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->root_key.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->root_key.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
60struct 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
68 if (objectid < BTRFS_FIRST_FREE_OBJECTID)
69 return ERR_PTR(-ESTALE);
70
71 root = btrfs_get_fs_root(fs_info, root_objectid, true);
72 if (IS_ERR(root))
73 return ERR_CAST(root);
74
75 inode = btrfs_iget(sb, objectid, root);
76 btrfs_put_root(root);
77 if (IS_ERR(inode))
78 return ERR_CAST(inode);
79
80 if (check_generation && generation != inode->i_generation) {
81 iput(inode);
82 return ERR_PTR(-ESTALE);
83 }
84
85 return d_obtain_alias(inode);
86}
87
88static struct dentry *btrfs_fh_to_parent(struct super_block *sb, struct fid *fh,
89 int fh_len, int fh_type)
90{
91 struct btrfs_fid *fid = (struct btrfs_fid *) fh;
92 u64 objectid, root_objectid;
93 u32 generation;
94
95 if (fh_type == FILEID_BTRFS_WITH_PARENT) {
96 if (fh_len < BTRFS_FID_SIZE_CONNECTABLE)
97 return NULL;
98 root_objectid = fid->root_objectid;
99 } else if (fh_type == FILEID_BTRFS_WITH_PARENT_ROOT) {
100 if (fh_len < BTRFS_FID_SIZE_CONNECTABLE_ROOT)
101 return NULL;
102 root_objectid = fid->parent_root_objectid;
103 } else
104 return NULL;
105
106 objectid = fid->parent_objectid;
107 generation = fid->parent_gen;
108
109 return btrfs_get_dentry(sb, objectid, root_objectid, generation, 1);
110}
111
112static struct dentry *btrfs_fh_to_dentry(struct super_block *sb, struct fid *fh,
113 int fh_len, int fh_type)
114{
115 struct btrfs_fid *fid = (struct btrfs_fid *) fh;
116 u64 objectid, root_objectid;
117 u32 generation;
118
119 if ((fh_type != FILEID_BTRFS_WITH_PARENT ||
120 fh_len < BTRFS_FID_SIZE_CONNECTABLE) &&
121 (fh_type != FILEID_BTRFS_WITH_PARENT_ROOT ||
122 fh_len < BTRFS_FID_SIZE_CONNECTABLE_ROOT) &&
123 (fh_type != FILEID_BTRFS_WITHOUT_PARENT ||
124 fh_len < BTRFS_FID_SIZE_NON_CONNECTABLE))
125 return NULL;
126
127 objectid = fid->objectid;
128 root_objectid = fid->root_objectid;
129 generation = fid->gen;
130
131 return btrfs_get_dentry(sb, objectid, root_objectid, generation, 1);
132}
133
134struct dentry *btrfs_get_parent(struct dentry *child)
135{
136 struct inode *dir = d_inode(child);
137 struct btrfs_fs_info *fs_info = btrfs_sb(dir->i_sb);
138 struct btrfs_root *root = BTRFS_I(dir)->root;
139 struct btrfs_path *path;
140 struct extent_buffer *leaf;
141 struct btrfs_root_ref *ref;
142 struct btrfs_key key;
143 struct btrfs_key found_key;
144 int ret;
145
146 path = btrfs_alloc_path();
147 if (!path)
148 return ERR_PTR(-ENOMEM);
149
150 if (btrfs_ino(BTRFS_I(dir)) == BTRFS_FIRST_FREE_OBJECTID) {
151 key.objectid = root->root_key.objectid;
152 key.type = BTRFS_ROOT_BACKREF_KEY;
153 key.offset = (u64)-1;
154 root = fs_info->tree_root;
155 } else {
156 key.objectid = btrfs_ino(BTRFS_I(dir));
157 key.type = BTRFS_INODE_REF_KEY;
158 key.offset = (u64)-1;
159 }
160
161 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
162 if (ret < 0)
163 goto fail;
164
165 BUG_ON(ret == 0);
166 if (path->slots[0] == 0) {
167 ret = -ENOENT;
168 goto fail;
169 }
170
171 path->slots[0]--;
172 leaf = path->nodes[0];
173
174 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
175 if (found_key.objectid != key.objectid || found_key.type != key.type) {
176 ret = -ENOENT;
177 goto fail;
178 }
179
180 if (found_key.type == BTRFS_ROOT_BACKREF_KEY) {
181 ref = btrfs_item_ptr(leaf, path->slots[0],
182 struct btrfs_root_ref);
183 key.objectid = btrfs_root_ref_dirid(leaf, ref);
184 } else {
185 key.objectid = found_key.offset;
186 }
187 btrfs_free_path(path);
188
189 if (found_key.type == BTRFS_ROOT_BACKREF_KEY) {
190 return btrfs_get_dentry(fs_info->sb, key.objectid,
191 found_key.offset, 0, 0);
192 }
193
194 return d_obtain_alias(btrfs_iget(fs_info->sb, key.objectid, root));
195fail:
196 btrfs_free_path(path);
197 return ERR_PTR(ret);
198}
199
200static int btrfs_get_name(struct dentry *parent, char *name,
201 struct dentry *child)
202{
203 struct inode *inode = d_inode(child);
204 struct inode *dir = d_inode(parent);
205 struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
206 struct btrfs_path *path;
207 struct btrfs_root *root = BTRFS_I(dir)->root;
208 struct btrfs_inode_ref *iref;
209 struct btrfs_root_ref *rref;
210 struct extent_buffer *leaf;
211 unsigned long name_ptr;
212 struct btrfs_key key;
213 int name_len;
214 int ret;
215 u64 ino;
216
217 if (!S_ISDIR(dir->i_mode))
218 return -EINVAL;
219
220 ino = btrfs_ino(BTRFS_I(inode));
221
222 path = btrfs_alloc_path();
223 if (!path)
224 return -ENOMEM;
225
226 if (ino == BTRFS_FIRST_FREE_OBJECTID) {
227 key.objectid = BTRFS_I(inode)->root->root_key.objectid;
228 key.type = BTRFS_ROOT_BACKREF_KEY;
229 key.offset = (u64)-1;
230 root = fs_info->tree_root;
231 } else {
232 key.objectid = ino;
233 key.offset = btrfs_ino(BTRFS_I(dir));
234 key.type = BTRFS_INODE_REF_KEY;
235 }
236
237 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
238 if (ret < 0) {
239 btrfs_free_path(path);
240 return ret;
241 } else if (ret > 0) {
242 if (ino == BTRFS_FIRST_FREE_OBJECTID) {
243 path->slots[0]--;
244 } else {
245 btrfs_free_path(path);
246 return -ENOENT;
247 }
248 }
249 leaf = path->nodes[0];
250
251 if (ino == BTRFS_FIRST_FREE_OBJECTID) {
252 rref = btrfs_item_ptr(leaf, path->slots[0],
253 struct btrfs_root_ref);
254 name_ptr = (unsigned long)(rref + 1);
255 name_len = btrfs_root_ref_name_len(leaf, rref);
256 } else {
257 iref = btrfs_item_ptr(leaf, path->slots[0],
258 struct btrfs_inode_ref);
259 name_ptr = (unsigned long)(iref + 1);
260 name_len = btrfs_inode_ref_name_len(leaf, iref);
261 }
262
263 read_extent_buffer(leaf, name, name_ptr, name_len);
264 btrfs_free_path(path);
265
266
267
268
269
270 name[name_len] = '\0';
271
272 return 0;
273}
274
275const struct export_operations btrfs_export_ops = {
276 .encode_fh = btrfs_encode_fh,
277 .fh_to_dentry = btrfs_fh_to_dentry,
278 .fh_to_parent = btrfs_fh_to_parent,
279 .get_parent = btrfs_get_parent,
280 .get_name = btrfs_get_name,
281};
282
