projects / deliverable / linux.git / blob
? search:
summary | shortlog | log | commit | commitdiff | tree
blame | history | raw | HEAD
Btrfs: Reorder extent back refs to differentiate btree blocks from file data
[deliverable/linux.git] / fs / btrfs / extent-tree.c
1 /*
2 * Copyright (C) 2007 Oracle. All rights reserved.
3 *
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU General Public
6 * License v2 as published by the Free Software Foundation.
7 *
8 * This program is distributed in the hope that it will be useful,
9 * but WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
11 * General Public License for more details.
12 *
13 * You should have received a copy of the GNU General Public
14 * License along with this program; if not, write to the
15 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
16 * Boston, MA 021110-1307, USA.
17 */
18
19 #include <linux/sched.h>
20 #include <linux/crc32c.h>
21 #include "hash.h"
22 #include "ctree.h"
23 #include "disk-io.h"
24 #include "print-tree.h"
25 #include "transaction.h"
26
27 #define BLOCK_GROUP_DATA EXTENT_WRITEBACK
28 #define BLOCK_GROUP_METADATA EXTENT_UPTODATE
29 #define BLOCK_GROUP_DIRTY EXTENT_DIRTY
30
31 static int finish_current_insert(struct btrfs_trans_handle *trans, struct
32 btrfs_root *extent_root);
33 static int del_pending_extents(struct btrfs_trans_handle *trans, struct
34 btrfs_root *extent_root);
35
36 static int cache_block_group(struct btrfs_root *root,
37 struct btrfs_block_group_cache *block_group)
38 {
39 struct btrfs_path *path;
40 int ret;
41 struct btrfs_key key;
42 struct extent_buffer *leaf;
43 struct extent_map_tree *free_space_cache;
44 int slot;
45 u64 last = 0;
46 u64 hole_size;
47 u64 first_free;
48 int found = 0;
49
50 if (!block_group)
51 return 0;
52
53 root = root->fs_info->extent_root;
54 free_space_cache = &root->fs_info->free_space_cache;
55
56 if (block_group->cached)
57 return 0;
58
59 path = btrfs_alloc_path();
60 if (!path)
61 return -ENOMEM;
62
63 path->reada = 2;
64 first_free = block_group->key.objectid;
65 key.objectid = block_group->key.objectid;
66 key.offset = 0;
67
68 btrfs_set_key_type(&key, BTRFS_EXTENT_ITEM_KEY);
69 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
70
71 if (ret < 0)
72 return ret;
73
74 if (ret && path->slots[0] > 0)
75 path->slots[0]--;
76
77 while(1) {
78 leaf = path->nodes[0];
79 slot = path->slots[0];
80 if (slot >= btrfs_header_nritems(leaf)) {
81 ret = btrfs_next_leaf(root, path);
82 if (ret < 0)
83 goto err;
84 if (ret == 0) {
85 continue;
86 } else {
87 break;
88 }
89 }
90
91 btrfs_item_key_to_cpu(leaf, &key, slot);
92 if (key.objectid < block_group->key.objectid) {
93 if (btrfs_key_type(&key) != BTRFS_EXTENT_REF_KEY &&
94 key.objectid + key.offset > first_free)
95 first_free = key.objectid + key.offset;
96 goto next;
97 }
98
99 if (key.objectid >= block_group->key.objectid +
100 block_group->key.offset) {
101 break;
102 }
103
104 if (btrfs_key_type(&key) == BTRFS_EXTENT_ITEM_KEY) {
105 if (!found) {
106 last = first_free;
107 found = 1;
108 }
109 if (key.objectid > last) {
110 hole_size = key.objectid - last;
111 set_extent_dirty(free_space_cache, last,
112 last + hole_size - 1,
113 GFP_NOFS);
114 }
115 last = key.objectid + key.offset;
116 }
117 next:
118 path->slots[0]++;
119 }
120
121 if (!found)
122 last = first_free;
123 if (block_group->key.objectid +
124 block_group->key.offset > last) {
125 hole_size = block_group->key.objectid +
126 block_group->key.offset - last;
127 set_extent_dirty(free_space_cache, last,
128 last + hole_size - 1, GFP_NOFS);
129 }
130 block_group->cached = 1;
131 err:
132 btrfs_free_path(path);
133 return 0;
134 }
135
136 struct btrfs_block_group_cache *btrfs_lookup_block_group(struct
137 btrfs_fs_info *info,
138 u64 bytenr)
139 {
140 struct extent_map_tree *block_group_cache;
141 struct btrfs_block_group_cache *block_group = NULL;
142 u64 ptr;
143 u64 start;
144 u64 end;
145 int ret;
146
147 block_group_cache = &info->block_group_cache;
148 ret = find_first_extent_bit(block_group_cache,
149 bytenr, &start, &end,
150 BLOCK_GROUP_DATA | BLOCK_GROUP_METADATA);
151 if (ret) {
152 return NULL;
153 }
154 ret = get_state_private(block_group_cache, start, &ptr);
155 if (ret)
156 return NULL;
157
158 block_group = (struct btrfs_block_group_cache *)(unsigned long)ptr;
159 if (block_group->key.objectid <= bytenr && bytenr <
160 block_group->key.objectid + block_group->key.offset)
161 return block_group;
162 return NULL;
163 }
164 static u64 find_search_start(struct btrfs_root *root,
165 struct btrfs_block_group_cache **cache_ret,
166 u64 search_start, int num,
167 int data, int full_scan)
168 {
169 int ret;
170 struct btrfs_block_group_cache *cache = *cache_ret;
171 u64 last;
172 u64 start = 0;
173 u64 end = 0;
174 u64 cache_miss = 0;
175 int wrapped = 0;
176
177 if (!cache) {
178 goto out;
179 }
180 again:
181 ret = cache_block_group(root, cache);
182 if (ret)
183 goto out;
184
185 last = max(search_start, cache->key.objectid);
186
187 while(1) {
188 ret = find_first_extent_bit(&root->fs_info->free_space_cache,
189 last, &start, &end, EXTENT_DIRTY);
190 if (ret) {
191 if (!cache_miss)
192 cache_miss = last;
193 goto new_group;
194 }
195
196 start = max(last, start);
197 last = end + 1;
198 if (last - start < num) {
199 if (last == cache->key.objectid + cache->key.offset)
200 cache_miss = start;
201 continue;
202 }
203 if (data != BTRFS_BLOCK_GROUP_MIXED &&
204 start + num > cache->key.objectid + cache->key.offset)
205 goto new_group;
206 return start;
207 }
208 out:
209 cache = btrfs_lookup_block_group(root->fs_info, search_start);
210 if (!cache) {
211 printk("Unable to find block group for %Lu\n",
212 search_start);
213 WARN_ON(1);
214 return search_start;
215 }
216 return search_start;
217
218 new_group:
219 last = cache->key.objectid + cache->key.offset;
220 wrapped:
221 cache = btrfs_lookup_block_group(root->fs_info, last);
222 if (!cache) {
223 no_cache:
224 if (!wrapped) {
225 wrapped = 1;
226 last = search_start;
227 data = BTRFS_BLOCK_GROUP_MIXED;
228 goto wrapped;
229 }
230 goto out;
231 }
232 if (cache_miss && !cache->cached) {
233 cache_block_group(root, cache);
234 last = cache_miss;
235 cache = btrfs_lookup_block_group(root->fs_info, last);
236 }
237 cache = btrfs_find_block_group(root, cache, last, data, 0);
238 if (!cache)
239 goto no_cache;
240 *cache_ret = cache;
241 cache_miss = 0;
242 goto again;
243 }
244
245 static u64 div_factor(u64 num, int factor)
246 {
247 if (factor == 10)
248 return num;
249 num *= factor;
250 do_div(num, 10);
251 return num;
252 }
253
254 struct btrfs_block_group_cache *btrfs_find_block_group(struct btrfs_root *root,
255 struct btrfs_block_group_cache
256 *hint, u64 search_start,
257 int data, int owner)
258 {
259 struct btrfs_block_group_cache *cache;
260 struct extent_map_tree *block_group_cache;
261 struct btrfs_block_group_cache *found_group = NULL;
262 struct btrfs_fs_info *info = root->fs_info;
263 u64 used;
264 u64 last = 0;
265 u64 hint_last;
266 u64 start;
267 u64 end;
268 u64 free_check;
269 u64 ptr;
270 int bit;
271 int ret;
272 int full_search = 0;
273 int factor = 8;
274 int data_swap = 0;
275
276 block_group_cache = &info->block_group_cache;
277
278 if (!owner)
279 factor = 8;
280
281 if (data == BTRFS_BLOCK_GROUP_MIXED) {
282 bit = BLOCK_GROUP_DATA | BLOCK_GROUP_METADATA;
283 factor = 10;
284 } else if (data)
285 bit = BLOCK_GROUP_DATA;
286 else
287 bit = BLOCK_GROUP_METADATA;
288
289 if (search_start) {
290 struct btrfs_block_group_cache *shint;
291 shint = btrfs_lookup_block_group(info, search_start);
292 if (shint && (shint->data == data ||
293 shint->data == BTRFS_BLOCK_GROUP_MIXED)) {
294 used = btrfs_block_group_used(&shint->item);
295 if (used + shint->pinned <
296 div_factor(shint->key.offset, factor)) {
297 return shint;
298 }
299 }
300 }
301 if (hint && (hint->data == data ||
302 hint->data == BTRFS_BLOCK_GROUP_MIXED)) {
303 used = btrfs_block_group_used(&hint->item);
304 if (used + hint->pinned <
305 div_factor(hint->key.offset, factor)) {
306 return hint;
307 }
308 last = hint->key.objectid + hint->key.offset;
309 hint_last = last;
310 } else {
311 if (hint)
312 hint_last = max(hint->key.objectid, search_start);
313 else
314 hint_last = search_start;
315
316 last = hint_last;
317 }
318 again:
319 while(1) {
320 ret = find_first_extent_bit(block_group_cache, last,
321 &start, &end, bit);
322 if (ret)
323 break;
324
325 ret = get_state_private(block_group_cache, start, &ptr);
326 if (ret)
327 break;
328
329 cache = (struct btrfs_block_group_cache *)(unsigned long)ptr;
330 last = cache->key.objectid + cache->key.offset;
331 used = btrfs_block_group_used(&cache->item);
332
333 if (full_search)
334 free_check = cache->key.offset;
335 else
336 free_check = div_factor(cache->key.offset, factor);
337 if (used + cache->pinned < free_check) {
338 found_group = cache;
339 goto found;
340 }
341 cond_resched();
342 }
343 if (!full_search) {
344 last = search_start;
345 full_search = 1;
346 goto again;
347 }
348 if (!data_swap) {
349 data_swap = 1;
350 bit = BLOCK_GROUP_DATA | BLOCK_GROUP_METADATA;
351 last = search_start;
352 goto again;
353 }
354 found:
355 return found_group;
356 }
357
358 static u64 hash_extent_ref(u64 root_objectid, u64 ref_generation,
359 u64 owner, u64 owner_offset)
360 {
361 u32 high_crc = ~(u32)0;
362 u32 low_crc = ~(u32)0;
363 __le64 lenum;
364
365 lenum = cpu_to_le64(root_objectid);
366 high_crc = crc32c(high_crc, &lenum, sizeof(lenum));
367 lenum = cpu_to_le64(ref_generation);
368 low_crc = crc32c(low_crc, &lenum, sizeof(lenum));
369
370 #if 0
371 lenum = cpu_to_le64(owner);
372 low_crc = crc32c(low_crc, &lenum, sizeof(lenum));
373 lenum = cpu_to_le64(owner_offset);
374 low_crc = crc32c(low_crc, &lenum, sizeof(lenum));
375 #endif
376 return ((u64)high_crc << 32) | (u64)low_crc;
377 }
378
379 static int match_extent_ref(struct extent_buffer *leaf,
380 struct btrfs_extent_ref *disk_ref,
381 struct btrfs_extent_ref *cpu_ref)
382 {
383 int ret;
384 int len;
385
386 if (cpu_ref->objectid)
387 len = sizeof(*cpu_ref);
388 else
389 len = 2 * sizeof(u64);
390 ret = memcmp_extent_buffer(leaf, cpu_ref, (unsigned long)disk_ref,
391 len);
392 return ret == 0;
393 }
394
395 static int lookup_extent_backref(struct btrfs_trans_handle *trans,
396 struct btrfs_root *root,
397 struct btrfs_path *path, u64 bytenr,
398 u64 root_objectid, u64 ref_generation,
399 u64 owner, u64 owner_offset, int del)
400 {
401 u64 hash;
402 struct btrfs_key key;
403 struct btrfs_key found_key;
404 struct btrfs_extent_ref ref;
405 struct extent_buffer *leaf;
406 struct btrfs_extent_ref *disk_ref;
407 int ret;
408 int ret2;
409
410 btrfs_set_stack_ref_root(&ref, root_objectid);
411 btrfs_set_stack_ref_generation(&ref, ref_generation);
412 btrfs_set_stack_ref_objectid(&ref, owner);
413 btrfs_set_stack_ref_offset(&ref, owner_offset);
414
415 hash = hash_extent_ref(root_objectid, ref_generation, owner,
416 owner_offset);
417 key.offset = hash;
418 key.objectid = bytenr;
419 key.type = BTRFS_EXTENT_REF_KEY;
420
421 while (1) {
422 ret = btrfs_search_slot(trans, root, &key, path,
423 del ? -1 : 0, del);
424 if (ret < 0)
425 goto out;
426 leaf = path->nodes[0];
427 if (ret != 0) {
428 u32 nritems = btrfs_header_nritems(leaf);
429 if (path->slots[0] >= nritems) {
430 ret2 = btrfs_next_leaf(root, path);
431 if (ret2)
432 goto out;
433 leaf = path->nodes[0];
434 }
435 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
436 if (found_key.objectid != bytenr ||
437 found_key.type != BTRFS_EXTENT_REF_KEY)
438 goto out;
439 key.offset = found_key.offset;
440 if (del) {
441 btrfs_release_path(root, path);
442 continue;
443 }
444 }
445 disk_ref = btrfs_item_ptr(path->nodes[0],
446 path->slots[0],
447 struct btrfs_extent_ref);
448 if (match_extent_ref(path->nodes[0], disk_ref, &ref)) {
449 ret = 0;
450 goto out;
451 }
452 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
453 key.offset = found_key.offset + 1;
454 btrfs_release_path(root, path);
455 }
456 out:
457 return ret;
458 }
459
460 /*
461 * Back reference rules. Back refs have three main goals:
462 *
463 * 1) differentiate between all holders of references to an extent so that
464 * when a reference is dropped we can make sure it was a valid reference
465 * before freeing the extent.
466 *
467 * 2) Provide enough information to quickly find the holders of an extent
468 * if we notice a given block is corrupted or bad.
469 *
470 * 3) Make it easy to migrate blocks for FS shrinking or storage pool
471 * maintenance. This is actually the same as #2, but with a slightly
472 * different use case.
473 *
474 * File extents can be referenced by:
475 *
476 * - multiple snapshots, subvolumes, or different generations in one subvol
477 * - different files inside a single subvolume (in theory, not implemented yet)
478 * - different offsets inside a file (bookend extents in file.c)
479 *
480 * The extent ref structure has fields for:
481 *
482 * - Objectid of the subvolume root
483 * - Generation number of the tree holding the reference
484 * - objectid of the file holding the reference
485 * - offset in the file corresponding to the key holding the reference
486 *
487 * When a file extent is allocated the fields are filled in:
488 * (root_key.objectid, trans->transid, inode objectid, offset in file)
489 *
490 * When a leaf is cow'd new references are added for every file extent found
491 * in the leaf. It looks the same as the create case, but trans->transid
492 * will be different when the block is cow'd.
493 *
494 * (root_key.objectid, trans->transid, inode objectid, offset in file)
495 *
496 * When a file extent is removed either during snapshot deletion or file
497 * truncation, the corresponding back reference is found
498 * by searching for:
499 *
500 * (btrfs_header_owner(leaf), btrfs_header_generation(leaf),
501 * inode objectid, offset in file)
502 *
503 * Btree extents can be referenced by:
504 *
505 * - Different subvolumes
506 * - Different generations of the same subvolume
507 *
508 * Storing sufficient information for a full reverse mapping of a btree
509 * block would require storing the lowest key of the block in the backref,
510 * and it would require updating that lowest key either before write out or
511 * every time it changed. Instead, the objectid of the lowest key is stored
512 * along with the level of the tree block. This provides a hint
513 * about where in the btree the block can be found. Searches through the
514 * btree only need to look for a pointer to that block, so they stop one
515 * level higher than the level recorded in the backref.
516 *
517 * Some btrees do not do reference counting on their extents. These
518 * include the extent tree and the tree of tree roots. Backrefs for these
519 * trees always have a generation of zero.
520 *
521 * When a tree block is created, back references are inserted:
522 *
523 * (root->root_key.objectid, trans->transid or zero, level, lowest_key_objectid)
524 *
525 * When a tree block is cow'd in a reference counted root,
526 * new back references are added for all the blocks it points to.
527 * These are of the form (trans->transid will have increased since creation):
528 *
529 * (root->root_key.objectid, trans->transid, level, lowest_key_objectid)
530 *
531 * Because the lowest_key_objectid and the level are just hints
532 * they are not used when backrefs are deleted. When a backref is deleted:
533 *
534 * if backref was for a tree root:
535 * root_objectid = root->root_key.objectid
536 * else
537 * root_objectid = btrfs_header_owner(parent)
538 *
539 * (root_objectid, btrfs_header_generation(parent) or zero, 0, 0)
540 *
541 * Back Reference Key hashing:
542 *
543 * Back references have four fields, each 64 bits long. Unfortunately,
544 * This is hashed into a single 64 bit number and placed into the key offset.
545 * The key objectid corresponds to the first byte in the extent, and the
546 * key type is set to BTRFS_EXTENT_REF_KEY
547 */
548 int btrfs_insert_extent_backref(struct btrfs_trans_handle *trans,
549 struct btrfs_root *root,
550 struct btrfs_path *path, u64 bytenr,
551 u64 root_objectid, u64 ref_generation,
552 u64 owner, u64 owner_offset)
553 {
554 u64 hash;
555 struct btrfs_key key;
556 struct btrfs_extent_ref ref;
557 struct btrfs_extent_ref *disk_ref;
558 int ret;
559
560 btrfs_set_stack_ref_root(&ref, root_objectid);
561 btrfs_set_stack_ref_generation(&ref, ref_generation);
562 btrfs_set_stack_ref_objectid(&ref, owner);
563 btrfs_set_stack_ref_offset(&ref, owner_offset);
564
565 hash = hash_extent_ref(root_objectid, ref_generation, owner,
566 owner_offset);
567 key.offset = hash;
568 key.objectid = bytenr;
569 key.type = BTRFS_EXTENT_REF_KEY;
570
571 ret = btrfs_insert_empty_item(trans, root, path, &key, sizeof(ref));
572 while (ret == -EEXIST) {
573 disk_ref = btrfs_item_ptr(path->nodes[0], path->slots[0],
574 struct btrfs_extent_ref);
575 if (match_extent_ref(path->nodes[0], disk_ref, &ref))
576 goto out;
577 key.offset++;
578 btrfs_release_path(root, path);
579 ret = btrfs_insert_empty_item(trans, root, path, &key,
580 sizeof(ref));
581 }
582 if (ret)
583 goto out;
584 disk_ref = btrfs_item_ptr(path->nodes[0], path->slots[0],
585 struct btrfs_extent_ref);
586 write_extent_buffer(path->nodes[0], &ref, (unsigned long)disk_ref,
587 sizeof(ref));
588 btrfs_mark_buffer_dirty(path->nodes[0]);
589 out:
590 btrfs_release_path(root, path);
591 return ret;
592 }
593
594 int btrfs_inc_extent_ref(struct btrfs_trans_handle *trans,
595 struct btrfs_root *root,
596 u64 bytenr, u64 num_bytes,
597 u64 root_objectid, u64 ref_generation,
598 u64 owner, u64 owner_offset)
599 {
600 struct btrfs_path *path;
601 int ret;
602 struct btrfs_key key;
603 struct extent_buffer *l;
604 struct btrfs_extent_item *item;
605 u32 refs;
606
607 WARN_ON(num_bytes < root->sectorsize);
608 path = btrfs_alloc_path();
609 if (!path)
610 return -ENOMEM;
611
612 key.objectid = bytenr;
613 btrfs_set_key_type(&key, BTRFS_EXTENT_ITEM_KEY);
614 key.offset = num_bytes;
615 ret = btrfs_search_slot(trans, root->fs_info->extent_root, &key, path,
616 0, 1);
617 if (ret < 0)
618 return ret;
619 if (ret != 0) {
620 BUG();
621 }
622 BUG_ON(ret != 0);
623 l = path->nodes[0];
624 item = btrfs_item_ptr(l, path->slots[0], struct btrfs_extent_item);
625 refs = btrfs_extent_refs(l, item);
626 btrfs_set_extent_refs(l, item, refs + 1);
627 btrfs_mark_buffer_dirty(path->nodes[0]);
628
629 btrfs_release_path(root->fs_info->extent_root, path);
630
631 ret = btrfs_insert_extent_backref(trans, root->fs_info->extent_root,
632 path, bytenr, root_objectid,
633 ref_generation, owner, owner_offset);
634 BUG_ON(ret);
635 finish_current_insert(trans, root->fs_info->extent_root);
636 del_pending_extents(trans, root->fs_info->extent_root);
637
638 btrfs_free_path(path);
639 return 0;
640 }
641
642 int btrfs_extent_post_op(struct btrfs_trans_handle *trans,
643 struct btrfs_root *root)
644 {
645 finish_current_insert(trans, root->fs_info->extent_root);
646 del_pending_extents(trans, root->fs_info->extent_root);
647 return 0;
648 }
649
650 static int lookup_extent_ref(struct btrfs_trans_handle *trans,
651 struct btrfs_root *root, u64 bytenr,
652 u64 num_bytes, u32 *refs)
653 {
654 struct btrfs_path *path;
655 int ret;
656 struct btrfs_key key;
657 struct extent_buffer *l;
658 struct btrfs_extent_item *item;
659
660 WARN_ON(num_bytes < root->sectorsize);
661 path = btrfs_alloc_path();
662 key.objectid = bytenr;
663 key.offset = num_bytes;
664 btrfs_set_key_type(&key, BTRFS_EXTENT_ITEM_KEY);
665 ret = btrfs_search_slot(trans, root->fs_info->extent_root, &key, path,
666 0, 0);
667 if (ret < 0)
668 goto out;
669 if (ret != 0) {
670 btrfs_print_leaf(root, path->nodes[0]);
671 printk("failed to find block number %Lu\n", bytenr);
672 BUG();
673 }
674 l = path->nodes[0];
675 item = btrfs_item_ptr(l, path->slots[0], struct btrfs_extent_item);
676 *refs = btrfs_extent_refs(l, item);
677 out:
678 btrfs_free_path(path);
679 return 0;
680 }
681
682 int btrfs_inc_root_ref(struct btrfs_trans_handle *trans,
683 struct btrfs_root *root, u64 owner_objectid)
684 {
685 u64 generation;
686 u64 key_objectid;
687 u64 level;
688 u32 nritems;
689 struct btrfs_disk_key disk_key;
690
691 level = btrfs_header_level(root->node);
692 generation = trans->transid;
693 nritems = btrfs_header_nritems(root->node);
694 if (nritems > 0) {
695 if (level == 0)
696 btrfs_item_key(root->node, &disk_key, 0);
697 else
698 btrfs_node_key(root->node, &disk_key, 0);
699 key_objectid = btrfs_disk_key_objectid(&disk_key);
700 } else {
701 key_objectid = 0;
702 }
703 return btrfs_inc_extent_ref(trans, root, root->node->start,
704 root->node->len, owner_objectid,
705 generation, level, key_objectid);
706 }
707
708 int btrfs_inc_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root,
709 struct extent_buffer *buf)
710 {
711 u64 bytenr;
712 u32 nritems;
713 struct btrfs_key key;
714 struct btrfs_file_extent_item *fi;
715 int i;
716 int level;
717 int ret;
718 int faili;
719
720 if (!root->ref_cows)
721 return 0;
722
723 level = btrfs_header_level(buf);
724 nritems = btrfs_header_nritems(buf);
725 for (i = 0; i < nritems; i++) {
726 if (level == 0) {
727 u64 disk_bytenr;
728 btrfs_item_key_to_cpu(buf, &key, i);
729 if (btrfs_key_type(&key) != BTRFS_EXTENT_DATA_KEY)
730 continue;
731 fi = btrfs_item_ptr(buf, i,
732 struct btrfs_file_extent_item);
733 if (btrfs_file_extent_type(buf, fi) ==
734 BTRFS_FILE_EXTENT_INLINE)
735 continue;
736 disk_bytenr = btrfs_file_extent_disk_bytenr(buf, fi);
737 if (disk_bytenr == 0)
738 continue;
739 ret = btrfs_inc_extent_ref(trans, root, disk_bytenr,
740 btrfs_file_extent_disk_num_bytes(buf, fi),
741 root->root_key.objectid, trans->transid,
742 key.objectid, key.offset);
743 if (ret) {
744 faili = i;
745 goto fail;
746 }
747 } else {
748 bytenr = btrfs_node_blockptr(buf, i);
749 btrfs_node_key_to_cpu(buf, &key, i);
750 ret = btrfs_inc_extent_ref(trans, root, bytenr,
751 btrfs_level_size(root, level - 1),
752 root->root_key.objectid,
753 trans->transid,
754 level - 1, key.objectid);
755 if (ret) {
756 faili = i;
757 goto fail;
758 }
759 }
760 }
761 return 0;
762 fail:
763 WARN_ON(1);
764 #if 0
765 for (i =0; i < faili; i++) {
766 if (level == 0) {
767 u64 disk_bytenr;
768 btrfs_item_key_to_cpu(buf, &key, i);
769 if (btrfs_key_type(&key) != BTRFS_EXTENT_DATA_KEY)
770 continue;
771 fi = btrfs_item_ptr(buf, i,
772 struct btrfs_file_extent_item);
773 if (btrfs_file_extent_type(buf, fi) ==
774 BTRFS_FILE_EXTENT_INLINE)
775 continue;
776 disk_bytenr = btrfs_file_extent_disk_bytenr(buf, fi);
777 if (disk_bytenr == 0)
778 continue;
779 err = btrfs_free_extent(trans, root, disk_bytenr,
780 btrfs_file_extent_disk_num_bytes(buf,
781 fi), 0);
782 BUG_ON(err);
783 } else {
784 bytenr = btrfs_node_blockptr(buf, i);
785 err = btrfs_free_extent(trans, root, bytenr,
786 btrfs_level_size(root, level - 1), 0);
787 BUG_ON(err);
788 }
789 }
790 #endif
791 return ret;
792 }
793
794 static int write_one_cache_group(struct btrfs_trans_handle *trans,
795 struct btrfs_root *root,
796 struct btrfs_path *path,
797 struct btrfs_block_group_cache *cache)
798 {
799 int ret;
800 int pending_ret;
801 struct btrfs_root *extent_root = root->fs_info->extent_root;
802 unsigned long bi;
803 struct extent_buffer *leaf;
804
805 ret = btrfs_search_slot(trans, extent_root, &cache->key, path, 0, 1);
806 if (ret < 0)
807 goto fail;
808 BUG_ON(ret);
809
810 leaf = path->nodes[0];
811 bi = btrfs_item_ptr_offset(leaf, path->slots[0]);
812 write_extent_buffer(leaf, &cache->item, bi, sizeof(cache->item));
813 btrfs_mark_buffer_dirty(leaf);
814 btrfs_release_path(extent_root, path);
815 fail:
816 finish_current_insert(trans, extent_root);
817 pending_ret = del_pending_extents(trans, extent_root);
818 if (ret)
819 return ret;
820 if (pending_ret)
821 return pending_ret;
822 return 0;
823
824 }
825
826 int btrfs_write_dirty_block_groups(struct btrfs_trans_handle *trans,
827 struct btrfs_root *root)
828 {
829 struct extent_map_tree *block_group_cache;
830 struct btrfs_block_group_cache *cache;
831 int ret;
832 int err = 0;
833 int werr = 0;
834 struct btrfs_path *path;
835 u64 last = 0;
836 u64 start;
837 u64 end;
838 u64 ptr;
839
840 block_group_cache = &root->fs_info->block_group_cache;
841 path = btrfs_alloc_path();
842 if (!path)
843 return -ENOMEM;
844
845 while(1) {
846 ret = find_first_extent_bit(block_group_cache, last,
847 &start, &end, BLOCK_GROUP_DIRTY);
848 if (ret)
849 break;
850
851 last = end + 1;
852 ret = get_state_private(block_group_cache, start, &ptr);
853 if (ret)
854 break;
855
856 cache = (struct btrfs_block_group_cache *)(unsigned long)ptr;
857 err = write_one_cache_group(trans, root,
858 path, cache);
859 /*
860 * if we fail to write the cache group, we want
861 * to keep it marked dirty in hopes that a later
862 * write will work
863 */
864 if (err) {
865 werr = err;
866 continue;
867 }
868 clear_extent_bits(block_group_cache, start, end,
869 BLOCK_GROUP_DIRTY, GFP_NOFS);
870 }
871 btrfs_free_path(path);
872 return werr;
873 }
874
875 static int update_block_group(struct btrfs_trans_handle *trans,
876 struct btrfs_root *root,
877 u64 bytenr, u64 num_bytes, int alloc,
878 int mark_free, int data)
879 {
880 struct btrfs_block_group_cache *cache;
881 struct btrfs_fs_info *info = root->fs_info;
882 u64 total = num_bytes;
883 u64 old_val;
884 u64 byte_in_group;
885 u64 start;
886 u64 end;
887
888 while(total) {
889 cache = btrfs_lookup_block_group(info, bytenr);
890 if (!cache) {
891 return -1;
892 }
893 byte_in_group = bytenr - cache->key.objectid;
894 WARN_ON(byte_in_group > cache->key.offset);
895 start = cache->key.objectid;
896 end = start + cache->key.offset - 1;
897 set_extent_bits(&info->block_group_cache, start, end,
898 BLOCK_GROUP_DIRTY, GFP_NOFS);
899
900 old_val = btrfs_block_group_used(&cache->item);
901 num_bytes = min(total, cache->key.offset - byte_in_group);
902 if (alloc) {
903 if (cache->data != data &&
904 old_val < (cache->key.offset >> 1)) {
905 int bit_to_clear;
906 int bit_to_set;
907 cache->data = data;
908 if (data) {
909 bit_to_clear = BLOCK_GROUP_METADATA;
910 bit_to_set = BLOCK_GROUP_DATA;
911 cache->item.flags &=
912 ~BTRFS_BLOCK_GROUP_MIXED;
913 cache->item.flags |=
914 BTRFS_BLOCK_GROUP_DATA;
915 } else {
916 bit_to_clear = BLOCK_GROUP_DATA;
917 bit_to_set = BLOCK_GROUP_METADATA;
918 cache->item.flags &=
919 ~BTRFS_BLOCK_GROUP_MIXED;
920 cache->item.flags &=
921 ~BTRFS_BLOCK_GROUP_DATA;
922 }
923 clear_extent_bits(&info->block_group_cache,
924 start, end, bit_to_clear,
925 GFP_NOFS);
926 set_extent_bits(&info->block_group_cache,
927 start, end, bit_to_set,
928 GFP_NOFS);
929 } else if (cache->data != data &&
930 cache->data != BTRFS_BLOCK_GROUP_MIXED) {
931 cache->data = BTRFS_BLOCK_GROUP_MIXED;
932 set_extent_bits(&info->block_group_cache,
933 start, end,
934 BLOCK_GROUP_DATA |
935 BLOCK_GROUP_METADATA,
936 GFP_NOFS);
937 }
938 old_val += num_bytes;
939 } else {
940 old_val -= num_bytes;
941 if (mark_free) {
942 set_extent_dirty(&info->free_space_cache,
943 bytenr, bytenr + num_bytes - 1,
944 GFP_NOFS);
945 }
946 }
947 btrfs_set_block_group_used(&cache->item, old_val);
948 total -= num_bytes;
949 bytenr += num_bytes;
950 }
951 return 0;
952 }
953 static int update_pinned_extents(struct btrfs_root *root,
954 u64 bytenr, u64 num, int pin)
955 {
956 u64 len;
957 struct btrfs_block_group_cache *cache;
958 struct btrfs_fs_info *fs_info = root->fs_info;
959
960 if (pin) {
961 set_extent_dirty(&fs_info->pinned_extents,
962 bytenr, bytenr + num - 1, GFP_NOFS);
963 } else {
964 clear_extent_dirty(&fs_info->pinned_extents,
965 bytenr, bytenr + num - 1, GFP_NOFS);
966 }
967 while (num > 0) {
968 cache = btrfs_lookup_block_group(fs_info, bytenr);
969 WARN_ON(!cache);
970 len = min(num, cache->key.offset -
971 (bytenr - cache->key.objectid));
972 if (pin) {
973 cache->pinned += len;
974 fs_info->total_pinned += len;
975 } else {
976 cache->pinned -= len;
977 fs_info->total_pinned -= len;
978 }
979 bytenr += len;
980 num -= len;
981 }
982 return 0;
983 }
984
985 int btrfs_copy_pinned(struct btrfs_root *root, struct extent_map_tree *copy)
986 {
987 u64 last = 0;
988 u64 start;
989 u64 end;
990 struct extent_map_tree *pinned_extents = &root->fs_info->pinned_extents;
991 int ret;
992
993 while(1) {
994 ret = find_first_extent_bit(pinned_extents, last,
995 &start, &end, EXTENT_DIRTY);
996 if (ret)
997 break;
998 set_extent_dirty(copy, start, end, GFP_NOFS);
999 last = end + 1;
1000 }
1001 return 0;
1002 }
1003
1004 int btrfs_finish_extent_commit(struct btrfs_trans_handle *trans,
1005 struct btrfs_root *root,
1006 struct extent_map_tree *unpin)
1007 {
1008 u64 start;
1009 u64 end;
1010 int ret;
1011 struct extent_map_tree *free_space_cache;
1012 free_space_cache = &root->fs_info->free_space_cache;
1013
1014 while(1) {
1015 ret = find_first_extent_bit(unpin, 0, &start, &end,
1016 EXTENT_DIRTY);
1017 if (ret)
1018 break;
1019 update_pinned_extents(root, start, end + 1 - start, 0);
1020 clear_extent_dirty(unpin, start, end, GFP_NOFS);
1021 set_extent_dirty(free_space_cache, start, end, GFP_NOFS);
1022 }
1023 return 0;
1024 }
1025
1026 static int finish_current_insert(struct btrfs_trans_handle *trans, struct
1027 btrfs_root *extent_root)
1028 {
1029 u64 start;
1030 u64 end;
1031 struct btrfs_fs_info *info = extent_root->fs_info;
1032 struct extent_buffer *eb;
1033 struct btrfs_path *path;
1034 struct btrfs_key ins;
1035 struct btrfs_disk_key first;
1036 struct btrfs_extent_item extent_item;
1037 int ret;
1038 int level;
1039 int err = 0;
1040
1041 btrfs_set_stack_extent_refs(&extent_item, 1);
1042 btrfs_set_key_type(&ins, BTRFS_EXTENT_ITEM_KEY);
1043 path = btrfs_alloc_path();
1044
1045 while(1) {
1046 ret = find_first_extent_bit(&info->extent_ins, 0, &start,
1047 &end, EXTENT_LOCKED);
1048 if (ret)
1049 break;
1050
1051 ins.objectid = start;
1052 ins.offset = end + 1 - start;
1053 err = btrfs_insert_item(trans, extent_root, &ins,
1054 &extent_item, sizeof(extent_item));
1055 clear_extent_bits(&info->extent_ins, start, end, EXTENT_LOCKED,
1056 GFP_NOFS);
1057 eb = read_tree_block(extent_root, ins.objectid, ins.offset);
1058 level = btrfs_header_level(eb);
1059 if (level == 0) {
1060 btrfs_item_key(eb, &first, 0);
1061 } else {
1062 btrfs_node_key(eb, &first, 0);
1063 }
1064 err = btrfs_insert_extent_backref(trans, extent_root, path,
1065 start, extent_root->root_key.objectid,
1066 0, level,
1067 btrfs_disk_key_objectid(&first));
1068 BUG_ON(err);
1069 free_extent_buffer(eb);
1070 }
1071 btrfs_free_path(path);
1072 return 0;
1073 }
1074
1075 static int pin_down_bytes(struct btrfs_root *root, u64 bytenr, u32 num_bytes,
1076 int pending)
1077 {
1078 int err = 0;
1079 struct extent_buffer *buf;
1080
1081 if (!pending) {
1082 buf = btrfs_find_tree_block(root, bytenr, num_bytes);
1083 if (buf) {
1084 if (btrfs_buffer_uptodate(buf)) {
1085 u64 transid =
1086 root->fs_info->running_transaction->transid;
1087 if (btrfs_header_generation(buf) == transid) {
1088 free_extent_buffer(buf);
1089 return 1;
1090 }
1091 }
1092 free_extent_buffer(buf);
1093 }
1094 update_pinned_extents(root, bytenr, num_bytes, 1);
1095 } else {
1096 set_extent_bits(&root->fs_info->pending_del,
1097 bytenr, bytenr + num_bytes - 1,
1098 EXTENT_LOCKED, GFP_NOFS);
1099 }
1100 BUG_ON(err < 0);
1101 return 0;
1102 }
1103
1104 /*
1105 * remove an extent from the root, returns 0 on success
1106 */
1107 static int __free_extent(struct btrfs_trans_handle *trans, struct btrfs_root
1108 *root, u64 bytenr, u64 num_bytes,
1109 u64 root_objectid, u64 ref_generation,
1110 u64 owner_objectid, u64 owner_offset, int pin,
1111 int mark_free)
1112 {
1113 struct btrfs_path *path;
1114 struct btrfs_key key;
1115 struct btrfs_fs_info *info = root->fs_info;
1116 struct btrfs_root *extent_root = info->extent_root;
1117 struct extent_buffer *leaf;
1118 int ret;
1119 struct btrfs_extent_item *ei;
1120 u32 refs;
1121
1122 key.objectid = bytenr;
1123 btrfs_set_key_type(&key, BTRFS_EXTENT_ITEM_KEY);
1124 key.offset = num_bytes;
1125
1126 path = btrfs_alloc_path();
1127 if (!path)
1128 return -ENOMEM;
1129
1130 if (ref_generation && owner_objectid == 0 && root_objectid == 3) {
1131 //printk("drop backref root %Lu gen %Lu byte %Lu\n", root_objectid, ref_generation, bytenr );
1132 }
1133 ret = lookup_extent_backref(trans, extent_root, path,
1134 bytenr, root_objectid,
1135 ref_generation,
1136 owner_objectid, owner_offset, 1);
1137 if (ret == 0) {
1138 ret = btrfs_del_item(trans, extent_root, path);
1139 } else {
1140 btrfs_print_leaf(extent_root, path->nodes[0]);
1141 WARN_ON(1);
1142 printk("Unable to find ref byte nr %Lu root %Lu "
1143 " gen %Lu owner %Lu offset %Lu\n", bytenr,
1144 root_objectid, ref_generation, owner_objectid,
1145 owner_offset);
1146 }
1147 btrfs_release_path(extent_root, path);
1148 ret = btrfs_search_slot(trans, extent_root, &key, path, -1, 1);
1149 if (ret < 0)
1150 return ret;
1151 BUG_ON(ret);
1152
1153 leaf = path->nodes[0];
1154 ei = btrfs_item_ptr(leaf, path->slots[0],
1155 struct btrfs_extent_item);
1156 refs = btrfs_extent_refs(leaf, ei);
1157 BUG_ON(refs == 0);
1158 refs -= 1;
1159 btrfs_set_extent_refs(leaf, ei, refs);
1160 btrfs_mark_buffer_dirty(leaf);
1161
1162 if (refs == 0) {
1163 u64 super_used;
1164 u64 root_used;
1165
1166 if (pin) {
1167 ret = pin_down_bytes(root, bytenr, num_bytes, 0);
1168 if (ret > 0)
1169 mark_free = 1;
1170 BUG_ON(ret < 0);
1171 }
1172
1173 /* block accounting for super block */
1174 super_used = btrfs_super_bytes_used(&info->super_copy);
1175 btrfs_set_super_bytes_used(&info->super_copy,
1176 super_used - num_bytes);
1177
1178 /* block accounting for root item */
1179 root_used = btrfs_root_used(&root->root_item);
1180 btrfs_set_root_used(&root->root_item,
1181 root_used - num_bytes);
1182
1183 ret = btrfs_del_item(trans, extent_root, path);
1184 if (ret) {
1185 return ret;
1186 }
1187 ret = update_block_group(trans, root, bytenr, num_bytes, 0,
1188 mark_free, 0);
1189 BUG_ON(ret);
1190 }
1191 btrfs_free_path(path);
1192 finish_current_insert(trans, extent_root);
1193 return ret;
1194 }
1195
1196 /*
1197 * find all the blocks marked as pending in the radix tree and remove
1198 * them from the extent map
1199 */
1200 static int del_pending_extents(struct btrfs_trans_handle *trans, struct
1201 btrfs_root *extent_root)
1202 {
1203 int ret;
1204 int err = 0;
1205 u64 start;
1206 u64 end;
1207 struct extent_map_tree *pending_del;
1208 struct extent_map_tree *pinned_extents;
1209
1210 pending_del = &extent_root->fs_info->pending_del;
1211 pinned_extents = &extent_root->fs_info->pinned_extents;
1212
1213 while(1) {
1214 ret = find_first_extent_bit(pending_del, 0, &start, &end,
1215 EXTENT_LOCKED);
1216 if (ret)
1217 break;
1218 update_pinned_extents(extent_root, start, end + 1 - start, 1);
1219 clear_extent_bits(pending_del, start, end, EXTENT_LOCKED,
1220 GFP_NOFS);
1221 ret = __free_extent(trans, extent_root,
1222 start, end + 1 - start,
1223 extent_root->root_key.objectid,
1224 0, 0, 0, 0, 0);
1225 if (ret)
1226 err = ret;
1227 }
1228 return err;
1229 }
1230
1231 /*
1232 * remove an extent from the root, returns 0 on success
1233 */
1234 int btrfs_free_extent(struct btrfs_trans_handle *trans, struct btrfs_root
1235 *root, u64 bytenr, u64 num_bytes,
1236 u64 root_objectid, u64 ref_generation,
1237 u64 owner_objectid, u64 owner_offset, int pin)
1238 {
1239 struct btrfs_root *extent_root = root->fs_info->extent_root;
1240 int pending_ret;
1241 int ret;
1242
1243 WARN_ON(num_bytes < root->sectorsize);
1244 if (!root->ref_cows)
1245 ref_generation = 0;
1246
1247 if (root == extent_root) {
1248 pin_down_bytes(root, bytenr, num_bytes, 1);
1249 return 0;
1250 }
1251 ret = __free_extent(trans, root, bytenr, num_bytes, root_objectid,
1252 ref_generation, owner_objectid, owner_offset,
1253 pin, pin == 0);
1254 pending_ret = del_pending_extents(trans, root->fs_info->extent_root);
1255 return ret ? ret : pending_ret;
1256 }
1257
1258 static u64 stripe_align(struct btrfs_root *root, u64 val)
1259 {
1260 u64 mask = ((u64)root->stripesize - 1);
1261 u64 ret = (val + mask) & ~mask;
1262 return ret;
1263 }
1264
1265 /*
1266 * walks the btree of allocated extents and find a hole of a given size.
1267 * The key ins is changed to record the hole:
1268 * ins->objectid == block start
1269 * ins->flags = BTRFS_EXTENT_ITEM_KEY
1270 * ins->offset == number of blocks
1271 * Any available blocks before search_start are skipped.
1272 */
1273 static int find_free_extent(struct btrfs_trans_handle *trans, struct btrfs_root
1274 *orig_root, u64 num_bytes, u64 empty_size,
1275 u64 search_start, u64 search_end, u64 hint_byte,
1276 struct btrfs_key *ins, u64 exclude_start,
1277 u64 exclude_nr, int data)
1278 {
1279 struct btrfs_path *path;
1280 struct btrfs_key key;
1281 u64 hole_size = 0;
1282 u64 aligned;
1283 int ret;
1284 int slot = 0;
1285 u64 last_byte = 0;
1286 u64 orig_search_start = search_start;
1287 int start_found;
1288 struct extent_buffer *l;
1289 struct btrfs_root * root = orig_root->fs_info->extent_root;
1290 struct btrfs_fs_info *info = root->fs_info;
1291 u64 total_needed = num_bytes;
1292 int level;
1293 struct btrfs_block_group_cache *block_group;
1294 int full_scan = 0;
1295 int wrapped = 0;
1296 u64 cached_start;
1297
1298 WARN_ON(num_bytes < root->sectorsize);
1299 btrfs_set_key_type(ins, BTRFS_EXTENT_ITEM_KEY);
1300
1301 level = btrfs_header_level(root->node);
1302
1303 if (num_bytes >= 32 * 1024 * 1024 && hint_byte) {
1304 data = BTRFS_BLOCK_GROUP_MIXED;
1305 }
1306
1307 if (search_end == (u64)-1)
1308 search_end = btrfs_super_total_bytes(&info->super_copy);
1309 if (hint_byte) {
1310 block_group = btrfs_lookup_block_group(info, hint_byte);
1311 if (!block_group)
1312 hint_byte = search_start;
1313 block_group = btrfs_find_block_group(root, block_group,
1314 hint_byte, data, 1);
1315 } else {
1316 block_group = btrfs_find_block_group(root,
1317 trans->block_group,
1318 search_start, data, 1);
1319 }
1320
1321 total_needed += empty_size;
1322 path = btrfs_alloc_path();
1323 check_failed:
1324 if (!block_group) {
1325 block_group = btrfs_lookup_block_group(info, search_start);
1326 if (!block_group)
1327 block_group = btrfs_lookup_block_group(info,
1328 orig_search_start);
1329 }
1330 search_start = find_search_start(root, &block_group, search_start,
1331 total_needed, data, full_scan);
1332 search_start = stripe_align(root, search_start);
1333 cached_start = search_start;
1334 btrfs_init_path(path);
1335 ins->objectid = search_start;
1336 ins->offset = 0;
1337 start_found = 0;
1338 path->reada = 2;
1339
1340 ret = btrfs_search_slot(trans, root, ins, path, 0, 0);
1341 if (ret < 0)
1342 goto error;
1343
1344 if (path->slots[0] > 0) {
1345 path->slots[0]--;
1346 }
1347
1348 l = path->nodes[0];
1349 btrfs_item_key_to_cpu(l, &key, path->slots[0]);
1350
1351 /*
1352 * walk backwards to find the first extent item key
1353 */
1354 while(btrfs_key_type(&key) != BTRFS_EXTENT_ITEM_KEY) {
1355 if (path->slots[0] == 0) {
1356 ret = btrfs_prev_leaf(root, path);
1357 if (ret != 0) {
1358 ret = btrfs_search_slot(trans, root, ins,
1359 path, 0, 0);
1360 if (ret < 0)
1361 goto error;
1362 if (path->slots[0] > 0)
1363 path->slots[0]--;
1364 break;
1365 }
1366 } else {
1367 path->slots[0]--;
1368 }
1369 l = path->nodes[0];
1370 btrfs_item_key_to_cpu(l, &key, path->slots[0]);
1371 }
1372 while (1) {
1373 l = path->nodes[0];
1374 slot = path->slots[0];
1375 if (slot >= btrfs_header_nritems(l)) {
1376 ret = btrfs_next_leaf(root, path);
1377 if (ret == 0)
1378 continue;
1379 if (ret < 0)
1380 goto error;
1381
1382 search_start = max(search_start,
1383 block_group->key.objectid);
1384 if (!start_found) {
1385 aligned = stripe_align(root, search_start);
1386 ins->objectid = aligned;
1387 if (aligned >= search_end) {
1388 ret = -ENOSPC;
1389 goto error;
1390 }
1391 ins->offset = search_end - aligned;
1392 start_found = 1;
1393 goto check_pending;
1394 }
1395 ins->objectid = stripe_align(root,
1396 last_byte > search_start ?
1397 last_byte : search_start);
1398 if (search_end <= ins->objectid) {
1399 ret = -ENOSPC;
1400 goto error;
1401 }
1402 ins->offset = search_end - ins->objectid;
1403 BUG_ON(ins->objectid >= search_end);
1404 goto check_pending;
1405 }
1406 btrfs_item_key_to_cpu(l, &key, slot);
1407
1408 if (key.objectid >= search_start && key.objectid > last_byte &&
1409 start_found) {
1410 if (last_byte < search_start)
1411 last_byte = search_start;
1412 aligned = stripe_align(root, last_byte);
1413 hole_size = key.objectid - aligned;
1414 if (key.objectid > aligned && hole_size >= num_bytes) {
1415 ins->objectid = aligned;
1416 ins->offset = hole_size;
1417 goto check_pending;
1418 }
1419 }
1420 if (btrfs_key_type(&key) != BTRFS_EXTENT_ITEM_KEY) {
1421 if (!start_found && btrfs_key_type(&key) ==
1422 BTRFS_BLOCK_GROUP_ITEM_KEY) {
1423 last_byte = key.objectid;
1424 start_found = 1;
1425 }
1426 goto next;
1427 }
1428
1429
1430 start_found = 1;
1431 last_byte = key.objectid + key.offset;
1432
1433 if (!full_scan && data != BTRFS_BLOCK_GROUP_MIXED &&
1434 last_byte >= block_group->key.objectid +
1435 block_group->key.offset) {
1436 btrfs_release_path(root, path);
1437 search_start = block_group->key.objectid +
1438 block_group->key.offset;
1439 goto new_group;
1440 }
1441 next:
1442 path->slots[0]++;
1443 cond_resched();
1444 }
1445 check_pending:
1446 /* we have to make sure we didn't find an extent that has already
1447 * been allocated by the map tree or the original allocation
1448 */
1449 btrfs_release_path(root, path);
1450 BUG_ON(ins->objectid < search_start);
1451
1452 if (ins->objectid + num_bytes >= search_end)
1453 goto enospc;
1454 if (!full_scan && data != BTRFS_BLOCK_GROUP_MIXED &&
1455 ins->objectid + num_bytes > block_group->
1456 key.objectid + block_group->key.offset) {
1457 search_start = block_group->key.objectid +
1458 block_group->key.offset;
1459 goto new_group;
1460 }
1461 if (test_range_bit(&info->extent_ins, ins->objectid,
1462 ins->objectid + num_bytes -1, EXTENT_LOCKED, 0)) {
1463 search_start = ins->objectid + num_bytes;
1464 goto new_group;
1465 }
1466 if (test_range_bit(&info->pinned_extents, ins->objectid,
1467 ins->objectid + num_bytes -1, EXTENT_DIRTY, 0)) {
1468 search_start = ins->objectid + num_bytes;
1469 goto new_group;
1470 }
1471 if (exclude_nr > 0 && (ins->objectid + num_bytes > exclude_start &&
1472 ins->objectid < exclude_start + exclude_nr)) {
1473 search_start = exclude_start + exclude_nr;
1474 goto new_group;
1475 }
1476 if (!data) {
1477 block_group = btrfs_lookup_block_group(info, ins->objectid);
1478 if (block_group)
1479 trans->block_group = block_group;
1480 }
1481 ins->offset = num_bytes;
1482 btrfs_free_path(path);
1483 return 0;
1484
1485 new_group:
1486 if (search_start + num_bytes >= search_end) {
1487 enospc:
1488 search_start = orig_search_start;
1489 if (full_scan) {
1490 ret = -ENOSPC;
1491 goto error;
1492 }
1493 if (wrapped) {
1494 if (!full_scan)
1495 total_needed -= empty_size;
1496 full_scan = 1;
1497 data = BTRFS_BLOCK_GROUP_MIXED;
1498 } else
1499 wrapped = 1;
1500 }
1501 block_group = btrfs_lookup_block_group(info, search_start);
1502 cond_resched();
1503 block_group = btrfs_find_block_group(root, block_group,
1504 search_start, data, 0);
1505 goto check_failed;
1506
1507 error:
1508 btrfs_release_path(root, path);
1509 btrfs_free_path(path);
1510 return ret;
1511 }
1512 /*
1513 * finds a free extent and does all the dirty work required for allocation
1514 * returns the key for the extent through ins, and a tree buffer for
1515 * the first block of the extent through buf.
1516 *
1517 * returns 0 if everything worked, non-zero otherwise.
1518 */
1519 int btrfs_alloc_extent(struct btrfs_trans_handle *trans,
1520 struct btrfs_root *root,
1521 u64 num_bytes, u64 root_objectid, u64 ref_generation,
1522 u64 owner, u64 owner_offset,
1523 u64 empty_size, u64 hint_byte,
1524 u64 search_end, struct btrfs_key *ins, int data)
1525 {
1526 int ret;
1527 int pending_ret;
1528 u64 super_used, root_used;
1529 u64 search_start = 0;
1530 struct btrfs_fs_info *info = root->fs_info;
1531 struct btrfs_root *extent_root = info->extent_root;
1532 struct btrfs_extent_item extent_item;
1533 struct btrfs_path *path;
1534
1535 btrfs_set_stack_extent_refs(&extent_item, 1);
1536
1537 WARN_ON(num_bytes < root->sectorsize);
1538 ret = find_free_extent(trans, root, num_bytes, empty_size,
1539 search_start, search_end, hint_byte, ins,
1540 trans->alloc_exclude_start,
1541 trans->alloc_exclude_nr, data);
1542 BUG_ON(ret);
1543 if (ret)
1544 return ret;
1545
1546 /* block accounting for super block */
1547 super_used = btrfs_super_bytes_used(&info->super_copy);
1548 btrfs_set_super_bytes_used(&info->super_copy, super_used + num_bytes);
1549
1550 /* block accounting for root item */
1551 root_used = btrfs_root_used(&root->root_item);
1552 btrfs_set_root_used(&root->root_item, root_used + num_bytes);
1553
1554 clear_extent_dirty(&root->fs_info->free_space_cache,
1555 ins->objectid, ins->objectid + ins->offset - 1,
1556 GFP_NOFS);
1557
1558 if (root == extent_root) {
1559 set_extent_bits(&root->fs_info->extent_ins, ins->objectid,
1560 ins->objectid + ins->offset - 1,
1561 EXTENT_LOCKED, GFP_NOFS);
1562 WARN_ON(data == 1);
1563 goto update_block;
1564 }
1565
1566 WARN_ON(trans->alloc_exclude_nr);
1567 trans->alloc_exclude_start = ins->objectid;
1568 trans->alloc_exclude_nr = ins->offset;
1569 ret = btrfs_insert_item(trans, extent_root, ins, &extent_item,
1570 sizeof(extent_item));
1571
1572 trans->alloc_exclude_start = 0;
1573 trans->alloc_exclude_nr = 0;
1574 BUG_ON(ret);
1575
1576 path = btrfs_alloc_path();
1577 BUG_ON(!path);
1578 ret = btrfs_insert_extent_backref(trans, extent_root, path,
1579 ins->objectid, root_objectid,
1580 ref_generation, owner, owner_offset);
1581
1582 BUG_ON(ret);
1583 btrfs_free_path(path);
1584 finish_current_insert(trans, extent_root);
1585 pending_ret = del_pending_extents(trans, extent_root);
1586
1587 if (ret) {
1588 return ret;
1589 }
1590 if (pending_ret) {
1591 return pending_ret;
1592 }
1593
1594 update_block:
1595 ret = update_block_group(trans, root, ins->objectid, ins->offset, 1, 0,
1596 data);
1597 BUG_ON(ret);
1598 return 0;
1599 }
1600
1601 /*
1602 * helper function to allocate a block for a given tree
1603 * returns the tree buffer or NULL.
1604 */
1605 struct extent_buffer *btrfs_alloc_free_block(struct btrfs_trans_handle *trans,
1606 struct btrfs_root *root,
1607 u32 blocksize,
1608 u64 root_objectid, u64 hint,
1609 u64 empty_size)
1610 {
1611 u64 ref_generation;
1612
1613 if (root->ref_cows)
1614 ref_generation = trans->transid;
1615 else
1616 ref_generation = 0;
1617
1618
1619 return __btrfs_alloc_free_block(trans, root, blocksize, root_objectid,
1620 ref_generation, 0, 0, hint, empty_size);
1621 }
1622
1623 /*
1624 * helper function to allocate a block for a given tree
1625 * returns the tree buffer or NULL.
1626 */
1627 struct extent_buffer *__btrfs_alloc_free_block(struct btrfs_trans_handle *trans,
1628 struct btrfs_root *root,
1629 u32 blocksize,
1630 u64 root_objectid,
1631 u64 ref_generation,
1632 u64 first_objectid,
1633 int level,
1634 u64 hint,
1635 u64 empty_size)
1636 {
1637 struct btrfs_key ins;
1638 int ret;
1639 struct extent_buffer *buf;
1640
1641 ret = btrfs_alloc_extent(trans, root, blocksize,
1642 root_objectid, ref_generation,
1643 level, first_objectid, empty_size, hint,
1644 (u64)-1, &ins, 0);
1645 if (ret) {
1646 BUG_ON(ret > 0);
1647 return ERR_PTR(ret);
1648 }
1649 buf = btrfs_find_create_tree_block(root, ins.objectid, blocksize);
1650 if (!buf) {
1651 btrfs_free_extent(trans, root, ins.objectid, blocksize,
1652 root->root_key.objectid, ref_generation,
1653 0, 0, 0);
1654 return ERR_PTR(-ENOMEM);
1655 }
1656 btrfs_set_buffer_uptodate(buf);
1657 set_extent_dirty(&trans->transaction->dirty_pages, buf->start,
1658 buf->start + buf->len - 1, GFP_NOFS);
1659 set_extent_bits(&BTRFS_I(root->fs_info->btree_inode)->extent_tree,
1660 buf->start, buf->start + buf->len - 1,
1661 EXTENT_CSUM, GFP_NOFS);
1662 buf->flags |= EXTENT_CSUM;
1663 btrfs_set_buffer_defrag(buf);
1664 trans->blocks_used++;
1665 return buf;
1666 }
1667
1668 static int drop_leaf_ref(struct btrfs_trans_handle *trans,
1669 struct btrfs_root *root, struct extent_buffer *leaf)
1670 {
1671 u64 leaf_owner;
1672 u64 leaf_generation;
1673 struct btrfs_key key;
1674 struct btrfs_file_extent_item *fi;
1675 int i;
1676 int nritems;
1677 int ret;
1678
1679 BUG_ON(!btrfs_is_leaf(leaf));
1680 nritems = btrfs_header_nritems(leaf);
1681 leaf_owner = btrfs_header_owner(leaf);
1682 leaf_generation = btrfs_header_generation(leaf);
1683
1684 for (i = 0; i < nritems; i++) {
1685 u64 disk_bytenr;
1686
1687 btrfs_item_key_to_cpu(leaf, &key, i);
1688 if (btrfs_key_type(&key) != BTRFS_EXTENT_DATA_KEY)
1689 continue;
1690 fi = btrfs_item_ptr(leaf, i, struct btrfs_file_extent_item);
1691 if (btrfs_file_extent_type(leaf, fi) ==
1692 BTRFS_FILE_EXTENT_INLINE)
1693 continue;
1694 /*
1695 * FIXME make sure to insert a trans record that
1696 * repeats the snapshot del on crash
1697 */
1698 disk_bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
1699 if (disk_bytenr == 0)
1700 continue;
1701 ret = btrfs_free_extent(trans, root, disk_bytenr,
1702 btrfs_file_extent_disk_num_bytes(leaf, fi),
1703 leaf_owner, leaf_generation,
1704 key.objectid, key.offset, 0);
1705 BUG_ON(ret);
1706 }
1707 return 0;
1708 }
1709
1710 static void reada_walk_down(struct btrfs_root *root,
1711 struct extent_buffer *node)
1712 {
1713 int i;
1714 u32 nritems;
1715 u64 bytenr;
1716 int ret;
1717 u32 refs;
1718 int level;
1719 u32 blocksize;
1720
1721 nritems = btrfs_header_nritems(node);
1722 level = btrfs_header_level(node);
1723 for (i = 0; i < nritems; i++) {
1724 bytenr = btrfs_node_blockptr(node, i);
1725 blocksize = btrfs_level_size(root, level - 1);
1726 ret = lookup_extent_ref(NULL, root, bytenr, blocksize, &refs);
1727 BUG_ON(ret);
1728 if (refs != 1)
1729 continue;
1730 mutex_unlock(&root->fs_info->fs_mutex);
1731 ret = readahead_tree_block(root, bytenr, blocksize);
1732 cond_resched();
1733 mutex_lock(&root->fs_info->fs_mutex);
1734 if (ret)
1735 break;
1736 }
1737 }
1738
1739 /*
1740 * helper function for drop_snapshot, this walks down the tree dropping ref
1741 * counts as it goes.
1742 */
1743 static int walk_down_tree(struct btrfs_trans_handle *trans, struct btrfs_root
1744 *root, struct btrfs_path *path, int *level)
1745 {
1746 u64 root_owner;
1747 u64 root_gen;
1748 u64 bytenr;
1749 struct extent_buffer *next;
1750 struct extent_buffer *cur;
1751 struct extent_buffer *parent;
1752 u32 blocksize;
1753 int ret;
1754 u32 refs;
1755
1756 WARN_ON(*level < 0);
1757 WARN_ON(*level >= BTRFS_MAX_LEVEL);
1758 ret = lookup_extent_ref(trans, root,
1759 path->nodes[*level]->start,
1760 path->nodes[*level]->len, &refs);
1761 BUG_ON(ret);
1762 if (refs > 1)
1763 goto out;
1764
1765 /*
1766 * walk down to the last node level and free all the leaves
1767 */
1768 while(*level >= 0) {
1769 WARN_ON(*level < 0);
1770 WARN_ON(*level >= BTRFS_MAX_LEVEL);
1771 cur = path->nodes[*level];
1772
1773 if (*level > 0 && path->slots[*level] == 0)
1774 reada_walk_down(root, cur);
1775
1776 if (btrfs_header_level(cur) != *level)
1777 WARN_ON(1);
1778
1779 if (path->slots[*level] >=
1780 btrfs_header_nritems(cur))
1781 break;
1782 if (*level == 0) {
1783 ret = drop_leaf_ref(trans, root, cur);
1784 BUG_ON(ret);
1785 break;
1786 }
1787 bytenr = btrfs_node_blockptr(cur, path->slots[*level]);
1788 blocksize = btrfs_level_size(root, *level - 1);
1789 ret = lookup_extent_ref(trans, root, bytenr, blocksize, &refs);
1790 BUG_ON(ret);
1791 if (refs != 1) {
1792 parent = path->nodes[*level];
1793 root_owner = btrfs_header_owner(parent);
1794 root_gen = btrfs_header_generation(parent);
1795 path->slots[*level]++;
1796 ret = btrfs_free_extent(trans, root, bytenr,
1797 blocksize, root_owner,
1798 root_gen, 0, 0, 1);
1799 BUG_ON(ret);
1800 continue;
1801 }
1802 next = btrfs_find_tree_block(root, bytenr, blocksize);
1803 if (!next || !btrfs_buffer_uptodate(next)) {
1804 free_extent_buffer(next);
1805 mutex_unlock(&root->fs_info->fs_mutex);
1806 next = read_tree_block(root, bytenr, blocksize);
1807 mutex_lock(&root->fs_info->fs_mutex);
1808
1809 /* we dropped the lock, check one more time */
1810 ret = lookup_extent_ref(trans, root, bytenr,
1811 blocksize, &refs);
1812 BUG_ON(ret);
1813 if (refs != 1) {
1814 parent = path->nodes[*level];
1815 root_owner = btrfs_header_owner(parent);
1816 root_gen = btrfs_header_generation(parent);
1817
1818 path->slots[*level]++;
1819 free_extent_buffer(next);
1820 ret = btrfs_free_extent(trans, root, bytenr,
1821 blocksize,
1822 root_owner,
1823 root_gen, 0, 0, 1);
1824 BUG_ON(ret);
1825 continue;
1826 }
1827 }
1828 WARN_ON(*level <= 0);
1829 if (path->nodes[*level-1])
1830 free_extent_buffer(path->nodes[*level-1]);
1831 path->nodes[*level-1] = next;
1832 *level = btrfs_header_level(next);
1833 path->slots[*level] = 0;
1834 }
1835 out:
1836 WARN_ON(*level < 0);
1837 WARN_ON(*level >= BTRFS_MAX_LEVEL);
1838
1839 if (path->nodes[*level] == root->node) {
1840 root_owner = root->root_key.objectid;
1841 parent = path->nodes[*level];
1842 } else {
1843 parent = path->nodes[*level + 1];
1844 root_owner = btrfs_header_owner(parent);
1845 }
1846
1847 root_gen = btrfs_header_generation(parent);
1848 ret = btrfs_free_extent(trans, root, path->nodes[*level]->start,
1849 path->nodes[*level]->len,
1850 root_owner, root_gen, 0, 0, 1);
1851 free_extent_buffer(path->nodes[*level]);
1852 path->nodes[*level] = NULL;
1853 *level += 1;
1854 BUG_ON(ret);
1855 return 0;
1856 }
1857
1858 /*
1859 * helper for dropping snapshots. This walks back up the tree in the path
1860 * to find the first node higher up where we haven't yet gone through
1861 * all the slots
1862 */
1863 static int walk_up_tree(struct btrfs_trans_handle *trans, struct btrfs_root
1864 *root, struct btrfs_path *path, int *level)
1865 {
1866 u64 root_owner;
1867 u64 root_gen;
1868 struct btrfs_root_item *root_item = &root->root_item;
1869 int i;
1870 int slot;
1871 int ret;
1872
1873 for(i = *level; i < BTRFS_MAX_LEVEL - 1 && path->nodes[i]; i++) {
1874 slot = path->slots[i];
1875 if (slot < btrfs_header_nritems(path->nodes[i]) - 1) {
1876 struct extent_buffer *node;
1877 struct btrfs_disk_key disk_key;
1878 node = path->nodes[i];
1879 path->slots[i]++;
1880 *level = i;
1881 WARN_ON(*level == 0);
1882 btrfs_node_key(node, &disk_key, path->slots[i]);
1883 memcpy(&root_item->drop_progress,
1884 &disk_key, sizeof(disk_key));
1885 root_item->drop_level = i;
1886 return 0;
1887 } else {
1888 if (path->nodes[*level] == root->node) {
1889 root_owner = root->root_key.objectid;
1890 root_gen =
1891 btrfs_header_generation(path->nodes[*level]);
1892 } else {
1893 struct extent_buffer *node;
1894 node = path->nodes[*level + 1];
1895 root_owner = btrfs_header_owner(node);
1896 root_gen = btrfs_header_generation(node);
1897 }
1898 ret = btrfs_free_extent(trans, root,
1899 path->nodes[*level]->start,
1900 path->nodes[*level]->len,
1901 root_owner, root_gen, 0, 0, 1);
1902 BUG_ON(ret);
1903 free_extent_buffer(path->nodes[*level]);
1904 path->nodes[*level] = NULL;
1905 *level = i + 1;
1906 }
1907 }
1908 return 1;
1909 }
1910
1911 /*
1912 * drop the reference count on the tree rooted at 'snap'. This traverses
1913 * the tree freeing any blocks that have a ref count of zero after being
1914 * decremented.
1915 */
1916 int btrfs_drop_snapshot(struct btrfs_trans_handle *trans, struct btrfs_root
1917 *root)
1918 {
1919 int ret = 0;
1920 int wret;
1921 int level;
1922 struct btrfs_path *path;
1923 int i;
1924 int orig_level;
1925 struct btrfs_root_item *root_item = &root->root_item;
1926
1927 path = btrfs_alloc_path();
1928 BUG_ON(!path);
1929
1930 level = btrfs_header_level(root->node);
1931 orig_level = level;
1932 if (btrfs_disk_key_objectid(&root_item->drop_progress) == 0) {
1933 path->nodes[level] = root->node;
1934 extent_buffer_get(root->node);
1935 path->slots[level] = 0;
1936 } else {
1937 struct btrfs_key key;
1938 struct btrfs_disk_key found_key;
1939 struct extent_buffer *node;
1940
1941 btrfs_disk_key_to_cpu(&key, &root_item->drop_progress);
1942 level = root_item->drop_level;
1943 path->lowest_level = level;
1944 wret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
1945 if (wret < 0) {
1946 ret = wret;
1947 goto out;
1948 }
1949 node = path->nodes[level];
1950 btrfs_node_key(node, &found_key, path->slots[level]);
1951 WARN_ON(memcmp(&found_key, &root_item->drop_progress,
1952 sizeof(found_key)));
1953 }
1954 while(1) {
1955 wret = walk_down_tree(trans, root, path, &level);
1956 if (wret > 0)
1957 break;
1958 if (wret < 0)
1959 ret = wret;
1960
1961 wret = walk_up_tree(trans, root, path, &level);
1962 if (wret > 0)
1963 break;
1964 if (wret < 0)
1965 ret = wret;
1966 ret = -EAGAIN;
1967 break;
1968 }
1969 for (i = 0; i <= orig_level; i++) {
1970 if (path->nodes[i]) {
1971 free_extent_buffer(path->nodes[i]);
1972 path->nodes[i] = NULL;
1973 }
1974 }
1975 out:
1976 btrfs_free_path(path);
1977 return ret;
1978 }
1979
1980 int btrfs_free_block_groups(struct btrfs_fs_info *info)
1981 {
1982 u64 start;
1983 u64 end;
1984 u64 ptr;
1985 int ret;
1986 while(1) {
1987 ret = find_first_extent_bit(&info->block_group_cache, 0,
1988 &start, &end, (unsigned int)-1);
1989 if (ret)
1990 break;
1991 ret = get_state_private(&info->block_group_cache, start, &ptr);
1992 if (!ret)
1993 kfree((void *)(unsigned long)ptr);
1994 clear_extent_bits(&info->block_group_cache, start,
1995 end, (unsigned int)-1, GFP_NOFS);
1996 }
1997 while(1) {
1998 ret = find_first_extent_bit(&info->free_space_cache, 0,
1999 &start, &end, EXTENT_DIRTY);
2000 if (ret)
2001 break;
2002 clear_extent_dirty(&info->free_space_cache, start,
2003 end, GFP_NOFS);
2004 }
2005 return 0;
2006 }
2007
2008 int btrfs_read_block_groups(struct btrfs_root *root)
2009 {
2010 struct btrfs_path *path;
2011 int ret;
2012 int err = 0;
2013 int bit;
2014 struct btrfs_block_group_cache *cache;
2015 struct btrfs_fs_info *info = root->fs_info;
2016 struct extent_map_tree *block_group_cache;
2017 struct btrfs_key key;
2018 struct btrfs_key found_key;
2019 struct extent_buffer *leaf;
2020
2021 block_group_cache = &info->block_group_cache;
2022
2023 root = info->extent_root;
2024 key.objectid = 0;
2025 key.offset = BTRFS_BLOCK_GROUP_SIZE;
2026 btrfs_set_key_type(&key, BTRFS_BLOCK_GROUP_ITEM_KEY);
2027
2028 path = btrfs_alloc_path();
2029 if (!path)
2030 return -ENOMEM;
2031
2032 while(1) {
2033 ret = btrfs_search_slot(NULL, info->extent_root,
2034 &key, path, 0, 0);
2035 if (ret != 0) {
2036 err = ret;
2037 break;
2038 }
2039 leaf = path->nodes[0];
2040 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
2041 cache = kmalloc(sizeof(*cache), GFP_NOFS);
2042 if (!cache) {
2043 err = -1;
2044 break;
2045 }
2046
2047 read_extent_buffer(leaf, &cache->item,
2048 btrfs_item_ptr_offset(leaf, path->slots[0]),
2049 sizeof(cache->item));
2050 memcpy(&cache->key, &found_key, sizeof(found_key));
2051 cache->cached = 0;
2052 cache->pinned = 0;
2053 key.objectid = found_key.objectid + found_key.offset;
2054 btrfs_release_path(root, path);
2055
2056 if (cache->item.flags & BTRFS_BLOCK_GROUP_MIXED) {
2057 bit = BLOCK_GROUP_DATA | BLOCK_GROUP_METADATA;
2058 cache->data = BTRFS_BLOCK_GROUP_MIXED;
2059 } else if (cache->item.flags & BTRFS_BLOCK_GROUP_DATA) {
2060 bit = BLOCK_GROUP_DATA;
2061 cache->data = BTRFS_BLOCK_GROUP_DATA;
2062 } else {
2063 bit = BLOCK_GROUP_METADATA;
2064 cache->data = 0;
2065 }
2066
2067 /* use EXTENT_LOCKED to prevent merging */
2068 set_extent_bits(block_group_cache, found_key.objectid,
2069 found_key.objectid + found_key.offset - 1,
2070 bit | EXTENT_LOCKED, GFP_NOFS);
2071 set_state_private(block_group_cache, found_key.objectid,
2072 (unsigned long)cache);
2073
2074 if (key.objectid >=
2075 btrfs_super_total_bytes(&info->super_copy))
2076 break;
2077 }
2078
2079 btrfs_free_path(path);
2080 return 0;
2081 }
Linux kernel - Deliverables
This page took 0.071752 seconds and 6 git commands to generate.