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page allocator: do not setup zonelist cache when there is only one node
[linux/fpc-iii.git] / fs / btrfs / relocation.c
blobb23dc209ae103192bf4eea8ab6ca70f27adda11e
1 /*
2 * Copyright (C) 2009 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/pagemap.h>
21 #include <linux/writeback.h>
22 #include <linux/blkdev.h>
23 #include <linux/rbtree.h>
24 #include "ctree.h"
25 #include "disk-io.h"
26 #include "transaction.h"
27 #include "volumes.h"
28 #include "locking.h"
29 #include "btrfs_inode.h"
30 #include "async-thread.h"
31
32 /*
33 * backref_node, mapping_node and tree_block start with this
34 */
35 struct tree_entry {
36 struct rb_node rb_node;
37 u64 bytenr;
38 };
39
40 /*
41 * present a tree block in the backref cache
42 */
43 struct backref_node {
44 struct rb_node rb_node;
45 u64 bytenr;
46 /* objectid tree block owner */
47 u64 owner;
48 /* list of upper level blocks reference this block */
49 struct list_head upper;
50 /* list of child blocks in the cache */
51 struct list_head lower;
52 /* NULL if this node is not tree root */
53 struct btrfs_root *root;
54 /* extent buffer got by COW the block */
55 struct extent_buffer *eb;
56 /* level of tree block */
57 unsigned int level:8;
58 /* 1 if the block is root of old snapshot */
59 unsigned int old_root:1;
60 /* 1 if no child blocks in the cache */
61 unsigned int lowest:1;
62 /* is the extent buffer locked */
63 unsigned int locked:1;
64 /* has the block been processed */
65 unsigned int processed:1;
66 /* have backrefs of this block been checked */
67 unsigned int checked:1;
68 };
69
70 /*
71 * present a block pointer in the backref cache
72 */
73 struct backref_edge {
74 struct list_head list[2];
75 struct backref_node *node[2];
76 u64 blockptr;
77 };
78
79 #define LOWER 0
80 #define UPPER 1
81
82 struct backref_cache {
83 /* red black tree of all backref nodes in the cache */
84 struct rb_root rb_root;
85 /* list of backref nodes with no child block in the cache */
86 struct list_head pending[BTRFS_MAX_LEVEL];
87 spinlock_t lock;
88 };
89
90 /*
91 * map address of tree root to tree
92 */
93 struct mapping_node {
94 struct rb_node rb_node;
95 u64 bytenr;
96 void *data;
97 };
98
99 struct mapping_tree {
100 struct rb_root rb_root;
101 spinlock_t lock;
102 };
103
104 /*
105 * present a tree block to process
106 */
107 struct tree_block {
108 struct rb_node rb_node;
109 u64 bytenr;
110 struct btrfs_key key;
111 unsigned int level:8;
112 unsigned int key_ready:1;
113 };
114
115 /* inode vector */
116 #define INODEVEC_SIZE 16
117
118 struct inodevec {
119 struct list_head list;
120 struct inode *inode[INODEVEC_SIZE];
121 int nr;
122 };
123
124 struct reloc_control {
125 /* block group to relocate */
126 struct btrfs_block_group_cache *block_group;
127 /* extent tree */
128 struct btrfs_root *extent_root;
129 /* inode for moving data */
130 struct inode *data_inode;
131 struct btrfs_workers workers;
132 /* tree blocks have been processed */
133 struct extent_io_tree processed_blocks;
134 /* map start of tree root to corresponding reloc tree */
135 struct mapping_tree reloc_root_tree;
136 /* list of reloc trees */
137 struct list_head reloc_roots;
138 u64 search_start;
139 u64 extents_found;
140 u64 extents_skipped;
141 int stage;
142 int create_reloc_root;
143 unsigned int found_file_extent:1;
144 unsigned int found_old_snapshot:1;
145 };
146
147 /* stages of data relocation */
148 #define MOVE_DATA_EXTENTS 0
149 #define UPDATE_DATA_PTRS 1
150
151 /*
152 * merge reloc tree to corresponding fs tree in worker threads
153 */
154 struct async_merge {
155 struct btrfs_work work;
156 struct reloc_control *rc;
157 struct btrfs_root *root;
158 struct completion *done;
159 atomic_t *num_pending;
160 };
161
162 static void mapping_tree_init(struct mapping_tree *tree)
163 {
164 tree->rb_root.rb_node = NULL;
165 spin_lock_init(&tree->lock);
166 }
167
168 static void backref_cache_init(struct backref_cache *cache)
169 {
170 int i;
171 cache->rb_root.rb_node = NULL;
172 for (i = 0; i < BTRFS_MAX_LEVEL; i++)
173 INIT_LIST_HEAD(&cache->pending[i]);
174 spin_lock_init(&cache->lock);
175 }
176
177 static void backref_node_init(struct backref_node *node)
178 {
179 memset(node, 0, sizeof(*node));
180 INIT_LIST_HEAD(&node->upper);
181 INIT_LIST_HEAD(&node->lower);
182 RB_CLEAR_NODE(&node->rb_node);
183 }
184
185 static struct rb_node *tree_insert(struct rb_root *root, u64 bytenr,
186 struct rb_node *node)
187 {
188 struct rb_node **p = &root->rb_node;
189 struct rb_node *parent = NULL;
190 struct tree_entry *entry;
191
192 while (*p) {
193 parent = *p;
194 entry = rb_entry(parent, struct tree_entry, rb_node);
195
196 if (bytenr < entry->bytenr)
197 p = &(*p)->rb_left;
198 else if (bytenr > entry->bytenr)
199 p = &(*p)->rb_right;
200 else
201 return parent;
202 }
203
204 rb_link_node(node, parent, p);
205 rb_insert_color(node, root);
206 return NULL;
207 }
208
209 static struct rb_node *tree_search(struct rb_root *root, u64 bytenr)
210 {
211 struct rb_node *n = root->rb_node;
212 struct tree_entry *entry;
213
214 while (n) {
215 entry = rb_entry(n, struct tree_entry, rb_node);
216
217 if (bytenr < entry->bytenr)
218 n = n->rb_left;
219 else if (bytenr > entry->bytenr)
220 n = n->rb_right;
221 else
222 return n;
223 }
224 return NULL;
225 }
226
227 /*
228 * walk up backref nodes until reach node presents tree root
229 */
230 static struct backref_node *walk_up_backref(struct backref_node *node,
231 struct backref_edge *edges[],
232 int *index)
233 {
234 struct backref_edge *edge;
235 int idx = *index;
236
237 while (!list_empty(&node->upper)) {
238 edge = list_entry(node->upper.next,
239 struct backref_edge, list[LOWER]);
240 edges[idx++] = edge;
241 node = edge->node[UPPER];
242 }
243 *index = idx;
244 return node;
245 }
246
247 /*
248 * walk down backref nodes to find start of next reference path
249 */
250 static struct backref_node *walk_down_backref(struct backref_edge *edges[],
251 int *index)
252 {
253 struct backref_edge *edge;
254 struct backref_node *lower;
255 int idx = *index;
256
257 while (idx > 0) {
258 edge = edges[idx - 1];
259 lower = edge->node[LOWER];
260 if (list_is_last(&edge->list[LOWER], &lower->upper)) {
261 idx--;
262 continue;
263 }
264 edge = list_entry(edge->list[LOWER].next,
265 struct backref_edge, list[LOWER]);
266 edges[idx - 1] = edge;
267 *index = idx;
268 return edge->node[UPPER];
269 }
270 *index = 0;
271 return NULL;
272 }
273
274 static void drop_node_buffer(struct backref_node *node)
275 {
276 if (node->eb) {
277 if (node->locked) {
278 btrfs_tree_unlock(node->eb);
279 node->locked = 0;
280 }
281 free_extent_buffer(node->eb);
282 node->eb = NULL;
283 }
284 }
285
286 static void drop_backref_node(struct backref_cache *tree,
287 struct backref_node *node)
288 {
289 BUG_ON(!node->lowest);
290 BUG_ON(!list_empty(&node->upper));
291
292 drop_node_buffer(node);
293 list_del(&node->lower);
294
295 rb_erase(&node->rb_node, &tree->rb_root);
296 kfree(node);
297 }
298
299 /*
300 * remove a backref node from the backref cache
301 */
302 static void remove_backref_node(struct backref_cache *cache,
303 struct backref_node *node)
304 {
305 struct backref_node *upper;
306 struct backref_edge *edge;
307
308 if (!node)
309 return;
310
311 BUG_ON(!node->lowest);
312 while (!list_empty(&node->upper)) {
313 edge = list_entry(node->upper.next, struct backref_edge,
314 list[LOWER]);
315 upper = edge->node[UPPER];
316 list_del(&edge->list[LOWER]);
317 list_del(&edge->list[UPPER]);
318 kfree(edge);
319 /*
320 * add the node to pending list if no other
321 * child block cached.
322 */
323 if (list_empty(&upper->lower)) {
324 list_add_tail(&upper->lower,
325 &cache->pending[upper->level]);
326 upper->lowest = 1;
327 }
328 }
329 drop_backref_node(cache, node);
330 }
331
332 /*
333 * find reloc tree by address of tree root
334 */
335 static struct btrfs_root *find_reloc_root(struct reloc_control *rc,
336 u64 bytenr)
337 {
338 struct rb_node *rb_node;
339 struct mapping_node *node;
340 struct btrfs_root *root = NULL;
341
342 spin_lock(&rc->reloc_root_tree.lock);
343 rb_node = tree_search(&rc->reloc_root_tree.rb_root, bytenr);
344 if (rb_node) {
345 node = rb_entry(rb_node, struct mapping_node, rb_node);
346 root = (struct btrfs_root *)node->data;
347 }
348 spin_unlock(&rc->reloc_root_tree.lock);
349 return root;
350 }
351
352 static int is_cowonly_root(u64 root_objectid)
353 {
354 if (root_objectid == BTRFS_ROOT_TREE_OBJECTID ||
355 root_objectid == BTRFS_EXTENT_TREE_OBJECTID ||
356 root_objectid == BTRFS_CHUNK_TREE_OBJECTID ||
357 root_objectid == BTRFS_DEV_TREE_OBJECTID ||
358 root_objectid == BTRFS_TREE_LOG_OBJECTID ||
359 root_objectid == BTRFS_CSUM_TREE_OBJECTID)
360 return 1;
361 return 0;
362 }
363
364 static struct btrfs_root *read_fs_root(struct btrfs_fs_info *fs_info,
365 u64 root_objectid)
366 {
367 struct btrfs_key key;
368
369 key.objectid = root_objectid;
370 key.type = BTRFS_ROOT_ITEM_KEY;
371 if (is_cowonly_root(root_objectid))
372 key.offset = 0;
373 else
374 key.offset = (u64)-1;
375
376 return btrfs_read_fs_root_no_name(fs_info, &key);
377 }
378
379 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
380 static noinline_for_stack
381 struct btrfs_root *find_tree_root(struct reloc_control *rc,
382 struct extent_buffer *leaf,
383 struct btrfs_extent_ref_v0 *ref0)
384 {
385 struct btrfs_root *root;
386 u64 root_objectid = btrfs_ref_root_v0(leaf, ref0);
387 u64 generation = btrfs_ref_generation_v0(leaf, ref0);
388
389 BUG_ON(root_objectid == BTRFS_TREE_RELOC_OBJECTID);
390
391 root = read_fs_root(rc->extent_root->fs_info, root_objectid);
392 BUG_ON(IS_ERR(root));
393
394 if (root->ref_cows &&
395 generation != btrfs_root_generation(&root->root_item))
396 return NULL;
397
398 return root;
399 }
400 #endif
401
402 static noinline_for_stack
403 int find_inline_backref(struct extent_buffer *leaf, int slot,
404 unsigned long *ptr, unsigned long *end)
405 {
406 struct btrfs_extent_item *ei;
407 struct btrfs_tree_block_info *bi;
408 u32 item_size;
409
410 item_size = btrfs_item_size_nr(leaf, slot);
411 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
412 if (item_size < sizeof(*ei)) {
413 WARN_ON(item_size != sizeof(struct btrfs_extent_item_v0));
414 return 1;
415 }
416 #endif
417 ei = btrfs_item_ptr(leaf, slot, struct btrfs_extent_item);
418 WARN_ON(!(btrfs_extent_flags(leaf, ei) &
419 BTRFS_EXTENT_FLAG_TREE_BLOCK));
420
421 if (item_size <= sizeof(*ei) + sizeof(*bi)) {
422 WARN_ON(item_size < sizeof(*ei) + sizeof(*bi));
423 return 1;
424 }
425
426 bi = (struct btrfs_tree_block_info *)(ei + 1);
427 *ptr = (unsigned long)(bi + 1);
428 *end = (unsigned long)ei + item_size;
429 return 0;
430 }
431
432 /*
433 * build backref tree for a given tree block. root of the backref tree
434 * corresponds the tree block, leaves of the backref tree correspond
435 * roots of b-trees that reference the tree block.
436 *
437 * the basic idea of this function is check backrefs of a given block
438 * to find upper level blocks that refernece the block, and then check
439 * bakcrefs of these upper level blocks recursively. the recursion stop
440 * when tree root is reached or backrefs for the block is cached.
441 *
442 * NOTE: if we find backrefs for a block are cached, we know backrefs
443 * for all upper level blocks that directly/indirectly reference the
444 * block are also cached.
445 */
446 static struct backref_node *build_backref_tree(struct reloc_control *rc,
447 struct backref_cache *cache,
448 struct btrfs_key *node_key,
449 int level, u64 bytenr)
450 {
451 struct btrfs_path *path1;
452 struct btrfs_path *path2;
453 struct extent_buffer *eb;
454 struct btrfs_root *root;
455 struct backref_node *cur;
456 struct backref_node *upper;
457 struct backref_node *lower;
458 struct backref_node *node = NULL;
459 struct backref_node *exist = NULL;
460 struct backref_edge *edge;
461 struct rb_node *rb_node;
462 struct btrfs_key key;
463 unsigned long end;
464 unsigned long ptr;
465 LIST_HEAD(list);
466 int ret;
467 int err = 0;
468
469 path1 = btrfs_alloc_path();
470 path2 = btrfs_alloc_path();
471 if (!path1 || !path2) {
472 err = -ENOMEM;
473 goto out;
474 }
475
476 node = kmalloc(sizeof(*node), GFP_NOFS);
477 if (!node) {
478 err = -ENOMEM;
479 goto out;
480 }
481
482 backref_node_init(node);
483 node->bytenr = bytenr;
484 node->owner = 0;
485 node->level = level;
486 node->lowest = 1;
487 cur = node;
488 again:
489 end = 0;
490 ptr = 0;
491 key.objectid = cur->bytenr;
492 key.type = BTRFS_EXTENT_ITEM_KEY;
493 key.offset = (u64)-1;
494
495 path1->search_commit_root = 1;
496 path1->skip_locking = 1;
497 ret = btrfs_search_slot(NULL, rc->extent_root, &key, path1,
498 0, 0);
499 if (ret < 0) {
500 err = ret;
501 goto out;
502 }
503 BUG_ON(!ret || !path1->slots[0]);
504
505 path1->slots[0]--;
506
507 WARN_ON(cur->checked);
508 if (!list_empty(&cur->upper)) {
509 /*
510 * the backref was added previously when processsing
511 * backref of type BTRFS_TREE_BLOCK_REF_KEY
512 */
513 BUG_ON(!list_is_singular(&cur->upper));
514 edge = list_entry(cur->upper.next, struct backref_edge,
515 list[LOWER]);
516 BUG_ON(!list_empty(&edge->list[UPPER]));
517 exist = edge->node[UPPER];
518 /*
519 * add the upper level block to pending list if we need
520 * check its backrefs
521 */
522 if (!exist->checked)
523 list_add_tail(&edge->list[UPPER], &list);
524 } else {
525 exist = NULL;
526 }
527
528 while (1) {
529 cond_resched();
530 eb = path1->nodes[0];
531
532 if (ptr >= end) {
533 if (path1->slots[0] >= btrfs_header_nritems(eb)) {
534 ret = btrfs_next_leaf(rc->extent_root, path1);
535 if (ret < 0) {
536 err = ret;
537 goto out;
538 }
539 if (ret > 0)
540 break;
541 eb = path1->nodes[0];
542 }
543
544 btrfs_item_key_to_cpu(eb, &key, path1->slots[0]);
545 if (key.objectid != cur->bytenr) {
546 WARN_ON(exist);
547 break;
548 }
549
550 if (key.type == BTRFS_EXTENT_ITEM_KEY) {
551 ret = find_inline_backref(eb, path1->slots[0],
552 &ptr, &end);
553 if (ret)
554 goto next;
555 }
556 }
557
558 if (ptr < end) {
559 /* update key for inline back ref */
560 struct btrfs_extent_inline_ref *iref;
561 iref = (struct btrfs_extent_inline_ref *)ptr;
562 key.type = btrfs_extent_inline_ref_type(eb, iref);
563 key.offset = btrfs_extent_inline_ref_offset(eb, iref);
564 WARN_ON(key.type != BTRFS_TREE_BLOCK_REF_KEY &&
565 key.type != BTRFS_SHARED_BLOCK_REF_KEY);
566 }
567
568 if (exist &&
569 ((key.type == BTRFS_TREE_BLOCK_REF_KEY &&
570 exist->owner == key.offset) ||
571 (key.type == BTRFS_SHARED_BLOCK_REF_KEY &&
572 exist->bytenr == key.offset))) {
573 exist = NULL;
574 goto next;
575 }
576
577 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
578 if (key.type == BTRFS_SHARED_BLOCK_REF_KEY ||
579 key.type == BTRFS_EXTENT_REF_V0_KEY) {
580 if (key.objectid == key.offset &&
581 key.type == BTRFS_EXTENT_REF_V0_KEY) {
582 struct btrfs_extent_ref_v0 *ref0;
583 ref0 = btrfs_item_ptr(eb, path1->slots[0],
584 struct btrfs_extent_ref_v0);
585 root = find_tree_root(rc, eb, ref0);
586 if (root)
587 cur->root = root;
588 else
589 cur->old_root = 1;
590 break;
591 }
592 #else
593 BUG_ON(key.type == BTRFS_EXTENT_REF_V0_KEY);
594 if (key.type == BTRFS_SHARED_BLOCK_REF_KEY) {
595 #endif
596 if (key.objectid == key.offset) {
597 /*
598 * only root blocks of reloc trees use
599 * backref of this type.
600 */
601 root = find_reloc_root(rc, cur->bytenr);
602 BUG_ON(!root);
603 cur->root = root;
604 break;
605 }
606
607 edge = kzalloc(sizeof(*edge), GFP_NOFS);
608 if (!edge) {
609 err = -ENOMEM;
610 goto out;
611 }
612 rb_node = tree_search(&cache->rb_root, key.offset);
613 if (!rb_node) {
614 upper = kmalloc(sizeof(*upper), GFP_NOFS);
615 if (!upper) {
616 kfree(edge);
617 err = -ENOMEM;
618 goto out;
619 }
620 backref_node_init(upper);
621 upper->bytenr = key.offset;
622 upper->owner = 0;
623 upper->level = cur->level + 1;
624 /*
625 * backrefs for the upper level block isn't
626 * cached, add the block to pending list
627 */
628 list_add_tail(&edge->list[UPPER], &list);
629 } else {
630 upper = rb_entry(rb_node, struct backref_node,
631 rb_node);
632 INIT_LIST_HEAD(&edge->list[UPPER]);
633 }
634 list_add(&edge->list[LOWER], &cur->upper);
635 edge->node[UPPER] = upper;
636 edge->node[LOWER] = cur;
637
638 goto next;
639 } else if (key.type != BTRFS_TREE_BLOCK_REF_KEY) {
640 goto next;
641 }
642
643 /* key.type == BTRFS_TREE_BLOCK_REF_KEY */
644 root = read_fs_root(rc->extent_root->fs_info, key.offset);
645 if (IS_ERR(root)) {
646 err = PTR_ERR(root);
647 goto out;
648 }
649
650 if (btrfs_root_level(&root->root_item) == cur->level) {
651 /* tree root */
652 BUG_ON(btrfs_root_bytenr(&root->root_item) !=
653 cur->bytenr);
654 cur->root = root;
655 break;
656 }
657
658 level = cur->level + 1;
659
660 /*
661 * searching the tree to find upper level blocks
662 * reference the block.
663 */
664 path2->search_commit_root = 1;
665 path2->skip_locking = 1;
666 path2->lowest_level = level;
667 ret = btrfs_search_slot(NULL, root, node_key, path2, 0, 0);
668 path2->lowest_level = 0;
669 if (ret < 0) {
670 err = ret;
671 goto out;
672 }
673
674 eb = path2->nodes[level];
675 WARN_ON(btrfs_node_blockptr(eb, path2->slots[level]) !=
676 cur->bytenr);
677
678 lower = cur;
679 for (; level < BTRFS_MAX_LEVEL; level++) {
680 if (!path2->nodes[level]) {
681 BUG_ON(btrfs_root_bytenr(&root->root_item) !=
682 lower->bytenr);
683 lower->root = root;
684 break;
685 }
686
687 edge = kzalloc(sizeof(*edge), GFP_NOFS);
688 if (!edge) {
689 err = -ENOMEM;
690 goto out;
691 }
692
693 eb = path2->nodes[level];
694 rb_node = tree_search(&cache->rb_root, eb->start);
695 if (!rb_node) {
696 upper = kmalloc(sizeof(*upper), GFP_NOFS);
697 if (!upper) {
698 kfree(edge);
699 err = -ENOMEM;
700 goto out;
701 }
702 backref_node_init(upper);
703 upper->bytenr = eb->start;
704 upper->owner = btrfs_header_owner(eb);
705 upper->level = lower->level + 1;
706
707 /*
708 * if we know the block isn't shared
709 * we can void checking its backrefs.
710 */
711 if (btrfs_block_can_be_shared(root, eb))
712 upper->checked = 0;
713 else
714 upper->checked = 1;
715
716 /*
717 * add the block to pending list if we
718 * need check its backrefs. only block
719 * at 'cur->level + 1' is added to the
720 * tail of pending list. this guarantees
721 * we check backrefs from lower level
722 * blocks to upper level blocks.
723 */
724 if (!upper->checked &&
725 level == cur->level + 1) {
726 list_add_tail(&edge->list[UPPER],
727 &list);
728 } else
729 INIT_LIST_HEAD(&edge->list[UPPER]);
730 } else {
731 upper = rb_entry(rb_node, struct backref_node,
732 rb_node);
733 BUG_ON(!upper->checked);
734 INIT_LIST_HEAD(&edge->list[UPPER]);
735 }
736 list_add_tail(&edge->list[LOWER], &lower->upper);
737 edge->node[UPPER] = upper;
738 edge->node[LOWER] = lower;
739
740 if (rb_node)
741 break;
742 lower = upper;
743 upper = NULL;
744 }
745 btrfs_release_path(root, path2);
746 next:
747 if (ptr < end) {
748 ptr += btrfs_extent_inline_ref_size(key.type);
749 if (ptr >= end) {
750 WARN_ON(ptr > end);
751 ptr = 0;
752 end = 0;
753 }
754 }
755 if (ptr >= end)
756 path1->slots[0]++;
757 }
758 btrfs_release_path(rc->extent_root, path1);
759
760 cur->checked = 1;
761 WARN_ON(exist);
762
763 /* the pending list isn't empty, take the first block to process */
764 if (!list_empty(&list)) {
765 edge = list_entry(list.next, struct backref_edge, list[UPPER]);
766 list_del_init(&edge->list[UPPER]);
767 cur = edge->node[UPPER];
768 goto again;
769 }
770
771 /*
772 * everything goes well, connect backref nodes and insert backref nodes
773 * into the cache.
774 */
775 BUG_ON(!node->checked);
776 rb_node = tree_insert(&cache->rb_root, node->bytenr, &node->rb_node);
777 BUG_ON(rb_node);
778
779 list_for_each_entry(edge, &node->upper, list[LOWER])
780 list_add_tail(&edge->list[UPPER], &list);
781
782 while (!list_empty(&list)) {
783 edge = list_entry(list.next, struct backref_edge, list[UPPER]);
784 list_del_init(&edge->list[UPPER]);
785 upper = edge->node[UPPER];
786
787 if (!RB_EMPTY_NODE(&upper->rb_node)) {
788 if (upper->lowest) {
789 list_del_init(&upper->lower);
790 upper->lowest = 0;
791 }
792
793 list_add_tail(&edge->list[UPPER], &upper->lower);
794 continue;
795 }
796
797 BUG_ON(!upper->checked);
798 rb_node = tree_insert(&cache->rb_root, upper->bytenr,
799 &upper->rb_node);
800 BUG_ON(rb_node);
801
802 list_add_tail(&edge->list[UPPER], &upper->lower);
803
804 list_for_each_entry(edge, &upper->upper, list[LOWER])
805 list_add_tail(&edge->list[UPPER], &list);
806 }
807 out:
808 btrfs_free_path(path1);
809 btrfs_free_path(path2);
810 if (err) {
811 INIT_LIST_HEAD(&list);
812 upper = node;
813 while (upper) {
814 if (RB_EMPTY_NODE(&upper->rb_node)) {
815 list_splice_tail(&upper->upper, &list);
816 kfree(upper);
817 }
818
819 if (list_empty(&list))
820 break;
821
822 edge = list_entry(list.next, struct backref_edge,
823 list[LOWER]);
824 upper = edge->node[UPPER];
825 kfree(edge);
826 }
827 return ERR_PTR(err);
828 }
829 return node;
830 }
831
832 /*
833 * helper to add 'address of tree root -> reloc tree' mapping
834 */
835 static int __add_reloc_root(struct btrfs_root *root)
836 {
837 struct rb_node *rb_node;
838 struct mapping_node *node;
839 struct reloc_control *rc = root->fs_info->reloc_ctl;
840
841 node = kmalloc(sizeof(*node), GFP_NOFS);
842 BUG_ON(!node);
843
844 node->bytenr = root->node->start;
845 node->data = root;
846
847 spin_lock(&rc->reloc_root_tree.lock);
848 rb_node = tree_insert(&rc->reloc_root_tree.rb_root,
849 node->bytenr, &node->rb_node);
850 spin_unlock(&rc->reloc_root_tree.lock);
851 BUG_ON(rb_node);
852
853 list_add_tail(&root->root_list, &rc->reloc_roots);
854 return 0;
855 }
856
857 /*
858 * helper to update/delete the 'address of tree root -> reloc tree'
859 * mapping
860 */
861 static int __update_reloc_root(struct btrfs_root *root, int del)
862 {
863 struct rb_node *rb_node;
864 struct mapping_node *node = NULL;
865 struct reloc_control *rc = root->fs_info->reloc_ctl;
866
867 spin_lock(&rc->reloc_root_tree.lock);
868 rb_node = tree_search(&rc->reloc_root_tree.rb_root,
869 root->commit_root->start);
870 if (rb_node) {
871 node = rb_entry(rb_node, struct mapping_node, rb_node);
872 rb_erase(&node->rb_node, &rc->reloc_root_tree.rb_root);
873 }
874 spin_unlock(&rc->reloc_root_tree.lock);
875
876 BUG_ON((struct btrfs_root *)node->data != root);
877
878 if (!del) {
879 spin_lock(&rc->reloc_root_tree.lock);
880 node->bytenr = root->node->start;
881 rb_node = tree_insert(&rc->reloc_root_tree.rb_root,
882 node->bytenr, &node->rb_node);
883 spin_unlock(&rc->reloc_root_tree.lock);
884 BUG_ON(rb_node);
885 } else {
886 list_del_init(&root->root_list);
887 kfree(node);
888 }
889 return 0;
890 }
891
892 /*
893 * create reloc tree for a given fs tree. reloc tree is just a
894 * snapshot of the fs tree with special root objectid.
895 */
896 int btrfs_init_reloc_root(struct btrfs_trans_handle *trans,
897 struct btrfs_root *root)
898 {
899 struct btrfs_root *reloc_root;
900 struct extent_buffer *eb;
901 struct btrfs_root_item *root_item;
902 struct btrfs_key root_key;
903 int ret;
904
905 if (root->reloc_root) {
906 reloc_root = root->reloc_root;
907 reloc_root->last_trans = trans->transid;
908 return 0;
909 }
910
911 if (!root->fs_info->reloc_ctl ||
912 !root->fs_info->reloc_ctl->create_reloc_root ||
913 root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID)
914 return 0;
915
916 root_item = kmalloc(sizeof(*root_item), GFP_NOFS);
917 BUG_ON(!root_item);
918
919 root_key.objectid = BTRFS_TREE_RELOC_OBJECTID;
920 root_key.type = BTRFS_ROOT_ITEM_KEY;
921 root_key.offset = root->root_key.objectid;
922
923 ret = btrfs_copy_root(trans, root, root->commit_root, &eb,
924 BTRFS_TREE_RELOC_OBJECTID);
925 BUG_ON(ret);
926
927 btrfs_set_root_last_snapshot(&root->root_item, trans->transid - 1);
928 memcpy(root_item, &root->root_item, sizeof(*root_item));
929 btrfs_set_root_refs(root_item, 1);
930 btrfs_set_root_bytenr(root_item, eb->start);
931 btrfs_set_root_level(root_item, btrfs_header_level(eb));
932 btrfs_set_root_generation(root_item, trans->transid);
933 memset(&root_item->drop_progress, 0, sizeof(struct btrfs_disk_key));
934 root_item->drop_level = 0;
935
936 btrfs_tree_unlock(eb);
937 free_extent_buffer(eb);
938
939 ret = btrfs_insert_root(trans, root->fs_info->tree_root,
940 &root_key, root_item);
941 BUG_ON(ret);
942 kfree(root_item);
943
944 reloc_root = btrfs_read_fs_root_no_radix(root->fs_info->tree_root,
945 &root_key);
946 BUG_ON(IS_ERR(reloc_root));
947 reloc_root->last_trans = trans->transid;
948
949 __add_reloc_root(reloc_root);
950 root->reloc_root = reloc_root;
951 return 0;
952 }
953
954 /*
955 * update root item of reloc tree
956 */
957 int btrfs_update_reloc_root(struct btrfs_trans_handle *trans,
958 struct btrfs_root *root)
959 {
960 struct btrfs_root *reloc_root;
961 struct btrfs_root_item *root_item;
962 int del = 0;
963 int ret;
964
965 if (!root->reloc_root)
966 return 0;
967
968 reloc_root = root->reloc_root;
969 root_item = &reloc_root->root_item;
970
971 if (btrfs_root_refs(root_item) == 0) {
972 root->reloc_root = NULL;
973 del = 1;
974 }
975
976 __update_reloc_root(reloc_root, del);
977
978 if (reloc_root->commit_root != reloc_root->node) {
979 btrfs_set_root_node(root_item, reloc_root->node);
980 free_extent_buffer(reloc_root->commit_root);
981 reloc_root->commit_root = btrfs_root_node(reloc_root);
982 }
983
984 ret = btrfs_update_root(trans, root->fs_info->tree_root,
985 &reloc_root->root_key, root_item);
986 BUG_ON(ret);
987 return 0;
988 }
989
990 /*
991 * helper to find first cached inode with inode number >= objectid
992 * in a subvolume
993 */
994 static struct inode *find_next_inode(struct btrfs_root *root, u64 objectid)
995 {
996 struct rb_node *node;
997 struct rb_node *prev;
998 struct btrfs_inode *entry;
999 struct inode *inode;
1000
1001 spin_lock(&root->inode_lock);
1002 again:
1003 node = root->inode_tree.rb_node;
1004 prev = NULL;
1005 while (node) {
1006 prev = node;
1007 entry = rb_entry(node, struct btrfs_inode, rb_node);
1008
1009 if (objectid < entry->vfs_inode.i_ino)
1010 node = node->rb_left;
1011 else if (objectid > entry->vfs_inode.i_ino)
1012 node = node->rb_right;
1013 else
1014 break;
1015 }
1016 if (!node) {
1017 while (prev) {
1018 entry = rb_entry(prev, struct btrfs_inode, rb_node);
1019 if (objectid <= entry->vfs_inode.i_ino) {
1020 node = prev;
1021 break;
1022 }
1023 prev = rb_next(prev);
1024 }
1025 }
1026 while (node) {
1027 entry = rb_entry(node, struct btrfs_inode, rb_node);
1028 inode = igrab(&entry->vfs_inode);
1029 if (inode) {
1030 spin_unlock(&root->inode_lock);
1031 return inode;
1032 }
1033
1034 objectid = entry->vfs_inode.i_ino + 1;
1035 if (cond_resched_lock(&root->inode_lock))
1036 goto again;
1037
1038 node = rb_next(node);
1039 }
1040 spin_unlock(&root->inode_lock);
1041 return NULL;
1042 }
1043
1044 static int in_block_group(u64 bytenr,
1045 struct btrfs_block_group_cache *block_group)
1046 {
1047 if (bytenr >= block_group->key.objectid &&
1048 bytenr < block_group->key.objectid + block_group->key.offset)
1049 return 1;
1050 return 0;
1051 }
1052
1053 /*
1054 * get new location of data
1055 */
1056 static int get_new_location(struct inode *reloc_inode, u64 *new_bytenr,
1057 u64 bytenr, u64 num_bytes)
1058 {
1059 struct btrfs_root *root = BTRFS_I(reloc_inode)->root;
1060 struct btrfs_path *path;
1061 struct btrfs_file_extent_item *fi;
1062 struct extent_buffer *leaf;
1063 int ret;
1064
1065 path = btrfs_alloc_path();
1066 if (!path)
1067 return -ENOMEM;
1068
1069 bytenr -= BTRFS_I(reloc_inode)->index_cnt;
1070 ret = btrfs_lookup_file_extent(NULL, root, path, reloc_inode->i_ino,
1071 bytenr, 0);
1072 if (ret < 0)
1073 goto out;
1074 if (ret > 0) {
1075 ret = -ENOENT;
1076 goto out;
1077 }
1078
1079 leaf = path->nodes[0];
1080 fi = btrfs_item_ptr(leaf, path->slots[0],
1081 struct btrfs_file_extent_item);
1082
1083 BUG_ON(btrfs_file_extent_offset(leaf, fi) ||
1084 btrfs_file_extent_compression(leaf, fi) ||
1085 btrfs_file_extent_encryption(leaf, fi) ||
1086 btrfs_file_extent_other_encoding(leaf, fi));
1087
1088 if (num_bytes != btrfs_file_extent_disk_num_bytes(leaf, fi)) {
1089 ret = 1;
1090 goto out;
1091 }
1092
1093 if (new_bytenr)
1094 *new_bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
1095 ret = 0;
1096 out:
1097 btrfs_free_path(path);
1098 return ret;
1099 }
1100
1101 /*
1102 * update file extent items in the tree leaf to point to
1103 * the new locations.
1104 */
1105 static int replace_file_extents(struct btrfs_trans_handle *trans,
1106 struct reloc_control *rc,
1107 struct btrfs_root *root,
1108 struct extent_buffer *leaf,
1109 struct list_head *inode_list)
1110 {
1111 struct btrfs_key key;
1112 struct btrfs_file_extent_item *fi;
1113 struct inode *inode = NULL;
1114 struct inodevec *ivec = NULL;
1115 u64 parent;
1116 u64 bytenr;
1117 u64 new_bytenr;
1118 u64 num_bytes;
1119 u64 end;
1120 u32 nritems;
1121 u32 i;
1122 int ret;
1123 int first = 1;
1124 int dirty = 0;
1125
1126 if (rc->stage != UPDATE_DATA_PTRS)
1127 return 0;
1128
1129 /* reloc trees always use full backref */
1130 if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID)
1131 parent = leaf->start;
1132 else
1133 parent = 0;
1134
1135 nritems = btrfs_header_nritems(leaf);
1136 for (i = 0; i < nritems; i++) {
1137 cond_resched();
1138 btrfs_item_key_to_cpu(leaf, &key, i);
1139 if (key.type != BTRFS_EXTENT_DATA_KEY)
1140 continue;
1141 fi = btrfs_item_ptr(leaf, i, struct btrfs_file_extent_item);
1142 if (btrfs_file_extent_type(leaf, fi) ==
1143 BTRFS_FILE_EXTENT_INLINE)
1144 continue;
1145 bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
1146 num_bytes = btrfs_file_extent_disk_num_bytes(leaf, fi);
1147 if (bytenr == 0)
1148 continue;
1149 if (!in_block_group(bytenr, rc->block_group))
1150 continue;
1151
1152 /*
1153 * if we are modifying block in fs tree, wait for readpage
1154 * to complete and drop the extent cache
1155 */
1156 if (root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID) {
1157 if (!ivec || ivec->nr == INODEVEC_SIZE) {
1158 ivec = kmalloc(sizeof(*ivec), GFP_NOFS);
1159 BUG_ON(!ivec);
1160 ivec->nr = 0;
1161 list_add_tail(&ivec->list, inode_list);
1162 }
1163 if (first) {
1164 inode = find_next_inode(root, key.objectid);
1165 if (inode)
1166 ivec->inode[ivec->nr++] = inode;
1167 first = 0;
1168 } else if (inode && inode->i_ino < key.objectid) {
1169 inode = find_next_inode(root, key.objectid);
1170 if (inode)
1171 ivec->inode[ivec->nr++] = inode;
1172 }
1173 if (inode && inode->i_ino == key.objectid) {
1174 end = key.offset +
1175 btrfs_file_extent_num_bytes(leaf, fi);
1176 WARN_ON(!IS_ALIGNED(key.offset,
1177 root->sectorsize));
1178 WARN_ON(!IS_ALIGNED(end, root->sectorsize));
1179 end--;
1180 ret = try_lock_extent(&BTRFS_I(inode)->io_tree,
1181 key.offset, end,
1182 GFP_NOFS);
1183 if (!ret)
1184 continue;
1185
1186 btrfs_drop_extent_cache(inode, key.offset, end,
1187 1);
1188 unlock_extent(&BTRFS_I(inode)->io_tree,
1189 key.offset, end, GFP_NOFS);
1190 }
1191 }
1192
1193 ret = get_new_location(rc->data_inode, &new_bytenr,
1194 bytenr, num_bytes);
1195 if (ret > 0)
1196 continue;
1197 BUG_ON(ret < 0);
1198
1199 btrfs_set_file_extent_disk_bytenr(leaf, fi, new_bytenr);
1200 dirty = 1;
1201
1202 key.offset -= btrfs_file_extent_offset(leaf, fi);
1203 ret = btrfs_inc_extent_ref(trans, root, new_bytenr,
1204 num_bytes, parent,
1205 btrfs_header_owner(leaf),
1206 key.objectid, key.offset);
1207 BUG_ON(ret);
1208
1209 ret = btrfs_free_extent(trans, root, bytenr, num_bytes,
1210 parent, btrfs_header_owner(leaf),
1211 key.objectid, key.offset);
1212 BUG_ON(ret);
1213 }
1214 if (dirty)
1215 btrfs_mark_buffer_dirty(leaf);
1216 return 0;
1217 }
1218
1219 static noinline_for_stack
1220 int memcmp_node_keys(struct extent_buffer *eb, int slot,
1221 struct btrfs_path *path, int level)
1222 {
1223 struct btrfs_disk_key key1;
1224 struct btrfs_disk_key key2;
1225 btrfs_node_key(eb, &key1, slot);
1226 btrfs_node_key(path->nodes[level], &key2, path->slots[level]);
1227 return memcmp(&key1, &key2, sizeof(key1));
1228 }
1229
1230 /*
1231 * try to replace tree blocks in fs tree with the new blocks
1232 * in reloc tree. tree blocks haven't been modified since the
1233 * reloc tree was create can be replaced.
1234 *
1235 * if a block was replaced, level of the block + 1 is returned.
1236 * if no block got replaced, 0 is returned. if there are other
1237 * errors, a negative error number is returned.
1238 */
1239 static int replace_path(struct btrfs_trans_handle *trans,
1240 struct btrfs_root *dest, struct btrfs_root *src,
1241 struct btrfs_path *path, struct btrfs_key *next_key,
1242 struct extent_buffer **leaf,
1243 int lowest_level, int max_level)
1244 {
1245 struct extent_buffer *eb;
1246 struct extent_buffer *parent;
1247 struct btrfs_key key;
1248 u64 old_bytenr;
1249 u64 new_bytenr;
1250 u64 old_ptr_gen;
1251 u64 new_ptr_gen;
1252 u64 last_snapshot;
1253 u32 blocksize;
1254 int level;
1255 int ret;
1256 int slot;
1257
1258 BUG_ON(src->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID);
1259 BUG_ON(dest->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID);
1260 BUG_ON(lowest_level > 1 && leaf);
1261
1262 last_snapshot = btrfs_root_last_snapshot(&src->root_item);
1263
1264 slot = path->slots[lowest_level];
1265 btrfs_node_key_to_cpu(path->nodes[lowest_level], &key, slot);
1266
1267 eb = btrfs_lock_root_node(dest);
1268 btrfs_set_lock_blocking(eb);
1269 level = btrfs_header_level(eb);
1270
1271 if (level < lowest_level) {
1272 btrfs_tree_unlock(eb);
1273 free_extent_buffer(eb);
1274 return 0;
1275 }
1276
1277 ret = btrfs_cow_block(trans, dest, eb, NULL, 0, &eb);
1278 BUG_ON(ret);
1279 btrfs_set_lock_blocking(eb);
1280
1281 if (next_key) {
1282 next_key->objectid = (u64)-1;
1283 next_key->type = (u8)-1;
1284 next_key->offset = (u64)-1;
1285 }
1286
1287 parent = eb;
1288 while (1) {
1289 level = btrfs_header_level(parent);
1290 BUG_ON(level < lowest_level);
1291
1292 ret = btrfs_bin_search(parent, &key, level, &slot);
1293 if (ret && slot > 0)
1294 slot--;
1295
1296 if (next_key && slot + 1 < btrfs_header_nritems(parent))
1297 btrfs_node_key_to_cpu(parent, next_key, slot + 1);
1298
1299 old_bytenr = btrfs_node_blockptr(parent, slot);
1300 blocksize = btrfs_level_size(dest, level - 1);
1301 old_ptr_gen = btrfs_node_ptr_generation(parent, slot);
1302
1303 if (level <= max_level) {
1304 eb = path->nodes[level];
1305 new_bytenr = btrfs_node_blockptr(eb,
1306 path->slots[level]);
1307 new_ptr_gen = btrfs_node_ptr_generation(eb,
1308 path->slots[level]);
1309 } else {
1310 new_bytenr = 0;
1311 new_ptr_gen = 0;
1312 }
1313
1314 if (new_bytenr > 0 && new_bytenr == old_bytenr) {
1315 WARN_ON(1);
1316 ret = level;
1317 break;
1318 }
1319
1320 if (new_bytenr == 0 || old_ptr_gen > last_snapshot ||
1321 memcmp_node_keys(parent, slot, path, level)) {
1322 if (level <= lowest_level && !leaf) {
1323 ret = 0;
1324 break;
1325 }
1326
1327 eb = read_tree_block(dest, old_bytenr, blocksize,
1328 old_ptr_gen);
1329 btrfs_tree_lock(eb);
1330 ret = btrfs_cow_block(trans, dest, eb, parent,
1331 slot, &eb);
1332 BUG_ON(ret);
1333 btrfs_set_lock_blocking(eb);
1334
1335 if (level <= lowest_level) {
1336 *leaf = eb;
1337 ret = 0;
1338 break;
1339 }
1340
1341 btrfs_tree_unlock(parent);
1342 free_extent_buffer(parent);
1343
1344 parent = eb;
1345 continue;
1346 }
1347
1348 btrfs_node_key_to_cpu(path->nodes[level], &key,
1349 path->slots[level]);
1350 btrfs_release_path(src, path);
1351
1352 path->lowest_level = level;
1353 ret = btrfs_search_slot(trans, src, &key, path, 0, 1);
1354 path->lowest_level = 0;
1355 BUG_ON(ret);
1356
1357 /*
1358 * swap blocks in fs tree and reloc tree.
1359 */
1360 btrfs_set_node_blockptr(parent, slot, new_bytenr);
1361 btrfs_set_node_ptr_generation(parent, slot, new_ptr_gen);
1362 btrfs_mark_buffer_dirty(parent);
1363
1364 btrfs_set_node_blockptr(path->nodes[level],
1365 path->slots[level], old_bytenr);
1366 btrfs_set_node_ptr_generation(path->nodes[level],
1367 path->slots[level], old_ptr_gen);
1368 btrfs_mark_buffer_dirty(path->nodes[level]);
1369
1370 ret = btrfs_inc_extent_ref(trans, src, old_bytenr, blocksize,
1371 path->nodes[level]->start,
1372 src->root_key.objectid, level - 1, 0);
1373 BUG_ON(ret);
1374 ret = btrfs_inc_extent_ref(trans, dest, new_bytenr, blocksize,
1375 0, dest->root_key.objectid, level - 1,
1376 0);
1377 BUG_ON(ret);
1378
1379 ret = btrfs_free_extent(trans, src, new_bytenr, blocksize,
1380 path->nodes[level]->start,
1381 src->root_key.objectid, level - 1, 0);
1382 BUG_ON(ret);
1383
1384 ret = btrfs_free_extent(trans, dest, old_bytenr, blocksize,
1385 0, dest->root_key.objectid, level - 1,
1386 0);
1387 BUG_ON(ret);
1388
1389 btrfs_unlock_up_safe(path, 0);
1390
1391 ret = level;
1392 break;
1393 }
1394 btrfs_tree_unlock(parent);
1395 free_extent_buffer(parent);
1396 return ret;
1397 }
1398
1399 /*
1400 * helper to find next relocated block in reloc tree
1401 */
1402 static noinline_for_stack
1403 int walk_up_reloc_tree(struct btrfs_root *root, struct btrfs_path *path,
1404 int *level)
1405 {
1406 struct extent_buffer *eb;
1407 int i;
1408 u64 last_snapshot;
1409 u32 nritems;
1410
1411 last_snapshot = btrfs_root_last_snapshot(&root->root_item);
1412
1413 for (i = 0; i < *level; i++) {
1414 free_extent_buffer(path->nodes[i]);
1415 path->nodes[i] = NULL;
1416 }
1417
1418 for (i = *level; i < BTRFS_MAX_LEVEL && path->nodes[i]; i++) {
1419 eb = path->nodes[i];
1420 nritems = btrfs_header_nritems(eb);
1421 while (path->slots[i] + 1 < nritems) {
1422 path->slots[i]++;
1423 if (btrfs_node_ptr_generation(eb, path->slots[i]) <=
1424 last_snapshot)
1425 continue;
1426
1427 *level = i;
1428 return 0;
1429 }
1430 free_extent_buffer(path->nodes[i]);
1431 path->nodes[i] = NULL;
1432 }
1433 return 1;
1434 }
1435
1436 /*
1437 * walk down reloc tree to find relocated block of lowest level
1438 */
1439 static noinline_for_stack
1440 int walk_down_reloc_tree(struct btrfs_root *root, struct btrfs_path *path,
1441 int *level)
1442 {
1443 struct extent_buffer *eb = NULL;
1444 int i;
1445 u64 bytenr;
1446 u64 ptr_gen = 0;
1447 u64 last_snapshot;
1448 u32 blocksize;
1449 u32 nritems;
1450
1451 last_snapshot = btrfs_root_last_snapshot(&root->root_item);
1452
1453 for (i = *level; i > 0; i--) {
1454 eb = path->nodes[i];
1455 nritems = btrfs_header_nritems(eb);
1456 while (path->slots[i] < nritems) {
1457 ptr_gen = btrfs_node_ptr_generation(eb, path->slots[i]);
1458 if (ptr_gen > last_snapshot)
1459 break;
1460 path->slots[i]++;
1461 }
1462 if (path->slots[i] >= nritems) {
1463 if (i == *level)
1464 break;
1465 *level = i + 1;
1466 return 0;
1467 }
1468 if (i == 1) {
1469 *level = i;
1470 return 0;
1471 }
1472
1473 bytenr = btrfs_node_blockptr(eb, path->slots[i]);
1474 blocksize = btrfs_level_size(root, i - 1);
1475 eb = read_tree_block(root, bytenr, blocksize, ptr_gen);
1476 BUG_ON(btrfs_header_level(eb) != i - 1);
1477 path->nodes[i - 1] = eb;
1478 path->slots[i - 1] = 0;
1479 }
1480 return 1;
1481 }
1482
1483 /*
1484 * invalidate extent cache for file extents whose key in range of
1485 * [min_key, max_key)
1486 */
1487 static int invalidate_extent_cache(struct btrfs_root *root,
1488 struct btrfs_key *min_key,
1489 struct btrfs_key *max_key)
1490 {
1491 struct inode *inode = NULL;
1492 u64 objectid;
1493 u64 start, end;
1494
1495 objectid = min_key->objectid;
1496 while (1) {
1497 cond_resched();
1498 iput(inode);
1499
1500 if (objectid > max_key->objectid)
1501 break;
1502
1503 inode = find_next_inode(root, objectid);
1504 if (!inode)
1505 break;
1506
1507 if (inode->i_ino > max_key->objectid) {
1508 iput(inode);
1509 break;
1510 }
1511
1512 objectid = inode->i_ino + 1;
1513 if (!S_ISREG(inode->i_mode))
1514 continue;
1515
1516 if (unlikely(min_key->objectid == inode->i_ino)) {
1517 if (min_key->type > BTRFS_EXTENT_DATA_KEY)
1518 continue;
1519 if (min_key->type < BTRFS_EXTENT_DATA_KEY)
1520 start = 0;
1521 else {
1522 start = min_key->offset;
1523 WARN_ON(!IS_ALIGNED(start, root->sectorsize));
1524 }
1525 } else {
1526 start = 0;
1527 }
1528
1529 if (unlikely(max_key->objectid == inode->i_ino)) {
1530 if (max_key->type < BTRFS_EXTENT_DATA_KEY)
1531 continue;
1532 if (max_key->type > BTRFS_EXTENT_DATA_KEY) {
1533 end = (u64)-1;
1534 } else {
1535 if (max_key->offset == 0)
1536 continue;
1537 end = max_key->offset;
1538 WARN_ON(!IS_ALIGNED(end, root->sectorsize));
1539 end--;
1540 }
1541 } else {
1542 end = (u64)-1;
1543 }
1544
1545 /* the lock_extent waits for readpage to complete */
1546 lock_extent(&BTRFS_I(inode)->io_tree, start, end, GFP_NOFS);
1547 btrfs_drop_extent_cache(inode, start, end, 1);
1548 unlock_extent(&BTRFS_I(inode)->io_tree, start, end, GFP_NOFS);
1549 }
1550 return 0;
1551 }
1552
1553 static int find_next_key(struct btrfs_path *path, int level,
1554 struct btrfs_key *key)
1555
1556 {
1557 while (level < BTRFS_MAX_LEVEL) {
1558 if (!path->nodes[level])
1559 break;
1560 if (path->slots[level] + 1 <
1561 btrfs_header_nritems(path->nodes[level])) {
1562 btrfs_node_key_to_cpu(path->nodes[level], key,
1563 path->slots[level] + 1);
1564 return 0;
1565 }
1566 level++;
1567 }
1568 return 1;
1569 }
1570
1571 /*
1572 * merge the relocated tree blocks in reloc tree with corresponding
1573 * fs tree.
1574 */
1575 static noinline_for_stack int merge_reloc_root(struct reloc_control *rc,
1576 struct btrfs_root *root)
1577 {
1578 LIST_HEAD(inode_list);
1579 struct btrfs_key key;
1580 struct btrfs_key next_key;
1581 struct btrfs_trans_handle *trans;
1582 struct btrfs_root *reloc_root;
1583 struct btrfs_root_item *root_item;
1584 struct btrfs_path *path;
1585 struct extent_buffer *leaf = NULL;
1586 unsigned long nr;
1587 int level;
1588 int max_level;
1589 int replaced = 0;
1590 int ret;
1591 int err = 0;
1592
1593 path = btrfs_alloc_path();
1594 if (!path)
1595 return -ENOMEM;
1596
1597 reloc_root = root->reloc_root;
1598 root_item = &reloc_root->root_item;
1599
1600 if (btrfs_disk_key_objectid(&root_item->drop_progress) == 0) {
1601 level = btrfs_root_level(root_item);
1602 extent_buffer_get(reloc_root->node);
1603 path->nodes[level] = reloc_root->node;
1604 path->slots[level] = 0;
1605 } else {
1606 btrfs_disk_key_to_cpu(&key, &root_item->drop_progress);
1607
1608 level = root_item->drop_level;
1609 BUG_ON(level == 0);
1610 path->lowest_level = level;
1611 ret = btrfs_search_slot(NULL, reloc_root, &key, path, 0, 0);
1612 if (ret < 0) {
1613 btrfs_free_path(path);
1614 return ret;
1615 }
1616
1617 btrfs_node_key_to_cpu(path->nodes[level], &next_key,
1618 path->slots[level]);
1619 WARN_ON(memcmp(&key, &next_key, sizeof(key)));
1620
1621 btrfs_unlock_up_safe(path, 0);
1622 }
1623
1624 if (level == 0 && rc->stage == UPDATE_DATA_PTRS) {
1625 trans = btrfs_start_transaction(root, 1);
1626
1627 leaf = path->nodes[0];
1628 btrfs_item_key_to_cpu(leaf, &key, 0);
1629 btrfs_release_path(reloc_root, path);
1630
1631 ret = btrfs_search_slot(trans, root, &key, path, 0, 1);
1632 if (ret < 0) {
1633 err = ret;
1634 goto out;
1635 }
1636
1637 leaf = path->nodes[0];
1638 btrfs_unlock_up_safe(path, 1);
1639 ret = replace_file_extents(trans, rc, root, leaf,
1640 &inode_list);
1641 if (ret < 0)
1642 err = ret;
1643 goto out;
1644 }
1645
1646 memset(&next_key, 0, sizeof(next_key));
1647
1648 while (1) {
1649 leaf = NULL;
1650 replaced = 0;
1651 trans = btrfs_start_transaction(root, 1);
1652 max_level = level;
1653
1654 ret = walk_down_reloc_tree(reloc_root, path, &level);
1655 if (ret < 0) {
1656 err = ret;
1657 goto out;
1658 }
1659 if (ret > 0)
1660 break;
1661
1662 if (!find_next_key(path, level, &key) &&
1663 btrfs_comp_cpu_keys(&next_key, &key) >= 0) {
1664 ret = 0;
1665 } else if (level == 1 && rc->stage == UPDATE_DATA_PTRS) {
1666 ret = replace_path(trans, root, reloc_root,
1667 path, &next_key, &leaf,
1668 level, max_level);
1669 } else {
1670 ret = replace_path(trans, root, reloc_root,
1671 path, &next_key, NULL,
1672 level, max_level);
1673 }
1674 if (ret < 0) {
1675 err = ret;
1676 goto out;
1677 }
1678
1679 if (ret > 0) {
1680 level = ret;
1681 btrfs_node_key_to_cpu(path->nodes[level], &key,
1682 path->slots[level]);
1683 replaced = 1;
1684 } else if (leaf) {
1685 /*
1686 * no block got replaced, try replacing file extents
1687 */
1688 btrfs_item_key_to_cpu(leaf, &key, 0);
1689 ret = replace_file_extents(trans, rc, root, leaf,
1690 &inode_list);
1691 btrfs_tree_unlock(leaf);
1692 free_extent_buffer(leaf);
1693 BUG_ON(ret < 0);
1694 }
1695
1696 ret = walk_up_reloc_tree(reloc_root, path, &level);
1697 if (ret > 0)
1698 break;
1699
1700 BUG_ON(level == 0);
1701 /*
1702 * save the merging progress in the drop_progress.
1703 * this is OK since root refs == 1 in this case.
1704 */
1705 btrfs_node_key(path->nodes[level], &root_item->drop_progress,
1706 path->slots[level]);
1707 root_item->drop_level = level;
1708
1709 nr = trans->blocks_used;
1710 btrfs_end_transaction(trans, root);
1711
1712 btrfs_btree_balance_dirty(root, nr);
1713
1714 if (replaced && rc->stage == UPDATE_DATA_PTRS)
1715 invalidate_extent_cache(root, &key, &next_key);
1716 }
1717
1718 /*
1719 * handle the case only one block in the fs tree need to be
1720 * relocated and the block is tree root.
1721 */
1722 leaf = btrfs_lock_root_node(root);
1723 ret = btrfs_cow_block(trans, root, leaf, NULL, 0, &leaf);
1724 btrfs_tree_unlock(leaf);
1725 free_extent_buffer(leaf);
1726 if (ret < 0)
1727 err = ret;
1728 out:
1729 btrfs_free_path(path);
1730
1731 if (err == 0) {
1732 memset(&root_item->drop_progress, 0,
1733 sizeof(root_item->drop_progress));
1734 root_item->drop_level = 0;
1735 btrfs_set_root_refs(root_item, 0);
1736 }
1737
1738 nr = trans->blocks_used;
1739 btrfs_end_transaction(trans, root);
1740
1741 btrfs_btree_balance_dirty(root, nr);
1742
1743 /*
1744 * put inodes while we aren't holding the tree locks
1745 */
1746 while (!list_empty(&inode_list)) {
1747 struct inodevec *ivec;
1748 ivec = list_entry(inode_list.next, struct inodevec, list);
1749 list_del(&ivec->list);
1750 while (ivec->nr > 0) {
1751 ivec->nr--;
1752 iput(ivec->inode[ivec->nr]);
1753 }
1754 kfree(ivec);
1755 }
1756
1757 if (replaced && rc->stage == UPDATE_DATA_PTRS)
1758 invalidate_extent_cache(root, &key, &next_key);
1759
1760 return err;
1761 }
1762
1763 /*
1764 * callback for the work threads.
1765 * this function merges reloc tree with corresponding fs tree,
1766 * and then drops the reloc tree.
1767 */
1768 static void merge_func(struct btrfs_work *work)
1769 {
1770 struct btrfs_trans_handle *trans;
1771 struct btrfs_root *root;
1772 struct btrfs_root *reloc_root;
1773 struct async_merge *async;
1774
1775 async = container_of(work, struct async_merge, work);
1776 reloc_root = async->root;
1777
1778 if (btrfs_root_refs(&reloc_root->root_item) > 0) {
1779 root = read_fs_root(reloc_root->fs_info,
1780 reloc_root->root_key.offset);
1781 BUG_ON(IS_ERR(root));
1782 BUG_ON(root->reloc_root != reloc_root);
1783
1784 merge_reloc_root(async->rc, root);
1785
1786 trans = btrfs_start_transaction(root, 1);
1787 btrfs_update_reloc_root(trans, root);
1788 btrfs_end_transaction(trans, root);
1789 }
1790
1791 btrfs_drop_dead_root(reloc_root);
1792
1793 if (atomic_dec_and_test(async->num_pending))
1794 complete(async->done);
1795
1796 kfree(async);
1797 }
1798
1799 static int merge_reloc_roots(struct reloc_control *rc)
1800 {
1801 struct async_merge *async;
1802 struct btrfs_root *root;
1803 struct completion done;
1804 atomic_t num_pending;
1805
1806 init_completion(&done);
1807 atomic_set(&num_pending, 1);
1808
1809 while (!list_empty(&rc->reloc_roots)) {
1810 root = list_entry(rc->reloc_roots.next,
1811 struct btrfs_root, root_list);
1812 list_del_init(&root->root_list);
1813
1814 async = kmalloc(sizeof(*async), GFP_NOFS);
1815 BUG_ON(!async);
1816 async->work.func = merge_func;
1817 async->work.flags = 0;
1818 async->rc = rc;
1819 async->root = root;
1820 async->done = &done;
1821 async->num_pending = &num_pending;
1822 atomic_inc(&num_pending);
1823 btrfs_queue_worker(&rc->workers, &async->work);
1824 }
1825
1826 if (!atomic_dec_and_test(&num_pending))
1827 wait_for_completion(&done);
1828
1829 BUG_ON(!RB_EMPTY_ROOT(&rc->reloc_root_tree.rb_root));
1830 return 0;
1831 }
1832
1833 static void free_block_list(struct rb_root *blocks)
1834 {
1835 struct tree_block *block;
1836 struct rb_node *rb_node;
1837 while ((rb_node = rb_first(blocks))) {
1838 block = rb_entry(rb_node, struct tree_block, rb_node);
1839 rb_erase(rb_node, blocks);
1840 kfree(block);
1841 }
1842 }
1843
1844 static int record_reloc_root_in_trans(struct btrfs_trans_handle *trans,
1845 struct btrfs_root *reloc_root)
1846 {
1847 struct btrfs_root *root;
1848
1849 if (reloc_root->last_trans == trans->transid)
1850 return 0;
1851
1852 root = read_fs_root(reloc_root->fs_info, reloc_root->root_key.offset);
1853 BUG_ON(IS_ERR(root));
1854 BUG_ON(root->reloc_root != reloc_root);
1855
1856 return btrfs_record_root_in_trans(trans, root);
1857 }
1858
1859 /*
1860 * select one tree from trees that references the block.
1861 * for blocks in refernce counted trees, we preper reloc tree.
1862 * if no reloc tree found and reloc_only is true, NULL is returned.
1863 */
1864 static struct btrfs_root *__select_one_root(struct btrfs_trans_handle *trans,
1865 struct backref_node *node,
1866 struct backref_edge *edges[],
1867 int *nr, int reloc_only)
1868 {
1869 struct backref_node *next;
1870 struct btrfs_root *root;
1871 int index;
1872 int loop = 0;
1873 again:
1874 index = 0;
1875 next = node;
1876 while (1) {
1877 cond_resched();
1878 next = walk_up_backref(next, edges, &index);
1879 root = next->root;
1880 if (!root) {
1881 BUG_ON(!node->old_root);
1882 goto skip;
1883 }
1884
1885 /* no other choice for non-refernce counted tree */
1886 if (!root->ref_cows) {
1887 BUG_ON(reloc_only);
1888 break;
1889 }
1890
1891 if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID) {
1892 record_reloc_root_in_trans(trans, root);
1893 break;
1894 }
1895
1896 if (loop) {
1897 btrfs_record_root_in_trans(trans, root);
1898 break;
1899 }
1900
1901 if (reloc_only || next != node) {
1902 if (!root->reloc_root)
1903 btrfs_record_root_in_trans(trans, root);
1904 root = root->reloc_root;
1905 /*
1906 * if the reloc tree was created in current
1907 * transation, there is no node in backref tree
1908 * corresponds to the root of the reloc tree.
1909 */
1910 if (btrfs_root_last_snapshot(&root->root_item) ==
1911 trans->transid - 1)
1912 break;
1913 }
1914 skip:
1915 root = NULL;
1916 next = walk_down_backref(edges, &index);
1917 if (!next || next->level <= node->level)
1918 break;
1919 }
1920
1921 if (!root && !loop && !reloc_only) {
1922 loop = 1;
1923 goto again;
1924 }
1925
1926 if (root)
1927 *nr = index;
1928 else
1929 *nr = 0;
1930
1931 return root;
1932 }
1933
1934 static noinline_for_stack
1935 struct btrfs_root *select_one_root(struct btrfs_trans_handle *trans,
1936 struct backref_node *node)
1937 {
1938 struct backref_edge *edges[BTRFS_MAX_LEVEL - 1];
1939 int nr;
1940 return __select_one_root(trans, node, edges, &nr, 0);
1941 }
1942
1943 static noinline_for_stack
1944 struct btrfs_root *select_reloc_root(struct btrfs_trans_handle *trans,
1945 struct backref_node *node,
1946 struct backref_edge *edges[], int *nr)
1947 {
1948 return __select_one_root(trans, node, edges, nr, 1);
1949 }
1950
1951 static void grab_path_buffers(struct btrfs_path *path,
1952 struct backref_node *node,
1953 struct backref_edge *edges[], int nr)
1954 {
1955 int i = 0;
1956 while (1) {
1957 drop_node_buffer(node);
1958 node->eb = path->nodes[node->level];
1959 BUG_ON(!node->eb);
1960 if (path->locks[node->level])
1961 node->locked = 1;
1962 path->nodes[node->level] = NULL;
1963 path->locks[node->level] = 0;
1964
1965 if (i >= nr)
1966 break;
1967
1968 edges[i]->blockptr = node->eb->start;
1969 node = edges[i]->node[UPPER];
1970 i++;
1971 }
1972 }
1973
1974 /*
1975 * relocate a block tree, and then update pointers in upper level
1976 * blocks that reference the block to point to the new location.
1977 *
1978 * if called by link_to_upper, the block has already been relocated.
1979 * in that case this function just updates pointers.
1980 */
1981 static int do_relocation(struct btrfs_trans_handle *trans,
1982 struct backref_node *node,
1983 struct btrfs_key *key,
1984 struct btrfs_path *path, int lowest)
1985 {
1986 struct backref_node *upper;
1987 struct backref_edge *edge;
1988 struct backref_edge *edges[BTRFS_MAX_LEVEL - 1];
1989 struct btrfs_root *root;
1990 struct extent_buffer *eb;
1991 u32 blocksize;
1992 u64 bytenr;
1993 u64 generation;
1994 int nr;
1995 int slot;
1996 int ret;
1997 int err = 0;
1998
1999 BUG_ON(lowest && node->eb);
2000
2001 path->lowest_level = node->level + 1;
2002 list_for_each_entry(edge, &node->upper, list[LOWER]) {
2003 cond_resched();
2004 if (node->eb && node->eb->start == edge->blockptr)
2005 continue;
2006
2007 upper = edge->node[UPPER];
2008 root = select_reloc_root(trans, upper, edges, &nr);
2009 if (!root)
2010 continue;
2011
2012 if (upper->eb && !upper->locked)
2013 drop_node_buffer(upper);
2014
2015 if (!upper->eb) {
2016 ret = btrfs_search_slot(trans, root, key, path, 0, 1);
2017 if (ret < 0) {
2018 err = ret;
2019 break;
2020 }
2021 BUG_ON(ret > 0);
2022
2023 slot = path->slots[upper->level];
2024
2025 btrfs_unlock_up_safe(path, upper->level + 1);
2026 grab_path_buffers(path, upper, edges, nr);
2027
2028 btrfs_release_path(NULL, path);
2029 } else {
2030 ret = btrfs_bin_search(upper->eb, key, upper->level,
2031 &slot);
2032 BUG_ON(ret);
2033 }
2034
2035 bytenr = btrfs_node_blockptr(upper->eb, slot);
2036 if (!lowest) {
2037 if (node->eb->start == bytenr) {
2038 btrfs_tree_unlock(upper->eb);
2039 upper->locked = 0;
2040 continue;
2041 }
2042 } else {
2043 BUG_ON(node->bytenr != bytenr);
2044 }
2045
2046 blocksize = btrfs_level_size(root, node->level);
2047 generation = btrfs_node_ptr_generation(upper->eb, slot);
2048 eb = read_tree_block(root, bytenr, blocksize, generation);
2049 btrfs_tree_lock(eb);
2050 btrfs_set_lock_blocking(eb);
2051
2052 if (!node->eb) {
2053 ret = btrfs_cow_block(trans, root, eb, upper->eb,
2054 slot, &eb);
2055 if (ret < 0) {
2056 err = ret;
2057 break;
2058 }
2059 btrfs_set_lock_blocking(eb);
2060 node->eb = eb;
2061 node->locked = 1;
2062 } else {
2063 btrfs_set_node_blockptr(upper->eb, slot,
2064 node->eb->start);
2065 btrfs_set_node_ptr_generation(upper->eb, slot,
2066 trans->transid);
2067 btrfs_mark_buffer_dirty(upper->eb);
2068
2069 ret = btrfs_inc_extent_ref(trans, root,
2070 node->eb->start, blocksize,
2071 upper->eb->start,
2072 btrfs_header_owner(upper->eb),
2073 node->level, 0);
2074 BUG_ON(ret);
2075
2076 ret = btrfs_drop_subtree(trans, root, eb, upper->eb);
2077 BUG_ON(ret);
2078
2079 btrfs_tree_unlock(eb);
2080 free_extent_buffer(eb);
2081 }
2082 if (!lowest) {
2083 btrfs_tree_unlock(upper->eb);
2084 upper->locked = 0;
2085 }
2086 }
2087 path->lowest_level = 0;
2088 return err;
2089 }
2090
2091 static int link_to_upper(struct btrfs_trans_handle *trans,
2092 struct backref_node *node,
2093 struct btrfs_path *path)
2094 {
2095 struct btrfs_key key;
2096 if (!node->eb || list_empty(&node->upper))
2097 return 0;
2098
2099 btrfs_node_key_to_cpu(node->eb, &key, 0);
2100 return do_relocation(trans, node, &key, path, 0);
2101 }
2102
2103 static int finish_pending_nodes(struct btrfs_trans_handle *trans,
2104 struct backref_cache *cache,
2105 struct btrfs_path *path)
2106 {
2107 struct backref_node *node;
2108 int level;
2109 int ret;
2110 int err = 0;
2111
2112 for (level = 0; level < BTRFS_MAX_LEVEL; level++) {
2113 while (!list_empty(&cache->pending[level])) {
2114 node = list_entry(cache->pending[level].next,
2115 struct backref_node, lower);
2116 BUG_ON(node->level != level);
2117
2118 ret = link_to_upper(trans, node, path);
2119 if (ret < 0)
2120 err = ret;
2121 /*
2122 * this remove the node from the pending list and
2123 * may add some other nodes to the level + 1
2124 * pending list
2125 */
2126 remove_backref_node(cache, node);
2127 }
2128 }
2129 BUG_ON(!RB_EMPTY_ROOT(&cache->rb_root));
2130 return err;
2131 }
2132
2133 static void mark_block_processed(struct reloc_control *rc,
2134 struct backref_node *node)
2135 {
2136 u32 blocksize;
2137 if (node->level == 0 ||
2138 in_block_group(node->bytenr, rc->block_group)) {
2139 blocksize = btrfs_level_size(rc->extent_root, node->level);
2140 set_extent_bits(&rc->processed_blocks, node->bytenr,
2141 node->bytenr + blocksize - 1, EXTENT_DIRTY,
2142 GFP_NOFS);
2143 }
2144 node->processed = 1;
2145 }
2146
2147 /*
2148 * mark a block and all blocks directly/indirectly reference the block
2149 * as processed.
2150 */
2151 static void update_processed_blocks(struct reloc_control *rc,
2152 struct backref_node *node)
2153 {
2154 struct backref_node *next = node;
2155 struct backref_edge *edge;
2156 struct backref_edge *edges[BTRFS_MAX_LEVEL - 1];
2157 int index = 0;
2158
2159 while (next) {
2160 cond_resched();
2161 while (1) {
2162 if (next->processed)
2163 break;
2164
2165 mark_block_processed(rc, next);
2166
2167 if (list_empty(&next->upper))
2168 break;
2169
2170 edge = list_entry(next->upper.next,
2171 struct backref_edge, list[LOWER]);
2172 edges[index++] = edge;
2173 next = edge->node[UPPER];
2174 }
2175 next = walk_down_backref(edges, &index);
2176 }
2177 }
2178
2179 static int tree_block_processed(u64 bytenr, u32 blocksize,
2180 struct reloc_control *rc)
2181 {
2182 if (test_range_bit(&rc->processed_blocks, bytenr,
2183 bytenr + blocksize - 1, EXTENT_DIRTY, 1))
2184 return 1;
2185 return 0;
2186 }
2187
2188 /*
2189 * check if there are any file extent pointers in the leaf point to
2190 * data require processing
2191 */
2192 static int check_file_extents(struct reloc_control *rc,
2193 u64 bytenr, u32 blocksize, u64 ptr_gen)
2194 {
2195 struct btrfs_key found_key;
2196 struct btrfs_file_extent_item *fi;
2197 struct extent_buffer *leaf;
2198 u32 nritems;
2199 int i;
2200 int ret = 0;
2201
2202 leaf = read_tree_block(rc->extent_root, bytenr, blocksize, ptr_gen);
2203
2204 nritems = btrfs_header_nritems(leaf);
2205 for (i = 0; i < nritems; i++) {
2206 cond_resched();
2207 btrfs_item_key_to_cpu(leaf, &found_key, i);
2208 if (found_key.type != BTRFS_EXTENT_DATA_KEY)
2209 continue;
2210 fi = btrfs_item_ptr(leaf, i, struct btrfs_file_extent_item);
2211 if (btrfs_file_extent_type(leaf, fi) ==
2212 BTRFS_FILE_EXTENT_INLINE)
2213 continue;
2214 bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
2215 if (bytenr == 0)
2216 continue;
2217 if (in_block_group(bytenr, rc->block_group)) {
2218 ret = 1;
2219 break;
2220 }
2221 }
2222 free_extent_buffer(leaf);
2223 return ret;
2224 }
2225
2226 /*
2227 * scan child blocks of a given block to find blocks require processing
2228 */
2229 static int add_child_blocks(struct btrfs_trans_handle *trans,
2230 struct reloc_control *rc,
2231 struct backref_node *node,
2232 struct rb_root *blocks)
2233 {
2234 struct tree_block *block;
2235 struct rb_node *rb_node;
2236 u64 bytenr;
2237 u64 ptr_gen;
2238 u32 blocksize;
2239 u32 nritems;
2240 int i;
2241 int err = 0;
2242
2243 nritems = btrfs_header_nritems(node->eb);
2244 blocksize = btrfs_level_size(rc->extent_root, node->level - 1);
2245 for (i = 0; i < nritems; i++) {
2246 cond_resched();
2247 bytenr = btrfs_node_blockptr(node->eb, i);
2248 ptr_gen = btrfs_node_ptr_generation(node->eb, i);
2249 if (ptr_gen == trans->transid)
2250 continue;
2251 if (!in_block_group(bytenr, rc->block_group) &&
2252 (node->level > 1 || rc->stage == MOVE_DATA_EXTENTS))
2253 continue;
2254 if (tree_block_processed(bytenr, blocksize, rc))
2255 continue;
2256
2257 readahead_tree_block(rc->extent_root,
2258 bytenr, blocksize, ptr_gen);
2259 }
2260
2261 for (i = 0; i < nritems; i++) {
2262 cond_resched();
2263 bytenr = btrfs_node_blockptr(node->eb, i);
2264 ptr_gen = btrfs_node_ptr_generation(node->eb, i);
2265 if (ptr_gen == trans->transid)
2266 continue;
2267 if (!in_block_group(bytenr, rc->block_group) &&
2268 (node->level > 1 || rc->stage == MOVE_DATA_EXTENTS))
2269 continue;
2270 if (tree_block_processed(bytenr, blocksize, rc))
2271 continue;
2272 if (!in_block_group(bytenr, rc->block_group) &&
2273 !check_file_extents(rc, bytenr, blocksize, ptr_gen))
2274 continue;
2275
2276 block = kmalloc(sizeof(*block), GFP_NOFS);
2277 if (!block) {
2278 err = -ENOMEM;
2279 break;
2280 }
2281 block->bytenr = bytenr;
2282 btrfs_node_key_to_cpu(node->eb, &block->key, i);
2283 block->level = node->level - 1;
2284 block->key_ready = 1;
2285 rb_node = tree_insert(blocks, block->bytenr, &block->rb_node);
2286 BUG_ON(rb_node);
2287 }
2288 if (err)
2289 free_block_list(blocks);
2290 return err;
2291 }
2292
2293 /*
2294 * find adjacent blocks require processing
2295 */
2296 static noinline_for_stack
2297 int add_adjacent_blocks(struct btrfs_trans_handle *trans,
2298 struct reloc_control *rc,
2299 struct backref_cache *cache,
2300 struct rb_root *blocks, int level,
2301 struct backref_node **upper)
2302 {
2303 struct backref_node *node;
2304 int ret = 0;
2305
2306 WARN_ON(!list_empty(&cache->pending[level]));
2307
2308 if (list_empty(&cache->pending[level + 1]))
2309 return 1;
2310
2311 node = list_entry(cache->pending[level + 1].next,
2312 struct backref_node, lower);
2313 if (node->eb)
2314 ret = add_child_blocks(trans, rc, node, blocks);
2315
2316 *upper = node;
2317 return ret;
2318 }
2319
2320 static int get_tree_block_key(struct reloc_control *rc,
2321 struct tree_block *block)
2322 {
2323 struct extent_buffer *eb;
2324
2325 BUG_ON(block->key_ready);
2326 eb = read_tree_block(rc->extent_root, block->bytenr,
2327 block->key.objectid, block->key.offset);
2328 WARN_ON(btrfs_header_level(eb) != block->level);
2329 if (block->level == 0)
2330 btrfs_item_key_to_cpu(eb, &block->key, 0);
2331 else
2332 btrfs_node_key_to_cpu(eb, &block->key, 0);
2333 free_extent_buffer(eb);
2334 block->key_ready = 1;
2335 return 0;
2336 }
2337
2338 static int reada_tree_block(struct reloc_control *rc,
2339 struct tree_block *block)
2340 {
2341 BUG_ON(block->key_ready);
2342 readahead_tree_block(rc->extent_root, block->bytenr,
2343 block->key.objectid, block->key.offset);
2344 return 0;
2345 }
2346
2347 /*
2348 * helper function to relocate a tree block
2349 */
2350 static int relocate_tree_block(struct btrfs_trans_handle *trans,
2351 struct reloc_control *rc,
2352 struct backref_node *node,
2353 struct btrfs_key *key,
2354 struct btrfs_path *path)
2355 {
2356 struct btrfs_root *root;
2357 int ret;
2358
2359 root = select_one_root(trans, node);
2360 if (unlikely(!root)) {
2361 rc->found_old_snapshot = 1;
2362 update_processed_blocks(rc, node);
2363 return 0;
2364 }
2365
2366 if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID) {
2367 ret = do_relocation(trans, node, key, path, 1);
2368 if (ret < 0)
2369 goto out;
2370 if (node->level == 0 && rc->stage == UPDATE_DATA_PTRS) {
2371 ret = replace_file_extents(trans, rc, root,
2372 node->eb, NULL);
2373 if (ret < 0)
2374 goto out;
2375 }
2376 drop_node_buffer(node);
2377 } else if (!root->ref_cows) {
2378 path->lowest_level = node->level;
2379 ret = btrfs_search_slot(trans, root, key, path, 0, 1);
2380 btrfs_release_path(root, path);
2381 if (ret < 0)
2382 goto out;
2383 } else if (root != node->root) {
2384 WARN_ON(node->level > 0 || rc->stage != UPDATE_DATA_PTRS);
2385 }
2386
2387 update_processed_blocks(rc, node);
2388 ret = 0;
2389 out:
2390 drop_node_buffer(node);
2391 return ret;
2392 }
2393
2394 /*
2395 * relocate a list of blocks
2396 */
2397 static noinline_for_stack
2398 int relocate_tree_blocks(struct btrfs_trans_handle *trans,
2399 struct reloc_control *rc, struct rb_root *blocks)
2400 {
2401 struct backref_cache *cache;
2402 struct backref_node *node;
2403 struct btrfs_path *path;
2404 struct tree_block *block;
2405 struct rb_node *rb_node;
2406 int level = -1;
2407 int ret;
2408 int err = 0;
2409
2410 path = btrfs_alloc_path();
2411 if (!path)
2412 return -ENOMEM;
2413
2414 cache = kmalloc(sizeof(*cache), GFP_NOFS);
2415 if (!cache) {
2416 btrfs_free_path(path);
2417 return -ENOMEM;
2418 }
2419
2420 backref_cache_init(cache);
2421
2422 rb_node = rb_first(blocks);
2423 while (rb_node) {
2424 block = rb_entry(rb_node, struct tree_block, rb_node);
2425 if (level == -1)
2426 level = block->level;
2427 else
2428 BUG_ON(level != block->level);
2429 if (!block->key_ready)
2430 reada_tree_block(rc, block);
2431 rb_node = rb_next(rb_node);
2432 }
2433
2434 rb_node = rb_first(blocks);
2435 while (rb_node) {
2436 block = rb_entry(rb_node, struct tree_block, rb_node);
2437 if (!block->key_ready)
2438 get_tree_block_key(rc, block);
2439 rb_node = rb_next(rb_node);
2440 }
2441
2442 rb_node = rb_first(blocks);
2443 while (rb_node) {
2444 block = rb_entry(rb_node, struct tree_block, rb_node);
2445
2446 node = build_backref_tree(rc, cache, &block->key,
2447 block->level, block->bytenr);
2448 if (IS_ERR(node)) {
2449 err = PTR_ERR(node);
2450 goto out;
2451 }
2452
2453 ret = relocate_tree_block(trans, rc, node, &block->key,
2454 path);
2455 if (ret < 0) {
2456 err = ret;
2457 goto out;
2458 }
2459 remove_backref_node(cache, node);
2460 rb_node = rb_next(rb_node);
2461 }
2462
2463 if (level > 0)
2464 goto out;
2465
2466 free_block_list(blocks);
2467
2468 /*
2469 * now backrefs of some upper level tree blocks have been cached,
2470 * try relocating blocks referenced by these upper level blocks.
2471 */
2472 while (1) {
2473 struct backref_node *upper = NULL;
2474 if (trans->transaction->in_commit ||
2475 trans->transaction->delayed_refs.flushing)
2476 break;
2477
2478 ret = add_adjacent_blocks(trans, rc, cache, blocks, level,
2479 &upper);
2480 if (ret < 0)
2481 err = ret;
2482 if (ret != 0)
2483 break;
2484
2485 rb_node = rb_first(blocks);
2486 while (rb_node) {
2487 block = rb_entry(rb_node, struct tree_block, rb_node);
2488 if (trans->transaction->in_commit ||
2489 trans->transaction->delayed_refs.flushing)
2490 goto out;
2491 BUG_ON(!block->key_ready);
2492 node = build_backref_tree(rc, cache, &block->key,
2493 level, block->bytenr);
2494 if (IS_ERR(node)) {
2495 err = PTR_ERR(node);
2496 goto out;
2497 }
2498
2499 ret = relocate_tree_block(trans, rc, node,
2500 &block->key, path);
2501 if (ret < 0) {
2502 err = ret;
2503 goto out;
2504 }
2505 remove_backref_node(cache, node);
2506 rb_node = rb_next(rb_node);
2507 }
2508 free_block_list(blocks);
2509
2510 if (upper) {
2511 ret = link_to_upper(trans, upper, path);
2512 if (ret < 0) {
2513 err = ret;
2514 break;
2515 }
2516 remove_backref_node(cache, upper);
2517 }
2518 }
2519 out:
2520 free_block_list(blocks);
2521
2522 ret = finish_pending_nodes(trans, cache, path);
2523 if (ret < 0)
2524 err = ret;
2525
2526 kfree(cache);
2527 btrfs_free_path(path);
2528 return err;
2529 }
2530
2531 static noinline_for_stack
2532 int relocate_inode_pages(struct inode *inode, u64 start, u64 len)
2533 {
2534 u64 page_start;
2535 u64 page_end;
2536 unsigned long i;
2537 unsigned long first_index;
2538 unsigned long last_index;
2539 unsigned int total_read = 0;
2540 unsigned int total_dirty = 0;
2541 struct page *page;
2542 struct file_ra_state *ra;
2543 struct btrfs_ordered_extent *ordered;
2544 struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
2545 int ret = 0;
2546
2547 ra = kzalloc(sizeof(*ra), GFP_NOFS);
2548 if (!ra)
2549 return -ENOMEM;
2550
2551 mutex_lock(&inode->i_mutex);
2552 first_index = start >> PAGE_CACHE_SHIFT;
2553 last_index = (start + len - 1) >> PAGE_CACHE_SHIFT;
2554
2555 /* make sure the dirty trick played by the caller work */
2556 ret = invalidate_inode_pages2_range(inode->i_mapping,
2557 first_index, last_index);
2558 if (ret)
2559 goto out_unlock;
2560
2561 file_ra_state_init(ra, inode->i_mapping);
2562
2563 for (i = first_index ; i <= last_index; i++) {
2564 if (total_read % ra->ra_pages == 0) {
2565 btrfs_force_ra(inode->i_mapping, ra, NULL, i,
2566 min(last_index, ra->ra_pages + i - 1));
2567 }
2568 total_read++;
2569 again:
2570 if (((u64)i << PAGE_CACHE_SHIFT) > i_size_read(inode))
2571 BUG_ON(1);
2572 page = grab_cache_page(inode->i_mapping, i);
2573 if (!page) {
2574 ret = -ENOMEM;
2575 goto out_unlock;
2576 }
2577 if (!PageUptodate(page)) {
2578 btrfs_readpage(NULL, page);
2579 lock_page(page);
2580 if (!PageUptodate(page)) {
2581 unlock_page(page);
2582 page_cache_release(page);
2583 ret = -EIO;
2584 goto out_unlock;
2585 }
2586 }
2587 wait_on_page_writeback(page);
2588
2589 page_start = (u64)page->index << PAGE_CACHE_SHIFT;
2590 page_end = page_start + PAGE_CACHE_SIZE - 1;
2591 lock_extent(io_tree, page_start, page_end, GFP_NOFS);
2592
2593 ordered = btrfs_lookup_ordered_extent(inode, page_start);
2594 if (ordered) {
2595 unlock_extent(io_tree, page_start, page_end, GFP_NOFS);
2596 unlock_page(page);
2597 page_cache_release(page);
2598 btrfs_start_ordered_extent(inode, ordered, 1);
2599 btrfs_put_ordered_extent(ordered);
2600 goto again;
2601 }
2602 set_page_extent_mapped(page);
2603
2604 if (i == first_index)
2605 set_extent_bits(io_tree, page_start, page_end,
2606 EXTENT_BOUNDARY, GFP_NOFS);
2607 btrfs_set_extent_delalloc(inode, page_start, page_end);
2608
2609 set_page_dirty(page);
2610 total_dirty++;
2611
2612 unlock_extent(io_tree, page_start, page_end, GFP_NOFS);
2613 unlock_page(page);
2614 page_cache_release(page);
2615 }
2616 out_unlock:
2617 mutex_unlock(&inode->i_mutex);
2618 kfree(ra);
2619 balance_dirty_pages_ratelimited_nr(inode->i_mapping, total_dirty);
2620 return ret;
2621 }
2622
2623 static noinline_for_stack
2624 int relocate_data_extent(struct inode *inode, struct btrfs_key *extent_key)
2625 {
2626 struct btrfs_root *root = BTRFS_I(inode)->root;
2627 struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
2628 struct extent_map *em;
2629 u64 start = extent_key->objectid - BTRFS_I(inode)->index_cnt;
2630 u64 end = start + extent_key->offset - 1;
2631
2632 em = alloc_extent_map(GFP_NOFS);
2633 em->start = start;
2634 em->len = extent_key->offset;
2635 em->block_len = extent_key->offset;
2636 em->block_start = extent_key->objectid;
2637 em->bdev = root->fs_info->fs_devices->latest_bdev;
2638 set_bit(EXTENT_FLAG_PINNED, &em->flags);
2639
2640 /* setup extent map to cheat btrfs_readpage */
2641 lock_extent(&BTRFS_I(inode)->io_tree, start, end, GFP_NOFS);
2642 while (1) {
2643 int ret;
2644 spin_lock(&em_tree->lock);
2645 ret = add_extent_mapping(em_tree, em);
2646 spin_unlock(&em_tree->lock);
2647 if (ret != -EEXIST) {
2648 free_extent_map(em);
2649 break;
2650 }
2651 btrfs_drop_extent_cache(inode, start, end, 0);
2652 }
2653 unlock_extent(&BTRFS_I(inode)->io_tree, start, end, GFP_NOFS);
2654
2655 return relocate_inode_pages(inode, start, extent_key->offset);
2656 }
2657
2658 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
2659 static int get_ref_objectid_v0(struct reloc_control *rc,
2660 struct btrfs_path *path,
2661 struct btrfs_key *extent_key,
2662 u64 *ref_objectid, int *path_change)
2663 {
2664 struct btrfs_key key;
2665 struct extent_buffer *leaf;
2666 struct btrfs_extent_ref_v0 *ref0;
2667 int ret;
2668 int slot;
2669
2670 leaf = path->nodes[0];
2671 slot = path->slots[0];
2672 while (1) {
2673 if (slot >= btrfs_header_nritems(leaf)) {
2674 ret = btrfs_next_leaf(rc->extent_root, path);
2675 if (ret < 0)
2676 return ret;
2677 BUG_ON(ret > 0);
2678 leaf = path->nodes[0];
2679 slot = path->slots[0];
2680 if (path_change)
2681 *path_change = 1;
2682 }
2683 btrfs_item_key_to_cpu(leaf, &key, slot);
2684 if (key.objectid != extent_key->objectid)
2685 return -ENOENT;
2686
2687 if (key.type != BTRFS_EXTENT_REF_V0_KEY) {
2688 slot++;
2689 continue;
2690 }
2691 ref0 = btrfs_item_ptr(leaf, slot,
2692 struct btrfs_extent_ref_v0);
2693 *ref_objectid = btrfs_ref_objectid_v0(leaf, ref0);
2694 break;
2695 }
2696 return 0;
2697 }
2698 #endif
2699
2700 /*
2701 * helper to add a tree block to the list.
2702 * the major work is getting the generation and level of the block
2703 */
2704 static int add_tree_block(struct reloc_control *rc,
2705 struct btrfs_key *extent_key,
2706 struct btrfs_path *path,
2707 struct rb_root *blocks)
2708 {
2709 struct extent_buffer *eb;
2710 struct btrfs_extent_item *ei;
2711 struct btrfs_tree_block_info *bi;
2712 struct tree_block *block;
2713 struct rb_node *rb_node;
2714 u32 item_size;
2715 int level = -1;
2716 int generation;
2717
2718 eb = path->nodes[0];
2719 item_size = btrfs_item_size_nr(eb, path->slots[0]);
2720
2721 if (item_size >= sizeof(*ei) + sizeof(*bi)) {
2722 ei = btrfs_item_ptr(eb, path->slots[0],
2723 struct btrfs_extent_item);
2724 bi = (struct btrfs_tree_block_info *)(ei + 1);
2725 generation = btrfs_extent_generation(eb, ei);
2726 level = btrfs_tree_block_level(eb, bi);
2727 } else {
2728 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
2729 u64 ref_owner;
2730 int ret;
2731
2732 BUG_ON(item_size != sizeof(struct btrfs_extent_item_v0));
2733 ret = get_ref_objectid_v0(rc, path, extent_key,
2734 &ref_owner, NULL);
2735 BUG_ON(ref_owner >= BTRFS_MAX_LEVEL);
2736 level = (int)ref_owner;
2737 /* FIXME: get real generation */
2738 generation = 0;
2739 #else
2740 BUG();
2741 #endif
2742 }
2743
2744 btrfs_release_path(rc->extent_root, path);
2745
2746 BUG_ON(level == -1);
2747
2748 block = kmalloc(sizeof(*block), GFP_NOFS);
2749 if (!block)
2750 return -ENOMEM;
2751
2752 block->bytenr = extent_key->objectid;
2753 block->key.objectid = extent_key->offset;
2754 block->key.offset = generation;
2755 block->level = level;
2756 block->key_ready = 0;
2757
2758 rb_node = tree_insert(blocks, block->bytenr, &block->rb_node);
2759 BUG_ON(rb_node);
2760
2761 return 0;
2762 }
2763
2764 /*
2765 * helper to add tree blocks for backref of type BTRFS_SHARED_DATA_REF_KEY
2766 */
2767 static int __add_tree_block(struct reloc_control *rc,
2768 u64 bytenr, u32 blocksize,
2769 struct rb_root *blocks)
2770 {
2771 struct btrfs_path *path;
2772 struct btrfs_key key;
2773 int ret;
2774
2775 if (tree_block_processed(bytenr, blocksize, rc))
2776 return 0;
2777
2778 if (tree_search(blocks, bytenr))
2779 return 0;
2780
2781 path = btrfs_alloc_path();
2782 if (!path)
2783 return -ENOMEM;
2784
2785 key.objectid = bytenr;
2786 key.type = BTRFS_EXTENT_ITEM_KEY;
2787 key.offset = blocksize;
2788
2789 path->search_commit_root = 1;
2790 path->skip_locking = 1;
2791 ret = btrfs_search_slot(NULL, rc->extent_root, &key, path, 0, 0);
2792 if (ret < 0)
2793 goto out;
2794 BUG_ON(ret);
2795
2796 btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
2797 ret = add_tree_block(rc, &key, path, blocks);
2798 out:
2799 btrfs_free_path(path);
2800 return ret;
2801 }
2802
2803 /*
2804 * helper to check if the block use full backrefs for pointers in it
2805 */
2806 static int block_use_full_backref(struct reloc_control *rc,
2807 struct extent_buffer *eb)
2808 {
2809 struct btrfs_path *path;
2810 struct btrfs_extent_item *ei;
2811 struct btrfs_key key;
2812 u64 flags;
2813 int ret;
2814
2815 if (btrfs_header_flag(eb, BTRFS_HEADER_FLAG_RELOC) ||
2816 btrfs_header_backref_rev(eb) < BTRFS_MIXED_BACKREF_REV)
2817 return 1;
2818
2819 path = btrfs_alloc_path();
2820 BUG_ON(!path);
2821
2822 key.objectid = eb->start;
2823 key.type = BTRFS_EXTENT_ITEM_KEY;
2824 key.offset = eb->len;
2825
2826 path->search_commit_root = 1;
2827 path->skip_locking = 1;
2828 ret = btrfs_search_slot(NULL, rc->extent_root,
2829 &key, path, 0, 0);
2830 BUG_ON(ret);
2831
2832 ei = btrfs_item_ptr(path->nodes[0], path->slots[0],
2833 struct btrfs_extent_item);
2834 flags = btrfs_extent_flags(path->nodes[0], ei);
2835 BUG_ON(!(flags & BTRFS_EXTENT_FLAG_TREE_BLOCK));
2836 if (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF)
2837 ret = 1;
2838 else
2839 ret = 0;
2840 btrfs_free_path(path);
2841 return ret;
2842 }
2843
2844 /*
2845 * helper to add tree blocks for backref of type BTRFS_EXTENT_DATA_REF_KEY
2846 * this function scans fs tree to find blocks reference the data extent
2847 */
2848 static int find_data_references(struct reloc_control *rc,
2849 struct btrfs_key *extent_key,
2850 struct extent_buffer *leaf,
2851 struct btrfs_extent_data_ref *ref,
2852 struct rb_root *blocks)
2853 {
2854 struct btrfs_path *path;
2855 struct tree_block *block;
2856 struct btrfs_root *root;
2857 struct btrfs_file_extent_item *fi;
2858 struct rb_node *rb_node;
2859 struct btrfs_key key;
2860 u64 ref_root;
2861 u64 ref_objectid;
2862 u64 ref_offset;
2863 u32 ref_count;
2864 u32 nritems;
2865 int err = 0;
2866 int added = 0;
2867 int counted;
2868 int ret;
2869
2870 path = btrfs_alloc_path();
2871 if (!path)
2872 return -ENOMEM;
2873
2874 ref_root = btrfs_extent_data_ref_root(leaf, ref);
2875 ref_objectid = btrfs_extent_data_ref_objectid(leaf, ref);
2876 ref_offset = btrfs_extent_data_ref_offset(leaf, ref);
2877 ref_count = btrfs_extent_data_ref_count(leaf, ref);
2878
2879 root = read_fs_root(rc->extent_root->fs_info, ref_root);
2880 if (IS_ERR(root)) {
2881 err = PTR_ERR(root);
2882 goto out;
2883 }
2884
2885 key.objectid = ref_objectid;
2886 key.offset = ref_offset;
2887 key.type = BTRFS_EXTENT_DATA_KEY;
2888
2889 path->search_commit_root = 1;
2890 path->skip_locking = 1;
2891 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
2892 if (ret < 0) {
2893 err = ret;
2894 goto out;
2895 }
2896
2897 leaf = path->nodes[0];
2898 nritems = btrfs_header_nritems(leaf);
2899 /*
2900 * the references in tree blocks that use full backrefs
2901 * are not counted in
2902 */
2903 if (block_use_full_backref(rc, leaf))
2904 counted = 0;
2905 else
2906 counted = 1;
2907 rb_node = tree_search(blocks, leaf->start);
2908 if (rb_node) {
2909 if (counted)
2910 added = 1;
2911 else
2912 path->slots[0] = nritems;
2913 }
2914
2915 while (ref_count > 0) {
2916 while (path->slots[0] >= nritems) {
2917 ret = btrfs_next_leaf(root, path);
2918 if (ret < 0) {
2919 err = ret;
2920 goto out;
2921 }
2922 if (ret > 0) {
2923 WARN_ON(1);
2924 goto out;
2925 }
2926
2927 leaf = path->nodes[0];
2928 nritems = btrfs_header_nritems(leaf);
2929 added = 0;
2930
2931 if (block_use_full_backref(rc, leaf))
2932 counted = 0;
2933 else
2934 counted = 1;
2935 rb_node = tree_search(blocks, leaf->start);
2936 if (rb_node) {
2937 if (counted)
2938 added = 1;
2939 else
2940 path->slots[0] = nritems;
2941 }
2942 }
2943
2944 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
2945 if (key.objectid != ref_objectid ||
2946 key.type != BTRFS_EXTENT_DATA_KEY) {
2947 WARN_ON(1);
2948 break;
2949 }
2950
2951 fi = btrfs_item_ptr(leaf, path->slots[0],
2952 struct btrfs_file_extent_item);
2953
2954 if (btrfs_file_extent_type(leaf, fi) ==
2955 BTRFS_FILE_EXTENT_INLINE)
2956 goto next;
2957
2958 if (btrfs_file_extent_disk_bytenr(leaf, fi) !=
2959 extent_key->objectid)
2960 goto next;
2961
2962 key.offset -= btrfs_file_extent_offset(leaf, fi);
2963 if (key.offset != ref_offset)
2964 goto next;
2965
2966 if (counted)
2967 ref_count--;
2968 if (added)
2969 goto next;
2970
2971 if (!tree_block_processed(leaf->start, leaf->len, rc)) {
2972 block = kmalloc(sizeof(*block), GFP_NOFS);
2973 if (!block) {
2974 err = -ENOMEM;
2975 break;
2976 }
2977 block->bytenr = leaf->start;
2978 btrfs_item_key_to_cpu(leaf, &block->key, 0);
2979 block->level = 0;
2980 block->key_ready = 1;
2981 rb_node = tree_insert(blocks, block->bytenr,
2982 &block->rb_node);
2983 BUG_ON(rb_node);
2984 }
2985 if (counted)
2986 added = 1;
2987 else
2988 path->slots[0] = nritems;
2989 next:
2990 path->slots[0]++;
2991
2992 }
2993 out:
2994 btrfs_free_path(path);
2995 return err;
2996 }
2997
2998 /*
2999 * hepler to find all tree blocks that reference a given data extent
3000 */
3001 static noinline_for_stack
3002 int add_data_references(struct reloc_control *rc,
3003 struct btrfs_key *extent_key,
3004 struct btrfs_path *path,
3005 struct rb_root *blocks)
3006 {
3007 struct btrfs_key key;
3008 struct extent_buffer *eb;
3009 struct btrfs_extent_data_ref *dref;
3010 struct btrfs_extent_inline_ref *iref;
3011 unsigned long ptr;
3012 unsigned long end;
3013 u32 blocksize;
3014 int ret;
3015 int err = 0;
3016
3017 ret = get_new_location(rc->data_inode, NULL, extent_key->objectid,
3018 extent_key->offset);
3019 BUG_ON(ret < 0);
3020 if (ret > 0) {
3021 /* the relocated data is fragmented */
3022 rc->extents_skipped++;
3023 btrfs_release_path(rc->extent_root, path);
3024 return 0;
3025 }
3026
3027 blocksize = btrfs_level_size(rc->extent_root, 0);
3028
3029 eb = path->nodes[0];
3030 ptr = btrfs_item_ptr_offset(eb, path->slots[0]);
3031 end = ptr + btrfs_item_size_nr(eb, path->slots[0]);
3032 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
3033 if (ptr + sizeof(struct btrfs_extent_item_v0) == end)
3034 ptr = end;
3035 else
3036 #endif
3037 ptr += sizeof(struct btrfs_extent_item);
3038
3039 while (ptr < end) {
3040 iref = (struct btrfs_extent_inline_ref *)ptr;
3041 key.type = btrfs_extent_inline_ref_type(eb, iref);
3042 if (key.type == BTRFS_SHARED_DATA_REF_KEY) {
3043 key.offset = btrfs_extent_inline_ref_offset(eb, iref);
3044 ret = __add_tree_block(rc, key.offset, blocksize,
3045 blocks);
3046 } else if (key.type == BTRFS_EXTENT_DATA_REF_KEY) {
3047 dref = (struct btrfs_extent_data_ref *)(&iref->offset);
3048 ret = find_data_references(rc, extent_key,
3049 eb, dref, blocks);
3050 } else {
3051 BUG();
3052 }
3053 ptr += btrfs_extent_inline_ref_size(key.type);
3054 }
3055 WARN_ON(ptr > end);
3056
3057 while (1) {
3058 cond_resched();
3059 eb = path->nodes[0];
3060 if (path->slots[0] >= btrfs_header_nritems(eb)) {
3061 ret = btrfs_next_leaf(rc->extent_root, path);
3062 if (ret < 0) {
3063 err = ret;
3064 break;
3065 }
3066 if (ret > 0)
3067 break;
3068 eb = path->nodes[0];
3069 }
3070
3071 btrfs_item_key_to_cpu(eb, &key, path->slots[0]);
3072 if (key.objectid != extent_key->objectid)
3073 break;
3074
3075 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
3076 if (key.type == BTRFS_SHARED_DATA_REF_KEY ||
3077 key.type == BTRFS_EXTENT_REF_V0_KEY) {
3078 #else
3079 BUG_ON(key.type == BTRFS_EXTENT_REF_V0_KEY);
3080 if (key.type == BTRFS_SHARED_DATA_REF_KEY) {
3081 #endif
3082 ret = __add_tree_block(rc, key.offset, blocksize,
3083 blocks);
3084 } else if (key.type == BTRFS_EXTENT_DATA_REF_KEY) {
3085 dref = btrfs_item_ptr(eb, path->slots[0],
3086 struct btrfs_extent_data_ref);
3087 ret = find_data_references(rc, extent_key,
3088 eb, dref, blocks);
3089 } else {
3090 ret = 0;
3091 }
3092 if (ret) {
3093 err = ret;
3094 break;
3095 }
3096 path->slots[0]++;
3097 }
3098 btrfs_release_path(rc->extent_root, path);
3099 if (err)
3100 free_block_list(blocks);
3101 return err;
3102 }
3103
3104 /*
3105 * hepler to find next unprocessed extent
3106 */
3107 static noinline_for_stack
3108 int find_next_extent(struct btrfs_trans_handle *trans,
3109 struct reloc_control *rc, struct btrfs_path *path)
3110 {
3111 struct btrfs_key key;
3112 struct extent_buffer *leaf;
3113 u64 start, end, last;
3114 int ret;
3115
3116 last = rc->block_group->key.objectid + rc->block_group->key.offset;
3117 while (1) {
3118 cond_resched();
3119 if (rc->search_start >= last) {
3120 ret = 1;
3121 break;
3122 }
3123
3124 key.objectid = rc->search_start;
3125 key.type = BTRFS_EXTENT_ITEM_KEY;
3126 key.offset = 0;
3127
3128 path->search_commit_root = 1;
3129 path->skip_locking = 1;
3130 ret = btrfs_search_slot(NULL, rc->extent_root, &key, path,
3131 0, 0);
3132 if (ret < 0)
3133 break;
3134 next:
3135 leaf = path->nodes[0];
3136 if (path->slots[0] >= btrfs_header_nritems(leaf)) {
3137 ret = btrfs_next_leaf(rc->extent_root, path);
3138 if (ret != 0)
3139 break;
3140 leaf = path->nodes[0];
3141 }
3142
3143 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
3144 if (key.objectid >= last) {
3145 ret = 1;
3146 break;
3147 }
3148
3149 if (key.type != BTRFS_EXTENT_ITEM_KEY ||
3150 key.objectid + key.offset <= rc->search_start) {
3151 path->slots[0]++;
3152 goto next;
3153 }
3154
3155 ret = find_first_extent_bit(&rc->processed_blocks,
3156 key.objectid, &start, &end,
3157 EXTENT_DIRTY);
3158
3159 if (ret == 0 && start <= key.objectid) {
3160 btrfs_release_path(rc->extent_root, path);
3161 rc->search_start = end + 1;
3162 } else {
3163 rc->search_start = key.objectid + key.offset;
3164 return 0;
3165 }
3166 }
3167 btrfs_release_path(rc->extent_root, path);
3168 return ret;
3169 }
3170
3171 static void set_reloc_control(struct reloc_control *rc)
3172 {
3173 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
3174 mutex_lock(&fs_info->trans_mutex);
3175 fs_info->reloc_ctl = rc;
3176 mutex_unlock(&fs_info->trans_mutex);
3177 }
3178
3179 static void unset_reloc_control(struct reloc_control *rc)
3180 {
3181 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
3182 mutex_lock(&fs_info->trans_mutex);
3183 fs_info->reloc_ctl = NULL;
3184 mutex_unlock(&fs_info->trans_mutex);
3185 }
3186
3187 static int check_extent_flags(u64 flags)
3188 {
3189 if ((flags & BTRFS_EXTENT_FLAG_DATA) &&
3190 (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK))
3191 return 1;
3192 if (!(flags & BTRFS_EXTENT_FLAG_DATA) &&
3193 !(flags & BTRFS_EXTENT_FLAG_TREE_BLOCK))
3194 return 1;
3195 if ((flags & BTRFS_EXTENT_FLAG_DATA) &&
3196 (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF))
3197 return 1;
3198 return 0;
3199 }
3200
3201 static noinline_for_stack int relocate_block_group(struct reloc_control *rc)
3202 {
3203 struct rb_root blocks = RB_ROOT;
3204 struct btrfs_key key;
3205 struct btrfs_trans_handle *trans = NULL;
3206 struct btrfs_path *path;
3207 struct btrfs_extent_item *ei;
3208 unsigned long nr;
3209 u64 flags;
3210 u32 item_size;
3211 int ret;
3212 int err = 0;
3213
3214 path = btrfs_alloc_path();
3215 if (!path)
3216 return -ENOMEM;
3217
3218 rc->search_start = rc->block_group->key.objectid;
3219 clear_extent_bits(&rc->processed_blocks, 0, (u64)-1, EXTENT_DIRTY,
3220 GFP_NOFS);
3221
3222 rc->create_reloc_root = 1;
3223 set_reloc_control(rc);
3224
3225 trans = btrfs_start_transaction(rc->extent_root, 1);
3226 btrfs_commit_transaction(trans, rc->extent_root);
3227
3228 while (1) {
3229 trans = btrfs_start_transaction(rc->extent_root, 1);
3230
3231 ret = find_next_extent(trans, rc, path);
3232 if (ret < 0)
3233 err = ret;
3234 if (ret != 0)
3235 break;
3236
3237 rc->extents_found++;
3238
3239 ei = btrfs_item_ptr(path->nodes[0], path->slots[0],
3240 struct btrfs_extent_item);
3241 btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
3242 item_size = btrfs_item_size_nr(path->nodes[0],
3243 path->slots[0]);
3244 if (item_size >= sizeof(*ei)) {
3245 flags = btrfs_extent_flags(path->nodes[0], ei);
3246 ret = check_extent_flags(flags);
3247 BUG_ON(ret);
3248
3249 } else {
3250 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
3251 u64 ref_owner;
3252 int path_change = 0;
3253
3254 BUG_ON(item_size !=
3255 sizeof(struct btrfs_extent_item_v0));
3256 ret = get_ref_objectid_v0(rc, path, &key, &ref_owner,
3257 &path_change);
3258 if (ref_owner < BTRFS_FIRST_FREE_OBJECTID)
3259 flags = BTRFS_EXTENT_FLAG_TREE_BLOCK;
3260 else
3261 flags = BTRFS_EXTENT_FLAG_DATA;
3262
3263 if (path_change) {
3264 btrfs_release_path(rc->extent_root, path);
3265
3266 path->search_commit_root = 1;
3267 path->skip_locking = 1;
3268 ret = btrfs_search_slot(NULL, rc->extent_root,
3269 &key, path, 0, 0);
3270 if (ret < 0) {
3271 err = ret;
3272 break;
3273 }
3274 BUG_ON(ret > 0);
3275 }
3276 #else
3277 BUG();
3278 #endif
3279 }
3280
3281 if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) {
3282 ret = add_tree_block(rc, &key, path, &blocks);
3283 } else if (rc->stage == UPDATE_DATA_PTRS &&
3284 (flags & BTRFS_EXTENT_FLAG_DATA)) {
3285 ret = add_data_references(rc, &key, path, &blocks);
3286 } else {
3287 btrfs_release_path(rc->extent_root, path);
3288 ret = 0;
3289 }
3290 if (ret < 0) {
3291 err = 0;
3292 break;
3293 }
3294
3295 if (!RB_EMPTY_ROOT(&blocks)) {
3296 ret = relocate_tree_blocks(trans, rc, &blocks);
3297 if (ret < 0) {
3298 err = ret;
3299 break;
3300 }
3301 }
3302
3303 nr = trans->blocks_used;
3304 btrfs_end_transaction_throttle(trans, rc->extent_root);
3305 trans = NULL;
3306 btrfs_btree_balance_dirty(rc->extent_root, nr);
3307
3308 if (rc->stage == MOVE_DATA_EXTENTS &&
3309 (flags & BTRFS_EXTENT_FLAG_DATA)) {
3310 rc->found_file_extent = 1;
3311 ret = relocate_data_extent(rc->data_inode, &key);
3312 if (ret < 0) {
3313 err = ret;
3314 break;
3315 }
3316 }
3317 }
3318 btrfs_free_path(path);
3319
3320 if (trans) {
3321 nr = trans->blocks_used;
3322 btrfs_end_transaction(trans, rc->extent_root);
3323 btrfs_btree_balance_dirty(rc->extent_root, nr);
3324 }
3325
3326 rc->create_reloc_root = 0;
3327 smp_mb();
3328
3329 if (rc->extents_found > 0) {
3330 trans = btrfs_start_transaction(rc->extent_root, 1);
3331 btrfs_commit_transaction(trans, rc->extent_root);
3332 }
3333
3334 merge_reloc_roots(rc);
3335
3336 unset_reloc_control(rc);
3337
3338 /* get rid of pinned extents */
3339 trans = btrfs_start_transaction(rc->extent_root, 1);
3340 btrfs_commit_transaction(trans, rc->extent_root);
3341
3342 return err;
3343 }
3344
3345 static int __insert_orphan_inode(struct btrfs_trans_handle *trans,
3346 struct btrfs_root *root,
3347 u64 objectid, u64 size)
3348 {
3349 struct btrfs_path *path;
3350 struct btrfs_inode_item *item;
3351 struct extent_buffer *leaf;
3352 int ret;
3353
3354 path = btrfs_alloc_path();
3355 if (!path)
3356 return -ENOMEM;
3357
3358 ret = btrfs_insert_empty_inode(trans, root, path, objectid);
3359 if (ret)
3360 goto out;
3361
3362 leaf = path->nodes[0];
3363 item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_inode_item);
3364 memset_extent_buffer(leaf, 0, (unsigned long)item, sizeof(*item));
3365 btrfs_set_inode_generation(leaf, item, 1);
3366 btrfs_set_inode_size(leaf, item, size);
3367 btrfs_set_inode_mode(leaf, item, S_IFREG | 0600);
3368 btrfs_set_inode_flags(leaf, item, BTRFS_INODE_NOCOMPRESS);
3369 btrfs_mark_buffer_dirty(leaf);
3370 btrfs_release_path(root, path);
3371 out:
3372 btrfs_free_path(path);
3373 return ret;
3374 }
3375
3376 /*
3377 * helper to create inode for data relocation.
3378 * the inode is in data relocation tree and its link count is 0
3379 */
3380 static struct inode *create_reloc_inode(struct btrfs_fs_info *fs_info,
3381 struct btrfs_block_group_cache *group)
3382 {
3383 struct inode *inode = NULL;
3384 struct btrfs_trans_handle *trans;
3385 struct btrfs_root *root;
3386 struct btrfs_key key;
3387 unsigned long nr;
3388 u64 objectid = BTRFS_FIRST_FREE_OBJECTID;
3389 int err = 0;
3390
3391 root = read_fs_root(fs_info, BTRFS_DATA_RELOC_TREE_OBJECTID);
3392 if (IS_ERR(root))
3393 return ERR_CAST(root);
3394
3395 trans = btrfs_start_transaction(root, 1);
3396 BUG_ON(!trans);
3397
3398 err = btrfs_find_free_objectid(trans, root, objectid, &objectid);
3399 if (err)
3400 goto out;
3401
3402 err = __insert_orphan_inode(trans, root, objectid, group->key.offset);
3403 BUG_ON(err);
3404
3405 err = btrfs_insert_file_extent(trans, root, objectid, 0, 0, 0,
3406 group->key.offset, 0, group->key.offset,
3407 0, 0, 0);
3408 BUG_ON(err);
3409
3410 key.objectid = objectid;
3411 key.type = BTRFS_INODE_ITEM_KEY;
3412 key.offset = 0;
3413 inode = btrfs_iget(root->fs_info->sb, &key, root);
3414 BUG_ON(IS_ERR(inode) || is_bad_inode(inode));
3415 BTRFS_I(inode)->index_cnt = group->key.objectid;
3416
3417 err = btrfs_orphan_add(trans, inode);
3418 out:
3419 nr = trans->blocks_used;
3420 btrfs_end_transaction(trans, root);
3421
3422 btrfs_btree_balance_dirty(root, nr);
3423 if (err) {
3424 if (inode)
3425 iput(inode);
3426 inode = ERR_PTR(err);
3427 }
3428 return inode;
3429 }
3430
3431 /*
3432 * function to relocate all extents in a block group.
3433 */
3434 int btrfs_relocate_block_group(struct btrfs_root *extent_root, u64 group_start)
3435 {
3436 struct btrfs_fs_info *fs_info = extent_root->fs_info;
3437 struct reloc_control *rc;
3438 int ret;
3439 int err = 0;
3440
3441 rc = kzalloc(sizeof(*rc), GFP_NOFS);
3442 if (!rc)
3443 return -ENOMEM;
3444
3445 mapping_tree_init(&rc->reloc_root_tree);
3446 extent_io_tree_init(&rc->processed_blocks, NULL, GFP_NOFS);
3447 INIT_LIST_HEAD(&rc->reloc_roots);
3448
3449 rc->block_group = btrfs_lookup_block_group(fs_info, group_start);
3450 BUG_ON(!rc->block_group);
3451
3452 btrfs_init_workers(&rc->workers, "relocate",
3453 fs_info->thread_pool_size);
3454
3455 rc->extent_root = extent_root;
3456 btrfs_prepare_block_group_relocation(extent_root, rc->block_group);
3457
3458 rc->data_inode = create_reloc_inode(fs_info, rc->block_group);
3459 if (IS_ERR(rc->data_inode)) {
3460 err = PTR_ERR(rc->data_inode);
3461 rc->data_inode = NULL;
3462 goto out;
3463 }
3464
3465 printk(KERN_INFO "btrfs: relocating block group %llu flags %llu\n",
3466 (unsigned long long)rc->block_group->key.objectid,
3467 (unsigned long long)rc->block_group->flags);
3468
3469 btrfs_start_delalloc_inodes(fs_info->tree_root);
3470 btrfs_wait_ordered_extents(fs_info->tree_root, 0);
3471
3472 while (1) {
3473 mutex_lock(&fs_info->cleaner_mutex);
3474 btrfs_clean_old_snapshots(fs_info->tree_root);
3475 mutex_unlock(&fs_info->cleaner_mutex);
3476
3477 rc->extents_found = 0;
3478 rc->extents_skipped = 0;
3479
3480 ret = relocate_block_group(rc);
3481 if (ret < 0) {
3482 err = ret;
3483 break;
3484 }
3485
3486 if (rc->extents_found == 0)
3487 break;
3488
3489 printk(KERN_INFO "btrfs: found %llu extents\n",
3490 (unsigned long long)rc->extents_found);
3491
3492 if (rc->stage == MOVE_DATA_EXTENTS && rc->found_file_extent) {
3493 btrfs_wait_ordered_range(rc->data_inode, 0, (u64)-1);
3494 invalidate_mapping_pages(rc->data_inode->i_mapping,
3495 0, -1);
3496 rc->stage = UPDATE_DATA_PTRS;
3497 } else if (rc->stage == UPDATE_DATA_PTRS &&
3498 rc->extents_skipped >= rc->extents_found) {
3499 iput(rc->data_inode);
3500 rc->data_inode = create_reloc_inode(fs_info,
3501 rc->block_group);
3502 if (IS_ERR(rc->data_inode)) {
3503 err = PTR_ERR(rc->data_inode);
3504 rc->data_inode = NULL;
3505 break;
3506 }
3507 rc->stage = MOVE_DATA_EXTENTS;
3508 rc->found_file_extent = 0;
3509 }
3510 }
3511
3512 filemap_fdatawrite_range(fs_info->btree_inode->i_mapping,
3513 rc->block_group->key.objectid,
3514 rc->block_group->key.objectid +
3515 rc->block_group->key.offset - 1);
3516
3517 WARN_ON(rc->block_group->pinned > 0);
3518 WARN_ON(rc->block_group->reserved > 0);
3519 WARN_ON(btrfs_block_group_used(&rc->block_group->item) > 0);
3520 out:
3521 iput(rc->data_inode);
3522 btrfs_stop_workers(&rc->workers);
3523 btrfs_put_block_group(rc->block_group);
3524 kfree(rc);
3525 return err;
3526 }
3527
3528 /*
3529 * recover relocation interrupted by system crash.
3530 *
3531 * this function resumes merging reloc trees with corresponding fs trees.
3532 * this is important for keeping the sharing of tree blocks
3533 */
3534 int btrfs_recover_relocation(struct btrfs_root *root)
3535 {
3536 LIST_HEAD(reloc_roots);
3537 struct btrfs_key key;
3538 struct btrfs_root *fs_root;
3539 struct btrfs_root *reloc_root;
3540 struct btrfs_path *path;
3541 struct extent_buffer *leaf;
3542 struct reloc_control *rc = NULL;
3543 struct btrfs_trans_handle *trans;
3544 int ret;
3545 int err = 0;
3546
3547 path = btrfs_alloc_path();
3548 if (!path)
3549 return -ENOMEM;
3550
3551 key.objectid = BTRFS_TREE_RELOC_OBJECTID;
3552 key.type = BTRFS_ROOT_ITEM_KEY;
3553 key.offset = (u64)-1;
3554
3555 while (1) {
3556 ret = btrfs_search_slot(NULL, root->fs_info->tree_root, &key,
3557 path, 0, 0);
3558 if (ret < 0) {
3559 err = ret;
3560 goto out;
3561 }
3562 if (ret > 0) {
3563 if (path->slots[0] == 0)
3564 break;
3565 path->slots[0]--;
3566 }
3567 leaf = path->nodes[0];
3568 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
3569 btrfs_release_path(root->fs_info->tree_root, path);
3570
3571 if (key.objectid != BTRFS_TREE_RELOC_OBJECTID ||
3572 key.type != BTRFS_ROOT_ITEM_KEY)
3573 break;
3574
3575 reloc_root = btrfs_read_fs_root_no_radix(root, &key);
3576 if (IS_ERR(reloc_root)) {
3577 err = PTR_ERR(reloc_root);
3578 goto out;
3579 }
3580
3581 list_add(&reloc_root->root_list, &reloc_roots);
3582
3583 if (btrfs_root_refs(&reloc_root->root_item) > 0) {
3584 fs_root = read_fs_root(root->fs_info,
3585 reloc_root->root_key.offset);
3586 if (IS_ERR(fs_root)) {
3587 err = PTR_ERR(fs_root);
3588 goto out;
3589 }
3590 }
3591
3592 if (key.offset == 0)
3593 break;
3594
3595 key.offset--;
3596 }
3597 btrfs_release_path(root->fs_info->tree_root, path);
3598
3599 if (list_empty(&reloc_roots))
3600 goto out;
3601
3602 rc = kzalloc(sizeof(*rc), GFP_NOFS);
3603 if (!rc) {
3604 err = -ENOMEM;
3605 goto out;
3606 }
3607
3608 mapping_tree_init(&rc->reloc_root_tree);
3609 INIT_LIST_HEAD(&rc->reloc_roots);
3610 btrfs_init_workers(&rc->workers, "relocate",
3611 root->fs_info->thread_pool_size);
3612 rc->extent_root = root->fs_info->extent_root;
3613
3614 set_reloc_control(rc);
3615
3616 while (!list_empty(&reloc_roots)) {
3617 reloc_root = list_entry(reloc_roots.next,
3618 struct btrfs_root, root_list);
3619 list_del(&reloc_root->root_list);
3620
3621 if (btrfs_root_refs(&reloc_root->root_item) == 0) {
3622 list_add_tail(&reloc_root->root_list,
3623 &rc->reloc_roots);
3624 continue;
3625 }
3626
3627 fs_root = read_fs_root(root->fs_info,
3628 reloc_root->root_key.offset);
3629 BUG_ON(IS_ERR(fs_root));
3630
3631 __add_reloc_root(reloc_root);
3632 fs_root->reloc_root = reloc_root;
3633 }
3634
3635 trans = btrfs_start_transaction(rc->extent_root, 1);
3636 btrfs_commit_transaction(trans, rc->extent_root);
3637
3638 merge_reloc_roots(rc);
3639
3640 unset_reloc_control(rc);
3641
3642 trans = btrfs_start_transaction(rc->extent_root, 1);
3643 btrfs_commit_transaction(trans, rc->extent_root);
3644 out:
3645 if (rc) {
3646 btrfs_stop_workers(&rc->workers);
3647 kfree(rc);
3648 }
3649 while (!list_empty(&reloc_roots)) {
3650 reloc_root = list_entry(reloc_roots.next,
3651 struct btrfs_root, root_list);
3652 list_del(&reloc_root->root_list);
3653 free_extent_buffer(reloc_root->node);
3654 free_extent_buffer(reloc_root->commit_root);
3655 kfree(reloc_root);
3656 }
3657 btrfs_free_path(path);
3658
3659 if (err == 0) {
3660 /* cleanup orphan inode in data relocation tree */
3661 fs_root = read_fs_root(root->fs_info,
3662 BTRFS_DATA_RELOC_TREE_OBJECTID);
3663 if (IS_ERR(fs_root))
3664 err = PTR_ERR(fs_root);
3665 }
3666 return err;
3667 }
3668
3669 /*
3670 * helper to add ordered checksum for data relocation.
3671 *
3672 * cloning checksum properly handles the nodatasum extents.
3673 * it also saves CPU time to re-calculate the checksum.
3674 */
3675 int btrfs_reloc_clone_csums(struct inode *inode, u64 file_pos, u64 len)
3676 {
3677 struct btrfs_ordered_sum *sums;
3678 struct btrfs_sector_sum *sector_sum;
3679 struct btrfs_ordered_extent *ordered;
3680 struct btrfs_root *root = BTRFS_I(inode)->root;
3681 size_t offset;
3682 int ret;
3683 u64 disk_bytenr;
3684 LIST_HEAD(list);
3685
3686 ordered = btrfs_lookup_ordered_extent(inode, file_pos);
3687 BUG_ON(ordered->file_offset != file_pos || ordered->len != len);
3688
3689 disk_bytenr = file_pos + BTRFS_I(inode)->index_cnt;
3690 ret = btrfs_lookup_csums_range(root->fs_info->csum_root, disk_bytenr,
3691 disk_bytenr + len - 1, &list);
3692
3693 while (!list_empty(&list)) {
3694 sums = list_entry(list.next, struct btrfs_ordered_sum, list);
3695 list_del_init(&sums->list);
3696
3697 sector_sum = sums->sums;
3698 sums->bytenr = ordered->start;
3699
3700 offset = 0;
3701 while (offset < sums->len) {
3702 sector_sum->bytenr += ordered->start - disk_bytenr;
3703 sector_sum++;
3704 offset += root->sectorsize;
3705 }
3706
3707 btrfs_add_ordered_sum(inode, ordered, sums);
3708 }
3709 btrfs_put_ordered_extent(ordered);
3710 return 0;
3711 }
Linux with added FPC-III support