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Btrfs: Fix NULL block groups on reading the inode
[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 <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 static u64 find_search_start(struct btrfs_root *root,
166 struct btrfs_block_group_cache **cache_ret,
167 u64 search_start, int num,
168 int data, int full_scan)
169 {
170 int ret;
171 struct btrfs_block_group_cache *cache = *cache_ret;
172 u64 last;
173 u64 start = 0;
174 u64 end = 0;
175 u64 cache_miss = 0;
176 int wrapped = 0;
177
178 if (!cache) {
179 goto out;
180 }
181 again:
182 ret = cache_block_group(root, cache);
183 if (ret)
184 goto out;
185
186 last = max(search_start, cache->key.objectid);
187
188 while(1) {
189 ret = find_first_extent_bit(&root->fs_info->free_space_cache,
190 last, &start, &end, EXTENT_DIRTY);
191 if (ret) {
192 if (!cache_miss)
193 cache_miss = last;
194 goto new_group;
195 }
196
197 start = max(last, start);
198 last = end + 1;
199 if (last - start < num) {
200 if (last == cache->key.objectid + cache->key.offset)
201 cache_miss = start;
202 continue;
203 }
204 if (data != BTRFS_BLOCK_GROUP_MIXED &&
205 start + num > cache->key.objectid + cache->key.offset)
206 goto new_group;
207 return start;
208 }
209 out:
210 cache = btrfs_lookup_block_group(root->fs_info, search_start);
211 if (!cache) {
212 printk("Unable to find block group for %Lu\n",
213 search_start);
214 WARN_ON(1);
215 return search_start;
216 }
217 return search_start;
218
219 new_group:
220 last = cache->key.objectid + cache->key.offset;
221 wrapped:
222 cache = btrfs_lookup_block_group(root->fs_info, last);
223 if (!cache) {
224 no_cache:
225 if (!wrapped) {
226 wrapped = 1;
227 last = search_start;
228 data = BTRFS_BLOCK_GROUP_MIXED;
229 goto wrapped;
230 }
231 goto out;
232 }
233 if (cache_miss && !cache->cached) {
234 cache_block_group(root, cache);
235 last = cache_miss;
236 cache = btrfs_lookup_block_group(root->fs_info, last);
237 }
238 cache = btrfs_find_block_group(root, cache, last, data, 0);
239 if (!cache)
240 goto no_cache;
241 *cache_ret = cache;
242 cache_miss = 0;
243 goto again;
244 }
245
246 static u64 div_factor(u64 num, int factor)
247 {
248 if (factor == 10)
249 return num;
250 num *= factor;
251 do_div(num, 10);
252 return num;
253 }
254
255 struct btrfs_block_group_cache *btrfs_find_block_group(struct btrfs_root *root,
256 struct btrfs_block_group_cache
257 *hint, u64 search_start,
258 int data, int owner)
259 {
260 struct btrfs_block_group_cache *cache;
261 struct extent_map_tree *block_group_cache;
262 struct btrfs_block_group_cache *found_group = NULL;
263 struct btrfs_fs_info *info = root->fs_info;
264 u64 used;
265 u64 last = 0;
266 u64 hint_last;
267 u64 start;
268 u64 end;
269 u64 free_check;
270 u64 ptr;
271 int bit;
272 int ret;
273 int full_search = 0;
274 int factor = 8;
275 int data_swap = 0;
276
277 block_group_cache = &info->block_group_cache;
278
279 if (!owner)
280 factor = 8;
281
282 if (data == BTRFS_BLOCK_GROUP_MIXED) {
283 bit = BLOCK_GROUP_DATA | BLOCK_GROUP_METADATA;
284 factor = 10;
285 } else if (data)
286 bit = BLOCK_GROUP_DATA;
287 else
288 bit = BLOCK_GROUP_METADATA;
289
290 if (search_start) {
291 struct btrfs_block_group_cache *shint;
292 shint = btrfs_lookup_block_group(info, search_start);
293 if (shint && (shint->data == data ||
294 shint->data == BTRFS_BLOCK_GROUP_MIXED)) {
295 used = btrfs_block_group_used(&shint->item);
296 if (used + shint->pinned <
297 div_factor(shint->key.offset, factor)) {
298 return shint;
299 }
300 }
301 }
302 if (hint && (hint->data == data ||
303 hint->data == BTRFS_BLOCK_GROUP_MIXED)) {
304 used = btrfs_block_group_used(&hint->item);
305 if (used + hint->pinned <
306 div_factor(hint->key.offset, factor)) {
307 return hint;
308 }
309 last = hint->key.objectid + hint->key.offset;
310 hint_last = last;
311 } else {
312 if (hint)
313 hint_last = max(hint->key.objectid, search_start);
314 else
315 hint_last = search_start;
316
317 last = hint_last;
318 }
319 again:
320 while(1) {
321 ret = find_first_extent_bit(block_group_cache, last,
322 &start, &end, bit);
323 if (ret)
324 break;
325
326 ret = get_state_private(block_group_cache, start, &ptr);
327 if (ret)
328 break;
329
330 cache = (struct btrfs_block_group_cache *)(unsigned long)ptr;
331 last = cache->key.objectid + cache->key.offset;
332 used = btrfs_block_group_used(&cache->item);
333
334 if (full_search)
335 free_check = cache->key.offset;
336 else
337 free_check = div_factor(cache->key.offset, factor);
338 if (used + cache->pinned < free_check) {
339 found_group = cache;
340 goto found;
341 }
342 cond_resched();
343 }
344 if (!full_search) {
345 last = search_start;
346 full_search = 1;
347 goto again;
348 }
349 if (!data_swap) {
350 data_swap = 1;
351 bit = BLOCK_GROUP_DATA | BLOCK_GROUP_METADATA;
352 last = search_start;
353 goto again;
354 }
355 found:
356 return found_group;
357 }
358
359 static u64 hash_extent_ref(u64 root_objectid, u64 ref_generation,
360 u64 owner, u64 owner_offset)
361 {
362 u32 high_crc = ~(u32)0;
363 u32 low_crc = ~(u32)0;
364 __le64 lenum;
365
366 lenum = cpu_to_le64(root_objectid);
367 high_crc = crc32c(high_crc, &lenum, sizeof(lenum));
368 lenum = cpu_to_le64(ref_generation);
369 low_crc = crc32c(low_crc, &lenum, sizeof(lenum));
370
371 #if 0
372 lenum = cpu_to_le64(owner);
373 low_crc = crc32c(low_crc, &lenum, sizeof(lenum));
374 lenum = cpu_to_le64(owner_offset);
375 low_crc = crc32c(low_crc, &lenum, sizeof(lenum));
376 #endif
377 return ((u64)high_crc << 32) | (u64)low_crc;
378 }
379
380 static int match_extent_ref(struct extent_buffer *leaf,
381 struct btrfs_extent_ref *disk_ref,
382 struct btrfs_extent_ref *cpu_ref)
383 {
384 int ret;
385 int len;
386
387 if (cpu_ref->objectid)
388 len = sizeof(*cpu_ref);
389 else
390 len = 2 * sizeof(u64);
391 ret = memcmp_extent_buffer(leaf, cpu_ref, (unsigned long)disk_ref,
392 len);
393 return ret == 0;
394 }
395
396 static int lookup_extent_backref(struct btrfs_trans_handle *trans,
397 struct btrfs_root *root,
398 struct btrfs_path *path, u64 bytenr,
399 u64 root_objectid, u64 ref_generation,
400 u64 owner, u64 owner_offset, int del)
401 {
402 u64 hash;
403 struct btrfs_key key;
404 struct btrfs_key found_key;
405 struct btrfs_extent_ref ref;
406 struct extent_buffer *leaf;
407 struct btrfs_extent_ref *disk_ref;
408 int ret;
409 int ret2;
410
411 btrfs_set_stack_ref_root(&ref, root_objectid);
412 btrfs_set_stack_ref_generation(&ref, ref_generation);
413 btrfs_set_stack_ref_objectid(&ref, owner);
414 btrfs_set_stack_ref_offset(&ref, owner_offset);
415
416 hash = hash_extent_ref(root_objectid, ref_generation, owner,
417 owner_offset);
418 key.offset = hash;
419 key.objectid = bytenr;
420 key.type = BTRFS_EXTENT_REF_KEY;
421
422 while (1) {
423 ret = btrfs_search_slot(trans, root, &key, path,
424 del ? -1 : 0, del);
425 if (ret < 0)
426 goto out;
427 leaf = path->nodes[0];
428 if (ret != 0) {
429 u32 nritems = btrfs_header_nritems(leaf);
430 if (path->slots[0] >= nritems) {
431 ret2 = btrfs_next_leaf(root, path);
432 if (ret2)
433 goto out;
434 leaf = path->nodes[0];
435 }
436 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
437 if (found_key.objectid != bytenr ||
438 found_key.type != BTRFS_EXTENT_REF_KEY)
439 goto out;
440 key.offset = found_key.offset;
441 if (del) {
442 btrfs_release_path(root, path);
443 continue;
444 }
445 }
446 disk_ref = btrfs_item_ptr(path->nodes[0],
447 path->slots[0],
448 struct btrfs_extent_ref);
449 if (match_extent_ref(path->nodes[0], disk_ref, &ref)) {
450 ret = 0;
451 goto out;
452 }
453 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
454 key.offset = found_key.offset + 1;
455 btrfs_release_path(root, path);
456 }
457 out:
458 return ret;
459 }
460
461 /*
462 * Back reference rules. Back refs have three main goals:
463 *
464 * 1) differentiate between all holders of references to an extent so that
465 * when a reference is dropped we can make sure it was a valid reference
466 * before freeing the extent.
467 *
468 * 2) Provide enough information to quickly find the holders of an extent
469 * if we notice a given block is corrupted or bad.
470 *
471 * 3) Make it easy to migrate blocks for FS shrinking or storage pool
472 * maintenance. This is actually the same as #2, but with a slightly
473 * different use case.
474 *
475 * File extents can be referenced by:
476 *
477 * - multiple snapshots, subvolumes, or different generations in one subvol
478 * - different files inside a single subvolume (in theory, not implemented yet)
479 * - different offsets inside a file (bookend extents in file.c)
480 *
481 * The extent ref structure has fields for:
482 *
483 * - Objectid of the subvolume root
484 * - Generation number of the tree holding the reference
485 * - objectid of the file holding the reference
486 * - offset in the file corresponding to the key holding the reference
487 *
488 * When a file extent is allocated the fields are filled in:
489 * (root_key.objectid, trans->transid, inode objectid, offset in file)
490 *
491 * When a leaf is cow'd new references are added for every file extent found
492 * in the leaf. It looks the same as the create case, but trans->transid
493 * will be different when the block is cow'd.
494 *
495 * (root_key.objectid, trans->transid, inode objectid, offset in file)
496 *
497 * When a file extent is removed either during snapshot deletion or file
498 * truncation, the corresponding back reference is found
499 * by searching for:
500 *
501 * (btrfs_header_owner(leaf), btrfs_header_generation(leaf),
502 * inode objectid, offset in file)
503 *
504 * Btree extents can be referenced by:
505 *
506 * - Different subvolumes
507 * - Different generations of the same subvolume
508 *
509 * Storing sufficient information for a full reverse mapping of a btree
510 * block would require storing the lowest key of the block in the backref,
511 * and it would require updating that lowest key either before write out or
512 * every time it changed. Instead, the objectid of the lowest key is stored
513 * along with the level of the tree block. This provides a hint
514 * about where in the btree the block can be found. Searches through the
515 * btree only need to look for a pointer to that block, so they stop one
516 * level higher than the level recorded in the backref.
517 *
518 * Some btrees do not do reference counting on their extents. These
519 * include the extent tree and the tree of tree roots. Backrefs for these
520 * trees always have a generation of zero.
521 *
522 * When a tree block is created, back references are inserted:
523 *
524 * (root->root_key.objectid, trans->transid or zero, level, lowest_key_objectid)
525 *
526 * When a tree block is cow'd in a reference counted root,
527 * new back references are added for all the blocks it points to.
528 * These are of the form (trans->transid will have increased since creation):
529 *
530 * (root->root_key.objectid, trans->transid, level, lowest_key_objectid)
531 *
532 * Because the lowest_key_objectid and the level are just hints
533 * they are not used when backrefs are deleted. When a backref is deleted:
534 *
535 * if backref was for a tree root:
536 * root_objectid = root->root_key.objectid
537 * else
538 * root_objectid = btrfs_header_owner(parent)
539 *
540 * (root_objectid, btrfs_header_generation(parent) or zero, 0, 0)
541 *
542 * Back Reference Key hashing:
543 *
544 * Back references have four fields, each 64 bits long. Unfortunately,
545 * This is hashed into a single 64 bit number and placed into the key offset.
546 * The key objectid corresponds to the first byte in the extent, and the
547 * key type is set to BTRFS_EXTENT_REF_KEY
548 */
549 int btrfs_insert_extent_backref(struct btrfs_trans_handle *trans,
550 struct btrfs_root *root,
551 struct btrfs_path *path, u64 bytenr,
552 u64 root_objectid, u64 ref_generation,
553 u64 owner, u64 owner_offset)
554 {
555 u64 hash;
556 struct btrfs_key key;
557 struct btrfs_extent_ref ref;
558 struct btrfs_extent_ref *disk_ref;
559 int ret;
560
561 btrfs_set_stack_ref_root(&ref, root_objectid);
562 btrfs_set_stack_ref_generation(&ref, ref_generation);
563 btrfs_set_stack_ref_objectid(&ref, owner);
564 btrfs_set_stack_ref_offset(&ref, owner_offset);
565
566 hash = hash_extent_ref(root_objectid, ref_generation, owner,
567 owner_offset);
568 key.offset = hash;
569 key.objectid = bytenr;
570 key.type = BTRFS_EXTENT_REF_KEY;
571
572 ret = btrfs_insert_empty_item(trans, root, path, &key, sizeof(ref));
573 while (ret == -EEXIST) {
574 disk_ref = btrfs_item_ptr(path->nodes[0], path->slots[0],
575 struct btrfs_extent_ref);
576 if (match_extent_ref(path->nodes[0], disk_ref, &ref))
577 goto out;
578 key.offset++;
579 btrfs_release_path(root, path);
580 ret = btrfs_insert_empty_item(trans, root, path, &key,
581 sizeof(ref));
582 }
583 if (ret)
584 goto out;
585 disk_ref = btrfs_item_ptr(path->nodes[0], path->slots[0],
586 struct btrfs_extent_ref);
587 write_extent_buffer(path->nodes[0], &ref, (unsigned long)disk_ref,
588 sizeof(ref));
589 btrfs_mark_buffer_dirty(path->nodes[0]);
590 out:
591 btrfs_release_path(root, path);
592 return ret;
593 }
594
595 int btrfs_inc_extent_ref(struct btrfs_trans_handle *trans,
596 struct btrfs_root *root,
597 u64 bytenr, u64 num_bytes,
598 u64 root_objectid, u64 ref_generation,
599 u64 owner, u64 owner_offset)
600 {
601 struct btrfs_path *path;
602 int ret;
603 struct btrfs_key key;
604 struct extent_buffer *l;
605 struct btrfs_extent_item *item;
606 u32 refs;
607
608 WARN_ON(num_bytes < root->sectorsize);
609 path = btrfs_alloc_path();
610 if (!path)
611 return -ENOMEM;
612
613 key.objectid = bytenr;
614 btrfs_set_key_type(&key, BTRFS_EXTENT_ITEM_KEY);
615 key.offset = num_bytes;
616 ret = btrfs_search_slot(trans, root->fs_info->extent_root, &key, path,
617 0, 1);
618 if (ret < 0)
619 return ret;
620 if (ret != 0) {
621 BUG();
622 }
623 BUG_ON(ret != 0);
624 l = path->nodes[0];
625 item = btrfs_item_ptr(l, path->slots[0], struct btrfs_extent_item);
626 refs = btrfs_extent_refs(l, item);
627 btrfs_set_extent_refs(l, item, refs + 1);
628 btrfs_mark_buffer_dirty(path->nodes[0]);
629
630 btrfs_release_path(root->fs_info->extent_root, path);
631
632 ret = btrfs_insert_extent_backref(trans, root->fs_info->extent_root,
633 path, bytenr, root_objectid,
634 ref_generation, owner, owner_offset);
635 BUG_ON(ret);
636 finish_current_insert(trans, root->fs_info->extent_root);
637 del_pending_extents(trans, root->fs_info->extent_root);
638
639 btrfs_free_path(path);
640 return 0;
641 }
642
643 int btrfs_extent_post_op(struct btrfs_trans_handle *trans,
644 struct btrfs_root *root)
645 {
646 finish_current_insert(trans, root->fs_info->extent_root);
647 del_pending_extents(trans, root->fs_info->extent_root);
648 return 0;
649 }
650
651 static int lookup_extent_ref(struct btrfs_trans_handle *trans,
652 struct btrfs_root *root, u64 bytenr,
653 u64 num_bytes, u32 *refs)
654 {
655 struct btrfs_path *path;
656 int ret;
657 struct btrfs_key key;
658 struct extent_buffer *l;
659 struct btrfs_extent_item *item;
660
661 WARN_ON(num_bytes < root->sectorsize);
662 path = btrfs_alloc_path();
663 key.objectid = bytenr;
664 key.offset = num_bytes;
665 btrfs_set_key_type(&key, BTRFS_EXTENT_ITEM_KEY);
666 ret = btrfs_search_slot(trans, root->fs_info->extent_root, &key, path,
667 0, 0);
668 if (ret < 0)
669 goto out;
670 if (ret != 0) {
671 btrfs_print_leaf(root, path->nodes[0]);
672 printk("failed to find block number %Lu\n", bytenr);
673 BUG();
674 }
675 l = path->nodes[0];
676 item = btrfs_item_ptr(l, path->slots[0], struct btrfs_extent_item);
677 *refs = btrfs_extent_refs(l, item);
678 out:
679 btrfs_free_path(path);
680 return 0;
681 }
682
683 u32 btrfs_count_snapshots_in_path(struct btrfs_root *root,
684 struct btrfs_path *count_path,
685 u64 first_extent)
686 {
687 struct btrfs_root *extent_root = root->fs_info->extent_root;
688 struct btrfs_path *path;
689 u64 bytenr;
690 u64 found_objectid;
691 u64 root_objectid = 0;
692 u32 total_count = 0;
693 u32 cur_count;
694 u32 refs;
695 u32 nritems;
696 int ret;
697 struct btrfs_key key;
698 struct btrfs_key found_key;
699 struct extent_buffer *l;
700 struct btrfs_extent_item *item;
701 struct btrfs_extent_ref *ref_item;
702 int level = -1;
703
704 path = btrfs_alloc_path();
705 again:
706 if (level == -1)
707 bytenr = first_extent;
708 else
709 bytenr = count_path->nodes[level]->start;
710
711 cur_count = 0;
712 key.objectid = bytenr;
713 key.offset = 0;
714
715 btrfs_set_key_type(&key, BTRFS_EXTENT_ITEM_KEY);
716 ret = btrfs_search_slot(NULL, extent_root, &key, path, 0, 0);
717 if (ret < 0)
718 goto out;
719 BUG_ON(ret == 0);
720
721 l = path->nodes[0];
722 btrfs_item_key_to_cpu(l, &found_key, path->slots[0]);
723
724 if (found_key.objectid != bytenr ||
725 found_key.type != BTRFS_EXTENT_ITEM_KEY) {
726 goto out;
727 }
728
729 item = btrfs_item_ptr(l, path->slots[0], struct btrfs_extent_item);
730 refs = btrfs_extent_refs(l, item);
731 while (1) {
732 nritems = btrfs_header_nritems(l);
733 if (path->slots[0] >= nritems) {
734 ret = btrfs_next_leaf(extent_root, path);
735 if (ret == 0)
736 continue;
737 break;
738 }
739 btrfs_item_key_to_cpu(l, &found_key, path->slots[0]);
740 if (found_key.objectid != bytenr)
741 break;
742 if (found_key.type != BTRFS_EXTENT_REF_KEY) {
743 path->slots[0]++;
744 continue;
745 }
746
747 cur_count++;
748 ref_item = btrfs_item_ptr(l, path->slots[0],
749 struct btrfs_extent_ref);
750 found_objectid = btrfs_ref_root(l, ref_item);
751
752 if (found_objectid != root_objectid)
753 total_count++;
754
755 if (total_count > 1)
756 goto out;
757
758 if (root_objectid == 0)
759 root_objectid = found_objectid;
760
761 path->slots[0]++;
762 }
763 if (cur_count == 0) {
764 total_count = 0;
765 goto out;
766 }
767 if (total_count > 1)
768 goto out;
769 if (level >= 0 && root->node == count_path->nodes[level])
770 goto out;
771 level++;
772 btrfs_release_path(root, path);
773 goto again;
774
775 out:
776 btrfs_free_path(path);
777 return total_count;
778
779 }
780
781 int btrfs_inc_root_ref(struct btrfs_trans_handle *trans,
782 struct btrfs_root *root, u64 owner_objectid)
783 {
784 u64 generation;
785 u64 key_objectid;
786 u64 level;
787 u32 nritems;
788 struct btrfs_disk_key disk_key;
789
790 level = btrfs_header_level(root->node);
791 generation = trans->transid;
792 nritems = btrfs_header_nritems(root->node);
793 if (nritems > 0) {
794 if (level == 0)
795 btrfs_item_key(root->node, &disk_key, 0);
796 else
797 btrfs_node_key(root->node, &disk_key, 0);
798 key_objectid = btrfs_disk_key_objectid(&disk_key);
799 } else {
800 key_objectid = 0;
801 }
802 return btrfs_inc_extent_ref(trans, root, root->node->start,
803 root->node->len, owner_objectid,
804 generation, level, key_objectid);
805 }
806
807 int btrfs_inc_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root,
808 struct extent_buffer *buf)
809 {
810 u64 bytenr;
811 u32 nritems;
812 struct btrfs_key key;
813 struct btrfs_file_extent_item *fi;
814 int i;
815 int level;
816 int ret;
817 int faili;
818
819 if (!root->ref_cows)
820 return 0;
821
822 level = btrfs_header_level(buf);
823 nritems = btrfs_header_nritems(buf);
824 for (i = 0; i < nritems; i++) {
825 if (level == 0) {
826 u64 disk_bytenr;
827 btrfs_item_key_to_cpu(buf, &key, i);
828 if (btrfs_key_type(&key) != BTRFS_EXTENT_DATA_KEY)
829 continue;
830 fi = btrfs_item_ptr(buf, i,
831 struct btrfs_file_extent_item);
832 if (btrfs_file_extent_type(buf, fi) ==
833 BTRFS_FILE_EXTENT_INLINE)
834 continue;
835 disk_bytenr = btrfs_file_extent_disk_bytenr(buf, fi);
836 if (disk_bytenr == 0)
837 continue;
838 ret = btrfs_inc_extent_ref(trans, root, disk_bytenr,
839 btrfs_file_extent_disk_num_bytes(buf, fi),
840 root->root_key.objectid, trans->transid,
841 key.objectid, key.offset);
842 if (ret) {
843 faili = i;
844 goto fail;
845 }
846 } else {
847 bytenr = btrfs_node_blockptr(buf, i);
848 btrfs_node_key_to_cpu(buf, &key, i);
849 ret = btrfs_inc_extent_ref(trans, root, bytenr,
850 btrfs_level_size(root, level - 1),
851 root->root_key.objectid,
852 trans->transid,
853 level - 1, key.objectid);
854 if (ret) {
855 faili = i;
856 goto fail;
857 }
858 }
859 }
860 return 0;
861 fail:
862 WARN_ON(1);
863 #if 0
864 for (i =0; i < faili; i++) {
865 if (level == 0) {
866 u64 disk_bytenr;
867 btrfs_item_key_to_cpu(buf, &key, i);
868 if (btrfs_key_type(&key) != BTRFS_EXTENT_DATA_KEY)
869 continue;
870 fi = btrfs_item_ptr(buf, i,
871 struct btrfs_file_extent_item);
872 if (btrfs_file_extent_type(buf, fi) ==
873 BTRFS_FILE_EXTENT_INLINE)
874 continue;
875 disk_bytenr = btrfs_file_extent_disk_bytenr(buf, fi);
876 if (disk_bytenr == 0)
877 continue;
878 err = btrfs_free_extent(trans, root, disk_bytenr,
879 btrfs_file_extent_disk_num_bytes(buf,
880 fi), 0);
881 BUG_ON(err);
882 } else {
883 bytenr = btrfs_node_blockptr(buf, i);
884 err = btrfs_free_extent(trans, root, bytenr,
885 btrfs_level_size(root, level - 1), 0);
886 BUG_ON(err);
887 }
888 }
889 #endif
890 return ret;
891 }
892
893 static int write_one_cache_group(struct btrfs_trans_handle *trans,
894 struct btrfs_root *root,
895 struct btrfs_path *path,
896 struct btrfs_block_group_cache *cache)
897 {
898 int ret;
899 int pending_ret;
900 struct btrfs_root *extent_root = root->fs_info->extent_root;
901 unsigned long bi;
902 struct extent_buffer *leaf;
903
904 ret = btrfs_search_slot(trans, extent_root, &cache->key, path, 0, 1);
905 if (ret < 0)
906 goto fail;
907 BUG_ON(ret);
908
909 leaf = path->nodes[0];
910 bi = btrfs_item_ptr_offset(leaf, path->slots[0]);
911 write_extent_buffer(leaf, &cache->item, bi, sizeof(cache->item));
912 btrfs_mark_buffer_dirty(leaf);
913 btrfs_release_path(extent_root, path);
914 fail:
915 finish_current_insert(trans, extent_root);
916 pending_ret = del_pending_extents(trans, extent_root);
917 if (ret)
918 return ret;
919 if (pending_ret)
920 return pending_ret;
921 return 0;
922
923 }
924
925 int btrfs_write_dirty_block_groups(struct btrfs_trans_handle *trans,
926 struct btrfs_root *root)
927 {
928 struct extent_map_tree *block_group_cache;
929 struct btrfs_block_group_cache *cache;
930 int ret;
931 int err = 0;
932 int werr = 0;
933 struct btrfs_path *path;
934 u64 last = 0;
935 u64 start;
936 u64 end;
937 u64 ptr;
938
939 block_group_cache = &root->fs_info->block_group_cache;
940 path = btrfs_alloc_path();
941 if (!path)
942 return -ENOMEM;
943
944 while(1) {
945 ret = find_first_extent_bit(block_group_cache, last,
946 &start, &end, BLOCK_GROUP_DIRTY);
947 if (ret)
948 break;
949
950 last = end + 1;
951 ret = get_state_private(block_group_cache, start, &ptr);
952 if (ret)
953 break;
954
955 cache = (struct btrfs_block_group_cache *)(unsigned long)ptr;
956 err = write_one_cache_group(trans, root,
957 path, cache);
958 /*
959 * if we fail to write the cache group, we want
960 * to keep it marked dirty in hopes that a later
961 * write will work
962 */
963 if (err) {
964 werr = err;
965 continue;
966 }
967 clear_extent_bits(block_group_cache, start, end,
968 BLOCK_GROUP_DIRTY, GFP_NOFS);
969 }
970 btrfs_free_path(path);
971 return werr;
972 }
973
974 static int update_block_group(struct btrfs_trans_handle *trans,
975 struct btrfs_root *root,
976 u64 bytenr, u64 num_bytes, int alloc,
977 int mark_free, int data)
978 {
979 struct btrfs_block_group_cache *cache;
980 struct btrfs_fs_info *info = root->fs_info;
981 u64 total = num_bytes;
982 u64 old_val;
983 u64 byte_in_group;
984 u64 start;
985 u64 end;
986
987 while(total) {
988 cache = btrfs_lookup_block_group(info, bytenr);
989 if (!cache) {
990 return -1;
991 }
992 byte_in_group = bytenr - cache->key.objectid;
993 WARN_ON(byte_in_group > cache->key.offset);
994 start = cache->key.objectid;
995 end = start + cache->key.offset - 1;
996 set_extent_bits(&info->block_group_cache, start, end,
997 BLOCK_GROUP_DIRTY, GFP_NOFS);
998
999 old_val = btrfs_block_group_used(&cache->item);
1000 num_bytes = min(total, cache->key.offset - byte_in_group);
1001 if (alloc) {
1002 if (cache->data != data &&
1003 old_val < (cache->key.offset >> 1)) {
1004 int bit_to_clear;
1005 int bit_to_set;
1006 cache->data = data;
1007 if (data) {
1008 bit_to_clear = BLOCK_GROUP_METADATA;
1009 bit_to_set = BLOCK_GROUP_DATA;
1010 cache->item.flags &=
1011 ~BTRFS_BLOCK_GROUP_MIXED;
1012 cache->item.flags |=
1013 BTRFS_BLOCK_GROUP_DATA;
1014 } else {
1015 bit_to_clear = BLOCK_GROUP_DATA;
1016 bit_to_set = BLOCK_GROUP_METADATA;
1017 cache->item.flags &=
1018 ~BTRFS_BLOCK_GROUP_MIXED;
1019 cache->item.flags &=
1020 ~BTRFS_BLOCK_GROUP_DATA;
1021 }
1022 clear_extent_bits(&info->block_group_cache,
1023 start, end, bit_to_clear,
1024 GFP_NOFS);
1025 set_extent_bits(&info->block_group_cache,
1026 start, end, bit_to_set,
1027 GFP_NOFS);
1028 } else if (cache->data != data &&
1029 cache->data != BTRFS_BLOCK_GROUP_MIXED) {
1030 cache->data = BTRFS_BLOCK_GROUP_MIXED;
1031 set_extent_bits(&info->block_group_cache,
1032 start, end,
1033 BLOCK_GROUP_DATA |
1034 BLOCK_GROUP_METADATA,
1035 GFP_NOFS);
1036 }
1037 old_val += num_bytes;
1038 } else {
1039 old_val -= num_bytes;
1040 if (mark_free) {
1041 set_extent_dirty(&info->free_space_cache,
1042 bytenr, bytenr + num_bytes - 1,
1043 GFP_NOFS);
1044 }
1045 }
1046 btrfs_set_block_group_used(&cache->item, old_val);
1047 total -= num_bytes;
1048 bytenr += num_bytes;
1049 }
1050 return 0;
1051 }
1052 static int update_pinned_extents(struct btrfs_root *root,
1053 u64 bytenr, u64 num, int pin)
1054 {
1055 u64 len;
1056 struct btrfs_block_group_cache *cache;
1057 struct btrfs_fs_info *fs_info = root->fs_info;
1058
1059 if (pin) {
1060 set_extent_dirty(&fs_info->pinned_extents,
1061 bytenr, bytenr + num - 1, GFP_NOFS);
1062 } else {
1063 clear_extent_dirty(&fs_info->pinned_extents,
1064 bytenr, bytenr + num - 1, GFP_NOFS);
1065 }
1066 while (num > 0) {
1067 cache = btrfs_lookup_block_group(fs_info, bytenr);
1068 WARN_ON(!cache);
1069 len = min(num, cache->key.offset -
1070 (bytenr - cache->key.objectid));
1071 if (pin) {
1072 cache->pinned += len;
1073 fs_info->total_pinned += len;
1074 } else {
1075 cache->pinned -= len;
1076 fs_info->total_pinned -= len;
1077 }
1078 bytenr += len;
1079 num -= len;
1080 }
1081 return 0;
1082 }
1083
1084 int btrfs_copy_pinned(struct btrfs_root *root, struct extent_map_tree *copy)
1085 {
1086 u64 last = 0;
1087 u64 start;
1088 u64 end;
1089 struct extent_map_tree *pinned_extents = &root->fs_info->pinned_extents;
1090 int ret;
1091
1092 while(1) {
1093 ret = find_first_extent_bit(pinned_extents, last,
1094 &start, &end, EXTENT_DIRTY);
1095 if (ret)
1096 break;
1097 set_extent_dirty(copy, start, end, GFP_NOFS);
1098 last = end + 1;
1099 }
1100 return 0;
1101 }
1102
1103 int btrfs_finish_extent_commit(struct btrfs_trans_handle *trans,
1104 struct btrfs_root *root,
1105 struct extent_map_tree *unpin)
1106 {
1107 u64 start;
1108 u64 end;
1109 int ret;
1110 struct extent_map_tree *free_space_cache;
1111 free_space_cache = &root->fs_info->free_space_cache;
1112
1113 while(1) {
1114 ret = find_first_extent_bit(unpin, 0, &start, &end,
1115 EXTENT_DIRTY);
1116 if (ret)
1117 break;
1118 update_pinned_extents(root, start, end + 1 - start, 0);
1119 clear_extent_dirty(unpin, start, end, GFP_NOFS);
1120 set_extent_dirty(free_space_cache, start, end, GFP_NOFS);
1121 }
1122 return 0;
1123 }
1124
1125 static int finish_current_insert(struct btrfs_trans_handle *trans, struct
1126 btrfs_root *extent_root)
1127 {
1128 u64 start;
1129 u64 end;
1130 struct btrfs_fs_info *info = extent_root->fs_info;
1131 struct extent_buffer *eb;
1132 struct btrfs_path *path;
1133 struct btrfs_key ins;
1134 struct btrfs_disk_key first;
1135 struct btrfs_extent_item extent_item;
1136 int ret;
1137 int level;
1138 int err = 0;
1139
1140 btrfs_set_stack_extent_refs(&extent_item, 1);
1141 btrfs_set_key_type(&ins, BTRFS_EXTENT_ITEM_KEY);
1142 path = btrfs_alloc_path();
1143
1144 while(1) {
1145 ret = find_first_extent_bit(&info->extent_ins, 0, &start,
1146 &end, EXTENT_LOCKED);
1147 if (ret)
1148 break;
1149
1150 ins.objectid = start;
1151 ins.offset = end + 1 - start;
1152 err = btrfs_insert_item(trans, extent_root, &ins,
1153 &extent_item, sizeof(extent_item));
1154 clear_extent_bits(&info->extent_ins, start, end, EXTENT_LOCKED,
1155 GFP_NOFS);
1156 eb = read_tree_block(extent_root, ins.objectid, ins.offset);
1157 level = btrfs_header_level(eb);
1158 if (level == 0) {
1159 btrfs_item_key(eb, &first, 0);
1160 } else {
1161 btrfs_node_key(eb, &first, 0);
1162 }
1163 err = btrfs_insert_extent_backref(trans, extent_root, path,
1164 start, extent_root->root_key.objectid,
1165 0, level,
1166 btrfs_disk_key_objectid(&first));
1167 BUG_ON(err);
1168 free_extent_buffer(eb);
1169 }
1170 btrfs_free_path(path);
1171 return 0;
1172 }
1173
1174 static int pin_down_bytes(struct btrfs_root *root, u64 bytenr, u32 num_bytes,
1175 int pending)
1176 {
1177 int err = 0;
1178 struct extent_buffer *buf;
1179
1180 if (!pending) {
1181 buf = btrfs_find_tree_block(root, bytenr, num_bytes);
1182 if (buf) {
1183 if (btrfs_buffer_uptodate(buf)) {
1184 u64 transid =
1185 root->fs_info->running_transaction->transid;
1186 if (btrfs_header_generation(buf) == transid) {
1187 free_extent_buffer(buf);
1188 return 1;
1189 }
1190 }
1191 free_extent_buffer(buf);
1192 }
1193 update_pinned_extents(root, bytenr, num_bytes, 1);
1194 } else {
1195 set_extent_bits(&root->fs_info->pending_del,
1196 bytenr, bytenr + num_bytes - 1,
1197 EXTENT_LOCKED, GFP_NOFS);
1198 }
1199 BUG_ON(err < 0);
1200 return 0;
1201 }
1202
1203 /*
1204 * remove an extent from the root, returns 0 on success
1205 */
1206 static int __free_extent(struct btrfs_trans_handle *trans, struct btrfs_root
1207 *root, u64 bytenr, u64 num_bytes,
1208 u64 root_objectid, u64 ref_generation,
1209 u64 owner_objectid, u64 owner_offset, int pin,
1210 int mark_free)
1211 {
1212 struct btrfs_path *path;
1213 struct btrfs_key key;
1214 struct btrfs_fs_info *info = root->fs_info;
1215 struct btrfs_root *extent_root = info->extent_root;
1216 struct extent_buffer *leaf;
1217 int ret;
1218 struct btrfs_extent_item *ei;
1219 u32 refs;
1220
1221 key.objectid = bytenr;
1222 btrfs_set_key_type(&key, BTRFS_EXTENT_ITEM_KEY);
1223 key.offset = num_bytes;
1224
1225 path = btrfs_alloc_path();
1226 if (!path)
1227 return -ENOMEM;
1228
1229 ret = lookup_extent_backref(trans, extent_root, path,
1230 bytenr, root_objectid,
1231 ref_generation,
1232 owner_objectid, owner_offset, 1);
1233 if (ret == 0) {
1234 ret = btrfs_del_item(trans, extent_root, path);
1235 } else {
1236 btrfs_print_leaf(extent_root, path->nodes[0]);
1237 WARN_ON(1);
1238 printk("Unable to find ref byte nr %Lu root %Lu "
1239 " gen %Lu owner %Lu offset %Lu\n", bytenr,
1240 root_objectid, ref_generation, owner_objectid,
1241 owner_offset);
1242 }
1243 btrfs_release_path(extent_root, path);
1244 ret = btrfs_search_slot(trans, extent_root, &key, path, -1, 1);
1245 if (ret < 0)
1246 return ret;
1247 BUG_ON(ret);
1248
1249 leaf = path->nodes[0];
1250 ei = btrfs_item_ptr(leaf, path->slots[0],
1251 struct btrfs_extent_item);
1252 refs = btrfs_extent_refs(leaf, ei);
1253 BUG_ON(refs == 0);
1254 refs -= 1;
1255 btrfs_set_extent_refs(leaf, ei, refs);
1256 btrfs_mark_buffer_dirty(leaf);
1257
1258 if (refs == 0) {
1259 u64 super_used;
1260 u64 root_used;
1261
1262 if (pin) {
1263 ret = pin_down_bytes(root, bytenr, num_bytes, 0);
1264 if (ret > 0)
1265 mark_free = 1;
1266 BUG_ON(ret < 0);
1267 }
1268
1269 /* block accounting for super block */
1270 super_used = btrfs_super_bytes_used(&info->super_copy);
1271 btrfs_set_super_bytes_used(&info->super_copy,
1272 super_used - num_bytes);
1273
1274 /* block accounting for root item */
1275 root_used = btrfs_root_used(&root->root_item);
1276 btrfs_set_root_used(&root->root_item,
1277 root_used - num_bytes);
1278
1279 ret = btrfs_del_item(trans, extent_root, path);
1280 if (ret) {
1281 return ret;
1282 }
1283 ret = update_block_group(trans, root, bytenr, num_bytes, 0,
1284 mark_free, 0);
1285 BUG_ON(ret);
1286 }
1287 btrfs_free_path(path);
1288 finish_current_insert(trans, extent_root);
1289 return ret;
1290 }
1291
1292 /*
1293 * find all the blocks marked as pending in the radix tree and remove
1294 * them from the extent map
1295 */
1296 static int del_pending_extents(struct btrfs_trans_handle *trans, struct
1297 btrfs_root *extent_root)
1298 {
1299 int ret;
1300 int err = 0;
1301 u64 start;
1302 u64 end;
1303 struct extent_map_tree *pending_del;
1304 struct extent_map_tree *pinned_extents;
1305
1306 pending_del = &extent_root->fs_info->pending_del;
1307 pinned_extents = &extent_root->fs_info->pinned_extents;
1308
1309 while(1) {
1310 ret = find_first_extent_bit(pending_del, 0, &start, &end,
1311 EXTENT_LOCKED);
1312 if (ret)
1313 break;
1314 update_pinned_extents(extent_root, start, end + 1 - start, 1);
1315 clear_extent_bits(pending_del, start, end, EXTENT_LOCKED,
1316 GFP_NOFS);
1317 ret = __free_extent(trans, extent_root,
1318 start, end + 1 - start,
1319 extent_root->root_key.objectid,
1320 0, 0, 0, 0, 0);
1321 if (ret)
1322 err = ret;
1323 }
1324 return err;
1325 }
1326
1327 /*
1328 * remove an extent from the root, returns 0 on success
1329 */
1330 int btrfs_free_extent(struct btrfs_trans_handle *trans, struct btrfs_root
1331 *root, u64 bytenr, u64 num_bytes,
1332 u64 root_objectid, u64 ref_generation,
1333 u64 owner_objectid, u64 owner_offset, int pin)
1334 {
1335 struct btrfs_root *extent_root = root->fs_info->extent_root;
1336 int pending_ret;
1337 int ret;
1338
1339 WARN_ON(num_bytes < root->sectorsize);
1340 if (!root->ref_cows)
1341 ref_generation = 0;
1342
1343 if (root == extent_root) {
1344 pin_down_bytes(root, bytenr, num_bytes, 1);
1345 return 0;
1346 }
1347 ret = __free_extent(trans, root, bytenr, num_bytes, root_objectid,
1348 ref_generation, owner_objectid, owner_offset,
1349 pin, pin == 0);
1350 pending_ret = del_pending_extents(trans, root->fs_info->extent_root);
1351 return ret ? ret : pending_ret;
1352 }
1353
1354 static u64 stripe_align(struct btrfs_root *root, u64 val)
1355 {
1356 u64 mask = ((u64)root->stripesize - 1);
1357 u64 ret = (val + mask) & ~mask;
1358 return ret;
1359 }
1360
1361 /*
1362 * walks the btree of allocated extents and find a hole of a given size.
1363 * The key ins is changed to record the hole:
1364 * ins->objectid == block start
1365 * ins->flags = BTRFS_EXTENT_ITEM_KEY
1366 * ins->offset == number of blocks
1367 * Any available blocks before search_start are skipped.
1368 */
1369 static int find_free_extent(struct btrfs_trans_handle *trans, struct btrfs_root
1370 *orig_root, u64 num_bytes, u64 empty_size,
1371 u64 search_start, u64 search_end, u64 hint_byte,
1372 struct btrfs_key *ins, u64 exclude_start,
1373 u64 exclude_nr, int data)
1374 {
1375 struct btrfs_path *path;
1376 struct btrfs_key key;
1377 u64 hole_size = 0;
1378 u64 aligned;
1379 int ret;
1380 int slot = 0;
1381 u64 last_byte = 0;
1382 u64 orig_search_start = search_start;
1383 int start_found;
1384 struct extent_buffer *l;
1385 struct btrfs_root * root = orig_root->fs_info->extent_root;
1386 struct btrfs_fs_info *info = root->fs_info;
1387 u64 total_needed = num_bytes;
1388 int level;
1389 struct btrfs_block_group_cache *block_group;
1390 int full_scan = 0;
1391 int wrapped = 0;
1392 u64 cached_start;
1393
1394 WARN_ON(num_bytes < root->sectorsize);
1395 btrfs_set_key_type(ins, BTRFS_EXTENT_ITEM_KEY);
1396
1397 level = btrfs_header_level(root->node);
1398
1399 if (num_bytes >= 32 * 1024 * 1024 && hint_byte) {
1400 data = BTRFS_BLOCK_GROUP_MIXED;
1401 }
1402
1403 if (search_end == (u64)-1)
1404 search_end = btrfs_super_total_bytes(&info->super_copy);
1405 if (hint_byte) {
1406 block_group = btrfs_lookup_block_group(info, hint_byte);
1407 if (!block_group)
1408 hint_byte = search_start;
1409 block_group = btrfs_find_block_group(root, block_group,
1410 hint_byte, data, 1);
1411 } else {
1412 block_group = btrfs_find_block_group(root,
1413 trans->block_group,
1414 search_start, data, 1);
1415 }
1416
1417 total_needed += empty_size;
1418 path = btrfs_alloc_path();
1419 check_failed:
1420 if (!block_group) {
1421 block_group = btrfs_lookup_block_group(info, search_start);
1422 if (!block_group)
1423 block_group = btrfs_lookup_block_group(info,
1424 orig_search_start);
1425 }
1426 search_start = find_search_start(root, &block_group, search_start,
1427 total_needed, data, full_scan);
1428 search_start = stripe_align(root, search_start);
1429 cached_start = search_start;
1430 btrfs_init_path(path);
1431 ins->objectid = search_start;
1432 ins->offset = 0;
1433 start_found = 0;
1434 path->reada = 2;
1435
1436 ret = btrfs_search_slot(trans, root, ins, path, 0, 0);
1437 if (ret < 0)
1438 goto error;
1439
1440 if (path->slots[0] > 0) {
1441 path->slots[0]--;
1442 }
1443
1444 l = path->nodes[0];
1445 btrfs_item_key_to_cpu(l, &key, path->slots[0]);
1446
1447 /*
1448 * walk backwards to find the first extent item key
1449 */
1450 while(btrfs_key_type(&key) != BTRFS_EXTENT_ITEM_KEY) {
1451 if (path->slots[0] == 0) {
1452 ret = btrfs_prev_leaf(root, path);
1453 if (ret != 0) {
1454 ret = btrfs_search_slot(trans, root, ins,
1455 path, 0, 0);
1456 if (ret < 0)
1457 goto error;
1458 if (path->slots[0] > 0)
1459 path->slots[0]--;
1460 break;
1461 }
1462 } else {
1463 path->slots[0]--;
1464 }
1465 l = path->nodes[0];
1466 btrfs_item_key_to_cpu(l, &key, path->slots[0]);
1467 }
1468 while (1) {
1469 l = path->nodes[0];
1470 slot = path->slots[0];
1471 if (slot >= btrfs_header_nritems(l)) {
1472 ret = btrfs_next_leaf(root, path);
1473 if (ret == 0)
1474 continue;
1475 if (ret < 0)
1476 goto error;
1477
1478 search_start = max(search_start,
1479 block_group->key.objectid);
1480 if (!start_found) {
1481 aligned = stripe_align(root, search_start);
1482 ins->objectid = aligned;
1483 if (aligned >= search_end) {
1484 ret = -ENOSPC;
1485 goto error;
1486 }
1487 ins->offset = search_end - aligned;
1488 start_found = 1;
1489 goto check_pending;
1490 }
1491 ins->objectid = stripe_align(root,
1492 last_byte > search_start ?
1493 last_byte : search_start);
1494 if (search_end <= ins->objectid) {
1495 ret = -ENOSPC;
1496 goto error;
1497 }
1498 ins->offset = search_end - ins->objectid;
1499 BUG_ON(ins->objectid >= search_end);
1500 goto check_pending;
1501 }
1502 btrfs_item_key_to_cpu(l, &key, slot);
1503
1504 if (key.objectid >= search_start && key.objectid > last_byte &&
1505 start_found) {
1506 if (last_byte < search_start)
1507 last_byte = search_start;
1508 aligned = stripe_align(root, last_byte);
1509 hole_size = key.objectid - aligned;
1510 if (key.objectid > aligned && hole_size >= num_bytes) {
1511 ins->objectid = aligned;
1512 ins->offset = hole_size;
1513 goto check_pending;
1514 }
1515 }
1516 if (btrfs_key_type(&key) != BTRFS_EXTENT_ITEM_KEY) {
1517 if (!start_found && btrfs_key_type(&key) ==
1518 BTRFS_BLOCK_GROUP_ITEM_KEY) {
1519 last_byte = key.objectid;
1520 start_found = 1;
1521 }
1522 goto next;
1523 }
1524
1525
1526 start_found = 1;
1527 last_byte = key.objectid + key.offset;
1528
1529 if (!full_scan && data != BTRFS_BLOCK_GROUP_MIXED &&
1530 last_byte >= block_group->key.objectid +
1531 block_group->key.offset) {
1532 btrfs_release_path(root, path);
1533 search_start = block_group->key.objectid +
1534 block_group->key.offset;
1535 goto new_group;
1536 }
1537 next:
1538 path->slots[0]++;
1539 cond_resched();
1540 }
1541 check_pending:
1542 /* we have to make sure we didn't find an extent that has already
1543 * been allocated by the map tree or the original allocation
1544 */
1545 btrfs_release_path(root, path);
1546 BUG_ON(ins->objectid < search_start);
1547
1548 if (ins->objectid + num_bytes >= search_end)
1549 goto enospc;
1550 if (!full_scan && data != BTRFS_BLOCK_GROUP_MIXED &&
1551 ins->objectid + num_bytes > block_group->
1552 key.objectid + block_group->key.offset) {
1553 search_start = block_group->key.objectid +
1554 block_group->key.offset;
1555 goto new_group;
1556 }
1557 if (test_range_bit(&info->extent_ins, ins->objectid,
1558 ins->objectid + num_bytes -1, EXTENT_LOCKED, 0)) {
1559 search_start = ins->objectid + num_bytes;
1560 goto new_group;
1561 }
1562 if (test_range_bit(&info->pinned_extents, ins->objectid,
1563 ins->objectid + num_bytes -1, EXTENT_DIRTY, 0)) {
1564 search_start = ins->objectid + num_bytes;
1565 goto new_group;
1566 }
1567 if (exclude_nr > 0 && (ins->objectid + num_bytes > exclude_start &&
1568 ins->objectid < exclude_start + exclude_nr)) {
1569 search_start = exclude_start + exclude_nr;
1570 goto new_group;
1571 }
1572 if (!data) {
1573 block_group = btrfs_lookup_block_group(info, ins->objectid);
1574 if (block_group)
1575 trans->block_group = block_group;
1576 }
1577 ins->offset = num_bytes;
1578 btrfs_free_path(path);
1579 return 0;
1580
1581 new_group:
1582 if (search_start + num_bytes >= search_end) {
1583 enospc:
1584 search_start = orig_search_start;
1585 if (full_scan) {
1586 ret = -ENOSPC;
1587 goto error;
1588 }
1589 if (wrapped) {
1590 if (!full_scan)
1591 total_needed -= empty_size;
1592 full_scan = 1;
1593 data = BTRFS_BLOCK_GROUP_MIXED;
1594 } else
1595 wrapped = 1;
1596 }
1597 block_group = btrfs_lookup_block_group(info, search_start);
1598 cond_resched();
1599 block_group = btrfs_find_block_group(root, block_group,
1600 search_start, data, 0);
1601 goto check_failed;
1602
1603 error:
1604 btrfs_release_path(root, path);
1605 btrfs_free_path(path);
1606 return ret;
1607 }
1608 /*
1609 * finds a free extent and does all the dirty work required for allocation
1610 * returns the key for the extent through ins, and a tree buffer for
1611 * the first block of the extent through buf.
1612 *
1613 * returns 0 if everything worked, non-zero otherwise.
1614 */
1615 int btrfs_alloc_extent(struct btrfs_trans_handle *trans,
1616 struct btrfs_root *root,
1617 u64 num_bytes, u64 root_objectid, u64 ref_generation,
1618 u64 owner, u64 owner_offset,
1619 u64 empty_size, u64 hint_byte,
1620 u64 search_end, struct btrfs_key *ins, int data)
1621 {
1622 int ret;
1623 int pending_ret;
1624 u64 super_used, root_used;
1625 u64 search_start = 0;
1626 u64 new_hint;
1627 struct btrfs_fs_info *info = root->fs_info;
1628 struct btrfs_root *extent_root = info->extent_root;
1629 struct btrfs_extent_item extent_item;
1630 struct btrfs_path *path;
1631
1632 btrfs_set_stack_extent_refs(&extent_item, 1);
1633 #if 0
1634 new_hint = max(hint_byte, 16ULL * 1024 * 1024 * 1024);
1635 if (new_hint < btrfs_super_total_bytes(&info->super_copy))
1636 hint_byte = new_hint;
1637 #endif
1638 WARN_ON(num_bytes < root->sectorsize);
1639 ret = find_free_extent(trans, root, num_bytes, empty_size,
1640 search_start, search_end, hint_byte, ins,
1641 trans->alloc_exclude_start,
1642 trans->alloc_exclude_nr, data);
1643 BUG_ON(ret);
1644 if (ret)
1645 return ret;
1646
1647 /* block accounting for super block */
1648 super_used = btrfs_super_bytes_used(&info->super_copy);
1649 btrfs_set_super_bytes_used(&info->super_copy, super_used + num_bytes);
1650
1651 /* block accounting for root item */
1652 root_used = btrfs_root_used(&root->root_item);
1653 btrfs_set_root_used(&root->root_item, root_used + num_bytes);
1654
1655 clear_extent_dirty(&root->fs_info->free_space_cache,
1656 ins->objectid, ins->objectid + ins->offset - 1,
1657 GFP_NOFS);
1658
1659 if (root == extent_root) {
1660 set_extent_bits(&root->fs_info->extent_ins, ins->objectid,
1661 ins->objectid + ins->offset - 1,
1662 EXTENT_LOCKED, GFP_NOFS);
1663 WARN_ON(data == 1);
1664 goto update_block;
1665 }
1666
1667 WARN_ON(trans->alloc_exclude_nr);
1668 trans->alloc_exclude_start = ins->objectid;
1669 trans->alloc_exclude_nr = ins->offset;
1670 ret = btrfs_insert_item(trans, extent_root, ins, &extent_item,
1671 sizeof(extent_item));
1672
1673 trans->alloc_exclude_start = 0;
1674 trans->alloc_exclude_nr = 0;
1675 BUG_ON(ret);
1676
1677 path = btrfs_alloc_path();
1678 BUG_ON(!path);
1679 ret = btrfs_insert_extent_backref(trans, extent_root, path,
1680 ins->objectid, root_objectid,
1681 ref_generation, owner, owner_offset);
1682
1683 BUG_ON(ret);
1684 btrfs_free_path(path);
1685 finish_current_insert(trans, extent_root);
1686 pending_ret = del_pending_extents(trans, extent_root);
1687
1688 if (ret) {
1689 return ret;
1690 }
1691 if (pending_ret) {
1692 return pending_ret;
1693 }
1694
1695 update_block:
1696 ret = update_block_group(trans, root, ins->objectid, ins->offset, 1, 0,
1697 data);
1698 BUG_ON(ret);
1699 return 0;
1700 }
1701
1702 /*
1703 * helper function to allocate a block for a given tree
1704 * returns the tree buffer or NULL.
1705 */
1706 struct extent_buffer *btrfs_alloc_free_block(struct btrfs_trans_handle *trans,
1707 struct btrfs_root *root,
1708 u32 blocksize,
1709 u64 root_objectid, u64 hint,
1710 u64 empty_size)
1711 {
1712 u64 ref_generation;
1713
1714 if (root->ref_cows)
1715 ref_generation = trans->transid;
1716 else
1717 ref_generation = 0;
1718
1719
1720 return __btrfs_alloc_free_block(trans, root, blocksize, root_objectid,
1721 ref_generation, 0, 0, hint, empty_size);
1722 }
1723
1724 /*
1725 * helper function to allocate a block for a given tree
1726 * returns the tree buffer or NULL.
1727 */
1728 struct extent_buffer *__btrfs_alloc_free_block(struct btrfs_trans_handle *trans,
1729 struct btrfs_root *root,
1730 u32 blocksize,
1731 u64 root_objectid,
1732 u64 ref_generation,
1733 u64 first_objectid,
1734 int level,
1735 u64 hint,
1736 u64 empty_size)
1737 {
1738 struct btrfs_key ins;
1739 int ret;
1740 struct extent_buffer *buf;
1741
1742 ret = btrfs_alloc_extent(trans, root, blocksize,
1743 root_objectid, ref_generation,
1744 level, first_objectid, empty_size, hint,
1745 (u64)-1, &ins, 0);
1746 if (ret) {
1747 BUG_ON(ret > 0);
1748 return ERR_PTR(ret);
1749 }
1750 buf = btrfs_find_create_tree_block(root, ins.objectid, blocksize);
1751 if (!buf) {
1752 btrfs_free_extent(trans, root, ins.objectid, blocksize,
1753 root->root_key.objectid, ref_generation,
1754 0, 0, 0);
1755 return ERR_PTR(-ENOMEM);
1756 }
1757 btrfs_set_buffer_uptodate(buf);
1758 set_extent_dirty(&trans->transaction->dirty_pages, buf->start,
1759 buf->start + buf->len - 1, GFP_NOFS);
1760 set_extent_bits(&BTRFS_I(root->fs_info->btree_inode)->extent_tree,
1761 buf->start, buf->start + buf->len - 1,
1762 EXTENT_CSUM, GFP_NOFS);
1763 buf->flags |= EXTENT_CSUM;
1764 btrfs_set_buffer_defrag(buf);
1765 trans->blocks_used++;
1766 return buf;
1767 }
1768
1769 static int drop_leaf_ref(struct btrfs_trans_handle *trans,
1770 struct btrfs_root *root, struct extent_buffer *leaf)
1771 {
1772 u64 leaf_owner;
1773 u64 leaf_generation;
1774 struct btrfs_key key;
1775 struct btrfs_file_extent_item *fi;
1776 int i;
1777 int nritems;
1778 int ret;
1779
1780 BUG_ON(!btrfs_is_leaf(leaf));
1781 nritems = btrfs_header_nritems(leaf);
1782 leaf_owner = btrfs_header_owner(leaf);
1783 leaf_generation = btrfs_header_generation(leaf);
1784
1785 for (i = 0; i < nritems; i++) {
1786 u64 disk_bytenr;
1787
1788 btrfs_item_key_to_cpu(leaf, &key, i);
1789 if (btrfs_key_type(&key) != BTRFS_EXTENT_DATA_KEY)
1790 continue;
1791 fi = btrfs_item_ptr(leaf, i, struct btrfs_file_extent_item);
1792 if (btrfs_file_extent_type(leaf, fi) ==
1793 BTRFS_FILE_EXTENT_INLINE)
1794 continue;
1795 /*
1796 * FIXME make sure to insert a trans record that
1797 * repeats the snapshot del on crash
1798 */
1799 disk_bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
1800 if (disk_bytenr == 0)
1801 continue;
1802 ret = btrfs_free_extent(trans, root, disk_bytenr,
1803 btrfs_file_extent_disk_num_bytes(leaf, fi),
1804 leaf_owner, leaf_generation,
1805 key.objectid, key.offset, 0);
1806 BUG_ON(ret);
1807 }
1808 return 0;
1809 }
1810
1811 static void reada_walk_down(struct btrfs_root *root,
1812 struct extent_buffer *node)
1813 {
1814 int i;
1815 u32 nritems;
1816 u64 bytenr;
1817 int ret;
1818 u32 refs;
1819 int level;
1820 u32 blocksize;
1821
1822 nritems = btrfs_header_nritems(node);
1823 level = btrfs_header_level(node);
1824 for (i = 0; i < nritems; i++) {
1825 bytenr = btrfs_node_blockptr(node, i);
1826 blocksize = btrfs_level_size(root, level - 1);
1827 ret = lookup_extent_ref(NULL, root, bytenr, blocksize, &refs);
1828 BUG_ON(ret);
1829 if (refs != 1)
1830 continue;
1831 mutex_unlock(&root->fs_info->fs_mutex);
1832 ret = readahead_tree_block(root, bytenr, blocksize);
1833 cond_resched();
1834 mutex_lock(&root->fs_info->fs_mutex);
1835 if (ret)
1836 break;
1837 }
1838 }
1839
1840 /*
1841 * helper function for drop_snapshot, this walks down the tree dropping ref
1842 * counts as it goes.
1843 */
1844 static int walk_down_tree(struct btrfs_trans_handle *trans, struct btrfs_root
1845 *root, 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 walk_up_tree(struct btrfs_trans_handle *trans, struct btrfs_root
1965 *root, struct btrfs_path *path, int *level)
1966 {
1967 u64 root_owner;
1968 u64 root_gen;
1969 struct btrfs_root_item *root_item = &root->root_item;
1970 int i;
1971 int slot;
1972 int ret;
1973
1974 for(i = *level; i < BTRFS_MAX_LEVEL - 1 && path->nodes[i]; i++) {
1975 slot = path->slots[i];
1976 if (slot < btrfs_header_nritems(path->nodes[i]) - 1) {
1977 struct extent_buffer *node;
1978 struct btrfs_disk_key disk_key;
1979 node = path->nodes[i];
1980 path->slots[i]++;
1981 *level = i;
1982 WARN_ON(*level == 0);
1983 btrfs_node_key(node, &disk_key, path->slots[i]);
1984 memcpy(&root_item->drop_progress,
1985 &disk_key, sizeof(disk_key));
1986 root_item->drop_level = i;
1987 return 0;
1988 } else {
1989 if (path->nodes[*level] == root->node) {
1990 root_owner = root->root_key.objectid;
1991 root_gen =
1992 btrfs_header_generation(path->nodes[*level]);
1993 } else {
1994 struct extent_buffer *node;
1995 node = path->nodes[*level + 1];
1996 root_owner = btrfs_header_owner(node);
1997 root_gen = btrfs_header_generation(node);
1998 }
1999 ret = btrfs_free_extent(trans, root,
2000 path->nodes[*level]->start,
2001 path->nodes[*level]->len,
2002 root_owner, root_gen, 0, 0, 1);
2003 BUG_ON(ret);
2004 free_extent_buffer(path->nodes[*level]);
2005 path->nodes[*level] = NULL;
2006 *level = i + 1;
2007 }
2008 }
2009 return 1;
2010 }
2011
2012 /*
2013 * drop the reference count on the tree rooted at 'snap'. This traverses
2014 * the tree freeing any blocks that have a ref count of zero after being
2015 * decremented.
2016 */
2017 int btrfs_drop_snapshot(struct btrfs_trans_handle *trans, struct btrfs_root
2018 *root)
2019 {
2020 int ret = 0;
2021 int wret;
2022 int level;
2023 struct btrfs_path *path;
2024 int i;
2025 int orig_level;
2026 struct btrfs_root_item *root_item = &root->root_item;
2027
2028 path = btrfs_alloc_path();
2029 BUG_ON(!path);
2030
2031 level = btrfs_header_level(root->node);
2032 orig_level = level;
2033 if (btrfs_disk_key_objectid(&root_item->drop_progress) == 0) {
2034 path->nodes[level] = root->node;
2035 extent_buffer_get(root->node);
2036 path->slots[level] = 0;
2037 } else {
2038 struct btrfs_key key;
2039 struct btrfs_disk_key found_key;
2040 struct extent_buffer *node;
2041
2042 btrfs_disk_key_to_cpu(&key, &root_item->drop_progress);
2043 level = root_item->drop_level;
2044 path->lowest_level = level;
2045 wret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
2046 if (wret < 0) {
2047 ret = wret;
2048 goto out;
2049 }
2050 node = path->nodes[level];
2051 btrfs_node_key(node, &found_key, path->slots[level]);
2052 WARN_ON(memcmp(&found_key, &root_item->drop_progress,
2053 sizeof(found_key)));
2054 }
2055 while(1) {
2056 wret = walk_down_tree(trans, root, path, &level);
2057 if (wret > 0)
2058 break;
2059 if (wret < 0)
2060 ret = wret;
2061
2062 wret = walk_up_tree(trans, root, path, &level);
2063 if (wret > 0)
2064 break;
2065 if (wret < 0)
2066 ret = wret;
2067 ret = -EAGAIN;
2068 break;
2069 }
2070 for (i = 0; i <= orig_level; i++) {
2071 if (path->nodes[i]) {
2072 free_extent_buffer(path->nodes[i]);
2073 path->nodes[i] = NULL;
2074 }
2075 }
2076 out:
2077 btrfs_free_path(path);
2078 return ret;
2079 }
2080
2081 int btrfs_free_block_groups(struct btrfs_fs_info *info)
2082 {
2083 u64 start;
2084 u64 end;
2085 u64 ptr;
2086 int ret;
2087 while(1) {
2088 ret = find_first_extent_bit(&info->block_group_cache, 0,
2089 &start, &end, (unsigned int)-1);
2090 if (ret)
2091 break;
2092 ret = get_state_private(&info->block_group_cache, start, &ptr);
2093 if (!ret)
2094 kfree((void *)(unsigned long)ptr);
2095 clear_extent_bits(&info->block_group_cache, start,
2096 end, (unsigned int)-1, GFP_NOFS);
2097 }
2098 while(1) {
2099 ret = find_first_extent_bit(&info->free_space_cache, 0,
2100 &start, &end, EXTENT_DIRTY);
2101 if (ret)
2102 break;
2103 clear_extent_dirty(&info->free_space_cache, start,
2104 end, GFP_NOFS);
2105 }
2106 return 0;
2107 }
2108
2109 static int relocate_inode_pages(struct inode *inode, u64 start, u64 len)
2110 {
2111 u64 page_start;
2112 u64 page_end;
2113 u64 delalloc_start;
2114 u64 existing_delalloc;
2115 unsigned long last_index;
2116 unsigned long first_index;
2117 unsigned long i;
2118 struct page *page;
2119 struct btrfs_root *root = BTRFS_I(inode)->root;
2120 struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
2121 struct file_ra_state ra;
2122
2123 mutex_lock(&inode->i_mutex);
2124 first_index = start >> PAGE_CACHE_SHIFT;
2125 last_index = (start + len - 1) >> PAGE_CACHE_SHIFT;
2126
2127 memset(&ra, 0, sizeof(ra));
2128 file_ra_state_init(&ra, inode->i_mapping);
2129 btrfs_force_ra(inode->i_mapping, &ra, NULL, first_index, last_index);
2130
2131 for (i = first_index; i <= last_index; i++) {
2132 page = grab_cache_page(inode->i_mapping, i);
2133 if (!page)
2134 goto out_unlock;
2135 if (!PageUptodate(page)) {
2136 btrfs_readpage(NULL, page);
2137 lock_page(page);
2138 if (!PageUptodate(page)) {
2139 unlock_page(page);
2140 page_cache_release(page);
2141 goto out_unlock;
2142 }
2143 }
2144 page_start = (u64)page->index << PAGE_CACHE_SHIFT;
2145 page_end = page_start + PAGE_CACHE_SIZE - 1;
2146
2147 lock_extent(em_tree, page_start, page_end, GFP_NOFS);
2148
2149 delalloc_start = page_start;
2150 existing_delalloc =
2151 count_range_bits(&BTRFS_I(inode)->extent_tree,
2152 &delalloc_start, page_end,
2153 PAGE_CACHE_SIZE, EXTENT_DELALLOC);
2154
2155 set_extent_delalloc(em_tree, page_start,
2156 page_end, GFP_NOFS);
2157
2158 spin_lock(&root->fs_info->delalloc_lock);
2159 root->fs_info->delalloc_bytes += PAGE_CACHE_SIZE -
2160 existing_delalloc;
2161 spin_unlock(&root->fs_info->delalloc_lock);
2162
2163 unlock_extent(em_tree, page_start, page_end, GFP_NOFS);
2164 set_page_dirty(page);
2165 unlock_page(page);
2166 page_cache_release(page);
2167 }
2168
2169 out_unlock:
2170 mutex_unlock(&inode->i_mutex);
2171 return 0;
2172 }
2173
2174 static int relocate_one_reference(struct btrfs_root *extent_root,
2175 struct btrfs_path *path,
2176 struct btrfs_key *extent_key,
2177 u64 ref_root, u64 ref_gen, u64 ref_objectid,
2178 u64 ref_offset)
2179 {
2180 struct inode *inode;
2181 struct btrfs_root *found_root;
2182 struct btrfs_key root_location;
2183 int ret;
2184
2185 root_location.objectid = ref_root;
2186 if (ref_gen == 0)
2187 root_location.offset = 0;
2188 else
2189 root_location.offset = (u64)-1;
2190 root_location.type = BTRFS_ROOT_ITEM_KEY;
2191
2192 found_root = btrfs_read_fs_root_no_name(extent_root->fs_info,
2193 &root_location);
2194 BUG_ON(!found_root);
2195
2196 if (ref_objectid >= BTRFS_FIRST_FREE_OBJECTID) {
2197 mutex_unlock(&extent_root->fs_info->fs_mutex);
2198 inode = btrfs_iget_locked(extent_root->fs_info->sb,
2199 ref_objectid, found_root);
2200 if (inode->i_state & I_NEW) {
2201 /* the inode and parent dir are two different roots */
2202 BTRFS_I(inode)->root = found_root;
2203 BTRFS_I(inode)->location.objectid = ref_objectid;
2204 BTRFS_I(inode)->location.type = BTRFS_INODE_ITEM_KEY;
2205 BTRFS_I(inode)->location.offset = 0;
2206 btrfs_read_locked_inode(inode);
2207 unlock_new_inode(inode);
2208
2209 }
2210 /* this can happen if the reference is not against
2211 * the latest version of the tree root
2212 */
2213 if (is_bad_inode(inode)) {
2214 mutex_lock(&extent_root->fs_info->fs_mutex);
2215 goto out;
2216 }
2217 relocate_inode_pages(inode, ref_offset, extent_key->offset);
2218 /* FIXME, data=ordered will help get rid of this */
2219 filemap_fdatawrite(inode->i_mapping);
2220 iput(inode);
2221 mutex_lock(&extent_root->fs_info->fs_mutex);
2222 } else {
2223 struct btrfs_trans_handle *trans;
2224 struct btrfs_key found_key;
2225 struct extent_buffer *eb;
2226 int level;
2227 int i;
2228
2229 trans = btrfs_start_transaction(found_root, 1);
2230 eb = read_tree_block(found_root, extent_key->objectid,
2231 extent_key->offset);
2232 level = btrfs_header_level(eb);
2233
2234 if (level == 0)
2235 btrfs_item_key_to_cpu(eb, &found_key, 0);
2236 else
2237 btrfs_node_key_to_cpu(eb, &found_key, 0);
2238
2239 free_extent_buffer(eb);
2240
2241 path->lowest_level = level;
2242 path->reada = 0;
2243 ret = btrfs_search_slot(trans, found_root, &found_key, path,
2244 0, 1);
2245 path->lowest_level = 0;
2246 for (i = level; i < BTRFS_MAX_LEVEL; i++) {
2247 if (!path->nodes[i])
2248 break;
2249 free_extent_buffer(path->nodes[i]);
2250 path->nodes[i] = NULL;
2251 }
2252 btrfs_release_path(found_root, path);
2253 btrfs_end_transaction(trans, found_root);
2254 }
2255
2256 out:
2257 return 0;
2258 }
2259
2260 static int relocate_one_extent(struct btrfs_root *extent_root,
2261 struct btrfs_path *path,
2262 struct btrfs_key *extent_key)
2263 {
2264 struct btrfs_key key;
2265 struct btrfs_key found_key;
2266 struct btrfs_extent_ref *ref;
2267 struct extent_buffer *leaf;
2268 u64 ref_root;
2269 u64 ref_gen;
2270 u64 ref_objectid;
2271 u64 ref_offset;
2272 u32 nritems;
2273 u32 item_size;
2274 int ret = 0;
2275
2276 key.objectid = extent_key->objectid;
2277 key.type = BTRFS_EXTENT_REF_KEY;
2278 key.offset = 0;
2279
2280 while(1) {
2281 ret = btrfs_search_slot(NULL, extent_root, &key, path, 0, 0);
2282
2283 BUG_ON(ret == 0);
2284
2285 if (ret < 0)
2286 goto out;
2287
2288 ret = 0;
2289 leaf = path->nodes[0];
2290 nritems = btrfs_header_nritems(leaf);
2291 if (path->slots[0] == nritems)
2292 goto out;
2293
2294 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
2295 if (found_key.objectid != extent_key->objectid)
2296 break;
2297
2298 if (found_key.type != BTRFS_EXTENT_REF_KEY)
2299 break;
2300
2301 key.offset = found_key.offset + 1;
2302 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
2303
2304 ref = btrfs_item_ptr(leaf, path->slots[0],
2305 struct btrfs_extent_ref);
2306 ref_root = btrfs_ref_root(leaf, ref);
2307 ref_gen = btrfs_ref_generation(leaf, ref);
2308 ref_objectid = btrfs_ref_objectid(leaf, ref);
2309 ref_offset = btrfs_ref_offset(leaf, ref);
2310 btrfs_release_path(extent_root, path);
2311
2312 ret = relocate_one_reference(extent_root, path,
2313 extent_key, ref_root, ref_gen,
2314 ref_objectid, ref_offset);
2315 if (ret)
2316 goto out;
2317 }
2318 ret = 0;
2319 out:
2320 btrfs_release_path(extent_root, path);
2321 return ret;
2322 }
2323
2324 static int find_overlapping_extent(struct btrfs_root *root,
2325 struct btrfs_path *path, u64 new_size)
2326 {
2327 struct btrfs_key found_key;
2328 struct extent_buffer *leaf;
2329 int ret;
2330
2331 while(1) {
2332 if (path->slots[0] == 0) {
2333 ret = btrfs_prev_leaf(root, path);
2334 if (ret == 1) {
2335 return 1;
2336 }
2337 if (ret < 0)
2338 return ret;
2339 } else {
2340 path->slots[0]--;
2341 }
2342 leaf = path->nodes[0];
2343 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
2344 if (found_key.type == BTRFS_EXTENT_ITEM_KEY) {
2345 if (found_key.objectid + found_key.offset > new_size)
2346 return 0;
2347 else
2348 return 1;
2349 }
2350 }
2351 return 1;
2352 }
2353
2354 int btrfs_shrink_extent_tree(struct btrfs_root *root, u64 new_size)
2355 {
2356 struct btrfs_trans_handle *trans;
2357 struct btrfs_root *tree_root = root->fs_info->tree_root;
2358 struct btrfs_path *path;
2359 u64 cur_byte;
2360 u64 total_found;
2361 u64 ptr;
2362 struct btrfs_fs_info *info = root->fs_info;
2363 struct extent_map_tree *block_group_cache;
2364 struct btrfs_key key;
2365 struct btrfs_key found_key = { 0, 0, 0 };
2366 struct extent_buffer *leaf;
2367 u32 nritems;
2368 int ret;
2369 int slot;
2370
2371 btrfs_set_super_total_bytes(&info->super_copy, new_size);
2372 block_group_cache = &info->block_group_cache;
2373 path = btrfs_alloc_path();
2374 root = root->fs_info->extent_root;
2375
2376 again:
2377 total_found = 0;
2378 key.objectid = new_size;
2379 cur_byte = key.objectid;
2380 key.offset = 0;
2381 key.type = 0;
2382 while(1) {
2383 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
2384 if (ret < 0)
2385 goto out;
2386 next:
2387 leaf = path->nodes[0];
2388 if (key.objectid == new_size - 1) {
2389 ret = find_overlapping_extent(root, path, new_size);
2390 if (ret != 0) {
2391 btrfs_release_path(root, path);
2392 ret = btrfs_search_slot(NULL, root, &key,
2393 path, 0, 0);
2394 if (ret < 0)
2395 goto out;
2396 }
2397 }
2398 nritems = btrfs_header_nritems(leaf);
2399 ret = 0;
2400 slot = path->slots[0];
2401 if (slot < nritems)
2402 btrfs_item_key_to_cpu(leaf, &found_key, slot);
2403 if (slot == nritems ||
2404 btrfs_key_type(&found_key) != BTRFS_EXTENT_ITEM_KEY) {
2405 path->slots[0]++;
2406 if (path->slots[0] >= nritems) {
2407 ret = btrfs_next_leaf(root, path);
2408 if (ret < 0)
2409 goto out;
2410 if (ret == 1) {
2411 ret = 0;
2412 break;
2413 }
2414 }
2415 goto next;
2416 }
2417 btrfs_item_key_to_cpu(leaf, &found_key, slot);
2418 if (found_key.objectid + found_key.offset <= cur_byte)
2419 continue;
2420 total_found++;
2421 cur_byte = found_key.objectid + found_key.offset;
2422 key.objectid = cur_byte;
2423 btrfs_release_path(root, path);
2424 ret = relocate_one_extent(root, path, &found_key);
2425 }
2426
2427 btrfs_release_path(root, path);
2428
2429 if (total_found > 0) {
2430 trans = btrfs_start_transaction(tree_root, 1);
2431 btrfs_commit_transaction(trans, tree_root);
2432
2433 mutex_unlock(&root->fs_info->fs_mutex);
2434 btrfs_clean_old_snapshots(tree_root);
2435 mutex_lock(&root->fs_info->fs_mutex);
2436
2437 trans = btrfs_start_transaction(tree_root, 1);
2438 btrfs_commit_transaction(trans, tree_root);
2439 goto again;
2440 }
2441
2442 trans = btrfs_start_transaction(root, 1);
2443 key.objectid = new_size;
2444 key.offset = 0;
2445 key.type = 0;
2446 while(1) {
2447 ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
2448 if (ret < 0)
2449 goto out;
2450 bg_next:
2451 leaf = path->nodes[0];
2452 nritems = btrfs_header_nritems(leaf);
2453 ret = 0;
2454 slot = path->slots[0];
2455 if (slot < nritems)
2456 btrfs_item_key_to_cpu(leaf, &found_key, slot);
2457 if (slot == nritems ||
2458 btrfs_key_type(&found_key) != BTRFS_BLOCK_GROUP_ITEM_KEY) {
2459 if (slot < nritems) {
2460 printk("shrinker found key %Lu %u %Lu\n",
2461 found_key.objectid, found_key.type,
2462 found_key.offset);
2463 path->slots[0]++;
2464 }
2465 if (path->slots[0] >= nritems) {
2466 ret = btrfs_next_leaf(root, path);
2467 if (ret < 0)
2468 break;
2469 if (ret == 1) {
2470 ret = 0;
2471 break;
2472 }
2473 }
2474 goto bg_next;
2475 }
2476 btrfs_item_key_to_cpu(leaf, &found_key, slot);
2477 ret = get_state_private(&info->block_group_cache,
2478 found_key.objectid, &ptr);
2479 if (!ret)
2480 kfree((void *)(unsigned long)ptr);
2481
2482 clear_extent_bits(&info->block_group_cache, found_key.objectid,
2483 found_key.objectid + found_key.offset - 1,
2484 (unsigned int)-1, GFP_NOFS);
2485
2486 key.objectid = found_key.objectid + 1;
2487 btrfs_del_item(trans, root, path);
2488 btrfs_release_path(root, path);
2489 }
2490 clear_extent_dirty(&info->free_space_cache, new_size, (u64)-1,
2491 GFP_NOFS);
2492 btrfs_commit_transaction(trans, root);
2493 out:
2494 btrfs_free_path(path);
2495 return ret;
2496 }
2497
2498 int btrfs_grow_extent_tree(struct btrfs_trans_handle *trans,
2499 struct btrfs_root *root, u64 new_size)
2500 {
2501 struct btrfs_path *path;
2502 u64 nr = 0;
2503 u64 cur_byte;
2504 u64 old_size;
2505 struct btrfs_block_group_cache *cache;
2506 struct btrfs_block_group_item *item;
2507 struct btrfs_fs_info *info = root->fs_info;
2508 struct extent_map_tree *block_group_cache;
2509 struct btrfs_key key;
2510 struct extent_buffer *leaf;
2511 int ret;
2512 int bit;
2513
2514 old_size = btrfs_super_total_bytes(&info->super_copy);
2515 block_group_cache = &info->block_group_cache;
2516
2517 root = info->extent_root;
2518
2519 cache = btrfs_lookup_block_group(root->fs_info, old_size - 1);
2520
2521 cur_byte = cache->key.objectid + cache->key.offset;
2522 if (cur_byte >= new_size)
2523 goto set_size;
2524
2525 key.offset = BTRFS_BLOCK_GROUP_SIZE;
2526 btrfs_set_key_type(&key, BTRFS_BLOCK_GROUP_ITEM_KEY);
2527
2528 path = btrfs_alloc_path();
2529 if (!path)
2530 return -ENOMEM;
2531
2532 while(cur_byte < new_size) {
2533 key.objectid = cur_byte;
2534 ret = btrfs_insert_empty_item(trans, root, path, &key,
2535 sizeof(struct btrfs_block_group_item));
2536 BUG_ON(ret);
2537 leaf = path->nodes[0];
2538 item = btrfs_item_ptr(leaf, path->slots[0],
2539 struct btrfs_block_group_item);
2540
2541 btrfs_set_disk_block_group_used(leaf, item, 0);
2542 if (nr % 3) {
2543 btrfs_set_disk_block_group_flags(leaf, item,
2544 BTRFS_BLOCK_GROUP_DATA);
2545 } else {
2546 btrfs_set_disk_block_group_flags(leaf, item, 0);
2547 }
2548 nr++;
2549
2550 cache = kmalloc(sizeof(*cache), GFP_NOFS);
2551 BUG_ON(!cache);
2552
2553 read_extent_buffer(leaf, &cache->item, (unsigned long)item,
2554 sizeof(cache->item));
2555
2556 memcpy(&cache->key, &key, sizeof(key));
2557 cache->cached = 0;
2558 cache->pinned = 0;
2559 cur_byte = key.objectid + key.offset;
2560 btrfs_release_path(root, path);
2561
2562 if (cache->item.flags & BTRFS_BLOCK_GROUP_DATA) {
2563 bit = BLOCK_GROUP_DATA;
2564 cache->data = BTRFS_BLOCK_GROUP_DATA;
2565 } else {
2566 bit = BLOCK_GROUP_METADATA;
2567 cache->data = 0;
2568 }
2569
2570 /* use EXTENT_LOCKED to prevent merging */
2571 set_extent_bits(block_group_cache, key.objectid,
2572 key.objectid + key.offset - 1,
2573 bit | EXTENT_LOCKED, GFP_NOFS);
2574 set_state_private(block_group_cache, key.objectid,
2575 (unsigned long)cache);
2576 }
2577 btrfs_free_path(path);
2578 set_size:
2579 btrfs_set_super_total_bytes(&info->super_copy, new_size);
2580 return 0;
2581 }
2582
2583 int btrfs_read_block_groups(struct btrfs_root *root)
2584 {
2585 struct btrfs_path *path;
2586 int ret;
2587 int err = 0;
2588 int bit;
2589 struct btrfs_block_group_cache *cache;
2590 struct btrfs_fs_info *info = root->fs_info;
2591 struct extent_map_tree *block_group_cache;
2592 struct btrfs_key key;
2593 struct btrfs_key found_key;
2594 struct extent_buffer *leaf;
2595
2596 block_group_cache = &info->block_group_cache;
2597
2598 root = info->extent_root;
2599 key.objectid = 0;
2600 key.offset = BTRFS_BLOCK_GROUP_SIZE;
2601 btrfs_set_key_type(&key, BTRFS_BLOCK_GROUP_ITEM_KEY);
2602
2603 path = btrfs_alloc_path();
2604 if (!path)
2605 return -ENOMEM;
2606
2607 while(1) {
2608 ret = btrfs_search_slot(NULL, info->extent_root,
2609 &key, path, 0, 0);
2610 if (ret != 0) {
2611 err = ret;
2612 break;
2613 }
2614 leaf = path->nodes[0];
2615 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
2616 cache = kmalloc(sizeof(*cache), GFP_NOFS);
2617 if (!cache) {
2618 err = -1;
2619 break;
2620 }
2621
2622 read_extent_buffer(leaf, &cache->item,
2623 btrfs_item_ptr_offset(leaf, path->slots[0]),
2624 sizeof(cache->item));
2625 memcpy(&cache->key, &found_key, sizeof(found_key));
2626 cache->cached = 0;
2627 cache->pinned = 0;
2628 key.objectid = found_key.objectid + found_key.offset;
2629 btrfs_release_path(root, path);
2630
2631 if (cache->item.flags & BTRFS_BLOCK_GROUP_MIXED) {
2632 bit = BLOCK_GROUP_DATA | BLOCK_GROUP_METADATA;
2633 cache->data = BTRFS_BLOCK_GROUP_MIXED;
2634 } else if (cache->item.flags & BTRFS_BLOCK_GROUP_DATA) {
2635 bit = BLOCK_GROUP_DATA;
2636 cache->data = BTRFS_BLOCK_GROUP_DATA;
2637 } else {
2638 bit = BLOCK_GROUP_METADATA;
2639 cache->data = 0;
2640 }
2641
2642 /* use EXTENT_LOCKED to prevent merging */
2643 set_extent_bits(block_group_cache, found_key.objectid,
2644 found_key.objectid + found_key.offset - 1,
2645 bit | EXTENT_LOCKED, GFP_NOFS);
2646 set_state_private(block_group_cache, found_key.objectid,
2647 (unsigned long)cache);
2648
2649 if (key.objectid >=
2650 btrfs_super_total_bytes(&info->super_copy))
2651 break;
2652 }
2653
2654 btrfs_free_path(path);
2655 return 0;
2656 }
Linux kernel - Deliverables
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