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/fs.h> 20 #include <linux/slab.h> 21 #include <linux/sched.h> 22 #include <linux/writeback.h> 23 #include <linux/pagemap.h> 24 #include <linux/blkdev.h> 25 #include <linux/uuid.h> 26 #include "ctree.h" 27 #include "disk-io.h" 28 #include "transaction.h" 29 #include "locking.h" 30 #include "tree-log.h" 31 #include "inode-map.h" 32 #include "volumes.h" 33 #include "dev-replace.h" 34 #include "qgroup.h" 35 36 #define BTRFS_ROOT_TRANS_TAG 0 37 38 static const unsigned int btrfs_blocked_trans_types[TRANS_STATE_MAX] = { 39 [TRANS_STATE_RUNNING] = 0U, 40 [TRANS_STATE_BLOCKED] = (__TRANS_USERSPACE | 41 __TRANS_START), 42 [TRANS_STATE_COMMIT_START] = (__TRANS_USERSPACE | 43 __TRANS_START | 44 __TRANS_ATTACH), 45 [TRANS_STATE_COMMIT_DOING] = (__TRANS_USERSPACE | 46 __TRANS_START | 47 __TRANS_ATTACH | 48 __TRANS_JOIN), 49 [TRANS_STATE_UNBLOCKED] = (__TRANS_USERSPACE | 50 __TRANS_START | 51 __TRANS_ATTACH | 52 __TRANS_JOIN | 53 __TRANS_JOIN_NOLOCK), 54 [TRANS_STATE_COMPLETED] = (__TRANS_USERSPACE | 55 __TRANS_START | 56 __TRANS_ATTACH | 57 __TRANS_JOIN | 58 __TRANS_JOIN_NOLOCK), 59 }; 60 61 void btrfs_put_transaction(struct btrfs_transaction *transaction) 62 { 63 WARN_ON(atomic_read(&transaction->use_count) == 0); 64 if (atomic_dec_and_test(&transaction->use_count)) { 65 BUG_ON(!list_empty(&transaction->list)); 66 WARN_ON(!RB_EMPTY_ROOT(&transaction->delayed_refs.href_root)); 67 if (transaction->delayed_refs.pending_csums) 68 printk(KERN_ERR "pending csums is %llu\n", 69 transaction->delayed_refs.pending_csums); 70 while (!list_empty(&transaction->pending_chunks)) { 71 struct extent_map *em; 72 73 em = list_first_entry(&transaction->pending_chunks, 74 struct extent_map, list); 75 list_del_init(&em->list); 76 free_extent_map(em); 77 } 78 /* 79 * If any block groups are found in ->deleted_bgs then it's 80 * because the transaction was aborted and a commit did not 81 * happen (things failed before writing the new superblock 82 * and calling btrfs_finish_extent_commit()), so we can not 83 * discard the physical locations of the block groups. 84 */ 85 while (!list_empty(&transaction->deleted_bgs)) { 86 struct btrfs_block_group_cache *cache; 87 88 cache = list_first_entry(&transaction->deleted_bgs, 89 struct btrfs_block_group_cache, 90 bg_list); 91 list_del_init(&cache->bg_list); 92 btrfs_put_block_group_trimming(cache); 93 btrfs_put_block_group(cache); 94 } 95 kmem_cache_free(btrfs_transaction_cachep, transaction); 96 } 97 } 98 99 static void clear_btree_io_tree(struct extent_io_tree *tree) 100 { 101 spin_lock(&tree->lock); 102 /* 103 * Do a single barrier for the waitqueue_active check here, the state 104 * of the waitqueue should not change once clear_btree_io_tree is 105 * called. 106 */ 107 smp_mb(); 108 while (!RB_EMPTY_ROOT(&tree->state)) { 109 struct rb_node *node; 110 struct extent_state *state; 111 112 node = rb_first(&tree->state); 113 state = rb_entry(node, struct extent_state, rb_node); 114 rb_erase(&state->rb_node, &tree->state); 115 RB_CLEAR_NODE(&state->rb_node); 116 /* 117 * btree io trees aren't supposed to have tasks waiting for 118 * changes in the flags of extent states ever. 119 */ 120 ASSERT(!waitqueue_active(&state->wq)); 121 free_extent_state(state); 122 123 cond_resched_lock(&tree->lock); 124 } 125 spin_unlock(&tree->lock); 126 } 127 128 static noinline void switch_commit_roots(struct btrfs_transaction *trans, 129 struct btrfs_fs_info *fs_info) 130 { 131 struct btrfs_root *root, *tmp; 132 133 down_write(&fs_info->commit_root_sem); 134 list_for_each_entry_safe(root, tmp, &trans->switch_commits, 135 dirty_list) { 136 list_del_init(&root->dirty_list); 137 free_extent_buffer(root->commit_root); 138 root->commit_root = btrfs_root_node(root); 139 if (is_fstree(root->objectid)) 140 btrfs_unpin_free_ino(root); 141 clear_btree_io_tree(&root->dirty_log_pages); 142 } 143 144 /* We can free old roots now. */ 145 spin_lock(&trans->dropped_roots_lock); 146 while (!list_empty(&trans->dropped_roots)) { 147 root = list_first_entry(&trans->dropped_roots, 148 struct btrfs_root, root_list); 149 list_del_init(&root->root_list); 150 spin_unlock(&trans->dropped_roots_lock); 151 btrfs_drop_and_free_fs_root(fs_info, root); 152 spin_lock(&trans->dropped_roots_lock); 153 } 154 spin_unlock(&trans->dropped_roots_lock); 155 up_write(&fs_info->commit_root_sem); 156 } 157 158 static inline void extwriter_counter_inc(struct btrfs_transaction *trans, 159 unsigned int type) 160 { 161 if (type & TRANS_EXTWRITERS) 162 atomic_inc(&trans->num_extwriters); 163 } 164 165 static inline void extwriter_counter_dec(struct btrfs_transaction *trans, 166 unsigned int type) 167 { 168 if (type & TRANS_EXTWRITERS) 169 atomic_dec(&trans->num_extwriters); 170 } 171 172 static inline void extwriter_counter_init(struct btrfs_transaction *trans, 173 unsigned int type) 174 { 175 atomic_set(&trans->num_extwriters, ((type & TRANS_EXTWRITERS) ? 1 : 0)); 176 } 177 178 static inline int extwriter_counter_read(struct btrfs_transaction *trans) 179 { 180 return atomic_read(&trans->num_extwriters); 181 } 182 183 /* 184 * either allocate a new transaction or hop into the existing one 185 */ 186 static noinline int join_transaction(struct btrfs_root *root, unsigned int type) 187 { 188 struct btrfs_transaction *cur_trans; 189 struct btrfs_fs_info *fs_info = root->fs_info; 190 191 spin_lock(&fs_info->trans_lock); 192 loop: 193 /* The file system has been taken offline. No new transactions. */ 194 if (test_bit(BTRFS_FS_STATE_ERROR, &fs_info->fs_state)) { 195 spin_unlock(&fs_info->trans_lock); 196 return -EROFS; 197 } 198 199 cur_trans = fs_info->running_transaction; 200 if (cur_trans) { 201 if (cur_trans->aborted) { 202 spin_unlock(&fs_info->trans_lock); 203 return cur_trans->aborted; 204 } 205 if (btrfs_blocked_trans_types[cur_trans->state] & type) { 206 spin_unlock(&fs_info->trans_lock); 207 return -EBUSY; 208 } 209 atomic_inc(&cur_trans->use_count); 210 atomic_inc(&cur_trans->num_writers); 211 extwriter_counter_inc(cur_trans, type); 212 spin_unlock(&fs_info->trans_lock); 213 return 0; 214 } 215 spin_unlock(&fs_info->trans_lock); 216 217 /* 218 * If we are ATTACH, we just want to catch the current transaction, 219 * and commit it. If there is no transaction, just return ENOENT. 220 */ 221 if (type == TRANS_ATTACH) 222 return -ENOENT; 223 224 /* 225 * JOIN_NOLOCK only happens during the transaction commit, so 226 * it is impossible that ->running_transaction is NULL 227 */ 228 BUG_ON(type == TRANS_JOIN_NOLOCK); 229 230 cur_trans = kmem_cache_alloc(btrfs_transaction_cachep, GFP_NOFS); 231 if (!cur_trans) 232 return -ENOMEM; 233 234 spin_lock(&fs_info->trans_lock); 235 if (fs_info->running_transaction) { 236 /* 237 * someone started a transaction after we unlocked. Make sure 238 * to redo the checks above 239 */ 240 kmem_cache_free(btrfs_transaction_cachep, cur_trans); 241 goto loop; 242 } else if (test_bit(BTRFS_FS_STATE_ERROR, &fs_info->fs_state)) { 243 spin_unlock(&fs_info->trans_lock); 244 kmem_cache_free(btrfs_transaction_cachep, cur_trans); 245 return -EROFS; 246 } 247 248 atomic_set(&cur_trans->num_writers, 1); 249 extwriter_counter_init(cur_trans, type); 250 init_waitqueue_head(&cur_trans->writer_wait); 251 init_waitqueue_head(&cur_trans->commit_wait); 252 init_waitqueue_head(&cur_trans->pending_wait); 253 cur_trans->state = TRANS_STATE_RUNNING; 254 /* 255 * One for this trans handle, one so it will live on until we 256 * commit the transaction. 257 */ 258 atomic_set(&cur_trans->use_count, 2); 259 atomic_set(&cur_trans->pending_ordered, 0); 260 cur_trans->flags = 0; 261 cur_trans->start_time = get_seconds(); 262 263 memset(&cur_trans->delayed_refs, 0, sizeof(cur_trans->delayed_refs)); 264 265 cur_trans->delayed_refs.href_root = RB_ROOT; 266 cur_trans->delayed_refs.dirty_extent_root = RB_ROOT; 267 atomic_set(&cur_trans->delayed_refs.num_entries, 0); 268 269 /* 270 * although the tree mod log is per file system and not per transaction, 271 * the log must never go across transaction boundaries. 272 */ 273 smp_mb(); 274 if (!list_empty(&fs_info->tree_mod_seq_list)) 275 WARN(1, KERN_ERR "BTRFS: tree_mod_seq_list not empty when " 276 "creating a fresh transaction\n"); 277 if (!RB_EMPTY_ROOT(&fs_info->tree_mod_log)) 278 WARN(1, KERN_ERR "BTRFS: tree_mod_log rb tree not empty when " 279 "creating a fresh transaction\n"); 280 atomic64_set(&fs_info->tree_mod_seq, 0); 281 282 spin_lock_init(&cur_trans->delayed_refs.lock); 283 284 INIT_LIST_HEAD(&cur_trans->pending_snapshots); 285 INIT_LIST_HEAD(&cur_trans->pending_chunks); 286 INIT_LIST_HEAD(&cur_trans->switch_commits); 287 INIT_LIST_HEAD(&cur_trans->dirty_bgs); 288 INIT_LIST_HEAD(&cur_trans->io_bgs); 289 INIT_LIST_HEAD(&cur_trans->dropped_roots); 290 mutex_init(&cur_trans->cache_write_mutex); 291 cur_trans->num_dirty_bgs = 0; 292 spin_lock_init(&cur_trans->dirty_bgs_lock); 293 INIT_LIST_HEAD(&cur_trans->deleted_bgs); 294 spin_lock_init(&cur_trans->dropped_roots_lock); 295 list_add_tail(&cur_trans->list, &fs_info->trans_list); 296 extent_io_tree_init(&cur_trans->dirty_pages, 297 fs_info->btree_inode->i_mapping); 298 fs_info->generation++; 299 cur_trans->transid = fs_info->generation; 300 fs_info->running_transaction = cur_trans; 301 cur_trans->aborted = 0; 302 spin_unlock(&fs_info->trans_lock); 303 304 return 0; 305 } 306 307 /* 308 * this does all the record keeping required to make sure that a reference 309 * counted root is properly recorded in a given transaction. This is required 310 * to make sure the old root from before we joined the transaction is deleted 311 * when the transaction commits 312 */ 313 static int record_root_in_trans(struct btrfs_trans_handle *trans, 314 struct btrfs_root *root) 315 { 316 if (test_bit(BTRFS_ROOT_REF_COWS, &root->state) && 317 root->last_trans < trans->transid) { 318 WARN_ON(root == root->fs_info->extent_root); 319 WARN_ON(root->commit_root != root->node); 320 321 /* 322 * see below for IN_TRANS_SETUP usage rules 323 * we have the reloc mutex held now, so there 324 * is only one writer in this function 325 */ 326 set_bit(BTRFS_ROOT_IN_TRANS_SETUP, &root->state); 327 328 /* make sure readers find IN_TRANS_SETUP before 329 * they find our root->last_trans update 330 */ 331 smp_wmb(); 332 333 spin_lock(&root->fs_info->fs_roots_radix_lock); 334 if (root->last_trans == trans->transid) { 335 spin_unlock(&root->fs_info->fs_roots_radix_lock); 336 return 0; 337 } 338 radix_tree_tag_set(&root->fs_info->fs_roots_radix, 339 (unsigned long)root->root_key.objectid, 340 BTRFS_ROOT_TRANS_TAG); 341 spin_unlock(&root->fs_info->fs_roots_radix_lock); 342 root->last_trans = trans->transid; 343 344 /* this is pretty tricky. We don't want to 345 * take the relocation lock in btrfs_record_root_in_trans 346 * unless we're really doing the first setup for this root in 347 * this transaction. 348 * 349 * Normally we'd use root->last_trans as a flag to decide 350 * if we want to take the expensive mutex. 351 * 352 * But, we have to set root->last_trans before we 353 * init the relocation root, otherwise, we trip over warnings 354 * in ctree.c. The solution used here is to flag ourselves 355 * with root IN_TRANS_SETUP. When this is 1, we're still 356 * fixing up the reloc trees and everyone must wait. 357 * 358 * When this is zero, they can trust root->last_trans and fly 359 * through btrfs_record_root_in_trans without having to take the 360 * lock. smp_wmb() makes sure that all the writes above are 361 * done before we pop in the zero below 362 */ 363 btrfs_init_reloc_root(trans, root); 364 smp_mb__before_atomic(); 365 clear_bit(BTRFS_ROOT_IN_TRANS_SETUP, &root->state); 366 } 367 return 0; 368 } 369 370 371 void btrfs_add_dropped_root(struct btrfs_trans_handle *trans, 372 struct btrfs_root *root) 373 { 374 struct btrfs_transaction *cur_trans = trans->transaction; 375 376 /* Add ourselves to the transaction dropped list */ 377 spin_lock(&cur_trans->dropped_roots_lock); 378 list_add_tail(&root->root_list, &cur_trans->dropped_roots); 379 spin_unlock(&cur_trans->dropped_roots_lock); 380 381 /* Make sure we don't try to update the root at commit time */ 382 spin_lock(&root->fs_info->fs_roots_radix_lock); 383 radix_tree_tag_clear(&root->fs_info->fs_roots_radix, 384 (unsigned long)root->root_key.objectid, 385 BTRFS_ROOT_TRANS_TAG); 386 spin_unlock(&root->fs_info->fs_roots_radix_lock); 387 } 388 389 int btrfs_record_root_in_trans(struct btrfs_trans_handle *trans, 390 struct btrfs_root *root) 391 { 392 if (!test_bit(BTRFS_ROOT_REF_COWS, &root->state)) 393 return 0; 394 395 /* 396 * see record_root_in_trans for comments about IN_TRANS_SETUP usage 397 * and barriers 398 */ 399 smp_rmb(); 400 if (root->last_trans == trans->transid && 401 !test_bit(BTRFS_ROOT_IN_TRANS_SETUP, &root->state)) 402 return 0; 403 404 mutex_lock(&root->fs_info->reloc_mutex); 405 record_root_in_trans(trans, root); 406 mutex_unlock(&root->fs_info->reloc_mutex); 407 408 return 0; 409 } 410 411 static inline int is_transaction_blocked(struct btrfs_transaction *trans) 412 { 413 return (trans->state >= TRANS_STATE_BLOCKED && 414 trans->state < TRANS_STATE_UNBLOCKED && 415 !trans->aborted); 416 } 417 418 /* wait for commit against the current transaction to become unblocked 419 * when this is done, it is safe to start a new transaction, but the current 420 * transaction might not be fully on disk. 421 */ 422 static void wait_current_trans(struct btrfs_root *root) 423 { 424 struct btrfs_transaction *cur_trans; 425 426 spin_lock(&root->fs_info->trans_lock); 427 cur_trans = root->fs_info->running_transaction; 428 if (cur_trans && is_transaction_blocked(cur_trans)) { 429 atomic_inc(&cur_trans->use_count); 430 spin_unlock(&root->fs_info->trans_lock); 431 432 wait_event(root->fs_info->transaction_wait, 433 cur_trans->state >= TRANS_STATE_UNBLOCKED || 434 cur_trans->aborted); 435 btrfs_put_transaction(cur_trans); 436 } else { 437 spin_unlock(&root->fs_info->trans_lock); 438 } 439 } 440 441 static int may_wait_transaction(struct btrfs_root *root, int type) 442 { 443 if (root->fs_info->log_root_recovering) 444 return 0; 445 446 if (type == TRANS_USERSPACE) 447 return 1; 448 449 if (type == TRANS_START && 450 !atomic_read(&root->fs_info->open_ioctl_trans)) 451 return 1; 452 453 return 0; 454 } 455 456 static inline bool need_reserve_reloc_root(struct btrfs_root *root) 457 { 458 if (!root->fs_info->reloc_ctl || 459 !test_bit(BTRFS_ROOT_REF_COWS, &root->state) || 460 root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID || 461 root->reloc_root) 462 return false; 463 464 return true; 465 } 466 467 static struct btrfs_trans_handle * 468 start_transaction(struct btrfs_root *root, unsigned int num_items, 469 unsigned int type, enum btrfs_reserve_flush_enum flush) 470 { 471 struct btrfs_trans_handle *h; 472 struct btrfs_transaction *cur_trans; 473 u64 num_bytes = 0; 474 u64 qgroup_reserved = 0; 475 bool reloc_reserved = false; 476 int ret; 477 478 /* Send isn't supposed to start transactions. */ 479 ASSERT(current->journal_info != BTRFS_SEND_TRANS_STUB); 480 481 if (test_bit(BTRFS_FS_STATE_ERROR, &root->fs_info->fs_state)) 482 return ERR_PTR(-EROFS); 483 484 if (current->journal_info) { 485 WARN_ON(type & TRANS_EXTWRITERS); 486 h = current->journal_info; 487 h->use_count++; 488 WARN_ON(h->use_count > 2); 489 h->orig_rsv = h->block_rsv; 490 h->block_rsv = NULL; 491 goto got_it; 492 } 493 494 /* 495 * Do the reservation before we join the transaction so we can do all 496 * the appropriate flushing if need be. 497 */ 498 if (num_items > 0 && root != root->fs_info->chunk_root) { 499 qgroup_reserved = num_items * root->nodesize; 500 ret = btrfs_qgroup_reserve_meta(root, qgroup_reserved); 501 if (ret) 502 return ERR_PTR(ret); 503 504 num_bytes = btrfs_calc_trans_metadata_size(root, num_items); 505 /* 506 * Do the reservation for the relocation root creation 507 */ 508 if (need_reserve_reloc_root(root)) { 509 num_bytes += root->nodesize; 510 reloc_reserved = true; 511 } 512 513 ret = btrfs_block_rsv_add(root, 514 &root->fs_info->trans_block_rsv, 515 num_bytes, flush); 516 if (ret) 517 goto reserve_fail; 518 } 519 again: 520 h = kmem_cache_zalloc(btrfs_trans_handle_cachep, GFP_NOFS); 521 if (!h) { 522 ret = -ENOMEM; 523 goto alloc_fail; 524 } 525 526 /* 527 * If we are JOIN_NOLOCK we're already committing a transaction and 528 * waiting on this guy, so we don't need to do the sb_start_intwrite 529 * because we're already holding a ref. We need this because we could 530 * have raced in and did an fsync() on a file which can kick a commit 531 * and then we deadlock with somebody doing a freeze. 532 * 533 * If we are ATTACH, it means we just want to catch the current 534 * transaction and commit it, so we needn't do sb_start_intwrite(). 535 */ 536 if (type & __TRANS_FREEZABLE) 537 sb_start_intwrite(root->fs_info->sb); 538 539 if (may_wait_transaction(root, type)) 540 wait_current_trans(root); 541 542 do { 543 ret = join_transaction(root, type); 544 if (ret == -EBUSY) { 545 wait_current_trans(root); 546 if (unlikely(type == TRANS_ATTACH)) 547 ret = -ENOENT; 548 } 549 } while (ret == -EBUSY); 550 551 if (ret < 0) { 552 /* We must get the transaction if we are JOIN_NOLOCK. */ 553 BUG_ON(type == TRANS_JOIN_NOLOCK); 554 goto join_fail; 555 } 556 557 cur_trans = root->fs_info->running_transaction; 558 559 h->transid = cur_trans->transid; 560 h->transaction = cur_trans; 561 h->root = root; 562 h->use_count = 1; 563 564 h->type = type; 565 h->can_flush_pending_bgs = true; 566 INIT_LIST_HEAD(&h->qgroup_ref_list); 567 INIT_LIST_HEAD(&h->new_bgs); 568 569 smp_mb(); 570 if (cur_trans->state >= TRANS_STATE_BLOCKED && 571 may_wait_transaction(root, type)) { 572 current->journal_info = h; 573 btrfs_commit_transaction(h, root); 574 goto again; 575 } 576 577 if (num_bytes) { 578 trace_btrfs_space_reservation(root->fs_info, "transaction", 579 h->transid, num_bytes, 1); 580 h->block_rsv = &root->fs_info->trans_block_rsv; 581 h->bytes_reserved = num_bytes; 582 h->reloc_reserved = reloc_reserved; 583 } 584 585 got_it: 586 btrfs_record_root_in_trans(h, root); 587 588 if (!current->journal_info && type != TRANS_USERSPACE) 589 current->journal_info = h; 590 return h; 591 592 join_fail: 593 if (type & __TRANS_FREEZABLE) 594 sb_end_intwrite(root->fs_info->sb); 595 kmem_cache_free(btrfs_trans_handle_cachep, h); 596 alloc_fail: 597 if (num_bytes) 598 btrfs_block_rsv_release(root, &root->fs_info->trans_block_rsv, 599 num_bytes); 600 reserve_fail: 601 btrfs_qgroup_free_meta(root, qgroup_reserved); 602 return ERR_PTR(ret); 603 } 604 605 struct btrfs_trans_handle *btrfs_start_transaction(struct btrfs_root *root, 606 unsigned int num_items) 607 { 608 return start_transaction(root, num_items, TRANS_START, 609 BTRFS_RESERVE_FLUSH_ALL); 610 } 611 struct btrfs_trans_handle *btrfs_start_transaction_fallback_global_rsv( 612 struct btrfs_root *root, 613 unsigned int num_items, 614 int min_factor) 615 { 616 struct btrfs_trans_handle *trans; 617 u64 num_bytes; 618 int ret; 619 620 trans = btrfs_start_transaction(root, num_items); 621 if (!IS_ERR(trans) || PTR_ERR(trans) != -ENOSPC) 622 return trans; 623 624 trans = btrfs_start_transaction(root, 0); 625 if (IS_ERR(trans)) 626 return trans; 627 628 num_bytes = btrfs_calc_trans_metadata_size(root, num_items); 629 ret = btrfs_cond_migrate_bytes(root->fs_info, 630 &root->fs_info->trans_block_rsv, 631 num_bytes, 632 min_factor); 633 if (ret) { 634 btrfs_end_transaction(trans, root); 635 return ERR_PTR(ret); 636 } 637 638 trans->block_rsv = &root->fs_info->trans_block_rsv; 639 trans->bytes_reserved = num_bytes; 640 trace_btrfs_space_reservation(root->fs_info, "transaction", 641 trans->transid, num_bytes, 1); 642 643 return trans; 644 } 645 646 struct btrfs_trans_handle *btrfs_start_transaction_lflush( 647 struct btrfs_root *root, 648 unsigned int num_items) 649 { 650 return start_transaction(root, num_items, TRANS_START, 651 BTRFS_RESERVE_FLUSH_LIMIT); 652 } 653 654 struct btrfs_trans_handle *btrfs_join_transaction(struct btrfs_root *root) 655 { 656 return start_transaction(root, 0, TRANS_JOIN, 657 BTRFS_RESERVE_NO_FLUSH); 658 } 659 660 struct btrfs_trans_handle *btrfs_join_transaction_nolock(struct btrfs_root *root) 661 { 662 return start_transaction(root, 0, TRANS_JOIN_NOLOCK, 663 BTRFS_RESERVE_NO_FLUSH); 664 } 665 666 struct btrfs_trans_handle *btrfs_start_ioctl_transaction(struct btrfs_root *root) 667 { 668 return start_transaction(root, 0, TRANS_USERSPACE, 669 BTRFS_RESERVE_NO_FLUSH); 670 } 671 672 /* 673 * btrfs_attach_transaction() - catch the running transaction 674 * 675 * It is used when we want to commit the current the transaction, but 676 * don't want to start a new one. 677 * 678 * Note: If this function return -ENOENT, it just means there is no 679 * running transaction. But it is possible that the inactive transaction 680 * is still in the memory, not fully on disk. If you hope there is no 681 * inactive transaction in the fs when -ENOENT is returned, you should 682 * invoke 683 * btrfs_attach_transaction_barrier() 684 */ 685 struct btrfs_trans_handle *btrfs_attach_transaction(struct btrfs_root *root) 686 { 687 return start_transaction(root, 0, TRANS_ATTACH, 688 BTRFS_RESERVE_NO_FLUSH); 689 } 690 691 /* 692 * btrfs_attach_transaction_barrier() - catch the running transaction 693 * 694 * It is similar to the above function, the differentia is this one 695 * will wait for all the inactive transactions until they fully 696 * complete. 697 */ 698 struct btrfs_trans_handle * 699 btrfs_attach_transaction_barrier(struct btrfs_root *root) 700 { 701 struct btrfs_trans_handle *trans; 702 703 trans = start_transaction(root, 0, TRANS_ATTACH, 704 BTRFS_RESERVE_NO_FLUSH); 705 if (IS_ERR(trans) && PTR_ERR(trans) == -ENOENT) 706 btrfs_wait_for_commit(root, 0); 707 708 return trans; 709 } 710 711 /* wait for a transaction commit to be fully complete */ 712 static noinline void wait_for_commit(struct btrfs_root *root, 713 struct btrfs_transaction *commit) 714 { 715 wait_event(commit->commit_wait, commit->state == TRANS_STATE_COMPLETED); 716 } 717 718 int btrfs_wait_for_commit(struct btrfs_root *root, u64 transid) 719 { 720 struct btrfs_transaction *cur_trans = NULL, *t; 721 int ret = 0; 722 723 if (transid) { 724 if (transid <= root->fs_info->last_trans_committed) 725 goto out; 726 727 /* find specified transaction */ 728 spin_lock(&root->fs_info->trans_lock); 729 list_for_each_entry(t, &root->fs_info->trans_list, list) { 730 if (t->transid == transid) { 731 cur_trans = t; 732 atomic_inc(&cur_trans->use_count); 733 ret = 0; 734 break; 735 } 736 if (t->transid > transid) { 737 ret = 0; 738 break; 739 } 740 } 741 spin_unlock(&root->fs_info->trans_lock); 742 743 /* 744 * The specified transaction doesn't exist, or we 745 * raced with btrfs_commit_transaction 746 */ 747 if (!cur_trans) { 748 if (transid > root->fs_info->last_trans_committed) 749 ret = -EINVAL; 750 goto out; 751 } 752 } else { 753 /* find newest transaction that is committing | committed */ 754 spin_lock(&root->fs_info->trans_lock); 755 list_for_each_entry_reverse(t, &root->fs_info->trans_list, 756 list) { 757 if (t->state >= TRANS_STATE_COMMIT_START) { 758 if (t->state == TRANS_STATE_COMPLETED) 759 break; 760 cur_trans = t; 761 atomic_inc(&cur_trans->use_count); 762 break; 763 } 764 } 765 spin_unlock(&root->fs_info->trans_lock); 766 if (!cur_trans) 767 goto out; /* nothing committing|committed */ 768 } 769 770 wait_for_commit(root, cur_trans); 771 btrfs_put_transaction(cur_trans); 772 out: 773 return ret; 774 } 775 776 void btrfs_throttle(struct btrfs_root *root) 777 { 778 if (!atomic_read(&root->fs_info->open_ioctl_trans)) 779 wait_current_trans(root); 780 } 781 782 static int should_end_transaction(struct btrfs_trans_handle *trans, 783 struct btrfs_root *root) 784 { 785 if (root->fs_info->global_block_rsv.space_info->full && 786 btrfs_check_space_for_delayed_refs(trans, root)) 787 return 1; 788 789 return !!btrfs_block_rsv_check(root, &root->fs_info->global_block_rsv, 5); 790 } 791 792 int btrfs_should_end_transaction(struct btrfs_trans_handle *trans, 793 struct btrfs_root *root) 794 { 795 struct btrfs_transaction *cur_trans = trans->transaction; 796 int updates; 797 int err; 798 799 smp_mb(); 800 if (cur_trans->state >= TRANS_STATE_BLOCKED || 801 cur_trans->delayed_refs.flushing) 802 return 1; 803 804 updates = trans->delayed_ref_updates; 805 trans->delayed_ref_updates = 0; 806 if (updates) { 807 err = btrfs_run_delayed_refs(trans, root, updates * 2); 808 if (err) /* Error code will also eval true */ 809 return err; 810 } 811 812 return should_end_transaction(trans, root); 813 } 814 815 static int __btrfs_end_transaction(struct btrfs_trans_handle *trans, 816 struct btrfs_root *root, int throttle) 817 { 818 struct btrfs_transaction *cur_trans = trans->transaction; 819 struct btrfs_fs_info *info = root->fs_info; 820 unsigned long cur = trans->delayed_ref_updates; 821 int lock = (trans->type != TRANS_JOIN_NOLOCK); 822 int err = 0; 823 int must_run_delayed_refs = 0; 824 825 if (trans->use_count > 1) { 826 trans->use_count--; 827 trans->block_rsv = trans->orig_rsv; 828 return 0; 829 } 830 831 btrfs_trans_release_metadata(trans, root); 832 trans->block_rsv = NULL; 833 834 if (!list_empty(&trans->new_bgs)) 835 btrfs_create_pending_block_groups(trans, root); 836 837 trans->delayed_ref_updates = 0; 838 if (!trans->sync) { 839 must_run_delayed_refs = 840 btrfs_should_throttle_delayed_refs(trans, root); 841 cur = max_t(unsigned long, cur, 32); 842 843 /* 844 * don't make the caller wait if they are from a NOLOCK 845 * or ATTACH transaction, it will deadlock with commit 846 */ 847 if (must_run_delayed_refs == 1 && 848 (trans->type & (__TRANS_JOIN_NOLOCK | __TRANS_ATTACH))) 849 must_run_delayed_refs = 2; 850 } 851 852 btrfs_trans_release_metadata(trans, root); 853 trans->block_rsv = NULL; 854 855 if (!list_empty(&trans->new_bgs)) 856 btrfs_create_pending_block_groups(trans, root); 857 858 btrfs_trans_release_chunk_metadata(trans); 859 860 if (lock && !atomic_read(&root->fs_info->open_ioctl_trans) && 861 should_end_transaction(trans, root) && 862 ACCESS_ONCE(cur_trans->state) == TRANS_STATE_RUNNING) { 863 spin_lock(&info->trans_lock); 864 if (cur_trans->state == TRANS_STATE_RUNNING) 865 cur_trans->state = TRANS_STATE_BLOCKED; 866 spin_unlock(&info->trans_lock); 867 } 868 869 if (lock && ACCESS_ONCE(cur_trans->state) == TRANS_STATE_BLOCKED) { 870 if (throttle) 871 return btrfs_commit_transaction(trans, root); 872 else 873 wake_up_process(info->transaction_kthread); 874 } 875 876 if (trans->type & __TRANS_FREEZABLE) 877 sb_end_intwrite(root->fs_info->sb); 878 879 WARN_ON(cur_trans != info->running_transaction); 880 WARN_ON(atomic_read(&cur_trans->num_writers) < 1); 881 atomic_dec(&cur_trans->num_writers); 882 extwriter_counter_dec(cur_trans, trans->type); 883 884 /* 885 * Make sure counter is updated before we wake up waiters. 886 */ 887 smp_mb(); 888 if (waitqueue_active(&cur_trans->writer_wait)) 889 wake_up(&cur_trans->writer_wait); 890 btrfs_put_transaction(cur_trans); 891 892 if (current->journal_info == trans) 893 current->journal_info = NULL; 894 895 if (throttle) 896 btrfs_run_delayed_iputs(root); 897 898 if (trans->aborted || 899 test_bit(BTRFS_FS_STATE_ERROR, &root->fs_info->fs_state)) { 900 wake_up_process(info->transaction_kthread); 901 err = -EIO; 902 } 903 assert_qgroups_uptodate(trans); 904 905 kmem_cache_free(btrfs_trans_handle_cachep, trans); 906 if (must_run_delayed_refs) { 907 btrfs_async_run_delayed_refs(root, cur, 908 must_run_delayed_refs == 1); 909 } 910 return err; 911 } 912 913 int btrfs_end_transaction(struct btrfs_trans_handle *trans, 914 struct btrfs_root *root) 915 { 916 return __btrfs_end_transaction(trans, root, 0); 917 } 918 919 int btrfs_end_transaction_throttle(struct btrfs_trans_handle *trans, 920 struct btrfs_root *root) 921 { 922 return __btrfs_end_transaction(trans, root, 1); 923 } 924 925 /* 926 * when btree blocks are allocated, they have some corresponding bits set for 927 * them in one of two extent_io trees. This is used to make sure all of 928 * those extents are sent to disk but does not wait on them 929 */ 930 int btrfs_write_marked_extents(struct btrfs_root *root, 931 struct extent_io_tree *dirty_pages, int mark) 932 { 933 int err = 0; 934 int werr = 0; 935 struct address_space *mapping = root->fs_info->btree_inode->i_mapping; 936 struct extent_state *cached_state = NULL; 937 u64 start = 0; 938 u64 end; 939 940 while (!find_first_extent_bit(dirty_pages, start, &start, &end, 941 mark, &cached_state)) { 942 bool wait_writeback = false; 943 944 err = convert_extent_bit(dirty_pages, start, end, 945 EXTENT_NEED_WAIT, 946 mark, &cached_state, GFP_NOFS); 947 /* 948 * convert_extent_bit can return -ENOMEM, which is most of the 949 * time a temporary error. So when it happens, ignore the error 950 * and wait for writeback of this range to finish - because we 951 * failed to set the bit EXTENT_NEED_WAIT for the range, a call 952 * to btrfs_wait_marked_extents() would not know that writeback 953 * for this range started and therefore wouldn't wait for it to 954 * finish - we don't want to commit a superblock that points to 955 * btree nodes/leafs for which writeback hasn't finished yet 956 * (and without errors). 957 * We cleanup any entries left in the io tree when committing 958 * the transaction (through clear_btree_io_tree()). 959 */ 960 if (err == -ENOMEM) { 961 err = 0; 962 wait_writeback = true; 963 } 964 if (!err) 965 err = filemap_fdatawrite_range(mapping, start, end); 966 if (err) 967 werr = err; 968 else if (wait_writeback) 969 werr = filemap_fdatawait_range(mapping, start, end); 970 free_extent_state(cached_state); 971 cached_state = NULL; 972 cond_resched(); 973 start = end + 1; 974 } 975 return werr; 976 } 977 978 /* 979 * when btree blocks are allocated, they have some corresponding bits set for 980 * them in one of two extent_io trees. This is used to make sure all of 981 * those extents are on disk for transaction or log commit. We wait 982 * on all the pages and clear them from the dirty pages state tree 983 */ 984 int btrfs_wait_marked_extents(struct btrfs_root *root, 985 struct extent_io_tree *dirty_pages, int mark) 986 { 987 int err = 0; 988 int werr = 0; 989 struct address_space *mapping = root->fs_info->btree_inode->i_mapping; 990 struct extent_state *cached_state = NULL; 991 u64 start = 0; 992 u64 end; 993 struct btrfs_inode *btree_ino = BTRFS_I(root->fs_info->btree_inode); 994 bool errors = false; 995 996 while (!find_first_extent_bit(dirty_pages, start, &start, &end, 997 EXTENT_NEED_WAIT, &cached_state)) { 998 /* 999 * Ignore -ENOMEM errors returned by clear_extent_bit(). 1000 * When committing the transaction, we'll remove any entries 1001 * left in the io tree. For a log commit, we don't remove them 1002 * after committing the log because the tree can be accessed 1003 * concurrently - we do it only at transaction commit time when 1004 * it's safe to do it (through clear_btree_io_tree()). 1005 */ 1006 err = clear_extent_bit(dirty_pages, start, end, 1007 EXTENT_NEED_WAIT, 1008 0, 0, &cached_state, GFP_NOFS); 1009 if (err == -ENOMEM) 1010 err = 0; 1011 if (!err) 1012 err = filemap_fdatawait_range(mapping, start, end); 1013 if (err) 1014 werr = err; 1015 free_extent_state(cached_state); 1016 cached_state = NULL; 1017 cond_resched(); 1018 start = end + 1; 1019 } 1020 if (err) 1021 werr = err; 1022 1023 if (root->root_key.objectid == BTRFS_TREE_LOG_OBJECTID) { 1024 if ((mark & EXTENT_DIRTY) && 1025 test_and_clear_bit(BTRFS_INODE_BTREE_LOG1_ERR, 1026 &btree_ino->runtime_flags)) 1027 errors = true; 1028 1029 if ((mark & EXTENT_NEW) && 1030 test_and_clear_bit(BTRFS_INODE_BTREE_LOG2_ERR, 1031 &btree_ino->runtime_flags)) 1032 errors = true; 1033 } else { 1034 if (test_and_clear_bit(BTRFS_INODE_BTREE_ERR, 1035 &btree_ino->runtime_flags)) 1036 errors = true; 1037 } 1038 1039 if (errors && !werr) 1040 werr = -EIO; 1041 1042 return werr; 1043 } 1044 1045 /* 1046 * when btree blocks are allocated, they have some corresponding bits set for 1047 * them in one of two extent_io trees. This is used to make sure all of 1048 * those extents are on disk for transaction or log commit 1049 */ 1050 static int btrfs_write_and_wait_marked_extents(struct btrfs_root *root, 1051 struct extent_io_tree *dirty_pages, int mark) 1052 { 1053 int ret; 1054 int ret2; 1055 struct blk_plug plug; 1056 1057 blk_start_plug(&plug); 1058 ret = btrfs_write_marked_extents(root, dirty_pages, mark); 1059 blk_finish_plug(&plug); 1060 ret2 = btrfs_wait_marked_extents(root, dirty_pages, mark); 1061 1062 if (ret) 1063 return ret; 1064 if (ret2) 1065 return ret2; 1066 return 0; 1067 } 1068 1069 static int btrfs_write_and_wait_transaction(struct btrfs_trans_handle *trans, 1070 struct btrfs_root *root) 1071 { 1072 int ret; 1073 1074 ret = btrfs_write_and_wait_marked_extents(root, 1075 &trans->transaction->dirty_pages, 1076 EXTENT_DIRTY); 1077 clear_btree_io_tree(&trans->transaction->dirty_pages); 1078 1079 return ret; 1080 } 1081 1082 /* 1083 * this is used to update the root pointer in the tree of tree roots. 1084 * 1085 * But, in the case of the extent allocation tree, updating the root 1086 * pointer may allocate blocks which may change the root of the extent 1087 * allocation tree. 1088 * 1089 * So, this loops and repeats and makes sure the cowonly root didn't 1090 * change while the root pointer was being updated in the metadata. 1091 */ 1092 static int update_cowonly_root(struct btrfs_trans_handle *trans, 1093 struct btrfs_root *root) 1094 { 1095 int ret; 1096 u64 old_root_bytenr; 1097 u64 old_root_used; 1098 struct btrfs_root *tree_root = root->fs_info->tree_root; 1099 1100 old_root_used = btrfs_root_used(&root->root_item); 1101 1102 while (1) { 1103 old_root_bytenr = btrfs_root_bytenr(&root->root_item); 1104 if (old_root_bytenr == root->node->start && 1105 old_root_used == btrfs_root_used(&root->root_item)) 1106 break; 1107 1108 btrfs_set_root_node(&root->root_item, root->node); 1109 ret = btrfs_update_root(trans, tree_root, 1110 &root->root_key, 1111 &root->root_item); 1112 if (ret) 1113 return ret; 1114 1115 old_root_used = btrfs_root_used(&root->root_item); 1116 } 1117 1118 return 0; 1119 } 1120 1121 /* 1122 * update all the cowonly tree roots on disk 1123 * 1124 * The error handling in this function may not be obvious. Any of the 1125 * failures will cause the file system to go offline. We still need 1126 * to clean up the delayed refs. 1127 */ 1128 static noinline int commit_cowonly_roots(struct btrfs_trans_handle *trans, 1129 struct btrfs_root *root) 1130 { 1131 struct btrfs_fs_info *fs_info = root->fs_info; 1132 struct list_head *dirty_bgs = &trans->transaction->dirty_bgs; 1133 struct list_head *io_bgs = &trans->transaction->io_bgs; 1134 struct list_head *next; 1135 struct extent_buffer *eb; 1136 int ret; 1137 1138 eb = btrfs_lock_root_node(fs_info->tree_root); 1139 ret = btrfs_cow_block(trans, fs_info->tree_root, eb, NULL, 1140 0, &eb); 1141 btrfs_tree_unlock(eb); 1142 free_extent_buffer(eb); 1143 1144 if (ret) 1145 return ret; 1146 1147 ret = btrfs_run_delayed_refs(trans, root, (unsigned long)-1); 1148 if (ret) 1149 return ret; 1150 1151 ret = btrfs_run_dev_stats(trans, root->fs_info); 1152 if (ret) 1153 return ret; 1154 ret = btrfs_run_dev_replace(trans, root->fs_info); 1155 if (ret) 1156 return ret; 1157 ret = btrfs_run_qgroups(trans, root->fs_info); 1158 if (ret) 1159 return ret; 1160 1161 ret = btrfs_setup_space_cache(trans, root); 1162 if (ret) 1163 return ret; 1164 1165 /* run_qgroups might have added some more refs */ 1166 ret = btrfs_run_delayed_refs(trans, root, (unsigned long)-1); 1167 if (ret) 1168 return ret; 1169 again: 1170 while (!list_empty(&fs_info->dirty_cowonly_roots)) { 1171 next = fs_info->dirty_cowonly_roots.next; 1172 list_del_init(next); 1173 root = list_entry(next, struct btrfs_root, dirty_list); 1174 clear_bit(BTRFS_ROOT_DIRTY, &root->state); 1175 1176 if (root != fs_info->extent_root) 1177 list_add_tail(&root->dirty_list, 1178 &trans->transaction->switch_commits); 1179 ret = update_cowonly_root(trans, root); 1180 if (ret) 1181 return ret; 1182 ret = btrfs_run_delayed_refs(trans, root, (unsigned long)-1); 1183 if (ret) 1184 return ret; 1185 } 1186 1187 while (!list_empty(dirty_bgs) || !list_empty(io_bgs)) { 1188 ret = btrfs_write_dirty_block_groups(trans, root); 1189 if (ret) 1190 return ret; 1191 ret = btrfs_run_delayed_refs(trans, root, (unsigned long)-1); 1192 if (ret) 1193 return ret; 1194 } 1195 1196 if (!list_empty(&fs_info->dirty_cowonly_roots)) 1197 goto again; 1198 1199 list_add_tail(&fs_info->extent_root->dirty_list, 1200 &trans->transaction->switch_commits); 1201 btrfs_after_dev_replace_commit(fs_info); 1202 1203 return 0; 1204 } 1205 1206 /* 1207 * dead roots are old snapshots that need to be deleted. This allocates 1208 * a dirty root struct and adds it into the list of dead roots that need to 1209 * be deleted 1210 */ 1211 void btrfs_add_dead_root(struct btrfs_root *root) 1212 { 1213 spin_lock(&root->fs_info->trans_lock); 1214 if (list_empty(&root->root_list)) 1215 list_add_tail(&root->root_list, &root->fs_info->dead_roots); 1216 spin_unlock(&root->fs_info->trans_lock); 1217 } 1218 1219 /* 1220 * update all the cowonly tree roots on disk 1221 */ 1222 static noinline int commit_fs_roots(struct btrfs_trans_handle *trans, 1223 struct btrfs_root *root) 1224 { 1225 struct btrfs_root *gang[8]; 1226 struct btrfs_fs_info *fs_info = root->fs_info; 1227 int i; 1228 int ret; 1229 int err = 0; 1230 1231 spin_lock(&fs_info->fs_roots_radix_lock); 1232 while (1) { 1233 ret = radix_tree_gang_lookup_tag(&fs_info->fs_roots_radix, 1234 (void **)gang, 0, 1235 ARRAY_SIZE(gang), 1236 BTRFS_ROOT_TRANS_TAG); 1237 if (ret == 0) 1238 break; 1239 for (i = 0; i < ret; i++) { 1240 root = gang[i]; 1241 radix_tree_tag_clear(&fs_info->fs_roots_radix, 1242 (unsigned long)root->root_key.objectid, 1243 BTRFS_ROOT_TRANS_TAG); 1244 spin_unlock(&fs_info->fs_roots_radix_lock); 1245 1246 btrfs_free_log(trans, root); 1247 btrfs_update_reloc_root(trans, root); 1248 btrfs_orphan_commit_root(trans, root); 1249 1250 btrfs_save_ino_cache(root, trans); 1251 1252 /* see comments in should_cow_block() */ 1253 clear_bit(BTRFS_ROOT_FORCE_COW, &root->state); 1254 smp_mb__after_atomic(); 1255 1256 if (root->commit_root != root->node) { 1257 list_add_tail(&root->dirty_list, 1258 &trans->transaction->switch_commits); 1259 btrfs_set_root_node(&root->root_item, 1260 root->node); 1261 } 1262 1263 err = btrfs_update_root(trans, fs_info->tree_root, 1264 &root->root_key, 1265 &root->root_item); 1266 spin_lock(&fs_info->fs_roots_radix_lock); 1267 if (err) 1268 break; 1269 btrfs_qgroup_free_meta_all(root); 1270 } 1271 } 1272 spin_unlock(&fs_info->fs_roots_radix_lock); 1273 return err; 1274 } 1275 1276 /* 1277 * defrag a given btree. 1278 * Every leaf in the btree is read and defragged. 1279 */ 1280 int btrfs_defrag_root(struct btrfs_root *root) 1281 { 1282 struct btrfs_fs_info *info = root->fs_info; 1283 struct btrfs_trans_handle *trans; 1284 int ret; 1285 1286 if (test_and_set_bit(BTRFS_ROOT_DEFRAG_RUNNING, &root->state)) 1287 return 0; 1288 1289 while (1) { 1290 trans = btrfs_start_transaction(root, 0); 1291 if (IS_ERR(trans)) 1292 return PTR_ERR(trans); 1293 1294 ret = btrfs_defrag_leaves(trans, root); 1295 1296 btrfs_end_transaction(trans, root); 1297 btrfs_btree_balance_dirty(info->tree_root); 1298 cond_resched(); 1299 1300 if (btrfs_fs_closing(root->fs_info) || ret != -EAGAIN) 1301 break; 1302 1303 if (btrfs_defrag_cancelled(root->fs_info)) { 1304 pr_debug("BTRFS: defrag_root cancelled\n"); 1305 ret = -EAGAIN; 1306 break; 1307 } 1308 } 1309 clear_bit(BTRFS_ROOT_DEFRAG_RUNNING, &root->state); 1310 return ret; 1311 } 1312 1313 /* 1314 * new snapshots need to be created at a very specific time in the 1315 * transaction commit. This does the actual creation. 1316 * 1317 * Note: 1318 * If the error which may affect the commitment of the current transaction 1319 * happens, we should return the error number. If the error which just affect 1320 * the creation of the pending snapshots, just return 0. 1321 */ 1322 static noinline int create_pending_snapshot(struct btrfs_trans_handle *trans, 1323 struct btrfs_fs_info *fs_info, 1324 struct btrfs_pending_snapshot *pending) 1325 { 1326 struct btrfs_key key; 1327 struct btrfs_root_item *new_root_item; 1328 struct btrfs_root *tree_root = fs_info->tree_root; 1329 struct btrfs_root *root = pending->root; 1330 struct btrfs_root *parent_root; 1331 struct btrfs_block_rsv *rsv; 1332 struct inode *parent_inode; 1333 struct btrfs_path *path; 1334 struct btrfs_dir_item *dir_item; 1335 struct dentry *dentry; 1336 struct extent_buffer *tmp; 1337 struct extent_buffer *old; 1338 struct timespec cur_time; 1339 int ret = 0; 1340 u64 to_reserve = 0; 1341 u64 index = 0; 1342 u64 objectid; 1343 u64 root_flags; 1344 uuid_le new_uuid; 1345 1346 ASSERT(pending->path); 1347 path = pending->path; 1348 1349 ASSERT(pending->root_item); 1350 new_root_item = pending->root_item; 1351 1352 pending->error = btrfs_find_free_objectid(tree_root, &objectid); 1353 if (pending->error) 1354 goto no_free_objectid; 1355 1356 /* 1357 * Make qgroup to skip current new snapshot's qgroupid, as it is 1358 * accounted by later btrfs_qgroup_inherit(). 1359 */ 1360 btrfs_set_skip_qgroup(trans, objectid); 1361 1362 btrfs_reloc_pre_snapshot(pending, &to_reserve); 1363 1364 if (to_reserve > 0) { 1365 pending->error = btrfs_block_rsv_add(root, 1366 &pending->block_rsv, 1367 to_reserve, 1368 BTRFS_RESERVE_NO_FLUSH); 1369 if (pending->error) 1370 goto clear_skip_qgroup; 1371 } 1372 1373 key.objectid = objectid; 1374 key.offset = (u64)-1; 1375 key.type = BTRFS_ROOT_ITEM_KEY; 1376 1377 rsv = trans->block_rsv; 1378 trans->block_rsv = &pending->block_rsv; 1379 trans->bytes_reserved = trans->block_rsv->reserved; 1380 trace_btrfs_space_reservation(root->fs_info, "transaction", 1381 trans->transid, 1382 trans->bytes_reserved, 1); 1383 dentry = pending->dentry; 1384 parent_inode = pending->dir; 1385 parent_root = BTRFS_I(parent_inode)->root; 1386 record_root_in_trans(trans, parent_root); 1387 1388 cur_time = current_fs_time(parent_inode->i_sb); 1389 1390 /* 1391 * insert the directory item 1392 */ 1393 ret = btrfs_set_inode_index(parent_inode, &index); 1394 BUG_ON(ret); /* -ENOMEM */ 1395 1396 /* check if there is a file/dir which has the same name. */ 1397 dir_item = btrfs_lookup_dir_item(NULL, parent_root, path, 1398 btrfs_ino(parent_inode), 1399 dentry->d_name.name, 1400 dentry->d_name.len, 0); 1401 if (dir_item != NULL && !IS_ERR(dir_item)) { 1402 pending->error = -EEXIST; 1403 goto dir_item_existed; 1404 } else if (IS_ERR(dir_item)) { 1405 ret = PTR_ERR(dir_item); 1406 btrfs_abort_transaction(trans, root, ret); 1407 goto fail; 1408 } 1409 btrfs_release_path(path); 1410 1411 /* 1412 * pull in the delayed directory update 1413 * and the delayed inode item 1414 * otherwise we corrupt the FS during 1415 * snapshot 1416 */ 1417 ret = btrfs_run_delayed_items(trans, root); 1418 if (ret) { /* Transaction aborted */ 1419 btrfs_abort_transaction(trans, root, ret); 1420 goto fail; 1421 } 1422 1423 record_root_in_trans(trans, root); 1424 btrfs_set_root_last_snapshot(&root->root_item, trans->transid); 1425 memcpy(new_root_item, &root->root_item, sizeof(*new_root_item)); 1426 btrfs_check_and_init_root_item(new_root_item); 1427 1428 root_flags = btrfs_root_flags(new_root_item); 1429 if (pending->readonly) 1430 root_flags |= BTRFS_ROOT_SUBVOL_RDONLY; 1431 else 1432 root_flags &= ~BTRFS_ROOT_SUBVOL_RDONLY; 1433 btrfs_set_root_flags(new_root_item, root_flags); 1434 1435 btrfs_set_root_generation_v2(new_root_item, 1436 trans->transid); 1437 uuid_le_gen(&new_uuid); 1438 memcpy(new_root_item->uuid, new_uuid.b, BTRFS_UUID_SIZE); 1439 memcpy(new_root_item->parent_uuid, root->root_item.uuid, 1440 BTRFS_UUID_SIZE); 1441 if (!(root_flags & BTRFS_ROOT_SUBVOL_RDONLY)) { 1442 memset(new_root_item->received_uuid, 0, 1443 sizeof(new_root_item->received_uuid)); 1444 memset(&new_root_item->stime, 0, sizeof(new_root_item->stime)); 1445 memset(&new_root_item->rtime, 0, sizeof(new_root_item->rtime)); 1446 btrfs_set_root_stransid(new_root_item, 0); 1447 btrfs_set_root_rtransid(new_root_item, 0); 1448 } 1449 btrfs_set_stack_timespec_sec(&new_root_item->otime, cur_time.tv_sec); 1450 btrfs_set_stack_timespec_nsec(&new_root_item->otime, cur_time.tv_nsec); 1451 btrfs_set_root_otransid(new_root_item, trans->transid); 1452 1453 old = btrfs_lock_root_node(root); 1454 ret = btrfs_cow_block(trans, root, old, NULL, 0, &old); 1455 if (ret) { 1456 btrfs_tree_unlock(old); 1457 free_extent_buffer(old); 1458 btrfs_abort_transaction(trans, root, ret); 1459 goto fail; 1460 } 1461 1462 btrfs_set_lock_blocking(old); 1463 1464 ret = btrfs_copy_root(trans, root, old, &tmp, objectid); 1465 /* clean up in any case */ 1466 btrfs_tree_unlock(old); 1467 free_extent_buffer(old); 1468 if (ret) { 1469 btrfs_abort_transaction(trans, root, ret); 1470 goto fail; 1471 } 1472 /* see comments in should_cow_block() */ 1473 set_bit(BTRFS_ROOT_FORCE_COW, &root->state); 1474 smp_wmb(); 1475 1476 btrfs_set_root_node(new_root_item, tmp); 1477 /* record when the snapshot was created in key.offset */ 1478 key.offset = trans->transid; 1479 ret = btrfs_insert_root(trans, tree_root, &key, new_root_item); 1480 btrfs_tree_unlock(tmp); 1481 free_extent_buffer(tmp); 1482 if (ret) { 1483 btrfs_abort_transaction(trans, root, ret); 1484 goto fail; 1485 } 1486 1487 /* 1488 * insert root back/forward references 1489 */ 1490 ret = btrfs_add_root_ref(trans, tree_root, objectid, 1491 parent_root->root_key.objectid, 1492 btrfs_ino(parent_inode), index, 1493 dentry->d_name.name, dentry->d_name.len); 1494 if (ret) { 1495 btrfs_abort_transaction(trans, root, ret); 1496 goto fail; 1497 } 1498 1499 key.offset = (u64)-1; 1500 pending->snap = btrfs_read_fs_root_no_name(root->fs_info, &key); 1501 if (IS_ERR(pending->snap)) { 1502 ret = PTR_ERR(pending->snap); 1503 btrfs_abort_transaction(trans, root, ret); 1504 goto fail; 1505 } 1506 1507 ret = btrfs_reloc_post_snapshot(trans, pending); 1508 if (ret) { 1509 btrfs_abort_transaction(trans, root, ret); 1510 goto fail; 1511 } 1512 1513 ret = btrfs_run_delayed_refs(trans, root, (unsigned long)-1); 1514 if (ret) { 1515 btrfs_abort_transaction(trans, root, ret); 1516 goto fail; 1517 } 1518 1519 ret = btrfs_insert_dir_item(trans, parent_root, 1520 dentry->d_name.name, dentry->d_name.len, 1521 parent_inode, &key, 1522 BTRFS_FT_DIR, index); 1523 /* We have check then name at the beginning, so it is impossible. */ 1524 BUG_ON(ret == -EEXIST || ret == -EOVERFLOW); 1525 if (ret) { 1526 btrfs_abort_transaction(trans, root, ret); 1527 goto fail; 1528 } 1529 1530 btrfs_i_size_write(parent_inode, parent_inode->i_size + 1531 dentry->d_name.len * 2); 1532 parent_inode->i_mtime = parent_inode->i_ctime = 1533 current_fs_time(parent_inode->i_sb); 1534 ret = btrfs_update_inode_fallback(trans, parent_root, parent_inode); 1535 if (ret) { 1536 btrfs_abort_transaction(trans, root, ret); 1537 goto fail; 1538 } 1539 ret = btrfs_uuid_tree_add(trans, fs_info->uuid_root, new_uuid.b, 1540 BTRFS_UUID_KEY_SUBVOL, objectid); 1541 if (ret) { 1542 btrfs_abort_transaction(trans, root, ret); 1543 goto fail; 1544 } 1545 if (!btrfs_is_empty_uuid(new_root_item->received_uuid)) { 1546 ret = btrfs_uuid_tree_add(trans, fs_info->uuid_root, 1547 new_root_item->received_uuid, 1548 BTRFS_UUID_KEY_RECEIVED_SUBVOL, 1549 objectid); 1550 if (ret && ret != -EEXIST) { 1551 btrfs_abort_transaction(trans, root, ret); 1552 goto fail; 1553 } 1554 } 1555 1556 ret = btrfs_run_delayed_refs(trans, root, (unsigned long)-1); 1557 if (ret) { 1558 btrfs_abort_transaction(trans, root, ret); 1559 goto fail; 1560 } 1561 1562 /* 1563 * account qgroup counters before qgroup_inherit() 1564 */ 1565 ret = btrfs_qgroup_prepare_account_extents(trans, fs_info); 1566 if (ret) 1567 goto fail; 1568 ret = btrfs_qgroup_account_extents(trans, fs_info); 1569 if (ret) 1570 goto fail; 1571 ret = btrfs_qgroup_inherit(trans, fs_info, 1572 root->root_key.objectid, 1573 objectid, pending->inherit); 1574 if (ret) { 1575 btrfs_abort_transaction(trans, root, ret); 1576 goto fail; 1577 } 1578 1579 fail: 1580 pending->error = ret; 1581 dir_item_existed: 1582 trans->block_rsv = rsv; 1583 trans->bytes_reserved = 0; 1584 clear_skip_qgroup: 1585 btrfs_clear_skip_qgroup(trans); 1586 no_free_objectid: 1587 kfree(new_root_item); 1588 pending->root_item = NULL; 1589 btrfs_free_path(path); 1590 pending->path = NULL; 1591 1592 return ret; 1593 } 1594 1595 /* 1596 * create all the snapshots we've scheduled for creation 1597 */ 1598 static noinline int create_pending_snapshots(struct btrfs_trans_handle *trans, 1599 struct btrfs_fs_info *fs_info) 1600 { 1601 struct btrfs_pending_snapshot *pending, *next; 1602 struct list_head *head = &trans->transaction->pending_snapshots; 1603 int ret = 0; 1604 1605 list_for_each_entry_safe(pending, next, head, list) { 1606 list_del(&pending->list); 1607 ret = create_pending_snapshot(trans, fs_info, pending); 1608 if (ret) 1609 break; 1610 } 1611 return ret; 1612 } 1613 1614 static void update_super_roots(struct btrfs_root *root) 1615 { 1616 struct btrfs_root_item *root_item; 1617 struct btrfs_super_block *super; 1618 1619 super = root->fs_info->super_copy; 1620 1621 root_item = &root->fs_info->chunk_root->root_item; 1622 super->chunk_root = root_item->bytenr; 1623 super->chunk_root_generation = root_item->generation; 1624 super->chunk_root_level = root_item->level; 1625 1626 root_item = &root->fs_info->tree_root->root_item; 1627 super->root = root_item->bytenr; 1628 super->generation = root_item->generation; 1629 super->root_level = root_item->level; 1630 if (btrfs_test_opt(root, SPACE_CACHE)) 1631 super->cache_generation = root_item->generation; 1632 if (root->fs_info->update_uuid_tree_gen) 1633 super->uuid_tree_generation = root_item->generation; 1634 } 1635 1636 int btrfs_transaction_in_commit(struct btrfs_fs_info *info) 1637 { 1638 struct btrfs_transaction *trans; 1639 int ret = 0; 1640 1641 spin_lock(&info->trans_lock); 1642 trans = info->running_transaction; 1643 if (trans) 1644 ret = (trans->state >= TRANS_STATE_COMMIT_START); 1645 spin_unlock(&info->trans_lock); 1646 return ret; 1647 } 1648 1649 int btrfs_transaction_blocked(struct btrfs_fs_info *info) 1650 { 1651 struct btrfs_transaction *trans; 1652 int ret = 0; 1653 1654 spin_lock(&info->trans_lock); 1655 trans = info->running_transaction; 1656 if (trans) 1657 ret = is_transaction_blocked(trans); 1658 spin_unlock(&info->trans_lock); 1659 return ret; 1660 } 1661 1662 /* 1663 * wait for the current transaction commit to start and block subsequent 1664 * transaction joins 1665 */ 1666 static void wait_current_trans_commit_start(struct btrfs_root *root, 1667 struct btrfs_transaction *trans) 1668 { 1669 wait_event(root->fs_info->transaction_blocked_wait, 1670 trans->state >= TRANS_STATE_COMMIT_START || 1671 trans->aborted); 1672 } 1673 1674 /* 1675 * wait for the current transaction to start and then become unblocked. 1676 * caller holds ref. 1677 */ 1678 static void wait_current_trans_commit_start_and_unblock(struct btrfs_root *root, 1679 struct btrfs_transaction *trans) 1680 { 1681 wait_event(root->fs_info->transaction_wait, 1682 trans->state >= TRANS_STATE_UNBLOCKED || 1683 trans->aborted); 1684 } 1685 1686 /* 1687 * commit transactions asynchronously. once btrfs_commit_transaction_async 1688 * returns, any subsequent transaction will not be allowed to join. 1689 */ 1690 struct btrfs_async_commit { 1691 struct btrfs_trans_handle *newtrans; 1692 struct btrfs_root *root; 1693 struct work_struct work; 1694 }; 1695 1696 static void do_async_commit(struct work_struct *work) 1697 { 1698 struct btrfs_async_commit *ac = 1699 container_of(work, struct btrfs_async_commit, work); 1700 1701 /* 1702 * We've got freeze protection passed with the transaction. 1703 * Tell lockdep about it. 1704 */ 1705 if (ac->newtrans->type & __TRANS_FREEZABLE) 1706 __sb_writers_acquired(ac->root->fs_info->sb, SB_FREEZE_FS); 1707 1708 current->journal_info = ac->newtrans; 1709 1710 btrfs_commit_transaction(ac->newtrans, ac->root); 1711 kfree(ac); 1712 } 1713 1714 int btrfs_commit_transaction_async(struct btrfs_trans_handle *trans, 1715 struct btrfs_root *root, 1716 int wait_for_unblock) 1717 { 1718 struct btrfs_async_commit *ac; 1719 struct btrfs_transaction *cur_trans; 1720 1721 ac = kmalloc(sizeof(*ac), GFP_NOFS); 1722 if (!ac) 1723 return -ENOMEM; 1724 1725 INIT_WORK(&ac->work, do_async_commit); 1726 ac->root = root; 1727 ac->newtrans = btrfs_join_transaction(root); 1728 if (IS_ERR(ac->newtrans)) { 1729 int err = PTR_ERR(ac->newtrans); 1730 kfree(ac); 1731 return err; 1732 } 1733 1734 /* take transaction reference */ 1735 cur_trans = trans->transaction; 1736 atomic_inc(&cur_trans->use_count); 1737 1738 btrfs_end_transaction(trans, root); 1739 1740 /* 1741 * Tell lockdep we've released the freeze rwsem, since the 1742 * async commit thread will be the one to unlock it. 1743 */ 1744 if (ac->newtrans->type & __TRANS_FREEZABLE) 1745 __sb_writers_release(root->fs_info->sb, SB_FREEZE_FS); 1746 1747 schedule_work(&ac->work); 1748 1749 /* wait for transaction to start and unblock */ 1750 if (wait_for_unblock) 1751 wait_current_trans_commit_start_and_unblock(root, cur_trans); 1752 else 1753 wait_current_trans_commit_start(root, cur_trans); 1754 1755 if (current->journal_info == trans) 1756 current->journal_info = NULL; 1757 1758 btrfs_put_transaction(cur_trans); 1759 return 0; 1760 } 1761 1762 1763 static void cleanup_transaction(struct btrfs_trans_handle *trans, 1764 struct btrfs_root *root, int err) 1765 { 1766 struct btrfs_transaction *cur_trans = trans->transaction; 1767 DEFINE_WAIT(wait); 1768 1769 WARN_ON(trans->use_count > 1); 1770 1771 btrfs_abort_transaction(trans, root, err); 1772 1773 spin_lock(&root->fs_info->trans_lock); 1774 1775 /* 1776 * If the transaction is removed from the list, it means this 1777 * transaction has been committed successfully, so it is impossible 1778 * to call the cleanup function. 1779 */ 1780 BUG_ON(list_empty(&cur_trans->list)); 1781 1782 list_del_init(&cur_trans->list); 1783 if (cur_trans == root->fs_info->running_transaction) { 1784 cur_trans->state = TRANS_STATE_COMMIT_DOING; 1785 spin_unlock(&root->fs_info->trans_lock); 1786 wait_event(cur_trans->writer_wait, 1787 atomic_read(&cur_trans->num_writers) == 1); 1788 1789 spin_lock(&root->fs_info->trans_lock); 1790 } 1791 spin_unlock(&root->fs_info->trans_lock); 1792 1793 btrfs_cleanup_one_transaction(trans->transaction, root); 1794 1795 spin_lock(&root->fs_info->trans_lock); 1796 if (cur_trans == root->fs_info->running_transaction) 1797 root->fs_info->running_transaction = NULL; 1798 spin_unlock(&root->fs_info->trans_lock); 1799 1800 if (trans->type & __TRANS_FREEZABLE) 1801 sb_end_intwrite(root->fs_info->sb); 1802 btrfs_put_transaction(cur_trans); 1803 btrfs_put_transaction(cur_trans); 1804 1805 trace_btrfs_transaction_commit(root); 1806 1807 if (current->journal_info == trans) 1808 current->journal_info = NULL; 1809 btrfs_scrub_cancel(root->fs_info); 1810 1811 kmem_cache_free(btrfs_trans_handle_cachep, trans); 1812 } 1813 1814 static inline int btrfs_start_delalloc_flush(struct btrfs_fs_info *fs_info) 1815 { 1816 if (btrfs_test_opt(fs_info->tree_root, FLUSHONCOMMIT)) 1817 return btrfs_start_delalloc_roots(fs_info, 1, -1); 1818 return 0; 1819 } 1820 1821 static inline void btrfs_wait_delalloc_flush(struct btrfs_fs_info *fs_info) 1822 { 1823 if (btrfs_test_opt(fs_info->tree_root, FLUSHONCOMMIT)) 1824 btrfs_wait_ordered_roots(fs_info, -1); 1825 } 1826 1827 static inline void 1828 btrfs_wait_pending_ordered(struct btrfs_transaction *cur_trans) 1829 { 1830 wait_event(cur_trans->pending_wait, 1831 atomic_read(&cur_trans->pending_ordered) == 0); 1832 } 1833 1834 int btrfs_commit_transaction(struct btrfs_trans_handle *trans, 1835 struct btrfs_root *root) 1836 { 1837 struct btrfs_transaction *cur_trans = trans->transaction; 1838 struct btrfs_transaction *prev_trans = NULL; 1839 struct btrfs_inode *btree_ino = BTRFS_I(root->fs_info->btree_inode); 1840 int ret; 1841 1842 /* Stop the commit early if ->aborted is set */ 1843 if (unlikely(ACCESS_ONCE(cur_trans->aborted))) { 1844 ret = cur_trans->aborted; 1845 btrfs_end_transaction(trans, root); 1846 return ret; 1847 } 1848 1849 /* make a pass through all the delayed refs we have so far 1850 * any runnings procs may add more while we are here 1851 */ 1852 ret = btrfs_run_delayed_refs(trans, root, 0); 1853 if (ret) { 1854 btrfs_end_transaction(trans, root); 1855 return ret; 1856 } 1857 1858 btrfs_trans_release_metadata(trans, root); 1859 trans->block_rsv = NULL; 1860 1861 cur_trans = trans->transaction; 1862 1863 /* 1864 * set the flushing flag so procs in this transaction have to 1865 * start sending their work down. 1866 */ 1867 cur_trans->delayed_refs.flushing = 1; 1868 smp_wmb(); 1869 1870 if (!list_empty(&trans->new_bgs)) 1871 btrfs_create_pending_block_groups(trans, root); 1872 1873 ret = btrfs_run_delayed_refs(trans, root, 0); 1874 if (ret) { 1875 btrfs_end_transaction(trans, root); 1876 return ret; 1877 } 1878 1879 if (!test_bit(BTRFS_TRANS_DIRTY_BG_RUN, &cur_trans->flags)) { 1880 int run_it = 0; 1881 1882 /* this mutex is also taken before trying to set 1883 * block groups readonly. We need to make sure 1884 * that nobody has set a block group readonly 1885 * after a extents from that block group have been 1886 * allocated for cache files. btrfs_set_block_group_ro 1887 * will wait for the transaction to commit if it 1888 * finds BTRFS_TRANS_DIRTY_BG_RUN set. 1889 * 1890 * The BTRFS_TRANS_DIRTY_BG_RUN flag is also used to make sure 1891 * only one process starts all the block group IO. It wouldn't 1892 * hurt to have more than one go through, but there's no 1893 * real advantage to it either. 1894 */ 1895 mutex_lock(&root->fs_info->ro_block_group_mutex); 1896 if (!test_and_set_bit(BTRFS_TRANS_DIRTY_BG_RUN, 1897 &cur_trans->flags)) 1898 run_it = 1; 1899 mutex_unlock(&root->fs_info->ro_block_group_mutex); 1900 1901 if (run_it) 1902 ret = btrfs_start_dirty_block_groups(trans, root); 1903 } 1904 if (ret) { 1905 btrfs_end_transaction(trans, root); 1906 return ret; 1907 } 1908 1909 spin_lock(&root->fs_info->trans_lock); 1910 if (cur_trans->state >= TRANS_STATE_COMMIT_START) { 1911 spin_unlock(&root->fs_info->trans_lock); 1912 atomic_inc(&cur_trans->use_count); 1913 ret = btrfs_end_transaction(trans, root); 1914 1915 wait_for_commit(root, cur_trans); 1916 1917 if (unlikely(cur_trans->aborted)) 1918 ret = cur_trans->aborted; 1919 1920 btrfs_put_transaction(cur_trans); 1921 1922 return ret; 1923 } 1924 1925 cur_trans->state = TRANS_STATE_COMMIT_START; 1926 wake_up(&root->fs_info->transaction_blocked_wait); 1927 1928 if (cur_trans->list.prev != &root->fs_info->trans_list) { 1929 prev_trans = list_entry(cur_trans->list.prev, 1930 struct btrfs_transaction, list); 1931 if (prev_trans->state != TRANS_STATE_COMPLETED) { 1932 atomic_inc(&prev_trans->use_count); 1933 spin_unlock(&root->fs_info->trans_lock); 1934 1935 wait_for_commit(root, prev_trans); 1936 ret = prev_trans->aborted; 1937 1938 btrfs_put_transaction(prev_trans); 1939 if (ret) 1940 goto cleanup_transaction; 1941 } else { 1942 spin_unlock(&root->fs_info->trans_lock); 1943 } 1944 } else { 1945 spin_unlock(&root->fs_info->trans_lock); 1946 } 1947 1948 extwriter_counter_dec(cur_trans, trans->type); 1949 1950 ret = btrfs_start_delalloc_flush(root->fs_info); 1951 if (ret) 1952 goto cleanup_transaction; 1953 1954 ret = btrfs_run_delayed_items(trans, root); 1955 if (ret) 1956 goto cleanup_transaction; 1957 1958 wait_event(cur_trans->writer_wait, 1959 extwriter_counter_read(cur_trans) == 0); 1960 1961 /* some pending stuffs might be added after the previous flush. */ 1962 ret = btrfs_run_delayed_items(trans, root); 1963 if (ret) 1964 goto cleanup_transaction; 1965 1966 btrfs_wait_delalloc_flush(root->fs_info); 1967 1968 btrfs_wait_pending_ordered(cur_trans); 1969 1970 btrfs_scrub_pause(root); 1971 /* 1972 * Ok now we need to make sure to block out any other joins while we 1973 * commit the transaction. We could have started a join before setting 1974 * COMMIT_DOING so make sure to wait for num_writers to == 1 again. 1975 */ 1976 spin_lock(&root->fs_info->trans_lock); 1977 cur_trans->state = TRANS_STATE_COMMIT_DOING; 1978 spin_unlock(&root->fs_info->trans_lock); 1979 wait_event(cur_trans->writer_wait, 1980 atomic_read(&cur_trans->num_writers) == 1); 1981 1982 /* ->aborted might be set after the previous check, so check it */ 1983 if (unlikely(ACCESS_ONCE(cur_trans->aborted))) { 1984 ret = cur_trans->aborted; 1985 goto scrub_continue; 1986 } 1987 /* 1988 * the reloc mutex makes sure that we stop 1989 * the balancing code from coming in and moving 1990 * extents around in the middle of the commit 1991 */ 1992 mutex_lock(&root->fs_info->reloc_mutex); 1993 1994 /* 1995 * We needn't worry about the delayed items because we will 1996 * deal with them in create_pending_snapshot(), which is the 1997 * core function of the snapshot creation. 1998 */ 1999 ret = create_pending_snapshots(trans, root->fs_info); 2000 if (ret) { 2001 mutex_unlock(&root->fs_info->reloc_mutex); 2002 goto scrub_continue; 2003 } 2004 2005 /* 2006 * We insert the dir indexes of the snapshots and update the inode 2007 * of the snapshots' parents after the snapshot creation, so there 2008 * are some delayed items which are not dealt with. Now deal with 2009 * them. 2010 * 2011 * We needn't worry that this operation will corrupt the snapshots, 2012 * because all the tree which are snapshoted will be forced to COW 2013 * the nodes and leaves. 2014 */ 2015 ret = btrfs_run_delayed_items(trans, root); 2016 if (ret) { 2017 mutex_unlock(&root->fs_info->reloc_mutex); 2018 goto scrub_continue; 2019 } 2020 2021 ret = btrfs_run_delayed_refs(trans, root, (unsigned long)-1); 2022 if (ret) { 2023 mutex_unlock(&root->fs_info->reloc_mutex); 2024 goto scrub_continue; 2025 } 2026 2027 /* Reocrd old roots for later qgroup accounting */ 2028 ret = btrfs_qgroup_prepare_account_extents(trans, root->fs_info); 2029 if (ret) { 2030 mutex_unlock(&root->fs_info->reloc_mutex); 2031 goto scrub_continue; 2032 } 2033 2034 /* 2035 * make sure none of the code above managed to slip in a 2036 * delayed item 2037 */ 2038 btrfs_assert_delayed_root_empty(root); 2039 2040 WARN_ON(cur_trans != trans->transaction); 2041 2042 /* btrfs_commit_tree_roots is responsible for getting the 2043 * various roots consistent with each other. Every pointer 2044 * in the tree of tree roots has to point to the most up to date 2045 * root for every subvolume and other tree. So, we have to keep 2046 * the tree logging code from jumping in and changing any 2047 * of the trees. 2048 * 2049 * At this point in the commit, there can't be any tree-log 2050 * writers, but a little lower down we drop the trans mutex 2051 * and let new people in. By holding the tree_log_mutex 2052 * from now until after the super is written, we avoid races 2053 * with the tree-log code. 2054 */ 2055 mutex_lock(&root->fs_info->tree_log_mutex); 2056 2057 ret = commit_fs_roots(trans, root); 2058 if (ret) { 2059 mutex_unlock(&root->fs_info->tree_log_mutex); 2060 mutex_unlock(&root->fs_info->reloc_mutex); 2061 goto scrub_continue; 2062 } 2063 2064 /* 2065 * Since the transaction is done, we can apply the pending changes 2066 * before the next transaction. 2067 */ 2068 btrfs_apply_pending_changes(root->fs_info); 2069 2070 /* commit_fs_roots gets rid of all the tree log roots, it is now 2071 * safe to free the root of tree log roots 2072 */ 2073 btrfs_free_log_root_tree(trans, root->fs_info); 2074 2075 /* 2076 * Since fs roots are all committed, we can get a quite accurate 2077 * new_roots. So let's do quota accounting. 2078 */ 2079 ret = btrfs_qgroup_account_extents(trans, root->fs_info); 2080 if (ret < 0) { 2081 mutex_unlock(&root->fs_info->tree_log_mutex); 2082 mutex_unlock(&root->fs_info->reloc_mutex); 2083 goto scrub_continue; 2084 } 2085 2086 ret = commit_cowonly_roots(trans, root); 2087 if (ret) { 2088 mutex_unlock(&root->fs_info->tree_log_mutex); 2089 mutex_unlock(&root->fs_info->reloc_mutex); 2090 goto scrub_continue; 2091 } 2092 2093 /* 2094 * The tasks which save the space cache and inode cache may also 2095 * update ->aborted, check it. 2096 */ 2097 if (unlikely(ACCESS_ONCE(cur_trans->aborted))) { 2098 ret = cur_trans->aborted; 2099 mutex_unlock(&root->fs_info->tree_log_mutex); 2100 mutex_unlock(&root->fs_info->reloc_mutex); 2101 goto scrub_continue; 2102 } 2103 2104 btrfs_prepare_extent_commit(trans, root); 2105 2106 cur_trans = root->fs_info->running_transaction; 2107 2108 btrfs_set_root_node(&root->fs_info->tree_root->root_item, 2109 root->fs_info->tree_root->node); 2110 list_add_tail(&root->fs_info->tree_root->dirty_list, 2111 &cur_trans->switch_commits); 2112 2113 btrfs_set_root_node(&root->fs_info->chunk_root->root_item, 2114 root->fs_info->chunk_root->node); 2115 list_add_tail(&root->fs_info->chunk_root->dirty_list, 2116 &cur_trans->switch_commits); 2117 2118 switch_commit_roots(cur_trans, root->fs_info); 2119 2120 assert_qgroups_uptodate(trans); 2121 ASSERT(list_empty(&cur_trans->dirty_bgs)); 2122 ASSERT(list_empty(&cur_trans->io_bgs)); 2123 update_super_roots(root); 2124 2125 btrfs_set_super_log_root(root->fs_info->super_copy, 0); 2126 btrfs_set_super_log_root_level(root->fs_info->super_copy, 0); 2127 memcpy(root->fs_info->super_for_commit, root->fs_info->super_copy, 2128 sizeof(*root->fs_info->super_copy)); 2129 2130 btrfs_update_commit_device_size(root->fs_info); 2131 btrfs_update_commit_device_bytes_used(root, cur_trans); 2132 2133 clear_bit(BTRFS_INODE_BTREE_LOG1_ERR, &btree_ino->runtime_flags); 2134 clear_bit(BTRFS_INODE_BTREE_LOG2_ERR, &btree_ino->runtime_flags); 2135 2136 btrfs_trans_release_chunk_metadata(trans); 2137 2138 spin_lock(&root->fs_info->trans_lock); 2139 cur_trans->state = TRANS_STATE_UNBLOCKED; 2140 root->fs_info->running_transaction = NULL; 2141 spin_unlock(&root->fs_info->trans_lock); 2142 mutex_unlock(&root->fs_info->reloc_mutex); 2143 2144 wake_up(&root->fs_info->transaction_wait); 2145 2146 ret = btrfs_write_and_wait_transaction(trans, root); 2147 if (ret) { 2148 btrfs_std_error(root->fs_info, ret, 2149 "Error while writing out transaction"); 2150 mutex_unlock(&root->fs_info->tree_log_mutex); 2151 goto scrub_continue; 2152 } 2153 2154 ret = write_ctree_super(trans, root, 0); 2155 if (ret) { 2156 mutex_unlock(&root->fs_info->tree_log_mutex); 2157 goto scrub_continue; 2158 } 2159 2160 /* 2161 * the super is written, we can safely allow the tree-loggers 2162 * to go about their business 2163 */ 2164 mutex_unlock(&root->fs_info->tree_log_mutex); 2165 2166 btrfs_finish_extent_commit(trans, root); 2167 2168 if (test_bit(BTRFS_TRANS_HAVE_FREE_BGS, &cur_trans->flags)) 2169 btrfs_clear_space_info_full(root->fs_info); 2170 2171 root->fs_info->last_trans_committed = cur_trans->transid; 2172 /* 2173 * We needn't acquire the lock here because there is no other task 2174 * which can change it. 2175 */ 2176 cur_trans->state = TRANS_STATE_COMPLETED; 2177 wake_up(&cur_trans->commit_wait); 2178 2179 spin_lock(&root->fs_info->trans_lock); 2180 list_del_init(&cur_trans->list); 2181 spin_unlock(&root->fs_info->trans_lock); 2182 2183 btrfs_put_transaction(cur_trans); 2184 btrfs_put_transaction(cur_trans); 2185 2186 if (trans->type & __TRANS_FREEZABLE) 2187 sb_end_intwrite(root->fs_info->sb); 2188 2189 trace_btrfs_transaction_commit(root); 2190 2191 btrfs_scrub_continue(root); 2192 2193 if (current->journal_info == trans) 2194 current->journal_info = NULL; 2195 2196 kmem_cache_free(btrfs_trans_handle_cachep, trans); 2197 2198 if (current != root->fs_info->transaction_kthread && 2199 current != root->fs_info->cleaner_kthread) 2200 btrfs_run_delayed_iputs(root); 2201 2202 return ret; 2203 2204 scrub_continue: 2205 btrfs_scrub_continue(root); 2206 cleanup_transaction: 2207 btrfs_trans_release_metadata(trans, root); 2208 btrfs_trans_release_chunk_metadata(trans); 2209 trans->block_rsv = NULL; 2210 btrfs_warn(root->fs_info, "Skipping commit of aborted transaction."); 2211 if (current->journal_info == trans) 2212 current->journal_info = NULL; 2213 cleanup_transaction(trans, root, ret); 2214 2215 return ret; 2216 } 2217 2218 /* 2219 * return < 0 if error 2220 * 0 if there are no more dead_roots at the time of call 2221 * 1 there are more to be processed, call me again 2222 * 2223 * The return value indicates there are certainly more snapshots to delete, but 2224 * if there comes a new one during processing, it may return 0. We don't mind, 2225 * because btrfs_commit_super will poke cleaner thread and it will process it a 2226 * few seconds later. 2227 */ 2228 int btrfs_clean_one_deleted_snapshot(struct btrfs_root *root) 2229 { 2230 int ret; 2231 struct btrfs_fs_info *fs_info = root->fs_info; 2232 2233 spin_lock(&fs_info->trans_lock); 2234 if (list_empty(&fs_info->dead_roots)) { 2235 spin_unlock(&fs_info->trans_lock); 2236 return 0; 2237 } 2238 root = list_first_entry(&fs_info->dead_roots, 2239 struct btrfs_root, root_list); 2240 list_del_init(&root->root_list); 2241 spin_unlock(&fs_info->trans_lock); 2242 2243 pr_debug("BTRFS: cleaner removing %llu\n", root->objectid); 2244 2245 btrfs_kill_all_delayed_nodes(root); 2246 2247 if (btrfs_header_backref_rev(root->node) < 2248 BTRFS_MIXED_BACKREF_REV) 2249 ret = btrfs_drop_snapshot(root, NULL, 0, 0); 2250 else 2251 ret = btrfs_drop_snapshot(root, NULL, 1, 0); 2252 2253 return (ret < 0) ? 0 : 1; 2254 } 2255 2256 void btrfs_apply_pending_changes(struct btrfs_fs_info *fs_info) 2257 { 2258 unsigned long prev; 2259 unsigned long bit; 2260 2261 prev = xchg(&fs_info->pending_changes, 0); 2262 if (!prev) 2263 return; 2264 2265 bit = 1 << BTRFS_PENDING_SET_INODE_MAP_CACHE; 2266 if (prev & bit) 2267 btrfs_set_opt(fs_info->mount_opt, INODE_MAP_CACHE); 2268 prev &= ~bit; 2269 2270 bit = 1 << BTRFS_PENDING_CLEAR_INODE_MAP_CACHE; 2271 if (prev & bit) 2272 btrfs_clear_opt(fs_info->mount_opt, INODE_MAP_CACHE); 2273 prev &= ~bit; 2274 2275 bit = 1 << BTRFS_PENDING_COMMIT; 2276 if (prev & bit) 2277 btrfs_debug(fs_info, "pending commit done"); 2278 prev &= ~bit; 2279 2280 if (prev) 2281 btrfs_warn(fs_info, 2282 "unknown pending changes left 0x%lx, ignoring", prev); 2283 } 2284