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perf bpf: Move perf_event_output() from stdio.h to bpf.h
[linux/fpc-iii.git] / fs / btrfs / relocation.c
bloba3f75b8926d4474aa1093ffdd852d422b853e2d2
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * Copyright (C) 2009 Oracle. All rights reserved.
4 */
5
6 #include <linux/sched.h>
7 #include <linux/pagemap.h>
8 #include <linux/writeback.h>
9 #include <linux/blkdev.h>
10 #include <linux/rbtree.h>
11 #include <linux/slab.h>
12 #include "ctree.h"
13 #include "disk-io.h"
14 #include "transaction.h"
15 #include "volumes.h"
16 #include "locking.h"
17 #include "btrfs_inode.h"
18 #include "async-thread.h"
19 #include "free-space-cache.h"
20 #include "inode-map.h"
21 #include "qgroup.h"
22 #include "print-tree.h"
23
24 /*
25 * backref_node, mapping_node and tree_block start with this
26 */
27 struct tree_entry {
28 struct rb_node rb_node;
29 u64 bytenr;
30 };
31
32 /*
33 * present a tree block in the backref cache
34 */
35 struct backref_node {
36 struct rb_node rb_node;
37 u64 bytenr;
38
39 u64 new_bytenr;
40 /* objectid of tree block owner, can be not uptodate */
41 u64 owner;
42 /* link to pending, changed or detached list */
43 struct list_head list;
44 /* list of upper level blocks reference this block */
45 struct list_head upper;
46 /* list of child blocks in the cache */
47 struct list_head lower;
48 /* NULL if this node is not tree root */
49 struct btrfs_root *root;
50 /* extent buffer got by COW the block */
51 struct extent_buffer *eb;
52 /* level of tree block */
53 unsigned int level:8;
54 /* is the block in non-reference counted tree */
55 unsigned int cowonly:1;
56 /* 1 if no child node in the cache */
57 unsigned int lowest:1;
58 /* is the extent buffer locked */
59 unsigned int locked:1;
60 /* has the block been processed */
61 unsigned int processed:1;
62 /* have backrefs of this block been checked */
63 unsigned int checked:1;
64 /*
65 * 1 if corresponding block has been cowed but some upper
66 * level block pointers may not point to the new location
67 */
68 unsigned int pending:1;
69 /*
70 * 1 if the backref node isn't connected to any other
71 * backref node.
72 */
73 unsigned int detached:1;
74 };
75
76 /*
77 * present a block pointer in the backref cache
78 */
79 struct backref_edge {
80 struct list_head list[2];
81 struct backref_node *node[2];
82 };
83
84 #define LOWER 0
85 #define UPPER 1
86 #define RELOCATION_RESERVED_NODES 256
87
88 struct backref_cache {
89 /* red black tree of all backref nodes in the cache */
90 struct rb_root rb_root;
91 /* for passing backref nodes to btrfs_reloc_cow_block */
92 struct backref_node *path[BTRFS_MAX_LEVEL];
93 /*
94 * list of blocks that have been cowed but some block
95 * pointers in upper level blocks may not reflect the
96 * new location
97 */
98 struct list_head pending[BTRFS_MAX_LEVEL];
99 /* list of backref nodes with no child node */
100 struct list_head leaves;
101 /* list of blocks that have been cowed in current transaction */
102 struct list_head changed;
103 /* list of detached backref node. */
104 struct list_head detached;
105
106 u64 last_trans;
107
108 int nr_nodes;
109 int nr_edges;
110 };
111
112 /*
113 * map address of tree root to tree
114 */
115 struct mapping_node {
116 struct rb_node rb_node;
117 u64 bytenr;
118 void *data;
119 };
120
121 struct mapping_tree {
122 struct rb_root rb_root;
123 spinlock_t lock;
124 };
125
126 /*
127 * present a tree block to process
128 */
129 struct tree_block {
130 struct rb_node rb_node;
131 u64 bytenr;
132 struct btrfs_key key;
133 unsigned int level:8;
134 unsigned int key_ready:1;
135 };
136
137 #define MAX_EXTENTS 128
138
139 struct file_extent_cluster {
140 u64 start;
141 u64 end;
142 u64 boundary[MAX_EXTENTS];
143 unsigned int nr;
144 };
145
146 struct reloc_control {
147 /* block group to relocate */
148 struct btrfs_block_group_cache *block_group;
149 /* extent tree */
150 struct btrfs_root *extent_root;
151 /* inode for moving data */
152 struct inode *data_inode;
153
154 struct btrfs_block_rsv *block_rsv;
155
156 struct backref_cache backref_cache;
157
158 struct file_extent_cluster cluster;
159 /* tree blocks have been processed */
160 struct extent_io_tree processed_blocks;
161 /* map start of tree root to corresponding reloc tree */
162 struct mapping_tree reloc_root_tree;
163 /* list of reloc trees */
164 struct list_head reloc_roots;
165 /* size of metadata reservation for merging reloc trees */
166 u64 merging_rsv_size;
167 /* size of relocated tree nodes */
168 u64 nodes_relocated;
169 /* reserved size for block group relocation*/
170 u64 reserved_bytes;
171
172 u64 search_start;
173 u64 extents_found;
174
175 unsigned int stage:8;
176 unsigned int create_reloc_tree:1;
177 unsigned int merge_reloc_tree:1;
178 unsigned int found_file_extent:1;
179 };
180
181 /* stages of data relocation */
182 #define MOVE_DATA_EXTENTS 0
183 #define UPDATE_DATA_PTRS 1
184
185 static void remove_backref_node(struct backref_cache *cache,
186 struct backref_node *node);
187 static void __mark_block_processed(struct reloc_control *rc,
188 struct backref_node *node);
189
190 static void mapping_tree_init(struct mapping_tree *tree)
191 {
192 tree->rb_root = RB_ROOT;
193 spin_lock_init(&tree->lock);
194 }
195
196 static void backref_cache_init(struct backref_cache *cache)
197 {
198 int i;
199 cache->rb_root = RB_ROOT;
200 for (i = 0; i < BTRFS_MAX_LEVEL; i++)
201 INIT_LIST_HEAD(&cache->pending[i]);
202 INIT_LIST_HEAD(&cache->changed);
203 INIT_LIST_HEAD(&cache->detached);
204 INIT_LIST_HEAD(&cache->leaves);
205 }
206
207 static void backref_cache_cleanup(struct backref_cache *cache)
208 {
209 struct backref_node *node;
210 int i;
211
212 while (!list_empty(&cache->detached)) {
213 node = list_entry(cache->detached.next,
214 struct backref_node, list);
215 remove_backref_node(cache, node);
216 }
217
218 while (!list_empty(&cache->leaves)) {
219 node = list_entry(cache->leaves.next,
220 struct backref_node, lower);
221 remove_backref_node(cache, node);
222 }
223
224 cache->last_trans = 0;
225
226 for (i = 0; i < BTRFS_MAX_LEVEL; i++)
227 ASSERT(list_empty(&cache->pending[i]));
228 ASSERT(list_empty(&cache->changed));
229 ASSERT(list_empty(&cache->detached));
230 ASSERT(RB_EMPTY_ROOT(&cache->rb_root));
231 ASSERT(!cache->nr_nodes);
232 ASSERT(!cache->nr_edges);
233 }
234
235 static struct backref_node *alloc_backref_node(struct backref_cache *cache)
236 {
237 struct backref_node *node;
238
239 node = kzalloc(sizeof(*node), GFP_NOFS);
240 if (node) {
241 INIT_LIST_HEAD(&node->list);
242 INIT_LIST_HEAD(&node->upper);
243 INIT_LIST_HEAD(&node->lower);
244 RB_CLEAR_NODE(&node->rb_node);
245 cache->nr_nodes++;
246 }
247 return node;
248 }
249
250 static void free_backref_node(struct backref_cache *cache,
251 struct backref_node *node)
252 {
253 if (node) {
254 cache->nr_nodes--;
255 kfree(node);
256 }
257 }
258
259 static struct backref_edge *alloc_backref_edge(struct backref_cache *cache)
260 {
261 struct backref_edge *edge;
262
263 edge = kzalloc(sizeof(*edge), GFP_NOFS);
264 if (edge)
265 cache->nr_edges++;
266 return edge;
267 }
268
269 static void free_backref_edge(struct backref_cache *cache,
270 struct backref_edge *edge)
271 {
272 if (edge) {
273 cache->nr_edges--;
274 kfree(edge);
275 }
276 }
277
278 static struct rb_node *tree_insert(struct rb_root *root, u64 bytenr,
279 struct rb_node *node)
280 {
281 struct rb_node **p = &root->rb_node;
282 struct rb_node *parent = NULL;
283 struct tree_entry *entry;
284
285 while (*p) {
286 parent = *p;
287 entry = rb_entry(parent, struct tree_entry, rb_node);
288
289 if (bytenr < entry->bytenr)
290 p = &(*p)->rb_left;
291 else if (bytenr > entry->bytenr)
292 p = &(*p)->rb_right;
293 else
294 return parent;
295 }
296
297 rb_link_node(node, parent, p);
298 rb_insert_color(node, root);
299 return NULL;
300 }
301
302 static struct rb_node *tree_search(struct rb_root *root, u64 bytenr)
303 {
304 struct rb_node *n = root->rb_node;
305 struct tree_entry *entry;
306
307 while (n) {
308 entry = rb_entry(n, struct tree_entry, rb_node);
309
310 if (bytenr < entry->bytenr)
311 n = n->rb_left;
312 else if (bytenr > entry->bytenr)
313 n = n->rb_right;
314 else
315 return n;
316 }
317 return NULL;
318 }
319
320 static void backref_tree_panic(struct rb_node *rb_node, int errno, u64 bytenr)
321 {
322
323 struct btrfs_fs_info *fs_info = NULL;
324 struct backref_node *bnode = rb_entry(rb_node, struct backref_node,
325 rb_node);
326 if (bnode->root)
327 fs_info = bnode->root->fs_info;
328 btrfs_panic(fs_info, errno,
329 "Inconsistency in backref cache found at offset %llu",
330 bytenr);
331 }
332
333 /*
334 * walk up backref nodes until reach node presents tree root
335 */
336 static struct backref_node *walk_up_backref(struct backref_node *node,
337 struct backref_edge *edges[],
338 int *index)
339 {
340 struct backref_edge *edge;
341 int idx = *index;
342
343 while (!list_empty(&node->upper)) {
344 edge = list_entry(node->upper.next,
345 struct backref_edge, list[LOWER]);
346 edges[idx++] = edge;
347 node = edge->node[UPPER];
348 }
349 BUG_ON(node->detached);
350 *index = idx;
351 return node;
352 }
353
354 /*
355 * walk down backref nodes to find start of next reference path
356 */
357 static struct backref_node *walk_down_backref(struct backref_edge *edges[],
358 int *index)
359 {
360 struct backref_edge *edge;
361 struct backref_node *lower;
362 int idx = *index;
363
364 while (idx > 0) {
365 edge = edges[idx - 1];
366 lower = edge->node[LOWER];
367 if (list_is_last(&edge->list[LOWER], &lower->upper)) {
368 idx--;
369 continue;
370 }
371 edge = list_entry(edge->list[LOWER].next,
372 struct backref_edge, list[LOWER]);
373 edges[idx - 1] = edge;
374 *index = idx;
375 return edge->node[UPPER];
376 }
377 *index = 0;
378 return NULL;
379 }
380
381 static void unlock_node_buffer(struct backref_node *node)
382 {
383 if (node->locked) {
384 btrfs_tree_unlock(node->eb);
385 node->locked = 0;
386 }
387 }
388
389 static void drop_node_buffer(struct backref_node *node)
390 {
391 if (node->eb) {
392 unlock_node_buffer(node);
393 free_extent_buffer(node->eb);
394 node->eb = NULL;
395 }
396 }
397
398 static void drop_backref_node(struct backref_cache *tree,
399 struct backref_node *node)
400 {
401 BUG_ON(!list_empty(&node->upper));
402
403 drop_node_buffer(node);
404 list_del(&node->list);
405 list_del(&node->lower);
406 if (!RB_EMPTY_NODE(&node->rb_node))
407 rb_erase(&node->rb_node, &tree->rb_root);
408 free_backref_node(tree, node);
409 }
410
411 /*
412 * remove a backref node from the backref cache
413 */
414 static void remove_backref_node(struct backref_cache *cache,
415 struct backref_node *node)
416 {
417 struct backref_node *upper;
418 struct backref_edge *edge;
419
420 if (!node)
421 return;
422
423 BUG_ON(!node->lowest && !node->detached);
424 while (!list_empty(&node->upper)) {
425 edge = list_entry(node->upper.next, struct backref_edge,
426 list[LOWER]);
427 upper = edge->node[UPPER];
428 list_del(&edge->list[LOWER]);
429 list_del(&edge->list[UPPER]);
430 free_backref_edge(cache, edge);
431
432 if (RB_EMPTY_NODE(&upper->rb_node)) {
433 BUG_ON(!list_empty(&node->upper));
434 drop_backref_node(cache, node);
435 node = upper;
436 node->lowest = 1;
437 continue;
438 }
439 /*
440 * add the node to leaf node list if no other
441 * child block cached.
442 */
443 if (list_empty(&upper->lower)) {
444 list_add_tail(&upper->lower, &cache->leaves);
445 upper->lowest = 1;
446 }
447 }
448
449 drop_backref_node(cache, node);
450 }
451
452 static void update_backref_node(struct backref_cache *cache,
453 struct backref_node *node, u64 bytenr)
454 {
455 struct rb_node *rb_node;
456 rb_erase(&node->rb_node, &cache->rb_root);
457 node->bytenr = bytenr;
458 rb_node = tree_insert(&cache->rb_root, node->bytenr, &node->rb_node);
459 if (rb_node)
460 backref_tree_panic(rb_node, -EEXIST, bytenr);
461 }
462
463 /*
464 * update backref cache after a transaction commit
465 */
466 static int update_backref_cache(struct btrfs_trans_handle *trans,
467 struct backref_cache *cache)
468 {
469 struct backref_node *node;
470 int level = 0;
471
472 if (cache->last_trans == 0) {
473 cache->last_trans = trans->transid;
474 return 0;
475 }
476
477 if (cache->last_trans == trans->transid)
478 return 0;
479
480 /*
481 * detached nodes are used to avoid unnecessary backref
482 * lookup. transaction commit changes the extent tree.
483 * so the detached nodes are no longer useful.
484 */
485 while (!list_empty(&cache->detached)) {
486 node = list_entry(cache->detached.next,
487 struct backref_node, list);
488 remove_backref_node(cache, node);
489 }
490
491 while (!list_empty(&cache->changed)) {
492 node = list_entry(cache->changed.next,
493 struct backref_node, list);
494 list_del_init(&node->list);
495 BUG_ON(node->pending);
496 update_backref_node(cache, node, node->new_bytenr);
497 }
498
499 /*
500 * some nodes can be left in the pending list if there were
501 * errors during processing the pending nodes.
502 */
503 for (level = 0; level < BTRFS_MAX_LEVEL; level++) {
504 list_for_each_entry(node, &cache->pending[level], list) {
505 BUG_ON(!node->pending);
506 if (node->bytenr == node->new_bytenr)
507 continue;
508 update_backref_node(cache, node, node->new_bytenr);
509 }
510 }
511
512 cache->last_trans = 0;
513 return 1;
514 }
515
516
517 static int should_ignore_root(struct btrfs_root *root)
518 {
519 struct btrfs_root *reloc_root;
520
521 if (!test_bit(BTRFS_ROOT_REF_COWS, &root->state))
522 return 0;
523
524 reloc_root = root->reloc_root;
525 if (!reloc_root)
526 return 0;
527
528 if (btrfs_root_last_snapshot(&reloc_root->root_item) ==
529 root->fs_info->running_transaction->transid - 1)
530 return 0;
531 /*
532 * if there is reloc tree and it was created in previous
533 * transaction backref lookup can find the reloc tree,
534 * so backref node for the fs tree root is useless for
535 * relocation.
536 */
537 return 1;
538 }
539 /*
540 * find reloc tree by address of tree root
541 */
542 static struct btrfs_root *find_reloc_root(struct reloc_control *rc,
543 u64 bytenr)
544 {
545 struct rb_node *rb_node;
546 struct mapping_node *node;
547 struct btrfs_root *root = NULL;
548
549 spin_lock(&rc->reloc_root_tree.lock);
550 rb_node = tree_search(&rc->reloc_root_tree.rb_root, bytenr);
551 if (rb_node) {
552 node = rb_entry(rb_node, struct mapping_node, rb_node);
553 root = (struct btrfs_root *)node->data;
554 }
555 spin_unlock(&rc->reloc_root_tree.lock);
556 return root;
557 }
558
559 static int is_cowonly_root(u64 root_objectid)
560 {
561 if (root_objectid == BTRFS_ROOT_TREE_OBJECTID ||
562 root_objectid == BTRFS_EXTENT_TREE_OBJECTID ||
563 root_objectid == BTRFS_CHUNK_TREE_OBJECTID ||
564 root_objectid == BTRFS_DEV_TREE_OBJECTID ||
565 root_objectid == BTRFS_TREE_LOG_OBJECTID ||
566 root_objectid == BTRFS_CSUM_TREE_OBJECTID ||
567 root_objectid == BTRFS_UUID_TREE_OBJECTID ||
568 root_objectid == BTRFS_QUOTA_TREE_OBJECTID ||
569 root_objectid == BTRFS_FREE_SPACE_TREE_OBJECTID)
570 return 1;
571 return 0;
572 }
573
574 static struct btrfs_root *read_fs_root(struct btrfs_fs_info *fs_info,
575 u64 root_objectid)
576 {
577 struct btrfs_key key;
578
579 key.objectid = root_objectid;
580 key.type = BTRFS_ROOT_ITEM_KEY;
581 if (is_cowonly_root(root_objectid))
582 key.offset = 0;
583 else
584 key.offset = (u64)-1;
585
586 return btrfs_get_fs_root(fs_info, &key, false);
587 }
588
589 static noinline_for_stack
590 int find_inline_backref(struct extent_buffer *leaf, int slot,
591 unsigned long *ptr, unsigned long *end)
592 {
593 struct btrfs_key key;
594 struct btrfs_extent_item *ei;
595 struct btrfs_tree_block_info *bi;
596 u32 item_size;
597
598 btrfs_item_key_to_cpu(leaf, &key, slot);
599
600 item_size = btrfs_item_size_nr(leaf, slot);
601 if (item_size < sizeof(*ei)) {
602 btrfs_print_v0_err(leaf->fs_info);
603 btrfs_handle_fs_error(leaf->fs_info, -EINVAL, NULL);
604 return 1;
605 }
606 ei = btrfs_item_ptr(leaf, slot, struct btrfs_extent_item);
607 WARN_ON(!(btrfs_extent_flags(leaf, ei) &
608 BTRFS_EXTENT_FLAG_TREE_BLOCK));
609
610 if (key.type == BTRFS_EXTENT_ITEM_KEY &&
611 item_size <= sizeof(*ei) + sizeof(*bi)) {
612 WARN_ON(item_size < sizeof(*ei) + sizeof(*bi));
613 return 1;
614 }
615 if (key.type == BTRFS_METADATA_ITEM_KEY &&
616 item_size <= sizeof(*ei)) {
617 WARN_ON(item_size < sizeof(*ei));
618 return 1;
619 }
620
621 if (key.type == BTRFS_EXTENT_ITEM_KEY) {
622 bi = (struct btrfs_tree_block_info *)(ei + 1);
623 *ptr = (unsigned long)(bi + 1);
624 } else {
625 *ptr = (unsigned long)(ei + 1);
626 }
627 *end = (unsigned long)ei + item_size;
628 return 0;
629 }
630
631 /*
632 * build backref tree for a given tree block. root of the backref tree
633 * corresponds the tree block, leaves of the backref tree correspond
634 * roots of b-trees that reference the tree block.
635 *
636 * the basic idea of this function is check backrefs of a given block
637 * to find upper level blocks that reference the block, and then check
638 * backrefs of these upper level blocks recursively. the recursion stop
639 * when tree root is reached or backrefs for the block is cached.
640 *
641 * NOTE: if we find backrefs for a block are cached, we know backrefs
642 * for all upper level blocks that directly/indirectly reference the
643 * block are also cached.
644 */
645 static noinline_for_stack
646 struct backref_node *build_backref_tree(struct reloc_control *rc,
647 struct btrfs_key *node_key,
648 int level, u64 bytenr)
649 {
650 struct backref_cache *cache = &rc->backref_cache;
651 struct btrfs_path *path1; /* For searching extent root */
652 struct btrfs_path *path2; /* For searching parent of TREE_BLOCK_REF */
653 struct extent_buffer *eb;
654 struct btrfs_root *root;
655 struct backref_node *cur;
656 struct backref_node *upper;
657 struct backref_node *lower;
658 struct backref_node *node = NULL;
659 struct backref_node *exist = NULL;
660 struct backref_edge *edge;
661 struct rb_node *rb_node;
662 struct btrfs_key key;
663 unsigned long end;
664 unsigned long ptr;
665 LIST_HEAD(list); /* Pending edge list, upper node needs to be checked */
666 LIST_HEAD(useless);
667 int cowonly;
668 int ret;
669 int err = 0;
670 bool need_check = true;
671
672 path1 = btrfs_alloc_path();
673 path2 = btrfs_alloc_path();
674 if (!path1 || !path2) {
675 err = -ENOMEM;
676 goto out;
677 }
678 path1->reada = READA_FORWARD;
679 path2->reada = READA_FORWARD;
680
681 node = alloc_backref_node(cache);
682 if (!node) {
683 err = -ENOMEM;
684 goto out;
685 }
686
687 node->bytenr = bytenr;
688 node->level = level;
689 node->lowest = 1;
690 cur = node;
691 again:
692 end = 0;
693 ptr = 0;
694 key.objectid = cur->bytenr;
695 key.type = BTRFS_METADATA_ITEM_KEY;
696 key.offset = (u64)-1;
697
698 path1->search_commit_root = 1;
699 path1->skip_locking = 1;
700 ret = btrfs_search_slot(NULL, rc->extent_root, &key, path1,
701 0, 0);
702 if (ret < 0) {
703 err = ret;
704 goto out;
705 }
706 ASSERT(ret);
707 ASSERT(path1->slots[0]);
708
709 path1->slots[0]--;
710
711 WARN_ON(cur->checked);
712 if (!list_empty(&cur->upper)) {
713 /*
714 * the backref was added previously when processing
715 * backref of type BTRFS_TREE_BLOCK_REF_KEY
716 */
717 ASSERT(list_is_singular(&cur->upper));
718 edge = list_entry(cur->upper.next, struct backref_edge,
719 list[LOWER]);
720 ASSERT(list_empty(&edge->list[UPPER]));
721 exist = edge->node[UPPER];
722 /*
723 * add the upper level block to pending list if we need
724 * check its backrefs
725 */
726 if (!exist->checked)
727 list_add_tail(&edge->list[UPPER], &list);
728 } else {
729 exist = NULL;
730 }
731
732 while (1) {
733 cond_resched();
734 eb = path1->nodes[0];
735
736 if (ptr >= end) {
737 if (path1->slots[0] >= btrfs_header_nritems(eb)) {
738 ret = btrfs_next_leaf(rc->extent_root, path1);
739 if (ret < 0) {
740 err = ret;
741 goto out;
742 }
743 if (ret > 0)
744 break;
745 eb = path1->nodes[0];
746 }
747
748 btrfs_item_key_to_cpu(eb, &key, path1->slots[0]);
749 if (key.objectid != cur->bytenr) {
750 WARN_ON(exist);
751 break;
752 }
753
754 if (key.type == BTRFS_EXTENT_ITEM_KEY ||
755 key.type == BTRFS_METADATA_ITEM_KEY) {
756 ret = find_inline_backref(eb, path1->slots[0],
757 &ptr, &end);
758 if (ret)
759 goto next;
760 }
761 }
762
763 if (ptr < end) {
764 /* update key for inline back ref */
765 struct btrfs_extent_inline_ref *iref;
766 int type;
767 iref = (struct btrfs_extent_inline_ref *)ptr;
768 type = btrfs_get_extent_inline_ref_type(eb, iref,
769 BTRFS_REF_TYPE_BLOCK);
770 if (type == BTRFS_REF_TYPE_INVALID) {
771 err = -EUCLEAN;
772 goto out;
773 }
774 key.type = type;
775 key.offset = btrfs_extent_inline_ref_offset(eb, iref);
776
777 WARN_ON(key.type != BTRFS_TREE_BLOCK_REF_KEY &&
778 key.type != BTRFS_SHARED_BLOCK_REF_KEY);
779 }
780
781 /*
782 * Parent node found and matches current inline ref, no need to
783 * rebuild this node for this inline ref.
784 */
785 if (exist &&
786 ((key.type == BTRFS_TREE_BLOCK_REF_KEY &&
787 exist->owner == key.offset) ||
788 (key.type == BTRFS_SHARED_BLOCK_REF_KEY &&
789 exist->bytenr == key.offset))) {
790 exist = NULL;
791 goto next;
792 }
793
794 /* SHARED_BLOCK_REF means key.offset is the parent bytenr */
795 if (key.type == BTRFS_SHARED_BLOCK_REF_KEY) {
796 if (key.objectid == key.offset) {
797 /*
798 * Only root blocks of reloc trees use backref
799 * pointing to itself.
800 */
801 root = find_reloc_root(rc, cur->bytenr);
802 ASSERT(root);
803 cur->root = root;
804 break;
805 }
806
807 edge = alloc_backref_edge(cache);
808 if (!edge) {
809 err = -ENOMEM;
810 goto out;
811 }
812 rb_node = tree_search(&cache->rb_root, key.offset);
813 if (!rb_node) {
814 upper = alloc_backref_node(cache);
815 if (!upper) {
816 free_backref_edge(cache, edge);
817 err = -ENOMEM;
818 goto out;
819 }
820 upper->bytenr = key.offset;
821 upper->level = cur->level + 1;
822 /*
823 * backrefs for the upper level block isn't
824 * cached, add the block to pending list
825 */
826 list_add_tail(&edge->list[UPPER], &list);
827 } else {
828 upper = rb_entry(rb_node, struct backref_node,
829 rb_node);
830 ASSERT(upper->checked);
831 INIT_LIST_HEAD(&edge->list[UPPER]);
832 }
833 list_add_tail(&edge->list[LOWER], &cur->upper);
834 edge->node[LOWER] = cur;
835 edge->node[UPPER] = upper;
836
837 goto next;
838 } else if (unlikely(key.type == BTRFS_EXTENT_REF_V0_KEY)) {
839 err = -EINVAL;
840 btrfs_print_v0_err(rc->extent_root->fs_info);
841 btrfs_handle_fs_error(rc->extent_root->fs_info, err,
842 NULL);
843 goto out;
844 } else if (key.type != BTRFS_TREE_BLOCK_REF_KEY) {
845 goto next;
846 }
847
848 /*
849 * key.type == BTRFS_TREE_BLOCK_REF_KEY, inline ref offset
850 * means the root objectid. We need to search the tree to get
851 * its parent bytenr.
852 */
853 root = read_fs_root(rc->extent_root->fs_info, key.offset);
854 if (IS_ERR(root)) {
855 err = PTR_ERR(root);
856 goto out;
857 }
858
859 if (!test_bit(BTRFS_ROOT_REF_COWS, &root->state))
860 cur->cowonly = 1;
861
862 if (btrfs_root_level(&root->root_item) == cur->level) {
863 /* tree root */
864 ASSERT(btrfs_root_bytenr(&root->root_item) ==
865 cur->bytenr);
866 if (should_ignore_root(root))
867 list_add(&cur->list, &useless);
868 else
869 cur->root = root;
870 break;
871 }
872
873 level = cur->level + 1;
874
875 /* Search the tree to find parent blocks referring the block. */
876 path2->search_commit_root = 1;
877 path2->skip_locking = 1;
878 path2->lowest_level = level;
879 ret = btrfs_search_slot(NULL, root, node_key, path2, 0, 0);
880 path2->lowest_level = 0;
881 if (ret < 0) {
882 err = ret;
883 goto out;
884 }
885 if (ret > 0 && path2->slots[level] > 0)
886 path2->slots[level]--;
887
888 eb = path2->nodes[level];
889 if (btrfs_node_blockptr(eb, path2->slots[level]) !=
890 cur->bytenr) {
891 btrfs_err(root->fs_info,
892 "couldn't find block (%llu) (level %d) in tree (%llu) with key (%llu %u %llu)",
893 cur->bytenr, level - 1,
894 root->root_key.objectid,
895 node_key->objectid, node_key->type,
896 node_key->offset);
897 err = -ENOENT;
898 goto out;
899 }
900 lower = cur;
901 need_check = true;
902
903 /* Add all nodes and edges in the path */
904 for (; level < BTRFS_MAX_LEVEL; level++) {
905 if (!path2->nodes[level]) {
906 ASSERT(btrfs_root_bytenr(&root->root_item) ==
907 lower->bytenr);
908 if (should_ignore_root(root))
909 list_add(&lower->list, &useless);
910 else
911 lower->root = root;
912 break;
913 }
914
915 edge = alloc_backref_edge(cache);
916 if (!edge) {
917 err = -ENOMEM;
918 goto out;
919 }
920
921 eb = path2->nodes[level];
922 rb_node = tree_search(&cache->rb_root, eb->start);
923 if (!rb_node) {
924 upper = alloc_backref_node(cache);
925 if (!upper) {
926 free_backref_edge(cache, edge);
927 err = -ENOMEM;
928 goto out;
929 }
930 upper->bytenr = eb->start;
931 upper->owner = btrfs_header_owner(eb);
932 upper->level = lower->level + 1;
933 if (!test_bit(BTRFS_ROOT_REF_COWS,
934 &root->state))
935 upper->cowonly = 1;
936
937 /*
938 * if we know the block isn't shared
939 * we can void checking its backrefs.
940 */
941 if (btrfs_block_can_be_shared(root, eb))
942 upper->checked = 0;
943 else
944 upper->checked = 1;
945
946 /*
947 * add the block to pending list if we
948 * need check its backrefs, we only do this once
949 * while walking up a tree as we will catch
950 * anything else later on.
951 */
952 if (!upper->checked && need_check) {
953 need_check = false;
954 list_add_tail(&edge->list[UPPER],
955 &list);
956 } else {
957 if (upper->checked)
958 need_check = true;
959 INIT_LIST_HEAD(&edge->list[UPPER]);
960 }
961 } else {
962 upper = rb_entry(rb_node, struct backref_node,
963 rb_node);
964 ASSERT(upper->checked);
965 INIT_LIST_HEAD(&edge->list[UPPER]);
966 if (!upper->owner)
967 upper->owner = btrfs_header_owner(eb);
968 }
969 list_add_tail(&edge->list[LOWER], &lower->upper);
970 edge->node[LOWER] = lower;
971 edge->node[UPPER] = upper;
972
973 if (rb_node)
974 break;
975 lower = upper;
976 upper = NULL;
977 }
978 btrfs_release_path(path2);
979 next:
980 if (ptr < end) {
981 ptr += btrfs_extent_inline_ref_size(key.type);
982 if (ptr >= end) {
983 WARN_ON(ptr > end);
984 ptr = 0;
985 end = 0;
986 }
987 }
988 if (ptr >= end)
989 path1->slots[0]++;
990 }
991 btrfs_release_path(path1);
992
993 cur->checked = 1;
994 WARN_ON(exist);
995
996 /* the pending list isn't empty, take the first block to process */
997 if (!list_empty(&list)) {
998 edge = list_entry(list.next, struct backref_edge, list[UPPER]);
999 list_del_init(&edge->list[UPPER]);
1000 cur = edge->node[UPPER];
1001 goto again;
1002 }
1003
1004 /*
1005 * everything goes well, connect backref nodes and insert backref nodes
1006 * into the cache.
1007 */
1008 ASSERT(node->checked);
1009 cowonly = node->cowonly;
1010 if (!cowonly) {
1011 rb_node = tree_insert(&cache->rb_root, node->bytenr,
1012 &node->rb_node);
1013 if (rb_node)
1014 backref_tree_panic(rb_node, -EEXIST, node->bytenr);
1015 list_add_tail(&node->lower, &cache->leaves);
1016 }
1017
1018 list_for_each_entry(edge, &node->upper, list[LOWER])
1019 list_add_tail(&edge->list[UPPER], &list);
1020
1021 while (!list_empty(&list)) {
1022 edge = list_entry(list.next, struct backref_edge, list[UPPER]);
1023 list_del_init(&edge->list[UPPER]);
1024 upper = edge->node[UPPER];
1025 if (upper->detached) {
1026 list_del(&edge->list[LOWER]);
1027 lower = edge->node[LOWER];
1028 free_backref_edge(cache, edge);
1029 if (list_empty(&lower->upper))
1030 list_add(&lower->list, &useless);
1031 continue;
1032 }
1033
1034 if (!RB_EMPTY_NODE(&upper->rb_node)) {
1035 if (upper->lowest) {
1036 list_del_init(&upper->lower);
1037 upper->lowest = 0;
1038 }
1039
1040 list_add_tail(&edge->list[UPPER], &upper->lower);
1041 continue;
1042 }
1043
1044 if (!upper->checked) {
1045 /*
1046 * Still want to blow up for developers since this is a
1047 * logic bug.
1048 */
1049 ASSERT(0);
1050 err = -EINVAL;
1051 goto out;
1052 }
1053 if (cowonly != upper->cowonly) {
1054 ASSERT(0);
1055 err = -EINVAL;
1056 goto out;
1057 }
1058
1059 if (!cowonly) {
1060 rb_node = tree_insert(&cache->rb_root, upper->bytenr,
1061 &upper->rb_node);
1062 if (rb_node)
1063 backref_tree_panic(rb_node, -EEXIST,
1064 upper->bytenr);
1065 }
1066
1067 list_add_tail(&edge->list[UPPER], &upper->lower);
1068
1069 list_for_each_entry(edge, &upper->upper, list[LOWER])
1070 list_add_tail(&edge->list[UPPER], &list);
1071 }
1072 /*
1073 * process useless backref nodes. backref nodes for tree leaves
1074 * are deleted from the cache. backref nodes for upper level
1075 * tree blocks are left in the cache to avoid unnecessary backref
1076 * lookup.
1077 */
1078 while (!list_empty(&useless)) {
1079 upper = list_entry(useless.next, struct backref_node, list);
1080 list_del_init(&upper->list);
1081 ASSERT(list_empty(&upper->upper));
1082 if (upper == node)
1083 node = NULL;
1084 if (upper->lowest) {
1085 list_del_init(&upper->lower);
1086 upper->lowest = 0;
1087 }
1088 while (!list_empty(&upper->lower)) {
1089 edge = list_entry(upper->lower.next,
1090 struct backref_edge, list[UPPER]);
1091 list_del(&edge->list[UPPER]);
1092 list_del(&edge->list[LOWER]);
1093 lower = edge->node[LOWER];
1094 free_backref_edge(cache, edge);
1095
1096 if (list_empty(&lower->upper))
1097 list_add(&lower->list, &useless);
1098 }
1099 __mark_block_processed(rc, upper);
1100 if (upper->level > 0) {
1101 list_add(&upper->list, &cache->detached);
1102 upper->detached = 1;
1103 } else {
1104 rb_erase(&upper->rb_node, &cache->rb_root);
1105 free_backref_node(cache, upper);
1106 }
1107 }
1108 out:
1109 btrfs_free_path(path1);
1110 btrfs_free_path(path2);
1111 if (err) {
1112 while (!list_empty(&useless)) {
1113 lower = list_entry(useless.next,
1114 struct backref_node, list);
1115 list_del_init(&lower->list);
1116 }
1117 while (!list_empty(&list)) {
1118 edge = list_first_entry(&list, struct backref_edge,
1119 list[UPPER]);
1120 list_del(&edge->list[UPPER]);
1121 list_del(&edge->list[LOWER]);
1122 lower = edge->node[LOWER];
1123 upper = edge->node[UPPER];
1124 free_backref_edge(cache, edge);
1125
1126 /*
1127 * Lower is no longer linked to any upper backref nodes
1128 * and isn't in the cache, we can free it ourselves.
1129 */
1130 if (list_empty(&lower->upper) &&
1131 RB_EMPTY_NODE(&lower->rb_node))
1132 list_add(&lower->list, &useless);
1133
1134 if (!RB_EMPTY_NODE(&upper->rb_node))
1135 continue;
1136
1137 /* Add this guy's upper edges to the list to process */
1138 list_for_each_entry(edge, &upper->upper, list[LOWER])
1139 list_add_tail(&edge->list[UPPER], &list);
1140 if (list_empty(&upper->upper))
1141 list_add(&upper->list, &useless);
1142 }
1143
1144 while (!list_empty(&useless)) {
1145 lower = list_entry(useless.next,
1146 struct backref_node, list);
1147 list_del_init(&lower->list);
1148 if (lower == node)
1149 node = NULL;
1150 free_backref_node(cache, lower);
1151 }
1152
1153 free_backref_node(cache, node);
1154 return ERR_PTR(err);
1155 }
1156 ASSERT(!node || !node->detached);
1157 return node;
1158 }
1159
1160 /*
1161 * helper to add backref node for the newly created snapshot.
1162 * the backref node is created by cloning backref node that
1163 * corresponds to root of source tree
1164 */
1165 static int clone_backref_node(struct btrfs_trans_handle *trans,
1166 struct reloc_control *rc,
1167 struct btrfs_root *src,
1168 struct btrfs_root *dest)
1169 {
1170 struct btrfs_root *reloc_root = src->reloc_root;
1171 struct backref_cache *cache = &rc->backref_cache;
1172 struct backref_node *node = NULL;
1173 struct backref_node *new_node;
1174 struct backref_edge *edge;
1175 struct backref_edge *new_edge;
1176 struct rb_node *rb_node;
1177
1178 if (cache->last_trans > 0)
1179 update_backref_cache(trans, cache);
1180
1181 rb_node = tree_search(&cache->rb_root, src->commit_root->start);
1182 if (rb_node) {
1183 node = rb_entry(rb_node, struct backref_node, rb_node);
1184 if (node->detached)
1185 node = NULL;
1186 else
1187 BUG_ON(node->new_bytenr != reloc_root->node->start);
1188 }
1189
1190 if (!node) {
1191 rb_node = tree_search(&cache->rb_root,
1192 reloc_root->commit_root->start);
1193 if (rb_node) {
1194 node = rb_entry(rb_node, struct backref_node,
1195 rb_node);
1196 BUG_ON(node->detached);
1197 }
1198 }
1199
1200 if (!node)
1201 return 0;
1202
1203 new_node = alloc_backref_node(cache);
1204 if (!new_node)
1205 return -ENOMEM;
1206
1207 new_node->bytenr = dest->node->start;
1208 new_node->level = node->level;
1209 new_node->lowest = node->lowest;
1210 new_node->checked = 1;
1211 new_node->root = dest;
1212
1213 if (!node->lowest) {
1214 list_for_each_entry(edge, &node->lower, list[UPPER]) {
1215 new_edge = alloc_backref_edge(cache);
1216 if (!new_edge)
1217 goto fail;
1218
1219 new_edge->node[UPPER] = new_node;
1220 new_edge->node[LOWER] = edge->node[LOWER];
1221 list_add_tail(&new_edge->list[UPPER],
1222 &new_node->lower);
1223 }
1224 } else {
1225 list_add_tail(&new_node->lower, &cache->leaves);
1226 }
1227
1228 rb_node = tree_insert(&cache->rb_root, new_node->bytenr,
1229 &new_node->rb_node);
1230 if (rb_node)
1231 backref_tree_panic(rb_node, -EEXIST, new_node->bytenr);
1232
1233 if (!new_node->lowest) {
1234 list_for_each_entry(new_edge, &new_node->lower, list[UPPER]) {
1235 list_add_tail(&new_edge->list[LOWER],
1236 &new_edge->node[LOWER]->upper);
1237 }
1238 }
1239 return 0;
1240 fail:
1241 while (!list_empty(&new_node->lower)) {
1242 new_edge = list_entry(new_node->lower.next,
1243 struct backref_edge, list[UPPER]);
1244 list_del(&new_edge->list[UPPER]);
1245 free_backref_edge(cache, new_edge);
1246 }
1247 free_backref_node(cache, new_node);
1248 return -ENOMEM;
1249 }
1250
1251 /*
1252 * helper to add 'address of tree root -> reloc tree' mapping
1253 */
1254 static int __must_check __add_reloc_root(struct btrfs_root *root)
1255 {
1256 struct btrfs_fs_info *fs_info = root->fs_info;
1257 struct rb_node *rb_node;
1258 struct mapping_node *node;
1259 struct reloc_control *rc = fs_info->reloc_ctl;
1260
1261 node = kmalloc(sizeof(*node), GFP_NOFS);
1262 if (!node)
1263 return -ENOMEM;
1264
1265 node->bytenr = root->node->start;
1266 node->data = root;
1267
1268 spin_lock(&rc->reloc_root_tree.lock);
1269 rb_node = tree_insert(&rc->reloc_root_tree.rb_root,
1270 node->bytenr, &node->rb_node);
1271 spin_unlock(&rc->reloc_root_tree.lock);
1272 if (rb_node) {
1273 btrfs_panic(fs_info, -EEXIST,
1274 "Duplicate root found for start=%llu while inserting into relocation tree",
1275 node->bytenr);
1276 }
1277
1278 list_add_tail(&root->root_list, &rc->reloc_roots);
1279 return 0;
1280 }
1281
1282 /*
1283 * helper to delete the 'address of tree root -> reloc tree'
1284 * mapping
1285 */
1286 static void __del_reloc_root(struct btrfs_root *root)
1287 {
1288 struct btrfs_fs_info *fs_info = root->fs_info;
1289 struct rb_node *rb_node;
1290 struct mapping_node *node = NULL;
1291 struct reloc_control *rc = fs_info->reloc_ctl;
1292
1293 if (rc && root->node) {
1294 spin_lock(&rc->reloc_root_tree.lock);
1295 rb_node = tree_search(&rc->reloc_root_tree.rb_root,
1296 root->node->start);
1297 if (rb_node) {
1298 node = rb_entry(rb_node, struct mapping_node, rb_node);
1299 rb_erase(&node->rb_node, &rc->reloc_root_tree.rb_root);
1300 }
1301 spin_unlock(&rc->reloc_root_tree.lock);
1302 if (!node)
1303 return;
1304 BUG_ON((struct btrfs_root *)node->data != root);
1305 }
1306
1307 spin_lock(&fs_info->trans_lock);
1308 list_del_init(&root->root_list);
1309 spin_unlock(&fs_info->trans_lock);
1310 kfree(node);
1311 }
1312
1313 /*
1314 * helper to update the 'address of tree root -> reloc tree'
1315 * mapping
1316 */
1317 static int __update_reloc_root(struct btrfs_root *root, u64 new_bytenr)
1318 {
1319 struct btrfs_fs_info *fs_info = root->fs_info;
1320 struct rb_node *rb_node;
1321 struct mapping_node *node = NULL;
1322 struct reloc_control *rc = fs_info->reloc_ctl;
1323
1324 spin_lock(&rc->reloc_root_tree.lock);
1325 rb_node = tree_search(&rc->reloc_root_tree.rb_root,
1326 root->node->start);
1327 if (rb_node) {
1328 node = rb_entry(rb_node, struct mapping_node, rb_node);
1329 rb_erase(&node->rb_node, &rc->reloc_root_tree.rb_root);
1330 }
1331 spin_unlock(&rc->reloc_root_tree.lock);
1332
1333 if (!node)
1334 return 0;
1335 BUG_ON((struct btrfs_root *)node->data != root);
1336
1337 spin_lock(&rc->reloc_root_tree.lock);
1338 node->bytenr = new_bytenr;
1339 rb_node = tree_insert(&rc->reloc_root_tree.rb_root,
1340 node->bytenr, &node->rb_node);
1341 spin_unlock(&rc->reloc_root_tree.lock);
1342 if (rb_node)
1343 backref_tree_panic(rb_node, -EEXIST, node->bytenr);
1344 return 0;
1345 }
1346
1347 static struct btrfs_root *create_reloc_root(struct btrfs_trans_handle *trans,
1348 struct btrfs_root *root, u64 objectid)
1349 {
1350 struct btrfs_fs_info *fs_info = root->fs_info;
1351 struct btrfs_root *reloc_root;
1352 struct extent_buffer *eb;
1353 struct btrfs_root_item *root_item;
1354 struct btrfs_key root_key;
1355 int ret;
1356
1357 root_item = kmalloc(sizeof(*root_item), GFP_NOFS);
1358 BUG_ON(!root_item);
1359
1360 root_key.objectid = BTRFS_TREE_RELOC_OBJECTID;
1361 root_key.type = BTRFS_ROOT_ITEM_KEY;
1362 root_key.offset = objectid;
1363
1364 if (root->root_key.objectid == objectid) {
1365 u64 commit_root_gen;
1366
1367 /* called by btrfs_init_reloc_root */
1368 ret = btrfs_copy_root(trans, root, root->commit_root, &eb,
1369 BTRFS_TREE_RELOC_OBJECTID);
1370 BUG_ON(ret);
1371 /*
1372 * Set the last_snapshot field to the generation of the commit
1373 * root - like this ctree.c:btrfs_block_can_be_shared() behaves
1374 * correctly (returns true) when the relocation root is created
1375 * either inside the critical section of a transaction commit
1376 * (through transaction.c:qgroup_account_snapshot()) and when
1377 * it's created before the transaction commit is started.
1378 */
1379 commit_root_gen = btrfs_header_generation(root->commit_root);
1380 btrfs_set_root_last_snapshot(&root->root_item, commit_root_gen);
1381 } else {
1382 /*
1383 * called by btrfs_reloc_post_snapshot_hook.
1384 * the source tree is a reloc tree, all tree blocks
1385 * modified after it was created have RELOC flag
1386 * set in their headers. so it's OK to not update
1387 * the 'last_snapshot'.
1388 */
1389 ret = btrfs_copy_root(trans, root, root->node, &eb,
1390 BTRFS_TREE_RELOC_OBJECTID);
1391 BUG_ON(ret);
1392 }
1393
1394 memcpy(root_item, &root->root_item, sizeof(*root_item));
1395 btrfs_set_root_bytenr(root_item, eb->start);
1396 btrfs_set_root_level(root_item, btrfs_header_level(eb));
1397 btrfs_set_root_generation(root_item, trans->transid);
1398
1399 if (root->root_key.objectid == objectid) {
1400 btrfs_set_root_refs(root_item, 0);
1401 memset(&root_item->drop_progress, 0,
1402 sizeof(struct btrfs_disk_key));
1403 root_item->drop_level = 0;
1404 }
1405
1406 btrfs_tree_unlock(eb);
1407 free_extent_buffer(eb);
1408
1409 ret = btrfs_insert_root(trans, fs_info->tree_root,
1410 &root_key, root_item);
1411 BUG_ON(ret);
1412 kfree(root_item);
1413
1414 reloc_root = btrfs_read_fs_root(fs_info->tree_root, &root_key);
1415 BUG_ON(IS_ERR(reloc_root));
1416 reloc_root->last_trans = trans->transid;
1417 return reloc_root;
1418 }
1419
1420 /*
1421 * create reloc tree for a given fs tree. reloc tree is just a
1422 * snapshot of the fs tree with special root objectid.
1423 */
1424 int btrfs_init_reloc_root(struct btrfs_trans_handle *trans,
1425 struct btrfs_root *root)
1426 {
1427 struct btrfs_fs_info *fs_info = root->fs_info;
1428 struct btrfs_root *reloc_root;
1429 struct reloc_control *rc = fs_info->reloc_ctl;
1430 struct btrfs_block_rsv *rsv;
1431 int clear_rsv = 0;
1432 int ret;
1433
1434 if (root->reloc_root) {
1435 reloc_root = root->reloc_root;
1436 reloc_root->last_trans = trans->transid;
1437 return 0;
1438 }
1439
1440 if (!rc || !rc->create_reloc_tree ||
1441 root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID)
1442 return 0;
1443
1444 if (!trans->reloc_reserved) {
1445 rsv = trans->block_rsv;
1446 trans->block_rsv = rc->block_rsv;
1447 clear_rsv = 1;
1448 }
1449 reloc_root = create_reloc_root(trans, root, root->root_key.objectid);
1450 if (clear_rsv)
1451 trans->block_rsv = rsv;
1452
1453 ret = __add_reloc_root(reloc_root);
1454 BUG_ON(ret < 0);
1455 root->reloc_root = reloc_root;
1456 return 0;
1457 }
1458
1459 /*
1460 * update root item of reloc tree
1461 */
1462 int btrfs_update_reloc_root(struct btrfs_trans_handle *trans,
1463 struct btrfs_root *root)
1464 {
1465 struct btrfs_fs_info *fs_info = root->fs_info;
1466 struct btrfs_root *reloc_root;
1467 struct btrfs_root_item *root_item;
1468 int ret;
1469
1470 if (!root->reloc_root)
1471 goto out;
1472
1473 reloc_root = root->reloc_root;
1474 root_item = &reloc_root->root_item;
1475
1476 if (fs_info->reloc_ctl->merge_reloc_tree &&
1477 btrfs_root_refs(root_item) == 0) {
1478 root->reloc_root = NULL;
1479 __del_reloc_root(reloc_root);
1480 }
1481
1482 if (reloc_root->commit_root != reloc_root->node) {
1483 btrfs_set_root_node(root_item, reloc_root->node);
1484 free_extent_buffer(reloc_root->commit_root);
1485 reloc_root->commit_root = btrfs_root_node(reloc_root);
1486 }
1487
1488 ret = btrfs_update_root(trans, fs_info->tree_root,
1489 &reloc_root->root_key, root_item);
1490 BUG_ON(ret);
1491
1492 out:
1493 return 0;
1494 }
1495
1496 /*
1497 * helper to find first cached inode with inode number >= objectid
1498 * in a subvolume
1499 */
1500 static struct inode *find_next_inode(struct btrfs_root *root, u64 objectid)
1501 {
1502 struct rb_node *node;
1503 struct rb_node *prev;
1504 struct btrfs_inode *entry;
1505 struct inode *inode;
1506
1507 spin_lock(&root->inode_lock);
1508 again:
1509 node = root->inode_tree.rb_node;
1510 prev = NULL;
1511 while (node) {
1512 prev = node;
1513 entry = rb_entry(node, struct btrfs_inode, rb_node);
1514
1515 if (objectid < btrfs_ino(entry))
1516 node = node->rb_left;
1517 else if (objectid > btrfs_ino(entry))
1518 node = node->rb_right;
1519 else
1520 break;
1521 }
1522 if (!node) {
1523 while (prev) {
1524 entry = rb_entry(prev, struct btrfs_inode, rb_node);
1525 if (objectid <= btrfs_ino(entry)) {
1526 node = prev;
1527 break;
1528 }
1529 prev = rb_next(prev);
1530 }
1531 }
1532 while (node) {
1533 entry = rb_entry(node, struct btrfs_inode, rb_node);
1534 inode = igrab(&entry->vfs_inode);
1535 if (inode) {
1536 spin_unlock(&root->inode_lock);
1537 return inode;
1538 }
1539
1540 objectid = btrfs_ino(entry) + 1;
1541 if (cond_resched_lock(&root->inode_lock))
1542 goto again;
1543
1544 node = rb_next(node);
1545 }
1546 spin_unlock(&root->inode_lock);
1547 return NULL;
1548 }
1549
1550 static int in_block_group(u64 bytenr,
1551 struct btrfs_block_group_cache *block_group)
1552 {
1553 if (bytenr >= block_group->key.objectid &&
1554 bytenr < block_group->key.objectid + block_group->key.offset)
1555 return 1;
1556 return 0;
1557 }
1558
1559 /*
1560 * get new location of data
1561 */
1562 static int get_new_location(struct inode *reloc_inode, u64 *new_bytenr,
1563 u64 bytenr, u64 num_bytes)
1564 {
1565 struct btrfs_root *root = BTRFS_I(reloc_inode)->root;
1566 struct btrfs_path *path;
1567 struct btrfs_file_extent_item *fi;
1568 struct extent_buffer *leaf;
1569 int ret;
1570
1571 path = btrfs_alloc_path();
1572 if (!path)
1573 return -ENOMEM;
1574
1575 bytenr -= BTRFS_I(reloc_inode)->index_cnt;
1576 ret = btrfs_lookup_file_extent(NULL, root, path,
1577 btrfs_ino(BTRFS_I(reloc_inode)), bytenr, 0);
1578 if (ret < 0)
1579 goto out;
1580 if (ret > 0) {
1581 ret = -ENOENT;
1582 goto out;
1583 }
1584
1585 leaf = path->nodes[0];
1586 fi = btrfs_item_ptr(leaf, path->slots[0],
1587 struct btrfs_file_extent_item);
1588
1589 BUG_ON(btrfs_file_extent_offset(leaf, fi) ||
1590 btrfs_file_extent_compression(leaf, fi) ||
1591 btrfs_file_extent_encryption(leaf, fi) ||
1592 btrfs_file_extent_other_encoding(leaf, fi));
1593
1594 if (num_bytes != btrfs_file_extent_disk_num_bytes(leaf, fi)) {
1595 ret = -EINVAL;
1596 goto out;
1597 }
1598
1599 *new_bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
1600 ret = 0;
1601 out:
1602 btrfs_free_path(path);
1603 return ret;
1604 }
1605
1606 /*
1607 * update file extent items in the tree leaf to point to
1608 * the new locations.
1609 */
1610 static noinline_for_stack
1611 int replace_file_extents(struct btrfs_trans_handle *trans,
1612 struct reloc_control *rc,
1613 struct btrfs_root *root,
1614 struct extent_buffer *leaf)
1615 {
1616 struct btrfs_fs_info *fs_info = root->fs_info;
1617 struct btrfs_key key;
1618 struct btrfs_file_extent_item *fi;
1619 struct inode *inode = NULL;
1620 u64 parent;
1621 u64 bytenr;
1622 u64 new_bytenr = 0;
1623 u64 num_bytes;
1624 u64 end;
1625 u32 nritems;
1626 u32 i;
1627 int ret = 0;
1628 int first = 1;
1629 int dirty = 0;
1630
1631 if (rc->stage != UPDATE_DATA_PTRS)
1632 return 0;
1633
1634 /* reloc trees always use full backref */
1635 if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID)
1636 parent = leaf->start;
1637 else
1638 parent = 0;
1639
1640 nritems = btrfs_header_nritems(leaf);
1641 for (i = 0; i < nritems; i++) {
1642 cond_resched();
1643 btrfs_item_key_to_cpu(leaf, &key, i);
1644 if (key.type != BTRFS_EXTENT_DATA_KEY)
1645 continue;
1646 fi = btrfs_item_ptr(leaf, i, struct btrfs_file_extent_item);
1647 if (btrfs_file_extent_type(leaf, fi) ==
1648 BTRFS_FILE_EXTENT_INLINE)
1649 continue;
1650 bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
1651 num_bytes = btrfs_file_extent_disk_num_bytes(leaf, fi);
1652 if (bytenr == 0)
1653 continue;
1654 if (!in_block_group(bytenr, rc->block_group))
1655 continue;
1656
1657 /*
1658 * if we are modifying block in fs tree, wait for readpage
1659 * to complete and drop the extent cache
1660 */
1661 if (root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID) {
1662 if (first) {
1663 inode = find_next_inode(root, key.objectid);
1664 first = 0;
1665 } else if (inode && btrfs_ino(BTRFS_I(inode)) < key.objectid) {
1666 btrfs_add_delayed_iput(inode);
1667 inode = find_next_inode(root, key.objectid);
1668 }
1669 if (inode && btrfs_ino(BTRFS_I(inode)) == key.objectid) {
1670 end = key.offset +
1671 btrfs_file_extent_num_bytes(leaf, fi);
1672 WARN_ON(!IS_ALIGNED(key.offset,
1673 fs_info->sectorsize));
1674 WARN_ON(!IS_ALIGNED(end, fs_info->sectorsize));
1675 end--;
1676 ret = try_lock_extent(&BTRFS_I(inode)->io_tree,
1677 key.offset, end);
1678 if (!ret)
1679 continue;
1680
1681 btrfs_drop_extent_cache(BTRFS_I(inode),
1682 key.offset, end, 1);
1683 unlock_extent(&BTRFS_I(inode)->io_tree,
1684 key.offset, end);
1685 }
1686 }
1687
1688 ret = get_new_location(rc->data_inode, &new_bytenr,
1689 bytenr, num_bytes);
1690 if (ret) {
1691 /*
1692 * Don't have to abort since we've not changed anything
1693 * in the file extent yet.
1694 */
1695 break;
1696 }
1697
1698 btrfs_set_file_extent_disk_bytenr(leaf, fi, new_bytenr);
1699 dirty = 1;
1700
1701 key.offset -= btrfs_file_extent_offset(leaf, fi);
1702 ret = btrfs_inc_extent_ref(trans, root, new_bytenr,
1703 num_bytes, parent,
1704 btrfs_header_owner(leaf),
1705 key.objectid, key.offset);
1706 if (ret) {
1707 btrfs_abort_transaction(trans, ret);
1708 break;
1709 }
1710
1711 ret = btrfs_free_extent(trans, root, bytenr, num_bytes,
1712 parent, btrfs_header_owner(leaf),
1713 key.objectid, key.offset);
1714 if (ret) {
1715 btrfs_abort_transaction(trans, ret);
1716 break;
1717 }
1718 }
1719 if (dirty)
1720 btrfs_mark_buffer_dirty(leaf);
1721 if (inode)
1722 btrfs_add_delayed_iput(inode);
1723 return ret;
1724 }
1725
1726 static noinline_for_stack
1727 int memcmp_node_keys(struct extent_buffer *eb, int slot,
1728 struct btrfs_path *path, int level)
1729 {
1730 struct btrfs_disk_key key1;
1731 struct btrfs_disk_key key2;
1732 btrfs_node_key(eb, &key1, slot);
1733 btrfs_node_key(path->nodes[level], &key2, path->slots[level]);
1734 return memcmp(&key1, &key2, sizeof(key1));
1735 }
1736
1737 /*
1738 * try to replace tree blocks in fs tree with the new blocks
1739 * in reloc tree. tree blocks haven't been modified since the
1740 * reloc tree was create can be replaced.
1741 *
1742 * if a block was replaced, level of the block + 1 is returned.
1743 * if no block got replaced, 0 is returned. if there are other
1744 * errors, a negative error number is returned.
1745 */
1746 static noinline_for_stack
1747 int replace_path(struct btrfs_trans_handle *trans, struct reloc_control *rc,
1748 struct btrfs_root *dest, struct btrfs_root *src,
1749 struct btrfs_path *path, struct btrfs_key *next_key,
1750 int lowest_level, int max_level)
1751 {
1752 struct btrfs_fs_info *fs_info = dest->fs_info;
1753 struct extent_buffer *eb;
1754 struct extent_buffer *parent;
1755 struct btrfs_key key;
1756 u64 old_bytenr;
1757 u64 new_bytenr;
1758 u64 old_ptr_gen;
1759 u64 new_ptr_gen;
1760 u64 last_snapshot;
1761 u32 blocksize;
1762 int cow = 0;
1763 int level;
1764 int ret;
1765 int slot;
1766
1767 BUG_ON(src->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID);
1768 BUG_ON(dest->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID);
1769
1770 last_snapshot = btrfs_root_last_snapshot(&src->root_item);
1771 again:
1772 slot = path->slots[lowest_level];
1773 btrfs_node_key_to_cpu(path->nodes[lowest_level], &key, slot);
1774
1775 eb = btrfs_lock_root_node(dest);
1776 btrfs_set_lock_blocking(eb);
1777 level = btrfs_header_level(eb);
1778
1779 if (level < lowest_level) {
1780 btrfs_tree_unlock(eb);
1781 free_extent_buffer(eb);
1782 return 0;
1783 }
1784
1785 if (cow) {
1786 ret = btrfs_cow_block(trans, dest, eb, NULL, 0, &eb);
1787 BUG_ON(ret);
1788 }
1789 btrfs_set_lock_blocking(eb);
1790
1791 if (next_key) {
1792 next_key->objectid = (u64)-1;
1793 next_key->type = (u8)-1;
1794 next_key->offset = (u64)-1;
1795 }
1796
1797 parent = eb;
1798 while (1) {
1799 struct btrfs_key first_key;
1800
1801 level = btrfs_header_level(parent);
1802 BUG_ON(level < lowest_level);
1803
1804 ret = btrfs_bin_search(parent, &key, level, &slot);
1805 if (ret && slot > 0)
1806 slot--;
1807
1808 if (next_key && slot + 1 < btrfs_header_nritems(parent))
1809 btrfs_node_key_to_cpu(parent, next_key, slot + 1);
1810
1811 old_bytenr = btrfs_node_blockptr(parent, slot);
1812 blocksize = fs_info->nodesize;
1813 old_ptr_gen = btrfs_node_ptr_generation(parent, slot);
1814 btrfs_node_key_to_cpu(parent, &first_key, slot);
1815
1816 if (level <= max_level) {
1817 eb = path->nodes[level];
1818 new_bytenr = btrfs_node_blockptr(eb,
1819 path->slots[level]);
1820 new_ptr_gen = btrfs_node_ptr_generation(eb,
1821 path->slots[level]);
1822 } else {
1823 new_bytenr = 0;
1824 new_ptr_gen = 0;
1825 }
1826
1827 if (WARN_ON(new_bytenr > 0 && new_bytenr == old_bytenr)) {
1828 ret = level;
1829 break;
1830 }
1831
1832 if (new_bytenr == 0 || old_ptr_gen > last_snapshot ||
1833 memcmp_node_keys(parent, slot, path, level)) {
1834 if (level <= lowest_level) {
1835 ret = 0;
1836 break;
1837 }
1838
1839 eb = read_tree_block(fs_info, old_bytenr, old_ptr_gen,
1840 level - 1, &first_key);
1841 if (IS_ERR(eb)) {
1842 ret = PTR_ERR(eb);
1843 break;
1844 } else if (!extent_buffer_uptodate(eb)) {
1845 ret = -EIO;
1846 free_extent_buffer(eb);
1847 break;
1848 }
1849 btrfs_tree_lock(eb);
1850 if (cow) {
1851 ret = btrfs_cow_block(trans, dest, eb, parent,
1852 slot, &eb);
1853 BUG_ON(ret);
1854 }
1855 btrfs_set_lock_blocking(eb);
1856
1857 btrfs_tree_unlock(parent);
1858 free_extent_buffer(parent);
1859
1860 parent = eb;
1861 continue;
1862 }
1863
1864 if (!cow) {
1865 btrfs_tree_unlock(parent);
1866 free_extent_buffer(parent);
1867 cow = 1;
1868 goto again;
1869 }
1870
1871 btrfs_node_key_to_cpu(path->nodes[level], &key,
1872 path->slots[level]);
1873 btrfs_release_path(path);
1874
1875 path->lowest_level = level;
1876 ret = btrfs_search_slot(trans, src, &key, path, 0, 1);
1877 path->lowest_level = 0;
1878 BUG_ON(ret);
1879
1880 /*
1881 * Info qgroup to trace both subtrees.
1882 *
1883 * We must trace both trees.
1884 * 1) Tree reloc subtree
1885 * If not traced, we will leak data numbers
1886 * 2) Fs subtree
1887 * If not traced, we will double count old data
1888 * and tree block numbers, if current trans doesn't free
1889 * data reloc tree inode.
1890 */
1891 ret = btrfs_qgroup_trace_subtree_swap(trans, rc->block_group,
1892 parent, slot, path->nodes[level],
1893 path->slots[level], last_snapshot);
1894 if (ret < 0)
1895 break;
1896
1897 /*
1898 * swap blocks in fs tree and reloc tree.
1899 */
1900 btrfs_set_node_blockptr(parent, slot, new_bytenr);
1901 btrfs_set_node_ptr_generation(parent, slot, new_ptr_gen);
1902 btrfs_mark_buffer_dirty(parent);
1903
1904 btrfs_set_node_blockptr(path->nodes[level],
1905 path->slots[level], old_bytenr);
1906 btrfs_set_node_ptr_generation(path->nodes[level],
1907 path->slots[level], old_ptr_gen);
1908 btrfs_mark_buffer_dirty(path->nodes[level]);
1909
1910 ret = btrfs_inc_extent_ref(trans, src, old_bytenr,
1911 blocksize, path->nodes[level]->start,
1912 src->root_key.objectid, level - 1, 0);
1913 BUG_ON(ret);
1914 ret = btrfs_inc_extent_ref(trans, dest, new_bytenr,
1915 blocksize, 0, dest->root_key.objectid,
1916 level - 1, 0);
1917 BUG_ON(ret);
1918
1919 ret = btrfs_free_extent(trans, src, new_bytenr, blocksize,
1920 path->nodes[level]->start,
1921 src->root_key.objectid, level - 1, 0);
1922 BUG_ON(ret);
1923
1924 ret = btrfs_free_extent(trans, dest, old_bytenr, blocksize,
1925 0, dest->root_key.objectid, level - 1,
1926 0);
1927 BUG_ON(ret);
1928
1929 btrfs_unlock_up_safe(path, 0);
1930
1931 ret = level;
1932 break;
1933 }
1934 btrfs_tree_unlock(parent);
1935 free_extent_buffer(parent);
1936 return ret;
1937 }
1938
1939 /*
1940 * helper to find next relocated block in reloc tree
1941 */
1942 static noinline_for_stack
1943 int walk_up_reloc_tree(struct btrfs_root *root, struct btrfs_path *path,
1944 int *level)
1945 {
1946 struct extent_buffer *eb;
1947 int i;
1948 u64 last_snapshot;
1949 u32 nritems;
1950
1951 last_snapshot = btrfs_root_last_snapshot(&root->root_item);
1952
1953 for (i = 0; i < *level; i++) {
1954 free_extent_buffer(path->nodes[i]);
1955 path->nodes[i] = NULL;
1956 }
1957
1958 for (i = *level; i < BTRFS_MAX_LEVEL && path->nodes[i]; i++) {
1959 eb = path->nodes[i];
1960 nritems = btrfs_header_nritems(eb);
1961 while (path->slots[i] + 1 < nritems) {
1962 path->slots[i]++;
1963 if (btrfs_node_ptr_generation(eb, path->slots[i]) <=
1964 last_snapshot)
1965 continue;
1966
1967 *level = i;
1968 return 0;
1969 }
1970 free_extent_buffer(path->nodes[i]);
1971 path->nodes[i] = NULL;
1972 }
1973 return 1;
1974 }
1975
1976 /*
1977 * walk down reloc tree to find relocated block of lowest level
1978 */
1979 static noinline_for_stack
1980 int walk_down_reloc_tree(struct btrfs_root *root, struct btrfs_path *path,
1981 int *level)
1982 {
1983 struct btrfs_fs_info *fs_info = root->fs_info;
1984 struct extent_buffer *eb = NULL;
1985 int i;
1986 u64 bytenr;
1987 u64 ptr_gen = 0;
1988 u64 last_snapshot;
1989 u32 nritems;
1990
1991 last_snapshot = btrfs_root_last_snapshot(&root->root_item);
1992
1993 for (i = *level; i > 0; i--) {
1994 struct btrfs_key first_key;
1995
1996 eb = path->nodes[i];
1997 nritems = btrfs_header_nritems(eb);
1998 while (path->slots[i] < nritems) {
1999 ptr_gen = btrfs_node_ptr_generation(eb, path->slots[i]);
2000 if (ptr_gen > last_snapshot)
2001 break;
2002 path->slots[i]++;
2003 }
2004 if (path->slots[i] >= nritems) {
2005 if (i == *level)
2006 break;
2007 *level = i + 1;
2008 return 0;
2009 }
2010 if (i == 1) {
2011 *level = i;
2012 return 0;
2013 }
2014
2015 bytenr = btrfs_node_blockptr(eb, path->slots[i]);
2016 btrfs_node_key_to_cpu(eb, &first_key, path->slots[i]);
2017 eb = read_tree_block(fs_info, bytenr, ptr_gen, i - 1,
2018 &first_key);
2019 if (IS_ERR(eb)) {
2020 return PTR_ERR(eb);
2021 } else if (!extent_buffer_uptodate(eb)) {
2022 free_extent_buffer(eb);
2023 return -EIO;
2024 }
2025 BUG_ON(btrfs_header_level(eb) != i - 1);
2026 path->nodes[i - 1] = eb;
2027 path->slots[i - 1] = 0;
2028 }
2029 return 1;
2030 }
2031
2032 /*
2033 * invalidate extent cache for file extents whose key in range of
2034 * [min_key, max_key)
2035 */
2036 static int invalidate_extent_cache(struct btrfs_root *root,
2037 struct btrfs_key *min_key,
2038 struct btrfs_key *max_key)
2039 {
2040 struct btrfs_fs_info *fs_info = root->fs_info;
2041 struct inode *inode = NULL;
2042 u64 objectid;
2043 u64 start, end;
2044 u64 ino;
2045
2046 objectid = min_key->objectid;
2047 while (1) {
2048 cond_resched();
2049 iput(inode);
2050
2051 if (objectid > max_key->objectid)
2052 break;
2053
2054 inode = find_next_inode(root, objectid);
2055 if (!inode)
2056 break;
2057 ino = btrfs_ino(BTRFS_I(inode));
2058
2059 if (ino > max_key->objectid) {
2060 iput(inode);
2061 break;
2062 }
2063
2064 objectid = ino + 1;
2065 if (!S_ISREG(inode->i_mode))
2066 continue;
2067
2068 if (unlikely(min_key->objectid == ino)) {
2069 if (min_key->type > BTRFS_EXTENT_DATA_KEY)
2070 continue;
2071 if (min_key->type < BTRFS_EXTENT_DATA_KEY)
2072 start = 0;
2073 else {
2074 start = min_key->offset;
2075 WARN_ON(!IS_ALIGNED(start, fs_info->sectorsize));
2076 }
2077 } else {
2078 start = 0;
2079 }
2080
2081 if (unlikely(max_key->objectid == ino)) {
2082 if (max_key->type < BTRFS_EXTENT_DATA_KEY)
2083 continue;
2084 if (max_key->type > BTRFS_EXTENT_DATA_KEY) {
2085 end = (u64)-1;
2086 } else {
2087 if (max_key->offset == 0)
2088 continue;
2089 end = max_key->offset;
2090 WARN_ON(!IS_ALIGNED(end, fs_info->sectorsize));
2091 end--;
2092 }
2093 } else {
2094 end = (u64)-1;
2095 }
2096
2097 /* the lock_extent waits for readpage to complete */
2098 lock_extent(&BTRFS_I(inode)->io_tree, start, end);
2099 btrfs_drop_extent_cache(BTRFS_I(inode), start, end, 1);
2100 unlock_extent(&BTRFS_I(inode)->io_tree, start, end);
2101 }
2102 return 0;
2103 }
2104
2105 static int find_next_key(struct btrfs_path *path, int level,
2106 struct btrfs_key *key)
2107
2108 {
2109 while (level < BTRFS_MAX_LEVEL) {
2110 if (!path->nodes[level])
2111 break;
2112 if (path->slots[level] + 1 <
2113 btrfs_header_nritems(path->nodes[level])) {
2114 btrfs_node_key_to_cpu(path->nodes[level], key,
2115 path->slots[level] + 1);
2116 return 0;
2117 }
2118 level++;
2119 }
2120 return 1;
2121 }
2122
2123 /*
2124 * merge the relocated tree blocks in reloc tree with corresponding
2125 * fs tree.
2126 */
2127 static noinline_for_stack int merge_reloc_root(struct reloc_control *rc,
2128 struct btrfs_root *root)
2129 {
2130 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
2131 LIST_HEAD(inode_list);
2132 struct btrfs_key key;
2133 struct btrfs_key next_key;
2134 struct btrfs_trans_handle *trans = NULL;
2135 struct btrfs_root *reloc_root;
2136 struct btrfs_root_item *root_item;
2137 struct btrfs_path *path;
2138 struct extent_buffer *leaf;
2139 int level;
2140 int max_level;
2141 int replaced = 0;
2142 int ret;
2143 int err = 0;
2144 u32 min_reserved;
2145
2146 path = btrfs_alloc_path();
2147 if (!path)
2148 return -ENOMEM;
2149 path->reada = READA_FORWARD;
2150
2151 reloc_root = root->reloc_root;
2152 root_item = &reloc_root->root_item;
2153
2154 if (btrfs_disk_key_objectid(&root_item->drop_progress) == 0) {
2155 level = btrfs_root_level(root_item);
2156 extent_buffer_get(reloc_root->node);
2157 path->nodes[level] = reloc_root->node;
2158 path->slots[level] = 0;
2159 } else {
2160 btrfs_disk_key_to_cpu(&key, &root_item->drop_progress);
2161
2162 level = root_item->drop_level;
2163 BUG_ON(level == 0);
2164 path->lowest_level = level;
2165 ret = btrfs_search_slot(NULL, reloc_root, &key, path, 0, 0);
2166 path->lowest_level = 0;
2167 if (ret < 0) {
2168 btrfs_free_path(path);
2169 return ret;
2170 }
2171
2172 btrfs_node_key_to_cpu(path->nodes[level], &next_key,
2173 path->slots[level]);
2174 WARN_ON(memcmp(&key, &next_key, sizeof(key)));
2175
2176 btrfs_unlock_up_safe(path, 0);
2177 }
2178
2179 min_reserved = fs_info->nodesize * (BTRFS_MAX_LEVEL - 1) * 2;
2180 memset(&next_key, 0, sizeof(next_key));
2181
2182 while (1) {
2183 ret = btrfs_block_rsv_refill(root, rc->block_rsv, min_reserved,
2184 BTRFS_RESERVE_FLUSH_ALL);
2185 if (ret) {
2186 err = ret;
2187 goto out;
2188 }
2189 trans = btrfs_start_transaction(root, 0);
2190 if (IS_ERR(trans)) {
2191 err = PTR_ERR(trans);
2192 trans = NULL;
2193 goto out;
2194 }
2195 trans->block_rsv = rc->block_rsv;
2196
2197 replaced = 0;
2198 max_level = level;
2199
2200 ret = walk_down_reloc_tree(reloc_root, path, &level);
2201 if (ret < 0) {
2202 err = ret;
2203 goto out;
2204 }
2205 if (ret > 0)
2206 break;
2207
2208 if (!find_next_key(path, level, &key) &&
2209 btrfs_comp_cpu_keys(&next_key, &key) >= 0) {
2210 ret = 0;
2211 } else {
2212 ret = replace_path(trans, rc, root, reloc_root, path,
2213 &next_key, level, max_level);
2214 }
2215 if (ret < 0) {
2216 err = ret;
2217 goto out;
2218 }
2219
2220 if (ret > 0) {
2221 level = ret;
2222 btrfs_node_key_to_cpu(path->nodes[level], &key,
2223 path->slots[level]);
2224 replaced = 1;
2225 }
2226
2227 ret = walk_up_reloc_tree(reloc_root, path, &level);
2228 if (ret > 0)
2229 break;
2230
2231 BUG_ON(level == 0);
2232 /*
2233 * save the merging progress in the drop_progress.
2234 * this is OK since root refs == 1 in this case.
2235 */
2236 btrfs_node_key(path->nodes[level], &root_item->drop_progress,
2237 path->slots[level]);
2238 root_item->drop_level = level;
2239
2240 btrfs_end_transaction_throttle(trans);
2241 trans = NULL;
2242
2243 btrfs_btree_balance_dirty(fs_info);
2244
2245 if (replaced && rc->stage == UPDATE_DATA_PTRS)
2246 invalidate_extent_cache(root, &key, &next_key);
2247 }
2248
2249 /*
2250 * handle the case only one block in the fs tree need to be
2251 * relocated and the block is tree root.
2252 */
2253 leaf = btrfs_lock_root_node(root);
2254 ret = btrfs_cow_block(trans, root, leaf, NULL, 0, &leaf);
2255 btrfs_tree_unlock(leaf);
2256 free_extent_buffer(leaf);
2257 if (ret < 0)
2258 err = ret;
2259 out:
2260 btrfs_free_path(path);
2261
2262 if (err == 0) {
2263 memset(&root_item->drop_progress, 0,
2264 sizeof(root_item->drop_progress));
2265 root_item->drop_level = 0;
2266 btrfs_set_root_refs(root_item, 0);
2267 btrfs_update_reloc_root(trans, root);
2268 }
2269
2270 if (trans)
2271 btrfs_end_transaction_throttle(trans);
2272
2273 btrfs_btree_balance_dirty(fs_info);
2274
2275 if (replaced && rc->stage == UPDATE_DATA_PTRS)
2276 invalidate_extent_cache(root, &key, &next_key);
2277
2278 return err;
2279 }
2280
2281 static noinline_for_stack
2282 int prepare_to_merge(struct reloc_control *rc, int err)
2283 {
2284 struct btrfs_root *root = rc->extent_root;
2285 struct btrfs_fs_info *fs_info = root->fs_info;
2286 struct btrfs_root *reloc_root;
2287 struct btrfs_trans_handle *trans;
2288 LIST_HEAD(reloc_roots);
2289 u64 num_bytes = 0;
2290 int ret;
2291
2292 mutex_lock(&fs_info->reloc_mutex);
2293 rc->merging_rsv_size += fs_info->nodesize * (BTRFS_MAX_LEVEL - 1) * 2;
2294 rc->merging_rsv_size += rc->nodes_relocated * 2;
2295 mutex_unlock(&fs_info->reloc_mutex);
2296
2297 again:
2298 if (!err) {
2299 num_bytes = rc->merging_rsv_size;
2300 ret = btrfs_block_rsv_add(root, rc->block_rsv, num_bytes,
2301 BTRFS_RESERVE_FLUSH_ALL);
2302 if (ret)
2303 err = ret;
2304 }
2305
2306 trans = btrfs_join_transaction(rc->extent_root);
2307 if (IS_ERR(trans)) {
2308 if (!err)
2309 btrfs_block_rsv_release(fs_info, rc->block_rsv,
2310 num_bytes);
2311 return PTR_ERR(trans);
2312 }
2313
2314 if (!err) {
2315 if (num_bytes != rc->merging_rsv_size) {
2316 btrfs_end_transaction(trans);
2317 btrfs_block_rsv_release(fs_info, rc->block_rsv,
2318 num_bytes);
2319 goto again;
2320 }
2321 }
2322
2323 rc->merge_reloc_tree = 1;
2324
2325 while (!list_empty(&rc->reloc_roots)) {
2326 reloc_root = list_entry(rc->reloc_roots.next,
2327 struct btrfs_root, root_list);
2328 list_del_init(&reloc_root->root_list);
2329
2330 root = read_fs_root(fs_info, reloc_root->root_key.offset);
2331 BUG_ON(IS_ERR(root));
2332 BUG_ON(root->reloc_root != reloc_root);
2333
2334 /*
2335 * set reference count to 1, so btrfs_recover_relocation
2336 * knows it should resumes merging
2337 */
2338 if (!err)
2339 btrfs_set_root_refs(&reloc_root->root_item, 1);
2340 btrfs_update_reloc_root(trans, root);
2341
2342 list_add(&reloc_root->root_list, &reloc_roots);
2343 }
2344
2345 list_splice(&reloc_roots, &rc->reloc_roots);
2346
2347 if (!err)
2348 btrfs_commit_transaction(trans);
2349 else
2350 btrfs_end_transaction(trans);
2351 return err;
2352 }
2353
2354 static noinline_for_stack
2355 void free_reloc_roots(struct list_head *list)
2356 {
2357 struct btrfs_root *reloc_root;
2358
2359 while (!list_empty(list)) {
2360 reloc_root = list_entry(list->next, struct btrfs_root,
2361 root_list);
2362 __del_reloc_root(reloc_root);
2363 free_extent_buffer(reloc_root->node);
2364 free_extent_buffer(reloc_root->commit_root);
2365 reloc_root->node = NULL;
2366 reloc_root->commit_root = NULL;
2367 }
2368 }
2369
2370 static noinline_for_stack
2371 void merge_reloc_roots(struct reloc_control *rc)
2372 {
2373 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
2374 struct btrfs_root *root;
2375 struct btrfs_root *reloc_root;
2376 LIST_HEAD(reloc_roots);
2377 int found = 0;
2378 int ret = 0;
2379 again:
2380 root = rc->extent_root;
2381
2382 /*
2383 * this serializes us with btrfs_record_root_in_transaction,
2384 * we have to make sure nobody is in the middle of
2385 * adding their roots to the list while we are
2386 * doing this splice
2387 */
2388 mutex_lock(&fs_info->reloc_mutex);
2389 list_splice_init(&rc->reloc_roots, &reloc_roots);
2390 mutex_unlock(&fs_info->reloc_mutex);
2391
2392 while (!list_empty(&reloc_roots)) {
2393 found = 1;
2394 reloc_root = list_entry(reloc_roots.next,
2395 struct btrfs_root, root_list);
2396
2397 if (btrfs_root_refs(&reloc_root->root_item) > 0) {
2398 root = read_fs_root(fs_info,
2399 reloc_root->root_key.offset);
2400 BUG_ON(IS_ERR(root));
2401 BUG_ON(root->reloc_root != reloc_root);
2402
2403 ret = merge_reloc_root(rc, root);
2404 if (ret) {
2405 if (list_empty(&reloc_root->root_list))
2406 list_add_tail(&reloc_root->root_list,
2407 &reloc_roots);
2408 goto out;
2409 }
2410 } else {
2411 list_del_init(&reloc_root->root_list);
2412 }
2413
2414 ret = btrfs_drop_snapshot(reloc_root, rc->block_rsv, 0, 1);
2415 if (ret < 0) {
2416 if (list_empty(&reloc_root->root_list))
2417 list_add_tail(&reloc_root->root_list,
2418 &reloc_roots);
2419 goto out;
2420 }
2421 }
2422
2423 if (found) {
2424 found = 0;
2425 goto again;
2426 }
2427 out:
2428 if (ret) {
2429 btrfs_handle_fs_error(fs_info, ret, NULL);
2430 if (!list_empty(&reloc_roots))
2431 free_reloc_roots(&reloc_roots);
2432
2433 /* new reloc root may be added */
2434 mutex_lock(&fs_info->reloc_mutex);
2435 list_splice_init(&rc->reloc_roots, &reloc_roots);
2436 mutex_unlock(&fs_info->reloc_mutex);
2437 if (!list_empty(&reloc_roots))
2438 free_reloc_roots(&reloc_roots);
2439 }
2440
2441 BUG_ON(!RB_EMPTY_ROOT(&rc->reloc_root_tree.rb_root));
2442 }
2443
2444 static void free_block_list(struct rb_root *blocks)
2445 {
2446 struct tree_block *block;
2447 struct rb_node *rb_node;
2448 while ((rb_node = rb_first(blocks))) {
2449 block = rb_entry(rb_node, struct tree_block, rb_node);
2450 rb_erase(rb_node, blocks);
2451 kfree(block);
2452 }
2453 }
2454
2455 static int record_reloc_root_in_trans(struct btrfs_trans_handle *trans,
2456 struct btrfs_root *reloc_root)
2457 {
2458 struct btrfs_fs_info *fs_info = reloc_root->fs_info;
2459 struct btrfs_root *root;
2460
2461 if (reloc_root->last_trans == trans->transid)
2462 return 0;
2463
2464 root = read_fs_root(fs_info, reloc_root->root_key.offset);
2465 BUG_ON(IS_ERR(root));
2466 BUG_ON(root->reloc_root != reloc_root);
2467
2468 return btrfs_record_root_in_trans(trans, root);
2469 }
2470
2471 static noinline_for_stack
2472 struct btrfs_root *select_reloc_root(struct btrfs_trans_handle *trans,
2473 struct reloc_control *rc,
2474 struct backref_node *node,
2475 struct backref_edge *edges[])
2476 {
2477 struct backref_node *next;
2478 struct btrfs_root *root;
2479 int index = 0;
2480
2481 next = node;
2482 while (1) {
2483 cond_resched();
2484 next = walk_up_backref(next, edges, &index);
2485 root = next->root;
2486 BUG_ON(!root);
2487 BUG_ON(!test_bit(BTRFS_ROOT_REF_COWS, &root->state));
2488
2489 if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID) {
2490 record_reloc_root_in_trans(trans, root);
2491 break;
2492 }
2493
2494 btrfs_record_root_in_trans(trans, root);
2495 root = root->reloc_root;
2496
2497 if (next->new_bytenr != root->node->start) {
2498 BUG_ON(next->new_bytenr);
2499 BUG_ON(!list_empty(&next->list));
2500 next->new_bytenr = root->node->start;
2501 next->root = root;
2502 list_add_tail(&next->list,
2503 &rc->backref_cache.changed);
2504 __mark_block_processed(rc, next);
2505 break;
2506 }
2507
2508 WARN_ON(1);
2509 root = NULL;
2510 next = walk_down_backref(edges, &index);
2511 if (!next || next->level <= node->level)
2512 break;
2513 }
2514 if (!root)
2515 return NULL;
2516
2517 next = node;
2518 /* setup backref node path for btrfs_reloc_cow_block */
2519 while (1) {
2520 rc->backref_cache.path[next->level] = next;
2521 if (--index < 0)
2522 break;
2523 next = edges[index]->node[UPPER];
2524 }
2525 return root;
2526 }
2527
2528 /*
2529 * select a tree root for relocation. return NULL if the block
2530 * is reference counted. we should use do_relocation() in this
2531 * case. return a tree root pointer if the block isn't reference
2532 * counted. return -ENOENT if the block is root of reloc tree.
2533 */
2534 static noinline_for_stack
2535 struct btrfs_root *select_one_root(struct backref_node *node)
2536 {
2537 struct backref_node *next;
2538 struct btrfs_root *root;
2539 struct btrfs_root *fs_root = NULL;
2540 struct backref_edge *edges[BTRFS_MAX_LEVEL - 1];
2541 int index = 0;
2542
2543 next = node;
2544 while (1) {
2545 cond_resched();
2546 next = walk_up_backref(next, edges, &index);
2547 root = next->root;
2548 BUG_ON(!root);
2549
2550 /* no other choice for non-references counted tree */
2551 if (!test_bit(BTRFS_ROOT_REF_COWS, &root->state))
2552 return root;
2553
2554 if (root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID)
2555 fs_root = root;
2556
2557 if (next != node)
2558 return NULL;
2559
2560 next = walk_down_backref(edges, &index);
2561 if (!next || next->level <= node->level)
2562 break;
2563 }
2564
2565 if (!fs_root)
2566 return ERR_PTR(-ENOENT);
2567 return fs_root;
2568 }
2569
2570 static noinline_for_stack
2571 u64 calcu_metadata_size(struct reloc_control *rc,
2572 struct backref_node *node, int reserve)
2573 {
2574 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
2575 struct backref_node *next = node;
2576 struct backref_edge *edge;
2577 struct backref_edge *edges[BTRFS_MAX_LEVEL - 1];
2578 u64 num_bytes = 0;
2579 int index = 0;
2580
2581 BUG_ON(reserve && node->processed);
2582
2583 while (next) {
2584 cond_resched();
2585 while (1) {
2586 if (next->processed && (reserve || next != node))
2587 break;
2588
2589 num_bytes += fs_info->nodesize;
2590
2591 if (list_empty(&next->upper))
2592 break;
2593
2594 edge = list_entry(next->upper.next,
2595 struct backref_edge, list[LOWER]);
2596 edges[index++] = edge;
2597 next = edge->node[UPPER];
2598 }
2599 next = walk_down_backref(edges, &index);
2600 }
2601 return num_bytes;
2602 }
2603
2604 static int reserve_metadata_space(struct btrfs_trans_handle *trans,
2605 struct reloc_control *rc,
2606 struct backref_node *node)
2607 {
2608 struct btrfs_root *root = rc->extent_root;
2609 struct btrfs_fs_info *fs_info = root->fs_info;
2610 u64 num_bytes;
2611 int ret;
2612 u64 tmp;
2613
2614 num_bytes = calcu_metadata_size(rc, node, 1) * 2;
2615
2616 trans->block_rsv = rc->block_rsv;
2617 rc->reserved_bytes += num_bytes;
2618
2619 /*
2620 * We are under a transaction here so we can only do limited flushing.
2621 * If we get an enospc just kick back -EAGAIN so we know to drop the
2622 * transaction and try to refill when we can flush all the things.
2623 */
2624 ret = btrfs_block_rsv_refill(root, rc->block_rsv, num_bytes,
2625 BTRFS_RESERVE_FLUSH_LIMIT);
2626 if (ret) {
2627 tmp = fs_info->nodesize * RELOCATION_RESERVED_NODES;
2628 while (tmp <= rc->reserved_bytes)
2629 tmp <<= 1;
2630 /*
2631 * only one thread can access block_rsv at this point,
2632 * so we don't need hold lock to protect block_rsv.
2633 * we expand more reservation size here to allow enough
2634 * space for relocation and we will return eailer in
2635 * enospc case.
2636 */
2637 rc->block_rsv->size = tmp + fs_info->nodesize *
2638 RELOCATION_RESERVED_NODES;
2639 return -EAGAIN;
2640 }
2641
2642 return 0;
2643 }
2644
2645 /*
2646 * relocate a block tree, and then update pointers in upper level
2647 * blocks that reference the block to point to the new location.
2648 *
2649 * if called by link_to_upper, the block has already been relocated.
2650 * in that case this function just updates pointers.
2651 */
2652 static int do_relocation(struct btrfs_trans_handle *trans,
2653 struct reloc_control *rc,
2654 struct backref_node *node,
2655 struct btrfs_key *key,
2656 struct btrfs_path *path, int lowest)
2657 {
2658 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
2659 struct backref_node *upper;
2660 struct backref_edge *edge;
2661 struct backref_edge *edges[BTRFS_MAX_LEVEL - 1];
2662 struct btrfs_root *root;
2663 struct extent_buffer *eb;
2664 u32 blocksize;
2665 u64 bytenr;
2666 u64 generation;
2667 int slot;
2668 int ret;
2669 int err = 0;
2670
2671 BUG_ON(lowest && node->eb);
2672
2673 path->lowest_level = node->level + 1;
2674 rc->backref_cache.path[node->level] = node;
2675 list_for_each_entry(edge, &node->upper, list[LOWER]) {
2676 struct btrfs_key first_key;
2677
2678 cond_resched();
2679
2680 upper = edge->node[UPPER];
2681 root = select_reloc_root(trans, rc, upper, edges);
2682 BUG_ON(!root);
2683
2684 if (upper->eb && !upper->locked) {
2685 if (!lowest) {
2686 ret = btrfs_bin_search(upper->eb, key,
2687 upper->level, &slot);
2688 BUG_ON(ret);
2689 bytenr = btrfs_node_blockptr(upper->eb, slot);
2690 if (node->eb->start == bytenr)
2691 goto next;
2692 }
2693 drop_node_buffer(upper);
2694 }
2695
2696 if (!upper->eb) {
2697 ret = btrfs_search_slot(trans, root, key, path, 0, 1);
2698 if (ret) {
2699 if (ret < 0)
2700 err = ret;
2701 else
2702 err = -ENOENT;
2703
2704 btrfs_release_path(path);
2705 break;
2706 }
2707
2708 if (!upper->eb) {
2709 upper->eb = path->nodes[upper->level];
2710 path->nodes[upper->level] = NULL;
2711 } else {
2712 BUG_ON(upper->eb != path->nodes[upper->level]);
2713 }
2714
2715 upper->locked = 1;
2716 path->locks[upper->level] = 0;
2717
2718 slot = path->slots[upper->level];
2719 btrfs_release_path(path);
2720 } else {
2721 ret = btrfs_bin_search(upper->eb, key, upper->level,
2722 &slot);
2723 BUG_ON(ret);
2724 }
2725
2726 bytenr = btrfs_node_blockptr(upper->eb, slot);
2727 if (lowest) {
2728 if (bytenr != node->bytenr) {
2729 btrfs_err(root->fs_info,
2730 "lowest leaf/node mismatch: bytenr %llu node->bytenr %llu slot %d upper %llu",
2731 bytenr, node->bytenr, slot,
2732 upper->eb->start);
2733 err = -EIO;
2734 goto next;
2735 }
2736 } else {
2737 if (node->eb->start == bytenr)
2738 goto next;
2739 }
2740
2741 blocksize = root->fs_info->nodesize;
2742 generation = btrfs_node_ptr_generation(upper->eb, slot);
2743 btrfs_node_key_to_cpu(upper->eb, &first_key, slot);
2744 eb = read_tree_block(fs_info, bytenr, generation,
2745 upper->level - 1, &first_key);
2746 if (IS_ERR(eb)) {
2747 err = PTR_ERR(eb);
2748 goto next;
2749 } else if (!extent_buffer_uptodate(eb)) {
2750 free_extent_buffer(eb);
2751 err = -EIO;
2752 goto next;
2753 }
2754 btrfs_tree_lock(eb);
2755 btrfs_set_lock_blocking(eb);
2756
2757 if (!node->eb) {
2758 ret = btrfs_cow_block(trans, root, eb, upper->eb,
2759 slot, &eb);
2760 btrfs_tree_unlock(eb);
2761 free_extent_buffer(eb);
2762 if (ret < 0) {
2763 err = ret;
2764 goto next;
2765 }
2766 BUG_ON(node->eb != eb);
2767 } else {
2768 btrfs_set_node_blockptr(upper->eb, slot,
2769 node->eb->start);
2770 btrfs_set_node_ptr_generation(upper->eb, slot,
2771 trans->transid);
2772 btrfs_mark_buffer_dirty(upper->eb);
2773
2774 ret = btrfs_inc_extent_ref(trans, root,
2775 node->eb->start, blocksize,
2776 upper->eb->start,
2777 btrfs_header_owner(upper->eb),
2778 node->level, 0);
2779 BUG_ON(ret);
2780
2781 ret = btrfs_drop_subtree(trans, root, eb, upper->eb);
2782 BUG_ON(ret);
2783 }
2784 next:
2785 if (!upper->pending)
2786 drop_node_buffer(upper);
2787 else
2788 unlock_node_buffer(upper);
2789 if (err)
2790 break;
2791 }
2792
2793 if (!err && node->pending) {
2794 drop_node_buffer(node);
2795 list_move_tail(&node->list, &rc->backref_cache.changed);
2796 node->pending = 0;
2797 }
2798
2799 path->lowest_level = 0;
2800 BUG_ON(err == -ENOSPC);
2801 return err;
2802 }
2803
2804 static int link_to_upper(struct btrfs_trans_handle *trans,
2805 struct reloc_control *rc,
2806 struct backref_node *node,
2807 struct btrfs_path *path)
2808 {
2809 struct btrfs_key key;
2810
2811 btrfs_node_key_to_cpu(node->eb, &key, 0);
2812 return do_relocation(trans, rc, node, &key, path, 0);
2813 }
2814
2815 static int finish_pending_nodes(struct btrfs_trans_handle *trans,
2816 struct reloc_control *rc,
2817 struct btrfs_path *path, int err)
2818 {
2819 LIST_HEAD(list);
2820 struct backref_cache *cache = &rc->backref_cache;
2821 struct backref_node *node;
2822 int level;
2823 int ret;
2824
2825 for (level = 0; level < BTRFS_MAX_LEVEL; level++) {
2826 while (!list_empty(&cache->pending[level])) {
2827 node = list_entry(cache->pending[level].next,
2828 struct backref_node, list);
2829 list_move_tail(&node->list, &list);
2830 BUG_ON(!node->pending);
2831
2832 if (!err) {
2833 ret = link_to_upper(trans, rc, node, path);
2834 if (ret < 0)
2835 err = ret;
2836 }
2837 }
2838 list_splice_init(&list, &cache->pending[level]);
2839 }
2840 return err;
2841 }
2842
2843 static void mark_block_processed(struct reloc_control *rc,
2844 u64 bytenr, u32 blocksize)
2845 {
2846 set_extent_bits(&rc->processed_blocks, bytenr, bytenr + blocksize - 1,
2847 EXTENT_DIRTY);
2848 }
2849
2850 static void __mark_block_processed(struct reloc_control *rc,
2851 struct backref_node *node)
2852 {
2853 u32 blocksize;
2854 if (node->level == 0 ||
2855 in_block_group(node->bytenr, rc->block_group)) {
2856 blocksize = rc->extent_root->fs_info->nodesize;
2857 mark_block_processed(rc, node->bytenr, blocksize);
2858 }
2859 node->processed = 1;
2860 }
2861
2862 /*
2863 * mark a block and all blocks directly/indirectly reference the block
2864 * as processed.
2865 */
2866 static void update_processed_blocks(struct reloc_control *rc,
2867 struct backref_node *node)
2868 {
2869 struct backref_node *next = node;
2870 struct backref_edge *edge;
2871 struct backref_edge *edges[BTRFS_MAX_LEVEL - 1];
2872 int index = 0;
2873
2874 while (next) {
2875 cond_resched();
2876 while (1) {
2877 if (next->processed)
2878 break;
2879
2880 __mark_block_processed(rc, next);
2881
2882 if (list_empty(&next->upper))
2883 break;
2884
2885 edge = list_entry(next->upper.next,
2886 struct backref_edge, list[LOWER]);
2887 edges[index++] = edge;
2888 next = edge->node[UPPER];
2889 }
2890 next = walk_down_backref(edges, &index);
2891 }
2892 }
2893
2894 static int tree_block_processed(u64 bytenr, struct reloc_control *rc)
2895 {
2896 u32 blocksize = rc->extent_root->fs_info->nodesize;
2897
2898 if (test_range_bit(&rc->processed_blocks, bytenr,
2899 bytenr + blocksize - 1, EXTENT_DIRTY, 1, NULL))
2900 return 1;
2901 return 0;
2902 }
2903
2904 static int get_tree_block_key(struct btrfs_fs_info *fs_info,
2905 struct tree_block *block)
2906 {
2907 struct extent_buffer *eb;
2908
2909 BUG_ON(block->key_ready);
2910 eb = read_tree_block(fs_info, block->bytenr, block->key.offset,
2911 block->level, NULL);
2912 if (IS_ERR(eb)) {
2913 return PTR_ERR(eb);
2914 } else if (!extent_buffer_uptodate(eb)) {
2915 free_extent_buffer(eb);
2916 return -EIO;
2917 }
2918 if (block->level == 0)
2919 btrfs_item_key_to_cpu(eb, &block->key, 0);
2920 else
2921 btrfs_node_key_to_cpu(eb, &block->key, 0);
2922 free_extent_buffer(eb);
2923 block->key_ready = 1;
2924 return 0;
2925 }
2926
2927 /*
2928 * helper function to relocate a tree block
2929 */
2930 static int relocate_tree_block(struct btrfs_trans_handle *trans,
2931 struct reloc_control *rc,
2932 struct backref_node *node,
2933 struct btrfs_key *key,
2934 struct btrfs_path *path)
2935 {
2936 struct btrfs_root *root;
2937 int ret = 0;
2938
2939 if (!node)
2940 return 0;
2941
2942 BUG_ON(node->processed);
2943 root = select_one_root(node);
2944 if (root == ERR_PTR(-ENOENT)) {
2945 update_processed_blocks(rc, node);
2946 goto out;
2947 }
2948
2949 if (!root || test_bit(BTRFS_ROOT_REF_COWS, &root->state)) {
2950 ret = reserve_metadata_space(trans, rc, node);
2951 if (ret)
2952 goto out;
2953 }
2954
2955 if (root) {
2956 if (test_bit(BTRFS_ROOT_REF_COWS, &root->state)) {
2957 BUG_ON(node->new_bytenr);
2958 BUG_ON(!list_empty(&node->list));
2959 btrfs_record_root_in_trans(trans, root);
2960 root = root->reloc_root;
2961 node->new_bytenr = root->node->start;
2962 node->root = root;
2963 list_add_tail(&node->list, &rc->backref_cache.changed);
2964 } else {
2965 path->lowest_level = node->level;
2966 ret = btrfs_search_slot(trans, root, key, path, 0, 1);
2967 btrfs_release_path(path);
2968 if (ret > 0)
2969 ret = 0;
2970 }
2971 if (!ret)
2972 update_processed_blocks(rc, node);
2973 } else {
2974 ret = do_relocation(trans, rc, node, key, path, 1);
2975 }
2976 out:
2977 if (ret || node->level == 0 || node->cowonly)
2978 remove_backref_node(&rc->backref_cache, node);
2979 return ret;
2980 }
2981
2982 /*
2983 * relocate a list of blocks
2984 */
2985 static noinline_for_stack
2986 int relocate_tree_blocks(struct btrfs_trans_handle *trans,
2987 struct reloc_control *rc, struct rb_root *blocks)
2988 {
2989 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
2990 struct backref_node *node;
2991 struct btrfs_path *path;
2992 struct tree_block *block;
2993 struct tree_block *next;
2994 int ret;
2995 int err = 0;
2996
2997 path = btrfs_alloc_path();
2998 if (!path) {
2999 err = -ENOMEM;
3000 goto out_free_blocks;
3001 }
3002
3003 /* Kick in readahead for tree blocks with missing keys */
3004 rbtree_postorder_for_each_entry_safe(block, next, blocks, rb_node) {
3005 if (!block->key_ready)
3006 readahead_tree_block(fs_info, block->bytenr);
3007 }
3008
3009 /* Get first keys */
3010 rbtree_postorder_for_each_entry_safe(block, next, blocks, rb_node) {
3011 if (!block->key_ready) {
3012 err = get_tree_block_key(fs_info, block);
3013 if (err)
3014 goto out_free_path;
3015 }
3016 }
3017
3018 /* Do tree relocation */
3019 rbtree_postorder_for_each_entry_safe(block, next, blocks, rb_node) {
3020 node = build_backref_tree(rc, &block->key,
3021 block->level, block->bytenr);
3022 if (IS_ERR(node)) {
3023 err = PTR_ERR(node);
3024 goto out;
3025 }
3026
3027 ret = relocate_tree_block(trans, rc, node, &block->key,
3028 path);
3029 if (ret < 0) {
3030 if (ret != -EAGAIN || &block->rb_node == rb_first(blocks))
3031 err = ret;
3032 goto out;
3033 }
3034 }
3035 out:
3036 err = finish_pending_nodes(trans, rc, path, err);
3037
3038 out_free_path:
3039 btrfs_free_path(path);
3040 out_free_blocks:
3041 free_block_list(blocks);
3042 return err;
3043 }
3044
3045 static noinline_for_stack
3046 int prealloc_file_extent_cluster(struct inode *inode,
3047 struct file_extent_cluster *cluster)
3048 {
3049 u64 alloc_hint = 0;
3050 u64 start;
3051 u64 end;
3052 u64 offset = BTRFS_I(inode)->index_cnt;
3053 u64 num_bytes;
3054 int nr = 0;
3055 int ret = 0;
3056 u64 prealloc_start = cluster->start - offset;
3057 u64 prealloc_end = cluster->end - offset;
3058 u64 cur_offset;
3059 struct extent_changeset *data_reserved = NULL;
3060
3061 BUG_ON(cluster->start != cluster->boundary[0]);
3062 inode_lock(inode);
3063
3064 ret = btrfs_check_data_free_space(inode, &data_reserved, prealloc_start,
3065 prealloc_end + 1 - prealloc_start);
3066 if (ret)
3067 goto out;
3068
3069 cur_offset = prealloc_start;
3070 while (nr < cluster->nr) {
3071 start = cluster->boundary[nr] - offset;
3072 if (nr + 1 < cluster->nr)
3073 end = cluster->boundary[nr + 1] - 1 - offset;
3074 else
3075 end = cluster->end - offset;
3076
3077 lock_extent(&BTRFS_I(inode)->io_tree, start, end);
3078 num_bytes = end + 1 - start;
3079 if (cur_offset < start)
3080 btrfs_free_reserved_data_space(inode, data_reserved,
3081 cur_offset, start - cur_offset);
3082 ret = btrfs_prealloc_file_range(inode, 0, start,
3083 num_bytes, num_bytes,
3084 end + 1, &alloc_hint);
3085 cur_offset = end + 1;
3086 unlock_extent(&BTRFS_I(inode)->io_tree, start, end);
3087 if (ret)
3088 break;
3089 nr++;
3090 }
3091 if (cur_offset < prealloc_end)
3092 btrfs_free_reserved_data_space(inode, data_reserved,
3093 cur_offset, prealloc_end + 1 - cur_offset);
3094 out:
3095 inode_unlock(inode);
3096 extent_changeset_free(data_reserved);
3097 return ret;
3098 }
3099
3100 static noinline_for_stack
3101 int setup_extent_mapping(struct inode *inode, u64 start, u64 end,
3102 u64 block_start)
3103 {
3104 struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
3105 struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
3106 struct extent_map *em;
3107 int ret = 0;
3108
3109 em = alloc_extent_map();
3110 if (!em)
3111 return -ENOMEM;
3112
3113 em->start = start;
3114 em->len = end + 1 - start;
3115 em->block_len = em->len;
3116 em->block_start = block_start;
3117 em->bdev = fs_info->fs_devices->latest_bdev;
3118 set_bit(EXTENT_FLAG_PINNED, &em->flags);
3119
3120 lock_extent(&BTRFS_I(inode)->io_tree, start, end);
3121 while (1) {
3122 write_lock(&em_tree->lock);
3123 ret = add_extent_mapping(em_tree, em, 0);
3124 write_unlock(&em_tree->lock);
3125 if (ret != -EEXIST) {
3126 free_extent_map(em);
3127 break;
3128 }
3129 btrfs_drop_extent_cache(BTRFS_I(inode), start, end, 0);
3130 }
3131 unlock_extent(&BTRFS_I(inode)->io_tree, start, end);
3132 return ret;
3133 }
3134
3135 static int relocate_file_extent_cluster(struct inode *inode,
3136 struct file_extent_cluster *cluster)
3137 {
3138 struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
3139 u64 page_start;
3140 u64 page_end;
3141 u64 offset = BTRFS_I(inode)->index_cnt;
3142 unsigned long index;
3143 unsigned long last_index;
3144 struct page *page;
3145 struct file_ra_state *ra;
3146 gfp_t mask = btrfs_alloc_write_mask(inode->i_mapping);
3147 int nr = 0;
3148 int ret = 0;
3149
3150 if (!cluster->nr)
3151 return 0;
3152
3153 ra = kzalloc(sizeof(*ra), GFP_NOFS);
3154 if (!ra)
3155 return -ENOMEM;
3156
3157 ret = prealloc_file_extent_cluster(inode, cluster);
3158 if (ret)
3159 goto out;
3160
3161 file_ra_state_init(ra, inode->i_mapping);
3162
3163 ret = setup_extent_mapping(inode, cluster->start - offset,
3164 cluster->end - offset, cluster->start);
3165 if (ret)
3166 goto out;
3167
3168 index = (cluster->start - offset) >> PAGE_SHIFT;
3169 last_index = (cluster->end - offset) >> PAGE_SHIFT;
3170 while (index <= last_index) {
3171 ret = btrfs_delalloc_reserve_metadata(BTRFS_I(inode),
3172 PAGE_SIZE);
3173 if (ret)
3174 goto out;
3175
3176 page = find_lock_page(inode->i_mapping, index);
3177 if (!page) {
3178 page_cache_sync_readahead(inode->i_mapping,
3179 ra, NULL, index,
3180 last_index + 1 - index);
3181 page = find_or_create_page(inode->i_mapping, index,
3182 mask);
3183 if (!page) {
3184 btrfs_delalloc_release_metadata(BTRFS_I(inode),
3185 PAGE_SIZE, true);
3186 ret = -ENOMEM;
3187 goto out;
3188 }
3189 }
3190
3191 if (PageReadahead(page)) {
3192 page_cache_async_readahead(inode->i_mapping,
3193 ra, NULL, page, index,
3194 last_index + 1 - index);
3195 }
3196
3197 if (!PageUptodate(page)) {
3198 btrfs_readpage(NULL, page);
3199 lock_page(page);
3200 if (!PageUptodate(page)) {
3201 unlock_page(page);
3202 put_page(page);
3203 btrfs_delalloc_release_metadata(BTRFS_I(inode),
3204 PAGE_SIZE, true);
3205 btrfs_delalloc_release_extents(BTRFS_I(inode),
3206 PAGE_SIZE, true);
3207 ret = -EIO;
3208 goto out;
3209 }
3210 }
3211
3212 page_start = page_offset(page);
3213 page_end = page_start + PAGE_SIZE - 1;
3214
3215 lock_extent(&BTRFS_I(inode)->io_tree, page_start, page_end);
3216
3217 set_page_extent_mapped(page);
3218
3219 if (nr < cluster->nr &&
3220 page_start + offset == cluster->boundary[nr]) {
3221 set_extent_bits(&BTRFS_I(inode)->io_tree,
3222 page_start, page_end,
3223 EXTENT_BOUNDARY);
3224 nr++;
3225 }
3226
3227 ret = btrfs_set_extent_delalloc(inode, page_start, page_end, 0,
3228 NULL, 0);
3229 if (ret) {
3230 unlock_page(page);
3231 put_page(page);
3232 btrfs_delalloc_release_metadata(BTRFS_I(inode),
3233 PAGE_SIZE, true);
3234 btrfs_delalloc_release_extents(BTRFS_I(inode),
3235 PAGE_SIZE, true);
3236
3237 clear_extent_bits(&BTRFS_I(inode)->io_tree,
3238 page_start, page_end,
3239 EXTENT_LOCKED | EXTENT_BOUNDARY);
3240 goto out;
3241
3242 }
3243 set_page_dirty(page);
3244
3245 unlock_extent(&BTRFS_I(inode)->io_tree,
3246 page_start, page_end);
3247 unlock_page(page);
3248 put_page(page);
3249
3250 index++;
3251 btrfs_delalloc_release_extents(BTRFS_I(inode), PAGE_SIZE,
3252 false);
3253 balance_dirty_pages_ratelimited(inode->i_mapping);
3254 btrfs_throttle(fs_info);
3255 }
3256 WARN_ON(nr != cluster->nr);
3257 out:
3258 kfree(ra);
3259 return ret;
3260 }
3261
3262 static noinline_for_stack
3263 int relocate_data_extent(struct inode *inode, struct btrfs_key *extent_key,
3264 struct file_extent_cluster *cluster)
3265 {
3266 int ret;
3267
3268 if (cluster->nr > 0 && extent_key->objectid != cluster->end + 1) {
3269 ret = relocate_file_extent_cluster(inode, cluster);
3270 if (ret)
3271 return ret;
3272 cluster->nr = 0;
3273 }
3274
3275 if (!cluster->nr)
3276 cluster->start = extent_key->objectid;
3277 else
3278 BUG_ON(cluster->nr >= MAX_EXTENTS);
3279 cluster->end = extent_key->objectid + extent_key->offset - 1;
3280 cluster->boundary[cluster->nr] = extent_key->objectid;
3281 cluster->nr++;
3282
3283 if (cluster->nr >= MAX_EXTENTS) {
3284 ret = relocate_file_extent_cluster(inode, cluster);
3285 if (ret)
3286 return ret;
3287 cluster->nr = 0;
3288 }
3289 return 0;
3290 }
3291
3292 /*
3293 * helper to add a tree block to the list.
3294 * the major work is getting the generation and level of the block
3295 */
3296 static int add_tree_block(struct reloc_control *rc,
3297 struct btrfs_key *extent_key,
3298 struct btrfs_path *path,
3299 struct rb_root *blocks)
3300 {
3301 struct extent_buffer *eb;
3302 struct btrfs_extent_item *ei;
3303 struct btrfs_tree_block_info *bi;
3304 struct tree_block *block;
3305 struct rb_node *rb_node;
3306 u32 item_size;
3307 int level = -1;
3308 u64 generation;
3309
3310 eb = path->nodes[0];
3311 item_size = btrfs_item_size_nr(eb, path->slots[0]);
3312
3313 if (extent_key->type == BTRFS_METADATA_ITEM_KEY ||
3314 item_size >= sizeof(*ei) + sizeof(*bi)) {
3315 ei = btrfs_item_ptr(eb, path->slots[0],
3316 struct btrfs_extent_item);
3317 if (extent_key->type == BTRFS_EXTENT_ITEM_KEY) {
3318 bi = (struct btrfs_tree_block_info *)(ei + 1);
3319 level = btrfs_tree_block_level(eb, bi);
3320 } else {
3321 level = (int)extent_key->offset;
3322 }
3323 generation = btrfs_extent_generation(eb, ei);
3324 } else if (unlikely(item_size == sizeof(struct btrfs_extent_item_v0))) {
3325 btrfs_print_v0_err(eb->fs_info);
3326 btrfs_handle_fs_error(eb->fs_info, -EINVAL, NULL);
3327 return -EINVAL;
3328 } else {
3329 BUG();
3330 }
3331
3332 btrfs_release_path(path);
3333
3334 BUG_ON(level == -1);
3335
3336 block = kmalloc(sizeof(*block), GFP_NOFS);
3337 if (!block)
3338 return -ENOMEM;
3339
3340 block->bytenr = extent_key->objectid;
3341 block->key.objectid = rc->extent_root->fs_info->nodesize;
3342 block->key.offset = generation;
3343 block->level = level;
3344 block->key_ready = 0;
3345
3346 rb_node = tree_insert(blocks, block->bytenr, &block->rb_node);
3347 if (rb_node)
3348 backref_tree_panic(rb_node, -EEXIST, block->bytenr);
3349
3350 return 0;
3351 }
3352
3353 /*
3354 * helper to add tree blocks for backref of type BTRFS_SHARED_DATA_REF_KEY
3355 */
3356 static int __add_tree_block(struct reloc_control *rc,
3357 u64 bytenr, u32 blocksize,
3358 struct rb_root *blocks)
3359 {
3360 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
3361 struct btrfs_path *path;
3362 struct btrfs_key key;
3363 int ret;
3364 bool skinny = btrfs_fs_incompat(fs_info, SKINNY_METADATA);
3365
3366 if (tree_block_processed(bytenr, rc))
3367 return 0;
3368
3369 if (tree_search(blocks, bytenr))
3370 return 0;
3371
3372 path = btrfs_alloc_path();
3373 if (!path)
3374 return -ENOMEM;
3375 again:
3376 key.objectid = bytenr;
3377 if (skinny) {
3378 key.type = BTRFS_METADATA_ITEM_KEY;
3379 key.offset = (u64)-1;
3380 } else {
3381 key.type = BTRFS_EXTENT_ITEM_KEY;
3382 key.offset = blocksize;
3383 }
3384
3385 path->search_commit_root = 1;
3386 path->skip_locking = 1;
3387 ret = btrfs_search_slot(NULL, rc->extent_root, &key, path, 0, 0);
3388 if (ret < 0)
3389 goto out;
3390
3391 if (ret > 0 && skinny) {
3392 if (path->slots[0]) {
3393 path->slots[0]--;
3394 btrfs_item_key_to_cpu(path->nodes[0], &key,
3395 path->slots[0]);
3396 if (key.objectid == bytenr &&
3397 (key.type == BTRFS_METADATA_ITEM_KEY ||
3398 (key.type == BTRFS_EXTENT_ITEM_KEY &&
3399 key.offset == blocksize)))
3400 ret = 0;
3401 }
3402
3403 if (ret) {
3404 skinny = false;
3405 btrfs_release_path(path);
3406 goto again;
3407 }
3408 }
3409 if (ret) {
3410 ASSERT(ret == 1);
3411 btrfs_print_leaf(path->nodes[0]);
3412 btrfs_err(fs_info,
3413 "tree block extent item (%llu) is not found in extent tree",
3414 bytenr);
3415 WARN_ON(1);
3416 ret = -EINVAL;
3417 goto out;
3418 }
3419
3420 ret = add_tree_block(rc, &key, path, blocks);
3421 out:
3422 btrfs_free_path(path);
3423 return ret;
3424 }
3425
3426 /*
3427 * helper to check if the block use full backrefs for pointers in it
3428 */
3429 static int block_use_full_backref(struct reloc_control *rc,
3430 struct extent_buffer *eb)
3431 {
3432 u64 flags;
3433 int ret;
3434
3435 if (btrfs_header_flag(eb, BTRFS_HEADER_FLAG_RELOC) ||
3436 btrfs_header_backref_rev(eb) < BTRFS_MIXED_BACKREF_REV)
3437 return 1;
3438
3439 ret = btrfs_lookup_extent_info(NULL, rc->extent_root->fs_info,
3440 eb->start, btrfs_header_level(eb), 1,
3441 NULL, &flags);
3442 BUG_ON(ret);
3443
3444 if (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF)
3445 ret = 1;
3446 else
3447 ret = 0;
3448 return ret;
3449 }
3450
3451 static int delete_block_group_cache(struct btrfs_fs_info *fs_info,
3452 struct btrfs_block_group_cache *block_group,
3453 struct inode *inode,
3454 u64 ino)
3455 {
3456 struct btrfs_key key;
3457 struct btrfs_root *root = fs_info->tree_root;
3458 struct btrfs_trans_handle *trans;
3459 int ret = 0;
3460
3461 if (inode)
3462 goto truncate;
3463
3464 key.objectid = ino;
3465 key.type = BTRFS_INODE_ITEM_KEY;
3466 key.offset = 0;
3467
3468 inode = btrfs_iget(fs_info->sb, &key, root, NULL);
3469 if (IS_ERR(inode))
3470 return -ENOENT;
3471
3472 truncate:
3473 ret = btrfs_check_trunc_cache_free_space(fs_info,
3474 &fs_info->global_block_rsv);
3475 if (ret)
3476 goto out;
3477
3478 trans = btrfs_join_transaction(root);
3479 if (IS_ERR(trans)) {
3480 ret = PTR_ERR(trans);
3481 goto out;
3482 }
3483
3484 ret = btrfs_truncate_free_space_cache(trans, block_group, inode);
3485
3486 btrfs_end_transaction(trans);
3487 btrfs_btree_balance_dirty(fs_info);
3488 out:
3489 iput(inode);
3490 return ret;
3491 }
3492
3493 /*
3494 * helper to add tree blocks for backref of type BTRFS_EXTENT_DATA_REF_KEY
3495 * this function scans fs tree to find blocks reference the data extent
3496 */
3497 static int find_data_references(struct reloc_control *rc,
3498 struct btrfs_key *extent_key,
3499 struct extent_buffer *leaf,
3500 struct btrfs_extent_data_ref *ref,
3501 struct rb_root *blocks)
3502 {
3503 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
3504 struct btrfs_path *path;
3505 struct tree_block *block;
3506 struct btrfs_root *root;
3507 struct btrfs_file_extent_item *fi;
3508 struct rb_node *rb_node;
3509 struct btrfs_key key;
3510 u64 ref_root;
3511 u64 ref_objectid;
3512 u64 ref_offset;
3513 u32 ref_count;
3514 u32 nritems;
3515 int err = 0;
3516 int added = 0;
3517 int counted;
3518 int ret;
3519
3520 ref_root = btrfs_extent_data_ref_root(leaf, ref);
3521 ref_objectid = btrfs_extent_data_ref_objectid(leaf, ref);
3522 ref_offset = btrfs_extent_data_ref_offset(leaf, ref);
3523 ref_count = btrfs_extent_data_ref_count(leaf, ref);
3524
3525 /*
3526 * This is an extent belonging to the free space cache, lets just delete
3527 * it and redo the search.
3528 */
3529 if (ref_root == BTRFS_ROOT_TREE_OBJECTID) {
3530 ret = delete_block_group_cache(fs_info, rc->block_group,
3531 NULL, ref_objectid);
3532 if (ret != -ENOENT)
3533 return ret;
3534 ret = 0;
3535 }
3536
3537 path = btrfs_alloc_path();
3538 if (!path)
3539 return -ENOMEM;
3540 path->reada = READA_FORWARD;
3541
3542 root = read_fs_root(fs_info, ref_root);
3543 if (IS_ERR(root)) {
3544 err = PTR_ERR(root);
3545 goto out;
3546 }
3547
3548 key.objectid = ref_objectid;
3549 key.type = BTRFS_EXTENT_DATA_KEY;
3550 if (ref_offset > ((u64)-1 << 32))
3551 key.offset = 0;
3552 else
3553 key.offset = ref_offset;
3554
3555 path->search_commit_root = 1;
3556 path->skip_locking = 1;
3557 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
3558 if (ret < 0) {
3559 err = ret;
3560 goto out;
3561 }
3562
3563 leaf = path->nodes[0];
3564 nritems = btrfs_header_nritems(leaf);
3565 /*
3566 * the references in tree blocks that use full backrefs
3567 * are not counted in
3568 */
3569 if (block_use_full_backref(rc, leaf))
3570 counted = 0;
3571 else
3572 counted = 1;
3573 rb_node = tree_search(blocks, leaf->start);
3574 if (rb_node) {
3575 if (counted)
3576 added = 1;
3577 else
3578 path->slots[0] = nritems;
3579 }
3580
3581 while (ref_count > 0) {
3582 while (path->slots[0] >= nritems) {
3583 ret = btrfs_next_leaf(root, path);
3584 if (ret < 0) {
3585 err = ret;
3586 goto out;
3587 }
3588 if (WARN_ON(ret > 0))
3589 goto out;
3590
3591 leaf = path->nodes[0];
3592 nritems = btrfs_header_nritems(leaf);
3593 added = 0;
3594
3595 if (block_use_full_backref(rc, leaf))
3596 counted = 0;
3597 else
3598 counted = 1;
3599 rb_node = tree_search(blocks, leaf->start);
3600 if (rb_node) {
3601 if (counted)
3602 added = 1;
3603 else
3604 path->slots[0] = nritems;
3605 }
3606 }
3607
3608 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
3609 if (WARN_ON(key.objectid != ref_objectid ||
3610 key.type != BTRFS_EXTENT_DATA_KEY))
3611 break;
3612
3613 fi = btrfs_item_ptr(leaf, path->slots[0],
3614 struct btrfs_file_extent_item);
3615
3616 if (btrfs_file_extent_type(leaf, fi) ==
3617 BTRFS_FILE_EXTENT_INLINE)
3618 goto next;
3619
3620 if (btrfs_file_extent_disk_bytenr(leaf, fi) !=
3621 extent_key->objectid)
3622 goto next;
3623
3624 key.offset -= btrfs_file_extent_offset(leaf, fi);
3625 if (key.offset != ref_offset)
3626 goto next;
3627
3628 if (counted)
3629 ref_count--;
3630 if (added)
3631 goto next;
3632
3633 if (!tree_block_processed(leaf->start, rc)) {
3634 block = kmalloc(sizeof(*block), GFP_NOFS);
3635 if (!block) {
3636 err = -ENOMEM;
3637 break;
3638 }
3639 block->bytenr = leaf->start;
3640 btrfs_item_key_to_cpu(leaf, &block->key, 0);
3641 block->level = 0;
3642 block->key_ready = 1;
3643 rb_node = tree_insert(blocks, block->bytenr,
3644 &block->rb_node);
3645 if (rb_node)
3646 backref_tree_panic(rb_node, -EEXIST,
3647 block->bytenr);
3648 }
3649 if (counted)
3650 added = 1;
3651 else
3652 path->slots[0] = nritems;
3653 next:
3654 path->slots[0]++;
3655
3656 }
3657 out:
3658 btrfs_free_path(path);
3659 return err;
3660 }
3661
3662 /*
3663 * helper to find all tree blocks that reference a given data extent
3664 */
3665 static noinline_for_stack
3666 int add_data_references(struct reloc_control *rc,
3667 struct btrfs_key *extent_key,
3668 struct btrfs_path *path,
3669 struct rb_root *blocks)
3670 {
3671 struct btrfs_key key;
3672 struct extent_buffer *eb;
3673 struct btrfs_extent_data_ref *dref;
3674 struct btrfs_extent_inline_ref *iref;
3675 unsigned long ptr;
3676 unsigned long end;
3677 u32 blocksize = rc->extent_root->fs_info->nodesize;
3678 int ret = 0;
3679 int err = 0;
3680
3681 eb = path->nodes[0];
3682 ptr = btrfs_item_ptr_offset(eb, path->slots[0]);
3683 end = ptr + btrfs_item_size_nr(eb, path->slots[0]);
3684 ptr += sizeof(struct btrfs_extent_item);
3685
3686 while (ptr < end) {
3687 iref = (struct btrfs_extent_inline_ref *)ptr;
3688 key.type = btrfs_get_extent_inline_ref_type(eb, iref,
3689 BTRFS_REF_TYPE_DATA);
3690 if (key.type == BTRFS_SHARED_DATA_REF_KEY) {
3691 key.offset = btrfs_extent_inline_ref_offset(eb, iref);
3692 ret = __add_tree_block(rc, key.offset, blocksize,
3693 blocks);
3694 } else if (key.type == BTRFS_EXTENT_DATA_REF_KEY) {
3695 dref = (struct btrfs_extent_data_ref *)(&iref->offset);
3696 ret = find_data_references(rc, extent_key,
3697 eb, dref, blocks);
3698 } else {
3699 ret = -EUCLEAN;
3700 btrfs_err(rc->extent_root->fs_info,
3701 "extent %llu slot %d has an invalid inline ref type",
3702 eb->start, path->slots[0]);
3703 }
3704 if (ret) {
3705 err = ret;
3706 goto out;
3707 }
3708 ptr += btrfs_extent_inline_ref_size(key.type);
3709 }
3710 WARN_ON(ptr > end);
3711
3712 while (1) {
3713 cond_resched();
3714 eb = path->nodes[0];
3715 if (path->slots[0] >= btrfs_header_nritems(eb)) {
3716 ret = btrfs_next_leaf(rc->extent_root, path);
3717 if (ret < 0) {
3718 err = ret;
3719 break;
3720 }
3721 if (ret > 0)
3722 break;
3723 eb = path->nodes[0];
3724 }
3725
3726 btrfs_item_key_to_cpu(eb, &key, path->slots[0]);
3727 if (key.objectid != extent_key->objectid)
3728 break;
3729
3730 if (key.type == BTRFS_SHARED_DATA_REF_KEY) {
3731 ret = __add_tree_block(rc, key.offset, blocksize,
3732 blocks);
3733 } else if (key.type == BTRFS_EXTENT_DATA_REF_KEY) {
3734 dref = btrfs_item_ptr(eb, path->slots[0],
3735 struct btrfs_extent_data_ref);
3736 ret = find_data_references(rc, extent_key,
3737 eb, dref, blocks);
3738 } else if (unlikely(key.type == BTRFS_EXTENT_REF_V0_KEY)) {
3739 btrfs_print_v0_err(eb->fs_info);
3740 btrfs_handle_fs_error(eb->fs_info, -EINVAL, NULL);
3741 ret = -EINVAL;
3742 } else {
3743 ret = 0;
3744 }
3745 if (ret) {
3746 err = ret;
3747 break;
3748 }
3749 path->slots[0]++;
3750 }
3751 out:
3752 btrfs_release_path(path);
3753 if (err)
3754 free_block_list(blocks);
3755 return err;
3756 }
3757
3758 /*
3759 * helper to find next unprocessed extent
3760 */
3761 static noinline_for_stack
3762 int find_next_extent(struct reloc_control *rc, struct btrfs_path *path,
3763 struct btrfs_key *extent_key)
3764 {
3765 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
3766 struct btrfs_key key;
3767 struct extent_buffer *leaf;
3768 u64 start, end, last;
3769 int ret;
3770
3771 last = rc->block_group->key.objectid + rc->block_group->key.offset;
3772 while (1) {
3773 cond_resched();
3774 if (rc->search_start >= last) {
3775 ret = 1;
3776 break;
3777 }
3778
3779 key.objectid = rc->search_start;
3780 key.type = BTRFS_EXTENT_ITEM_KEY;
3781 key.offset = 0;
3782
3783 path->search_commit_root = 1;
3784 path->skip_locking = 1;
3785 ret = btrfs_search_slot(NULL, rc->extent_root, &key, path,
3786 0, 0);
3787 if (ret < 0)
3788 break;
3789 next:
3790 leaf = path->nodes[0];
3791 if (path->slots[0] >= btrfs_header_nritems(leaf)) {
3792 ret = btrfs_next_leaf(rc->extent_root, path);
3793 if (ret != 0)
3794 break;
3795 leaf = path->nodes[0];
3796 }
3797
3798 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
3799 if (key.objectid >= last) {
3800 ret = 1;
3801 break;
3802 }
3803
3804 if (key.type != BTRFS_EXTENT_ITEM_KEY &&
3805 key.type != BTRFS_METADATA_ITEM_KEY) {
3806 path->slots[0]++;
3807 goto next;
3808 }
3809
3810 if (key.type == BTRFS_EXTENT_ITEM_KEY &&
3811 key.objectid + key.offset <= rc->search_start) {
3812 path->slots[0]++;
3813 goto next;
3814 }
3815
3816 if (key.type == BTRFS_METADATA_ITEM_KEY &&
3817 key.objectid + fs_info->nodesize <=
3818 rc->search_start) {
3819 path->slots[0]++;
3820 goto next;
3821 }
3822
3823 ret = find_first_extent_bit(&rc->processed_blocks,
3824 key.objectid, &start, &end,
3825 EXTENT_DIRTY, NULL);
3826
3827 if (ret == 0 && start <= key.objectid) {
3828 btrfs_release_path(path);
3829 rc->search_start = end + 1;
3830 } else {
3831 if (key.type == BTRFS_EXTENT_ITEM_KEY)
3832 rc->search_start = key.objectid + key.offset;
3833 else
3834 rc->search_start = key.objectid +
3835 fs_info->nodesize;
3836 memcpy(extent_key, &key, sizeof(key));
3837 return 0;
3838 }
3839 }
3840 btrfs_release_path(path);
3841 return ret;
3842 }
3843
3844 static void set_reloc_control(struct reloc_control *rc)
3845 {
3846 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
3847
3848 mutex_lock(&fs_info->reloc_mutex);
3849 fs_info->reloc_ctl = rc;
3850 mutex_unlock(&fs_info->reloc_mutex);
3851 }
3852
3853 static void unset_reloc_control(struct reloc_control *rc)
3854 {
3855 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
3856
3857 mutex_lock(&fs_info->reloc_mutex);
3858 fs_info->reloc_ctl = NULL;
3859 mutex_unlock(&fs_info->reloc_mutex);
3860 }
3861
3862 static int check_extent_flags(u64 flags)
3863 {
3864 if ((flags & BTRFS_EXTENT_FLAG_DATA) &&
3865 (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK))
3866 return 1;
3867 if (!(flags & BTRFS_EXTENT_FLAG_DATA) &&
3868 !(flags & BTRFS_EXTENT_FLAG_TREE_BLOCK))
3869 return 1;
3870 if ((flags & BTRFS_EXTENT_FLAG_DATA) &&
3871 (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF))
3872 return 1;
3873 return 0;
3874 }
3875
3876 static noinline_for_stack
3877 int prepare_to_relocate(struct reloc_control *rc)
3878 {
3879 struct btrfs_trans_handle *trans;
3880 int ret;
3881
3882 rc->block_rsv = btrfs_alloc_block_rsv(rc->extent_root->fs_info,
3883 BTRFS_BLOCK_RSV_TEMP);
3884 if (!rc->block_rsv)
3885 return -ENOMEM;
3886
3887 memset(&rc->cluster, 0, sizeof(rc->cluster));
3888 rc->search_start = rc->block_group->key.objectid;
3889 rc->extents_found = 0;
3890 rc->nodes_relocated = 0;
3891 rc->merging_rsv_size = 0;
3892 rc->reserved_bytes = 0;
3893 rc->block_rsv->size = rc->extent_root->fs_info->nodesize *
3894 RELOCATION_RESERVED_NODES;
3895 ret = btrfs_block_rsv_refill(rc->extent_root,
3896 rc->block_rsv, rc->block_rsv->size,
3897 BTRFS_RESERVE_FLUSH_ALL);
3898 if (ret)
3899 return ret;
3900
3901 rc->create_reloc_tree = 1;
3902 set_reloc_control(rc);
3903
3904 trans = btrfs_join_transaction(rc->extent_root);
3905 if (IS_ERR(trans)) {
3906 unset_reloc_control(rc);
3907 /*
3908 * extent tree is not a ref_cow tree and has no reloc_root to
3909 * cleanup. And callers are responsible to free the above
3910 * block rsv.
3911 */
3912 return PTR_ERR(trans);
3913 }
3914 btrfs_commit_transaction(trans);
3915 return 0;
3916 }
3917
3918 static noinline_for_stack int relocate_block_group(struct reloc_control *rc)
3919 {
3920 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
3921 struct rb_root blocks = RB_ROOT;
3922 struct btrfs_key key;
3923 struct btrfs_trans_handle *trans = NULL;
3924 struct btrfs_path *path;
3925 struct btrfs_extent_item *ei;
3926 u64 flags;
3927 u32 item_size;
3928 int ret;
3929 int err = 0;
3930 int progress = 0;
3931
3932 path = btrfs_alloc_path();
3933 if (!path)
3934 return -ENOMEM;
3935 path->reada = READA_FORWARD;
3936
3937 ret = prepare_to_relocate(rc);
3938 if (ret) {
3939 err = ret;
3940 goto out_free;
3941 }
3942
3943 while (1) {
3944 rc->reserved_bytes = 0;
3945 ret = btrfs_block_rsv_refill(rc->extent_root,
3946 rc->block_rsv, rc->block_rsv->size,
3947 BTRFS_RESERVE_FLUSH_ALL);
3948 if (ret) {
3949 err = ret;
3950 break;
3951 }
3952 progress++;
3953 trans = btrfs_start_transaction(rc->extent_root, 0);
3954 if (IS_ERR(trans)) {
3955 err = PTR_ERR(trans);
3956 trans = NULL;
3957 break;
3958 }
3959 restart:
3960 if (update_backref_cache(trans, &rc->backref_cache)) {
3961 btrfs_end_transaction(trans);
3962 trans = NULL;
3963 continue;
3964 }
3965
3966 ret = find_next_extent(rc, path, &key);
3967 if (ret < 0)
3968 err = ret;
3969 if (ret != 0)
3970 break;
3971
3972 rc->extents_found++;
3973
3974 ei = btrfs_item_ptr(path->nodes[0], path->slots[0],
3975 struct btrfs_extent_item);
3976 item_size = btrfs_item_size_nr(path->nodes[0], path->slots[0]);
3977 if (item_size >= sizeof(*ei)) {
3978 flags = btrfs_extent_flags(path->nodes[0], ei);
3979 ret = check_extent_flags(flags);
3980 BUG_ON(ret);
3981 } else if (unlikely(item_size == sizeof(struct btrfs_extent_item_v0))) {
3982 err = -EINVAL;
3983 btrfs_print_v0_err(trans->fs_info);
3984 btrfs_abort_transaction(trans, err);
3985 break;
3986 } else {
3987 BUG();
3988 }
3989
3990 if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) {
3991 ret = add_tree_block(rc, &key, path, &blocks);
3992 } else if (rc->stage == UPDATE_DATA_PTRS &&
3993 (flags & BTRFS_EXTENT_FLAG_DATA)) {
3994 ret = add_data_references(rc, &key, path, &blocks);
3995 } else {
3996 btrfs_release_path(path);
3997 ret = 0;
3998 }
3999 if (ret < 0) {
4000 err = ret;
4001 break;
4002 }
4003
4004 if (!RB_EMPTY_ROOT(&blocks)) {
4005 ret = relocate_tree_blocks(trans, rc, &blocks);
4006 if (ret < 0) {
4007 /*
4008 * if we fail to relocate tree blocks, force to update
4009 * backref cache when committing transaction.
4010 */
4011 rc->backref_cache.last_trans = trans->transid - 1;
4012
4013 if (ret != -EAGAIN) {
4014 err = ret;
4015 break;
4016 }
4017 rc->extents_found--;
4018 rc->search_start = key.objectid;
4019 }
4020 }
4021
4022 btrfs_end_transaction_throttle(trans);
4023 btrfs_btree_balance_dirty(fs_info);
4024 trans = NULL;
4025
4026 if (rc->stage == MOVE_DATA_EXTENTS &&
4027 (flags & BTRFS_EXTENT_FLAG_DATA)) {
4028 rc->found_file_extent = 1;
4029 ret = relocate_data_extent(rc->data_inode,
4030 &key, &rc->cluster);
4031 if (ret < 0) {
4032 err = ret;
4033 break;
4034 }
4035 }
4036 }
4037 if (trans && progress && err == -ENOSPC) {
4038 ret = btrfs_force_chunk_alloc(trans, rc->block_group->flags);
4039 if (ret == 1) {
4040 err = 0;
4041 progress = 0;
4042 goto restart;
4043 }
4044 }
4045
4046 btrfs_release_path(path);
4047 clear_extent_bits(&rc->processed_blocks, 0, (u64)-1, EXTENT_DIRTY);
4048
4049 if (trans) {
4050 btrfs_end_transaction_throttle(trans);
4051 btrfs_btree_balance_dirty(fs_info);
4052 }
4053
4054 if (!err) {
4055 ret = relocate_file_extent_cluster(rc->data_inode,
4056 &rc->cluster);
4057 if (ret < 0)
4058 err = ret;
4059 }
4060
4061 rc->create_reloc_tree = 0;
4062 set_reloc_control(rc);
4063
4064 backref_cache_cleanup(&rc->backref_cache);
4065 btrfs_block_rsv_release(fs_info, rc->block_rsv, (u64)-1);
4066
4067 err = prepare_to_merge(rc, err);
4068
4069 merge_reloc_roots(rc);
4070
4071 rc->merge_reloc_tree = 0;
4072 unset_reloc_control(rc);
4073 btrfs_block_rsv_release(fs_info, rc->block_rsv, (u64)-1);
4074
4075 /* get rid of pinned extents */
4076 trans = btrfs_join_transaction(rc->extent_root);
4077 if (IS_ERR(trans)) {
4078 err = PTR_ERR(trans);
4079 goto out_free;
4080 }
4081 btrfs_commit_transaction(trans);
4082 out_free:
4083 btrfs_free_block_rsv(fs_info, rc->block_rsv);
4084 btrfs_free_path(path);
4085 return err;
4086 }
4087
4088 static int __insert_orphan_inode(struct btrfs_trans_handle *trans,
4089 struct btrfs_root *root, u64 objectid)
4090 {
4091 struct btrfs_path *path;
4092 struct btrfs_inode_item *item;
4093 struct extent_buffer *leaf;
4094 int ret;
4095
4096 path = btrfs_alloc_path();
4097 if (!path)
4098 return -ENOMEM;
4099
4100 ret = btrfs_insert_empty_inode(trans, root, path, objectid);
4101 if (ret)
4102 goto out;
4103
4104 leaf = path->nodes[0];
4105 item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_inode_item);
4106 memzero_extent_buffer(leaf, (unsigned long)item, sizeof(*item));
4107 btrfs_set_inode_generation(leaf, item, 1);
4108 btrfs_set_inode_size(leaf, item, 0);
4109 btrfs_set_inode_mode(leaf, item, S_IFREG | 0600);
4110 btrfs_set_inode_flags(leaf, item, BTRFS_INODE_NOCOMPRESS |
4111 BTRFS_INODE_PREALLOC);
4112 btrfs_mark_buffer_dirty(leaf);
4113 out:
4114 btrfs_free_path(path);
4115 return ret;
4116 }
4117
4118 /*
4119 * helper to create inode for data relocation.
4120 * the inode is in data relocation tree and its link count is 0
4121 */
4122 static noinline_for_stack
4123 struct inode *create_reloc_inode(struct btrfs_fs_info *fs_info,
4124 struct btrfs_block_group_cache *group)
4125 {
4126 struct inode *inode = NULL;
4127 struct btrfs_trans_handle *trans;
4128 struct btrfs_root *root;
4129 struct btrfs_key key;
4130 u64 objectid;
4131 int err = 0;
4132
4133 root = read_fs_root(fs_info, BTRFS_DATA_RELOC_TREE_OBJECTID);
4134 if (IS_ERR(root))
4135 return ERR_CAST(root);
4136
4137 trans = btrfs_start_transaction(root, 6);
4138 if (IS_ERR(trans))
4139 return ERR_CAST(trans);
4140
4141 err = btrfs_find_free_objectid(root, &objectid);
4142 if (err)
4143 goto out;
4144
4145 err = __insert_orphan_inode(trans, root, objectid);
4146 BUG_ON(err);
4147
4148 key.objectid = objectid;
4149 key.type = BTRFS_INODE_ITEM_KEY;
4150 key.offset = 0;
4151 inode = btrfs_iget(fs_info->sb, &key, root, NULL);
4152 BUG_ON(IS_ERR(inode));
4153 BTRFS_I(inode)->index_cnt = group->key.objectid;
4154
4155 err = btrfs_orphan_add(trans, BTRFS_I(inode));
4156 out:
4157 btrfs_end_transaction(trans);
4158 btrfs_btree_balance_dirty(fs_info);
4159 if (err) {
4160 if (inode)
4161 iput(inode);
4162 inode = ERR_PTR(err);
4163 }
4164 return inode;
4165 }
4166
4167 static struct reloc_control *alloc_reloc_control(void)
4168 {
4169 struct reloc_control *rc;
4170
4171 rc = kzalloc(sizeof(*rc), GFP_NOFS);
4172 if (!rc)
4173 return NULL;
4174
4175 INIT_LIST_HEAD(&rc->reloc_roots);
4176 backref_cache_init(&rc->backref_cache);
4177 mapping_tree_init(&rc->reloc_root_tree);
4178 extent_io_tree_init(&rc->processed_blocks, NULL);
4179 return rc;
4180 }
4181
4182 /*
4183 * Print the block group being relocated
4184 */
4185 static void describe_relocation(struct btrfs_fs_info *fs_info,
4186 struct btrfs_block_group_cache *block_group)
4187 {
4188 char buf[128]; /* prefixed by a '|' that'll be dropped */
4189 u64 flags = block_group->flags;
4190
4191 /* Shouldn't happen */
4192 if (!flags) {
4193 strcpy(buf, "|NONE");
4194 } else {
4195 char *bp = buf;
4196
4197 #define DESCRIBE_FLAG(f, d) \
4198 if (flags & BTRFS_BLOCK_GROUP_##f) { \
4199 bp += snprintf(bp, buf - bp + sizeof(buf), "|%s", d); \
4200 flags &= ~BTRFS_BLOCK_GROUP_##f; \
4201 }
4202 DESCRIBE_FLAG(DATA, "data");
4203 DESCRIBE_FLAG(SYSTEM, "system");
4204 DESCRIBE_FLAG(METADATA, "metadata");
4205 DESCRIBE_FLAG(RAID0, "raid0");
4206 DESCRIBE_FLAG(RAID1, "raid1");
4207 DESCRIBE_FLAG(DUP, "dup");
4208 DESCRIBE_FLAG(RAID10, "raid10");
4209 DESCRIBE_FLAG(RAID5, "raid5");
4210 DESCRIBE_FLAG(RAID6, "raid6");
4211 if (flags)
4212 snprintf(bp, buf - bp + sizeof(buf), "|0x%llx", flags);
4213 #undef DESCRIBE_FLAG
4214 }
4215
4216 btrfs_info(fs_info,
4217 "relocating block group %llu flags %s",
4218 block_group->key.objectid, buf + 1);
4219 }
4220
4221 /*
4222 * function to relocate all extents in a block group.
4223 */
4224 int btrfs_relocate_block_group(struct btrfs_fs_info *fs_info, u64 group_start)
4225 {
4226 struct btrfs_root *extent_root = fs_info->extent_root;
4227 struct reloc_control *rc;
4228 struct inode *inode;
4229 struct btrfs_path *path;
4230 int ret;
4231 int rw = 0;
4232 int err = 0;
4233
4234 rc = alloc_reloc_control();
4235 if (!rc)
4236 return -ENOMEM;
4237
4238 rc->extent_root = extent_root;
4239
4240 rc->block_group = btrfs_lookup_block_group(fs_info, group_start);
4241 BUG_ON(!rc->block_group);
4242
4243 ret = btrfs_inc_block_group_ro(rc->block_group);
4244 if (ret) {
4245 err = ret;
4246 goto out;
4247 }
4248 rw = 1;
4249
4250 path = btrfs_alloc_path();
4251 if (!path) {
4252 err = -ENOMEM;
4253 goto out;
4254 }
4255
4256 inode = lookup_free_space_inode(fs_info, rc->block_group, path);
4257 btrfs_free_path(path);
4258
4259 if (!IS_ERR(inode))
4260 ret = delete_block_group_cache(fs_info, rc->block_group, inode, 0);
4261 else
4262 ret = PTR_ERR(inode);
4263
4264 if (ret && ret != -ENOENT) {
4265 err = ret;
4266 goto out;
4267 }
4268
4269 rc->data_inode = create_reloc_inode(fs_info, rc->block_group);
4270 if (IS_ERR(rc->data_inode)) {
4271 err = PTR_ERR(rc->data_inode);
4272 rc->data_inode = NULL;
4273 goto out;
4274 }
4275
4276 describe_relocation(fs_info, rc->block_group);
4277
4278 btrfs_wait_block_group_reservations(rc->block_group);
4279 btrfs_wait_nocow_writers(rc->block_group);
4280 btrfs_wait_ordered_roots(fs_info, U64_MAX,
4281 rc->block_group->key.objectid,
4282 rc->block_group->key.offset);
4283
4284 while (1) {
4285 mutex_lock(&fs_info->cleaner_mutex);
4286 ret = relocate_block_group(rc);
4287 mutex_unlock(&fs_info->cleaner_mutex);
4288 if (ret < 0) {
4289 err = ret;
4290 goto out;
4291 }
4292
4293 if (rc->extents_found == 0)
4294 break;
4295
4296 btrfs_info(fs_info, "found %llu extents", rc->extents_found);
4297
4298 if (rc->stage == MOVE_DATA_EXTENTS && rc->found_file_extent) {
4299 ret = btrfs_wait_ordered_range(rc->data_inode, 0,
4300 (u64)-1);
4301 if (ret) {
4302 err = ret;
4303 goto out;
4304 }
4305 invalidate_mapping_pages(rc->data_inode->i_mapping,
4306 0, -1);
4307 rc->stage = UPDATE_DATA_PTRS;
4308 }
4309 }
4310
4311 WARN_ON(rc->block_group->pinned > 0);
4312 WARN_ON(rc->block_group->reserved > 0);
4313 WARN_ON(btrfs_block_group_used(&rc->block_group->item) > 0);
4314 out:
4315 if (err && rw)
4316 btrfs_dec_block_group_ro(rc->block_group);
4317 iput(rc->data_inode);
4318 btrfs_put_block_group(rc->block_group);
4319 kfree(rc);
4320 return err;
4321 }
4322
4323 static noinline_for_stack int mark_garbage_root(struct btrfs_root *root)
4324 {
4325 struct btrfs_fs_info *fs_info = root->fs_info;
4326 struct btrfs_trans_handle *trans;
4327 int ret, err;
4328
4329 trans = btrfs_start_transaction(fs_info->tree_root, 0);
4330 if (IS_ERR(trans))
4331 return PTR_ERR(trans);
4332
4333 memset(&root->root_item.drop_progress, 0,
4334 sizeof(root->root_item.drop_progress));
4335 root->root_item.drop_level = 0;
4336 btrfs_set_root_refs(&root->root_item, 0);
4337 ret = btrfs_update_root(trans, fs_info->tree_root,
4338 &root->root_key, &root->root_item);
4339
4340 err = btrfs_end_transaction(trans);
4341 if (err)
4342 return err;
4343 return ret;
4344 }
4345
4346 /*
4347 * recover relocation interrupted by system crash.
4348 *
4349 * this function resumes merging reloc trees with corresponding fs trees.
4350 * this is important for keeping the sharing of tree blocks
4351 */
4352 int btrfs_recover_relocation(struct btrfs_root *root)
4353 {
4354 struct btrfs_fs_info *fs_info = root->fs_info;
4355 LIST_HEAD(reloc_roots);
4356 struct btrfs_key key;
4357 struct btrfs_root *fs_root;
4358 struct btrfs_root *reloc_root;
4359 struct btrfs_path *path;
4360 struct extent_buffer *leaf;
4361 struct reloc_control *rc = NULL;
4362 struct btrfs_trans_handle *trans;
4363 int ret;
4364 int err = 0;
4365
4366 path = btrfs_alloc_path();
4367 if (!path)
4368 return -ENOMEM;
4369 path->reada = READA_BACK;
4370
4371 key.objectid = BTRFS_TREE_RELOC_OBJECTID;
4372 key.type = BTRFS_ROOT_ITEM_KEY;
4373 key.offset = (u64)-1;
4374
4375 while (1) {
4376 ret = btrfs_search_slot(NULL, fs_info->tree_root, &key,
4377 path, 0, 0);
4378 if (ret < 0) {
4379 err = ret;
4380 goto out;
4381 }
4382 if (ret > 0) {
4383 if (path->slots[0] == 0)
4384 break;
4385 path->slots[0]--;
4386 }
4387 leaf = path->nodes[0];
4388 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
4389 btrfs_release_path(path);
4390
4391 if (key.objectid != BTRFS_TREE_RELOC_OBJECTID ||
4392 key.type != BTRFS_ROOT_ITEM_KEY)
4393 break;
4394
4395 reloc_root = btrfs_read_fs_root(root, &key);
4396 if (IS_ERR(reloc_root)) {
4397 err = PTR_ERR(reloc_root);
4398 goto out;
4399 }
4400
4401 list_add(&reloc_root->root_list, &reloc_roots);
4402
4403 if (btrfs_root_refs(&reloc_root->root_item) > 0) {
4404 fs_root = read_fs_root(fs_info,
4405 reloc_root->root_key.offset);
4406 if (IS_ERR(fs_root)) {
4407 ret = PTR_ERR(fs_root);
4408 if (ret != -ENOENT) {
4409 err = ret;
4410 goto out;
4411 }
4412 ret = mark_garbage_root(reloc_root);
4413 if (ret < 0) {
4414 err = ret;
4415 goto out;
4416 }
4417 }
4418 }
4419
4420 if (key.offset == 0)
4421 break;
4422
4423 key.offset--;
4424 }
4425 btrfs_release_path(path);
4426
4427 if (list_empty(&reloc_roots))
4428 goto out;
4429
4430 rc = alloc_reloc_control();
4431 if (!rc) {
4432 err = -ENOMEM;
4433 goto out;
4434 }
4435
4436 rc->extent_root = fs_info->extent_root;
4437
4438 set_reloc_control(rc);
4439
4440 trans = btrfs_join_transaction(rc->extent_root);
4441 if (IS_ERR(trans)) {
4442 unset_reloc_control(rc);
4443 err = PTR_ERR(trans);
4444 goto out_free;
4445 }
4446
4447 rc->merge_reloc_tree = 1;
4448
4449 while (!list_empty(&reloc_roots)) {
4450 reloc_root = list_entry(reloc_roots.next,
4451 struct btrfs_root, root_list);
4452 list_del(&reloc_root->root_list);
4453
4454 if (btrfs_root_refs(&reloc_root->root_item) == 0) {
4455 list_add_tail(&reloc_root->root_list,
4456 &rc->reloc_roots);
4457 continue;
4458 }
4459
4460 fs_root = read_fs_root(fs_info, reloc_root->root_key.offset);
4461 if (IS_ERR(fs_root)) {
4462 err = PTR_ERR(fs_root);
4463 goto out_free;
4464 }
4465
4466 err = __add_reloc_root(reloc_root);
4467 BUG_ON(err < 0); /* -ENOMEM or logic error */
4468 fs_root->reloc_root = reloc_root;
4469 }
4470
4471 err = btrfs_commit_transaction(trans);
4472 if (err)
4473 goto out_free;
4474
4475 merge_reloc_roots(rc);
4476
4477 unset_reloc_control(rc);
4478
4479 trans = btrfs_join_transaction(rc->extent_root);
4480 if (IS_ERR(trans)) {
4481 err = PTR_ERR(trans);
4482 goto out_free;
4483 }
4484 err = btrfs_commit_transaction(trans);
4485 out_free:
4486 kfree(rc);
4487 out:
4488 if (!list_empty(&reloc_roots))
4489 free_reloc_roots(&reloc_roots);
4490
4491 btrfs_free_path(path);
4492
4493 if (err == 0) {
4494 /* cleanup orphan inode in data relocation tree */
4495 fs_root = read_fs_root(fs_info, BTRFS_DATA_RELOC_TREE_OBJECTID);
4496 if (IS_ERR(fs_root))
4497 err = PTR_ERR(fs_root);
4498 else
4499 err = btrfs_orphan_cleanup(fs_root);
4500 }
4501 return err;
4502 }
4503
4504 /*
4505 * helper to add ordered checksum for data relocation.
4506 *
4507 * cloning checksum properly handles the nodatasum extents.
4508 * it also saves CPU time to re-calculate the checksum.
4509 */
4510 int btrfs_reloc_clone_csums(struct inode *inode, u64 file_pos, u64 len)
4511 {
4512 struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
4513 struct btrfs_ordered_sum *sums;
4514 struct btrfs_ordered_extent *ordered;
4515 int ret;
4516 u64 disk_bytenr;
4517 u64 new_bytenr;
4518 LIST_HEAD(list);
4519
4520 ordered = btrfs_lookup_ordered_extent(inode, file_pos);
4521 BUG_ON(ordered->file_offset != file_pos || ordered->len != len);
4522
4523 disk_bytenr = file_pos + BTRFS_I(inode)->index_cnt;
4524 ret = btrfs_lookup_csums_range(fs_info->csum_root, disk_bytenr,
4525 disk_bytenr + len - 1, &list, 0);
4526 if (ret)
4527 goto out;
4528
4529 while (!list_empty(&list)) {
4530 sums = list_entry(list.next, struct btrfs_ordered_sum, list);
4531 list_del_init(&sums->list);
4532
4533 /*
4534 * We need to offset the new_bytenr based on where the csum is.
4535 * We need to do this because we will read in entire prealloc
4536 * extents but we may have written to say the middle of the
4537 * prealloc extent, so we need to make sure the csum goes with
4538 * the right disk offset.
4539 *
4540 * We can do this because the data reloc inode refers strictly
4541 * to the on disk bytes, so we don't have to worry about
4542 * disk_len vs real len like with real inodes since it's all
4543 * disk length.
4544 */
4545 new_bytenr = ordered->start + (sums->bytenr - disk_bytenr);
4546 sums->bytenr = new_bytenr;
4547
4548 btrfs_add_ordered_sum(inode, ordered, sums);
4549 }
4550 out:
4551 btrfs_put_ordered_extent(ordered);
4552 return ret;
4553 }
4554
4555 int btrfs_reloc_cow_block(struct btrfs_trans_handle *trans,
4556 struct btrfs_root *root, struct extent_buffer *buf,
4557 struct extent_buffer *cow)
4558 {
4559 struct btrfs_fs_info *fs_info = root->fs_info;
4560 struct reloc_control *rc;
4561 struct backref_node *node;
4562 int first_cow = 0;
4563 int level;
4564 int ret = 0;
4565
4566 rc = fs_info->reloc_ctl;
4567 if (!rc)
4568 return 0;
4569
4570 BUG_ON(rc->stage == UPDATE_DATA_PTRS &&
4571 root->root_key.objectid == BTRFS_DATA_RELOC_TREE_OBJECTID);
4572
4573 if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID) {
4574 if (buf == root->node)
4575 __update_reloc_root(root, cow->start);
4576 }
4577
4578 level = btrfs_header_level(buf);
4579 if (btrfs_header_generation(buf) <=
4580 btrfs_root_last_snapshot(&root->root_item))
4581 first_cow = 1;
4582
4583 if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID &&
4584 rc->create_reloc_tree) {
4585 WARN_ON(!first_cow && level == 0);
4586
4587 node = rc->backref_cache.path[level];
4588 BUG_ON(node->bytenr != buf->start &&
4589 node->new_bytenr != buf->start);
4590
4591 drop_node_buffer(node);
4592 extent_buffer_get(cow);
4593 node->eb = cow;
4594 node->new_bytenr = cow->start;
4595
4596 if (!node->pending) {
4597 list_move_tail(&node->list,
4598 &rc->backref_cache.pending[level]);
4599 node->pending = 1;
4600 }
4601
4602 if (first_cow)
4603 __mark_block_processed(rc, node);
4604
4605 if (first_cow && level > 0)
4606 rc->nodes_relocated += buf->len;
4607 }
4608
4609 if (level == 0 && first_cow && rc->stage == UPDATE_DATA_PTRS)
4610 ret = replace_file_extents(trans, rc, root, cow);
4611 return ret;
4612 }
4613
4614 /*
4615 * called before creating snapshot. it calculates metadata reservation
4616 * required for relocating tree blocks in the snapshot
4617 */
4618 void btrfs_reloc_pre_snapshot(struct btrfs_pending_snapshot *pending,
4619 u64 *bytes_to_reserve)
4620 {
4621 struct btrfs_root *root;
4622 struct reloc_control *rc;
4623
4624 root = pending->root;
4625 if (!root->reloc_root)
4626 return;
4627
4628 rc = root->fs_info->reloc_ctl;
4629 if (!rc->merge_reloc_tree)
4630 return;
4631
4632 root = root->reloc_root;
4633 BUG_ON(btrfs_root_refs(&root->root_item) == 0);
4634 /*
4635 * relocation is in the stage of merging trees. the space
4636 * used by merging a reloc tree is twice the size of
4637 * relocated tree nodes in the worst case. half for cowing
4638 * the reloc tree, half for cowing the fs tree. the space
4639 * used by cowing the reloc tree will be freed after the
4640 * tree is dropped. if we create snapshot, cowing the fs
4641 * tree may use more space than it frees. so we need
4642 * reserve extra space.
4643 */
4644 *bytes_to_reserve += rc->nodes_relocated;
4645 }
4646
4647 /*
4648 * called after snapshot is created. migrate block reservation
4649 * and create reloc root for the newly created snapshot
4650 */
4651 int btrfs_reloc_post_snapshot(struct btrfs_trans_handle *trans,
4652 struct btrfs_pending_snapshot *pending)
4653 {
4654 struct btrfs_root *root = pending->root;
4655 struct btrfs_root *reloc_root;
4656 struct btrfs_root *new_root;
4657 struct reloc_control *rc;
4658 int ret;
4659
4660 if (!root->reloc_root)
4661 return 0;
4662
4663 rc = root->fs_info->reloc_ctl;
4664 rc->merging_rsv_size += rc->nodes_relocated;
4665
4666 if (rc->merge_reloc_tree) {
4667 ret = btrfs_block_rsv_migrate(&pending->block_rsv,
4668 rc->block_rsv,
4669 rc->nodes_relocated, true);
4670 if (ret)
4671 return ret;
4672 }
4673
4674 new_root = pending->snap;
4675 reloc_root = create_reloc_root(trans, root->reloc_root,
4676 new_root->root_key.objectid);
4677 if (IS_ERR(reloc_root))
4678 return PTR_ERR(reloc_root);
4679
4680 ret = __add_reloc_root(reloc_root);
4681 BUG_ON(ret < 0);
4682 new_root->reloc_root = reloc_root;
4683
4684 if (rc->create_reloc_tree)
4685 ret = clone_backref_node(trans, rc, root, reloc_root);
4686 return ret;
4687 }
Linux with added FPC-III support