1
2#include <linux/fs.h>
3#include <linux/types.h>
4#include "ctree.h"
5#include "disk-io.h"
6#include "btrfs_inode.h"
7#include "print-tree.h"
8#include "export.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(BTRFS_I(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 key.type = 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 key.type = 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 = d_inode(child);
157 struct btrfs_fs_info *fs_info = btrfs_sb(dir->i_sb);
158 struct btrfs_root *root = BTRFS_I(dir)->root;
159 struct btrfs_path *path;
160 struct extent_buffer *leaf;
161 struct btrfs_root_ref *ref;
162 struct btrfs_key key;
163 struct btrfs_key found_key;
164 int ret;
165
166 path = btrfs_alloc_path();
167 if (!path)
168 return ERR_PTR(-ENOMEM);
169
170 if (btrfs_ino(BTRFS_I(dir)) == BTRFS_FIRST_FREE_OBJECTID) {
171 key.objectid = root->root_key.objectid;
172 key.type = BTRFS_ROOT_BACKREF_KEY;
173 key.offset = (u64)-1;
174 root = fs_info->tree_root;
175 } else {
176 key.objectid = btrfs_ino(BTRFS_I(dir));
177 key.type = BTRFS_INODE_REF_KEY;
178 key.offset = (u64)-1;
179 }
180
181 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
182 if (ret < 0)
183 goto fail;
184
185 BUG_ON(ret == 0);
186 if (path->slots[0] == 0) {
187 ret = -ENOENT;
188 goto fail;
189 }
190
191 path->slots[0]--;
192 leaf = path->nodes[0];
193
194 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
195 if (found_key.objectid != key.objectid || found_key.type != key.type) {
196 ret = -ENOENT;
197 goto fail;
198 }
199
200 if (found_key.type == BTRFS_ROOT_BACKREF_KEY) {
201 ref = btrfs_item_ptr(leaf, path->slots[0],
202 struct btrfs_root_ref);
203 key.objectid = btrfs_root_ref_dirid(leaf, ref);
204 } else {
205 key.objectid = found_key.offset;
206 }
207 btrfs_free_path(path);
208
209 if (found_key.type == BTRFS_ROOT_BACKREF_KEY) {
210 return btrfs_get_dentry(fs_info->sb, key.objectid,
211 found_key.offset, 0, 0);
212 }
213
214 key.type = BTRFS_INODE_ITEM_KEY;
215 key.offset = 0;
216 return d_obtain_alias(btrfs_iget(fs_info->sb, &key, root, NULL));
217fail:
218 btrfs_free_path(path);
219 return ERR_PTR(ret);
220}
221
222static int btrfs_get_name(struct dentry *parent, char *name,
223 struct dentry *child)
224{
225 struct inode *inode = d_inode(child);
226 struct inode *dir = d_inode(parent);
227 struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
228 struct btrfs_path *path;
229 struct btrfs_root *root = BTRFS_I(dir)->root;
230 struct btrfs_inode_ref *iref;
231 struct btrfs_root_ref *rref;
232 struct extent_buffer *leaf;
233 unsigned long name_ptr;
234 struct btrfs_key key;
235 int name_len;
236 int ret;
237 u64 ino;
238
239 if (!S_ISDIR(dir->i_mode))
240 return -EINVAL;
241
242 ino = btrfs_ino(BTRFS_I(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 = fs_info->tree_root;
254 } else {
255 key.objectid = ino;
256 key.offset = btrfs_ino(BTRFS_I(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 ret = btrfs_is_name_len_valid(leaf, path->slots[0], name_ptr, name_len);
287 if (!ret) {
288 btrfs_free_path(path);
289 return -EIO;
290 }
291 read_extent_buffer(leaf, name, name_ptr, name_len);
292 btrfs_free_path(path);
293
294
295
296
297
298 name[name_len] = '\0';
299
300 return 0;
301}
302
303const struct export_operations btrfs_export_ops = {
304 .encode_fh = btrfs_encode_fh,
305 .fh_to_dentry = btrfs_fh_to_dentry,
306 .fh_to_parent = btrfs_fh_to_parent,
307 .get_parent = btrfs_get_parent,
308 .get_name = btrfs_get_name,
309};
310
