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 btrfs_err(transaction->fs_info, 69 "pending csums is %llu", 70 transaction->delayed_refs.pending_csums); 71 while (!list_empty(&transaction->pending_chunks)) { 72 struct extent_map *em; 73 74 em = list_first_entry(&transaction->pending_chunks, 75 struct extent_map, list); 76 list_del_init(&em->list); 77 free_extent_map(em); 78 } 79 /* 80 * If any block groups are found in ->deleted_bgs then it's 81 * because the transaction was aborted and a commit did not 82 * happen (things failed before writing the new superblock 83 * and calling btrfs_finish_extent_commit()), so we can not 84 * discard the physical locations of the block groups. 85 */ 86 while (!list_empty(&transaction->deleted_bgs)) { 87 struct btrfs_block_group_cache *cache; 88 89 cache = list_first_entry(&transaction->deleted_bgs, 90 struct btrfs_block_group_cache, 91 bg_list); 92 list_del_init(&cache->bg_list); 93 btrfs_put_block_group_trimming(cache); 94 btrfs_put_block_group(cache); 95 } 96 kmem_cache_free(btrfs_transaction_cachep, transaction); 97 } 98 } 99 100 static void clear_btree_io_tree(struct extent_io_tree *tree) 101 { 102 spin_lock(&tree->lock); 103 /* 104 * Do a single barrier for the waitqueue_active check here, the state 105 * of the waitqueue should not change once clear_btree_io_tree is 106 * called. 107 */ 108 smp_mb(); 109 while (!RB_EMPTY_ROOT(&tree->state)) { 110 struct rb_node *node; 111 struct extent_state *state; 112 113 node = rb_first(&tree->state); 114 state = rb_entry(node, struct extent_state, rb_node); 115 rb_erase(&state->rb_node, &tree->state); 116 RB_CLEAR_NODE(&state->rb_node); 117 /* 118 * btree io trees aren't supposed to have tasks waiting for 119 * changes in the flags of extent states ever. 120 */ 121 ASSERT(!waitqueue_active(&state->wq)); 122 free_extent_state(state); 123 124 cond_resched_lock(&tree->lock); 125 } 126 spin_unlock(&tree->lock); 127 } 128 129 static noinline void switch_commit_roots(struct btrfs_transaction *trans, 130 struct btrfs_fs_info *fs_info) 131 { 132 struct btrfs_root *root, *tmp; 133 134 down_write(&fs_info->commit_root_sem); 135 list_for_each_entry_safe(root, tmp, &trans->switch_commits, 136 dirty_list) { 137 list_del_init(&root->dirty_list); 138 free_extent_buffer(root->commit_root); 139 root->commit_root = btrfs_root_node(root); 140 if (is_fstree(root->objectid)) 141 btrfs_unpin_free_ino(root); 142 clear_btree_io_tree(&root->dirty_log_pages); 143 } 144 145 /* We can free old roots now. */ 146 spin_lock(&trans->dropped_roots_lock); 147 while (!list_empty(&trans->dropped_roots)) { 148 root = list_first_entry(&trans->dropped_roots, 149 struct btrfs_root, root_list); 150 list_del_init(&root->root_list); 151 spin_unlock(&trans->dropped_roots_lock); 152 btrfs_drop_and_free_fs_root(fs_info, root); 153 spin_lock(&trans->dropped_roots_lock); 154 } 155 spin_unlock(&trans->dropped_roots_lock); 156 up_write(&fs_info->commit_root_sem); 157 } 158 159 static inline void extwriter_counter_inc(struct btrfs_transaction *trans, 160 unsigned int type) 161 { 162 if (type & TRANS_EXTWRITERS) 163 atomic_inc(&trans->num_extwriters); 164 } 165 166 static inline void extwriter_counter_dec(struct btrfs_transaction *trans, 167 unsigned int type) 168 { 169 if (type & TRANS_EXTWRITERS) 170 atomic_dec(&trans->num_extwriters); 171 } 172 173 static inline void extwriter_counter_init(struct btrfs_transaction *trans, 174 unsigned int type) 175 { 176 atomic_set(&trans->num_extwriters, ((type & TRANS_EXTWRITERS) ? 1 : 0)); 177 } 178 179 static inline int extwriter_counter_read(struct btrfs_transaction *trans) 180 { 181 return atomic_read(&trans->num_extwriters); 182 } 183 184 /* 185 * either allocate a new transaction or hop into the existing one 186 */ 187 static noinline int join_transaction(struct btrfs_fs_info *fs_info, 188 unsigned int type) 189 { 190 struct btrfs_transaction *cur_trans; 191 192 spin_lock(&fs_info->trans_lock); 193 loop: 194 /* The file system has been taken offline. No new transactions. */ 195 if (test_bit(BTRFS_FS_STATE_ERROR, &fs_info->fs_state)) { 196 spin_unlock(&fs_info->trans_lock); 197 return -EROFS; 198 } 199 200 cur_trans = fs_info->running_transaction; 201 if (cur_trans) { 202 if (cur_trans->aborted) { 203 spin_unlock(&fs_info->trans_lock); 204 return cur_trans->aborted; 205 } 206 if (btrfs_blocked_trans_types[cur_trans->state] & type) { 207 spin_unlock(&fs_info->trans_lock); 208 return -EBUSY; 209 } 210 atomic_inc(&cur_trans->use_count); 211 atomic_inc(&cur_trans->num_writers); 212 extwriter_counter_inc(cur_trans, type); 213 spin_unlock(&fs_info->trans_lock); 214 return 0; 215 } 216 spin_unlock(&fs_info->trans_lock); 217 218 /* 219 * If we are ATTACH, we just want to catch the current transaction, 220 * and commit it. If there is no transaction, just return ENOENT. 221 */ 222 if (type == TRANS_ATTACH) 223 return -ENOENT; 224 225 /* 226 * JOIN_NOLOCK only happens during the transaction commit, so 227 * it is impossible that ->running_transaction is NULL 228 */ 229 BUG_ON(type == TRANS_JOIN_NOLOCK); 230 231 cur_trans = kmem_cache_alloc(btrfs_transaction_cachep, GFP_NOFS); 232 if (!cur_trans) 233 return -ENOMEM; 234 235 spin_lock(&fs_info->trans_lock); 236 if (fs_info->running_transaction) { 237 /* 238 * someone started a transaction after we unlocked. Make sure 239 * to redo the checks above 240 */ 241 kmem_cache_free(btrfs_transaction_cachep, cur_trans); 242 goto loop; 243 } else if (test_bit(BTRFS_FS_STATE_ERROR, &fs_info->fs_state)) { 244 spin_unlock(&fs_info->trans_lock); 245 kmem_cache_free(btrfs_transaction_cachep, cur_trans); 246 return -EROFS; 247 } 248 249 cur_trans->fs_info = fs_info; 250 atomic_set(&cur_trans->num_writers, 1); 251 extwriter_counter_init(cur_trans, type); 252 init_waitqueue_head(&cur_trans->writer_wait); 253 init_waitqueue_head(&cur_trans->commit_wait); 254 init_waitqueue_head(&cur_trans->pending_wait); 255 cur_trans->state = TRANS_STATE_RUNNING; 256 /* 257 * One for this trans handle, one so it will live on until we 258 * commit the transaction. 259 */ 260 atomic_set(&cur_trans->use_count, 2); 261 atomic_set(&cur_trans->pending_ordered, 0); 262 cur_trans->flags = 0; 263 cur_trans->start_time = get_seconds(); 264 265 memset(&cur_trans->delayed_refs, 0, sizeof(cur_trans->delayed_refs)); 266 267 cur_trans->delayed_refs.href_root = RB_ROOT; 268 cur_trans->delayed_refs.dirty_extent_root = RB_ROOT; 269 atomic_set(&cur_trans->delayed_refs.num_entries, 0); 270 271 /* 272 * although the tree mod log is per file system and not per transaction, 273 * the log must never go across transaction boundaries. 274 */ 275 smp_mb(); 276 if (!list_empty(&fs_info->tree_mod_seq_list)) 277 WARN(1, KERN_ERR "BTRFS: tree_mod_seq_list not empty when creating a fresh transaction\n"); 278 if (!RB_EMPTY_ROOT(&fs_info->tree_mod_log)) 279 WARN(1, KERN_ERR "BTRFS: tree_mod_log rb tree not empty when 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 int force) 316 { 317 struct btrfs_fs_info *fs_info = root->fs_info; 318 319 if ((test_bit(BTRFS_ROOT_REF_COWS, &root->state) && 320 root->last_trans < trans->transid) || force) { 321 WARN_ON(root == fs_info->extent_root); 322 WARN_ON(root->commit_root != root->node); 323 324 /* 325 * see below for IN_TRANS_SETUP usage rules 326 * we have the reloc mutex held now, so there 327 * is only one writer in this function 328 */ 329 set_bit(BTRFS_ROOT_IN_TRANS_SETUP, &root->state); 330 331 /* make sure readers find IN_TRANS_SETUP before 332 * they find our root->last_trans update 333 */ 334 smp_wmb(); 335 336 spin_lock(&fs_info->fs_roots_radix_lock); 337 if (root->last_trans == trans->transid && !force) { 338 spin_unlock(&fs_info->fs_roots_radix_lock); 339 return 0; 340 } 341 radix_tree_tag_set(&fs_info->fs_roots_radix, 342 (unsigned long)root->root_key.objectid, 343 BTRFS_ROOT_TRANS_TAG); 344 spin_unlock(&fs_info->fs_roots_radix_lock); 345 root->last_trans = trans->transid; 346 347 /* this is pretty tricky. We don't want to 348 * take the relocation lock in btrfs_record_root_in_trans 349 * unless we're really doing the first setup for this root in 350 * this transaction. 351 * 352 * Normally we'd use root->last_trans as a flag to decide 353 * if we want to take the expensive mutex. 354 * 355 * But, we have to set root->last_trans before we 356 * init the relocation root, otherwise, we trip over warnings 357 * in ctree.c. The solution used here is to flag ourselves 358 * with root IN_TRANS_SETUP. When this is 1, we're still 359 * fixing up the reloc trees and everyone must wait. 360 * 361 * When this is zero, they can trust root->last_trans and fly 362 * through btrfs_record_root_in_trans without having to take the 363 * lock. smp_wmb() makes sure that all the writes above are 364 * done before we pop in the zero below 365 */ 366 btrfs_init_reloc_root(trans, root); 367 smp_mb__before_atomic(); 368 clear_bit(BTRFS_ROOT_IN_TRANS_SETUP, &root->state); 369 } 370 return 0; 371 } 372 373 374 void btrfs_add_dropped_root(struct btrfs_trans_handle *trans, 375 struct btrfs_root *root) 376 { 377 struct btrfs_fs_info *fs_info = root->fs_info; 378 struct btrfs_transaction *cur_trans = trans->transaction; 379 380 /* Add ourselves to the transaction dropped list */ 381 spin_lock(&cur_trans->dropped_roots_lock); 382 list_add_tail(&root->root_list, &cur_trans->dropped_roots); 383 spin_unlock(&cur_trans->dropped_roots_lock); 384 385 /* Make sure we don't try to update the root at commit time */ 386 spin_lock(&fs_info->fs_roots_radix_lock); 387 radix_tree_tag_clear(&fs_info->fs_roots_radix, 388 (unsigned long)root->root_key.objectid, 389 BTRFS_ROOT_TRANS_TAG); 390 spin_unlock(&fs_info->fs_roots_radix_lock); 391 } 392 393 int btrfs_record_root_in_trans(struct btrfs_trans_handle *trans, 394 struct btrfs_root *root) 395 { 396 struct btrfs_fs_info *fs_info = root->fs_info; 397 398 if (!test_bit(BTRFS_ROOT_REF_COWS, &root->state)) 399 return 0; 400 401 /* 402 * see record_root_in_trans for comments about IN_TRANS_SETUP usage 403 * and barriers 404 */ 405 smp_rmb(); 406 if (root->last_trans == trans->transid && 407 !test_bit(BTRFS_ROOT_IN_TRANS_SETUP, &root->state)) 408 return 0; 409 410 mutex_lock(&fs_info->reloc_mutex); 411 record_root_in_trans(trans, root, 0); 412 mutex_unlock(&fs_info->reloc_mutex); 413 414 return 0; 415 } 416 417 static inline int is_transaction_blocked(struct btrfs_transaction *trans) 418 { 419 return (trans->state >= TRANS_STATE_BLOCKED && 420 trans->state < TRANS_STATE_UNBLOCKED && 421 !trans->aborted); 422 } 423 424 /* wait for commit against the current transaction to become unblocked 425 * when this is done, it is safe to start a new transaction, but the current 426 * transaction might not be fully on disk. 427 */ 428 static void wait_current_trans(struct btrfs_fs_info *fs_info) 429 { 430 struct btrfs_transaction *cur_trans; 431 432 spin_lock(&fs_info->trans_lock); 433 cur_trans = fs_info->running_transaction; 434 if (cur_trans && is_transaction_blocked(cur_trans)) { 435 atomic_inc(&cur_trans->use_count); 436 spin_unlock(&fs_info->trans_lock); 437 438 wait_event(fs_info->transaction_wait, 439 cur_trans->state >= TRANS_STATE_UNBLOCKED || 440 cur_trans->aborted); 441 btrfs_put_transaction(cur_trans); 442 } else { 443 spin_unlock(&fs_info->trans_lock); 444 } 445 } 446 447 static int may_wait_transaction(struct btrfs_fs_info *fs_info, int type) 448 { 449 if (test_bit(BTRFS_FS_LOG_RECOVERING, &fs_info->flags)) 450 return 0; 451 452 if (type == TRANS_USERSPACE) 453 return 1; 454 455 if (type == TRANS_START && 456 !atomic_read(&fs_info->open_ioctl_trans)) 457 return 1; 458 459 return 0; 460 } 461 462 static inline bool need_reserve_reloc_root(struct btrfs_root *root) 463 { 464 struct btrfs_fs_info *fs_info = root->fs_info; 465 466 if (!fs_info->reloc_ctl || 467 !test_bit(BTRFS_ROOT_REF_COWS, &root->state) || 468 root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID || 469 root->reloc_root) 470 return false; 471 472 return true; 473 } 474 475 static struct btrfs_trans_handle * 476 start_transaction(struct btrfs_root *root, unsigned int num_items, 477 unsigned int type, enum btrfs_reserve_flush_enum flush, 478 bool enforce_qgroups) 479 { 480 struct btrfs_fs_info *fs_info = root->fs_info; 481 482 struct btrfs_trans_handle *h; 483 struct btrfs_transaction *cur_trans; 484 u64 num_bytes = 0; 485 u64 qgroup_reserved = 0; 486 bool reloc_reserved = false; 487 int ret; 488 489 /* Send isn't supposed to start transactions. */ 490 ASSERT(current->journal_info != BTRFS_SEND_TRANS_STUB); 491 492 if (test_bit(BTRFS_FS_STATE_ERROR, &fs_info->fs_state)) 493 return ERR_PTR(-EROFS); 494 495 if (current->journal_info) { 496 WARN_ON(type & TRANS_EXTWRITERS); 497 h = current->journal_info; 498 h->use_count++; 499 WARN_ON(h->use_count > 2); 500 h->orig_rsv = h->block_rsv; 501 h->block_rsv = NULL; 502 goto got_it; 503 } 504 505 /* 506 * Do the reservation before we join the transaction so we can do all 507 * the appropriate flushing if need be. 508 */ 509 if (num_items && root != fs_info->chunk_root) { 510 qgroup_reserved = num_items * fs_info->nodesize; 511 ret = btrfs_qgroup_reserve_meta(root, qgroup_reserved, 512 enforce_qgroups); 513 if (ret) 514 return ERR_PTR(ret); 515 516 num_bytes = btrfs_calc_trans_metadata_size(fs_info, num_items); 517 /* 518 * Do the reservation for the relocation root creation 519 */ 520 if (need_reserve_reloc_root(root)) { 521 num_bytes += fs_info->nodesize; 522 reloc_reserved = true; 523 } 524 525 ret = btrfs_block_rsv_add(root, &fs_info->trans_block_rsv, 526 num_bytes, flush); 527 if (ret) 528 goto reserve_fail; 529 } 530 again: 531 h = kmem_cache_zalloc(btrfs_trans_handle_cachep, GFP_NOFS); 532 if (!h) { 533 ret = -ENOMEM; 534 goto alloc_fail; 535 } 536 537 /* 538 * If we are JOIN_NOLOCK we're already committing a transaction and 539 * waiting on this guy, so we don't need to do the sb_start_intwrite 540 * because we're already holding a ref. We need this because we could 541 * have raced in and did an fsync() on a file which can kick a commit 542 * and then we deadlock with somebody doing a freeze. 543 * 544 * If we are ATTACH, it means we just want to catch the current 545 * transaction and commit it, so we needn't do sb_start_intwrite(). 546 */ 547 if (type & __TRANS_FREEZABLE) 548 sb_start_intwrite(fs_info->sb); 549 550 if (may_wait_transaction(fs_info, type)) 551 wait_current_trans(fs_info); 552 553 do { 554 ret = join_transaction(fs_info, type); 555 if (ret == -EBUSY) { 556 wait_current_trans(fs_info); 557 if (unlikely(type == TRANS_ATTACH)) 558 ret = -ENOENT; 559 } 560 } while (ret == -EBUSY); 561 562 if (ret < 0) 563 goto join_fail; 564 565 cur_trans = fs_info->running_transaction; 566 567 h->transid = cur_trans->transid; 568 h->transaction = cur_trans; 569 h->root = root; 570 h->use_count = 1; 571 h->fs_info = root->fs_info; 572 573 h->type = type; 574 h->can_flush_pending_bgs = true; 575 INIT_LIST_HEAD(&h->qgroup_ref_list); 576 INIT_LIST_HEAD(&h->new_bgs); 577 578 smp_mb(); 579 if (cur_trans->state >= TRANS_STATE_BLOCKED && 580 may_wait_transaction(fs_info, type)) { 581 current->journal_info = h; 582 btrfs_commit_transaction(h); 583 goto again; 584 } 585 586 if (num_bytes) { 587 trace_btrfs_space_reservation(fs_info, "transaction", 588 h->transid, num_bytes, 1); 589 h->block_rsv = &fs_info->trans_block_rsv; 590 h->bytes_reserved = num_bytes; 591 h->reloc_reserved = reloc_reserved; 592 } 593 594 got_it: 595 btrfs_record_root_in_trans(h, root); 596 597 if (!current->journal_info && type != TRANS_USERSPACE) 598 current->journal_info = h; 599 return h; 600 601 join_fail: 602 if (type & __TRANS_FREEZABLE) 603 sb_end_intwrite(fs_info->sb); 604 kmem_cache_free(btrfs_trans_handle_cachep, h); 605 alloc_fail: 606 if (num_bytes) 607 btrfs_block_rsv_release(fs_info, &fs_info->trans_block_rsv, 608 num_bytes); 609 reserve_fail: 610 btrfs_qgroup_free_meta(root, qgroup_reserved); 611 return ERR_PTR(ret); 612 } 613 614 struct btrfs_trans_handle *btrfs_start_transaction(struct btrfs_root *root, 615 unsigned int num_items) 616 { 617 return start_transaction(root, num_items, TRANS_START, 618 BTRFS_RESERVE_FLUSH_ALL, true); 619 } 620 621 struct btrfs_trans_handle *btrfs_start_transaction_fallback_global_rsv( 622 struct btrfs_root *root, 623 unsigned int num_items, 624 int min_factor) 625 { 626 struct btrfs_fs_info *fs_info = root->fs_info; 627 struct btrfs_trans_handle *trans; 628 u64 num_bytes; 629 int ret; 630 631 /* 632 * We have two callers: unlink and block group removal. The 633 * former should succeed even if we will temporarily exceed 634 * quota and the latter operates on the extent root so 635 * qgroup enforcement is ignored anyway. 636 */ 637 trans = start_transaction(root, num_items, TRANS_START, 638 BTRFS_RESERVE_FLUSH_ALL, false); 639 if (!IS_ERR(trans) || PTR_ERR(trans) != -ENOSPC) 640 return trans; 641 642 trans = btrfs_start_transaction(root, 0); 643 if (IS_ERR(trans)) 644 return trans; 645 646 num_bytes = btrfs_calc_trans_metadata_size(fs_info, num_items); 647 ret = btrfs_cond_migrate_bytes(fs_info, &fs_info->trans_block_rsv, 648 num_bytes, min_factor); 649 if (ret) { 650 btrfs_end_transaction(trans); 651 return ERR_PTR(ret); 652 } 653 654 trans->block_rsv = &fs_info->trans_block_rsv; 655 trans->bytes_reserved = num_bytes; 656 trace_btrfs_space_reservation(fs_info, "transaction", 657 trans->transid, num_bytes, 1); 658 659 return trans; 660 } 661 662 struct btrfs_trans_handle *btrfs_start_transaction_lflush( 663 struct btrfs_root *root, 664 unsigned int num_items) 665 { 666 return start_transaction(root, num_items, TRANS_START, 667 BTRFS_RESERVE_FLUSH_LIMIT, true); 668 } 669 670 struct btrfs_trans_handle *btrfs_join_transaction(struct btrfs_root *root) 671 { 672 return start_transaction(root, 0, TRANS_JOIN, BTRFS_RESERVE_NO_FLUSH, 673 true); 674 } 675 676 struct btrfs_trans_handle *btrfs_join_transaction_nolock(struct btrfs_root *root) 677 { 678 return start_transaction(root, 0, TRANS_JOIN_NOLOCK, 679 BTRFS_RESERVE_NO_FLUSH, true); 680 } 681 682 struct btrfs_trans_handle *btrfs_start_ioctl_transaction(struct btrfs_root *root) 683 { 684 return start_transaction(root, 0, TRANS_USERSPACE, 685 BTRFS_RESERVE_NO_FLUSH, true); 686 } 687 688 /* 689 * btrfs_attach_transaction() - catch the running transaction 690 * 691 * It is used when we want to commit the current the transaction, but 692 * don't want to start a new one. 693 * 694 * Note: If this function return -ENOENT, it just means there is no 695 * running transaction. But it is possible that the inactive transaction 696 * is still in the memory, not fully on disk. If you hope there is no 697 * inactive transaction in the fs when -ENOENT is returned, you should 698 * invoke 699 * btrfs_attach_transaction_barrier() 700 */ 701 struct btrfs_trans_handle *btrfs_attach_transaction(struct btrfs_root *root) 702 { 703 return start_transaction(root, 0, TRANS_ATTACH, 704 BTRFS_RESERVE_NO_FLUSH, true); 705 } 706 707 /* 708 * btrfs_attach_transaction_barrier() - catch the running transaction 709 * 710 * It is similar to the above function, the differentia is this one 711 * will wait for all the inactive transactions until they fully 712 * complete. 713 */ 714 struct btrfs_trans_handle * 715 btrfs_attach_transaction_barrier(struct btrfs_root *root) 716 { 717 struct btrfs_trans_handle *trans; 718 719 trans = start_transaction(root, 0, TRANS_ATTACH, 720 BTRFS_RESERVE_NO_FLUSH, true); 721 if (IS_ERR(trans) && PTR_ERR(trans) == -ENOENT) 722 btrfs_wait_for_commit(root->fs_info, 0); 723 724 return trans; 725 } 726 727 /* wait for a transaction commit to be fully complete */ 728 static noinline void wait_for_commit(struct btrfs_transaction *commit) 729 { 730 wait_event(commit->commit_wait, commit->state == TRANS_STATE_COMPLETED); 731 } 732 733 int btrfs_wait_for_commit(struct btrfs_fs_info *fs_info, u64 transid) 734 { 735 struct btrfs_transaction *cur_trans = NULL, *t; 736 int ret = 0; 737 738 if (transid) { 739 if (transid <= fs_info->last_trans_committed) 740 goto out; 741 742 /* find specified transaction */ 743 spin_lock(&fs_info->trans_lock); 744 list_for_each_entry(t, &fs_info->trans_list, list) { 745 if (t->transid == transid) { 746 cur_trans = t; 747 atomic_inc(&cur_trans->use_count); 748 ret = 0; 749 break; 750 } 751 if (t->transid > transid) { 752 ret = 0; 753 break; 754 } 755 } 756 spin_unlock(&fs_info->trans_lock); 757 758 /* 759 * The specified transaction doesn't exist, or we 760 * raced with btrfs_commit_transaction 761 */ 762 if (!cur_trans) { 763 if (transid > fs_info->last_trans_committed) 764 ret = -EINVAL; 765 goto out; 766 } 767 } else { 768 /* find newest transaction that is committing | committed */ 769 spin_lock(&fs_info->trans_lock); 770 list_for_each_entry_reverse(t, &fs_info->trans_list, 771 list) { 772 if (t->state >= TRANS_STATE_COMMIT_START) { 773 if (t->state == TRANS_STATE_COMPLETED) 774 break; 775 cur_trans = t; 776 atomic_inc(&cur_trans->use_count); 777 break; 778 } 779 } 780 spin_unlock(&fs_info->trans_lock); 781 if (!cur_trans) 782 goto out; /* nothing committing|committed */ 783 } 784 785 wait_for_commit(cur_trans); 786 btrfs_put_transaction(cur_trans); 787 out: 788 return ret; 789 } 790 791 void btrfs_throttle(struct btrfs_fs_info *fs_info) 792 { 793 if (!atomic_read(&fs_info->open_ioctl_trans)) 794 wait_current_trans(fs_info); 795 } 796 797 static int should_end_transaction(struct btrfs_trans_handle *trans) 798 { 799 struct btrfs_fs_info *fs_info = trans->fs_info; 800 801 if (fs_info->global_block_rsv.space_info->full && 802 btrfs_check_space_for_delayed_refs(trans, fs_info)) 803 return 1; 804 805 return !!btrfs_block_rsv_check(&fs_info->global_block_rsv, 5); 806 } 807 808 int btrfs_should_end_transaction(struct btrfs_trans_handle *trans) 809 { 810 struct btrfs_transaction *cur_trans = trans->transaction; 811 struct btrfs_fs_info *fs_info = trans->fs_info; 812 int updates; 813 int err; 814 815 smp_mb(); 816 if (cur_trans->state >= TRANS_STATE_BLOCKED || 817 cur_trans->delayed_refs.flushing) 818 return 1; 819 820 updates = trans->delayed_ref_updates; 821 trans->delayed_ref_updates = 0; 822 if (updates) { 823 err = btrfs_run_delayed_refs(trans, fs_info, updates * 2); 824 if (err) /* Error code will also eval true */ 825 return err; 826 } 827 828 return should_end_transaction(trans); 829 } 830 831 static int __btrfs_end_transaction(struct btrfs_trans_handle *trans, 832 int throttle) 833 { 834 struct btrfs_fs_info *info = trans->fs_info; 835 struct btrfs_transaction *cur_trans = trans->transaction; 836 u64 transid = trans->transid; 837 unsigned long cur = trans->delayed_ref_updates; 838 int lock = (trans->type != TRANS_JOIN_NOLOCK); 839 int err = 0; 840 int must_run_delayed_refs = 0; 841 842 if (trans->use_count > 1) { 843 trans->use_count--; 844 trans->block_rsv = trans->orig_rsv; 845 return 0; 846 } 847 848 btrfs_trans_release_metadata(trans, info); 849 trans->block_rsv = NULL; 850 851 if (!list_empty(&trans->new_bgs)) 852 btrfs_create_pending_block_groups(trans, info); 853 854 trans->delayed_ref_updates = 0; 855 if (!trans->sync) { 856 must_run_delayed_refs = 857 btrfs_should_throttle_delayed_refs(trans, info); 858 cur = max_t(unsigned long, cur, 32); 859 860 /* 861 * don't make the caller wait if they are from a NOLOCK 862 * or ATTACH transaction, it will deadlock with commit 863 */ 864 if (must_run_delayed_refs == 1 && 865 (trans->type & (__TRANS_JOIN_NOLOCK | __TRANS_ATTACH))) 866 must_run_delayed_refs = 2; 867 } 868 869 btrfs_trans_release_metadata(trans, info); 870 trans->block_rsv = NULL; 871 872 if (!list_empty(&trans->new_bgs)) 873 btrfs_create_pending_block_groups(trans, info); 874 875 btrfs_trans_release_chunk_metadata(trans); 876 877 if (lock && !atomic_read(&info->open_ioctl_trans) && 878 should_end_transaction(trans) && 879 READ_ONCE(cur_trans->state) == TRANS_STATE_RUNNING) { 880 spin_lock(&info->trans_lock); 881 if (cur_trans->state == TRANS_STATE_RUNNING) 882 cur_trans->state = TRANS_STATE_BLOCKED; 883 spin_unlock(&info->trans_lock); 884 } 885 886 if (lock && READ_ONCE(cur_trans->state) == TRANS_STATE_BLOCKED) { 887 if (throttle) 888 return btrfs_commit_transaction(trans); 889 else 890 wake_up_process(info->transaction_kthread); 891 } 892 893 if (trans->type & __TRANS_FREEZABLE) 894 sb_end_intwrite(info->sb); 895 896 WARN_ON(cur_trans != info->running_transaction); 897 WARN_ON(atomic_read(&cur_trans->num_writers) < 1); 898 atomic_dec(&cur_trans->num_writers); 899 extwriter_counter_dec(cur_trans, trans->type); 900 901 /* 902 * Make sure counter is updated before we wake up waiters. 903 */ 904 smp_mb(); 905 if (waitqueue_active(&cur_trans->writer_wait)) 906 wake_up(&cur_trans->writer_wait); 907 btrfs_put_transaction(cur_trans); 908 909 if (current->journal_info == trans) 910 current->journal_info = NULL; 911 912 if (throttle) 913 btrfs_run_delayed_iputs(info); 914 915 if (trans->aborted || 916 test_bit(BTRFS_FS_STATE_ERROR, &info->fs_state)) { 917 wake_up_process(info->transaction_kthread); 918 err = -EIO; 919 } 920 assert_qgroups_uptodate(trans); 921 922 kmem_cache_free(btrfs_trans_handle_cachep, trans); 923 if (must_run_delayed_refs) { 924 btrfs_async_run_delayed_refs(info, cur, transid, 925 must_run_delayed_refs == 1); 926 } 927 return err; 928 } 929 930 int btrfs_end_transaction(struct btrfs_trans_handle *trans) 931 { 932 return __btrfs_end_transaction(trans, 0); 933 } 934 935 int btrfs_end_transaction_throttle(struct btrfs_trans_handle *trans) 936 { 937 return __btrfs_end_transaction(trans, 1); 938 } 939 940 /* 941 * when btree blocks are allocated, they have some corresponding bits set for 942 * them in one of two extent_io trees. This is used to make sure all of 943 * those extents are sent to disk but does not wait on them 944 */ 945 int btrfs_write_marked_extents(struct btrfs_fs_info *fs_info, 946 struct extent_io_tree *dirty_pages, int mark) 947 { 948 int err = 0; 949 int werr = 0; 950 struct address_space *mapping = fs_info->btree_inode->i_mapping; 951 struct extent_state *cached_state = NULL; 952 u64 start = 0; 953 u64 end; 954 955 while (!find_first_extent_bit(dirty_pages, start, &start, &end, 956 mark, &cached_state)) { 957 bool wait_writeback = false; 958 959 err = convert_extent_bit(dirty_pages, start, end, 960 EXTENT_NEED_WAIT, 961 mark, &cached_state); 962 /* 963 * convert_extent_bit can return -ENOMEM, which is most of the 964 * time a temporary error. So when it happens, ignore the error 965 * and wait for writeback of this range to finish - because we 966 * failed to set the bit EXTENT_NEED_WAIT for the range, a call 967 * to __btrfs_wait_marked_extents() would not know that 968 * writeback for this range started and therefore wouldn't 969 * wait for it to finish - we don't want to commit a 970 * superblock that points to btree nodes/leafs for which 971 * writeback hasn't finished yet (and without errors). 972 * We cleanup any entries left in the io tree when committing 973 * the transaction (through clear_btree_io_tree()). 974 */ 975 if (err == -ENOMEM) { 976 err = 0; 977 wait_writeback = true; 978 } 979 if (!err) 980 err = filemap_fdatawrite_range(mapping, start, end); 981 if (err) 982 werr = err; 983 else if (wait_writeback) 984 werr = filemap_fdatawait_range(mapping, start, end); 985 free_extent_state(cached_state); 986 cached_state = NULL; 987 cond_resched(); 988 start = end + 1; 989 } 990 return werr; 991 } 992 993 /* 994 * when btree blocks are allocated, they have some corresponding bits set for 995 * them in one of two extent_io trees. This is used to make sure all of 996 * those extents are on disk for transaction or log commit. We wait 997 * on all the pages and clear them from the dirty pages state tree 998 */ 999 static int __btrfs_wait_marked_extents(struct btrfs_fs_info *fs_info, 1000 struct extent_io_tree *dirty_pages) 1001 { 1002 int err = 0; 1003 int werr = 0; 1004 struct address_space *mapping = fs_info->btree_inode->i_mapping; 1005 struct extent_state *cached_state = NULL; 1006 u64 start = 0; 1007 u64 end; 1008 1009 while (!find_first_extent_bit(dirty_pages, start, &start, &end, 1010 EXTENT_NEED_WAIT, &cached_state)) { 1011 /* 1012 * Ignore -ENOMEM errors returned by clear_extent_bit(). 1013 * When committing the transaction, we'll remove any entries 1014 * left in the io tree. For a log commit, we don't remove them 1015 * after committing the log because the tree can be accessed 1016 * concurrently - we do it only at transaction commit time when 1017 * it's safe to do it (through clear_btree_io_tree()). 1018 */ 1019 err = clear_extent_bit(dirty_pages, start, end, 1020 EXTENT_NEED_WAIT, 1021 0, 0, &cached_state, GFP_NOFS); 1022 if (err == -ENOMEM) 1023 err = 0; 1024 if (!err) 1025 err = filemap_fdatawait_range(mapping, start, end); 1026 if (err) 1027 werr = err; 1028 free_extent_state(cached_state); 1029 cached_state = NULL; 1030 cond_resched(); 1031 start = end + 1; 1032 } 1033 if (err) 1034 werr = err; 1035 return werr; 1036 } 1037 1038 int btrfs_wait_extents(struct btrfs_fs_info *fs_info, 1039 struct extent_io_tree *dirty_pages) 1040 { 1041 bool errors = false; 1042 int err; 1043 1044 err = __btrfs_wait_marked_extents(fs_info, dirty_pages); 1045 if (test_and_clear_bit(BTRFS_FS_BTREE_ERR, &fs_info->flags)) 1046 errors = true; 1047 1048 if (errors && !err) 1049 err = -EIO; 1050 return err; 1051 } 1052 1053 int btrfs_wait_tree_log_extents(struct btrfs_root *log_root, int mark) 1054 { 1055 struct btrfs_fs_info *fs_info = log_root->fs_info; 1056 struct extent_io_tree *dirty_pages = &log_root->dirty_log_pages; 1057 bool errors = false; 1058 int err; 1059 1060 ASSERT(log_root->root_key.objectid == BTRFS_TREE_LOG_OBJECTID); 1061 1062 err = __btrfs_wait_marked_extents(fs_info, dirty_pages); 1063 if ((mark & EXTENT_DIRTY) && 1064 test_and_clear_bit(BTRFS_FS_LOG1_ERR, &fs_info->flags)) 1065 errors = true; 1066 1067 if ((mark & EXTENT_NEW) && 1068 test_and_clear_bit(BTRFS_FS_LOG2_ERR, &fs_info->flags)) 1069 errors = true; 1070 1071 if (errors && !err) 1072 err = -EIO; 1073 return err; 1074 } 1075 1076 /* 1077 * when btree blocks are allocated, they have some corresponding bits set for 1078 * them in one of two extent_io trees. This is used to make sure all of 1079 * those extents are on disk for transaction or log commit 1080 */ 1081 static int btrfs_write_and_wait_marked_extents(struct btrfs_fs_info *fs_info, 1082 struct extent_io_tree *dirty_pages, int mark) 1083 { 1084 int ret; 1085 int ret2; 1086 struct blk_plug plug; 1087 1088 blk_start_plug(&plug); 1089 ret = btrfs_write_marked_extents(fs_info, dirty_pages, mark); 1090 blk_finish_plug(&plug); 1091 ret2 = btrfs_wait_extents(fs_info, dirty_pages); 1092 1093 if (ret) 1094 return ret; 1095 if (ret2) 1096 return ret2; 1097 return 0; 1098 } 1099 1100 static int btrfs_write_and_wait_transaction(struct btrfs_trans_handle *trans, 1101 struct btrfs_fs_info *fs_info) 1102 { 1103 int ret; 1104 1105 ret = btrfs_write_and_wait_marked_extents(fs_info, 1106 &trans->transaction->dirty_pages, 1107 EXTENT_DIRTY); 1108 clear_btree_io_tree(&trans->transaction->dirty_pages); 1109 1110 return ret; 1111 } 1112 1113 /* 1114 * this is used to update the root pointer in the tree of tree roots. 1115 * 1116 * But, in the case of the extent allocation tree, updating the root 1117 * pointer may allocate blocks which may change the root of the extent 1118 * allocation tree. 1119 * 1120 * So, this loops and repeats and makes sure the cowonly root didn't 1121 * change while the root pointer was being updated in the metadata. 1122 */ 1123 static int update_cowonly_root(struct btrfs_trans_handle *trans, 1124 struct btrfs_root *root) 1125 { 1126 int ret; 1127 u64 old_root_bytenr; 1128 u64 old_root_used; 1129 struct btrfs_fs_info *fs_info = root->fs_info; 1130 struct btrfs_root *tree_root = fs_info->tree_root; 1131 1132 old_root_used = btrfs_root_used(&root->root_item); 1133 1134 while (1) { 1135 old_root_bytenr = btrfs_root_bytenr(&root->root_item); 1136 if (old_root_bytenr == root->node->start && 1137 old_root_used == btrfs_root_used(&root->root_item)) 1138 break; 1139 1140 btrfs_set_root_node(&root->root_item, root->node); 1141 ret = btrfs_update_root(trans, tree_root, 1142 &root->root_key, 1143 &root->root_item); 1144 if (ret) 1145 return ret; 1146 1147 old_root_used = btrfs_root_used(&root->root_item); 1148 } 1149 1150 return 0; 1151 } 1152 1153 /* 1154 * update all the cowonly tree roots on disk 1155 * 1156 * The error handling in this function may not be obvious. Any of the 1157 * failures will cause the file system to go offline. We still need 1158 * to clean up the delayed refs. 1159 */ 1160 static noinline int commit_cowonly_roots(struct btrfs_trans_handle *trans, 1161 struct btrfs_fs_info *fs_info) 1162 { 1163 struct list_head *dirty_bgs = &trans->transaction->dirty_bgs; 1164 struct list_head *io_bgs = &trans->transaction->io_bgs; 1165 struct list_head *next; 1166 struct extent_buffer *eb; 1167 int ret; 1168 1169 eb = btrfs_lock_root_node(fs_info->tree_root); 1170 ret = btrfs_cow_block(trans, fs_info->tree_root, eb, NULL, 1171 0, &eb); 1172 btrfs_tree_unlock(eb); 1173 free_extent_buffer(eb); 1174 1175 if (ret) 1176 return ret; 1177 1178 ret = btrfs_run_delayed_refs(trans, fs_info, (unsigned long)-1); 1179 if (ret) 1180 return ret; 1181 1182 ret = btrfs_run_dev_stats(trans, fs_info); 1183 if (ret) 1184 return ret; 1185 ret = btrfs_run_dev_replace(trans, fs_info); 1186 if (ret) 1187 return ret; 1188 ret = btrfs_run_qgroups(trans, fs_info); 1189 if (ret) 1190 return ret; 1191 1192 ret = btrfs_setup_space_cache(trans, fs_info); 1193 if (ret) 1194 return ret; 1195 1196 /* run_qgroups might have added some more refs */ 1197 ret = btrfs_run_delayed_refs(trans, fs_info, (unsigned long)-1); 1198 if (ret) 1199 return ret; 1200 again: 1201 while (!list_empty(&fs_info->dirty_cowonly_roots)) { 1202 struct btrfs_root *root; 1203 next = fs_info->dirty_cowonly_roots.next; 1204 list_del_init(next); 1205 root = list_entry(next, struct btrfs_root, dirty_list); 1206 clear_bit(BTRFS_ROOT_DIRTY, &root->state); 1207 1208 if (root != fs_info->extent_root) 1209 list_add_tail(&root->dirty_list, 1210 &trans->transaction->switch_commits); 1211 ret = update_cowonly_root(trans, root); 1212 if (ret) 1213 return ret; 1214 ret = btrfs_run_delayed_refs(trans, fs_info, (unsigned long)-1); 1215 if (ret) 1216 return ret; 1217 } 1218 1219 while (!list_empty(dirty_bgs) || !list_empty(io_bgs)) { 1220 ret = btrfs_write_dirty_block_groups(trans, fs_info); 1221 if (ret) 1222 return ret; 1223 ret = btrfs_run_delayed_refs(trans, fs_info, (unsigned long)-1); 1224 if (ret) 1225 return ret; 1226 } 1227 1228 if (!list_empty(&fs_info->dirty_cowonly_roots)) 1229 goto again; 1230 1231 list_add_tail(&fs_info->extent_root->dirty_list, 1232 &trans->transaction->switch_commits); 1233 btrfs_after_dev_replace_commit(fs_info); 1234 1235 return 0; 1236 } 1237 1238 /* 1239 * dead roots are old snapshots that need to be deleted. This allocates 1240 * a dirty root struct and adds it into the list of dead roots that need to 1241 * be deleted 1242 */ 1243 void btrfs_add_dead_root(struct btrfs_root *root) 1244 { 1245 struct btrfs_fs_info *fs_info = root->fs_info; 1246 1247 spin_lock(&fs_info->trans_lock); 1248 if (list_empty(&root->root_list)) 1249 list_add_tail(&root->root_list, &fs_info->dead_roots); 1250 spin_unlock(&fs_info->trans_lock); 1251 } 1252 1253 /* 1254 * update all the cowonly tree roots on disk 1255 */ 1256 static noinline int commit_fs_roots(struct btrfs_trans_handle *trans, 1257 struct btrfs_fs_info *fs_info) 1258 { 1259 struct btrfs_root *gang[8]; 1260 int i; 1261 int ret; 1262 int err = 0; 1263 1264 spin_lock(&fs_info->fs_roots_radix_lock); 1265 while (1) { 1266 ret = radix_tree_gang_lookup_tag(&fs_info->fs_roots_radix, 1267 (void **)gang, 0, 1268 ARRAY_SIZE(gang), 1269 BTRFS_ROOT_TRANS_TAG); 1270 if (ret == 0) 1271 break; 1272 for (i = 0; i < ret; i++) { 1273 struct btrfs_root *root = gang[i]; 1274 radix_tree_tag_clear(&fs_info->fs_roots_radix, 1275 (unsigned long)root->root_key.objectid, 1276 BTRFS_ROOT_TRANS_TAG); 1277 spin_unlock(&fs_info->fs_roots_radix_lock); 1278 1279 btrfs_free_log(trans, root); 1280 btrfs_update_reloc_root(trans, root); 1281 btrfs_orphan_commit_root(trans, root); 1282 1283 btrfs_save_ino_cache(root, trans); 1284 1285 /* see comments in should_cow_block() */ 1286 clear_bit(BTRFS_ROOT_FORCE_COW, &root->state); 1287 smp_mb__after_atomic(); 1288 1289 if (root->commit_root != root->node) { 1290 list_add_tail(&root->dirty_list, 1291 &trans->transaction->switch_commits); 1292 btrfs_set_root_node(&root->root_item, 1293 root->node); 1294 } 1295 1296 err = btrfs_update_root(trans, fs_info->tree_root, 1297 &root->root_key, 1298 &root->root_item); 1299 spin_lock(&fs_info->fs_roots_radix_lock); 1300 if (err) 1301 break; 1302 btrfs_qgroup_free_meta_all(root); 1303 } 1304 } 1305 spin_unlock(&fs_info->fs_roots_radix_lock); 1306 return err; 1307 } 1308 1309 /* 1310 * defrag a given btree. 1311 * Every leaf in the btree is read and defragged. 1312 */ 1313 int btrfs_defrag_root(struct btrfs_root *root) 1314 { 1315 struct btrfs_fs_info *info = root->fs_info; 1316 struct btrfs_trans_handle *trans; 1317 int ret; 1318 1319 if (test_and_set_bit(BTRFS_ROOT_DEFRAG_RUNNING, &root->state)) 1320 return 0; 1321 1322 while (1) { 1323 trans = btrfs_start_transaction(root, 0); 1324 if (IS_ERR(trans)) 1325 return PTR_ERR(trans); 1326 1327 ret = btrfs_defrag_leaves(trans, root); 1328 1329 btrfs_end_transaction(trans); 1330 btrfs_btree_balance_dirty(info); 1331 cond_resched(); 1332 1333 if (btrfs_fs_closing(info) || ret != -EAGAIN) 1334 break; 1335 1336 if (btrfs_defrag_cancelled(info)) { 1337 btrfs_debug(info, "defrag_root cancelled"); 1338 ret = -EAGAIN; 1339 break; 1340 } 1341 } 1342 clear_bit(BTRFS_ROOT_DEFRAG_RUNNING, &root->state); 1343 return ret; 1344 } 1345 1346 /* 1347 * Do all special snapshot related qgroup dirty hack. 1348 * 1349 * Will do all needed qgroup inherit and dirty hack like switch commit 1350 * roots inside one transaction and write all btree into disk, to make 1351 * qgroup works. 1352 */ 1353 static int qgroup_account_snapshot(struct btrfs_trans_handle *trans, 1354 struct btrfs_root *src, 1355 struct btrfs_root *parent, 1356 struct btrfs_qgroup_inherit *inherit, 1357 u64 dst_objectid) 1358 { 1359 struct btrfs_fs_info *fs_info = src->fs_info; 1360 int ret; 1361 1362 /* 1363 * Save some performance in the case that qgroups are not 1364 * enabled. If this check races with the ioctl, rescan will 1365 * kick in anyway. 1366 */ 1367 if (!test_bit(BTRFS_FS_QUOTA_ENABLED, &fs_info->flags)) 1368 return 0; 1369 1370 /* 1371 * We are going to commit transaction, see btrfs_commit_transaction() 1372 * comment for reason locking tree_log_mutex 1373 */ 1374 mutex_lock(&fs_info->tree_log_mutex); 1375 1376 ret = commit_fs_roots(trans, fs_info); 1377 if (ret) 1378 goto out; 1379 ret = btrfs_qgroup_prepare_account_extents(trans, fs_info); 1380 if (ret < 0) 1381 goto out; 1382 ret = btrfs_qgroup_account_extents(trans, fs_info); 1383 if (ret < 0) 1384 goto out; 1385 1386 /* Now qgroup are all updated, we can inherit it to new qgroups */ 1387 ret = btrfs_qgroup_inherit(trans, fs_info, 1388 src->root_key.objectid, dst_objectid, 1389 inherit); 1390 if (ret < 0) 1391 goto out; 1392 1393 /* 1394 * Now we do a simplified commit transaction, which will: 1395 * 1) commit all subvolume and extent tree 1396 * To ensure all subvolume and extent tree have a valid 1397 * commit_root to accounting later insert_dir_item() 1398 * 2) write all btree blocks onto disk 1399 * This is to make sure later btree modification will be cowed 1400 * Or commit_root can be populated and cause wrong qgroup numbers 1401 * In this simplified commit, we don't really care about other trees 1402 * like chunk and root tree, as they won't affect qgroup. 1403 * And we don't write super to avoid half committed status. 1404 */ 1405 ret = commit_cowonly_roots(trans, fs_info); 1406 if (ret) 1407 goto out; 1408 switch_commit_roots(trans->transaction, fs_info); 1409 ret = btrfs_write_and_wait_transaction(trans, fs_info); 1410 if (ret) 1411 btrfs_handle_fs_error(fs_info, ret, 1412 "Error while writing out transaction for qgroup"); 1413 1414 out: 1415 mutex_unlock(&fs_info->tree_log_mutex); 1416 1417 /* 1418 * Force parent root to be updated, as we recorded it before so its 1419 * last_trans == cur_transid. 1420 * Or it won't be committed again onto disk after later 1421 * insert_dir_item() 1422 */ 1423 if (!ret) 1424 record_root_in_trans(trans, parent, 1); 1425 return ret; 1426 } 1427 1428 /* 1429 * new snapshots need to be created at a very specific time in the 1430 * transaction commit. This does the actual creation. 1431 * 1432 * Note: 1433 * If the error which may affect the commitment of the current transaction 1434 * happens, we should return the error number. If the error which just affect 1435 * the creation of the pending snapshots, just return 0. 1436 */ 1437 static noinline int create_pending_snapshot(struct btrfs_trans_handle *trans, 1438 struct btrfs_fs_info *fs_info, 1439 struct btrfs_pending_snapshot *pending) 1440 { 1441 struct btrfs_key key; 1442 struct btrfs_root_item *new_root_item; 1443 struct btrfs_root *tree_root = fs_info->tree_root; 1444 struct btrfs_root *root = pending->root; 1445 struct btrfs_root *parent_root; 1446 struct btrfs_block_rsv *rsv; 1447 struct inode *parent_inode; 1448 struct btrfs_path *path; 1449 struct btrfs_dir_item *dir_item; 1450 struct dentry *dentry; 1451 struct extent_buffer *tmp; 1452 struct extent_buffer *old; 1453 struct timespec cur_time; 1454 int ret = 0; 1455 u64 to_reserve = 0; 1456 u64 index = 0; 1457 u64 objectid; 1458 u64 root_flags; 1459 uuid_le new_uuid; 1460 1461 ASSERT(pending->path); 1462 path = pending->path; 1463 1464 ASSERT(pending->root_item); 1465 new_root_item = pending->root_item; 1466 1467 pending->error = btrfs_find_free_objectid(tree_root, &objectid); 1468 if (pending->error) 1469 goto no_free_objectid; 1470 1471 /* 1472 * Make qgroup to skip current new snapshot's qgroupid, as it is 1473 * accounted by later btrfs_qgroup_inherit(). 1474 */ 1475 btrfs_set_skip_qgroup(trans, objectid); 1476 1477 btrfs_reloc_pre_snapshot(pending, &to_reserve); 1478 1479 if (to_reserve > 0) { 1480 pending->error = btrfs_block_rsv_add(root, 1481 &pending->block_rsv, 1482 to_reserve, 1483 BTRFS_RESERVE_NO_FLUSH); 1484 if (pending->error) 1485 goto clear_skip_qgroup; 1486 } 1487 1488 key.objectid = objectid; 1489 key.offset = (u64)-1; 1490 key.type = BTRFS_ROOT_ITEM_KEY; 1491 1492 rsv = trans->block_rsv; 1493 trans->block_rsv = &pending->block_rsv; 1494 trans->bytes_reserved = trans->block_rsv->reserved; 1495 trace_btrfs_space_reservation(fs_info, "transaction", 1496 trans->transid, 1497 trans->bytes_reserved, 1); 1498 dentry = pending->dentry; 1499 parent_inode = pending->dir; 1500 parent_root = BTRFS_I(parent_inode)->root; 1501 record_root_in_trans(trans, parent_root, 0); 1502 1503 cur_time = current_time(parent_inode); 1504 1505 /* 1506 * insert the directory item 1507 */ 1508 ret = btrfs_set_inode_index(BTRFS_I(parent_inode), &index); 1509 BUG_ON(ret); /* -ENOMEM */ 1510 1511 /* check if there is a file/dir which has the same name. */ 1512 dir_item = btrfs_lookup_dir_item(NULL, parent_root, path, 1513 btrfs_ino(BTRFS_I(parent_inode)), 1514 dentry->d_name.name, 1515 dentry->d_name.len, 0); 1516 if (dir_item != NULL && !IS_ERR(dir_item)) { 1517 pending->error = -EEXIST; 1518 goto dir_item_existed; 1519 } else if (IS_ERR(dir_item)) { 1520 ret = PTR_ERR(dir_item); 1521 btrfs_abort_transaction(trans, ret); 1522 goto fail; 1523 } 1524 btrfs_release_path(path); 1525 1526 /* 1527 * pull in the delayed directory update 1528 * and the delayed inode item 1529 * otherwise we corrupt the FS during 1530 * snapshot 1531 */ 1532 ret = btrfs_run_delayed_items(trans, fs_info); 1533 if (ret) { /* Transaction aborted */ 1534 btrfs_abort_transaction(trans, ret); 1535 goto fail; 1536 } 1537 1538 record_root_in_trans(trans, root, 0); 1539 btrfs_set_root_last_snapshot(&root->root_item, trans->transid); 1540 memcpy(new_root_item, &root->root_item, sizeof(*new_root_item)); 1541 btrfs_check_and_init_root_item(new_root_item); 1542 1543 root_flags = btrfs_root_flags(new_root_item); 1544 if (pending->readonly) 1545 root_flags |= BTRFS_ROOT_SUBVOL_RDONLY; 1546 else 1547 root_flags &= ~BTRFS_ROOT_SUBVOL_RDONLY; 1548 btrfs_set_root_flags(new_root_item, root_flags); 1549 1550 btrfs_set_root_generation_v2(new_root_item, 1551 trans->transid); 1552 uuid_le_gen(&new_uuid); 1553 memcpy(new_root_item->uuid, new_uuid.b, BTRFS_UUID_SIZE); 1554 memcpy(new_root_item->parent_uuid, root->root_item.uuid, 1555 BTRFS_UUID_SIZE); 1556 if (!(root_flags & BTRFS_ROOT_SUBVOL_RDONLY)) { 1557 memset(new_root_item->received_uuid, 0, 1558 sizeof(new_root_item->received_uuid)); 1559 memset(&new_root_item->stime, 0, sizeof(new_root_item->stime)); 1560 memset(&new_root_item->rtime, 0, sizeof(new_root_item->rtime)); 1561 btrfs_set_root_stransid(new_root_item, 0); 1562 btrfs_set_root_rtransid(new_root_item, 0); 1563 } 1564 btrfs_set_stack_timespec_sec(&new_root_item->otime, cur_time.tv_sec); 1565 btrfs_set_stack_timespec_nsec(&new_root_item->otime, cur_time.tv_nsec); 1566 btrfs_set_root_otransid(new_root_item, trans->transid); 1567 1568 old = btrfs_lock_root_node(root); 1569 ret = btrfs_cow_block(trans, root, old, NULL, 0, &old); 1570 if (ret) { 1571 btrfs_tree_unlock(old); 1572 free_extent_buffer(old); 1573 btrfs_abort_transaction(trans, ret); 1574 goto fail; 1575 } 1576 1577 btrfs_set_lock_blocking(old); 1578 1579 ret = btrfs_copy_root(trans, root, old, &tmp, objectid); 1580 /* clean up in any case */ 1581 btrfs_tree_unlock(old); 1582 free_extent_buffer(old); 1583 if (ret) { 1584 btrfs_abort_transaction(trans, ret); 1585 goto fail; 1586 } 1587 /* see comments in should_cow_block() */ 1588 set_bit(BTRFS_ROOT_FORCE_COW, &root->state); 1589 smp_wmb(); 1590 1591 btrfs_set_root_node(new_root_item, tmp); 1592 /* record when the snapshot was created in key.offset */ 1593 key.offset = trans->transid; 1594 ret = btrfs_insert_root(trans, tree_root, &key, new_root_item); 1595 btrfs_tree_unlock(tmp); 1596 free_extent_buffer(tmp); 1597 if (ret) { 1598 btrfs_abort_transaction(trans, ret); 1599 goto fail; 1600 } 1601 1602 /* 1603 * insert root back/forward references 1604 */ 1605 ret = btrfs_add_root_ref(trans, fs_info, objectid, 1606 parent_root->root_key.objectid, 1607 btrfs_ino(BTRFS_I(parent_inode)), index, 1608 dentry->d_name.name, dentry->d_name.len); 1609 if (ret) { 1610 btrfs_abort_transaction(trans, ret); 1611 goto fail; 1612 } 1613 1614 key.offset = (u64)-1; 1615 pending->snap = btrfs_read_fs_root_no_name(fs_info, &key); 1616 if (IS_ERR(pending->snap)) { 1617 ret = PTR_ERR(pending->snap); 1618 btrfs_abort_transaction(trans, ret); 1619 goto fail; 1620 } 1621 1622 ret = btrfs_reloc_post_snapshot(trans, pending); 1623 if (ret) { 1624 btrfs_abort_transaction(trans, ret); 1625 goto fail; 1626 } 1627 1628 ret = btrfs_run_delayed_refs(trans, fs_info, (unsigned long)-1); 1629 if (ret) { 1630 btrfs_abort_transaction(trans, ret); 1631 goto fail; 1632 } 1633 1634 /* 1635 * Do special qgroup accounting for snapshot, as we do some qgroup 1636 * snapshot hack to do fast snapshot. 1637 * To co-operate with that hack, we do hack again. 1638 * Or snapshot will be greatly slowed down by a subtree qgroup rescan 1639 */ 1640 ret = qgroup_account_snapshot(trans, root, parent_root, 1641 pending->inherit, objectid); 1642 if (ret < 0) 1643 goto fail; 1644 1645 ret = btrfs_insert_dir_item(trans, parent_root, 1646 dentry->d_name.name, dentry->d_name.len, 1647 BTRFS_I(parent_inode), &key, 1648 BTRFS_FT_DIR, index); 1649 /* We have check then name at the beginning, so it is impossible. */ 1650 BUG_ON(ret == -EEXIST || ret == -EOVERFLOW); 1651 if (ret) { 1652 btrfs_abort_transaction(trans, ret); 1653 goto fail; 1654 } 1655 1656 btrfs_i_size_write(BTRFS_I(parent_inode), parent_inode->i_size + 1657 dentry->d_name.len * 2); 1658 parent_inode->i_mtime = parent_inode->i_ctime = 1659 current_time(parent_inode); 1660 ret = btrfs_update_inode_fallback(trans, parent_root, parent_inode); 1661 if (ret) { 1662 btrfs_abort_transaction(trans, ret); 1663 goto fail; 1664 } 1665 ret = btrfs_uuid_tree_add(trans, fs_info, new_uuid.b, 1666 BTRFS_UUID_KEY_SUBVOL, objectid); 1667 if (ret) { 1668 btrfs_abort_transaction(trans, ret); 1669 goto fail; 1670 } 1671 if (!btrfs_is_empty_uuid(new_root_item->received_uuid)) { 1672 ret = btrfs_uuid_tree_add(trans, fs_info, 1673 new_root_item->received_uuid, 1674 BTRFS_UUID_KEY_RECEIVED_SUBVOL, 1675 objectid); 1676 if (ret && ret != -EEXIST) { 1677 btrfs_abort_transaction(trans, ret); 1678 goto fail; 1679 } 1680 } 1681 1682 ret = btrfs_run_delayed_refs(trans, fs_info, (unsigned long)-1); 1683 if (ret) { 1684 btrfs_abort_transaction(trans, ret); 1685 goto fail; 1686 } 1687 1688 fail: 1689 pending->error = ret; 1690 dir_item_existed: 1691 trans->block_rsv = rsv; 1692 trans->bytes_reserved = 0; 1693 clear_skip_qgroup: 1694 btrfs_clear_skip_qgroup(trans); 1695 no_free_objectid: 1696 kfree(new_root_item); 1697 pending->root_item = NULL; 1698 btrfs_free_path(path); 1699 pending->path = NULL; 1700 1701 return ret; 1702 } 1703 1704 /* 1705 * create all the snapshots we've scheduled for creation 1706 */ 1707 static noinline int create_pending_snapshots(struct btrfs_trans_handle *trans, 1708 struct btrfs_fs_info *fs_info) 1709 { 1710 struct btrfs_pending_snapshot *pending, *next; 1711 struct list_head *head = &trans->transaction->pending_snapshots; 1712 int ret = 0; 1713 1714 list_for_each_entry_safe(pending, next, head, list) { 1715 list_del(&pending->list); 1716 ret = create_pending_snapshot(trans, fs_info, pending); 1717 if (ret) 1718 break; 1719 } 1720 return ret; 1721 } 1722 1723 static void update_super_roots(struct btrfs_fs_info *fs_info) 1724 { 1725 struct btrfs_root_item *root_item; 1726 struct btrfs_super_block *super; 1727 1728 super = fs_info->super_copy; 1729 1730 root_item = &fs_info->chunk_root->root_item; 1731 super->chunk_root = root_item->bytenr; 1732 super->chunk_root_generation = root_item->generation; 1733 super->chunk_root_level = root_item->level; 1734 1735 root_item = &fs_info->tree_root->root_item; 1736 super->root = root_item->bytenr; 1737 super->generation = root_item->generation; 1738 super->root_level = root_item->level; 1739 if (btrfs_test_opt(fs_info, SPACE_CACHE)) 1740 super->cache_generation = root_item->generation; 1741 if (test_bit(BTRFS_FS_UPDATE_UUID_TREE_GEN, &fs_info->flags)) 1742 super->uuid_tree_generation = root_item->generation; 1743 } 1744 1745 int btrfs_transaction_in_commit(struct btrfs_fs_info *info) 1746 { 1747 struct btrfs_transaction *trans; 1748 int ret = 0; 1749 1750 spin_lock(&info->trans_lock); 1751 trans = info->running_transaction; 1752 if (trans) 1753 ret = (trans->state >= TRANS_STATE_COMMIT_START); 1754 spin_unlock(&info->trans_lock); 1755 return ret; 1756 } 1757 1758 int btrfs_transaction_blocked(struct btrfs_fs_info *info) 1759 { 1760 struct btrfs_transaction *trans; 1761 int ret = 0; 1762 1763 spin_lock(&info->trans_lock); 1764 trans = info->running_transaction; 1765 if (trans) 1766 ret = is_transaction_blocked(trans); 1767 spin_unlock(&info->trans_lock); 1768 return ret; 1769 } 1770 1771 /* 1772 * wait for the current transaction commit to start and block subsequent 1773 * transaction joins 1774 */ 1775 static void wait_current_trans_commit_start(struct btrfs_fs_info *fs_info, 1776 struct btrfs_transaction *trans) 1777 { 1778 wait_event(fs_info->transaction_blocked_wait, 1779 trans->state >= TRANS_STATE_COMMIT_START || trans->aborted); 1780 } 1781 1782 /* 1783 * wait for the current transaction to start and then become unblocked. 1784 * caller holds ref. 1785 */ 1786 static void wait_current_trans_commit_start_and_unblock( 1787 struct btrfs_fs_info *fs_info, 1788 struct btrfs_transaction *trans) 1789 { 1790 wait_event(fs_info->transaction_wait, 1791 trans->state >= TRANS_STATE_UNBLOCKED || trans->aborted); 1792 } 1793 1794 /* 1795 * commit transactions asynchronously. once btrfs_commit_transaction_async 1796 * returns, any subsequent transaction will not be allowed to join. 1797 */ 1798 struct btrfs_async_commit { 1799 struct btrfs_trans_handle *newtrans; 1800 struct work_struct work; 1801 }; 1802 1803 static void do_async_commit(struct work_struct *work) 1804 { 1805 struct btrfs_async_commit *ac = 1806 container_of(work, struct btrfs_async_commit, work); 1807 1808 /* 1809 * We've got freeze protection passed with the transaction. 1810 * Tell lockdep about it. 1811 */ 1812 if (ac->newtrans->type & __TRANS_FREEZABLE) 1813 __sb_writers_acquired(ac->newtrans->fs_info->sb, SB_FREEZE_FS); 1814 1815 current->journal_info = ac->newtrans; 1816 1817 btrfs_commit_transaction(ac->newtrans); 1818 kfree(ac); 1819 } 1820 1821 int btrfs_commit_transaction_async(struct btrfs_trans_handle *trans, 1822 int wait_for_unblock) 1823 { 1824 struct btrfs_fs_info *fs_info = trans->fs_info; 1825 struct btrfs_async_commit *ac; 1826 struct btrfs_transaction *cur_trans; 1827 1828 ac = kmalloc(sizeof(*ac), GFP_NOFS); 1829 if (!ac) 1830 return -ENOMEM; 1831 1832 INIT_WORK(&ac->work, do_async_commit); 1833 ac->newtrans = btrfs_join_transaction(trans->root); 1834 if (IS_ERR(ac->newtrans)) { 1835 int err = PTR_ERR(ac->newtrans); 1836 kfree(ac); 1837 return err; 1838 } 1839 1840 /* take transaction reference */ 1841 cur_trans = trans->transaction; 1842 atomic_inc(&cur_trans->use_count); 1843 1844 btrfs_end_transaction(trans); 1845 1846 /* 1847 * Tell lockdep we've released the freeze rwsem, since the 1848 * async commit thread will be the one to unlock it. 1849 */ 1850 if (ac->newtrans->type & __TRANS_FREEZABLE) 1851 __sb_writers_release(fs_info->sb, SB_FREEZE_FS); 1852 1853 schedule_work(&ac->work); 1854 1855 /* wait for transaction to start and unblock */ 1856 if (wait_for_unblock) 1857 wait_current_trans_commit_start_and_unblock(fs_info, cur_trans); 1858 else 1859 wait_current_trans_commit_start(fs_info, cur_trans); 1860 1861 if (current->journal_info == trans) 1862 current->journal_info = NULL; 1863 1864 btrfs_put_transaction(cur_trans); 1865 return 0; 1866 } 1867 1868 1869 static void cleanup_transaction(struct btrfs_trans_handle *trans, 1870 struct btrfs_root *root, int err) 1871 { 1872 struct btrfs_fs_info *fs_info = root->fs_info; 1873 struct btrfs_transaction *cur_trans = trans->transaction; 1874 DEFINE_WAIT(wait); 1875 1876 WARN_ON(trans->use_count > 1); 1877 1878 btrfs_abort_transaction(trans, err); 1879 1880 spin_lock(&fs_info->trans_lock); 1881 1882 /* 1883 * If the transaction is removed from the list, it means this 1884 * transaction has been committed successfully, so it is impossible 1885 * to call the cleanup function. 1886 */ 1887 BUG_ON(list_empty(&cur_trans->list)); 1888 1889 list_del_init(&cur_trans->list); 1890 if (cur_trans == fs_info->running_transaction) { 1891 cur_trans->state = TRANS_STATE_COMMIT_DOING; 1892 spin_unlock(&fs_info->trans_lock); 1893 wait_event(cur_trans->writer_wait, 1894 atomic_read(&cur_trans->num_writers) == 1); 1895 1896 spin_lock(&fs_info->trans_lock); 1897 } 1898 spin_unlock(&fs_info->trans_lock); 1899 1900 btrfs_cleanup_one_transaction(trans->transaction, fs_info); 1901 1902 spin_lock(&fs_info->trans_lock); 1903 if (cur_trans == fs_info->running_transaction) 1904 fs_info->running_transaction = NULL; 1905 spin_unlock(&fs_info->trans_lock); 1906 1907 if (trans->type & __TRANS_FREEZABLE) 1908 sb_end_intwrite(fs_info->sb); 1909 btrfs_put_transaction(cur_trans); 1910 btrfs_put_transaction(cur_trans); 1911 1912 trace_btrfs_transaction_commit(root); 1913 1914 if (current->journal_info == trans) 1915 current->journal_info = NULL; 1916 btrfs_scrub_cancel(fs_info); 1917 1918 kmem_cache_free(btrfs_trans_handle_cachep, trans); 1919 } 1920 1921 static inline int btrfs_start_delalloc_flush(struct btrfs_fs_info *fs_info) 1922 { 1923 if (btrfs_test_opt(fs_info, FLUSHONCOMMIT)) 1924 return btrfs_start_delalloc_roots(fs_info, 1, -1); 1925 return 0; 1926 } 1927 1928 static inline void btrfs_wait_delalloc_flush(struct btrfs_fs_info *fs_info) 1929 { 1930 if (btrfs_test_opt(fs_info, FLUSHONCOMMIT)) 1931 btrfs_wait_ordered_roots(fs_info, -1, 0, (u64)-1); 1932 } 1933 1934 static inline void 1935 btrfs_wait_pending_ordered(struct btrfs_transaction *cur_trans) 1936 { 1937 wait_event(cur_trans->pending_wait, 1938 atomic_read(&cur_trans->pending_ordered) == 0); 1939 } 1940 1941 int btrfs_commit_transaction(struct btrfs_trans_handle *trans) 1942 { 1943 struct btrfs_fs_info *fs_info = trans->fs_info; 1944 struct btrfs_transaction *cur_trans = trans->transaction; 1945 struct btrfs_transaction *prev_trans = NULL; 1946 int ret; 1947 1948 /* Stop the commit early if ->aborted is set */ 1949 if (unlikely(READ_ONCE(cur_trans->aborted))) { 1950 ret = cur_trans->aborted; 1951 btrfs_end_transaction(trans); 1952 return ret; 1953 } 1954 1955 /* make a pass through all the delayed refs we have so far 1956 * any runnings procs may add more while we are here 1957 */ 1958 ret = btrfs_run_delayed_refs(trans, fs_info, 0); 1959 if (ret) { 1960 btrfs_end_transaction(trans); 1961 return ret; 1962 } 1963 1964 btrfs_trans_release_metadata(trans, fs_info); 1965 trans->block_rsv = NULL; 1966 1967 cur_trans = trans->transaction; 1968 1969 /* 1970 * set the flushing flag so procs in this transaction have to 1971 * start sending their work down. 1972 */ 1973 cur_trans->delayed_refs.flushing = 1; 1974 smp_wmb(); 1975 1976 if (!list_empty(&trans->new_bgs)) 1977 btrfs_create_pending_block_groups(trans, fs_info); 1978 1979 ret = btrfs_run_delayed_refs(trans, fs_info, 0); 1980 if (ret) { 1981 btrfs_end_transaction(trans); 1982 return ret; 1983 } 1984 1985 if (!test_bit(BTRFS_TRANS_DIRTY_BG_RUN, &cur_trans->flags)) { 1986 int run_it = 0; 1987 1988 /* this mutex is also taken before trying to set 1989 * block groups readonly. We need to make sure 1990 * that nobody has set a block group readonly 1991 * after a extents from that block group have been 1992 * allocated for cache files. btrfs_set_block_group_ro 1993 * will wait for the transaction to commit if it 1994 * finds BTRFS_TRANS_DIRTY_BG_RUN set. 1995 * 1996 * The BTRFS_TRANS_DIRTY_BG_RUN flag is also used to make sure 1997 * only one process starts all the block group IO. It wouldn't 1998 * hurt to have more than one go through, but there's no 1999 * real advantage to it either. 2000 */ 2001 mutex_lock(&fs_info->ro_block_group_mutex); 2002 if (!test_and_set_bit(BTRFS_TRANS_DIRTY_BG_RUN, 2003 &cur_trans->flags)) 2004 run_it = 1; 2005 mutex_unlock(&fs_info->ro_block_group_mutex); 2006 2007 if (run_it) 2008 ret = btrfs_start_dirty_block_groups(trans, fs_info); 2009 } 2010 if (ret) { 2011 btrfs_end_transaction(trans); 2012 return ret; 2013 } 2014 2015 spin_lock(&fs_info->trans_lock); 2016 if (cur_trans->state >= TRANS_STATE_COMMIT_START) { 2017 spin_unlock(&fs_info->trans_lock); 2018 atomic_inc(&cur_trans->use_count); 2019 ret = btrfs_end_transaction(trans); 2020 2021 wait_for_commit(cur_trans); 2022 2023 if (unlikely(cur_trans->aborted)) 2024 ret = cur_trans->aborted; 2025 2026 btrfs_put_transaction(cur_trans); 2027 2028 return ret; 2029 } 2030 2031 cur_trans->state = TRANS_STATE_COMMIT_START; 2032 wake_up(&fs_info->transaction_blocked_wait); 2033 2034 if (cur_trans->list.prev != &fs_info->trans_list) { 2035 prev_trans = list_entry(cur_trans->list.prev, 2036 struct btrfs_transaction, list); 2037 if (prev_trans->state != TRANS_STATE_COMPLETED) { 2038 atomic_inc(&prev_trans->use_count); 2039 spin_unlock(&fs_info->trans_lock); 2040 2041 wait_for_commit(prev_trans); 2042 ret = prev_trans->aborted; 2043 2044 btrfs_put_transaction(prev_trans); 2045 if (ret) 2046 goto cleanup_transaction; 2047 } else { 2048 spin_unlock(&fs_info->trans_lock); 2049 } 2050 } else { 2051 spin_unlock(&fs_info->trans_lock); 2052 } 2053 2054 extwriter_counter_dec(cur_trans, trans->type); 2055 2056 ret = btrfs_start_delalloc_flush(fs_info); 2057 if (ret) 2058 goto cleanup_transaction; 2059 2060 ret = btrfs_run_delayed_items(trans, fs_info); 2061 if (ret) 2062 goto cleanup_transaction; 2063 2064 wait_event(cur_trans->writer_wait, 2065 extwriter_counter_read(cur_trans) == 0); 2066 2067 /* some pending stuffs might be added after the previous flush. */ 2068 ret = btrfs_run_delayed_items(trans, fs_info); 2069 if (ret) 2070 goto cleanup_transaction; 2071 2072 btrfs_wait_delalloc_flush(fs_info); 2073 2074 btrfs_wait_pending_ordered(cur_trans); 2075 2076 btrfs_scrub_pause(fs_info); 2077 /* 2078 * Ok now we need to make sure to block out any other joins while we 2079 * commit the transaction. We could have started a join before setting 2080 * COMMIT_DOING so make sure to wait for num_writers to == 1 again. 2081 */ 2082 spin_lock(&fs_info->trans_lock); 2083 cur_trans->state = TRANS_STATE_COMMIT_DOING; 2084 spin_unlock(&fs_info->trans_lock); 2085 wait_event(cur_trans->writer_wait, 2086 atomic_read(&cur_trans->num_writers) == 1); 2087 2088 /* ->aborted might be set after the previous check, so check it */ 2089 if (unlikely(READ_ONCE(cur_trans->aborted))) { 2090 ret = cur_trans->aborted; 2091 goto scrub_continue; 2092 } 2093 /* 2094 * the reloc mutex makes sure that we stop 2095 * the balancing code from coming in and moving 2096 * extents around in the middle of the commit 2097 */ 2098 mutex_lock(&fs_info->reloc_mutex); 2099 2100 /* 2101 * We needn't worry about the delayed items because we will 2102 * deal with them in create_pending_snapshot(), which is the 2103 * core function of the snapshot creation. 2104 */ 2105 ret = create_pending_snapshots(trans, fs_info); 2106 if (ret) { 2107 mutex_unlock(&fs_info->reloc_mutex); 2108 goto scrub_continue; 2109 } 2110 2111 /* 2112 * We insert the dir indexes of the snapshots and update the inode 2113 * of the snapshots' parents after the snapshot creation, so there 2114 * are some delayed items which are not dealt with. Now deal with 2115 * them. 2116 * 2117 * We needn't worry that this operation will corrupt the snapshots, 2118 * because all the tree which are snapshoted will be forced to COW 2119 * the nodes and leaves. 2120 */ 2121 ret = btrfs_run_delayed_items(trans, fs_info); 2122 if (ret) { 2123 mutex_unlock(&fs_info->reloc_mutex); 2124 goto scrub_continue; 2125 } 2126 2127 ret = btrfs_run_delayed_refs(trans, fs_info, (unsigned long)-1); 2128 if (ret) { 2129 mutex_unlock(&fs_info->reloc_mutex); 2130 goto scrub_continue; 2131 } 2132 2133 /* Reocrd old roots for later qgroup accounting */ 2134 ret = btrfs_qgroup_prepare_account_extents(trans, fs_info); 2135 if (ret) { 2136 mutex_unlock(&fs_info->reloc_mutex); 2137 goto scrub_continue; 2138 } 2139 2140 /* 2141 * make sure none of the code above managed to slip in a 2142 * delayed item 2143 */ 2144 btrfs_assert_delayed_root_empty(fs_info); 2145 2146 WARN_ON(cur_trans != trans->transaction); 2147 2148 /* btrfs_commit_tree_roots is responsible for getting the 2149 * various roots consistent with each other. Every pointer 2150 * in the tree of tree roots has to point to the most up to date 2151 * root for every subvolume and other tree. So, we have to keep 2152 * the tree logging code from jumping in and changing any 2153 * of the trees. 2154 * 2155 * At this point in the commit, there can't be any tree-log 2156 * writers, but a little lower down we drop the trans mutex 2157 * and let new people in. By holding the tree_log_mutex 2158 * from now until after the super is written, we avoid races 2159 * with the tree-log code. 2160 */ 2161 mutex_lock(&fs_info->tree_log_mutex); 2162 2163 ret = commit_fs_roots(trans, fs_info); 2164 if (ret) { 2165 mutex_unlock(&fs_info->tree_log_mutex); 2166 mutex_unlock(&fs_info->reloc_mutex); 2167 goto scrub_continue; 2168 } 2169 2170 /* 2171 * Since the transaction is done, we can apply the pending changes 2172 * before the next transaction. 2173 */ 2174 btrfs_apply_pending_changes(fs_info); 2175 2176 /* commit_fs_roots gets rid of all the tree log roots, it is now 2177 * safe to free the root of tree log roots 2178 */ 2179 btrfs_free_log_root_tree(trans, fs_info); 2180 2181 /* 2182 * Since fs roots are all committed, we can get a quite accurate 2183 * new_roots. So let's do quota accounting. 2184 */ 2185 ret = btrfs_qgroup_account_extents(trans, fs_info); 2186 if (ret < 0) { 2187 mutex_unlock(&fs_info->tree_log_mutex); 2188 mutex_unlock(&fs_info->reloc_mutex); 2189 goto scrub_continue; 2190 } 2191 2192 ret = commit_cowonly_roots(trans, fs_info); 2193 if (ret) { 2194 mutex_unlock(&fs_info->tree_log_mutex); 2195 mutex_unlock(&fs_info->reloc_mutex); 2196 goto scrub_continue; 2197 } 2198 2199 /* 2200 * The tasks which save the space cache and inode cache may also 2201 * update ->aborted, check it. 2202 */ 2203 if (unlikely(READ_ONCE(cur_trans->aborted))) { 2204 ret = cur_trans->aborted; 2205 mutex_unlock(&fs_info->tree_log_mutex); 2206 mutex_unlock(&fs_info->reloc_mutex); 2207 goto scrub_continue; 2208 } 2209 2210 btrfs_prepare_extent_commit(fs_info); 2211 2212 cur_trans = fs_info->running_transaction; 2213 2214 btrfs_set_root_node(&fs_info->tree_root->root_item, 2215 fs_info->tree_root->node); 2216 list_add_tail(&fs_info->tree_root->dirty_list, 2217 &cur_trans->switch_commits); 2218 2219 btrfs_set_root_node(&fs_info->chunk_root->root_item, 2220 fs_info->chunk_root->node); 2221 list_add_tail(&fs_info->chunk_root->dirty_list, 2222 &cur_trans->switch_commits); 2223 2224 switch_commit_roots(cur_trans, fs_info); 2225 2226 assert_qgroups_uptodate(trans); 2227 ASSERT(list_empty(&cur_trans->dirty_bgs)); 2228 ASSERT(list_empty(&cur_trans->io_bgs)); 2229 update_super_roots(fs_info); 2230 2231 btrfs_set_super_log_root(fs_info->super_copy, 0); 2232 btrfs_set_super_log_root_level(fs_info->super_copy, 0); 2233 memcpy(fs_info->super_for_commit, fs_info->super_copy, 2234 sizeof(*fs_info->super_copy)); 2235 2236 btrfs_update_commit_device_size(fs_info); 2237 btrfs_update_commit_device_bytes_used(fs_info, cur_trans); 2238 2239 clear_bit(BTRFS_FS_LOG1_ERR, &fs_info->flags); 2240 clear_bit(BTRFS_FS_LOG2_ERR, &fs_info->flags); 2241 2242 btrfs_trans_release_chunk_metadata(trans); 2243 2244 spin_lock(&fs_info->trans_lock); 2245 cur_trans->state = TRANS_STATE_UNBLOCKED; 2246 fs_info->running_transaction = NULL; 2247 spin_unlock(&fs_info->trans_lock); 2248 mutex_unlock(&fs_info->reloc_mutex); 2249 2250 wake_up(&fs_info->transaction_wait); 2251 2252 ret = btrfs_write_and_wait_transaction(trans, fs_info); 2253 if (ret) { 2254 btrfs_handle_fs_error(fs_info, ret, 2255 "Error while writing out transaction"); 2256 mutex_unlock(&fs_info->tree_log_mutex); 2257 goto scrub_continue; 2258 } 2259 2260 ret = write_all_supers(fs_info, 0); 2261 if (ret) { 2262 mutex_unlock(&fs_info->tree_log_mutex); 2263 goto scrub_continue; 2264 } 2265 2266 /* 2267 * the super is written, we can safely allow the tree-loggers 2268 * to go about their business 2269 */ 2270 mutex_unlock(&fs_info->tree_log_mutex); 2271 2272 btrfs_finish_extent_commit(trans, fs_info); 2273 2274 if (test_bit(BTRFS_TRANS_HAVE_FREE_BGS, &cur_trans->flags)) 2275 btrfs_clear_space_info_full(fs_info); 2276 2277 fs_info->last_trans_committed = cur_trans->transid; 2278 /* 2279 * We needn't acquire the lock here because there is no other task 2280 * which can change it. 2281 */ 2282 cur_trans->state = TRANS_STATE_COMPLETED; 2283 wake_up(&cur_trans->commit_wait); 2284 2285 spin_lock(&fs_info->trans_lock); 2286 list_del_init(&cur_trans->list); 2287 spin_unlock(&fs_info->trans_lock); 2288 2289 btrfs_put_transaction(cur_trans); 2290 btrfs_put_transaction(cur_trans); 2291 2292 if (trans->type & __TRANS_FREEZABLE) 2293 sb_end_intwrite(fs_info->sb); 2294 2295 trace_btrfs_transaction_commit(trans->root); 2296 2297 btrfs_scrub_continue(fs_info); 2298 2299 if (current->journal_info == trans) 2300 current->journal_info = NULL; 2301 2302 kmem_cache_free(btrfs_trans_handle_cachep, trans); 2303 2304 /* 2305 * If fs has been frozen, we can not handle delayed iputs, otherwise 2306 * it'll result in deadlock about SB_FREEZE_FS. 2307 */ 2308 if (current != fs_info->transaction_kthread && 2309 current != fs_info->cleaner_kthread && !fs_info->fs_frozen) 2310 btrfs_run_delayed_iputs(fs_info); 2311 2312 return ret; 2313 2314 scrub_continue: 2315 btrfs_scrub_continue(fs_info); 2316 cleanup_transaction: 2317 btrfs_trans_release_metadata(trans, fs_info); 2318 btrfs_trans_release_chunk_metadata(trans); 2319 trans->block_rsv = NULL; 2320 btrfs_warn(fs_info, "Skipping commit of aborted transaction."); 2321 if (current->journal_info == trans) 2322 current->journal_info = NULL; 2323 cleanup_transaction(trans, trans->root, ret); 2324 2325 return ret; 2326 } 2327 2328 /* 2329 * return < 0 if error 2330 * 0 if there are no more dead_roots at the time of call 2331 * 1 there are more to be processed, call me again 2332 * 2333 * The return value indicates there are certainly more snapshots to delete, but 2334 * if there comes a new one during processing, it may return 0. We don't mind, 2335 * because btrfs_commit_super will poke cleaner thread and it will process it a 2336 * few seconds later. 2337 */ 2338 int btrfs_clean_one_deleted_snapshot(struct btrfs_root *root) 2339 { 2340 int ret; 2341 struct btrfs_fs_info *fs_info = root->fs_info; 2342 2343 spin_lock(&fs_info->trans_lock); 2344 if (list_empty(&fs_info->dead_roots)) { 2345 spin_unlock(&fs_info->trans_lock); 2346 return 0; 2347 } 2348 root = list_first_entry(&fs_info->dead_roots, 2349 struct btrfs_root, root_list); 2350 list_del_init(&root->root_list); 2351 spin_unlock(&fs_info->trans_lock); 2352 2353 btrfs_debug(fs_info, "cleaner removing %llu", root->objectid); 2354 2355 btrfs_kill_all_delayed_nodes(root); 2356 2357 if (btrfs_header_backref_rev(root->node) < 2358 BTRFS_MIXED_BACKREF_REV) 2359 ret = btrfs_drop_snapshot(root, NULL, 0, 0); 2360 else 2361 ret = btrfs_drop_snapshot(root, NULL, 1, 0); 2362 2363 return (ret < 0) ? 0 : 1; 2364 } 2365 2366 void btrfs_apply_pending_changes(struct btrfs_fs_info *fs_info) 2367 { 2368 unsigned long prev; 2369 unsigned long bit; 2370 2371 prev = xchg(&fs_info->pending_changes, 0); 2372 if (!prev) 2373 return; 2374 2375 bit = 1 << BTRFS_PENDING_SET_INODE_MAP_CACHE; 2376 if (prev & bit) 2377 btrfs_set_opt(fs_info->mount_opt, INODE_MAP_CACHE); 2378 prev &= ~bit; 2379 2380 bit = 1 << BTRFS_PENDING_CLEAR_INODE_MAP_CACHE; 2381 if (prev & bit) 2382 btrfs_clear_opt(fs_info->mount_opt, INODE_MAP_CACHE); 2383 prev &= ~bit; 2384 2385 bit = 1 << BTRFS_PENDING_COMMIT; 2386 if (prev & bit) 2387 btrfs_debug(fs_info, "pending commit done"); 2388 prev &= ~bit; 2389 2390 if (prev) 2391 btrfs_warn(fs_info, 2392 "unknown pending changes left 0x%lx, ignoring", prev); 2393 } 2394