1 // SPDX-License-Identifier: GPL-2.0
3 * Copyright (C) 2009 Oracle. All rights reserved.
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 <linux/error-injection.h>
15 #include "transaction.h"
18 #include "btrfs_inode.h"
19 #include "async-thread.h"
20 #include "free-space-cache.h"
21 #include "inode-map.h"
23 #include "print-tree.h"
24 #include "delalloc-space.h"
25 #include "block-group.h"
32 * [What does relocation do]
34 * The objective of relocation is to relocate all extents of the target block
35 * group to other block groups.
36 * This is utilized by resize (shrink only), profile converting, compacting
37 * space, or balance routine to spread chunks over devices.
40 * ------------------------------------------------------------------
41 * BG A: 10 data extents | BG A: deleted
42 * BG B: 2 data extents | BG B: 10 data extents (2 old + 8 relocated)
43 * BG C: 1 extents | BG C: 3 data extents (1 old + 2 relocated)
45 * [How does relocation work]
47 * 1. Mark the target block group read-only
48 * New extents won't be allocated from the target block group.
50 * 2.1 Record each extent in the target block group
51 * To build a proper map of extents to be relocated.
53 * 2.2 Build data reloc tree and reloc trees
54 * Data reloc tree will contain an inode, recording all newly relocated
56 * There will be only one data reloc tree for one data block group.
58 * Reloc tree will be a special snapshot of its source tree, containing
59 * relocated tree blocks.
60 * Each tree referring to a tree block in target block group will get its
63 * 2.3 Swap source tree with its corresponding reloc tree
64 * Each involved tree only refers to new extents after swap.
66 * 3. Cleanup reloc trees and data reloc tree.
67 * As old extents in the target block group are still referenced by reloc
68 * trees, we need to clean them up before really freeing the target block
71 * The main complexity is in steps 2.2 and 2.3.
73 * The entry point of relocation is relocate_block_group() function.
76 #define RELOCATION_RESERVED_NODES 256
78 * map address of tree root to tree
82 struct rb_node rb_node;
84 }; /* Use rb_simle_node for search/insert */
89 struct rb_root rb_root;
94 * present a tree block to process
98 struct rb_node rb_node;
100 }; /* Use rb_simple_node for search/insert */
101 struct btrfs_key key;
102 unsigned int level:8;
103 unsigned int key_ready:1;
106 #define MAX_EXTENTS 128
108 struct file_extent_cluster {
111 u64 boundary[MAX_EXTENTS];
115 struct reloc_control {
116 /* block group to relocate */
117 struct btrfs_block_group *block_group;
119 struct btrfs_root *extent_root;
120 /* inode for moving data */
121 struct inode *data_inode;
123 struct btrfs_block_rsv *block_rsv;
125 struct btrfs_backref_cache backref_cache;
127 struct file_extent_cluster cluster;
128 /* tree blocks have been processed */
129 struct extent_io_tree processed_blocks;
130 /* map start of tree root to corresponding reloc tree */
131 struct mapping_tree reloc_root_tree;
132 /* list of reloc trees */
133 struct list_head reloc_roots;
134 /* list of subvolume trees that get relocated */
135 struct list_head dirty_subvol_roots;
136 /* size of metadata reservation for merging reloc trees */
137 u64 merging_rsv_size;
138 /* size of relocated tree nodes */
140 /* reserved size for block group relocation*/
146 unsigned int stage:8;
147 unsigned int create_reloc_tree:1;
148 unsigned int merge_reloc_tree:1;
149 unsigned int found_file_extent:1;
152 /* stages of data relocation */
153 #define MOVE_DATA_EXTENTS 0
154 #define UPDATE_DATA_PTRS 1
156 static void mark_block_processed(struct reloc_control *rc,
157 struct btrfs_backref_node *node)
161 if (node->level == 0 ||
162 in_range(node->bytenr, rc->block_group->start,
163 rc->block_group->length)) {
164 blocksize = rc->extent_root->fs_info->nodesize;
165 set_extent_bits(&rc->processed_blocks, node->bytenr,
166 node->bytenr + blocksize - 1, EXTENT_DIRTY);
172 static void mapping_tree_init(struct mapping_tree *tree)
174 tree->rb_root = RB_ROOT;
175 spin_lock_init(&tree->lock);
179 * walk up backref nodes until reach node presents tree root
181 static struct btrfs_backref_node *walk_up_backref(
182 struct btrfs_backref_node *node,
183 struct btrfs_backref_edge *edges[], int *index)
185 struct btrfs_backref_edge *edge;
188 while (!list_empty(&node->upper)) {
189 edge = list_entry(node->upper.next,
190 struct btrfs_backref_edge, list[LOWER]);
192 node = edge->node[UPPER];
194 BUG_ON(node->detached);
200 * walk down backref nodes to find start of next reference path
202 static struct btrfs_backref_node *walk_down_backref(
203 struct btrfs_backref_edge *edges[], int *index)
205 struct btrfs_backref_edge *edge;
206 struct btrfs_backref_node *lower;
210 edge = edges[idx - 1];
211 lower = edge->node[LOWER];
212 if (list_is_last(&edge->list[LOWER], &lower->upper)) {
216 edge = list_entry(edge->list[LOWER].next,
217 struct btrfs_backref_edge, list[LOWER]);
218 edges[idx - 1] = edge;
220 return edge->node[UPPER];
226 static void update_backref_node(struct btrfs_backref_cache *cache,
227 struct btrfs_backref_node *node, u64 bytenr)
229 struct rb_node *rb_node;
230 rb_erase(&node->rb_node, &cache->rb_root);
231 node->bytenr = bytenr;
232 rb_node = rb_simple_insert(&cache->rb_root, node->bytenr, &node->rb_node);
234 btrfs_backref_panic(cache->fs_info, bytenr, -EEXIST);
238 * update backref cache after a transaction commit
240 static int update_backref_cache(struct btrfs_trans_handle *trans,
241 struct btrfs_backref_cache *cache)
243 struct btrfs_backref_node *node;
246 if (cache->last_trans == 0) {
247 cache->last_trans = trans->transid;
251 if (cache->last_trans == trans->transid)
255 * detached nodes are used to avoid unnecessary backref
256 * lookup. transaction commit changes the extent tree.
257 * so the detached nodes are no longer useful.
259 while (!list_empty(&cache->detached)) {
260 node = list_entry(cache->detached.next,
261 struct btrfs_backref_node, list);
262 btrfs_backref_cleanup_node(cache, node);
265 while (!list_empty(&cache->changed)) {
266 node = list_entry(cache->changed.next,
267 struct btrfs_backref_node, list);
268 list_del_init(&node->list);
269 BUG_ON(node->pending);
270 update_backref_node(cache, node, node->new_bytenr);
274 * some nodes can be left in the pending list if there were
275 * errors during processing the pending nodes.
277 for (level = 0; level < BTRFS_MAX_LEVEL; level++) {
278 list_for_each_entry(node, &cache->pending[level], list) {
279 BUG_ON(!node->pending);
280 if (node->bytenr == node->new_bytenr)
282 update_backref_node(cache, node, node->new_bytenr);
286 cache->last_trans = 0;
290 static bool reloc_root_is_dead(struct btrfs_root *root)
293 * Pair with set_bit/clear_bit in clean_dirty_subvols and
294 * btrfs_update_reloc_root. We need to see the updated bit before
295 * trying to access reloc_root
298 if (test_bit(BTRFS_ROOT_DEAD_RELOC_TREE, &root->state))
304 * Check if this subvolume tree has valid reloc tree.
306 * Reloc tree after swap is considered dead, thus not considered as valid.
307 * This is enough for most callers, as they don't distinguish dead reloc root
308 * from no reloc root. But btrfs_should_ignore_reloc_root() below is a
311 static bool have_reloc_root(struct btrfs_root *root)
313 if (reloc_root_is_dead(root))
315 if (!root->reloc_root)
320 int btrfs_should_ignore_reloc_root(struct btrfs_root *root)
322 struct btrfs_root *reloc_root;
324 if (!test_bit(BTRFS_ROOT_SHAREABLE, &root->state))
327 /* This root has been merged with its reloc tree, we can ignore it */
328 if (reloc_root_is_dead(root))
331 reloc_root = root->reloc_root;
335 if (btrfs_header_generation(reloc_root->commit_root) ==
336 root->fs_info->running_transaction->transid)
339 * if there is reloc tree and it was created in previous
340 * transaction backref lookup can find the reloc tree,
341 * so backref node for the fs tree root is useless for
348 * find reloc tree by address of tree root
350 struct btrfs_root *find_reloc_root(struct btrfs_fs_info *fs_info, u64 bytenr)
352 struct reloc_control *rc = fs_info->reloc_ctl;
353 struct rb_node *rb_node;
354 struct mapping_node *node;
355 struct btrfs_root *root = NULL;
358 spin_lock(&rc->reloc_root_tree.lock);
359 rb_node = rb_simple_search(&rc->reloc_root_tree.rb_root, bytenr);
361 node = rb_entry(rb_node, struct mapping_node, rb_node);
362 root = (struct btrfs_root *)node->data;
364 spin_unlock(&rc->reloc_root_tree.lock);
365 return btrfs_grab_root(root);
369 * For useless nodes, do two major clean ups:
371 * - Cleanup the children edges and nodes
372 * If child node is also orphan (no parent) during cleanup, then the child
373 * node will also be cleaned up.
375 * - Freeing up leaves (level 0), keeps nodes detached
376 * For nodes, the node is still cached as "detached"
378 * Return false if @node is not in the @useless_nodes list.
379 * Return true if @node is in the @useless_nodes list.
381 static bool handle_useless_nodes(struct reloc_control *rc,
382 struct btrfs_backref_node *node)
384 struct btrfs_backref_cache *cache = &rc->backref_cache;
385 struct list_head *useless_node = &cache->useless_node;
388 while (!list_empty(useless_node)) {
389 struct btrfs_backref_node *cur;
391 cur = list_first_entry(useless_node, struct btrfs_backref_node,
393 list_del_init(&cur->list);
395 /* Only tree root nodes can be added to @useless_nodes */
396 ASSERT(list_empty(&cur->upper));
401 /* The node is the lowest node */
403 list_del_init(&cur->lower);
407 /* Cleanup the lower edges */
408 while (!list_empty(&cur->lower)) {
409 struct btrfs_backref_edge *edge;
410 struct btrfs_backref_node *lower;
412 edge = list_entry(cur->lower.next,
413 struct btrfs_backref_edge, list[UPPER]);
414 list_del(&edge->list[UPPER]);
415 list_del(&edge->list[LOWER]);
416 lower = edge->node[LOWER];
417 btrfs_backref_free_edge(cache, edge);
419 /* Child node is also orphan, queue for cleanup */
420 if (list_empty(&lower->upper))
421 list_add(&lower->list, useless_node);
423 /* Mark this block processed for relocation */
424 mark_block_processed(rc, cur);
427 * Backref nodes for tree leaves are deleted from the cache.
428 * Backref nodes for upper level tree blocks are left in the
429 * cache to avoid unnecessary backref lookup.
431 if (cur->level > 0) {
432 list_add(&cur->list, &cache->detached);
435 rb_erase(&cur->rb_node, &cache->rb_root);
436 btrfs_backref_free_node(cache, cur);
443 * Build backref tree for a given tree block. Root of the backref tree
444 * corresponds the tree block, leaves of the backref tree correspond roots of
445 * b-trees that reference the tree block.
447 * The basic idea of this function is check backrefs of a given block to find
448 * upper level blocks that reference the block, and then check backrefs of
449 * these upper level blocks recursively. The recursion stops when tree root is
450 * reached or backrefs for the block is cached.
452 * NOTE: if we find that backrefs for a block are cached, we know backrefs for
453 * all upper level blocks that directly/indirectly reference the block are also
456 static noinline_for_stack struct btrfs_backref_node *build_backref_tree(
457 struct reloc_control *rc, struct btrfs_key *node_key,
458 int level, u64 bytenr)
460 struct btrfs_backref_iter *iter;
461 struct btrfs_backref_cache *cache = &rc->backref_cache;
462 /* For searching parent of TREE_BLOCK_REF */
463 struct btrfs_path *path;
464 struct btrfs_backref_node *cur;
465 struct btrfs_backref_node *node = NULL;
466 struct btrfs_backref_edge *edge;
470 iter = btrfs_backref_iter_alloc(rc->extent_root->fs_info, GFP_NOFS);
472 return ERR_PTR(-ENOMEM);
473 path = btrfs_alloc_path();
479 node = btrfs_backref_alloc_node(cache, bytenr, level);
488 /* Breadth-first search to build backref cache */
490 ret = btrfs_backref_add_tree_node(cache, path, iter, node_key,
496 edge = list_first_entry_or_null(&cache->pending_edge,
497 struct btrfs_backref_edge, list[UPPER]);
499 * The pending list isn't empty, take the first block to
503 list_del_init(&edge->list[UPPER]);
504 cur = edge->node[UPPER];
508 /* Finish the upper linkage of newly added edges/nodes */
509 ret = btrfs_backref_finish_upper_links(cache, node);
515 if (handle_useless_nodes(rc, node))
518 btrfs_backref_iter_free(iter);
519 btrfs_free_path(path);
521 btrfs_backref_error_cleanup(cache, node);
524 ASSERT(!node || !node->detached);
525 ASSERT(list_empty(&cache->useless_node) &&
526 list_empty(&cache->pending_edge));
531 * helper to add backref node for the newly created snapshot.
532 * the backref node is created by cloning backref node that
533 * corresponds to root of source tree
535 static int clone_backref_node(struct btrfs_trans_handle *trans,
536 struct reloc_control *rc,
537 struct btrfs_root *src,
538 struct btrfs_root *dest)
540 struct btrfs_root *reloc_root = src->reloc_root;
541 struct btrfs_backref_cache *cache = &rc->backref_cache;
542 struct btrfs_backref_node *node = NULL;
543 struct btrfs_backref_node *new_node;
544 struct btrfs_backref_edge *edge;
545 struct btrfs_backref_edge *new_edge;
546 struct rb_node *rb_node;
548 if (cache->last_trans > 0)
549 update_backref_cache(trans, cache);
551 rb_node = rb_simple_search(&cache->rb_root, src->commit_root->start);
553 node = rb_entry(rb_node, struct btrfs_backref_node, rb_node);
557 BUG_ON(node->new_bytenr != reloc_root->node->start);
561 rb_node = rb_simple_search(&cache->rb_root,
562 reloc_root->commit_root->start);
564 node = rb_entry(rb_node, struct btrfs_backref_node,
566 BUG_ON(node->detached);
573 new_node = btrfs_backref_alloc_node(cache, dest->node->start,
578 new_node->lowest = node->lowest;
579 new_node->checked = 1;
580 new_node->root = btrfs_grab_root(dest);
581 ASSERT(new_node->root);
584 list_for_each_entry(edge, &node->lower, list[UPPER]) {
585 new_edge = btrfs_backref_alloc_edge(cache);
589 btrfs_backref_link_edge(new_edge, edge->node[LOWER],
590 new_node, LINK_UPPER);
593 list_add_tail(&new_node->lower, &cache->leaves);
596 rb_node = rb_simple_insert(&cache->rb_root, new_node->bytenr,
599 btrfs_backref_panic(trans->fs_info, new_node->bytenr, -EEXIST);
601 if (!new_node->lowest) {
602 list_for_each_entry(new_edge, &new_node->lower, list[UPPER]) {
603 list_add_tail(&new_edge->list[LOWER],
604 &new_edge->node[LOWER]->upper);
609 while (!list_empty(&new_node->lower)) {
610 new_edge = list_entry(new_node->lower.next,
611 struct btrfs_backref_edge, list[UPPER]);
612 list_del(&new_edge->list[UPPER]);
613 btrfs_backref_free_edge(cache, new_edge);
615 btrfs_backref_free_node(cache, new_node);
620 * helper to add 'address of tree root -> reloc tree' mapping
622 static int __must_check __add_reloc_root(struct btrfs_root *root)
624 struct btrfs_fs_info *fs_info = root->fs_info;
625 struct rb_node *rb_node;
626 struct mapping_node *node;
627 struct reloc_control *rc = fs_info->reloc_ctl;
629 node = kmalloc(sizeof(*node), GFP_NOFS);
633 node->bytenr = root->commit_root->start;
636 spin_lock(&rc->reloc_root_tree.lock);
637 rb_node = rb_simple_insert(&rc->reloc_root_tree.rb_root,
638 node->bytenr, &node->rb_node);
639 spin_unlock(&rc->reloc_root_tree.lock);
641 btrfs_panic(fs_info, -EEXIST,
642 "Duplicate root found for start=%llu while inserting into relocation tree",
646 list_add_tail(&root->root_list, &rc->reloc_roots);
651 * helper to delete the 'address of tree root -> reloc tree'
654 static void __del_reloc_root(struct btrfs_root *root)
656 struct btrfs_fs_info *fs_info = root->fs_info;
657 struct rb_node *rb_node;
658 struct mapping_node *node = NULL;
659 struct reloc_control *rc = fs_info->reloc_ctl;
660 bool put_ref = false;
662 if (rc && root->node) {
663 spin_lock(&rc->reloc_root_tree.lock);
664 rb_node = rb_simple_search(&rc->reloc_root_tree.rb_root,
665 root->commit_root->start);
667 node = rb_entry(rb_node, struct mapping_node, rb_node);
668 rb_erase(&node->rb_node, &rc->reloc_root_tree.rb_root);
669 RB_CLEAR_NODE(&node->rb_node);
671 spin_unlock(&rc->reloc_root_tree.lock);
674 BUG_ON((struct btrfs_root *)node->data != root);
678 * We only put the reloc root here if it's on the list. There's a lot
679 * of places where the pattern is to splice the rc->reloc_roots, process
680 * the reloc roots, and then add the reloc root back onto
681 * rc->reloc_roots. If we call __del_reloc_root while it's off of the
682 * list we don't want the reference being dropped, because the guy
683 * messing with the list is in charge of the reference.
685 spin_lock(&fs_info->trans_lock);
686 if (!list_empty(&root->root_list)) {
688 list_del_init(&root->root_list);
690 spin_unlock(&fs_info->trans_lock);
692 btrfs_put_root(root);
697 * helper to update the 'address of tree root -> reloc tree'
700 static int __update_reloc_root(struct btrfs_root *root)
702 struct btrfs_fs_info *fs_info = root->fs_info;
703 struct rb_node *rb_node;
704 struct mapping_node *node = NULL;
705 struct reloc_control *rc = fs_info->reloc_ctl;
707 spin_lock(&rc->reloc_root_tree.lock);
708 rb_node = rb_simple_search(&rc->reloc_root_tree.rb_root,
709 root->commit_root->start);
711 node = rb_entry(rb_node, struct mapping_node, rb_node);
712 rb_erase(&node->rb_node, &rc->reloc_root_tree.rb_root);
714 spin_unlock(&rc->reloc_root_tree.lock);
718 BUG_ON((struct btrfs_root *)node->data != root);
720 spin_lock(&rc->reloc_root_tree.lock);
721 node->bytenr = root->node->start;
722 rb_node = rb_simple_insert(&rc->reloc_root_tree.rb_root,
723 node->bytenr, &node->rb_node);
724 spin_unlock(&rc->reloc_root_tree.lock);
726 btrfs_backref_panic(fs_info, node->bytenr, -EEXIST);
730 static struct btrfs_root *create_reloc_root(struct btrfs_trans_handle *trans,
731 struct btrfs_root *root, u64 objectid)
733 struct btrfs_fs_info *fs_info = root->fs_info;
734 struct btrfs_root *reloc_root;
735 struct extent_buffer *eb;
736 struct btrfs_root_item *root_item;
737 struct btrfs_key root_key;
740 root_item = kmalloc(sizeof(*root_item), GFP_NOFS);
743 root_key.objectid = BTRFS_TREE_RELOC_OBJECTID;
744 root_key.type = BTRFS_ROOT_ITEM_KEY;
745 root_key.offset = objectid;
747 if (root->root_key.objectid == objectid) {
750 /* called by btrfs_init_reloc_root */
751 ret = btrfs_copy_root(trans, root, root->commit_root, &eb,
752 BTRFS_TREE_RELOC_OBJECTID);
755 * Set the last_snapshot field to the generation of the commit
756 * root - like this ctree.c:btrfs_block_can_be_shared() behaves
757 * correctly (returns true) when the relocation root is created
758 * either inside the critical section of a transaction commit
759 * (through transaction.c:qgroup_account_snapshot()) and when
760 * it's created before the transaction commit is started.
762 commit_root_gen = btrfs_header_generation(root->commit_root);
763 btrfs_set_root_last_snapshot(&root->root_item, commit_root_gen);
766 * called by btrfs_reloc_post_snapshot_hook.
767 * the source tree is a reloc tree, all tree blocks
768 * modified after it was created have RELOC flag
769 * set in their headers. so it's OK to not update
770 * the 'last_snapshot'.
772 ret = btrfs_copy_root(trans, root, root->node, &eb,
773 BTRFS_TREE_RELOC_OBJECTID);
777 memcpy(root_item, &root->root_item, sizeof(*root_item));
778 btrfs_set_root_bytenr(root_item, eb->start);
779 btrfs_set_root_level(root_item, btrfs_header_level(eb));
780 btrfs_set_root_generation(root_item, trans->transid);
782 if (root->root_key.objectid == objectid) {
783 btrfs_set_root_refs(root_item, 0);
784 memset(&root_item->drop_progress, 0,
785 sizeof(struct btrfs_disk_key));
786 root_item->drop_level = 0;
789 btrfs_tree_unlock(eb);
790 free_extent_buffer(eb);
792 ret = btrfs_insert_root(trans, fs_info->tree_root,
793 &root_key, root_item);
797 reloc_root = btrfs_read_tree_root(fs_info->tree_root, &root_key);
798 BUG_ON(IS_ERR(reloc_root));
799 set_bit(BTRFS_ROOT_SHAREABLE, &reloc_root->state);
800 reloc_root->last_trans = trans->transid;
805 * create reloc tree for a given fs tree. reloc tree is just a
806 * snapshot of the fs tree with special root objectid.
808 * The reloc_root comes out of here with two references, one for
809 * root->reloc_root, and another for being on the rc->reloc_roots list.
811 int btrfs_init_reloc_root(struct btrfs_trans_handle *trans,
812 struct btrfs_root *root)
814 struct btrfs_fs_info *fs_info = root->fs_info;
815 struct btrfs_root *reloc_root;
816 struct reloc_control *rc = fs_info->reloc_ctl;
817 struct btrfs_block_rsv *rsv;
825 * The subvolume has reloc tree but the swap is finished, no need to
826 * create/update the dead reloc tree
828 if (reloc_root_is_dead(root))
832 * This is subtle but important. We do not do
833 * record_root_in_transaction for reloc roots, instead we record their
834 * corresponding fs root, and then here we update the last trans for the
835 * reloc root. This means that we have to do this for the entire life
836 * of the reloc root, regardless of which stage of the relocation we are
839 if (root->reloc_root) {
840 reloc_root = root->reloc_root;
841 reloc_root->last_trans = trans->transid;
846 * We are merging reloc roots, we do not need new reloc trees. Also
847 * reloc trees never need their own reloc tree.
849 if (!rc->create_reloc_tree ||
850 root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID)
853 if (!trans->reloc_reserved) {
854 rsv = trans->block_rsv;
855 trans->block_rsv = rc->block_rsv;
858 reloc_root = create_reloc_root(trans, root, root->root_key.objectid);
860 trans->block_rsv = rsv;
862 ret = __add_reloc_root(reloc_root);
864 root->reloc_root = btrfs_grab_root(reloc_root);
869 * update root item of reloc tree
871 int btrfs_update_reloc_root(struct btrfs_trans_handle *trans,
872 struct btrfs_root *root)
874 struct btrfs_fs_info *fs_info = root->fs_info;
875 struct btrfs_root *reloc_root;
876 struct btrfs_root_item *root_item;
879 if (!have_reloc_root(root))
882 reloc_root = root->reloc_root;
883 root_item = &reloc_root->root_item;
886 * We are probably ok here, but __del_reloc_root() will drop its ref of
887 * the root. We have the ref for root->reloc_root, but just in case
888 * hold it while we update the reloc root.
890 btrfs_grab_root(reloc_root);
892 /* root->reloc_root will stay until current relocation finished */
893 if (fs_info->reloc_ctl->merge_reloc_tree &&
894 btrfs_root_refs(root_item) == 0) {
895 set_bit(BTRFS_ROOT_DEAD_RELOC_TREE, &root->state);
897 * Mark the tree as dead before we change reloc_root so
898 * have_reloc_root will not touch it from now on.
901 __del_reloc_root(reloc_root);
904 if (reloc_root->commit_root != reloc_root->node) {
905 __update_reloc_root(reloc_root);
906 btrfs_set_root_node(root_item, reloc_root->node);
907 free_extent_buffer(reloc_root->commit_root);
908 reloc_root->commit_root = btrfs_root_node(reloc_root);
911 ret = btrfs_update_root(trans, fs_info->tree_root,
912 &reloc_root->root_key, root_item);
914 btrfs_put_root(reloc_root);
920 * helper to find first cached inode with inode number >= objectid
923 static struct inode *find_next_inode(struct btrfs_root *root, u64 objectid)
925 struct rb_node *node;
926 struct rb_node *prev;
927 struct btrfs_inode *entry;
930 spin_lock(&root->inode_lock);
932 node = root->inode_tree.rb_node;
936 entry = rb_entry(node, struct btrfs_inode, rb_node);
938 if (objectid < btrfs_ino(entry))
939 node = node->rb_left;
940 else if (objectid > btrfs_ino(entry))
941 node = node->rb_right;
947 entry = rb_entry(prev, struct btrfs_inode, rb_node);
948 if (objectid <= btrfs_ino(entry)) {
952 prev = rb_next(prev);
956 entry = rb_entry(node, struct btrfs_inode, rb_node);
957 inode = igrab(&entry->vfs_inode);
959 spin_unlock(&root->inode_lock);
963 objectid = btrfs_ino(entry) + 1;
964 if (cond_resched_lock(&root->inode_lock))
967 node = rb_next(node);
969 spin_unlock(&root->inode_lock);
974 * get new location of data
976 static int get_new_location(struct inode *reloc_inode, u64 *new_bytenr,
977 u64 bytenr, u64 num_bytes)
979 struct btrfs_root *root = BTRFS_I(reloc_inode)->root;
980 struct btrfs_path *path;
981 struct btrfs_file_extent_item *fi;
982 struct extent_buffer *leaf;
985 path = btrfs_alloc_path();
989 bytenr -= BTRFS_I(reloc_inode)->index_cnt;
990 ret = btrfs_lookup_file_extent(NULL, root, path,
991 btrfs_ino(BTRFS_I(reloc_inode)), bytenr, 0);
999 leaf = path->nodes[0];
1000 fi = btrfs_item_ptr(leaf, path->slots[0],
1001 struct btrfs_file_extent_item);
1003 BUG_ON(btrfs_file_extent_offset(leaf, fi) ||
1004 btrfs_file_extent_compression(leaf, fi) ||
1005 btrfs_file_extent_encryption(leaf, fi) ||
1006 btrfs_file_extent_other_encoding(leaf, fi));
1008 if (num_bytes != btrfs_file_extent_disk_num_bytes(leaf, fi)) {
1013 *new_bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
1016 btrfs_free_path(path);
1021 * update file extent items in the tree leaf to point to
1022 * the new locations.
1024 static noinline_for_stack
1025 int replace_file_extents(struct btrfs_trans_handle *trans,
1026 struct reloc_control *rc,
1027 struct btrfs_root *root,
1028 struct extent_buffer *leaf)
1030 struct btrfs_fs_info *fs_info = root->fs_info;
1031 struct btrfs_key key;
1032 struct btrfs_file_extent_item *fi;
1033 struct inode *inode = NULL;
1045 if (rc->stage != UPDATE_DATA_PTRS)
1048 /* reloc trees always use full backref */
1049 if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID)
1050 parent = leaf->start;
1054 nritems = btrfs_header_nritems(leaf);
1055 for (i = 0; i < nritems; i++) {
1056 struct btrfs_ref ref = { 0 };
1059 btrfs_item_key_to_cpu(leaf, &key, i);
1060 if (key.type != BTRFS_EXTENT_DATA_KEY)
1062 fi = btrfs_item_ptr(leaf, i, struct btrfs_file_extent_item);
1063 if (btrfs_file_extent_type(leaf, fi) ==
1064 BTRFS_FILE_EXTENT_INLINE)
1066 bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
1067 num_bytes = btrfs_file_extent_disk_num_bytes(leaf, fi);
1070 if (!in_range(bytenr, rc->block_group->start,
1071 rc->block_group->length))
1075 * if we are modifying block in fs tree, wait for readpage
1076 * to complete and drop the extent cache
1078 if (root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID) {
1080 inode = find_next_inode(root, key.objectid);
1082 } else if (inode && btrfs_ino(BTRFS_I(inode)) < key.objectid) {
1083 btrfs_add_delayed_iput(inode);
1084 inode = find_next_inode(root, key.objectid);
1086 if (inode && btrfs_ino(BTRFS_I(inode)) == key.objectid) {
1088 btrfs_file_extent_num_bytes(leaf, fi);
1089 WARN_ON(!IS_ALIGNED(key.offset,
1090 fs_info->sectorsize));
1091 WARN_ON(!IS_ALIGNED(end, fs_info->sectorsize));
1093 ret = try_lock_extent(&BTRFS_I(inode)->io_tree,
1098 btrfs_drop_extent_cache(BTRFS_I(inode),
1099 key.offset, end, 1);
1100 unlock_extent(&BTRFS_I(inode)->io_tree,
1105 ret = get_new_location(rc->data_inode, &new_bytenr,
1109 * Don't have to abort since we've not changed anything
1110 * in the file extent yet.
1115 btrfs_set_file_extent_disk_bytenr(leaf, fi, new_bytenr);
1118 key.offset -= btrfs_file_extent_offset(leaf, fi);
1119 btrfs_init_generic_ref(&ref, BTRFS_ADD_DELAYED_REF, new_bytenr,
1121 ref.real_root = root->root_key.objectid;
1122 btrfs_init_data_ref(&ref, btrfs_header_owner(leaf),
1123 key.objectid, key.offset);
1124 ret = btrfs_inc_extent_ref(trans, &ref);
1126 btrfs_abort_transaction(trans, ret);
1130 btrfs_init_generic_ref(&ref, BTRFS_DROP_DELAYED_REF, bytenr,
1132 ref.real_root = root->root_key.objectid;
1133 btrfs_init_data_ref(&ref, btrfs_header_owner(leaf),
1134 key.objectid, key.offset);
1135 ret = btrfs_free_extent(trans, &ref);
1137 btrfs_abort_transaction(trans, ret);
1142 btrfs_mark_buffer_dirty(leaf);
1144 btrfs_add_delayed_iput(inode);
1148 static noinline_for_stack
1149 int memcmp_node_keys(struct extent_buffer *eb, int slot,
1150 struct btrfs_path *path, int level)
1152 struct btrfs_disk_key key1;
1153 struct btrfs_disk_key key2;
1154 btrfs_node_key(eb, &key1, slot);
1155 btrfs_node_key(path->nodes[level], &key2, path->slots[level]);
1156 return memcmp(&key1, &key2, sizeof(key1));
1160 * try to replace tree blocks in fs tree with the new blocks
1161 * in reloc tree. tree blocks haven't been modified since the
1162 * reloc tree was create can be replaced.
1164 * if a block was replaced, level of the block + 1 is returned.
1165 * if no block got replaced, 0 is returned. if there are other
1166 * errors, a negative error number is returned.
1168 static noinline_for_stack
1169 int replace_path(struct btrfs_trans_handle *trans, struct reloc_control *rc,
1170 struct btrfs_root *dest, struct btrfs_root *src,
1171 struct btrfs_path *path, struct btrfs_key *next_key,
1172 int lowest_level, int max_level)
1174 struct btrfs_fs_info *fs_info = dest->fs_info;
1175 struct extent_buffer *eb;
1176 struct extent_buffer *parent;
1177 struct btrfs_ref ref = { 0 };
1178 struct btrfs_key key;
1190 BUG_ON(src->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID);
1191 BUG_ON(dest->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID);
1193 last_snapshot = btrfs_root_last_snapshot(&src->root_item);
1195 slot = path->slots[lowest_level];
1196 btrfs_node_key_to_cpu(path->nodes[lowest_level], &key, slot);
1198 eb = btrfs_lock_root_node(dest);
1199 btrfs_set_lock_blocking_write(eb);
1200 level = btrfs_header_level(eb);
1202 if (level < lowest_level) {
1203 btrfs_tree_unlock(eb);
1204 free_extent_buffer(eb);
1209 ret = btrfs_cow_block(trans, dest, eb, NULL, 0, &eb,
1213 btrfs_set_lock_blocking_write(eb);
1216 next_key->objectid = (u64)-1;
1217 next_key->type = (u8)-1;
1218 next_key->offset = (u64)-1;
1223 struct btrfs_key first_key;
1225 level = btrfs_header_level(parent);
1226 BUG_ON(level < lowest_level);
1228 ret = btrfs_bin_search(parent, &key, &slot);
1231 if (ret && slot > 0)
1234 if (next_key && slot + 1 < btrfs_header_nritems(parent))
1235 btrfs_node_key_to_cpu(parent, next_key, slot + 1);
1237 old_bytenr = btrfs_node_blockptr(parent, slot);
1238 blocksize = fs_info->nodesize;
1239 old_ptr_gen = btrfs_node_ptr_generation(parent, slot);
1240 btrfs_node_key_to_cpu(parent, &first_key, slot);
1242 if (level <= max_level) {
1243 eb = path->nodes[level];
1244 new_bytenr = btrfs_node_blockptr(eb,
1245 path->slots[level]);
1246 new_ptr_gen = btrfs_node_ptr_generation(eb,
1247 path->slots[level]);
1253 if (WARN_ON(new_bytenr > 0 && new_bytenr == old_bytenr)) {
1258 if (new_bytenr == 0 || old_ptr_gen > last_snapshot ||
1259 memcmp_node_keys(parent, slot, path, level)) {
1260 if (level <= lowest_level) {
1265 eb = read_tree_block(fs_info, old_bytenr, old_ptr_gen,
1266 level - 1, &first_key);
1270 } else if (!extent_buffer_uptodate(eb)) {
1272 free_extent_buffer(eb);
1275 btrfs_tree_lock(eb);
1277 ret = btrfs_cow_block(trans, dest, eb, parent,
1282 btrfs_set_lock_blocking_write(eb);
1284 btrfs_tree_unlock(parent);
1285 free_extent_buffer(parent);
1292 btrfs_tree_unlock(parent);
1293 free_extent_buffer(parent);
1298 btrfs_node_key_to_cpu(path->nodes[level], &key,
1299 path->slots[level]);
1300 btrfs_release_path(path);
1302 path->lowest_level = level;
1303 ret = btrfs_search_slot(trans, src, &key, path, 0, 1);
1304 path->lowest_level = 0;
1308 * Info qgroup to trace both subtrees.
1310 * We must trace both trees.
1311 * 1) Tree reloc subtree
1312 * If not traced, we will leak data numbers
1314 * If not traced, we will double count old data
1316 * We don't scan the subtree right now, but only record
1317 * the swapped tree blocks.
1318 * The real subtree rescan is delayed until we have new
1319 * CoW on the subtree root node before transaction commit.
1321 ret = btrfs_qgroup_add_swapped_blocks(trans, dest,
1322 rc->block_group, parent, slot,
1323 path->nodes[level], path->slots[level],
1328 * swap blocks in fs tree and reloc tree.
1330 btrfs_set_node_blockptr(parent, slot, new_bytenr);
1331 btrfs_set_node_ptr_generation(parent, slot, new_ptr_gen);
1332 btrfs_mark_buffer_dirty(parent);
1334 btrfs_set_node_blockptr(path->nodes[level],
1335 path->slots[level], old_bytenr);
1336 btrfs_set_node_ptr_generation(path->nodes[level],
1337 path->slots[level], old_ptr_gen);
1338 btrfs_mark_buffer_dirty(path->nodes[level]);
1340 btrfs_init_generic_ref(&ref, BTRFS_ADD_DELAYED_REF, old_bytenr,
1341 blocksize, path->nodes[level]->start);
1342 ref.skip_qgroup = true;
1343 btrfs_init_tree_ref(&ref, level - 1, src->root_key.objectid);
1344 ret = btrfs_inc_extent_ref(trans, &ref);
1346 btrfs_init_generic_ref(&ref, BTRFS_ADD_DELAYED_REF, new_bytenr,
1348 ref.skip_qgroup = true;
1349 btrfs_init_tree_ref(&ref, level - 1, dest->root_key.objectid);
1350 ret = btrfs_inc_extent_ref(trans, &ref);
1353 btrfs_init_generic_ref(&ref, BTRFS_DROP_DELAYED_REF, new_bytenr,
1354 blocksize, path->nodes[level]->start);
1355 btrfs_init_tree_ref(&ref, level - 1, src->root_key.objectid);
1356 ref.skip_qgroup = true;
1357 ret = btrfs_free_extent(trans, &ref);
1360 btrfs_init_generic_ref(&ref, BTRFS_DROP_DELAYED_REF, old_bytenr,
1362 btrfs_init_tree_ref(&ref, level - 1, dest->root_key.objectid);
1363 ref.skip_qgroup = true;
1364 ret = btrfs_free_extent(trans, &ref);
1367 btrfs_unlock_up_safe(path, 0);
1372 btrfs_tree_unlock(parent);
1373 free_extent_buffer(parent);
1378 * helper to find next relocated block in reloc tree
1380 static noinline_for_stack
1381 int walk_up_reloc_tree(struct btrfs_root *root, struct btrfs_path *path,
1384 struct extent_buffer *eb;
1389 last_snapshot = btrfs_root_last_snapshot(&root->root_item);
1391 for (i = 0; i < *level; i++) {
1392 free_extent_buffer(path->nodes[i]);
1393 path->nodes[i] = NULL;
1396 for (i = *level; i < BTRFS_MAX_LEVEL && path->nodes[i]; i++) {
1397 eb = path->nodes[i];
1398 nritems = btrfs_header_nritems(eb);
1399 while (path->slots[i] + 1 < nritems) {
1401 if (btrfs_node_ptr_generation(eb, path->slots[i]) <=
1408 free_extent_buffer(path->nodes[i]);
1409 path->nodes[i] = NULL;
1415 * walk down reloc tree to find relocated block of lowest level
1417 static noinline_for_stack
1418 int walk_down_reloc_tree(struct btrfs_root *root, struct btrfs_path *path,
1421 struct btrfs_fs_info *fs_info = root->fs_info;
1422 struct extent_buffer *eb = NULL;
1429 last_snapshot = btrfs_root_last_snapshot(&root->root_item);
1431 for (i = *level; i > 0; i--) {
1432 struct btrfs_key first_key;
1434 eb = path->nodes[i];
1435 nritems = btrfs_header_nritems(eb);
1436 while (path->slots[i] < nritems) {
1437 ptr_gen = btrfs_node_ptr_generation(eb, path->slots[i]);
1438 if (ptr_gen > last_snapshot)
1442 if (path->slots[i] >= nritems) {
1453 bytenr = btrfs_node_blockptr(eb, path->slots[i]);
1454 btrfs_node_key_to_cpu(eb, &first_key, path->slots[i]);
1455 eb = read_tree_block(fs_info, bytenr, ptr_gen, i - 1,
1459 } else if (!extent_buffer_uptodate(eb)) {
1460 free_extent_buffer(eb);
1463 BUG_ON(btrfs_header_level(eb) != i - 1);
1464 path->nodes[i - 1] = eb;
1465 path->slots[i - 1] = 0;
1471 * invalidate extent cache for file extents whose key in range of
1472 * [min_key, max_key)
1474 static int invalidate_extent_cache(struct btrfs_root *root,
1475 struct btrfs_key *min_key,
1476 struct btrfs_key *max_key)
1478 struct btrfs_fs_info *fs_info = root->fs_info;
1479 struct inode *inode = NULL;
1484 objectid = min_key->objectid;
1489 if (objectid > max_key->objectid)
1492 inode = find_next_inode(root, objectid);
1495 ino = btrfs_ino(BTRFS_I(inode));
1497 if (ino > max_key->objectid) {
1503 if (!S_ISREG(inode->i_mode))
1506 if (unlikely(min_key->objectid == ino)) {
1507 if (min_key->type > BTRFS_EXTENT_DATA_KEY)
1509 if (min_key->type < BTRFS_EXTENT_DATA_KEY)
1512 start = min_key->offset;
1513 WARN_ON(!IS_ALIGNED(start, fs_info->sectorsize));
1519 if (unlikely(max_key->objectid == ino)) {
1520 if (max_key->type < BTRFS_EXTENT_DATA_KEY)
1522 if (max_key->type > BTRFS_EXTENT_DATA_KEY) {
1525 if (max_key->offset == 0)
1527 end = max_key->offset;
1528 WARN_ON(!IS_ALIGNED(end, fs_info->sectorsize));
1535 /* the lock_extent waits for readpage to complete */
1536 lock_extent(&BTRFS_I(inode)->io_tree, start, end);
1537 btrfs_drop_extent_cache(BTRFS_I(inode), start, end, 1);
1538 unlock_extent(&BTRFS_I(inode)->io_tree, start, end);
1543 static int find_next_key(struct btrfs_path *path, int level,
1544 struct btrfs_key *key)
1547 while (level < BTRFS_MAX_LEVEL) {
1548 if (!path->nodes[level])
1550 if (path->slots[level] + 1 <
1551 btrfs_header_nritems(path->nodes[level])) {
1552 btrfs_node_key_to_cpu(path->nodes[level], key,
1553 path->slots[level] + 1);
1562 * Insert current subvolume into reloc_control::dirty_subvol_roots
1564 static void insert_dirty_subvol(struct btrfs_trans_handle *trans,
1565 struct reloc_control *rc,
1566 struct btrfs_root *root)
1568 struct btrfs_root *reloc_root = root->reloc_root;
1569 struct btrfs_root_item *reloc_root_item;
1571 /* @root must be a subvolume tree root with a valid reloc tree */
1572 ASSERT(root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID);
1575 reloc_root_item = &reloc_root->root_item;
1576 memset(&reloc_root_item->drop_progress, 0,
1577 sizeof(reloc_root_item->drop_progress));
1578 reloc_root_item->drop_level = 0;
1579 btrfs_set_root_refs(reloc_root_item, 0);
1580 btrfs_update_reloc_root(trans, root);
1582 if (list_empty(&root->reloc_dirty_list)) {
1583 btrfs_grab_root(root);
1584 list_add_tail(&root->reloc_dirty_list, &rc->dirty_subvol_roots);
1588 static int clean_dirty_subvols(struct reloc_control *rc)
1590 struct btrfs_root *root;
1591 struct btrfs_root *next;
1595 list_for_each_entry_safe(root, next, &rc->dirty_subvol_roots,
1597 if (root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID) {
1598 /* Merged subvolume, cleanup its reloc root */
1599 struct btrfs_root *reloc_root = root->reloc_root;
1601 list_del_init(&root->reloc_dirty_list);
1602 root->reloc_root = NULL;
1604 * Need barrier to ensure clear_bit() only happens after
1605 * root->reloc_root = NULL. Pairs with have_reloc_root.
1608 clear_bit(BTRFS_ROOT_DEAD_RELOC_TREE, &root->state);
1611 * btrfs_drop_snapshot drops our ref we hold for
1612 * ->reloc_root. If it fails however we must
1613 * drop the ref ourselves.
1615 ret2 = btrfs_drop_snapshot(reloc_root, 0, 1);
1617 btrfs_put_root(reloc_root);
1622 btrfs_put_root(root);
1624 /* Orphan reloc tree, just clean it up */
1625 ret2 = btrfs_drop_snapshot(root, 0, 1);
1627 btrfs_put_root(root);
1637 * merge the relocated tree blocks in reloc tree with corresponding
1640 static noinline_for_stack int merge_reloc_root(struct reloc_control *rc,
1641 struct btrfs_root *root)
1643 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
1644 struct btrfs_key key;
1645 struct btrfs_key next_key;
1646 struct btrfs_trans_handle *trans = NULL;
1647 struct btrfs_root *reloc_root;
1648 struct btrfs_root_item *root_item;
1649 struct btrfs_path *path;
1650 struct extent_buffer *leaf;
1658 path = btrfs_alloc_path();
1661 path->reada = READA_FORWARD;
1663 reloc_root = root->reloc_root;
1664 root_item = &reloc_root->root_item;
1666 if (btrfs_disk_key_objectid(&root_item->drop_progress) == 0) {
1667 level = btrfs_root_level(root_item);
1668 atomic_inc(&reloc_root->node->refs);
1669 path->nodes[level] = reloc_root->node;
1670 path->slots[level] = 0;
1672 btrfs_disk_key_to_cpu(&key, &root_item->drop_progress);
1674 level = root_item->drop_level;
1676 path->lowest_level = level;
1677 ret = btrfs_search_slot(NULL, reloc_root, &key, path, 0, 0);
1678 path->lowest_level = 0;
1680 btrfs_free_path(path);
1684 btrfs_node_key_to_cpu(path->nodes[level], &next_key,
1685 path->slots[level]);
1686 WARN_ON(memcmp(&key, &next_key, sizeof(key)));
1688 btrfs_unlock_up_safe(path, 0);
1692 * In merge_reloc_root(), we modify the upper level pointer to swap the
1693 * tree blocks between reloc tree and subvolume tree. Thus for tree
1694 * block COW, we COW at most from level 1 to root level for each tree.
1696 * Thus the needed metadata size is at most root_level * nodesize,
1697 * and * 2 since we have two trees to COW.
1699 min_reserved = fs_info->nodesize * btrfs_root_level(root_item) * 2;
1700 memset(&next_key, 0, sizeof(next_key));
1703 ret = btrfs_block_rsv_refill(root, rc->block_rsv, min_reserved,
1704 BTRFS_RESERVE_FLUSH_LIMIT);
1709 trans = btrfs_start_transaction(root, 0);
1710 if (IS_ERR(trans)) {
1711 err = PTR_ERR(trans);
1717 * At this point we no longer have a reloc_control, so we can't
1718 * depend on btrfs_init_reloc_root to update our last_trans.
1720 * But that's ok, we started the trans handle on our
1721 * corresponding fs_root, which means it's been added to the
1722 * dirty list. At commit time we'll still call
1723 * btrfs_update_reloc_root() and update our root item
1726 reloc_root->last_trans = trans->transid;
1727 trans->block_rsv = rc->block_rsv;
1732 ret = walk_down_reloc_tree(reloc_root, path, &level);
1740 if (!find_next_key(path, level, &key) &&
1741 btrfs_comp_cpu_keys(&next_key, &key) >= 0) {
1744 ret = replace_path(trans, rc, root, reloc_root, path,
1745 &next_key, level, max_level);
1754 btrfs_node_key_to_cpu(path->nodes[level], &key,
1755 path->slots[level]);
1759 ret = walk_up_reloc_tree(reloc_root, path, &level);
1765 * save the merging progress in the drop_progress.
1766 * this is OK since root refs == 1 in this case.
1768 btrfs_node_key(path->nodes[level], &root_item->drop_progress,
1769 path->slots[level]);
1770 root_item->drop_level = level;
1772 btrfs_end_transaction_throttle(trans);
1775 btrfs_btree_balance_dirty(fs_info);
1777 if (replaced && rc->stage == UPDATE_DATA_PTRS)
1778 invalidate_extent_cache(root, &key, &next_key);
1782 * handle the case only one block in the fs tree need to be
1783 * relocated and the block is tree root.
1785 leaf = btrfs_lock_root_node(root);
1786 ret = btrfs_cow_block(trans, root, leaf, NULL, 0, &leaf,
1788 btrfs_tree_unlock(leaf);
1789 free_extent_buffer(leaf);
1793 btrfs_free_path(path);
1796 insert_dirty_subvol(trans, rc, root);
1799 btrfs_end_transaction_throttle(trans);
1801 btrfs_btree_balance_dirty(fs_info);
1803 if (replaced && rc->stage == UPDATE_DATA_PTRS)
1804 invalidate_extent_cache(root, &key, &next_key);
1809 static noinline_for_stack
1810 int prepare_to_merge(struct reloc_control *rc, int err)
1812 struct btrfs_root *root = rc->extent_root;
1813 struct btrfs_fs_info *fs_info = root->fs_info;
1814 struct btrfs_root *reloc_root;
1815 struct btrfs_trans_handle *trans;
1816 LIST_HEAD(reloc_roots);
1820 mutex_lock(&fs_info->reloc_mutex);
1821 rc->merging_rsv_size += fs_info->nodesize * (BTRFS_MAX_LEVEL - 1) * 2;
1822 rc->merging_rsv_size += rc->nodes_relocated * 2;
1823 mutex_unlock(&fs_info->reloc_mutex);
1827 num_bytes = rc->merging_rsv_size;
1828 ret = btrfs_block_rsv_add(root, rc->block_rsv, num_bytes,
1829 BTRFS_RESERVE_FLUSH_ALL);
1834 trans = btrfs_join_transaction(rc->extent_root);
1835 if (IS_ERR(trans)) {
1837 btrfs_block_rsv_release(fs_info, rc->block_rsv,
1839 return PTR_ERR(trans);
1843 if (num_bytes != rc->merging_rsv_size) {
1844 btrfs_end_transaction(trans);
1845 btrfs_block_rsv_release(fs_info, rc->block_rsv,
1851 rc->merge_reloc_tree = 1;
1853 while (!list_empty(&rc->reloc_roots)) {
1854 reloc_root = list_entry(rc->reloc_roots.next,
1855 struct btrfs_root, root_list);
1856 list_del_init(&reloc_root->root_list);
1858 root = btrfs_get_fs_root(fs_info, reloc_root->root_key.offset,
1860 BUG_ON(IS_ERR(root));
1861 BUG_ON(root->reloc_root != reloc_root);
1864 * set reference count to 1, so btrfs_recover_relocation
1865 * knows it should resumes merging
1868 btrfs_set_root_refs(&reloc_root->root_item, 1);
1869 btrfs_update_reloc_root(trans, root);
1871 list_add(&reloc_root->root_list, &reloc_roots);
1872 btrfs_put_root(root);
1875 list_splice(&reloc_roots, &rc->reloc_roots);
1878 btrfs_commit_transaction(trans);
1880 btrfs_end_transaction(trans);
1884 static noinline_for_stack
1885 void free_reloc_roots(struct list_head *list)
1887 struct btrfs_root *reloc_root, *tmp;
1889 list_for_each_entry_safe(reloc_root, tmp, list, root_list)
1890 __del_reloc_root(reloc_root);
1893 static noinline_for_stack
1894 void merge_reloc_roots(struct reloc_control *rc)
1896 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
1897 struct btrfs_root *root;
1898 struct btrfs_root *reloc_root;
1899 LIST_HEAD(reloc_roots);
1903 root = rc->extent_root;
1906 * this serializes us with btrfs_record_root_in_transaction,
1907 * we have to make sure nobody is in the middle of
1908 * adding their roots to the list while we are
1911 mutex_lock(&fs_info->reloc_mutex);
1912 list_splice_init(&rc->reloc_roots, &reloc_roots);
1913 mutex_unlock(&fs_info->reloc_mutex);
1915 while (!list_empty(&reloc_roots)) {
1917 reloc_root = list_entry(reloc_roots.next,
1918 struct btrfs_root, root_list);
1920 root = btrfs_get_fs_root(fs_info, reloc_root->root_key.offset,
1922 if (btrfs_root_refs(&reloc_root->root_item) > 0) {
1923 BUG_ON(IS_ERR(root));
1924 BUG_ON(root->reloc_root != reloc_root);
1925 ret = merge_reloc_root(rc, root);
1926 btrfs_put_root(root);
1928 if (list_empty(&reloc_root->root_list))
1929 list_add_tail(&reloc_root->root_list,
1934 if (!IS_ERR(root)) {
1935 if (root->reloc_root == reloc_root) {
1936 root->reloc_root = NULL;
1937 btrfs_put_root(reloc_root);
1939 clear_bit(BTRFS_ROOT_DEAD_RELOC_TREE,
1941 btrfs_put_root(root);
1944 list_del_init(&reloc_root->root_list);
1945 /* Don't forget to queue this reloc root for cleanup */
1946 list_add_tail(&reloc_root->reloc_dirty_list,
1947 &rc->dirty_subvol_roots);
1957 btrfs_handle_fs_error(fs_info, ret, NULL);
1958 free_reloc_roots(&reloc_roots);
1960 /* new reloc root may be added */
1961 mutex_lock(&fs_info->reloc_mutex);
1962 list_splice_init(&rc->reloc_roots, &reloc_roots);
1963 mutex_unlock(&fs_info->reloc_mutex);
1964 free_reloc_roots(&reloc_roots);
1970 * BUG_ON(!RB_EMPTY_ROOT(&rc->reloc_root_tree.rb_root));
1972 * here, but it's wrong. If we fail to start the transaction in
1973 * prepare_to_merge() we will have only 0 ref reloc roots, none of which
1974 * have actually been removed from the reloc_root_tree rb tree. This is
1975 * fine because we're bailing here, and we hold a reference on the root
1976 * for the list that holds it, so these roots will be cleaned up when we
1977 * do the reloc_dirty_list afterwards. Meanwhile the root->reloc_root
1978 * will be cleaned up on unmount.
1980 * The remaining nodes will be cleaned up by free_reloc_control.
1984 static void free_block_list(struct rb_root *blocks)
1986 struct tree_block *block;
1987 struct rb_node *rb_node;
1988 while ((rb_node = rb_first(blocks))) {
1989 block = rb_entry(rb_node, struct tree_block, rb_node);
1990 rb_erase(rb_node, blocks);
1995 static int record_reloc_root_in_trans(struct btrfs_trans_handle *trans,
1996 struct btrfs_root *reloc_root)
1998 struct btrfs_fs_info *fs_info = reloc_root->fs_info;
1999 struct btrfs_root *root;
2002 if (reloc_root->last_trans == trans->transid)
2005 root = btrfs_get_fs_root(fs_info, reloc_root->root_key.offset, false);
2006 BUG_ON(IS_ERR(root));
2007 BUG_ON(root->reloc_root != reloc_root);
2008 ret = btrfs_record_root_in_trans(trans, root);
2009 btrfs_put_root(root);
2014 static noinline_for_stack
2015 struct btrfs_root *select_reloc_root(struct btrfs_trans_handle *trans,
2016 struct reloc_control *rc,
2017 struct btrfs_backref_node *node,
2018 struct btrfs_backref_edge *edges[])
2020 struct btrfs_backref_node *next;
2021 struct btrfs_root *root;
2027 next = walk_up_backref(next, edges, &index);
2030 BUG_ON(!test_bit(BTRFS_ROOT_SHAREABLE, &root->state));
2032 if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID) {
2033 record_reloc_root_in_trans(trans, root);
2037 btrfs_record_root_in_trans(trans, root);
2038 root = root->reloc_root;
2040 if (next->new_bytenr != root->node->start) {
2041 BUG_ON(next->new_bytenr);
2042 BUG_ON(!list_empty(&next->list));
2043 next->new_bytenr = root->node->start;
2044 btrfs_put_root(next->root);
2045 next->root = btrfs_grab_root(root);
2047 list_add_tail(&next->list,
2048 &rc->backref_cache.changed);
2049 mark_block_processed(rc, next);
2055 next = walk_down_backref(edges, &index);
2056 if (!next || next->level <= node->level)
2063 /* setup backref node path for btrfs_reloc_cow_block */
2065 rc->backref_cache.path[next->level] = next;
2068 next = edges[index]->node[UPPER];
2074 * Select a tree root for relocation.
2076 * Return NULL if the block is not shareable. We should use do_relocation() in
2079 * Return a tree root pointer if the block is shareable.
2080 * Return -ENOENT if the block is root of reloc tree.
2082 static noinline_for_stack
2083 struct btrfs_root *select_one_root(struct btrfs_backref_node *node)
2085 struct btrfs_backref_node *next;
2086 struct btrfs_root *root;
2087 struct btrfs_root *fs_root = NULL;
2088 struct btrfs_backref_edge *edges[BTRFS_MAX_LEVEL - 1];
2094 next = walk_up_backref(next, edges, &index);
2098 /* No other choice for non-shareable tree */
2099 if (!test_bit(BTRFS_ROOT_SHAREABLE, &root->state))
2102 if (root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID)
2108 next = walk_down_backref(edges, &index);
2109 if (!next || next->level <= node->level)
2114 return ERR_PTR(-ENOENT);
2118 static noinline_for_stack
2119 u64 calcu_metadata_size(struct reloc_control *rc,
2120 struct btrfs_backref_node *node, int reserve)
2122 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
2123 struct btrfs_backref_node *next = node;
2124 struct btrfs_backref_edge *edge;
2125 struct btrfs_backref_edge *edges[BTRFS_MAX_LEVEL - 1];
2129 BUG_ON(reserve && node->processed);
2134 if (next->processed && (reserve || next != node))
2137 num_bytes += fs_info->nodesize;
2139 if (list_empty(&next->upper))
2142 edge = list_entry(next->upper.next,
2143 struct btrfs_backref_edge, list[LOWER]);
2144 edges[index++] = edge;
2145 next = edge->node[UPPER];
2147 next = walk_down_backref(edges, &index);
2152 static int reserve_metadata_space(struct btrfs_trans_handle *trans,
2153 struct reloc_control *rc,
2154 struct btrfs_backref_node *node)
2156 struct btrfs_root *root = rc->extent_root;
2157 struct btrfs_fs_info *fs_info = root->fs_info;
2162 num_bytes = calcu_metadata_size(rc, node, 1) * 2;
2164 trans->block_rsv = rc->block_rsv;
2165 rc->reserved_bytes += num_bytes;
2168 * We are under a transaction here so we can only do limited flushing.
2169 * If we get an enospc just kick back -EAGAIN so we know to drop the
2170 * transaction and try to refill when we can flush all the things.
2172 ret = btrfs_block_rsv_refill(root, rc->block_rsv, num_bytes,
2173 BTRFS_RESERVE_FLUSH_LIMIT);
2175 tmp = fs_info->nodesize * RELOCATION_RESERVED_NODES;
2176 while (tmp <= rc->reserved_bytes)
2179 * only one thread can access block_rsv at this point,
2180 * so we don't need hold lock to protect block_rsv.
2181 * we expand more reservation size here to allow enough
2182 * space for relocation and we will return earlier in
2185 rc->block_rsv->size = tmp + fs_info->nodesize *
2186 RELOCATION_RESERVED_NODES;
2194 * relocate a block tree, and then update pointers in upper level
2195 * blocks that reference the block to point to the new location.
2197 * if called by link_to_upper, the block has already been relocated.
2198 * in that case this function just updates pointers.
2200 static int do_relocation(struct btrfs_trans_handle *trans,
2201 struct reloc_control *rc,
2202 struct btrfs_backref_node *node,
2203 struct btrfs_key *key,
2204 struct btrfs_path *path, int lowest)
2206 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
2207 struct btrfs_backref_node *upper;
2208 struct btrfs_backref_edge *edge;
2209 struct btrfs_backref_edge *edges[BTRFS_MAX_LEVEL - 1];
2210 struct btrfs_root *root;
2211 struct extent_buffer *eb;
2219 BUG_ON(lowest && node->eb);
2221 path->lowest_level = node->level + 1;
2222 rc->backref_cache.path[node->level] = node;
2223 list_for_each_entry(edge, &node->upper, list[LOWER]) {
2224 struct btrfs_key first_key;
2225 struct btrfs_ref ref = { 0 };
2229 upper = edge->node[UPPER];
2230 root = select_reloc_root(trans, rc, upper, edges);
2233 if (upper->eb && !upper->locked) {
2235 ret = btrfs_bin_search(upper->eb, key, &slot);
2241 bytenr = btrfs_node_blockptr(upper->eb, slot);
2242 if (node->eb->start == bytenr)
2245 btrfs_backref_drop_node_buffer(upper);
2249 ret = btrfs_search_slot(trans, root, key, path, 0, 1);
2256 btrfs_release_path(path);
2261 upper->eb = path->nodes[upper->level];
2262 path->nodes[upper->level] = NULL;
2264 BUG_ON(upper->eb != path->nodes[upper->level]);
2268 path->locks[upper->level] = 0;
2270 slot = path->slots[upper->level];
2271 btrfs_release_path(path);
2273 ret = btrfs_bin_search(upper->eb, key, &slot);
2281 bytenr = btrfs_node_blockptr(upper->eb, slot);
2283 if (bytenr != node->bytenr) {
2284 btrfs_err(root->fs_info,
2285 "lowest leaf/node mismatch: bytenr %llu node->bytenr %llu slot %d upper %llu",
2286 bytenr, node->bytenr, slot,
2292 if (node->eb->start == bytenr)
2296 blocksize = root->fs_info->nodesize;
2297 generation = btrfs_node_ptr_generation(upper->eb, slot);
2298 btrfs_node_key_to_cpu(upper->eb, &first_key, slot);
2299 eb = read_tree_block(fs_info, bytenr, generation,
2300 upper->level - 1, &first_key);
2304 } else if (!extent_buffer_uptodate(eb)) {
2305 free_extent_buffer(eb);
2309 btrfs_tree_lock(eb);
2310 btrfs_set_lock_blocking_write(eb);
2313 ret = btrfs_cow_block(trans, root, eb, upper->eb,
2314 slot, &eb, BTRFS_NESTING_COW);
2315 btrfs_tree_unlock(eb);
2316 free_extent_buffer(eb);
2321 BUG_ON(node->eb != eb);
2323 btrfs_set_node_blockptr(upper->eb, slot,
2325 btrfs_set_node_ptr_generation(upper->eb, slot,
2327 btrfs_mark_buffer_dirty(upper->eb);
2329 btrfs_init_generic_ref(&ref, BTRFS_ADD_DELAYED_REF,
2330 node->eb->start, blocksize,
2332 ref.real_root = root->root_key.objectid;
2333 btrfs_init_tree_ref(&ref, node->level,
2334 btrfs_header_owner(upper->eb));
2335 ret = btrfs_inc_extent_ref(trans, &ref);
2338 ret = btrfs_drop_subtree(trans, root, eb, upper->eb);
2342 if (!upper->pending)
2343 btrfs_backref_drop_node_buffer(upper);
2345 btrfs_backref_unlock_node_buffer(upper);
2350 if (!err && node->pending) {
2351 btrfs_backref_drop_node_buffer(node);
2352 list_move_tail(&node->list, &rc->backref_cache.changed);
2356 path->lowest_level = 0;
2357 BUG_ON(err == -ENOSPC);
2361 static int link_to_upper(struct btrfs_trans_handle *trans,
2362 struct reloc_control *rc,
2363 struct btrfs_backref_node *node,
2364 struct btrfs_path *path)
2366 struct btrfs_key key;
2368 btrfs_node_key_to_cpu(node->eb, &key, 0);
2369 return do_relocation(trans, rc, node, &key, path, 0);
2372 static int finish_pending_nodes(struct btrfs_trans_handle *trans,
2373 struct reloc_control *rc,
2374 struct btrfs_path *path, int err)
2377 struct btrfs_backref_cache *cache = &rc->backref_cache;
2378 struct btrfs_backref_node *node;
2382 for (level = 0; level < BTRFS_MAX_LEVEL; level++) {
2383 while (!list_empty(&cache->pending[level])) {
2384 node = list_entry(cache->pending[level].next,
2385 struct btrfs_backref_node, list);
2386 list_move_tail(&node->list, &list);
2387 BUG_ON(!node->pending);
2390 ret = link_to_upper(trans, rc, node, path);
2395 list_splice_init(&list, &cache->pending[level]);
2401 * mark a block and all blocks directly/indirectly reference the block
2404 static void update_processed_blocks(struct reloc_control *rc,
2405 struct btrfs_backref_node *node)
2407 struct btrfs_backref_node *next = node;
2408 struct btrfs_backref_edge *edge;
2409 struct btrfs_backref_edge *edges[BTRFS_MAX_LEVEL - 1];
2415 if (next->processed)
2418 mark_block_processed(rc, next);
2420 if (list_empty(&next->upper))
2423 edge = list_entry(next->upper.next,
2424 struct btrfs_backref_edge, list[LOWER]);
2425 edges[index++] = edge;
2426 next = edge->node[UPPER];
2428 next = walk_down_backref(edges, &index);
2432 static int tree_block_processed(u64 bytenr, struct reloc_control *rc)
2434 u32 blocksize = rc->extent_root->fs_info->nodesize;
2436 if (test_range_bit(&rc->processed_blocks, bytenr,
2437 bytenr + blocksize - 1, EXTENT_DIRTY, 1, NULL))
2442 static int get_tree_block_key(struct btrfs_fs_info *fs_info,
2443 struct tree_block *block)
2445 struct extent_buffer *eb;
2447 eb = read_tree_block(fs_info, block->bytenr, block->key.offset,
2448 block->level, NULL);
2451 } else if (!extent_buffer_uptodate(eb)) {
2452 free_extent_buffer(eb);
2455 if (block->level == 0)
2456 btrfs_item_key_to_cpu(eb, &block->key, 0);
2458 btrfs_node_key_to_cpu(eb, &block->key, 0);
2459 free_extent_buffer(eb);
2460 block->key_ready = 1;
2465 * helper function to relocate a tree block
2467 static int relocate_tree_block(struct btrfs_trans_handle *trans,
2468 struct reloc_control *rc,
2469 struct btrfs_backref_node *node,
2470 struct btrfs_key *key,
2471 struct btrfs_path *path)
2473 struct btrfs_root *root;
2480 * If we fail here we want to drop our backref_node because we are going
2481 * to start over and regenerate the tree for it.
2483 ret = reserve_metadata_space(trans, rc, node);
2487 BUG_ON(node->processed);
2488 root = select_one_root(node);
2489 if (root == ERR_PTR(-ENOENT)) {
2490 update_processed_blocks(rc, node);
2495 if (test_bit(BTRFS_ROOT_SHAREABLE, &root->state)) {
2496 BUG_ON(node->new_bytenr);
2497 BUG_ON(!list_empty(&node->list));
2498 btrfs_record_root_in_trans(trans, root);
2499 root = root->reloc_root;
2500 node->new_bytenr = root->node->start;
2501 btrfs_put_root(node->root);
2502 node->root = btrfs_grab_root(root);
2504 list_add_tail(&node->list, &rc->backref_cache.changed);
2506 path->lowest_level = node->level;
2507 ret = btrfs_search_slot(trans, root, key, path, 0, 1);
2508 btrfs_release_path(path);
2513 update_processed_blocks(rc, node);
2515 ret = do_relocation(trans, rc, node, key, path, 1);
2518 if (ret || node->level == 0 || node->cowonly)
2519 btrfs_backref_cleanup_node(&rc->backref_cache, node);
2524 * relocate a list of blocks
2526 static noinline_for_stack
2527 int relocate_tree_blocks(struct btrfs_trans_handle *trans,
2528 struct reloc_control *rc, struct rb_root *blocks)
2530 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
2531 struct btrfs_backref_node *node;
2532 struct btrfs_path *path;
2533 struct tree_block *block;
2534 struct tree_block *next;
2538 path = btrfs_alloc_path();
2541 goto out_free_blocks;
2544 /* Kick in readahead for tree blocks with missing keys */
2545 rbtree_postorder_for_each_entry_safe(block, next, blocks, rb_node) {
2546 if (!block->key_ready)
2547 readahead_tree_block(fs_info, block->bytenr);
2550 /* Get first keys */
2551 rbtree_postorder_for_each_entry_safe(block, next, blocks, rb_node) {
2552 if (!block->key_ready) {
2553 err = get_tree_block_key(fs_info, block);
2559 /* Do tree relocation */
2560 rbtree_postorder_for_each_entry_safe(block, next, blocks, rb_node) {
2561 node = build_backref_tree(rc, &block->key,
2562 block->level, block->bytenr);
2564 err = PTR_ERR(node);
2568 ret = relocate_tree_block(trans, rc, node, &block->key,
2576 err = finish_pending_nodes(trans, rc, path, err);
2579 btrfs_free_path(path);
2581 free_block_list(blocks);
2585 static noinline_for_stack int prealloc_file_extent_cluster(
2586 struct btrfs_inode *inode,
2587 struct file_extent_cluster *cluster)
2592 u64 offset = inode->index_cnt;
2596 u64 prealloc_start = cluster->start - offset;
2597 u64 prealloc_end = cluster->end - offset;
2598 u64 cur_offset = prealloc_start;
2600 BUG_ON(cluster->start != cluster->boundary[0]);
2601 ret = btrfs_alloc_data_chunk_ondemand(inode,
2602 prealloc_end + 1 - prealloc_start);
2606 inode_lock(&inode->vfs_inode);
2607 for (nr = 0; nr < cluster->nr; nr++) {
2608 start = cluster->boundary[nr] - offset;
2609 if (nr + 1 < cluster->nr)
2610 end = cluster->boundary[nr + 1] - 1 - offset;
2612 end = cluster->end - offset;
2614 lock_extent(&inode->io_tree, start, end);
2615 num_bytes = end + 1 - start;
2616 ret = btrfs_prealloc_file_range(&inode->vfs_inode, 0, start,
2617 num_bytes, num_bytes,
2618 end + 1, &alloc_hint);
2619 cur_offset = end + 1;
2620 unlock_extent(&inode->io_tree, start, end);
2624 inode_unlock(&inode->vfs_inode);
2626 if (cur_offset < prealloc_end)
2627 btrfs_free_reserved_data_space_noquota(inode->root->fs_info,
2628 prealloc_end + 1 - cur_offset);
2632 static noinline_for_stack
2633 int setup_extent_mapping(struct inode *inode, u64 start, u64 end,
2636 struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
2637 struct extent_map *em;
2640 em = alloc_extent_map();
2645 em->len = end + 1 - start;
2646 em->block_len = em->len;
2647 em->block_start = block_start;
2648 set_bit(EXTENT_FLAG_PINNED, &em->flags);
2650 lock_extent(&BTRFS_I(inode)->io_tree, start, end);
2652 write_lock(&em_tree->lock);
2653 ret = add_extent_mapping(em_tree, em, 0);
2654 write_unlock(&em_tree->lock);
2655 if (ret != -EEXIST) {
2656 free_extent_map(em);
2659 btrfs_drop_extent_cache(BTRFS_I(inode), start, end, 0);
2661 unlock_extent(&BTRFS_I(inode)->io_tree, start, end);
2666 * Allow error injection to test balance cancellation
2668 int btrfs_should_cancel_balance(struct btrfs_fs_info *fs_info)
2670 return atomic_read(&fs_info->balance_cancel_req) ||
2671 fatal_signal_pending(current);
2673 ALLOW_ERROR_INJECTION(btrfs_should_cancel_balance, TRUE);
2675 static int relocate_file_extent_cluster(struct inode *inode,
2676 struct file_extent_cluster *cluster)
2678 struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
2681 u64 offset = BTRFS_I(inode)->index_cnt;
2682 unsigned long index;
2683 unsigned long last_index;
2685 struct file_ra_state *ra;
2686 gfp_t mask = btrfs_alloc_write_mask(inode->i_mapping);
2693 ra = kzalloc(sizeof(*ra), GFP_NOFS);
2697 ret = prealloc_file_extent_cluster(BTRFS_I(inode), cluster);
2701 file_ra_state_init(ra, inode->i_mapping);
2703 ret = setup_extent_mapping(inode, cluster->start - offset,
2704 cluster->end - offset, cluster->start);
2708 index = (cluster->start - offset) >> PAGE_SHIFT;
2709 last_index = (cluster->end - offset) >> PAGE_SHIFT;
2710 while (index <= last_index) {
2711 ret = btrfs_delalloc_reserve_metadata(BTRFS_I(inode),
2716 page = find_lock_page(inode->i_mapping, index);
2718 page_cache_sync_readahead(inode->i_mapping,
2720 last_index + 1 - index);
2721 page = find_or_create_page(inode->i_mapping, index,
2724 btrfs_delalloc_release_metadata(BTRFS_I(inode),
2726 btrfs_delalloc_release_extents(BTRFS_I(inode),
2733 if (PageReadahead(page)) {
2734 page_cache_async_readahead(inode->i_mapping,
2735 ra, NULL, page, index,
2736 last_index + 1 - index);
2739 if (!PageUptodate(page)) {
2740 btrfs_readpage(NULL, page);
2742 if (!PageUptodate(page)) {
2745 btrfs_delalloc_release_metadata(BTRFS_I(inode),
2747 btrfs_delalloc_release_extents(BTRFS_I(inode),
2754 page_start = page_offset(page);
2755 page_end = page_start + PAGE_SIZE - 1;
2757 lock_extent(&BTRFS_I(inode)->io_tree, page_start, page_end);
2759 set_page_extent_mapped(page);
2761 if (nr < cluster->nr &&
2762 page_start + offset == cluster->boundary[nr]) {
2763 set_extent_bits(&BTRFS_I(inode)->io_tree,
2764 page_start, page_end,
2769 ret = btrfs_set_extent_delalloc(BTRFS_I(inode), page_start,
2774 btrfs_delalloc_release_metadata(BTRFS_I(inode),
2776 btrfs_delalloc_release_extents(BTRFS_I(inode),
2779 clear_extent_bits(&BTRFS_I(inode)->io_tree,
2780 page_start, page_end,
2781 EXTENT_LOCKED | EXTENT_BOUNDARY);
2785 set_page_dirty(page);
2787 unlock_extent(&BTRFS_I(inode)->io_tree,
2788 page_start, page_end);
2793 btrfs_delalloc_release_extents(BTRFS_I(inode), PAGE_SIZE);
2794 balance_dirty_pages_ratelimited(inode->i_mapping);
2795 btrfs_throttle(fs_info);
2796 if (btrfs_should_cancel_balance(fs_info)) {
2801 WARN_ON(nr != cluster->nr);
2807 static noinline_for_stack
2808 int relocate_data_extent(struct inode *inode, struct btrfs_key *extent_key,
2809 struct file_extent_cluster *cluster)
2813 if (cluster->nr > 0 && extent_key->objectid != cluster->end + 1) {
2814 ret = relocate_file_extent_cluster(inode, cluster);
2821 cluster->start = extent_key->objectid;
2823 BUG_ON(cluster->nr >= MAX_EXTENTS);
2824 cluster->end = extent_key->objectid + extent_key->offset - 1;
2825 cluster->boundary[cluster->nr] = extent_key->objectid;
2828 if (cluster->nr >= MAX_EXTENTS) {
2829 ret = relocate_file_extent_cluster(inode, cluster);
2838 * helper to add a tree block to the list.
2839 * the major work is getting the generation and level of the block
2841 static int add_tree_block(struct reloc_control *rc,
2842 struct btrfs_key *extent_key,
2843 struct btrfs_path *path,
2844 struct rb_root *blocks)
2846 struct extent_buffer *eb;
2847 struct btrfs_extent_item *ei;
2848 struct btrfs_tree_block_info *bi;
2849 struct tree_block *block;
2850 struct rb_node *rb_node;
2855 eb = path->nodes[0];
2856 item_size = btrfs_item_size_nr(eb, path->slots[0]);
2858 if (extent_key->type == BTRFS_METADATA_ITEM_KEY ||
2859 item_size >= sizeof(*ei) + sizeof(*bi)) {
2860 ei = btrfs_item_ptr(eb, path->slots[0],
2861 struct btrfs_extent_item);
2862 if (extent_key->type == BTRFS_EXTENT_ITEM_KEY) {
2863 bi = (struct btrfs_tree_block_info *)(ei + 1);
2864 level = btrfs_tree_block_level(eb, bi);
2866 level = (int)extent_key->offset;
2868 generation = btrfs_extent_generation(eb, ei);
2869 } else if (unlikely(item_size == sizeof(struct btrfs_extent_item_v0))) {
2870 btrfs_print_v0_err(eb->fs_info);
2871 btrfs_handle_fs_error(eb->fs_info, -EINVAL, NULL);
2877 btrfs_release_path(path);
2879 BUG_ON(level == -1);
2881 block = kmalloc(sizeof(*block), GFP_NOFS);
2885 block->bytenr = extent_key->objectid;
2886 block->key.objectid = rc->extent_root->fs_info->nodesize;
2887 block->key.offset = generation;
2888 block->level = level;
2889 block->key_ready = 0;
2891 rb_node = rb_simple_insert(blocks, block->bytenr, &block->rb_node);
2893 btrfs_backref_panic(rc->extent_root->fs_info, block->bytenr,
2900 * helper to add tree blocks for backref of type BTRFS_SHARED_DATA_REF_KEY
2902 static int __add_tree_block(struct reloc_control *rc,
2903 u64 bytenr, u32 blocksize,
2904 struct rb_root *blocks)
2906 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
2907 struct btrfs_path *path;
2908 struct btrfs_key key;
2910 bool skinny = btrfs_fs_incompat(fs_info, SKINNY_METADATA);
2912 if (tree_block_processed(bytenr, rc))
2915 if (rb_simple_search(blocks, bytenr))
2918 path = btrfs_alloc_path();
2922 key.objectid = bytenr;
2924 key.type = BTRFS_METADATA_ITEM_KEY;
2925 key.offset = (u64)-1;
2927 key.type = BTRFS_EXTENT_ITEM_KEY;
2928 key.offset = blocksize;
2931 path->search_commit_root = 1;
2932 path->skip_locking = 1;
2933 ret = btrfs_search_slot(NULL, rc->extent_root, &key, path, 0, 0);
2937 if (ret > 0 && skinny) {
2938 if (path->slots[0]) {
2940 btrfs_item_key_to_cpu(path->nodes[0], &key,
2942 if (key.objectid == bytenr &&
2943 (key.type == BTRFS_METADATA_ITEM_KEY ||
2944 (key.type == BTRFS_EXTENT_ITEM_KEY &&
2945 key.offset == blocksize)))
2951 btrfs_release_path(path);
2957 btrfs_print_leaf(path->nodes[0]);
2959 "tree block extent item (%llu) is not found in extent tree",
2966 ret = add_tree_block(rc, &key, path, blocks);
2968 btrfs_free_path(path);
2972 static int delete_block_group_cache(struct btrfs_fs_info *fs_info,
2973 struct btrfs_block_group *block_group,
2974 struct inode *inode,
2977 struct btrfs_root *root = fs_info->tree_root;
2978 struct btrfs_trans_handle *trans;
2984 inode = btrfs_iget(fs_info->sb, ino, root);
2989 ret = btrfs_check_trunc_cache_free_space(fs_info,
2990 &fs_info->global_block_rsv);
2994 trans = btrfs_join_transaction(root);
2995 if (IS_ERR(trans)) {
2996 ret = PTR_ERR(trans);
3000 ret = btrfs_truncate_free_space_cache(trans, block_group, inode);
3002 btrfs_end_transaction(trans);
3003 btrfs_btree_balance_dirty(fs_info);
3010 * Locate the free space cache EXTENT_DATA in root tree leaf and delete the
3011 * cache inode, to avoid free space cache data extent blocking data relocation.
3013 static int delete_v1_space_cache(struct extent_buffer *leaf,
3014 struct btrfs_block_group *block_group,
3017 u64 space_cache_ino;
3018 struct btrfs_file_extent_item *ei;
3019 struct btrfs_key key;
3024 if (btrfs_header_owner(leaf) != BTRFS_ROOT_TREE_OBJECTID)
3027 for (i = 0; i < btrfs_header_nritems(leaf); i++) {
3028 btrfs_item_key_to_cpu(leaf, &key, i);
3029 if (key.type != BTRFS_EXTENT_DATA_KEY)
3031 ei = btrfs_item_ptr(leaf, i, struct btrfs_file_extent_item);
3032 if (btrfs_file_extent_type(leaf, ei) == BTRFS_FILE_EXTENT_REG &&
3033 btrfs_file_extent_disk_bytenr(leaf, ei) == data_bytenr) {
3035 space_cache_ino = key.objectid;
3041 ret = delete_block_group_cache(leaf->fs_info, block_group, NULL,
3047 * helper to find all tree blocks that reference a given data extent
3049 static noinline_for_stack
3050 int add_data_references(struct reloc_control *rc,
3051 struct btrfs_key *extent_key,
3052 struct btrfs_path *path,
3053 struct rb_root *blocks)
3055 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
3056 struct ulist *leaves = NULL;
3057 struct ulist_iterator leaf_uiter;
3058 struct ulist_node *ref_node = NULL;
3059 const u32 blocksize = fs_info->nodesize;
3062 btrfs_release_path(path);
3063 ret = btrfs_find_all_leafs(NULL, fs_info, extent_key->objectid,
3064 0, &leaves, NULL, true);
3068 ULIST_ITER_INIT(&leaf_uiter);
3069 while ((ref_node = ulist_next(leaves, &leaf_uiter))) {
3070 struct extent_buffer *eb;
3072 eb = read_tree_block(fs_info, ref_node->val, 0, 0, NULL);
3077 ret = delete_v1_space_cache(eb, rc->block_group,
3078 extent_key->objectid);
3079 free_extent_buffer(eb);
3082 ret = __add_tree_block(rc, ref_node->val, blocksize, blocks);
3087 free_block_list(blocks);
3093 * helper to find next unprocessed extent
3095 static noinline_for_stack
3096 int find_next_extent(struct reloc_control *rc, struct btrfs_path *path,
3097 struct btrfs_key *extent_key)
3099 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
3100 struct btrfs_key key;
3101 struct extent_buffer *leaf;
3102 u64 start, end, last;
3105 last = rc->block_group->start + rc->block_group->length;
3108 if (rc->search_start >= last) {
3113 key.objectid = rc->search_start;
3114 key.type = BTRFS_EXTENT_ITEM_KEY;
3117 path->search_commit_root = 1;
3118 path->skip_locking = 1;
3119 ret = btrfs_search_slot(NULL, rc->extent_root, &key, path,
3124 leaf = path->nodes[0];
3125 if (path->slots[0] >= btrfs_header_nritems(leaf)) {
3126 ret = btrfs_next_leaf(rc->extent_root, path);
3129 leaf = path->nodes[0];
3132 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
3133 if (key.objectid >= last) {
3138 if (key.type != BTRFS_EXTENT_ITEM_KEY &&
3139 key.type != BTRFS_METADATA_ITEM_KEY) {
3144 if (key.type == BTRFS_EXTENT_ITEM_KEY &&
3145 key.objectid + key.offset <= rc->search_start) {
3150 if (key.type == BTRFS_METADATA_ITEM_KEY &&
3151 key.objectid + fs_info->nodesize <=
3157 ret = find_first_extent_bit(&rc->processed_blocks,
3158 key.objectid, &start, &end,
3159 EXTENT_DIRTY, NULL);
3161 if (ret == 0 && start <= key.objectid) {
3162 btrfs_release_path(path);
3163 rc->search_start = end + 1;
3165 if (key.type == BTRFS_EXTENT_ITEM_KEY)
3166 rc->search_start = key.objectid + key.offset;
3168 rc->search_start = key.objectid +
3170 memcpy(extent_key, &key, sizeof(key));
3174 btrfs_release_path(path);
3178 static void set_reloc_control(struct reloc_control *rc)
3180 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
3182 mutex_lock(&fs_info->reloc_mutex);
3183 fs_info->reloc_ctl = rc;
3184 mutex_unlock(&fs_info->reloc_mutex);
3187 static void unset_reloc_control(struct reloc_control *rc)
3189 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
3191 mutex_lock(&fs_info->reloc_mutex);
3192 fs_info->reloc_ctl = NULL;
3193 mutex_unlock(&fs_info->reloc_mutex);
3196 static int check_extent_flags(u64 flags)
3198 if ((flags & BTRFS_EXTENT_FLAG_DATA) &&
3199 (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK))
3201 if (!(flags & BTRFS_EXTENT_FLAG_DATA) &&
3202 !(flags & BTRFS_EXTENT_FLAG_TREE_BLOCK))
3204 if ((flags & BTRFS_EXTENT_FLAG_DATA) &&
3205 (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF))
3210 static noinline_for_stack
3211 int prepare_to_relocate(struct reloc_control *rc)
3213 struct btrfs_trans_handle *trans;
3216 rc->block_rsv = btrfs_alloc_block_rsv(rc->extent_root->fs_info,
3217 BTRFS_BLOCK_RSV_TEMP);
3221 memset(&rc->cluster, 0, sizeof(rc->cluster));
3222 rc->search_start = rc->block_group->start;
3223 rc->extents_found = 0;
3224 rc->nodes_relocated = 0;
3225 rc->merging_rsv_size = 0;
3226 rc->reserved_bytes = 0;
3227 rc->block_rsv->size = rc->extent_root->fs_info->nodesize *
3228 RELOCATION_RESERVED_NODES;
3229 ret = btrfs_block_rsv_refill(rc->extent_root,
3230 rc->block_rsv, rc->block_rsv->size,
3231 BTRFS_RESERVE_FLUSH_ALL);
3235 rc->create_reloc_tree = 1;
3236 set_reloc_control(rc);
3238 trans = btrfs_join_transaction(rc->extent_root);
3239 if (IS_ERR(trans)) {
3240 unset_reloc_control(rc);
3242 * extent tree is not a ref_cow tree and has no reloc_root to
3243 * cleanup. And callers are responsible to free the above
3246 return PTR_ERR(trans);
3248 btrfs_commit_transaction(trans);
3252 static noinline_for_stack int relocate_block_group(struct reloc_control *rc)
3254 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
3255 struct rb_root blocks = RB_ROOT;
3256 struct btrfs_key key;
3257 struct btrfs_trans_handle *trans = NULL;
3258 struct btrfs_path *path;
3259 struct btrfs_extent_item *ei;
3266 path = btrfs_alloc_path();
3269 path->reada = READA_FORWARD;
3271 ret = prepare_to_relocate(rc);
3278 rc->reserved_bytes = 0;
3279 ret = btrfs_block_rsv_refill(rc->extent_root,
3280 rc->block_rsv, rc->block_rsv->size,
3281 BTRFS_RESERVE_FLUSH_ALL);
3287 trans = btrfs_start_transaction(rc->extent_root, 0);
3288 if (IS_ERR(trans)) {
3289 err = PTR_ERR(trans);
3294 if (update_backref_cache(trans, &rc->backref_cache)) {
3295 btrfs_end_transaction(trans);
3300 ret = find_next_extent(rc, path, &key);
3306 rc->extents_found++;
3308 ei = btrfs_item_ptr(path->nodes[0], path->slots[0],
3309 struct btrfs_extent_item);
3310 item_size = btrfs_item_size_nr(path->nodes[0], path->slots[0]);
3311 if (item_size >= sizeof(*ei)) {
3312 flags = btrfs_extent_flags(path->nodes[0], ei);
3313 ret = check_extent_flags(flags);
3315 } else if (unlikely(item_size == sizeof(struct btrfs_extent_item_v0))) {
3317 btrfs_print_v0_err(trans->fs_info);
3318 btrfs_abort_transaction(trans, err);
3324 if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) {
3325 ret = add_tree_block(rc, &key, path, &blocks);
3326 } else if (rc->stage == UPDATE_DATA_PTRS &&
3327 (flags & BTRFS_EXTENT_FLAG_DATA)) {
3328 ret = add_data_references(rc, &key, path, &blocks);
3330 btrfs_release_path(path);
3338 if (!RB_EMPTY_ROOT(&blocks)) {
3339 ret = relocate_tree_blocks(trans, rc, &blocks);
3341 if (ret != -EAGAIN) {
3345 rc->extents_found--;
3346 rc->search_start = key.objectid;
3350 btrfs_end_transaction_throttle(trans);
3351 btrfs_btree_balance_dirty(fs_info);
3354 if (rc->stage == MOVE_DATA_EXTENTS &&
3355 (flags & BTRFS_EXTENT_FLAG_DATA)) {
3356 rc->found_file_extent = 1;
3357 ret = relocate_data_extent(rc->data_inode,
3358 &key, &rc->cluster);
3364 if (btrfs_should_cancel_balance(fs_info)) {
3369 if (trans && progress && err == -ENOSPC) {
3370 ret = btrfs_force_chunk_alloc(trans, rc->block_group->flags);
3378 btrfs_release_path(path);
3379 clear_extent_bits(&rc->processed_blocks, 0, (u64)-1, EXTENT_DIRTY);
3382 btrfs_end_transaction_throttle(trans);
3383 btrfs_btree_balance_dirty(fs_info);
3387 ret = relocate_file_extent_cluster(rc->data_inode,
3393 rc->create_reloc_tree = 0;
3394 set_reloc_control(rc);
3396 btrfs_backref_release_cache(&rc->backref_cache);
3397 btrfs_block_rsv_release(fs_info, rc->block_rsv, (u64)-1, NULL);
3400 * Even in the case when the relocation is cancelled, we should all go
3401 * through prepare_to_merge() and merge_reloc_roots().
3403 * For error (including cancelled balance), prepare_to_merge() will
3404 * mark all reloc trees orphan, then queue them for cleanup in
3405 * merge_reloc_roots()
3407 err = prepare_to_merge(rc, err);
3409 merge_reloc_roots(rc);
3411 rc->merge_reloc_tree = 0;
3412 unset_reloc_control(rc);
3413 btrfs_block_rsv_release(fs_info, rc->block_rsv, (u64)-1, NULL);
3415 /* get rid of pinned extents */
3416 trans = btrfs_join_transaction(rc->extent_root);
3417 if (IS_ERR(trans)) {
3418 err = PTR_ERR(trans);
3421 btrfs_commit_transaction(trans);
3423 ret = clean_dirty_subvols(rc);
3424 if (ret < 0 && !err)
3426 btrfs_free_block_rsv(fs_info, rc->block_rsv);
3427 btrfs_free_path(path);
3431 static int __insert_orphan_inode(struct btrfs_trans_handle *trans,
3432 struct btrfs_root *root, u64 objectid)
3434 struct btrfs_path *path;
3435 struct btrfs_inode_item *item;
3436 struct extent_buffer *leaf;
3439 path = btrfs_alloc_path();
3443 ret = btrfs_insert_empty_inode(trans, root, path, objectid);
3447 leaf = path->nodes[0];
3448 item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_inode_item);
3449 memzero_extent_buffer(leaf, (unsigned long)item, sizeof(*item));
3450 btrfs_set_inode_generation(leaf, item, 1);
3451 btrfs_set_inode_size(leaf, item, 0);
3452 btrfs_set_inode_mode(leaf, item, S_IFREG | 0600);
3453 btrfs_set_inode_flags(leaf, item, BTRFS_INODE_NOCOMPRESS |
3454 BTRFS_INODE_PREALLOC);
3455 btrfs_mark_buffer_dirty(leaf);
3457 btrfs_free_path(path);
3462 * helper to create inode for data relocation.
3463 * the inode is in data relocation tree and its link count is 0
3465 static noinline_for_stack
3466 struct inode *create_reloc_inode(struct btrfs_fs_info *fs_info,
3467 struct btrfs_block_group *group)
3469 struct inode *inode = NULL;
3470 struct btrfs_trans_handle *trans;
3471 struct btrfs_root *root;
3475 root = btrfs_grab_root(fs_info->data_reloc_root);
3476 trans = btrfs_start_transaction(root, 6);
3477 if (IS_ERR(trans)) {
3478 btrfs_put_root(root);
3479 return ERR_CAST(trans);
3482 err = btrfs_find_free_objectid(root, &objectid);
3486 err = __insert_orphan_inode(trans, root, objectid);
3489 inode = btrfs_iget(fs_info->sb, objectid, root);
3490 BUG_ON(IS_ERR(inode));
3491 BTRFS_I(inode)->index_cnt = group->start;
3493 err = btrfs_orphan_add(trans, BTRFS_I(inode));
3495 btrfs_put_root(root);
3496 btrfs_end_transaction(trans);
3497 btrfs_btree_balance_dirty(fs_info);
3501 inode = ERR_PTR(err);
3506 static struct reloc_control *alloc_reloc_control(struct btrfs_fs_info *fs_info)
3508 struct reloc_control *rc;
3510 rc = kzalloc(sizeof(*rc), GFP_NOFS);
3514 INIT_LIST_HEAD(&rc->reloc_roots);
3515 INIT_LIST_HEAD(&rc->dirty_subvol_roots);
3516 btrfs_backref_init_cache(fs_info, &rc->backref_cache, 1);
3517 mapping_tree_init(&rc->reloc_root_tree);
3518 extent_io_tree_init(fs_info, &rc->processed_blocks,
3519 IO_TREE_RELOC_BLOCKS, NULL);
3523 static void free_reloc_control(struct reloc_control *rc)
3525 struct mapping_node *node, *tmp;
3527 free_reloc_roots(&rc->reloc_roots);
3528 rbtree_postorder_for_each_entry_safe(node, tmp,
3529 &rc->reloc_root_tree.rb_root, rb_node)
3536 * Print the block group being relocated
3538 static void describe_relocation(struct btrfs_fs_info *fs_info,
3539 struct btrfs_block_group *block_group)
3541 char buf[128] = {'\0'};
3543 btrfs_describe_block_groups(block_group->flags, buf, sizeof(buf));
3546 "relocating block group %llu flags %s",
3547 block_group->start, buf);
3550 static const char *stage_to_string(int stage)
3552 if (stage == MOVE_DATA_EXTENTS)
3553 return "move data extents";
3554 if (stage == UPDATE_DATA_PTRS)
3555 return "update data pointers";
3560 * function to relocate all extents in a block group.
3562 int btrfs_relocate_block_group(struct btrfs_fs_info *fs_info, u64 group_start)
3564 struct btrfs_block_group *bg;
3565 struct btrfs_root *extent_root = fs_info->extent_root;
3566 struct reloc_control *rc;
3567 struct inode *inode;
3568 struct btrfs_path *path;
3573 bg = btrfs_lookup_block_group(fs_info, group_start);
3577 if (btrfs_pinned_by_swapfile(fs_info, bg)) {
3578 btrfs_put_block_group(bg);
3582 rc = alloc_reloc_control(fs_info);
3584 btrfs_put_block_group(bg);
3588 rc->extent_root = extent_root;
3589 rc->block_group = bg;
3591 ret = btrfs_inc_block_group_ro(rc->block_group, true);
3598 path = btrfs_alloc_path();
3604 inode = lookup_free_space_inode(rc->block_group, path);
3605 btrfs_free_path(path);
3608 ret = delete_block_group_cache(fs_info, rc->block_group, inode, 0);
3610 ret = PTR_ERR(inode);
3612 if (ret && ret != -ENOENT) {
3617 rc->data_inode = create_reloc_inode(fs_info, rc->block_group);
3618 if (IS_ERR(rc->data_inode)) {
3619 err = PTR_ERR(rc->data_inode);
3620 rc->data_inode = NULL;
3624 describe_relocation(fs_info, rc->block_group);
3626 btrfs_wait_block_group_reservations(rc->block_group);
3627 btrfs_wait_nocow_writers(rc->block_group);
3628 btrfs_wait_ordered_roots(fs_info, U64_MAX,
3629 rc->block_group->start,
3630 rc->block_group->length);
3635 mutex_lock(&fs_info->cleaner_mutex);
3636 ret = relocate_block_group(rc);
3637 mutex_unlock(&fs_info->cleaner_mutex);
3641 finishes_stage = rc->stage;
3643 * We may have gotten ENOSPC after we already dirtied some
3644 * extents. If writeout happens while we're relocating a
3645 * different block group we could end up hitting the
3646 * BUG_ON(rc->stage == UPDATE_DATA_PTRS) in
3647 * btrfs_reloc_cow_block. Make sure we write everything out
3648 * properly so we don't trip over this problem, and then break
3649 * out of the loop if we hit an error.
3651 if (rc->stage == MOVE_DATA_EXTENTS && rc->found_file_extent) {
3652 ret = btrfs_wait_ordered_range(rc->data_inode, 0,
3656 invalidate_mapping_pages(rc->data_inode->i_mapping,
3658 rc->stage = UPDATE_DATA_PTRS;
3664 if (rc->extents_found == 0)
3667 btrfs_info(fs_info, "found %llu extents, stage: %s",
3668 rc->extents_found, stage_to_string(finishes_stage));
3671 WARN_ON(rc->block_group->pinned > 0);
3672 WARN_ON(rc->block_group->reserved > 0);
3673 WARN_ON(rc->block_group->used > 0);
3676 btrfs_dec_block_group_ro(rc->block_group);
3677 iput(rc->data_inode);
3678 btrfs_put_block_group(rc->block_group);
3679 free_reloc_control(rc);
3683 static noinline_for_stack int mark_garbage_root(struct btrfs_root *root)
3685 struct btrfs_fs_info *fs_info = root->fs_info;
3686 struct btrfs_trans_handle *trans;
3689 trans = btrfs_start_transaction(fs_info->tree_root, 0);
3691 return PTR_ERR(trans);
3693 memset(&root->root_item.drop_progress, 0,
3694 sizeof(root->root_item.drop_progress));
3695 root->root_item.drop_level = 0;
3696 btrfs_set_root_refs(&root->root_item, 0);
3697 ret = btrfs_update_root(trans, fs_info->tree_root,
3698 &root->root_key, &root->root_item);
3700 err = btrfs_end_transaction(trans);
3707 * recover relocation interrupted by system crash.
3709 * this function resumes merging reloc trees with corresponding fs trees.
3710 * this is important for keeping the sharing of tree blocks
3712 int btrfs_recover_relocation(struct btrfs_root *root)
3714 struct btrfs_fs_info *fs_info = root->fs_info;
3715 LIST_HEAD(reloc_roots);
3716 struct btrfs_key key;
3717 struct btrfs_root *fs_root;
3718 struct btrfs_root *reloc_root;
3719 struct btrfs_path *path;
3720 struct extent_buffer *leaf;
3721 struct reloc_control *rc = NULL;
3722 struct btrfs_trans_handle *trans;
3726 path = btrfs_alloc_path();
3729 path->reada = READA_BACK;
3731 key.objectid = BTRFS_TREE_RELOC_OBJECTID;
3732 key.type = BTRFS_ROOT_ITEM_KEY;
3733 key.offset = (u64)-1;
3736 ret = btrfs_search_slot(NULL, fs_info->tree_root, &key,
3743 if (path->slots[0] == 0)
3747 leaf = path->nodes[0];
3748 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
3749 btrfs_release_path(path);
3751 if (key.objectid != BTRFS_TREE_RELOC_OBJECTID ||
3752 key.type != BTRFS_ROOT_ITEM_KEY)
3755 reloc_root = btrfs_read_tree_root(root, &key);
3756 if (IS_ERR(reloc_root)) {
3757 err = PTR_ERR(reloc_root);
3761 set_bit(BTRFS_ROOT_SHAREABLE, &reloc_root->state);
3762 list_add(&reloc_root->root_list, &reloc_roots);
3764 if (btrfs_root_refs(&reloc_root->root_item) > 0) {
3765 fs_root = btrfs_get_fs_root(fs_info,
3766 reloc_root->root_key.offset, false);
3767 if (IS_ERR(fs_root)) {
3768 ret = PTR_ERR(fs_root);
3769 if (ret != -ENOENT) {
3773 ret = mark_garbage_root(reloc_root);
3779 btrfs_put_root(fs_root);
3783 if (key.offset == 0)
3788 btrfs_release_path(path);
3790 if (list_empty(&reloc_roots))
3793 rc = alloc_reloc_control(fs_info);
3799 rc->extent_root = fs_info->extent_root;
3801 set_reloc_control(rc);
3803 trans = btrfs_join_transaction(rc->extent_root);
3804 if (IS_ERR(trans)) {
3805 err = PTR_ERR(trans);
3809 rc->merge_reloc_tree = 1;
3811 while (!list_empty(&reloc_roots)) {
3812 reloc_root = list_entry(reloc_roots.next,
3813 struct btrfs_root, root_list);
3814 list_del(&reloc_root->root_list);
3816 if (btrfs_root_refs(&reloc_root->root_item) == 0) {
3817 list_add_tail(&reloc_root->root_list,
3822 fs_root = btrfs_get_fs_root(fs_info, reloc_root->root_key.offset,
3824 if (IS_ERR(fs_root)) {
3825 err = PTR_ERR(fs_root);
3826 list_add_tail(&reloc_root->root_list, &reloc_roots);
3827 btrfs_end_transaction(trans);
3831 err = __add_reloc_root(reloc_root);
3832 BUG_ON(err < 0); /* -ENOMEM or logic error */
3833 fs_root->reloc_root = btrfs_grab_root(reloc_root);
3834 btrfs_put_root(fs_root);
3837 err = btrfs_commit_transaction(trans);
3841 merge_reloc_roots(rc);
3843 unset_reloc_control(rc);
3845 trans = btrfs_join_transaction(rc->extent_root);
3846 if (IS_ERR(trans)) {
3847 err = PTR_ERR(trans);
3850 err = btrfs_commit_transaction(trans);
3852 ret = clean_dirty_subvols(rc);
3853 if (ret < 0 && !err)
3856 unset_reloc_control(rc);
3857 free_reloc_control(rc);
3859 free_reloc_roots(&reloc_roots);
3861 btrfs_free_path(path);
3864 /* cleanup orphan inode in data relocation tree */
3865 fs_root = btrfs_grab_root(fs_info->data_reloc_root);
3867 err = btrfs_orphan_cleanup(fs_root);
3868 btrfs_put_root(fs_root);
3874 * helper to add ordered checksum for data relocation.
3876 * cloning checksum properly handles the nodatasum extents.
3877 * it also saves CPU time to re-calculate the checksum.
3879 int btrfs_reloc_clone_csums(struct btrfs_inode *inode, u64 file_pos, u64 len)
3881 struct btrfs_fs_info *fs_info = inode->root->fs_info;
3882 struct btrfs_ordered_sum *sums;
3883 struct btrfs_ordered_extent *ordered;
3889 ordered = btrfs_lookup_ordered_extent(inode, file_pos);
3890 BUG_ON(ordered->file_offset != file_pos || ordered->num_bytes != len);
3892 disk_bytenr = file_pos + inode->index_cnt;
3893 ret = btrfs_lookup_csums_range(fs_info->csum_root, disk_bytenr,
3894 disk_bytenr + len - 1, &list, 0);
3898 while (!list_empty(&list)) {
3899 sums = list_entry(list.next, struct btrfs_ordered_sum, list);
3900 list_del_init(&sums->list);
3903 * We need to offset the new_bytenr based on where the csum is.
3904 * We need to do this because we will read in entire prealloc
3905 * extents but we may have written to say the middle of the
3906 * prealloc extent, so we need to make sure the csum goes with
3907 * the right disk offset.
3909 * We can do this because the data reloc inode refers strictly
3910 * to the on disk bytes, so we don't have to worry about
3911 * disk_len vs real len like with real inodes since it's all
3914 new_bytenr = ordered->disk_bytenr + sums->bytenr - disk_bytenr;
3915 sums->bytenr = new_bytenr;
3917 btrfs_add_ordered_sum(ordered, sums);
3920 btrfs_put_ordered_extent(ordered);
3924 int btrfs_reloc_cow_block(struct btrfs_trans_handle *trans,
3925 struct btrfs_root *root, struct extent_buffer *buf,
3926 struct extent_buffer *cow)
3928 struct btrfs_fs_info *fs_info = root->fs_info;
3929 struct reloc_control *rc;
3930 struct btrfs_backref_node *node;
3935 rc = fs_info->reloc_ctl;
3939 BUG_ON(rc->stage == UPDATE_DATA_PTRS &&
3940 root->root_key.objectid == BTRFS_DATA_RELOC_TREE_OBJECTID);
3942 level = btrfs_header_level(buf);
3943 if (btrfs_header_generation(buf) <=
3944 btrfs_root_last_snapshot(&root->root_item))
3947 if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID &&
3948 rc->create_reloc_tree) {
3949 WARN_ON(!first_cow && level == 0);
3951 node = rc->backref_cache.path[level];
3952 BUG_ON(node->bytenr != buf->start &&
3953 node->new_bytenr != buf->start);
3955 btrfs_backref_drop_node_buffer(node);
3956 atomic_inc(&cow->refs);
3958 node->new_bytenr = cow->start;
3960 if (!node->pending) {
3961 list_move_tail(&node->list,
3962 &rc->backref_cache.pending[level]);
3967 mark_block_processed(rc, node);
3969 if (first_cow && level > 0)
3970 rc->nodes_relocated += buf->len;
3973 if (level == 0 && first_cow && rc->stage == UPDATE_DATA_PTRS)
3974 ret = replace_file_extents(trans, rc, root, cow);
3979 * called before creating snapshot. it calculates metadata reservation
3980 * required for relocating tree blocks in the snapshot
3982 void btrfs_reloc_pre_snapshot(struct btrfs_pending_snapshot *pending,
3983 u64 *bytes_to_reserve)
3985 struct btrfs_root *root = pending->root;
3986 struct reloc_control *rc = root->fs_info->reloc_ctl;
3988 if (!rc || !have_reloc_root(root))
3991 if (!rc->merge_reloc_tree)
3994 root = root->reloc_root;
3995 BUG_ON(btrfs_root_refs(&root->root_item) == 0);
3997 * relocation is in the stage of merging trees. the space
3998 * used by merging a reloc tree is twice the size of
3999 * relocated tree nodes in the worst case. half for cowing
4000 * the reloc tree, half for cowing the fs tree. the space
4001 * used by cowing the reloc tree will be freed after the
4002 * tree is dropped. if we create snapshot, cowing the fs
4003 * tree may use more space than it frees. so we need
4004 * reserve extra space.
4006 *bytes_to_reserve += rc->nodes_relocated;
4010 * called after snapshot is created. migrate block reservation
4011 * and create reloc root for the newly created snapshot
4013 * This is similar to btrfs_init_reloc_root(), we come out of here with two
4014 * references held on the reloc_root, one for root->reloc_root and one for
4017 int btrfs_reloc_post_snapshot(struct btrfs_trans_handle *trans,
4018 struct btrfs_pending_snapshot *pending)
4020 struct btrfs_root *root = pending->root;
4021 struct btrfs_root *reloc_root;
4022 struct btrfs_root *new_root;
4023 struct reloc_control *rc = root->fs_info->reloc_ctl;
4026 if (!rc || !have_reloc_root(root))
4029 rc = root->fs_info->reloc_ctl;
4030 rc->merging_rsv_size += rc->nodes_relocated;
4032 if (rc->merge_reloc_tree) {
4033 ret = btrfs_block_rsv_migrate(&pending->block_rsv,
4035 rc->nodes_relocated, true);
4040 new_root = pending->snap;
4041 reloc_root = create_reloc_root(trans, root->reloc_root,
4042 new_root->root_key.objectid);
4043 if (IS_ERR(reloc_root))
4044 return PTR_ERR(reloc_root);
4046 ret = __add_reloc_root(reloc_root);
4048 new_root->reloc_root = btrfs_grab_root(reloc_root);
4050 if (rc->create_reloc_tree)
4051 ret = clone_backref_node(trans, rc, root, reloc_root);