Btrfs: calc file extent num_bytes correctly in file clone
[linux-2.6.git] / fs / btrfs / tree-defrag.c
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
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 }