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