Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/sparc-2.6
[linux-2.6.git] / fs / btrfs / inode-item.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 "ctree.h"
20 #include "disk-io.h"
21 #include "transaction.h"
22
23 static int find_name_in_backref(struct btrfs_path *path, const char *name,
24                          int name_len, struct btrfs_inode_ref **ref_ret)
25 {
26         struct extent_buffer *leaf;
27         struct btrfs_inode_ref *ref;
28         unsigned long ptr;
29         unsigned long name_ptr;
30         u32 item_size;
31         u32 cur_offset = 0;
32         int len;
33
34         leaf = path->nodes[0];
35         item_size = btrfs_item_size_nr(leaf, path->slots[0]);
36         ptr = btrfs_item_ptr_offset(leaf, path->slots[0]);
37         while (cur_offset < item_size) {
38                 ref = (struct btrfs_inode_ref *)(ptr + cur_offset);
39                 len = btrfs_inode_ref_name_len(leaf, ref);
40                 name_ptr = (unsigned long)(ref + 1);
41                 cur_offset += len + sizeof(*ref);
42                 if (len != name_len)
43                         continue;
44                 if (memcmp_extent_buffer(leaf, name, name_ptr, name_len) == 0) {
45                         *ref_ret = ref;
46                         return 1;
47                 }
48         }
49         return 0;
50 }
51
52 int btrfs_del_inode_ref(struct btrfs_trans_handle *trans,
53                            struct btrfs_root *root,
54                            const char *name, int name_len,
55                            u64 inode_objectid, u64 ref_objectid, u64 *index)
56 {
57         struct btrfs_path *path;
58         struct btrfs_key key;
59         struct btrfs_inode_ref *ref;
60         struct extent_buffer *leaf;
61         unsigned long ptr;
62         unsigned long item_start;
63         u32 item_size;
64         u32 sub_item_len;
65         int ret;
66         int del_len = name_len + sizeof(*ref);
67
68         key.objectid = inode_objectid;
69         key.offset = ref_objectid;
70         btrfs_set_key_type(&key, BTRFS_INODE_REF_KEY);
71
72         path = btrfs_alloc_path();
73         if (!path)
74                 return -ENOMEM;
75
76         path->leave_spinning = 1;
77
78         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
79         if (ret > 0) {
80                 ret = -ENOENT;
81                 goto out;
82         } else if (ret < 0) {
83                 goto out;
84         }
85         if (!find_name_in_backref(path, name, name_len, &ref)) {
86                 ret = -ENOENT;
87                 goto out;
88         }
89         leaf = path->nodes[0];
90         item_size = btrfs_item_size_nr(leaf, path->slots[0]);
91
92         if (index)
93                 *index = btrfs_inode_ref_index(leaf, ref);
94
95         if (del_len == item_size) {
96                 ret = btrfs_del_item(trans, root, path);
97                 goto out;
98         }
99         ptr = (unsigned long)ref;
100         sub_item_len = name_len + sizeof(*ref);
101         item_start = btrfs_item_ptr_offset(leaf, path->slots[0]);
102         memmove_extent_buffer(leaf, ptr, ptr + sub_item_len,
103                               item_size - (ptr + sub_item_len - item_start));
104         ret = btrfs_truncate_item(trans, root, path,
105                                   item_size - sub_item_len, 1);
106         BUG_ON(ret);
107 out:
108         btrfs_free_path(path);
109         return ret;
110 }
111
112 int btrfs_insert_inode_ref(struct btrfs_trans_handle *trans,
113                            struct btrfs_root *root,
114                            const char *name, int name_len,
115                            u64 inode_objectid, u64 ref_objectid, u64 index)
116 {
117         struct btrfs_path *path;
118         struct btrfs_key key;
119         struct btrfs_inode_ref *ref;
120         unsigned long ptr;
121         int ret;
122         int ins_len = name_len + sizeof(*ref);
123
124         key.objectid = inode_objectid;
125         key.offset = ref_objectid;
126         btrfs_set_key_type(&key, BTRFS_INODE_REF_KEY);
127
128         path = btrfs_alloc_path();
129         if (!path)
130                 return -ENOMEM;
131
132         path->leave_spinning = 1;
133         ret = btrfs_insert_empty_item(trans, root, path, &key,
134                                       ins_len);
135         if (ret == -EEXIST) {
136                 u32 old_size;
137
138                 if (find_name_in_backref(path, name, name_len, &ref))
139                         goto out;
140
141                 old_size = btrfs_item_size_nr(path->nodes[0], path->slots[0]);
142                 ret = btrfs_extend_item(trans, root, path, ins_len);
143                 BUG_ON(ret);
144                 ref = btrfs_item_ptr(path->nodes[0], path->slots[0],
145                                      struct btrfs_inode_ref);
146                 ref = (struct btrfs_inode_ref *)((unsigned long)ref + old_size);
147                 btrfs_set_inode_ref_name_len(path->nodes[0], ref, name_len);
148                 btrfs_set_inode_ref_index(path->nodes[0], ref, index);
149                 ptr = (unsigned long)(ref + 1);
150                 ret = 0;
151         } else if (ret < 0) {
152                 if (ret == -EOVERFLOW)
153                         ret = -EMLINK;
154                 goto out;
155         } else {
156                 ref = btrfs_item_ptr(path->nodes[0], path->slots[0],
157                                      struct btrfs_inode_ref);
158                 btrfs_set_inode_ref_name_len(path->nodes[0], ref, name_len);
159                 btrfs_set_inode_ref_index(path->nodes[0], ref, index);
160                 ptr = (unsigned long)(ref + 1);
161         }
162         write_extent_buffer(path->nodes[0], name, ptr, name_len);
163         btrfs_mark_buffer_dirty(path->nodes[0]);
164
165 out:
166         btrfs_free_path(path);
167         return ret;
168 }
169
170 int btrfs_insert_empty_inode(struct btrfs_trans_handle *trans,
171                              struct btrfs_root *root,
172                              struct btrfs_path *path, u64 objectid)
173 {
174         struct btrfs_key key;
175         int ret;
176         key.objectid = objectid;
177         btrfs_set_key_type(&key, BTRFS_INODE_ITEM_KEY);
178         key.offset = 0;
179
180         ret = btrfs_insert_empty_item(trans, root, path, &key,
181                                       sizeof(struct btrfs_inode_item));
182         return ret;
183 }
184
185 int btrfs_lookup_inode(struct btrfs_trans_handle *trans, struct btrfs_root
186                        *root, struct btrfs_path *path,
187                        struct btrfs_key *location, int mod)
188 {
189         int ins_len = mod < 0 ? -1 : 0;
190         int cow = mod != 0;
191         int ret;
192         int slot;
193         struct extent_buffer *leaf;
194         struct btrfs_key found_key;
195
196         ret = btrfs_search_slot(trans, root, location, path, ins_len, cow);
197         if (ret > 0 && btrfs_key_type(location) == BTRFS_ROOT_ITEM_KEY &&
198             location->offset == (u64)-1 && path->slots[0] != 0) {
199                 slot = path->slots[0] - 1;
200                 leaf = path->nodes[0];
201                 btrfs_item_key_to_cpu(leaf, &found_key, slot);
202                 if (found_key.objectid == location->objectid &&
203                     btrfs_key_type(&found_key) == btrfs_key_type(location)) {
204                         path->slots[0]--;
205                         return 0;
206                 }
207         }
208         return ret;
209 }