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On Tue, Nov 06, 2007 at 02:33:53AM -0800, akpm@linux-foundation.org wrote:
[mmotm.git] / fs / btrfs / relocation.c
blobcfcc93c93a7b4db99b87ef3b91b30cc8d2f7e36b
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 #define MAX_EXTENTS 128
125
126 struct file_extent_cluster {
127 u64 start;
128 u64 end;
129 u64 boundary[MAX_EXTENTS];
130 unsigned int nr;
131 };
132
133 struct reloc_control {
134 /* block group to relocate */
135 struct btrfs_block_group_cache *block_group;
136 /* extent tree */
137 struct btrfs_root *extent_root;
138 /* inode for moving data */
139 struct inode *data_inode;
140 struct btrfs_workers workers;
141 /* tree blocks have been processed */
142 struct extent_io_tree processed_blocks;
143 /* map start of tree root to corresponding reloc tree */
144 struct mapping_tree reloc_root_tree;
145 /* list of reloc trees */
146 struct list_head reloc_roots;
147 u64 search_start;
148 u64 extents_found;
149 u64 extents_skipped;
150 int stage;
151 int create_reloc_root;
152 unsigned int found_file_extent:1;
153 unsigned int found_old_snapshot:1;
154 };
155
156 /* stages of data relocation */
157 #define MOVE_DATA_EXTENTS 0
158 #define UPDATE_DATA_PTRS 1
159
160 /*
161 * merge reloc tree to corresponding fs tree in worker threads
162 */
163 struct async_merge {
164 struct btrfs_work work;
165 struct reloc_control *rc;
166 struct btrfs_root *root;
167 struct completion *done;
168 atomic_t *num_pending;
169 };
170
171 static void mapping_tree_init(struct mapping_tree *tree)
172 {
173 tree->rb_root.rb_node = NULL;
174 spin_lock_init(&tree->lock);
175 }
176
177 static void backref_cache_init(struct backref_cache *cache)
178 {
179 int i;
180 cache->rb_root.rb_node = NULL;
181 for (i = 0; i < BTRFS_MAX_LEVEL; i++)
182 INIT_LIST_HEAD(&cache->pending[i]);
183 spin_lock_init(&cache->lock);
184 }
185
186 static void backref_node_init(struct backref_node *node)
187 {
188 memset(node, 0, sizeof(*node));
189 INIT_LIST_HEAD(&node->upper);
190 INIT_LIST_HEAD(&node->lower);
191 RB_CLEAR_NODE(&node->rb_node);
192 }
193
194 static struct rb_node *tree_insert(struct rb_root *root, u64 bytenr,
195 struct rb_node *node)
196 {
197 struct rb_node **p = &root->rb_node;
198 struct rb_node *parent = NULL;
199 struct tree_entry *entry;
200
201 while (*p) {
202 parent = *p;
203 entry = rb_entry(parent, struct tree_entry, rb_node);
204
205 if (bytenr < entry->bytenr)
206 p = &(*p)->rb_left;
207 else if (bytenr > entry->bytenr)
208 p = &(*p)->rb_right;
209 else
210 return parent;
211 }
212
213 rb_link_node(node, parent, p);
214 rb_insert_color(node, root);
215 return NULL;
216 }
217
218 static struct rb_node *tree_search(struct rb_root *root, u64 bytenr)
219 {
220 struct rb_node *n = root->rb_node;
221 struct tree_entry *entry;
222
223 while (n) {
224 entry = rb_entry(n, struct tree_entry, rb_node);
225
226 if (bytenr < entry->bytenr)
227 n = n->rb_left;
228 else if (bytenr > entry->bytenr)
229 n = n->rb_right;
230 else
231 return n;
232 }
233 return NULL;
234 }
235
236 /*
237 * walk up backref nodes until reach node presents tree root
238 */
239 static struct backref_node *walk_up_backref(struct backref_node *node,
240 struct backref_edge *edges[],
241 int *index)
242 {
243 struct backref_edge *edge;
244 int idx = *index;
245
246 while (!list_empty(&node->upper)) {
247 edge = list_entry(node->upper.next,
248 struct backref_edge, list[LOWER]);
249 edges[idx++] = edge;
250 node = edge->node[UPPER];
251 }
252 *index = idx;
253 return node;
254 }
255
256 /*
257 * walk down backref nodes to find start of next reference path
258 */
259 static struct backref_node *walk_down_backref(struct backref_edge *edges[],
260 int *index)
261 {
262 struct backref_edge *edge;
263 struct backref_node *lower;
264 int idx = *index;
265
266 while (idx > 0) {
267 edge = edges[idx - 1];
268 lower = edge->node[LOWER];
269 if (list_is_last(&edge->list[LOWER], &lower->upper)) {
270 idx--;
271 continue;
272 }
273 edge = list_entry(edge->list[LOWER].next,
274 struct backref_edge, list[LOWER]);
275 edges[idx - 1] = edge;
276 *index = idx;
277 return edge->node[UPPER];
278 }
279 *index = 0;
280 return NULL;
281 }
282
283 static void drop_node_buffer(struct backref_node *node)
284 {
285 if (node->eb) {
286 if (node->locked) {
287 btrfs_tree_unlock(node->eb);
288 node->locked = 0;
289 }
290 free_extent_buffer(node->eb);
291 node->eb = NULL;
292 }
293 }
294
295 static void drop_backref_node(struct backref_cache *tree,
296 struct backref_node *node)
297 {
298 BUG_ON(!node->lowest);
299 BUG_ON(!list_empty(&node->upper));
300
301 drop_node_buffer(node);
302 list_del(&node->lower);
303
304 rb_erase(&node->rb_node, &tree->rb_root);
305 kfree(node);
306 }
307
308 /*
309 * remove a backref node from the backref cache
310 */
311 static void remove_backref_node(struct backref_cache *cache,
312 struct backref_node *node)
313 {
314 struct backref_node *upper;
315 struct backref_edge *edge;
316
317 if (!node)
318 return;
319
320 BUG_ON(!node->lowest);
321 while (!list_empty(&node->upper)) {
322 edge = list_entry(node->upper.next, struct backref_edge,
323 list[LOWER]);
324 upper = edge->node[UPPER];
325 list_del(&edge->list[LOWER]);
326 list_del(&edge->list[UPPER]);
327 kfree(edge);
328 /*
329 * add the node to pending list if no other
330 * child block cached.
331 */
332 if (list_empty(&upper->lower)) {
333 list_add_tail(&upper->lower,
334 &cache->pending[upper->level]);
335 upper->lowest = 1;
336 }
337 }
338 drop_backref_node(cache, node);
339 }
340
341 /*
342 * find reloc tree by address of tree root
343 */
344 static struct btrfs_root *find_reloc_root(struct reloc_control *rc,
345 u64 bytenr)
346 {
347 struct rb_node *rb_node;
348 struct mapping_node *node;
349 struct btrfs_root *root = NULL;
350
351 spin_lock(&rc->reloc_root_tree.lock);
352 rb_node = tree_search(&rc->reloc_root_tree.rb_root, bytenr);
353 if (rb_node) {
354 node = rb_entry(rb_node, struct mapping_node, rb_node);
355 root = (struct btrfs_root *)node->data;
356 }
357 spin_unlock(&rc->reloc_root_tree.lock);
358 return root;
359 }
360
361 static int is_cowonly_root(u64 root_objectid)
362 {
363 if (root_objectid == BTRFS_ROOT_TREE_OBJECTID ||
364 root_objectid == BTRFS_EXTENT_TREE_OBJECTID ||
365 root_objectid == BTRFS_CHUNK_TREE_OBJECTID ||
366 root_objectid == BTRFS_DEV_TREE_OBJECTID ||
367 root_objectid == BTRFS_TREE_LOG_OBJECTID ||
368 root_objectid == BTRFS_CSUM_TREE_OBJECTID)
369 return 1;
370 return 0;
371 }
372
373 static struct btrfs_root *read_fs_root(struct btrfs_fs_info *fs_info,
374 u64 root_objectid)
375 {
376 struct btrfs_key key;
377
378 key.objectid = root_objectid;
379 key.type = BTRFS_ROOT_ITEM_KEY;
380 if (is_cowonly_root(root_objectid))
381 key.offset = 0;
382 else
383 key.offset = (u64)-1;
384
385 return btrfs_read_fs_root_no_name(fs_info, &key);
386 }
387
388 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
389 static noinline_for_stack
390 struct btrfs_root *find_tree_root(struct reloc_control *rc,
391 struct extent_buffer *leaf,
392 struct btrfs_extent_ref_v0 *ref0)
393 {
394 struct btrfs_root *root;
395 u64 root_objectid = btrfs_ref_root_v0(leaf, ref0);
396 u64 generation = btrfs_ref_generation_v0(leaf, ref0);
397
398 BUG_ON(root_objectid == BTRFS_TREE_RELOC_OBJECTID);
399
400 root = read_fs_root(rc->extent_root->fs_info, root_objectid);
401 BUG_ON(IS_ERR(root));
402
403 if (root->ref_cows &&
404 generation != btrfs_root_generation(&root->root_item))
405 return NULL;
406
407 return root;
408 }
409 #endif
410
411 static noinline_for_stack
412 int find_inline_backref(struct extent_buffer *leaf, int slot,
413 unsigned long *ptr, unsigned long *end)
414 {
415 struct btrfs_extent_item *ei;
416 struct btrfs_tree_block_info *bi;
417 u32 item_size;
418
419 item_size = btrfs_item_size_nr(leaf, slot);
420 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
421 if (item_size < sizeof(*ei)) {
422 WARN_ON(item_size != sizeof(struct btrfs_extent_item_v0));
423 return 1;
424 }
425 #endif
426 ei = btrfs_item_ptr(leaf, slot, struct btrfs_extent_item);
427 WARN_ON(!(btrfs_extent_flags(leaf, ei) &
428 BTRFS_EXTENT_FLAG_TREE_BLOCK));
429
430 if (item_size <= sizeof(*ei) + sizeof(*bi)) {
431 WARN_ON(item_size < sizeof(*ei) + sizeof(*bi));
432 return 1;
433 }
434
435 bi = (struct btrfs_tree_block_info *)(ei + 1);
436 *ptr = (unsigned long)(bi + 1);
437 *end = (unsigned long)ei + item_size;
438 return 0;
439 }
440
441 /*
442 * build backref tree for a given tree block. root of the backref tree
443 * corresponds the tree block, leaves of the backref tree correspond
444 * roots of b-trees that reference the tree block.
445 *
446 * the basic idea of this function is check backrefs of a given block
447 * to find upper level blocks that refernece the block, and then check
448 * bakcrefs of these upper level blocks recursively. the recursion stop
449 * when tree root is reached or backrefs for the block is cached.
450 *
451 * NOTE: if we find backrefs for a block are cached, we know backrefs
452 * for all upper level blocks that directly/indirectly reference the
453 * block are also cached.
454 */
455 static struct backref_node *build_backref_tree(struct reloc_control *rc,
456 struct backref_cache *cache,
457 struct btrfs_key *node_key,
458 int level, u64 bytenr)
459 {
460 struct btrfs_path *path1;
461 struct btrfs_path *path2;
462 struct extent_buffer *eb;
463 struct btrfs_root *root;
464 struct backref_node *cur;
465 struct backref_node *upper;
466 struct backref_node *lower;
467 struct backref_node *node = NULL;
468 struct backref_node *exist = NULL;
469 struct backref_edge *edge;
470 struct rb_node *rb_node;
471 struct btrfs_key key;
472 unsigned long end;
473 unsigned long ptr;
474 LIST_HEAD(list);
475 int ret;
476 int err = 0;
477
478 path1 = btrfs_alloc_path();
479 path2 = btrfs_alloc_path();
480 if (!path1 || !path2) {
481 err = -ENOMEM;
482 goto out;
483 }
484
485 node = kmalloc(sizeof(*node), GFP_NOFS);
486 if (!node) {
487 err = -ENOMEM;
488 goto out;
489 }
490
491 backref_node_init(node);
492 node->bytenr = bytenr;
493 node->owner = 0;
494 node->level = level;
495 node->lowest = 1;
496 cur = node;
497 again:
498 end = 0;
499 ptr = 0;
500 key.objectid = cur->bytenr;
501 key.type = BTRFS_EXTENT_ITEM_KEY;
502 key.offset = (u64)-1;
503
504 path1->search_commit_root = 1;
505 path1->skip_locking = 1;
506 ret = btrfs_search_slot(NULL, rc->extent_root, &key, path1,
507 0, 0);
508 if (ret < 0) {
509 err = ret;
510 goto out;
511 }
512 BUG_ON(!ret || !path1->slots[0]);
513
514 path1->slots[0]--;
515
516 WARN_ON(cur->checked);
517 if (!list_empty(&cur->upper)) {
518 /*
519 * the backref was added previously when processsing
520 * backref of type BTRFS_TREE_BLOCK_REF_KEY
521 */
522 BUG_ON(!list_is_singular(&cur->upper));
523 edge = list_entry(cur->upper.next, struct backref_edge,
524 list[LOWER]);
525 BUG_ON(!list_empty(&edge->list[UPPER]));
526 exist = edge->node[UPPER];
527 /*
528 * add the upper level block to pending list if we need
529 * check its backrefs
530 */
531 if (!exist->checked)
532 list_add_tail(&edge->list[UPPER], &list);
533 } else {
534 exist = NULL;
535 }
536
537 while (1) {
538 cond_resched();
539 eb = path1->nodes[0];
540
541 if (ptr >= end) {
542 if (path1->slots[0] >= btrfs_header_nritems(eb)) {
543 ret = btrfs_next_leaf(rc->extent_root, path1);
544 if (ret < 0) {
545 err = ret;
546 goto out;
547 }
548 if (ret > 0)
549 break;
550 eb = path1->nodes[0];
551 }
552
553 btrfs_item_key_to_cpu(eb, &key, path1->slots[0]);
554 if (key.objectid != cur->bytenr) {
555 WARN_ON(exist);
556 break;
557 }
558
559 if (key.type == BTRFS_EXTENT_ITEM_KEY) {
560 ret = find_inline_backref(eb, path1->slots[0],
561 &ptr, &end);
562 if (ret)
563 goto next;
564 }
565 }
566
567 if (ptr < end) {
568 /* update key for inline back ref */
569 struct btrfs_extent_inline_ref *iref;
570 iref = (struct btrfs_extent_inline_ref *)ptr;
571 key.type = btrfs_extent_inline_ref_type(eb, iref);
572 key.offset = btrfs_extent_inline_ref_offset(eb, iref);
573 WARN_ON(key.type != BTRFS_TREE_BLOCK_REF_KEY &&
574 key.type != BTRFS_SHARED_BLOCK_REF_KEY);
575 }
576
577 if (exist &&
578 ((key.type == BTRFS_TREE_BLOCK_REF_KEY &&
579 exist->owner == key.offset) ||
580 (key.type == BTRFS_SHARED_BLOCK_REF_KEY &&
581 exist->bytenr == key.offset))) {
582 exist = NULL;
583 goto next;
584 }
585
586 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
587 if (key.type == BTRFS_SHARED_BLOCK_REF_KEY ||
588 key.type == BTRFS_EXTENT_REF_V0_KEY) {
589 if (key.objectid == key.offset &&
590 key.type == BTRFS_EXTENT_REF_V0_KEY) {
591 struct btrfs_extent_ref_v0 *ref0;
592 ref0 = btrfs_item_ptr(eb, path1->slots[0],
593 struct btrfs_extent_ref_v0);
594 root = find_tree_root(rc, eb, ref0);
595 if (root)
596 cur->root = root;
597 else
598 cur->old_root = 1;
599 break;
600 }
601 #else
602 BUG_ON(key.type == BTRFS_EXTENT_REF_V0_KEY);
603 if (key.type == BTRFS_SHARED_BLOCK_REF_KEY) {
604 #endif
605 if (key.objectid == key.offset) {
606 /*
607 * only root blocks of reloc trees use
608 * backref of this type.
609 */
610 root = find_reloc_root(rc, cur->bytenr);
611 BUG_ON(!root);
612 cur->root = root;
613 break;
614 }
615
616 edge = kzalloc(sizeof(*edge), GFP_NOFS);
617 if (!edge) {
618 err = -ENOMEM;
619 goto out;
620 }
621 rb_node = tree_search(&cache->rb_root, key.offset);
622 if (!rb_node) {
623 upper = kmalloc(sizeof(*upper), GFP_NOFS);
624 if (!upper) {
625 kfree(edge);
626 err = -ENOMEM;
627 goto out;
628 }
629 backref_node_init(upper);
630 upper->bytenr = key.offset;
631 upper->owner = 0;
632 upper->level = cur->level + 1;
633 /*
634 * backrefs for the upper level block isn't
635 * cached, add the block to pending list
636 */
637 list_add_tail(&edge->list[UPPER], &list);
638 } else {
639 upper = rb_entry(rb_node, struct backref_node,
640 rb_node);
641 INIT_LIST_HEAD(&edge->list[UPPER]);
642 }
643 list_add(&edge->list[LOWER], &cur->upper);
644 edge->node[UPPER] = upper;
645 edge->node[LOWER] = cur;
646
647 goto next;
648 } else if (key.type != BTRFS_TREE_BLOCK_REF_KEY) {
649 goto next;
650 }
651
652 /* key.type == BTRFS_TREE_BLOCK_REF_KEY */
653 root = read_fs_root(rc->extent_root->fs_info, key.offset);
654 if (IS_ERR(root)) {
655 err = PTR_ERR(root);
656 goto out;
657 }
658
659 if (btrfs_root_level(&root->root_item) == cur->level) {
660 /* tree root */
661 BUG_ON(btrfs_root_bytenr(&root->root_item) !=
662 cur->bytenr);
663 cur->root = root;
664 break;
665 }
666
667 level = cur->level + 1;
668
669 /*
670 * searching the tree to find upper level blocks
671 * reference the block.
672 */
673 path2->search_commit_root = 1;
674 path2->skip_locking = 1;
675 path2->lowest_level = level;
676 ret = btrfs_search_slot(NULL, root, node_key, path2, 0, 0);
677 path2->lowest_level = 0;
678 if (ret < 0) {
679 err = ret;
680 goto out;
681 }
682 if (ret > 0 && path2->slots[level] > 0)
683 path2->slots[level]--;
684
685 eb = path2->nodes[level];
686 WARN_ON(btrfs_node_blockptr(eb, path2->slots[level]) !=
687 cur->bytenr);
688
689 lower = cur;
690 for (; level < BTRFS_MAX_LEVEL; level++) {
691 if (!path2->nodes[level]) {
692 BUG_ON(btrfs_root_bytenr(&root->root_item) !=
693 lower->bytenr);
694 lower->root = root;
695 break;
696 }
697
698 edge = kzalloc(sizeof(*edge), GFP_NOFS);
699 if (!edge) {
700 err = -ENOMEM;
701 goto out;
702 }
703
704 eb = path2->nodes[level];
705 rb_node = tree_search(&cache->rb_root, eb->start);
706 if (!rb_node) {
707 upper = kmalloc(sizeof(*upper), GFP_NOFS);
708 if (!upper) {
709 kfree(edge);
710 err = -ENOMEM;
711 goto out;
712 }
713 backref_node_init(upper);
714 upper->bytenr = eb->start;
715 upper->owner = btrfs_header_owner(eb);
716 upper->level = lower->level + 1;
717
718 /*
719 * if we know the block isn't shared
720 * we can void checking its backrefs.
721 */
722 if (btrfs_block_can_be_shared(root, eb))
723 upper->checked = 0;
724 else
725 upper->checked = 1;
726
727 /*
728 * add the block to pending list if we
729 * need check its backrefs. only block
730 * at 'cur->level + 1' is added to the
731 * tail of pending list. this guarantees
732 * we check backrefs from lower level
733 * blocks to upper level blocks.
734 */
735 if (!upper->checked &&
736 level == cur->level + 1) {
737 list_add_tail(&edge->list[UPPER],
738 &list);
739 } else
740 INIT_LIST_HEAD(&edge->list[UPPER]);
741 } else {
742 upper = rb_entry(rb_node, struct backref_node,
743 rb_node);
744 BUG_ON(!upper->checked);
745 INIT_LIST_HEAD(&edge->list[UPPER]);
746 }
747 list_add_tail(&edge->list[LOWER], &lower->upper);
748 edge->node[UPPER] = upper;
749 edge->node[LOWER] = lower;
750
751 if (rb_node)
752 break;
753 lower = upper;
754 upper = NULL;
755 }
756 btrfs_release_path(root, path2);
757 next:
758 if (ptr < end) {
759 ptr += btrfs_extent_inline_ref_size(key.type);
760 if (ptr >= end) {
761 WARN_ON(ptr > end);
762 ptr = 0;
763 end = 0;
764 }
765 }
766 if (ptr >= end)
767 path1->slots[0]++;
768 }
769 btrfs_release_path(rc->extent_root, path1);
770
771 cur->checked = 1;
772 WARN_ON(exist);
773
774 /* the pending list isn't empty, take the first block to process */
775 if (!list_empty(&list)) {
776 edge = list_entry(list.next, struct backref_edge, list[UPPER]);
777 list_del_init(&edge->list[UPPER]);
778 cur = edge->node[UPPER];
779 goto again;
780 }
781
782 /*
783 * everything goes well, connect backref nodes and insert backref nodes
784 * into the cache.
785 */
786 BUG_ON(!node->checked);
787 rb_node = tree_insert(&cache->rb_root, node->bytenr, &node->rb_node);
788 BUG_ON(rb_node);
789
790 list_for_each_entry(edge, &node->upper, list[LOWER])
791 list_add_tail(&edge->list[UPPER], &list);
792
793 while (!list_empty(&list)) {
794 edge = list_entry(list.next, struct backref_edge, list[UPPER]);
795 list_del_init(&edge->list[UPPER]);
796 upper = edge->node[UPPER];
797
798 if (!RB_EMPTY_NODE(&upper->rb_node)) {
799 if (upper->lowest) {
800 list_del_init(&upper->lower);
801 upper->lowest = 0;
802 }
803
804 list_add_tail(&edge->list[UPPER], &upper->lower);
805 continue;
806 }
807
808 BUG_ON(!upper->checked);
809 rb_node = tree_insert(&cache->rb_root, upper->bytenr,
810 &upper->rb_node);
811 BUG_ON(rb_node);
812
813 list_add_tail(&edge->list[UPPER], &upper->lower);
814
815 list_for_each_entry(edge, &upper->upper, list[LOWER])
816 list_add_tail(&edge->list[UPPER], &list);
817 }
818 out:
819 btrfs_free_path(path1);
820 btrfs_free_path(path2);
821 if (err) {
822 INIT_LIST_HEAD(&list);
823 upper = node;
824 while (upper) {
825 if (RB_EMPTY_NODE(&upper->rb_node)) {
826 list_splice_tail(&upper->upper, &list);
827 kfree(upper);
828 }
829
830 if (list_empty(&list))
831 break;
832
833 edge = list_entry(list.next, struct backref_edge,
834 list[LOWER]);
835 upper = edge->node[UPPER];
836 kfree(edge);
837 }
838 return ERR_PTR(err);
839 }
840 return node;
841 }
842
843 /*
844 * helper to add 'address of tree root -> reloc tree' mapping
845 */
846 static int __add_reloc_root(struct btrfs_root *root)
847 {
848 struct rb_node *rb_node;
849 struct mapping_node *node;
850 struct reloc_control *rc = root->fs_info->reloc_ctl;
851
852 node = kmalloc(sizeof(*node), GFP_NOFS);
853 BUG_ON(!node);
854
855 node->bytenr = root->node->start;
856 node->data = root;
857
858 spin_lock(&rc->reloc_root_tree.lock);
859 rb_node = tree_insert(&rc->reloc_root_tree.rb_root,
860 node->bytenr, &node->rb_node);
861 spin_unlock(&rc->reloc_root_tree.lock);
862 BUG_ON(rb_node);
863
864 list_add_tail(&root->root_list, &rc->reloc_roots);
865 return 0;
866 }
867
868 /*
869 * helper to update/delete the 'address of tree root -> reloc tree'
870 * mapping
871 */
872 static int __update_reloc_root(struct btrfs_root *root, int del)
873 {
874 struct rb_node *rb_node;
875 struct mapping_node *node = NULL;
876 struct reloc_control *rc = root->fs_info->reloc_ctl;
877
878 spin_lock(&rc->reloc_root_tree.lock);
879 rb_node = tree_search(&rc->reloc_root_tree.rb_root,
880 root->commit_root->start);
881 if (rb_node) {
882 node = rb_entry(rb_node, struct mapping_node, rb_node);
883 rb_erase(&node->rb_node, &rc->reloc_root_tree.rb_root);
884 }
885 spin_unlock(&rc->reloc_root_tree.lock);
886
887 BUG_ON((struct btrfs_root *)node->data != root);
888
889 if (!del) {
890 spin_lock(&rc->reloc_root_tree.lock);
891 node->bytenr = root->node->start;
892 rb_node = tree_insert(&rc->reloc_root_tree.rb_root,
893 node->bytenr, &node->rb_node);
894 spin_unlock(&rc->reloc_root_tree.lock);
895 BUG_ON(rb_node);
896 } else {
897 list_del_init(&root->root_list);
898 kfree(node);
899 }
900 return 0;
901 }
902
903 /*
904 * create reloc tree for a given fs tree. reloc tree is just a
905 * snapshot of the fs tree with special root objectid.
906 */
907 int btrfs_init_reloc_root(struct btrfs_trans_handle *trans,
908 struct btrfs_root *root)
909 {
910 struct btrfs_root *reloc_root;
911 struct extent_buffer *eb;
912 struct btrfs_root_item *root_item;
913 struct btrfs_key root_key;
914 int ret;
915
916 if (root->reloc_root) {
917 reloc_root = root->reloc_root;
918 reloc_root->last_trans = trans->transid;
919 return 0;
920 }
921
922 if (!root->fs_info->reloc_ctl ||
923 !root->fs_info->reloc_ctl->create_reloc_root ||
924 root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID)
925 return 0;
926
927 root_item = kmalloc(sizeof(*root_item), GFP_NOFS);
928 BUG_ON(!root_item);
929
930 root_key.objectid = BTRFS_TREE_RELOC_OBJECTID;
931 root_key.type = BTRFS_ROOT_ITEM_KEY;
932 root_key.offset = root->root_key.objectid;
933
934 ret = btrfs_copy_root(trans, root, root->commit_root, &eb,
935 BTRFS_TREE_RELOC_OBJECTID);
936 BUG_ON(ret);
937
938 btrfs_set_root_last_snapshot(&root->root_item, trans->transid - 1);
939 memcpy(root_item, &root->root_item, sizeof(*root_item));
940 btrfs_set_root_refs(root_item, 1);
941 btrfs_set_root_bytenr(root_item, eb->start);
942 btrfs_set_root_level(root_item, btrfs_header_level(eb));
943 btrfs_set_root_generation(root_item, trans->transid);
944 memset(&root_item->drop_progress, 0, sizeof(struct btrfs_disk_key));
945 root_item->drop_level = 0;
946
947 btrfs_tree_unlock(eb);
948 free_extent_buffer(eb);
949
950 ret = btrfs_insert_root(trans, root->fs_info->tree_root,
951 &root_key, root_item);
952 BUG_ON(ret);
953 kfree(root_item);
954
955 reloc_root = btrfs_read_fs_root_no_radix(root->fs_info->tree_root,
956 &root_key);
957 BUG_ON(IS_ERR(reloc_root));
958 reloc_root->last_trans = trans->transid;
959
960 __add_reloc_root(reloc_root);
961 root->reloc_root = reloc_root;
962 return 0;
963 }
964
965 /*
966 * update root item of reloc tree
967 */
968 int btrfs_update_reloc_root(struct btrfs_trans_handle *trans,
969 struct btrfs_root *root)
970 {
971 struct btrfs_root *reloc_root;
972 struct btrfs_root_item *root_item;
973 int del = 0;
974 int ret;
975
976 if (!root->reloc_root)
977 return 0;
978
979 reloc_root = root->reloc_root;
980 root_item = &reloc_root->root_item;
981
982 if (btrfs_root_refs(root_item) == 0) {
983 root->reloc_root = NULL;
984 del = 1;
985 }
986
987 __update_reloc_root(reloc_root, del);
988
989 if (reloc_root->commit_root != reloc_root->node) {
990 btrfs_set_root_node(root_item, reloc_root->node);
991 free_extent_buffer(reloc_root->commit_root);
992 reloc_root->commit_root = btrfs_root_node(reloc_root);
993 }
994
995 ret = btrfs_update_root(trans, root->fs_info->tree_root,
996 &reloc_root->root_key, root_item);
997 BUG_ON(ret);
998 return 0;
999 }
1000
1001 /*
1002 * helper to find first cached inode with inode number >= objectid
1003 * in a subvolume
1004 */
1005 static struct inode *find_next_inode(struct btrfs_root *root, u64 objectid)
1006 {
1007 struct rb_node *node;
1008 struct rb_node *prev;
1009 struct btrfs_inode *entry;
1010 struct inode *inode;
1011
1012 spin_lock(&root->inode_lock);
1013 again:
1014 node = root->inode_tree.rb_node;
1015 prev = NULL;
1016 while (node) {
1017 prev = node;
1018 entry = rb_entry(node, struct btrfs_inode, rb_node);
1019
1020 if (objectid < entry->vfs_inode.i_ino)
1021 node = node->rb_left;
1022 else if (objectid > entry->vfs_inode.i_ino)
1023 node = node->rb_right;
1024 else
1025 break;
1026 }
1027 if (!node) {
1028 while (prev) {
1029 entry = rb_entry(prev, struct btrfs_inode, rb_node);
1030 if (objectid <= entry->vfs_inode.i_ino) {
1031 node = prev;
1032 break;
1033 }
1034 prev = rb_next(prev);
1035 }
1036 }
1037 while (node) {
1038 entry = rb_entry(node, struct btrfs_inode, rb_node);
1039 inode = igrab(&entry->vfs_inode);
1040 if (inode) {
1041 spin_unlock(&root->inode_lock);
1042 return inode;
1043 }
1044
1045 objectid = entry->vfs_inode.i_ino + 1;
1046 if (cond_resched_lock(&root->inode_lock))
1047 goto again;
1048
1049 node = rb_next(node);
1050 }
1051 spin_unlock(&root->inode_lock);
1052 return NULL;
1053 }
1054
1055 static int in_block_group(u64 bytenr,
1056 struct btrfs_block_group_cache *block_group)
1057 {
1058 if (bytenr >= block_group->key.objectid &&
1059 bytenr < block_group->key.objectid + block_group->key.offset)
1060 return 1;
1061 return 0;
1062 }
1063
1064 /*
1065 * get new location of data
1066 */
1067 static int get_new_location(struct inode *reloc_inode, u64 *new_bytenr,
1068 u64 bytenr, u64 num_bytes)
1069 {
1070 struct btrfs_root *root = BTRFS_I(reloc_inode)->root;
1071 struct btrfs_path *path;
1072 struct btrfs_file_extent_item *fi;
1073 struct extent_buffer *leaf;
1074 int ret;
1075
1076 path = btrfs_alloc_path();
1077 if (!path)
1078 return -ENOMEM;
1079
1080 bytenr -= BTRFS_I(reloc_inode)->index_cnt;
1081 ret = btrfs_lookup_file_extent(NULL, root, path, reloc_inode->i_ino,
1082 bytenr, 0);
1083 if (ret < 0)
1084 goto out;
1085 if (ret > 0) {
1086 ret = -ENOENT;
1087 goto out;
1088 }
1089
1090 leaf = path->nodes[0];
1091 fi = btrfs_item_ptr(leaf, path->slots[0],
1092 struct btrfs_file_extent_item);
1093
1094 BUG_ON(btrfs_file_extent_offset(leaf, fi) ||
1095 btrfs_file_extent_compression(leaf, fi) ||
1096 btrfs_file_extent_encryption(leaf, fi) ||
1097 btrfs_file_extent_other_encoding(leaf, fi));
1098
1099 if (num_bytes != btrfs_file_extent_disk_num_bytes(leaf, fi)) {
1100 ret = 1;
1101 goto out;
1102 }
1103
1104 if (new_bytenr)
1105 *new_bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
1106 ret = 0;
1107 out:
1108 btrfs_free_path(path);
1109 return ret;
1110 }
1111
1112 /*
1113 * update file extent items in the tree leaf to point to
1114 * the new locations.
1115 */
1116 static int replace_file_extents(struct btrfs_trans_handle *trans,
1117 struct reloc_control *rc,
1118 struct btrfs_root *root,
1119 struct extent_buffer *leaf,
1120 struct list_head *inode_list)
1121 {
1122 struct btrfs_key key;
1123 struct btrfs_file_extent_item *fi;
1124 struct inode *inode = NULL;
1125 struct inodevec *ivec = NULL;
1126 u64 parent;
1127 u64 bytenr;
1128 u64 new_bytenr;
1129 u64 num_bytes;
1130 u64 end;
1131 u32 nritems;
1132 u32 i;
1133 int ret;
1134 int first = 1;
1135 int dirty = 0;
1136
1137 if (rc->stage != UPDATE_DATA_PTRS)
1138 return 0;
1139
1140 /* reloc trees always use full backref */
1141 if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID)
1142 parent = leaf->start;
1143 else
1144 parent = 0;
1145
1146 nritems = btrfs_header_nritems(leaf);
1147 for (i = 0; i < nritems; i++) {
1148 cond_resched();
1149 btrfs_item_key_to_cpu(leaf, &key, i);
1150 if (key.type != BTRFS_EXTENT_DATA_KEY)
1151 continue;
1152 fi = btrfs_item_ptr(leaf, i, struct btrfs_file_extent_item);
1153 if (btrfs_file_extent_type(leaf, fi) ==
1154 BTRFS_FILE_EXTENT_INLINE)
1155 continue;
1156 bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
1157 num_bytes = btrfs_file_extent_disk_num_bytes(leaf, fi);
1158 if (bytenr == 0)
1159 continue;
1160 if (!in_block_group(bytenr, rc->block_group))
1161 continue;
1162
1163 /*
1164 * if we are modifying block in fs tree, wait for readpage
1165 * to complete and drop the extent cache
1166 */
1167 if (root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID) {
1168 if (!ivec || ivec->nr == INODEVEC_SIZE) {
1169 ivec = kmalloc(sizeof(*ivec), GFP_NOFS);
1170 BUG_ON(!ivec);
1171 ivec->nr = 0;
1172 list_add_tail(&ivec->list, inode_list);
1173 }
1174 if (first) {
1175 inode = find_next_inode(root, key.objectid);
1176 if (inode)
1177 ivec->inode[ivec->nr++] = inode;
1178 first = 0;
1179 } else if (inode && inode->i_ino < key.objectid) {
1180 inode = find_next_inode(root, key.objectid);
1181 if (inode)
1182 ivec->inode[ivec->nr++] = inode;
1183 }
1184 if (inode && inode->i_ino == key.objectid) {
1185 end = key.offset +
1186 btrfs_file_extent_num_bytes(leaf, fi);
1187 WARN_ON(!IS_ALIGNED(key.offset,
1188 root->sectorsize));
1189 WARN_ON(!IS_ALIGNED(end, root->sectorsize));
1190 end--;
1191 ret = try_lock_extent(&BTRFS_I(inode)->io_tree,
1192 key.offset, end,
1193 GFP_NOFS);
1194 if (!ret)
1195 continue;
1196
1197 btrfs_drop_extent_cache(inode, key.offset, end,
1198 1);
1199 unlock_extent(&BTRFS_I(inode)->io_tree,
1200 key.offset, end, GFP_NOFS);
1201 }
1202 }
1203
1204 ret = get_new_location(rc->data_inode, &new_bytenr,
1205 bytenr, num_bytes);
1206 if (ret > 0)
1207 continue;
1208 BUG_ON(ret < 0);
1209
1210 btrfs_set_file_extent_disk_bytenr(leaf, fi, new_bytenr);
1211 dirty = 1;
1212
1213 key.offset -= btrfs_file_extent_offset(leaf, fi);
1214 ret = btrfs_inc_extent_ref(trans, root, new_bytenr,
1215 num_bytes, parent,
1216 btrfs_header_owner(leaf),
1217 key.objectid, key.offset);
1218 BUG_ON(ret);
1219
1220 ret = btrfs_free_extent(trans, root, bytenr, num_bytes,
1221 parent, btrfs_header_owner(leaf),
1222 key.objectid, key.offset);
1223 BUG_ON(ret);
1224 }
1225 if (dirty)
1226 btrfs_mark_buffer_dirty(leaf);
1227 return 0;
1228 }
1229
1230 static noinline_for_stack
1231 int memcmp_node_keys(struct extent_buffer *eb, int slot,
1232 struct btrfs_path *path, int level)
1233 {
1234 struct btrfs_disk_key key1;
1235 struct btrfs_disk_key key2;
1236 btrfs_node_key(eb, &key1, slot);
1237 btrfs_node_key(path->nodes[level], &key2, path->slots[level]);
1238 return memcmp(&key1, &key2, sizeof(key1));
1239 }
1240
1241 /*
1242 * try to replace tree blocks in fs tree with the new blocks
1243 * in reloc tree. tree blocks haven't been modified since the
1244 * reloc tree was create can be replaced.
1245 *
1246 * if a block was replaced, level of the block + 1 is returned.
1247 * if no block got replaced, 0 is returned. if there are other
1248 * errors, a negative error number is returned.
1249 */
1250 static int replace_path(struct btrfs_trans_handle *trans,
1251 struct btrfs_root *dest, struct btrfs_root *src,
1252 struct btrfs_path *path, struct btrfs_key *next_key,
1253 struct extent_buffer **leaf,
1254 int lowest_level, int max_level)
1255 {
1256 struct extent_buffer *eb;
1257 struct extent_buffer *parent;
1258 struct btrfs_key key;
1259 u64 old_bytenr;
1260 u64 new_bytenr;
1261 u64 old_ptr_gen;
1262 u64 new_ptr_gen;
1263 u64 last_snapshot;
1264 u32 blocksize;
1265 int level;
1266 int ret;
1267 int slot;
1268
1269 BUG_ON(src->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID);
1270 BUG_ON(dest->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID);
1271 BUG_ON(lowest_level > 1 && leaf);
1272
1273 last_snapshot = btrfs_root_last_snapshot(&src->root_item);
1274
1275 slot = path->slots[lowest_level];
1276 btrfs_node_key_to_cpu(path->nodes[lowest_level], &key, slot);
1277
1278 eb = btrfs_lock_root_node(dest);
1279 btrfs_set_lock_blocking(eb);
1280 level = btrfs_header_level(eb);
1281
1282 if (level < lowest_level) {
1283 btrfs_tree_unlock(eb);
1284 free_extent_buffer(eb);
1285 return 0;
1286 }
1287
1288 ret = btrfs_cow_block(trans, dest, eb, NULL, 0, &eb);
1289 BUG_ON(ret);
1290 btrfs_set_lock_blocking(eb);
1291
1292 if (next_key) {
1293 next_key->objectid = (u64)-1;
1294 next_key->type = (u8)-1;
1295 next_key->offset = (u64)-1;
1296 }
1297
1298 parent = eb;
1299 while (1) {
1300 level = btrfs_header_level(parent);
1301 BUG_ON(level < lowest_level);
1302
1303 ret = btrfs_bin_search(parent, &key, level, &slot);
1304 if (ret && slot > 0)
1305 slot--;
1306
1307 if (next_key && slot + 1 < btrfs_header_nritems(parent))
1308 btrfs_node_key_to_cpu(parent, next_key, slot + 1);
1309
1310 old_bytenr = btrfs_node_blockptr(parent, slot);
1311 blocksize = btrfs_level_size(dest, level - 1);
1312 old_ptr_gen = btrfs_node_ptr_generation(parent, slot);
1313
1314 if (level <= max_level) {
1315 eb = path->nodes[level];
1316 new_bytenr = btrfs_node_blockptr(eb,
1317 path->slots[level]);
1318 new_ptr_gen = btrfs_node_ptr_generation(eb,
1319 path->slots[level]);
1320 } else {
1321 new_bytenr = 0;
1322 new_ptr_gen = 0;
1323 }
1324
1325 if (new_bytenr > 0 && new_bytenr == old_bytenr) {
1326 WARN_ON(1);
1327 ret = level;
1328 break;
1329 }
1330
1331 if (new_bytenr == 0 || old_ptr_gen > last_snapshot ||
1332 memcmp_node_keys(parent, slot, path, level)) {
1333 if (level <= lowest_level && !leaf) {
1334 ret = 0;
1335 break;
1336 }
1337
1338 eb = read_tree_block(dest, old_bytenr, blocksize,
1339 old_ptr_gen);
1340 btrfs_tree_lock(eb);
1341 ret = btrfs_cow_block(trans, dest, eb, parent,
1342 slot, &eb);
1343 BUG_ON(ret);
1344 btrfs_set_lock_blocking(eb);
1345
1346 if (level <= lowest_level) {
1347 *leaf = eb;
1348 ret = 0;
1349 break;
1350 }
1351
1352 btrfs_tree_unlock(parent);
1353 free_extent_buffer(parent);
1354
1355 parent = eb;
1356 continue;
1357 }
1358
1359 btrfs_node_key_to_cpu(path->nodes[level], &key,
1360 path->slots[level]);
1361 btrfs_release_path(src, path);
1362
1363 path->lowest_level = level;
1364 ret = btrfs_search_slot(trans, src, &key, path, 0, 1);
1365 path->lowest_level = 0;
1366 BUG_ON(ret);
1367
1368 /*
1369 * swap blocks in fs tree and reloc tree.
1370 */
1371 btrfs_set_node_blockptr(parent, slot, new_bytenr);
1372 btrfs_set_node_ptr_generation(parent, slot, new_ptr_gen);
1373 btrfs_mark_buffer_dirty(parent);
1374
1375 btrfs_set_node_blockptr(path->nodes[level],
1376 path->slots[level], old_bytenr);
1377 btrfs_set_node_ptr_generation(path->nodes[level],
1378 path->slots[level], old_ptr_gen);
1379 btrfs_mark_buffer_dirty(path->nodes[level]);
1380
1381 ret = btrfs_inc_extent_ref(trans, src, old_bytenr, blocksize,
1382 path->nodes[level]->start,
1383 src->root_key.objectid, level - 1, 0);
1384 BUG_ON(ret);
1385 ret = btrfs_inc_extent_ref(trans, dest, new_bytenr, blocksize,
1386 0, dest->root_key.objectid, level - 1,
1387 0);
1388 BUG_ON(ret);
1389
1390 ret = btrfs_free_extent(trans, src, new_bytenr, blocksize,
1391 path->nodes[level]->start,
1392 src->root_key.objectid, level - 1, 0);
1393 BUG_ON(ret);
1394
1395 ret = btrfs_free_extent(trans, dest, old_bytenr, blocksize,
1396 0, dest->root_key.objectid, level - 1,
1397 0);
1398 BUG_ON(ret);
1399
1400 btrfs_unlock_up_safe(path, 0);
1401
1402 ret = level;
1403 break;
1404 }
1405 btrfs_tree_unlock(parent);
1406 free_extent_buffer(parent);
1407 return ret;
1408 }
1409
1410 /*
1411 * helper to find next relocated block in reloc tree
1412 */
1413 static noinline_for_stack
1414 int walk_up_reloc_tree(struct btrfs_root *root, struct btrfs_path *path,
1415 int *level)
1416 {
1417 struct extent_buffer *eb;
1418 int i;
1419 u64 last_snapshot;
1420 u32 nritems;
1421
1422 last_snapshot = btrfs_root_last_snapshot(&root->root_item);
1423
1424 for (i = 0; i < *level; i++) {
1425 free_extent_buffer(path->nodes[i]);
1426 path->nodes[i] = NULL;
1427 }
1428
1429 for (i = *level; i < BTRFS_MAX_LEVEL && path->nodes[i]; i++) {
1430 eb = path->nodes[i];
1431 nritems = btrfs_header_nritems(eb);
1432 while (path->slots[i] + 1 < nritems) {
1433 path->slots[i]++;
1434 if (btrfs_node_ptr_generation(eb, path->slots[i]) <=
1435 last_snapshot)
1436 continue;
1437
1438 *level = i;
1439 return 0;
1440 }
1441 free_extent_buffer(path->nodes[i]);
1442 path->nodes[i] = NULL;
1443 }
1444 return 1;
1445 }
1446
1447 /*
1448 * walk down reloc tree to find relocated block of lowest level
1449 */
1450 static noinline_for_stack
1451 int walk_down_reloc_tree(struct btrfs_root *root, struct btrfs_path *path,
1452 int *level)
1453 {
1454 struct extent_buffer *eb = NULL;
1455 int i;
1456 u64 bytenr;
1457 u64 ptr_gen = 0;
1458 u64 last_snapshot;
1459 u32 blocksize;
1460 u32 nritems;
1461
1462 last_snapshot = btrfs_root_last_snapshot(&root->root_item);
1463
1464 for (i = *level; i > 0; i--) {
1465 eb = path->nodes[i];
1466 nritems = btrfs_header_nritems(eb);
1467 while (path->slots[i] < nritems) {
1468 ptr_gen = btrfs_node_ptr_generation(eb, path->slots[i]);
1469 if (ptr_gen > last_snapshot)
1470 break;
1471 path->slots[i]++;
1472 }
1473 if (path->slots[i] >= nritems) {
1474 if (i == *level)
1475 break;
1476 *level = i + 1;
1477 return 0;
1478 }
1479 if (i == 1) {
1480 *level = i;
1481 return 0;
1482 }
1483
1484 bytenr = btrfs_node_blockptr(eb, path->slots[i]);
1485 blocksize = btrfs_level_size(root, i - 1);
1486 eb = read_tree_block(root, bytenr, blocksize, ptr_gen);
1487 BUG_ON(btrfs_header_level(eb) != i - 1);
1488 path->nodes[i - 1] = eb;
1489 path->slots[i - 1] = 0;
1490 }
1491 return 1;
1492 }
1493
1494 /*
1495 * invalidate extent cache for file extents whose key in range of
1496 * [min_key, max_key)
1497 */
1498 static int invalidate_extent_cache(struct btrfs_root *root,
1499 struct btrfs_key *min_key,
1500 struct btrfs_key *max_key)
1501 {
1502 struct inode *inode = NULL;
1503 u64 objectid;
1504 u64 start, end;
1505
1506 objectid = min_key->objectid;
1507 while (1) {
1508 cond_resched();
1509 iput(inode);
1510
1511 if (objectid > max_key->objectid)
1512 break;
1513
1514 inode = find_next_inode(root, objectid);
1515 if (!inode)
1516 break;
1517
1518 if (inode->i_ino > max_key->objectid) {
1519 iput(inode);
1520 break;
1521 }
1522
1523 objectid = inode->i_ino + 1;
1524 if (!S_ISREG(inode->i_mode))
1525 continue;
1526
1527 if (unlikely(min_key->objectid == inode->i_ino)) {
1528 if (min_key->type > BTRFS_EXTENT_DATA_KEY)
1529 continue;
1530 if (min_key->type < BTRFS_EXTENT_DATA_KEY)
1531 start = 0;
1532 else {
1533 start = min_key->offset;
1534 WARN_ON(!IS_ALIGNED(start, root->sectorsize));
1535 }
1536 } else {
1537 start = 0;
1538 }
1539
1540 if (unlikely(max_key->objectid == inode->i_ino)) {
1541 if (max_key->type < BTRFS_EXTENT_DATA_KEY)
1542 continue;
1543 if (max_key->type > BTRFS_EXTENT_DATA_KEY) {
1544 end = (u64)-1;
1545 } else {
1546 if (max_key->offset == 0)
1547 continue;
1548 end = max_key->offset;
1549 WARN_ON(!IS_ALIGNED(end, root->sectorsize));
1550 end--;
1551 }
1552 } else {
1553 end = (u64)-1;
1554 }
1555
1556 /* the lock_extent waits for readpage to complete */
1557 lock_extent(&BTRFS_I(inode)->io_tree, start, end, GFP_NOFS);
1558 btrfs_drop_extent_cache(inode, start, end, 1);
1559 unlock_extent(&BTRFS_I(inode)->io_tree, start, end, GFP_NOFS);
1560 }
1561 return 0;
1562 }
1563
1564 static int find_next_key(struct btrfs_path *path, int level,
1565 struct btrfs_key *key)
1566
1567 {
1568 while (level < BTRFS_MAX_LEVEL) {
1569 if (!path->nodes[level])
1570 break;
1571 if (path->slots[level] + 1 <
1572 btrfs_header_nritems(path->nodes[level])) {
1573 btrfs_node_key_to_cpu(path->nodes[level], key,
1574 path->slots[level] + 1);
1575 return 0;
1576 }
1577 level++;
1578 }
1579 return 1;
1580 }
1581
1582 /*
1583 * merge the relocated tree blocks in reloc tree with corresponding
1584 * fs tree.
1585 */
1586 static noinline_for_stack int merge_reloc_root(struct reloc_control *rc,
1587 struct btrfs_root *root)
1588 {
1589 LIST_HEAD(inode_list);
1590 struct btrfs_key key;
1591 struct btrfs_key next_key;
1592 struct btrfs_trans_handle *trans;
1593 struct btrfs_root *reloc_root;
1594 struct btrfs_root_item *root_item;
1595 struct btrfs_path *path;
1596 struct extent_buffer *leaf = NULL;
1597 unsigned long nr;
1598 int level;
1599 int max_level;
1600 int replaced = 0;
1601 int ret;
1602 int err = 0;
1603
1604 path = btrfs_alloc_path();
1605 if (!path)
1606 return -ENOMEM;
1607
1608 reloc_root = root->reloc_root;
1609 root_item = &reloc_root->root_item;
1610
1611 if (btrfs_disk_key_objectid(&root_item->drop_progress) == 0) {
1612 level = btrfs_root_level(root_item);
1613 extent_buffer_get(reloc_root->node);
1614 path->nodes[level] = reloc_root->node;
1615 path->slots[level] = 0;
1616 } else {
1617 btrfs_disk_key_to_cpu(&key, &root_item->drop_progress);
1618
1619 level = root_item->drop_level;
1620 BUG_ON(level == 0);
1621 path->lowest_level = level;
1622 ret = btrfs_search_slot(NULL, reloc_root, &key, path, 0, 0);
1623 path->lowest_level = 0;
1624 if (ret < 0) {
1625 btrfs_free_path(path);
1626 return ret;
1627 }
1628
1629 btrfs_node_key_to_cpu(path->nodes[level], &next_key,
1630 path->slots[level]);
1631 WARN_ON(memcmp(&key, &next_key, sizeof(key)));
1632
1633 btrfs_unlock_up_safe(path, 0);
1634 }
1635
1636 if (level == 0 && rc->stage == UPDATE_DATA_PTRS) {
1637 trans = btrfs_start_transaction(root, 1);
1638
1639 leaf = path->nodes[0];
1640 btrfs_item_key_to_cpu(leaf, &key, 0);
1641 btrfs_release_path(reloc_root, path);
1642
1643 ret = btrfs_search_slot(trans, root, &key, path, 0, 1);
1644 if (ret < 0) {
1645 err = ret;
1646 goto out;
1647 }
1648
1649 leaf = path->nodes[0];
1650 btrfs_unlock_up_safe(path, 1);
1651 ret = replace_file_extents(trans, rc, root, leaf,
1652 &inode_list);
1653 if (ret < 0)
1654 err = ret;
1655 goto out;
1656 }
1657
1658 memset(&next_key, 0, sizeof(next_key));
1659
1660 while (1) {
1661 leaf = NULL;
1662 replaced = 0;
1663 trans = btrfs_start_transaction(root, 1);
1664 max_level = level;
1665
1666 ret = walk_down_reloc_tree(reloc_root, path, &level);
1667 if (ret < 0) {
1668 err = ret;
1669 goto out;
1670 }
1671 if (ret > 0)
1672 break;
1673
1674 if (!find_next_key(path, level, &key) &&
1675 btrfs_comp_cpu_keys(&next_key, &key) >= 0) {
1676 ret = 0;
1677 } else if (level == 1 && rc->stage == UPDATE_DATA_PTRS) {
1678 ret = replace_path(trans, root, reloc_root,
1679 path, &next_key, &leaf,
1680 level, max_level);
1681 } else {
1682 ret = replace_path(trans, root, reloc_root,
1683 path, &next_key, NULL,
1684 level, max_level);
1685 }
1686 if (ret < 0) {
1687 err = ret;
1688 goto out;
1689 }
1690
1691 if (ret > 0) {
1692 level = ret;
1693 btrfs_node_key_to_cpu(path->nodes[level], &key,
1694 path->slots[level]);
1695 replaced = 1;
1696 } else if (leaf) {
1697 /*
1698 * no block got replaced, try replacing file extents
1699 */
1700 btrfs_item_key_to_cpu(leaf, &key, 0);
1701 ret = replace_file_extents(trans, rc, root, leaf,
1702 &inode_list);
1703 btrfs_tree_unlock(leaf);
1704 free_extent_buffer(leaf);
1705 BUG_ON(ret < 0);
1706 }
1707
1708 ret = walk_up_reloc_tree(reloc_root, path, &level);
1709 if (ret > 0)
1710 break;
1711
1712 BUG_ON(level == 0);
1713 /*
1714 * save the merging progress in the drop_progress.
1715 * this is OK since root refs == 1 in this case.
1716 */
1717 btrfs_node_key(path->nodes[level], &root_item->drop_progress,
1718 path->slots[level]);
1719 root_item->drop_level = level;
1720
1721 nr = trans->blocks_used;
1722 btrfs_end_transaction(trans, root);
1723
1724 btrfs_btree_balance_dirty(root, nr);
1725
1726 if (replaced && rc->stage == UPDATE_DATA_PTRS)
1727 invalidate_extent_cache(root, &key, &next_key);
1728 }
1729
1730 /*
1731 * handle the case only one block in the fs tree need to be
1732 * relocated and the block is tree root.
1733 */
1734 leaf = btrfs_lock_root_node(root);
1735 ret = btrfs_cow_block(trans, root, leaf, NULL, 0, &leaf);
1736 btrfs_tree_unlock(leaf);
1737 free_extent_buffer(leaf);
1738 if (ret < 0)
1739 err = ret;
1740 out:
1741 btrfs_free_path(path);
1742
1743 if (err == 0) {
1744 memset(&root_item->drop_progress, 0,
1745 sizeof(root_item->drop_progress));
1746 root_item->drop_level = 0;
1747 btrfs_set_root_refs(root_item, 0);
1748 }
1749
1750 nr = trans->blocks_used;
1751 btrfs_end_transaction(trans, root);
1752
1753 btrfs_btree_balance_dirty(root, nr);
1754
1755 /*
1756 * put inodes while we aren't holding the tree locks
1757 */
1758 while (!list_empty(&inode_list)) {
1759 struct inodevec *ivec;
1760 ivec = list_entry(inode_list.next, struct inodevec, list);
1761 list_del(&ivec->list);
1762 while (ivec->nr > 0) {
1763 ivec->nr--;
1764 iput(ivec->inode[ivec->nr]);
1765 }
1766 kfree(ivec);
1767 }
1768
1769 if (replaced && rc->stage == UPDATE_DATA_PTRS)
1770 invalidate_extent_cache(root, &key, &next_key);
1771
1772 return err;
1773 }
1774
1775 /*
1776 * callback for the work threads.
1777 * this function merges reloc tree with corresponding fs tree,
1778 * and then drops the reloc tree.
1779 */
1780 static void merge_func(struct btrfs_work *work)
1781 {
1782 struct btrfs_trans_handle *trans;
1783 struct btrfs_root *root;
1784 struct btrfs_root *reloc_root;
1785 struct async_merge *async;
1786
1787 async = container_of(work, struct async_merge, work);
1788 reloc_root = async->root;
1789
1790 if (btrfs_root_refs(&reloc_root->root_item) > 0) {
1791 root = read_fs_root(reloc_root->fs_info,
1792 reloc_root->root_key.offset);
1793 BUG_ON(IS_ERR(root));
1794 BUG_ON(root->reloc_root != reloc_root);
1795
1796 merge_reloc_root(async->rc, root);
1797
1798 trans = btrfs_start_transaction(root, 1);
1799 btrfs_update_reloc_root(trans, root);
1800 btrfs_end_transaction(trans, root);
1801 }
1802
1803 btrfs_drop_snapshot(reloc_root, 0);
1804
1805 if (atomic_dec_and_test(async->num_pending))
1806 complete(async->done);
1807
1808 kfree(async);
1809 }
1810
1811 static int merge_reloc_roots(struct reloc_control *rc)
1812 {
1813 struct async_merge *async;
1814 struct btrfs_root *root;
1815 struct completion done;
1816 atomic_t num_pending;
1817
1818 init_completion(&done);
1819 atomic_set(&num_pending, 1);
1820
1821 while (!list_empty(&rc->reloc_roots)) {
1822 root = list_entry(rc->reloc_roots.next,
1823 struct btrfs_root, root_list);
1824 list_del_init(&root->root_list);
1825
1826 async = kmalloc(sizeof(*async), GFP_NOFS);
1827 BUG_ON(!async);
1828 async->work.func = merge_func;
1829 async->work.flags = 0;
1830 async->rc = rc;
1831 async->root = root;
1832 async->done = &done;
1833 async->num_pending = &num_pending;
1834 atomic_inc(&num_pending);
1835 btrfs_queue_worker(&rc->workers, &async->work);
1836 }
1837
1838 if (!atomic_dec_and_test(&num_pending))
1839 wait_for_completion(&done);
1840
1841 BUG_ON(!RB_EMPTY_ROOT(&rc->reloc_root_tree.rb_root));
1842 return 0;
1843 }
1844
1845 static void free_block_list(struct rb_root *blocks)
1846 {
1847 struct tree_block *block;
1848 struct rb_node *rb_node;
1849 while ((rb_node = rb_first(blocks))) {
1850 block = rb_entry(rb_node, struct tree_block, rb_node);
1851 rb_erase(rb_node, blocks);
1852 kfree(block);
1853 }
1854 }
1855
1856 static int record_reloc_root_in_trans(struct btrfs_trans_handle *trans,
1857 struct btrfs_root *reloc_root)
1858 {
1859 struct btrfs_root *root;
1860
1861 if (reloc_root->last_trans == trans->transid)
1862 return 0;
1863
1864 root = read_fs_root(reloc_root->fs_info, reloc_root->root_key.offset);
1865 BUG_ON(IS_ERR(root));
1866 BUG_ON(root->reloc_root != reloc_root);
1867
1868 return btrfs_record_root_in_trans(trans, root);
1869 }
1870
1871 /*
1872 * select one tree from trees that references the block.
1873 * for blocks in refernce counted trees, we preper reloc tree.
1874 * if no reloc tree found and reloc_only is true, NULL is returned.
1875 */
1876 static struct btrfs_root *__select_one_root(struct btrfs_trans_handle *trans,
1877 struct backref_node *node,
1878 struct backref_edge *edges[],
1879 int *nr, int reloc_only)
1880 {
1881 struct backref_node *next;
1882 struct btrfs_root *root;
1883 int index;
1884 int loop = 0;
1885 again:
1886 index = 0;
1887 next = node;
1888 while (1) {
1889 cond_resched();
1890 next = walk_up_backref(next, edges, &index);
1891 root = next->root;
1892 if (!root) {
1893 BUG_ON(!node->old_root);
1894 goto skip;
1895 }
1896
1897 /* no other choice for non-refernce counted tree */
1898 if (!root->ref_cows) {
1899 BUG_ON(reloc_only);
1900 break;
1901 }
1902
1903 if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID) {
1904 record_reloc_root_in_trans(trans, root);
1905 break;
1906 }
1907
1908 if (loop) {
1909 btrfs_record_root_in_trans(trans, root);
1910 break;
1911 }
1912
1913 if (reloc_only || next != node) {
1914 if (!root->reloc_root)
1915 btrfs_record_root_in_trans(trans, root);
1916 root = root->reloc_root;
1917 /*
1918 * if the reloc tree was created in current
1919 * transation, there is no node in backref tree
1920 * corresponds to the root of the reloc tree.
1921 */
1922 if (btrfs_root_last_snapshot(&root->root_item) ==
1923 trans->transid - 1)
1924 break;
1925 }
1926 skip:
1927 root = NULL;
1928 next = walk_down_backref(edges, &index);
1929 if (!next || next->level <= node->level)
1930 break;
1931 }
1932
1933 if (!root && !loop && !reloc_only) {
1934 loop = 1;
1935 goto again;
1936 }
1937
1938 if (root)
1939 *nr = index;
1940 else
1941 *nr = 0;
1942
1943 return root;
1944 }
1945
1946 static noinline_for_stack
1947 struct btrfs_root *select_one_root(struct btrfs_trans_handle *trans,
1948 struct backref_node *node)
1949 {
1950 struct backref_edge *edges[BTRFS_MAX_LEVEL - 1];
1951 int nr;
1952 return __select_one_root(trans, node, edges, &nr, 0);
1953 }
1954
1955 static noinline_for_stack
1956 struct btrfs_root *select_reloc_root(struct btrfs_trans_handle *trans,
1957 struct backref_node *node,
1958 struct backref_edge *edges[], int *nr)
1959 {
1960 return __select_one_root(trans, node, edges, nr, 1);
1961 }
1962
1963 static void grab_path_buffers(struct btrfs_path *path,
1964 struct backref_node *node,
1965 struct backref_edge *edges[], int nr)
1966 {
1967 int i = 0;
1968 while (1) {
1969 drop_node_buffer(node);
1970 node->eb = path->nodes[node->level];
1971 BUG_ON(!node->eb);
1972 if (path->locks[node->level])
1973 node->locked = 1;
1974 path->nodes[node->level] = NULL;
1975 path->locks[node->level] = 0;
1976
1977 if (i >= nr)
1978 break;
1979
1980 edges[i]->blockptr = node->eb->start;
1981 node = edges[i]->node[UPPER];
1982 i++;
1983 }
1984 }
1985
1986 /*
1987 * relocate a block tree, and then update pointers in upper level
1988 * blocks that reference the block to point to the new location.
1989 *
1990 * if called by link_to_upper, the block has already been relocated.
1991 * in that case this function just updates pointers.
1992 */
1993 static int do_relocation(struct btrfs_trans_handle *trans,
1994 struct backref_node *node,
1995 struct btrfs_key *key,
1996 struct btrfs_path *path, int lowest)
1997 {
1998 struct backref_node *upper;
1999 struct backref_edge *edge;
2000 struct backref_edge *edges[BTRFS_MAX_LEVEL - 1];
2001 struct btrfs_root *root;
2002 struct extent_buffer *eb;
2003 u32 blocksize;
2004 u64 bytenr;
2005 u64 generation;
2006 int nr;
2007 int slot;
2008 int ret;
2009 int err = 0;
2010
2011 BUG_ON(lowest && node->eb);
2012
2013 path->lowest_level = node->level + 1;
2014 list_for_each_entry(edge, &node->upper, list[LOWER]) {
2015 cond_resched();
2016 if (node->eb && node->eb->start == edge->blockptr)
2017 continue;
2018
2019 upper = edge->node[UPPER];
2020 root = select_reloc_root(trans, upper, edges, &nr);
2021 if (!root)
2022 continue;
2023
2024 if (upper->eb && !upper->locked)
2025 drop_node_buffer(upper);
2026
2027 if (!upper->eb) {
2028 ret = btrfs_search_slot(trans, root, key, path, 0, 1);
2029 if (ret < 0) {
2030 err = ret;
2031 break;
2032 }
2033 BUG_ON(ret > 0);
2034
2035 slot = path->slots[upper->level];
2036
2037 btrfs_unlock_up_safe(path, upper->level + 1);
2038 grab_path_buffers(path, upper, edges, nr);
2039
2040 btrfs_release_path(NULL, path);
2041 } else {
2042 ret = btrfs_bin_search(upper->eb, key, upper->level,
2043 &slot);
2044 BUG_ON(ret);
2045 }
2046
2047 bytenr = btrfs_node_blockptr(upper->eb, slot);
2048 if (!lowest) {
2049 if (node->eb->start == bytenr) {
2050 btrfs_tree_unlock(upper->eb);
2051 upper->locked = 0;
2052 continue;
2053 }
2054 } else {
2055 BUG_ON(node->bytenr != bytenr);
2056 }
2057
2058 blocksize = btrfs_level_size(root, node->level);
2059 generation = btrfs_node_ptr_generation(upper->eb, slot);
2060 eb = read_tree_block(root, bytenr, blocksize, generation);
2061 btrfs_tree_lock(eb);
2062 btrfs_set_lock_blocking(eb);
2063
2064 if (!node->eb) {
2065 ret = btrfs_cow_block(trans, root, eb, upper->eb,
2066 slot, &eb);
2067 if (ret < 0) {
2068 err = ret;
2069 break;
2070 }
2071 btrfs_set_lock_blocking(eb);
2072 node->eb = eb;
2073 node->locked = 1;
2074 } else {
2075 btrfs_set_node_blockptr(upper->eb, slot,
2076 node->eb->start);
2077 btrfs_set_node_ptr_generation(upper->eb, slot,
2078 trans->transid);
2079 btrfs_mark_buffer_dirty(upper->eb);
2080
2081 ret = btrfs_inc_extent_ref(trans, root,
2082 node->eb->start, blocksize,
2083 upper->eb->start,
2084 btrfs_header_owner(upper->eb),
2085 node->level, 0);
2086 BUG_ON(ret);
2087
2088 ret = btrfs_drop_subtree(trans, root, eb, upper->eb);
2089 BUG_ON(ret);
2090 }
2091 if (!lowest) {
2092 btrfs_tree_unlock(upper->eb);
2093 upper->locked = 0;
2094 }
2095 }
2096 path->lowest_level = 0;
2097 return err;
2098 }
2099
2100 static int link_to_upper(struct btrfs_trans_handle *trans,
2101 struct backref_node *node,
2102 struct btrfs_path *path)
2103 {
2104 struct btrfs_key key;
2105 if (!node->eb || list_empty(&node->upper))
2106 return 0;
2107
2108 btrfs_node_key_to_cpu(node->eb, &key, 0);
2109 return do_relocation(trans, node, &key, path, 0);
2110 }
2111
2112 static int finish_pending_nodes(struct btrfs_trans_handle *trans,
2113 struct backref_cache *cache,
2114 struct btrfs_path *path)
2115 {
2116 struct backref_node *node;
2117 int level;
2118 int ret;
2119 int err = 0;
2120
2121 for (level = 0; level < BTRFS_MAX_LEVEL; level++) {
2122 while (!list_empty(&cache->pending[level])) {
2123 node = list_entry(cache->pending[level].next,
2124 struct backref_node, lower);
2125 BUG_ON(node->level != level);
2126
2127 ret = link_to_upper(trans, node, path);
2128 if (ret < 0)
2129 err = ret;
2130 /*
2131 * this remove the node from the pending list and
2132 * may add some other nodes to the level + 1
2133 * pending list
2134 */
2135 remove_backref_node(cache, node);
2136 }
2137 }
2138 BUG_ON(!RB_EMPTY_ROOT(&cache->rb_root));
2139 return err;
2140 }
2141
2142 static void mark_block_processed(struct reloc_control *rc,
2143 struct backref_node *node)
2144 {
2145 u32 blocksize;
2146 if (node->level == 0 ||
2147 in_block_group(node->bytenr, rc->block_group)) {
2148 blocksize = btrfs_level_size(rc->extent_root, node->level);
2149 set_extent_bits(&rc->processed_blocks, node->bytenr,
2150 node->bytenr + blocksize - 1, EXTENT_DIRTY,
2151 GFP_NOFS);
2152 }
2153 node->processed = 1;
2154 }
2155
2156 /*
2157 * mark a block and all blocks directly/indirectly reference the block
2158 * as processed.
2159 */
2160 static void update_processed_blocks(struct reloc_control *rc,
2161 struct backref_node *node)
2162 {
2163 struct backref_node *next = node;
2164 struct backref_edge *edge;
2165 struct backref_edge *edges[BTRFS_MAX_LEVEL - 1];
2166 int index = 0;
2167
2168 while (next) {
2169 cond_resched();
2170 while (1) {
2171 if (next->processed)
2172 break;
2173
2174 mark_block_processed(rc, next);
2175
2176 if (list_empty(&next->upper))
2177 break;
2178
2179 edge = list_entry(next->upper.next,
2180 struct backref_edge, list[LOWER]);
2181 edges[index++] = edge;
2182 next = edge->node[UPPER];
2183 }
2184 next = walk_down_backref(edges, &index);
2185 }
2186 }
2187
2188 static int tree_block_processed(u64 bytenr, u32 blocksize,
2189 struct reloc_control *rc)
2190 {
2191 if (test_range_bit(&rc->processed_blocks, bytenr,
2192 bytenr + blocksize - 1, EXTENT_DIRTY, 1, NULL))
2193 return 1;
2194 return 0;
2195 }
2196
2197 /*
2198 * check if there are any file extent pointers in the leaf point to
2199 * data require processing
2200 */
2201 static int check_file_extents(struct reloc_control *rc,
2202 u64 bytenr, u32 blocksize, u64 ptr_gen)
2203 {
2204 struct btrfs_key found_key;
2205 struct btrfs_file_extent_item *fi;
2206 struct extent_buffer *leaf;
2207 u32 nritems;
2208 int i;
2209 int ret = 0;
2210
2211 leaf = read_tree_block(rc->extent_root, bytenr, blocksize, ptr_gen);
2212
2213 nritems = btrfs_header_nritems(leaf);
2214 for (i = 0; i < nritems; i++) {
2215 cond_resched();
2216 btrfs_item_key_to_cpu(leaf, &found_key, i);
2217 if (found_key.type != BTRFS_EXTENT_DATA_KEY)
2218 continue;
2219 fi = btrfs_item_ptr(leaf, i, struct btrfs_file_extent_item);
2220 if (btrfs_file_extent_type(leaf, fi) ==
2221 BTRFS_FILE_EXTENT_INLINE)
2222 continue;
2223 bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
2224 if (bytenr == 0)
2225 continue;
2226 if (in_block_group(bytenr, rc->block_group)) {
2227 ret = 1;
2228 break;
2229 }
2230 }
2231 free_extent_buffer(leaf);
2232 return ret;
2233 }
2234
2235 /*
2236 * scan child blocks of a given block to find blocks require processing
2237 */
2238 static int add_child_blocks(struct btrfs_trans_handle *trans,
2239 struct reloc_control *rc,
2240 struct backref_node *node,
2241 struct rb_root *blocks)
2242 {
2243 struct tree_block *block;
2244 struct rb_node *rb_node;
2245 u64 bytenr;
2246 u64 ptr_gen;
2247 u32 blocksize;
2248 u32 nritems;
2249 int i;
2250 int err = 0;
2251
2252 nritems = btrfs_header_nritems(node->eb);
2253 blocksize = btrfs_level_size(rc->extent_root, node->level - 1);
2254 for (i = 0; i < nritems; i++) {
2255 cond_resched();
2256 bytenr = btrfs_node_blockptr(node->eb, i);
2257 ptr_gen = btrfs_node_ptr_generation(node->eb, i);
2258 if (ptr_gen == trans->transid)
2259 continue;
2260 if (!in_block_group(bytenr, rc->block_group) &&
2261 (node->level > 1 || rc->stage == MOVE_DATA_EXTENTS))
2262 continue;
2263 if (tree_block_processed(bytenr, blocksize, rc))
2264 continue;
2265
2266 readahead_tree_block(rc->extent_root,
2267 bytenr, blocksize, ptr_gen);
2268 }
2269
2270 for (i = 0; i < nritems; i++) {
2271 cond_resched();
2272 bytenr = btrfs_node_blockptr(node->eb, i);
2273 ptr_gen = btrfs_node_ptr_generation(node->eb, i);
2274 if (ptr_gen == trans->transid)
2275 continue;
2276 if (!in_block_group(bytenr, rc->block_group) &&
2277 (node->level > 1 || rc->stage == MOVE_DATA_EXTENTS))
2278 continue;
2279 if (tree_block_processed(bytenr, blocksize, rc))
2280 continue;
2281 if (!in_block_group(bytenr, rc->block_group) &&
2282 !check_file_extents(rc, bytenr, blocksize, ptr_gen))
2283 continue;
2284
2285 block = kmalloc(sizeof(*block), GFP_NOFS);
2286 if (!block) {
2287 err = -ENOMEM;
2288 break;
2289 }
2290 block->bytenr = bytenr;
2291 btrfs_node_key_to_cpu(node->eb, &block->key, i);
2292 block->level = node->level - 1;
2293 block->key_ready = 1;
2294 rb_node = tree_insert(blocks, block->bytenr, &block->rb_node);
2295 BUG_ON(rb_node);
2296 }
2297 if (err)
2298 free_block_list(blocks);
2299 return err;
2300 }
2301
2302 /*
2303 * find adjacent blocks require processing
2304 */
2305 static noinline_for_stack
2306 int add_adjacent_blocks(struct btrfs_trans_handle *trans,
2307 struct reloc_control *rc,
2308 struct backref_cache *cache,
2309 struct rb_root *blocks, int level,
2310 struct backref_node **upper)
2311 {
2312 struct backref_node *node;
2313 int ret = 0;
2314
2315 WARN_ON(!list_empty(&cache->pending[level]));
2316
2317 if (list_empty(&cache->pending[level + 1]))
2318 return 1;
2319
2320 node = list_entry(cache->pending[level + 1].next,
2321 struct backref_node, lower);
2322 if (node->eb)
2323 ret = add_child_blocks(trans, rc, node, blocks);
2324
2325 *upper = node;
2326 return ret;
2327 }
2328
2329 static int get_tree_block_key(struct reloc_control *rc,
2330 struct tree_block *block)
2331 {
2332 struct extent_buffer *eb;
2333
2334 BUG_ON(block->key_ready);
2335 eb = read_tree_block(rc->extent_root, block->bytenr,
2336 block->key.objectid, block->key.offset);
2337 WARN_ON(btrfs_header_level(eb) != block->level);
2338 if (block->level == 0)
2339 btrfs_item_key_to_cpu(eb, &block->key, 0);
2340 else
2341 btrfs_node_key_to_cpu(eb, &block->key, 0);
2342 free_extent_buffer(eb);
2343 block->key_ready = 1;
2344 return 0;
2345 }
2346
2347 static int reada_tree_block(struct reloc_control *rc,
2348 struct tree_block *block)
2349 {
2350 BUG_ON(block->key_ready);
2351 readahead_tree_block(rc->extent_root, block->bytenr,
2352 block->key.objectid, block->key.offset);
2353 return 0;
2354 }
2355
2356 /*
2357 * helper function to relocate a tree block
2358 */
2359 static int relocate_tree_block(struct btrfs_trans_handle *trans,
2360 struct reloc_control *rc,
2361 struct backref_node *node,
2362 struct btrfs_key *key,
2363 struct btrfs_path *path)
2364 {
2365 struct btrfs_root *root;
2366 int ret;
2367
2368 root = select_one_root(trans, node);
2369 if (unlikely(!root)) {
2370 rc->found_old_snapshot = 1;
2371 update_processed_blocks(rc, node);
2372 return 0;
2373 }
2374
2375 if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID) {
2376 ret = do_relocation(trans, node, key, path, 1);
2377 if (ret < 0)
2378 goto out;
2379 if (node->level == 0 && rc->stage == UPDATE_DATA_PTRS) {
2380 ret = replace_file_extents(trans, rc, root,
2381 node->eb, NULL);
2382 if (ret < 0)
2383 goto out;
2384 }
2385 drop_node_buffer(node);
2386 } else if (!root->ref_cows) {
2387 path->lowest_level = node->level;
2388 ret = btrfs_search_slot(trans, root, key, path, 0, 1);
2389 btrfs_release_path(root, path);
2390 if (ret < 0)
2391 goto out;
2392 } else if (root != node->root) {
2393 WARN_ON(node->level > 0 || rc->stage != UPDATE_DATA_PTRS);
2394 }
2395
2396 update_processed_blocks(rc, node);
2397 ret = 0;
2398 out:
2399 drop_node_buffer(node);
2400 return ret;
2401 }
2402
2403 /*
2404 * relocate a list of blocks
2405 */
2406 static noinline_for_stack
2407 int relocate_tree_blocks(struct btrfs_trans_handle *trans,
2408 struct reloc_control *rc, struct rb_root *blocks)
2409 {
2410 struct backref_cache *cache;
2411 struct backref_node *node;
2412 struct btrfs_path *path;
2413 struct tree_block *block;
2414 struct rb_node *rb_node;
2415 int level = -1;
2416 int ret;
2417 int err = 0;
2418
2419 path = btrfs_alloc_path();
2420 if (!path)
2421 return -ENOMEM;
2422
2423 cache = kmalloc(sizeof(*cache), GFP_NOFS);
2424 if (!cache) {
2425 btrfs_free_path(path);
2426 return -ENOMEM;
2427 }
2428
2429 backref_cache_init(cache);
2430
2431 rb_node = rb_first(blocks);
2432 while (rb_node) {
2433 block = rb_entry(rb_node, struct tree_block, rb_node);
2434 if (level == -1)
2435 level = block->level;
2436 else
2437 BUG_ON(level != block->level);
2438 if (!block->key_ready)
2439 reada_tree_block(rc, block);
2440 rb_node = rb_next(rb_node);
2441 }
2442
2443 rb_node = rb_first(blocks);
2444 while (rb_node) {
2445 block = rb_entry(rb_node, struct tree_block, rb_node);
2446 if (!block->key_ready)
2447 get_tree_block_key(rc, block);
2448 rb_node = rb_next(rb_node);
2449 }
2450
2451 rb_node = rb_first(blocks);
2452 while (rb_node) {
2453 block = rb_entry(rb_node, struct tree_block, rb_node);
2454
2455 node = build_backref_tree(rc, cache, &block->key,
2456 block->level, block->bytenr);
2457 if (IS_ERR(node)) {
2458 err = PTR_ERR(node);
2459 goto out;
2460 }
2461
2462 ret = relocate_tree_block(trans, rc, node, &block->key,
2463 path);
2464 if (ret < 0) {
2465 err = ret;
2466 goto out;
2467 }
2468 remove_backref_node(cache, node);
2469 rb_node = rb_next(rb_node);
2470 }
2471
2472 if (level > 0)
2473 goto out;
2474
2475 free_block_list(blocks);
2476
2477 /*
2478 * now backrefs of some upper level tree blocks have been cached,
2479 * try relocating blocks referenced by these upper level blocks.
2480 */
2481 while (1) {
2482 struct backref_node *upper = NULL;
2483 if (trans->transaction->in_commit ||
2484 trans->transaction->delayed_refs.flushing)
2485 break;
2486
2487 ret = add_adjacent_blocks(trans, rc, cache, blocks, level,
2488 &upper);
2489 if (ret < 0)
2490 err = ret;
2491 if (ret != 0)
2492 break;
2493
2494 rb_node = rb_first(blocks);
2495 while (rb_node) {
2496 block = rb_entry(rb_node, struct tree_block, rb_node);
2497 if (trans->transaction->in_commit ||
2498 trans->transaction->delayed_refs.flushing)
2499 goto out;
2500 BUG_ON(!block->key_ready);
2501 node = build_backref_tree(rc, cache, &block->key,
2502 level, block->bytenr);
2503 if (IS_ERR(node)) {
2504 err = PTR_ERR(node);
2505 goto out;
2506 }
2507
2508 ret = relocate_tree_block(trans, rc, node,
2509 &block->key, path);
2510 if (ret < 0) {
2511 err = ret;
2512 goto out;
2513 }
2514 remove_backref_node(cache, node);
2515 rb_node = rb_next(rb_node);
2516 }
2517 free_block_list(blocks);
2518
2519 if (upper) {
2520 ret = link_to_upper(trans, upper, path);
2521 if (ret < 0) {
2522 err = ret;
2523 break;
2524 }
2525 remove_backref_node(cache, upper);
2526 }
2527 }
2528 out:
2529 free_block_list(blocks);
2530
2531 ret = finish_pending_nodes(trans, cache, path);
2532 if (ret < 0)
2533 err = ret;
2534
2535 kfree(cache);
2536 btrfs_free_path(path);
2537 return err;
2538 }
2539
2540 static noinline_for_stack
2541 int setup_extent_mapping(struct inode *inode, u64 start, u64 end,
2542 u64 block_start)
2543 {
2544 struct btrfs_root *root = BTRFS_I(inode)->root;
2545 struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
2546 struct extent_map *em;
2547 int ret = 0;
2548
2549 em = alloc_extent_map(GFP_NOFS);
2550 if (!em)
2551 return -ENOMEM;
2552
2553 em->start = start;
2554 em->len = end + 1 - start;
2555 em->block_len = em->len;
2556 em->block_start = block_start;
2557 em->bdev = root->fs_info->fs_devices->latest_bdev;
2558 set_bit(EXTENT_FLAG_PINNED, &em->flags);
2559
2560 lock_extent(&BTRFS_I(inode)->io_tree, start, end, GFP_NOFS);
2561 while (1) {
2562 write_lock(&em_tree->lock);
2563 ret = add_extent_mapping(em_tree, em);
2564 write_unlock(&em_tree->lock);
2565 if (ret != -EEXIST) {
2566 free_extent_map(em);
2567 break;
2568 }
2569 btrfs_drop_extent_cache(inode, start, end, 0);
2570 }
2571 unlock_extent(&BTRFS_I(inode)->io_tree, start, end, GFP_NOFS);
2572 return ret;
2573 }
2574
2575 static int relocate_file_extent_cluster(struct inode *inode,
2576 struct file_extent_cluster *cluster)
2577 {
2578 u64 page_start;
2579 u64 page_end;
2580 u64 offset = BTRFS_I(inode)->index_cnt;
2581 unsigned long index;
2582 unsigned long last_index;
2583 unsigned int dirty_page = 0;
2584 struct page *page;
2585 struct file_ra_state *ra;
2586 int nr = 0;
2587 int ret = 0;
2588
2589 if (!cluster->nr)
2590 return 0;
2591
2592 ra = kzalloc(sizeof(*ra), GFP_NOFS);
2593 if (!ra)
2594 return -ENOMEM;
2595
2596 index = (cluster->start - offset) >> PAGE_CACHE_SHIFT;
2597 last_index = (cluster->end - offset) >> PAGE_CACHE_SHIFT;
2598
2599 mutex_lock(&inode->i_mutex);
2600
2601 i_size_write(inode, cluster->end + 1 - offset);
2602 ret = setup_extent_mapping(inode, cluster->start - offset,
2603 cluster->end - offset, cluster->start);
2604 if (ret)
2605 goto out_unlock;
2606
2607 file_ra_state_init(ra, inode->i_mapping);
2608
2609 WARN_ON(cluster->start != cluster->boundary[0]);
2610 while (index <= last_index) {
2611 page = find_lock_page(inode->i_mapping, index);
2612 if (!page) {
2613 page_cache_sync_readahead(inode->i_mapping,
2614 ra, NULL, index,
2615 last_index + 1 - index);
2616 page = grab_cache_page(inode->i_mapping, index);
2617 if (!page) {
2618 ret = -ENOMEM;
2619 goto out_unlock;
2620 }
2621 }
2622
2623 if (PageReadahead(page)) {
2624 page_cache_async_readahead(inode->i_mapping,
2625 ra, NULL, page, index,
2626 last_index + 1 - index);
2627 }
2628
2629 if (!PageUptodate(page)) {
2630 btrfs_readpage(NULL, page);
2631 lock_page(page);
2632 if (!PageUptodate(page)) {
2633 unlock_page(page);
2634 page_cache_release(page);
2635 ret = -EIO;
2636 goto out_unlock;
2637 }
2638 }
2639
2640 page_start = (u64)page->index << PAGE_CACHE_SHIFT;
2641 page_end = page_start + PAGE_CACHE_SIZE - 1;
2642
2643 lock_extent(&BTRFS_I(inode)->io_tree,
2644 page_start, page_end, GFP_NOFS);
2645
2646 set_page_extent_mapped(page);
2647
2648 if (nr < cluster->nr &&
2649 page_start + offset == cluster->boundary[nr]) {
2650 set_extent_bits(&BTRFS_I(inode)->io_tree,
2651 page_start, page_end,
2652 EXTENT_BOUNDARY, GFP_NOFS);
2653 nr++;
2654 }
2655 btrfs_set_extent_delalloc(inode, page_start, page_end);
2656
2657 set_page_dirty(page);
2658 dirty_page++;
2659
2660 unlock_extent(&BTRFS_I(inode)->io_tree,
2661 page_start, page_end, GFP_NOFS);
2662 unlock_page(page);
2663 page_cache_release(page);
2664
2665 index++;
2666 if (nr < cluster->nr &&
2667 page_end + 1 + offset == cluster->boundary[nr]) {
2668 balance_dirty_pages_ratelimited_nr(inode->i_mapping,
2669 dirty_page);
2670 dirty_page = 0;
2671 }
2672 }
2673 if (dirty_page) {
2674 balance_dirty_pages_ratelimited_nr(inode->i_mapping,
2675 dirty_page);
2676 }
2677 WARN_ON(nr != cluster->nr);
2678 out_unlock:
2679 mutex_unlock(&inode->i_mutex);
2680 kfree(ra);
2681 return ret;
2682 }
2683
2684 static noinline_for_stack
2685 int relocate_data_extent(struct inode *inode, struct btrfs_key *extent_key,
2686 struct file_extent_cluster *cluster)
2687 {
2688 int ret;
2689
2690 if (cluster->nr > 0 && extent_key->objectid != cluster->end + 1) {
2691 ret = relocate_file_extent_cluster(inode, cluster);
2692 if (ret)
2693 return ret;
2694 cluster->nr = 0;
2695 }
2696
2697 if (!cluster->nr)
2698 cluster->start = extent_key->objectid;
2699 else
2700 BUG_ON(cluster->nr >= MAX_EXTENTS);
2701 cluster->end = extent_key->objectid + extent_key->offset - 1;
2702 cluster->boundary[cluster->nr] = extent_key->objectid;
2703 cluster->nr++;
2704
2705 if (cluster->nr >= MAX_EXTENTS) {
2706 ret = relocate_file_extent_cluster(inode, cluster);
2707 if (ret)
2708 return ret;
2709 cluster->nr = 0;
2710 }
2711 return 0;
2712 }
2713
2714 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
2715 static int get_ref_objectid_v0(struct reloc_control *rc,
2716 struct btrfs_path *path,
2717 struct btrfs_key *extent_key,
2718 u64 *ref_objectid, int *path_change)
2719 {
2720 struct btrfs_key key;
2721 struct extent_buffer *leaf;
2722 struct btrfs_extent_ref_v0 *ref0;
2723 int ret;
2724 int slot;
2725
2726 leaf = path->nodes[0];
2727 slot = path->slots[0];
2728 while (1) {
2729 if (slot >= btrfs_header_nritems(leaf)) {
2730 ret = btrfs_next_leaf(rc->extent_root, path);
2731 if (ret < 0)
2732 return ret;
2733 BUG_ON(ret > 0);
2734 leaf = path->nodes[0];
2735 slot = path->slots[0];
2736 if (path_change)
2737 *path_change = 1;
2738 }
2739 btrfs_item_key_to_cpu(leaf, &key, slot);
2740 if (key.objectid != extent_key->objectid)
2741 return -ENOENT;
2742
2743 if (key.type != BTRFS_EXTENT_REF_V0_KEY) {
2744 slot++;
2745 continue;
2746 }
2747 ref0 = btrfs_item_ptr(leaf, slot,
2748 struct btrfs_extent_ref_v0);
2749 *ref_objectid = btrfs_ref_objectid_v0(leaf, ref0);
2750 break;
2751 }
2752 return 0;
2753 }
2754 #endif
2755
2756 /*
2757 * helper to add a tree block to the list.
2758 * the major work is getting the generation and level of the block
2759 */
2760 static int add_tree_block(struct reloc_control *rc,
2761 struct btrfs_key *extent_key,
2762 struct btrfs_path *path,
2763 struct rb_root *blocks)
2764 {
2765 struct extent_buffer *eb;
2766 struct btrfs_extent_item *ei;
2767 struct btrfs_tree_block_info *bi;
2768 struct tree_block *block;
2769 struct rb_node *rb_node;
2770 u32 item_size;
2771 int level = -1;
2772 int generation;
2773
2774 eb = path->nodes[0];
2775 item_size = btrfs_item_size_nr(eb, path->slots[0]);
2776
2777 if (item_size >= sizeof(*ei) + sizeof(*bi)) {
2778 ei = btrfs_item_ptr(eb, path->slots[0],
2779 struct btrfs_extent_item);
2780 bi = (struct btrfs_tree_block_info *)(ei + 1);
2781 generation = btrfs_extent_generation(eb, ei);
2782 level = btrfs_tree_block_level(eb, bi);
2783 } else {
2784 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
2785 u64 ref_owner;
2786 int ret;
2787
2788 BUG_ON(item_size != sizeof(struct btrfs_extent_item_v0));
2789 ret = get_ref_objectid_v0(rc, path, extent_key,
2790 &ref_owner, NULL);
2791 BUG_ON(ref_owner >= BTRFS_MAX_LEVEL);
2792 level = (int)ref_owner;
2793 /* FIXME: get real generation */
2794 generation = 0;
2795 #else
2796 BUG();
2797 #endif
2798 }
2799
2800 btrfs_release_path(rc->extent_root, path);
2801
2802 BUG_ON(level == -1);
2803
2804 block = kmalloc(sizeof(*block), GFP_NOFS);
2805 if (!block)
2806 return -ENOMEM;
2807
2808 block->bytenr = extent_key->objectid;
2809 block->key.objectid = extent_key->offset;
2810 block->key.offset = generation;
2811 block->level = level;
2812 block->key_ready = 0;
2813
2814 rb_node = tree_insert(blocks, block->bytenr, &block->rb_node);
2815 BUG_ON(rb_node);
2816
2817 return 0;
2818 }
2819
2820 /*
2821 * helper to add tree blocks for backref of type BTRFS_SHARED_DATA_REF_KEY
2822 */
2823 static int __add_tree_block(struct reloc_control *rc,
2824 u64 bytenr, u32 blocksize,
2825 struct rb_root *blocks)
2826 {
2827 struct btrfs_path *path;
2828 struct btrfs_key key;
2829 int ret;
2830
2831 if (tree_block_processed(bytenr, blocksize, rc))
2832 return 0;
2833
2834 if (tree_search(blocks, bytenr))
2835 return 0;
2836
2837 path = btrfs_alloc_path();
2838 if (!path)
2839 return -ENOMEM;
2840
2841 key.objectid = bytenr;
2842 key.type = BTRFS_EXTENT_ITEM_KEY;
2843 key.offset = blocksize;
2844
2845 path->search_commit_root = 1;
2846 path->skip_locking = 1;
2847 ret = btrfs_search_slot(NULL, rc->extent_root, &key, path, 0, 0);
2848 if (ret < 0)
2849 goto out;
2850 BUG_ON(ret);
2851
2852 btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
2853 ret = add_tree_block(rc, &key, path, blocks);
2854 out:
2855 btrfs_free_path(path);
2856 return ret;
2857 }
2858
2859 /*
2860 * helper to check if the block use full backrefs for pointers in it
2861 */
2862 static int block_use_full_backref(struct reloc_control *rc,
2863 struct extent_buffer *eb)
2864 {
2865 struct btrfs_path *path;
2866 struct btrfs_extent_item *ei;
2867 struct btrfs_key key;
2868 u64 flags;
2869 int ret;
2870
2871 if (btrfs_header_flag(eb, BTRFS_HEADER_FLAG_RELOC) ||
2872 btrfs_header_backref_rev(eb) < BTRFS_MIXED_BACKREF_REV)
2873 return 1;
2874
2875 path = btrfs_alloc_path();
2876 BUG_ON(!path);
2877
2878 key.objectid = eb->start;
2879 key.type = BTRFS_EXTENT_ITEM_KEY;
2880 key.offset = eb->len;
2881
2882 path->search_commit_root = 1;
2883 path->skip_locking = 1;
2884 ret = btrfs_search_slot(NULL, rc->extent_root,
2885 &key, path, 0, 0);
2886 BUG_ON(ret);
2887
2888 ei = btrfs_item_ptr(path->nodes[0], path->slots[0],
2889 struct btrfs_extent_item);
2890 flags = btrfs_extent_flags(path->nodes[0], ei);
2891 BUG_ON(!(flags & BTRFS_EXTENT_FLAG_TREE_BLOCK));
2892 if (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF)
2893 ret = 1;
2894 else
2895 ret = 0;
2896 btrfs_free_path(path);
2897 return ret;
2898 }
2899
2900 /*
2901 * helper to add tree blocks for backref of type BTRFS_EXTENT_DATA_REF_KEY
2902 * this function scans fs tree to find blocks reference the data extent
2903 */
2904 static int find_data_references(struct reloc_control *rc,
2905 struct btrfs_key *extent_key,
2906 struct extent_buffer *leaf,
2907 struct btrfs_extent_data_ref *ref,
2908 struct rb_root *blocks)
2909 {
2910 struct btrfs_path *path;
2911 struct tree_block *block;
2912 struct btrfs_root *root;
2913 struct btrfs_file_extent_item *fi;
2914 struct rb_node *rb_node;
2915 struct btrfs_key key;
2916 u64 ref_root;
2917 u64 ref_objectid;
2918 u64 ref_offset;
2919 u32 ref_count;
2920 u32 nritems;
2921 int err = 0;
2922 int added = 0;
2923 int counted;
2924 int ret;
2925
2926 path = btrfs_alloc_path();
2927 if (!path)
2928 return -ENOMEM;
2929
2930 ref_root = btrfs_extent_data_ref_root(leaf, ref);
2931 ref_objectid = btrfs_extent_data_ref_objectid(leaf, ref);
2932 ref_offset = btrfs_extent_data_ref_offset(leaf, ref);
2933 ref_count = btrfs_extent_data_ref_count(leaf, ref);
2934
2935 root = read_fs_root(rc->extent_root->fs_info, ref_root);
2936 if (IS_ERR(root)) {
2937 err = PTR_ERR(root);
2938 goto out;
2939 }
2940
2941 key.objectid = ref_objectid;
2942 key.offset = ref_offset;
2943 key.type = BTRFS_EXTENT_DATA_KEY;
2944
2945 path->search_commit_root = 1;
2946 path->skip_locking = 1;
2947 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
2948 if (ret < 0) {
2949 err = ret;
2950 goto out;
2951 }
2952
2953 leaf = path->nodes[0];
2954 nritems = btrfs_header_nritems(leaf);
2955 /*
2956 * the references in tree blocks that use full backrefs
2957 * are not counted in
2958 */
2959 if (block_use_full_backref(rc, leaf))
2960 counted = 0;
2961 else
2962 counted = 1;
2963 rb_node = tree_search(blocks, leaf->start);
2964 if (rb_node) {
2965 if (counted)
2966 added = 1;
2967 else
2968 path->slots[0] = nritems;
2969 }
2970
2971 while (ref_count > 0) {
2972 while (path->slots[0] >= nritems) {
2973 ret = btrfs_next_leaf(root, path);
2974 if (ret < 0) {
2975 err = ret;
2976 goto out;
2977 }
2978 if (ret > 0) {
2979 WARN_ON(1);
2980 goto out;
2981 }
2982
2983 leaf = path->nodes[0];
2984 nritems = btrfs_header_nritems(leaf);
2985 added = 0;
2986
2987 if (block_use_full_backref(rc, leaf))
2988 counted = 0;
2989 else
2990 counted = 1;
2991 rb_node = tree_search(blocks, leaf->start);
2992 if (rb_node) {
2993 if (counted)
2994 added = 1;
2995 else
2996 path->slots[0] = nritems;
2997 }
2998 }
2999
3000 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
3001 if (key.objectid != ref_objectid ||
3002 key.type != BTRFS_EXTENT_DATA_KEY) {
3003 WARN_ON(1);
3004 break;
3005 }
3006
3007 fi = btrfs_item_ptr(leaf, path->slots[0],
3008 struct btrfs_file_extent_item);
3009
3010 if (btrfs_file_extent_type(leaf, fi) ==
3011 BTRFS_FILE_EXTENT_INLINE)
3012 goto next;
3013
3014 if (btrfs_file_extent_disk_bytenr(leaf, fi) !=
3015 extent_key->objectid)
3016 goto next;
3017
3018 key.offset -= btrfs_file_extent_offset(leaf, fi);
3019 if (key.offset != ref_offset)
3020 goto next;
3021
3022 if (counted)
3023 ref_count--;
3024 if (added)
3025 goto next;
3026
3027 if (!tree_block_processed(leaf->start, leaf->len, rc)) {
3028 block = kmalloc(sizeof(*block), GFP_NOFS);
3029 if (!block) {
3030 err = -ENOMEM;
3031 break;
3032 }
3033 block->bytenr = leaf->start;
3034 btrfs_item_key_to_cpu(leaf, &block->key, 0);
3035 block->level = 0;
3036 block->key_ready = 1;
3037 rb_node = tree_insert(blocks, block->bytenr,
3038 &block->rb_node);
3039 BUG_ON(rb_node);
3040 }
3041 if (counted)
3042 added = 1;
3043 else
3044 path->slots[0] = nritems;
3045 next:
3046 path->slots[0]++;
3047
3048 }
3049 out:
3050 btrfs_free_path(path);
3051 return err;
3052 }
3053
3054 /*
3055 * hepler to find all tree blocks that reference a given data extent
3056 */
3057 static noinline_for_stack
3058 int add_data_references(struct reloc_control *rc,
3059 struct btrfs_key *extent_key,
3060 struct btrfs_path *path,
3061 struct rb_root *blocks)
3062 {
3063 struct btrfs_key key;
3064 struct extent_buffer *eb;
3065 struct btrfs_extent_data_ref *dref;
3066 struct btrfs_extent_inline_ref *iref;
3067 unsigned long ptr;
3068 unsigned long end;
3069 u32 blocksize;
3070 int ret;
3071 int err = 0;
3072
3073 ret = get_new_location(rc->data_inode, NULL, extent_key->objectid,
3074 extent_key->offset);
3075 BUG_ON(ret < 0);
3076 if (ret > 0) {
3077 /* the relocated data is fragmented */
3078 rc->extents_skipped++;
3079 btrfs_release_path(rc->extent_root, path);
3080 return 0;
3081 }
3082
3083 blocksize = btrfs_level_size(rc->extent_root, 0);
3084
3085 eb = path->nodes[0];
3086 ptr = btrfs_item_ptr_offset(eb, path->slots[0]);
3087 end = ptr + btrfs_item_size_nr(eb, path->slots[0]);
3088 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
3089 if (ptr + sizeof(struct btrfs_extent_item_v0) == end)
3090 ptr = end;
3091 else
3092 #endif
3093 ptr += sizeof(struct btrfs_extent_item);
3094
3095 while (ptr < end) {
3096 iref = (struct btrfs_extent_inline_ref *)ptr;
3097 key.type = btrfs_extent_inline_ref_type(eb, iref);
3098 if (key.type == BTRFS_SHARED_DATA_REF_KEY) {
3099 key.offset = btrfs_extent_inline_ref_offset(eb, iref);
3100 ret = __add_tree_block(rc, key.offset, blocksize,
3101 blocks);
3102 } else if (key.type == BTRFS_EXTENT_DATA_REF_KEY) {
3103 dref = (struct btrfs_extent_data_ref *)(&iref->offset);
3104 ret = find_data_references(rc, extent_key,
3105 eb, dref, blocks);
3106 } else {
3107 BUG();
3108 }
3109 ptr += btrfs_extent_inline_ref_size(key.type);
3110 }
3111 WARN_ON(ptr > end);
3112
3113 while (1) {
3114 cond_resched();
3115 eb = path->nodes[0];
3116 if (path->slots[0] >= btrfs_header_nritems(eb)) {
3117 ret = btrfs_next_leaf(rc->extent_root, path);
3118 if (ret < 0) {
3119 err = ret;
3120 break;
3121 }
3122 if (ret > 0)
3123 break;
3124 eb = path->nodes[0];
3125 }
3126
3127 btrfs_item_key_to_cpu(eb, &key, path->slots[0]);
3128 if (key.objectid != extent_key->objectid)
3129 break;
3130
3131 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
3132 if (key.type == BTRFS_SHARED_DATA_REF_KEY ||
3133 key.type == BTRFS_EXTENT_REF_V0_KEY) {
3134 #else
3135 BUG_ON(key.type == BTRFS_EXTENT_REF_V0_KEY);
3136 if (key.type == BTRFS_SHARED_DATA_REF_KEY) {
3137 #endif
3138 ret = __add_tree_block(rc, key.offset, blocksize,
3139 blocks);
3140 } else if (key.type == BTRFS_EXTENT_DATA_REF_KEY) {
3141 dref = btrfs_item_ptr(eb, path->slots[0],
3142 struct btrfs_extent_data_ref);
3143 ret = find_data_references(rc, extent_key,
3144 eb, dref, blocks);
3145 } else {
3146 ret = 0;
3147 }
3148 if (ret) {
3149 err = ret;
3150 break;
3151 }
3152 path->slots[0]++;
3153 }
3154 btrfs_release_path(rc->extent_root, path);
3155 if (err)
3156 free_block_list(blocks);
3157 return err;
3158 }
3159
3160 /*
3161 * hepler to find next unprocessed extent
3162 */
3163 static noinline_for_stack
3164 int find_next_extent(struct btrfs_trans_handle *trans,
3165 struct reloc_control *rc, struct btrfs_path *path)
3166 {
3167 struct btrfs_key key;
3168 struct extent_buffer *leaf;
3169 u64 start, end, last;
3170 int ret;
3171
3172 last = rc->block_group->key.objectid + rc->block_group->key.offset;
3173 while (1) {
3174 cond_resched();
3175 if (rc->search_start >= last) {
3176 ret = 1;
3177 break;
3178 }
3179
3180 key.objectid = rc->search_start;
3181 key.type = BTRFS_EXTENT_ITEM_KEY;
3182 key.offset = 0;
3183
3184 path->search_commit_root = 1;
3185 path->skip_locking = 1;
3186 ret = btrfs_search_slot(NULL, rc->extent_root, &key, path,
3187 0, 0);
3188 if (ret < 0)
3189 break;
3190 next:
3191 leaf = path->nodes[0];
3192 if (path->slots[0] >= btrfs_header_nritems(leaf)) {
3193 ret = btrfs_next_leaf(rc->extent_root, path);
3194 if (ret != 0)
3195 break;
3196 leaf = path->nodes[0];
3197 }
3198
3199 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
3200 if (key.objectid >= last) {
3201 ret = 1;
3202 break;
3203 }
3204
3205 if (key.type != BTRFS_EXTENT_ITEM_KEY ||
3206 key.objectid + key.offset <= rc->search_start) {
3207 path->slots[0]++;
3208 goto next;
3209 }
3210
3211 ret = find_first_extent_bit(&rc->processed_blocks,
3212 key.objectid, &start, &end,
3213 EXTENT_DIRTY);
3214
3215 if (ret == 0 && start <= key.objectid) {
3216 btrfs_release_path(rc->extent_root, path);
3217 rc->search_start = end + 1;
3218 } else {
3219 rc->search_start = key.objectid + key.offset;
3220 return 0;
3221 }
3222 }
3223 btrfs_release_path(rc->extent_root, path);
3224 return ret;
3225 }
3226
3227 static void set_reloc_control(struct reloc_control *rc)
3228 {
3229 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
3230 mutex_lock(&fs_info->trans_mutex);
3231 fs_info->reloc_ctl = rc;
3232 mutex_unlock(&fs_info->trans_mutex);
3233 }
3234
3235 static void unset_reloc_control(struct reloc_control *rc)
3236 {
3237 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
3238 mutex_lock(&fs_info->trans_mutex);
3239 fs_info->reloc_ctl = NULL;
3240 mutex_unlock(&fs_info->trans_mutex);
3241 }
3242
3243 static int check_extent_flags(u64 flags)
3244 {
3245 if ((flags & BTRFS_EXTENT_FLAG_DATA) &&
3246 (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK))
3247 return 1;
3248 if (!(flags & BTRFS_EXTENT_FLAG_DATA) &&
3249 !(flags & BTRFS_EXTENT_FLAG_TREE_BLOCK))
3250 return 1;
3251 if ((flags & BTRFS_EXTENT_FLAG_DATA) &&
3252 (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF))
3253 return 1;
3254 return 0;
3255 }
3256
3257
3258 static noinline_for_stack int relocate_block_group(struct reloc_control *rc)
3259 {
3260 struct rb_root blocks = RB_ROOT;
3261 struct btrfs_key key;
3262 struct file_extent_cluster *cluster;
3263 struct btrfs_trans_handle *trans = NULL;
3264 struct btrfs_path *path;
3265 struct btrfs_extent_item *ei;
3266 unsigned long nr;
3267 u64 flags;
3268 u32 item_size;
3269 int ret;
3270 int err = 0;
3271
3272 cluster = kzalloc(sizeof(*cluster), GFP_NOFS);
3273 if (!cluster)
3274 return -ENOMEM;
3275
3276 path = btrfs_alloc_path();
3277 if (!path)
3278 return -ENOMEM;
3279
3280 rc->extents_found = 0;
3281 rc->extents_skipped = 0;
3282
3283 rc->search_start = rc->block_group->key.objectid;
3284 clear_extent_bits(&rc->processed_blocks, 0, (u64)-1, EXTENT_DIRTY,
3285 GFP_NOFS);
3286
3287 rc->create_reloc_root = 1;
3288 set_reloc_control(rc);
3289
3290 trans = btrfs_start_transaction(rc->extent_root, 1);
3291 btrfs_commit_transaction(trans, rc->extent_root);
3292
3293 while (1) {
3294 trans = btrfs_start_transaction(rc->extent_root, 1);
3295
3296 ret = find_next_extent(trans, rc, path);
3297 if (ret < 0)
3298 err = ret;
3299 if (ret != 0)
3300 break;
3301
3302 rc->extents_found++;
3303
3304 ei = btrfs_item_ptr(path->nodes[0], path->slots[0],
3305 struct btrfs_extent_item);
3306 btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
3307 item_size = btrfs_item_size_nr(path->nodes[0],
3308 path->slots[0]);
3309 if (item_size >= sizeof(*ei)) {
3310 flags = btrfs_extent_flags(path->nodes[0], ei);
3311 ret = check_extent_flags(flags);
3312 BUG_ON(ret);
3313
3314 } else {
3315 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
3316 u64 ref_owner;
3317 int path_change = 0;
3318
3319 BUG_ON(item_size !=
3320 sizeof(struct btrfs_extent_item_v0));
3321 ret = get_ref_objectid_v0(rc, path, &key, &ref_owner,
3322 &path_change);
3323 if (ref_owner < BTRFS_FIRST_FREE_OBJECTID)
3324 flags = BTRFS_EXTENT_FLAG_TREE_BLOCK;
3325 else
3326 flags = BTRFS_EXTENT_FLAG_DATA;
3327
3328 if (path_change) {
3329 btrfs_release_path(rc->extent_root, path);
3330
3331 path->search_commit_root = 1;
3332 path->skip_locking = 1;
3333 ret = btrfs_search_slot(NULL, rc->extent_root,
3334 &key, path, 0, 0);
3335 if (ret < 0) {
3336 err = ret;
3337 break;
3338 }
3339 BUG_ON(ret > 0);
3340 }
3341 #else
3342 BUG();
3343 #endif
3344 }
3345
3346 if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) {
3347 ret = add_tree_block(rc, &key, path, &blocks);
3348 } else if (rc->stage == UPDATE_DATA_PTRS &&
3349 (flags & BTRFS_EXTENT_FLAG_DATA)) {
3350 ret = add_data_references(rc, &key, path, &blocks);
3351 } else {
3352 btrfs_release_path(rc->extent_root, path);
3353 ret = 0;
3354 }
3355 if (ret < 0) {
3356 err = 0;
3357 break;
3358 }
3359
3360 if (!RB_EMPTY_ROOT(&blocks)) {
3361 ret = relocate_tree_blocks(trans, rc, &blocks);
3362 if (ret < 0) {
3363 err = ret;
3364 break;
3365 }
3366 }
3367
3368 nr = trans->blocks_used;
3369 btrfs_end_transaction(trans, rc->extent_root);
3370 trans = NULL;
3371 btrfs_btree_balance_dirty(rc->extent_root, nr);
3372
3373 if (rc->stage == MOVE_DATA_EXTENTS &&
3374 (flags & BTRFS_EXTENT_FLAG_DATA)) {
3375 rc->found_file_extent = 1;
3376 ret = relocate_data_extent(rc->data_inode,
3377 &key, cluster);
3378 if (ret < 0) {
3379 err = ret;
3380 break;
3381 }
3382 }
3383 }
3384 btrfs_free_path(path);
3385
3386 if (trans) {
3387 nr = trans->blocks_used;
3388 btrfs_end_transaction(trans, rc->extent_root);
3389 btrfs_btree_balance_dirty(rc->extent_root, nr);
3390 }
3391
3392 if (!err) {
3393 ret = relocate_file_extent_cluster(rc->data_inode, cluster);
3394 if (ret < 0)
3395 err = ret;
3396 }
3397
3398 kfree(cluster);
3399
3400 rc->create_reloc_root = 0;
3401 smp_mb();
3402
3403 if (rc->extents_found > 0) {
3404 trans = btrfs_start_transaction(rc->extent_root, 1);
3405 btrfs_commit_transaction(trans, rc->extent_root);
3406 }
3407
3408 merge_reloc_roots(rc);
3409
3410 unset_reloc_control(rc);
3411
3412 /* get rid of pinned extents */
3413 trans = btrfs_start_transaction(rc->extent_root, 1);
3414 btrfs_commit_transaction(trans, rc->extent_root);
3415
3416 return err;
3417 }
3418
3419 static int __insert_orphan_inode(struct btrfs_trans_handle *trans,
3420 struct btrfs_root *root, u64 objectid)
3421 {
3422 struct btrfs_path *path;
3423 struct btrfs_inode_item *item;
3424 struct extent_buffer *leaf;
3425 int ret;
3426
3427 path = btrfs_alloc_path();
3428 if (!path)
3429 return -ENOMEM;
3430
3431 ret = btrfs_insert_empty_inode(trans, root, path, objectid);
3432 if (ret)
3433 goto out;
3434
3435 leaf = path->nodes[0];
3436 item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_inode_item);
3437 memset_extent_buffer(leaf, 0, (unsigned long)item, sizeof(*item));
3438 btrfs_set_inode_generation(leaf, item, 1);
3439 btrfs_set_inode_size(leaf, item, 0);
3440 btrfs_set_inode_mode(leaf, item, S_IFREG | 0600);
3441 btrfs_set_inode_flags(leaf, item, BTRFS_INODE_NOCOMPRESS);
3442 btrfs_mark_buffer_dirty(leaf);
3443 btrfs_release_path(root, path);
3444 out:
3445 btrfs_free_path(path);
3446 return ret;
3447 }
3448
3449 /*
3450 * helper to create inode for data relocation.
3451 * the inode is in data relocation tree and its link count is 0
3452 */
3453 static struct inode *create_reloc_inode(struct btrfs_fs_info *fs_info,
3454 struct btrfs_block_group_cache *group)
3455 {
3456 struct inode *inode = NULL;
3457 struct btrfs_trans_handle *trans;
3458 struct btrfs_root *root;
3459 struct btrfs_key key;
3460 unsigned long nr;
3461 u64 objectid = BTRFS_FIRST_FREE_OBJECTID;
3462 int err = 0;
3463
3464 root = read_fs_root(fs_info, BTRFS_DATA_RELOC_TREE_OBJECTID);
3465 if (IS_ERR(root))
3466 return ERR_CAST(root);
3467
3468 trans = btrfs_start_transaction(root, 1);
3469 BUG_ON(!trans);
3470
3471 err = btrfs_find_free_objectid(trans, root, objectid, &objectid);
3472 if (err)
3473 goto out;
3474
3475 err = __insert_orphan_inode(trans, root, objectid);
3476 BUG_ON(err);
3477
3478 key.objectid = objectid;
3479 key.type = BTRFS_INODE_ITEM_KEY;
3480 key.offset = 0;
3481 inode = btrfs_iget(root->fs_info->sb, &key, root);
3482 BUG_ON(IS_ERR(inode) || is_bad_inode(inode));
3483 BTRFS_I(inode)->index_cnt = group->key.objectid;
3484
3485 err = btrfs_orphan_add(trans, inode);
3486 out:
3487 nr = trans->blocks_used;
3488 btrfs_end_transaction(trans, root);
3489
3490 btrfs_btree_balance_dirty(root, nr);
3491 if (err) {
3492 if (inode)
3493 iput(inode);
3494 inode = ERR_PTR(err);
3495 }
3496 return inode;
3497 }
3498
3499 /*
3500 * function to relocate all extents in a block group.
3501 */
3502 int btrfs_relocate_block_group(struct btrfs_root *extent_root, u64 group_start)
3503 {
3504 struct btrfs_fs_info *fs_info = extent_root->fs_info;
3505 struct reloc_control *rc;
3506 int ret;
3507 int err = 0;
3508
3509 rc = kzalloc(sizeof(*rc), GFP_NOFS);
3510 if (!rc)
3511 return -ENOMEM;
3512
3513 mapping_tree_init(&rc->reloc_root_tree);
3514 extent_io_tree_init(&rc->processed_blocks, NULL, GFP_NOFS);
3515 INIT_LIST_HEAD(&rc->reloc_roots);
3516
3517 rc->block_group = btrfs_lookup_block_group(fs_info, group_start);
3518 BUG_ON(!rc->block_group);
3519
3520 btrfs_init_workers(&rc->workers, "relocate",
3521 fs_info->thread_pool_size, NULL);
3522
3523 rc->extent_root = extent_root;
3524 btrfs_prepare_block_group_relocation(extent_root, rc->block_group);
3525
3526 rc->data_inode = create_reloc_inode(fs_info, rc->block_group);
3527 if (IS_ERR(rc->data_inode)) {
3528 err = PTR_ERR(rc->data_inode);
3529 rc->data_inode = NULL;
3530 goto out;
3531 }
3532
3533 printk(KERN_INFO "btrfs: relocating block group %llu flags %llu\n",
3534 (unsigned long long)rc->block_group->key.objectid,
3535 (unsigned long long)rc->block_group->flags);
3536
3537 btrfs_start_delalloc_inodes(fs_info->tree_root);
3538 btrfs_wait_ordered_extents(fs_info->tree_root, 0);
3539
3540 while (1) {
3541 rc->extents_found = 0;
3542 rc->extents_skipped = 0;
3543
3544 mutex_lock(&fs_info->cleaner_mutex);
3545
3546 btrfs_clean_old_snapshots(fs_info->tree_root);
3547 ret = relocate_block_group(rc);
3548
3549 mutex_unlock(&fs_info->cleaner_mutex);
3550 if (ret < 0) {
3551 err = ret;
3552 break;
3553 }
3554
3555 if (rc->extents_found == 0)
3556 break;
3557
3558 printk(KERN_INFO "btrfs: found %llu extents\n",
3559 (unsigned long long)rc->extents_found);
3560
3561 if (rc->stage == MOVE_DATA_EXTENTS && rc->found_file_extent) {
3562 btrfs_wait_ordered_range(rc->data_inode, 0, (u64)-1);
3563 invalidate_mapping_pages(rc->data_inode->i_mapping,
3564 0, -1);
3565 rc->stage = UPDATE_DATA_PTRS;
3566 } else if (rc->stage == UPDATE_DATA_PTRS &&
3567 rc->extents_skipped >= rc->extents_found) {
3568 iput(rc->data_inode);
3569 rc->data_inode = create_reloc_inode(fs_info,
3570 rc->block_group);
3571 if (IS_ERR(rc->data_inode)) {
3572 err = PTR_ERR(rc->data_inode);
3573 rc->data_inode = NULL;
3574 break;
3575 }
3576 rc->stage = MOVE_DATA_EXTENTS;
3577 rc->found_file_extent = 0;
3578 }
3579 }
3580
3581 filemap_write_and_wait_range(fs_info->btree_inode->i_mapping,
3582 rc->block_group->key.objectid,
3583 rc->block_group->key.objectid +
3584 rc->block_group->key.offset - 1);
3585
3586 WARN_ON(rc->block_group->pinned > 0);
3587 WARN_ON(rc->block_group->reserved > 0);
3588 WARN_ON(btrfs_block_group_used(&rc->block_group->item) > 0);
3589 out:
3590 iput(rc->data_inode);
3591 btrfs_stop_workers(&rc->workers);
3592 btrfs_put_block_group(rc->block_group);
3593 kfree(rc);
3594 return err;
3595 }
3596
3597 static noinline_for_stack int mark_garbage_root(struct btrfs_root *root)
3598 {
3599 struct btrfs_trans_handle *trans;
3600 int ret;
3601
3602 trans = btrfs_start_transaction(root->fs_info->tree_root, 1);
3603
3604 memset(&root->root_item.drop_progress, 0,
3605 sizeof(root->root_item.drop_progress));
3606 root->root_item.drop_level = 0;
3607 btrfs_set_root_refs(&root->root_item, 0);
3608 ret = btrfs_update_root(trans, root->fs_info->tree_root,
3609 &root->root_key, &root->root_item);
3610 BUG_ON(ret);
3611
3612 ret = btrfs_end_transaction(trans, root->fs_info->tree_root);
3613 BUG_ON(ret);
3614 return 0;
3615 }
3616
3617 /*
3618 * recover relocation interrupted by system crash.
3619 *
3620 * this function resumes merging reloc trees with corresponding fs trees.
3621 * this is important for keeping the sharing of tree blocks
3622 */
3623 int btrfs_recover_relocation(struct btrfs_root *root)
3624 {
3625 LIST_HEAD(reloc_roots);
3626 struct btrfs_key key;
3627 struct btrfs_root *fs_root;
3628 struct btrfs_root *reloc_root;
3629 struct btrfs_path *path;
3630 struct extent_buffer *leaf;
3631 struct reloc_control *rc = NULL;
3632 struct btrfs_trans_handle *trans;
3633 int ret;
3634 int err = 0;
3635
3636 path = btrfs_alloc_path();
3637 if (!path)
3638 return -ENOMEM;
3639
3640 key.objectid = BTRFS_TREE_RELOC_OBJECTID;
3641 key.type = BTRFS_ROOT_ITEM_KEY;
3642 key.offset = (u64)-1;
3643
3644 while (1) {
3645 ret = btrfs_search_slot(NULL, root->fs_info->tree_root, &key,
3646 path, 0, 0);
3647 if (ret < 0) {
3648 err = ret;
3649 goto out;
3650 }
3651 if (ret > 0) {
3652 if (path->slots[0] == 0)
3653 break;
3654 path->slots[0]--;
3655 }
3656 leaf = path->nodes[0];
3657 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
3658 btrfs_release_path(root->fs_info->tree_root, path);
3659
3660 if (key.objectid != BTRFS_TREE_RELOC_OBJECTID ||
3661 key.type != BTRFS_ROOT_ITEM_KEY)
3662 break;
3663
3664 reloc_root = btrfs_read_fs_root_no_radix(root, &key);
3665 if (IS_ERR(reloc_root)) {
3666 err = PTR_ERR(reloc_root);
3667 goto out;
3668 }
3669
3670 list_add(&reloc_root->root_list, &reloc_roots);
3671
3672 if (btrfs_root_refs(&reloc_root->root_item) > 0) {
3673 fs_root = read_fs_root(root->fs_info,
3674 reloc_root->root_key.offset);
3675 if (IS_ERR(fs_root)) {
3676 ret = PTR_ERR(fs_root);
3677 if (ret != -ENOENT) {
3678 err = ret;
3679 goto out;
3680 }
3681 mark_garbage_root(reloc_root);
3682 }
3683 }
3684
3685 if (key.offset == 0)
3686 break;
3687
3688 key.offset--;
3689 }
3690 btrfs_release_path(root->fs_info->tree_root, path);
3691
3692 if (list_empty(&reloc_roots))
3693 goto out;
3694
3695 rc = kzalloc(sizeof(*rc), GFP_NOFS);
3696 if (!rc) {
3697 err = -ENOMEM;
3698 goto out;
3699 }
3700
3701 mapping_tree_init(&rc->reloc_root_tree);
3702 INIT_LIST_HEAD(&rc->reloc_roots);
3703 btrfs_init_workers(&rc->workers, "relocate",
3704 root->fs_info->thread_pool_size, NULL);
3705 rc->extent_root = root->fs_info->extent_root;
3706
3707 set_reloc_control(rc);
3708
3709 while (!list_empty(&reloc_roots)) {
3710 reloc_root = list_entry(reloc_roots.next,
3711 struct btrfs_root, root_list);
3712 list_del(&reloc_root->root_list);
3713
3714 if (btrfs_root_refs(&reloc_root->root_item) == 0) {
3715 list_add_tail(&reloc_root->root_list,
3716 &rc->reloc_roots);
3717 continue;
3718 }
3719
3720 fs_root = read_fs_root(root->fs_info,
3721 reloc_root->root_key.offset);
3722 BUG_ON(IS_ERR(fs_root));
3723
3724 __add_reloc_root(reloc_root);
3725 fs_root->reloc_root = reloc_root;
3726 }
3727
3728 trans = btrfs_start_transaction(rc->extent_root, 1);
3729 btrfs_commit_transaction(trans, rc->extent_root);
3730
3731 merge_reloc_roots(rc);
3732
3733 unset_reloc_control(rc);
3734
3735 trans = btrfs_start_transaction(rc->extent_root, 1);
3736 btrfs_commit_transaction(trans, rc->extent_root);
3737 out:
3738 if (rc) {
3739 btrfs_stop_workers(&rc->workers);
3740 kfree(rc);
3741 }
3742 while (!list_empty(&reloc_roots)) {
3743 reloc_root = list_entry(reloc_roots.next,
3744 struct btrfs_root, root_list);
3745 list_del(&reloc_root->root_list);
3746 free_extent_buffer(reloc_root->node);
3747 free_extent_buffer(reloc_root->commit_root);
3748 kfree(reloc_root);
3749 }
3750 btrfs_free_path(path);
3751
3752 if (err == 0) {
3753 /* cleanup orphan inode in data relocation tree */
3754 fs_root = read_fs_root(root->fs_info,
3755 BTRFS_DATA_RELOC_TREE_OBJECTID);
3756 if (IS_ERR(fs_root))
3757 err = PTR_ERR(fs_root);
3758 }
3759 return err;
3760 }
3761
3762 /*
3763 * helper to add ordered checksum for data relocation.
3764 *
3765 * cloning checksum properly handles the nodatasum extents.
3766 * it also saves CPU time to re-calculate the checksum.
3767 */
3768 int btrfs_reloc_clone_csums(struct inode *inode, u64 file_pos, u64 len)
3769 {
3770 struct btrfs_ordered_sum *sums;
3771 struct btrfs_sector_sum *sector_sum;
3772 struct btrfs_ordered_extent *ordered;
3773 struct btrfs_root *root = BTRFS_I(inode)->root;
3774 size_t offset;
3775 int ret;
3776 u64 disk_bytenr;
3777 LIST_HEAD(list);
3778
3779 ordered = btrfs_lookup_ordered_extent(inode, file_pos);
3780 BUG_ON(ordered->file_offset != file_pos || ordered->len != len);
3781
3782 disk_bytenr = file_pos + BTRFS_I(inode)->index_cnt;
3783 ret = btrfs_lookup_csums_range(root->fs_info->csum_root, disk_bytenr,
3784 disk_bytenr + len - 1, &list);
3785
3786 while (!list_empty(&list)) {
3787 sums = list_entry(list.next, struct btrfs_ordered_sum, list);
3788 list_del_init(&sums->list);
3789
3790 sector_sum = sums->sums;
3791 sums->bytenr = ordered->start;
3792
3793 offset = 0;
3794 while (offset < sums->len) {
3795 sector_sum->bytenr += ordered->start - disk_bytenr;
3796 sector_sum++;
3797 offset += root->sectorsize;
3798 }
3799
3800 btrfs_add_ordered_sum(inode, ordered, sums);
3801 }
3802 btrfs_put_ordered_extent(ordered);
3803 return 0;
3804 }
mm of the moment repository