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