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