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