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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#include "accessors.h"
11#include "super.h"
12
13#define BTRFS_FID_SIZE_NON_CONNECTABLE (offsetof(struct btrfs_fid, \
14 parent_objectid) / 4)
15#define BTRFS_FID_SIZE_CONNECTABLE (offsetof(struct btrfs_fid, \
16 parent_root_objectid) / 4)
17#define BTRFS_FID_SIZE_CONNECTABLE_ROOT (sizeof(struct btrfs_fid) / 4)
18
19static int btrfs_encode_fh(struct inode *inode, u32 *fh, int *max_len,
20 struct inode *parent)
21{
22 struct btrfs_fid *fid = (struct btrfs_fid *)fh;
23 int len = *max_len;
24 int type;
25
26 if (parent && (len < BTRFS_FID_SIZE_CONNECTABLE)) {
27 *max_len = BTRFS_FID_SIZE_CONNECTABLE;
28 return FILEID_INVALID;
29 } else if (len < BTRFS_FID_SIZE_NON_CONNECTABLE) {
30 *max_len = BTRFS_FID_SIZE_NON_CONNECTABLE;
31 return FILEID_INVALID;
32 }
33
34 len = BTRFS_FID_SIZE_NON_CONNECTABLE;
35 type = FILEID_BTRFS_WITHOUT_PARENT;
36
37 fid->objectid = btrfs_ino(BTRFS_I(inode));
38 fid->root_objectid = BTRFS_I(inode)->root->root_key.objectid;
39 fid->gen = inode->i_generation;
40
41 if (parent) {
42 u64 parent_root_id;
43
44 fid->parent_objectid = BTRFS_I(parent)->location.objectid;
45 fid->parent_gen = parent->i_generation;
46 parent_root_id = BTRFS_I(parent)->root->root_key.objectid;
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/*
63 * Read dentry of inode with @objectid from filesystem root @root_objectid.
64 *
65 * @sb: the filesystem super block
66 * @objectid: inode objectid
67 * @root_objectid: object id of the subvolume root where to look up the inode
68 * @generation: optional, if not zero, verify that the found inode
69 * generation matches
70 *
71 * Return dentry alias for the inode, otherwise an error. In case the
72 * generation does not match return ESTALE.
73 */
74struct dentry *btrfs_get_dentry(struct super_block *sb, u64 objectid,
75 u64 root_objectid, u64 generation)
76{
77 struct btrfs_fs_info *fs_info = btrfs_sb(sb);
78 struct btrfs_root *root;
79 struct inode *inode;
80
81 if (objectid < BTRFS_FIRST_FREE_OBJECTID)
82 return ERR_PTR(-ESTALE);
83
84 root = btrfs_get_fs_root(fs_info, root_objectid, true);
85 if (IS_ERR(root))
86 return ERR_CAST(root);
87
88 inode = btrfs_iget(sb, objectid, root);
89 btrfs_put_root(root);
90 if (IS_ERR(inode))
91 return ERR_CAST(inode);
92
93 if (generation != 0 && generation != inode->i_generation) {
94 iput(inode);
95 return ERR_PTR(-ESTALE);
96 }
97
98 return d_obtain_alias(inode);
99}
100
101static struct dentry *btrfs_fh_to_parent(struct super_block *sb, struct fid *fh,
102 int fh_len, int fh_type)
103{
104 struct btrfs_fid *fid = (struct btrfs_fid *) fh;
105 u64 objectid, root_objectid;
106 u32 generation;
107
108 if (fh_type == FILEID_BTRFS_WITH_PARENT) {
109 if (fh_len < BTRFS_FID_SIZE_CONNECTABLE)
110 return NULL;
111 root_objectid = fid->root_objectid;
112 } else if (fh_type == FILEID_BTRFS_WITH_PARENT_ROOT) {
113 if (fh_len < BTRFS_FID_SIZE_CONNECTABLE_ROOT)
114 return NULL;
115 root_objectid = fid->parent_root_objectid;
116 } else
117 return NULL;
118
119 objectid = fid->parent_objectid;
120 generation = fid->parent_gen;
121
122 return btrfs_get_dentry(sb, objectid, root_objectid, generation);
123}
124
125static struct dentry *btrfs_fh_to_dentry(struct super_block *sb, struct fid *fh,
126 int fh_len, int fh_type)
127{
128 struct btrfs_fid *fid = (struct btrfs_fid *) fh;
129 u64 objectid, root_objectid;
130 u32 generation;
131
132 if ((fh_type != FILEID_BTRFS_WITH_PARENT ||
133 fh_len < BTRFS_FID_SIZE_CONNECTABLE) &&
134 (fh_type != FILEID_BTRFS_WITH_PARENT_ROOT ||
135 fh_len < BTRFS_FID_SIZE_CONNECTABLE_ROOT) &&
136 (fh_type != FILEID_BTRFS_WITHOUT_PARENT ||
137 fh_len < BTRFS_FID_SIZE_NON_CONNECTABLE))
138 return NULL;
139
140 objectid = fid->objectid;
141 root_objectid = fid->root_objectid;
142 generation = fid->gen;
143
144 return btrfs_get_dentry(sb, objectid, root_objectid, generation);
145}
146
147struct dentry *btrfs_get_parent(struct dentry *child)
148{
149 struct inode *dir = d_inode(child);
150 struct btrfs_fs_info *fs_info = btrfs_sb(dir->i_sb);
151 struct btrfs_root *root = BTRFS_I(dir)->root;
152 struct btrfs_path *path;
153 struct extent_buffer *leaf;
154 struct btrfs_root_ref *ref;
155 struct btrfs_key key;
156 struct btrfs_key found_key;
157 int ret;
158
159 path = btrfs_alloc_path();
160 if (!path)
161 return ERR_PTR(-ENOMEM);
162
163 if (btrfs_ino(BTRFS_I(dir)) == BTRFS_FIRST_FREE_OBJECTID) {
164 key.objectid = root->root_key.objectid;
165 key.type = BTRFS_ROOT_BACKREF_KEY;
166 key.offset = (u64)-1;
167 root = fs_info->tree_root;
168 } else {
169 key.objectid = btrfs_ino(BTRFS_I(dir));
170 key.type = BTRFS_INODE_REF_KEY;
171 key.offset = (u64)-1;
172 }
173
174 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
175 if (ret < 0)
176 goto fail;
177
178 BUG_ON(ret == 0); /* Key with offset of -1 found */
179 if (path->slots[0] == 0) {
180 ret = -ENOENT;
181 goto fail;
182 }
183
184 path->slots[0]--;
185 leaf = path->nodes[0];
186
187 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
188 if (found_key.objectid != key.objectid || found_key.type != key.type) {
189 ret = -ENOENT;
190 goto fail;
191 }
192
193 if (found_key.type == BTRFS_ROOT_BACKREF_KEY) {
194 ref = btrfs_item_ptr(leaf, path->slots[0],
195 struct btrfs_root_ref);
196 key.objectid = btrfs_root_ref_dirid(leaf, ref);
197 } else {
198 key.objectid = found_key.offset;
199 }
200 btrfs_free_path(path);
201
202 if (found_key.type == BTRFS_ROOT_BACKREF_KEY) {
203 return btrfs_get_dentry(fs_info->sb, key.objectid,
204 found_key.offset, 0);
205 }
206
207 return d_obtain_alias(btrfs_iget(fs_info->sb, key.objectid, root));
208fail:
209 btrfs_free_path(path);
210 return ERR_PTR(ret);
211}
212
213static int btrfs_get_name(struct dentry *parent, char *name,
214 struct dentry *child)
215{
216 struct inode *inode = d_inode(child);
217 struct inode *dir = d_inode(parent);
218 struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
219 struct btrfs_path *path;
220 struct btrfs_root *root = BTRFS_I(dir)->root;
221 struct btrfs_inode_ref *iref;
222 struct btrfs_root_ref *rref;
223 struct extent_buffer *leaf;
224 unsigned long name_ptr;
225 struct btrfs_key key;
226 int name_len;
227 int ret;
228 u64 ino;
229
230 if (!S_ISDIR(dir->i_mode))
231 return -EINVAL;
232
233 ino = btrfs_ino(BTRFS_I(inode));
234
235 path = btrfs_alloc_path();
236 if (!path)
237 return -ENOMEM;
238
239 if (ino == BTRFS_FIRST_FREE_OBJECTID) {
240 key.objectid = BTRFS_I(inode)->root->root_key.objectid;
241 key.type = BTRFS_ROOT_BACKREF_KEY;
242 key.offset = (u64)-1;
243 root = fs_info->tree_root;
244 } else {
245 key.objectid = ino;
246 key.offset = btrfs_ino(BTRFS_I(dir));
247 key.type = BTRFS_INODE_REF_KEY;
248 }
249
250 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
251 if (ret < 0) {
252 btrfs_free_path(path);
253 return ret;
254 } else if (ret > 0) {
255 if (ino == BTRFS_FIRST_FREE_OBJECTID) {
256 path->slots[0]--;
257 } else {
258 btrfs_free_path(path);
259 return -ENOENT;
260 }
261 }
262 leaf = path->nodes[0];
263
264 if (ino == BTRFS_FIRST_FREE_OBJECTID) {
265 rref = btrfs_item_ptr(leaf, path->slots[0],
266 struct btrfs_root_ref);
267 name_ptr = (unsigned long)(rref + 1);
268 name_len = btrfs_root_ref_name_len(leaf, rref);
269 } else {
270 iref = btrfs_item_ptr(leaf, path->slots[0],
271 struct btrfs_inode_ref);
272 name_ptr = (unsigned long)(iref + 1);
273 name_len = btrfs_inode_ref_name_len(leaf, iref);
274 }
275
276 read_extent_buffer(leaf, name, name_ptr, name_len);
277 btrfs_free_path(path);
278
279 /*
280 * have to add the null termination to make sure that reconnect_path
281 * gets the right len for strlen
282 */
283 name[name_len] = '\0';
284
285 return 0;
286}
287
288const struct export_operations btrfs_export_ops = {
289 .encode_fh = btrfs_encode_fh,
290 .fh_to_dentry = btrfs_fh_to_dentry,
291 .fh_to_parent = btrfs_fh_to_parent,
292 .get_parent = btrfs_get_parent,
293 .get_name = btrfs_get_name,
294};
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};