1 // SPDX-License-Identifier: GPL-2.0
3 * Copyright (C) 2007 Oracle. All rights reserved.
6 #include <linux/sched.h>
9 #include "print-tree.h"
10 #include "transaction.h"
14 * Defrag all the leaves in a given btree.
15 * Read all the leaves and try to get key order to
16 * better reflect disk order
19 int btrfs_defrag_leaves(struct btrfs_trans_handle *trans,
20 struct btrfs_root *root)
22 struct btrfs_path *path = NULL;
30 if (root->fs_info->extent_root == root) {
32 * there's recursion here right now in the tree locking,
33 * we can't defrag the extent root without deadlock
38 if (!test_bit(BTRFS_ROOT_SHAREABLE, &root->state))
41 path = btrfs_alloc_path();
45 level = btrfs_header_level(root->node);
50 if (root->defrag_progress.objectid == 0) {
51 struct extent_buffer *root_node;
54 root_node = btrfs_lock_root_node(root);
55 btrfs_set_lock_blocking_write(root_node);
56 nritems = btrfs_header_nritems(root_node);
57 root->defrag_max.objectid = 0;
58 /* from above we know this is not a leaf */
59 btrfs_node_key_to_cpu(root_node, &root->defrag_max,
61 btrfs_tree_unlock(root_node);
62 free_extent_buffer(root_node);
63 memset(&key, 0, sizeof(key));
65 memcpy(&key, &root->defrag_progress, sizeof(key));
70 ret = btrfs_search_forward(root, &key, path, BTRFS_OLDEST_GENERATION);
77 btrfs_release_path(path);
79 * We don't need a lock on a leaf. btrfs_realloc_node() will lock all
80 * leafs from path->nodes[1], so set lowest_level to 1 to avoid later
81 * a deadlock (attempting to write lock an already write locked leaf).
83 path->lowest_level = 1;
84 wret = btrfs_search_slot(trans, root, &key, path, 0, 1);
90 if (!path->nodes[1]) {
95 * The node at level 1 must always be locked when our path has
96 * keep_locks set and lowest_level is 1, regardless of the value of
99 BUG_ON(path->locks[1] == 0);
100 ret = btrfs_realloc_node(trans, root,
103 &root->defrag_progress);
105 WARN_ON(ret == -EAGAIN);
109 * Now that we reallocated the node we can find the next key. Note that
110 * btrfs_find_next_key() can release our path and do another search
111 * without COWing, this is because even with path->keep_locks = 1,
112 * btrfs_search_slot() / ctree.c:unlock_up() does not keeps a lock on a
113 * node when path->slots[node_level - 1] does not point to the last
114 * item or a slot beyond the last item (ctree.c:unlock_up()). Therefore
115 * we search for the next key after reallocating our node.
117 path->slots[1] = btrfs_header_nritems(path->nodes[1]);
118 next_key_ret = btrfs_find_next_key(root, path, &key, 1,
119 BTRFS_OLDEST_GENERATION);
120 if (next_key_ret == 0) {
121 memcpy(&root->defrag_progress, &key, sizeof(key));
125 btrfs_free_path(path);
126 if (ret == -EAGAIN) {
127 if (root->defrag_max.objectid > root->defrag_progress.objectid)
129 if (root->defrag_max.type > root->defrag_progress.type)
131 if (root->defrag_max.offset > root->defrag_progress.offset)
137 memset(&root->defrag_progress, 0,
138 sizeof(root->defrag_progress));