cache->flags = btrfs_block_group_flags(&cache->item);
2261 bit = 0;
2262 if (cache->flags & BTRFS_BLOCK_GROUP_DATA) {
2263 bit = BLOCK_GROUP_DATA;
2264 } else if (cache->flags & BTRFS_BLOCK_GROUP_SYSTEM) {
2265 bit = BLOCK_GROUP_SYSTEM;
2266 } else if (cache->flags & BTRFS_BLOCK_GROUP_METADATA) {
2267 bit = BLOCK_GROUP_METADATA;
2268 }
2269 set_avail_alloc_bits(info, cache->flags);
2270
2271 ret = update_space_info(info, cache->flags, found_key.offset,
2272 btrfs_block_group_used(&cache->item),
2273 &space_info);
2274 BUG_ON(ret);
2275 cache->space_info = space_info;
2276
2277 /* use EXTENT_LOCKED to prevent merging */
2278 set_extent_bits(block_group_cache, found_key.objectid,
2279 found_key.objectid + found_key.offset - 1,
2280 bit | EXTENT_LOCKED, GFP_NOFS);
2281 set_state_private(block_group_cache, found_key.objectid,
2282 (unsigned long)cache);
2283
2284 if (key.objectid >=
2285 btrfs_super_total_bytes(&info->super_copy))
2286 break;
2287 }
2288 ret = 0;
2289 error:
2290 btrfs_free_path(path);
2291 return ret;
2292 }
2293
2294 int btrfs_make_block_group(struct btrfs_trans_handle *trans,
2295 struct btrfs_root *root, u64 bytes_used,
2296 u64 type, u64 chunk_tree, u64 chunk_objectid,
2297 u64 size)
2298 {
2299 int ret;
2300 int bit = 0;
2301 struct btrfs_root *extent_root;
2302 struct btrfs_block_group_cache *cache;
2303 struct extent_io_tree *block_group_cache;
2304
2305 extent_root = root->fs_info->extent_root;
2306 block_group_cache = &root->fs_info->block_group_cache;
2307
2308 cache = kzalloc(sizeof(*cache), GFP_NOFS);
2309 BUG_ON(!cache);
2310 cache->key.objectid = chunk_objectid;
2311 cache->key.offset = size;
2312 btrfs_set_key_type(&cache->key, BTRFS_BLOCK_GROUP_ITEM_KEY);
2313 btrfs_set_block_group_used(&cache->item, bytes_used);
2314 btrfs_set_block_group_chunk_tree(&cache->item, chunk_tree);
2315 btrfs_set_block_group_chunk_objectid(&cache->item, chunk_objectid);
2316 cache->flags = type;
2317 btrfs_set_block_group_flags(&cache->item, type);
2318
2319 ret = update_space_info(root->fs_info, cache->flags, size, bytes_used,
2320 &cache->space_info);
2321 BUG_ON(ret);
2322
2323 bit = block_group_state_bits(type);
2324 set_extent_bits(block_group_cache, chunk_objectid,
2325 chunk_objectid + size - 1,
2326 bit | EXTENT_LOCKED, GFP_NOFS);
2327 set_state_private(block_group_cache, chunk_objectid,
2328 (unsigned long)cache);
2329
2330 ret = btrfs_insert_item(trans, extent_root, &cache->key, &cache->item,
2331 sizeof(cache->item));
2332 BUG_ON(ret);
2333
2334 finish_current_insert(trans, extent_root);
2335 ret = del_pending_extents(trans, extent_root);
2336 BUG_ON(ret);
2337 set_avail_alloc_bits(extent_root->fs_info, type);
2338 return 0;
2339 }
2340
2341 u64 btrfs_hash_extent_ref(u64 root_objectid, u64 ref_generation,
2342 u64 owner, u64 owner_offset)
2343 {
2344 return hash_extent_ref(root_objectid, ref_generation,
2345 owner, owner_offset);
2346 }
2347
2348 int btrfs_update_block_group(struct btrfs_trans_handle *trans,
2349 struct btrfs_root *root,
2350 u64 bytenr, u64 num_bytes, int alloc,
2351 int mark_free)
2352 {
2353 return update_block_group(trans, root, bytenr, num_bytes,
2354 alloc, mark_free);
2355 }
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