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