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tty: Mark generic_serial users as BROKEN
[linux-2.6/verdex.git] / fs / btrfs / relocation.c
blobc04f7f212602c4bcb71e58db938fcd0d8a9128ad
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 if (ret > 0 && path2->slots[level] > 0)
674 path2->slots[level]--;
675
676 eb = path2->nodes[level];
677 WARN_ON(btrfs_node_blockptr(eb, path2->slots[level]) !=
678 cur->bytenr);
679
680 lower = cur;
681 for (; level < BTRFS_MAX_LEVEL; level++) {
682 if (!path2->nodes[level]) {
683 BUG_ON(btrfs_root_bytenr(&root->root_item) !=
684 lower->bytenr);
685 lower->root = root;
686 break;
687 }
688
689 edge = kzalloc(sizeof(*edge), GFP_NOFS);
690 if (!edge) {
691 err = -ENOMEM;
692 goto out;
693 }
694
695 eb = path2->nodes[level];
696 rb_node = tree_search(&cache->rb_root, eb->start);
697 if (!rb_node) {
698 upper = kmalloc(sizeof(*upper), GFP_NOFS);
699 if (!upper) {
700 kfree(edge);
701 err = -ENOMEM;
702 goto out;
703 }
704 backref_node_init(upper);
705 upper->bytenr = eb->start;
706 upper->owner = btrfs_header_owner(eb);
707 upper->level = lower->level + 1;
708
709 /*
710 * if we know the block isn't shared
711 * we can void checking its backrefs.
712 */
713 if (btrfs_block_can_be_shared(root, eb))
714 upper->checked = 0;
715 else
716 upper->checked = 1;
717
718 /*
719 * add the block to pending list if we
720 * need check its backrefs. only block
721 * at 'cur->level + 1' is added to the
722 * tail of pending list. this guarantees
723 * we check backrefs from lower level
724 * blocks to upper level blocks.
725 */
726 if (!upper->checked &&
727 level == cur->level + 1) {
728 list_add_tail(&edge->list[UPPER],
729 &list);
730 } else
731 INIT_LIST_HEAD(&edge->list[UPPER]);
732 } else {
733 upper = rb_entry(rb_node, struct backref_node,
734 rb_node);
735 BUG_ON(!upper->checked);
736 INIT_LIST_HEAD(&edge->list[UPPER]);
737 }
738 list_add_tail(&edge->list[LOWER], &lower->upper);
739 edge->node[UPPER] = upper;
740 edge->node[LOWER] = lower;
741
742 if (rb_node)
743 break;
744 lower = upper;
745 upper = NULL;
746 }
747 btrfs_release_path(root, path2);
748 next:
749 if (ptr < end) {
750 ptr += btrfs_extent_inline_ref_size(key.type);
751 if (ptr >= end) {
752 WARN_ON(ptr > end);
753 ptr = 0;
754 end = 0;
755 }
756 }
757 if (ptr >= end)
758 path1->slots[0]++;
759 }
760 btrfs_release_path(rc->extent_root, path1);
761
762 cur->checked = 1;
763 WARN_ON(exist);
764
765 /* the pending list isn't empty, take the first block to process */
766 if (!list_empty(&list)) {
767 edge = list_entry(list.next, struct backref_edge, list[UPPER]);
768 list_del_init(&edge->list[UPPER]);
769 cur = edge->node[UPPER];
770 goto again;
771 }
772
773 /*
774 * everything goes well, connect backref nodes and insert backref nodes
775 * into the cache.
776 */
777 BUG_ON(!node->checked);
778 rb_node = tree_insert(&cache->rb_root, node->bytenr, &node->rb_node);
779 BUG_ON(rb_node);
780
781 list_for_each_entry(edge, &node->upper, list[LOWER])
782 list_add_tail(&edge->list[UPPER], &list);
783
784 while (!list_empty(&list)) {
785 edge = list_entry(list.next, struct backref_edge, list[UPPER]);
786 list_del_init(&edge->list[UPPER]);
787 upper = edge->node[UPPER];
788
789 if (!RB_EMPTY_NODE(&upper->rb_node)) {
790 if (upper->lowest) {
791 list_del_init(&upper->lower);
792 upper->lowest = 0;
793 }
794
795 list_add_tail(&edge->list[UPPER], &upper->lower);
796 continue;
797 }
798
799 BUG_ON(!upper->checked);
800 rb_node = tree_insert(&cache->rb_root, upper->bytenr,
801 &upper->rb_node);
802 BUG_ON(rb_node);
803
804 list_add_tail(&edge->list[UPPER], &upper->lower);
805
806 list_for_each_entry(edge, &upper->upper, list[LOWER])
807 list_add_tail(&edge->list[UPPER], &list);
808 }
809 out:
810 btrfs_free_path(path1);
811 btrfs_free_path(path2);
812 if (err) {
813 INIT_LIST_HEAD(&list);
814 upper = node;
815 while (upper) {
816 if (RB_EMPTY_NODE(&upper->rb_node)) {
817 list_splice_tail(&upper->upper, &list);
818 kfree(upper);
819 }
820
821 if (list_empty(&list))
822 break;
823
824 edge = list_entry(list.next, struct backref_edge,
825 list[LOWER]);
826 upper = edge->node[UPPER];
827 kfree(edge);
828 }
829 return ERR_PTR(err);
830 }
831 return node;
832 }
833
834 /*
835 * helper to add 'address of tree root -> reloc tree' mapping
836 */
837 static int __add_reloc_root(struct btrfs_root *root)
838 {
839 struct rb_node *rb_node;
840 struct mapping_node *node;
841 struct reloc_control *rc = root->fs_info->reloc_ctl;
842
843 node = kmalloc(sizeof(*node), GFP_NOFS);
844 BUG_ON(!node);
845
846 node->bytenr = root->node->start;
847 node->data = root;
848
849 spin_lock(&rc->reloc_root_tree.lock);
850 rb_node = tree_insert(&rc->reloc_root_tree.rb_root,
851 node->bytenr, &node->rb_node);
852 spin_unlock(&rc->reloc_root_tree.lock);
853 BUG_ON(rb_node);
854
855 list_add_tail(&root->root_list, &rc->reloc_roots);
856 return 0;
857 }
858
859 /*
860 * helper to update/delete the 'address of tree root -> reloc tree'
861 * mapping
862 */
863 static int __update_reloc_root(struct btrfs_root *root, int del)
864 {
865 struct rb_node *rb_node;
866 struct mapping_node *node = NULL;
867 struct reloc_control *rc = root->fs_info->reloc_ctl;
868
869 spin_lock(&rc->reloc_root_tree.lock);
870 rb_node = tree_search(&rc->reloc_root_tree.rb_root,
871 root->commit_root->start);
872 if (rb_node) {
873 node = rb_entry(rb_node, struct mapping_node, rb_node);
874 rb_erase(&node->rb_node, &rc->reloc_root_tree.rb_root);
875 }
876 spin_unlock(&rc->reloc_root_tree.lock);
877
878 BUG_ON((struct btrfs_root *)node->data != root);
879
880 if (!del) {
881 spin_lock(&rc->reloc_root_tree.lock);
882 node->bytenr = root->node->start;
883 rb_node = tree_insert(&rc->reloc_root_tree.rb_root,
884 node->bytenr, &node->rb_node);
885 spin_unlock(&rc->reloc_root_tree.lock);
886 BUG_ON(rb_node);
887 } else {
888 list_del_init(&root->root_list);
889 kfree(node);
890 }
891 return 0;
892 }
893
894 /*
895 * create reloc tree for a given fs tree. reloc tree is just a
896 * snapshot of the fs tree with special root objectid.
897 */
898 int btrfs_init_reloc_root(struct btrfs_trans_handle *trans,
899 struct btrfs_root *root)
900 {
901 struct btrfs_root *reloc_root;
902 struct extent_buffer *eb;
903 struct btrfs_root_item *root_item;
904 struct btrfs_key root_key;
905 int ret;
906
907 if (root->reloc_root) {
908 reloc_root = root->reloc_root;
909 reloc_root->last_trans = trans->transid;
910 return 0;
911 }
912
913 if (!root->fs_info->reloc_ctl ||
914 !root->fs_info->reloc_ctl->create_reloc_root ||
915 root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID)
916 return 0;
917
918 root_item = kmalloc(sizeof(*root_item), GFP_NOFS);
919 BUG_ON(!root_item);
920
921 root_key.objectid = BTRFS_TREE_RELOC_OBJECTID;
922 root_key.type = BTRFS_ROOT_ITEM_KEY;
923 root_key.offset = root->root_key.objectid;
924
925 ret = btrfs_copy_root(trans, root, root->commit_root, &eb,
926 BTRFS_TREE_RELOC_OBJECTID);
927 BUG_ON(ret);
928
929 btrfs_set_root_last_snapshot(&root->root_item, trans->transid - 1);
930 memcpy(root_item, &root->root_item, sizeof(*root_item));
931 btrfs_set_root_refs(root_item, 1);
932 btrfs_set_root_bytenr(root_item, eb->start);
933 btrfs_set_root_level(root_item, btrfs_header_level(eb));
934 btrfs_set_root_generation(root_item, trans->transid);
935 memset(&root_item->drop_progress, 0, sizeof(struct btrfs_disk_key));
936 root_item->drop_level = 0;
937
938 btrfs_tree_unlock(eb);
939 free_extent_buffer(eb);
940
941 ret = btrfs_insert_root(trans, root->fs_info->tree_root,
942 &root_key, root_item);
943 BUG_ON(ret);
944 kfree(root_item);
945
946 reloc_root = btrfs_read_fs_root_no_radix(root->fs_info->tree_root,
947 &root_key);
948 BUG_ON(IS_ERR(reloc_root));
949 reloc_root->last_trans = trans->transid;
950
951 __add_reloc_root(reloc_root);
952 root->reloc_root = reloc_root;
953 return 0;
954 }
955
956 /*
957 * update root item of reloc tree
958 */
959 int btrfs_update_reloc_root(struct btrfs_trans_handle *trans,
960 struct btrfs_root *root)
961 {
962 struct btrfs_root *reloc_root;
963 struct btrfs_root_item *root_item;
964 int del = 0;
965 int ret;
966
967 if (!root->reloc_root)
968 return 0;
969
970 reloc_root = root->reloc_root;
971 root_item = &reloc_root->root_item;
972
973 if (btrfs_root_refs(root_item) == 0) {
974 root->reloc_root = NULL;
975 del = 1;
976 }
977
978 __update_reloc_root(reloc_root, del);
979
980 if (reloc_root->commit_root != reloc_root->node) {
981 btrfs_set_root_node(root_item, reloc_root->node);
982 free_extent_buffer(reloc_root->commit_root);
983 reloc_root->commit_root = btrfs_root_node(reloc_root);
984 }
985
986 ret = btrfs_update_root(trans, root->fs_info->tree_root,
987 &reloc_root->root_key, root_item);
988 BUG_ON(ret);
989 return 0;
990 }
991
992 /*
993 * helper to find first cached inode with inode number >= objectid
994 * in a subvolume
995 */
996 static struct inode *find_next_inode(struct btrfs_root *root, u64 objectid)
997 {
998 struct rb_node *node;
999 struct rb_node *prev;
1000 struct btrfs_inode *entry;
1001 struct inode *inode;
1002
1003 spin_lock(&root->inode_lock);
1004 again:
1005 node = root->inode_tree.rb_node;
1006 prev = NULL;
1007 while (node) {
1008 prev = node;
1009 entry = rb_entry(node, struct btrfs_inode, rb_node);
1010
1011 if (objectid < entry->vfs_inode.i_ino)
1012 node = node->rb_left;
1013 else if (objectid > entry->vfs_inode.i_ino)
1014 node = node->rb_right;
1015 else
1016 break;
1017 }
1018 if (!node) {
1019 while (prev) {
1020 entry = rb_entry(prev, struct btrfs_inode, rb_node);
1021 if (objectid <= entry->vfs_inode.i_ino) {
1022 node = prev;
1023 break;
1024 }
1025 prev = rb_next(prev);
1026 }
1027 }
1028 while (node) {
1029 entry = rb_entry(node, struct btrfs_inode, rb_node);
1030 inode = igrab(&entry->vfs_inode);
1031 if (inode) {
1032 spin_unlock(&root->inode_lock);
1033 return inode;
1034 }
1035
1036 objectid = entry->vfs_inode.i_ino + 1;
1037 if (cond_resched_lock(&root->inode_lock))
1038 goto again;
1039
1040 node = rb_next(node);
1041 }
1042 spin_unlock(&root->inode_lock);
1043 return NULL;
1044 }
1045
1046 static int in_block_group(u64 bytenr,
1047 struct btrfs_block_group_cache *block_group)
1048 {
1049 if (bytenr >= block_group->key.objectid &&
1050 bytenr < block_group->key.objectid + block_group->key.offset)
1051 return 1;
1052 return 0;
1053 }
1054
1055 /*
1056 * get new location of data
1057 */
1058 static int get_new_location(struct inode *reloc_inode, u64 *new_bytenr,
1059 u64 bytenr, u64 num_bytes)
1060 {
1061 struct btrfs_root *root = BTRFS_I(reloc_inode)->root;
1062 struct btrfs_path *path;
1063 struct btrfs_file_extent_item *fi;
1064 struct extent_buffer *leaf;
1065 int ret;
1066
1067 path = btrfs_alloc_path();
1068 if (!path)
1069 return -ENOMEM;
1070
1071 bytenr -= BTRFS_I(reloc_inode)->index_cnt;
1072 ret = btrfs_lookup_file_extent(NULL, root, path, reloc_inode->i_ino,
1073 bytenr, 0);
1074 if (ret < 0)
1075 goto out;
1076 if (ret > 0) {
1077 ret = -ENOENT;
1078 goto out;
1079 }
1080
1081 leaf = path->nodes[0];
1082 fi = btrfs_item_ptr(leaf, path->slots[0],
1083 struct btrfs_file_extent_item);
1084
1085 BUG_ON(btrfs_file_extent_offset(leaf, fi) ||
1086 btrfs_file_extent_compression(leaf, fi) ||
1087 btrfs_file_extent_encryption(leaf, fi) ||
1088 btrfs_file_extent_other_encoding(leaf, fi));
1089
1090 if (num_bytes != btrfs_file_extent_disk_num_bytes(leaf, fi)) {
1091 ret = 1;
1092 goto out;
1093 }
1094
1095 if (new_bytenr)
1096 *new_bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
1097 ret = 0;
1098 out:
1099 btrfs_free_path(path);
1100 return ret;
1101 }
1102
1103 /*
1104 * update file extent items in the tree leaf to point to
1105 * the new locations.
1106 */
1107 static int replace_file_extents(struct btrfs_trans_handle *trans,
1108 struct reloc_control *rc,
1109 struct btrfs_root *root,
1110 struct extent_buffer *leaf,
1111 struct list_head *inode_list)
1112 {
1113 struct btrfs_key key;
1114 struct btrfs_file_extent_item *fi;
1115 struct inode *inode = NULL;
1116 struct inodevec *ivec = NULL;
1117 u64 parent;
1118 u64 bytenr;
1119 u64 new_bytenr;
1120 u64 num_bytes;
1121 u64 end;
1122 u32 nritems;
1123 u32 i;
1124 int ret;
1125 int first = 1;
1126 int dirty = 0;
1127
1128 if (rc->stage != UPDATE_DATA_PTRS)
1129 return 0;
1130
1131 /* reloc trees always use full backref */
1132 if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID)
1133 parent = leaf->start;
1134 else
1135 parent = 0;
1136
1137 nritems = btrfs_header_nritems(leaf);
1138 for (i = 0; i < nritems; i++) {
1139 cond_resched();
1140 btrfs_item_key_to_cpu(leaf, &key, i);
1141 if (key.type != BTRFS_EXTENT_DATA_KEY)
1142 continue;
1143 fi = btrfs_item_ptr(leaf, i, struct btrfs_file_extent_item);
1144 if (btrfs_file_extent_type(leaf, fi) ==
1145 BTRFS_FILE_EXTENT_INLINE)
1146 continue;
1147 bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
1148 num_bytes = btrfs_file_extent_disk_num_bytes(leaf, fi);
1149 if (bytenr == 0)
1150 continue;
1151 if (!in_block_group(bytenr, rc->block_group))
1152 continue;
1153
1154 /*
1155 * if we are modifying block in fs tree, wait for readpage
1156 * to complete and drop the extent cache
1157 */
1158 if (root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID) {
1159 if (!ivec || ivec->nr == INODEVEC_SIZE) {
1160 ivec = kmalloc(sizeof(*ivec), GFP_NOFS);
1161 BUG_ON(!ivec);
1162 ivec->nr = 0;
1163 list_add_tail(&ivec->list, inode_list);
1164 }
1165 if (first) {
1166 inode = find_next_inode(root, key.objectid);
1167 if (inode)
1168 ivec->inode[ivec->nr++] = inode;
1169 first = 0;
1170 } else if (inode && inode->i_ino < key.objectid) {
1171 inode = find_next_inode(root, key.objectid);
1172 if (inode)
1173 ivec->inode[ivec->nr++] = inode;
1174 }
1175 if (inode && inode->i_ino == key.objectid) {
1176 end = key.offset +
1177 btrfs_file_extent_num_bytes(leaf, fi);
1178 WARN_ON(!IS_ALIGNED(key.offset,
1179 root->sectorsize));
1180 WARN_ON(!IS_ALIGNED(end, root->sectorsize));
1181 end--;
1182 ret = try_lock_extent(&BTRFS_I(inode)->io_tree,
1183 key.offset, end,
1184 GFP_NOFS);
1185 if (!ret)
1186 continue;
1187
1188 btrfs_drop_extent_cache(inode, key.offset, end,
1189 1);
1190 unlock_extent(&BTRFS_I(inode)->io_tree,
1191 key.offset, end, GFP_NOFS);
1192 }
1193 }
1194
1195 ret = get_new_location(rc->data_inode, &new_bytenr,
1196 bytenr, num_bytes);
1197 if (ret > 0)
1198 continue;
1199 BUG_ON(ret < 0);
1200
1201 btrfs_set_file_extent_disk_bytenr(leaf, fi, new_bytenr);
1202 dirty = 1;
1203
1204 key.offset -= btrfs_file_extent_offset(leaf, fi);
1205 ret = btrfs_inc_extent_ref(trans, root, new_bytenr,
1206 num_bytes, parent,
1207 btrfs_header_owner(leaf),
1208 key.objectid, key.offset);
1209 BUG_ON(ret);
1210
1211 ret = btrfs_free_extent(trans, root, bytenr, num_bytes,
1212 parent, btrfs_header_owner(leaf),
1213 key.objectid, key.offset);
1214 BUG_ON(ret);
1215 }
1216 if (dirty)
1217 btrfs_mark_buffer_dirty(leaf);
1218 return 0;
1219 }
1220
1221 static noinline_for_stack
1222 int memcmp_node_keys(struct extent_buffer *eb, int slot,
1223 struct btrfs_path *path, int level)
1224 {
1225 struct btrfs_disk_key key1;
1226 struct btrfs_disk_key key2;
1227 btrfs_node_key(eb, &key1, slot);
1228 btrfs_node_key(path->nodes[level], &key2, path->slots[level]);
1229 return memcmp(&key1, &key2, sizeof(key1));
1230 }
1231
1232 /*
1233 * try to replace tree blocks in fs tree with the new blocks
1234 * in reloc tree. tree blocks haven't been modified since the
1235 * reloc tree was create can be replaced.
1236 *
1237 * if a block was replaced, level of the block + 1 is returned.
1238 * if no block got replaced, 0 is returned. if there are other
1239 * errors, a negative error number is returned.
1240 */
1241 static int replace_path(struct btrfs_trans_handle *trans,
1242 struct btrfs_root *dest, struct btrfs_root *src,
1243 struct btrfs_path *path, struct btrfs_key *next_key,
1244 struct extent_buffer **leaf,
1245 int lowest_level, int max_level)
1246 {
1247 struct extent_buffer *eb;
1248 struct extent_buffer *parent;
1249 struct btrfs_key key;
1250 u64 old_bytenr;
1251 u64 new_bytenr;
1252 u64 old_ptr_gen;
1253 u64 new_ptr_gen;
1254 u64 last_snapshot;
1255 u32 blocksize;
1256 int level;
1257 int ret;
1258 int slot;
1259
1260 BUG_ON(src->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID);
1261 BUG_ON(dest->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID);
1262 BUG_ON(lowest_level > 1 && leaf);
1263
1264 last_snapshot = btrfs_root_last_snapshot(&src->root_item);
1265
1266 slot = path->slots[lowest_level];
1267 btrfs_node_key_to_cpu(path->nodes[lowest_level], &key, slot);
1268
1269 eb = btrfs_lock_root_node(dest);
1270 btrfs_set_lock_blocking(eb);
1271 level = btrfs_header_level(eb);
1272
1273 if (level < lowest_level) {
1274 btrfs_tree_unlock(eb);
1275 free_extent_buffer(eb);
1276 return 0;
1277 }
1278
1279 ret = btrfs_cow_block(trans, dest, eb, NULL, 0, &eb);
1280 BUG_ON(ret);
1281 btrfs_set_lock_blocking(eb);
1282
1283 if (next_key) {
1284 next_key->objectid = (u64)-1;
1285 next_key->type = (u8)-1;
1286 next_key->offset = (u64)-1;
1287 }
1288
1289 parent = eb;
1290 while (1) {
1291 level = btrfs_header_level(parent);
1292 BUG_ON(level < lowest_level);
1293
1294 ret = btrfs_bin_search(parent, &key, level, &slot);
1295 if (ret && slot > 0)
1296 slot--;
1297
1298 if (next_key && slot + 1 < btrfs_header_nritems(parent))
1299 btrfs_node_key_to_cpu(parent, next_key, slot + 1);
1300
1301 old_bytenr = btrfs_node_blockptr(parent, slot);
1302 blocksize = btrfs_level_size(dest, level - 1);
1303 old_ptr_gen = btrfs_node_ptr_generation(parent, slot);
1304
1305 if (level <= max_level) {
1306 eb = path->nodes[level];
1307 new_bytenr = btrfs_node_blockptr(eb,
1308 path->slots[level]);
1309 new_ptr_gen = btrfs_node_ptr_generation(eb,
1310 path->slots[level]);
1311 } else {
1312 new_bytenr = 0;
1313 new_ptr_gen = 0;
1314 }
1315
1316 if (new_bytenr > 0 && new_bytenr == old_bytenr) {
1317 WARN_ON(1);
1318 ret = level;
1319 break;
1320 }
1321
1322 if (new_bytenr == 0 || old_ptr_gen > last_snapshot ||
1323 memcmp_node_keys(parent, slot, path, level)) {
1324 if (level <= lowest_level && !leaf) {
1325 ret = 0;
1326 break;
1327 }
1328
1329 eb = read_tree_block(dest, old_bytenr, blocksize,
1330 old_ptr_gen);
1331 btrfs_tree_lock(eb);
1332 ret = btrfs_cow_block(trans, dest, eb, parent,
1333 slot, &eb);
1334 BUG_ON(ret);
1335 btrfs_set_lock_blocking(eb);
1336
1337 if (level <= lowest_level) {
1338 *leaf = eb;
1339 ret = 0;
1340 break;
1341 }
1342
1343 btrfs_tree_unlock(parent);
1344 free_extent_buffer(parent);
1345
1346 parent = eb;
1347 continue;
1348 }
1349
1350 btrfs_node_key_to_cpu(path->nodes[level], &key,
1351 path->slots[level]);
1352 btrfs_release_path(src, path);
1353
1354 path->lowest_level = level;
1355 ret = btrfs_search_slot(trans, src, &key, path, 0, 1);
1356 path->lowest_level = 0;
1357 BUG_ON(ret);
1358
1359 /*
1360 * swap blocks in fs tree and reloc tree.
1361 */
1362 btrfs_set_node_blockptr(parent, slot, new_bytenr);
1363 btrfs_set_node_ptr_generation(parent, slot, new_ptr_gen);
1364 btrfs_mark_buffer_dirty(parent);
1365
1366 btrfs_set_node_blockptr(path->nodes[level],
1367 path->slots[level], old_bytenr);
1368 btrfs_set_node_ptr_generation(path->nodes[level],
1369 path->slots[level], old_ptr_gen);
1370 btrfs_mark_buffer_dirty(path->nodes[level]);
1371
1372 ret = btrfs_inc_extent_ref(trans, src, old_bytenr, blocksize,
1373 path->nodes[level]->start,
1374 src->root_key.objectid, level - 1, 0);
1375 BUG_ON(ret);
1376 ret = btrfs_inc_extent_ref(trans, dest, new_bytenr, blocksize,
1377 0, dest->root_key.objectid, level - 1,
1378 0);
1379 BUG_ON(ret);
1380
1381 ret = btrfs_free_extent(trans, src, new_bytenr, blocksize,
1382 path->nodes[level]->start,
1383 src->root_key.objectid, level - 1, 0);
1384 BUG_ON(ret);
1385
1386 ret = btrfs_free_extent(trans, dest, old_bytenr, blocksize,
1387 0, dest->root_key.objectid, level - 1,
1388 0);
1389 BUG_ON(ret);
1390
1391 btrfs_unlock_up_safe(path, 0);
1392
1393 ret = level;
1394 break;
1395 }
1396 btrfs_tree_unlock(parent);
1397 free_extent_buffer(parent);
1398 return ret;
1399 }
1400
1401 /*
1402 * helper to find next relocated block in reloc tree
1403 */
1404 static noinline_for_stack
1405 int walk_up_reloc_tree(struct btrfs_root *root, struct btrfs_path *path,
1406 int *level)
1407 {
1408 struct extent_buffer *eb;
1409 int i;
1410 u64 last_snapshot;
1411 u32 nritems;
1412
1413 last_snapshot = btrfs_root_last_snapshot(&root->root_item);
1414
1415 for (i = 0; i < *level; i++) {
1416 free_extent_buffer(path->nodes[i]);
1417 path->nodes[i] = NULL;
1418 }
1419
1420 for (i = *level; i < BTRFS_MAX_LEVEL && path->nodes[i]; i++) {
1421 eb = path->nodes[i];
1422 nritems = btrfs_header_nritems(eb);
1423 while (path->slots[i] + 1 < nritems) {
1424 path->slots[i]++;
1425 if (btrfs_node_ptr_generation(eb, path->slots[i]) <=
1426 last_snapshot)
1427 continue;
1428
1429 *level = i;
1430 return 0;
1431 }
1432 free_extent_buffer(path->nodes[i]);
1433 path->nodes[i] = NULL;
1434 }
1435 return 1;
1436 }
1437
1438 /*
1439 * walk down reloc tree to find relocated block of lowest level
1440 */
1441 static noinline_for_stack
1442 int walk_down_reloc_tree(struct btrfs_root *root, struct btrfs_path *path,
1443 int *level)
1444 {
1445 struct extent_buffer *eb = NULL;
1446 int i;
1447 u64 bytenr;
1448 u64 ptr_gen = 0;
1449 u64 last_snapshot;
1450 u32 blocksize;
1451 u32 nritems;
1452
1453 last_snapshot = btrfs_root_last_snapshot(&root->root_item);
1454
1455 for (i = *level; i > 0; i--) {
1456 eb = path->nodes[i];
1457 nritems = btrfs_header_nritems(eb);
1458 while (path->slots[i] < nritems) {
1459 ptr_gen = btrfs_node_ptr_generation(eb, path->slots[i]);
1460 if (ptr_gen > last_snapshot)
1461 break;
1462 path->slots[i]++;
1463 }
1464 if (path->slots[i] >= nritems) {
1465 if (i == *level)
1466 break;
1467 *level = i + 1;
1468 return 0;
1469 }
1470 if (i == 1) {
1471 *level = i;
1472 return 0;
1473 }
1474
1475 bytenr = btrfs_node_blockptr(eb, path->slots[i]);
1476 blocksize = btrfs_level_size(root, i - 1);
1477 eb = read_tree_block(root, bytenr, blocksize, ptr_gen);
1478 BUG_ON(btrfs_header_level(eb) != i - 1);
1479 path->nodes[i - 1] = eb;
1480 path->slots[i - 1] = 0;
1481 }
1482 return 1;
1483 }
1484
1485 /*
1486 * invalidate extent cache for file extents whose key in range of
1487 * [min_key, max_key)
1488 */
1489 static int invalidate_extent_cache(struct btrfs_root *root,
1490 struct btrfs_key *min_key,
1491 struct btrfs_key *max_key)
1492 {
1493 struct inode *inode = NULL;
1494 u64 objectid;
1495 u64 start, end;
1496
1497 objectid = min_key->objectid;
1498 while (1) {
1499 cond_resched();
1500 iput(inode);
1501
1502 if (objectid > max_key->objectid)
1503 break;
1504
1505 inode = find_next_inode(root, objectid);
1506 if (!inode)
1507 break;
1508
1509 if (inode->i_ino > max_key->objectid) {
1510 iput(inode);
1511 break;
1512 }
1513
1514 objectid = inode->i_ino + 1;
1515 if (!S_ISREG(inode->i_mode))
1516 continue;
1517
1518 if (unlikely(min_key->objectid == inode->i_ino)) {
1519 if (min_key->type > BTRFS_EXTENT_DATA_KEY)
1520 continue;
1521 if (min_key->type < BTRFS_EXTENT_DATA_KEY)
1522 start = 0;
1523 else {
1524 start = min_key->offset;
1525 WARN_ON(!IS_ALIGNED(start, root->sectorsize));
1526 }
1527 } else {
1528 start = 0;
1529 }
1530
1531 if (unlikely(max_key->objectid == inode->i_ino)) {
1532 if (max_key->type < BTRFS_EXTENT_DATA_KEY)
1533 continue;
1534 if (max_key->type > BTRFS_EXTENT_DATA_KEY) {
1535 end = (u64)-1;
1536 } else {
1537 if (max_key->offset == 0)
1538 continue;
1539 end = max_key->offset;
1540 WARN_ON(!IS_ALIGNED(end, root->sectorsize));
1541 end--;
1542 }
1543 } else {
1544 end = (u64)-1;
1545 }
1546
1547 /* the lock_extent waits for readpage to complete */
1548 lock_extent(&BTRFS_I(inode)->io_tree, start, end, GFP_NOFS);
1549 btrfs_drop_extent_cache(inode, start, end, 1);
1550 unlock_extent(&BTRFS_I(inode)->io_tree, start, end, GFP_NOFS);
1551 }
1552 return 0;
1553 }
1554
1555 static int find_next_key(struct btrfs_path *path, int level,
1556 struct btrfs_key *key)
1557
1558 {
1559 while (level < BTRFS_MAX_LEVEL) {
1560 if (!path->nodes[level])
1561 break;
1562 if (path->slots[level] + 1 <
1563 btrfs_header_nritems(path->nodes[level])) {
1564 btrfs_node_key_to_cpu(path->nodes[level], key,
1565 path->slots[level] + 1);
1566 return 0;
1567 }
1568 level++;
1569 }
1570 return 1;
1571 }
1572
1573 /*
1574 * merge the relocated tree blocks in reloc tree with corresponding
1575 * fs tree.
1576 */
1577 static noinline_for_stack int merge_reloc_root(struct reloc_control *rc,
1578 struct btrfs_root *root)
1579 {
1580 LIST_HEAD(inode_list);
1581 struct btrfs_key key;
1582 struct btrfs_key next_key;
1583 struct btrfs_trans_handle *trans;
1584 struct btrfs_root *reloc_root;
1585 struct btrfs_root_item *root_item;
1586 struct btrfs_path *path;
1587 struct extent_buffer *leaf = NULL;
1588 unsigned long nr;
1589 int level;
1590 int max_level;
1591 int replaced = 0;
1592 int ret;
1593 int err = 0;
1594
1595 path = btrfs_alloc_path();
1596 if (!path)
1597 return -ENOMEM;
1598
1599 reloc_root = root->reloc_root;
1600 root_item = &reloc_root->root_item;
1601
1602 if (btrfs_disk_key_objectid(&root_item->drop_progress) == 0) {
1603 level = btrfs_root_level(root_item);
1604 extent_buffer_get(reloc_root->node);
1605 path->nodes[level] = reloc_root->node;
1606 path->slots[level] = 0;
1607 } else {
1608 btrfs_disk_key_to_cpu(&key, &root_item->drop_progress);
1609
1610 level = root_item->drop_level;
1611 BUG_ON(level == 0);
1612 path->lowest_level = level;
1613 ret = btrfs_search_slot(NULL, reloc_root, &key, path, 0, 0);
1614 path->lowest_level = 0;
1615 if (ret < 0) {
1616 btrfs_free_path(path);
1617 return ret;
1618 }
1619
1620 btrfs_node_key_to_cpu(path->nodes[level], &next_key,
1621 path->slots[level]);
1622 WARN_ON(memcmp(&key, &next_key, sizeof(key)));
1623
1624 btrfs_unlock_up_safe(path, 0);
1625 }
1626
1627 if (level == 0 && rc->stage == UPDATE_DATA_PTRS) {
1628 trans = btrfs_start_transaction(root, 1);
1629
1630 leaf = path->nodes[0];
1631 btrfs_item_key_to_cpu(leaf, &key, 0);
1632 btrfs_release_path(reloc_root, path);
1633
1634 ret = btrfs_search_slot(trans, root, &key, path, 0, 1);
1635 if (ret < 0) {
1636 err = ret;
1637 goto out;
1638 }
1639
1640 leaf = path->nodes[0];
1641 btrfs_unlock_up_safe(path, 1);
1642 ret = replace_file_extents(trans, rc, root, leaf,
1643 &inode_list);
1644 if (ret < 0)
1645 err = ret;
1646 goto out;
1647 }
1648
1649 memset(&next_key, 0, sizeof(next_key));
1650
1651 while (1) {
1652 leaf = NULL;
1653 replaced = 0;
1654 trans = btrfs_start_transaction(root, 1);
1655 max_level = level;
1656
1657 ret = walk_down_reloc_tree(reloc_root, path, &level);
1658 if (ret < 0) {
1659 err = ret;
1660 goto out;
1661 }
1662 if (ret > 0)
1663 break;
1664
1665 if (!find_next_key(path, level, &key) &&
1666 btrfs_comp_cpu_keys(&next_key, &key) >= 0) {
1667 ret = 0;
1668 } else if (level == 1 && rc->stage == UPDATE_DATA_PTRS) {
1669 ret = replace_path(trans, root, reloc_root,
1670 path, &next_key, &leaf,
1671 level, max_level);
1672 } else {
1673 ret = replace_path(trans, root, reloc_root,
1674 path, &next_key, NULL,
1675 level, max_level);
1676 }
1677 if (ret < 0) {
1678 err = ret;
1679 goto out;
1680 }
1681
1682 if (ret > 0) {
1683 level = ret;
1684 btrfs_node_key_to_cpu(path->nodes[level], &key,
1685 path->slots[level]);
1686 replaced = 1;
1687 } else if (leaf) {
1688 /*
1689 * no block got replaced, try replacing file extents
1690 */
1691 btrfs_item_key_to_cpu(leaf, &key, 0);
1692 ret = replace_file_extents(trans, rc, root, leaf,
1693 &inode_list);
1694 btrfs_tree_unlock(leaf);
1695 free_extent_buffer(leaf);
1696 BUG_ON(ret < 0);
1697 }
1698
1699 ret = walk_up_reloc_tree(reloc_root, path, &level);
1700 if (ret > 0)
1701 break;
1702
1703 BUG_ON(level == 0);
1704 /*
1705 * save the merging progress in the drop_progress.
1706 * this is OK since root refs == 1 in this case.
1707 */
1708 btrfs_node_key(path->nodes[level], &root_item->drop_progress,
1709 path->slots[level]);
1710 root_item->drop_level = level;
1711
1712 nr = trans->blocks_used;
1713 btrfs_end_transaction(trans, root);
1714
1715 btrfs_btree_balance_dirty(root, nr);
1716
1717 if (replaced && rc->stage == UPDATE_DATA_PTRS)
1718 invalidate_extent_cache(root, &key, &next_key);
1719 }
1720
1721 /*
1722 * handle the case only one block in the fs tree need to be
1723 * relocated and the block is tree root.
1724 */
1725 leaf = btrfs_lock_root_node(root);
1726 ret = btrfs_cow_block(trans, root, leaf, NULL, 0, &leaf);
1727 btrfs_tree_unlock(leaf);
1728 free_extent_buffer(leaf);
1729 if (ret < 0)
1730 err = ret;
1731 out:
1732 btrfs_free_path(path);
1733
1734 if (err == 0) {
1735 memset(&root_item->drop_progress, 0,
1736 sizeof(root_item->drop_progress));
1737 root_item->drop_level = 0;
1738 btrfs_set_root_refs(root_item, 0);
1739 }
1740
1741 nr = trans->blocks_used;
1742 btrfs_end_transaction(trans, root);
1743
1744 btrfs_btree_balance_dirty(root, nr);
1745
1746 /*
1747 * put inodes while we aren't holding the tree locks
1748 */
1749 while (!list_empty(&inode_list)) {
1750 struct inodevec *ivec;
1751 ivec = list_entry(inode_list.next, struct inodevec, list);
1752 list_del(&ivec->list);
1753 while (ivec->nr > 0) {
1754 ivec->nr--;
1755 iput(ivec->inode[ivec->nr]);
1756 }
1757 kfree(ivec);
1758 }
1759
1760 if (replaced && rc->stage == UPDATE_DATA_PTRS)
1761 invalidate_extent_cache(root, &key, &next_key);
1762
1763 return err;
1764 }
1765
1766 /*
1767 * callback for the work threads.
1768 * this function merges reloc tree with corresponding fs tree,
1769 * and then drops the reloc tree.
1770 */
1771 static void merge_func(struct btrfs_work *work)
1772 {
1773 struct btrfs_trans_handle *trans;
1774 struct btrfs_root *root;
1775 struct btrfs_root *reloc_root;
1776 struct async_merge *async;
1777
1778 async = container_of(work, struct async_merge, work);
1779 reloc_root = async->root;
1780
1781 if (btrfs_root_refs(&reloc_root->root_item) > 0) {
1782 root = read_fs_root(reloc_root->fs_info,
1783 reloc_root->root_key.offset);
1784 BUG_ON(IS_ERR(root));
1785 BUG_ON(root->reloc_root != reloc_root);
1786
1787 merge_reloc_root(async->rc, root);
1788
1789 trans = btrfs_start_transaction(root, 1);
1790 btrfs_update_reloc_root(trans, root);
1791 btrfs_end_transaction(trans, root);
1792 }
1793
1794 btrfs_drop_snapshot(reloc_root, 0);
1795
1796 if (atomic_dec_and_test(async->num_pending))
1797 complete(async->done);
1798
1799 kfree(async);
1800 }
1801
1802 static int merge_reloc_roots(struct reloc_control *rc)
1803 {
1804 struct async_merge *async;
1805 struct btrfs_root *root;
1806 struct completion done;
1807 atomic_t num_pending;
1808
1809 init_completion(&done);
1810 atomic_set(&num_pending, 1);
1811
1812 while (!list_empty(&rc->reloc_roots)) {
1813 root = list_entry(rc->reloc_roots.next,
1814 struct btrfs_root, root_list);
1815 list_del_init(&root->root_list);
1816
1817 async = kmalloc(sizeof(*async), GFP_NOFS);
1818 BUG_ON(!async);
1819 async->work.func = merge_func;
1820 async->work.flags = 0;
1821 async->rc = rc;
1822 async->root = root;
1823 async->done = &done;
1824 async->num_pending = &num_pending;
1825 atomic_inc(&num_pending);
1826 btrfs_queue_worker(&rc->workers, &async->work);
1827 }
1828
1829 if (!atomic_dec_and_test(&num_pending))
1830 wait_for_completion(&done);
1831
1832 BUG_ON(!RB_EMPTY_ROOT(&rc->reloc_root_tree.rb_root));
1833 return 0;
1834 }
1835
1836 static void free_block_list(struct rb_root *blocks)
1837 {
1838 struct tree_block *block;
1839 struct rb_node *rb_node;
1840 while ((rb_node = rb_first(blocks))) {
1841 block = rb_entry(rb_node, struct tree_block, rb_node);
1842 rb_erase(rb_node, blocks);
1843 kfree(block);
1844 }
1845 }
1846
1847 static int record_reloc_root_in_trans(struct btrfs_trans_handle *trans,
1848 struct btrfs_root *reloc_root)
1849 {
1850 struct btrfs_root *root;
1851
1852 if (reloc_root->last_trans == trans->transid)
1853 return 0;
1854
1855 root = read_fs_root(reloc_root->fs_info, reloc_root->root_key.offset);
1856 BUG_ON(IS_ERR(root));
1857 BUG_ON(root->reloc_root != reloc_root);
1858
1859 return btrfs_record_root_in_trans(trans, root);
1860 }
1861
1862 /*
1863 * select one tree from trees that references the block.
1864 * for blocks in refernce counted trees, we preper reloc tree.
1865 * if no reloc tree found and reloc_only is true, NULL is returned.
1866 */
1867 static struct btrfs_root *__select_one_root(struct btrfs_trans_handle *trans,
1868 struct backref_node *node,
1869 struct backref_edge *edges[],
1870 int *nr, int reloc_only)
1871 {
1872 struct backref_node *next;
1873 struct btrfs_root *root;
1874 int index;
1875 int loop = 0;
1876 again:
1877 index = 0;
1878 next = node;
1879 while (1) {
1880 cond_resched();
1881 next = walk_up_backref(next, edges, &index);
1882 root = next->root;
1883 if (!root) {
1884 BUG_ON(!node->old_root);
1885 goto skip;
1886 }
1887
1888 /* no other choice for non-refernce counted tree */
1889 if (!root->ref_cows) {
1890 BUG_ON(reloc_only);
1891 break;
1892 }
1893
1894 if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID) {
1895 record_reloc_root_in_trans(trans, root);
1896 break;
1897 }
1898
1899 if (loop) {
1900 btrfs_record_root_in_trans(trans, root);
1901 break;
1902 }
1903
1904 if (reloc_only || next != node) {
1905 if (!root->reloc_root)
1906 btrfs_record_root_in_trans(trans, root);
1907 root = root->reloc_root;
1908 /*
1909 * if the reloc tree was created in current
1910 * transation, there is no node in backref tree
1911 * corresponds to the root of the reloc tree.
1912 */
1913 if (btrfs_root_last_snapshot(&root->root_item) ==
1914 trans->transid - 1)
1915 break;
1916 }
1917 skip:
1918 root = NULL;
1919 next = walk_down_backref(edges, &index);
1920 if (!next || next->level <= node->level)
1921 break;
1922 }
1923
1924 if (!root && !loop && !reloc_only) {
1925 loop = 1;
1926 goto again;
1927 }
1928
1929 if (root)
1930 *nr = index;
1931 else
1932 *nr = 0;
1933
1934 return root;
1935 }
1936
1937 static noinline_for_stack
1938 struct btrfs_root *select_one_root(struct btrfs_trans_handle *trans,
1939 struct backref_node *node)
1940 {
1941 struct backref_edge *edges[BTRFS_MAX_LEVEL - 1];
1942 int nr;
1943 return __select_one_root(trans, node, edges, &nr, 0);
1944 }
1945
1946 static noinline_for_stack
1947 struct btrfs_root *select_reloc_root(struct btrfs_trans_handle *trans,
1948 struct backref_node *node,
1949 struct backref_edge *edges[], int *nr)
1950 {
1951 return __select_one_root(trans, node, edges, nr, 1);
1952 }
1953
1954 static void grab_path_buffers(struct btrfs_path *path,
1955 struct backref_node *node,
1956 struct backref_edge *edges[], int nr)
1957 {
1958 int i = 0;
1959 while (1) {
1960 drop_node_buffer(node);
1961 node->eb = path->nodes[node->level];
1962 BUG_ON(!node->eb);
1963 if (path->locks[node->level])
1964 node->locked = 1;
1965 path->nodes[node->level] = NULL;
1966 path->locks[node->level] = 0;
1967
1968 if (i >= nr)
1969 break;
1970
1971 edges[i]->blockptr = node->eb->start;
1972 node = edges[i]->node[UPPER];
1973 i++;
1974 }
1975 }
1976
1977 /*
1978 * relocate a block tree, and then update pointers in upper level
1979 * blocks that reference the block to point to the new location.
1980 *
1981 * if called by link_to_upper, the block has already been relocated.
1982 * in that case this function just updates pointers.
1983 */
1984 static int do_relocation(struct btrfs_trans_handle *trans,
1985 struct backref_node *node,
1986 struct btrfs_key *key,
1987 struct btrfs_path *path, int lowest)
1988 {
1989 struct backref_node *upper;
1990 struct backref_edge *edge;
1991 struct backref_edge *edges[BTRFS_MAX_LEVEL - 1];
1992 struct btrfs_root *root;
1993 struct extent_buffer *eb;
1994 u32 blocksize;
1995 u64 bytenr;
1996 u64 generation;
1997 int nr;
1998 int slot;
1999 int ret;
2000 int err = 0;
2001
2002 BUG_ON(lowest && node->eb);
2003
2004 path->lowest_level = node->level + 1;
2005 list_for_each_entry(edge, &node->upper, list[LOWER]) {
2006 cond_resched();
2007 if (node->eb && node->eb->start == edge->blockptr)
2008 continue;
2009
2010 upper = edge->node[UPPER];
2011 root = select_reloc_root(trans, upper, edges, &nr);
2012 if (!root)
2013 continue;
2014
2015 if (upper->eb && !upper->locked)
2016 drop_node_buffer(upper);
2017
2018 if (!upper->eb) {
2019 ret = btrfs_search_slot(trans, root, key, path, 0, 1);
2020 if (ret < 0) {
2021 err = ret;
2022 break;
2023 }
2024 BUG_ON(ret > 0);
2025
2026 slot = path->slots[upper->level];
2027
2028 btrfs_unlock_up_safe(path, upper->level + 1);
2029 grab_path_buffers(path, upper, edges, nr);
2030
2031 btrfs_release_path(NULL, path);
2032 } else {
2033 ret = btrfs_bin_search(upper->eb, key, upper->level,
2034 &slot);
2035 BUG_ON(ret);
2036 }
2037
2038 bytenr = btrfs_node_blockptr(upper->eb, slot);
2039 if (!lowest) {
2040 if (node->eb->start == bytenr) {
2041 btrfs_tree_unlock(upper->eb);
2042 upper->locked = 0;
2043 continue;
2044 }
2045 } else {
2046 BUG_ON(node->bytenr != bytenr);
2047 }
2048
2049 blocksize = btrfs_level_size(root, node->level);
2050 generation = btrfs_node_ptr_generation(upper->eb, slot);
2051 eb = read_tree_block(root, bytenr, blocksize, generation);
2052 btrfs_tree_lock(eb);
2053 btrfs_set_lock_blocking(eb);
2054
2055 if (!node->eb) {
2056 ret = btrfs_cow_block(trans, root, eb, upper->eb,
2057 slot, &eb);
2058 if (ret < 0) {
2059 err = ret;
2060 break;
2061 }
2062 btrfs_set_lock_blocking(eb);
2063 node->eb = eb;
2064 node->locked = 1;
2065 } else {
2066 btrfs_set_node_blockptr(upper->eb, slot,
2067 node->eb->start);
2068 btrfs_set_node_ptr_generation(upper->eb, slot,
2069 trans->transid);
2070 btrfs_mark_buffer_dirty(upper->eb);
2071
2072 ret = btrfs_inc_extent_ref(trans, root,
2073 node->eb->start, blocksize,
2074 upper->eb->start,
2075 btrfs_header_owner(upper->eb),
2076 node->level, 0);
2077 BUG_ON(ret);
2078
2079 ret = btrfs_drop_subtree(trans, root, eb, upper->eb);
2080 BUG_ON(ret);
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 while (1) {
2557 ret = invalidate_inode_pages2_range(inode->i_mapping,
2558 first_index, last_index);
2559 if (ret != -EBUSY)
2560 break;
2561 schedule_timeout(HZ/10);
2562 }
2563 if (ret)
2564 goto out_unlock;
2565
2566 file_ra_state_init(ra, inode->i_mapping);
2567
2568 for (i = first_index ; i <= last_index; i++) {
2569 if (total_read % ra->ra_pages == 0) {
2570 btrfs_force_ra(inode->i_mapping, ra, NULL, i,
2571 min(last_index, ra->ra_pages + i - 1));
2572 }
2573 total_read++;
2574 again:
2575 if (((u64)i << PAGE_CACHE_SHIFT) > i_size_read(inode))
2576 BUG_ON(1);
2577 page = grab_cache_page(inode->i_mapping, i);
2578 if (!page) {
2579 ret = -ENOMEM;
2580 goto out_unlock;
2581 }
2582 if (!PageUptodate(page)) {
2583 btrfs_readpage(NULL, page);
2584 lock_page(page);
2585 if (!PageUptodate(page)) {
2586 unlock_page(page);
2587 page_cache_release(page);
2588 ret = -EIO;
2589 goto out_unlock;
2590 }
2591 }
2592 wait_on_page_writeback(page);
2593
2594 page_start = (u64)page->index << PAGE_CACHE_SHIFT;
2595 page_end = page_start + PAGE_CACHE_SIZE - 1;
2596 lock_extent(io_tree, page_start, page_end, GFP_NOFS);
2597
2598 ordered = btrfs_lookup_ordered_extent(inode, page_start);
2599 if (ordered) {
2600 unlock_extent(io_tree, page_start, page_end, GFP_NOFS);
2601 unlock_page(page);
2602 page_cache_release(page);
2603 btrfs_start_ordered_extent(inode, ordered, 1);
2604 btrfs_put_ordered_extent(ordered);
2605 goto again;
2606 }
2607 set_page_extent_mapped(page);
2608
2609 if (i == first_index)
2610 set_extent_bits(io_tree, page_start, page_end,
2611 EXTENT_BOUNDARY, GFP_NOFS);
2612 btrfs_set_extent_delalloc(inode, page_start, page_end);
2613
2614 set_page_dirty(page);
2615 total_dirty++;
2616
2617 unlock_extent(io_tree, page_start, page_end, GFP_NOFS);
2618 unlock_page(page);
2619 page_cache_release(page);
2620 }
2621 out_unlock:
2622 mutex_unlock(&inode->i_mutex);
2623 kfree(ra);
2624 balance_dirty_pages_ratelimited_nr(inode->i_mapping, total_dirty);
2625 return ret;
2626 }
2627
2628 static noinline_for_stack
2629 int relocate_data_extent(struct inode *inode, struct btrfs_key *extent_key)
2630 {
2631 struct btrfs_root *root = BTRFS_I(inode)->root;
2632 struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
2633 struct extent_map *em;
2634 u64 start = extent_key->objectid - BTRFS_I(inode)->index_cnt;
2635 u64 end = start + extent_key->offset - 1;
2636
2637 em = alloc_extent_map(GFP_NOFS);
2638 em->start = start;
2639 em->len = extent_key->offset;
2640 em->block_len = extent_key->offset;
2641 em->block_start = extent_key->objectid;
2642 em->bdev = root->fs_info->fs_devices->latest_bdev;
2643 set_bit(EXTENT_FLAG_PINNED, &em->flags);
2644
2645 /* setup extent map to cheat btrfs_readpage */
2646 lock_extent(&BTRFS_I(inode)->io_tree, start, end, GFP_NOFS);
2647 while (1) {
2648 int ret;
2649 spin_lock(&em_tree->lock);
2650 ret = add_extent_mapping(em_tree, em);
2651 spin_unlock(&em_tree->lock);
2652 if (ret != -EEXIST) {
2653 free_extent_map(em);
2654 break;
2655 }
2656 btrfs_drop_extent_cache(inode, start, end, 0);
2657 }
2658 unlock_extent(&BTRFS_I(inode)->io_tree, start, end, GFP_NOFS);
2659
2660 return relocate_inode_pages(inode, start, extent_key->offset);
2661 }
2662
2663 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
2664 static int get_ref_objectid_v0(struct reloc_control *rc,
2665 struct btrfs_path *path,
2666 struct btrfs_key *extent_key,
2667 u64 *ref_objectid, int *path_change)
2668 {
2669 struct btrfs_key key;
2670 struct extent_buffer *leaf;
2671 struct btrfs_extent_ref_v0 *ref0;
2672 int ret;
2673 int slot;
2674
2675 leaf = path->nodes[0];
2676 slot = path->slots[0];
2677 while (1) {
2678 if (slot >= btrfs_header_nritems(leaf)) {
2679 ret = btrfs_next_leaf(rc->extent_root, path);
2680 if (ret < 0)
2681 return ret;
2682 BUG_ON(ret > 0);
2683 leaf = path->nodes[0];
2684 slot = path->slots[0];
2685 if (path_change)
2686 *path_change = 1;
2687 }
2688 btrfs_item_key_to_cpu(leaf, &key, slot);
2689 if (key.objectid != extent_key->objectid)
2690 return -ENOENT;
2691
2692 if (key.type != BTRFS_EXTENT_REF_V0_KEY) {
2693 slot++;
2694 continue;
2695 }
2696 ref0 = btrfs_item_ptr(leaf, slot,
2697 struct btrfs_extent_ref_v0);
2698 *ref_objectid = btrfs_ref_objectid_v0(leaf, ref0);
2699 break;
2700 }
2701 return 0;
2702 }
2703 #endif
2704
2705 /*
2706 * helper to add a tree block to the list.
2707 * the major work is getting the generation and level of the block
2708 */
2709 static int add_tree_block(struct reloc_control *rc,
2710 struct btrfs_key *extent_key,
2711 struct btrfs_path *path,
2712 struct rb_root *blocks)
2713 {
2714 struct extent_buffer *eb;
2715 struct btrfs_extent_item *ei;
2716 struct btrfs_tree_block_info *bi;
2717 struct tree_block *block;
2718 struct rb_node *rb_node;
2719 u32 item_size;
2720 int level = -1;
2721 int generation;
2722
2723 eb = path->nodes[0];
2724 item_size = btrfs_item_size_nr(eb, path->slots[0]);
2725
2726 if (item_size >= sizeof(*ei) + sizeof(*bi)) {
2727 ei = btrfs_item_ptr(eb, path->slots[0],
2728 struct btrfs_extent_item);
2729 bi = (struct btrfs_tree_block_info *)(ei + 1);
2730 generation = btrfs_extent_generation(eb, ei);
2731 level = btrfs_tree_block_level(eb, bi);
2732 } else {
2733 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
2734 u64 ref_owner;
2735 int ret;
2736
2737 BUG_ON(item_size != sizeof(struct btrfs_extent_item_v0));
2738 ret = get_ref_objectid_v0(rc, path, extent_key,
2739 &ref_owner, NULL);
2740 BUG_ON(ref_owner >= BTRFS_MAX_LEVEL);
2741 level = (int)ref_owner;
2742 /* FIXME: get real generation */
2743 generation = 0;
2744 #else
2745 BUG();
2746 #endif
2747 }
2748
2749 btrfs_release_path(rc->extent_root, path);
2750
2751 BUG_ON(level == -1);
2752
2753 block = kmalloc(sizeof(*block), GFP_NOFS);
2754 if (!block)
2755 return -ENOMEM;
2756
2757 block->bytenr = extent_key->objectid;
2758 block->key.objectid = extent_key->offset;
2759 block->key.offset = generation;
2760 block->level = level;
2761 block->key_ready = 0;
2762
2763 rb_node = tree_insert(blocks, block->bytenr, &block->rb_node);
2764 BUG_ON(rb_node);
2765
2766 return 0;
2767 }
2768
2769 /*
2770 * helper to add tree blocks for backref of type BTRFS_SHARED_DATA_REF_KEY
2771 */
2772 static int __add_tree_block(struct reloc_control *rc,
2773 u64 bytenr, u32 blocksize,
2774 struct rb_root *blocks)
2775 {
2776 struct btrfs_path *path;
2777 struct btrfs_key key;
2778 int ret;
2779
2780 if (tree_block_processed(bytenr, blocksize, rc))
2781 return 0;
2782
2783 if (tree_search(blocks, bytenr))
2784 return 0;
2785
2786 path = btrfs_alloc_path();
2787 if (!path)
2788 return -ENOMEM;
2789
2790 key.objectid = bytenr;
2791 key.type = BTRFS_EXTENT_ITEM_KEY;
2792 key.offset = blocksize;
2793
2794 path->search_commit_root = 1;
2795 path->skip_locking = 1;
2796 ret = btrfs_search_slot(NULL, rc->extent_root, &key, path, 0, 0);
2797 if (ret < 0)
2798 goto out;
2799 BUG_ON(ret);
2800
2801 btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
2802 ret = add_tree_block(rc, &key, path, blocks);
2803 out:
2804 btrfs_free_path(path);
2805 return ret;
2806 }
2807
2808 /*
2809 * helper to check if the block use full backrefs for pointers in it
2810 */
2811 static int block_use_full_backref(struct reloc_control *rc,
2812 struct extent_buffer *eb)
2813 {
2814 struct btrfs_path *path;
2815 struct btrfs_extent_item *ei;
2816 struct btrfs_key key;
2817 u64 flags;
2818 int ret;
2819
2820 if (btrfs_header_flag(eb, BTRFS_HEADER_FLAG_RELOC) ||
2821 btrfs_header_backref_rev(eb) < BTRFS_MIXED_BACKREF_REV)
2822 return 1;
2823
2824 path = btrfs_alloc_path();
2825 BUG_ON(!path);
2826
2827 key.objectid = eb->start;
2828 key.type = BTRFS_EXTENT_ITEM_KEY;
2829 key.offset = eb->len;
2830
2831 path->search_commit_root = 1;
2832 path->skip_locking = 1;
2833 ret = btrfs_search_slot(NULL, rc->extent_root,
2834 &key, path, 0, 0);
2835 BUG_ON(ret);
2836
2837 ei = btrfs_item_ptr(path->nodes[0], path->slots[0],
2838 struct btrfs_extent_item);
2839 flags = btrfs_extent_flags(path->nodes[0], ei);
2840 BUG_ON(!(flags & BTRFS_EXTENT_FLAG_TREE_BLOCK));
2841 if (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF)
2842 ret = 1;
2843 else
2844 ret = 0;
2845 btrfs_free_path(path);
2846 return ret;
2847 }
2848
2849 /*
2850 * helper to add tree blocks for backref of type BTRFS_EXTENT_DATA_REF_KEY
2851 * this function scans fs tree to find blocks reference the data extent
2852 */
2853 static int find_data_references(struct reloc_control *rc,
2854 struct btrfs_key *extent_key,
2855 struct extent_buffer *leaf,
2856 struct btrfs_extent_data_ref *ref,
2857 struct rb_root *blocks)
2858 {
2859 struct btrfs_path *path;
2860 struct tree_block *block;
2861 struct btrfs_root *root;
2862 struct btrfs_file_extent_item *fi;
2863 struct rb_node *rb_node;
2864 struct btrfs_key key;
2865 u64 ref_root;
2866 u64 ref_objectid;
2867 u64 ref_offset;
2868 u32 ref_count;
2869 u32 nritems;
2870 int err = 0;
2871 int added = 0;
2872 int counted;
2873 int ret;
2874
2875 path = btrfs_alloc_path();
2876 if (!path)
2877 return -ENOMEM;
2878
2879 ref_root = btrfs_extent_data_ref_root(leaf, ref);
2880 ref_objectid = btrfs_extent_data_ref_objectid(leaf, ref);
2881 ref_offset = btrfs_extent_data_ref_offset(leaf, ref);
2882 ref_count = btrfs_extent_data_ref_count(leaf, ref);
2883
2884 root = read_fs_root(rc->extent_root->fs_info, ref_root);
2885 if (IS_ERR(root)) {
2886 err = PTR_ERR(root);
2887 goto out;
2888 }
2889
2890 key.objectid = ref_objectid;
2891 key.offset = ref_offset;
2892 key.type = BTRFS_EXTENT_DATA_KEY;
2893
2894 path->search_commit_root = 1;
2895 path->skip_locking = 1;
2896 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
2897 if (ret < 0) {
2898 err = ret;
2899 goto out;
2900 }
2901
2902 leaf = path->nodes[0];
2903 nritems = btrfs_header_nritems(leaf);
2904 /*
2905 * the references in tree blocks that use full backrefs
2906 * are not counted in
2907 */
2908 if (block_use_full_backref(rc, leaf))
2909 counted = 0;
2910 else
2911 counted = 1;
2912 rb_node = tree_search(blocks, leaf->start);
2913 if (rb_node) {
2914 if (counted)
2915 added = 1;
2916 else
2917 path->slots[0] = nritems;
2918 }
2919
2920 while (ref_count > 0) {
2921 while (path->slots[0] >= nritems) {
2922 ret = btrfs_next_leaf(root, path);
2923 if (ret < 0) {
2924 err = ret;
2925 goto out;
2926 }
2927 if (ret > 0) {
2928 WARN_ON(1);
2929 goto out;
2930 }
2931
2932 leaf = path->nodes[0];
2933 nritems = btrfs_header_nritems(leaf);
2934 added = 0;
2935
2936 if (block_use_full_backref(rc, leaf))
2937 counted = 0;
2938 else
2939 counted = 1;
2940 rb_node = tree_search(blocks, leaf->start);
2941 if (rb_node) {
2942 if (counted)
2943 added = 1;
2944 else
2945 path->slots[0] = nritems;
2946 }
2947 }
2948
2949 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
2950 if (key.objectid != ref_objectid ||
2951 key.type != BTRFS_EXTENT_DATA_KEY) {
2952 WARN_ON(1);
2953 break;
2954 }
2955
2956 fi = btrfs_item_ptr(leaf, path->slots[0],
2957 struct btrfs_file_extent_item);
2958
2959 if (btrfs_file_extent_type(leaf, fi) ==
2960 BTRFS_FILE_EXTENT_INLINE)
2961 goto next;
2962
2963 if (btrfs_file_extent_disk_bytenr(leaf, fi) !=
2964 extent_key->objectid)
2965 goto next;
2966
2967 key.offset -= btrfs_file_extent_offset(leaf, fi);
2968 if (key.offset != ref_offset)
2969 goto next;
2970
2971 if (counted)
2972 ref_count--;
2973 if (added)
2974 goto next;
2975
2976 if (!tree_block_processed(leaf->start, leaf->len, rc)) {
2977 block = kmalloc(sizeof(*block), GFP_NOFS);
2978 if (!block) {
2979 err = -ENOMEM;
2980 break;
2981 }
2982 block->bytenr = leaf->start;
2983 btrfs_item_key_to_cpu(leaf, &block->key, 0);
2984 block->level = 0;
2985 block->key_ready = 1;
2986 rb_node = tree_insert(blocks, block->bytenr,
2987 &block->rb_node);
2988 BUG_ON(rb_node);
2989 }
2990 if (counted)
2991 added = 1;
2992 else
2993 path->slots[0] = nritems;
2994 next:
2995 path->slots[0]++;
2996
2997 }
2998 out:
2999 btrfs_free_path(path);
3000 return err;
3001 }
3002
3003 /*
3004 * hepler to find all tree blocks that reference a given data extent
3005 */
3006 static noinline_for_stack
3007 int add_data_references(struct reloc_control *rc,
3008 struct btrfs_key *extent_key,
3009 struct btrfs_path *path,
3010 struct rb_root *blocks)
3011 {
3012 struct btrfs_key key;
3013 struct extent_buffer *eb;
3014 struct btrfs_extent_data_ref *dref;
3015 struct btrfs_extent_inline_ref *iref;
3016 unsigned long ptr;
3017 unsigned long end;
3018 u32 blocksize;
3019 int ret;
3020 int err = 0;
3021
3022 ret = get_new_location(rc->data_inode, NULL, extent_key->objectid,
3023 extent_key->offset);
3024 BUG_ON(ret < 0);
3025 if (ret > 0) {
3026 /* the relocated data is fragmented */
3027 rc->extents_skipped++;
3028 btrfs_release_path(rc->extent_root, path);
3029 return 0;
3030 }
3031
3032 blocksize = btrfs_level_size(rc->extent_root, 0);
3033
3034 eb = path->nodes[0];
3035 ptr = btrfs_item_ptr_offset(eb, path->slots[0]);
3036 end = ptr + btrfs_item_size_nr(eb, path->slots[0]);
3037 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
3038 if (ptr + sizeof(struct btrfs_extent_item_v0) == end)
3039 ptr = end;
3040 else
3041 #endif
3042 ptr += sizeof(struct btrfs_extent_item);
3043
3044 while (ptr < end) {
3045 iref = (struct btrfs_extent_inline_ref *)ptr;
3046 key.type = btrfs_extent_inline_ref_type(eb, iref);
3047 if (key.type == BTRFS_SHARED_DATA_REF_KEY) {
3048 key.offset = btrfs_extent_inline_ref_offset(eb, iref);
3049 ret = __add_tree_block(rc, key.offset, blocksize,
3050 blocks);
3051 } else if (key.type == BTRFS_EXTENT_DATA_REF_KEY) {
3052 dref = (struct btrfs_extent_data_ref *)(&iref->offset);
3053 ret = find_data_references(rc, extent_key,
3054 eb, dref, blocks);
3055 } else {
3056 BUG();
3057 }
3058 ptr += btrfs_extent_inline_ref_size(key.type);
3059 }
3060 WARN_ON(ptr > end);
3061
3062 while (1) {
3063 cond_resched();
3064 eb = path->nodes[0];
3065 if (path->slots[0] >= btrfs_header_nritems(eb)) {
3066 ret = btrfs_next_leaf(rc->extent_root, path);
3067 if (ret < 0) {
3068 err = ret;
3069 break;
3070 }
3071 if (ret > 0)
3072 break;
3073 eb = path->nodes[0];
3074 }
3075
3076 btrfs_item_key_to_cpu(eb, &key, path->slots[0]);
3077 if (key.objectid != extent_key->objectid)
3078 break;
3079
3080 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
3081 if (key.type == BTRFS_SHARED_DATA_REF_KEY ||
3082 key.type == BTRFS_EXTENT_REF_V0_KEY) {
3083 #else
3084 BUG_ON(key.type == BTRFS_EXTENT_REF_V0_KEY);
3085 if (key.type == BTRFS_SHARED_DATA_REF_KEY) {
3086 #endif
3087 ret = __add_tree_block(rc, key.offset, blocksize,
3088 blocks);
3089 } else if (key.type == BTRFS_EXTENT_DATA_REF_KEY) {
3090 dref = btrfs_item_ptr(eb, path->slots[0],
3091 struct btrfs_extent_data_ref);
3092 ret = find_data_references(rc, extent_key,
3093 eb, dref, blocks);
3094 } else {
3095 ret = 0;
3096 }
3097 if (ret) {
3098 err = ret;
3099 break;
3100 }
3101 path->slots[0]++;
3102 }
3103 btrfs_release_path(rc->extent_root, path);
3104 if (err)
3105 free_block_list(blocks);
3106 return err;
3107 }
3108
3109 /*
3110 * hepler to find next unprocessed extent
3111 */
3112 static noinline_for_stack
3113 int find_next_extent(struct btrfs_trans_handle *trans,
3114 struct reloc_control *rc, struct btrfs_path *path)
3115 {
3116 struct btrfs_key key;
3117 struct extent_buffer *leaf;
3118 u64 start, end, last;
3119 int ret;
3120
3121 last = rc->block_group->key.objectid + rc->block_group->key.offset;
3122 while (1) {
3123 cond_resched();
3124 if (rc->search_start >= last) {
3125 ret = 1;
3126 break;
3127 }
3128
3129 key.objectid = rc->search_start;
3130 key.type = BTRFS_EXTENT_ITEM_KEY;
3131 key.offset = 0;
3132
3133 path->search_commit_root = 1;
3134 path->skip_locking = 1;
3135 ret = btrfs_search_slot(NULL, rc->extent_root, &key, path,
3136 0, 0);
3137 if (ret < 0)
3138 break;
3139 next:
3140 leaf = path->nodes[0];
3141 if (path->slots[0] >= btrfs_header_nritems(leaf)) {
3142 ret = btrfs_next_leaf(rc->extent_root, path);
3143 if (ret != 0)
3144 break;
3145 leaf = path->nodes[0];
3146 }
3147
3148 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
3149 if (key.objectid >= last) {
3150 ret = 1;
3151 break;
3152 }
3153
3154 if (key.type != BTRFS_EXTENT_ITEM_KEY ||
3155 key.objectid + key.offset <= rc->search_start) {
3156 path->slots[0]++;
3157 goto next;
3158 }
3159
3160 ret = find_first_extent_bit(&rc->processed_blocks,
3161 key.objectid, &start, &end,
3162 EXTENT_DIRTY);
3163
3164 if (ret == 0 && start <= key.objectid) {
3165 btrfs_release_path(rc->extent_root, path);
3166 rc->search_start = end + 1;
3167 } else {
3168 rc->search_start = key.objectid + key.offset;
3169 return 0;
3170 }
3171 }
3172 btrfs_release_path(rc->extent_root, path);
3173 return ret;
3174 }
3175
3176 static void set_reloc_control(struct reloc_control *rc)
3177 {
3178 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
3179 mutex_lock(&fs_info->trans_mutex);
3180 fs_info->reloc_ctl = rc;
3181 mutex_unlock(&fs_info->trans_mutex);
3182 }
3183
3184 static void unset_reloc_control(struct reloc_control *rc)
3185 {
3186 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
3187 mutex_lock(&fs_info->trans_mutex);
3188 fs_info->reloc_ctl = NULL;
3189 mutex_unlock(&fs_info->trans_mutex);
3190 }
3191
3192 static int check_extent_flags(u64 flags)
3193 {
3194 if ((flags & BTRFS_EXTENT_FLAG_DATA) &&
3195 (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK))
3196 return 1;
3197 if (!(flags & BTRFS_EXTENT_FLAG_DATA) &&
3198 !(flags & BTRFS_EXTENT_FLAG_TREE_BLOCK))
3199 return 1;
3200 if ((flags & BTRFS_EXTENT_FLAG_DATA) &&
3201 (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF))
3202 return 1;
3203 return 0;
3204 }
3205
3206 static noinline_for_stack int relocate_block_group(struct reloc_control *rc)
3207 {
3208 struct rb_root blocks = RB_ROOT;
3209 struct btrfs_key key;
3210 struct btrfs_trans_handle *trans = NULL;
3211 struct btrfs_path *path;
3212 struct btrfs_extent_item *ei;
3213 unsigned long nr;
3214 u64 flags;
3215 u32 item_size;
3216 int ret;
3217 int err = 0;
3218
3219 path = btrfs_alloc_path();
3220 if (!path)
3221 return -ENOMEM;
3222
3223 rc->search_start = rc->block_group->key.objectid;
3224 clear_extent_bits(&rc->processed_blocks, 0, (u64)-1, EXTENT_DIRTY,
3225 GFP_NOFS);
3226
3227 rc->create_reloc_root = 1;
3228 set_reloc_control(rc);
3229
3230 trans = btrfs_start_transaction(rc->extent_root, 1);
3231 btrfs_commit_transaction(trans, rc->extent_root);
3232
3233 while (1) {
3234 trans = btrfs_start_transaction(rc->extent_root, 1);
3235
3236 ret = find_next_extent(trans, rc, path);
3237 if (ret < 0)
3238 err = ret;
3239 if (ret != 0)
3240 break;
3241
3242 rc->extents_found++;
3243
3244 ei = btrfs_item_ptr(path->nodes[0], path->slots[0],
3245 struct btrfs_extent_item);
3246 btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
3247 item_size = btrfs_item_size_nr(path->nodes[0],
3248 path->slots[0]);
3249 if (item_size >= sizeof(*ei)) {
3250 flags = btrfs_extent_flags(path->nodes[0], ei);
3251 ret = check_extent_flags(flags);
3252 BUG_ON(ret);
3253
3254 } else {
3255 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
3256 u64 ref_owner;
3257 int path_change = 0;
3258
3259 BUG_ON(item_size !=
3260 sizeof(struct btrfs_extent_item_v0));
3261 ret = get_ref_objectid_v0(rc, path, &key, &ref_owner,
3262 &path_change);
3263 if (ref_owner < BTRFS_FIRST_FREE_OBJECTID)
3264 flags = BTRFS_EXTENT_FLAG_TREE_BLOCK;
3265 else
3266 flags = BTRFS_EXTENT_FLAG_DATA;
3267
3268 if (path_change) {
3269 btrfs_release_path(rc->extent_root, path);
3270
3271 path->search_commit_root = 1;
3272 path->skip_locking = 1;
3273 ret = btrfs_search_slot(NULL, rc->extent_root,
3274 &key, path, 0, 0);
3275 if (ret < 0) {
3276 err = ret;
3277 break;
3278 }
3279 BUG_ON(ret > 0);
3280 }
3281 #else
3282 BUG();
3283 #endif
3284 }
3285
3286 if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) {
3287 ret = add_tree_block(rc, &key, path, &blocks);
3288 } else if (rc->stage == UPDATE_DATA_PTRS &&
3289 (flags & BTRFS_EXTENT_FLAG_DATA)) {
3290 ret = add_data_references(rc, &key, path, &blocks);
3291 } else {
3292 btrfs_release_path(rc->extent_root, path);
3293 ret = 0;
3294 }
3295 if (ret < 0) {
3296 err = 0;
3297 break;
3298 }
3299
3300 if (!RB_EMPTY_ROOT(&blocks)) {
3301 ret = relocate_tree_blocks(trans, rc, &blocks);
3302 if (ret < 0) {
3303 err = ret;
3304 break;
3305 }
3306 }
3307
3308 nr = trans->blocks_used;
3309 btrfs_end_transaction_throttle(trans, rc->extent_root);
3310 trans = NULL;
3311 btrfs_btree_balance_dirty(rc->extent_root, nr);
3312
3313 if (rc->stage == MOVE_DATA_EXTENTS &&
3314 (flags & BTRFS_EXTENT_FLAG_DATA)) {
3315 rc->found_file_extent = 1;
3316 ret = relocate_data_extent(rc->data_inode, &key);
3317 if (ret < 0) {
3318 err = ret;
3319 break;
3320 }
3321 }
3322 }
3323 btrfs_free_path(path);
3324
3325 if (trans) {
3326 nr = trans->blocks_used;
3327 btrfs_end_transaction(trans, rc->extent_root);
3328 btrfs_btree_balance_dirty(rc->extent_root, nr);
3329 }
3330
3331 rc->create_reloc_root = 0;
3332 smp_mb();
3333
3334 if (rc->extents_found > 0) {
3335 trans = btrfs_start_transaction(rc->extent_root, 1);
3336 btrfs_commit_transaction(trans, rc->extent_root);
3337 }
3338
3339 merge_reloc_roots(rc);
3340
3341 unset_reloc_control(rc);
3342
3343 /* get rid of pinned extents */
3344 trans = btrfs_start_transaction(rc->extent_root, 1);
3345 btrfs_commit_transaction(trans, rc->extent_root);
3346
3347 return err;
3348 }
3349
3350 static int __insert_orphan_inode(struct btrfs_trans_handle *trans,
3351 struct btrfs_root *root,
3352 u64 objectid, u64 size)
3353 {
3354 struct btrfs_path *path;
3355 struct btrfs_inode_item *item;
3356 struct extent_buffer *leaf;
3357 int ret;
3358
3359 path = btrfs_alloc_path();
3360 if (!path)
3361 return -ENOMEM;
3362
3363 ret = btrfs_insert_empty_inode(trans, root, path, objectid);
3364 if (ret)
3365 goto out;
3366
3367 leaf = path->nodes[0];
3368 item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_inode_item);
3369 memset_extent_buffer(leaf, 0, (unsigned long)item, sizeof(*item));
3370 btrfs_set_inode_generation(leaf, item, 1);
3371 btrfs_set_inode_size(leaf, item, size);
3372 btrfs_set_inode_mode(leaf, item, S_IFREG | 0600);
3373 btrfs_set_inode_flags(leaf, item, BTRFS_INODE_NOCOMPRESS);
3374 btrfs_mark_buffer_dirty(leaf);
3375 btrfs_release_path(root, path);
3376 out:
3377 btrfs_free_path(path);
3378 return ret;
3379 }
3380
3381 /*
3382 * helper to create inode for data relocation.
3383 * the inode is in data relocation tree and its link count is 0
3384 */
3385 static struct inode *create_reloc_inode(struct btrfs_fs_info *fs_info,
3386 struct btrfs_block_group_cache *group)
3387 {
3388 struct inode *inode = NULL;
3389 struct btrfs_trans_handle *trans;
3390 struct btrfs_root *root;
3391 struct btrfs_key key;
3392 unsigned long nr;
3393 u64 objectid = BTRFS_FIRST_FREE_OBJECTID;
3394 int err = 0;
3395
3396 root = read_fs_root(fs_info, BTRFS_DATA_RELOC_TREE_OBJECTID);
3397 if (IS_ERR(root))
3398 return ERR_CAST(root);
3399
3400 trans = btrfs_start_transaction(root, 1);
3401 BUG_ON(!trans);
3402
3403 err = btrfs_find_free_objectid(trans, root, objectid, &objectid);
3404 if (err)
3405 goto out;
3406
3407 err = __insert_orphan_inode(trans, root, objectid, group->key.offset);
3408 BUG_ON(err);
3409
3410 err = btrfs_insert_file_extent(trans, root, objectid, 0, 0, 0,
3411 group->key.offset, 0, group->key.offset,
3412 0, 0, 0);
3413 BUG_ON(err);
3414
3415 key.objectid = objectid;
3416 key.type = BTRFS_INODE_ITEM_KEY;
3417 key.offset = 0;
3418 inode = btrfs_iget(root->fs_info->sb, &key, root);
3419 BUG_ON(IS_ERR(inode) || is_bad_inode(inode));
3420 BTRFS_I(inode)->index_cnt = group->key.objectid;
3421
3422 err = btrfs_orphan_add(trans, inode);
3423 out:
3424 nr = trans->blocks_used;
3425 btrfs_end_transaction(trans, root);
3426
3427 btrfs_btree_balance_dirty(root, nr);
3428 if (err) {
3429 if (inode)
3430 iput(inode);
3431 inode = ERR_PTR(err);
3432 }
3433 return inode;
3434 }
3435
3436 /*
3437 * function to relocate all extents in a block group.
3438 */
3439 int btrfs_relocate_block_group(struct btrfs_root *extent_root, u64 group_start)
3440 {
3441 struct btrfs_fs_info *fs_info = extent_root->fs_info;
3442 struct reloc_control *rc;
3443 int ret;
3444 int err = 0;
3445
3446 rc = kzalloc(sizeof(*rc), GFP_NOFS);
3447 if (!rc)
3448 return -ENOMEM;
3449
3450 mapping_tree_init(&rc->reloc_root_tree);
3451 extent_io_tree_init(&rc->processed_blocks, NULL, GFP_NOFS);
3452 INIT_LIST_HEAD(&rc->reloc_roots);
3453
3454 rc->block_group = btrfs_lookup_block_group(fs_info, group_start);
3455 BUG_ON(!rc->block_group);
3456
3457 btrfs_init_workers(&rc->workers, "relocate",
3458 fs_info->thread_pool_size);
3459
3460 rc->extent_root = extent_root;
3461 btrfs_prepare_block_group_relocation(extent_root, rc->block_group);
3462
3463 rc->data_inode = create_reloc_inode(fs_info, rc->block_group);
3464 if (IS_ERR(rc->data_inode)) {
3465 err = PTR_ERR(rc->data_inode);
3466 rc->data_inode = NULL;
3467 goto out;
3468 }
3469
3470 printk(KERN_INFO "btrfs: relocating block group %llu flags %llu\n",
3471 (unsigned long long)rc->block_group->key.objectid,
3472 (unsigned long long)rc->block_group->flags);
3473
3474 btrfs_start_delalloc_inodes(fs_info->tree_root);
3475 btrfs_wait_ordered_extents(fs_info->tree_root, 0);
3476
3477 while (1) {
3478 mutex_lock(&fs_info->cleaner_mutex);
3479 btrfs_clean_old_snapshots(fs_info->tree_root);
3480 mutex_unlock(&fs_info->cleaner_mutex);
3481
3482 rc->extents_found = 0;
3483 rc->extents_skipped = 0;
3484
3485 ret = relocate_block_group(rc);
3486 if (ret < 0) {
3487 err = ret;
3488 break;
3489 }
3490
3491 if (rc->extents_found == 0)
3492 break;
3493
3494 printk(KERN_INFO "btrfs: found %llu extents\n",
3495 (unsigned long long)rc->extents_found);
3496
3497 if (rc->stage == MOVE_DATA_EXTENTS && rc->found_file_extent) {
3498 btrfs_wait_ordered_range(rc->data_inode, 0, (u64)-1);
3499 invalidate_mapping_pages(rc->data_inode->i_mapping,
3500 0, -1);
3501 rc->stage = UPDATE_DATA_PTRS;
3502 } else if (rc->stage == UPDATE_DATA_PTRS &&
3503 rc->extents_skipped >= rc->extents_found) {
3504 iput(rc->data_inode);
3505 rc->data_inode = create_reloc_inode(fs_info,
3506 rc->block_group);
3507 if (IS_ERR(rc->data_inode)) {
3508 err = PTR_ERR(rc->data_inode);
3509 rc->data_inode = NULL;
3510 break;
3511 }
3512 rc->stage = MOVE_DATA_EXTENTS;
3513 rc->found_file_extent = 0;
3514 }
3515 }
3516
3517 filemap_fdatawrite_range(fs_info->btree_inode->i_mapping,
3518 rc->block_group->key.objectid,
3519 rc->block_group->key.objectid +
3520 rc->block_group->key.offset - 1);
3521
3522 WARN_ON(rc->block_group->pinned > 0);
3523 WARN_ON(rc->block_group->reserved > 0);
3524 WARN_ON(btrfs_block_group_used(&rc->block_group->item) > 0);
3525 out:
3526 iput(rc->data_inode);
3527 btrfs_stop_workers(&rc->workers);
3528 btrfs_put_block_group(rc->block_group);
3529 kfree(rc);
3530 return err;
3531 }
3532
3533 /*
3534 * recover relocation interrupted by system crash.
3535 *
3536 * this function resumes merging reloc trees with corresponding fs trees.
3537 * this is important for keeping the sharing of tree blocks
3538 */
3539 int btrfs_recover_relocation(struct btrfs_root *root)
3540 {
3541 LIST_HEAD(reloc_roots);
3542 struct btrfs_key key;
3543 struct btrfs_root *fs_root;
3544 struct btrfs_root *reloc_root;
3545 struct btrfs_path *path;
3546 struct extent_buffer *leaf;
3547 struct reloc_control *rc = NULL;
3548 struct btrfs_trans_handle *trans;
3549 int ret;
3550 int err = 0;
3551
3552 path = btrfs_alloc_path();
3553 if (!path)
3554 return -ENOMEM;
3555
3556 key.objectid = BTRFS_TREE_RELOC_OBJECTID;
3557 key.type = BTRFS_ROOT_ITEM_KEY;
3558 key.offset = (u64)-1;
3559
3560 while (1) {
3561 ret = btrfs_search_slot(NULL, root->fs_info->tree_root, &key,
3562 path, 0, 0);
3563 if (ret < 0) {
3564 err = ret;
3565 goto out;
3566 }
3567 if (ret > 0) {
3568 if (path->slots[0] == 0)
3569 break;
3570 path->slots[0]--;
3571 }
3572 leaf = path->nodes[0];
3573 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
3574 btrfs_release_path(root->fs_info->tree_root, path);
3575
3576 if (key.objectid != BTRFS_TREE_RELOC_OBJECTID ||
3577 key.type != BTRFS_ROOT_ITEM_KEY)
3578 break;
3579
3580 reloc_root = btrfs_read_fs_root_no_radix(root, &key);
3581 if (IS_ERR(reloc_root)) {
3582 err = PTR_ERR(reloc_root);
3583 goto out;
3584 }
3585
3586 list_add(&reloc_root->root_list, &reloc_roots);
3587
3588 if (btrfs_root_refs(&reloc_root->root_item) > 0) {
3589 fs_root = read_fs_root(root->fs_info,
3590 reloc_root->root_key.offset);
3591 if (IS_ERR(fs_root)) {
3592 err = PTR_ERR(fs_root);
3593 goto out;
3594 }
3595 }
3596
3597 if (key.offset == 0)
3598 break;
3599
3600 key.offset--;
3601 }
3602 btrfs_release_path(root->fs_info->tree_root, path);
3603
3604 if (list_empty(&reloc_roots))
3605 goto out;
3606
3607 rc = kzalloc(sizeof(*rc), GFP_NOFS);
3608 if (!rc) {
3609 err = -ENOMEM;
3610 goto out;
3611 }
3612
3613 mapping_tree_init(&rc->reloc_root_tree);
3614 INIT_LIST_HEAD(&rc->reloc_roots);
3615 btrfs_init_workers(&rc->workers, "relocate",
3616 root->fs_info->thread_pool_size);
3617 rc->extent_root = root->fs_info->extent_root;
3618
3619 set_reloc_control(rc);
3620
3621 while (!list_empty(&reloc_roots)) {
3622 reloc_root = list_entry(reloc_roots.next,
3623 struct btrfs_root, root_list);
3624 list_del(&reloc_root->root_list);
3625
3626 if (btrfs_root_refs(&reloc_root->root_item) == 0) {
3627 list_add_tail(&reloc_root->root_list,
3628 &rc->reloc_roots);
3629 continue;
3630 }
3631
3632 fs_root = read_fs_root(root->fs_info,
3633 reloc_root->root_key.offset);
3634 BUG_ON(IS_ERR(fs_root));
3635
3636 __add_reloc_root(reloc_root);
3637 fs_root->reloc_root = reloc_root;
3638 }
3639
3640 trans = btrfs_start_transaction(rc->extent_root, 1);
3641 btrfs_commit_transaction(trans, rc->extent_root);
3642
3643 merge_reloc_roots(rc);
3644
3645 unset_reloc_control(rc);
3646
3647 trans = btrfs_start_transaction(rc->extent_root, 1);
3648 btrfs_commit_transaction(trans, rc->extent_root);
3649 out:
3650 if (rc) {
3651 btrfs_stop_workers(&rc->workers);
3652 kfree(rc);
3653 }
3654 while (!list_empty(&reloc_roots)) {
3655 reloc_root = list_entry(reloc_roots.next,
3656 struct btrfs_root, root_list);
3657 list_del(&reloc_root->root_list);
3658 free_extent_buffer(reloc_root->node);
3659 free_extent_buffer(reloc_root->commit_root);
3660 kfree(reloc_root);
3661 }
3662 btrfs_free_path(path);
3663
3664 if (err == 0) {
3665 /* cleanup orphan inode in data relocation tree */
3666 fs_root = read_fs_root(root->fs_info,
3667 BTRFS_DATA_RELOC_TREE_OBJECTID);
3668 if (IS_ERR(fs_root))
3669 err = PTR_ERR(fs_root);
3670 }
3671 return err;
3672 }
3673
3674 /*
3675 * helper to add ordered checksum for data relocation.
3676 *
3677 * cloning checksum properly handles the nodatasum extents.
3678 * it also saves CPU time to re-calculate the checksum.
3679 */
3680 int btrfs_reloc_clone_csums(struct inode *inode, u64 file_pos, u64 len)
3681 {
3682 struct btrfs_ordered_sum *sums;
3683 struct btrfs_sector_sum *sector_sum;
3684 struct btrfs_ordered_extent *ordered;
3685 struct btrfs_root *root = BTRFS_I(inode)->root;
3686 size_t offset;
3687 int ret;
3688 u64 disk_bytenr;
3689 LIST_HEAD(list);
3690
3691 ordered = btrfs_lookup_ordered_extent(inode, file_pos);
3692 BUG_ON(ordered->file_offset != file_pos || ordered->len != len);
3693
3694 disk_bytenr = file_pos + BTRFS_I(inode)->index_cnt;
3695 ret = btrfs_lookup_csums_range(root->fs_info->csum_root, disk_bytenr,
3696 disk_bytenr + len - 1, &list);
3697
3698 while (!list_empty(&list)) {
3699 sums = list_entry(list.next, struct btrfs_ordered_sum, list);
3700 list_del_init(&sums->list);
3701
3702 sector_sum = sums->sums;
3703 sums->bytenr = ordered->start;
3704
3705 offset = 0;
3706 while (offset < sums->len) {
3707 sector_sum->bytenr += ordered->start - disk_bytenr;
3708 sector_sum++;
3709 offset += root->sectorsize;
3710 }
3711
3712 btrfs_add_ordered_sum(inode, ordered, sums);
3713 }
3714 btrfs_put_ordered_extent(ordered);
3715 return 0;
3716 }
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