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 if (btrfs_test_opt(root, SSD))
56 goto out;
57
58 path = btrfs_alloc_path();
59 if (!path)
60 return -ENOMEM;
61
62 level = btrfs_header_level(root->node);
63
64 if (level == 0)
65 goto out;
66
67 if (root->defrag_progress.objectid == 0) {
68 struct extent_buffer *root_node;
69 u32 nritems;
70
71 root_node = btrfs_lock_root_node(root);
72 btrfs_set_lock_blocking(root_node);
73 nritems = btrfs_header_nritems(root_node);
74 root->defrag_max.objectid = 0;
75 /* from above we know this is not a leaf */
76 btrfs_node_key_to_cpu(root_node, &root->defrag_max,
77 nritems - 1);
78 btrfs_tree_unlock(root_node);
79 free_extent_buffer(root_node);
80 memset(&key, 0, sizeof(key));
81 } else {
82 memcpy(&key, &root->defrag_progress, sizeof(key));
83 }
84
85 path->keep_locks = 1;
86
87 ret = btrfs_search_forward(root, &key, path, min_trans);
88 if (ret < 0)
89 goto out;
90 if (ret > 0) {
91 ret = 0;
92 goto out;
93 }
94 btrfs_release_path(path);
95 wret = btrfs_search_slot(trans, root, &key, path, 0, 1);
96
97 if (wret < 0) {
98 ret = wret;
99 goto out;
100 }
101 if (!path->nodes[1]) {
102 ret = 0;
103 goto out;
104 }
105 path->slots[1] = btrfs_header_nritems(path->nodes[1]);
106 next_key_ret = btrfs_find_next_key(root, path, &key, 1,
107 min_trans);
108 ret = btrfs_realloc_node(trans, root,
109 path->nodes[1], 0,
110 &last_ret,
111 &root->defrag_progress);
112 if (ret) {
113 WARN_ON(ret == -EAGAIN);
114 goto out;
115 }
116 if (next_key_ret == 0) {
117 memcpy(&root->defrag_progress, &key, sizeof(key));
118 ret = -EAGAIN;
119 }
120 out:
121 if (path)
122 btrfs_free_path(path);
123 if (ret == -EAGAIN) {
124 if (root->defrag_max.objectid > root->defrag_progress.objectid)
125 goto done;
126 if (root->defrag_max.type > root->defrag_progress.type)
127 goto done;
128 if (root->defrag_max.offset > root->defrag_progress.offset)
129 goto done;
130 ret = 0;
131 }
132 done:
133 if (ret != -EAGAIN) {
134 memset(&root->defrag_progress, 0,
135 sizeof(root->defrag_progress));
136 root->defrag_trans_start = trans->transid;
137 }
138 return ret;
139 }
140