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 /* defrag all the leaves in a given btree. If cache_only == 1, don't read
27 * things from disk, otherwise read all the leaves and try to get key order to
28 * better reflect disk order
29 */
30
btrfs_defrag_leaves(struct btrfs_trans_handle * trans,struct btrfs_root * root,int cache_only)31 int btrfs_defrag_leaves(struct btrfs_trans_handle *trans,
32 struct btrfs_root *root, int cache_only)
33 {
34 struct btrfs_path *path = NULL;
35 struct btrfs_key key;
36 int ret = 0;
37 int wret;
38 int level;
39 int is_extent = 0;
40 int next_key_ret = 0;
41 u64 last_ret = 0;
42 u64 min_trans = 0;
43
44 if (cache_only)
45 goto out;
46
47 if (root->fs_info->extent_root == root) {
48 /*
49 * there's recursion here right now in the tree locking,
50 * we can't defrag the extent root without deadlock
51 */
52 goto out;
53 }
54
55 if (root->ref_cows == 0 && !is_extent)
56 goto out;
57
58 if (btrfs_test_opt(root, SSD))
59 goto out;
60
61 path = btrfs_alloc_path();
62 if (!path)
63 return -ENOMEM;
64
65 level = btrfs_header_level(root->node);
66
67 if (level == 0)
68 goto out;
69
70 if (root->defrag_progress.objectid == 0) {
71 struct extent_buffer *root_node;
72 u32 nritems;
73
74 root_node = btrfs_lock_root_node(root);
75 btrfs_set_lock_blocking(root_node);
76 nritems = btrfs_header_nritems(root_node);
77 root->defrag_max.objectid = 0;
78 /* from above we know this is not a leaf */
79 btrfs_node_key_to_cpu(root_node, &root->defrag_max,
80 nritems - 1);
81 btrfs_tree_unlock(root_node);
82 free_extent_buffer(root_node);
83 memset(&key, 0, sizeof(key));
84 } else {
85 memcpy(&key, &root->defrag_progress, sizeof(key));
86 }
87
88 path->keep_locks = 1;
89 if (cache_only)
90 min_trans = root->defrag_trans_start;
91
92 ret = btrfs_search_forward(root, &key, NULL, path,
93 cache_only, min_trans);
94 if (ret < 0)
95 goto out;
96 if (ret > 0) {
97 ret = 0;
98 goto out;
99 }
100 btrfs_release_path(path);
101 wret = btrfs_search_slot(trans, root, &key, path, 0, 1);
102
103 if (wret < 0) {
104 ret = wret;
105 goto out;
106 }
107 if (!path->nodes[1]) {
108 ret = 0;
109 goto out;
110 }
111 path->slots[1] = btrfs_header_nritems(path->nodes[1]);
112 next_key_ret = btrfs_find_next_key(root, path, &key, 1, cache_only,
113 min_trans);
114 ret = btrfs_realloc_node(trans, root,
115 path->nodes[1], 0,
116 cache_only, &last_ret,
117 &root->defrag_progress);
118 if (ret) {
119 WARN_ON(ret == -EAGAIN);
120 goto out;
121 }
122 if (next_key_ret == 0) {
123 memcpy(&root->defrag_progress, &key, sizeof(key));
124 ret = -EAGAIN;
125 }
126 out:
127 if (path)
128 btrfs_free_path(path);
129 if (ret == -EAGAIN) {
130 if (root->defrag_max.objectid > root->defrag_progress.objectid)
131 goto done;
132 if (root->defrag_max.type > root->defrag_progress.type)
133 goto done;
134 if (root->defrag_max.offset > root->defrag_progress.offset)
135 goto done;
136 ret = 0;
137 }
138 done:
139 if (ret != -EAGAIN) {
140 memset(&root->defrag_progress, 0,
141 sizeof(root->defrag_progress));
142 root->defrag_trans_start = trans->transid;
143 }
144 return ret;
145 }
146