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count_snapshots: Properly update the leaf pointer after btrfs_next_leaf
[mirror_ubuntu-hirsute-kernel.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 <linux/pagemap.h>
22 #include "hash.h"
23 #include "ctree.h"
24 #include "disk-io.h"
25 #include "print-tree.h"
26 #include "transaction.h"
27
28 #define BLOCK_GROUP_DATA EXTENT_WRITEBACK
29 #define BLOCK_GROUP_METADATA EXTENT_UPTODATE
30 #define BLOCK_GROUP_DIRTY EXTENT_DIRTY
31
32 static int finish_current_insert(struct btrfs_trans_handle *trans, struct
33 btrfs_root *extent_root);
34 static int del_pending_extents(struct btrfs_trans_handle *trans, struct
35 btrfs_root *extent_root);
36
37 static int cache_block_group(struct btrfs_root *root,
38 struct btrfs_block_group_cache *block_group)
39 {
40 struct btrfs_path *path;
41 int ret;
42 struct btrfs_key key;
43 struct extent_buffer *leaf;
44 struct extent_map_tree *free_space_cache;
45 int slot;
46 u64 last = 0;
47 u64 hole_size;
48 u64 first_free;
49 int found = 0;
50
51 if (!block_group)
52 return 0;
53
54 root = root->fs_info->extent_root;
55 free_space_cache = &root->fs_info->free_space_cache;
56
57 if (block_group->cached)
58 return 0;
59
60 path = btrfs_alloc_path();
61 if (!path)
62 return -ENOMEM;
63
64 path->reada = 2;
65 first_free = block_group->key.objectid;
66 key.objectid = block_group->key.objectid;
67 key.offset = 0;
68
69 btrfs_set_key_type(&key, BTRFS_EXTENT_ITEM_KEY);
70 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
71
72 if (ret < 0)
73 return ret;
74
75 if (ret && path->slots[0] > 0)
76 path->slots[0]--;
77
78 while(1) {
79 leaf = path->nodes[0];
80 slot = path->slots[0];
81 if (slot >= btrfs_header_nritems(leaf)) {
82 ret = btrfs_next_leaf(root, path);
83 if (ret < 0)
84 goto err;
85 if (ret == 0) {
86 continue;
87 } else {
88 break;
89 }
90 }
91
92 btrfs_item_key_to_cpu(leaf, &key, slot);
93 if (key.objectid < block_group->key.objectid) {
94 if (btrfs_key_type(&key) != BTRFS_EXTENT_REF_KEY &&
95 key.objectid + key.offset > first_free)
96 first_free = key.objectid + key.offset;
97 goto next;
98 }
99
100 if (key.objectid >= block_group->key.objectid +
101 block_group->key.offset) {
102 break;
103 }
104
105 if (btrfs_key_type(&key) == BTRFS_EXTENT_ITEM_KEY) {
106 if (!found) {
107 last = first_free;
108 found = 1;
109 }
110 if (key.objectid > last) {
111 hole_size = key.objectid - last;
112 set_extent_dirty(free_space_cache, last,
113 last + hole_size - 1,
114 GFP_NOFS);
115 }
116 last = key.objectid + key.offset;
117 }
118 next:
119 path->slots[0]++;
120 }
121
122 if (!found)
123 last = first_free;
124 if (block_group->key.objectid +
125 block_group->key.offset > last) {
126 hole_size = block_group->key.objectid +
127 block_group->key.offset - last;
128 set_extent_dirty(free_space_cache, last,
129 last + hole_size - 1, GFP_NOFS);
130 }
131 block_group->cached = 1;
132 err:
133 btrfs_free_path(path);
134 return 0;
135 }
136
137 struct btrfs_block_group_cache *btrfs_lookup_block_group(struct
138 btrfs_fs_info *info,
139 u64 bytenr)
140 {
141 struct extent_map_tree *block_group_cache;
142 struct btrfs_block_group_cache *block_group = NULL;
143 u64 ptr;
144 u64 start;
145 u64 end;
146 int ret;
147
148 block_group_cache = &info->block_group_cache;
149 ret = find_first_extent_bit(block_group_cache,
150 bytenr, &start, &end,
151 BLOCK_GROUP_DATA | BLOCK_GROUP_METADATA);
152 if (ret) {
153 return NULL;
154 }
155 ret = get_state_private(block_group_cache, start, &ptr);
156 if (ret)
157 return NULL;
158
159 block_group = (struct btrfs_block_group_cache *)(unsigned long)ptr;
160 if (block_group->key.objectid <= bytenr && bytenr <
161 block_group->key.objectid + block_group->key.offset)
162 return block_group;
163 return NULL;
164 }
165
166 static u64 noinline find_search_start(struct btrfs_root *root,
167 struct btrfs_block_group_cache **cache_ret,
168 u64 search_start, int num,
169 int data, int full_scan)
170 {
171 int ret;
172 struct btrfs_block_group_cache *cache = *cache_ret;
173 u64 last;
174 u64 start = 0;
175 u64 end = 0;
176 u64 cache_miss = 0;
177 int wrapped = 0;
178
179 if (!cache) {
180 goto out;
181 }
182 again:
183 ret = cache_block_group(root, cache);
184 if (ret)
185 goto out;
186
187 last = max(search_start, cache->key.objectid);
188
189 while(1) {
190 ret = find_first_extent_bit(&root->fs_info->free_space_cache,
191 last, &start, &end, EXTENT_DIRTY);
192 if (ret) {
193 if (!cache_miss)
194 cache_miss = last;
195 goto new_group;
196 }
197
198 start = max(last, start);
199 last = end + 1;
200 if (last - start < num) {
201 if (last == cache->key.objectid + cache->key.offset)
202 cache_miss = start;
203 continue;
204 }
205 if (data != BTRFS_BLOCK_GROUP_MIXED &&
206 start + num > cache->key.objectid + cache->key.offset)
207 goto new_group;
208 return start;
209 }
210 out:
211 cache = btrfs_lookup_block_group(root->fs_info, search_start);
212 if (!cache) {
213 printk("Unable to find block group for %Lu\n",
214 search_start);
215 WARN_ON(1);
216 return search_start;
217 }
218 return search_start;
219
220 new_group:
221 last = cache->key.objectid + cache->key.offset;
222 wrapped:
223 cache = btrfs_lookup_block_group(root->fs_info, last);
224 if (!cache) {
225 no_cache:
226 if (!wrapped) {
227 wrapped = 1;
228 last = search_start;
229 data = BTRFS_BLOCK_GROUP_MIXED;
230 goto wrapped;
231 }
232 goto out;
233 }
234 if (cache_miss && !cache->cached) {
235 cache_block_group(root, cache);
236 last = cache_miss;
237 cache = btrfs_lookup_block_group(root->fs_info, last);
238 }
239 cache = btrfs_find_block_group(root, cache, last, data, 0);
240 if (!cache)
241 goto no_cache;
242 *cache_ret = cache;
243 cache_miss = 0;
244 goto again;
245 }
246
247 static u64 div_factor(u64 num, int factor)
248 {
249 if (factor == 10)
250 return num;
251 num *= factor;
252 do_div(num, 10);
253 return num;
254 }
255
256 struct btrfs_block_group_cache *btrfs_find_block_group(struct btrfs_root *root,
257 struct btrfs_block_group_cache
258 *hint, u64 search_start,
259 int data, int owner)
260 {
261 struct btrfs_block_group_cache *cache;
262 struct extent_map_tree *block_group_cache;
263 struct btrfs_block_group_cache *found_group = NULL;
264 struct btrfs_fs_info *info = root->fs_info;
265 u64 used;
266 u64 last = 0;
267 u64 hint_last;
268 u64 start;
269 u64 end;
270 u64 free_check;
271 u64 ptr;
272 int bit;
273 int ret;
274 int full_search = 0;
275 int factor = 8;
276 int data_swap = 0;
277
278 block_group_cache = &info->block_group_cache;
279
280 if (!owner)
281 factor = 8;
282
283 if (data == BTRFS_BLOCK_GROUP_MIXED) {
284 bit = BLOCK_GROUP_DATA | BLOCK_GROUP_METADATA;
285 factor = 10;
286 } else if (data)
287 bit = BLOCK_GROUP_DATA;
288 else
289 bit = BLOCK_GROUP_METADATA;
290
291 if (search_start) {
292 struct btrfs_block_group_cache *shint;
293 shint = btrfs_lookup_block_group(info, search_start);
294 if (shint && (shint->data == data ||
295 shint->data == BTRFS_BLOCK_GROUP_MIXED)) {
296 used = btrfs_block_group_used(&shint->item);
297 if (used + shint->pinned <
298 div_factor(shint->key.offset, factor)) {
299 return shint;
300 }
301 }
302 }
303 if (hint && (hint->data == data ||
304 hint->data == BTRFS_BLOCK_GROUP_MIXED)) {
305 used = btrfs_block_group_used(&hint->item);
306 if (used + hint->pinned <
307 div_factor(hint->key.offset, factor)) {
308 return hint;
309 }
310 last = hint->key.objectid + hint->key.offset;
311 hint_last = last;
312 } else {
313 if (hint)
314 hint_last = max(hint->key.objectid, search_start);
315 else
316 hint_last = search_start;
317
318 last = hint_last;
319 }
320 again:
321 while(1) {
322 ret = find_first_extent_bit(block_group_cache, last,
323 &start, &end, bit);
324 if (ret)
325 break;
326
327 ret = get_state_private(block_group_cache, start, &ptr);
328 if (ret)
329 break;
330
331 cache = (struct btrfs_block_group_cache *)(unsigned long)ptr;
332 last = cache->key.objectid + cache->key.offset;
333 used = btrfs_block_group_used(&cache->item);
334
335 if (full_search)
336 free_check = cache->key.offset;
337 else
338 free_check = div_factor(cache->key.offset, factor);
339 if (used + cache->pinned < free_check) {
340 found_group = cache;
341 goto found;
342 }
343 cond_resched();
344 }
345 if (!full_search) {
346 last = search_start;
347 full_search = 1;
348 goto again;
349 }
350 if (!data_swap) {
351 data_swap = 1;
352 bit = BLOCK_GROUP_DATA | BLOCK_GROUP_METADATA;
353 last = search_start;
354 goto again;
355 }
356 found:
357 return found_group;
358 }
359
360 static u64 hash_extent_ref(u64 root_objectid, u64 ref_generation,
361 u64 owner, u64 owner_offset)
362 {
363 u32 high_crc = ~(u32)0;
364 u32 low_crc = ~(u32)0;
365 __le64 lenum;
366
367 lenum = cpu_to_le64(root_objectid);
368 high_crc = crc32c(high_crc, &lenum, sizeof(lenum));
369 lenum = cpu_to_le64(ref_generation);
370 low_crc = crc32c(low_crc, &lenum, sizeof(lenum));
371
372 #if 0
373 lenum = cpu_to_le64(owner);
374 low_crc = crc32c(low_crc, &lenum, sizeof(lenum));
375 lenum = cpu_to_le64(owner_offset);
376 low_crc = crc32c(low_crc, &lenum, sizeof(lenum));
377 #endif
378 return ((u64)high_crc << 32) | (u64)low_crc;
379 }
380
381 static int match_extent_ref(struct extent_buffer *leaf,
382 struct btrfs_extent_ref *disk_ref,
383 struct btrfs_extent_ref *cpu_ref)
384 {
385 int ret;
386 int len;
387
388 if (cpu_ref->objectid)
389 len = sizeof(*cpu_ref);
390 else
391 len = 2 * sizeof(u64);
392 ret = memcmp_extent_buffer(leaf, cpu_ref, (unsigned long)disk_ref,
393 len);
394 return ret == 0;
395 }
396
397 static int noinline lookup_extent_backref(struct btrfs_trans_handle *trans,
398 struct btrfs_root *root,
399 struct btrfs_path *path, u64 bytenr,
400 u64 root_objectid,
401 u64 ref_generation, u64 owner,
402 u64 owner_offset, int del)
403 {
404 u64 hash;
405 struct btrfs_key key;
406 struct btrfs_key found_key;
407 struct btrfs_extent_ref ref;
408 struct extent_buffer *leaf;
409 struct btrfs_extent_ref *disk_ref;
410 int ret;
411 int ret2;
412
413 btrfs_set_stack_ref_root(&ref, root_objectid);
414 btrfs_set_stack_ref_generation(&ref, ref_generation);
415 btrfs_set_stack_ref_objectid(&ref, owner);
416 btrfs_set_stack_ref_offset(&ref, owner_offset);
417
418 hash = hash_extent_ref(root_objectid, ref_generation, owner,
419 owner_offset);
420 key.offset = hash;
421 key.objectid = bytenr;
422 key.type = BTRFS_EXTENT_REF_KEY;
423
424 while (1) {
425 ret = btrfs_search_slot(trans, root, &key, path,
426 del ? -1 : 0, del);
427 if (ret < 0)
428 goto out;
429 leaf = path->nodes[0];
430 if (ret != 0) {
431 u32 nritems = btrfs_header_nritems(leaf);
432 if (path->slots[0] >= nritems) {
433 ret2 = btrfs_next_leaf(root, path);
434 if (ret2)
435 goto out;
436 leaf = path->nodes[0];
437 }
438 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
439 if (found_key.objectid != bytenr ||
440 found_key.type != BTRFS_EXTENT_REF_KEY)
441 goto out;
442 key.offset = found_key.offset;
443 if (del) {
444 btrfs_release_path(root, path);
445 continue;
446 }
447 }
448 disk_ref = btrfs_item_ptr(path->nodes[0],
449 path->slots[0],
450 struct btrfs_extent_ref);
451 if (match_extent_ref(path->nodes[0], disk_ref, &ref)) {
452 ret = 0;
453 goto out;
454 }
455 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
456 key.offset = found_key.offset + 1;
457 btrfs_release_path(root, path);
458 }
459 out:
460 return ret;
461 }
462
463 /*
464 * Back reference rules. Back refs have three main goals:
465 *
466 * 1) differentiate between all holders of references to an extent so that
467 * when a reference is dropped we can make sure it was a valid reference
468 * before freeing the extent.
469 *
470 * 2) Provide enough information to quickly find the holders of an extent
471 * if we notice a given block is corrupted or bad.
472 *
473 * 3) Make it easy to migrate blocks for FS shrinking or storage pool
474 * maintenance. This is actually the same as #2, but with a slightly
475 * different use case.
476 *
477 * File extents can be referenced by:
478 *
479 * - multiple snapshots, subvolumes, or different generations in one subvol
480 * - different files inside a single subvolume (in theory, not implemented yet)
481 * - different offsets inside a file (bookend extents in file.c)
482 *
483 * The extent ref structure has fields for:
484 *
485 * - Objectid of the subvolume root
486 * - Generation number of the tree holding the reference
487 * - objectid of the file holding the reference
488 * - offset in the file corresponding to the key holding the reference
489 *
490 * When a file extent is allocated the fields are filled in:
491 * (root_key.objectid, trans->transid, inode objectid, offset in file)
492 *
493 * When a leaf is cow'd new references are added for every file extent found
494 * in the leaf. It looks the same as the create case, but trans->transid
495 * will be different when the block is cow'd.
496 *
497 * (root_key.objectid, trans->transid, inode objectid, offset in file)
498 *
499 * When a file extent is removed either during snapshot deletion or file
500 * truncation, the corresponding back reference is found
501 * by searching for:
502 *
503 * (btrfs_header_owner(leaf), btrfs_header_generation(leaf),
504 * inode objectid, offset in file)
505 *
506 * Btree extents can be referenced by:
507 *
508 * - Different subvolumes
509 * - Different generations of the same subvolume
510 *
511 * Storing sufficient information for a full reverse mapping of a btree
512 * block would require storing the lowest key of the block in the backref,
513 * and it would require updating that lowest key either before write out or
514 * every time it changed. Instead, the objectid of the lowest key is stored
515 * along with the level of the tree block. This provides a hint
516 * about where in the btree the block can be found. Searches through the
517 * btree only need to look for a pointer to that block, so they stop one
518 * level higher than the level recorded in the backref.
519 *
520 * Some btrees do not do reference counting on their extents. These
521 * include the extent tree and the tree of tree roots. Backrefs for these
522 * trees always have a generation of zero.
523 *
524 * When a tree block is created, back references are inserted:
525 *
526 * (root->root_key.objectid, trans->transid or zero, level, lowest_key_objectid)
527 *
528 * When a tree block is cow'd in a reference counted root,
529 * new back references are added for all the blocks it points to.
530 * These are of the form (trans->transid will have increased since creation):
531 *
532 * (root->root_key.objectid, trans->transid, level, lowest_key_objectid)
533 *
534 * Because the lowest_key_objectid and the level are just hints
535 * they are not used when backrefs are deleted. When a backref is deleted:
536 *
537 * if backref was for a tree root:
538 * root_objectid = root->root_key.objectid
539 * else
540 * root_objectid = btrfs_header_owner(parent)
541 *
542 * (root_objectid, btrfs_header_generation(parent) or zero, 0, 0)
543 *
544 * Back Reference Key hashing:
545 *
546 * Back references have four fields, each 64 bits long. Unfortunately,
547 * This is hashed into a single 64 bit number and placed into the key offset.
548 * The key objectid corresponds to the first byte in the extent, and the
549 * key type is set to BTRFS_EXTENT_REF_KEY
550 */
551 int btrfs_insert_extent_backref(struct btrfs_trans_handle *trans,
552 struct btrfs_root *root,
553 struct btrfs_path *path, u64 bytenr,
554 u64 root_objectid, u64 ref_generation,
555 u64 owner, u64 owner_offset)
556 {
557 u64 hash;
558 struct btrfs_key key;
559 struct btrfs_extent_ref ref;
560 struct btrfs_extent_ref *disk_ref;
561 int ret;
562
563 btrfs_set_stack_ref_root(&ref, root_objectid);
564 btrfs_set_stack_ref_generation(&ref, ref_generation);
565 btrfs_set_stack_ref_objectid(&ref, owner);
566 btrfs_set_stack_ref_offset(&ref, owner_offset);
567
568 hash = hash_extent_ref(root_objectid, ref_generation, owner,
569 owner_offset);
570 key.offset = hash;
571 key.objectid = bytenr;
572 key.type = BTRFS_EXTENT_REF_KEY;
573
574 ret = btrfs_insert_empty_item(trans, root, path, &key, sizeof(ref));
575 while (ret == -EEXIST) {
576 disk_ref = btrfs_item_ptr(path->nodes[0], path->slots[0],
577 struct btrfs_extent_ref);
578 if (match_extent_ref(path->nodes[0], disk_ref, &ref))
579 goto out;
580 key.offset++;
581 btrfs_release_path(root, path);
582 ret = btrfs_insert_empty_item(trans, root, path, &key,
583 sizeof(ref));
584 }
585 if (ret)
586 goto out;
587 disk_ref = btrfs_item_ptr(path->nodes[0], path->slots[0],
588 struct btrfs_extent_ref);
589 write_extent_buffer(path->nodes[0], &ref, (unsigned long)disk_ref,
590 sizeof(ref));
591 btrfs_mark_buffer_dirty(path->nodes[0]);
592 out:
593 btrfs_release_path(root, path);
594 return ret;
595 }
596
597 int btrfs_inc_extent_ref(struct btrfs_trans_handle *trans,
598 struct btrfs_root *root,
599 u64 bytenr, u64 num_bytes,
600 u64 root_objectid, u64 ref_generation,
601 u64 owner, u64 owner_offset)
602 {
603 struct btrfs_path *path;
604 int ret;
605 struct btrfs_key key;
606 struct extent_buffer *l;
607 struct btrfs_extent_item *item;
608 u32 refs;
609
610 WARN_ON(num_bytes < root->sectorsize);
611 path = btrfs_alloc_path();
612 if (!path)
613 return -ENOMEM;
614
615 key.objectid = bytenr;
616 btrfs_set_key_type(&key, BTRFS_EXTENT_ITEM_KEY);
617 key.offset = num_bytes;
618 ret = btrfs_search_slot(trans, root->fs_info->extent_root, &key, path,
619 0, 1);
620 if (ret < 0)
621 return ret;
622 if (ret != 0) {
623 BUG();
624 }
625 BUG_ON(ret != 0);
626 l = path->nodes[0];
627 item = btrfs_item_ptr(l, path->slots[0], struct btrfs_extent_item);
628 refs = btrfs_extent_refs(l, item);
629 btrfs_set_extent_refs(l, item, refs + 1);
630 btrfs_mark_buffer_dirty(path->nodes[0]);
631
632 btrfs_release_path(root->fs_info->extent_root, path);
633
634 ret = btrfs_insert_extent_backref(trans, root->fs_info->extent_root,
635 path, bytenr, root_objectid,
636 ref_generation, owner, owner_offset);
637 BUG_ON(ret);
638 finish_current_insert(trans, root->fs_info->extent_root);
639 del_pending_extents(trans, root->fs_info->extent_root);
640
641 btrfs_free_path(path);
642 return 0;
643 }
644
645 int btrfs_extent_post_op(struct btrfs_trans_handle *trans,
646 struct btrfs_root *root)
647 {
648 finish_current_insert(trans, root->fs_info->extent_root);
649 del_pending_extents(trans, root->fs_info->extent_root);
650 return 0;
651 }
652
653 static int lookup_extent_ref(struct btrfs_trans_handle *trans,
654 struct btrfs_root *root, u64 bytenr,
655 u64 num_bytes, u32 *refs)
656 {
657 struct btrfs_path *path;
658 int ret;
659 struct btrfs_key key;
660 struct extent_buffer *l;
661 struct btrfs_extent_item *item;
662
663 WARN_ON(num_bytes < root->sectorsize);
664 path = btrfs_alloc_path();
665 key.objectid = bytenr;
666 key.offset = num_bytes;
667 btrfs_set_key_type(&key, BTRFS_EXTENT_ITEM_KEY);
668 ret = btrfs_search_slot(trans, root->fs_info->extent_root, &key, path,
669 0, 0);
670 if (ret < 0)
671 goto out;
672 if (ret != 0) {
673 btrfs_print_leaf(root, path->nodes[0]);
674 printk("failed to find block number %Lu\n", bytenr);
675 BUG();
676 }
677 l = path->nodes[0];
678 item = btrfs_item_ptr(l, path->slots[0], struct btrfs_extent_item);
679 *refs = btrfs_extent_refs(l, item);
680 out:
681 btrfs_free_path(path);
682 return 0;
683 }
684
685 u32 btrfs_count_snapshots_in_path(struct btrfs_root *root,
686 struct btrfs_path *count_path,
687 u64 first_extent)
688 {
689 struct btrfs_root *extent_root = root->fs_info->extent_root;
690 struct btrfs_path *path;
691 u64 bytenr;
692 u64 found_objectid;
693 u64 root_objectid = root->root_key.objectid;
694 u32 total_count = 0;
695 u32 cur_count;
696 u32 nritems;
697 int ret;
698 struct btrfs_key key;
699 struct btrfs_key found_key;
700 struct extent_buffer *l;
701 struct btrfs_extent_item *item;
702 struct btrfs_extent_ref *ref_item;
703 int level = -1;
704
705 path = btrfs_alloc_path();
706 again:
707 if (level == -1)
708 bytenr = first_extent;
709 else
710 bytenr = count_path->nodes[level]->start;
711
712 cur_count = 0;
713 key.objectid = bytenr;
714 key.offset = 0;
715
716 btrfs_set_key_type(&key, BTRFS_EXTENT_ITEM_KEY);
717 ret = btrfs_search_slot(NULL, extent_root, &key, path, 0, 0);
718 if (ret < 0)
719 goto out;
720 BUG_ON(ret == 0);
721
722 l = path->nodes[0];
723 btrfs_item_key_to_cpu(l, &found_key, path->slots[0]);
724
725 if (found_key.objectid != bytenr ||
726 found_key.type != BTRFS_EXTENT_ITEM_KEY) {
727 goto out;
728 }
729
730 item = btrfs_item_ptr(l, path->slots[0], struct btrfs_extent_item);
731 while (1) {
732 l = path->nodes[0];
733 nritems = btrfs_header_nritems(l);
734 if (path->slots[0] >= nritems) {
735 ret = btrfs_next_leaf(extent_root, path);
736 if (ret == 0)
737 continue;
738 break;
739 }
740 btrfs_item_key_to_cpu(l, &found_key, path->slots[0]);
741 if (found_key.objectid != bytenr)
742 break;
743
744 if (found_key.type != BTRFS_EXTENT_REF_KEY) {
745 path->slots[0]++;
746 continue;
747 }
748
749 cur_count++;
750 ref_item = btrfs_item_ptr(l, path->slots[0],
751 struct btrfs_extent_ref);
752 found_objectid = btrfs_ref_root(l, ref_item);
753
754 if (found_objectid != root_objectid) {
755 total_count = 2;
756 goto out;
757 }
758 total_count = 1;
759 path->slots[0]++;
760 }
761 if (cur_count == 0) {
762 total_count = 0;
763 goto out;
764 }
765 if (level >= 0 && root->node == count_path->nodes[level])
766 goto out;
767 level++;
768 btrfs_release_path(root, path);
769 goto again;
770
771 out:
772 btrfs_free_path(path);
773 return total_count;
774
775 }
776
777 int btrfs_inc_root_ref(struct btrfs_trans_handle *trans,
778 struct btrfs_root *root, u64 owner_objectid)
779 {
780 u64 generation;
781 u64 key_objectid;
782 u64 level;
783 u32 nritems;
784 struct btrfs_disk_key disk_key;
785
786 level = btrfs_header_level(root->node);
787 generation = trans->transid;
788 nritems = btrfs_header_nritems(root->node);
789 if (nritems > 0) {
790 if (level == 0)
791 btrfs_item_key(root->node, &disk_key, 0);
792 else
793 btrfs_node_key(root->node, &disk_key, 0);
794 key_objectid = btrfs_disk_key_objectid(&disk_key);
795 } else {
796 key_objectid = 0;
797 }
798 return btrfs_inc_extent_ref(trans, root, root->node->start,
799 root->node->len, owner_objectid,
800 generation, level, key_objectid);
801 }
802
803 int btrfs_inc_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root,
804 struct extent_buffer *buf)
805 {
806 u64 bytenr;
807 u32 nritems;
808 struct btrfs_key key;
809 struct btrfs_file_extent_item *fi;
810 int i;
811 int level;
812 int ret;
813 int faili;
814
815 if (!root->ref_cows)
816 return 0;
817
818 level = btrfs_header_level(buf);
819 nritems = btrfs_header_nritems(buf);
820 for (i = 0; i < nritems; i++) {
821 if (level == 0) {
822 u64 disk_bytenr;
823 btrfs_item_key_to_cpu(buf, &key, i);
824 if (btrfs_key_type(&key) != BTRFS_EXTENT_DATA_KEY)
825 continue;
826 fi = btrfs_item_ptr(buf, i,
827 struct btrfs_file_extent_item);
828 if (btrfs_file_extent_type(buf, fi) ==
829 BTRFS_FILE_EXTENT_INLINE)
830 continue;
831 disk_bytenr = btrfs_file_extent_disk_bytenr(buf, fi);
832 if (disk_bytenr == 0)
833 continue;
834 ret = btrfs_inc_extent_ref(trans, root, disk_bytenr,
835 btrfs_file_extent_disk_num_bytes(buf, fi),
836 root->root_key.objectid, trans->transid,
837 key.objectid, key.offset);
838 if (ret) {
839 faili = i;
840 goto fail;
841 }
842 } else {
843 bytenr = btrfs_node_blockptr(buf, i);
844 btrfs_node_key_to_cpu(buf, &key, i);
845 ret = btrfs_inc_extent_ref(trans, root, bytenr,
846 btrfs_level_size(root, level - 1),
847 root->root_key.objectid,
848 trans->transid,
849 level - 1, key.objectid);
850 if (ret) {
851 faili = i;
852 goto fail;
853 }
854 }
855 }
856 return 0;
857 fail:
858 WARN_ON(1);
859 #if 0
860 for (i =0; i < faili; i++) {
861 if (level == 0) {
862 u64 disk_bytenr;
863 btrfs_item_key_to_cpu(buf, &key, i);
864 if (btrfs_key_type(&key) != BTRFS_EXTENT_DATA_KEY)
865 continue;
866 fi = btrfs_item_ptr(buf, i,
867 struct btrfs_file_extent_item);
868 if (btrfs_file_extent_type(buf, fi) ==
869 BTRFS_FILE_EXTENT_INLINE)
870 continue;
871 disk_bytenr = btrfs_file_extent_disk_bytenr(buf, fi);
872 if (disk_bytenr == 0)
873 continue;
874 err = btrfs_free_extent(trans, root, disk_bytenr,
875 btrfs_file_extent_disk_num_bytes(buf,
876 fi), 0);
877 BUG_ON(err);
878 } else {
879 bytenr = btrfs_node_blockptr(buf, i);
880 err = btrfs_free_extent(trans, root, bytenr,
881 btrfs_level_size(root, level - 1), 0);
882 BUG_ON(err);
883 }
884 }
885 #endif
886 return ret;
887 }
888
889 static int write_one_cache_group(struct btrfs_trans_handle *trans,
890 struct btrfs_root *root,
891 struct btrfs_path *path,
892 struct btrfs_block_group_cache *cache)
893 {
894 int ret;
895 int pending_ret;
896 struct btrfs_root *extent_root = root->fs_info->extent_root;
897 unsigned long bi;
898 struct extent_buffer *leaf;
899
900 ret = btrfs_search_slot(trans, extent_root, &cache->key, path, 0, 1);
901 if (ret < 0)
902 goto fail;
903 BUG_ON(ret);
904
905 leaf = path->nodes[0];
906 bi = btrfs_item_ptr_offset(leaf, path->slots[0]);
907 write_extent_buffer(leaf, &cache->item, bi, sizeof(cache->item));
908 btrfs_mark_buffer_dirty(leaf);
909 btrfs_release_path(extent_root, path);
910 fail:
911 finish_current_insert(trans, extent_root);
912 pending_ret = del_pending_extents(trans, extent_root);
913 if (ret)
914 return ret;
915 if (pending_ret)
916 return pending_ret;
917 return 0;
918
919 }
920
921 int btrfs_write_dirty_block_groups(struct btrfs_trans_handle *trans,
922 struct btrfs_root *root)
923 {
924 struct extent_map_tree *block_group_cache;
925 struct btrfs_block_group_cache *cache;
926 int ret;
927 int err = 0;
928 int werr = 0;
929 struct btrfs_path *path;
930 u64 last = 0;
931 u64 start;
932 u64 end;
933 u64 ptr;
934
935 block_group_cache = &root->fs_info->block_group_cache;
936 path = btrfs_alloc_path();
937 if (!path)
938 return -ENOMEM;
939
940 while(1) {
941 ret = find_first_extent_bit(block_group_cache, last,
942 &start, &end, BLOCK_GROUP_DIRTY);
943 if (ret)
944 break;
945
946 last = end + 1;
947 ret = get_state_private(block_group_cache, start, &ptr);
948 if (ret)
949 break;
950
951 cache = (struct btrfs_block_group_cache *)(unsigned long)ptr;
952 err = write_one_cache_group(trans, root,
953 path, cache);
954 /*
955 * if we fail to write the cache group, we want
956 * to keep it marked dirty in hopes that a later
957 * write will work
958 */
959 if (err) {
960 werr = err;
961 continue;
962 }
963 clear_extent_bits(block_group_cache, start, end,
964 BLOCK_GROUP_DIRTY, GFP_NOFS);
965 }
966 btrfs_free_path(path);
967 return werr;
968 }
969
970 static int update_block_group(struct btrfs_trans_handle *trans,
971 struct btrfs_root *root,
972 u64 bytenr, u64 num_bytes, int alloc,
973 int mark_free, int data)
974 {
975 struct btrfs_block_group_cache *cache;
976 struct btrfs_fs_info *info = root->fs_info;
977 u64 total = num_bytes;
978 u64 old_val;
979 u64 byte_in_group;
980 u64 start;
981 u64 end;
982
983 while(total) {
984 cache = btrfs_lookup_block_group(info, bytenr);
985 if (!cache) {
986 return -1;
987 }
988 byte_in_group = bytenr - cache->key.objectid;
989 WARN_ON(byte_in_group > cache->key.offset);
990 start = cache->key.objectid;
991 end = start + cache->key.offset - 1;
992 set_extent_bits(&info->block_group_cache, start, end,
993 BLOCK_GROUP_DIRTY, GFP_NOFS);
994
995 old_val = btrfs_block_group_used(&cache->item);
996 num_bytes = min(total, cache->key.offset - byte_in_group);
997 if (alloc) {
998 if (cache->data != data &&
999 old_val < (cache->key.offset >> 1)) {
1000 int bit_to_clear;
1001 int bit_to_set;
1002 cache->data = data;
1003 if (data) {
1004 bit_to_clear = BLOCK_GROUP_METADATA;
1005 bit_to_set = BLOCK_GROUP_DATA;
1006 cache->item.flags &=
1007 ~BTRFS_BLOCK_GROUP_MIXED;
1008 cache->item.flags |=
1009 BTRFS_BLOCK_GROUP_DATA;
1010 } else {
1011 bit_to_clear = BLOCK_GROUP_DATA;
1012 bit_to_set = BLOCK_GROUP_METADATA;
1013 cache->item.flags &=
1014 ~BTRFS_BLOCK_GROUP_MIXED;
1015 cache->item.flags &=
1016 ~BTRFS_BLOCK_GROUP_DATA;
1017 }
1018 clear_extent_bits(&info->block_group_cache,
1019 start, end, bit_to_clear,
1020 GFP_NOFS);
1021 set_extent_bits(&info->block_group_cache,
1022 start, end, bit_to_set,
1023 GFP_NOFS);
1024 } else if (cache->data != data &&
1025 cache->data != BTRFS_BLOCK_GROUP_MIXED) {
1026 cache->data = BTRFS_BLOCK_GROUP_MIXED;
1027 set_extent_bits(&info->block_group_cache,
1028 start, end,
1029 BLOCK_GROUP_DATA |
1030 BLOCK_GROUP_METADATA,
1031 GFP_NOFS);
1032 }
1033 old_val += num_bytes;
1034 } else {
1035 old_val -= num_bytes;
1036 if (mark_free) {
1037 set_extent_dirty(&info->free_space_cache,
1038 bytenr, bytenr + num_bytes - 1,
1039 GFP_NOFS);
1040 }
1041 }
1042 btrfs_set_block_group_used(&cache->item, old_val);
1043 total -= num_bytes;
1044 bytenr += num_bytes;
1045 }
1046 return 0;
1047 }
1048 static int update_pinned_extents(struct btrfs_root *root,
1049 u64 bytenr, u64 num, int pin)
1050 {
1051 u64 len;
1052 struct btrfs_block_group_cache *cache;
1053 struct btrfs_fs_info *fs_info = root->fs_info;
1054
1055 if (pin) {
1056 set_extent_dirty(&fs_info->pinned_extents,
1057 bytenr, bytenr + num - 1, GFP_NOFS);
1058 } else {
1059 clear_extent_dirty(&fs_info->pinned_extents,
1060 bytenr, bytenr + num - 1, GFP_NOFS);
1061 }
1062 while (num > 0) {
1063 cache = btrfs_lookup_block_group(fs_info, bytenr);
1064 WARN_ON(!cache);
1065 len = min(num, cache->key.offset -
1066 (bytenr - cache->key.objectid));
1067 if (pin) {
1068 cache->pinned += len;
1069 fs_info->total_pinned += len;
1070 } else {
1071 cache->pinned -= len;
1072 fs_info->total_pinned -= len;
1073 }
1074 bytenr += len;
1075 num -= len;
1076 }
1077 return 0;
1078 }
1079
1080 int btrfs_copy_pinned(struct btrfs_root *root, struct extent_map_tree *copy)
1081 {
1082 u64 last = 0;
1083 u64 start;
1084 u64 end;
1085 struct extent_map_tree *pinned_extents = &root->fs_info->pinned_extents;
1086 int ret;
1087
1088 while(1) {
1089 ret = find_first_extent_bit(pinned_extents, last,
1090 &start, &end, EXTENT_DIRTY);
1091 if (ret)
1092 break;
1093 set_extent_dirty(copy, start, end, GFP_NOFS);
1094 last = end + 1;
1095 }
1096 return 0;
1097 }
1098
1099 int btrfs_finish_extent_commit(struct btrfs_trans_handle *trans,
1100 struct btrfs_root *root,
1101 struct extent_map_tree *unpin)
1102 {
1103 u64 start;
1104 u64 end;
1105 int ret;
1106 struct extent_map_tree *free_space_cache;
1107 free_space_cache = &root->fs_info->free_space_cache;
1108
1109 while(1) {
1110 ret = find_first_extent_bit(unpin, 0, &start, &end,
1111 EXTENT_DIRTY);
1112 if (ret)
1113 break;
1114 update_pinned_extents(root, start, end + 1 - start, 0);
1115 clear_extent_dirty(unpin, start, end, GFP_NOFS);
1116 set_extent_dirty(free_space_cache, start, end, GFP_NOFS);
1117 }
1118 return 0;
1119 }
1120
1121 static int finish_current_insert(struct btrfs_trans_handle *trans,
1122 struct btrfs_root *extent_root)
1123 {
1124 u64 start;
1125 u64 end;
1126 struct btrfs_fs_info *info = extent_root->fs_info;
1127 struct extent_buffer *eb;
1128 struct btrfs_path *path;
1129 struct btrfs_key ins;
1130 struct btrfs_disk_key first;
1131 struct btrfs_extent_item extent_item;
1132 int ret;
1133 int level;
1134 int err = 0;
1135
1136 btrfs_set_stack_extent_refs(&extent_item, 1);
1137 btrfs_set_key_type(&ins, BTRFS_EXTENT_ITEM_KEY);
1138 path = btrfs_alloc_path();
1139
1140 while(1) {
1141 ret = find_first_extent_bit(&info->extent_ins, 0, &start,
1142 &end, EXTENT_LOCKED);
1143 if (ret)
1144 break;
1145
1146 ins.objectid = start;
1147 ins.offset = end + 1 - start;
1148 err = btrfs_insert_item(trans, extent_root, &ins,
1149 &extent_item, sizeof(extent_item));
1150 clear_extent_bits(&info->extent_ins, start, end, EXTENT_LOCKED,
1151 GFP_NOFS);
1152 eb = read_tree_block(extent_root, ins.objectid, ins.offset);
1153 level = btrfs_header_level(eb);
1154 if (level == 0) {
1155 btrfs_item_key(eb, &first, 0);
1156 } else {
1157 btrfs_node_key(eb, &first, 0);
1158 }
1159 err = btrfs_insert_extent_backref(trans, extent_root, path,
1160 start, extent_root->root_key.objectid,
1161 0, level,
1162 btrfs_disk_key_objectid(&first));
1163 BUG_ON(err);
1164 free_extent_buffer(eb);
1165 }
1166 btrfs_free_path(path);
1167 return 0;
1168 }
1169
1170 static int pin_down_bytes(struct btrfs_root *root, u64 bytenr, u32 num_bytes,
1171 int pending)
1172 {
1173 int err = 0;
1174 struct extent_buffer *buf;
1175
1176 if (!pending) {
1177 buf = btrfs_find_tree_block(root, bytenr, num_bytes);
1178 if (buf) {
1179 if (btrfs_buffer_uptodate(buf)) {
1180 u64 transid =
1181 root->fs_info->running_transaction->transid;
1182 if (btrfs_header_generation(buf) == transid) {
1183 free_extent_buffer(buf);
1184 return 1;
1185 }
1186 }
1187 free_extent_buffer(buf);
1188 }
1189 update_pinned_extents(root, bytenr, num_bytes, 1);
1190 } else {
1191 set_extent_bits(&root->fs_info->pending_del,
1192 bytenr, bytenr + num_bytes - 1,
1193 EXTENT_LOCKED, GFP_NOFS);
1194 }
1195 BUG_ON(err < 0);
1196 return 0;
1197 }
1198
1199 /*
1200 * remove an extent from the root, returns 0 on success
1201 */
1202 static int __free_extent(struct btrfs_trans_handle *trans, struct btrfs_root
1203 *root, u64 bytenr, u64 num_bytes,
1204 u64 root_objectid, u64 ref_generation,
1205 u64 owner_objectid, u64 owner_offset, int pin,
1206 int mark_free)
1207 {
1208 struct btrfs_path *path;
1209 struct btrfs_key key;
1210 struct btrfs_fs_info *info = root->fs_info;
1211 struct btrfs_root *extent_root = info->extent_root;
1212 struct extent_buffer *leaf;
1213 int ret;
1214 struct btrfs_extent_item *ei;
1215 u32 refs;
1216
1217 key.objectid = bytenr;
1218 btrfs_set_key_type(&key, BTRFS_EXTENT_ITEM_KEY);
1219 key.offset = num_bytes;
1220
1221 path = btrfs_alloc_path();
1222 if (!path)
1223 return -ENOMEM;
1224
1225 ret = lookup_extent_backref(trans, extent_root, path,
1226 bytenr, root_objectid,
1227 ref_generation,
1228 owner_objectid, owner_offset, 1);
1229 if (ret == 0) {
1230 ret = btrfs_del_item(trans, extent_root, path);
1231 } else {
1232 btrfs_print_leaf(extent_root, path->nodes[0]);
1233 WARN_ON(1);
1234 printk("Unable to find ref byte nr %Lu root %Lu "
1235 " gen %Lu owner %Lu offset %Lu\n", bytenr,
1236 root_objectid, ref_generation, owner_objectid,
1237 owner_offset);
1238 }
1239 btrfs_release_path(extent_root, path);
1240 ret = btrfs_search_slot(trans, extent_root, &key, path, -1, 1);
1241 if (ret < 0)
1242 return ret;
1243 BUG_ON(ret);
1244
1245 leaf = path->nodes[0];
1246 ei = btrfs_item_ptr(leaf, path->slots[0],
1247 struct btrfs_extent_item);
1248 refs = btrfs_extent_refs(leaf, ei);
1249 BUG_ON(refs == 0);
1250 refs -= 1;
1251 btrfs_set_extent_refs(leaf, ei, refs);
1252 btrfs_mark_buffer_dirty(leaf);
1253
1254 if (refs == 0) {
1255 u64 super_used;
1256 u64 root_used;
1257
1258 if (pin) {
1259 ret = pin_down_bytes(root, bytenr, num_bytes, 0);
1260 if (ret > 0)
1261 mark_free = 1;
1262 BUG_ON(ret < 0);
1263 }
1264
1265 /* block accounting for super block */
1266 super_used = btrfs_super_bytes_used(&info->super_copy);
1267 btrfs_set_super_bytes_used(&info->super_copy,
1268 super_used - num_bytes);
1269
1270 /* block accounting for root item */
1271 root_used = btrfs_root_used(&root->root_item);
1272 btrfs_set_root_used(&root->root_item,
1273 root_used - num_bytes);
1274
1275 ret = btrfs_del_item(trans, extent_root, path);
1276 if (ret) {
1277 return ret;
1278 }
1279 ret = update_block_group(trans, root, bytenr, num_bytes, 0,
1280 mark_free, 0);
1281 BUG_ON(ret);
1282 }
1283 btrfs_free_path(path);
1284 finish_current_insert(trans, extent_root);
1285 return ret;
1286 }
1287
1288 /*
1289 * find all the blocks marked as pending in the radix tree and remove
1290 * them from the extent map
1291 */
1292 static int del_pending_extents(struct btrfs_trans_handle *trans, struct
1293 btrfs_root *extent_root)
1294 {
1295 int ret;
1296 int err = 0;
1297 u64 start;
1298 u64 end;
1299 struct extent_map_tree *pending_del;
1300 struct extent_map_tree *pinned_extents;
1301
1302 pending_del = &extent_root->fs_info->pending_del;
1303 pinned_extents = &extent_root->fs_info->pinned_extents;
1304
1305 while(1) {
1306 ret = find_first_extent_bit(pending_del, 0, &start, &end,
1307 EXTENT_LOCKED);
1308 if (ret)
1309 break;
1310 update_pinned_extents(extent_root, start, end + 1 - start, 1);
1311 clear_extent_bits(pending_del, start, end, EXTENT_LOCKED,
1312 GFP_NOFS);
1313 ret = __free_extent(trans, extent_root,
1314 start, end + 1 - start,
1315 extent_root->root_key.objectid,
1316 0, 0, 0, 0, 0);
1317 if (ret)
1318 err = ret;
1319 }
1320 return err;
1321 }
1322
1323 /*
1324 * remove an extent from the root, returns 0 on success
1325 */
1326 int btrfs_free_extent(struct btrfs_trans_handle *trans, struct btrfs_root
1327 *root, u64 bytenr, u64 num_bytes,
1328 u64 root_objectid, u64 ref_generation,
1329 u64 owner_objectid, u64 owner_offset, int pin)
1330 {
1331 struct btrfs_root *extent_root = root->fs_info->extent_root;
1332 int pending_ret;
1333 int ret;
1334
1335 WARN_ON(num_bytes < root->sectorsize);
1336 if (!root->ref_cows)
1337 ref_generation = 0;
1338
1339 if (root == extent_root) {
1340 pin_down_bytes(root, bytenr, num_bytes, 1);
1341 return 0;
1342 }
1343 ret = __free_extent(trans, root, bytenr, num_bytes, root_objectid,
1344 ref_generation, owner_objectid, owner_offset,
1345 pin, pin == 0);
1346 pending_ret = del_pending_extents(trans, root->fs_info->extent_root);
1347 return ret ? ret : pending_ret;
1348 }
1349
1350 static u64 stripe_align(struct btrfs_root *root, u64 val)
1351 {
1352 u64 mask = ((u64)root->stripesize - 1);
1353 u64 ret = (val + mask) & ~mask;
1354 return ret;
1355 }
1356
1357 /*
1358 * walks the btree of allocated extents and find a hole of a given size.
1359 * The key ins is changed to record the hole:
1360 * ins->objectid == block start
1361 * ins->flags = BTRFS_EXTENT_ITEM_KEY
1362 * ins->offset == number of blocks
1363 * Any available blocks before search_start are skipped.
1364 */
1365 static int noinline find_free_extent(struct btrfs_trans_handle *trans,
1366 struct btrfs_root *orig_root,
1367 u64 num_bytes, u64 empty_size,
1368 u64 search_start, u64 search_end,
1369 u64 hint_byte, struct btrfs_key *ins,
1370 u64 exclude_start, u64 exclude_nr,
1371 int data)
1372 {
1373 struct btrfs_path *path;
1374 struct btrfs_key key;
1375 u64 hole_size = 0;
1376 u64 aligned;
1377 int ret;
1378 int slot = 0;
1379 u64 last_byte = 0;
1380 u64 orig_search_start = search_start;
1381 int start_found;
1382 struct extent_buffer *l;
1383 struct btrfs_root * root = orig_root->fs_info->extent_root;
1384 struct btrfs_fs_info *info = root->fs_info;
1385 u64 total_needed = num_bytes;
1386 int level;
1387 struct btrfs_block_group_cache *block_group;
1388 int full_scan = 0;
1389 int wrapped = 0;
1390 u64 cached_start;
1391
1392 WARN_ON(num_bytes < root->sectorsize);
1393 btrfs_set_key_type(ins, BTRFS_EXTENT_ITEM_KEY);
1394
1395 level = btrfs_header_level(root->node);
1396
1397 if (num_bytes >= 32 * 1024 * 1024 && hint_byte) {
1398 data = BTRFS_BLOCK_GROUP_MIXED;
1399 }
1400
1401 if (search_end == (u64)-1)
1402 search_end = btrfs_super_total_bytes(&info->super_copy);
1403 if (hint_byte) {
1404 block_group = btrfs_lookup_block_group(info, hint_byte);
1405 if (!block_group)
1406 hint_byte = search_start;
1407 block_group = btrfs_find_block_group(root, block_group,
1408 hint_byte, data, 1);
1409 } else {
1410 block_group = btrfs_find_block_group(root,
1411 trans->block_group,
1412 search_start, data, 1);
1413 }
1414
1415 total_needed += empty_size;
1416 path = btrfs_alloc_path();
1417 check_failed:
1418 if (!block_group) {
1419 block_group = btrfs_lookup_block_group(info, search_start);
1420 if (!block_group)
1421 block_group = btrfs_lookup_block_group(info,
1422 orig_search_start);
1423 }
1424 search_start = find_search_start(root, &block_group, search_start,
1425 total_needed, data, full_scan);
1426 search_start = stripe_align(root, search_start);
1427 cached_start = search_start;
1428 btrfs_init_path(path);
1429 ins->objectid = search_start;
1430 ins->offset = 0;
1431 start_found = 0;
1432 path->reada = 2;
1433
1434 ret = btrfs_search_slot(trans, root, ins, path, 0, 0);
1435 if (ret < 0)
1436 goto error;
1437
1438 if (path->slots[0] > 0) {
1439 path->slots[0]--;
1440 }
1441
1442 l = path->nodes[0];
1443 btrfs_item_key_to_cpu(l, &key, path->slots[0]);
1444
1445 /*
1446 * walk backwards to find the first extent item key
1447 */
1448 while(btrfs_key_type(&key) != BTRFS_EXTENT_ITEM_KEY) {
1449 if (path->slots[0] == 0) {
1450 ret = btrfs_prev_leaf(root, path);
1451 if (ret != 0) {
1452 ret = btrfs_search_slot(trans, root, ins,
1453 path, 0, 0);
1454 if (ret < 0)
1455 goto error;
1456 if (path->slots[0] > 0)
1457 path->slots[0]--;
1458 break;
1459 }
1460 } else {
1461 path->slots[0]--;
1462 }
1463 l = path->nodes[0];
1464 btrfs_item_key_to_cpu(l, &key, path->slots[0]);
1465 }
1466 while (1) {
1467 l = path->nodes[0];
1468 slot = path->slots[0];
1469 if (slot >= btrfs_header_nritems(l)) {
1470 ret = btrfs_next_leaf(root, path);
1471 if (ret == 0)
1472 continue;
1473 if (ret < 0)
1474 goto error;
1475
1476 search_start = max(search_start,
1477 block_group->key.objectid);
1478 if (!start_found) {
1479 aligned = stripe_align(root, search_start);
1480 ins->objectid = aligned;
1481 if (aligned >= search_end) {
1482 ret = -ENOSPC;
1483 goto error;
1484 }
1485 ins->offset = search_end - aligned;
1486 start_found = 1;
1487 goto check_pending;
1488 }
1489 ins->objectid = stripe_align(root,
1490 last_byte > search_start ?
1491 last_byte : search_start);
1492 if (search_end <= ins->objectid) {
1493 ret = -ENOSPC;
1494 goto error;
1495 }
1496 ins->offset = search_end - ins->objectid;
1497 BUG_ON(ins->objectid >= search_end);
1498 goto check_pending;
1499 }
1500 btrfs_item_key_to_cpu(l, &key, slot);
1501
1502 if (key.objectid >= search_start && key.objectid > last_byte &&
1503 start_found) {
1504 if (last_byte < search_start)
1505 last_byte = search_start;
1506 aligned = stripe_align(root, last_byte);
1507 hole_size = key.objectid - aligned;
1508 if (key.objectid > aligned && hole_size >= num_bytes) {
1509 ins->objectid = aligned;
1510 ins->offset = hole_size;
1511 goto check_pending;
1512 }
1513 }
1514 if (btrfs_key_type(&key) != BTRFS_EXTENT_ITEM_KEY) {
1515 if (!start_found && btrfs_key_type(&key) ==
1516 BTRFS_BLOCK_GROUP_ITEM_KEY) {
1517 last_byte = key.objectid;
1518 start_found = 1;
1519 }
1520 goto next;
1521 }
1522
1523
1524 start_found = 1;
1525 last_byte = key.objectid + key.offset;
1526
1527 if (!full_scan && data != BTRFS_BLOCK_GROUP_MIXED &&
1528 last_byte >= block_group->key.objectid +
1529 block_group->key.offset) {
1530 btrfs_release_path(root, path);
1531 search_start = block_group->key.objectid +
1532 block_group->key.offset;
1533 goto new_group;
1534 }
1535 next:
1536 path->slots[0]++;
1537 cond_resched();
1538 }
1539 check_pending:
1540 /* we have to make sure we didn't find an extent that has already
1541 * been allocated by the map tree or the original allocation
1542 */
1543 btrfs_release_path(root, path);
1544 BUG_ON(ins->objectid < search_start);
1545
1546 if (ins->objectid + num_bytes >= search_end)
1547 goto enospc;
1548 if (!full_scan && data != BTRFS_BLOCK_GROUP_MIXED &&
1549 ins->objectid + num_bytes > block_group->
1550 key.objectid + block_group->key.offset) {
1551 search_start = block_group->key.objectid +
1552 block_group->key.offset;
1553 goto new_group;
1554 }
1555 if (test_range_bit(&info->extent_ins, ins->objectid,
1556 ins->objectid + num_bytes -1, EXTENT_LOCKED, 0)) {
1557 search_start = ins->objectid + num_bytes;
1558 goto new_group;
1559 }
1560 if (test_range_bit(&info->pinned_extents, ins->objectid,
1561 ins->objectid + num_bytes -1, EXTENT_DIRTY, 0)) {
1562 search_start = ins->objectid + num_bytes;
1563 goto new_group;
1564 }
1565 if (exclude_nr > 0 && (ins->objectid + num_bytes > exclude_start &&
1566 ins->objectid < exclude_start + exclude_nr)) {
1567 search_start = exclude_start + exclude_nr;
1568 goto new_group;
1569 }
1570 if (!data) {
1571 block_group = btrfs_lookup_block_group(info, ins->objectid);
1572 if (block_group)
1573 trans->block_group = block_group;
1574 }
1575 ins->offset = num_bytes;
1576 btrfs_free_path(path);
1577 return 0;
1578
1579 new_group:
1580 if (search_start + num_bytes >= search_end) {
1581 enospc:
1582 search_start = orig_search_start;
1583 if (full_scan) {
1584 ret = -ENOSPC;
1585 goto error;
1586 }
1587 if (wrapped) {
1588 if (!full_scan)
1589 total_needed -= empty_size;
1590 full_scan = 1;
1591 data = BTRFS_BLOCK_GROUP_MIXED;
1592 } else
1593 wrapped = 1;
1594 }
1595 block_group = btrfs_lookup_block_group(info, search_start);
1596 cond_resched();
1597 block_group = btrfs_find_block_group(root, block_group,
1598 search_start, data, 0);
1599 goto check_failed;
1600
1601 error:
1602 btrfs_release_path(root, path);
1603 btrfs_free_path(path);
1604 return ret;
1605 }
1606 /*
1607 * finds a free extent and does all the dirty work required for allocation
1608 * returns the key for the extent through ins, and a tree buffer for
1609 * the first block of the extent through buf.
1610 *
1611 * returns 0 if everything worked, non-zero otherwise.
1612 */
1613 int btrfs_alloc_extent(struct btrfs_trans_handle *trans,
1614 struct btrfs_root *root,
1615 u64 num_bytes, u64 root_objectid, u64 ref_generation,
1616 u64 owner, u64 owner_offset,
1617 u64 empty_size, u64 hint_byte,
1618 u64 search_end, struct btrfs_key *ins, int data)
1619 {
1620 int ret;
1621 int pending_ret;
1622 u64 super_used, root_used;
1623 u64 search_start = 0;
1624 u64 new_hint;
1625 struct btrfs_fs_info *info = root->fs_info;
1626 struct btrfs_root *extent_root = info->extent_root;
1627 struct btrfs_extent_item extent_item;
1628 struct btrfs_path *path;
1629
1630 btrfs_set_stack_extent_refs(&extent_item, 1);
1631
1632 new_hint = max(hint_byte, root->fs_info->alloc_start);
1633 if (new_hint < btrfs_super_total_bytes(&info->super_copy))
1634 hint_byte = new_hint;
1635
1636 WARN_ON(num_bytes < root->sectorsize);
1637 ret = find_free_extent(trans, root, num_bytes, empty_size,
1638 search_start, search_end, hint_byte, ins,
1639 trans->alloc_exclude_start,
1640 trans->alloc_exclude_nr, data);
1641 BUG_ON(ret);
1642 if (ret)
1643 return ret;
1644
1645 /* block accounting for super block */
1646 super_used = btrfs_super_bytes_used(&info->super_copy);
1647 btrfs_set_super_bytes_used(&info->super_copy, super_used + num_bytes);
1648
1649 /* block accounting for root item */
1650 root_used = btrfs_root_used(&root->root_item);
1651 btrfs_set_root_used(&root->root_item, root_used + num_bytes);
1652
1653 clear_extent_dirty(&root->fs_info->free_space_cache,
1654 ins->objectid, ins->objectid + ins->offset - 1,
1655 GFP_NOFS);
1656
1657 if (root == extent_root) {
1658 set_extent_bits(&root->fs_info->extent_ins, ins->objectid,
1659 ins->objectid + ins->offset - 1,
1660 EXTENT_LOCKED, GFP_NOFS);
1661 WARN_ON(data == 1);
1662 goto update_block;
1663 }
1664
1665 WARN_ON(trans->alloc_exclude_nr);
1666 trans->alloc_exclude_start = ins->objectid;
1667 trans->alloc_exclude_nr = ins->offset;
1668 ret = btrfs_insert_item(trans, extent_root, ins, &extent_item,
1669 sizeof(extent_item));
1670
1671 trans->alloc_exclude_start = 0;
1672 trans->alloc_exclude_nr = 0;
1673 BUG_ON(ret);
1674
1675 path = btrfs_alloc_path();
1676 BUG_ON(!path);
1677 ret = btrfs_insert_extent_backref(trans, extent_root, path,
1678 ins->objectid, root_objectid,
1679 ref_generation, owner, owner_offset);
1680
1681 BUG_ON(ret);
1682 btrfs_free_path(path);
1683 finish_current_insert(trans, extent_root);
1684 pending_ret = del_pending_extents(trans, extent_root);
1685
1686 if (ret) {
1687 return ret;
1688 }
1689 if (pending_ret) {
1690 return pending_ret;
1691 }
1692
1693 update_block:
1694 ret = update_block_group(trans, root, ins->objectid, ins->offset, 1, 0,
1695 data);
1696 BUG_ON(ret);
1697 return 0;
1698 }
1699
1700 /*
1701 * helper function to allocate a block for a given tree
1702 * returns the tree buffer or NULL.
1703 */
1704 struct extent_buffer *btrfs_alloc_free_block(struct btrfs_trans_handle *trans,
1705 struct btrfs_root *root,
1706 u32 blocksize,
1707 u64 root_objectid, u64 hint,
1708 u64 empty_size)
1709 {
1710 u64 ref_generation;
1711
1712 if (root->ref_cows)
1713 ref_generation = trans->transid;
1714 else
1715 ref_generation = 0;
1716
1717
1718 return __btrfs_alloc_free_block(trans, root, blocksize, root_objectid,
1719 ref_generation, 0, 0, hint, empty_size);
1720 }
1721
1722 /*
1723 * helper function to allocate a block for a given tree
1724 * returns the tree buffer or NULL.
1725 */
1726 struct extent_buffer *__btrfs_alloc_free_block(struct btrfs_trans_handle *trans,
1727 struct btrfs_root *root,
1728 u32 blocksize,
1729 u64 root_objectid,
1730 u64 ref_generation,
1731 u64 first_objectid,
1732 int level,
1733 u64 hint,
1734 u64 empty_size)
1735 {
1736 struct btrfs_key ins;
1737 int ret;
1738 struct extent_buffer *buf;
1739
1740 ret = btrfs_alloc_extent(trans, root, blocksize,
1741 root_objectid, ref_generation,
1742 level, first_objectid, empty_size, hint,
1743 (u64)-1, &ins, 0);
1744 if (ret) {
1745 BUG_ON(ret > 0);
1746 return ERR_PTR(ret);
1747 }
1748 buf = btrfs_find_create_tree_block(root, ins.objectid, blocksize);
1749 if (!buf) {
1750 btrfs_free_extent(trans, root, ins.objectid, blocksize,
1751 root->root_key.objectid, ref_generation,
1752 0, 0, 0);
1753 return ERR_PTR(-ENOMEM);
1754 }
1755 btrfs_set_buffer_uptodate(buf);
1756 set_extent_dirty(&trans->transaction->dirty_pages, buf->start,
1757 buf->start + buf->len - 1, GFP_NOFS);
1758 set_extent_bits(&BTRFS_I(root->fs_info->btree_inode)->extent_tree,
1759 buf->start, buf->start + buf->len - 1,
1760 EXTENT_CSUM, GFP_NOFS);
1761 buf->flags |= EXTENT_CSUM;
1762 btrfs_set_buffer_defrag(buf);
1763 trans->blocks_used++;
1764 return buf;
1765 }
1766
1767 static int noinline drop_leaf_ref(struct btrfs_trans_handle *trans,
1768 struct btrfs_root *root,
1769 struct extent_buffer *leaf)
1770 {
1771 u64 leaf_owner;
1772 u64 leaf_generation;
1773 struct btrfs_key key;
1774 struct btrfs_file_extent_item *fi;
1775 int i;
1776 int nritems;
1777 int ret;
1778
1779 BUG_ON(!btrfs_is_leaf(leaf));
1780 nritems = btrfs_header_nritems(leaf);
1781 leaf_owner = btrfs_header_owner(leaf);
1782 leaf_generation = btrfs_header_generation(leaf);
1783
1784 for (i = 0; i < nritems; i++) {
1785 u64 disk_bytenr;
1786
1787 btrfs_item_key_to_cpu(leaf, &key, i);
1788 if (btrfs_key_type(&key) != BTRFS_EXTENT_DATA_KEY)
1789 continue;
1790 fi = btrfs_item_ptr(leaf, i, struct btrfs_file_extent_item);
1791 if (btrfs_file_extent_type(leaf, fi) ==
1792 BTRFS_FILE_EXTENT_INLINE)
1793 continue;
1794 /*
1795 * FIXME make sure to insert a trans record that
1796 * repeats the snapshot del on crash
1797 */
1798 disk_bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
1799 if (disk_bytenr == 0)
1800 continue;
1801 ret = btrfs_free_extent(trans, root, disk_bytenr,
1802 btrfs_file_extent_disk_num_bytes(leaf, fi),
1803 leaf_owner, leaf_generation,
1804 key.objectid, key.offset, 0);
1805 BUG_ON(ret);
1806 }
1807 return 0;
1808 }
1809
1810 static void noinline reada_walk_down(struct btrfs_root *root,
1811 struct extent_buffer *node)
1812 {
1813 int i;
1814 u32 nritems;
1815 u64 bytenr;
1816 int ret;
1817 u32 refs;
1818 int level;
1819 u32 blocksize;
1820
1821 nritems = btrfs_header_nritems(node);
1822 level = btrfs_header_level(node);
1823 for (i = 0; i < nritems; i++) {
1824 bytenr = btrfs_node_blockptr(node, i);
1825 blocksize = btrfs_level_size(root, level - 1);
1826 ret = lookup_extent_ref(NULL, root, bytenr, blocksize, &refs);
1827 BUG_ON(ret);
1828 if (refs != 1)
1829 continue;
1830 mutex_unlock(&root->fs_info->fs_mutex);
1831 ret = readahead_tree_block(root, bytenr, blocksize);
1832 cond_resched();
1833 mutex_lock(&root->fs_info->fs_mutex);
1834 if (ret)
1835 break;
1836 }
1837 }
1838
1839 /*
1840 * helper function for drop_snapshot, this walks down the tree dropping ref
1841 * counts as it goes.
1842 */
1843 static int noinline walk_down_tree(struct btrfs_trans_handle *trans,
1844 struct btrfs_root *root,
1845 struct btrfs_path *path, int *level)
1846 {
1847 u64 root_owner;
1848 u64 root_gen;
1849 u64 bytenr;
1850 struct extent_buffer *next;
1851 struct extent_buffer *cur;
1852 struct extent_buffer *parent;
1853 u32 blocksize;
1854 int ret;
1855 u32 refs;
1856
1857 WARN_ON(*level < 0);
1858 WARN_ON(*level >= BTRFS_MAX_LEVEL);
1859 ret = lookup_extent_ref(trans, root,
1860 path->nodes[*level]->start,
1861 path->nodes[*level]->len, &refs);
1862 BUG_ON(ret);
1863 if (refs > 1)
1864 goto out;
1865
1866 /*
1867 * walk down to the last node level and free all the leaves
1868 */
1869 while(*level >= 0) {
1870 WARN_ON(*level < 0);
1871 WARN_ON(*level >= BTRFS_MAX_LEVEL);
1872 cur = path->nodes[*level];
1873
1874 if (*level > 0 && path->slots[*level] == 0)
1875 reada_walk_down(root, cur);
1876
1877 if (btrfs_header_level(cur) != *level)
1878 WARN_ON(1);
1879
1880 if (path->slots[*level] >=
1881 btrfs_header_nritems(cur))
1882 break;
1883 if (*level == 0) {
1884 ret = drop_leaf_ref(trans, root, cur);
1885 BUG_ON(ret);
1886 break;
1887 }
1888 bytenr = btrfs_node_blockptr(cur, path->slots[*level]);
1889 blocksize = btrfs_level_size(root, *level - 1);
1890 ret = lookup_extent_ref(trans, root, bytenr, blocksize, &refs);
1891 BUG_ON(ret);
1892 if (refs != 1) {
1893 parent = path->nodes[*level];
1894 root_owner = btrfs_header_owner(parent);
1895 root_gen = btrfs_header_generation(parent);
1896 path->slots[*level]++;
1897 ret = btrfs_free_extent(trans, root, bytenr,
1898 blocksize, root_owner,
1899 root_gen, 0, 0, 1);
1900 BUG_ON(ret);
1901 continue;
1902 }
1903 next = btrfs_find_tree_block(root, bytenr, blocksize);
1904 if (!next || !btrfs_buffer_uptodate(next)) {
1905 free_extent_buffer(next);
1906 mutex_unlock(&root->fs_info->fs_mutex);
1907 next = read_tree_block(root, bytenr, blocksize);
1908 mutex_lock(&root->fs_info->fs_mutex);
1909
1910 /* we dropped the lock, check one more time */
1911 ret = lookup_extent_ref(trans, root, bytenr,
1912 blocksize, &refs);
1913 BUG_ON(ret);
1914 if (refs != 1) {
1915 parent = path->nodes[*level];
1916 root_owner = btrfs_header_owner(parent);
1917 root_gen = btrfs_header_generation(parent);
1918
1919 path->slots[*level]++;
1920 free_extent_buffer(next);
1921 ret = btrfs_free_extent(trans, root, bytenr,
1922 blocksize,
1923 root_owner,
1924 root_gen, 0, 0, 1);
1925 BUG_ON(ret);
1926 continue;
1927 }
1928 }
1929 WARN_ON(*level <= 0);
1930 if (path->nodes[*level-1])
1931 free_extent_buffer(path->nodes[*level-1]);
1932 path->nodes[*level-1] = next;
1933 *level = btrfs_header_level(next);
1934 path->slots[*level] = 0;
1935 }
1936 out:
1937 WARN_ON(*level < 0);
1938 WARN_ON(*level >= BTRFS_MAX_LEVEL);
1939
1940 if (path->nodes[*level] == root->node) {
1941 root_owner = root->root_key.objectid;
1942 parent = path->nodes[*level];
1943 } else {
1944 parent = path->nodes[*level + 1];
1945 root_owner = btrfs_header_owner(parent);
1946 }
1947
1948 root_gen = btrfs_header_generation(parent);
1949 ret = btrfs_free_extent(trans, root, path->nodes[*level]->start,
1950 path->nodes[*level]->len,
1951 root_owner, root_gen, 0, 0, 1);
1952 free_extent_buffer(path->nodes[*level]);
1953 path->nodes[*level] = NULL;
1954 *level += 1;
1955 BUG_ON(ret);
1956 return 0;
1957 }
1958
1959 /*
1960 * helper for dropping snapshots. This walks back up the tree in the path
1961 * to find the first node higher up where we haven't yet gone through
1962 * all the slots
1963 */
1964 static int noinline walk_up_tree(struct btrfs_trans_handle *trans,
1965 struct btrfs_root *root,
1966 struct btrfs_path *path, int *level)
1967 {
1968 u64 root_owner;
1969 u64 root_gen;
1970 struct btrfs_root_item *root_item = &root->root_item;
1971 int i;
1972 int slot;
1973 int ret;
1974
1975 for(i = *level; i < BTRFS_MAX_LEVEL - 1 && path->nodes[i]; i++) {
1976 slot = path->slots[i];
1977 if (slot < btrfs_header_nritems(path->nodes[i]) - 1) {
1978 struct extent_buffer *node;
1979 struct btrfs_disk_key disk_key;
1980 node = path->nodes[i];
1981 path->slots[i]++;
1982 *level = i;
1983 WARN_ON(*level == 0);
1984 btrfs_node_key(node, &disk_key, path->slots[i]);
1985 memcpy(&root_item->drop_progress,
1986 &disk_key, sizeof(disk_key));
1987 root_item->drop_level = i;
1988 return 0;
1989 } else {
1990 if (path->nodes[*level] == root->node) {
1991 root_owner = root->root_key.objectid;
1992 root_gen =
1993 btrfs_header_generation(path->nodes[*level]);
1994 } else {
1995 struct extent_buffer *node;
1996 node = path->nodes[*level + 1];
1997 root_owner = btrfs_header_owner(node);
1998 root_gen = btrfs_header_generation(node);
1999 }
2000 ret = btrfs_free_extent(trans, root,
2001 path->nodes[*level]->start,
2002 path->nodes[*level]->len,
2003 root_owner, root_gen, 0, 0, 1);
2004 BUG_ON(ret);
2005 free_extent_buffer(path->nodes[*level]);
2006 path->nodes[*level] = NULL;
2007 *level = i + 1;
2008 }
2009 }
2010 return 1;
2011 }
2012
2013 /*
2014 * drop the reference count on the tree rooted at 'snap'. This traverses
2015 * the tree freeing any blocks that have a ref count of zero after being
2016 * decremented.
2017 */
2018 int btrfs_drop_snapshot(struct btrfs_trans_handle *trans, struct btrfs_root
2019 *root)
2020 {
2021 int ret = 0;
2022 int wret;
2023 int level;
2024 struct btrfs_path *path;
2025 int i;
2026 int orig_level;
2027 struct btrfs_root_item *root_item = &root->root_item;
2028
2029 path = btrfs_alloc_path();
2030 BUG_ON(!path);
2031
2032 level = btrfs_header_level(root->node);
2033 orig_level = level;
2034 if (btrfs_disk_key_objectid(&root_item->drop_progress) == 0) {
2035 path->nodes[level] = root->node;
2036 extent_buffer_get(root->node);
2037 path->slots[level] = 0;
2038 } else {
2039 struct btrfs_key key;
2040 struct btrfs_disk_key found_key;
2041 struct extent_buffer *node;
2042
2043 btrfs_disk_key_to_cpu(&key, &root_item->drop_progress);
2044 level = root_item->drop_level;
2045 path->lowest_level = level;
2046 wret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
2047 if (wret < 0) {
2048 ret = wret;
2049 goto out;
2050 }
2051 node = path->nodes[level];
2052 btrfs_node_key(node, &found_key, path->slots[level]);
2053 WARN_ON(memcmp(&found_key, &root_item->drop_progress,
2054 sizeof(found_key)));
2055 }
2056 while(1) {
2057 wret = walk_down_tree(trans, root, path, &level);
2058 if (wret > 0)
2059 break;
2060 if (wret < 0)
2061 ret = wret;
2062
2063 wret = walk_up_tree(trans, root, path, &level);
2064 if (wret > 0)
2065 break;
2066 if (wret < 0)
2067 ret = wret;
2068 ret = -EAGAIN;
2069 break;
2070 }
2071 for (i = 0; i <= orig_level; i++) {
2072 if (path->nodes[i]) {
2073 free_extent_buffer(path->nodes[i]);
2074 path->nodes[i] = NULL;
2075 }
2076 }
2077 out:
2078 btrfs_free_path(path);
2079 return ret;
2080 }
2081
2082 int btrfs_free_block_groups(struct btrfs_fs_info *info)
2083 {
2084 u64 start;
2085 u64 end;
2086 u64 ptr;
2087 int ret;
2088 while(1) {
2089 ret = find_first_extent_bit(&info->block_group_cache, 0,
2090 &start, &end, (unsigned int)-1);
2091 if (ret)
2092 break;
2093 ret = get_state_private(&info->block_group_cache, start, &ptr);
2094 if (!ret)
2095 kfree((void *)(unsigned long)ptr);
2096 clear_extent_bits(&info->block_group_cache, start,
2097 end, (unsigned int)-1, GFP_NOFS);
2098 }
2099 while(1) {
2100 ret = find_first_extent_bit(&info->free_space_cache, 0,
2101 &start, &end, EXTENT_DIRTY);
2102 if (ret)
2103 break;
2104 clear_extent_dirty(&info->free_space_cache, start,
2105 end, GFP_NOFS);
2106 }
2107 return 0;
2108 }
2109
2110 static int noinline relocate_inode_pages(struct inode *inode, u64 start,
2111 u64 len)
2112 {
2113 u64 page_start;
2114 u64 page_end;
2115 u64 delalloc_start;
2116 u64 existing_delalloc;
2117 unsigned long last_index;
2118 unsigned long i;
2119 struct page *page;
2120 struct btrfs_root *root = BTRFS_I(inode)->root;
2121 struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
2122 struct file_ra_state *ra;
2123
2124 ra = kzalloc(sizeof(*ra), GFP_NOFS);
2125
2126 mutex_lock(&inode->i_mutex);
2127 i = start >> PAGE_CACHE_SHIFT;
2128 last_index = (start + len - 1) >> PAGE_CACHE_SHIFT;
2129
2130 file_ra_state_init(ra, inode->i_mapping);
2131 btrfs_force_ra(inode->i_mapping, ra, NULL, i, last_index);
2132 kfree(ra);
2133
2134 for (; i <= last_index; i++) {
2135 page = grab_cache_page(inode->i_mapping, i);
2136 if (!page)
2137 goto out_unlock;
2138 if (!PageUptodate(page)) {
2139 btrfs_readpage(NULL, page);
2140 lock_page(page);
2141 if (!PageUptodate(page)) {
2142 unlock_page(page);
2143 page_cache_release(page);
2144 goto out_unlock;
2145 }
2146 }
2147 page_start = (u64)page->index << PAGE_CACHE_SHIFT;
2148 page_end = page_start + PAGE_CACHE_SIZE - 1;
2149
2150 lock_extent(em_tree, page_start, page_end, GFP_NOFS);
2151
2152 delalloc_start = page_start;
2153 existing_delalloc =
2154 count_range_bits(&BTRFS_I(inode)->extent_tree,
2155 &delalloc_start, page_end,
2156 PAGE_CACHE_SIZE, EXTENT_DELALLOC);
2157
2158 set_extent_delalloc(em_tree, page_start,
2159 page_end, GFP_NOFS);
2160
2161 spin_lock(&root->fs_info->delalloc_lock);
2162 root->fs_info->delalloc_bytes += PAGE_CACHE_SIZE -
2163 existing_delalloc;
2164 spin_unlock(&root->fs_info->delalloc_lock);
2165
2166 unlock_extent(em_tree, page_start, page_end, GFP_NOFS);
2167 set_page_dirty(page);
2168 unlock_page(page);
2169 page_cache_release(page);
2170 }
2171
2172 out_unlock:
2173 mutex_unlock(&inode->i_mutex);
2174 return 0;
2175 }
2176
2177 /*
2178 * note, this releases the path
2179 */
2180 static int noinline relocate_one_reference(struct btrfs_root *extent_root,
2181 struct btrfs_path *path,
2182 struct btrfs_key *extent_key)
2183 {
2184 struct inode *inode;
2185 struct btrfs_root *found_root;
2186 struct btrfs_key *root_location;
2187 struct btrfs_extent_ref *ref;
2188 u64 ref_root;
2189 u64 ref_gen;
2190 u64 ref_objectid;
2191 u64 ref_offset;
2192 int ret;
2193
2194 ref = btrfs_item_ptr(path->nodes[0], path->slots[0],
2195 struct btrfs_extent_ref);
2196 ref_root = btrfs_ref_root(path->nodes[0], ref);
2197 ref_gen = btrfs_ref_generation(path->nodes[0], ref);
2198 ref_objectid = btrfs_ref_objectid(path->nodes[0], ref);
2199 ref_offset = btrfs_ref_offset(path->nodes[0], ref);
2200 btrfs_release_path(extent_root, path);
2201
2202 root_location = kmalloc(sizeof(*root_location), GFP_NOFS);
2203 root_location->objectid = ref_root;
2204 if (ref_gen == 0)
2205 root_location->offset = 0;
2206 else
2207 root_location->offset = (u64)-1;
2208 root_location->type = BTRFS_ROOT_ITEM_KEY;
2209
2210 found_root = btrfs_read_fs_root_no_name(extent_root->fs_info,
2211 root_location);
2212 BUG_ON(!found_root);
2213 kfree(root_location);
2214
2215 if (ref_objectid >= BTRFS_FIRST_FREE_OBJECTID) {
2216 mutex_unlock(&extent_root->fs_info->fs_mutex);
2217 inode = btrfs_iget_locked(extent_root->fs_info->sb,
2218 ref_objectid, found_root);
2219 if (inode->i_state & I_NEW) {
2220 /* the inode and parent dir are two different roots */
2221 BTRFS_I(inode)->root = found_root;
2222 BTRFS_I(inode)->location.objectid = ref_objectid;
2223 BTRFS_I(inode)->location.type = BTRFS_INODE_ITEM_KEY;
2224 BTRFS_I(inode)->location.offset = 0;
2225 btrfs_read_locked_inode(inode);
2226 unlock_new_inode(inode);
2227
2228 }
2229 /* this can happen if the reference is not against
2230 * the latest version of the tree root
2231 */
2232 if (is_bad_inode(inode)) {
2233 mutex_lock(&extent_root->fs_info->fs_mutex);
2234 goto out;
2235 }
2236 relocate_inode_pages(inode, ref_offset, extent_key->offset);
2237 /* FIXME, data=ordered will help get rid of this */
2238 filemap_fdatawrite(inode->i_mapping);
2239 iput(inode);
2240 mutex_lock(&extent_root->fs_info->fs_mutex);
2241 } else {
2242 struct btrfs_trans_handle *trans;
2243 struct btrfs_key found_key;
2244 struct extent_buffer *eb;
2245 int level;
2246 int i;
2247
2248 trans = btrfs_start_transaction(found_root, 1);
2249 eb = read_tree_block(found_root, extent_key->objectid,
2250 extent_key->offset);
2251 level = btrfs_header_level(eb);
2252
2253 if (level == 0)
2254 btrfs_item_key_to_cpu(eb, &found_key, 0);
2255 else
2256 btrfs_node_key_to_cpu(eb, &found_key, 0);
2257
2258 free_extent_buffer(eb);
2259
2260 path->lowest_level = level;
2261 path->reada = 2;
2262 ret = btrfs_search_slot(trans, found_root, &found_key, path,
2263 0, 1);
2264 path->lowest_level = 0;
2265 for (i = level; i < BTRFS_MAX_LEVEL; i++) {
2266 if (!path->nodes[i])
2267 break;
2268 free_extent_buffer(path->nodes[i]);
2269 path->nodes[i] = NULL;
2270 }
2271 btrfs_release_path(found_root, path);
2272 btrfs_end_transaction(trans, found_root);
2273 }
2274
2275 out:
2276 return 0;
2277 }
2278
2279 static int noinline relocate_one_extent(struct btrfs_root *extent_root,
2280 struct btrfs_path *path,
2281 struct btrfs_key *extent_key)
2282 {
2283 struct btrfs_key key;
2284 struct btrfs_key found_key;
2285 struct extent_buffer *leaf;
2286 u32 nritems;
2287 u32 item_size;
2288 int ret = 0;
2289
2290 key.objectid = extent_key->objectid;
2291 key.type = BTRFS_EXTENT_REF_KEY;
2292 key.offset = 0;
2293
2294 while(1) {
2295 ret = btrfs_search_slot(NULL, extent_root, &key, path, 0, 0);
2296
2297 BUG_ON(ret == 0);
2298
2299 if (ret < 0)
2300 goto out;
2301
2302 ret = 0;
2303 leaf = path->nodes[0];
2304 nritems = btrfs_header_nritems(leaf);
2305 if (path->slots[0] == nritems)
2306 goto out;
2307
2308 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
2309 if (found_key.objectid != extent_key->objectid)
2310 break;
2311
2312 if (found_key.type != BTRFS_EXTENT_REF_KEY)
2313 break;
2314
2315 key.offset = found_key.offset + 1;
2316 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
2317
2318 ret = relocate_one_reference(extent_root, path, extent_key);
2319 if (ret)
2320 goto out;
2321 }
2322 ret = 0;
2323 out:
2324 btrfs_release_path(extent_root, path);
2325 return ret;
2326 }
2327
2328 static int find_overlapping_extent(struct btrfs_root *root,
2329 struct btrfs_path *path, u64 new_size)
2330 {
2331 struct btrfs_key found_key;
2332 struct extent_buffer *leaf;
2333 int ret;
2334
2335 while(1) {
2336 if (path->slots[0] == 0) {
2337 ret = btrfs_prev_leaf(root, path);
2338 if (ret == 1) {
2339 return 1;
2340 }
2341 if (ret < 0)
2342 return ret;
2343 } else {
2344 path->slots[0]--;
2345 }
2346 leaf = path->nodes[0];
2347 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
2348 if (found_key.type == BTRFS_EXTENT_ITEM_KEY) {
2349 if (found_key.objectid + found_key.offset > new_size)
2350 return 0;
2351 else
2352 return 1;
2353 }
2354 }
2355 return 1;
2356 }
2357
2358 int btrfs_shrink_extent_tree(struct btrfs_root *root, u64 new_size)
2359 {
2360 struct btrfs_trans_handle *trans;
2361 struct btrfs_root *tree_root = root->fs_info->tree_root;
2362 struct btrfs_path *path;
2363 u64 cur_byte;
2364 u64 total_found;
2365 struct btrfs_fs_info *info = root->fs_info;
2366 struct extent_map_tree *block_group_cache;
2367 struct btrfs_key key;
2368 struct btrfs_key found_key = { 0, 0, 0 };
2369 struct extent_buffer *leaf;
2370 u32 nritems;
2371 int ret;
2372 int slot;
2373
2374 btrfs_set_super_total_bytes(&info->super_copy, new_size);
2375 block_group_cache = &info->block_group_cache;
2376 path = btrfs_alloc_path();
2377 root = root->fs_info->extent_root;
2378 path->reada = 2;
2379
2380 again:
2381 total_found = 0;
2382 key.objectid = new_size;
2383 cur_byte = key.objectid;
2384 key.offset = 0;
2385 key.type = 0;
2386 while(1) {
2387
2388 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
2389 if (ret < 0)
2390 goto out;
2391 next:
2392 leaf = path->nodes[0];
2393 if (key.objectid == new_size - 1) {
2394 ret = find_overlapping_extent(root, path, new_size);
2395 if (ret != 0) {
2396 btrfs_release_path(root, path);
2397 ret = btrfs_search_slot(NULL, root, &key,
2398 path, 0, 0);
2399 if (ret < 0)
2400 goto out;
2401 }
2402 }
2403 nritems = btrfs_header_nritems(leaf);
2404 ret = 0;
2405 slot = path->slots[0];
2406 if (slot < nritems)
2407 btrfs_item_key_to_cpu(leaf, &found_key, slot);
2408 if (slot == nritems ||
2409 btrfs_key_type(&found_key) != BTRFS_EXTENT_ITEM_KEY) {
2410 path->slots[0]++;
2411 if (path->slots[0] >= nritems) {
2412 ret = btrfs_next_leaf(root, path);
2413 if (ret < 0)
2414 goto out;
2415 if (ret == 1) {
2416 ret = 0;
2417 break;
2418 }
2419 }
2420 goto next;
2421 }
2422 btrfs_item_key_to_cpu(leaf, &found_key, slot);
2423 if (found_key.objectid + found_key.offset <= cur_byte)
2424 continue;
2425 total_found++;
2426 cur_byte = found_key.objectid + found_key.offset;
2427 key.objectid = cur_byte;
2428 btrfs_release_path(root, path);
2429 ret = relocate_one_extent(root, path, &found_key);
2430 }
2431
2432 btrfs_release_path(root, path);
2433
2434 if (total_found > 0) {
2435 trans = btrfs_start_transaction(tree_root, 1);
2436 btrfs_commit_transaction(trans, tree_root);
2437
2438 mutex_unlock(&root->fs_info->fs_mutex);
2439 btrfs_clean_old_snapshots(tree_root);
2440 mutex_lock(&root->fs_info->fs_mutex);
2441
2442 trans = btrfs_start_transaction(tree_root, 1);
2443 btrfs_commit_transaction(trans, tree_root);
2444 goto again;
2445 }
2446
2447 trans = btrfs_start_transaction(root, 1);
2448 key.objectid = new_size;
2449 key.offset = 0;
2450 key.type = 0;
2451 while(1) {
2452 u64 ptr;
2453
2454 ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
2455 if (ret < 0)
2456 goto out;
2457 bg_next:
2458 leaf = path->nodes[0];
2459 nritems = btrfs_header_nritems(leaf);
2460 ret = 0;
2461 slot = path->slots[0];
2462 if (slot < nritems)
2463 btrfs_item_key_to_cpu(leaf, &found_key, slot);
2464 if (slot == nritems ||
2465 btrfs_key_type(&found_key) != BTRFS_BLOCK_GROUP_ITEM_KEY) {
2466 if (slot < nritems) {
2467 printk("shrinker found key %Lu %u %Lu\n",
2468 found_key.objectid, found_key.type,
2469 found_key.offset);
2470 path->slots[0]++;
2471 }
2472 if (path->slots[0] >= nritems) {
2473 ret = btrfs_next_leaf(root, path);
2474 if (ret < 0)
2475 break;
2476 if (ret == 1) {
2477 ret = 0;
2478 break;
2479 }
2480 }
2481 goto bg_next;
2482 }
2483 btrfs_item_key_to_cpu(leaf, &found_key, slot);
2484 ret = get_state_private(&info->block_group_cache,
2485 found_key.objectid, &ptr);
2486 if (!ret)
2487 kfree((void *)(unsigned long)ptr);
2488
2489 clear_extent_bits(&info->block_group_cache, found_key.objectid,
2490 found_key.objectid + found_key.offset - 1,
2491 (unsigned int)-1, GFP_NOFS);
2492
2493 key.objectid = found_key.objectid + 1;
2494 btrfs_del_item(trans, root, path);
2495 btrfs_release_path(root, path);
2496 }
2497 clear_extent_dirty(&info->free_space_cache, new_size, (u64)-1,
2498 GFP_NOFS);
2499 btrfs_commit_transaction(trans, root);
2500 out:
2501 btrfs_free_path(path);
2502 return ret;
2503 }
2504
2505 int btrfs_grow_extent_tree(struct btrfs_trans_handle *trans,
2506 struct btrfs_root *root, u64 new_size)
2507 {
2508 struct btrfs_path *path;
2509 u64 nr = 0;
2510 u64 cur_byte;
2511 u64 old_size;
2512 unsigned long rem;
2513 struct btrfs_block_group_cache *cache;
2514 struct btrfs_block_group_item *item;
2515 struct btrfs_fs_info *info = root->fs_info;
2516 struct extent_map_tree *block_group_cache;
2517 struct btrfs_key key;
2518 struct extent_buffer *leaf;
2519 int ret;
2520 int bit;
2521
2522 old_size = btrfs_super_total_bytes(&info->super_copy);
2523 block_group_cache = &info->block_group_cache;
2524
2525 root = info->extent_root;
2526
2527 cache = btrfs_lookup_block_group(root->fs_info, old_size - 1);
2528
2529 cur_byte = cache->key.objectid + cache->key.offset;
2530 if (cur_byte >= new_size)
2531 goto set_size;
2532
2533 key.offset = BTRFS_BLOCK_GROUP_SIZE;
2534 btrfs_set_key_type(&key, BTRFS_BLOCK_GROUP_ITEM_KEY);
2535
2536 path = btrfs_alloc_path();
2537 if (!path)
2538 return -ENOMEM;
2539
2540 while(cur_byte < new_size) {
2541 key.objectid = cur_byte;
2542 ret = btrfs_insert_empty_item(trans, root, path, &key,
2543 sizeof(struct btrfs_block_group_item));
2544 BUG_ON(ret);
2545 leaf = path->nodes[0];
2546 item = btrfs_item_ptr(leaf, path->slots[0],
2547 struct btrfs_block_group_item);
2548
2549 btrfs_set_disk_block_group_used(leaf, item, 0);
2550 div_long_long_rem(nr, 3, &rem);
2551 if (rem) {
2552 btrfs_set_disk_block_group_flags(leaf, item,
2553 BTRFS_BLOCK_GROUP_DATA);
2554 } else {
2555 btrfs_set_disk_block_group_flags(leaf, item, 0);
2556 }
2557 nr++;
2558
2559 cache = kmalloc(sizeof(*cache), GFP_NOFS);
2560 BUG_ON(!cache);
2561
2562 read_extent_buffer(leaf, &cache->item, (unsigned long)item,
2563 sizeof(cache->item));
2564
2565 memcpy(&cache->key, &key, sizeof(key));
2566 cache->cached = 0;
2567 cache->pinned = 0;
2568 cur_byte = key.objectid + key.offset;
2569 btrfs_release_path(root, path);
2570
2571 if (cache->item.flags & BTRFS_BLOCK_GROUP_DATA) {
2572 bit = BLOCK_GROUP_DATA;
2573 cache->data = BTRFS_BLOCK_GROUP_DATA;
2574 } else {
2575 bit = BLOCK_GROUP_METADATA;
2576 cache->data = 0;
2577 }
2578
2579 /* use EXTENT_LOCKED to prevent merging */
2580 set_extent_bits(block_group_cache, key.objectid,
2581 key.objectid + key.offset - 1,
2582 bit | EXTENT_LOCKED, GFP_NOFS);
2583 set_state_private(block_group_cache, key.objectid,
2584 (unsigned long)cache);
2585 }
2586 btrfs_free_path(path);
2587 set_size:
2588 btrfs_set_super_total_bytes(&info->super_copy, new_size);
2589 return 0;
2590 }
2591
2592 int btrfs_read_block_groups(struct btrfs_root *root)
2593 {
2594 struct btrfs_path *path;
2595 int ret;
2596 int err = 0;
2597 int bit;
2598 struct btrfs_block_group_cache *cache;
2599 struct btrfs_fs_info *info = root->fs_info;
2600 struct extent_map_tree *block_group_cache;
2601 struct btrfs_key key;
2602 struct btrfs_key found_key;
2603 struct extent_buffer *leaf;
2604
2605 block_group_cache = &info->block_group_cache;
2606
2607 root = info->extent_root;
2608 key.objectid = 0;
2609 key.offset = BTRFS_BLOCK_GROUP_SIZE;
2610 btrfs_set_key_type(&key, BTRFS_BLOCK_GROUP_ITEM_KEY);
2611
2612 path = btrfs_alloc_path();
2613 if (!path)
2614 return -ENOMEM;
2615
2616 while(1) {
2617 ret = btrfs_search_slot(NULL, info->extent_root,
2618 &key, path, 0, 0);
2619 if (ret != 0) {
2620 err = ret;
2621 break;
2622 }
2623 leaf = path->nodes[0];
2624 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
2625 cache = kmalloc(sizeof(*cache), GFP_NOFS);
2626 if (!cache) {
2627 err = -1;
2628 break;
2629 }
2630
2631 read_extent_buffer(leaf, &cache->item,
2632 btrfs_item_ptr_offset(leaf, path->slots[0]),
2633 sizeof(cache->item));
2634 memcpy(&cache->key, &found_key, sizeof(found_key));
2635 cache->cached = 0;
2636 cache->pinned = 0;
2637 key.objectid = found_key.objectid + found_key.offset;
2638 btrfs_release_path(root, path);
2639
2640 if (cache->item.flags & BTRFS_BLOCK_GROUP_MIXED) {
2641 bit = BLOCK_GROUP_DATA | BLOCK_GROUP_METADATA;
2642 cache->data = BTRFS_BLOCK_GROUP_MIXED;
2643 } else if (cache->item.flags & BTRFS_BLOCK_GROUP_DATA) {
2644 bit = BLOCK_GROUP_DATA;
2645 cache->data = BTRFS_BLOCK_GROUP_DATA;
2646 } else {
2647 bit = BLOCK_GROUP_METADATA;
2648 cache->data = 0;
2649 }
2650
2651 /* use EXTENT_LOCKED to prevent merging */
2652 set_extent_bits(block_group_cache, found_key.objectid,
2653 found_key.objectid + found_key.offset - 1,
2654 bit | EXTENT_LOCKED, GFP_NOFS);
2655 set_state_private(block_group_cache, found_key.objectid,
2656 (unsigned long)cache);
2657
2658 if (key.objectid >=
2659 btrfs_super_total_bytes(&info->super_copy))
2660 break;
2661 }
2662
2663 btrfs_free_path(path);
2664 return 0;
2665 }
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