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c1d7c514 | 1 | // SPDX-License-Identifier: GPL-2.0 |
6702ed49 CM |
2 | /* |
3 | * Copyright (C) 2007 Oracle. All rights reserved. | |
6702ed49 CM |
4 | */ |
5 | ||
6 | #include <linux/sched.h> | |
7 | #include "ctree.h" | |
8 | #include "disk-io.h" | |
9 | #include "print-tree.h" | |
10 | #include "transaction.h" | |
e7a84565 | 11 | #include "locking.h" |
6702ed49 | 12 | |
de78b51a ES |
13 | /* |
14 | * Defrag all the leaves in a given btree. | |
15 | * Read all the leaves and try to get key order to | |
d352ac68 CM |
16 | * better reflect disk order |
17 | */ | |
d397712b | 18 | |
6702ed49 | 19 | int btrfs_defrag_leaves(struct btrfs_trans_handle *trans, |
de78b51a | 20 | struct btrfs_root *root) |
6702ed49 CM |
21 | { |
22 | struct btrfs_path *path = NULL; | |
e7a84565 | 23 | struct btrfs_key key; |
6702ed49 CM |
24 | int ret = 0; |
25 | int wret; | |
26 | int level; | |
e7a84565 | 27 | int next_key_ret = 0; |
e9d0b13b | 28 | u64 last_ret = 0; |
3f157a2f | 29 | |
e7a84565 | 30 | if (root->fs_info->extent_root == root) { |
1b1e2135 CM |
31 | /* |
32 | * there's recursion here right now in the tree locking, | |
33 | * we can't defrag the extent root without deadlock | |
34 | */ | |
35 | goto out; | |
e7a84565 | 36 | } |
925baedd | 37 | |
27cdeb70 | 38 | if (!test_bit(BTRFS_ROOT_REF_COWS, &root->state)) |
6702ed49 | 39 | goto out; |
5f39d397 | 40 | |
6702ed49 CM |
41 | path = btrfs_alloc_path(); |
42 | if (!path) | |
43 | return -ENOMEM; | |
44 | ||
5f39d397 | 45 | level = btrfs_header_level(root->node); |
0f1ebbd1 | 46 | |
d397712b | 47 | if (level == 0) |
6702ed49 | 48 | goto out; |
d397712b | 49 | |
6702ed49 | 50 | if (root->defrag_progress.objectid == 0) { |
e7a84565 | 51 | struct extent_buffer *root_node; |
0ef3e66b CM |
52 | u32 nritems; |
53 | ||
e7a84565 | 54 | root_node = btrfs_lock_root_node(root); |
8bead258 | 55 | btrfs_set_lock_blocking_write(root_node); |
e7a84565 | 56 | nritems = btrfs_header_nritems(root_node); |
0ef3e66b CM |
57 | root->defrag_max.objectid = 0; |
58 | /* from above we know this is not a leaf */ | |
e7a84565 | 59 | btrfs_node_key_to_cpu(root_node, &root->defrag_max, |
0ef3e66b | 60 | nritems - 1); |
e7a84565 CM |
61 | btrfs_tree_unlock(root_node); |
62 | free_extent_buffer(root_node); | |
63 | memset(&key, 0, sizeof(key)); | |
6702ed49 | 64 | } else { |
e7a84565 | 65 | memcpy(&key, &root->defrag_progress, sizeof(key)); |
6702ed49 CM |
66 | } |
67 | ||
e7a84565 | 68 | path->keep_locks = 1; |
3f157a2f | 69 | |
7c829b72 | 70 | ret = btrfs_search_forward(root, &key, path, BTRFS_OLDEST_GENERATION); |
3f157a2f CM |
71 | if (ret < 0) |
72 | goto out; | |
73 | if (ret > 0) { | |
74 | ret = 0; | |
75 | goto out; | |
76 | } | |
b3b4aa74 | 77 | btrfs_release_path(path); |
0376374a FM |
78 | /* |
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). | |
82 | */ | |
83 | path->lowest_level = 1; | |
e7a84565 | 84 | wret = btrfs_search_slot(trans, root, &key, path, 0, 1); |
6702ed49 | 85 | |
e7a84565 CM |
86 | if (wret < 0) { |
87 | ret = wret; | |
88 | goto out; | |
89 | } | |
90 | if (!path->nodes[1]) { | |
91 | ret = 0; | |
92 | goto out; | |
93 | } | |
0376374a FM |
94 | /* |
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 | |
97 | * path->slots[1]. | |
98 | */ | |
99 | BUG_ON(path->locks[1] == 0); | |
e7a84565 CM |
100 | ret = btrfs_realloc_node(trans, root, |
101 | path->nodes[1], 0, | |
de78b51a | 102 | &last_ret, |
e7a84565 | 103 | &root->defrag_progress); |
8929ecfa YZ |
104 | if (ret) { |
105 | WARN_ON(ret == -EAGAIN); | |
106 | goto out; | |
107 | } | |
0376374a FM |
108 | /* |
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. | |
116 | */ | |
117 | path->slots[1] = btrfs_header_nritems(path->nodes[1]); | |
118 | next_key_ret = btrfs_find_next_key(root, path, &key, 1, | |
7c829b72 | 119 | BTRFS_OLDEST_GENERATION); |
e7a84565 CM |
120 | if (next_key_ret == 0) { |
121 | memcpy(&root->defrag_progress, &key, sizeof(key)); | |
122 | ret = -EAGAIN; | |
6702ed49 | 123 | } |
6702ed49 | 124 | out: |
527afb44 | 125 | btrfs_free_path(path); |
0ef3e66b CM |
126 | if (ret == -EAGAIN) { |
127 | if (root->defrag_max.objectid > root->defrag_progress.objectid) | |
128 | goto done; | |
129 | if (root->defrag_max.type > root->defrag_progress.type) | |
130 | goto done; | |
131 | if (root->defrag_max.offset > root->defrag_progress.offset) | |
132 | goto done; | |
133 | ret = 0; | |
134 | } | |
135 | done: | |
6702ed49 CM |
136 | if (ret != -EAGAIN) { |
137 | memset(&root->defrag_progress, 0, | |
138 | sizeof(root->defrag_progress)); | |
3f157a2f | 139 | root->defrag_trans_start = trans->transid; |
6702ed49 CM |
140 | } |
141 | return ret; | |
142 | } |