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 FILEID_INVALID;
26 } else if (len < BTRFS_FID_SIZE_NON_CONNECTABLE) {
27 *max_len = BTRFS_FID_SIZE_NON_CONNECTABLE;
28 return FILEID_INVALID;
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);
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
297
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};
311
