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 is_extent = 0;
41 int next_key_ret = 0;
42 u64 last_ret = 0;
43 u64 min_trans = 0;
44
45 if (root->fs_info->extent_root == root) {
46 /*
47 * there's recursion here right now in the tree locking,
48 * we can't defrag the extent root without deadlock
49 */
50 goto out;
51 }
52
53 if (root->ref_cows == 0 && !is_extent)
54 goto out;
55
56 if (btrfs_test_opt(root, SSD))
57 goto out;
58
59 path = btrfs_alloc_path();
60 if (!path)
61 return -ENOMEM;
62
63 level = btrfs_header_level(root->node);
64
65 if (level == 0)
66 goto out;
67
68 if (root->defrag_progress.objectid == 0) {
69 struct extent_buffer *root_node;
70 u32 nritems;
71
72 root_node = btrfs_lock_root_node(root);
73 btrfs_set_lock_blocking(root_node);
74 nritems = btrfs_header_nritems(root_node);
75 root->defrag_max.objectid = 0;
76 /* from above we know this is not a leaf */
77 btrfs_node_key_to_cpu(root_node, &root->defrag_max,
78 nritems - 1);
79 btrfs_tree_unlock(root_node);
80 free_extent_buffer(root_node);
81 memset(&key, 0, sizeof(key));
82 } else {
83 memcpy(&key, &root->defrag_progress, sizeof(key));
84 }
85
86 path->keep_locks = 1;
87
88 ret = btrfs_search_forward(root, &key, NULL, path, min_trans);
89 if (ret < 0)
90 goto out;
91 if (ret > 0) {
92 ret = 0;
93 goto out;
94 }
95 btrfs_release_path(path);
96 wret = btrfs_search_slot(trans, root, &key, path, 0, 1);
97
98 if (wret < 0) {
99 ret = wret;
100 goto out;
101 }
102 if (!path->nodes[1]) {
103 ret = 0;
104 goto out;
105 }
106 path->slots[1] = btrfs_header_nritems(path->nodes[1]);
107 next_key_ret = btrfs_find_next_key(root, path, &key, 1,
108 min_trans);
109 ret = btrfs_realloc_node(trans, root,
110 path->nodes[1], 0,
111 &last_ret,
112 &root->defrag_progress);
113 if (ret) {
114 WARN_ON(ret == -EAGAIN);
115 goto out;
116 }
117 if (next_key_ret == 0) {
118 memcpy(&root->defrag_progress, &key, sizeof(key));
119 ret = -EAGAIN;
120 }
121 out:
122 if (path)
123 btrfs_free_path(path);
124 if (ret == -EAGAIN) {
125 if (root->defrag_max.objectid > root->defrag_progress.objectid)
126 goto done;
127 if (root->defrag_max.type > root->defrag_progress.type)
128 goto done;
129 if (root->defrag_max.offset > root->defrag_progress.offset)
130 goto done;
131 ret = 0;
132 }
133 done:
134 if (ret != -EAGAIN) {
135 memset(&root->defrag_progress, 0,
136 sizeof(root->defrag_progress));
137 root->defrag_trans_start = trans->transid;
138 }
139 return ret;
140 }
141