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
9#define BTRFS_FID_SIZE_NON_CONNECTABLE (offsetof(struct btrfs_fid, \
10 parent_objectid) / 4)
11#define BTRFS_FID_SIZE_CONNECTABLE (offsetof(struct btrfs_fid, \
12 parent_root_objectid) / 4)
13#define BTRFS_FID_SIZE_CONNECTABLE_ROOT (sizeof(struct btrfs_fid) / 4)
14
15static int btrfs_encode_fh(struct inode *inode, u32 *fh, int *max_len,
16 struct inode *parent)
17{
18 struct btrfs_fid *fid = (struct btrfs_fid *)fh;
19 int len = *max_len;
20 int type;
21
22 if (parent && (len < BTRFS_FID_SIZE_CONNECTABLE)) {
23 *max_len = BTRFS_FID_SIZE_CONNECTABLE;
24 return FILEID_INVALID;
25 } else if (len < BTRFS_FID_SIZE_NON_CONNECTABLE) {
26 *max_len = BTRFS_FID_SIZE_NON_CONNECTABLE;
27 return FILEID_INVALID;
28 }
29
30 len = BTRFS_FID_SIZE_NON_CONNECTABLE;
31 type = FILEID_BTRFS_WITHOUT_PARENT;
32
33 fid->objectid = btrfs_ino(inode);
34 fid->root_objectid = BTRFS_I(inode)->root->objectid;
35 fid->gen = inode->i_generation;
36
37 if (parent) {
38 u64 parent_root_id;
39
40 fid->parent_objectid = BTRFS_I(parent)->location.objectid;
41 fid->parent_gen = parent->i_generation;
42 parent_root_id = BTRFS_I(parent)->root->objectid;
43
44 if (parent_root_id != fid->root_objectid) {
45 fid->parent_root_objectid = parent_root_id;
46 len = BTRFS_FID_SIZE_CONNECTABLE_ROOT;
47 type = FILEID_BTRFS_WITH_PARENT_ROOT;
48 } else {
49 len = BTRFS_FID_SIZE_CONNECTABLE;
50 type = FILEID_BTRFS_WITH_PARENT;
51 }
52 }
53
54 *max_len = len;
55 return type;
56}
57
58static struct dentry *btrfs_get_dentry(struct super_block *sb, u64 objectid,
59 u64 root_objectid, u32 generation,
60 int check_generation)
61{
62 struct btrfs_fs_info *fs_info = btrfs_sb(sb);
63 struct btrfs_root *root;
64 struct inode *inode;
65 struct btrfs_key key;
66 int index;
67 int err = 0;
68
69 if (objectid < BTRFS_FIRST_FREE_OBJECTID)
70 return ERR_PTR(-ESTALE);
71
72 key.objectid = root_objectid;
73 key.type = BTRFS_ROOT_ITEM_KEY;
74 key.offset = (u64)-1;
75
76 index = srcu_read_lock(&fs_info->subvol_srcu);
77
78 root = btrfs_read_fs_root_no_name(fs_info, &key);
79 if (IS_ERR(root)) {
80 err = PTR_ERR(root);
81 goto fail;
82 }
83
84 key.objectid = objectid;
85 key.type = BTRFS_INODE_ITEM_KEY;
86 key.offset = 0;
87
88 inode = btrfs_iget(sb, &key, root, NULL);
89 if (IS_ERR(inode)) {
90 err = PTR_ERR(inode);
91 goto fail;
92 }
93
94 srcu_read_unlock(&fs_info->subvol_srcu, index);
95
96 if (check_generation && generation != inode->i_generation) {
97 iput(inode);
98 return ERR_PTR(-ESTALE);
99 }
100
101 return d_obtain_alias(inode);
102fail:
103 srcu_read_unlock(&fs_info->subvol_srcu, index);
104 return ERR_PTR(err);
105}
106
107static struct dentry *btrfs_fh_to_parent(struct super_block *sb, struct fid *fh,
108 int fh_len, int fh_type)
109{
110 struct btrfs_fid *fid = (struct btrfs_fid *) fh;
111 u64 objectid, root_objectid;
112 u32 generation;
113
114 if (fh_type == FILEID_BTRFS_WITH_PARENT) {
115 if (fh_len < BTRFS_FID_SIZE_CONNECTABLE)
116 return NULL;
117 root_objectid = fid->root_objectid;
118 } else if (fh_type == FILEID_BTRFS_WITH_PARENT_ROOT) {
119 if (fh_len < BTRFS_FID_SIZE_CONNECTABLE_ROOT)
120 return NULL;
121 root_objectid = fid->parent_root_objectid;
122 } else
123 return NULL;
124
125 objectid = fid->parent_objectid;
126 generation = fid->parent_gen;
127
128 return btrfs_get_dentry(sb, objectid, root_objectid, generation, 1);
129}
130
131static struct dentry *btrfs_fh_to_dentry(struct super_block *sb, struct fid *fh,
132 int fh_len, int fh_type)
133{
134 struct btrfs_fid *fid = (struct btrfs_fid *) fh;
135 u64 objectid, root_objectid;
136 u32 generation;
137
138 if ((fh_type != FILEID_BTRFS_WITH_PARENT ||
139 fh_len < BTRFS_FID_SIZE_CONNECTABLE) &&
140 (fh_type != FILEID_BTRFS_WITH_PARENT_ROOT ||
141 fh_len < BTRFS_FID_SIZE_CONNECTABLE_ROOT) &&
142 (fh_type != FILEID_BTRFS_WITHOUT_PARENT ||
143 fh_len < BTRFS_FID_SIZE_NON_CONNECTABLE))
144 return NULL;
145
146 objectid = fid->objectid;
147 root_objectid = fid->root_objectid;
148 generation = fid->gen;
149
150 return btrfs_get_dentry(sb, objectid, root_objectid, generation, 1);
151}
152
153static struct dentry *btrfs_get_parent(struct dentry *child)
154{
155 struct inode *dir = d_inode(child);
156 struct btrfs_root *root = BTRFS_I(dir)->root;
157 struct btrfs_path *path;
158 struct extent_buffer *leaf;
159 struct btrfs_root_ref *ref;
160 struct btrfs_key key;
161 struct btrfs_key found_key;
162 int ret;
163
164 path = btrfs_alloc_path();
165 if (!path)
166 return ERR_PTR(-ENOMEM);
167
168 if (btrfs_ino(dir) == BTRFS_FIRST_FREE_OBJECTID) {
169 key.objectid = root->root_key.objectid;
170 key.type = BTRFS_ROOT_BACKREF_KEY;
171 key.offset = (u64)-1;
172 root = root->fs_info->tree_root;
173 } else {
174 key.objectid = btrfs_ino(dir);
175 key.type = BTRFS_INODE_REF_KEY;
176 key.offset = (u64)-1;
177 }
178
179 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
180 if (ret < 0)
181 goto fail;
182
183 BUG_ON(ret == 0);
184 if (path->slots[0] == 0) {
185 ret = -ENOENT;
186 goto fail;
187 }
188
189 path->slots[0]--;
190 leaf = path->nodes[0];
191
192 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
193 if (found_key.objectid != key.objectid || found_key.type != key.type) {
194 ret = -ENOENT;
195 goto fail;
196 }
197
198 if (found_key.type == BTRFS_ROOT_BACKREF_KEY) {
199 ref = btrfs_item_ptr(leaf, path->slots[0],
200 struct btrfs_root_ref);
201 key.objectid = btrfs_root_ref_dirid(leaf, ref);
202 } else {
203 key.objectid = found_key.offset;
204 }
205 btrfs_free_path(path);
206
207 if (found_key.type == BTRFS_ROOT_BACKREF_KEY) {
208 return btrfs_get_dentry(root->fs_info->sb, key.objectid,
209 found_key.offset, 0, 0);
210 }
211
212 key.type = BTRFS_INODE_ITEM_KEY;
213 key.offset = 0;
214 return d_obtain_alias(btrfs_iget(root->fs_info->sb, &key, root, NULL));
215fail:
216 btrfs_free_path(path);
217 return ERR_PTR(ret);
218}
219
220static int btrfs_get_name(struct dentry *parent, char *name,
221 struct dentry *child)
222{
223 struct inode *inode = d_inode(child);
224 struct inode *dir = d_inode(parent);
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 (!dir || !inode)
237 return -EINVAL;
238
239 if (!S_ISDIR(dir->i_mode))
240 return -EINVAL;
241
242 ino = btrfs_ino(inode);
243
244 path = btrfs_alloc_path();
245 if (!path)
246 return -ENOMEM;
247 path->leave_spinning = 1;
248
249 if (ino == BTRFS_FIRST_FREE_OBJECTID) {
250 key.objectid = BTRFS_I(inode)->root->root_key.objectid;
251 key.type = BTRFS_ROOT_BACKREF_KEY;
252 key.offset = (u64)-1;
253 root = root->fs_info->tree_root;
254 } else {
255 key.objectid = ino;
256 key.offset = btrfs_ino(dir);
257 key.type = BTRFS_INODE_REF_KEY;
258 }
259
260 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
261 if (ret < 0) {
262 btrfs_free_path(path);
263 return ret;
264 } else if (ret > 0) {
265 if (ino == BTRFS_FIRST_FREE_OBJECTID) {
266 path->slots[0]--;
267 } else {
268 btrfs_free_path(path);
269 return -ENOENT;
270 }
271 }
272 leaf = path->nodes[0];
273
274 if (ino == BTRFS_FIRST_FREE_OBJECTID) {
275 rref = btrfs_item_ptr(leaf, path->slots[0],
276 struct btrfs_root_ref);
277 name_ptr = (unsigned long)(rref + 1);
278 name_len = btrfs_root_ref_name_len(leaf, rref);
279 } else {
280 iref = btrfs_item_ptr(leaf, path->slots[0],
281 struct btrfs_inode_ref);
282 name_ptr = (unsigned long)(iref + 1);
283 name_len = btrfs_inode_ref_name_len(leaf, iref);
284 }
285
286 read_extent_buffer(leaf, name, name_ptr, name_len);
287 btrfs_free_path(path);
288
289
290
291
292
293 name[name_len] = '\0';
294
295 return 0;
296}
297
298const struct export_operations btrfs_export_ops = {
299 .encode_fh = btrfs_encode_fh,
300 .fh_to_dentry = btrfs_fh_to_dentry,
301 .fh_to_parent = btrfs_fh_to_parent,
302 .get_parent = btrfs_get_parent,
303 .get_name = btrfs_get_name,
304};
305
