Loading...
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// 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 "export.h"
9#include "accessors.h"
10#include "super.h"
11
12#define BTRFS_FID_SIZE_NON_CONNECTABLE (offsetof(struct btrfs_fid, \
13 parent_objectid) / 4)
14#define BTRFS_FID_SIZE_CONNECTABLE (offsetof(struct btrfs_fid, \
15 parent_root_objectid) / 4)
16#define BTRFS_FID_SIZE_CONNECTABLE_ROOT (sizeof(struct btrfs_fid) / 4)
17
18static int btrfs_encode_fh(struct inode *inode, u32 *fh, int *max_len,
19 struct inode *parent)
20{
21 struct btrfs_fid *fid = (struct btrfs_fid *)fh;
22 int len = *max_len;
23 int type;
24
25 if (parent && (len < BTRFS_FID_SIZE_CONNECTABLE)) {
26 *max_len = BTRFS_FID_SIZE_CONNECTABLE;
27 return FILEID_INVALID;
28 } else if (len < BTRFS_FID_SIZE_NON_CONNECTABLE) {
29 *max_len = BTRFS_FID_SIZE_NON_CONNECTABLE;
30 return FILEID_INVALID;
31 }
32
33 len = BTRFS_FID_SIZE_NON_CONNECTABLE;
34 type = FILEID_BTRFS_WITHOUT_PARENT;
35
36 fid->objectid = btrfs_ino(BTRFS_I(inode));
37 fid->root_objectid = btrfs_root_id(BTRFS_I(inode)->root);
38 fid->gen = inode->i_generation;
39
40 if (parent) {
41 u64 parent_root_id;
42
43 fid->parent_objectid = btrfs_ino(BTRFS_I(parent));
44 fid->parent_gen = parent->i_generation;
45 parent_root_id = btrfs_root_id(BTRFS_I(parent)->root);
46
47 if (parent_root_id != fid->root_objectid) {
48 fid->parent_root_objectid = parent_root_id;
49 len = BTRFS_FID_SIZE_CONNECTABLE_ROOT;
50 type = FILEID_BTRFS_WITH_PARENT_ROOT;
51 } else {
52 len = BTRFS_FID_SIZE_CONNECTABLE;
53 type = FILEID_BTRFS_WITH_PARENT;
54 }
55 }
56
57 *max_len = len;
58 return type;
59}
60
61/*
62 * Read dentry of inode with @objectid from filesystem root @root_objectid.
63 *
64 * @sb: the filesystem super block
65 * @objectid: inode objectid
66 * @root_objectid: object id of the subvolume root where to look up the inode
67 * @generation: optional, if not zero, verify that the found inode
68 * generation matches
69 *
70 * Return dentry alias for the inode, otherwise an error. In case the
71 * generation does not match return ESTALE.
72 */
73struct dentry *btrfs_get_dentry(struct super_block *sb, u64 objectid,
74 u64 root_objectid, u64 generation)
75{
76 struct btrfs_fs_info *fs_info = btrfs_sb(sb);
77 struct btrfs_root *root;
78 struct inode *inode;
79
80 if (objectid < BTRFS_FIRST_FREE_OBJECTID)
81 return ERR_PTR(-ESTALE);
82
83 root = btrfs_get_fs_root(fs_info, root_objectid, true);
84 if (IS_ERR(root))
85 return ERR_CAST(root);
86
87 inode = btrfs_iget(objectid, root);
88 btrfs_put_root(root);
89 if (IS_ERR(inode))
90 return ERR_CAST(inode);
91
92 if (generation != 0 && generation != inode->i_generation) {
93 iput(inode);
94 return ERR_PTR(-ESTALE);
95 }
96
97 return d_obtain_alias(inode);
98}
99
100static struct dentry *btrfs_fh_to_parent(struct super_block *sb, struct fid *fh,
101 int fh_len, int fh_type)
102{
103 struct btrfs_fid *fid = (struct btrfs_fid *) fh;
104 u64 objectid, root_objectid;
105 u32 generation;
106
107 if (fh_type == FILEID_BTRFS_WITH_PARENT) {
108 if (fh_len < BTRFS_FID_SIZE_CONNECTABLE)
109 return NULL;
110 root_objectid = fid->root_objectid;
111 } else if (fh_type == FILEID_BTRFS_WITH_PARENT_ROOT) {
112 if (fh_len < BTRFS_FID_SIZE_CONNECTABLE_ROOT)
113 return NULL;
114 root_objectid = fid->parent_root_objectid;
115 } else
116 return NULL;
117
118 objectid = fid->parent_objectid;
119 generation = fid->parent_gen;
120
121 return btrfs_get_dentry(sb, objectid, root_objectid, generation);
122}
123
124static struct dentry *btrfs_fh_to_dentry(struct super_block *sb, struct fid *fh,
125 int fh_len, int fh_type)
126{
127 struct btrfs_fid *fid = (struct btrfs_fid *) fh;
128 u64 objectid, root_objectid;
129 u32 generation;
130
131 if ((fh_type != FILEID_BTRFS_WITH_PARENT ||
132 fh_len < BTRFS_FID_SIZE_CONNECTABLE) &&
133 (fh_type != FILEID_BTRFS_WITH_PARENT_ROOT ||
134 fh_len < BTRFS_FID_SIZE_CONNECTABLE_ROOT) &&
135 (fh_type != FILEID_BTRFS_WITHOUT_PARENT ||
136 fh_len < BTRFS_FID_SIZE_NON_CONNECTABLE))
137 return NULL;
138
139 objectid = fid->objectid;
140 root_objectid = fid->root_objectid;
141 generation = fid->gen;
142
143 return btrfs_get_dentry(sb, objectid, root_objectid, generation);
144}
145
146struct dentry *btrfs_get_parent(struct dentry *child)
147{
148 struct inode *dir = d_inode(child);
149 struct btrfs_fs_info *fs_info = btrfs_sb(dir->i_sb);
150 struct btrfs_root *root = BTRFS_I(dir)->root;
151 struct btrfs_path *path;
152 struct extent_buffer *leaf;
153 struct btrfs_root_ref *ref;
154 struct btrfs_key key;
155 struct btrfs_key found_key;
156 int ret;
157
158 path = btrfs_alloc_path();
159 if (!path)
160 return ERR_PTR(-ENOMEM);
161
162 if (btrfs_ino(BTRFS_I(dir)) == BTRFS_FIRST_FREE_OBJECTID) {
163 key.objectid = btrfs_root_id(root);
164 key.type = BTRFS_ROOT_BACKREF_KEY;
165 key.offset = (u64)-1;
166 root = fs_info->tree_root;
167 } else {
168 key.objectid = btrfs_ino(BTRFS_I(dir));
169 key.type = BTRFS_INODE_REF_KEY;
170 key.offset = (u64)-1;
171 }
172
173 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
174 if (ret < 0)
175 goto fail;
176 if (ret == 0) {
177 /*
178 * Key with offset of -1 found, there would have to exist an
179 * inode with such number or a root with such id.
180 */
181 ret = -EUCLEAN;
182 goto fail;
183 }
184
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);
211 }
212
213 return d_obtain_alias(btrfs_iget(key.objectid, root));
214fail:
215 btrfs_free_path(path);
216 return ERR_PTR(ret);
217}
218
219static int btrfs_get_name(struct dentry *parent, char *name,
220 struct dentry *child)
221{
222 struct inode *inode = d_inode(child);
223 struct inode *dir = d_inode(parent);
224 struct btrfs_fs_info *fs_info = inode_to_fs_info(inode);
225 struct btrfs_path *path;
226 struct btrfs_root *root = BTRFS_I(dir)->root;
227 struct btrfs_inode_ref *iref;
228 struct btrfs_root_ref *rref;
229 struct extent_buffer *leaf;
230 unsigned long name_ptr;
231 struct btrfs_key key;
232 int name_len;
233 int ret;
234 u64 ino;
235
236 if (!S_ISDIR(dir->i_mode))
237 return -EINVAL;
238
239 ino = btrfs_ino(BTRFS_I(inode));
240
241 path = btrfs_alloc_path();
242 if (!path)
243 return -ENOMEM;
244
245 if (ino == BTRFS_FIRST_FREE_OBJECTID) {
246 key.objectid = btrfs_root_id(BTRFS_I(inode)->root);
247 key.type = BTRFS_ROOT_BACKREF_KEY;
248 key.offset = (u64)-1;
249 root = fs_info->tree_root;
250 } else {
251 key.objectid = ino;
252 key.offset = btrfs_ino(BTRFS_I(dir));
253 key.type = BTRFS_INODE_REF_KEY;
254 }
255
256 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
257 if (ret < 0) {
258 btrfs_free_path(path);
259 return ret;
260 } else if (ret > 0) {
261 if (ino == BTRFS_FIRST_FREE_OBJECTID) {
262 path->slots[0]--;
263 } else {
264 btrfs_free_path(path);
265 return -ENOENT;
266 }
267 }
268 leaf = path->nodes[0];
269
270 if (ino == BTRFS_FIRST_FREE_OBJECTID) {
271 rref = btrfs_item_ptr(leaf, path->slots[0],
272 struct btrfs_root_ref);
273 name_ptr = (unsigned long)(rref + 1);
274 name_len = btrfs_root_ref_name_len(leaf, rref);
275 } else {
276 iref = btrfs_item_ptr(leaf, path->slots[0],
277 struct btrfs_inode_ref);
278 name_ptr = (unsigned long)(iref + 1);
279 name_len = btrfs_inode_ref_name_len(leaf, iref);
280 }
281
282 read_extent_buffer(leaf, name, name_ptr, name_len);
283 btrfs_free_path(path);
284
285 /*
286 * have to add the null termination to make sure that reconnect_path
287 * gets the right len for strlen
288 */
289 name[name_len] = '\0';
290
291 return 0;
292}
293
294const struct export_operations btrfs_export_ops = {
295 .encode_fh = btrfs_encode_fh,
296 .fh_to_dentry = btrfs_fh_to_dentry,
297 .fh_to_parent = btrfs_fh_to_parent,
298 .get_parent = btrfs_get_parent,
299 .get_name = btrfs_get_name,
300};