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