]> git.karo-electronics.de Git - karo-tx-linux.git/blob - fs/btrfs/export.c
Merge branch 'iommu-for-tony' of git://github.com/ohadbc/omap-iommu into devel-fixes
[karo-tx-linux.git] / fs / btrfs / export.c
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
16 static int btrfs_encode_fh(struct dentry *dentry, u32 *fh, int *max_len,
17                            int connectable)
18 {
19         struct btrfs_fid *fid = (struct btrfs_fid *)fh;
20         struct inode *inode = dentry->d_inode;
21         int len = *max_len;
22         int type;
23
24         if (connectable && (len < BTRFS_FID_SIZE_CONNECTABLE)) {
25                 *max_len = BTRFS_FID_SIZE_CONNECTABLE;
26                 return 255;
27         } else if (len < BTRFS_FID_SIZE_NON_CONNECTABLE) {
28                 *max_len = BTRFS_FID_SIZE_NON_CONNECTABLE;
29                 return 255;
30         }
31
32         len  = BTRFS_FID_SIZE_NON_CONNECTABLE;
33         type = FILEID_BTRFS_WITHOUT_PARENT;
34
35         fid->objectid = btrfs_ino(inode);
36         fid->root_objectid = BTRFS_I(inode)->root->objectid;
37         fid->gen = inode->i_generation;
38
39         if (connectable && !S_ISDIR(inode->i_mode)) {
40                 struct inode *parent;
41                 u64 parent_root_id;
42
43                 spin_lock(&dentry->d_lock);
44
45                 parent = dentry->d_parent->d_inode;
46                 fid->parent_objectid = BTRFS_I(parent)->location.objectid;
47                 fid->parent_gen = parent->i_generation;
48                 parent_root_id = BTRFS_I(parent)->root->objectid;
49
50                 spin_unlock(&dentry->d_lock);
51
52                 if (parent_root_id != fid->root_objectid) {
53                         fid->parent_root_objectid = parent_root_id;
54                         len = BTRFS_FID_SIZE_CONNECTABLE_ROOT;
55                         type = FILEID_BTRFS_WITH_PARENT_ROOT;
56                 } else {
57                         len = BTRFS_FID_SIZE_CONNECTABLE;
58                         type = FILEID_BTRFS_WITH_PARENT;
59                 }
60         }
61
62         *max_len = len;
63         return type;
64 }
65
66 static struct dentry *btrfs_get_dentry(struct super_block *sb, u64 objectid,
67                                        u64 root_objectid, u32 generation,
68                                        int check_generation)
69 {
70         struct btrfs_fs_info *fs_info = btrfs_sb(sb)->fs_info;
71         struct btrfs_root *root;
72         struct inode *inode;
73         struct btrfs_key key;
74         int index;
75         int err = 0;
76
77         if (objectid < BTRFS_FIRST_FREE_OBJECTID)
78                 return ERR_PTR(-ESTALE);
79
80         key.objectid = root_objectid;
81         btrfs_set_key_type(&key, BTRFS_ROOT_ITEM_KEY);
82         key.offset = (u64)-1;
83
84         index = srcu_read_lock(&fs_info->subvol_srcu);
85
86         root = btrfs_read_fs_root_no_name(fs_info, &key);
87         if (IS_ERR(root)) {
88                 err = PTR_ERR(root);
89                 goto fail;
90         }
91
92         if (btrfs_root_refs(&root->root_item) == 0) {
93                 err = -ENOENT;
94                 goto fail;
95         }
96
97         key.objectid = objectid;
98         btrfs_set_key_type(&key, BTRFS_INODE_ITEM_KEY);
99         key.offset = 0;
100
101         inode = btrfs_iget(sb, &key, root, NULL);
102         if (IS_ERR(inode)) {
103                 err = PTR_ERR(inode);
104                 goto fail;
105         }
106
107         srcu_read_unlock(&fs_info->subvol_srcu, index);
108
109         if (check_generation && generation != inode->i_generation) {
110                 iput(inode);
111                 return ERR_PTR(-ESTALE);
112         }
113
114         return d_obtain_alias(inode);
115 fail:
116         srcu_read_unlock(&fs_info->subvol_srcu, index);
117         return ERR_PTR(err);
118 }
119
120 static struct dentry *btrfs_fh_to_parent(struct super_block *sb, struct fid *fh,
121                                          int fh_len, int fh_type)
122 {
123         struct btrfs_fid *fid = (struct btrfs_fid *) fh;
124         u64 objectid, root_objectid;
125         u32 generation;
126
127         if (fh_type == FILEID_BTRFS_WITH_PARENT) {
128                 if (fh_len !=  BTRFS_FID_SIZE_CONNECTABLE)
129                         return NULL;
130                 root_objectid = fid->root_objectid;
131         } else if (fh_type == FILEID_BTRFS_WITH_PARENT_ROOT) {
132                 if (fh_len != BTRFS_FID_SIZE_CONNECTABLE_ROOT)
133                         return NULL;
134                 root_objectid = fid->parent_root_objectid;
135         } else
136                 return NULL;
137
138         objectid = fid->parent_objectid;
139         generation = fid->parent_gen;
140
141         return btrfs_get_dentry(sb, objectid, root_objectid, generation, 1);
142 }
143
144 static struct dentry *btrfs_fh_to_dentry(struct super_block *sb, struct fid *fh,
145                                          int fh_len, int fh_type)
146 {
147         struct btrfs_fid *fid = (struct btrfs_fid *) fh;
148         u64 objectid, root_objectid;
149         u32 generation;
150
151         if ((fh_type != FILEID_BTRFS_WITH_PARENT ||
152              fh_len != BTRFS_FID_SIZE_CONNECTABLE) &&
153             (fh_type != FILEID_BTRFS_WITH_PARENT_ROOT ||
154              fh_len != BTRFS_FID_SIZE_CONNECTABLE_ROOT) &&
155             (fh_type != FILEID_BTRFS_WITHOUT_PARENT ||
156              fh_len != BTRFS_FID_SIZE_NON_CONNECTABLE))
157                 return NULL;
158
159         objectid = fid->objectid;
160         root_objectid = fid->root_objectid;
161         generation = fid->gen;
162
163         return btrfs_get_dentry(sb, objectid, root_objectid, generation, 1);
164 }
165
166 static struct dentry *btrfs_get_parent(struct dentry *child)
167 {
168         struct inode *dir = child->d_inode;
169         struct btrfs_root *root = BTRFS_I(dir)->root;
170         struct btrfs_path *path;
171         struct extent_buffer *leaf;
172         struct btrfs_root_ref *ref;
173         struct btrfs_key key;
174         struct btrfs_key found_key;
175         int ret;
176
177         path = btrfs_alloc_path();
178         if (!path)
179                 return ERR_PTR(-ENOMEM);
180
181         if (btrfs_ino(dir) == BTRFS_FIRST_FREE_OBJECTID) {
182                 key.objectid = root->root_key.objectid;
183                 key.type = BTRFS_ROOT_BACKREF_KEY;
184                 key.offset = (u64)-1;
185                 root = root->fs_info->tree_root;
186         } else {
187                 key.objectid = btrfs_ino(dir);
188                 key.type = BTRFS_INODE_REF_KEY;
189                 key.offset = (u64)-1;
190         }
191
192         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
193         if (ret < 0)
194                 goto fail;
195
196         BUG_ON(ret == 0);
197         if (path->slots[0] == 0) {
198                 ret = -ENOENT;
199                 goto fail;
200         }
201
202         path->slots[0]--;
203         leaf = path->nodes[0];
204
205         btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
206         if (found_key.objectid != key.objectid || found_key.type != key.type) {
207                 ret = -ENOENT;
208                 goto fail;
209         }
210
211         if (found_key.type == BTRFS_ROOT_BACKREF_KEY) {
212                 ref = btrfs_item_ptr(leaf, path->slots[0],
213                                      struct btrfs_root_ref);
214                 key.objectid = btrfs_root_ref_dirid(leaf, ref);
215         } else {
216                 key.objectid = found_key.offset;
217         }
218         btrfs_free_path(path);
219
220         if (found_key.type == BTRFS_ROOT_BACKREF_KEY) {
221                 return btrfs_get_dentry(root->fs_info->sb, key.objectid,
222                                         found_key.offset, 0, 0);
223         }
224
225         key.type = BTRFS_INODE_ITEM_KEY;
226         key.offset = 0;
227         return d_obtain_alias(btrfs_iget(root->fs_info->sb, &key, root, NULL));
228 fail:
229         btrfs_free_path(path);
230         return ERR_PTR(ret);
231 }
232
233 static int btrfs_get_name(struct dentry *parent, char *name,
234                           struct dentry *child)
235 {
236         struct inode *inode = child->d_inode;
237         struct inode *dir = parent->d_inode;
238         struct btrfs_path *path;
239         struct btrfs_root *root = BTRFS_I(dir)->root;
240         struct btrfs_inode_ref *iref;
241         struct btrfs_root_ref *rref;
242         struct extent_buffer *leaf;
243         unsigned long name_ptr;
244         struct btrfs_key key;
245         int name_len;
246         int ret;
247         u64 ino;
248
249         if (!dir || !inode)
250                 return -EINVAL;
251
252         if (!S_ISDIR(dir->i_mode))
253                 return -EINVAL;
254
255         ino = btrfs_ino(inode);
256
257         path = btrfs_alloc_path();
258         if (!path)
259                 return -ENOMEM;
260         path->leave_spinning = 1;
261
262         if (ino == BTRFS_FIRST_FREE_OBJECTID) {
263                 key.objectid = BTRFS_I(inode)->root->root_key.objectid;
264                 key.type = BTRFS_ROOT_BACKREF_KEY;
265                 key.offset = (u64)-1;
266                 root = root->fs_info->tree_root;
267         } else {
268                 key.objectid = ino;
269                 key.offset = btrfs_ino(dir);
270                 key.type = BTRFS_INODE_REF_KEY;
271         }
272
273         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
274         if (ret < 0) {
275                 btrfs_free_path(path);
276                 return ret;
277         } else if (ret > 0) {
278                 if (ino == BTRFS_FIRST_FREE_OBJECTID) {
279                         path->slots[0]--;
280                 } else {
281                         btrfs_free_path(path);
282                         return -ENOENT;
283                 }
284         }
285         leaf = path->nodes[0];
286
287         if (ino == BTRFS_FIRST_FREE_OBJECTID) {
288                 rref = btrfs_item_ptr(leaf, path->slots[0],
289                                      struct btrfs_root_ref);
290                 name_ptr = (unsigned long)(rref + 1);
291                 name_len = btrfs_root_ref_name_len(leaf, rref);
292         } else {
293                 iref = btrfs_item_ptr(leaf, path->slots[0],
294                                       struct btrfs_inode_ref);
295                 name_ptr = (unsigned long)(iref + 1);
296                 name_len = btrfs_inode_ref_name_len(leaf, iref);
297         }
298
299         read_extent_buffer(leaf, name, name_ptr, name_len);
300         btrfs_free_path(path);
301
302         /*
303          * have to add the null termination to make sure that reconnect_path
304          * gets the right len for strlen
305          */
306         name[name_len] = '\0';
307
308         return 0;
309 }
310
311 const struct export_operations btrfs_export_ops = {
312         .encode_fh      = btrfs_encode_fh,
313         .fh_to_dentry   = btrfs_fh_to_dentry,
314         .fh_to_parent   = btrfs_fh_to_parent,
315         .get_parent     = btrfs_get_parent,
316         .get_name       = btrfs_get_name,
317 };