1 /*
2 * Copyright (C) 2007 Oracle. All rights reserved.
3 *
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU General Public
6 * License v2 as published by the Free Software Foundation.
7 *
8 * This program is distributed in the hope that it will be useful,
9 * but WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
11 * General Public License for more details.
12 *
13 * You should have received a copy of the GNU General Public
14 * License along with this program; if not, write to the
15 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
16 * Boston, MA 021110-1307, USA.
17 */
18
19 #include <linux/sched.h>
20 #include "ctree.h"
21 #include "disk-io.h"
22 #include "print-tree.h"
23 #include "transaction.h"
24 #include "locking.h"
25
26 /*
27 * Defrag all the leaves in a given btree.
28 * Read all the leaves and try to get key order to
29 * better reflect disk order
30 */
31
btrfs_defrag_leaves(struct btrfs_trans_handle * trans,struct btrfs_root * root)32 int btrfs_defrag_leaves(struct btrfs_trans_handle *trans,
33 struct btrfs_root *root)
34 {
35 struct btrfs_path *path = NULL;
36 struct btrfs_key key;
37 int ret = 0;
38 int wret;
39 int level;
40 int next_key_ret = 0;
41 u64 last_ret = 0;
42 u64 min_trans = 0;
43
44 if (root->fs_info->extent_root == root) {
45 /*
46 * there's recursion here right now in the tree locking,
47 * we can't defrag the extent root without deadlock
48 */
49 goto out;
50 }
51
52 if (!test_bit(BTRFS_ROOT_REF_COWS, &root->state))
53 goto out;
54
55 path = btrfs_alloc_path();
56 if (!path)
57 return -ENOMEM;
58
59 level = btrfs_header_level(root->node);
60
61 if (level == 0)
62 goto out;
63
64 if (root->defrag_progress.objectid == 0) {
65 struct extent_buffer *root_node;
66 u32 nritems;
67
68 root_node = btrfs_lock_root_node(root);
69 btrfs_set_lock_blocking(root_node);
70 nritems = btrfs_header_nritems(root_node);
71 root->defrag_max.objectid = 0;
72 /* from above we know this is not a leaf */
73 btrfs_node_key_to_cpu(root_node, &root->defrag_max,
74 nritems - 1);
75 btrfs_tree_unlock(root_node);
76 free_extent_buffer(root_node);
77 memset(&key, 0, sizeof(key));
78 } else {
79 memcpy(&key, &root->defrag_progress, sizeof(key));
80 }
81
82 path->keep_locks = 1;
83
84 ret = btrfs_search_forward(root, &key, path, min_trans);
85 if (ret < 0)
86 goto out;
87 if (ret > 0) {
88 ret = 0;
89 goto out;
90 }
91 btrfs_release_path(path);
92 wret = btrfs_search_slot(trans, root, &key, path, 0, 1);
93
94 if (wret < 0) {
95 ret = wret;
96 goto out;
97 }
98 if (!path->nodes[1]) {
99 ret = 0;
100 goto out;
101 }
102 path->slots[1] = btrfs_header_nritems(path->nodes[1]);
103 next_key_ret = btrfs_find_next_key(root, path, &key, 1,
104 min_trans);
105 ret = btrfs_realloc_node(trans, root,
106 path->nodes[1], 0,
107 &last_ret,
108 &root->defrag_progress);
109 if (ret) {
110 WARN_ON(ret == -EAGAIN);
111 goto out;
112 }
113 if (next_key_ret == 0) {
114 memcpy(&root->defrag_progress, &key, sizeof(key));
115 ret = -EAGAIN;
116 }
117 out:
118 btrfs_free_path(path);
119 if (ret == -EAGAIN) {
120 if (root->defrag_max.objectid > root->defrag_progress.objectid)
121 goto done;
122 if (root->defrag_max.type > root->defrag_progress.type)
123 goto done;
124 if (root->defrag_max.offset > root->defrag_progress.offset)
125 goto done;
126 ret = 0;
127 }
128 done:
129 if (ret != -EAGAIN) {
130 memset(&root->defrag_progress, 0,
131 sizeof(root->defrag_progress));
132 root->defrag_trans_start = trans->transid;
133 }
134 return ret;
135 }
136