Line data Source code
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 :
15 0 : static 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 0 : int len = *max_len;
20 : int type;
21 :
22 0 : if (parent && (len < BTRFS_FID_SIZE_CONNECTABLE)) {
23 0 : *max_len = BTRFS_FID_SIZE_CONNECTABLE;
24 0 : return FILEID_INVALID;
25 0 : } else if (len < BTRFS_FID_SIZE_NON_CONNECTABLE) {
26 0 : *max_len = BTRFS_FID_SIZE_NON_CONNECTABLE;
27 0 : return FILEID_INVALID;
28 : }
29 :
30 : len = BTRFS_FID_SIZE_NON_CONNECTABLE;
31 : type = FILEID_BTRFS_WITHOUT_PARENT;
32 :
33 0 : fid->objectid = btrfs_ino(inode);
34 0 : fid->root_objectid = BTRFS_I(inode)->root->objectid;
35 0 : fid->gen = inode->i_generation;
36 :
37 0 : if (parent) {
38 : u64 parent_root_id;
39 :
40 0 : fid->parent_objectid = BTRFS_I(parent)->location.objectid;
41 0 : fid->parent_gen = parent->i_generation;
42 0 : parent_root_id = BTRFS_I(parent)->root->objectid;
43 :
44 0 : if (parent_root_id != fid->root_objectid) {
45 0 : 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 0 : *max_len = len;
55 0 : return type;
56 : }
57 :
58 0 : static 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 0 : if (objectid < BTRFS_FIRST_FREE_OBJECTID)
70 : return ERR_PTR(-ESTALE);
71 :
72 0 : key.objectid = root_objectid;
73 : btrfs_set_key_type(&key, BTRFS_ROOT_ITEM_KEY);
74 0 : key.offset = (u64)-1;
75 :
76 0 : index = srcu_read_lock(&fs_info->subvol_srcu);
77 :
78 : root = btrfs_read_fs_root_no_name(fs_info, &key);
79 0 : if (IS_ERR(root)) {
80 0 : err = PTR_ERR(root);
81 0 : goto fail;
82 : }
83 :
84 0 : key.objectid = objectid;
85 : btrfs_set_key_type(&key, BTRFS_INODE_ITEM_KEY);
86 0 : key.offset = 0;
87 :
88 0 : inode = btrfs_iget(sb, &key, root, NULL);
89 0 : if (IS_ERR(inode)) {
90 0 : err = PTR_ERR(inode);
91 0 : goto fail;
92 : }
93 :
94 : srcu_read_unlock(&fs_info->subvol_srcu, index);
95 :
96 0 : if (check_generation && generation != inode->i_generation) {
97 0 : iput(inode);
98 0 : return ERR_PTR(-ESTALE);
99 : }
100 :
101 0 : return d_obtain_alias(inode);
102 : fail:
103 : srcu_read_unlock(&fs_info->subvol_srcu, index);
104 0 : return ERR_PTR(err);
105 : }
106 :
107 0 : static 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 0 : if (fh_type == FILEID_BTRFS_WITH_PARENT) {
115 0 : if (fh_len != BTRFS_FID_SIZE_CONNECTABLE)
116 : return NULL;
117 0 : root_objectid = fid->root_objectid;
118 0 : } else if (fh_type == FILEID_BTRFS_WITH_PARENT_ROOT) {
119 0 : if (fh_len != BTRFS_FID_SIZE_CONNECTABLE_ROOT)
120 : return NULL;
121 0 : root_objectid = fid->parent_root_objectid;
122 : } else
123 : return NULL;
124 :
125 0 : objectid = fid->parent_objectid;
126 0 : generation = fid->parent_gen;
127 :
128 0 : return btrfs_get_dentry(sb, objectid, root_objectid, generation, 1);
129 : }
130 :
131 0 : static 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 0 : if ((fh_type != FILEID_BTRFS_WITH_PARENT ||
139 0 : fh_len != BTRFS_FID_SIZE_CONNECTABLE) &&
140 0 : (fh_type != FILEID_BTRFS_WITH_PARENT_ROOT ||
141 0 : fh_len != BTRFS_FID_SIZE_CONNECTABLE_ROOT) &&
142 0 : (fh_type != FILEID_BTRFS_WITHOUT_PARENT ||
143 0 : fh_len != BTRFS_FID_SIZE_NON_CONNECTABLE))
144 : return NULL;
145 :
146 0 : objectid = fid->objectid;
147 0 : root_objectid = fid->root_objectid;
148 0 : generation = fid->gen;
149 :
150 0 : return btrfs_get_dentry(sb, objectid, root_objectid, generation, 1);
151 : }
152 :
153 0 : static struct dentry *btrfs_get_parent(struct dentry *child)
154 : {
155 0 : struct inode *dir = child->d_inode;
156 0 : 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 0 : path = btrfs_alloc_path();
165 0 : if (!path)
166 : return ERR_PTR(-ENOMEM);
167 :
168 0 : if (btrfs_ino(dir) == BTRFS_FIRST_FREE_OBJECTID) {
169 0 : key.objectid = root->root_key.objectid;
170 0 : key.type = BTRFS_ROOT_BACKREF_KEY;
171 0 : key.offset = (u64)-1;
172 0 : root = root->fs_info->tree_root;
173 : } else {
174 0 : key.objectid = btrfs_ino(dir);
175 0 : key.type = BTRFS_INODE_REF_KEY;
176 0 : key.offset = (u64)-1;
177 : }
178 :
179 0 : ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
180 0 : if (ret < 0)
181 : goto fail;
182 :
183 0 : BUG_ON(ret == 0); /* Key with offset of -1 found */
184 0 : if (path->slots[0] == 0) {
185 : ret = -ENOENT;
186 : goto fail;
187 : }
188 :
189 0 : path->slots[0]--;
190 0 : leaf = path->nodes[0];
191 :
192 0 : btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
193 0 : if (found_key.objectid != key.objectid || found_key.type != key.type) {
194 : ret = -ENOENT;
195 : goto fail;
196 : }
197 :
198 0 : if (found_key.type == BTRFS_ROOT_BACKREF_KEY) {
199 0 : ref = btrfs_item_ptr(leaf, path->slots[0],
200 : struct btrfs_root_ref);
201 0 : key.objectid = btrfs_root_ref_dirid(leaf, ref);
202 : } else {
203 0 : key.objectid = found_key.offset;
204 : }
205 0 : btrfs_free_path(path);
206 :
207 0 : if (found_key.type == BTRFS_ROOT_BACKREF_KEY) {
208 0 : return btrfs_get_dentry(root->fs_info->sb, key.objectid,
209 : found_key.offset, 0, 0);
210 : }
211 :
212 0 : key.type = BTRFS_INODE_ITEM_KEY;
213 0 : key.offset = 0;
214 0 : return d_obtain_alias(btrfs_iget(root->fs_info->sb, &key, root, NULL));
215 : fail:
216 0 : btrfs_free_path(path);
217 0 : return ERR_PTR(ret);
218 : }
219 :
220 0 : static int btrfs_get_name(struct dentry *parent, char *name,
221 : struct dentry *child)
222 : {
223 0 : struct inode *inode = child->d_inode;
224 0 : struct inode *dir = parent->d_inode;
225 : struct btrfs_path *path;
226 0 : 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 0 : if (!dir || !inode)
237 : return -EINVAL;
238 :
239 0 : if (!S_ISDIR(dir->i_mode))
240 : return -EINVAL;
241 :
242 : ino = btrfs_ino(inode);
243 :
244 0 : path = btrfs_alloc_path();
245 0 : if (!path)
246 : return -ENOMEM;
247 0 : path->leave_spinning = 1;
248 :
249 0 : if (ino == BTRFS_FIRST_FREE_OBJECTID) {
250 0 : key.objectid = BTRFS_I(inode)->root->root_key.objectid;
251 0 : key.type = BTRFS_ROOT_BACKREF_KEY;
252 0 : key.offset = (u64)-1;
253 0 : root = root->fs_info->tree_root;
254 : } else {
255 0 : key.objectid = ino;
256 0 : key.offset = btrfs_ino(dir);
257 0 : key.type = BTRFS_INODE_REF_KEY;
258 : }
259 :
260 0 : ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
261 0 : if (ret < 0) {
262 0 : btrfs_free_path(path);
263 0 : return ret;
264 0 : } else if (ret > 0) {
265 0 : if (ino == BTRFS_FIRST_FREE_OBJECTID) {
266 0 : path->slots[0]--;
267 : } else {
268 0 : btrfs_free_path(path);
269 0 : return -ENOENT;
270 : }
271 : }
272 0 : leaf = path->nodes[0];
273 :
274 0 : if (ino == BTRFS_FIRST_FREE_OBJECTID) {
275 0 : rref = btrfs_item_ptr(leaf, path->slots[0],
276 : struct btrfs_root_ref);
277 0 : name_ptr = (unsigned long)(rref + 1);
278 0 : name_len = btrfs_root_ref_name_len(leaf, rref);
279 : } else {
280 0 : iref = btrfs_item_ptr(leaf, path->slots[0],
281 : struct btrfs_inode_ref);
282 0 : name_ptr = (unsigned long)(iref + 1);
283 0 : name_len = btrfs_inode_ref_name_len(leaf, iref);
284 : }
285 :
286 0 : read_extent_buffer(leaf, name, name_ptr, name_len);
287 0 : btrfs_free_path(path);
288 :
289 : /*
290 : * have to add the null termination to make sure that reconnect_path
291 : * gets the right len for strlen
292 : */
293 0 : name[name_len] = '\0';
294 :
295 0 : return 0;
296 : }
297 :
298 : const 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 : };
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