| 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 <linux/err.h> |
| 20 | #include <linux/uuid.h> |
| 21 | #include "ctree.h" |
| 22 | #include "transaction.h" |
| 23 | #include "disk-io.h" |
| 24 | #include "print-tree.h" |
| 25 | |
| 26 | /* |
| 27 | * Read a root item from the tree. In case we detect a root item smaller then |
| 28 | * sizeof(root_item), we know it's an old version of the root structure and |
| 29 | * initialize all new fields to zero. The same happens if we detect mismatching |
| 30 | * generation numbers as then we know the root was once mounted with an older |
| 31 | * kernel that was not aware of the root item structure change. |
| 32 | */ |
| 33 | static void btrfs_read_root_item(struct extent_buffer *eb, int slot, |
| 34 | struct btrfs_root_item *item) |
| 35 | { |
| 36 | uuid_le uuid; |
| 37 | int len; |
| 38 | int need_reset = 0; |
| 39 | |
| 40 | len = btrfs_item_size_nr(eb, slot); |
| 41 | read_extent_buffer(eb, item, btrfs_item_ptr_offset(eb, slot), |
| 42 | min_t(int, len, (int)sizeof(*item))); |
| 43 | if (len < sizeof(*item)) |
| 44 | need_reset = 1; |
| 45 | if (!need_reset && btrfs_root_generation(item) |
| 46 | != btrfs_root_generation_v2(item)) { |
| 47 | if (btrfs_root_generation_v2(item) != 0) { |
| 48 | btrfs_warn(eb->fs_info, |
| 49 | "mismatching " |
| 50 | "generation and generation_v2 " |
| 51 | "found in root item. This root " |
| 52 | "was probably mounted with an " |
| 53 | "older kernel. Resetting all " |
| 54 | "new fields."); |
| 55 | } |
| 56 | need_reset = 1; |
| 57 | } |
| 58 | if (need_reset) { |
| 59 | memset(&item->generation_v2, 0, |
| 60 | sizeof(*item) - offsetof(struct btrfs_root_item, |
| 61 | generation_v2)); |
| 62 | |
| 63 | uuid_le_gen(&uuid); |
| 64 | memcpy(item->uuid, uuid.b, BTRFS_UUID_SIZE); |
| 65 | } |
| 66 | } |
| 67 | |
| 68 | /* |
| 69 | * btrfs_find_root - lookup the root by the key. |
| 70 | * root: the root of the root tree |
| 71 | * search_key: the key to search |
| 72 | * path: the path we search |
| 73 | * root_item: the root item of the tree we look for |
| 74 | * root_key: the root key of the tree we look for |
| 75 | * |
| 76 | * If ->offset of 'search_key' is -1ULL, it means we are not sure the offset |
| 77 | * of the search key, just lookup the root with the highest offset for a |
| 78 | * given objectid. |
| 79 | * |
| 80 | * If we find something return 0, otherwise > 0, < 0 on error. |
| 81 | */ |
| 82 | int btrfs_find_root(struct btrfs_root *root, struct btrfs_key *search_key, |
| 83 | struct btrfs_path *path, struct btrfs_root_item *root_item, |
| 84 | struct btrfs_key *root_key) |
| 85 | { |
| 86 | struct btrfs_key found_key; |
| 87 | struct extent_buffer *l; |
| 88 | int ret; |
| 89 | int slot; |
| 90 | |
| 91 | ret = btrfs_search_slot(NULL, root, search_key, path, 0, 0); |
| 92 | if (ret < 0) |
| 93 | return ret; |
| 94 | |
| 95 | if (search_key->offset != -1ULL) { /* the search key is exact */ |
| 96 | if (ret > 0) |
| 97 | goto out; |
| 98 | } else { |
| 99 | BUG_ON(ret == 0); /* Logical error */ |
| 100 | if (path->slots[0] == 0) |
| 101 | goto out; |
| 102 | path->slots[0]--; |
| 103 | ret = 0; |
| 104 | } |
| 105 | |
| 106 | l = path->nodes[0]; |
| 107 | slot = path->slots[0]; |
| 108 | |
| 109 | btrfs_item_key_to_cpu(l, &found_key, slot); |
| 110 | if (found_key.objectid != search_key->objectid || |
| 111 | found_key.type != BTRFS_ROOT_ITEM_KEY) { |
| 112 | ret = 1; |
| 113 | goto out; |
| 114 | } |
| 115 | |
| 116 | if (root_item) |
| 117 | btrfs_read_root_item(l, slot, root_item); |
| 118 | if (root_key) |
| 119 | memcpy(root_key, &found_key, sizeof(found_key)); |
| 120 | out: |
| 121 | btrfs_release_path(path); |
| 122 | return ret; |
| 123 | } |
| 124 | |
| 125 | void btrfs_set_root_node(struct btrfs_root_item *item, |
| 126 | struct extent_buffer *node) |
| 127 | { |
| 128 | btrfs_set_root_bytenr(item, node->start); |
| 129 | btrfs_set_root_level(item, btrfs_header_level(node)); |
| 130 | btrfs_set_root_generation(item, btrfs_header_generation(node)); |
| 131 | } |
| 132 | |
| 133 | /* |
| 134 | * copy the data in 'item' into the btree |
| 135 | */ |
| 136 | int btrfs_update_root(struct btrfs_trans_handle *trans, struct btrfs_root |
| 137 | *root, struct btrfs_key *key, struct btrfs_root_item |
| 138 | *item) |
| 139 | { |
| 140 | struct btrfs_path *path; |
| 141 | struct extent_buffer *l; |
| 142 | int ret; |
| 143 | int slot; |
| 144 | unsigned long ptr; |
| 145 | u32 old_len; |
| 146 | |
| 147 | path = btrfs_alloc_path(); |
| 148 | if (!path) |
| 149 | return -ENOMEM; |
| 150 | |
| 151 | ret = btrfs_search_slot(trans, root, key, path, 0, 1); |
| 152 | if (ret < 0) { |
| 153 | btrfs_abort_transaction(trans, root, ret); |
| 154 | goto out; |
| 155 | } |
| 156 | |
| 157 | if (ret != 0) { |
| 158 | btrfs_print_leaf(root, path->nodes[0]); |
| 159 | btrfs_crit(root->fs_info, "unable to update root key %llu %u %llu", |
| 160 | key->objectid, key->type, key->offset); |
| 161 | BUG_ON(1); |
| 162 | } |
| 163 | |
| 164 | l = path->nodes[0]; |
| 165 | slot = path->slots[0]; |
| 166 | ptr = btrfs_item_ptr_offset(l, slot); |
| 167 | old_len = btrfs_item_size_nr(l, slot); |
| 168 | |
| 169 | /* |
| 170 | * If this is the first time we update the root item which originated |
| 171 | * from an older kernel, we need to enlarge the item size to make room |
| 172 | * for the added fields. |
| 173 | */ |
| 174 | if (old_len < sizeof(*item)) { |
| 175 | btrfs_release_path(path); |
| 176 | ret = btrfs_search_slot(trans, root, key, path, |
| 177 | -1, 1); |
| 178 | if (ret < 0) { |
| 179 | btrfs_abort_transaction(trans, root, ret); |
| 180 | goto out; |
| 181 | } |
| 182 | |
| 183 | ret = btrfs_del_item(trans, root, path); |
| 184 | if (ret < 0) { |
| 185 | btrfs_abort_transaction(trans, root, ret); |
| 186 | goto out; |
| 187 | } |
| 188 | btrfs_release_path(path); |
| 189 | ret = btrfs_insert_empty_item(trans, root, path, |
| 190 | key, sizeof(*item)); |
| 191 | if (ret < 0) { |
| 192 | btrfs_abort_transaction(trans, root, ret); |
| 193 | goto out; |
| 194 | } |
| 195 | l = path->nodes[0]; |
| 196 | slot = path->slots[0]; |
| 197 | ptr = btrfs_item_ptr_offset(l, slot); |
| 198 | } |
| 199 | |
| 200 | /* |
| 201 | * Update generation_v2 so at the next mount we know the new root |
| 202 | * fields are valid. |
| 203 | */ |
| 204 | btrfs_set_root_generation_v2(item, btrfs_root_generation(item)); |
| 205 | |
| 206 | write_extent_buffer(l, item, ptr, sizeof(*item)); |
| 207 | btrfs_mark_buffer_dirty(path->nodes[0]); |
| 208 | out: |
| 209 | btrfs_free_path(path); |
| 210 | return ret; |
| 211 | } |
| 212 | |
| 213 | int btrfs_insert_root(struct btrfs_trans_handle *trans, struct btrfs_root *root, |
| 214 | struct btrfs_key *key, struct btrfs_root_item *item) |
| 215 | { |
| 216 | /* |
| 217 | * Make sure generation v1 and v2 match. See update_root for details. |
| 218 | */ |
| 219 | btrfs_set_root_generation_v2(item, btrfs_root_generation(item)); |
| 220 | return btrfs_insert_item(trans, root, key, item, sizeof(*item)); |
| 221 | } |
| 222 | |
| 223 | int btrfs_find_orphan_roots(struct btrfs_root *tree_root) |
| 224 | { |
| 225 | struct extent_buffer *leaf; |
| 226 | struct btrfs_path *path; |
| 227 | struct btrfs_key key; |
| 228 | struct btrfs_key root_key; |
| 229 | struct btrfs_root *root; |
| 230 | int err = 0; |
| 231 | int ret; |
| 232 | bool can_recover = true; |
| 233 | |
| 234 | if (tree_root->fs_info->sb->s_flags & MS_RDONLY) |
| 235 | can_recover = false; |
| 236 | |
| 237 | path = btrfs_alloc_path(); |
| 238 | if (!path) |
| 239 | return -ENOMEM; |
| 240 | |
| 241 | key.objectid = BTRFS_ORPHAN_OBJECTID; |
| 242 | key.type = BTRFS_ORPHAN_ITEM_KEY; |
| 243 | key.offset = 0; |
| 244 | |
| 245 | root_key.type = BTRFS_ROOT_ITEM_KEY; |
| 246 | root_key.offset = (u64)-1; |
| 247 | |
| 248 | while (1) { |
| 249 | ret = btrfs_search_slot(NULL, tree_root, &key, path, 0, 0); |
| 250 | if (ret < 0) { |
| 251 | err = ret; |
| 252 | break; |
| 253 | } |
| 254 | |
| 255 | leaf = path->nodes[0]; |
| 256 | if (path->slots[0] >= btrfs_header_nritems(leaf)) { |
| 257 | ret = btrfs_next_leaf(tree_root, path); |
| 258 | if (ret < 0) |
| 259 | err = ret; |
| 260 | if (ret != 0) |
| 261 | break; |
| 262 | leaf = path->nodes[0]; |
| 263 | } |
| 264 | |
| 265 | btrfs_item_key_to_cpu(leaf, &key, path->slots[0]); |
| 266 | btrfs_release_path(path); |
| 267 | |
| 268 | if (key.objectid != BTRFS_ORPHAN_OBJECTID || |
| 269 | key.type != BTRFS_ORPHAN_ITEM_KEY) |
| 270 | break; |
| 271 | |
| 272 | root_key.objectid = key.offset; |
| 273 | key.offset++; |
| 274 | |
| 275 | root = btrfs_read_fs_root(tree_root, &root_key); |
| 276 | err = PTR_ERR_OR_ZERO(root); |
| 277 | if (err && err != -ENOENT) { |
| 278 | break; |
| 279 | } else if (err == -ENOENT) { |
| 280 | struct btrfs_trans_handle *trans; |
| 281 | |
| 282 | btrfs_release_path(path); |
| 283 | |
| 284 | trans = btrfs_join_transaction(tree_root); |
| 285 | if (IS_ERR(trans)) { |
| 286 | err = PTR_ERR(trans); |
| 287 | btrfs_handle_fs_error(tree_root->fs_info, err, |
| 288 | "Failed to start trans to delete " |
| 289 | "orphan item"); |
| 290 | break; |
| 291 | } |
| 292 | err = btrfs_del_orphan_item(trans, tree_root, |
| 293 | root_key.objectid); |
| 294 | btrfs_end_transaction(trans, tree_root); |
| 295 | if (err) { |
| 296 | btrfs_handle_fs_error(tree_root->fs_info, err, |
| 297 | "Failed to delete root orphan " |
| 298 | "item"); |
| 299 | break; |
| 300 | } |
| 301 | continue; |
| 302 | } |
| 303 | |
| 304 | err = btrfs_init_fs_root(root); |
| 305 | if (err) { |
| 306 | btrfs_free_fs_root(root); |
| 307 | break; |
| 308 | } |
| 309 | |
| 310 | set_bit(BTRFS_ROOT_ORPHAN_ITEM_INSERTED, &root->state); |
| 311 | |
| 312 | err = btrfs_insert_fs_root(root->fs_info, root); |
| 313 | /* |
| 314 | * The root might have been inserted already, as before we look |
| 315 | * for orphan roots, log replay might have happened, which |
| 316 | * triggers a transaction commit and qgroup accounting, which |
| 317 | * in turn reads and inserts fs roots while doing backref |
| 318 | * walking. |
| 319 | */ |
| 320 | if (err == -EEXIST) |
| 321 | err = 0; |
| 322 | if (err) { |
| 323 | btrfs_free_fs_root(root); |
| 324 | break; |
| 325 | } |
| 326 | |
| 327 | if (btrfs_root_refs(&root->root_item) == 0) |
| 328 | btrfs_add_dead_root(root); |
| 329 | } |
| 330 | |
| 331 | btrfs_free_path(path); |
| 332 | return err; |
| 333 | } |
| 334 | |
| 335 | /* drop the root item for 'key' from 'root' */ |
| 336 | int btrfs_del_root(struct btrfs_trans_handle *trans, struct btrfs_root *root, |
| 337 | struct btrfs_key *key) |
| 338 | { |
| 339 | struct btrfs_path *path; |
| 340 | int ret; |
| 341 | |
| 342 | path = btrfs_alloc_path(); |
| 343 | if (!path) |
| 344 | return -ENOMEM; |
| 345 | ret = btrfs_search_slot(trans, root, key, path, -1, 1); |
| 346 | if (ret < 0) |
| 347 | goto out; |
| 348 | |
| 349 | BUG_ON(ret != 0); |
| 350 | |
| 351 | ret = btrfs_del_item(trans, root, path); |
| 352 | out: |
| 353 | btrfs_free_path(path); |
| 354 | return ret; |
| 355 | } |
| 356 | |
| 357 | int btrfs_del_root_ref(struct btrfs_trans_handle *trans, |
| 358 | struct btrfs_root *tree_root, |
| 359 | u64 root_id, u64 ref_id, u64 dirid, u64 *sequence, |
| 360 | const char *name, int name_len) |
| 361 | |
| 362 | { |
| 363 | struct btrfs_path *path; |
| 364 | struct btrfs_root_ref *ref; |
| 365 | struct extent_buffer *leaf; |
| 366 | struct btrfs_key key; |
| 367 | unsigned long ptr; |
| 368 | int err = 0; |
| 369 | int ret; |
| 370 | |
| 371 | path = btrfs_alloc_path(); |
| 372 | if (!path) |
| 373 | return -ENOMEM; |
| 374 | |
| 375 | key.objectid = root_id; |
| 376 | key.type = BTRFS_ROOT_BACKREF_KEY; |
| 377 | key.offset = ref_id; |
| 378 | again: |
| 379 | ret = btrfs_search_slot(trans, tree_root, &key, path, -1, 1); |
| 380 | BUG_ON(ret < 0); |
| 381 | if (ret == 0) { |
| 382 | leaf = path->nodes[0]; |
| 383 | ref = btrfs_item_ptr(leaf, path->slots[0], |
| 384 | struct btrfs_root_ref); |
| 385 | |
| 386 | WARN_ON(btrfs_root_ref_dirid(leaf, ref) != dirid); |
| 387 | WARN_ON(btrfs_root_ref_name_len(leaf, ref) != name_len); |
| 388 | ptr = (unsigned long)(ref + 1); |
| 389 | WARN_ON(memcmp_extent_buffer(leaf, name, ptr, name_len)); |
| 390 | *sequence = btrfs_root_ref_sequence(leaf, ref); |
| 391 | |
| 392 | ret = btrfs_del_item(trans, tree_root, path); |
| 393 | if (ret) { |
| 394 | err = ret; |
| 395 | goto out; |
| 396 | } |
| 397 | } else |
| 398 | err = -ENOENT; |
| 399 | |
| 400 | if (key.type == BTRFS_ROOT_BACKREF_KEY) { |
| 401 | btrfs_release_path(path); |
| 402 | key.objectid = ref_id; |
| 403 | key.type = BTRFS_ROOT_REF_KEY; |
| 404 | key.offset = root_id; |
| 405 | goto again; |
| 406 | } |
| 407 | |
| 408 | out: |
| 409 | btrfs_free_path(path); |
| 410 | return err; |
| 411 | } |
| 412 | |
| 413 | /* |
| 414 | * add a btrfs_root_ref item. type is either BTRFS_ROOT_REF_KEY |
| 415 | * or BTRFS_ROOT_BACKREF_KEY. |
| 416 | * |
| 417 | * The dirid, sequence, name and name_len refer to the directory entry |
| 418 | * that is referencing the root. |
| 419 | * |
| 420 | * For a forward ref, the root_id is the id of the tree referencing |
| 421 | * the root and ref_id is the id of the subvol or snapshot. |
| 422 | * |
| 423 | * For a back ref the root_id is the id of the subvol or snapshot and |
| 424 | * ref_id is the id of the tree referencing it. |
| 425 | * |
| 426 | * Will return 0, -ENOMEM, or anything from the CoW path |
| 427 | */ |
| 428 | int btrfs_add_root_ref(struct btrfs_trans_handle *trans, |
| 429 | struct btrfs_root *tree_root, |
| 430 | u64 root_id, u64 ref_id, u64 dirid, u64 sequence, |
| 431 | const char *name, int name_len) |
| 432 | { |
| 433 | struct btrfs_key key; |
| 434 | int ret; |
| 435 | struct btrfs_path *path; |
| 436 | struct btrfs_root_ref *ref; |
| 437 | struct extent_buffer *leaf; |
| 438 | unsigned long ptr; |
| 439 | |
| 440 | path = btrfs_alloc_path(); |
| 441 | if (!path) |
| 442 | return -ENOMEM; |
| 443 | |
| 444 | key.objectid = root_id; |
| 445 | key.type = BTRFS_ROOT_BACKREF_KEY; |
| 446 | key.offset = ref_id; |
| 447 | again: |
| 448 | ret = btrfs_insert_empty_item(trans, tree_root, path, &key, |
| 449 | sizeof(*ref) + name_len); |
| 450 | if (ret) { |
| 451 | btrfs_abort_transaction(trans, tree_root, ret); |
| 452 | btrfs_free_path(path); |
| 453 | return ret; |
| 454 | } |
| 455 | |
| 456 | leaf = path->nodes[0]; |
| 457 | ref = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_root_ref); |
| 458 | btrfs_set_root_ref_dirid(leaf, ref, dirid); |
| 459 | btrfs_set_root_ref_sequence(leaf, ref, sequence); |
| 460 | btrfs_set_root_ref_name_len(leaf, ref, name_len); |
| 461 | ptr = (unsigned long)(ref + 1); |
| 462 | write_extent_buffer(leaf, name, ptr, name_len); |
| 463 | btrfs_mark_buffer_dirty(leaf); |
| 464 | |
| 465 | if (key.type == BTRFS_ROOT_BACKREF_KEY) { |
| 466 | btrfs_release_path(path); |
| 467 | key.objectid = ref_id; |
| 468 | key.type = BTRFS_ROOT_REF_KEY; |
| 469 | key.offset = root_id; |
| 470 | goto again; |
| 471 | } |
| 472 | |
| 473 | btrfs_free_path(path); |
| 474 | return 0; |
| 475 | } |
| 476 | |
| 477 | /* |
| 478 | * Old btrfs forgets to init root_item->flags and root_item->byte_limit |
| 479 | * for subvolumes. To work around this problem, we steal a bit from |
| 480 | * root_item->inode_item->flags, and use it to indicate if those fields |
| 481 | * have been properly initialized. |
| 482 | */ |
| 483 | void btrfs_check_and_init_root_item(struct btrfs_root_item *root_item) |
| 484 | { |
| 485 | u64 inode_flags = btrfs_stack_inode_flags(&root_item->inode); |
| 486 | |
| 487 | if (!(inode_flags & BTRFS_INODE_ROOT_ITEM_INIT)) { |
| 488 | inode_flags |= BTRFS_INODE_ROOT_ITEM_INIT; |
| 489 | btrfs_set_stack_inode_flags(&root_item->inode, inode_flags); |
| 490 | btrfs_set_root_flags(root_item, 0); |
| 491 | btrfs_set_root_limit(root_item, 0); |
| 492 | } |
| 493 | } |
| 494 | |
| 495 | void btrfs_update_root_times(struct btrfs_trans_handle *trans, |
| 496 | struct btrfs_root *root) |
| 497 | { |
| 498 | struct btrfs_root_item *item = &root->root_item; |
| 499 | struct timespec ct = current_fs_time(root->fs_info->sb); |
| 500 | |
| 501 | spin_lock(&root->root_item_lock); |
| 502 | btrfs_set_root_ctransid(item, trans->transid); |
| 503 | btrfs_set_stack_timespec_sec(&item->ctime, ct.tv_sec); |
| 504 | btrfs_set_stack_timespec_nsec(&item->ctime, ct.tv_nsec); |
| 505 | spin_unlock(&root->root_item_lock); |
| 506 | } |