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 if (path->slots[0] == 0) { 98 ret = 1; 99 goto out; 100 } 101 l = path->nodes[0]; 102 slot = path->slots[0] - 1; 103 btrfs_item_key_to_cpu(l, &found_key, slot); 104 if (found_key.objectid != objectid || 105 found_key.type != BTRFS_ROOT_ITEM_KEY) { 106 ret = 1; 107 goto out; 108 } 109 if (item) 110 read_extent_buffer(l, item, btrfs_item_ptr_offset(l, slot), 111 sizeof(*item)); 112 if (key) 113 memcpy(key, &found_key, sizeof(found_key)); 114 ret = 0; 115 out: 116 btrfs_free_path(path); 117 return ret; 118 } 119 120 int btrfs_set_root_node(struct btrfs_root_item *item, 121 struct extent_buffer *node) 122 { 123 btrfs_set_root_bytenr(item, node->start); 124 btrfs_set_root_level(item, btrfs_header_level(node)); 125 btrfs_set_root_generation(item, btrfs_header_generation(node)); 126 return 0; 127 } 128 129 /* 130 * copy the data in 'item' into the btree 131 */ 132 int btrfs_update_root(struct btrfs_trans_handle *trans, struct btrfs_root 133 *root, struct btrfs_key *key, struct btrfs_root_item 134 *item) 135 { 136 struct btrfs_path *path; 137 struct extent_buffer *l; 138 int ret; 139 int slot; 140 unsigned long ptr; 141 142 path = btrfs_alloc_path(); 143 BUG_ON(!path); 144 ret = btrfs_search_slot(trans, root, key, path, 0, 1); 145 if (ret < 0) 146 goto out; 147 148 if (ret != 0) { 149 btrfs_print_leaf(root, path->nodes[0]); 150 printk(KERN_CRIT "unable to update root key %llu %u %llu\n", 151 (unsigned long long)key->objectid, key->type, 152 (unsigned long long)key->offset); 153 BUG_ON(1); 154 } 155 156 l = path->nodes[0]; 157 slot = path->slots[0]; 158 ptr = btrfs_item_ptr_offset(l, slot); 159 write_extent_buffer(l, item, ptr, sizeof(*item)); 160 btrfs_mark_buffer_dirty(path->nodes[0]); 161 out: 162 btrfs_free_path(path); 163 return ret; 164 } 165 166 int btrfs_insert_root(struct btrfs_trans_handle *trans, struct btrfs_root 167 *root, struct btrfs_key *key, struct btrfs_root_item 168 *item) 169 { 170 int ret; 171 ret = btrfs_insert_item(trans, root, key, item, sizeof(*item)); 172 return ret; 173 } 174 175 /* 176 * at mount time we want to find all the old transaction snapshots that were in 177 * the process of being deleted if we crashed. This is any root item with an 178 * offset lower than the latest root. They need to be queued for deletion to 179 * finish what was happening when we crashed. 180 */ 181 int btrfs_find_dead_roots(struct btrfs_root *root, u64 objectid) 182 { 183 struct btrfs_root *dead_root; 184 struct btrfs_root_item *ri; 185 struct btrfs_key key; 186 struct btrfs_key found_key; 187 struct btrfs_path *path; 188 int ret; 189 u32 nritems; 190 struct extent_buffer *leaf; 191 int slot; 192 193 key.objectid = objectid; 194 btrfs_set_key_type(&key, BTRFS_ROOT_ITEM_KEY); 195 key.offset = 0; 196 path = btrfs_alloc_path(); 197 if (!path) 198 return -ENOMEM; 199 200 again: 201 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0); 202 if (ret < 0) 203 goto err; 204 while (1) { 205 leaf = path->nodes[0]; 206 nritems = btrfs_header_nritems(leaf); 207 slot = path->slots[0]; 208 if (slot >= nritems) { 209 ret = btrfs_next_leaf(root, path); 210 if (ret) 211 break; 212 leaf = path->nodes[0]; 213 nritems = btrfs_header_nritems(leaf); 214 slot = path->slots[0]; 215 } 216 btrfs_item_key_to_cpu(leaf, &key, slot); 217 if (btrfs_key_type(&key) != BTRFS_ROOT_ITEM_KEY) 218 goto next; 219 220 if (key.objectid < objectid) 221 goto next; 222 223 if (key.objectid > objectid) 224 break; 225 226 ri = btrfs_item_ptr(leaf, slot, struct btrfs_root_item); 227 if (btrfs_disk_root_refs(leaf, ri) != 0) 228 goto next; 229 230 memcpy(&found_key, &key, sizeof(key)); 231 key.offset++; 232 btrfs_release_path(root, path); 233 dead_root = 234 btrfs_read_fs_root_no_radix(root->fs_info->tree_root, 235 &found_key); 236 if (IS_ERR(dead_root)) { 237 ret = PTR_ERR(dead_root); 238 goto err; 239 } 240 241 ret = btrfs_add_dead_root(dead_root); 242 if (ret) 243 goto err; 244 goto again; 245 next: 246 slot++; 247 path->slots[0]++; 248 } 249 ret = 0; 250 err: 251 btrfs_free_path(path); 252 return ret; 253 } 254 255 int btrfs_find_orphan_roots(struct btrfs_root *tree_root) 256 { 257 struct extent_buffer *leaf; 258 struct btrfs_path *path; 259 struct btrfs_key key; 260 struct btrfs_key root_key; 261 struct btrfs_root *root; 262 int err = 0; 263 int ret; 264 265 path = btrfs_alloc_path(); 266 if (!path) 267 return -ENOMEM; 268 269 key.objectid = BTRFS_ORPHAN_OBJECTID; 270 key.type = BTRFS_ORPHAN_ITEM_KEY; 271 key.offset = 0; 272 273 root_key.type = BTRFS_ROOT_ITEM_KEY; 274 root_key.offset = (u64)-1; 275 276 while (1) { 277 ret = btrfs_search_slot(NULL, tree_root, &key, path, 0, 0); 278 if (ret < 0) { 279 err = ret; 280 break; 281 } 282 283 leaf = path->nodes[0]; 284 if (path->slots[0] >= btrfs_header_nritems(leaf)) { 285 ret = btrfs_next_leaf(tree_root, path); 286 if (ret < 0) 287 err = ret; 288 if (ret != 0) 289 break; 290 leaf = path->nodes[0]; 291 } 292 293 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]); 294 btrfs_release_path(tree_root, path); 295 296 if (key.objectid != BTRFS_ORPHAN_OBJECTID || 297 key.type != BTRFS_ORPHAN_ITEM_KEY) 298 break; 299 300 root_key.objectid = key.offset; 301 key.offset++; 302 303 root = btrfs_read_fs_root_no_name(tree_root->fs_info, 304 &root_key); 305 if (!IS_ERR(root)) 306 continue; 307 308 ret = PTR_ERR(root); 309 if (ret != -ENOENT) { 310 err = ret; 311 break; 312 } 313 314 ret = btrfs_find_dead_roots(tree_root, root_key.objectid); 315 if (ret) { 316 err = ret; 317 break; 318 } 319 } 320 321 btrfs_free_path(path); 322 return err; 323 } 324 325 /* drop the root item for 'key' from 'root' */ 326 int btrfs_del_root(struct btrfs_trans_handle *trans, struct btrfs_root *root, 327 struct btrfs_key *key) 328 { 329 struct btrfs_path *path; 330 int ret; 331 struct btrfs_root_item *ri; 332 struct extent_buffer *leaf; 333 334 path = btrfs_alloc_path(); 335 BUG_ON(!path); 336 ret = btrfs_search_slot(trans, root, key, path, -1, 1); 337 if (ret < 0) 338 goto out; 339 340 BUG_ON(ret != 0); 341 leaf = path->nodes[0]; 342 ri = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_root_item); 343 344 ret = btrfs_del_item(trans, root, path); 345 out: 346 btrfs_free_path(path); 347 return ret; 348 } 349 350 int btrfs_del_root_ref(struct btrfs_trans_handle *trans, 351 struct btrfs_root *tree_root, 352 u64 root_id, u64 ref_id, u64 dirid, u64 *sequence, 353 const char *name, int name_len) 354 355 { 356 struct btrfs_path *path; 357 struct btrfs_root_ref *ref; 358 struct extent_buffer *leaf; 359 struct btrfs_key key; 360 unsigned long ptr; 361 int err = 0; 362 int ret; 363 364 path = btrfs_alloc_path(); 365 if (!path) 366 return -ENOMEM; 367 368 key.objectid = root_id; 369 key.type = BTRFS_ROOT_BACKREF_KEY; 370 key.offset = ref_id; 371 again: 372 ret = btrfs_search_slot(trans, tree_root, &key, path, -1, 1); 373 BUG_ON(ret < 0); 374 if (ret == 0) { 375 leaf = path->nodes[0]; 376 ref = btrfs_item_ptr(leaf, path->slots[0], 377 struct btrfs_root_ref); 378 379 WARN_ON(btrfs_root_ref_dirid(leaf, ref) != dirid); 380 WARN_ON(btrfs_root_ref_name_len(leaf, ref) != name_len); 381 ptr = (unsigned long)(ref + 1); 382 WARN_ON(memcmp_extent_buffer(leaf, name, ptr, name_len)); 383 *sequence = btrfs_root_ref_sequence(leaf, ref); 384 385 ret = btrfs_del_item(trans, tree_root, path); 386 BUG_ON(ret); 387 } else 388 err = -ENOENT; 389 390 if (key.type == BTRFS_ROOT_BACKREF_KEY) { 391 btrfs_release_path(tree_root, path); 392 key.objectid = ref_id; 393 key.type = BTRFS_ROOT_REF_KEY; 394 key.offset = root_id; 395 goto again; 396 } 397 398 btrfs_free_path(path); 399 return err; 400 } 401 402 int btrfs_find_root_ref(struct btrfs_root *tree_root, 403 struct btrfs_path *path, 404 u64 root_id, u64 ref_id) 405 { 406 struct btrfs_key key; 407 int ret; 408 409 key.objectid = root_id; 410 key.type = BTRFS_ROOT_REF_KEY; 411 key.offset = ref_id; 412 413 ret = btrfs_search_slot(NULL, tree_root, &key, path, 0, 0); 414 return ret; 415 } 416 417 /* 418 * add a btrfs_root_ref item. type is either BTRFS_ROOT_REF_KEY 419 * or BTRFS_ROOT_BACKREF_KEY. 420 * 421 * The dirid, sequence, name and name_len refer to the directory entry 422 * that is referencing the root. 423 * 424 * For a forward ref, the root_id is the id of the tree referencing 425 * the root and ref_id is the id of the subvol or snapshot. 426 * 427 * For a back ref the root_id is the id of the subvol or snapshot and 428 * ref_id is the id of the tree referencing it. 429 */ 430 int btrfs_add_root_ref(struct btrfs_trans_handle *trans, 431 struct btrfs_root *tree_root, 432 u64 root_id, u64 ref_id, u64 dirid, u64 sequence, 433 const char *name, int name_len) 434 { 435 struct btrfs_key key; 436 int ret; 437 struct btrfs_path *path; 438 struct btrfs_root_ref *ref; 439 struct extent_buffer *leaf; 440 unsigned long ptr; 441 442 path = btrfs_alloc_path(); 443 if (!path) 444 return -ENOMEM; 445 446 key.objectid = root_id; 447 key.type = BTRFS_ROOT_BACKREF_KEY; 448 key.offset = ref_id; 449 again: 450 ret = btrfs_insert_empty_item(trans, tree_root, path, &key, 451 sizeof(*ref) + name_len); 452 BUG_ON(ret); 453 454 leaf = path->nodes[0]; 455 ref = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_root_ref); 456 btrfs_set_root_ref_dirid(leaf, ref, dirid); 457 btrfs_set_root_ref_sequence(leaf, ref, sequence); 458 btrfs_set_root_ref_name_len(leaf, ref, name_len); 459 ptr = (unsigned long)(ref + 1); 460 write_extent_buffer(leaf, name, ptr, name_len); 461 btrfs_mark_buffer_dirty(leaf); 462 463 if (key.type == BTRFS_ROOT_BACKREF_KEY) { 464 btrfs_release_path(tree_root, path); 465 key.objectid = ref_id; 466 key.type = BTRFS_ROOT_REF_KEY; 467 key.offset = root_id; 468 goto again; 469 } 470 471 btrfs_free_path(path); 472 return 0; 473 } 474