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b2441318 | 1 | // SPDX-License-Identifier: GPL-2.0 |
be6e8dc0 BR |
2 | #include <linux/fs.h> |
3 | #include <linux/types.h> | |
4 | #include "ctree.h" | |
5 | #include "disk-io.h" | |
6 | #include "btrfs_inode.h" | |
7 | #include "print-tree.h" | |
8 | #include "export.h" | |
be6e8dc0 | 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 | 15 | |
b0b0382b AV |
16 | static int btrfs_encode_fh(struct inode *inode, u32 *fh, int *max_len, |
17 | struct inode *parent) | |
be6e8dc0 BR |
18 | { |
19 | struct btrfs_fid *fid = (struct btrfs_fid *)fh; | |
be6e8dc0 BR |
20 | int len = *max_len; |
21 | int type; | |
22 | ||
b0b0382b | 23 | if (parent && (len < BTRFS_FID_SIZE_CONNECTABLE)) { |
5fe0c237 | 24 | *max_len = BTRFS_FID_SIZE_CONNECTABLE; |
94e07a75 | 25 | return FILEID_INVALID; |
5fe0c237 AK |
26 | } else if (len < BTRFS_FID_SIZE_NON_CONNECTABLE) { |
27 | *max_len = BTRFS_FID_SIZE_NON_CONNECTABLE; | |
94e07a75 | 28 | return FILEID_INVALID; |
5fe0c237 | 29 | } |
be6e8dc0 BR |
30 | |
31 | len = BTRFS_FID_SIZE_NON_CONNECTABLE; | |
32 | type = FILEID_BTRFS_WITHOUT_PARENT; | |
33 | ||
4a0cc7ca | 34 | fid->objectid = btrfs_ino(BTRFS_I(inode)); |
be6e8dc0 BR |
35 | fid->root_objectid = BTRFS_I(inode)->root->objectid; |
36 | fid->gen = inode->i_generation; | |
37 | ||
b0b0382b | 38 | if (parent) { |
be6e8dc0 BR |
39 | u64 parent_root_id; |
40 | ||
be6e8dc0 BR |
41 | fid->parent_objectid = BTRFS_I(parent)->location.objectid; |
42 | fid->parent_gen = parent->i_generation; | |
43 | parent_root_id = BTRFS_I(parent)->root->objectid; | |
44 | ||
be6e8dc0 BR |
45 | if (parent_root_id != fid->root_objectid) { |
46 | fid->parent_root_objectid = parent_root_id; | |
47 | len = BTRFS_FID_SIZE_CONNECTABLE_ROOT; | |
48 | type = FILEID_BTRFS_WITH_PARENT_ROOT; | |
49 | } else { | |
50 | len = BTRFS_FID_SIZE_CONNECTABLE; | |
51 | type = FILEID_BTRFS_WITH_PARENT; | |
52 | } | |
53 | } | |
54 | ||
55 | *max_len = len; | |
56 | return type; | |
57 | } | |
58 | ||
59 | static struct dentry *btrfs_get_dentry(struct super_block *sb, u64 objectid, | |
76dda93c YZ |
60 | u64 root_objectid, u32 generation, |
61 | int check_generation) | |
be6e8dc0 | 62 | { |
815745cf | 63 | struct btrfs_fs_info *fs_info = btrfs_sb(sb); |
be6e8dc0 BR |
64 | struct btrfs_root *root; |
65 | struct inode *inode; | |
be6e8dc0 | 66 | struct btrfs_key key; |
76dda93c YZ |
67 | int index; |
68 | int err = 0; | |
69 | ||
70 | if (objectid < BTRFS_FIRST_FREE_OBJECTID) | |
71 | return ERR_PTR(-ESTALE); | |
be6e8dc0 | 72 | |
2d4d9fbd | 73 | key.objectid = root_objectid; |
962a298f | 74 | key.type = BTRFS_ROOT_ITEM_KEY; |
2d4d9fbd DW |
75 | key.offset = (u64)-1; |
76 | ||
76dda93c YZ |
77 | index = srcu_read_lock(&fs_info->subvol_srcu); |
78 | ||
79 | root = btrfs_read_fs_root_no_name(fs_info, &key); | |
80 | if (IS_ERR(root)) { | |
81 | err = PTR_ERR(root); | |
82 | goto fail; | |
83 | } | |
84 | ||
be6e8dc0 | 85 | key.objectid = objectid; |
962a298f | 86 | key.type = BTRFS_INODE_ITEM_KEY; |
be6e8dc0 BR |
87 | key.offset = 0; |
88 | ||
73f73415 | 89 | inode = btrfs_iget(sb, &key, root, NULL); |
76dda93c YZ |
90 | if (IS_ERR(inode)) { |
91 | err = PTR_ERR(inode); | |
92 | goto fail; | |
93 | } | |
94 | ||
95 | srcu_read_unlock(&fs_info->subvol_srcu, index); | |
be6e8dc0 | 96 | |
76dda93c | 97 | if (check_generation && generation != inode->i_generation) { |
be6e8dc0 BR |
98 | iput(inode); |
99 | return ERR_PTR(-ESTALE); | |
100 | } | |
101 | ||
af53d29a | 102 | return d_obtain_alias(inode); |
76dda93c YZ |
103 | fail: |
104 | srcu_read_unlock(&fs_info->subvol_srcu, index); | |
105 | return ERR_PTR(err); | |
be6e8dc0 BR |
106 | } |
107 | ||
108 | static struct dentry *btrfs_fh_to_parent(struct super_block *sb, struct fid *fh, | |
109 | int fh_len, int fh_type) | |
110 | { | |
111 | struct btrfs_fid *fid = (struct btrfs_fid *) fh; | |
112 | u64 objectid, root_objectid; | |
113 | u32 generation; | |
114 | ||
115 | if (fh_type == FILEID_BTRFS_WITH_PARENT) { | |
7d35199e | 116 | if (fh_len < BTRFS_FID_SIZE_CONNECTABLE) |
be6e8dc0 BR |
117 | return NULL; |
118 | root_objectid = fid->root_objectid; | |
119 | } else if (fh_type == FILEID_BTRFS_WITH_PARENT_ROOT) { | |
7d35199e | 120 | if (fh_len < BTRFS_FID_SIZE_CONNECTABLE_ROOT) |
be6e8dc0 BR |
121 | return NULL; |
122 | root_objectid = fid->parent_root_objectid; | |
123 | } else | |
124 | return NULL; | |
125 | ||
126 | objectid = fid->parent_objectid; | |
127 | generation = fid->parent_gen; | |
128 | ||
76dda93c | 129 | return btrfs_get_dentry(sb, objectid, root_objectid, generation, 1); |
be6e8dc0 BR |
130 | } |
131 | ||
132 | static struct dentry *btrfs_fh_to_dentry(struct super_block *sb, struct fid *fh, | |
133 | int fh_len, int fh_type) | |
134 | { | |
135 | struct btrfs_fid *fid = (struct btrfs_fid *) fh; | |
136 | u64 objectid, root_objectid; | |
137 | u32 generation; | |
138 | ||
139 | if ((fh_type != FILEID_BTRFS_WITH_PARENT || | |
7d35199e | 140 | fh_len < BTRFS_FID_SIZE_CONNECTABLE) && |
be6e8dc0 | 141 | (fh_type != FILEID_BTRFS_WITH_PARENT_ROOT || |
7d35199e | 142 | fh_len < BTRFS_FID_SIZE_CONNECTABLE_ROOT) && |
be6e8dc0 | 143 | (fh_type != FILEID_BTRFS_WITHOUT_PARENT || |
7d35199e | 144 | fh_len < BTRFS_FID_SIZE_NON_CONNECTABLE)) |
be6e8dc0 BR |
145 | return NULL; |
146 | ||
147 | objectid = fid->objectid; | |
148 | root_objectid = fid->root_objectid; | |
149 | generation = fid->gen; | |
150 | ||
76dda93c | 151 | return btrfs_get_dentry(sb, objectid, root_objectid, generation, 1); |
be6e8dc0 BR |
152 | } |
153 | ||
154 | static struct dentry *btrfs_get_parent(struct dentry *child) | |
155 | { | |
2b0143b5 | 156 | struct inode *dir = d_inode(child); |
0b246afa | 157 | struct btrfs_fs_info *fs_info = btrfs_sb(dir->i_sb); |
be6e8dc0 | 158 | struct btrfs_root *root = BTRFS_I(dir)->root; |
be6e8dc0 BR |
159 | struct btrfs_path *path; |
160 | struct extent_buffer *leaf; | |
76dda93c YZ |
161 | struct btrfs_root_ref *ref; |
162 | struct btrfs_key key; | |
163 | struct btrfs_key found_key; | |
be6e8dc0 BR |
164 | int ret; |
165 | ||
166 | path = btrfs_alloc_path(); | |
2a29edc6 | 167 | if (!path) |
168 | return ERR_PTR(-ENOMEM); | |
be6e8dc0 | 169 | |
4a0cc7ca | 170 | if (btrfs_ino(BTRFS_I(dir)) == BTRFS_FIRST_FREE_OBJECTID) { |
76dda93c YZ |
171 | key.objectid = root->root_key.objectid; |
172 | key.type = BTRFS_ROOT_BACKREF_KEY; | |
173 | key.offset = (u64)-1; | |
0b246afa | 174 | root = fs_info->tree_root; |
76dda93c | 175 | } else { |
4a0cc7ca | 176 | key.objectid = btrfs_ino(BTRFS_I(dir)); |
76dda93c YZ |
177 | key.type = BTRFS_INODE_REF_KEY; |
178 | key.offset = (u64)-1; | |
179 | } | |
be6e8dc0 | 180 | |
87acb4ef | 181 | ret = btrfs_search_slot(NULL, root, &key, path, 0, 0); |
76dda93c YZ |
182 | if (ret < 0) |
183 | goto fail; | |
184 | ||
79787eaa | 185 | BUG_ON(ret == 0); /* Key with offset of -1 found */ |
76dda93c YZ |
186 | if (path->slots[0] == 0) { |
187 | ret = -ENOENT; | |
188 | goto fail; | |
d54a8390 | 189 | } |
76dda93c YZ |
190 | |
191 | path->slots[0]--; | |
be6e8dc0 | 192 | leaf = path->nodes[0]; |
76dda93c YZ |
193 | |
194 | btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]); | |
195 | if (found_key.objectid != key.objectid || found_key.type != key.type) { | |
196 | ret = -ENOENT; | |
197 | goto fail; | |
be6e8dc0 BR |
198 | } |
199 | ||
76dda93c YZ |
200 | if (found_key.type == BTRFS_ROOT_BACKREF_KEY) { |
201 | ref = btrfs_item_ptr(leaf, path->slots[0], | |
202 | struct btrfs_root_ref); | |
203 | key.objectid = btrfs_root_ref_dirid(leaf, ref); | |
204 | } else { | |
205 | key.objectid = found_key.offset; | |
206 | } | |
be6e8dc0 BR |
207 | btrfs_free_path(path); |
208 | ||
76dda93c | 209 | if (found_key.type == BTRFS_ROOT_BACKREF_KEY) { |
0b246afa | 210 | return btrfs_get_dentry(fs_info->sb, key.objectid, |
76dda93c YZ |
211 | found_key.offset, 0, 0); |
212 | } | |
2d4d9fbd | 213 | |
76dda93c | 214 | key.type = BTRFS_INODE_ITEM_KEY; |
be6e8dc0 | 215 | key.offset = 0; |
0b246afa | 216 | return d_obtain_alias(btrfs_iget(fs_info->sb, &key, root, NULL)); |
76dda93c YZ |
217 | fail: |
218 | btrfs_free_path(path); | |
219 | return ERR_PTR(ret); | |
be6e8dc0 BR |
220 | } |
221 | ||
2ede0daf JB |
222 | static int btrfs_get_name(struct dentry *parent, char *name, |
223 | struct dentry *child) | |
224 | { | |
2b0143b5 DH |
225 | struct inode *inode = d_inode(child); |
226 | struct inode *dir = d_inode(parent); | |
0b246afa | 227 | struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb); |
2ede0daf JB |
228 | struct btrfs_path *path; |
229 | struct btrfs_root *root = BTRFS_I(dir)->root; | |
230 | struct btrfs_inode_ref *iref; | |
231 | struct btrfs_root_ref *rref; | |
232 | struct extent_buffer *leaf; | |
233 | unsigned long name_ptr; | |
234 | struct btrfs_key key; | |
235 | int name_len; | |
236 | int ret; | |
33345d01 | 237 | u64 ino; |
2ede0daf | 238 | |
2ede0daf JB |
239 | if (!S_ISDIR(dir->i_mode)) |
240 | return -EINVAL; | |
241 | ||
4a0cc7ca | 242 | ino = btrfs_ino(BTRFS_I(inode)); |
33345d01 | 243 | |
2ede0daf JB |
244 | path = btrfs_alloc_path(); |
245 | if (!path) | |
246 | return -ENOMEM; | |
247 | path->leave_spinning = 1; | |
248 | ||
33345d01 | 249 | if (ino == BTRFS_FIRST_FREE_OBJECTID) { |
2ede0daf JB |
250 | key.objectid = BTRFS_I(inode)->root->root_key.objectid; |
251 | key.type = BTRFS_ROOT_BACKREF_KEY; | |
252 | key.offset = (u64)-1; | |
0b246afa | 253 | root = fs_info->tree_root; |
2ede0daf | 254 | } else { |
33345d01 | 255 | key.objectid = ino; |
4a0cc7ca | 256 | key.offset = btrfs_ino(BTRFS_I(dir)); |
2ede0daf JB |
257 | key.type = BTRFS_INODE_REF_KEY; |
258 | } | |
259 | ||
260 | ret = btrfs_search_slot(NULL, root, &key, path, 0, 0); | |
261 | if (ret < 0) { | |
262 | btrfs_free_path(path); | |
263 | return ret; | |
264 | } else if (ret > 0) { | |
33345d01 | 265 | if (ino == BTRFS_FIRST_FREE_OBJECTID) { |
2ede0daf JB |
266 | path->slots[0]--; |
267 | } else { | |
268 | btrfs_free_path(path); | |
269 | return -ENOENT; | |
270 | } | |
271 | } | |
272 | leaf = path->nodes[0]; | |
273 | ||
33345d01 LZ |
274 | if (ino == BTRFS_FIRST_FREE_OBJECTID) { |
275 | rref = btrfs_item_ptr(leaf, path->slots[0], | |
2ede0daf | 276 | struct btrfs_root_ref); |
33345d01 LZ |
277 | name_ptr = (unsigned long)(rref + 1); |
278 | name_len = btrfs_root_ref_name_len(leaf, rref); | |
2ede0daf JB |
279 | } else { |
280 | iref = btrfs_item_ptr(leaf, path->slots[0], | |
281 | struct btrfs_inode_ref); | |
282 | name_ptr = (unsigned long)(iref + 1); | |
283 | name_len = btrfs_inode_ref_name_len(leaf, iref); | |
284 | } | |
285 | ||
286 | read_extent_buffer(leaf, name, name_ptr, name_len); | |
287 | btrfs_free_path(path); | |
288 | ||
289 | /* | |
290 | * have to add the null termination to make sure that reconnect_path | |
291 | * gets the right len for strlen | |
292 | */ | |
293 | name[name_len] = '\0'; | |
294 | ||
295 | return 0; | |
296 | } | |
297 | ||
be6e8dc0 BR |
298 | const struct export_operations btrfs_export_ops = { |
299 | .encode_fh = btrfs_encode_fh, | |
300 | .fh_to_dentry = btrfs_fh_to_dentry, | |
301 | .fh_to_parent = btrfs_fh_to_parent, | |
302 | .get_parent = btrfs_get_parent, | |
2ede0daf | 303 | .get_name = btrfs_get_name, |
be6e8dc0 | 304 | }; |