1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * Copyright (C) 2007 Oracle. All rights reserved. 4 */ 5 6 #include <linux/fs.h> 7 #include <linux/slab.h> 8 #include <linux/sched.h> 9 #include <linux/sched/mm.h> 10 #include <linux/writeback.h> 11 #include <linux/pagemap.h> 12 #include <linux/blkdev.h> 13 #include <linux/uuid.h> 14 #include <linux/timekeeping.h> 15 #include "misc.h" 16 #include "ctree.h" 17 #include "disk-io.h" 18 #include "transaction.h" 19 #include "locking.h" 20 #include "tree-log.h" 21 #include "volumes.h" 22 #include "dev-replace.h" 23 #include "qgroup.h" 24 #include "block-group.h" 25 #include "space-info.h" 26 #include "zoned.h" 27 #include "fs.h" 28 #include "accessors.h" 29 #include "extent-tree.h" 30 #include "root-tree.h" 31 #include "defrag.h" 32 #include "dir-item.h" 33 #include "uuid-tree.h" 34 #include "ioctl.h" 35 #include "relocation.h" 36 #include "scrub.h" 37 38 static struct kmem_cache *btrfs_trans_handle_cachep; 39 40 #define BTRFS_ROOT_TRANS_TAG 0 41 42 /* 43 * Transaction states and transitions 44 * 45 * No running transaction (fs tree blocks are not modified) 46 * | 47 * | To next stage: 48 * | Call start_transaction() variants. Except btrfs_join_transaction_nostart(). 49 * V 50 * Transaction N [[TRANS_STATE_RUNNING]] 51 * | 52 * | New trans handles can be attached to transaction N by calling all 53 * | start_transaction() variants. 54 * | 55 * | To next stage: 56 * | Call btrfs_commit_transaction() on any trans handle attached to 57 * | transaction N 58 * V 59 * Transaction N [[TRANS_STATE_COMMIT_START]] 60 * | 61 * | Will wait for previous running transaction to completely finish if there 62 * | is one 63 * | 64 * | Then one of the following happes: 65 * | - Wait for all other trans handle holders to release. 66 * | The btrfs_commit_transaction() caller will do the commit work. 67 * | - Wait for current transaction to be committed by others. 68 * | Other btrfs_commit_transaction() caller will do the commit work. 69 * | 70 * | At this stage, only btrfs_join_transaction*() variants can attach 71 * | to this running transaction. 72 * | All other variants will wait for current one to finish and attach to 73 * | transaction N+1. 74 * | 75 * | To next stage: 76 * | Caller is chosen to commit transaction N, and all other trans handle 77 * | haven been released. 78 * V 79 * Transaction N [[TRANS_STATE_COMMIT_DOING]] 80 * | 81 * | The heavy lifting transaction work is started. 82 * | From running delayed refs (modifying extent tree) to creating pending 83 * | snapshots, running qgroups. 84 * | In short, modify supporting trees to reflect modifications of subvolume 85 * | trees. 86 * | 87 * | At this stage, all start_transaction() calls will wait for this 88 * | transaction to finish and attach to transaction N+1. 89 * | 90 * | To next stage: 91 * | Until all supporting trees are updated. 92 * V 93 * Transaction N [[TRANS_STATE_UNBLOCKED]] 94 * | Transaction N+1 95 * | All needed trees are modified, thus we only [[TRANS_STATE_RUNNING]] 96 * | need to write them back to disk and update | 97 * | super blocks. | 98 * | | 99 * | At this stage, new transaction is allowed to | 100 * | start. | 101 * | All new start_transaction() calls will be | 102 * | attached to transid N+1. | 103 * | | 104 * | To next stage: | 105 * | Until all tree blocks are super blocks are | 106 * | written to block devices | 107 * V | 108 * Transaction N [[TRANS_STATE_COMPLETED]] V 109 * All tree blocks and super blocks are written. Transaction N+1 110 * This transaction is finished and all its [[TRANS_STATE_COMMIT_START]] 111 * data structures will be cleaned up. | Life goes on 112 */ 113 static const unsigned int btrfs_blocked_trans_types[TRANS_STATE_MAX] = { 114 [TRANS_STATE_RUNNING] = 0U, 115 [TRANS_STATE_COMMIT_START] = (__TRANS_START | __TRANS_ATTACH), 116 [TRANS_STATE_COMMIT_DOING] = (__TRANS_START | 117 __TRANS_ATTACH | 118 __TRANS_JOIN | 119 __TRANS_JOIN_NOSTART), 120 [TRANS_STATE_UNBLOCKED] = (__TRANS_START | 121 __TRANS_ATTACH | 122 __TRANS_JOIN | 123 __TRANS_JOIN_NOLOCK | 124 __TRANS_JOIN_NOSTART), 125 [TRANS_STATE_SUPER_COMMITTED] = (__TRANS_START | 126 __TRANS_ATTACH | 127 __TRANS_JOIN | 128 __TRANS_JOIN_NOLOCK | 129 __TRANS_JOIN_NOSTART), 130 [TRANS_STATE_COMPLETED] = (__TRANS_START | 131 __TRANS_ATTACH | 132 __TRANS_JOIN | 133 __TRANS_JOIN_NOLOCK | 134 __TRANS_JOIN_NOSTART), 135 }; 136 137 void btrfs_put_transaction(struct btrfs_transaction *transaction) 138 { 139 WARN_ON(refcount_read(&transaction->use_count) == 0); 140 if (refcount_dec_and_test(&transaction->use_count)) { 141 BUG_ON(!list_empty(&transaction->list)); 142 WARN_ON(!RB_EMPTY_ROOT( 143 &transaction->delayed_refs.href_root.rb_root)); 144 WARN_ON(!RB_EMPTY_ROOT( 145 &transaction->delayed_refs.dirty_extent_root)); 146 if (transaction->delayed_refs.pending_csums) 147 btrfs_err(transaction->fs_info, 148 "pending csums is %llu", 149 transaction->delayed_refs.pending_csums); 150 /* 151 * If any block groups are found in ->deleted_bgs then it's 152 * because the transaction was aborted and a commit did not 153 * happen (things failed before writing the new superblock 154 * and calling btrfs_finish_extent_commit()), so we can not 155 * discard the physical locations of the block groups. 156 */ 157 while (!list_empty(&transaction->deleted_bgs)) { 158 struct btrfs_block_group *cache; 159 160 cache = list_first_entry(&transaction->deleted_bgs, 161 struct btrfs_block_group, 162 bg_list); 163 list_del_init(&cache->bg_list); 164 btrfs_unfreeze_block_group(cache); 165 btrfs_put_block_group(cache); 166 } 167 WARN_ON(!list_empty(&transaction->dev_update_list)); 168 kfree(transaction); 169 } 170 } 171 172 static noinline void switch_commit_roots(struct btrfs_trans_handle *trans) 173 { 174 struct btrfs_transaction *cur_trans = trans->transaction; 175 struct btrfs_fs_info *fs_info = trans->fs_info; 176 struct btrfs_root *root, *tmp; 177 178 /* 179 * At this point no one can be using this transaction to modify any tree 180 * and no one can start another transaction to modify any tree either. 181 */ 182 ASSERT(cur_trans->state == TRANS_STATE_COMMIT_DOING); 183 184 down_write(&fs_info->commit_root_sem); 185 186 if (test_bit(BTRFS_FS_RELOC_RUNNING, &fs_info->flags)) 187 fs_info->last_reloc_trans = trans->transid; 188 189 list_for_each_entry_safe(root, tmp, &cur_trans->switch_commits, 190 dirty_list) { 191 list_del_init(&root->dirty_list); 192 free_extent_buffer(root->commit_root); 193 root->commit_root = btrfs_root_node(root); 194 extent_io_tree_release(&root->dirty_log_pages); 195 btrfs_qgroup_clean_swapped_blocks(root); 196 } 197 198 /* We can free old roots now. */ 199 spin_lock(&cur_trans->dropped_roots_lock); 200 while (!list_empty(&cur_trans->dropped_roots)) { 201 root = list_first_entry(&cur_trans->dropped_roots, 202 struct btrfs_root, root_list); 203 list_del_init(&root->root_list); 204 spin_unlock(&cur_trans->dropped_roots_lock); 205 btrfs_free_log(trans, root); 206 btrfs_drop_and_free_fs_root(fs_info, root); 207 spin_lock(&cur_trans->dropped_roots_lock); 208 } 209 spin_unlock(&cur_trans->dropped_roots_lock); 210 211 up_write(&fs_info->commit_root_sem); 212 } 213 214 static inline void extwriter_counter_inc(struct btrfs_transaction *trans, 215 unsigned int type) 216 { 217 if (type & TRANS_EXTWRITERS) 218 atomic_inc(&trans->num_extwriters); 219 } 220 221 static inline void extwriter_counter_dec(struct btrfs_transaction *trans, 222 unsigned int type) 223 { 224 if (type & TRANS_EXTWRITERS) 225 atomic_dec(&trans->num_extwriters); 226 } 227 228 static inline void extwriter_counter_init(struct btrfs_transaction *trans, 229 unsigned int type) 230 { 231 atomic_set(&trans->num_extwriters, ((type & TRANS_EXTWRITERS) ? 1 : 0)); 232 } 233 234 static inline int extwriter_counter_read(struct btrfs_transaction *trans) 235 { 236 return atomic_read(&trans->num_extwriters); 237 } 238 239 /* 240 * To be called after doing the chunk btree updates right after allocating a new 241 * chunk (after btrfs_chunk_alloc_add_chunk_item() is called), when removing a 242 * chunk after all chunk btree updates and after finishing the second phase of 243 * chunk allocation (btrfs_create_pending_block_groups()) in case some block 244 * group had its chunk item insertion delayed to the second phase. 245 */ 246 void btrfs_trans_release_chunk_metadata(struct btrfs_trans_handle *trans) 247 { 248 struct btrfs_fs_info *fs_info = trans->fs_info; 249 250 if (!trans->chunk_bytes_reserved) 251 return; 252 253 btrfs_block_rsv_release(fs_info, &fs_info->chunk_block_rsv, 254 trans->chunk_bytes_reserved, NULL); 255 trans->chunk_bytes_reserved = 0; 256 } 257 258 /* 259 * either allocate a new transaction or hop into the existing one 260 */ 261 static noinline int join_transaction(struct btrfs_fs_info *fs_info, 262 unsigned int type) 263 { 264 struct btrfs_transaction *cur_trans; 265 266 spin_lock(&fs_info->trans_lock); 267 loop: 268 /* The file system has been taken offline. No new transactions. */ 269 if (BTRFS_FS_ERROR(fs_info)) { 270 spin_unlock(&fs_info->trans_lock); 271 return -EROFS; 272 } 273 274 cur_trans = fs_info->running_transaction; 275 if (cur_trans) { 276 if (TRANS_ABORTED(cur_trans)) { 277 spin_unlock(&fs_info->trans_lock); 278 return cur_trans->aborted; 279 } 280 if (btrfs_blocked_trans_types[cur_trans->state] & type) { 281 spin_unlock(&fs_info->trans_lock); 282 return -EBUSY; 283 } 284 refcount_inc(&cur_trans->use_count); 285 atomic_inc(&cur_trans->num_writers); 286 extwriter_counter_inc(cur_trans, type); 287 spin_unlock(&fs_info->trans_lock); 288 btrfs_lockdep_acquire(fs_info, btrfs_trans_num_writers); 289 btrfs_lockdep_acquire(fs_info, btrfs_trans_num_extwriters); 290 return 0; 291 } 292 spin_unlock(&fs_info->trans_lock); 293 294 /* 295 * If we are ATTACH, we just want to catch the current transaction, 296 * and commit it. If there is no transaction, just return ENOENT. 297 */ 298 if (type == TRANS_ATTACH) 299 return -ENOENT; 300 301 /* 302 * JOIN_NOLOCK only happens during the transaction commit, so 303 * it is impossible that ->running_transaction is NULL 304 */ 305 BUG_ON(type == TRANS_JOIN_NOLOCK); 306 307 cur_trans = kmalloc(sizeof(*cur_trans), GFP_NOFS); 308 if (!cur_trans) 309 return -ENOMEM; 310 311 btrfs_lockdep_acquire(fs_info, btrfs_trans_num_writers); 312 btrfs_lockdep_acquire(fs_info, btrfs_trans_num_extwriters); 313 314 spin_lock(&fs_info->trans_lock); 315 if (fs_info->running_transaction) { 316 /* 317 * someone started a transaction after we unlocked. Make sure 318 * to redo the checks above 319 */ 320 btrfs_lockdep_release(fs_info, btrfs_trans_num_extwriters); 321 btrfs_lockdep_release(fs_info, btrfs_trans_num_writers); 322 kfree(cur_trans); 323 goto loop; 324 } else if (BTRFS_FS_ERROR(fs_info)) { 325 spin_unlock(&fs_info->trans_lock); 326 btrfs_lockdep_release(fs_info, btrfs_trans_num_extwriters); 327 btrfs_lockdep_release(fs_info, btrfs_trans_num_writers); 328 kfree(cur_trans); 329 return -EROFS; 330 } 331 332 cur_trans->fs_info = fs_info; 333 atomic_set(&cur_trans->pending_ordered, 0); 334 init_waitqueue_head(&cur_trans->pending_wait); 335 atomic_set(&cur_trans->num_writers, 1); 336 extwriter_counter_init(cur_trans, type); 337 init_waitqueue_head(&cur_trans->writer_wait); 338 init_waitqueue_head(&cur_trans->commit_wait); 339 cur_trans->state = TRANS_STATE_RUNNING; 340 /* 341 * One for this trans handle, one so it will live on until we 342 * commit the transaction. 343 */ 344 refcount_set(&cur_trans->use_count, 2); 345 cur_trans->flags = 0; 346 cur_trans->start_time = ktime_get_seconds(); 347 348 memset(&cur_trans->delayed_refs, 0, sizeof(cur_trans->delayed_refs)); 349 350 cur_trans->delayed_refs.href_root = RB_ROOT_CACHED; 351 cur_trans->delayed_refs.dirty_extent_root = RB_ROOT; 352 atomic_set(&cur_trans->delayed_refs.num_entries, 0); 353 354 /* 355 * although the tree mod log is per file system and not per transaction, 356 * the log must never go across transaction boundaries. 357 */ 358 smp_mb(); 359 if (!list_empty(&fs_info->tree_mod_seq_list)) 360 WARN(1, KERN_ERR "BTRFS: tree_mod_seq_list not empty when creating a fresh transaction\n"); 361 if (!RB_EMPTY_ROOT(&fs_info->tree_mod_log)) 362 WARN(1, KERN_ERR "BTRFS: tree_mod_log rb tree not empty when creating a fresh transaction\n"); 363 atomic64_set(&fs_info->tree_mod_seq, 0); 364 365 spin_lock_init(&cur_trans->delayed_refs.lock); 366 367 INIT_LIST_HEAD(&cur_trans->pending_snapshots); 368 INIT_LIST_HEAD(&cur_trans->dev_update_list); 369 INIT_LIST_HEAD(&cur_trans->switch_commits); 370 INIT_LIST_HEAD(&cur_trans->dirty_bgs); 371 INIT_LIST_HEAD(&cur_trans->io_bgs); 372 INIT_LIST_HEAD(&cur_trans->dropped_roots); 373 mutex_init(&cur_trans->cache_write_mutex); 374 spin_lock_init(&cur_trans->dirty_bgs_lock); 375 INIT_LIST_HEAD(&cur_trans->deleted_bgs); 376 spin_lock_init(&cur_trans->dropped_roots_lock); 377 INIT_LIST_HEAD(&cur_trans->releasing_ebs); 378 spin_lock_init(&cur_trans->releasing_ebs_lock); 379 list_add_tail(&cur_trans->list, &fs_info->trans_list); 380 extent_io_tree_init(fs_info, &cur_trans->dirty_pages, 381 IO_TREE_TRANS_DIRTY_PAGES); 382 extent_io_tree_init(fs_info, &cur_trans->pinned_extents, 383 IO_TREE_FS_PINNED_EXTENTS); 384 fs_info->generation++; 385 cur_trans->transid = fs_info->generation; 386 fs_info->running_transaction = cur_trans; 387 cur_trans->aborted = 0; 388 spin_unlock(&fs_info->trans_lock); 389 390 return 0; 391 } 392 393 /* 394 * This does all the record keeping required to make sure that a shareable root 395 * is properly recorded in a given transaction. This is required to make sure 396 * the old root from before we joined the transaction is deleted when the 397 * transaction commits. 398 */ 399 static int record_root_in_trans(struct btrfs_trans_handle *trans, 400 struct btrfs_root *root, 401 int force) 402 { 403 struct btrfs_fs_info *fs_info = root->fs_info; 404 int ret = 0; 405 406 if ((test_bit(BTRFS_ROOT_SHAREABLE, &root->state) && 407 root->last_trans < trans->transid) || force) { 408 WARN_ON(!force && root->commit_root != root->node); 409 410 /* 411 * see below for IN_TRANS_SETUP usage rules 412 * we have the reloc mutex held now, so there 413 * is only one writer in this function 414 */ 415 set_bit(BTRFS_ROOT_IN_TRANS_SETUP, &root->state); 416 417 /* make sure readers find IN_TRANS_SETUP before 418 * they find our root->last_trans update 419 */ 420 smp_wmb(); 421 422 spin_lock(&fs_info->fs_roots_radix_lock); 423 if (root->last_trans == trans->transid && !force) { 424 spin_unlock(&fs_info->fs_roots_radix_lock); 425 return 0; 426 } 427 radix_tree_tag_set(&fs_info->fs_roots_radix, 428 (unsigned long)root->root_key.objectid, 429 BTRFS_ROOT_TRANS_TAG); 430 spin_unlock(&fs_info->fs_roots_radix_lock); 431 root->last_trans = trans->transid; 432 433 /* this is pretty tricky. We don't want to 434 * take the relocation lock in btrfs_record_root_in_trans 435 * unless we're really doing the first setup for this root in 436 * this transaction. 437 * 438 * Normally we'd use root->last_trans as a flag to decide 439 * if we want to take the expensive mutex. 440 * 441 * But, we have to set root->last_trans before we 442 * init the relocation root, otherwise, we trip over warnings 443 * in ctree.c. The solution used here is to flag ourselves 444 * with root IN_TRANS_SETUP. When this is 1, we're still 445 * fixing up the reloc trees and everyone must wait. 446 * 447 * When this is zero, they can trust root->last_trans and fly 448 * through btrfs_record_root_in_trans without having to take the 449 * lock. smp_wmb() makes sure that all the writes above are 450 * done before we pop in the zero below 451 */ 452 ret = btrfs_init_reloc_root(trans, root); 453 smp_mb__before_atomic(); 454 clear_bit(BTRFS_ROOT_IN_TRANS_SETUP, &root->state); 455 } 456 return ret; 457 } 458 459 460 void btrfs_add_dropped_root(struct btrfs_trans_handle *trans, 461 struct btrfs_root *root) 462 { 463 struct btrfs_fs_info *fs_info = root->fs_info; 464 struct btrfs_transaction *cur_trans = trans->transaction; 465 466 /* Add ourselves to the transaction dropped list */ 467 spin_lock(&cur_trans->dropped_roots_lock); 468 list_add_tail(&root->root_list, &cur_trans->dropped_roots); 469 spin_unlock(&cur_trans->dropped_roots_lock); 470 471 /* Make sure we don't try to update the root at commit time */ 472 spin_lock(&fs_info->fs_roots_radix_lock); 473 radix_tree_tag_clear(&fs_info->fs_roots_radix, 474 (unsigned long)root->root_key.objectid, 475 BTRFS_ROOT_TRANS_TAG); 476 spin_unlock(&fs_info->fs_roots_radix_lock); 477 } 478 479 int btrfs_record_root_in_trans(struct btrfs_trans_handle *trans, 480 struct btrfs_root *root) 481 { 482 struct btrfs_fs_info *fs_info = root->fs_info; 483 int ret; 484 485 if (!test_bit(BTRFS_ROOT_SHAREABLE, &root->state)) 486 return 0; 487 488 /* 489 * see record_root_in_trans for comments about IN_TRANS_SETUP usage 490 * and barriers 491 */ 492 smp_rmb(); 493 if (root->last_trans == trans->transid && 494 !test_bit(BTRFS_ROOT_IN_TRANS_SETUP, &root->state)) 495 return 0; 496 497 mutex_lock(&fs_info->reloc_mutex); 498 ret = record_root_in_trans(trans, root, 0); 499 mutex_unlock(&fs_info->reloc_mutex); 500 501 return ret; 502 } 503 504 static inline int is_transaction_blocked(struct btrfs_transaction *trans) 505 { 506 return (trans->state >= TRANS_STATE_COMMIT_START && 507 trans->state < TRANS_STATE_UNBLOCKED && 508 !TRANS_ABORTED(trans)); 509 } 510 511 /* wait for commit against the current transaction to become unblocked 512 * when this is done, it is safe to start a new transaction, but the current 513 * transaction might not be fully on disk. 514 */ 515 static void wait_current_trans(struct btrfs_fs_info *fs_info) 516 { 517 struct btrfs_transaction *cur_trans; 518 519 spin_lock(&fs_info->trans_lock); 520 cur_trans = fs_info->running_transaction; 521 if (cur_trans && is_transaction_blocked(cur_trans)) { 522 refcount_inc(&cur_trans->use_count); 523 spin_unlock(&fs_info->trans_lock); 524 525 btrfs_might_wait_for_state(fs_info, BTRFS_LOCKDEP_TRANS_UNBLOCKED); 526 wait_event(fs_info->transaction_wait, 527 cur_trans->state >= TRANS_STATE_UNBLOCKED || 528 TRANS_ABORTED(cur_trans)); 529 btrfs_put_transaction(cur_trans); 530 } else { 531 spin_unlock(&fs_info->trans_lock); 532 } 533 } 534 535 static int may_wait_transaction(struct btrfs_fs_info *fs_info, int type) 536 { 537 if (test_bit(BTRFS_FS_LOG_RECOVERING, &fs_info->flags)) 538 return 0; 539 540 if (type == TRANS_START) 541 return 1; 542 543 return 0; 544 } 545 546 static inline bool need_reserve_reloc_root(struct btrfs_root *root) 547 { 548 struct btrfs_fs_info *fs_info = root->fs_info; 549 550 if (!fs_info->reloc_ctl || 551 !test_bit(BTRFS_ROOT_SHAREABLE, &root->state) || 552 root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID || 553 root->reloc_root) 554 return false; 555 556 return true; 557 } 558 559 static struct btrfs_trans_handle * 560 start_transaction(struct btrfs_root *root, unsigned int num_items, 561 unsigned int type, enum btrfs_reserve_flush_enum flush, 562 bool enforce_qgroups) 563 { 564 struct btrfs_fs_info *fs_info = root->fs_info; 565 struct btrfs_block_rsv *delayed_refs_rsv = &fs_info->delayed_refs_rsv; 566 struct btrfs_trans_handle *h; 567 struct btrfs_transaction *cur_trans; 568 u64 num_bytes = 0; 569 u64 qgroup_reserved = 0; 570 bool reloc_reserved = false; 571 bool do_chunk_alloc = false; 572 int ret; 573 574 if (BTRFS_FS_ERROR(fs_info)) 575 return ERR_PTR(-EROFS); 576 577 if (current->journal_info) { 578 WARN_ON(type & TRANS_EXTWRITERS); 579 h = current->journal_info; 580 refcount_inc(&h->use_count); 581 WARN_ON(refcount_read(&h->use_count) > 2); 582 h->orig_rsv = h->block_rsv; 583 h->block_rsv = NULL; 584 goto got_it; 585 } 586 587 /* 588 * Do the reservation before we join the transaction so we can do all 589 * the appropriate flushing if need be. 590 */ 591 if (num_items && root != fs_info->chunk_root) { 592 struct btrfs_block_rsv *rsv = &fs_info->trans_block_rsv; 593 u64 delayed_refs_bytes = 0; 594 595 qgroup_reserved = num_items * fs_info->nodesize; 596 ret = btrfs_qgroup_reserve_meta_pertrans(root, qgroup_reserved, 597 enforce_qgroups); 598 if (ret) 599 return ERR_PTR(ret); 600 601 /* 602 * We want to reserve all the bytes we may need all at once, so 603 * we only do 1 enospc flushing cycle per transaction start. We 604 * accomplish this by simply assuming we'll do num_items worth 605 * of delayed refs updates in this trans handle, and refill that 606 * amount for whatever is missing in the reserve. 607 */ 608 num_bytes = btrfs_calc_insert_metadata_size(fs_info, num_items); 609 if (flush == BTRFS_RESERVE_FLUSH_ALL && 610 !btrfs_block_rsv_full(delayed_refs_rsv)) { 611 delayed_refs_bytes = btrfs_calc_delayed_ref_bytes(fs_info, 612 num_items); 613 num_bytes += delayed_refs_bytes; 614 } 615 616 /* 617 * Do the reservation for the relocation root creation 618 */ 619 if (need_reserve_reloc_root(root)) { 620 num_bytes += fs_info->nodesize; 621 reloc_reserved = true; 622 } 623 624 ret = btrfs_block_rsv_add(fs_info, rsv, num_bytes, flush); 625 if (ret) 626 goto reserve_fail; 627 if (delayed_refs_bytes) { 628 btrfs_migrate_to_delayed_refs_rsv(fs_info, rsv, 629 delayed_refs_bytes); 630 num_bytes -= delayed_refs_bytes; 631 } 632 633 if (rsv->space_info->force_alloc) 634 do_chunk_alloc = true; 635 } else if (num_items == 0 && flush == BTRFS_RESERVE_FLUSH_ALL && 636 !btrfs_block_rsv_full(delayed_refs_rsv)) { 637 /* 638 * Some people call with btrfs_start_transaction(root, 0) 639 * because they can be throttled, but have some other mechanism 640 * for reserving space. We still want these guys to refill the 641 * delayed block_rsv so just add 1 items worth of reservation 642 * here. 643 */ 644 ret = btrfs_delayed_refs_rsv_refill(fs_info, flush); 645 if (ret) 646 goto reserve_fail; 647 } 648 again: 649 h = kmem_cache_zalloc(btrfs_trans_handle_cachep, GFP_NOFS); 650 if (!h) { 651 ret = -ENOMEM; 652 goto alloc_fail; 653 } 654 655 /* 656 * If we are JOIN_NOLOCK we're already committing a transaction and 657 * waiting on this guy, so we don't need to do the sb_start_intwrite 658 * because we're already holding a ref. We need this because we could 659 * have raced in and did an fsync() on a file which can kick a commit 660 * and then we deadlock with somebody doing a freeze. 661 * 662 * If we are ATTACH, it means we just want to catch the current 663 * transaction and commit it, so we needn't do sb_start_intwrite(). 664 */ 665 if (type & __TRANS_FREEZABLE) 666 sb_start_intwrite(fs_info->sb); 667 668 if (may_wait_transaction(fs_info, type)) 669 wait_current_trans(fs_info); 670 671 do { 672 ret = join_transaction(fs_info, type); 673 if (ret == -EBUSY) { 674 wait_current_trans(fs_info); 675 if (unlikely(type == TRANS_ATTACH || 676 type == TRANS_JOIN_NOSTART)) 677 ret = -ENOENT; 678 } 679 } while (ret == -EBUSY); 680 681 if (ret < 0) 682 goto join_fail; 683 684 cur_trans = fs_info->running_transaction; 685 686 h->transid = cur_trans->transid; 687 h->transaction = cur_trans; 688 refcount_set(&h->use_count, 1); 689 h->fs_info = root->fs_info; 690 691 h->type = type; 692 INIT_LIST_HEAD(&h->new_bgs); 693 694 smp_mb(); 695 if (cur_trans->state >= TRANS_STATE_COMMIT_START && 696 may_wait_transaction(fs_info, type)) { 697 current->journal_info = h; 698 btrfs_commit_transaction(h); 699 goto again; 700 } 701 702 if (num_bytes) { 703 trace_btrfs_space_reservation(fs_info, "transaction", 704 h->transid, num_bytes, 1); 705 h->block_rsv = &fs_info->trans_block_rsv; 706 h->bytes_reserved = num_bytes; 707 h->reloc_reserved = reloc_reserved; 708 } 709 710 got_it: 711 if (!current->journal_info) 712 current->journal_info = h; 713 714 /* 715 * If the space_info is marked ALLOC_FORCE then we'll get upgraded to 716 * ALLOC_FORCE the first run through, and then we won't allocate for 717 * anybody else who races in later. We don't care about the return 718 * value here. 719 */ 720 if (do_chunk_alloc && num_bytes) { 721 u64 flags = h->block_rsv->space_info->flags; 722 723 btrfs_chunk_alloc(h, btrfs_get_alloc_profile(fs_info, flags), 724 CHUNK_ALLOC_NO_FORCE); 725 } 726 727 /* 728 * btrfs_record_root_in_trans() needs to alloc new extents, and may 729 * call btrfs_join_transaction() while we're also starting a 730 * transaction. 731 * 732 * Thus it need to be called after current->journal_info initialized, 733 * or we can deadlock. 734 */ 735 ret = btrfs_record_root_in_trans(h, root); 736 if (ret) { 737 /* 738 * The transaction handle is fully initialized and linked with 739 * other structures so it needs to be ended in case of errors, 740 * not just freed. 741 */ 742 btrfs_end_transaction(h); 743 return ERR_PTR(ret); 744 } 745 746 return h; 747 748 join_fail: 749 if (type & __TRANS_FREEZABLE) 750 sb_end_intwrite(fs_info->sb); 751 kmem_cache_free(btrfs_trans_handle_cachep, h); 752 alloc_fail: 753 if (num_bytes) 754 btrfs_block_rsv_release(fs_info, &fs_info->trans_block_rsv, 755 num_bytes, NULL); 756 reserve_fail: 757 btrfs_qgroup_free_meta_pertrans(root, qgroup_reserved); 758 return ERR_PTR(ret); 759 } 760 761 struct btrfs_trans_handle *btrfs_start_transaction(struct btrfs_root *root, 762 unsigned int num_items) 763 { 764 return start_transaction(root, num_items, TRANS_START, 765 BTRFS_RESERVE_FLUSH_ALL, true); 766 } 767 768 struct btrfs_trans_handle *btrfs_start_transaction_fallback_global_rsv( 769 struct btrfs_root *root, 770 unsigned int num_items) 771 { 772 return start_transaction(root, num_items, TRANS_START, 773 BTRFS_RESERVE_FLUSH_ALL_STEAL, false); 774 } 775 776 struct btrfs_trans_handle *btrfs_join_transaction(struct btrfs_root *root) 777 { 778 return start_transaction(root, 0, TRANS_JOIN, BTRFS_RESERVE_NO_FLUSH, 779 true); 780 } 781 782 struct btrfs_trans_handle *btrfs_join_transaction_spacecache(struct btrfs_root *root) 783 { 784 return start_transaction(root, 0, TRANS_JOIN_NOLOCK, 785 BTRFS_RESERVE_NO_FLUSH, true); 786 } 787 788 /* 789 * Similar to regular join but it never starts a transaction when none is 790 * running or after waiting for the current one to finish. 791 */ 792 struct btrfs_trans_handle *btrfs_join_transaction_nostart(struct btrfs_root *root) 793 { 794 return start_transaction(root, 0, TRANS_JOIN_NOSTART, 795 BTRFS_RESERVE_NO_FLUSH, true); 796 } 797 798 /* 799 * btrfs_attach_transaction() - catch the running transaction 800 * 801 * It is used when we want to commit the current the transaction, but 802 * don't want to start a new one. 803 * 804 * Note: If this function return -ENOENT, it just means there is no 805 * running transaction. But it is possible that the inactive transaction 806 * is still in the memory, not fully on disk. If you hope there is no 807 * inactive transaction in the fs when -ENOENT is returned, you should 808 * invoke 809 * btrfs_attach_transaction_barrier() 810 */ 811 struct btrfs_trans_handle *btrfs_attach_transaction(struct btrfs_root *root) 812 { 813 return start_transaction(root, 0, TRANS_ATTACH, 814 BTRFS_RESERVE_NO_FLUSH, true); 815 } 816 817 /* 818 * btrfs_attach_transaction_barrier() - catch the running transaction 819 * 820 * It is similar to the above function, the difference is this one 821 * will wait for all the inactive transactions until they fully 822 * complete. 823 */ 824 struct btrfs_trans_handle * 825 btrfs_attach_transaction_barrier(struct btrfs_root *root) 826 { 827 struct btrfs_trans_handle *trans; 828 829 trans = start_transaction(root, 0, TRANS_ATTACH, 830 BTRFS_RESERVE_NO_FLUSH, true); 831 if (trans == ERR_PTR(-ENOENT)) 832 btrfs_wait_for_commit(root->fs_info, 0); 833 834 return trans; 835 } 836 837 /* Wait for a transaction commit to reach at least the given state. */ 838 static noinline void wait_for_commit(struct btrfs_transaction *commit, 839 const enum btrfs_trans_state min_state) 840 { 841 struct btrfs_fs_info *fs_info = commit->fs_info; 842 u64 transid = commit->transid; 843 bool put = false; 844 845 /* 846 * At the moment this function is called with min_state either being 847 * TRANS_STATE_COMPLETED or TRANS_STATE_SUPER_COMMITTED. 848 */ 849 if (min_state == TRANS_STATE_COMPLETED) 850 btrfs_might_wait_for_state(fs_info, BTRFS_LOCKDEP_TRANS_COMPLETED); 851 else 852 btrfs_might_wait_for_state(fs_info, BTRFS_LOCKDEP_TRANS_SUPER_COMMITTED); 853 854 while (1) { 855 wait_event(commit->commit_wait, commit->state >= min_state); 856 if (put) 857 btrfs_put_transaction(commit); 858 859 if (min_state < TRANS_STATE_COMPLETED) 860 break; 861 862 /* 863 * A transaction isn't really completed until all of the 864 * previous transactions are completed, but with fsync we can 865 * end up with SUPER_COMMITTED transactions before a COMPLETED 866 * transaction. Wait for those. 867 */ 868 869 spin_lock(&fs_info->trans_lock); 870 commit = list_first_entry_or_null(&fs_info->trans_list, 871 struct btrfs_transaction, 872 list); 873 if (!commit || commit->transid > transid) { 874 spin_unlock(&fs_info->trans_lock); 875 break; 876 } 877 refcount_inc(&commit->use_count); 878 put = true; 879 spin_unlock(&fs_info->trans_lock); 880 } 881 } 882 883 int btrfs_wait_for_commit(struct btrfs_fs_info *fs_info, u64 transid) 884 { 885 struct btrfs_transaction *cur_trans = NULL, *t; 886 int ret = 0; 887 888 if (transid) { 889 if (transid <= fs_info->last_trans_committed) 890 goto out; 891 892 /* find specified transaction */ 893 spin_lock(&fs_info->trans_lock); 894 list_for_each_entry(t, &fs_info->trans_list, list) { 895 if (t->transid == transid) { 896 cur_trans = t; 897 refcount_inc(&cur_trans->use_count); 898 ret = 0; 899 break; 900 } 901 if (t->transid > transid) { 902 ret = 0; 903 break; 904 } 905 } 906 spin_unlock(&fs_info->trans_lock); 907 908 /* 909 * The specified transaction doesn't exist, or we 910 * raced with btrfs_commit_transaction 911 */ 912 if (!cur_trans) { 913 if (transid > fs_info->last_trans_committed) 914 ret = -EINVAL; 915 goto out; 916 } 917 } else { 918 /* find newest transaction that is committing | committed */ 919 spin_lock(&fs_info->trans_lock); 920 list_for_each_entry_reverse(t, &fs_info->trans_list, 921 list) { 922 if (t->state >= TRANS_STATE_COMMIT_START) { 923 if (t->state == TRANS_STATE_COMPLETED) 924 break; 925 cur_trans = t; 926 refcount_inc(&cur_trans->use_count); 927 break; 928 } 929 } 930 spin_unlock(&fs_info->trans_lock); 931 if (!cur_trans) 932 goto out; /* nothing committing|committed */ 933 } 934 935 wait_for_commit(cur_trans, TRANS_STATE_COMPLETED); 936 btrfs_put_transaction(cur_trans); 937 out: 938 return ret; 939 } 940 941 void btrfs_throttle(struct btrfs_fs_info *fs_info) 942 { 943 wait_current_trans(fs_info); 944 } 945 946 bool btrfs_should_end_transaction(struct btrfs_trans_handle *trans) 947 { 948 struct btrfs_transaction *cur_trans = trans->transaction; 949 950 if (cur_trans->state >= TRANS_STATE_COMMIT_START || 951 test_bit(BTRFS_DELAYED_REFS_FLUSHING, &cur_trans->delayed_refs.flags)) 952 return true; 953 954 if (btrfs_check_space_for_delayed_refs(trans->fs_info)) 955 return true; 956 957 return !!btrfs_block_rsv_check(&trans->fs_info->global_block_rsv, 50); 958 } 959 960 static void btrfs_trans_release_metadata(struct btrfs_trans_handle *trans) 961 962 { 963 struct btrfs_fs_info *fs_info = trans->fs_info; 964 965 if (!trans->block_rsv) { 966 ASSERT(!trans->bytes_reserved); 967 return; 968 } 969 970 if (!trans->bytes_reserved) 971 return; 972 973 ASSERT(trans->block_rsv == &fs_info->trans_block_rsv); 974 trace_btrfs_space_reservation(fs_info, "transaction", 975 trans->transid, trans->bytes_reserved, 0); 976 btrfs_block_rsv_release(fs_info, trans->block_rsv, 977 trans->bytes_reserved, NULL); 978 trans->bytes_reserved = 0; 979 } 980 981 static int __btrfs_end_transaction(struct btrfs_trans_handle *trans, 982 int throttle) 983 { 984 struct btrfs_fs_info *info = trans->fs_info; 985 struct btrfs_transaction *cur_trans = trans->transaction; 986 int err = 0; 987 988 if (refcount_read(&trans->use_count) > 1) { 989 refcount_dec(&trans->use_count); 990 trans->block_rsv = trans->orig_rsv; 991 return 0; 992 } 993 994 btrfs_trans_release_metadata(trans); 995 trans->block_rsv = NULL; 996 997 btrfs_create_pending_block_groups(trans); 998 999 btrfs_trans_release_chunk_metadata(trans); 1000 1001 if (trans->type & __TRANS_FREEZABLE) 1002 sb_end_intwrite(info->sb); 1003 1004 WARN_ON(cur_trans != info->running_transaction); 1005 WARN_ON(atomic_read(&cur_trans->num_writers) < 1); 1006 atomic_dec(&cur_trans->num_writers); 1007 extwriter_counter_dec(cur_trans, trans->type); 1008 1009 cond_wake_up(&cur_trans->writer_wait); 1010 1011 btrfs_lockdep_release(info, btrfs_trans_num_extwriters); 1012 btrfs_lockdep_release(info, btrfs_trans_num_writers); 1013 1014 btrfs_put_transaction(cur_trans); 1015 1016 if (current->journal_info == trans) 1017 current->journal_info = NULL; 1018 1019 if (throttle) 1020 btrfs_run_delayed_iputs(info); 1021 1022 if (TRANS_ABORTED(trans) || BTRFS_FS_ERROR(info)) { 1023 wake_up_process(info->transaction_kthread); 1024 if (TRANS_ABORTED(trans)) 1025 err = trans->aborted; 1026 else 1027 err = -EROFS; 1028 } 1029 1030 kmem_cache_free(btrfs_trans_handle_cachep, trans); 1031 return err; 1032 } 1033 1034 int btrfs_end_transaction(struct btrfs_trans_handle *trans) 1035 { 1036 return __btrfs_end_transaction(trans, 0); 1037 } 1038 1039 int btrfs_end_transaction_throttle(struct btrfs_trans_handle *trans) 1040 { 1041 return __btrfs_end_transaction(trans, 1); 1042 } 1043 1044 /* 1045 * when btree blocks are allocated, they have some corresponding bits set for 1046 * them in one of two extent_io trees. This is used to make sure all of 1047 * those extents are sent to disk but does not wait on them 1048 */ 1049 int btrfs_write_marked_extents(struct btrfs_fs_info *fs_info, 1050 struct extent_io_tree *dirty_pages, int mark) 1051 { 1052 int err = 0; 1053 int werr = 0; 1054 struct address_space *mapping = fs_info->btree_inode->i_mapping; 1055 struct extent_state *cached_state = NULL; 1056 u64 start = 0; 1057 u64 end; 1058 1059 atomic_inc(&BTRFS_I(fs_info->btree_inode)->sync_writers); 1060 while (!find_first_extent_bit(dirty_pages, start, &start, &end, 1061 mark, &cached_state)) { 1062 bool wait_writeback = false; 1063 1064 err = convert_extent_bit(dirty_pages, start, end, 1065 EXTENT_NEED_WAIT, 1066 mark, &cached_state); 1067 /* 1068 * convert_extent_bit can return -ENOMEM, which is most of the 1069 * time a temporary error. So when it happens, ignore the error 1070 * and wait for writeback of this range to finish - because we 1071 * failed to set the bit EXTENT_NEED_WAIT for the range, a call 1072 * to __btrfs_wait_marked_extents() would not know that 1073 * writeback for this range started and therefore wouldn't 1074 * wait for it to finish - we don't want to commit a 1075 * superblock that points to btree nodes/leafs for which 1076 * writeback hasn't finished yet (and without errors). 1077 * We cleanup any entries left in the io tree when committing 1078 * the transaction (through extent_io_tree_release()). 1079 */ 1080 if (err == -ENOMEM) { 1081 err = 0; 1082 wait_writeback = true; 1083 } 1084 if (!err) 1085 err = filemap_fdatawrite_range(mapping, start, end); 1086 if (err) 1087 werr = err; 1088 else if (wait_writeback) 1089 werr = filemap_fdatawait_range(mapping, start, end); 1090 free_extent_state(cached_state); 1091 cached_state = NULL; 1092 cond_resched(); 1093 start = end + 1; 1094 } 1095 atomic_dec(&BTRFS_I(fs_info->btree_inode)->sync_writers); 1096 return werr; 1097 } 1098 1099 /* 1100 * when btree blocks are allocated, they have some corresponding bits set for 1101 * them in one of two extent_io trees. This is used to make sure all of 1102 * those extents are on disk for transaction or log commit. We wait 1103 * on all the pages and clear them from the dirty pages state tree 1104 */ 1105 static int __btrfs_wait_marked_extents(struct btrfs_fs_info *fs_info, 1106 struct extent_io_tree *dirty_pages) 1107 { 1108 int err = 0; 1109 int werr = 0; 1110 struct address_space *mapping = fs_info->btree_inode->i_mapping; 1111 struct extent_state *cached_state = NULL; 1112 u64 start = 0; 1113 u64 end; 1114 1115 while (!find_first_extent_bit(dirty_pages, start, &start, &end, 1116 EXTENT_NEED_WAIT, &cached_state)) { 1117 /* 1118 * Ignore -ENOMEM errors returned by clear_extent_bit(). 1119 * When committing the transaction, we'll remove any entries 1120 * left in the io tree. For a log commit, we don't remove them 1121 * after committing the log because the tree can be accessed 1122 * concurrently - we do it only at transaction commit time when 1123 * it's safe to do it (through extent_io_tree_release()). 1124 */ 1125 err = clear_extent_bit(dirty_pages, start, end, 1126 EXTENT_NEED_WAIT, &cached_state); 1127 if (err == -ENOMEM) 1128 err = 0; 1129 if (!err) 1130 err = filemap_fdatawait_range(mapping, start, end); 1131 if (err) 1132 werr = err; 1133 free_extent_state(cached_state); 1134 cached_state = NULL; 1135 cond_resched(); 1136 start = end + 1; 1137 } 1138 if (err) 1139 werr = err; 1140 return werr; 1141 } 1142 1143 static int btrfs_wait_extents(struct btrfs_fs_info *fs_info, 1144 struct extent_io_tree *dirty_pages) 1145 { 1146 bool errors = false; 1147 int err; 1148 1149 err = __btrfs_wait_marked_extents(fs_info, dirty_pages); 1150 if (test_and_clear_bit(BTRFS_FS_BTREE_ERR, &fs_info->flags)) 1151 errors = true; 1152 1153 if (errors && !err) 1154 err = -EIO; 1155 return err; 1156 } 1157 1158 int btrfs_wait_tree_log_extents(struct btrfs_root *log_root, int mark) 1159 { 1160 struct btrfs_fs_info *fs_info = log_root->fs_info; 1161 struct extent_io_tree *dirty_pages = &log_root->dirty_log_pages; 1162 bool errors = false; 1163 int err; 1164 1165 ASSERT(log_root->root_key.objectid == BTRFS_TREE_LOG_OBJECTID); 1166 1167 err = __btrfs_wait_marked_extents(fs_info, dirty_pages); 1168 if ((mark & EXTENT_DIRTY) && 1169 test_and_clear_bit(BTRFS_FS_LOG1_ERR, &fs_info->flags)) 1170 errors = true; 1171 1172 if ((mark & EXTENT_NEW) && 1173 test_and_clear_bit(BTRFS_FS_LOG2_ERR, &fs_info->flags)) 1174 errors = true; 1175 1176 if (errors && !err) 1177 err = -EIO; 1178 return err; 1179 } 1180 1181 /* 1182 * When btree blocks are allocated the corresponding extents are marked dirty. 1183 * This function ensures such extents are persisted on disk for transaction or 1184 * log commit. 1185 * 1186 * @trans: transaction whose dirty pages we'd like to write 1187 */ 1188 static int btrfs_write_and_wait_transaction(struct btrfs_trans_handle *trans) 1189 { 1190 int ret; 1191 int ret2; 1192 struct extent_io_tree *dirty_pages = &trans->transaction->dirty_pages; 1193 struct btrfs_fs_info *fs_info = trans->fs_info; 1194 struct blk_plug plug; 1195 1196 blk_start_plug(&plug); 1197 ret = btrfs_write_marked_extents(fs_info, dirty_pages, EXTENT_DIRTY); 1198 blk_finish_plug(&plug); 1199 ret2 = btrfs_wait_extents(fs_info, dirty_pages); 1200 1201 extent_io_tree_release(&trans->transaction->dirty_pages); 1202 1203 if (ret) 1204 return ret; 1205 else if (ret2) 1206 return ret2; 1207 else 1208 return 0; 1209 } 1210 1211 /* 1212 * this is used to update the root pointer in the tree of tree roots. 1213 * 1214 * But, in the case of the extent allocation tree, updating the root 1215 * pointer may allocate blocks which may change the root of the extent 1216 * allocation tree. 1217 * 1218 * So, this loops and repeats and makes sure the cowonly root didn't 1219 * change while the root pointer was being updated in the metadata. 1220 */ 1221 static int update_cowonly_root(struct btrfs_trans_handle *trans, 1222 struct btrfs_root *root) 1223 { 1224 int ret; 1225 u64 old_root_bytenr; 1226 u64 old_root_used; 1227 struct btrfs_fs_info *fs_info = root->fs_info; 1228 struct btrfs_root *tree_root = fs_info->tree_root; 1229 1230 old_root_used = btrfs_root_used(&root->root_item); 1231 1232 while (1) { 1233 old_root_bytenr = btrfs_root_bytenr(&root->root_item); 1234 if (old_root_bytenr == root->node->start && 1235 old_root_used == btrfs_root_used(&root->root_item)) 1236 break; 1237 1238 btrfs_set_root_node(&root->root_item, root->node); 1239 ret = btrfs_update_root(trans, tree_root, 1240 &root->root_key, 1241 &root->root_item); 1242 if (ret) 1243 return ret; 1244 1245 old_root_used = btrfs_root_used(&root->root_item); 1246 } 1247 1248 return 0; 1249 } 1250 1251 /* 1252 * update all the cowonly tree roots on disk 1253 * 1254 * The error handling in this function may not be obvious. Any of the 1255 * failures will cause the file system to go offline. We still need 1256 * to clean up the delayed refs. 1257 */ 1258 static noinline int commit_cowonly_roots(struct btrfs_trans_handle *trans) 1259 { 1260 struct btrfs_fs_info *fs_info = trans->fs_info; 1261 struct list_head *dirty_bgs = &trans->transaction->dirty_bgs; 1262 struct list_head *io_bgs = &trans->transaction->io_bgs; 1263 struct list_head *next; 1264 struct extent_buffer *eb; 1265 int ret; 1266 1267 /* 1268 * At this point no one can be using this transaction to modify any tree 1269 * and no one can start another transaction to modify any tree either. 1270 */ 1271 ASSERT(trans->transaction->state == TRANS_STATE_COMMIT_DOING); 1272 1273 eb = btrfs_lock_root_node(fs_info->tree_root); 1274 ret = btrfs_cow_block(trans, fs_info->tree_root, eb, NULL, 1275 0, &eb, BTRFS_NESTING_COW); 1276 btrfs_tree_unlock(eb); 1277 free_extent_buffer(eb); 1278 1279 if (ret) 1280 return ret; 1281 1282 ret = btrfs_run_dev_stats(trans); 1283 if (ret) 1284 return ret; 1285 ret = btrfs_run_dev_replace(trans); 1286 if (ret) 1287 return ret; 1288 ret = btrfs_run_qgroups(trans); 1289 if (ret) 1290 return ret; 1291 1292 ret = btrfs_setup_space_cache(trans); 1293 if (ret) 1294 return ret; 1295 1296 again: 1297 while (!list_empty(&fs_info->dirty_cowonly_roots)) { 1298 struct btrfs_root *root; 1299 next = fs_info->dirty_cowonly_roots.next; 1300 list_del_init(next); 1301 root = list_entry(next, struct btrfs_root, dirty_list); 1302 clear_bit(BTRFS_ROOT_DIRTY, &root->state); 1303 1304 list_add_tail(&root->dirty_list, 1305 &trans->transaction->switch_commits); 1306 ret = update_cowonly_root(trans, root); 1307 if (ret) 1308 return ret; 1309 } 1310 1311 /* Now flush any delayed refs generated by updating all of the roots */ 1312 ret = btrfs_run_delayed_refs(trans, (unsigned long)-1); 1313 if (ret) 1314 return ret; 1315 1316 while (!list_empty(dirty_bgs) || !list_empty(io_bgs)) { 1317 ret = btrfs_write_dirty_block_groups(trans); 1318 if (ret) 1319 return ret; 1320 1321 /* 1322 * We're writing the dirty block groups, which could generate 1323 * delayed refs, which could generate more dirty block groups, 1324 * so we want to keep this flushing in this loop to make sure 1325 * everything gets run. 1326 */ 1327 ret = btrfs_run_delayed_refs(trans, (unsigned long)-1); 1328 if (ret) 1329 return ret; 1330 } 1331 1332 if (!list_empty(&fs_info->dirty_cowonly_roots)) 1333 goto again; 1334 1335 /* Update dev-replace pointer once everything is committed */ 1336 fs_info->dev_replace.committed_cursor_left = 1337 fs_info->dev_replace.cursor_left_last_write_of_item; 1338 1339 return 0; 1340 } 1341 1342 /* 1343 * If we had a pending drop we need to see if there are any others left in our 1344 * dead roots list, and if not clear our bit and wake any waiters. 1345 */ 1346 void btrfs_maybe_wake_unfinished_drop(struct btrfs_fs_info *fs_info) 1347 { 1348 /* 1349 * We put the drop in progress roots at the front of the list, so if the 1350 * first entry doesn't have UNFINISHED_DROP set we can wake everybody 1351 * up. 1352 */ 1353 spin_lock(&fs_info->trans_lock); 1354 if (!list_empty(&fs_info->dead_roots)) { 1355 struct btrfs_root *root = list_first_entry(&fs_info->dead_roots, 1356 struct btrfs_root, 1357 root_list); 1358 if (test_bit(BTRFS_ROOT_UNFINISHED_DROP, &root->state)) { 1359 spin_unlock(&fs_info->trans_lock); 1360 return; 1361 } 1362 } 1363 spin_unlock(&fs_info->trans_lock); 1364 1365 btrfs_wake_unfinished_drop(fs_info); 1366 } 1367 1368 /* 1369 * dead roots are old snapshots that need to be deleted. This allocates 1370 * a dirty root struct and adds it into the list of dead roots that need to 1371 * be deleted 1372 */ 1373 void btrfs_add_dead_root(struct btrfs_root *root) 1374 { 1375 struct btrfs_fs_info *fs_info = root->fs_info; 1376 1377 spin_lock(&fs_info->trans_lock); 1378 if (list_empty(&root->root_list)) { 1379 btrfs_grab_root(root); 1380 1381 /* We want to process the partially complete drops first. */ 1382 if (test_bit(BTRFS_ROOT_UNFINISHED_DROP, &root->state)) 1383 list_add(&root->root_list, &fs_info->dead_roots); 1384 else 1385 list_add_tail(&root->root_list, &fs_info->dead_roots); 1386 } 1387 spin_unlock(&fs_info->trans_lock); 1388 } 1389 1390 /* 1391 * Update each subvolume root and its relocation root, if it exists, in the tree 1392 * of tree roots. Also free log roots if they exist. 1393 */ 1394 static noinline int commit_fs_roots(struct btrfs_trans_handle *trans) 1395 { 1396 struct btrfs_fs_info *fs_info = trans->fs_info; 1397 struct btrfs_root *gang[8]; 1398 int i; 1399 int ret; 1400 1401 /* 1402 * At this point no one can be using this transaction to modify any tree 1403 * and no one can start another transaction to modify any tree either. 1404 */ 1405 ASSERT(trans->transaction->state == TRANS_STATE_COMMIT_DOING); 1406 1407 spin_lock(&fs_info->fs_roots_radix_lock); 1408 while (1) { 1409 ret = radix_tree_gang_lookup_tag(&fs_info->fs_roots_radix, 1410 (void **)gang, 0, 1411 ARRAY_SIZE(gang), 1412 BTRFS_ROOT_TRANS_TAG); 1413 if (ret == 0) 1414 break; 1415 for (i = 0; i < ret; i++) { 1416 struct btrfs_root *root = gang[i]; 1417 int ret2; 1418 1419 /* 1420 * At this point we can neither have tasks logging inodes 1421 * from a root nor trying to commit a log tree. 1422 */ 1423 ASSERT(atomic_read(&root->log_writers) == 0); 1424 ASSERT(atomic_read(&root->log_commit[0]) == 0); 1425 ASSERT(atomic_read(&root->log_commit[1]) == 0); 1426 1427 radix_tree_tag_clear(&fs_info->fs_roots_radix, 1428 (unsigned long)root->root_key.objectid, 1429 BTRFS_ROOT_TRANS_TAG); 1430 spin_unlock(&fs_info->fs_roots_radix_lock); 1431 1432 btrfs_free_log(trans, root); 1433 ret2 = btrfs_update_reloc_root(trans, root); 1434 if (ret2) 1435 return ret2; 1436 1437 /* see comments in should_cow_block() */ 1438 clear_bit(BTRFS_ROOT_FORCE_COW, &root->state); 1439 smp_mb__after_atomic(); 1440 1441 if (root->commit_root != root->node) { 1442 list_add_tail(&root->dirty_list, 1443 &trans->transaction->switch_commits); 1444 btrfs_set_root_node(&root->root_item, 1445 root->node); 1446 } 1447 1448 ret2 = btrfs_update_root(trans, fs_info->tree_root, 1449 &root->root_key, 1450 &root->root_item); 1451 if (ret2) 1452 return ret2; 1453 spin_lock(&fs_info->fs_roots_radix_lock); 1454 btrfs_qgroup_free_meta_all_pertrans(root); 1455 } 1456 } 1457 spin_unlock(&fs_info->fs_roots_radix_lock); 1458 return 0; 1459 } 1460 1461 /* 1462 * defrag a given btree. 1463 * Every leaf in the btree is read and defragged. 1464 */ 1465 int btrfs_defrag_root(struct btrfs_root *root) 1466 { 1467 struct btrfs_fs_info *info = root->fs_info; 1468 struct btrfs_trans_handle *trans; 1469 int ret; 1470 1471 if (test_and_set_bit(BTRFS_ROOT_DEFRAG_RUNNING, &root->state)) 1472 return 0; 1473 1474 while (1) { 1475 trans = btrfs_start_transaction(root, 0); 1476 if (IS_ERR(trans)) { 1477 ret = PTR_ERR(trans); 1478 break; 1479 } 1480 1481 ret = btrfs_defrag_leaves(trans, root); 1482 1483 btrfs_end_transaction(trans); 1484 btrfs_btree_balance_dirty(info); 1485 cond_resched(); 1486 1487 if (btrfs_fs_closing(info) || ret != -EAGAIN) 1488 break; 1489 1490 if (btrfs_defrag_cancelled(info)) { 1491 btrfs_debug(info, "defrag_root cancelled"); 1492 ret = -EAGAIN; 1493 break; 1494 } 1495 } 1496 clear_bit(BTRFS_ROOT_DEFRAG_RUNNING, &root->state); 1497 return ret; 1498 } 1499 1500 /* 1501 * Do all special snapshot related qgroup dirty hack. 1502 * 1503 * Will do all needed qgroup inherit and dirty hack like switch commit 1504 * roots inside one transaction and write all btree into disk, to make 1505 * qgroup works. 1506 */ 1507 static int qgroup_account_snapshot(struct btrfs_trans_handle *trans, 1508 struct btrfs_root *src, 1509 struct btrfs_root *parent, 1510 struct btrfs_qgroup_inherit *inherit, 1511 u64 dst_objectid) 1512 { 1513 struct btrfs_fs_info *fs_info = src->fs_info; 1514 int ret; 1515 1516 /* 1517 * Save some performance in the case that qgroups are not 1518 * enabled. If this check races with the ioctl, rescan will 1519 * kick in anyway. 1520 */ 1521 if (!test_bit(BTRFS_FS_QUOTA_ENABLED, &fs_info->flags)) 1522 return 0; 1523 1524 /* 1525 * Ensure dirty @src will be committed. Or, after coming 1526 * commit_fs_roots() and switch_commit_roots(), any dirty but not 1527 * recorded root will never be updated again, causing an outdated root 1528 * item. 1529 */ 1530 ret = record_root_in_trans(trans, src, 1); 1531 if (ret) 1532 return ret; 1533 1534 /* 1535 * btrfs_qgroup_inherit relies on a consistent view of the usage for the 1536 * src root, so we must run the delayed refs here. 1537 * 1538 * However this isn't particularly fool proof, because there's no 1539 * synchronization keeping us from changing the tree after this point 1540 * before we do the qgroup_inherit, or even from making changes while 1541 * we're doing the qgroup_inherit. But that's a problem for the future, 1542 * for now flush the delayed refs to narrow the race window where the 1543 * qgroup counters could end up wrong. 1544 */ 1545 ret = btrfs_run_delayed_refs(trans, (unsigned long)-1); 1546 if (ret) { 1547 btrfs_abort_transaction(trans, ret); 1548 return ret; 1549 } 1550 1551 ret = commit_fs_roots(trans); 1552 if (ret) 1553 goto out; 1554 ret = btrfs_qgroup_account_extents(trans); 1555 if (ret < 0) 1556 goto out; 1557 1558 /* Now qgroup are all updated, we can inherit it to new qgroups */ 1559 ret = btrfs_qgroup_inherit(trans, src->root_key.objectid, dst_objectid, 1560 inherit); 1561 if (ret < 0) 1562 goto out; 1563 1564 /* 1565 * Now we do a simplified commit transaction, which will: 1566 * 1) commit all subvolume and extent tree 1567 * To ensure all subvolume and extent tree have a valid 1568 * commit_root to accounting later insert_dir_item() 1569 * 2) write all btree blocks onto disk 1570 * This is to make sure later btree modification will be cowed 1571 * Or commit_root can be populated and cause wrong qgroup numbers 1572 * In this simplified commit, we don't really care about other trees 1573 * like chunk and root tree, as they won't affect qgroup. 1574 * And we don't write super to avoid half committed status. 1575 */ 1576 ret = commit_cowonly_roots(trans); 1577 if (ret) 1578 goto out; 1579 switch_commit_roots(trans); 1580 ret = btrfs_write_and_wait_transaction(trans); 1581 if (ret) 1582 btrfs_handle_fs_error(fs_info, ret, 1583 "Error while writing out transaction for qgroup"); 1584 1585 out: 1586 /* 1587 * Force parent root to be updated, as we recorded it before so its 1588 * last_trans == cur_transid. 1589 * Or it won't be committed again onto disk after later 1590 * insert_dir_item() 1591 */ 1592 if (!ret) 1593 ret = record_root_in_trans(trans, parent, 1); 1594 return ret; 1595 } 1596 1597 /* 1598 * new snapshots need to be created at a very specific time in the 1599 * transaction commit. This does the actual creation. 1600 * 1601 * Note: 1602 * If the error which may affect the commitment of the current transaction 1603 * happens, we should return the error number. If the error which just affect 1604 * the creation of the pending snapshots, just return 0. 1605 */ 1606 static noinline int create_pending_snapshot(struct btrfs_trans_handle *trans, 1607 struct btrfs_pending_snapshot *pending) 1608 { 1609 1610 struct btrfs_fs_info *fs_info = trans->fs_info; 1611 struct btrfs_key key; 1612 struct btrfs_root_item *new_root_item; 1613 struct btrfs_root *tree_root = fs_info->tree_root; 1614 struct btrfs_root *root = pending->root; 1615 struct btrfs_root *parent_root; 1616 struct btrfs_block_rsv *rsv; 1617 struct inode *parent_inode = pending->dir; 1618 struct btrfs_path *path; 1619 struct btrfs_dir_item *dir_item; 1620 struct extent_buffer *tmp; 1621 struct extent_buffer *old; 1622 struct timespec64 cur_time; 1623 int ret = 0; 1624 u64 to_reserve = 0; 1625 u64 index = 0; 1626 u64 objectid; 1627 u64 root_flags; 1628 unsigned int nofs_flags; 1629 struct fscrypt_name fname; 1630 1631 ASSERT(pending->path); 1632 path = pending->path; 1633 1634 ASSERT(pending->root_item); 1635 new_root_item = pending->root_item; 1636 1637 /* 1638 * We're inside a transaction and must make sure that any potential 1639 * allocations with GFP_KERNEL in fscrypt won't recurse back to 1640 * filesystem. 1641 */ 1642 nofs_flags = memalloc_nofs_save(); 1643 pending->error = fscrypt_setup_filename(parent_inode, 1644 &pending->dentry->d_name, 0, 1645 &fname); 1646 memalloc_nofs_restore(nofs_flags); 1647 if (pending->error) 1648 goto free_pending; 1649 1650 pending->error = btrfs_get_free_objectid(tree_root, &objectid); 1651 if (pending->error) 1652 goto free_fname; 1653 1654 /* 1655 * Make qgroup to skip current new snapshot's qgroupid, as it is 1656 * accounted by later btrfs_qgroup_inherit(). 1657 */ 1658 btrfs_set_skip_qgroup(trans, objectid); 1659 1660 btrfs_reloc_pre_snapshot(pending, &to_reserve); 1661 1662 if (to_reserve > 0) { 1663 pending->error = btrfs_block_rsv_add(fs_info, 1664 &pending->block_rsv, 1665 to_reserve, 1666 BTRFS_RESERVE_NO_FLUSH); 1667 if (pending->error) 1668 goto clear_skip_qgroup; 1669 } 1670 1671 key.objectid = objectid; 1672 key.offset = (u64)-1; 1673 key.type = BTRFS_ROOT_ITEM_KEY; 1674 1675 rsv = trans->block_rsv; 1676 trans->block_rsv = &pending->block_rsv; 1677 trans->bytes_reserved = trans->block_rsv->reserved; 1678 trace_btrfs_space_reservation(fs_info, "transaction", 1679 trans->transid, 1680 trans->bytes_reserved, 1); 1681 parent_root = BTRFS_I(parent_inode)->root; 1682 ret = record_root_in_trans(trans, parent_root, 0); 1683 if (ret) 1684 goto fail; 1685 cur_time = current_time(parent_inode); 1686 1687 /* 1688 * insert the directory item 1689 */ 1690 ret = btrfs_set_inode_index(BTRFS_I(parent_inode), &index); 1691 BUG_ON(ret); /* -ENOMEM */ 1692 1693 /* check if there is a file/dir which has the same name. */ 1694 dir_item = btrfs_lookup_dir_item(NULL, parent_root, path, 1695 btrfs_ino(BTRFS_I(parent_inode)), 1696 &fname.disk_name, 0); 1697 if (dir_item != NULL && !IS_ERR(dir_item)) { 1698 pending->error = -EEXIST; 1699 goto dir_item_existed; 1700 } else if (IS_ERR(dir_item)) { 1701 ret = PTR_ERR(dir_item); 1702 btrfs_abort_transaction(trans, ret); 1703 goto fail; 1704 } 1705 btrfs_release_path(path); 1706 1707 /* 1708 * pull in the delayed directory update 1709 * and the delayed inode item 1710 * otherwise we corrupt the FS during 1711 * snapshot 1712 */ 1713 ret = btrfs_run_delayed_items(trans); 1714 if (ret) { /* Transaction aborted */ 1715 btrfs_abort_transaction(trans, ret); 1716 goto fail; 1717 } 1718 1719 ret = record_root_in_trans(trans, root, 0); 1720 if (ret) { 1721 btrfs_abort_transaction(trans, ret); 1722 goto fail; 1723 } 1724 btrfs_set_root_last_snapshot(&root->root_item, trans->transid); 1725 memcpy(new_root_item, &root->root_item, sizeof(*new_root_item)); 1726 btrfs_check_and_init_root_item(new_root_item); 1727 1728 root_flags = btrfs_root_flags(new_root_item); 1729 if (pending->readonly) 1730 root_flags |= BTRFS_ROOT_SUBVOL_RDONLY; 1731 else 1732 root_flags &= ~BTRFS_ROOT_SUBVOL_RDONLY; 1733 btrfs_set_root_flags(new_root_item, root_flags); 1734 1735 btrfs_set_root_generation_v2(new_root_item, 1736 trans->transid); 1737 generate_random_guid(new_root_item->uuid); 1738 memcpy(new_root_item->parent_uuid, root->root_item.uuid, 1739 BTRFS_UUID_SIZE); 1740 if (!(root_flags & BTRFS_ROOT_SUBVOL_RDONLY)) { 1741 memset(new_root_item->received_uuid, 0, 1742 sizeof(new_root_item->received_uuid)); 1743 memset(&new_root_item->stime, 0, sizeof(new_root_item->stime)); 1744 memset(&new_root_item->rtime, 0, sizeof(new_root_item->rtime)); 1745 btrfs_set_root_stransid(new_root_item, 0); 1746 btrfs_set_root_rtransid(new_root_item, 0); 1747 } 1748 btrfs_set_stack_timespec_sec(&new_root_item->otime, cur_time.tv_sec); 1749 btrfs_set_stack_timespec_nsec(&new_root_item->otime, cur_time.tv_nsec); 1750 btrfs_set_root_otransid(new_root_item, trans->transid); 1751 1752 old = btrfs_lock_root_node(root); 1753 ret = btrfs_cow_block(trans, root, old, NULL, 0, &old, 1754 BTRFS_NESTING_COW); 1755 if (ret) { 1756 btrfs_tree_unlock(old); 1757 free_extent_buffer(old); 1758 btrfs_abort_transaction(trans, ret); 1759 goto fail; 1760 } 1761 1762 ret = btrfs_copy_root(trans, root, old, &tmp, objectid); 1763 /* clean up in any case */ 1764 btrfs_tree_unlock(old); 1765 free_extent_buffer(old); 1766 if (ret) { 1767 btrfs_abort_transaction(trans, ret); 1768 goto fail; 1769 } 1770 /* see comments in should_cow_block() */ 1771 set_bit(BTRFS_ROOT_FORCE_COW, &root->state); 1772 smp_wmb(); 1773 1774 btrfs_set_root_node(new_root_item, tmp); 1775 /* record when the snapshot was created in key.offset */ 1776 key.offset = trans->transid; 1777 ret = btrfs_insert_root(trans, tree_root, &key, new_root_item); 1778 btrfs_tree_unlock(tmp); 1779 free_extent_buffer(tmp); 1780 if (ret) { 1781 btrfs_abort_transaction(trans, ret); 1782 goto fail; 1783 } 1784 1785 /* 1786 * insert root back/forward references 1787 */ 1788 ret = btrfs_add_root_ref(trans, objectid, 1789 parent_root->root_key.objectid, 1790 btrfs_ino(BTRFS_I(parent_inode)), index, 1791 &fname.disk_name); 1792 if (ret) { 1793 btrfs_abort_transaction(trans, ret); 1794 goto fail; 1795 } 1796 1797 key.offset = (u64)-1; 1798 pending->snap = btrfs_get_new_fs_root(fs_info, objectid, pending->anon_dev); 1799 if (IS_ERR(pending->snap)) { 1800 ret = PTR_ERR(pending->snap); 1801 pending->snap = NULL; 1802 btrfs_abort_transaction(trans, ret); 1803 goto fail; 1804 } 1805 1806 ret = btrfs_reloc_post_snapshot(trans, pending); 1807 if (ret) { 1808 btrfs_abort_transaction(trans, ret); 1809 goto fail; 1810 } 1811 1812 /* 1813 * Do special qgroup accounting for snapshot, as we do some qgroup 1814 * snapshot hack to do fast snapshot. 1815 * To co-operate with that hack, we do hack again. 1816 * Or snapshot will be greatly slowed down by a subtree qgroup rescan 1817 */ 1818 ret = qgroup_account_snapshot(trans, root, parent_root, 1819 pending->inherit, objectid); 1820 if (ret < 0) 1821 goto fail; 1822 1823 ret = btrfs_insert_dir_item(trans, &fname.disk_name, 1824 BTRFS_I(parent_inode), &key, BTRFS_FT_DIR, 1825 index); 1826 /* We have check then name at the beginning, so it is impossible. */ 1827 BUG_ON(ret == -EEXIST || ret == -EOVERFLOW); 1828 if (ret) { 1829 btrfs_abort_transaction(trans, ret); 1830 goto fail; 1831 } 1832 1833 btrfs_i_size_write(BTRFS_I(parent_inode), parent_inode->i_size + 1834 fname.disk_name.len * 2); 1835 parent_inode->i_mtime = current_time(parent_inode); 1836 parent_inode->i_ctime = parent_inode->i_mtime; 1837 ret = btrfs_update_inode_fallback(trans, parent_root, BTRFS_I(parent_inode)); 1838 if (ret) { 1839 btrfs_abort_transaction(trans, ret); 1840 goto fail; 1841 } 1842 ret = btrfs_uuid_tree_add(trans, new_root_item->uuid, 1843 BTRFS_UUID_KEY_SUBVOL, 1844 objectid); 1845 if (ret) { 1846 btrfs_abort_transaction(trans, ret); 1847 goto fail; 1848 } 1849 if (!btrfs_is_empty_uuid(new_root_item->received_uuid)) { 1850 ret = btrfs_uuid_tree_add(trans, new_root_item->received_uuid, 1851 BTRFS_UUID_KEY_RECEIVED_SUBVOL, 1852 objectid); 1853 if (ret && ret != -EEXIST) { 1854 btrfs_abort_transaction(trans, ret); 1855 goto fail; 1856 } 1857 } 1858 1859 fail: 1860 pending->error = ret; 1861 dir_item_existed: 1862 trans->block_rsv = rsv; 1863 trans->bytes_reserved = 0; 1864 clear_skip_qgroup: 1865 btrfs_clear_skip_qgroup(trans); 1866 free_fname: 1867 fscrypt_free_filename(&fname); 1868 free_pending: 1869 kfree(new_root_item); 1870 pending->root_item = NULL; 1871 btrfs_free_path(path); 1872 pending->path = NULL; 1873 1874 return ret; 1875 } 1876 1877 /* 1878 * create all the snapshots we've scheduled for creation 1879 */ 1880 static noinline int create_pending_snapshots(struct btrfs_trans_handle *trans) 1881 { 1882 struct btrfs_pending_snapshot *pending, *next; 1883 struct list_head *head = &trans->transaction->pending_snapshots; 1884 int ret = 0; 1885 1886 list_for_each_entry_safe(pending, next, head, list) { 1887 list_del(&pending->list); 1888 ret = create_pending_snapshot(trans, pending); 1889 if (ret) 1890 break; 1891 } 1892 return ret; 1893 } 1894 1895 static void update_super_roots(struct btrfs_fs_info *fs_info) 1896 { 1897 struct btrfs_root_item *root_item; 1898 struct btrfs_super_block *super; 1899 1900 super = fs_info->super_copy; 1901 1902 root_item = &fs_info->chunk_root->root_item; 1903 super->chunk_root = root_item->bytenr; 1904 super->chunk_root_generation = root_item->generation; 1905 super->chunk_root_level = root_item->level; 1906 1907 root_item = &fs_info->tree_root->root_item; 1908 super->root = root_item->bytenr; 1909 super->generation = root_item->generation; 1910 super->root_level = root_item->level; 1911 if (btrfs_test_opt(fs_info, SPACE_CACHE)) 1912 super->cache_generation = root_item->generation; 1913 else if (test_bit(BTRFS_FS_CLEANUP_SPACE_CACHE_V1, &fs_info->flags)) 1914 super->cache_generation = 0; 1915 if (test_bit(BTRFS_FS_UPDATE_UUID_TREE_GEN, &fs_info->flags)) 1916 super->uuid_tree_generation = root_item->generation; 1917 } 1918 1919 int btrfs_transaction_in_commit(struct btrfs_fs_info *info) 1920 { 1921 struct btrfs_transaction *trans; 1922 int ret = 0; 1923 1924 spin_lock(&info->trans_lock); 1925 trans = info->running_transaction; 1926 if (trans) 1927 ret = (trans->state >= TRANS_STATE_COMMIT_START); 1928 spin_unlock(&info->trans_lock); 1929 return ret; 1930 } 1931 1932 int btrfs_transaction_blocked(struct btrfs_fs_info *info) 1933 { 1934 struct btrfs_transaction *trans; 1935 int ret = 0; 1936 1937 spin_lock(&info->trans_lock); 1938 trans = info->running_transaction; 1939 if (trans) 1940 ret = is_transaction_blocked(trans); 1941 spin_unlock(&info->trans_lock); 1942 return ret; 1943 } 1944 1945 void btrfs_commit_transaction_async(struct btrfs_trans_handle *trans) 1946 { 1947 struct btrfs_fs_info *fs_info = trans->fs_info; 1948 struct btrfs_transaction *cur_trans; 1949 1950 /* Kick the transaction kthread. */ 1951 set_bit(BTRFS_FS_COMMIT_TRANS, &fs_info->flags); 1952 wake_up_process(fs_info->transaction_kthread); 1953 1954 /* take transaction reference */ 1955 cur_trans = trans->transaction; 1956 refcount_inc(&cur_trans->use_count); 1957 1958 btrfs_end_transaction(trans); 1959 1960 /* 1961 * Wait for the current transaction commit to start and block 1962 * subsequent transaction joins 1963 */ 1964 btrfs_might_wait_for_state(fs_info, BTRFS_LOCKDEP_TRANS_COMMIT_START); 1965 wait_event(fs_info->transaction_blocked_wait, 1966 cur_trans->state >= TRANS_STATE_COMMIT_START || 1967 TRANS_ABORTED(cur_trans)); 1968 btrfs_put_transaction(cur_trans); 1969 } 1970 1971 static void cleanup_transaction(struct btrfs_trans_handle *trans, int err) 1972 { 1973 struct btrfs_fs_info *fs_info = trans->fs_info; 1974 struct btrfs_transaction *cur_trans = trans->transaction; 1975 1976 WARN_ON(refcount_read(&trans->use_count) > 1); 1977 1978 btrfs_abort_transaction(trans, err); 1979 1980 spin_lock(&fs_info->trans_lock); 1981 1982 /* 1983 * If the transaction is removed from the list, it means this 1984 * transaction has been committed successfully, so it is impossible 1985 * to call the cleanup function. 1986 */ 1987 BUG_ON(list_empty(&cur_trans->list)); 1988 1989 if (cur_trans == fs_info->running_transaction) { 1990 cur_trans->state = TRANS_STATE_COMMIT_DOING; 1991 spin_unlock(&fs_info->trans_lock); 1992 1993 /* 1994 * The thread has already released the lockdep map as reader 1995 * already in btrfs_commit_transaction(). 1996 */ 1997 btrfs_might_wait_for_event(fs_info, btrfs_trans_num_writers); 1998 wait_event(cur_trans->writer_wait, 1999 atomic_read(&cur_trans->num_writers) == 1); 2000 2001 spin_lock(&fs_info->trans_lock); 2002 } 2003 2004 /* 2005 * Now that we know no one else is still using the transaction we can 2006 * remove the transaction from the list of transactions. This avoids 2007 * the transaction kthread from cleaning up the transaction while some 2008 * other task is still using it, which could result in a use-after-free 2009 * on things like log trees, as it forces the transaction kthread to 2010 * wait for this transaction to be cleaned up by us. 2011 */ 2012 list_del_init(&cur_trans->list); 2013 2014 spin_unlock(&fs_info->trans_lock); 2015 2016 btrfs_cleanup_one_transaction(trans->transaction, fs_info); 2017 2018 spin_lock(&fs_info->trans_lock); 2019 if (cur_trans == fs_info->running_transaction) 2020 fs_info->running_transaction = NULL; 2021 spin_unlock(&fs_info->trans_lock); 2022 2023 if (trans->type & __TRANS_FREEZABLE) 2024 sb_end_intwrite(fs_info->sb); 2025 btrfs_put_transaction(cur_trans); 2026 btrfs_put_transaction(cur_trans); 2027 2028 trace_btrfs_transaction_commit(fs_info); 2029 2030 if (current->journal_info == trans) 2031 current->journal_info = NULL; 2032 2033 /* 2034 * If relocation is running, we can't cancel scrub because that will 2035 * result in a deadlock. Before relocating a block group, relocation 2036 * pauses scrub, then starts and commits a transaction before unpausing 2037 * scrub. If the transaction commit is being done by the relocation 2038 * task or triggered by another task and the relocation task is waiting 2039 * for the commit, and we end up here due to an error in the commit 2040 * path, then calling btrfs_scrub_cancel() will deadlock, as we are 2041 * asking for scrub to stop while having it asked to be paused higher 2042 * above in relocation code. 2043 */ 2044 if (!test_bit(BTRFS_FS_RELOC_RUNNING, &fs_info->flags)) 2045 btrfs_scrub_cancel(fs_info); 2046 2047 kmem_cache_free(btrfs_trans_handle_cachep, trans); 2048 } 2049 2050 /* 2051 * Release reserved delayed ref space of all pending block groups of the 2052 * transaction and remove them from the list 2053 */ 2054 static void btrfs_cleanup_pending_block_groups(struct btrfs_trans_handle *trans) 2055 { 2056 struct btrfs_fs_info *fs_info = trans->fs_info; 2057 struct btrfs_block_group *block_group, *tmp; 2058 2059 list_for_each_entry_safe(block_group, tmp, &trans->new_bgs, bg_list) { 2060 btrfs_delayed_refs_rsv_release(fs_info, 1); 2061 list_del_init(&block_group->bg_list); 2062 } 2063 } 2064 2065 static inline int btrfs_start_delalloc_flush(struct btrfs_fs_info *fs_info) 2066 { 2067 /* 2068 * We use try_to_writeback_inodes_sb() here because if we used 2069 * btrfs_start_delalloc_roots we would deadlock with fs freeze. 2070 * Currently are holding the fs freeze lock, if we do an async flush 2071 * we'll do btrfs_join_transaction() and deadlock because we need to 2072 * wait for the fs freeze lock. Using the direct flushing we benefit 2073 * from already being in a transaction and our join_transaction doesn't 2074 * have to re-take the fs freeze lock. 2075 * 2076 * Note that try_to_writeback_inodes_sb() will only trigger writeback 2077 * if it can read lock sb->s_umount. It will always be able to lock it, 2078 * except when the filesystem is being unmounted or being frozen, but in 2079 * those cases sync_filesystem() is called, which results in calling 2080 * writeback_inodes_sb() while holding a write lock on sb->s_umount. 2081 * Note that we don't call writeback_inodes_sb() directly, because it 2082 * will emit a warning if sb->s_umount is not locked. 2083 */ 2084 if (btrfs_test_opt(fs_info, FLUSHONCOMMIT)) 2085 try_to_writeback_inodes_sb(fs_info->sb, WB_REASON_SYNC); 2086 return 0; 2087 } 2088 2089 static inline void btrfs_wait_delalloc_flush(struct btrfs_fs_info *fs_info) 2090 { 2091 if (btrfs_test_opt(fs_info, FLUSHONCOMMIT)) 2092 btrfs_wait_ordered_roots(fs_info, U64_MAX, 0, (u64)-1); 2093 } 2094 2095 /* 2096 * Add a pending snapshot associated with the given transaction handle to the 2097 * respective handle. This must be called after the transaction commit started 2098 * and while holding fs_info->trans_lock. 2099 * This serves to guarantee a caller of btrfs_commit_transaction() that it can 2100 * safely free the pending snapshot pointer in case btrfs_commit_transaction() 2101 * returns an error. 2102 */ 2103 static void add_pending_snapshot(struct btrfs_trans_handle *trans) 2104 { 2105 struct btrfs_transaction *cur_trans = trans->transaction; 2106 2107 if (!trans->pending_snapshot) 2108 return; 2109 2110 lockdep_assert_held(&trans->fs_info->trans_lock); 2111 ASSERT(cur_trans->state >= TRANS_STATE_COMMIT_START); 2112 2113 list_add(&trans->pending_snapshot->list, &cur_trans->pending_snapshots); 2114 } 2115 2116 static void update_commit_stats(struct btrfs_fs_info *fs_info, ktime_t interval) 2117 { 2118 fs_info->commit_stats.commit_count++; 2119 fs_info->commit_stats.last_commit_dur = interval; 2120 fs_info->commit_stats.max_commit_dur = 2121 max_t(u64, fs_info->commit_stats.max_commit_dur, interval); 2122 fs_info->commit_stats.total_commit_dur += interval; 2123 } 2124 2125 int btrfs_commit_transaction(struct btrfs_trans_handle *trans) 2126 { 2127 struct btrfs_fs_info *fs_info = trans->fs_info; 2128 struct btrfs_transaction *cur_trans = trans->transaction; 2129 struct btrfs_transaction *prev_trans = NULL; 2130 int ret; 2131 ktime_t start_time; 2132 ktime_t interval; 2133 2134 ASSERT(refcount_read(&trans->use_count) == 1); 2135 btrfs_trans_state_lockdep_acquire(fs_info, BTRFS_LOCKDEP_TRANS_COMMIT_START); 2136 2137 clear_bit(BTRFS_FS_NEED_TRANS_COMMIT, &fs_info->flags); 2138 2139 /* Stop the commit early if ->aborted is set */ 2140 if (TRANS_ABORTED(cur_trans)) { 2141 ret = cur_trans->aborted; 2142 goto lockdep_trans_commit_start_release; 2143 } 2144 2145 btrfs_trans_release_metadata(trans); 2146 trans->block_rsv = NULL; 2147 2148 /* 2149 * We only want one transaction commit doing the flushing so we do not 2150 * waste a bunch of time on lock contention on the extent root node. 2151 */ 2152 if (!test_and_set_bit(BTRFS_DELAYED_REFS_FLUSHING, 2153 &cur_trans->delayed_refs.flags)) { 2154 /* 2155 * Make a pass through all the delayed refs we have so far. 2156 * Any running threads may add more while we are here. 2157 */ 2158 ret = btrfs_run_delayed_refs(trans, 0); 2159 if (ret) 2160 goto lockdep_trans_commit_start_release; 2161 } 2162 2163 btrfs_create_pending_block_groups(trans); 2164 2165 if (!test_bit(BTRFS_TRANS_DIRTY_BG_RUN, &cur_trans->flags)) { 2166 int run_it = 0; 2167 2168 /* this mutex is also taken before trying to set 2169 * block groups readonly. We need to make sure 2170 * that nobody has set a block group readonly 2171 * after a extents from that block group have been 2172 * allocated for cache files. btrfs_set_block_group_ro 2173 * will wait for the transaction to commit if it 2174 * finds BTRFS_TRANS_DIRTY_BG_RUN set. 2175 * 2176 * The BTRFS_TRANS_DIRTY_BG_RUN flag is also used to make sure 2177 * only one process starts all the block group IO. It wouldn't 2178 * hurt to have more than one go through, but there's no 2179 * real advantage to it either. 2180 */ 2181 mutex_lock(&fs_info->ro_block_group_mutex); 2182 if (!test_and_set_bit(BTRFS_TRANS_DIRTY_BG_RUN, 2183 &cur_trans->flags)) 2184 run_it = 1; 2185 mutex_unlock(&fs_info->ro_block_group_mutex); 2186 2187 if (run_it) { 2188 ret = btrfs_start_dirty_block_groups(trans); 2189 if (ret) 2190 goto lockdep_trans_commit_start_release; 2191 } 2192 } 2193 2194 spin_lock(&fs_info->trans_lock); 2195 if (cur_trans->state >= TRANS_STATE_COMMIT_START) { 2196 enum btrfs_trans_state want_state = TRANS_STATE_COMPLETED; 2197 2198 add_pending_snapshot(trans); 2199 2200 spin_unlock(&fs_info->trans_lock); 2201 refcount_inc(&cur_trans->use_count); 2202 2203 if (trans->in_fsync) 2204 want_state = TRANS_STATE_SUPER_COMMITTED; 2205 2206 btrfs_trans_state_lockdep_release(fs_info, 2207 BTRFS_LOCKDEP_TRANS_COMMIT_START); 2208 ret = btrfs_end_transaction(trans); 2209 wait_for_commit(cur_trans, want_state); 2210 2211 if (TRANS_ABORTED(cur_trans)) 2212 ret = cur_trans->aborted; 2213 2214 btrfs_put_transaction(cur_trans); 2215 2216 return ret; 2217 } 2218 2219 cur_trans->state = TRANS_STATE_COMMIT_START; 2220 wake_up(&fs_info->transaction_blocked_wait); 2221 btrfs_trans_state_lockdep_release(fs_info, BTRFS_LOCKDEP_TRANS_COMMIT_START); 2222 2223 if (cur_trans->list.prev != &fs_info->trans_list) { 2224 enum btrfs_trans_state want_state = TRANS_STATE_COMPLETED; 2225 2226 if (trans->in_fsync) 2227 want_state = TRANS_STATE_SUPER_COMMITTED; 2228 2229 prev_trans = list_entry(cur_trans->list.prev, 2230 struct btrfs_transaction, list); 2231 if (prev_trans->state < want_state) { 2232 refcount_inc(&prev_trans->use_count); 2233 spin_unlock(&fs_info->trans_lock); 2234 2235 wait_for_commit(prev_trans, want_state); 2236 2237 ret = READ_ONCE(prev_trans->aborted); 2238 2239 btrfs_put_transaction(prev_trans); 2240 if (ret) 2241 goto lockdep_release; 2242 } else { 2243 spin_unlock(&fs_info->trans_lock); 2244 } 2245 } else { 2246 spin_unlock(&fs_info->trans_lock); 2247 /* 2248 * The previous transaction was aborted and was already removed 2249 * from the list of transactions at fs_info->trans_list. So we 2250 * abort to prevent writing a new superblock that reflects a 2251 * corrupt state (pointing to trees with unwritten nodes/leafs). 2252 */ 2253 if (BTRFS_FS_ERROR(fs_info)) { 2254 ret = -EROFS; 2255 goto lockdep_release; 2256 } 2257 } 2258 2259 /* 2260 * Get the time spent on the work done by the commit thread and not 2261 * the time spent waiting on a previous commit 2262 */ 2263 start_time = ktime_get_ns(); 2264 2265 extwriter_counter_dec(cur_trans, trans->type); 2266 2267 ret = btrfs_start_delalloc_flush(fs_info); 2268 if (ret) 2269 goto lockdep_release; 2270 2271 ret = btrfs_run_delayed_items(trans); 2272 if (ret) 2273 goto lockdep_release; 2274 2275 /* 2276 * The thread has started/joined the transaction thus it holds the 2277 * lockdep map as a reader. It has to release it before acquiring the 2278 * lockdep map as a writer. 2279 */ 2280 btrfs_lockdep_release(fs_info, btrfs_trans_num_extwriters); 2281 btrfs_might_wait_for_event(fs_info, btrfs_trans_num_extwriters); 2282 wait_event(cur_trans->writer_wait, 2283 extwriter_counter_read(cur_trans) == 0); 2284 2285 /* some pending stuffs might be added after the previous flush. */ 2286 ret = btrfs_run_delayed_items(trans); 2287 if (ret) { 2288 btrfs_lockdep_release(fs_info, btrfs_trans_num_writers); 2289 goto cleanup_transaction; 2290 } 2291 2292 btrfs_wait_delalloc_flush(fs_info); 2293 2294 /* 2295 * Wait for all ordered extents started by a fast fsync that joined this 2296 * transaction. Otherwise if this transaction commits before the ordered 2297 * extents complete we lose logged data after a power failure. 2298 */ 2299 btrfs_might_wait_for_event(fs_info, btrfs_trans_pending_ordered); 2300 wait_event(cur_trans->pending_wait, 2301 atomic_read(&cur_trans->pending_ordered) == 0); 2302 2303 btrfs_scrub_pause(fs_info); 2304 /* 2305 * Ok now we need to make sure to block out any other joins while we 2306 * commit the transaction. We could have started a join before setting 2307 * COMMIT_DOING so make sure to wait for num_writers to == 1 again. 2308 */ 2309 spin_lock(&fs_info->trans_lock); 2310 add_pending_snapshot(trans); 2311 cur_trans->state = TRANS_STATE_COMMIT_DOING; 2312 spin_unlock(&fs_info->trans_lock); 2313 2314 /* 2315 * The thread has started/joined the transaction thus it holds the 2316 * lockdep map as a reader. It has to release it before acquiring the 2317 * lockdep map as a writer. 2318 */ 2319 btrfs_lockdep_release(fs_info, btrfs_trans_num_writers); 2320 btrfs_might_wait_for_event(fs_info, btrfs_trans_num_writers); 2321 wait_event(cur_trans->writer_wait, 2322 atomic_read(&cur_trans->num_writers) == 1); 2323 2324 /* 2325 * Make lockdep happy by acquiring the state locks after 2326 * btrfs_trans_num_writers is released. If we acquired the state locks 2327 * before releasing the btrfs_trans_num_writers lock then lockdep would 2328 * complain because we did not follow the reverse order unlocking rule. 2329 */ 2330 btrfs_trans_state_lockdep_acquire(fs_info, BTRFS_LOCKDEP_TRANS_COMPLETED); 2331 btrfs_trans_state_lockdep_acquire(fs_info, BTRFS_LOCKDEP_TRANS_SUPER_COMMITTED); 2332 btrfs_trans_state_lockdep_acquire(fs_info, BTRFS_LOCKDEP_TRANS_UNBLOCKED); 2333 2334 /* 2335 * We've started the commit, clear the flag in case we were triggered to 2336 * do an async commit but somebody else started before the transaction 2337 * kthread could do the work. 2338 */ 2339 clear_bit(BTRFS_FS_COMMIT_TRANS, &fs_info->flags); 2340 2341 if (TRANS_ABORTED(cur_trans)) { 2342 ret = cur_trans->aborted; 2343 btrfs_trans_state_lockdep_release(fs_info, BTRFS_LOCKDEP_TRANS_UNBLOCKED); 2344 goto scrub_continue; 2345 } 2346 /* 2347 * the reloc mutex makes sure that we stop 2348 * the balancing code from coming in and moving 2349 * extents around in the middle of the commit 2350 */ 2351 mutex_lock(&fs_info->reloc_mutex); 2352 2353 /* 2354 * We needn't worry about the delayed items because we will 2355 * deal with them in create_pending_snapshot(), which is the 2356 * core function of the snapshot creation. 2357 */ 2358 ret = create_pending_snapshots(trans); 2359 if (ret) 2360 goto unlock_reloc; 2361 2362 /* 2363 * We insert the dir indexes of the snapshots and update the inode 2364 * of the snapshots' parents after the snapshot creation, so there 2365 * are some delayed items which are not dealt with. Now deal with 2366 * them. 2367 * 2368 * We needn't worry that this operation will corrupt the snapshots, 2369 * because all the tree which are snapshoted will be forced to COW 2370 * the nodes and leaves. 2371 */ 2372 ret = btrfs_run_delayed_items(trans); 2373 if (ret) 2374 goto unlock_reloc; 2375 2376 ret = btrfs_run_delayed_refs(trans, (unsigned long)-1); 2377 if (ret) 2378 goto unlock_reloc; 2379 2380 /* 2381 * make sure none of the code above managed to slip in a 2382 * delayed item 2383 */ 2384 btrfs_assert_delayed_root_empty(fs_info); 2385 2386 WARN_ON(cur_trans != trans->transaction); 2387 2388 ret = commit_fs_roots(trans); 2389 if (ret) 2390 goto unlock_reloc; 2391 2392 /* commit_fs_roots gets rid of all the tree log roots, it is now 2393 * safe to free the root of tree log roots 2394 */ 2395 btrfs_free_log_root_tree(trans, fs_info); 2396 2397 /* 2398 * Since fs roots are all committed, we can get a quite accurate 2399 * new_roots. So let's do quota accounting. 2400 */ 2401 ret = btrfs_qgroup_account_extents(trans); 2402 if (ret < 0) 2403 goto unlock_reloc; 2404 2405 ret = commit_cowonly_roots(trans); 2406 if (ret) 2407 goto unlock_reloc; 2408 2409 /* 2410 * The tasks which save the space cache and inode cache may also 2411 * update ->aborted, check it. 2412 */ 2413 if (TRANS_ABORTED(cur_trans)) { 2414 ret = cur_trans->aborted; 2415 goto unlock_reloc; 2416 } 2417 2418 cur_trans = fs_info->running_transaction; 2419 2420 btrfs_set_root_node(&fs_info->tree_root->root_item, 2421 fs_info->tree_root->node); 2422 list_add_tail(&fs_info->tree_root->dirty_list, 2423 &cur_trans->switch_commits); 2424 2425 btrfs_set_root_node(&fs_info->chunk_root->root_item, 2426 fs_info->chunk_root->node); 2427 list_add_tail(&fs_info->chunk_root->dirty_list, 2428 &cur_trans->switch_commits); 2429 2430 if (btrfs_fs_incompat(fs_info, EXTENT_TREE_V2)) { 2431 btrfs_set_root_node(&fs_info->block_group_root->root_item, 2432 fs_info->block_group_root->node); 2433 list_add_tail(&fs_info->block_group_root->dirty_list, 2434 &cur_trans->switch_commits); 2435 } 2436 2437 switch_commit_roots(trans); 2438 2439 ASSERT(list_empty(&cur_trans->dirty_bgs)); 2440 ASSERT(list_empty(&cur_trans->io_bgs)); 2441 update_super_roots(fs_info); 2442 2443 btrfs_set_super_log_root(fs_info->super_copy, 0); 2444 btrfs_set_super_log_root_level(fs_info->super_copy, 0); 2445 memcpy(fs_info->super_for_commit, fs_info->super_copy, 2446 sizeof(*fs_info->super_copy)); 2447 2448 btrfs_commit_device_sizes(cur_trans); 2449 2450 clear_bit(BTRFS_FS_LOG1_ERR, &fs_info->flags); 2451 clear_bit(BTRFS_FS_LOG2_ERR, &fs_info->flags); 2452 2453 btrfs_trans_release_chunk_metadata(trans); 2454 2455 /* 2456 * Before changing the transaction state to TRANS_STATE_UNBLOCKED and 2457 * setting fs_info->running_transaction to NULL, lock tree_log_mutex to 2458 * make sure that before we commit our superblock, no other task can 2459 * start a new transaction and commit a log tree before we commit our 2460 * superblock. Anyone trying to commit a log tree locks this mutex before 2461 * writing its superblock. 2462 */ 2463 mutex_lock(&fs_info->tree_log_mutex); 2464 2465 spin_lock(&fs_info->trans_lock); 2466 cur_trans->state = TRANS_STATE_UNBLOCKED; 2467 fs_info->running_transaction = NULL; 2468 spin_unlock(&fs_info->trans_lock); 2469 mutex_unlock(&fs_info->reloc_mutex); 2470 2471 wake_up(&fs_info->transaction_wait); 2472 btrfs_trans_state_lockdep_release(fs_info, BTRFS_LOCKDEP_TRANS_UNBLOCKED); 2473 2474 /* If we have features changed, wake up the cleaner to update sysfs. */ 2475 if (test_bit(BTRFS_FS_FEATURE_CHANGED, &fs_info->flags) && 2476 fs_info->cleaner_kthread) 2477 wake_up_process(fs_info->cleaner_kthread); 2478 2479 ret = btrfs_write_and_wait_transaction(trans); 2480 if (ret) { 2481 btrfs_handle_fs_error(fs_info, ret, 2482 "Error while writing out transaction"); 2483 mutex_unlock(&fs_info->tree_log_mutex); 2484 goto scrub_continue; 2485 } 2486 2487 /* 2488 * At this point, we should have written all the tree blocks allocated 2489 * in this transaction. So it's now safe to free the redirtyied extent 2490 * buffers. 2491 */ 2492 btrfs_free_redirty_list(cur_trans); 2493 2494 ret = write_all_supers(fs_info, 0); 2495 /* 2496 * the super is written, we can safely allow the tree-loggers 2497 * to go about their business 2498 */ 2499 mutex_unlock(&fs_info->tree_log_mutex); 2500 if (ret) 2501 goto scrub_continue; 2502 2503 /* 2504 * We needn't acquire the lock here because there is no other task 2505 * which can change it. 2506 */ 2507 cur_trans->state = TRANS_STATE_SUPER_COMMITTED; 2508 wake_up(&cur_trans->commit_wait); 2509 btrfs_trans_state_lockdep_release(fs_info, BTRFS_LOCKDEP_TRANS_SUPER_COMMITTED); 2510 2511 btrfs_finish_extent_commit(trans); 2512 2513 if (test_bit(BTRFS_TRANS_HAVE_FREE_BGS, &cur_trans->flags)) 2514 btrfs_clear_space_info_full(fs_info); 2515 2516 fs_info->last_trans_committed = cur_trans->transid; 2517 /* 2518 * We needn't acquire the lock here because there is no other task 2519 * which can change it. 2520 */ 2521 cur_trans->state = TRANS_STATE_COMPLETED; 2522 wake_up(&cur_trans->commit_wait); 2523 btrfs_trans_state_lockdep_release(fs_info, BTRFS_LOCKDEP_TRANS_COMPLETED); 2524 2525 spin_lock(&fs_info->trans_lock); 2526 list_del_init(&cur_trans->list); 2527 spin_unlock(&fs_info->trans_lock); 2528 2529 btrfs_put_transaction(cur_trans); 2530 btrfs_put_transaction(cur_trans); 2531 2532 if (trans->type & __TRANS_FREEZABLE) 2533 sb_end_intwrite(fs_info->sb); 2534 2535 trace_btrfs_transaction_commit(fs_info); 2536 2537 interval = ktime_get_ns() - start_time; 2538 2539 btrfs_scrub_continue(fs_info); 2540 2541 if (current->journal_info == trans) 2542 current->journal_info = NULL; 2543 2544 kmem_cache_free(btrfs_trans_handle_cachep, trans); 2545 2546 update_commit_stats(fs_info, interval); 2547 2548 return ret; 2549 2550 unlock_reloc: 2551 mutex_unlock(&fs_info->reloc_mutex); 2552 btrfs_trans_state_lockdep_release(fs_info, BTRFS_LOCKDEP_TRANS_UNBLOCKED); 2553 scrub_continue: 2554 btrfs_trans_state_lockdep_release(fs_info, BTRFS_LOCKDEP_TRANS_SUPER_COMMITTED); 2555 btrfs_trans_state_lockdep_release(fs_info, BTRFS_LOCKDEP_TRANS_COMPLETED); 2556 btrfs_scrub_continue(fs_info); 2557 cleanup_transaction: 2558 btrfs_trans_release_metadata(trans); 2559 btrfs_cleanup_pending_block_groups(trans); 2560 btrfs_trans_release_chunk_metadata(trans); 2561 trans->block_rsv = NULL; 2562 btrfs_warn(fs_info, "Skipping commit of aborted transaction."); 2563 if (current->journal_info == trans) 2564 current->journal_info = NULL; 2565 cleanup_transaction(trans, ret); 2566 2567 return ret; 2568 2569 lockdep_release: 2570 btrfs_lockdep_release(fs_info, btrfs_trans_num_extwriters); 2571 btrfs_lockdep_release(fs_info, btrfs_trans_num_writers); 2572 goto cleanup_transaction; 2573 2574 lockdep_trans_commit_start_release: 2575 btrfs_trans_state_lockdep_release(fs_info, BTRFS_LOCKDEP_TRANS_COMMIT_START); 2576 btrfs_end_transaction(trans); 2577 return ret; 2578 } 2579 2580 /* 2581 * return < 0 if error 2582 * 0 if there are no more dead_roots at the time of call 2583 * 1 there are more to be processed, call me again 2584 * 2585 * The return value indicates there are certainly more snapshots to delete, but 2586 * if there comes a new one during processing, it may return 0. We don't mind, 2587 * because btrfs_commit_super will poke cleaner thread and it will process it a 2588 * few seconds later. 2589 */ 2590 int btrfs_clean_one_deleted_snapshot(struct btrfs_fs_info *fs_info) 2591 { 2592 struct btrfs_root *root; 2593 int ret; 2594 2595 spin_lock(&fs_info->trans_lock); 2596 if (list_empty(&fs_info->dead_roots)) { 2597 spin_unlock(&fs_info->trans_lock); 2598 return 0; 2599 } 2600 root = list_first_entry(&fs_info->dead_roots, 2601 struct btrfs_root, root_list); 2602 list_del_init(&root->root_list); 2603 spin_unlock(&fs_info->trans_lock); 2604 2605 btrfs_debug(fs_info, "cleaner removing %llu", root->root_key.objectid); 2606 2607 btrfs_kill_all_delayed_nodes(root); 2608 2609 if (btrfs_header_backref_rev(root->node) < 2610 BTRFS_MIXED_BACKREF_REV) 2611 ret = btrfs_drop_snapshot(root, 0, 0); 2612 else 2613 ret = btrfs_drop_snapshot(root, 1, 0); 2614 2615 btrfs_put_root(root); 2616 return (ret < 0) ? 0 : 1; 2617 } 2618 2619 /* 2620 * We only mark the transaction aborted and then set the file system read-only. 2621 * This will prevent new transactions from starting or trying to join this 2622 * one. 2623 * 2624 * This means that error recovery at the call site is limited to freeing 2625 * any local memory allocations and passing the error code up without 2626 * further cleanup. The transaction should complete as it normally would 2627 * in the call path but will return -EIO. 2628 * 2629 * We'll complete the cleanup in btrfs_end_transaction and 2630 * btrfs_commit_transaction. 2631 */ 2632 void __cold __btrfs_abort_transaction(struct btrfs_trans_handle *trans, 2633 const char *function, 2634 unsigned int line, int errno, bool first_hit) 2635 { 2636 struct btrfs_fs_info *fs_info = trans->fs_info; 2637 2638 WRITE_ONCE(trans->aborted, errno); 2639 WRITE_ONCE(trans->transaction->aborted, errno); 2640 if (first_hit && errno == -ENOSPC) 2641 btrfs_dump_space_info_for_trans_abort(fs_info); 2642 /* Wake up anybody who may be waiting on this transaction */ 2643 wake_up(&fs_info->transaction_wait); 2644 wake_up(&fs_info->transaction_blocked_wait); 2645 __btrfs_handle_fs_error(fs_info, function, line, errno, NULL); 2646 } 2647 2648 int __init btrfs_transaction_init(void) 2649 { 2650 btrfs_trans_handle_cachep = kmem_cache_create("btrfs_trans_handle", 2651 sizeof(struct btrfs_trans_handle), 0, 2652 SLAB_TEMPORARY | SLAB_MEM_SPREAD, NULL); 2653 if (!btrfs_trans_handle_cachep) 2654 return -ENOMEM; 2655 return 0; 2656 } 2657 2658 void __cold btrfs_transaction_exit(void) 2659 { 2660 kmem_cache_destroy(btrfs_trans_handle_cachep); 2661 } 2662