1 /* 2 * Copyright (C) 2007 Oracle. All rights reserved. 3 * 4 * This program is free software; you can redistribute it and/or 5 * modify it under the terms of the GNU General Public 6 * License v2 as published by the Free Software Foundation. 7 * 8 * This program is distributed in the hope that it will be useful, 9 * but WITHOUT ANY WARRANTY; without even the implied warranty of 10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 11 * General Public License for more details. 12 * 13 * You should have received a copy of the GNU General Public 14 * License along with this program; if not, write to the 15 * Free Software Foundation, Inc., 59 Temple Place - Suite 330, 16 * Boston, MA 021110-1307, USA. 17 */ 18 19 #include "ctree.h" 20 #include "transaction.h" 21 #include "disk-io.h" 22 #include "print-tree.h" 23 24 /* 25 * search forward for a root, starting with objectid 'search_start' 26 * if a root key is found, the objectid we find is filled into 'found_objectid' 27 * and 0 is returned. < 0 is returned on error, 1 if there is nothing 28 * left in the tree. 29 */ 30 int btrfs_search_root(struct btrfs_root *root, u64 search_start, 31 u64 *found_objectid) 32 { 33 struct btrfs_path *path; 34 struct btrfs_key search_key; 35 int ret; 36 37 root = root->fs_info->tree_root; 38 search_key.objectid = search_start; 39 search_key.type = (u8)-1; 40 search_key.offset = (u64)-1; 41 42 path = btrfs_alloc_path(); 43 BUG_ON(!path); 44 again: 45 ret = btrfs_search_slot(NULL, root, &search_key, path, 0, 0); 46 if (ret < 0) 47 goto out; 48 if (ret == 0) { 49 ret = 1; 50 goto out; 51 } 52 if (path->slots[0] >= btrfs_header_nritems(path->nodes[0])) { 53 ret = btrfs_next_leaf(root, path); 54 if (ret) 55 goto out; 56 } 57 btrfs_item_key_to_cpu(path->nodes[0], &search_key, path->slots[0]); 58 if (search_key.type != BTRFS_ROOT_ITEM_KEY) { 59 search_key.offset++; 60 btrfs_release_path(root, path); 61 goto again; 62 } 63 ret = 0; 64 *found_objectid = search_key.objectid; 65 66 out: 67 btrfs_free_path(path); 68 return ret; 69 } 70 71 /* 72 * lookup the root with the highest offset for a given objectid. The key we do 73 * find is copied into 'key'. If we find something return 0, otherwise 1, < 0 74 * on error. 75 */ 76 int btrfs_find_last_root(struct btrfs_root *root, u64 objectid, 77 struct btrfs_root_item *item, struct btrfs_key *key) 78 { 79 struct btrfs_path *path; 80 struct btrfs_key search_key; 81 struct btrfs_key found_key; 82 struct extent_buffer *l; 83 int ret; 84 int slot; 85 86 search_key.objectid = objectid; 87 search_key.type = BTRFS_ROOT_ITEM_KEY; 88 search_key.offset = (u64)-1; 89 90 path = btrfs_alloc_path(); 91 BUG_ON(!path); 92 ret = btrfs_search_slot(NULL, root, &search_key, path, 0, 0); 93 if (ret < 0) 94 goto out; 95 96 BUG_ON(ret == 0); 97 l = path->nodes[0]; 98 BUG_ON(path->slots[0] == 0); 99 slot = path->slots[0] - 1; 100 btrfs_item_key_to_cpu(l, &found_key, slot); 101 if (found_key.objectid != objectid) { 102 ret = 1; 103 goto out; 104 } 105 read_extent_buffer(l, item, btrfs_item_ptr_offset(l, slot), 106 sizeof(*item)); 107 memcpy(key, &found_key, sizeof(found_key)); 108 ret = 0; 109 out: 110 btrfs_free_path(path); 111 return ret; 112 } 113 114 /* 115 * copy the data in 'item' into the btree 116 */ 117 int btrfs_update_root(struct btrfs_trans_handle *trans, struct btrfs_root 118 *root, struct btrfs_key *key, struct btrfs_root_item 119 *item) 120 { 121 struct btrfs_path *path; 122 struct extent_buffer *l; 123 int ret; 124 int slot; 125 unsigned long ptr; 126 127 path = btrfs_alloc_path(); 128 BUG_ON(!path); 129 ret = btrfs_search_slot(trans, root, key, path, 0, 1); 130 if (ret < 0) 131 goto out; 132 133 if (ret != 0) { 134 btrfs_print_leaf(root, path->nodes[0]); 135 printk(KERN_CRIT "unable to update root key %llu %u %llu\n", 136 (unsigned long long)key->objectid, key->type, 137 (unsigned long long)key->offset); 138 BUG_ON(1); 139 } 140 141 l = path->nodes[0]; 142 slot = path->slots[0]; 143 ptr = btrfs_item_ptr_offset(l, slot); 144 write_extent_buffer(l, item, ptr, sizeof(*item)); 145 btrfs_mark_buffer_dirty(path->nodes[0]); 146 out: 147 btrfs_release_path(root, path); 148 btrfs_free_path(path); 149 return ret; 150 } 151 152 int btrfs_insert_root(struct btrfs_trans_handle *trans, struct btrfs_root 153 *root, struct btrfs_key *key, struct btrfs_root_item 154 *item) 155 { 156 int ret; 157 ret = btrfs_insert_item(trans, root, key, item, sizeof(*item)); 158 return ret; 159 } 160 161 /* 162 * at mount time we want to find all the old transaction snapshots that were in 163 * the process of being deleted if we crashed. This is any root item with an 164 * offset lower than the latest root. They need to be queued for deletion to 165 * finish what was happening when we crashed. 166 */ 167 int btrfs_find_dead_roots(struct btrfs_root *root, u64 objectid, 168 struct btrfs_root *latest) 169 { 170 struct btrfs_root *dead_root; 171 struct btrfs_item *item; 172 struct btrfs_root_item *ri; 173 struct btrfs_key key; 174 struct btrfs_key found_key; 175 struct btrfs_path *path; 176 int ret; 177 u32 nritems; 178 struct extent_buffer *leaf; 179 int slot; 180 181 key.objectid = objectid; 182 btrfs_set_key_type(&key, BTRFS_ROOT_ITEM_KEY); 183 key.offset = 0; 184 path = btrfs_alloc_path(); 185 if (!path) 186 return -ENOMEM; 187 188 again: 189 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0); 190 if (ret < 0) 191 goto err; 192 while (1) { 193 leaf = path->nodes[0]; 194 nritems = btrfs_header_nritems(leaf); 195 slot = path->slots[0]; 196 if (slot >= nritems) { 197 ret = btrfs_next_leaf(root, path); 198 if (ret) 199 break; 200 leaf = path->nodes[0]; 201 nritems = btrfs_header_nritems(leaf); 202 slot = path->slots[0]; 203 } 204 item = btrfs_item_nr(leaf, slot); 205 btrfs_item_key_to_cpu(leaf, &key, slot); 206 if (btrfs_key_type(&key) != BTRFS_ROOT_ITEM_KEY) 207 goto next; 208 209 if (key.objectid < objectid) 210 goto next; 211 212 if (key.objectid > objectid) 213 break; 214 215 ri = btrfs_item_ptr(leaf, slot, struct btrfs_root_item); 216 if (btrfs_disk_root_refs(leaf, ri) != 0) 217 goto next; 218 219 memcpy(&found_key, &key, sizeof(key)); 220 key.offset++; 221 btrfs_release_path(root, path); 222 dead_root = 223 btrfs_read_fs_root_no_radix(root->fs_info->tree_root, 224 &found_key); 225 if (IS_ERR(dead_root)) { 226 ret = PTR_ERR(dead_root); 227 goto err; 228 } 229 230 if (objectid == BTRFS_TREE_RELOC_OBJECTID) 231 ret = btrfs_add_dead_reloc_root(dead_root); 232 else 233 ret = btrfs_add_dead_root(dead_root, latest); 234 if (ret) 235 goto err; 236 goto again; 237 next: 238 slot++; 239 path->slots[0]++; 240 } 241 ret = 0; 242 err: 243 btrfs_free_path(path); 244 return ret; 245 } 246 247 /* drop the root item for 'key' from 'root' */ 248 int btrfs_del_root(struct btrfs_trans_handle *trans, struct btrfs_root *root, 249 struct btrfs_key *key) 250 { 251 struct btrfs_path *path; 252 int ret; 253 u32 refs; 254 struct btrfs_root_item *ri; 255 struct extent_buffer *leaf; 256 257 path = btrfs_alloc_path(); 258 BUG_ON(!path); 259 ret = btrfs_search_slot(trans, root, key, path, -1, 1); 260 if (ret < 0) 261 goto out; 262 263 BUG_ON(ret != 0); 264 leaf = path->nodes[0]; 265 ri = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_root_item); 266 267 refs = btrfs_disk_root_refs(leaf, ri); 268 BUG_ON(refs != 0); 269 ret = btrfs_del_item(trans, root, path); 270 out: 271 btrfs_release_path(root, path); 272 btrfs_free_path(path); 273 return ret; 274 } 275 276 #if 0 /* this will get used when snapshot deletion is implemented */ 277 int btrfs_del_root_ref(struct btrfs_trans_handle *trans, 278 struct btrfs_root *tree_root, 279 u64 root_id, u8 type, u64 ref_id) 280 { 281 struct btrfs_key key; 282 int ret; 283 struct btrfs_path *path; 284 285 path = btrfs_alloc_path(); 286 287 key.objectid = root_id; 288 key.type = type; 289 key.offset = ref_id; 290 291 ret = btrfs_search_slot(trans, tree_root, &key, path, -1, 1); 292 BUG_ON(ret); 293 294 ret = btrfs_del_item(trans, tree_root, path); 295 BUG_ON(ret); 296 297 btrfs_free_path(path); 298 return ret; 299 } 300 #endif 301 302 int btrfs_find_root_ref(struct btrfs_root *tree_root, 303 struct btrfs_path *path, 304 u64 root_id, u64 ref_id) 305 { 306 struct btrfs_key key; 307 int ret; 308 309 key.objectid = root_id; 310 key.type = BTRFS_ROOT_REF_KEY; 311 key.offset = ref_id; 312 313 ret = btrfs_search_slot(NULL, tree_root, &key, path, 0, 0); 314 return ret; 315 } 316 317 318 /* 319 * add a btrfs_root_ref item. type is either BTRFS_ROOT_REF_KEY 320 * or BTRFS_ROOT_BACKREF_KEY. 321 * 322 * The dirid, sequence, name and name_len refer to the directory entry 323 * that is referencing the root. 324 * 325 * For a forward ref, the root_id is the id of the tree referencing 326 * the root and ref_id is the id of the subvol or snapshot. 327 * 328 * For a back ref the root_id is the id of the subvol or snapshot and 329 * ref_id is the id of the tree referencing it. 330 */ 331 int btrfs_add_root_ref(struct btrfs_trans_handle *trans, 332 struct btrfs_root *tree_root, 333 u64 root_id, u8 type, u64 ref_id, 334 u64 dirid, u64 sequence, 335 const char *name, int name_len) 336 { 337 struct btrfs_key key; 338 int ret; 339 struct btrfs_path *path; 340 struct btrfs_root_ref *ref; 341 struct extent_buffer *leaf; 342 unsigned long ptr; 343 344 345 path = btrfs_alloc_path(); 346 347 key.objectid = root_id; 348 key.type = type; 349 key.offset = ref_id; 350 351 ret = btrfs_insert_empty_item(trans, tree_root, path, &key, 352 sizeof(*ref) + name_len); 353 BUG_ON(ret); 354 355 leaf = path->nodes[0]; 356 ref = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_root_ref); 357 btrfs_set_root_ref_dirid(leaf, ref, dirid); 358 btrfs_set_root_ref_sequence(leaf, ref, sequence); 359 btrfs_set_root_ref_name_len(leaf, ref, name_len); 360 ptr = (unsigned long)(ref + 1); 361 write_extent_buffer(leaf, name, ptr, name_len); 362 btrfs_mark_buffer_dirty(leaf); 363 364 btrfs_free_path(path); 365 return ret; 366 } 367