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