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 = inode->i_ino; 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 (dir->i_ino == 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 = dir->i_ino; 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; 247 248 if (!dir || !inode) 249 return -EINVAL; 250 251 if (!S_ISDIR(dir->i_mode)) 252 return -EINVAL; 253 254 path = btrfs_alloc_path(); 255 if (!path) 256 return -ENOMEM; 257 path->leave_spinning = 1; 258 259 if (inode->i_ino == BTRFS_FIRST_FREE_OBJECTID) { 260 key.objectid = BTRFS_I(inode)->root->root_key.objectid; 261 key.type = BTRFS_ROOT_BACKREF_KEY; 262 key.offset = (u64)-1; 263 root = root->fs_info->tree_root; 264 } else { 265 key.objectid = inode->i_ino; 266 key.offset = dir->i_ino; 267 key.type = BTRFS_INODE_REF_KEY; 268 } 269 270 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0); 271 if (ret < 0) { 272 btrfs_free_path(path); 273 return ret; 274 } else if (ret > 0) { 275 if (inode->i_ino == BTRFS_FIRST_FREE_OBJECTID) { 276 path->slots[0]--; 277 } else { 278 btrfs_free_path(path); 279 return -ENOENT; 280 } 281 } 282 leaf = path->nodes[0]; 283 284 if (inode->i_ino == BTRFS_FIRST_FREE_OBJECTID) { 285 rref = btrfs_item_ptr(leaf, path->slots[0], 286 struct btrfs_root_ref); 287 name_ptr = (unsigned long)(rref + 1); 288 name_len = btrfs_root_ref_name_len(leaf, rref); 289 } else { 290 iref = btrfs_item_ptr(leaf, path->slots[0], 291 struct btrfs_inode_ref); 292 name_ptr = (unsigned long)(iref + 1); 293 name_len = btrfs_inode_ref_name_len(leaf, iref); 294 } 295 296 read_extent_buffer(leaf, name, name_ptr, name_len); 297 btrfs_free_path(path); 298 299 /* 300 * have to add the null termination to make sure that reconnect_path 301 * gets the right len for strlen 302 */ 303 name[name_len] = '\0'; 304 305 return 0; 306 } 307 308 const struct export_operations btrfs_export_ops = { 309 .encode_fh = btrfs_encode_fh, 310 .fh_to_dentry = btrfs_fh_to_dentry, 311 .fh_to_parent = btrfs_fh_to_parent, 312 .get_parent = btrfs_get_parent, 313 .get_name = btrfs_get_name, 314 }; 315