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