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TOMOYO Linux Cross Reference
Linux/fs/btrfs/export.c

Version: ~ [ linux-5.19-rc3 ] ~ [ linux-5.18.5 ] ~ [ linux-5.17.15 ] ~ [ linux-5.16.20 ] ~ [ linux-5.15.48 ] ~ [ linux-5.14.21 ] ~ [ linux-5.13.19 ] ~ [ linux-5.12.19 ] ~ [ linux-5.11.22 ] ~ [ linux-5.10.123 ] ~ [ linux-5.9.16 ] ~ [ linux-5.8.18 ] ~ [ linux-5.7.19 ] ~ [ linux-5.6.19 ] ~ [ linux-5.5.19 ] ~ [ linux-5.4.199 ] ~ [ linux-5.3.18 ] ~ [ linux-5.2.21 ] ~ [ linux-5.1.21 ] ~ [ linux-5.0.21 ] ~ [ linux-4.20.17 ] ~ [ linux-4.19.248 ] ~ [ linux-4.18.20 ] ~ [ linux-4.17.19 ] ~ [ linux-4.16.18 ] ~ [ linux-4.15.18 ] ~ [ linux-4.14.284 ] ~ [ linux-4.13.16 ] ~ [ linux-4.12.14 ] ~ [ linux-4.11.12 ] ~ [ linux-4.10.17 ] ~ [ linux-4.9.319 ] ~ [ linux-4.8.17 ] ~ [ linux-4.7.10 ] ~ [ linux-4.6.7 ] ~ [ linux-4.5.7 ] ~ [ linux-4.4.302 ] ~ [ linux-4.3.6 ] ~ [ linux-4.2.8 ] ~ [ linux-4.1.52 ] ~ [ linux-4.0.9 ] ~ [ linux-3.10.108 ] ~ [ linux-2.6.32.71 ] ~ [ linux-2.6.0 ] ~ [ linux-2.4.37.11 ] ~ [ unix-v6-master ] ~ [ ccs-tools-1.8.9 ] ~ [ policy-sample ] ~
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  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 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         int len = *max_len;
 20         int type;
 21 
 22         if (parent && (len < BTRFS_FID_SIZE_CONNECTABLE)) {
 23                 *max_len = BTRFS_FID_SIZE_CONNECTABLE;
 24                 return FILEID_INVALID;
 25         } else if (len < BTRFS_FID_SIZE_NON_CONNECTABLE) {
 26                 *max_len = BTRFS_FID_SIZE_NON_CONNECTABLE;
 27                 return FILEID_INVALID;
 28         }
 29 
 30         len  = BTRFS_FID_SIZE_NON_CONNECTABLE;
 31         type = FILEID_BTRFS_WITHOUT_PARENT;
 32 
 33         fid->objectid = btrfs_ino(inode);
 34         fid->root_objectid = BTRFS_I(inode)->root->objectid;
 35         fid->gen = inode->i_generation;
 36 
 37         if (parent) {
 38                 u64 parent_root_id;
 39 
 40                 fid->parent_objectid = BTRFS_I(parent)->location.objectid;
 41                 fid->parent_gen = parent->i_generation;
 42                 parent_root_id = BTRFS_I(parent)->root->objectid;
 43 
 44                 if (parent_root_id != fid->root_objectid) {
 45                         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         *max_len = len;
 55         return type;
 56 }
 57 
 58 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         if (objectid < BTRFS_FIRST_FREE_OBJECTID)
 70                 return ERR_PTR(-ESTALE);
 71 
 72         key.objectid = root_objectid;
 73         key.type = BTRFS_ROOT_ITEM_KEY;
 74         key.offset = (u64)-1;
 75 
 76         index = srcu_read_lock(&fs_info->subvol_srcu);
 77 
 78         root = btrfs_read_fs_root_no_name(fs_info, &key);
 79         if (IS_ERR(root)) {
 80                 err = PTR_ERR(root);
 81                 goto fail;
 82         }
 83 
 84         key.objectid = objectid;
 85         key.type = BTRFS_INODE_ITEM_KEY;
 86         key.offset = 0;
 87 
 88         inode = btrfs_iget(sb, &key, root, NULL);
 89         if (IS_ERR(inode)) {
 90                 err = PTR_ERR(inode);
 91                 goto fail;
 92         }
 93 
 94         srcu_read_unlock(&fs_info->subvol_srcu, index);
 95 
 96         if (check_generation && generation != inode->i_generation) {
 97                 iput(inode);
 98                 return ERR_PTR(-ESTALE);
 99         }
100 
101         return d_obtain_alias(inode);
102 fail:
103         srcu_read_unlock(&fs_info->subvol_srcu, index);
104         return ERR_PTR(err);
105 }
106 
107 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         if (fh_type == FILEID_BTRFS_WITH_PARENT) {
115                 if (fh_len <  BTRFS_FID_SIZE_CONNECTABLE)
116                         return NULL;
117                 root_objectid = fid->root_objectid;
118         } else if (fh_type == FILEID_BTRFS_WITH_PARENT_ROOT) {
119                 if (fh_len < BTRFS_FID_SIZE_CONNECTABLE_ROOT)
120                         return NULL;
121                 root_objectid = fid->parent_root_objectid;
122         } else
123                 return NULL;
124 
125         objectid = fid->parent_objectid;
126         generation = fid->parent_gen;
127 
128         return btrfs_get_dentry(sb, objectid, root_objectid, generation, 1);
129 }
130 
131 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         if ((fh_type != FILEID_BTRFS_WITH_PARENT ||
139              fh_len < BTRFS_FID_SIZE_CONNECTABLE) &&
140             (fh_type != FILEID_BTRFS_WITH_PARENT_ROOT ||
141              fh_len < BTRFS_FID_SIZE_CONNECTABLE_ROOT) &&
142             (fh_type != FILEID_BTRFS_WITHOUT_PARENT ||
143              fh_len < BTRFS_FID_SIZE_NON_CONNECTABLE))
144                 return NULL;
145 
146         objectid = fid->objectid;
147         root_objectid = fid->root_objectid;
148         generation = fid->gen;
149 
150         return btrfs_get_dentry(sb, objectid, root_objectid, generation, 1);
151 }
152 
153 static struct dentry *btrfs_get_parent(struct dentry *child)
154 {
155         struct inode *dir = d_inode(child);
156         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         path = btrfs_alloc_path();
165         if (!path)
166                 return ERR_PTR(-ENOMEM);
167 
168         if (btrfs_ino(dir) == BTRFS_FIRST_FREE_OBJECTID) {
169                 key.objectid = root->root_key.objectid;
170                 key.type = BTRFS_ROOT_BACKREF_KEY;
171                 key.offset = (u64)-1;
172                 root = root->fs_info->tree_root;
173         } else {
174                 key.objectid = btrfs_ino(dir);
175                 key.type = BTRFS_INODE_REF_KEY;
176                 key.offset = (u64)-1;
177         }
178 
179         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
180         if (ret < 0)
181                 goto fail;
182 
183         BUG_ON(ret == 0); /* Key with offset of -1 found */
184         if (path->slots[0] == 0) {
185                 ret = -ENOENT;
186                 goto fail;
187         }
188 
189         path->slots[0]--;
190         leaf = path->nodes[0];
191 
192         btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
193         if (found_key.objectid != key.objectid || found_key.type != key.type) {
194                 ret = -ENOENT;
195                 goto fail;
196         }
197 
198         if (found_key.type == BTRFS_ROOT_BACKREF_KEY) {
199                 ref = btrfs_item_ptr(leaf, path->slots[0],
200                                      struct btrfs_root_ref);
201                 key.objectid = btrfs_root_ref_dirid(leaf, ref);
202         } else {
203                 key.objectid = found_key.offset;
204         }
205         btrfs_free_path(path);
206 
207         if (found_key.type == BTRFS_ROOT_BACKREF_KEY) {
208                 return btrfs_get_dentry(root->fs_info->sb, key.objectid,
209                                         found_key.offset, 0, 0);
210         }
211 
212         key.type = BTRFS_INODE_ITEM_KEY;
213         key.offset = 0;
214         return d_obtain_alias(btrfs_iget(root->fs_info->sb, &key, root, NULL));
215 fail:
216         btrfs_free_path(path);
217         return ERR_PTR(ret);
218 }
219 
220 static int btrfs_get_name(struct dentry *parent, char *name,
221                           struct dentry *child)
222 {
223         struct inode *inode = d_inode(child);
224         struct inode *dir = d_inode(parent);
225         struct btrfs_path *path;
226         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         if (!dir || !inode)
237                 return -EINVAL;
238 
239         if (!S_ISDIR(dir->i_mode))
240                 return -EINVAL;
241 
242         ino = btrfs_ino(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 = root->fs_info->tree_root;
254         } else {
255                 key.objectid = ino;
256                 key.offset = btrfs_ino(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         read_extent_buffer(leaf, name, name_ptr, name_len);
287         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         name[name_len] = '\0';
294 
295         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 };
305 

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