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(refcount_read(&transaction->use_count) == 0); 64 if (refcount_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 refcount_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 refcount_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 refcount_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->new_bgs); 576 577 smp_mb(); 578 if (cur_trans->state >= TRANS_STATE_BLOCKED && 579 may_wait_transaction(fs_info, type)) { 580 current->journal_info = h; 581 btrfs_commit_transaction(h); 582 goto again; 583 } 584 585 if (num_bytes) { 586 trace_btrfs_space_reservation(fs_info, "transaction", 587 h->transid, num_bytes, 1); 588 h->block_rsv = &fs_info->trans_block_rsv; 589 h->bytes_reserved = num_bytes; 590 h->reloc_reserved = reloc_reserved; 591 } 592 593 got_it: 594 btrfs_record_root_in_trans(h, root); 595 596 if (!current->journal_info && type != TRANS_USERSPACE) 597 current->journal_info = h; 598 return h; 599 600 join_fail: 601 if (type & __TRANS_FREEZABLE) 602 sb_end_intwrite(fs_info->sb); 603 kmem_cache_free(btrfs_trans_handle_cachep, h); 604 alloc_fail: 605 if (num_bytes) 606 btrfs_block_rsv_release(fs_info, &fs_info->trans_block_rsv, 607 num_bytes); 608 reserve_fail: 609 btrfs_qgroup_free_meta(root, qgroup_reserved); 610 return ERR_PTR(ret); 611 } 612 613 struct btrfs_trans_handle *btrfs_start_transaction(struct btrfs_root *root, 614 unsigned int num_items) 615 { 616 return start_transaction(root, num_items, TRANS_START, 617 BTRFS_RESERVE_FLUSH_ALL, true); 618 } 619 620 struct btrfs_trans_handle *btrfs_start_transaction_fallback_global_rsv( 621 struct btrfs_root *root, 622 unsigned int num_items, 623 int min_factor) 624 { 625 struct btrfs_fs_info *fs_info = root->fs_info; 626 struct btrfs_trans_handle *trans; 627 u64 num_bytes; 628 int ret; 629 630 /* 631 * We have two callers: unlink and block group removal. The 632 * former should succeed even if we will temporarily exceed 633 * quota and the latter operates on the extent root so 634 * qgroup enforcement is ignored anyway. 635 */ 636 trans = start_transaction(root, num_items, TRANS_START, 637 BTRFS_RESERVE_FLUSH_ALL, false); 638 if (!IS_ERR(trans) || PTR_ERR(trans) != -ENOSPC) 639 return trans; 640 641 trans = btrfs_start_transaction(root, 0); 642 if (IS_ERR(trans)) 643 return trans; 644 645 num_bytes = btrfs_calc_trans_metadata_size(fs_info, num_items); 646 ret = btrfs_cond_migrate_bytes(fs_info, &fs_info->trans_block_rsv, 647 num_bytes, min_factor); 648 if (ret) { 649 btrfs_end_transaction(trans); 650 return ERR_PTR(ret); 651 } 652 653 trans->block_rsv = &fs_info->trans_block_rsv; 654 trans->bytes_reserved = num_bytes; 655 trace_btrfs_space_reservation(fs_info, "transaction", 656 trans->transid, num_bytes, 1); 657 658 return trans; 659 } 660 661 struct btrfs_trans_handle *btrfs_start_transaction_lflush( 662 struct btrfs_root *root, 663 unsigned int num_items) 664 { 665 return start_transaction(root, num_items, TRANS_START, 666 BTRFS_RESERVE_FLUSH_LIMIT, true); 667 } 668 669 struct btrfs_trans_handle *btrfs_join_transaction(struct btrfs_root *root) 670 { 671 return start_transaction(root, 0, TRANS_JOIN, BTRFS_RESERVE_NO_FLUSH, 672 true); 673 } 674 675 struct btrfs_trans_handle *btrfs_join_transaction_nolock(struct btrfs_root *root) 676 { 677 return start_transaction(root, 0, TRANS_JOIN_NOLOCK, 678 BTRFS_RESERVE_NO_FLUSH, true); 679 } 680 681 struct btrfs_trans_handle *btrfs_start_ioctl_transaction(struct btrfs_root *root) 682 { 683 return start_transaction(root, 0, TRANS_USERSPACE, 684 BTRFS_RESERVE_NO_FLUSH, true); 685 } 686 687 /* 688 * btrfs_attach_transaction() - catch the running transaction 689 * 690 * It is used when we want to commit the current the transaction, but 691 * don't want to start a new one. 692 * 693 * Note: If this function return -ENOENT, it just means there is no 694 * running transaction. But it is possible that the inactive transaction 695 * is still in the memory, not fully on disk. If you hope there is no 696 * inactive transaction in the fs when -ENOENT is returned, you should 697 * invoke 698 * btrfs_attach_transaction_barrier() 699 */ 700 struct btrfs_trans_handle *btrfs_attach_transaction(struct btrfs_root *root) 701 { 702 return start_transaction(root, 0, TRANS_ATTACH, 703 BTRFS_RESERVE_NO_FLUSH, true); 704 } 705 706 /* 707 * btrfs_attach_transaction_barrier() - catch the running transaction 708 * 709 * It is similar to the above function, the differentia is this one 710 * will wait for all the inactive transactions until they fully 711 * complete. 712 */ 713 struct btrfs_trans_handle * 714 btrfs_attach_transaction_barrier(struct btrfs_root *root) 715 { 716 struct btrfs_trans_handle *trans; 717 718 trans = start_transaction(root, 0, TRANS_ATTACH, 719 BTRFS_RESERVE_NO_FLUSH, true); 720 if (IS_ERR(trans) && PTR_ERR(trans) == -ENOENT) 721 btrfs_wait_for_commit(root->fs_info, 0); 722 723 return trans; 724 } 725 726 /* wait for a transaction commit to be fully complete */ 727 static noinline void wait_for_commit(struct btrfs_transaction *commit) 728 { 729 wait_event(commit->commit_wait, commit->state == TRANS_STATE_COMPLETED); 730 } 731 732 int btrfs_wait_for_commit(struct btrfs_fs_info *fs_info, u64 transid) 733 { 734 struct btrfs_transaction *cur_trans = NULL, *t; 735 int ret = 0; 736 737 if (transid) { 738 if (transid <= fs_info->last_trans_committed) 739 goto out; 740 741 /* find specified transaction */ 742 spin_lock(&fs_info->trans_lock); 743 list_for_each_entry(t, &fs_info->trans_list, list) { 744 if (t->transid == transid) { 745 cur_trans = t; 746 refcount_inc(&cur_trans->use_count); 747 ret = 0; 748 break; 749 } 750 if (t->transid > transid) { 751 ret = 0; 752 break; 753 } 754 } 755 spin_unlock(&fs_info->trans_lock); 756 757 /* 758 * The specified transaction doesn't exist, or we 759 * raced with btrfs_commit_transaction 760 */ 761 if (!cur_trans) { 762 if (transid > fs_info->last_trans_committed) 763 ret = -EINVAL; 764 goto out; 765 } 766 } else { 767 /* find newest transaction that is committing | committed */ 768 spin_lock(&fs_info->trans_lock); 769 list_for_each_entry_reverse(t, &fs_info->trans_list, 770 list) { 771 if (t->state >= TRANS_STATE_COMMIT_START) { 772 if (t->state == TRANS_STATE_COMPLETED) 773 break; 774 cur_trans = t; 775 refcount_inc(&cur_trans->use_count); 776 break; 777 } 778 } 779 spin_unlock(&fs_info->trans_lock); 780 if (!cur_trans) 781 goto out; /* nothing committing|committed */ 782 } 783 784 wait_for_commit(cur_trans); 785 btrfs_put_transaction(cur_trans); 786 out: 787 return ret; 788 } 789 790 void btrfs_throttle(struct btrfs_fs_info *fs_info) 791 { 792 if (!atomic_read(&fs_info->open_ioctl_trans)) 793 wait_current_trans(fs_info); 794 } 795 796 static int should_end_transaction(struct btrfs_trans_handle *trans) 797 { 798 struct btrfs_fs_info *fs_info = trans->fs_info; 799 800 if (fs_info->global_block_rsv.space_info->full && 801 btrfs_check_space_for_delayed_refs(trans, fs_info)) 802 return 1; 803 804 return !!btrfs_block_rsv_check(&fs_info->global_block_rsv, 5); 805 } 806 807 int btrfs_should_end_transaction(struct btrfs_trans_handle *trans) 808 { 809 struct btrfs_transaction *cur_trans = trans->transaction; 810 struct btrfs_fs_info *fs_info = trans->fs_info; 811 int updates; 812 int err; 813 814 smp_mb(); 815 if (cur_trans->state >= TRANS_STATE_BLOCKED || 816 cur_trans->delayed_refs.flushing) 817 return 1; 818 819 updates = trans->delayed_ref_updates; 820 trans->delayed_ref_updates = 0; 821 if (updates) { 822 err = btrfs_run_delayed_refs(trans, fs_info, updates * 2); 823 if (err) /* Error code will also eval true */ 824 return err; 825 } 826 827 return should_end_transaction(trans); 828 } 829 830 static int __btrfs_end_transaction(struct btrfs_trans_handle *trans, 831 int throttle) 832 { 833 struct btrfs_fs_info *info = trans->fs_info; 834 struct btrfs_transaction *cur_trans = trans->transaction; 835 u64 transid = trans->transid; 836 unsigned long cur = trans->delayed_ref_updates; 837 int lock = (trans->type != TRANS_JOIN_NOLOCK); 838 int err = 0; 839 int must_run_delayed_refs = 0; 840 841 if (trans->use_count > 1) { 842 trans->use_count--; 843 trans->block_rsv = trans->orig_rsv; 844 return 0; 845 } 846 847 btrfs_trans_release_metadata(trans, info); 848 trans->block_rsv = NULL; 849 850 if (!list_empty(&trans->new_bgs)) 851 btrfs_create_pending_block_groups(trans, info); 852 853 trans->delayed_ref_updates = 0; 854 if (!trans->sync) { 855 must_run_delayed_refs = 856 btrfs_should_throttle_delayed_refs(trans, info); 857 cur = max_t(unsigned long, cur, 32); 858 859 /* 860 * don't make the caller wait if they are from a NOLOCK 861 * or ATTACH transaction, it will deadlock with commit 862 */ 863 if (must_run_delayed_refs == 1 && 864 (trans->type & (__TRANS_JOIN_NOLOCK | __TRANS_ATTACH))) 865 must_run_delayed_refs = 2; 866 } 867 868 btrfs_trans_release_metadata(trans, info); 869 trans->block_rsv = NULL; 870 871 if (!list_empty(&trans->new_bgs)) 872 btrfs_create_pending_block_groups(trans, info); 873 874 btrfs_trans_release_chunk_metadata(trans); 875 876 if (lock && !atomic_read(&info->open_ioctl_trans) && 877 should_end_transaction(trans) && 878 READ_ONCE(cur_trans->state) == TRANS_STATE_RUNNING) { 879 spin_lock(&info->trans_lock); 880 if (cur_trans->state == TRANS_STATE_RUNNING) 881 cur_trans->state = TRANS_STATE_BLOCKED; 882 spin_unlock(&info->trans_lock); 883 } 884 885 if (lock && READ_ONCE(cur_trans->state) == TRANS_STATE_BLOCKED) { 886 if (throttle) 887 return btrfs_commit_transaction(trans); 888 else 889 wake_up_process(info->transaction_kthread); 890 } 891 892 if (trans->type & __TRANS_FREEZABLE) 893 sb_end_intwrite(info->sb); 894 895 WARN_ON(cur_trans != info->running_transaction); 896 WARN_ON(atomic_read(&cur_trans->num_writers) < 1); 897 atomic_dec(&cur_trans->num_writers); 898 extwriter_counter_dec(cur_trans, trans->type); 899 900 /* 901 * Make sure counter is updated before we wake up waiters. 902 */ 903 smp_mb(); 904 if (waitqueue_active(&cur_trans->writer_wait)) 905 wake_up(&cur_trans->writer_wait); 906 btrfs_put_transaction(cur_trans); 907 908 if (current->journal_info == trans) 909 current->journal_info = NULL; 910 911 if (throttle) 912 btrfs_run_delayed_iputs(info); 913 914 if (trans->aborted || 915 test_bit(BTRFS_FS_STATE_ERROR, &info->fs_state)) { 916 wake_up_process(info->transaction_kthread); 917 err = -EIO; 918 } 919 920 kmem_cache_free(btrfs_trans_handle_cachep, trans); 921 if (must_run_delayed_refs) { 922 btrfs_async_run_delayed_refs(info, cur, transid, 923 must_run_delayed_refs == 1); 924 } 925 return err; 926 } 927 928 int btrfs_end_transaction(struct btrfs_trans_handle *trans) 929 { 930 return __btrfs_end_transaction(trans, 0); 931 } 932 933 int btrfs_end_transaction_throttle(struct btrfs_trans_handle *trans) 934 { 935 return __btrfs_end_transaction(trans, 1); 936 } 937 938 /* 939 * when btree blocks are allocated, they have some corresponding bits set for 940 * them in one of two extent_io trees. This is used to make sure all of 941 * those extents are sent to disk but does not wait on them 942 */ 943 int btrfs_write_marked_extents(struct btrfs_fs_info *fs_info, 944 struct extent_io_tree *dirty_pages, int mark) 945 { 946 int err = 0; 947 int werr = 0; 948 struct address_space *mapping = fs_info->btree_inode->i_mapping; 949 struct extent_state *cached_state = NULL; 950 u64 start = 0; 951 u64 end; 952 953 while (!find_first_extent_bit(dirty_pages, start, &start, &end, 954 mark, &cached_state)) { 955 bool wait_writeback = false; 956 957 err = convert_extent_bit(dirty_pages, start, end, 958 EXTENT_NEED_WAIT, 959 mark, &cached_state); 960 /* 961 * convert_extent_bit can return -ENOMEM, which is most of the 962 * time a temporary error. So when it happens, ignore the error 963 * and wait for writeback of this range to finish - because we 964 * failed to set the bit EXTENT_NEED_WAIT for the range, a call 965 * to __btrfs_wait_marked_extents() would not know that 966 * writeback for this range started and therefore wouldn't 967 * wait for it to finish - we don't want to commit a 968 * superblock that points to btree nodes/leafs for which 969 * writeback hasn't finished yet (and without errors). 970 * We cleanup any entries left in the io tree when committing 971 * the transaction (through clear_btree_io_tree()). 972 */ 973 if (err == -ENOMEM) { 974 err = 0; 975 wait_writeback = true; 976 } 977 if (!err) 978 err = filemap_fdatawrite_range(mapping, start, end); 979 if (err) 980 werr = err; 981 else if (wait_writeback) 982 werr = filemap_fdatawait_range(mapping, start, end); 983 free_extent_state(cached_state); 984 cached_state = NULL; 985 cond_resched(); 986 start = end + 1; 987 } 988 return werr; 989 } 990 991 /* 992 * when btree blocks are allocated, they have some corresponding bits set for 993 * them in one of two extent_io trees. This is used to make sure all of 994 * those extents are on disk for transaction or log commit. We wait 995 * on all the pages and clear them from the dirty pages state tree 996 */ 997 static int __btrfs_wait_marked_extents(struct btrfs_fs_info *fs_info, 998 struct extent_io_tree *dirty_pages) 999 { 1000 int err = 0; 1001 int werr = 0; 1002 struct address_space *mapping = fs_info->btree_inode->i_mapping; 1003 struct extent_state *cached_state = NULL; 1004 u64 start = 0; 1005 u64 end; 1006 1007 while (!find_first_extent_bit(dirty_pages, start, &start, &end, 1008 EXTENT_NEED_WAIT, &cached_state)) { 1009 /* 1010 * Ignore -ENOMEM errors returned by clear_extent_bit(). 1011 * When committing the transaction, we'll remove any entries 1012 * left in the io tree. For a log commit, we don't remove them 1013 * after committing the log because the tree can be accessed 1014 * concurrently - we do it only at transaction commit time when 1015 * it's safe to do it (through clear_btree_io_tree()). 1016 */ 1017 err = clear_extent_bit(dirty_pages, start, end, 1018 EXTENT_NEED_WAIT, 1019 0, 0, &cached_state, GFP_NOFS); 1020 if (err == -ENOMEM) 1021 err = 0; 1022 if (!err) 1023 err = filemap_fdatawait_range(mapping, start, end); 1024 if (err) 1025 werr = err; 1026 free_extent_state(cached_state); 1027 cached_state = NULL; 1028 cond_resched(); 1029 start = end + 1; 1030 } 1031 if (err) 1032 werr = err; 1033 return werr; 1034 } 1035 1036 int btrfs_wait_extents(struct btrfs_fs_info *fs_info, 1037 struct extent_io_tree *dirty_pages) 1038 { 1039 bool errors = false; 1040 int err; 1041 1042 err = __btrfs_wait_marked_extents(fs_info, dirty_pages); 1043 if (test_and_clear_bit(BTRFS_FS_BTREE_ERR, &fs_info->flags)) 1044 errors = true; 1045 1046 if (errors && !err) 1047 err = -EIO; 1048 return err; 1049 } 1050 1051 int btrfs_wait_tree_log_extents(struct btrfs_root *log_root, int mark) 1052 { 1053 struct btrfs_fs_info *fs_info = log_root->fs_info; 1054 struct extent_io_tree *dirty_pages = &log_root->dirty_log_pages; 1055 bool errors = false; 1056 int err; 1057 1058 ASSERT(log_root->root_key.objectid == BTRFS_TREE_LOG_OBJECTID); 1059 1060 err = __btrfs_wait_marked_extents(fs_info, dirty_pages); 1061 if ((mark & EXTENT_DIRTY) && 1062 test_and_clear_bit(BTRFS_FS_LOG1_ERR, &fs_info->flags)) 1063 errors = true; 1064 1065 if ((mark & EXTENT_NEW) && 1066 test_and_clear_bit(BTRFS_FS_LOG2_ERR, &fs_info->flags)) 1067 errors = true; 1068 1069 if (errors && !err) 1070 err = -EIO; 1071 return err; 1072 } 1073 1074 /* 1075 * when btree blocks are allocated, they have some corresponding bits set for 1076 * them in one of two extent_io trees. This is used to make sure all of 1077 * those extents are on disk for transaction or log commit 1078 */ 1079 static int btrfs_write_and_wait_marked_extents(struct btrfs_fs_info *fs_info, 1080 struct extent_io_tree *dirty_pages, int mark) 1081 { 1082 int ret; 1083 int ret2; 1084 struct blk_plug plug; 1085 1086 blk_start_plug(&plug); 1087 ret = btrfs_write_marked_extents(fs_info, dirty_pages, mark); 1088 blk_finish_plug(&plug); 1089 ret2 = btrfs_wait_extents(fs_info, dirty_pages); 1090 1091 if (ret) 1092 return ret; 1093 if (ret2) 1094 return ret2; 1095 return 0; 1096 } 1097 1098 static int btrfs_write_and_wait_transaction(struct btrfs_trans_handle *trans, 1099 struct btrfs_fs_info *fs_info) 1100 { 1101 int ret; 1102 1103 ret = btrfs_write_and_wait_marked_extents(fs_info, 1104 &trans->transaction->dirty_pages, 1105 EXTENT_DIRTY); 1106 clear_btree_io_tree(&trans->transaction->dirty_pages); 1107 1108 return ret; 1109 } 1110 1111 /* 1112 * this is used to update the root pointer in the tree of tree roots. 1113 * 1114 * But, in the case of the extent allocation tree, updating the root 1115 * pointer may allocate blocks which may change the root of the extent 1116 * allocation tree. 1117 * 1118 * So, this loops and repeats and makes sure the cowonly root didn't 1119 * change while the root pointer was being updated in the metadata. 1120 */ 1121 static int update_cowonly_root(struct btrfs_trans_handle *trans, 1122 struct btrfs_root *root) 1123 { 1124 int ret; 1125 u64 old_root_bytenr; 1126 u64 old_root_used; 1127 struct btrfs_fs_info *fs_info = root->fs_info; 1128 struct btrfs_root *tree_root = fs_info->tree_root; 1129 1130 old_root_used = btrfs_root_used(&root->root_item); 1131 1132 while (1) { 1133 old_root_bytenr = btrfs_root_bytenr(&root->root_item); 1134 if (old_root_bytenr == root->node->start && 1135 old_root_used == btrfs_root_used(&root->root_item)) 1136 break; 1137 1138 btrfs_set_root_node(&root->root_item, root->node); 1139 ret = btrfs_update_root(trans, tree_root, 1140 &root->root_key, 1141 &root->root_item); 1142 if (ret) 1143 return ret; 1144 1145 old_root_used = btrfs_root_used(&root->root_item); 1146 } 1147 1148 return 0; 1149 } 1150 1151 /* 1152 * update all the cowonly tree roots on disk 1153 * 1154 * The error handling in this function may not be obvious. Any of the 1155 * failures will cause the file system to go offline. We still need 1156 * to clean up the delayed refs. 1157 */ 1158 static noinline int commit_cowonly_roots(struct btrfs_trans_handle *trans, 1159 struct btrfs_fs_info *fs_info) 1160 { 1161 struct list_head *dirty_bgs = &trans->transaction->dirty_bgs; 1162 struct list_head *io_bgs = &trans->transaction->io_bgs; 1163 struct list_head *next; 1164 struct extent_buffer *eb; 1165 int ret; 1166 1167 eb = btrfs_lock_root_node(fs_info->tree_root); 1168 ret = btrfs_cow_block(trans, fs_info->tree_root, eb, NULL, 1169 0, &eb); 1170 btrfs_tree_unlock(eb); 1171 free_extent_buffer(eb); 1172 1173 if (ret) 1174 return ret; 1175 1176 ret = btrfs_run_delayed_refs(trans, fs_info, (unsigned long)-1); 1177 if (ret) 1178 return ret; 1179 1180 ret = btrfs_run_dev_stats(trans, fs_info); 1181 if (ret) 1182 return ret; 1183 ret = btrfs_run_dev_replace(trans, fs_info); 1184 if (ret) 1185 return ret; 1186 ret = btrfs_run_qgroups(trans, fs_info); 1187 if (ret) 1188 return ret; 1189 1190 ret = btrfs_setup_space_cache(trans, fs_info); 1191 if (ret) 1192 return ret; 1193 1194 /* run_qgroups might have added some more refs */ 1195 ret = btrfs_run_delayed_refs(trans, fs_info, (unsigned long)-1); 1196 if (ret) 1197 return ret; 1198 again: 1199 while (!list_empty(&fs_info->dirty_cowonly_roots)) { 1200 struct btrfs_root *root; 1201 next = fs_info->dirty_cowonly_roots.next; 1202 list_del_init(next); 1203 root = list_entry(next, struct btrfs_root, dirty_list); 1204 clear_bit(BTRFS_ROOT_DIRTY, &root->state); 1205 1206 if (root != fs_info->extent_root) 1207 list_add_tail(&root->dirty_list, 1208 &trans->transaction->switch_commits); 1209 ret = update_cowonly_root(trans, root); 1210 if (ret) 1211 return ret; 1212 ret = btrfs_run_delayed_refs(trans, fs_info, (unsigned long)-1); 1213 if (ret) 1214 return ret; 1215 } 1216 1217 while (!list_empty(dirty_bgs) || !list_empty(io_bgs)) { 1218 ret = btrfs_write_dirty_block_groups(trans, fs_info); 1219 if (ret) 1220 return ret; 1221 ret = btrfs_run_delayed_refs(trans, fs_info, (unsigned long)-1); 1222 if (ret) 1223 return ret; 1224 } 1225 1226 if (!list_empty(&fs_info->dirty_cowonly_roots)) 1227 goto again; 1228 1229 list_add_tail(&fs_info->extent_root->dirty_list, 1230 &trans->transaction->switch_commits); 1231 btrfs_after_dev_replace_commit(fs_info); 1232 1233 return 0; 1234 } 1235 1236 /* 1237 * dead roots are old snapshots that need to be deleted. This allocates 1238 * a dirty root struct and adds it into the list of dead roots that need to 1239 * be deleted 1240 */ 1241 void btrfs_add_dead_root(struct btrfs_root *root) 1242 { 1243 struct btrfs_fs_info *fs_info = root->fs_info; 1244 1245 spin_lock(&fs_info->trans_lock); 1246 if (list_empty(&root->root_list)) 1247 list_add_tail(&root->root_list, &fs_info->dead_roots); 1248 spin_unlock(&fs_info->trans_lock); 1249 } 1250 1251 /* 1252 * update all the cowonly tree roots on disk 1253 */ 1254 static noinline int commit_fs_roots(struct btrfs_trans_handle *trans, 1255 struct btrfs_fs_info *fs_info) 1256 { 1257 struct btrfs_root *gang[8]; 1258 int i; 1259 int ret; 1260 int err = 0; 1261 1262 spin_lock(&fs_info->fs_roots_radix_lock); 1263 while (1) { 1264 ret = radix_tree_gang_lookup_tag(&fs_info->fs_roots_radix, 1265 (void **)gang, 0, 1266 ARRAY_SIZE(gang), 1267 BTRFS_ROOT_TRANS_TAG); 1268 if (ret == 0) 1269 break; 1270 for (i = 0; i < ret; i++) { 1271 struct btrfs_root *root = gang[i]; 1272 radix_tree_tag_clear(&fs_info->fs_roots_radix, 1273 (unsigned long)root->root_key.objectid, 1274 BTRFS_ROOT_TRANS_TAG); 1275 spin_unlock(&fs_info->fs_roots_radix_lock); 1276 1277 btrfs_free_log(trans, root); 1278 btrfs_update_reloc_root(trans, root); 1279 btrfs_orphan_commit_root(trans, root); 1280 1281 btrfs_save_ino_cache(root, trans); 1282 1283 /* see comments in should_cow_block() */ 1284 clear_bit(BTRFS_ROOT_FORCE_COW, &root->state); 1285 smp_mb__after_atomic(); 1286 1287 if (root->commit_root != root->node) { 1288 list_add_tail(&root->dirty_list, 1289 &trans->transaction->switch_commits); 1290 btrfs_set_root_node(&root->root_item, 1291 root->node); 1292 } 1293 1294 err = btrfs_update_root(trans, fs_info->tree_root, 1295 &root->root_key, 1296 &root->root_item); 1297 spin_lock(&fs_info->fs_roots_radix_lock); 1298 if (err) 1299 break; 1300 btrfs_qgroup_free_meta_all(root); 1301 } 1302 } 1303 spin_unlock(&fs_info->fs_roots_radix_lock); 1304 return err; 1305 } 1306 1307 /* 1308 * defrag a given btree. 1309 * Every leaf in the btree is read and defragged. 1310 */ 1311 int btrfs_defrag_root(struct btrfs_root *root) 1312 { 1313 struct btrfs_fs_info *info = root->fs_info; 1314 struct btrfs_trans_handle *trans; 1315 int ret; 1316 1317 if (test_and_set_bit(BTRFS_ROOT_DEFRAG_RUNNING, &root->state)) 1318 return 0; 1319 1320 while (1) { 1321 trans = btrfs_start_transaction(root, 0); 1322 if (IS_ERR(trans)) 1323 return PTR_ERR(trans); 1324 1325 ret = btrfs_defrag_leaves(trans, root); 1326 1327 btrfs_end_transaction(trans); 1328 btrfs_btree_balance_dirty(info); 1329 cond_resched(); 1330 1331 if (btrfs_fs_closing(info) || ret != -EAGAIN) 1332 break; 1333 1334 if (btrfs_defrag_cancelled(info)) { 1335 btrfs_debug(info, "defrag_root cancelled"); 1336 ret = -EAGAIN; 1337 break; 1338 } 1339 } 1340 clear_bit(BTRFS_ROOT_DEFRAG_RUNNING, &root->state); 1341 return ret; 1342 } 1343 1344 /* 1345 * Do all special snapshot related qgroup dirty hack. 1346 * 1347 * Will do all needed qgroup inherit and dirty hack like switch commit 1348 * roots inside one transaction and write all btree into disk, to make 1349 * qgroup works. 1350 */ 1351 static int qgroup_account_snapshot(struct btrfs_trans_handle *trans, 1352 struct btrfs_root *src, 1353 struct btrfs_root *parent, 1354 struct btrfs_qgroup_inherit *inherit, 1355 u64 dst_objectid) 1356 { 1357 struct btrfs_fs_info *fs_info = src->fs_info; 1358 int ret; 1359 1360 /* 1361 * Save some performance in the case that qgroups are not 1362 * enabled. If this check races with the ioctl, rescan will 1363 * kick in anyway. 1364 */ 1365 if (!test_bit(BTRFS_FS_QUOTA_ENABLED, &fs_info->flags)) 1366 return 0; 1367 1368 /* 1369 * We are going to commit transaction, see btrfs_commit_transaction() 1370 * comment for reason locking tree_log_mutex 1371 */ 1372 mutex_lock(&fs_info->tree_log_mutex); 1373 1374 ret = commit_fs_roots(trans, fs_info); 1375 if (ret) 1376 goto out; 1377 ret = btrfs_qgroup_prepare_account_extents(trans, fs_info); 1378 if (ret < 0) 1379 goto out; 1380 ret = btrfs_qgroup_account_extents(trans, fs_info); 1381 if (ret < 0) 1382 goto out; 1383 1384 /* Now qgroup are all updated, we can inherit it to new qgroups */ 1385 ret = btrfs_qgroup_inherit(trans, fs_info, 1386 src->root_key.objectid, dst_objectid, 1387 inherit); 1388 if (ret < 0) 1389 goto out; 1390 1391 /* 1392 * Now we do a simplified commit transaction, which will: 1393 * 1) commit all subvolume and extent tree 1394 * To ensure all subvolume and extent tree have a valid 1395 * commit_root to accounting later insert_dir_item() 1396 * 2) write all btree blocks onto disk 1397 * This is to make sure later btree modification will be cowed 1398 * Or commit_root can be populated and cause wrong qgroup numbers 1399 * In this simplified commit, we don't really care about other trees 1400 * like chunk and root tree, as they won't affect qgroup. 1401 * And we don't write super to avoid half committed status. 1402 */ 1403 ret = commit_cowonly_roots(trans, fs_info); 1404 if (ret) 1405 goto out; 1406 switch_commit_roots(trans->transaction, fs_info); 1407 ret = btrfs_write_and_wait_transaction(trans, fs_info); 1408 if (ret) 1409 btrfs_handle_fs_error(fs_info, ret, 1410 "Error while writing out transaction for qgroup"); 1411 1412 out: 1413 mutex_unlock(&fs_info->tree_log_mutex); 1414 1415 /* 1416 * Force parent root to be updated, as we recorded it before so its 1417 * last_trans == cur_transid. 1418 * Or it won't be committed again onto disk after later 1419 * insert_dir_item() 1420 */ 1421 if (!ret) 1422 record_root_in_trans(trans, parent, 1); 1423 return ret; 1424 } 1425 1426 /* 1427 * new snapshots need to be created at a very specific time in the 1428 * transaction commit. This does the actual creation. 1429 * 1430 * Note: 1431 * If the error which may affect the commitment of the current transaction 1432 * happens, we should return the error number. If the error which just affect 1433 * the creation of the pending snapshots, just return 0. 1434 */ 1435 static noinline int create_pending_snapshot(struct btrfs_trans_handle *trans, 1436 struct btrfs_fs_info *fs_info, 1437 struct btrfs_pending_snapshot *pending) 1438 { 1439 struct btrfs_key key; 1440 struct btrfs_root_item *new_root_item; 1441 struct btrfs_root *tree_root = fs_info->tree_root; 1442 struct btrfs_root *root = pending->root; 1443 struct btrfs_root *parent_root; 1444 struct btrfs_block_rsv *rsv; 1445 struct inode *parent_inode; 1446 struct btrfs_path *path; 1447 struct btrfs_dir_item *dir_item; 1448 struct dentry *dentry; 1449 struct extent_buffer *tmp; 1450 struct extent_buffer *old; 1451 struct timespec cur_time; 1452 int ret = 0; 1453 u64 to_reserve = 0; 1454 u64 index = 0; 1455 u64 objectid; 1456 u64 root_flags; 1457 uuid_le new_uuid; 1458 1459 ASSERT(pending->path); 1460 path = pending->path; 1461 1462 ASSERT(pending->root_item); 1463 new_root_item = pending->root_item; 1464 1465 pending->error = btrfs_find_free_objectid(tree_root, &objectid); 1466 if (pending->error) 1467 goto no_free_objectid; 1468 1469 /* 1470 * Make qgroup to skip current new snapshot's qgroupid, as it is 1471 * accounted by later btrfs_qgroup_inherit(). 1472 */ 1473 btrfs_set_skip_qgroup(trans, objectid); 1474 1475 btrfs_reloc_pre_snapshot(pending, &to_reserve); 1476 1477 if (to_reserve > 0) { 1478 pending->error = btrfs_block_rsv_add(root, 1479 &pending->block_rsv, 1480 to_reserve, 1481 BTRFS_RESERVE_NO_FLUSH); 1482 if (pending->error) 1483 goto clear_skip_qgroup; 1484 } 1485 1486 key.objectid = objectid; 1487 key.offset = (u64)-1; 1488 key.type = BTRFS_ROOT_ITEM_KEY; 1489 1490 rsv = trans->block_rsv; 1491 trans->block_rsv = &pending->block_rsv; 1492 trans->bytes_reserved = trans->block_rsv->reserved; 1493 trace_btrfs_space_reservation(fs_info, "transaction", 1494 trans->transid, 1495 trans->bytes_reserved, 1); 1496 dentry = pending->dentry; 1497 parent_inode = pending->dir; 1498 parent_root = BTRFS_I(parent_inode)->root; 1499 record_root_in_trans(trans, parent_root, 0); 1500 1501 cur_time = current_time(parent_inode); 1502 1503 /* 1504 * insert the directory item 1505 */ 1506 ret = btrfs_set_inode_index(BTRFS_I(parent_inode), &index); 1507 BUG_ON(ret); /* -ENOMEM */ 1508 1509 /* check if there is a file/dir which has the same name. */ 1510 dir_item = btrfs_lookup_dir_item(NULL, parent_root, path, 1511 btrfs_ino(BTRFS_I(parent_inode)), 1512 dentry->d_name.name, 1513 dentry->d_name.len, 0); 1514 if (dir_item != NULL && !IS_ERR(dir_item)) { 1515 pending->error = -EEXIST; 1516 goto dir_item_existed; 1517 } else if (IS_ERR(dir_item)) { 1518 ret = PTR_ERR(dir_item); 1519 btrfs_abort_transaction(trans, ret); 1520 goto fail; 1521 } 1522 btrfs_release_path(path); 1523 1524 /* 1525 * pull in the delayed directory update 1526 * and the delayed inode item 1527 * otherwise we corrupt the FS during 1528 * snapshot 1529 */ 1530 ret = btrfs_run_delayed_items(trans, fs_info); 1531 if (ret) { /* Transaction aborted */ 1532 btrfs_abort_transaction(trans, ret); 1533 goto fail; 1534 } 1535 1536 record_root_in_trans(trans, root, 0); 1537 btrfs_set_root_last_snapshot(&root->root_item, trans->transid); 1538 memcpy(new_root_item, &root->root_item, sizeof(*new_root_item)); 1539 btrfs_check_and_init_root_item(new_root_item); 1540 1541 root_flags = btrfs_root_flags(new_root_item); 1542 if (pending->readonly) 1543 root_flags |= BTRFS_ROOT_SUBVOL_RDONLY; 1544 else 1545 root_flags &= ~BTRFS_ROOT_SUBVOL_RDONLY; 1546 btrfs_set_root_flags(new_root_item, root_flags); 1547 1548 btrfs_set_root_generation_v2(new_root_item, 1549 trans->transid); 1550 uuid_le_gen(&new_uuid); 1551 memcpy(new_root_item->uuid, new_uuid.b, BTRFS_UUID_SIZE); 1552 memcpy(new_root_item->parent_uuid, root->root_item.uuid, 1553 BTRFS_UUID_SIZE); 1554 if (!(root_flags & BTRFS_ROOT_SUBVOL_RDONLY)) { 1555 memset(new_root_item->received_uuid, 0, 1556 sizeof(new_root_item->received_uuid)); 1557 memset(&new_root_item->stime, 0, sizeof(new_root_item->stime)); 1558 memset(&new_root_item->rtime, 0, sizeof(new_root_item->rtime)); 1559 btrfs_set_root_stransid(new_root_item, 0); 1560 btrfs_set_root_rtransid(new_root_item, 0); 1561 } 1562 btrfs_set_stack_timespec_sec(&new_root_item->otime, cur_time.tv_sec); 1563 btrfs_set_stack_timespec_nsec(&new_root_item->otime, cur_time.tv_nsec); 1564 btrfs_set_root_otransid(new_root_item, trans->transid); 1565 1566 old = btrfs_lock_root_node(root); 1567 ret = btrfs_cow_block(trans, root, old, NULL, 0, &old); 1568 if (ret) { 1569 btrfs_tree_unlock(old); 1570 free_extent_buffer(old); 1571 btrfs_abort_transaction(trans, ret); 1572 goto fail; 1573 } 1574 1575 btrfs_set_lock_blocking(old); 1576 1577 ret = btrfs_copy_root(trans, root, old, &tmp, objectid); 1578 /* clean up in any case */ 1579 btrfs_tree_unlock(old); 1580 free_extent_buffer(old); 1581 if (ret) { 1582 btrfs_abort_transaction(trans, ret); 1583 goto fail; 1584 } 1585 /* see comments in should_cow_block() */ 1586 set_bit(BTRFS_ROOT_FORCE_COW, &root->state); 1587 smp_wmb(); 1588 1589 btrfs_set_root_node(new_root_item, tmp); 1590 /* record when the snapshot was created in key.offset */ 1591 key.offset = trans->transid; 1592 ret = btrfs_insert_root(trans, tree_root, &key, new_root_item); 1593 btrfs_tree_unlock(tmp); 1594 free_extent_buffer(tmp); 1595 if (ret) { 1596 btrfs_abort_transaction(trans, ret); 1597 goto fail; 1598 } 1599 1600 /* 1601 * insert root back/forward references 1602 */ 1603 ret = btrfs_add_root_ref(trans, fs_info, objectid, 1604 parent_root->root_key.objectid, 1605 btrfs_ino(BTRFS_I(parent_inode)), index, 1606 dentry->d_name.name, dentry->d_name.len); 1607 if (ret) { 1608 btrfs_abort_transaction(trans, ret); 1609 goto fail; 1610 } 1611 1612 key.offset = (u64)-1; 1613 pending->snap = btrfs_read_fs_root_no_name(fs_info, &key); 1614 if (IS_ERR(pending->snap)) { 1615 ret = PTR_ERR(pending->snap); 1616 btrfs_abort_transaction(trans, ret); 1617 goto fail; 1618 } 1619 1620 ret = btrfs_reloc_post_snapshot(trans, pending); 1621 if (ret) { 1622 btrfs_abort_transaction(trans, ret); 1623 goto fail; 1624 } 1625 1626 ret = btrfs_run_delayed_refs(trans, fs_info, (unsigned long)-1); 1627 if (ret) { 1628 btrfs_abort_transaction(trans, ret); 1629 goto fail; 1630 } 1631 1632 /* 1633 * Do special qgroup accounting for snapshot, as we do some qgroup 1634 * snapshot hack to do fast snapshot. 1635 * To co-operate with that hack, we do hack again. 1636 * Or snapshot will be greatly slowed down by a subtree qgroup rescan 1637 */ 1638 ret = qgroup_account_snapshot(trans, root, parent_root, 1639 pending->inherit, objectid); 1640 if (ret < 0) 1641 goto fail; 1642 1643 ret = btrfs_insert_dir_item(trans, parent_root, 1644 dentry->d_name.name, dentry->d_name.len, 1645 BTRFS_I(parent_inode), &key, 1646 BTRFS_FT_DIR, index); 1647 /* We have check then name at the beginning, so it is impossible. */ 1648 BUG_ON(ret == -EEXIST || ret == -EOVERFLOW); 1649 if (ret) { 1650 btrfs_abort_transaction(trans, ret); 1651 goto fail; 1652 } 1653 1654 btrfs_i_size_write(BTRFS_I(parent_inode), parent_inode->i_size + 1655 dentry->d_name.len * 2); 1656 parent_inode->i_mtime = parent_inode->i_ctime = 1657 current_time(parent_inode); 1658 ret = btrfs_update_inode_fallback(trans, parent_root, parent_inode); 1659 if (ret) { 1660 btrfs_abort_transaction(trans, ret); 1661 goto fail; 1662 } 1663 ret = btrfs_uuid_tree_add(trans, fs_info, new_uuid.b, 1664 BTRFS_UUID_KEY_SUBVOL, objectid); 1665 if (ret) { 1666 btrfs_abort_transaction(trans, ret); 1667 goto fail; 1668 } 1669 if (!btrfs_is_empty_uuid(new_root_item->received_uuid)) { 1670 ret = btrfs_uuid_tree_add(trans, fs_info, 1671 new_root_item->received_uuid, 1672 BTRFS_UUID_KEY_RECEIVED_SUBVOL, 1673 objectid); 1674 if (ret && ret != -EEXIST) { 1675 btrfs_abort_transaction(trans, ret); 1676 goto fail; 1677 } 1678 } 1679 1680 ret = btrfs_run_delayed_refs(trans, fs_info, (unsigned long)-1); 1681 if (ret) { 1682 btrfs_abort_transaction(trans, ret); 1683 goto fail; 1684 } 1685 1686 fail: 1687 pending->error = ret; 1688 dir_item_existed: 1689 trans->block_rsv = rsv; 1690 trans->bytes_reserved = 0; 1691 clear_skip_qgroup: 1692 btrfs_clear_skip_qgroup(trans); 1693 no_free_objectid: 1694 kfree(new_root_item); 1695 pending->root_item = NULL; 1696 btrfs_free_path(path); 1697 pending->path = NULL; 1698 1699 return ret; 1700 } 1701 1702 /* 1703 * create all the snapshots we've scheduled for creation 1704 */ 1705 static noinline int create_pending_snapshots(struct btrfs_trans_handle *trans, 1706 struct btrfs_fs_info *fs_info) 1707 { 1708 struct btrfs_pending_snapshot *pending, *next; 1709 struct list_head *head = &trans->transaction->pending_snapshots; 1710 int ret = 0; 1711 1712 list_for_each_entry_safe(pending, next, head, list) { 1713 list_del(&pending->list); 1714 ret = create_pending_snapshot(trans, fs_info, pending); 1715 if (ret) 1716 break; 1717 } 1718 return ret; 1719 } 1720 1721 static void update_super_roots(struct btrfs_fs_info *fs_info) 1722 { 1723 struct btrfs_root_item *root_item; 1724 struct btrfs_super_block *super; 1725 1726 super = fs_info->super_copy; 1727 1728 root_item = &fs_info->chunk_root->root_item; 1729 super->chunk_root = root_item->bytenr; 1730 super->chunk_root_generation = root_item->generation; 1731 super->chunk_root_level = root_item->level; 1732 1733 root_item = &fs_info->tree_root->root_item; 1734 super->root = root_item->bytenr; 1735 super->generation = root_item->generation; 1736 super->root_level = root_item->level; 1737 if (btrfs_test_opt(fs_info, SPACE_CACHE)) 1738 super->cache_generation = root_item->generation; 1739 if (test_bit(BTRFS_FS_UPDATE_UUID_TREE_GEN, &fs_info->flags)) 1740 super->uuid_tree_generation = root_item->generation; 1741 } 1742 1743 int btrfs_transaction_in_commit(struct btrfs_fs_info *info) 1744 { 1745 struct btrfs_transaction *trans; 1746 int ret = 0; 1747 1748 spin_lock(&info->trans_lock); 1749 trans = info->running_transaction; 1750 if (trans) 1751 ret = (trans->state >= TRANS_STATE_COMMIT_START); 1752 spin_unlock(&info->trans_lock); 1753 return ret; 1754 } 1755 1756 int btrfs_transaction_blocked(struct btrfs_fs_info *info) 1757 { 1758 struct btrfs_transaction *trans; 1759 int ret = 0; 1760 1761 spin_lock(&info->trans_lock); 1762 trans = info->running_transaction; 1763 if (trans) 1764 ret = is_transaction_blocked(trans); 1765 spin_unlock(&info->trans_lock); 1766 return ret; 1767 } 1768 1769 /* 1770 * wait for the current transaction commit to start and block subsequent 1771 * transaction joins 1772 */ 1773 static void wait_current_trans_commit_start(struct btrfs_fs_info *fs_info, 1774 struct btrfs_transaction *trans) 1775 { 1776 wait_event(fs_info->transaction_blocked_wait, 1777 trans->state >= TRANS_STATE_COMMIT_START || trans->aborted); 1778 } 1779 1780 /* 1781 * wait for the current transaction to start and then become unblocked. 1782 * caller holds ref. 1783 */ 1784 static void wait_current_trans_commit_start_and_unblock( 1785 struct btrfs_fs_info *fs_info, 1786 struct btrfs_transaction *trans) 1787 { 1788 wait_event(fs_info->transaction_wait, 1789 trans->state >= TRANS_STATE_UNBLOCKED || trans->aborted); 1790 } 1791 1792 /* 1793 * commit transactions asynchronously. once btrfs_commit_transaction_async 1794 * returns, any subsequent transaction will not be allowed to join. 1795 */ 1796 struct btrfs_async_commit { 1797 struct btrfs_trans_handle *newtrans; 1798 struct work_struct work; 1799 }; 1800 1801 static void do_async_commit(struct work_struct *work) 1802 { 1803 struct btrfs_async_commit *ac = 1804 container_of(work, struct btrfs_async_commit, work); 1805 1806 /* 1807 * We've got freeze protection passed with the transaction. 1808 * Tell lockdep about it. 1809 */ 1810 if (ac->newtrans->type & __TRANS_FREEZABLE) 1811 __sb_writers_acquired(ac->newtrans->fs_info->sb, SB_FREEZE_FS); 1812 1813 current->journal_info = ac->newtrans; 1814 1815 btrfs_commit_transaction(ac->newtrans); 1816 kfree(ac); 1817 } 1818 1819 int btrfs_commit_transaction_async(struct btrfs_trans_handle *trans, 1820 int wait_for_unblock) 1821 { 1822 struct btrfs_fs_info *fs_info = trans->fs_info; 1823 struct btrfs_async_commit *ac; 1824 struct btrfs_transaction *cur_trans; 1825 1826 ac = kmalloc(sizeof(*ac), GFP_NOFS); 1827 if (!ac) 1828 return -ENOMEM; 1829 1830 INIT_WORK(&ac->work, do_async_commit); 1831 ac->newtrans = btrfs_join_transaction(trans->root); 1832 if (IS_ERR(ac->newtrans)) { 1833 int err = PTR_ERR(ac->newtrans); 1834 kfree(ac); 1835 return err; 1836 } 1837 1838 /* take transaction reference */ 1839 cur_trans = trans->transaction; 1840 refcount_inc(&cur_trans->use_count); 1841 1842 btrfs_end_transaction(trans); 1843 1844 /* 1845 * Tell lockdep we've released the freeze rwsem, since the 1846 * async commit thread will be the one to unlock it. 1847 */ 1848 if (ac->newtrans->type & __TRANS_FREEZABLE) 1849 __sb_writers_release(fs_info->sb, SB_FREEZE_FS); 1850 1851 schedule_work(&ac->work); 1852 1853 /* wait for transaction to start and unblock */ 1854 if (wait_for_unblock) 1855 wait_current_trans_commit_start_and_unblock(fs_info, cur_trans); 1856 else 1857 wait_current_trans_commit_start(fs_info, cur_trans); 1858 1859 if (current->journal_info == trans) 1860 current->journal_info = NULL; 1861 1862 btrfs_put_transaction(cur_trans); 1863 return 0; 1864 } 1865 1866 1867 static void cleanup_transaction(struct btrfs_trans_handle *trans, 1868 struct btrfs_root *root, int err) 1869 { 1870 struct btrfs_fs_info *fs_info = root->fs_info; 1871 struct btrfs_transaction *cur_trans = trans->transaction; 1872 DEFINE_WAIT(wait); 1873 1874 WARN_ON(trans->use_count > 1); 1875 1876 btrfs_abort_transaction(trans, err); 1877 1878 spin_lock(&fs_info->trans_lock); 1879 1880 /* 1881 * If the transaction is removed from the list, it means this 1882 * transaction has been committed successfully, so it is impossible 1883 * to call the cleanup function. 1884 */ 1885 BUG_ON(list_empty(&cur_trans->list)); 1886 1887 list_del_init(&cur_trans->list); 1888 if (cur_trans == fs_info->running_transaction) { 1889 cur_trans->state = TRANS_STATE_COMMIT_DOING; 1890 spin_unlock(&fs_info->trans_lock); 1891 wait_event(cur_trans->writer_wait, 1892 atomic_read(&cur_trans->num_writers) == 1); 1893 1894 spin_lock(&fs_info->trans_lock); 1895 } 1896 spin_unlock(&fs_info->trans_lock); 1897 1898 btrfs_cleanup_one_transaction(trans->transaction, fs_info); 1899 1900 spin_lock(&fs_info->trans_lock); 1901 if (cur_trans == fs_info->running_transaction) 1902 fs_info->running_transaction = NULL; 1903 spin_unlock(&fs_info->trans_lock); 1904 1905 if (trans->type & __TRANS_FREEZABLE) 1906 sb_end_intwrite(fs_info->sb); 1907 btrfs_put_transaction(cur_trans); 1908 btrfs_put_transaction(cur_trans); 1909 1910 trace_btrfs_transaction_commit(root); 1911 1912 if (current->journal_info == trans) 1913 current->journal_info = NULL; 1914 btrfs_scrub_cancel(fs_info); 1915 1916 kmem_cache_free(btrfs_trans_handle_cachep, trans); 1917 } 1918 1919 static inline int btrfs_start_delalloc_flush(struct btrfs_fs_info *fs_info) 1920 { 1921 if (btrfs_test_opt(fs_info, FLUSHONCOMMIT)) 1922 return btrfs_start_delalloc_roots(fs_info, 1, -1); 1923 return 0; 1924 } 1925 1926 static inline void btrfs_wait_delalloc_flush(struct btrfs_fs_info *fs_info) 1927 { 1928 if (btrfs_test_opt(fs_info, FLUSHONCOMMIT)) 1929 btrfs_wait_ordered_roots(fs_info, -1, 0, (u64)-1); 1930 } 1931 1932 static inline void 1933 btrfs_wait_pending_ordered(struct btrfs_transaction *cur_trans) 1934 { 1935 wait_event(cur_trans->pending_wait, 1936 atomic_read(&cur_trans->pending_ordered) == 0); 1937 } 1938 1939 int btrfs_commit_transaction(struct btrfs_trans_handle *trans) 1940 { 1941 struct btrfs_fs_info *fs_info = trans->fs_info; 1942 struct btrfs_transaction *cur_trans = trans->transaction; 1943 struct btrfs_transaction *prev_trans = NULL; 1944 int ret; 1945 1946 /* Stop the commit early if ->aborted is set */ 1947 if (unlikely(READ_ONCE(cur_trans->aborted))) { 1948 ret = cur_trans->aborted; 1949 btrfs_end_transaction(trans); 1950 return ret; 1951 } 1952 1953 /* make a pass through all the delayed refs we have so far 1954 * any runnings procs may add more while we are here 1955 */ 1956 ret = btrfs_run_delayed_refs(trans, fs_info, 0); 1957 if (ret) { 1958 btrfs_end_transaction(trans); 1959 return ret; 1960 } 1961 1962 btrfs_trans_release_metadata(trans, fs_info); 1963 trans->block_rsv = NULL; 1964 1965 cur_trans = trans->transaction; 1966 1967 /* 1968 * set the flushing flag so procs in this transaction have to 1969 * start sending their work down. 1970 */ 1971 cur_trans->delayed_refs.flushing = 1; 1972 smp_wmb(); 1973 1974 if (!list_empty(&trans->new_bgs)) 1975 btrfs_create_pending_block_groups(trans, fs_info); 1976 1977 ret = btrfs_run_delayed_refs(trans, fs_info, 0); 1978 if (ret) { 1979 btrfs_end_transaction(trans); 1980 return ret; 1981 } 1982 1983 if (!test_bit(BTRFS_TRANS_DIRTY_BG_RUN, &cur_trans->flags)) { 1984 int run_it = 0; 1985 1986 /* this mutex is also taken before trying to set 1987 * block groups readonly. We need to make sure 1988 * that nobody has set a block group readonly 1989 * after a extents from that block group have been 1990 * allocated for cache files. btrfs_set_block_group_ro 1991 * will wait for the transaction to commit if it 1992 * finds BTRFS_TRANS_DIRTY_BG_RUN set. 1993 * 1994 * The BTRFS_TRANS_DIRTY_BG_RUN flag is also used to make sure 1995 * only one process starts all the block group IO. It wouldn't 1996 * hurt to have more than one go through, but there's no 1997 * real advantage to it either. 1998 */ 1999 mutex_lock(&fs_info->ro_block_group_mutex); 2000 if (!test_and_set_bit(BTRFS_TRANS_DIRTY_BG_RUN, 2001 &cur_trans->flags)) 2002 run_it = 1; 2003 mutex_unlock(&fs_info->ro_block_group_mutex); 2004 2005 if (run_it) 2006 ret = btrfs_start_dirty_block_groups(trans, fs_info); 2007 } 2008 if (ret) { 2009 btrfs_end_transaction(trans); 2010 return ret; 2011 } 2012 2013 spin_lock(&fs_info->trans_lock); 2014 if (cur_trans->state >= TRANS_STATE_COMMIT_START) { 2015 spin_unlock(&fs_info->trans_lock); 2016 refcount_inc(&cur_trans->use_count); 2017 ret = btrfs_end_transaction(trans); 2018 2019 wait_for_commit(cur_trans); 2020 2021 if (unlikely(cur_trans->aborted)) 2022 ret = cur_trans->aborted; 2023 2024 btrfs_put_transaction(cur_trans); 2025 2026 return ret; 2027 } 2028 2029 cur_trans->state = TRANS_STATE_COMMIT_START; 2030 wake_up(&fs_info->transaction_blocked_wait); 2031 2032 if (cur_trans->list.prev != &fs_info->trans_list) { 2033 prev_trans = list_entry(cur_trans->list.prev, 2034 struct btrfs_transaction, list); 2035 if (prev_trans->state != TRANS_STATE_COMPLETED) { 2036 refcount_inc(&prev_trans->use_count); 2037 spin_unlock(&fs_info->trans_lock); 2038 2039 wait_for_commit(prev_trans); 2040 ret = prev_trans->aborted; 2041 2042 btrfs_put_transaction(prev_trans); 2043 if (ret) 2044 goto cleanup_transaction; 2045 } else { 2046 spin_unlock(&fs_info->trans_lock); 2047 } 2048 } else { 2049 spin_unlock(&fs_info->trans_lock); 2050 } 2051 2052 extwriter_counter_dec(cur_trans, trans->type); 2053 2054 ret = btrfs_start_delalloc_flush(fs_info); 2055 if (ret) 2056 goto cleanup_transaction; 2057 2058 ret = btrfs_run_delayed_items(trans, fs_info); 2059 if (ret) 2060 goto cleanup_transaction; 2061 2062 wait_event(cur_trans->writer_wait, 2063 extwriter_counter_read(cur_trans) == 0); 2064 2065 /* some pending stuffs might be added after the previous flush. */ 2066 ret = btrfs_run_delayed_items(trans, fs_info); 2067 if (ret) 2068 goto cleanup_transaction; 2069 2070 btrfs_wait_delalloc_flush(fs_info); 2071 2072 btrfs_wait_pending_ordered(cur_trans); 2073 2074 btrfs_scrub_pause(fs_info); 2075 /* 2076 * Ok now we need to make sure to block out any other joins while we 2077 * commit the transaction. We could have started a join before setting 2078 * COMMIT_DOING so make sure to wait for num_writers to == 1 again. 2079 */ 2080 spin_lock(&fs_info->trans_lock); 2081 cur_trans->state = TRANS_STATE_COMMIT_DOING; 2082 spin_unlock(&fs_info->trans_lock); 2083 wait_event(cur_trans->writer_wait, 2084 atomic_read(&cur_trans->num_writers) == 1); 2085 2086 /* ->aborted might be set after the previous check, so check it */ 2087 if (unlikely(READ_ONCE(cur_trans->aborted))) { 2088 ret = cur_trans->aborted; 2089 goto scrub_continue; 2090 } 2091 /* 2092 * the reloc mutex makes sure that we stop 2093 * the balancing code from coming in and moving 2094 * extents around in the middle of the commit 2095 */ 2096 mutex_lock(&fs_info->reloc_mutex); 2097 2098 /* 2099 * We needn't worry about the delayed items because we will 2100 * deal with them in create_pending_snapshot(), which is the 2101 * core function of the snapshot creation. 2102 */ 2103 ret = create_pending_snapshots(trans, fs_info); 2104 if (ret) { 2105 mutex_unlock(&fs_info->reloc_mutex); 2106 goto scrub_continue; 2107 } 2108 2109 /* 2110 * We insert the dir indexes of the snapshots and update the inode 2111 * of the snapshots' parents after the snapshot creation, so there 2112 * are some delayed items which are not dealt with. Now deal with 2113 * them. 2114 * 2115 * We needn't worry that this operation will corrupt the snapshots, 2116 * because all the tree which are snapshoted will be forced to COW 2117 * the nodes and leaves. 2118 */ 2119 ret = btrfs_run_delayed_items(trans, fs_info); 2120 if (ret) { 2121 mutex_unlock(&fs_info->reloc_mutex); 2122 goto scrub_continue; 2123 } 2124 2125 ret = btrfs_run_delayed_refs(trans, fs_info, (unsigned long)-1); 2126 if (ret) { 2127 mutex_unlock(&fs_info->reloc_mutex); 2128 goto scrub_continue; 2129 } 2130 2131 /* 2132 * make sure none of the code above managed to slip in a 2133 * delayed item 2134 */ 2135 btrfs_assert_delayed_root_empty(fs_info); 2136 2137 WARN_ON(cur_trans != trans->transaction); 2138 2139 /* btrfs_commit_tree_roots is responsible for getting the 2140 * various roots consistent with each other. Every pointer 2141 * in the tree of tree roots has to point to the most up to date 2142 * root for every subvolume and other tree. So, we have to keep 2143 * the tree logging code from jumping in and changing any 2144 * of the trees. 2145 * 2146 * At this point in the commit, there can't be any tree-log 2147 * writers, but a little lower down we drop the trans mutex 2148 * and let new people in. By holding the tree_log_mutex 2149 * from now until after the super is written, we avoid races 2150 * with the tree-log code. 2151 */ 2152 mutex_lock(&fs_info->tree_log_mutex); 2153 2154 ret = commit_fs_roots(trans, fs_info); 2155 if (ret) { 2156 mutex_unlock(&fs_info->tree_log_mutex); 2157 mutex_unlock(&fs_info->reloc_mutex); 2158 goto scrub_continue; 2159 } 2160 2161 /* 2162 * Since the transaction is done, we can apply the pending changes 2163 * before the next transaction. 2164 */ 2165 btrfs_apply_pending_changes(fs_info); 2166 2167 /* commit_fs_roots gets rid of all the tree log roots, it is now 2168 * safe to free the root of tree log roots 2169 */ 2170 btrfs_free_log_root_tree(trans, fs_info); 2171 2172 /* 2173 * commit_fs_roots() can call btrfs_save_ino_cache(), which generates 2174 * new delayed refs. Must handle them or qgroup can be wrong. 2175 */ 2176 ret = btrfs_run_delayed_refs(trans, fs_info, (unsigned long)-1); 2177 if (ret) { 2178 mutex_unlock(&fs_info->tree_log_mutex); 2179 mutex_unlock(&fs_info->reloc_mutex); 2180 goto scrub_continue; 2181 } 2182 2183 ret = btrfs_qgroup_prepare_account_extents(trans, fs_info); 2184 if (ret) { 2185 mutex_unlock(&fs_info->tree_log_mutex); 2186 mutex_unlock(&fs_info->reloc_mutex); 2187 goto scrub_continue; 2188 } 2189 2190 /* 2191 * Since fs roots are all committed, we can get a quite accurate 2192 * new_roots. So let's do quota accounting. 2193 */ 2194 ret = btrfs_qgroup_account_extents(trans, fs_info); 2195 if (ret < 0) { 2196 mutex_unlock(&fs_info->tree_log_mutex); 2197 mutex_unlock(&fs_info->reloc_mutex); 2198 goto scrub_continue; 2199 } 2200 2201 ret = commit_cowonly_roots(trans, fs_info); 2202 if (ret) { 2203 mutex_unlock(&fs_info->tree_log_mutex); 2204 mutex_unlock(&fs_info->reloc_mutex); 2205 goto scrub_continue; 2206 } 2207 2208 /* 2209 * The tasks which save the space cache and inode cache may also 2210 * update ->aborted, check it. 2211 */ 2212 if (unlikely(READ_ONCE(cur_trans->aborted))) { 2213 ret = cur_trans->aborted; 2214 mutex_unlock(&fs_info->tree_log_mutex); 2215 mutex_unlock(&fs_info->reloc_mutex); 2216 goto scrub_continue; 2217 } 2218 2219 btrfs_prepare_extent_commit(fs_info); 2220 2221 cur_trans = fs_info->running_transaction; 2222 2223 btrfs_set_root_node(&fs_info->tree_root->root_item, 2224 fs_info->tree_root->node); 2225 list_add_tail(&fs_info->tree_root->dirty_list, 2226 &cur_trans->switch_commits); 2227 2228 btrfs_set_root_node(&fs_info->chunk_root->root_item, 2229 fs_info->chunk_root->node); 2230 list_add_tail(&fs_info->chunk_root->dirty_list, 2231 &cur_trans->switch_commits); 2232 2233 switch_commit_roots(cur_trans, fs_info); 2234 2235 ASSERT(list_empty(&cur_trans->dirty_bgs)); 2236 ASSERT(list_empty(&cur_trans->io_bgs)); 2237 update_super_roots(fs_info); 2238 2239 btrfs_set_super_log_root(fs_info->super_copy, 0); 2240 btrfs_set_super_log_root_level(fs_info->super_copy, 0); 2241 memcpy(fs_info->super_for_commit, fs_info->super_copy, 2242 sizeof(*fs_info->super_copy)); 2243 2244 btrfs_update_commit_device_size(fs_info); 2245 btrfs_update_commit_device_bytes_used(fs_info, cur_trans); 2246 2247 clear_bit(BTRFS_FS_LOG1_ERR, &fs_info->flags); 2248 clear_bit(BTRFS_FS_LOG2_ERR, &fs_info->flags); 2249 2250 btrfs_trans_release_chunk_metadata(trans); 2251 2252 spin_lock(&fs_info->trans_lock); 2253 cur_trans->state = TRANS_STATE_UNBLOCKED; 2254 fs_info->running_transaction = NULL; 2255 spin_unlock(&fs_info->trans_lock); 2256 mutex_unlock(&fs_info->reloc_mutex); 2257 2258 wake_up(&fs_info->transaction_wait); 2259 2260 ret = btrfs_write_and_wait_transaction(trans, fs_info); 2261 if (ret) { 2262 btrfs_handle_fs_error(fs_info, ret, 2263 "Error while writing out transaction"); 2264 mutex_unlock(&fs_info->tree_log_mutex); 2265 goto scrub_continue; 2266 } 2267 2268 ret = write_all_supers(fs_info, 0); 2269 if (ret) { 2270 mutex_unlock(&fs_info->tree_log_mutex); 2271 goto scrub_continue; 2272 } 2273 2274 /* 2275 * the super is written, we can safely allow the tree-loggers 2276 * to go about their business 2277 */ 2278 mutex_unlock(&fs_info->tree_log_mutex); 2279 2280 btrfs_finish_extent_commit(trans, fs_info); 2281 2282 if (test_bit(BTRFS_TRANS_HAVE_FREE_BGS, &cur_trans->flags)) 2283 btrfs_clear_space_info_full(fs_info); 2284 2285 fs_info->last_trans_committed = cur_trans->transid; 2286 /* 2287 * We needn't acquire the lock here because there is no other task 2288 * which can change it. 2289 */ 2290 cur_trans->state = TRANS_STATE_COMPLETED; 2291 wake_up(&cur_trans->commit_wait); 2292 2293 spin_lock(&fs_info->trans_lock); 2294 list_del_init(&cur_trans->list); 2295 spin_unlock(&fs_info->trans_lock); 2296 2297 btrfs_put_transaction(cur_trans); 2298 btrfs_put_transaction(cur_trans); 2299 2300 if (trans->type & __TRANS_FREEZABLE) 2301 sb_end_intwrite(fs_info->sb); 2302 2303 trace_btrfs_transaction_commit(trans->root); 2304 2305 btrfs_scrub_continue(fs_info); 2306 2307 if (current->journal_info == trans) 2308 current->journal_info = NULL; 2309 2310 kmem_cache_free(btrfs_trans_handle_cachep, trans); 2311 2312 /* 2313 * If fs has been frozen, we can not handle delayed iputs, otherwise 2314 * it'll result in deadlock about SB_FREEZE_FS. 2315 */ 2316 if (current != fs_info->transaction_kthread && 2317 current != fs_info->cleaner_kthread && !fs_info->fs_frozen) 2318 btrfs_run_delayed_iputs(fs_info); 2319 2320 return ret; 2321 2322 scrub_continue: 2323 btrfs_scrub_continue(fs_info); 2324 cleanup_transaction: 2325 btrfs_trans_release_metadata(trans, fs_info); 2326 btrfs_trans_release_chunk_metadata(trans); 2327 trans->block_rsv = NULL; 2328 btrfs_warn(fs_info, "Skipping commit of aborted transaction."); 2329 if (current->journal_info == trans) 2330 current->journal_info = NULL; 2331 cleanup_transaction(trans, trans->root, ret); 2332 2333 return ret; 2334 } 2335 2336 /* 2337 * return < 0 if error 2338 * 0 if there are no more dead_roots at the time of call 2339 * 1 there are more to be processed, call me again 2340 * 2341 * The return value indicates there are certainly more snapshots to delete, but 2342 * if there comes a new one during processing, it may return 0. We don't mind, 2343 * because btrfs_commit_super will poke cleaner thread and it will process it a 2344 * few seconds later. 2345 */ 2346 int btrfs_clean_one_deleted_snapshot(struct btrfs_root *root) 2347 { 2348 int ret; 2349 struct btrfs_fs_info *fs_info = root->fs_info; 2350 2351 spin_lock(&fs_info->trans_lock); 2352 if (list_empty(&fs_info->dead_roots)) { 2353 spin_unlock(&fs_info->trans_lock); 2354 return 0; 2355 } 2356 root = list_first_entry(&fs_info->dead_roots, 2357 struct btrfs_root, root_list); 2358 list_del_init(&root->root_list); 2359 spin_unlock(&fs_info->trans_lock); 2360 2361 btrfs_debug(fs_info, "cleaner removing %llu", root->objectid); 2362 2363 btrfs_kill_all_delayed_nodes(root); 2364 2365 if (btrfs_header_backref_rev(root->node) < 2366 BTRFS_MIXED_BACKREF_REV) 2367 ret = btrfs_drop_snapshot(root, NULL, 0, 0); 2368 else 2369 ret = btrfs_drop_snapshot(root, NULL, 1, 0); 2370 2371 return (ret < 0) ? 0 : 1; 2372 } 2373 2374 void btrfs_apply_pending_changes(struct btrfs_fs_info *fs_info) 2375 { 2376 unsigned long prev; 2377 unsigned long bit; 2378 2379 prev = xchg(&fs_info->pending_changes, 0); 2380 if (!prev) 2381 return; 2382 2383 bit = 1 << BTRFS_PENDING_SET_INODE_MAP_CACHE; 2384 if (prev & bit) 2385 btrfs_set_opt(fs_info->mount_opt, INODE_MAP_CACHE); 2386 prev &= ~bit; 2387 2388 bit = 1 << BTRFS_PENDING_CLEAR_INODE_MAP_CACHE; 2389 if (prev & bit) 2390 btrfs_clear_opt(fs_info->mount_opt, INODE_MAP_CACHE); 2391 prev &= ~bit; 2392 2393 bit = 1 << BTRFS_PENDING_COMMIT; 2394 if (prev & bit) 2395 btrfs_debug(fs_info, "pending commit done"); 2396 prev &= ~bit; 2397 2398 if (prev) 2399 btrfs_warn(fs_info, 2400 "unknown pending changes left 0x%lx, ignoring", prev); 2401 } 2402