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 dentry *dentry, u32 *fh, int *max_len,
17 int connectable)
18{
19 struct btrfs_fid *fid = (struct btrfs_fid *)fh;
20 struct inode *inode = dentry->d_inode;
21 int len = *max_len;
22 int type;
23
24 if (connectable && (len < BTRFS_FID_SIZE_CONNECTABLE)) {
25 *max_len = BTRFS_FID_SIZE_CONNECTABLE;
26 return 255;
27 } else if (len < BTRFS_FID_SIZE_NON_CONNECTABLE) {
28 *max_len = BTRFS_FID_SIZE_NON_CONNECTABLE;
29 return 255;
30 }
31
32 len = BTRFS_FID_SIZE_NON_CONNECTABLE;
33 type = FILEID_BTRFS_WITHOUT_PARENT;
34
35 fid->objectid = btrfs_ino(inode);
36 fid->root_objectid = BTRFS_I(inode)->root->objectid;
37 fid->gen = inode->i_generation;
38
39 if (connectable && !S_ISDIR(inode->i_mode)) {
40 struct inode *parent;
41 u64 parent_root_id;
42
43 spin_lock(&dentry->d_lock);
44
45 parent = dentry->d_parent->d_inode;
46 fid->parent_objectid = BTRFS_I(parent)->location.objectid;
47 fid->parent_gen = parent->i_generation;
48 parent_root_id = BTRFS_I(parent)->root->objectid;
49
50 spin_unlock(&dentry->d_lock);
51
52 if (parent_root_id != fid->root_objectid) {
53 fid->parent_root_objectid = parent_root_id;
54 len = BTRFS_FID_SIZE_CONNECTABLE_ROOT;
55 type = FILEID_BTRFS_WITH_PARENT_ROOT;
56 } else {
57 len = BTRFS_FID_SIZE_CONNECTABLE;
58 type = FILEID_BTRFS_WITH_PARENT;
59 }
60 }
61
62 *max_len = len;
63 return type;
64}
65
66static struct dentry *btrfs_get_dentry(struct super_block *sb, u64 objectid,
67 u64 root_objectid, u32 generation,
68 int check_generation)
69{
70 struct btrfs_fs_info *fs_info = btrfs_sb(sb)->fs_info;
71 struct btrfs_root *root;
72 struct inode *inode;
73 struct btrfs_key key;
74 int index;
75 int err = 0;
76
77 if (objectid < BTRFS_FIRST_FREE_OBJECTID)
78 return ERR_PTR(-ESTALE);
79
80 key.objectid = root_objectid;
81 btrfs_set_key_type(&key, BTRFS_ROOT_ITEM_KEY);
82 key.offset = (u64)-1;
83
84 index = srcu_read_lock(&fs_info->subvol_srcu);
85
86 root = btrfs_read_fs_root_no_name(fs_info, &key);
87 if (IS_ERR(root)) {
88 err = PTR_ERR(root);
89 goto fail;
90 }
91
92 if (btrfs_root_refs(&root->root_item) == 0) {
93 err = -ENOENT;
94 goto fail;
95 }
96
97 key.objectid = objectid;
98 btrfs_set_key_type(&key, BTRFS_INODE_ITEM_KEY);
99 key.offset = 0;
100
101 inode = btrfs_iget(sb, &key, root, NULL);
102 if (IS_ERR(inode)) {
103 err = PTR_ERR(inode);
104 goto fail;
105 }
106
107 srcu_read_unlock(&fs_info->subvol_srcu, index);
108
109 if (check_generation && generation != inode->i_generation) {
110 iput(inode);
111 return ERR_PTR(-ESTALE);
112 }
113
114 return d_obtain_alias(inode);
115fail:
116 srcu_read_unlock(&fs_info->subvol_srcu, index);
117 return ERR_PTR(err);
118}
119
120static struct dentry *btrfs_fh_to_parent(struct super_block *sb, struct fid *fh,
121 int fh_len, int fh_type)
122{
123 struct btrfs_fid *fid = (struct btrfs_fid *) fh;
124 u64 objectid, root_objectid;
125 u32 generation;
126
127 if (fh_type == FILEID_BTRFS_WITH_PARENT) {
128 if (fh_len != BTRFS_FID_SIZE_CONNECTABLE)
129 return NULL;
130 root_objectid = fid->root_objectid;
131 } else if (fh_type == FILEID_BTRFS_WITH_PARENT_ROOT) {
132 if (fh_len != BTRFS_FID_SIZE_CONNECTABLE_ROOT)
133 return NULL;
134 root_objectid = fid->parent_root_objectid;
135 } else
136 return NULL;
137
138 objectid = fid->parent_objectid;
139 generation = fid->parent_gen;
140
141 return btrfs_get_dentry(sb, objectid, root_objectid, generation, 1);
142}
143
144static struct dentry *btrfs_fh_to_dentry(struct super_block *sb, struct fid *fh,
145 int fh_len, int fh_type)
146{
147 struct btrfs_fid *fid = (struct btrfs_fid *) fh;
148 u64 objectid, root_objectid;
149 u32 generation;
150
151 if ((fh_type != FILEID_BTRFS_WITH_PARENT ||
152 fh_len != BTRFS_FID_SIZE_CONNECTABLE) &&
153 (fh_type != FILEID_BTRFS_WITH_PARENT_ROOT ||
154 fh_len != BTRFS_FID_SIZE_CONNECTABLE_ROOT) &&
155 (fh_type != FILEID_BTRFS_WITHOUT_PARENT ||
156 fh_len != BTRFS_FID_SIZE_NON_CONNECTABLE))
157 return NULL;
158
159 objectid = fid->objectid;
160 root_objectid = fid->root_objectid;
161 generation = fid->gen;
162
163 return btrfs_get_dentry(sb, objectid, root_objectid, generation, 1);
164}
165
166static struct dentry *btrfs_get_parent(struct dentry *child)
167{
168 struct inode *dir = child->d_inode;
169 struct btrfs_root *root = BTRFS_I(dir)->root;
170 struct btrfs_path *path;
171 struct extent_buffer *leaf;
172 struct btrfs_root_ref *ref;
173 struct btrfs_key key;
174 struct btrfs_key found_key;
175 int ret;
176
177 path = btrfs_alloc_path();
178 if (!path)
179 return ERR_PTR(-ENOMEM);
180
181 if (btrfs_ino(dir) == BTRFS_FIRST_FREE_OBJECTID) {
182 key.objectid = root->root_key.objectid;
183 key.type = BTRFS_ROOT_BACKREF_KEY;
184 key.offset = (u64)-1;
185 root = root->fs_info->tree_root;
186 } else {
187 key.objectid = btrfs_ino(dir);
188 key.type = BTRFS_INODE_REF_KEY;
189 key.offset = (u64)-1;
190 }
191
192 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
193 if (ret < 0)
194 goto fail;
195
196 BUG_ON(ret == 0);
197 if (path->slots[0] == 0) {
198 ret = -ENOENT;
199 goto fail;
200 }
201
202 path->slots[0]--;
203 leaf = path->nodes[0];
204
205 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
206 if (found_key.objectid != key.objectid || found_key.type != key.type) {
207 ret = -ENOENT;
208 goto fail;
209 }
210
211 if (found_key.type == BTRFS_ROOT_BACKREF_KEY) {
212 ref = btrfs_item_ptr(leaf, path->slots[0],
213 struct btrfs_root_ref);
214 key.objectid = btrfs_root_ref_dirid(leaf, ref);
215 } else {
216 key.objectid = found_key.offset;
217 }
218 btrfs_free_path(path);
219
220 if (found_key.type == BTRFS_ROOT_BACKREF_KEY) {
221 return btrfs_get_dentry(root->fs_info->sb, key.objectid,
222 found_key.offset, 0, 0);
223 }
224
225 key.type = BTRFS_INODE_ITEM_KEY;
226 key.offset = 0;
227 return d_obtain_alias(btrfs_iget(root->fs_info->sb, &key, root, NULL));
228fail:
229 btrfs_free_path(path);
230 return ERR_PTR(ret);
231}
232
233static int btrfs_get_name(struct dentry *parent, char *name,
234 struct dentry *child)
235{
236 struct inode *inode = child->d_inode;
237 struct inode *dir = parent->d_inode;
238 struct btrfs_path *path;
239 struct btrfs_root *root = BTRFS_I(dir)->root;
240 struct btrfs_inode_ref *iref;
241 struct btrfs_root_ref *rref;
242 struct extent_buffer *leaf;
243 unsigned long name_ptr;
244 struct btrfs_key key;
245 int name_len;
246 int ret;
247 u64 ino;
248
249 if (!dir || !inode)
250 return -EINVAL;
251
252 if (!S_ISDIR(dir->i_mode))
253 return -EINVAL;
254
255 ino = btrfs_ino(inode);
256
257 path = btrfs_alloc_path();
258 if (!path)
259 return -ENOMEM;
260 path->leave_spinning = 1;
261
262 if (ino == BTRFS_FIRST_FREE_OBJECTID) {
263 key.objectid = BTRFS_I(inode)->root->root_key.objectid;
264 key.type = BTRFS_ROOT_BACKREF_KEY;
265 key.offset = (u64)-1;
266 root = root->fs_info->tree_root;
267 } else {
268 key.objectid = ino;
269 key.offset = btrfs_ino(dir);
270 key.type = BTRFS_INODE_REF_KEY;
271 }
272
273 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
274 if (ret < 0) {
275 btrfs_free_path(path);
276 return ret;
277 } else if (ret > 0) {
278 if (ino == BTRFS_FIRST_FREE_OBJECTID) {
279 path->slots[0]--;
280 } else {
281 btrfs_free_path(path);
282 return -ENOENT;
283 }
284 }
285 leaf = path->nodes[0];
286
287 if (ino == BTRFS_FIRST_FREE_OBJECTID) {
288 rref = btrfs_item_ptr(leaf, path->slots[0],
289 struct btrfs_root_ref);
290 name_ptr = (unsigned long)(rref + 1);
291 name_len = btrfs_root_ref_name_len(leaf, rref);
292 } else {
293 iref = btrfs_item_ptr(leaf, path->slots[0],
294 struct btrfs_inode_ref);
295 name_ptr = (unsigned long)(iref + 1);
296 name_len = btrfs_inode_ref_name_len(leaf, iref);
297 }
298
299 read_extent_buffer(leaf, name, name_ptr, name_len);
300 btrfs_free_path(path);
301
302
303
304
305
306 name[name_len] = '\0';
307
308 return 0;
309}
310
311const struct export_operations btrfs_export_ops = {
312 .encode_fh = btrfs_encode_fh,
313 .fh_to_dentry = btrfs_fh_to_dentry,
314 .fh_to_parent = btrfs_fh_to_parent,
315 .get_parent = btrfs_get_parent,
316 .get_name = btrfs_get_name,
317};
318
