]>
Commit | Line | Data |
---|---|---|
be6e8dc0 BR |
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 | ||
d397712b CM |
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) | |
be6e8dc0 BR |
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 = BTRFS_I(inode)->location.objectid; | |
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 | { | |
65 | struct btrfs_root *root; | |
66 | struct inode *inode; | |
be6e8dc0 BR |
67 | struct btrfs_key key; |
68 | ||
2d4d9fbd DW |
69 | key.objectid = root_objectid; |
70 | btrfs_set_key_type(&key, BTRFS_ROOT_ITEM_KEY); | |
71 | key.offset = (u64)-1; | |
72 | ||
73 | root = btrfs_read_fs_root_no_name(btrfs_sb(sb)->fs_info, &key); | |
74 | if (IS_ERR(root)) | |
75 | return ERR_CAST(root); | |
76 | ||
be6e8dc0 BR |
77 | key.objectid = objectid; |
78 | btrfs_set_key_type(&key, BTRFS_INODE_ITEM_KEY); | |
79 | key.offset = 0; | |
80 | ||
be6e8dc0 BR |
81 | inode = btrfs_iget(sb, &key, root, NULL); |
82 | if (IS_ERR(inode)) | |
83 | return (void *)inode; | |
84 | ||
85 | if (generation != inode->i_generation) { | |
86 | iput(inode); | |
87 | return ERR_PTR(-ESTALE); | |
88 | } | |
89 | ||
50ec891c | 90 | return d_obtain_alias(inode); |
be6e8dc0 BR |
91 | } |
92 | ||
93 | static struct dentry *btrfs_fh_to_parent(struct super_block *sb, struct fid *fh, | |
94 | int fh_len, int fh_type) | |
95 | { | |
96 | struct btrfs_fid *fid = (struct btrfs_fid *) fh; | |
97 | u64 objectid, root_objectid; | |
98 | u32 generation; | |
99 | ||
100 | if (fh_type == FILEID_BTRFS_WITH_PARENT) { | |
101 | if (fh_len != BTRFS_FID_SIZE_CONNECTABLE) | |
102 | return NULL; | |
103 | root_objectid = fid->root_objectid; | |
104 | } else if (fh_type == FILEID_BTRFS_WITH_PARENT_ROOT) { | |
105 | if (fh_len != BTRFS_FID_SIZE_CONNECTABLE_ROOT) | |
106 | return NULL; | |
107 | root_objectid = fid->parent_root_objectid; | |
108 | } else | |
109 | return NULL; | |
110 | ||
111 | objectid = fid->parent_objectid; | |
112 | generation = fid->parent_gen; | |
113 | ||
114 | return btrfs_get_dentry(sb, objectid, root_objectid, generation); | |
115 | } | |
116 | ||
117 | static struct dentry *btrfs_fh_to_dentry(struct super_block *sb, struct fid *fh, | |
118 | int fh_len, int fh_type) | |
119 | { | |
120 | struct btrfs_fid *fid = (struct btrfs_fid *) fh; | |
121 | u64 objectid, root_objectid; | |
122 | u32 generation; | |
123 | ||
124 | if ((fh_type != FILEID_BTRFS_WITH_PARENT || | |
125 | fh_len != BTRFS_FID_SIZE_CONNECTABLE) && | |
126 | (fh_type != FILEID_BTRFS_WITH_PARENT_ROOT || | |
127 | fh_len != BTRFS_FID_SIZE_CONNECTABLE_ROOT) && | |
128 | (fh_type != FILEID_BTRFS_WITHOUT_PARENT || | |
129 | fh_len != BTRFS_FID_SIZE_NON_CONNECTABLE)) | |
130 | return NULL; | |
131 | ||
132 | objectid = fid->objectid; | |
133 | root_objectid = fid->root_objectid; | |
134 | generation = fid->gen; | |
135 | ||
136 | return btrfs_get_dentry(sb, objectid, root_objectid, generation); | |
137 | } | |
138 | ||
139 | static struct dentry *btrfs_get_parent(struct dentry *child) | |
140 | { | |
141 | struct inode *dir = child->d_inode; | |
be6e8dc0 BR |
142 | struct btrfs_root *root = BTRFS_I(dir)->root; |
143 | struct btrfs_key key; | |
144 | struct btrfs_path *path; | |
145 | struct extent_buffer *leaf; | |
be6e8dc0 BR |
146 | int slot; |
147 | u64 objectid; | |
148 | int ret; | |
149 | ||
150 | path = btrfs_alloc_path(); | |
151 | ||
152 | key.objectid = dir->i_ino; | |
153 | btrfs_set_key_type(&key, BTRFS_INODE_REF_KEY); | |
87acb4ef | 154 | key.offset = (u64)-1; |
be6e8dc0 | 155 | |
87acb4ef | 156 | ret = btrfs_search_slot(NULL, root, &key, path, 0, 0); |
d54a8390 DW |
157 | if (ret < 0) { |
158 | /* Error */ | |
159 | btrfs_free_path(path); | |
160 | return ERR_PTR(ret); | |
161 | } | |
be6e8dc0 BR |
162 | leaf = path->nodes[0]; |
163 | slot = path->slots[0]; | |
d54a8390 DW |
164 | if (ret) { |
165 | /* btrfs_search_slot() returns the slot where we'd want to | |
166 | insert a backref for parent inode #0xFFFFFFFFFFFFFFFF. | |
167 | The _real_ backref, telling us what the parent inode | |
168 | _actually_ is, will be in the slot _before_ the one | |
169 | that btrfs_search_slot() returns. */ | |
170 | if (!slot) { | |
171 | /* Unless there is _no_ key in the tree before... */ | |
172 | btrfs_free_path(path); | |
173 | return ERR_PTR(-EIO); | |
174 | } | |
175 | slot--; | |
be6e8dc0 BR |
176 | } |
177 | ||
87acb4ef | 178 | btrfs_item_key_to_cpu(leaf, &key, slot); |
be6e8dc0 BR |
179 | btrfs_free_path(path); |
180 | ||
be6e8dc0 | 181 | if (key.objectid != dir->i_ino || key.type != BTRFS_INODE_REF_KEY) |
d54a8390 | 182 | return ERR_PTR(-EINVAL); |
be6e8dc0 BR |
183 | |
184 | objectid = key.offset; | |
185 | ||
2d4d9fbd DW |
186 | /* If we are already at the root of a subvol, return the real root */ |
187 | if (objectid == dir->i_ino) | |
188 | return dget(dir->i_sb->s_root); | |
189 | ||
be6e8dc0 BR |
190 | /* Build a new key for the inode item */ |
191 | key.objectid = objectid; | |
192 | btrfs_set_key_type(&key, BTRFS_INODE_ITEM_KEY); | |
193 | key.offset = 0; | |
194 | ||
50ec891c | 195 | return d_obtain_alias(btrfs_iget(root->fs_info->sb, &key, root, NULL)); |
be6e8dc0 BR |
196 | } |
197 | ||
198 | const struct export_operations btrfs_export_ops = { | |
199 | .encode_fh = btrfs_encode_fh, | |
200 | .fh_to_dentry = btrfs_fh_to_dentry, | |
201 | .fh_to_parent = btrfs_fh_to_parent, | |
202 | .get_parent = btrfs_get_parent, | |
203 | }; |