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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
16static int btrfs_encode_fh(struct inode *inode, u32 *fh, int *max_len,
17 struct inode *parent)
18{
19 struct btrfs_fid *fid = (struct btrfs_fid *)fh;
20 int len = *max_len;
21 int type;
22
23 if (parent && (len < BTRFS_FID_SIZE_CONNECTABLE)) {
24 *max_len = BTRFS_FID_SIZE_CONNECTABLE;
25 return 255;
26 } else if (len < BTRFS_FID_SIZE_NON_CONNECTABLE) {
27 *max_len = BTRFS_FID_SIZE_NON_CONNECTABLE;
28 return 255;
29 }
30
31 len = BTRFS_FID_SIZE_NON_CONNECTABLE;
32 type = FILEID_BTRFS_WITHOUT_PARENT;
33
34 fid->objectid = btrfs_ino(inode);
35 fid->root_objectid = BTRFS_I(inode)->root->objectid;
36 fid->gen = inode->i_generation;
37
38 if (parent) {
39 u64 parent_root_id;
40
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
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
59static struct dentry *btrfs_get_dentry(struct super_block *sb, u64 objectid,
60 u64 root_objectid, u32 generation,
61 int check_generation)
62{
63 struct btrfs_fs_info *fs_info = btrfs_sb(sb);
64 struct btrfs_root *root;
65 struct inode *inode;
66 struct btrfs_key key;
67 int index;
68 int err = 0;
69
70 if (objectid < BTRFS_FIRST_FREE_OBJECTID)
71 return ERR_PTR(-ESTALE);
72
73 key.objectid = root_objectid;
74 btrfs_set_key_type(&key, BTRFS_ROOT_ITEM_KEY);
75 key.offset = (u64)-1;
76
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
85 if (btrfs_root_refs(&root->root_item) == 0) {
86 err = -ENOENT;
87 goto fail;
88 }
89
90 key.objectid = objectid;
91 btrfs_set_key_type(&key, BTRFS_INODE_ITEM_KEY);
92 key.offset = 0;
93
94 inode = btrfs_iget(sb, &key, root, NULL);
95 if (IS_ERR(inode)) {
96 err = PTR_ERR(inode);
97 goto fail;
98 }
99
100 srcu_read_unlock(&fs_info->subvol_srcu, index);
101
102 if (check_generation && generation != inode->i_generation) {
103 iput(inode);
104 return ERR_PTR(-ESTALE);
105 }
106
107 return d_obtain_alias(inode);
108fail:
109 srcu_read_unlock(&fs_info->subvol_srcu, index);
110 return ERR_PTR(err);
111}
112
113static struct dentry *btrfs_fh_to_parent(struct super_block *sb, struct fid *fh,
114 int fh_len, int fh_type)
115{
116 struct btrfs_fid *fid = (struct btrfs_fid *) fh;
117 u64 objectid, root_objectid;
118 u32 generation;
119
120 if (fh_type == FILEID_BTRFS_WITH_PARENT) {
121 if (fh_len != BTRFS_FID_SIZE_CONNECTABLE)
122 return NULL;
123 root_objectid = fid->root_objectid;
124 } else if (fh_type == FILEID_BTRFS_WITH_PARENT_ROOT) {
125 if (fh_len != BTRFS_FID_SIZE_CONNECTABLE_ROOT)
126 return NULL;
127 root_objectid = fid->parent_root_objectid;
128 } else
129 return NULL;
130
131 objectid = fid->parent_objectid;
132 generation = fid->parent_gen;
133
134 return btrfs_get_dentry(sb, objectid, root_objectid, generation, 1);
135}
136
137static struct dentry *btrfs_fh_to_dentry(struct super_block *sb, struct fid *fh,
138 int fh_len, int fh_type)
139{
140 struct btrfs_fid *fid = (struct btrfs_fid *) fh;
141 u64 objectid, root_objectid;
142 u32 generation;
143
144 if ((fh_type != FILEID_BTRFS_WITH_PARENT ||
145 fh_len != BTRFS_FID_SIZE_CONNECTABLE) &&
146 (fh_type != FILEID_BTRFS_WITH_PARENT_ROOT ||
147 fh_len != BTRFS_FID_SIZE_CONNECTABLE_ROOT) &&
148 (fh_type != FILEID_BTRFS_WITHOUT_PARENT ||
149 fh_len != BTRFS_FID_SIZE_NON_CONNECTABLE))
150 return NULL;
151
152 objectid = fid->objectid;
153 root_objectid = fid->root_objectid;
154 generation = fid->gen;
155
156 return btrfs_get_dentry(sb, objectid, root_objectid, generation, 1);
157}
158
159static struct dentry *btrfs_get_parent(struct dentry *child)
160{
161 struct inode *dir = child->d_inode;
162 struct btrfs_root *root = BTRFS_I(dir)->root;
163 struct btrfs_path *path;
164 struct extent_buffer *leaf;
165 struct btrfs_root_ref *ref;
166 struct btrfs_key key;
167 struct btrfs_key found_key;
168 int ret;
169
170 path = btrfs_alloc_path();
171 if (!path)
172 return ERR_PTR(-ENOMEM);
173
174 if (btrfs_ino(dir) == BTRFS_FIRST_FREE_OBJECTID) {
175 key.objectid = root->root_key.objectid;
176 key.type = BTRFS_ROOT_BACKREF_KEY;
177 key.offset = (u64)-1;
178 root = root->fs_info->tree_root;
179 } else {
180 key.objectid = btrfs_ino(dir);
181 key.type = BTRFS_INODE_REF_KEY;
182 key.offset = (u64)-1;
183 }
184
185 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
186 if (ret < 0)
187 goto fail;
188
189 BUG_ON(ret == 0); /* Key with offset of -1 found */
190 if (path->slots[0] == 0) {
191 ret = -ENOENT;
192 goto fail;
193 }
194
195 path->slots[0]--;
196 leaf = path->nodes[0];
197
198 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
199 if (found_key.objectid != key.objectid || found_key.type != key.type) {
200 ret = -ENOENT;
201 goto fail;
202 }
203
204 if (found_key.type == BTRFS_ROOT_BACKREF_KEY) {
205 ref = btrfs_item_ptr(leaf, path->slots[0],
206 struct btrfs_root_ref);
207 key.objectid = btrfs_root_ref_dirid(leaf, ref);
208 } else {
209 key.objectid = found_key.offset;
210 }
211 btrfs_free_path(path);
212
213 if (found_key.type == BTRFS_ROOT_BACKREF_KEY) {
214 return btrfs_get_dentry(root->fs_info->sb, key.objectid,
215 found_key.offset, 0, 0);
216 }
217
218 key.type = BTRFS_INODE_ITEM_KEY;
219 key.offset = 0;
220 return d_obtain_alias(btrfs_iget(root->fs_info->sb, &key, root, NULL));
221fail:
222 btrfs_free_path(path);
223 return ERR_PTR(ret);
224}
225
226static int btrfs_get_name(struct dentry *parent, char *name,
227 struct dentry *child)
228{
229 struct inode *inode = child->d_inode;
230 struct inode *dir = parent->d_inode;
231 struct btrfs_path *path;
232 struct btrfs_root *root = BTRFS_I(dir)->root;
233 struct btrfs_inode_ref *iref;
234 struct btrfs_root_ref *rref;
235 struct extent_buffer *leaf;
236 unsigned long name_ptr;
237 struct btrfs_key key;
238 int name_len;
239 int ret;
240 u64 ino;
241
242 if (!dir || !inode)
243 return -EINVAL;
244
245 if (!S_ISDIR(dir->i_mode))
246 return -EINVAL;
247
248 ino = btrfs_ino(inode);
249
250 path = btrfs_alloc_path();
251 if (!path)
252 return -ENOMEM;
253 path->leave_spinning = 1;
254
255 if (ino == BTRFS_FIRST_FREE_OBJECTID) {
256 key.objectid = BTRFS_I(inode)->root->root_key.objectid;
257 key.type = BTRFS_ROOT_BACKREF_KEY;
258 key.offset = (u64)-1;
259 root = root->fs_info->tree_root;
260 } else {
261 key.objectid = ino;
262 key.offset = btrfs_ino(dir);
263 key.type = BTRFS_INODE_REF_KEY;
264 }
265
266 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
267 if (ret < 0) {
268 btrfs_free_path(path);
269 return ret;
270 } else if (ret > 0) {
271 if (ino == BTRFS_FIRST_FREE_OBJECTID) {
272 path->slots[0]--;
273 } else {
274 btrfs_free_path(path);
275 return -ENOENT;
276 }
277 }
278 leaf = path->nodes[0];
279
280 if (ino == BTRFS_FIRST_FREE_OBJECTID) {
281 rref = btrfs_item_ptr(leaf, path->slots[0],
282 struct btrfs_root_ref);
283 name_ptr = (unsigned long)(rref + 1);
284 name_len = btrfs_root_ref_name_len(leaf, rref);
285 } else {
286 iref = btrfs_item_ptr(leaf, path->slots[0],
287 struct btrfs_inode_ref);
288 name_ptr = (unsigned long)(iref + 1);
289 name_len = btrfs_inode_ref_name_len(leaf, iref);
290 }
291
292 read_extent_buffer(leaf, name, name_ptr, name_len);
293 btrfs_free_path(path);
294
295 /*
296 * have to add the null termination to make sure that reconnect_path
297 * gets the right len for strlen
298 */
299 name[name_len] = '\0';
300
301 return 0;
302}
303
304const struct export_operations btrfs_export_ops = {
305 .encode_fh = btrfs_encode_fh,
306 .fh_to_dentry = btrfs_fh_to_dentry,
307 .fh_to_parent = btrfs_fh_to_parent,
308 .get_parent = btrfs_get_parent,
309 .get_name = btrfs_get_name,
310};
1// SPDX-License-Identifier: GPL-2.0
2
3#include <linux/fs.h>
4#include <linux/types.h>
5#include "ctree.h"
6#include "disk-io.h"
7#include "btrfs_inode.h"
8#include "print-tree.h"
9#include "export.h"
10
11#define BTRFS_FID_SIZE_NON_CONNECTABLE (offsetof(struct btrfs_fid, \
12 parent_objectid) / 4)
13#define BTRFS_FID_SIZE_CONNECTABLE (offsetof(struct btrfs_fid, \
14 parent_root_objectid) / 4)
15#define BTRFS_FID_SIZE_CONNECTABLE_ROOT (sizeof(struct btrfs_fid) / 4)
16
17static int btrfs_encode_fh(struct inode *inode, u32 *fh, int *max_len,
18 struct inode *parent)
19{
20 struct btrfs_fid *fid = (struct btrfs_fid *)fh;
21 int len = *max_len;
22 int type;
23
24 if (parent && (len < BTRFS_FID_SIZE_CONNECTABLE)) {
25 *max_len = BTRFS_FID_SIZE_CONNECTABLE;
26 return FILEID_INVALID;
27 } else if (len < BTRFS_FID_SIZE_NON_CONNECTABLE) {
28 *max_len = BTRFS_FID_SIZE_NON_CONNECTABLE;
29 return FILEID_INVALID;
30 }
31
32 len = BTRFS_FID_SIZE_NON_CONNECTABLE;
33 type = FILEID_BTRFS_WITHOUT_PARENT;
34
35 fid->objectid = btrfs_ino(BTRFS_I(inode));
36 fid->root_objectid = BTRFS_I(inode)->root->root_key.objectid;
37 fid->gen = inode->i_generation;
38
39 if (parent) {
40 u64 parent_root_id;
41
42 fid->parent_objectid = BTRFS_I(parent)->location.objectid;
43 fid->parent_gen = parent->i_generation;
44 parent_root_id = BTRFS_I(parent)->root->root_key.objectid;
45
46 if (parent_root_id != fid->root_objectid) {
47 fid->parent_root_objectid = parent_root_id;
48 len = BTRFS_FID_SIZE_CONNECTABLE_ROOT;
49 type = FILEID_BTRFS_WITH_PARENT_ROOT;
50 } else {
51 len = BTRFS_FID_SIZE_CONNECTABLE;
52 type = FILEID_BTRFS_WITH_PARENT;
53 }
54 }
55
56 *max_len = len;
57 return type;
58}
59
60struct dentry *btrfs_get_dentry(struct super_block *sb, u64 objectid,
61 u64 root_objectid, u32 generation,
62 int check_generation)
63{
64 struct btrfs_fs_info *fs_info = btrfs_sb(sb);
65 struct btrfs_root *root;
66 struct inode *inode;
67
68 if (objectid < BTRFS_FIRST_FREE_OBJECTID)
69 return ERR_PTR(-ESTALE);
70
71 root = btrfs_get_fs_root(fs_info, root_objectid, true);
72 if (IS_ERR(root))
73 return ERR_CAST(root);
74
75 inode = btrfs_iget(sb, objectid, root);
76 btrfs_put_root(root);
77 if (IS_ERR(inode))
78 return ERR_CAST(inode);
79
80 if (check_generation && generation != inode->i_generation) {
81 iput(inode);
82 return ERR_PTR(-ESTALE);
83 }
84
85 return d_obtain_alias(inode);
86}
87
88static struct dentry *btrfs_fh_to_parent(struct super_block *sb, struct fid *fh,
89 int fh_len, int fh_type)
90{
91 struct btrfs_fid *fid = (struct btrfs_fid *) fh;
92 u64 objectid, root_objectid;
93 u32 generation;
94
95 if (fh_type == FILEID_BTRFS_WITH_PARENT) {
96 if (fh_len < BTRFS_FID_SIZE_CONNECTABLE)
97 return NULL;
98 root_objectid = fid->root_objectid;
99 } else if (fh_type == FILEID_BTRFS_WITH_PARENT_ROOT) {
100 if (fh_len < BTRFS_FID_SIZE_CONNECTABLE_ROOT)
101 return NULL;
102 root_objectid = fid->parent_root_objectid;
103 } else
104 return NULL;
105
106 objectid = fid->parent_objectid;
107 generation = fid->parent_gen;
108
109 return btrfs_get_dentry(sb, objectid, root_objectid, generation, 1);
110}
111
112static struct dentry *btrfs_fh_to_dentry(struct super_block *sb, struct fid *fh,
113 int fh_len, int fh_type)
114{
115 struct btrfs_fid *fid = (struct btrfs_fid *) fh;
116 u64 objectid, root_objectid;
117 u32 generation;
118
119 if ((fh_type != FILEID_BTRFS_WITH_PARENT ||
120 fh_len < BTRFS_FID_SIZE_CONNECTABLE) &&
121 (fh_type != FILEID_BTRFS_WITH_PARENT_ROOT ||
122 fh_len < BTRFS_FID_SIZE_CONNECTABLE_ROOT) &&
123 (fh_type != FILEID_BTRFS_WITHOUT_PARENT ||
124 fh_len < BTRFS_FID_SIZE_NON_CONNECTABLE))
125 return NULL;
126
127 objectid = fid->objectid;
128 root_objectid = fid->root_objectid;
129 generation = fid->gen;
130
131 return btrfs_get_dentry(sb, objectid, root_objectid, generation, 1);
132}
133
134struct dentry *btrfs_get_parent(struct dentry *child)
135{
136 struct inode *dir = d_inode(child);
137 struct btrfs_fs_info *fs_info = btrfs_sb(dir->i_sb);
138 struct btrfs_root *root = BTRFS_I(dir)->root;
139 struct btrfs_path *path;
140 struct extent_buffer *leaf;
141 struct btrfs_root_ref *ref;
142 struct btrfs_key key;
143 struct btrfs_key found_key;
144 int ret;
145
146 path = btrfs_alloc_path();
147 if (!path)
148 return ERR_PTR(-ENOMEM);
149
150 if (btrfs_ino(BTRFS_I(dir)) == BTRFS_FIRST_FREE_OBJECTID) {
151 key.objectid = root->root_key.objectid;
152 key.type = BTRFS_ROOT_BACKREF_KEY;
153 key.offset = (u64)-1;
154 root = fs_info->tree_root;
155 } else {
156 key.objectid = btrfs_ino(BTRFS_I(dir));
157 key.type = BTRFS_INODE_REF_KEY;
158 key.offset = (u64)-1;
159 }
160
161 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
162 if (ret < 0)
163 goto fail;
164
165 BUG_ON(ret == 0); /* Key with offset of -1 found */
166 if (path->slots[0] == 0) {
167 ret = -ENOENT;
168 goto fail;
169 }
170
171 path->slots[0]--;
172 leaf = path->nodes[0];
173
174 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
175 if (found_key.objectid != key.objectid || found_key.type != key.type) {
176 ret = -ENOENT;
177 goto fail;
178 }
179
180 if (found_key.type == BTRFS_ROOT_BACKREF_KEY) {
181 ref = btrfs_item_ptr(leaf, path->slots[0],
182 struct btrfs_root_ref);
183 key.objectid = btrfs_root_ref_dirid(leaf, ref);
184 } else {
185 key.objectid = found_key.offset;
186 }
187 btrfs_free_path(path);
188
189 if (found_key.type == BTRFS_ROOT_BACKREF_KEY) {
190 return btrfs_get_dentry(fs_info->sb, key.objectid,
191 found_key.offset, 0, 0);
192 }
193
194 return d_obtain_alias(btrfs_iget(fs_info->sb, key.objectid, root));
195fail:
196 btrfs_free_path(path);
197 return ERR_PTR(ret);
198}
199
200static int btrfs_get_name(struct dentry *parent, char *name,
201 struct dentry *child)
202{
203 struct inode *inode = d_inode(child);
204 struct inode *dir = d_inode(parent);
205 struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
206 struct btrfs_path *path;
207 struct btrfs_root *root = BTRFS_I(dir)->root;
208 struct btrfs_inode_ref *iref;
209 struct btrfs_root_ref *rref;
210 struct extent_buffer *leaf;
211 unsigned long name_ptr;
212 struct btrfs_key key;
213 int name_len;
214 int ret;
215 u64 ino;
216
217 if (!S_ISDIR(dir->i_mode))
218 return -EINVAL;
219
220 ino = btrfs_ino(BTRFS_I(inode));
221
222 path = btrfs_alloc_path();
223 if (!path)
224 return -ENOMEM;
225 path->leave_spinning = 1;
226
227 if (ino == BTRFS_FIRST_FREE_OBJECTID) {
228 key.objectid = BTRFS_I(inode)->root->root_key.objectid;
229 key.type = BTRFS_ROOT_BACKREF_KEY;
230 key.offset = (u64)-1;
231 root = fs_info->tree_root;
232 } else {
233 key.objectid = ino;
234 key.offset = btrfs_ino(BTRFS_I(dir));
235 key.type = BTRFS_INODE_REF_KEY;
236 }
237
238 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
239 if (ret < 0) {
240 btrfs_free_path(path);
241 return ret;
242 } else if (ret > 0) {
243 if (ino == BTRFS_FIRST_FREE_OBJECTID) {
244 path->slots[0]--;
245 } else {
246 btrfs_free_path(path);
247 return -ENOENT;
248 }
249 }
250 leaf = path->nodes[0];
251
252 if (ino == BTRFS_FIRST_FREE_OBJECTID) {
253 rref = btrfs_item_ptr(leaf, path->slots[0],
254 struct btrfs_root_ref);
255 name_ptr = (unsigned long)(rref + 1);
256 name_len = btrfs_root_ref_name_len(leaf, rref);
257 } else {
258 iref = btrfs_item_ptr(leaf, path->slots[0],
259 struct btrfs_inode_ref);
260 name_ptr = (unsigned long)(iref + 1);
261 name_len = btrfs_inode_ref_name_len(leaf, iref);
262 }
263
264 read_extent_buffer(leaf, name, name_ptr, name_len);
265 btrfs_free_path(path);
266
267 /*
268 * have to add the null termination to make sure that reconnect_path
269 * gets the right len for strlen
270 */
271 name[name_len] = '\0';
272
273 return 0;
274}
275
276const struct export_operations btrfs_export_ops = {
277 .encode_fh = btrfs_encode_fh,
278 .fh_to_dentry = btrfs_fh_to_dentry,
279 .fh_to_parent = btrfs_fh_to_parent,
280 .get_parent = btrfs_get_parent,
281 .get_name = btrfs_get_name,
282};