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-rw-r--r--fs/btrfs/tree-defrag.c222
1 files changed, 222 insertions, 0 deletions
diff --git a/fs/btrfs/tree-defrag.c b/fs/btrfs/tree-defrag.c
new file mode 100644
index 000000000000..15d0a486fb59
--- /dev/null
+++ b/fs/btrfs/tree-defrag.c
@@ -0,0 +1,222 @@
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
25static void reada_defrag(struct btrfs_root *root,
26 struct btrfs_node *node)
27{
28 int i;
29 u32 nritems;
30 u64 blocknr;
31 int ret;
32
33 nritems = btrfs_header_nritems(&node->header);
34 for (i = 0; i < nritems; i++) {
35 blocknr = btrfs_node_blockptr(node, i);
36 ret = readahead_tree_block(root, blocknr);
37 if (ret)
38 break;
39 }
40}
41
42static int defrag_walk_down(struct btrfs_trans_handle *trans,
43 struct btrfs_root *root,
44 struct btrfs_path *path, int *level,
45 int cache_only)
46{
47 struct buffer_head *next;
48 struct buffer_head *cur;
49 u64 blocknr;
50 int ret = 0;
51
52 WARN_ON(*level < 0);
53 WARN_ON(*level >= BTRFS_MAX_LEVEL);
54
55 while(*level > 0) {
56 WARN_ON(*level < 0);
57 WARN_ON(*level >= BTRFS_MAX_LEVEL);
58 cur = path->nodes[*level];
59
60 if (!cache_only && *level > 1 && path->slots[*level] == 0)
61 reada_defrag(root, btrfs_buffer_node(cur));
62
63 if (btrfs_header_level(btrfs_buffer_header(cur)) != *level)
64 WARN_ON(1);
65
66 if (path->slots[*level] >=
67 btrfs_header_nritems(btrfs_buffer_header(cur)))
68 break;
69
70 if (*level == 1) {
71 ret = btrfs_realloc_node(trans, root,
72 path->nodes[*level],
73 cache_only);
74 break;
75 }
76 blocknr = btrfs_node_blockptr(btrfs_buffer_node(cur),
77 path->slots[*level]);
78
79 if (cache_only) {
80 next = btrfs_find_tree_block(root, blocknr);
81 if (!next || !buffer_uptodate(next) ||
82 buffer_locked(next)) {
83 brelse(next);
84 path->slots[*level]++;
85 continue;
86 }
87 } else {
88 next = read_tree_block(root, blocknr);
89 }
90 ret = btrfs_cow_block(trans, root, next, path->nodes[*level],
91 path->slots[*level], &next);
92 BUG_ON(ret);
93 ret = btrfs_realloc_node(trans, root, next, cache_only);
94 BUG_ON(ret);
95 WARN_ON(*level <= 0);
96 if (path->nodes[*level-1])
97 btrfs_block_release(root, path->nodes[*level-1]);
98 path->nodes[*level-1] = next;
99 *level = btrfs_header_level(btrfs_buffer_header(next));
100 path->slots[*level] = 0;
101 }
102 WARN_ON(*level < 0);
103 WARN_ON(*level >= BTRFS_MAX_LEVEL);
104 btrfs_block_release(root, path->nodes[*level]);
105 path->nodes[*level] = NULL;
106 *level += 1;
107 WARN_ON(ret);
108 return 0;
109}
110
111static int defrag_walk_up(struct btrfs_trans_handle *trans,
112 struct btrfs_root *root,
113 struct btrfs_path *path, int *level,
114 int cache_only)
115{
116 int i;
117 int slot;
118 struct btrfs_node *node;
119
120 for(i = *level; i < BTRFS_MAX_LEVEL - 1 && path->nodes[i]; i++) {
121 slot = path->slots[i];
122 if (slot < btrfs_header_nritems(
123 btrfs_buffer_header(path->nodes[i])) - 1) {
124 path->slots[i]++;
125 *level = i;
126 node = btrfs_buffer_node(path->nodes[i]);
127 WARN_ON(i == 0);
128 btrfs_disk_key_to_cpu(&root->defrag_progress,
129 &node->ptrs[path->slots[i]].key);
130 root->defrag_level = i;
131 return 0;
132 } else {
133 btrfs_block_release(root, path->nodes[*level]);
134 path->nodes[*level] = NULL;
135 *level = i + 1;
136 }
137 }
138 return 1;
139}
140
141int btrfs_defrag_leaves(struct btrfs_trans_handle *trans,
142 struct btrfs_root *root, int cache_only)
143{
144 struct btrfs_path *path = NULL;
145 struct buffer_head *tmp;
146 int ret = 0;
147 int wret;
148 int level;
149 int orig_level;
150 int i;
151 int num_runs = 0;
152
153 if (root->ref_cows == 0) {
154 goto out;
155 }
156 path = btrfs_alloc_path();
157 if (!path)
158 return -ENOMEM;
159
160 level = btrfs_header_level(btrfs_buffer_header(root->node));
161 orig_level = level;
162 if (level == 0) {
163 goto out;
164 }
165 if (root->defrag_progress.objectid == 0) {
166 get_bh(root->node);
167 ret = btrfs_cow_block(trans, root, root->node, NULL, 0, &tmp);
168 BUG_ON(ret);
169 ret = btrfs_realloc_node(trans, root, root->node, cache_only);
170 BUG_ON(ret);
171 path->nodes[level] = root->node;
172 path->slots[level] = 0;
173 } else {
174 level = root->defrag_level;
175 path->lowest_level = level;
176 wret = btrfs_search_slot(trans, root, &root->defrag_progress,
177 path, 0, 1);
178
179 if (wret < 0) {
180 ret = wret;
181 goto out;
182 }
183 while(level > 0 && !path->nodes[level])
184 level--;
185 if (!path->nodes[level]) {
186 ret = 0;
187 goto out;
188 }
189 }
190
191 while(1) {
192 wret = defrag_walk_down(trans, root, path, &level, cache_only);
193 if (wret > 0)
194 break;
195 if (wret < 0)
196 ret = wret;
197
198 wret = defrag_walk_up(trans, root, path, &level, cache_only);
199 if (wret > 0)
200 break;
201 if (wret < 0)
202 ret = wret;
203 if (num_runs++ > 8) {
204 ret = -EAGAIN;
205 break;
206 }
207 }
208 for (i = 0; i <= orig_level; i++) {
209 if (path->nodes[i]) {
210 btrfs_block_release(root, path->nodes[i]);
211 path->nodes[i] = 0;
212 }
213 }
214out:
215 if (path)
216 btrfs_free_path(path);
217 if (ret != -EAGAIN) {
218 memset(&root->defrag_progress, 0,
219 sizeof(root->defrag_progress));
220 }
221 return ret;
222}
generated by cgit v1.2.2 (git 2.25.0) at 2024-12-30 11:16:50 -0500