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 key.objectid = objectid;
86 btrfs_set_key_type(&key, BTRFS_INODE_ITEM_KEY);
87 key.offset = 0;
88
89 inode = btrfs_iget(sb, &key, root, NULL);
90 if (IS_ERR(inode)) {
91 err = PTR_ERR(inode);
92 goto fail;
93 }
94
95 srcu_read_unlock(&fs_info->subvol_srcu, index);
96
97 if (check_generation && generation != inode->i_generation) {
98 iput(inode);
99 return ERR_PTR(-ESTALE);
100 }
101
102 return d_obtain_alias(inode);
103fail:
104 srcu_read_unlock(&fs_info->subvol_srcu, index);
105 return ERR_PTR(err);
106}
107
108static struct dentry *btrfs_fh_to_parent(struct super_block *sb, struct fid *fh,
109 int fh_len, int fh_type)
110{
111 struct btrfs_fid *fid = (struct btrfs_fid *) fh;
112 u64 objectid, root_objectid;
113 u32 generation;
114
115 if (fh_type == FILEID_BTRFS_WITH_PARENT) {
116 if (fh_len != BTRFS_FID_SIZE_CONNECTABLE)
117 return NULL;
118 root_objectid = fid->root_objectid;
119 } else if (fh_type == FILEID_BTRFS_WITH_PARENT_ROOT) {
120 if (fh_len != BTRFS_FID_SIZE_CONNECTABLE_ROOT)
121 return NULL;
122 root_objectid = fid->parent_root_objectid;
123 } else
124 return NULL;
125
126 objectid = fid->parent_objectid;
127 generation = fid->parent_gen;
128
129 return btrfs_get_dentry(sb, objectid, root_objectid, generation, 1);
130}
131
132static struct dentry *btrfs_fh_to_dentry(struct super_block *sb, struct fid *fh,
133 int fh_len, int fh_type)
134{
135 struct btrfs_fid *fid = (struct btrfs_fid *) fh;
136 u64 objectid, root_objectid;
137 u32 generation;
138
139 if ((fh_type != FILEID_BTRFS_WITH_PARENT ||
140 fh_len != BTRFS_FID_SIZE_CONNECTABLE) &&
141 (fh_type != FILEID_BTRFS_WITH_PARENT_ROOT ||
142 fh_len != BTRFS_FID_SIZE_CONNECTABLE_ROOT) &&
143 (fh_type != FILEID_BTRFS_WITHOUT_PARENT ||
144 fh_len != BTRFS_FID_SIZE_NON_CONNECTABLE))
145 return NULL;
146
147 objectid = fid->objectid;
148 root_objectid = fid->root_objectid;
149 generation = fid->gen;
150
151 return btrfs_get_dentry(sb, objectid, root_objectid, generation, 1);
152}
153
154static struct dentry *btrfs_get_parent(struct dentry *child)
155{
156 struct inode *dir = child->d_inode;
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 = 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);
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(root->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(root->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 = child->d_inode;
225 struct inode *dir = parent->d_inode;
226 struct btrfs_path *path;
227 struct btrfs_root *root = BTRFS_I(dir)->root;
228 struct btrfs_inode_ref *iref;
229 struct btrfs_root_ref *rref;
230 struct extent_buffer *leaf;
231 unsigned long name_ptr;
232 struct btrfs_key key;
233 int name_len;
234 int ret;
235 u64 ino;
236
237 if (!dir || !inode)
238 return -EINVAL;
239
240 if (!S_ISDIR(dir->i_mode))
241 return -EINVAL;
242
243 ino = btrfs_ino(inode);
244
245 path = btrfs_alloc_path();
246 if (!path)
247 return -ENOMEM;
248 path->leave_spinning = 1;
249
250 if (ino == BTRFS_FIRST_FREE_OBJECTID) {
251 key.objectid = BTRFS_I(inode)->root->root_key.objectid;
252 key.type = BTRFS_ROOT_BACKREF_KEY;
253 key.offset = (u64)-1;
254 root = root->fs_info->tree_root;
255 } else {
256 key.objectid = ino;
257 key.offset = btrfs_ino(dir);
258 key.type = BTRFS_INODE_REF_KEY;
259 }
260
261 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
262 if (ret < 0) {
263 btrfs_free_path(path);
264 return ret;
265 } else if (ret > 0) {
266 if (ino == BTRFS_FIRST_FREE_OBJECTID) {
267 path->slots[0]--;
268 } else {
269 btrfs_free_path(path);
270 return -ENOENT;
271 }
272 }
273 leaf = path->nodes[0];
274
275 if (ino == BTRFS_FIRST_FREE_OBJECTID) {
276 rref = btrfs_item_ptr(leaf, path->slots[0],
277 struct btrfs_root_ref);
278 name_ptr = (unsigned long)(rref + 1);
279 name_len = btrfs_root_ref_name_len(leaf, rref);
280 } else {
281 iref = btrfs_item_ptr(leaf, path->slots[0],
282 struct btrfs_inode_ref);
283 name_ptr = (unsigned long)(iref + 1);
284 name_len = btrfs_inode_ref_name_len(leaf, iref);
285 }
286
287 read_extent_buffer(leaf, name, name_ptr, name_len);
288 btrfs_free_path(path);
289
290
291
292
293
294 name[name_len] = '\0';
295
296 return 0;
297}
298
299const struct export_operations btrfs_export_ops = {
300 .encode_fh = btrfs_encode_fh,
301 .fh_to_dentry = btrfs_fh_to_dentry,
302 .fh_to_parent = btrfs_fh_to_parent,
303 .get_parent = btrfs_get_parent,
304 .get_name = btrfs_get_name,
305};
306
