ALSA: hda-intel - fix wallclk variable update and condition
[pandora-kernel.git] / fs / btrfs / export.c
1 #include <linux/fs.h>
2 #include <linux/types.h>
3 #include "ctree.h"
4 #include "disk-io.h"
5 #include "btrfs_inode.h"
6 #include "print-tree.h"
7 #include "export.h"
8 #include "compat.h"
9
10 #define BTRFS_FID_SIZE_NON_CONNECTABLE (offsetof(struct btrfs_fid, \
11                                                  parent_objectid) / 4)
12 #define BTRFS_FID_SIZE_CONNECTABLE (offsetof(struct btrfs_fid, \
13                                              parent_root_objectid) / 4)
14 #define BTRFS_FID_SIZE_CONNECTABLE_ROOT (sizeof(struct btrfs_fid) / 4)
15
16 static int btrfs_encode_fh(struct dentry *dentry, u32 *fh, int *max_len,
17                            int connectable)
18 {
19         struct btrfs_fid *fid = (struct btrfs_fid *)fh;
20         struct inode *inode = dentry->d_inode;
21         int len = *max_len;
22         int type;
23
24         if ((len < BTRFS_FID_SIZE_NON_CONNECTABLE) ||
25             (connectable && len < BTRFS_FID_SIZE_CONNECTABLE))
26                 return 255;
27
28         len  = BTRFS_FID_SIZE_NON_CONNECTABLE;
29         type = FILEID_BTRFS_WITHOUT_PARENT;
30
31         fid->objectid = inode->i_ino;
32         fid->root_objectid = BTRFS_I(inode)->root->objectid;
33         fid->gen = inode->i_generation;
34
35         if (connectable && !S_ISDIR(inode->i_mode)) {
36                 struct inode *parent;
37                 u64 parent_root_id;
38
39                 spin_lock(&dentry->d_lock);
40
41                 parent = dentry->d_parent->d_inode;
42                 fid->parent_objectid = BTRFS_I(parent)->location.objectid;
43                 fid->parent_gen = parent->i_generation;
44                 parent_root_id = BTRFS_I(parent)->root->objectid;
45
46                 spin_unlock(&dentry->d_lock);
47
48                 if (parent_root_id != fid->root_objectid) {
49                         fid->parent_root_objectid = parent_root_id;
50                         len = BTRFS_FID_SIZE_CONNECTABLE_ROOT;
51                         type = FILEID_BTRFS_WITH_PARENT_ROOT;
52                 } else {
53                         len = BTRFS_FID_SIZE_CONNECTABLE;
54                         type = FILEID_BTRFS_WITH_PARENT;
55                 }
56         }
57
58         *max_len = len;
59         return type;
60 }
61
62 static struct dentry *btrfs_get_dentry(struct super_block *sb, u64 objectid,
63                                        u64 root_objectid, u32 generation,
64                                        int check_generation)
65 {
66         struct btrfs_fs_info *fs_info = btrfs_sb(sb)->fs_info;
67         struct btrfs_root *root;
68         struct dentry *dentry;
69         struct inode *inode;
70         struct btrfs_key key;
71         int index;
72         int err = 0;
73
74         if (objectid < BTRFS_FIRST_FREE_OBJECTID)
75                 return ERR_PTR(-ESTALE);
76
77         key.objectid = root_objectid;
78         btrfs_set_key_type(&key, BTRFS_ROOT_ITEM_KEY);
79         key.offset = (u64)-1;
80
81         index = srcu_read_lock(&fs_info->subvol_srcu);
82
83         root = btrfs_read_fs_root_no_name(fs_info, &key);
84         if (IS_ERR(root)) {
85                 err = PTR_ERR(root);
86                 goto fail;
87         }
88
89         if (btrfs_root_refs(&root->root_item) == 0) {
90                 err = -ENOENT;
91                 goto fail;
92         }
93
94         key.objectid = objectid;
95         btrfs_set_key_type(&key, BTRFS_INODE_ITEM_KEY);
96         key.offset = 0;
97
98         inode = btrfs_iget(sb, &key, root, NULL);
99         if (IS_ERR(inode)) {
100                 err = PTR_ERR(inode);
101                 goto fail;
102         }
103
104         srcu_read_unlock(&fs_info->subvol_srcu, index);
105
106         if (check_generation && generation != inode->i_generation) {
107                 iput(inode);
108                 return ERR_PTR(-ESTALE);
109         }
110
111         dentry = d_obtain_alias(inode);
112         if (!IS_ERR(dentry))
113                 dentry->d_op = &btrfs_dentry_operations;
114         return dentry;
115 fail:
116         srcu_read_unlock(&fs_info->subvol_srcu, index);
117         return ERR_PTR(err);
118 }
119
120 static struct dentry *btrfs_fh_to_parent(struct super_block *sb, struct fid *fh,
121                                          int fh_len, int fh_type)
122 {
123         struct btrfs_fid *fid = (struct btrfs_fid *) fh;
124         u64 objectid, root_objectid;
125         u32 generation;
126
127         if (fh_type == FILEID_BTRFS_WITH_PARENT) {
128                 if (fh_len !=  BTRFS_FID_SIZE_CONNECTABLE)
129                         return NULL;
130                 root_objectid = fid->root_objectid;
131         } else if (fh_type == FILEID_BTRFS_WITH_PARENT_ROOT) {
132                 if (fh_len != BTRFS_FID_SIZE_CONNECTABLE_ROOT)
133                         return NULL;
134                 root_objectid = fid->parent_root_objectid;
135         } else
136                 return NULL;
137
138         objectid = fid->parent_objectid;
139         generation = fid->parent_gen;
140
141         return btrfs_get_dentry(sb, objectid, root_objectid, generation, 1);
142 }
143
144 static struct dentry *btrfs_fh_to_dentry(struct super_block *sb, struct fid *fh,
145                                          int fh_len, int fh_type)
146 {
147         struct btrfs_fid *fid = (struct btrfs_fid *) fh;
148         u64 objectid, root_objectid;
149         u32 generation;
150
151         if ((fh_type != FILEID_BTRFS_WITH_PARENT ||
152              fh_len != BTRFS_FID_SIZE_CONNECTABLE) &&
153             (fh_type != FILEID_BTRFS_WITH_PARENT_ROOT ||
154              fh_len != BTRFS_FID_SIZE_CONNECTABLE_ROOT) &&
155             (fh_type != FILEID_BTRFS_WITHOUT_PARENT ||
156              fh_len != BTRFS_FID_SIZE_NON_CONNECTABLE))
157                 return NULL;
158
159         objectid = fid->objectid;
160         root_objectid = fid->root_objectid;
161         generation = fid->gen;
162
163         return btrfs_get_dentry(sb, objectid, root_objectid, generation, 1);
164 }
165
166 static struct dentry *btrfs_get_parent(struct dentry *child)
167 {
168         struct inode *dir = child->d_inode;
169         static struct dentry *dentry;
170         struct btrfs_root *root = BTRFS_I(dir)->root;
171         struct btrfs_path *path;
172         struct extent_buffer *leaf;
173         struct btrfs_root_ref *ref;
174         struct btrfs_key key;
175         struct btrfs_key found_key;
176         int ret;
177
178         path = btrfs_alloc_path();
179
180         if (dir->i_ino == BTRFS_FIRST_FREE_OBJECTID) {
181                 key.objectid = root->root_key.objectid;
182                 key.type = BTRFS_ROOT_BACKREF_KEY;
183                 key.offset = (u64)-1;
184                 root = root->fs_info->tree_root;
185         } else {
186                 key.objectid = dir->i_ino;
187                 key.type = BTRFS_INODE_REF_KEY;
188                 key.offset = (u64)-1;
189         }
190
191         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
192         if (ret < 0)
193                 goto fail;
194
195         BUG_ON(ret == 0);
196         if (path->slots[0] == 0) {
197                 ret = -ENOENT;
198                 goto fail;
199         }
200
201         path->slots[0]--;
202         leaf = path->nodes[0];
203
204         btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
205         if (found_key.objectid != key.objectid || found_key.type != key.type) {
206                 ret = -ENOENT;
207                 goto fail;
208         }
209
210         if (found_key.type == BTRFS_ROOT_BACKREF_KEY) {
211                 ref = btrfs_item_ptr(leaf, path->slots[0],
212                                      struct btrfs_root_ref);
213                 key.objectid = btrfs_root_ref_dirid(leaf, ref);
214         } else {
215                 key.objectid = found_key.offset;
216         }
217         btrfs_free_path(path);
218
219         if (found_key.type == BTRFS_ROOT_BACKREF_KEY) {
220                 return btrfs_get_dentry(root->fs_info->sb, key.objectid,
221                                         found_key.offset, 0, 0);
222         }
223
224         key.type = BTRFS_INODE_ITEM_KEY;
225         key.offset = 0;
226         dentry = d_obtain_alias(btrfs_iget(root->fs_info->sb, &key, root, NULL));
227         if (!IS_ERR(dentry))
228                 dentry->d_op = &btrfs_dentry_operations;
229         return dentry;
230 fail:
231         btrfs_free_path(path);
232         return ERR_PTR(ret);
233 }
234
235 const struct export_operations btrfs_export_ops = {
236         .encode_fh      = btrfs_encode_fh,
237         .fh_to_dentry   = btrfs_fh_to_dentry,
238         .fh_to_parent   = btrfs_fh_to_parent,
239         .get_parent     = btrfs_get_parent,
240 };