1
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
11#define BTRFS_FID_SIZE_NON_CONNECTABLE (offsetof(struct btrfs_fid, \
12 parent_objectid) / 4)
13#define BTRFS_FID_SIZE_CONNECTABLE (offsetof(struct btrfs_fid, \
14 parent_root_objectid) / 4)
15#define BTRFS_FID_SIZE_CONNECTABLE_ROOT (sizeof(struct btrfs_fid) / 4)
16
17static int btrfs_encode_fh(struct inode *inode, u32 *fh, int *max_len,
18 struct inode *parent)
19{
20 struct btrfs_fid *fid = (struct btrfs_fid *)fh;
21 int len = *max_len;
22 int type;
23
24 if (parent && (len < BTRFS_FID_SIZE_CONNECTABLE)) {
25 *max_len = BTRFS_FID_SIZE_CONNECTABLE;
26 return FILEID_INVALID;
27 } else if (len < BTRFS_FID_SIZE_NON_CONNECTABLE) {
28 *max_len = BTRFS_FID_SIZE_NON_CONNECTABLE;
29 return FILEID_INVALID;
30 }
31
32 len = BTRFS_FID_SIZE_NON_CONNECTABLE;
33 type = FILEID_BTRFS_WITHOUT_PARENT;
34
35 fid->objectid = btrfs_ino(BTRFS_I(inode));
36 fid->root_objectid = BTRFS_I(inode)->root->objectid;
37 fid->gen = inode->i_generation;
38
39 if (parent) {
40 u64 parent_root_id;
41
42 fid->parent_objectid = BTRFS_I(parent)->location.objectid;
43 fid->parent_gen = parent->i_generation;
44 parent_root_id = BTRFS_I(parent)->root->objectid;
45
46 if (parent_root_id != fid->root_objectid) {
47 fid->parent_root_objectid = parent_root_id;
48 len = BTRFS_FID_SIZE_CONNECTABLE_ROOT;
49 type = FILEID_BTRFS_WITH_PARENT_ROOT;
50 } else {
51 len = BTRFS_FID_SIZE_CONNECTABLE;
52 type = FILEID_BTRFS_WITH_PARENT;
53 }
54 }
55
56 *max_len = len;
57 return type;
58}
59
60static struct dentry *btrfs_get_dentry(struct super_block *sb, u64 objectid,
61 u64 root_objectid, u32 generation,
62 int check_generation)
63{
64 struct btrfs_fs_info *fs_info = btrfs_sb(sb);
65 struct btrfs_root *root;
66 struct inode *inode;
67 struct btrfs_key key;
68 int index;
69 int err = 0;
70
71 if (objectid < BTRFS_FIRST_FREE_OBJECTID)
72 return ERR_PTR(-ESTALE);
73
74 key.objectid = root_objectid;
75 key.type = BTRFS_ROOT_ITEM_KEY;
76 key.offset = (u64)-1;
77
78 index = srcu_read_lock(&fs_info->subvol_srcu);
79
80 root = btrfs_read_fs_root_no_name(fs_info, &key);
81 if (IS_ERR(root)) {
82 err = PTR_ERR(root);
83 goto fail;
84 }
85
86 key.objectid = objectid;
87 key.type = BTRFS_INODE_ITEM_KEY;
88 key.offset = 0;
89
90 inode = btrfs_iget(sb, &key, root, NULL);
91 if (IS_ERR(inode)) {
92 err = PTR_ERR(inode);
93 goto fail;
94 }
95
96 srcu_read_unlock(&fs_info->subvol_srcu, index);
97
98 if (check_generation && generation != inode->i_generation) {
99 iput(inode);
100 return ERR_PTR(-ESTALE);
101 }
102
103 return d_obtain_alias(inode);
104fail:
105 srcu_read_unlock(&fs_info->subvol_srcu, index);
106 return ERR_PTR(err);
107}
108
109static struct dentry *btrfs_fh_to_parent(struct super_block *sb, struct fid *fh,
110 int fh_len, int fh_type)
111{
112 struct btrfs_fid *fid = (struct btrfs_fid *) fh;
113 u64 objectid, root_objectid;
114 u32 generation;
115
116 if (fh_type == FILEID_BTRFS_WITH_PARENT) {
117 if (fh_len < BTRFS_FID_SIZE_CONNECTABLE)
118 return NULL;
119 root_objectid = fid->root_objectid;
120 } else if (fh_type == FILEID_BTRFS_WITH_PARENT_ROOT) {
121 if (fh_len < BTRFS_FID_SIZE_CONNECTABLE_ROOT)
122 return NULL;
123 root_objectid = fid->parent_root_objectid;
124 } else
125 return NULL;
126
127 objectid = fid->parent_objectid;
128 generation = fid->parent_gen;
129
130 return btrfs_get_dentry(sb, objectid, root_objectid, generation, 1);
131}
132
133static struct dentry *btrfs_fh_to_dentry(struct super_block *sb, struct fid *fh,
134 int fh_len, int fh_type)
135{
136 struct btrfs_fid *fid = (struct btrfs_fid *) fh;
137 u64 objectid, root_objectid;
138 u32 generation;
139
140 if ((fh_type != FILEID_BTRFS_WITH_PARENT ||
141 fh_len < BTRFS_FID_SIZE_CONNECTABLE) &&
142 (fh_type != FILEID_BTRFS_WITH_PARENT_ROOT ||
143 fh_len < BTRFS_FID_SIZE_CONNECTABLE_ROOT) &&
144 (fh_type != FILEID_BTRFS_WITHOUT_PARENT ||
145 fh_len < BTRFS_FID_SIZE_NON_CONNECTABLE))
146 return NULL;
147
148 objectid = fid->objectid;
149 root_objectid = fid->root_objectid;
150 generation = fid->gen;
151
152 return btrfs_get_dentry(sb, objectid, root_objectid, generation, 1);
153}
154
155static struct dentry *btrfs_get_parent(struct dentry *child)
156{
157 struct inode *dir = d_inode(child);
158 struct btrfs_fs_info *fs_info = btrfs_sb(dir->i_sb);
159 struct btrfs_root *root = BTRFS_I(dir)->root;
160 struct btrfs_path *path;
161 struct extent_buffer *leaf;
162 struct btrfs_root_ref *ref;
163 struct btrfs_key key;
164 struct btrfs_key found_key;
165 int ret;
166
167 path = btrfs_alloc_path();
168 if (!path)
169 return ERR_PTR(-ENOMEM);
170
171 if (btrfs_ino(BTRFS_I(dir)) == BTRFS_FIRST_FREE_OBJECTID) {
172 key.objectid = root->root_key.objectid;
173 key.type = BTRFS_ROOT_BACKREF_KEY;
174 key.offset = (u64)-1;
175 root = fs_info->tree_root;
176 } else {
177 key.objectid = btrfs_ino(BTRFS_I(dir));
178 key.type = BTRFS_INODE_REF_KEY;
179 key.offset = (u64)-1;
180 }
181
182 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
183 if (ret < 0)
184 goto fail;
185
186 BUG_ON(ret == 0);
187 if (path->slots[0] == 0) {
188 ret = -ENOENT;
189 goto fail;
190 }
191
192 path->slots[0]--;
193 leaf = path->nodes[0];
194
195 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
196 if (found_key.objectid != key.objectid || found_key.type != key.type) {
197 ret = -ENOENT;
198 goto fail;
199 }
200
201 if (found_key.type == BTRFS_ROOT_BACKREF_KEY) {
202 ref = btrfs_item_ptr(leaf, path->slots[0],
203 struct btrfs_root_ref);
204 key.objectid = btrfs_root_ref_dirid(leaf, ref);
205 } else {
206 key.objectid = found_key.offset;
207 }
208 btrfs_free_path(path);
209
210 if (found_key.type == BTRFS_ROOT_BACKREF_KEY) {
211 return btrfs_get_dentry(fs_info->sb, key.objectid,
212 found_key.offset, 0, 0);
213 }
214
215 key.type = BTRFS_INODE_ITEM_KEY;
216 key.offset = 0;
217 return d_obtain_alias(btrfs_iget(fs_info->sb, &key, root, NULL));
218fail:
219 btrfs_free_path(path);
220 return ERR_PTR(ret);
221}
222
223static int btrfs_get_name(struct dentry *parent, char *name,
224 struct dentry *child)
225{
226 struct inode *inode = d_inode(child);
227 struct inode *dir = d_inode(parent);
228 struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
229 struct btrfs_path *path;
230 struct btrfs_root *root = BTRFS_I(dir)->root;
231 struct btrfs_inode_ref *iref;
232 struct btrfs_root_ref *rref;
233 struct extent_buffer *leaf;
234 unsigned long name_ptr;
235 struct btrfs_key key;
236 int name_len;
237 int ret;
238 u64 ino;
239
240 if (!S_ISDIR(dir->i_mode))
241 return -EINVAL;
242
243 ino = btrfs_ino(BTRFS_I(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 = fs_info->tree_root;
255 } else {
256 key.objectid = ino;
257 key.offset = btrfs_ino(BTRFS_I(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
