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