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 "fs.h" 27 #include "accessors.h" 28 #include "extent-tree.h" 29 #include "root-tree.h" 30 #include "dir-item.h" 31 #include "uuid-tree.h" 32 #include "ioctl.h" 33 #include "relocation.h" 34 #include "scrub.h" 35 36 static struct kmem_cache *btrfs_trans_handle_cachep; 37 38 /* 39 * Transaction states and transitions 40 * 41 * No running transaction (fs tree blocks are not modified) 42 * | 43 * | To next stage: 44 * | Call start_transaction() variants. Except btrfs_join_transaction_nostart(). 45 * V 46 * Transaction N [[TRANS_STATE_RUNNING]] 47 * | 48 * | New trans handles can be attached to transaction N by calling all 49 * | start_transaction() variants. 50 * | 51 * | To next stage: 52 * | Call btrfs_commit_transaction() on any trans handle attached to 53 * | transaction N 54 * V 55 * Transaction N [[TRANS_STATE_COMMIT_PREP]] 56 * | 57 * | If there are simultaneous calls to btrfs_commit_transaction() one will win 58 * | the race and the rest will wait for the winner to commit the transaction. 59 * | 60 * | The winner will wait for previous running transaction to completely finish 61 * | if there is one. 62 * | 63 * Transaction N [[TRANS_STATE_COMMIT_START]] 64 * | 65 * | Then one of the following happens: 66 * | - Wait for all other trans handle holders to release. 67 * | The btrfs_commit_transaction() caller will do the commit work. 68 * | - Wait for current transaction to be committed by others. 69 * | Other btrfs_commit_transaction() caller will do the commit work. 70 * | 71 * | At this stage, only btrfs_join_transaction*() variants can attach 72 * | to this running transaction. 73 * | All other variants will wait for current one to finish and attach to 74 * | transaction N+1. 75 * | 76 * | To next stage: 77 * | Caller is chosen to commit transaction N, and all other trans handle 78 * | haven been released. 79 * V 80 * Transaction N [[TRANS_STATE_COMMIT_DOING]] 81 * | 82 * | The heavy lifting transaction work is started. 83 * | From running delayed refs (modifying extent tree) to creating pending 84 * | snapshots, running qgroups. 85 * | In short, modify supporting trees to reflect modifications of subvolume 86 * | trees. 87 * | 88 * | At this stage, all start_transaction() calls will wait for this 89 * | transaction to finish and attach to transaction N+1. 90 * | 91 * | To next stage: 92 * | Until all supporting trees are updated. 93 * V 94 * Transaction N [[TRANS_STATE_UNBLOCKED]] 95 * | Transaction N+1 96 * | All needed trees are modified, thus we only [[TRANS_STATE_RUNNING]] 97 * | need to write them back to disk and update | 98 * | super blocks. | 99 * | | 100 * | At this stage, new transaction is allowed to | 101 * | start. | 102 * | All new start_transaction() calls will be | 103 * | attached to transid N+1. | 104 * | | 105 * | To next stage: | 106 * | Until all tree blocks are super blocks are | 107 * | written to block devices | 108 * V | 109 * Transaction N [[TRANS_STATE_COMPLETED]] V 110 * All tree blocks and super blocks are written. Transaction N+1 111 * This transaction is finished and all its [[TRANS_STATE_COMMIT_START]] 112 * data structures will be cleaned up. | Life goes on 113 */ 114 static const unsigned int btrfs_blocked_trans_types[TRANS_STATE_MAX] = { 115 [TRANS_STATE_RUNNING] = 0U, 116 [TRANS_STATE_COMMIT_PREP] = 0U, 117 [TRANS_STATE_COMMIT_START] = (__TRANS_START | __TRANS_ATTACH), 118 [TRANS_STATE_COMMIT_DOING] = (__TRANS_START | 119 __TRANS_ATTACH | 120 __TRANS_JOIN | 121 __TRANS_JOIN_NOSTART), 122 [TRANS_STATE_UNBLOCKED] = (__TRANS_START | 123 __TRANS_ATTACH | 124 __TRANS_JOIN | 125 __TRANS_JOIN_NOLOCK | 126 __TRANS_JOIN_NOSTART), 127 [TRANS_STATE_SUPER_COMMITTED] = (__TRANS_START | 128 __TRANS_ATTACH | 129 __TRANS_JOIN | 130 __TRANS_JOIN_NOLOCK | 131 __TRANS_JOIN_NOSTART), 132 [TRANS_STATE_COMPLETED] = (__TRANS_START | 133 __TRANS_ATTACH | 134 __TRANS_JOIN | 135 __TRANS_JOIN_NOLOCK | 136 __TRANS_JOIN_NOSTART), 137 }; 138 139 void btrfs_put_transaction(struct btrfs_transaction *transaction) 140 { 141 WARN_ON(refcount_read(&transaction->use_count) == 0); 142 if (refcount_dec_and_test(&transaction->use_count)) { 143 BUG_ON(!list_empty(&transaction->list)); 144 WARN_ON(!xa_empty(&transaction->delayed_refs.head_refs)); 145 WARN_ON(!xa_empty(&transaction->delayed_refs.dirty_extents)); 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 or TRANS_JOIN_NOSTART, we just want to catch the 296 * current transaction, and commit it. If there is no transaction, just 297 * return ENOENT. 298 */ 299 if (type == TRANS_ATTACH || type == TRANS_JOIN_NOSTART) 300 return -ENOENT; 301 302 /* 303 * JOIN_NOLOCK only happens during the transaction commit, so 304 * it is impossible that ->running_transaction is NULL 305 */ 306 BUG_ON(type == TRANS_JOIN_NOLOCK); 307 308 cur_trans = kmalloc(sizeof(*cur_trans), GFP_NOFS); 309 if (!cur_trans) 310 return -ENOMEM; 311 312 btrfs_lockdep_acquire(fs_info, btrfs_trans_num_writers); 313 btrfs_lockdep_acquire(fs_info, btrfs_trans_num_extwriters); 314 315 spin_lock(&fs_info->trans_lock); 316 if (fs_info->running_transaction) { 317 /* 318 * someone started a transaction after we unlocked. Make sure 319 * to redo the checks above 320 */ 321 btrfs_lockdep_release(fs_info, btrfs_trans_num_extwriters); 322 btrfs_lockdep_release(fs_info, btrfs_trans_num_writers); 323 kfree(cur_trans); 324 goto loop; 325 } else if (BTRFS_FS_ERROR(fs_info)) { 326 spin_unlock(&fs_info->trans_lock); 327 btrfs_lockdep_release(fs_info, btrfs_trans_num_extwriters); 328 btrfs_lockdep_release(fs_info, btrfs_trans_num_writers); 329 kfree(cur_trans); 330 return -EROFS; 331 } 332 333 cur_trans->fs_info = fs_info; 334 atomic_set(&cur_trans->pending_ordered, 0); 335 init_waitqueue_head(&cur_trans->pending_wait); 336 atomic_set(&cur_trans->num_writers, 1); 337 extwriter_counter_init(cur_trans, type); 338 init_waitqueue_head(&cur_trans->writer_wait); 339 init_waitqueue_head(&cur_trans->commit_wait); 340 cur_trans->state = TRANS_STATE_RUNNING; 341 /* 342 * One for this trans handle, one so it will live on until we 343 * commit the transaction. 344 */ 345 refcount_set(&cur_trans->use_count, 2); 346 cur_trans->flags = 0; 347 cur_trans->start_time = ktime_get_seconds(); 348 349 memset(&cur_trans->delayed_refs, 0, sizeof(cur_trans->delayed_refs)); 350 351 xa_init(&cur_trans->delayed_refs.head_refs); 352 xa_init(&cur_trans->delayed_refs.dirty_extents); 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 btrfs_set_fs_generation(fs_info, fs_info->generation + 1); 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 btrfs_get_root_last_trans(root) < 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 (btrfs_get_root_last_trans(root) == 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)btrfs_root_id(root), 427 BTRFS_ROOT_TRANS_TAG); 428 spin_unlock(&fs_info->fs_roots_radix_lock); 429 btrfs_set_root_last_trans(root, 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)btrfs_root_id(root), 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 (btrfs_get_root_last_trans(root) == 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 btrfs_root_id(root) == BTRFS_TREE_RELOC_OBJECTID || 551 root->reloc_root) 552 return false; 553 554 return true; 555 } 556 557 static int btrfs_reserve_trans_metadata(struct btrfs_fs_info *fs_info, 558 enum btrfs_reserve_flush_enum flush, 559 u64 num_bytes, 560 u64 *delayed_refs_bytes) 561 { 562 struct btrfs_space_info *si = fs_info->trans_block_rsv.space_info; 563 u64 bytes = num_bytes + *delayed_refs_bytes; 564 int ret; 565 566 /* 567 * We want to reserve all the bytes we may need all at once, so we only 568 * do 1 enospc flushing cycle per transaction start. 569 */ 570 ret = btrfs_reserve_metadata_bytes(fs_info, si, bytes, flush); 571 572 /* 573 * If we are an emergency flush, which can steal from the global block 574 * reserve, then attempt to not reserve space for the delayed refs, as 575 * we will consume space for them from the global block reserve. 576 */ 577 if (ret && flush == BTRFS_RESERVE_FLUSH_ALL_STEAL) { 578 bytes -= *delayed_refs_bytes; 579 *delayed_refs_bytes = 0; 580 ret = btrfs_reserve_metadata_bytes(fs_info, si, bytes, flush); 581 } 582 583 return ret; 584 } 585 586 static struct btrfs_trans_handle * 587 start_transaction(struct btrfs_root *root, unsigned int num_items, 588 unsigned int type, enum btrfs_reserve_flush_enum flush, 589 bool enforce_qgroups) 590 { 591 struct btrfs_fs_info *fs_info = root->fs_info; 592 struct btrfs_block_rsv *delayed_refs_rsv = &fs_info->delayed_refs_rsv; 593 struct btrfs_block_rsv *trans_rsv = &fs_info->trans_block_rsv; 594 struct btrfs_trans_handle *h; 595 struct btrfs_transaction *cur_trans; 596 u64 num_bytes = 0; 597 u64 qgroup_reserved = 0; 598 u64 delayed_refs_bytes = 0; 599 bool reloc_reserved = false; 600 bool do_chunk_alloc = false; 601 int ret; 602 603 if (BTRFS_FS_ERROR(fs_info)) 604 return ERR_PTR(-EROFS); 605 606 if (current->journal_info) { 607 WARN_ON(type & TRANS_EXTWRITERS); 608 h = current->journal_info; 609 refcount_inc(&h->use_count); 610 WARN_ON(refcount_read(&h->use_count) > 2); 611 h->orig_rsv = h->block_rsv; 612 h->block_rsv = NULL; 613 goto got_it; 614 } 615 616 /* 617 * Do the reservation before we join the transaction so we can do all 618 * the appropriate flushing if need be. 619 */ 620 if (num_items && root != fs_info->chunk_root) { 621 qgroup_reserved = num_items * fs_info->nodesize; 622 /* 623 * Use prealloc for now, as there might be a currently running 624 * transaction that could free this reserved space prematurely 625 * by committing. 626 */ 627 ret = btrfs_qgroup_reserve_meta_prealloc(root, qgroup_reserved, 628 enforce_qgroups, false); 629 if (ret) 630 return ERR_PTR(ret); 631 632 num_bytes = btrfs_calc_insert_metadata_size(fs_info, num_items); 633 /* 634 * If we plan to insert/update/delete "num_items" from a btree, 635 * we will also generate delayed refs for extent buffers in the 636 * respective btree paths, so reserve space for the delayed refs 637 * that will be generated by the caller as it modifies btrees. 638 * Try to reserve them to avoid excessive use of the global 639 * block reserve. 640 */ 641 delayed_refs_bytes = btrfs_calc_delayed_ref_bytes(fs_info, num_items); 642 643 /* 644 * Do the reservation for the relocation root creation 645 */ 646 if (need_reserve_reloc_root(root)) { 647 num_bytes += fs_info->nodesize; 648 reloc_reserved = true; 649 } 650 651 ret = btrfs_reserve_trans_metadata(fs_info, flush, num_bytes, 652 &delayed_refs_bytes); 653 if (ret) 654 goto reserve_fail; 655 656 btrfs_block_rsv_add_bytes(trans_rsv, num_bytes, true); 657 658 if (trans_rsv->space_info->force_alloc) 659 do_chunk_alloc = true; 660 } else if (num_items == 0 && flush == BTRFS_RESERVE_FLUSH_ALL && 661 !btrfs_block_rsv_full(delayed_refs_rsv)) { 662 /* 663 * Some people call with btrfs_start_transaction(root, 0) 664 * because they can be throttled, but have some other mechanism 665 * for reserving space. We still want these guys to refill the 666 * delayed block_rsv so just add 1 items worth of reservation 667 * here. 668 */ 669 ret = btrfs_delayed_refs_rsv_refill(fs_info, flush); 670 if (ret) 671 goto reserve_fail; 672 } 673 again: 674 h = kmem_cache_zalloc(btrfs_trans_handle_cachep, GFP_NOFS); 675 if (!h) { 676 ret = -ENOMEM; 677 goto alloc_fail; 678 } 679 680 /* 681 * If we are JOIN_NOLOCK we're already committing a transaction and 682 * waiting on this guy, so we don't need to do the sb_start_intwrite 683 * because we're already holding a ref. We need this because we could 684 * have raced in and did an fsync() on a file which can kick a commit 685 * and then we deadlock with somebody doing a freeze. 686 * 687 * If we are ATTACH, it means we just want to catch the current 688 * transaction and commit it, so we needn't do sb_start_intwrite(). 689 */ 690 if (type & __TRANS_FREEZABLE) 691 sb_start_intwrite(fs_info->sb); 692 693 if (may_wait_transaction(fs_info, type)) 694 wait_current_trans(fs_info); 695 696 do { 697 ret = join_transaction(fs_info, type); 698 if (ret == -EBUSY) { 699 wait_current_trans(fs_info); 700 if (unlikely(type == TRANS_ATTACH || 701 type == TRANS_JOIN_NOSTART)) 702 ret = -ENOENT; 703 } 704 } while (ret == -EBUSY); 705 706 if (ret < 0) 707 goto join_fail; 708 709 cur_trans = fs_info->running_transaction; 710 711 h->transid = cur_trans->transid; 712 h->transaction = cur_trans; 713 refcount_set(&h->use_count, 1); 714 h->fs_info = root->fs_info; 715 716 h->type = type; 717 INIT_LIST_HEAD(&h->new_bgs); 718 btrfs_init_metadata_block_rsv(fs_info, &h->delayed_rsv, BTRFS_BLOCK_RSV_DELOPS); 719 720 smp_mb(); 721 if (cur_trans->state >= TRANS_STATE_COMMIT_START && 722 may_wait_transaction(fs_info, type)) { 723 current->journal_info = h; 724 btrfs_commit_transaction(h); 725 goto again; 726 } 727 728 if (num_bytes) { 729 trace_btrfs_space_reservation(fs_info, "transaction", 730 h->transid, num_bytes, 1); 731 h->block_rsv = trans_rsv; 732 h->bytes_reserved = num_bytes; 733 if (delayed_refs_bytes > 0) { 734 trace_btrfs_space_reservation(fs_info, 735 "local_delayed_refs_rsv", 736 h->transid, 737 delayed_refs_bytes, 1); 738 h->delayed_refs_bytes_reserved = delayed_refs_bytes; 739 btrfs_block_rsv_add_bytes(&h->delayed_rsv, delayed_refs_bytes, true); 740 delayed_refs_bytes = 0; 741 } 742 h->reloc_reserved = reloc_reserved; 743 } 744 745 got_it: 746 if (!current->journal_info) 747 current->journal_info = h; 748 749 /* 750 * If the space_info is marked ALLOC_FORCE then we'll get upgraded to 751 * ALLOC_FORCE the first run through, and then we won't allocate for 752 * anybody else who races in later. We don't care about the return 753 * value here. 754 */ 755 if (do_chunk_alloc && num_bytes) { 756 u64 flags = h->block_rsv->space_info->flags; 757 758 btrfs_chunk_alloc(h, btrfs_get_alloc_profile(fs_info, flags), 759 CHUNK_ALLOC_NO_FORCE); 760 } 761 762 /* 763 * btrfs_record_root_in_trans() needs to alloc new extents, and may 764 * call btrfs_join_transaction() while we're also starting a 765 * transaction. 766 * 767 * Thus it need to be called after current->journal_info initialized, 768 * or we can deadlock. 769 */ 770 ret = btrfs_record_root_in_trans(h, root); 771 if (ret) { 772 /* 773 * The transaction handle is fully initialized and linked with 774 * other structures so it needs to be ended in case of errors, 775 * not just freed. 776 */ 777 btrfs_end_transaction(h); 778 goto reserve_fail; 779 } 780 /* 781 * Now that we have found a transaction to be a part of, convert the 782 * qgroup reservation from prealloc to pertrans. A different transaction 783 * can't race in and free our pertrans out from under us. 784 */ 785 if (qgroup_reserved) 786 btrfs_qgroup_convert_reserved_meta(root, qgroup_reserved); 787 788 return h; 789 790 join_fail: 791 if (type & __TRANS_FREEZABLE) 792 sb_end_intwrite(fs_info->sb); 793 kmem_cache_free(btrfs_trans_handle_cachep, h); 794 alloc_fail: 795 if (num_bytes) 796 btrfs_block_rsv_release(fs_info, trans_rsv, num_bytes, NULL); 797 if (delayed_refs_bytes) 798 btrfs_space_info_free_bytes_may_use(trans_rsv->space_info, delayed_refs_bytes); 799 reserve_fail: 800 btrfs_qgroup_free_meta_prealloc(root, qgroup_reserved); 801 return ERR_PTR(ret); 802 } 803 804 struct btrfs_trans_handle *btrfs_start_transaction(struct btrfs_root *root, 805 unsigned int num_items) 806 { 807 return start_transaction(root, num_items, TRANS_START, 808 BTRFS_RESERVE_FLUSH_ALL, true); 809 } 810 811 struct btrfs_trans_handle *btrfs_start_transaction_fallback_global_rsv( 812 struct btrfs_root *root, 813 unsigned int num_items) 814 { 815 return start_transaction(root, num_items, TRANS_START, 816 BTRFS_RESERVE_FLUSH_ALL_STEAL, false); 817 } 818 819 struct btrfs_trans_handle *btrfs_join_transaction(struct btrfs_root *root) 820 { 821 return start_transaction(root, 0, TRANS_JOIN, BTRFS_RESERVE_NO_FLUSH, 822 true); 823 } 824 825 struct btrfs_trans_handle *btrfs_join_transaction_spacecache(struct btrfs_root *root) 826 { 827 return start_transaction(root, 0, TRANS_JOIN_NOLOCK, 828 BTRFS_RESERVE_NO_FLUSH, true); 829 } 830 831 /* 832 * Similar to regular join but it never starts a transaction when none is 833 * running or when there's a running one at a state >= TRANS_STATE_UNBLOCKED. 834 * This is similar to btrfs_attach_transaction() but it allows the join to 835 * happen if the transaction commit already started but it's not yet in the 836 * "doing" phase (the state is < TRANS_STATE_COMMIT_DOING). 837 */ 838 struct btrfs_trans_handle *btrfs_join_transaction_nostart(struct btrfs_root *root) 839 { 840 return start_transaction(root, 0, TRANS_JOIN_NOSTART, 841 BTRFS_RESERVE_NO_FLUSH, true); 842 } 843 844 /* 845 * Catch the running transaction. 846 * 847 * It is used when we want to commit the current the transaction, but 848 * don't want to start a new one. 849 * 850 * Note: If this function return -ENOENT, it just means there is no 851 * running transaction. But it is possible that the inactive transaction 852 * is still in the memory, not fully on disk. If you hope there is no 853 * inactive transaction in the fs when -ENOENT is returned, you should 854 * invoke 855 * btrfs_attach_transaction_barrier() 856 */ 857 struct btrfs_trans_handle *btrfs_attach_transaction(struct btrfs_root *root) 858 { 859 return start_transaction(root, 0, TRANS_ATTACH, 860 BTRFS_RESERVE_NO_FLUSH, true); 861 } 862 863 /* 864 * Catch the running transaction. 865 * 866 * It is similar to the above function, the difference is this one 867 * will wait for all the inactive transactions until they fully 868 * complete. 869 */ 870 struct btrfs_trans_handle * 871 btrfs_attach_transaction_barrier(struct btrfs_root *root) 872 { 873 struct btrfs_trans_handle *trans; 874 875 trans = start_transaction(root, 0, TRANS_ATTACH, 876 BTRFS_RESERVE_NO_FLUSH, true); 877 if (trans == ERR_PTR(-ENOENT)) { 878 int ret; 879 880 ret = btrfs_wait_for_commit(root->fs_info, 0); 881 if (ret) 882 return ERR_PTR(ret); 883 } 884 885 return trans; 886 } 887 888 /* Wait for a transaction commit to reach at least the given state. */ 889 static noinline void wait_for_commit(struct btrfs_transaction *commit, 890 const enum btrfs_trans_state min_state) 891 { 892 struct btrfs_fs_info *fs_info = commit->fs_info; 893 u64 transid = commit->transid; 894 bool put = false; 895 896 /* 897 * At the moment this function is called with min_state either being 898 * TRANS_STATE_COMPLETED or TRANS_STATE_SUPER_COMMITTED. 899 */ 900 if (min_state == TRANS_STATE_COMPLETED) 901 btrfs_might_wait_for_state(fs_info, BTRFS_LOCKDEP_TRANS_COMPLETED); 902 else 903 btrfs_might_wait_for_state(fs_info, BTRFS_LOCKDEP_TRANS_SUPER_COMMITTED); 904 905 while (1) { 906 wait_event(commit->commit_wait, commit->state >= min_state); 907 if (put) 908 btrfs_put_transaction(commit); 909 910 if (min_state < TRANS_STATE_COMPLETED) 911 break; 912 913 /* 914 * A transaction isn't really completed until all of the 915 * previous transactions are completed, but with fsync we can 916 * end up with SUPER_COMMITTED transactions before a COMPLETED 917 * transaction. Wait for those. 918 */ 919 920 spin_lock(&fs_info->trans_lock); 921 commit = list_first_entry_or_null(&fs_info->trans_list, 922 struct btrfs_transaction, 923 list); 924 if (!commit || commit->transid > transid) { 925 spin_unlock(&fs_info->trans_lock); 926 break; 927 } 928 refcount_inc(&commit->use_count); 929 put = true; 930 spin_unlock(&fs_info->trans_lock); 931 } 932 } 933 934 int btrfs_wait_for_commit(struct btrfs_fs_info *fs_info, u64 transid) 935 { 936 struct btrfs_transaction *cur_trans = NULL, *t; 937 int ret = 0; 938 939 if (transid) { 940 if (transid <= btrfs_get_last_trans_committed(fs_info)) 941 goto out; 942 943 /* find specified transaction */ 944 spin_lock(&fs_info->trans_lock); 945 list_for_each_entry(t, &fs_info->trans_list, list) { 946 if (t->transid == transid) { 947 cur_trans = t; 948 refcount_inc(&cur_trans->use_count); 949 ret = 0; 950 break; 951 } 952 if (t->transid > transid) { 953 ret = 0; 954 break; 955 } 956 } 957 spin_unlock(&fs_info->trans_lock); 958 959 /* 960 * The specified transaction doesn't exist, or we 961 * raced with btrfs_commit_transaction 962 */ 963 if (!cur_trans) { 964 if (transid > btrfs_get_last_trans_committed(fs_info)) 965 ret = -EINVAL; 966 goto out; 967 } 968 } else { 969 /* find newest transaction that is committing | committed */ 970 spin_lock(&fs_info->trans_lock); 971 list_for_each_entry_reverse(t, &fs_info->trans_list, 972 list) { 973 if (t->state >= TRANS_STATE_COMMIT_START) { 974 if (t->state == TRANS_STATE_COMPLETED) 975 break; 976 cur_trans = t; 977 refcount_inc(&cur_trans->use_count); 978 break; 979 } 980 } 981 spin_unlock(&fs_info->trans_lock); 982 if (!cur_trans) 983 goto out; /* nothing committing|committed */ 984 } 985 986 wait_for_commit(cur_trans, TRANS_STATE_COMPLETED); 987 ret = cur_trans->aborted; 988 btrfs_put_transaction(cur_trans); 989 out: 990 return ret; 991 } 992 993 void btrfs_throttle(struct btrfs_fs_info *fs_info) 994 { 995 wait_current_trans(fs_info); 996 } 997 998 bool btrfs_should_end_transaction(struct btrfs_trans_handle *trans) 999 { 1000 struct btrfs_transaction *cur_trans = trans->transaction; 1001 1002 if (cur_trans->state >= TRANS_STATE_COMMIT_START || 1003 test_bit(BTRFS_DELAYED_REFS_FLUSHING, &cur_trans->delayed_refs.flags)) 1004 return true; 1005 1006 if (btrfs_check_space_for_delayed_refs(trans->fs_info)) 1007 return true; 1008 1009 return !!btrfs_block_rsv_check(&trans->fs_info->global_block_rsv, 50); 1010 } 1011 1012 static void btrfs_trans_release_metadata(struct btrfs_trans_handle *trans) 1013 1014 { 1015 struct btrfs_fs_info *fs_info = trans->fs_info; 1016 1017 if (!trans->block_rsv) { 1018 ASSERT(!trans->bytes_reserved); 1019 ASSERT(!trans->delayed_refs_bytes_reserved); 1020 return; 1021 } 1022 1023 if (!trans->bytes_reserved) { 1024 ASSERT(!trans->delayed_refs_bytes_reserved); 1025 return; 1026 } 1027 1028 ASSERT(trans->block_rsv == &fs_info->trans_block_rsv); 1029 trace_btrfs_space_reservation(fs_info, "transaction", 1030 trans->transid, trans->bytes_reserved, 0); 1031 btrfs_block_rsv_release(fs_info, trans->block_rsv, 1032 trans->bytes_reserved, NULL); 1033 trans->bytes_reserved = 0; 1034 1035 if (!trans->delayed_refs_bytes_reserved) 1036 return; 1037 1038 trace_btrfs_space_reservation(fs_info, "local_delayed_refs_rsv", 1039 trans->transid, 1040 trans->delayed_refs_bytes_reserved, 0); 1041 btrfs_block_rsv_release(fs_info, &trans->delayed_rsv, 1042 trans->delayed_refs_bytes_reserved, NULL); 1043 trans->delayed_refs_bytes_reserved = 0; 1044 } 1045 1046 static int __btrfs_end_transaction(struct btrfs_trans_handle *trans, 1047 int throttle) 1048 { 1049 struct btrfs_fs_info *info = trans->fs_info; 1050 struct btrfs_transaction *cur_trans = trans->transaction; 1051 int ret = 0; 1052 1053 if (refcount_read(&trans->use_count) > 1) { 1054 refcount_dec(&trans->use_count); 1055 trans->block_rsv = trans->orig_rsv; 1056 return 0; 1057 } 1058 1059 btrfs_trans_release_metadata(trans); 1060 trans->block_rsv = NULL; 1061 1062 btrfs_create_pending_block_groups(trans); 1063 1064 btrfs_trans_release_chunk_metadata(trans); 1065 1066 if (trans->type & __TRANS_FREEZABLE) 1067 sb_end_intwrite(info->sb); 1068 1069 WARN_ON(cur_trans != info->running_transaction); 1070 WARN_ON(atomic_read(&cur_trans->num_writers) < 1); 1071 atomic_dec(&cur_trans->num_writers); 1072 extwriter_counter_dec(cur_trans, trans->type); 1073 1074 cond_wake_up(&cur_trans->writer_wait); 1075 1076 btrfs_lockdep_release(info, btrfs_trans_num_extwriters); 1077 btrfs_lockdep_release(info, btrfs_trans_num_writers); 1078 1079 btrfs_put_transaction(cur_trans); 1080 1081 if (current->journal_info == trans) 1082 current->journal_info = NULL; 1083 1084 if (throttle) 1085 btrfs_run_delayed_iputs(info); 1086 1087 if (TRANS_ABORTED(trans) || BTRFS_FS_ERROR(info)) { 1088 wake_up_process(info->transaction_kthread); 1089 if (TRANS_ABORTED(trans)) 1090 ret = trans->aborted; 1091 else 1092 ret = -EROFS; 1093 } 1094 1095 kmem_cache_free(btrfs_trans_handle_cachep, trans); 1096 return ret; 1097 } 1098 1099 int btrfs_end_transaction(struct btrfs_trans_handle *trans) 1100 { 1101 return __btrfs_end_transaction(trans, 0); 1102 } 1103 1104 int btrfs_end_transaction_throttle(struct btrfs_trans_handle *trans) 1105 { 1106 return __btrfs_end_transaction(trans, 1); 1107 } 1108 1109 /* 1110 * when btree blocks are allocated, they have some corresponding bits set for 1111 * them in one of two extent_io trees. This is used to make sure all of 1112 * those extents are sent to disk but does not wait on them 1113 */ 1114 int btrfs_write_marked_extents(struct btrfs_fs_info *fs_info, 1115 struct extent_io_tree *dirty_pages, int mark) 1116 { 1117 int ret = 0; 1118 struct address_space *mapping = fs_info->btree_inode->i_mapping; 1119 struct extent_state *cached_state = NULL; 1120 u64 start = 0; 1121 u64 end; 1122 1123 while (find_first_extent_bit(dirty_pages, start, &start, &end, 1124 mark, &cached_state)) { 1125 bool wait_writeback = false; 1126 1127 ret = convert_extent_bit(dirty_pages, start, end, 1128 EXTENT_NEED_WAIT, 1129 mark, &cached_state); 1130 /* 1131 * convert_extent_bit can return -ENOMEM, which is most of the 1132 * time a temporary error. So when it happens, ignore the error 1133 * and wait for writeback of this range to finish - because we 1134 * failed to set the bit EXTENT_NEED_WAIT for the range, a call 1135 * to __btrfs_wait_marked_extents() would not know that 1136 * writeback for this range started and therefore wouldn't 1137 * wait for it to finish - we don't want to commit a 1138 * superblock that points to btree nodes/leafs for which 1139 * writeback hasn't finished yet (and without errors). 1140 * We cleanup any entries left in the io tree when committing 1141 * the transaction (through extent_io_tree_release()). 1142 */ 1143 if (ret == -ENOMEM) { 1144 ret = 0; 1145 wait_writeback = true; 1146 } 1147 if (!ret) 1148 ret = filemap_fdatawrite_range(mapping, start, end); 1149 if (!ret && wait_writeback) 1150 ret = filemap_fdatawait_range(mapping, start, end); 1151 free_extent_state(cached_state); 1152 if (ret) 1153 break; 1154 cached_state = NULL; 1155 cond_resched(); 1156 start = end + 1; 1157 } 1158 return ret; 1159 } 1160 1161 /* 1162 * when btree blocks are allocated, they have some corresponding bits set for 1163 * them in one of two extent_io trees. This is used to make sure all of 1164 * those extents are on disk for transaction or log commit. We wait 1165 * on all the pages and clear them from the dirty pages state tree 1166 */ 1167 static int __btrfs_wait_marked_extents(struct btrfs_fs_info *fs_info, 1168 struct extent_io_tree *dirty_pages) 1169 { 1170 struct address_space *mapping = fs_info->btree_inode->i_mapping; 1171 struct extent_state *cached_state = NULL; 1172 u64 start = 0; 1173 u64 end; 1174 int ret = 0; 1175 1176 while (find_first_extent_bit(dirty_pages, start, &start, &end, 1177 EXTENT_NEED_WAIT, &cached_state)) { 1178 /* 1179 * Ignore -ENOMEM errors returned by clear_extent_bit(). 1180 * When committing the transaction, we'll remove any entries 1181 * left in the io tree. For a log commit, we don't remove them 1182 * after committing the log because the tree can be accessed 1183 * concurrently - we do it only at transaction commit time when 1184 * it's safe to do it (through extent_io_tree_release()). 1185 */ 1186 ret = clear_extent_bit(dirty_pages, start, end, 1187 EXTENT_NEED_WAIT, &cached_state); 1188 if (ret == -ENOMEM) 1189 ret = 0; 1190 if (!ret) 1191 ret = filemap_fdatawait_range(mapping, start, end); 1192 free_extent_state(cached_state); 1193 if (ret) 1194 break; 1195 cached_state = NULL; 1196 cond_resched(); 1197 start = end + 1; 1198 } 1199 return ret; 1200 } 1201 1202 static int btrfs_wait_extents(struct btrfs_fs_info *fs_info, 1203 struct extent_io_tree *dirty_pages) 1204 { 1205 bool errors = false; 1206 int err; 1207 1208 err = __btrfs_wait_marked_extents(fs_info, dirty_pages); 1209 if (test_and_clear_bit(BTRFS_FS_BTREE_ERR, &fs_info->flags)) 1210 errors = true; 1211 1212 if (errors && !err) 1213 err = -EIO; 1214 return err; 1215 } 1216 1217 int btrfs_wait_tree_log_extents(struct btrfs_root *log_root, int mark) 1218 { 1219 struct btrfs_fs_info *fs_info = log_root->fs_info; 1220 struct extent_io_tree *dirty_pages = &log_root->dirty_log_pages; 1221 bool errors = false; 1222 int err; 1223 1224 ASSERT(btrfs_root_id(log_root) == BTRFS_TREE_LOG_OBJECTID); 1225 1226 err = __btrfs_wait_marked_extents(fs_info, dirty_pages); 1227 if ((mark & EXTENT_DIRTY) && 1228 test_and_clear_bit(BTRFS_FS_LOG1_ERR, &fs_info->flags)) 1229 errors = true; 1230 1231 if ((mark & EXTENT_NEW) && 1232 test_and_clear_bit(BTRFS_FS_LOG2_ERR, &fs_info->flags)) 1233 errors = true; 1234 1235 if (errors && !err) 1236 err = -EIO; 1237 return err; 1238 } 1239 1240 /* 1241 * When btree blocks are allocated the corresponding extents are marked dirty. 1242 * This function ensures such extents are persisted on disk for transaction or 1243 * log commit. 1244 * 1245 * @trans: transaction whose dirty pages we'd like to write 1246 */ 1247 static int btrfs_write_and_wait_transaction(struct btrfs_trans_handle *trans) 1248 { 1249 int ret; 1250 int ret2; 1251 struct extent_io_tree *dirty_pages = &trans->transaction->dirty_pages; 1252 struct btrfs_fs_info *fs_info = trans->fs_info; 1253 struct blk_plug plug; 1254 1255 blk_start_plug(&plug); 1256 ret = btrfs_write_marked_extents(fs_info, dirty_pages, EXTENT_DIRTY); 1257 blk_finish_plug(&plug); 1258 ret2 = btrfs_wait_extents(fs_info, dirty_pages); 1259 1260 extent_io_tree_release(&trans->transaction->dirty_pages); 1261 1262 if (ret) 1263 return ret; 1264 else if (ret2) 1265 return ret2; 1266 else 1267 return 0; 1268 } 1269 1270 /* 1271 * this is used to update the root pointer in the tree of tree roots. 1272 * 1273 * But, in the case of the extent allocation tree, updating the root 1274 * pointer may allocate blocks which may change the root of the extent 1275 * allocation tree. 1276 * 1277 * So, this loops and repeats and makes sure the cowonly root didn't 1278 * change while the root pointer was being updated in the metadata. 1279 */ 1280 static int update_cowonly_root(struct btrfs_trans_handle *trans, 1281 struct btrfs_root *root) 1282 { 1283 int ret; 1284 u64 old_root_bytenr; 1285 u64 old_root_used; 1286 struct btrfs_fs_info *fs_info = root->fs_info; 1287 struct btrfs_root *tree_root = fs_info->tree_root; 1288 1289 old_root_used = btrfs_root_used(&root->root_item); 1290 1291 while (1) { 1292 old_root_bytenr = btrfs_root_bytenr(&root->root_item); 1293 if (old_root_bytenr == root->node->start && 1294 old_root_used == btrfs_root_used(&root->root_item)) 1295 break; 1296 1297 btrfs_set_root_node(&root->root_item, root->node); 1298 ret = btrfs_update_root(trans, tree_root, 1299 &root->root_key, 1300 &root->root_item); 1301 if (ret) 1302 return ret; 1303 1304 old_root_used = btrfs_root_used(&root->root_item); 1305 } 1306 1307 return 0; 1308 } 1309 1310 /* 1311 * update all the cowonly tree roots on disk 1312 * 1313 * The error handling in this function may not be obvious. Any of the 1314 * failures will cause the file system to go offline. We still need 1315 * to clean up the delayed refs. 1316 */ 1317 static noinline int commit_cowonly_roots(struct btrfs_trans_handle *trans) 1318 { 1319 struct btrfs_fs_info *fs_info = trans->fs_info; 1320 struct list_head *dirty_bgs = &trans->transaction->dirty_bgs; 1321 struct list_head *io_bgs = &trans->transaction->io_bgs; 1322 struct list_head *next; 1323 struct extent_buffer *eb; 1324 int ret; 1325 1326 /* 1327 * At this point no one can be using this transaction to modify any tree 1328 * and no one can start another transaction to modify any tree either. 1329 */ 1330 ASSERT(trans->transaction->state == TRANS_STATE_COMMIT_DOING); 1331 1332 eb = btrfs_lock_root_node(fs_info->tree_root); 1333 ret = btrfs_cow_block(trans, fs_info->tree_root, eb, NULL, 1334 0, &eb, BTRFS_NESTING_COW); 1335 btrfs_tree_unlock(eb); 1336 free_extent_buffer(eb); 1337 1338 if (ret) 1339 return ret; 1340 1341 ret = btrfs_run_dev_stats(trans); 1342 if (ret) 1343 return ret; 1344 ret = btrfs_run_dev_replace(trans); 1345 if (ret) 1346 return ret; 1347 ret = btrfs_run_qgroups(trans); 1348 if (ret) 1349 return ret; 1350 1351 ret = btrfs_setup_space_cache(trans); 1352 if (ret) 1353 return ret; 1354 1355 again: 1356 while (!list_empty(&fs_info->dirty_cowonly_roots)) { 1357 struct btrfs_root *root; 1358 next = fs_info->dirty_cowonly_roots.next; 1359 list_del_init(next); 1360 root = list_entry(next, struct btrfs_root, dirty_list); 1361 clear_bit(BTRFS_ROOT_DIRTY, &root->state); 1362 1363 list_add_tail(&root->dirty_list, 1364 &trans->transaction->switch_commits); 1365 ret = update_cowonly_root(trans, root); 1366 if (ret) 1367 return ret; 1368 } 1369 1370 /* Now flush any delayed refs generated by updating all of the roots */ 1371 ret = btrfs_run_delayed_refs(trans, U64_MAX); 1372 if (ret) 1373 return ret; 1374 1375 while (!list_empty(dirty_bgs) || !list_empty(io_bgs)) { 1376 ret = btrfs_write_dirty_block_groups(trans); 1377 if (ret) 1378 return ret; 1379 1380 /* 1381 * We're writing the dirty block groups, which could generate 1382 * delayed refs, which could generate more dirty block groups, 1383 * so we want to keep this flushing in this loop to make sure 1384 * everything gets run. 1385 */ 1386 ret = btrfs_run_delayed_refs(trans, U64_MAX); 1387 if (ret) 1388 return ret; 1389 } 1390 1391 if (!list_empty(&fs_info->dirty_cowonly_roots)) 1392 goto again; 1393 1394 /* Update dev-replace pointer once everything is committed */ 1395 fs_info->dev_replace.committed_cursor_left = 1396 fs_info->dev_replace.cursor_left_last_write_of_item; 1397 1398 return 0; 1399 } 1400 1401 /* 1402 * If we had a pending drop we need to see if there are any others left in our 1403 * dead roots list, and if not clear our bit and wake any waiters. 1404 */ 1405 void btrfs_maybe_wake_unfinished_drop(struct btrfs_fs_info *fs_info) 1406 { 1407 /* 1408 * We put the drop in progress roots at the front of the list, so if the 1409 * first entry doesn't have UNFINISHED_DROP set we can wake everybody 1410 * up. 1411 */ 1412 spin_lock(&fs_info->trans_lock); 1413 if (!list_empty(&fs_info->dead_roots)) { 1414 struct btrfs_root *root = list_first_entry(&fs_info->dead_roots, 1415 struct btrfs_root, 1416 root_list); 1417 if (test_bit(BTRFS_ROOT_UNFINISHED_DROP, &root->state)) { 1418 spin_unlock(&fs_info->trans_lock); 1419 return; 1420 } 1421 } 1422 spin_unlock(&fs_info->trans_lock); 1423 1424 btrfs_wake_unfinished_drop(fs_info); 1425 } 1426 1427 /* 1428 * dead roots are old snapshots that need to be deleted. This allocates 1429 * a dirty root struct and adds it into the list of dead roots that need to 1430 * be deleted 1431 */ 1432 void btrfs_add_dead_root(struct btrfs_root *root) 1433 { 1434 struct btrfs_fs_info *fs_info = root->fs_info; 1435 1436 spin_lock(&fs_info->trans_lock); 1437 if (list_empty(&root->root_list)) { 1438 btrfs_grab_root(root); 1439 1440 /* We want to process the partially complete drops first. */ 1441 if (test_bit(BTRFS_ROOT_UNFINISHED_DROP, &root->state)) 1442 list_add(&root->root_list, &fs_info->dead_roots); 1443 else 1444 list_add_tail(&root->root_list, &fs_info->dead_roots); 1445 } 1446 spin_unlock(&fs_info->trans_lock); 1447 } 1448 1449 /* 1450 * Update each subvolume root and its relocation root, if it exists, in the tree 1451 * of tree roots. Also free log roots if they exist. 1452 */ 1453 static noinline int commit_fs_roots(struct btrfs_trans_handle *trans) 1454 { 1455 struct btrfs_fs_info *fs_info = trans->fs_info; 1456 struct btrfs_root *gang[8]; 1457 int i; 1458 int ret; 1459 1460 /* 1461 * At this point no one can be using this transaction to modify any tree 1462 * and no one can start another transaction to modify any tree either. 1463 */ 1464 ASSERT(trans->transaction->state == TRANS_STATE_COMMIT_DOING); 1465 1466 spin_lock(&fs_info->fs_roots_radix_lock); 1467 while (1) { 1468 ret = radix_tree_gang_lookup_tag(&fs_info->fs_roots_radix, 1469 (void **)gang, 0, 1470 ARRAY_SIZE(gang), 1471 BTRFS_ROOT_TRANS_TAG); 1472 if (ret == 0) 1473 break; 1474 for (i = 0; i < ret; i++) { 1475 struct btrfs_root *root = gang[i]; 1476 int ret2; 1477 1478 /* 1479 * At this point we can neither have tasks logging inodes 1480 * from a root nor trying to commit a log tree. 1481 */ 1482 ASSERT(atomic_read(&root->log_writers) == 0); 1483 ASSERT(atomic_read(&root->log_commit[0]) == 0); 1484 ASSERT(atomic_read(&root->log_commit[1]) == 0); 1485 1486 radix_tree_tag_clear(&fs_info->fs_roots_radix, 1487 (unsigned long)btrfs_root_id(root), 1488 BTRFS_ROOT_TRANS_TAG); 1489 btrfs_qgroup_free_meta_all_pertrans(root); 1490 spin_unlock(&fs_info->fs_roots_radix_lock); 1491 1492 btrfs_free_log(trans, root); 1493 ret2 = btrfs_update_reloc_root(trans, root); 1494 if (ret2) 1495 return ret2; 1496 1497 /* see comments in should_cow_block() */ 1498 clear_bit(BTRFS_ROOT_FORCE_COW, &root->state); 1499 smp_mb__after_atomic(); 1500 1501 if (root->commit_root != root->node) { 1502 list_add_tail(&root->dirty_list, 1503 &trans->transaction->switch_commits); 1504 btrfs_set_root_node(&root->root_item, 1505 root->node); 1506 } 1507 1508 ret2 = btrfs_update_root(trans, fs_info->tree_root, 1509 &root->root_key, 1510 &root->root_item); 1511 if (ret2) 1512 return ret2; 1513 spin_lock(&fs_info->fs_roots_radix_lock); 1514 } 1515 } 1516 spin_unlock(&fs_info->fs_roots_radix_lock); 1517 return 0; 1518 } 1519 1520 /* 1521 * Do all special snapshot related qgroup dirty hack. 1522 * 1523 * Will do all needed qgroup inherit and dirty hack like switch commit 1524 * roots inside one transaction and write all btree into disk, to make 1525 * qgroup works. 1526 */ 1527 static int qgroup_account_snapshot(struct btrfs_trans_handle *trans, 1528 struct btrfs_root *src, 1529 struct btrfs_root *parent, 1530 struct btrfs_qgroup_inherit *inherit, 1531 u64 dst_objectid) 1532 { 1533 struct btrfs_fs_info *fs_info = src->fs_info; 1534 int ret; 1535 1536 /* 1537 * Save some performance in the case that qgroups are not enabled. If 1538 * this check races with the ioctl, rescan will kick in anyway. 1539 */ 1540 if (!btrfs_qgroup_full_accounting(fs_info)) 1541 return 0; 1542 1543 /* 1544 * Ensure dirty @src will be committed. Or, after coming 1545 * commit_fs_roots() and switch_commit_roots(), any dirty but not 1546 * recorded root will never be updated again, causing an outdated root 1547 * item. 1548 */ 1549 ret = record_root_in_trans(trans, src, 1); 1550 if (ret) 1551 return ret; 1552 1553 /* 1554 * btrfs_qgroup_inherit relies on a consistent view of the usage for the 1555 * src root, so we must run the delayed refs here. 1556 * 1557 * However this isn't particularly fool proof, because there's no 1558 * synchronization keeping us from changing the tree after this point 1559 * before we do the qgroup_inherit, or even from making changes while 1560 * we're doing the qgroup_inherit. But that's a problem for the future, 1561 * for now flush the delayed refs to narrow the race window where the 1562 * qgroup counters could end up wrong. 1563 */ 1564 ret = btrfs_run_delayed_refs(trans, U64_MAX); 1565 if (ret) { 1566 btrfs_abort_transaction(trans, ret); 1567 return ret; 1568 } 1569 1570 ret = commit_fs_roots(trans); 1571 if (ret) 1572 goto out; 1573 ret = btrfs_qgroup_account_extents(trans); 1574 if (ret < 0) 1575 goto out; 1576 1577 /* Now qgroup are all updated, we can inherit it to new qgroups */ 1578 ret = btrfs_qgroup_inherit(trans, btrfs_root_id(src), dst_objectid, 1579 btrfs_root_id(parent), inherit); 1580 if (ret < 0) 1581 goto out; 1582 1583 /* 1584 * Now we do a simplified commit transaction, which will: 1585 * 1) commit all subvolume and extent tree 1586 * To ensure all subvolume and extent tree have a valid 1587 * commit_root to accounting later insert_dir_item() 1588 * 2) write all btree blocks onto disk 1589 * This is to make sure later btree modification will be cowed 1590 * Or commit_root can be populated and cause wrong qgroup numbers 1591 * In this simplified commit, we don't really care about other trees 1592 * like chunk and root tree, as they won't affect qgroup. 1593 * And we don't write super to avoid half committed status. 1594 */ 1595 ret = commit_cowonly_roots(trans); 1596 if (ret) 1597 goto out; 1598 switch_commit_roots(trans); 1599 ret = btrfs_write_and_wait_transaction(trans); 1600 if (ret) 1601 btrfs_handle_fs_error(fs_info, ret, 1602 "Error while writing out transaction for qgroup"); 1603 1604 out: 1605 /* 1606 * Force parent root to be updated, as we recorded it before so its 1607 * last_trans == cur_transid. 1608 * Or it won't be committed again onto disk after later 1609 * insert_dir_item() 1610 */ 1611 if (!ret) 1612 ret = record_root_in_trans(trans, parent, 1); 1613 return ret; 1614 } 1615 1616 /* 1617 * new snapshots need to be created at a very specific time in the 1618 * transaction commit. This does the actual creation. 1619 * 1620 * Note: 1621 * If the error which may affect the commitment of the current transaction 1622 * happens, we should return the error number. If the error which just affect 1623 * the creation of the pending snapshots, just return 0. 1624 */ 1625 static noinline int create_pending_snapshot(struct btrfs_trans_handle *trans, 1626 struct btrfs_pending_snapshot *pending) 1627 { 1628 1629 struct btrfs_fs_info *fs_info = trans->fs_info; 1630 struct btrfs_key key; 1631 struct btrfs_root_item *new_root_item; 1632 struct btrfs_root *tree_root = fs_info->tree_root; 1633 struct btrfs_root *root = pending->root; 1634 struct btrfs_root *parent_root; 1635 struct btrfs_block_rsv *rsv; 1636 struct inode *parent_inode = &pending->dir->vfs_inode; 1637 struct btrfs_path *path; 1638 struct btrfs_dir_item *dir_item; 1639 struct extent_buffer *tmp; 1640 struct extent_buffer *old; 1641 struct timespec64 cur_time; 1642 int ret = 0; 1643 u64 to_reserve = 0; 1644 u64 index = 0; 1645 u64 objectid; 1646 u64 root_flags; 1647 unsigned int nofs_flags; 1648 struct fscrypt_name fname; 1649 1650 ASSERT(pending->path); 1651 path = pending->path; 1652 1653 ASSERT(pending->root_item); 1654 new_root_item = pending->root_item; 1655 1656 /* 1657 * We're inside a transaction and must make sure that any potential 1658 * allocations with GFP_KERNEL in fscrypt won't recurse back to 1659 * filesystem. 1660 */ 1661 nofs_flags = memalloc_nofs_save(); 1662 pending->error = fscrypt_setup_filename(parent_inode, 1663 &pending->dentry->d_name, 0, 1664 &fname); 1665 memalloc_nofs_restore(nofs_flags); 1666 if (pending->error) 1667 goto free_pending; 1668 1669 pending->error = btrfs_get_free_objectid(tree_root, &objectid); 1670 if (pending->error) 1671 goto free_fname; 1672 1673 /* 1674 * Make qgroup to skip current new snapshot's qgroupid, as it is 1675 * accounted by later btrfs_qgroup_inherit(). 1676 */ 1677 btrfs_set_skip_qgroup(trans, objectid); 1678 1679 btrfs_reloc_pre_snapshot(pending, &to_reserve); 1680 1681 if (to_reserve > 0) { 1682 pending->error = btrfs_block_rsv_add(fs_info, 1683 &pending->block_rsv, 1684 to_reserve, 1685 BTRFS_RESERVE_NO_FLUSH); 1686 if (pending->error) 1687 goto clear_skip_qgroup; 1688 } 1689 1690 key.objectid = objectid; 1691 key.offset = (u64)-1; 1692 key.type = BTRFS_ROOT_ITEM_KEY; 1693 1694 rsv = trans->block_rsv; 1695 trans->block_rsv = &pending->block_rsv; 1696 trans->bytes_reserved = trans->block_rsv->reserved; 1697 trace_btrfs_space_reservation(fs_info, "transaction", 1698 trans->transid, 1699 trans->bytes_reserved, 1); 1700 parent_root = BTRFS_I(parent_inode)->root; 1701 ret = record_root_in_trans(trans, parent_root, 0); 1702 if (ret) 1703 goto fail; 1704 cur_time = current_time(parent_inode); 1705 1706 /* 1707 * insert the directory item 1708 */ 1709 ret = btrfs_set_inode_index(BTRFS_I(parent_inode), &index); 1710 if (ret) { 1711 btrfs_abort_transaction(trans, ret); 1712 goto fail; 1713 } 1714 1715 /* check if there is a file/dir which has the same name. */ 1716 dir_item = btrfs_lookup_dir_item(NULL, parent_root, path, 1717 btrfs_ino(BTRFS_I(parent_inode)), 1718 &fname.disk_name, 0); 1719 if (dir_item != NULL && !IS_ERR(dir_item)) { 1720 pending->error = -EEXIST; 1721 goto dir_item_existed; 1722 } else if (IS_ERR(dir_item)) { 1723 ret = PTR_ERR(dir_item); 1724 btrfs_abort_transaction(trans, ret); 1725 goto fail; 1726 } 1727 btrfs_release_path(path); 1728 1729 ret = btrfs_create_qgroup(trans, objectid); 1730 if (ret && ret != -EEXIST) { 1731 btrfs_abort_transaction(trans, ret); 1732 goto fail; 1733 } 1734 1735 /* 1736 * pull in the delayed directory update 1737 * and the delayed inode item 1738 * otherwise we corrupt the FS during 1739 * snapshot 1740 */ 1741 ret = btrfs_run_delayed_items(trans); 1742 if (ret) { /* Transaction aborted */ 1743 btrfs_abort_transaction(trans, ret); 1744 goto fail; 1745 } 1746 1747 ret = record_root_in_trans(trans, root, 0); 1748 if (ret) { 1749 btrfs_abort_transaction(trans, ret); 1750 goto fail; 1751 } 1752 btrfs_set_root_last_snapshot(&root->root_item, trans->transid); 1753 memcpy(new_root_item, &root->root_item, sizeof(*new_root_item)); 1754 btrfs_check_and_init_root_item(new_root_item); 1755 1756 root_flags = btrfs_root_flags(new_root_item); 1757 if (pending->readonly) 1758 root_flags |= BTRFS_ROOT_SUBVOL_RDONLY; 1759 else 1760 root_flags &= ~BTRFS_ROOT_SUBVOL_RDONLY; 1761 btrfs_set_root_flags(new_root_item, root_flags); 1762 1763 btrfs_set_root_generation_v2(new_root_item, 1764 trans->transid); 1765 generate_random_guid(new_root_item->uuid); 1766 memcpy(new_root_item->parent_uuid, root->root_item.uuid, 1767 BTRFS_UUID_SIZE); 1768 if (!(root_flags & BTRFS_ROOT_SUBVOL_RDONLY)) { 1769 memset(new_root_item->received_uuid, 0, 1770 sizeof(new_root_item->received_uuid)); 1771 memset(&new_root_item->stime, 0, sizeof(new_root_item->stime)); 1772 memset(&new_root_item->rtime, 0, sizeof(new_root_item->rtime)); 1773 btrfs_set_root_stransid(new_root_item, 0); 1774 btrfs_set_root_rtransid(new_root_item, 0); 1775 } 1776 btrfs_set_stack_timespec_sec(&new_root_item->otime, cur_time.tv_sec); 1777 btrfs_set_stack_timespec_nsec(&new_root_item->otime, cur_time.tv_nsec); 1778 btrfs_set_root_otransid(new_root_item, trans->transid); 1779 1780 old = btrfs_lock_root_node(root); 1781 ret = btrfs_cow_block(trans, root, old, NULL, 0, &old, 1782 BTRFS_NESTING_COW); 1783 if (ret) { 1784 btrfs_tree_unlock(old); 1785 free_extent_buffer(old); 1786 btrfs_abort_transaction(trans, ret); 1787 goto fail; 1788 } 1789 1790 ret = btrfs_copy_root(trans, root, old, &tmp, objectid); 1791 /* clean up in any case */ 1792 btrfs_tree_unlock(old); 1793 free_extent_buffer(old); 1794 if (ret) { 1795 btrfs_abort_transaction(trans, ret); 1796 goto fail; 1797 } 1798 /* see comments in should_cow_block() */ 1799 set_bit(BTRFS_ROOT_FORCE_COW, &root->state); 1800 smp_wmb(); 1801 1802 btrfs_set_root_node(new_root_item, tmp); 1803 /* record when the snapshot was created in key.offset */ 1804 key.offset = trans->transid; 1805 ret = btrfs_insert_root(trans, tree_root, &key, new_root_item); 1806 btrfs_tree_unlock(tmp); 1807 free_extent_buffer(tmp); 1808 if (ret) { 1809 btrfs_abort_transaction(trans, ret); 1810 goto fail; 1811 } 1812 1813 /* 1814 * insert root back/forward references 1815 */ 1816 ret = btrfs_add_root_ref(trans, objectid, 1817 btrfs_root_id(parent_root), 1818 btrfs_ino(BTRFS_I(parent_inode)), index, 1819 &fname.disk_name); 1820 if (ret) { 1821 btrfs_abort_transaction(trans, ret); 1822 goto fail; 1823 } 1824 1825 key.offset = (u64)-1; 1826 pending->snap = btrfs_get_new_fs_root(fs_info, objectid, &pending->anon_dev); 1827 if (IS_ERR(pending->snap)) { 1828 ret = PTR_ERR(pending->snap); 1829 pending->snap = NULL; 1830 btrfs_abort_transaction(trans, ret); 1831 goto fail; 1832 } 1833 1834 ret = btrfs_reloc_post_snapshot(trans, pending); 1835 if (ret) { 1836 btrfs_abort_transaction(trans, ret); 1837 goto fail; 1838 } 1839 1840 /* 1841 * Do special qgroup accounting for snapshot, as we do some qgroup 1842 * snapshot hack to do fast snapshot. 1843 * To co-operate with that hack, we do hack again. 1844 * Or snapshot will be greatly slowed down by a subtree qgroup rescan 1845 */ 1846 if (btrfs_qgroup_mode(fs_info) == BTRFS_QGROUP_MODE_FULL) 1847 ret = qgroup_account_snapshot(trans, root, parent_root, 1848 pending->inherit, objectid); 1849 else if (btrfs_qgroup_mode(fs_info) == BTRFS_QGROUP_MODE_SIMPLE) 1850 ret = btrfs_qgroup_inherit(trans, btrfs_root_id(root), objectid, 1851 btrfs_root_id(parent_root), pending->inherit); 1852 if (ret < 0) 1853 goto fail; 1854 1855 ret = btrfs_insert_dir_item(trans, &fname.disk_name, 1856 BTRFS_I(parent_inode), &key, BTRFS_FT_DIR, 1857 index); 1858 if (ret) { 1859 btrfs_abort_transaction(trans, ret); 1860 goto fail; 1861 } 1862 1863 btrfs_i_size_write(BTRFS_I(parent_inode), parent_inode->i_size + 1864 fname.disk_name.len * 2); 1865 inode_set_mtime_to_ts(parent_inode, 1866 inode_set_ctime_current(parent_inode)); 1867 ret = btrfs_update_inode_fallback(trans, BTRFS_I(parent_inode)); 1868 if (ret) { 1869 btrfs_abort_transaction(trans, ret); 1870 goto fail; 1871 } 1872 ret = btrfs_uuid_tree_add(trans, new_root_item->uuid, 1873 BTRFS_UUID_KEY_SUBVOL, 1874 objectid); 1875 if (ret) { 1876 btrfs_abort_transaction(trans, ret); 1877 goto fail; 1878 } 1879 if (!btrfs_is_empty_uuid(new_root_item->received_uuid)) { 1880 ret = btrfs_uuid_tree_add(trans, new_root_item->received_uuid, 1881 BTRFS_UUID_KEY_RECEIVED_SUBVOL, 1882 objectid); 1883 if (ret && ret != -EEXIST) { 1884 btrfs_abort_transaction(trans, ret); 1885 goto fail; 1886 } 1887 } 1888 1889 fail: 1890 pending->error = ret; 1891 dir_item_existed: 1892 trans->block_rsv = rsv; 1893 trans->bytes_reserved = 0; 1894 clear_skip_qgroup: 1895 btrfs_clear_skip_qgroup(trans); 1896 free_fname: 1897 fscrypt_free_filename(&fname); 1898 free_pending: 1899 kfree(new_root_item); 1900 pending->root_item = NULL; 1901 btrfs_free_path(path); 1902 pending->path = NULL; 1903 1904 return ret; 1905 } 1906 1907 /* 1908 * create all the snapshots we've scheduled for creation 1909 */ 1910 static noinline int create_pending_snapshots(struct btrfs_trans_handle *trans) 1911 { 1912 struct btrfs_pending_snapshot *pending, *next; 1913 struct list_head *head = &trans->transaction->pending_snapshots; 1914 int ret = 0; 1915 1916 list_for_each_entry_safe(pending, next, head, list) { 1917 list_del(&pending->list); 1918 ret = create_pending_snapshot(trans, pending); 1919 if (ret) 1920 break; 1921 } 1922 return ret; 1923 } 1924 1925 static void update_super_roots(struct btrfs_fs_info *fs_info) 1926 { 1927 struct btrfs_root_item *root_item; 1928 struct btrfs_super_block *super; 1929 1930 super = fs_info->super_copy; 1931 1932 root_item = &fs_info->chunk_root->root_item; 1933 super->chunk_root = root_item->bytenr; 1934 super->chunk_root_generation = root_item->generation; 1935 super->chunk_root_level = root_item->level; 1936 1937 root_item = &fs_info->tree_root->root_item; 1938 super->root = root_item->bytenr; 1939 super->generation = root_item->generation; 1940 super->root_level = root_item->level; 1941 if (btrfs_test_opt(fs_info, SPACE_CACHE)) 1942 super->cache_generation = root_item->generation; 1943 else if (test_bit(BTRFS_FS_CLEANUP_SPACE_CACHE_V1, &fs_info->flags)) 1944 super->cache_generation = 0; 1945 if (test_bit(BTRFS_FS_UPDATE_UUID_TREE_GEN, &fs_info->flags)) 1946 super->uuid_tree_generation = root_item->generation; 1947 } 1948 1949 int btrfs_transaction_blocked(struct btrfs_fs_info *info) 1950 { 1951 struct btrfs_transaction *trans; 1952 int ret = 0; 1953 1954 spin_lock(&info->trans_lock); 1955 trans = info->running_transaction; 1956 if (trans) 1957 ret = is_transaction_blocked(trans); 1958 spin_unlock(&info->trans_lock); 1959 return ret; 1960 } 1961 1962 void btrfs_commit_transaction_async(struct btrfs_trans_handle *trans) 1963 { 1964 struct btrfs_fs_info *fs_info = trans->fs_info; 1965 struct btrfs_transaction *cur_trans; 1966 1967 /* Kick the transaction kthread. */ 1968 set_bit(BTRFS_FS_COMMIT_TRANS, &fs_info->flags); 1969 wake_up_process(fs_info->transaction_kthread); 1970 1971 /* take transaction reference */ 1972 cur_trans = trans->transaction; 1973 refcount_inc(&cur_trans->use_count); 1974 1975 btrfs_end_transaction(trans); 1976 1977 /* 1978 * Wait for the current transaction commit to start and block 1979 * subsequent transaction joins 1980 */ 1981 btrfs_might_wait_for_state(fs_info, BTRFS_LOCKDEP_TRANS_COMMIT_PREP); 1982 wait_event(fs_info->transaction_blocked_wait, 1983 cur_trans->state >= TRANS_STATE_COMMIT_START || 1984 TRANS_ABORTED(cur_trans)); 1985 btrfs_put_transaction(cur_trans); 1986 } 1987 1988 /* 1989 * If there is a running transaction commit it or if it's already committing, 1990 * wait for its commit to complete. Does not start and commit a new transaction 1991 * if there isn't any running. 1992 */ 1993 int btrfs_commit_current_transaction(struct btrfs_root *root) 1994 { 1995 struct btrfs_trans_handle *trans; 1996 1997 trans = btrfs_attach_transaction_barrier(root); 1998 if (IS_ERR(trans)) { 1999 int ret = PTR_ERR(trans); 2000 2001 return (ret == -ENOENT) ? 0 : ret; 2002 } 2003 2004 return btrfs_commit_transaction(trans); 2005 } 2006 2007 static void cleanup_transaction(struct btrfs_trans_handle *trans, int err) 2008 { 2009 struct btrfs_fs_info *fs_info = trans->fs_info; 2010 struct btrfs_transaction *cur_trans = trans->transaction; 2011 2012 WARN_ON(refcount_read(&trans->use_count) > 1); 2013 2014 btrfs_abort_transaction(trans, err); 2015 2016 spin_lock(&fs_info->trans_lock); 2017 2018 /* 2019 * If the transaction is removed from the list, it means this 2020 * transaction has been committed successfully, so it is impossible 2021 * to call the cleanup function. 2022 */ 2023 BUG_ON(list_empty(&cur_trans->list)); 2024 2025 if (cur_trans == fs_info->running_transaction) { 2026 cur_trans->state = TRANS_STATE_COMMIT_DOING; 2027 spin_unlock(&fs_info->trans_lock); 2028 2029 /* 2030 * The thread has already released the lockdep map as reader 2031 * already in btrfs_commit_transaction(). 2032 */ 2033 btrfs_might_wait_for_event(fs_info, btrfs_trans_num_writers); 2034 wait_event(cur_trans->writer_wait, 2035 atomic_read(&cur_trans->num_writers) == 1); 2036 2037 spin_lock(&fs_info->trans_lock); 2038 } 2039 2040 /* 2041 * Now that we know no one else is still using the transaction we can 2042 * remove the transaction from the list of transactions. This avoids 2043 * the transaction kthread from cleaning up the transaction while some 2044 * other task is still using it, which could result in a use-after-free 2045 * on things like log trees, as it forces the transaction kthread to 2046 * wait for this transaction to be cleaned up by us. 2047 */ 2048 list_del_init(&cur_trans->list); 2049 2050 spin_unlock(&fs_info->trans_lock); 2051 2052 btrfs_cleanup_one_transaction(trans->transaction); 2053 2054 spin_lock(&fs_info->trans_lock); 2055 if (cur_trans == fs_info->running_transaction) 2056 fs_info->running_transaction = NULL; 2057 spin_unlock(&fs_info->trans_lock); 2058 2059 if (trans->type & __TRANS_FREEZABLE) 2060 sb_end_intwrite(fs_info->sb); 2061 btrfs_put_transaction(cur_trans); 2062 btrfs_put_transaction(cur_trans); 2063 2064 trace_btrfs_transaction_commit(fs_info); 2065 2066 if (current->journal_info == trans) 2067 current->journal_info = NULL; 2068 2069 /* 2070 * If relocation is running, we can't cancel scrub because that will 2071 * result in a deadlock. Before relocating a block group, relocation 2072 * pauses scrub, then starts and commits a transaction before unpausing 2073 * scrub. If the transaction commit is being done by the relocation 2074 * task or triggered by another task and the relocation task is waiting 2075 * for the commit, and we end up here due to an error in the commit 2076 * path, then calling btrfs_scrub_cancel() will deadlock, as we are 2077 * asking for scrub to stop while having it asked to be paused higher 2078 * above in relocation code. 2079 */ 2080 if (!test_bit(BTRFS_FS_RELOC_RUNNING, &fs_info->flags)) 2081 btrfs_scrub_cancel(fs_info); 2082 2083 kmem_cache_free(btrfs_trans_handle_cachep, trans); 2084 } 2085 2086 /* 2087 * Release reserved delayed ref space of all pending block groups of the 2088 * transaction and remove them from the list 2089 */ 2090 static void btrfs_cleanup_pending_block_groups(struct btrfs_trans_handle *trans) 2091 { 2092 struct btrfs_fs_info *fs_info = trans->fs_info; 2093 struct btrfs_block_group *block_group, *tmp; 2094 2095 list_for_each_entry_safe(block_group, tmp, &trans->new_bgs, bg_list) { 2096 btrfs_dec_delayed_refs_rsv_bg_inserts(fs_info); 2097 list_del_init(&block_group->bg_list); 2098 } 2099 } 2100 2101 static inline int btrfs_start_delalloc_flush(struct btrfs_fs_info *fs_info) 2102 { 2103 /* 2104 * We use try_to_writeback_inodes_sb() here because if we used 2105 * btrfs_start_delalloc_roots we would deadlock with fs freeze. 2106 * Currently are holding the fs freeze lock, if we do an async flush 2107 * we'll do btrfs_join_transaction() and deadlock because we need to 2108 * wait for the fs freeze lock. Using the direct flushing we benefit 2109 * from already being in a transaction and our join_transaction doesn't 2110 * have to re-take the fs freeze lock. 2111 * 2112 * Note that try_to_writeback_inodes_sb() will only trigger writeback 2113 * if it can read lock sb->s_umount. It will always be able to lock it, 2114 * except when the filesystem is being unmounted or being frozen, but in 2115 * those cases sync_filesystem() is called, which results in calling 2116 * writeback_inodes_sb() while holding a write lock on sb->s_umount. 2117 * Note that we don't call writeback_inodes_sb() directly, because it 2118 * will emit a warning if sb->s_umount is not locked. 2119 */ 2120 if (btrfs_test_opt(fs_info, FLUSHONCOMMIT)) 2121 try_to_writeback_inodes_sb(fs_info->sb, WB_REASON_SYNC); 2122 return 0; 2123 } 2124 2125 static inline void btrfs_wait_delalloc_flush(struct btrfs_fs_info *fs_info) 2126 { 2127 if (btrfs_test_opt(fs_info, FLUSHONCOMMIT)) 2128 btrfs_wait_ordered_roots(fs_info, U64_MAX, NULL); 2129 } 2130 2131 /* 2132 * Add a pending snapshot associated with the given transaction handle to the 2133 * respective handle. This must be called after the transaction commit started 2134 * and while holding fs_info->trans_lock. 2135 * This serves to guarantee a caller of btrfs_commit_transaction() that it can 2136 * safely free the pending snapshot pointer in case btrfs_commit_transaction() 2137 * returns an error. 2138 */ 2139 static void add_pending_snapshot(struct btrfs_trans_handle *trans) 2140 { 2141 struct btrfs_transaction *cur_trans = trans->transaction; 2142 2143 if (!trans->pending_snapshot) 2144 return; 2145 2146 lockdep_assert_held(&trans->fs_info->trans_lock); 2147 ASSERT(cur_trans->state >= TRANS_STATE_COMMIT_PREP); 2148 2149 list_add(&trans->pending_snapshot->list, &cur_trans->pending_snapshots); 2150 } 2151 2152 static void update_commit_stats(struct btrfs_fs_info *fs_info, ktime_t interval) 2153 { 2154 fs_info->commit_stats.commit_count++; 2155 fs_info->commit_stats.last_commit_dur = interval; 2156 fs_info->commit_stats.max_commit_dur = 2157 max_t(u64, fs_info->commit_stats.max_commit_dur, interval); 2158 fs_info->commit_stats.total_commit_dur += interval; 2159 } 2160 2161 int btrfs_commit_transaction(struct btrfs_trans_handle *trans) 2162 { 2163 struct btrfs_fs_info *fs_info = trans->fs_info; 2164 struct btrfs_transaction *cur_trans = trans->transaction; 2165 struct btrfs_transaction *prev_trans = NULL; 2166 int ret; 2167 ktime_t start_time; 2168 ktime_t interval; 2169 2170 ASSERT(refcount_read(&trans->use_count) == 1); 2171 btrfs_trans_state_lockdep_acquire(fs_info, BTRFS_LOCKDEP_TRANS_COMMIT_PREP); 2172 2173 clear_bit(BTRFS_FS_NEED_TRANS_COMMIT, &fs_info->flags); 2174 2175 /* Stop the commit early if ->aborted is set */ 2176 if (TRANS_ABORTED(cur_trans)) { 2177 ret = cur_trans->aborted; 2178 goto lockdep_trans_commit_start_release; 2179 } 2180 2181 btrfs_trans_release_metadata(trans); 2182 trans->block_rsv = NULL; 2183 2184 /* 2185 * We only want one transaction commit doing the flushing so we do not 2186 * waste a bunch of time on lock contention on the extent root node. 2187 */ 2188 if (!test_and_set_bit(BTRFS_DELAYED_REFS_FLUSHING, 2189 &cur_trans->delayed_refs.flags)) { 2190 /* 2191 * Make a pass through all the delayed refs we have so far. 2192 * Any running threads may add more while we are here. 2193 */ 2194 ret = btrfs_run_delayed_refs(trans, 0); 2195 if (ret) 2196 goto lockdep_trans_commit_start_release; 2197 } 2198 2199 btrfs_create_pending_block_groups(trans); 2200 2201 if (!test_bit(BTRFS_TRANS_DIRTY_BG_RUN, &cur_trans->flags)) { 2202 int run_it = 0; 2203 2204 /* this mutex is also taken before trying to set 2205 * block groups readonly. We need to make sure 2206 * that nobody has set a block group readonly 2207 * after a extents from that block group have been 2208 * allocated for cache files. btrfs_set_block_group_ro 2209 * will wait for the transaction to commit if it 2210 * finds BTRFS_TRANS_DIRTY_BG_RUN set. 2211 * 2212 * The BTRFS_TRANS_DIRTY_BG_RUN flag is also used to make sure 2213 * only one process starts all the block group IO. It wouldn't 2214 * hurt to have more than one go through, but there's no 2215 * real advantage to it either. 2216 */ 2217 mutex_lock(&fs_info->ro_block_group_mutex); 2218 if (!test_and_set_bit(BTRFS_TRANS_DIRTY_BG_RUN, 2219 &cur_trans->flags)) 2220 run_it = 1; 2221 mutex_unlock(&fs_info->ro_block_group_mutex); 2222 2223 if (run_it) { 2224 ret = btrfs_start_dirty_block_groups(trans); 2225 if (ret) 2226 goto lockdep_trans_commit_start_release; 2227 } 2228 } 2229 2230 spin_lock(&fs_info->trans_lock); 2231 if (cur_trans->state >= TRANS_STATE_COMMIT_PREP) { 2232 enum btrfs_trans_state want_state = TRANS_STATE_COMPLETED; 2233 2234 add_pending_snapshot(trans); 2235 2236 spin_unlock(&fs_info->trans_lock); 2237 refcount_inc(&cur_trans->use_count); 2238 2239 if (trans->in_fsync) 2240 want_state = TRANS_STATE_SUPER_COMMITTED; 2241 2242 btrfs_trans_state_lockdep_release(fs_info, 2243 BTRFS_LOCKDEP_TRANS_COMMIT_PREP); 2244 ret = btrfs_end_transaction(trans); 2245 wait_for_commit(cur_trans, want_state); 2246 2247 if (TRANS_ABORTED(cur_trans)) 2248 ret = cur_trans->aborted; 2249 2250 btrfs_put_transaction(cur_trans); 2251 2252 return ret; 2253 } 2254 2255 cur_trans->state = TRANS_STATE_COMMIT_PREP; 2256 wake_up(&fs_info->transaction_blocked_wait); 2257 btrfs_trans_state_lockdep_release(fs_info, BTRFS_LOCKDEP_TRANS_COMMIT_PREP); 2258 2259 if (cur_trans->list.prev != &fs_info->trans_list) { 2260 enum btrfs_trans_state want_state = TRANS_STATE_COMPLETED; 2261 2262 if (trans->in_fsync) 2263 want_state = TRANS_STATE_SUPER_COMMITTED; 2264 2265 prev_trans = list_entry(cur_trans->list.prev, 2266 struct btrfs_transaction, list); 2267 if (prev_trans->state < want_state) { 2268 refcount_inc(&prev_trans->use_count); 2269 spin_unlock(&fs_info->trans_lock); 2270 2271 wait_for_commit(prev_trans, want_state); 2272 2273 ret = READ_ONCE(prev_trans->aborted); 2274 2275 btrfs_put_transaction(prev_trans); 2276 if (ret) 2277 goto lockdep_release; 2278 spin_lock(&fs_info->trans_lock); 2279 } 2280 } else { 2281 /* 2282 * The previous transaction was aborted and was already removed 2283 * from the list of transactions at fs_info->trans_list. So we 2284 * abort to prevent writing a new superblock that reflects a 2285 * corrupt state (pointing to trees with unwritten nodes/leafs). 2286 */ 2287 if (BTRFS_FS_ERROR(fs_info)) { 2288 spin_unlock(&fs_info->trans_lock); 2289 ret = -EROFS; 2290 goto lockdep_release; 2291 } 2292 } 2293 2294 cur_trans->state = TRANS_STATE_COMMIT_START; 2295 wake_up(&fs_info->transaction_blocked_wait); 2296 spin_unlock(&fs_info->trans_lock); 2297 2298 /* 2299 * Get the time spent on the work done by the commit thread and not 2300 * the time spent waiting on a previous commit 2301 */ 2302 start_time = ktime_get_ns(); 2303 2304 extwriter_counter_dec(cur_trans, trans->type); 2305 2306 ret = btrfs_start_delalloc_flush(fs_info); 2307 if (ret) 2308 goto lockdep_release; 2309 2310 ret = btrfs_run_delayed_items(trans); 2311 if (ret) 2312 goto lockdep_release; 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_extwriters); 2320 btrfs_might_wait_for_event(fs_info, btrfs_trans_num_extwriters); 2321 wait_event(cur_trans->writer_wait, 2322 extwriter_counter_read(cur_trans) == 0); 2323 2324 /* some pending stuffs might be added after the previous flush. */ 2325 ret = btrfs_run_delayed_items(trans); 2326 if (ret) { 2327 btrfs_lockdep_release(fs_info, btrfs_trans_num_writers); 2328 goto cleanup_transaction; 2329 } 2330 2331 btrfs_wait_delalloc_flush(fs_info); 2332 2333 /* 2334 * Wait for all ordered extents started by a fast fsync that joined this 2335 * transaction. Otherwise if this transaction commits before the ordered 2336 * extents complete we lose logged data after a power failure. 2337 */ 2338 btrfs_might_wait_for_event(fs_info, btrfs_trans_pending_ordered); 2339 wait_event(cur_trans->pending_wait, 2340 atomic_read(&cur_trans->pending_ordered) == 0); 2341 2342 btrfs_scrub_pause(fs_info); 2343 /* 2344 * Ok now we need to make sure to block out any other joins while we 2345 * commit the transaction. We could have started a join before setting 2346 * COMMIT_DOING so make sure to wait for num_writers to == 1 again. 2347 */ 2348 spin_lock(&fs_info->trans_lock); 2349 add_pending_snapshot(trans); 2350 cur_trans->state = TRANS_STATE_COMMIT_DOING; 2351 spin_unlock(&fs_info->trans_lock); 2352 2353 /* 2354 * The thread has started/joined the transaction thus it holds the 2355 * lockdep map as a reader. It has to release it before acquiring the 2356 * lockdep map as a writer. 2357 */ 2358 btrfs_lockdep_release(fs_info, btrfs_trans_num_writers); 2359 btrfs_might_wait_for_event(fs_info, btrfs_trans_num_writers); 2360 wait_event(cur_trans->writer_wait, 2361 atomic_read(&cur_trans->num_writers) == 1); 2362 2363 /* 2364 * Make lockdep happy by acquiring the state locks after 2365 * btrfs_trans_num_writers is released. If we acquired the state locks 2366 * before releasing the btrfs_trans_num_writers lock then lockdep would 2367 * complain because we did not follow the reverse order unlocking rule. 2368 */ 2369 btrfs_trans_state_lockdep_acquire(fs_info, BTRFS_LOCKDEP_TRANS_COMPLETED); 2370 btrfs_trans_state_lockdep_acquire(fs_info, BTRFS_LOCKDEP_TRANS_SUPER_COMMITTED); 2371 btrfs_trans_state_lockdep_acquire(fs_info, BTRFS_LOCKDEP_TRANS_UNBLOCKED); 2372 2373 /* 2374 * We've started the commit, clear the flag in case we were triggered to 2375 * do an async commit but somebody else started before the transaction 2376 * kthread could do the work. 2377 */ 2378 clear_bit(BTRFS_FS_COMMIT_TRANS, &fs_info->flags); 2379 2380 if (TRANS_ABORTED(cur_trans)) { 2381 ret = cur_trans->aborted; 2382 btrfs_trans_state_lockdep_release(fs_info, BTRFS_LOCKDEP_TRANS_UNBLOCKED); 2383 goto scrub_continue; 2384 } 2385 /* 2386 * the reloc mutex makes sure that we stop 2387 * the balancing code from coming in and moving 2388 * extents around in the middle of the commit 2389 */ 2390 mutex_lock(&fs_info->reloc_mutex); 2391 2392 /* 2393 * We needn't worry about the delayed items because we will 2394 * deal with them in create_pending_snapshot(), which is the 2395 * core function of the snapshot creation. 2396 */ 2397 ret = create_pending_snapshots(trans); 2398 if (ret) 2399 goto unlock_reloc; 2400 2401 /* 2402 * We insert the dir indexes of the snapshots and update the inode 2403 * of the snapshots' parents after the snapshot creation, so there 2404 * are some delayed items which are not dealt with. Now deal with 2405 * them. 2406 * 2407 * We needn't worry that this operation will corrupt the snapshots, 2408 * because all the tree which are snapshoted will be forced to COW 2409 * the nodes and leaves. 2410 */ 2411 ret = btrfs_run_delayed_items(trans); 2412 if (ret) 2413 goto unlock_reloc; 2414 2415 ret = btrfs_run_delayed_refs(trans, U64_MAX); 2416 if (ret) 2417 goto unlock_reloc; 2418 2419 /* 2420 * make sure none of the code above managed to slip in a 2421 * delayed item 2422 */ 2423 btrfs_assert_delayed_root_empty(fs_info); 2424 2425 WARN_ON(cur_trans != trans->transaction); 2426 2427 ret = commit_fs_roots(trans); 2428 if (ret) 2429 goto unlock_reloc; 2430 2431 /* commit_fs_roots gets rid of all the tree log roots, it is now 2432 * safe to free the root of tree log roots 2433 */ 2434 btrfs_free_log_root_tree(trans, fs_info); 2435 2436 /* 2437 * Since fs roots are all committed, we can get a quite accurate 2438 * new_roots. So let's do quota accounting. 2439 */ 2440 ret = btrfs_qgroup_account_extents(trans); 2441 if (ret < 0) 2442 goto unlock_reloc; 2443 2444 ret = commit_cowonly_roots(trans); 2445 if (ret) 2446 goto unlock_reloc; 2447 2448 /* 2449 * The tasks which save the space cache and inode cache may also 2450 * update ->aborted, check it. 2451 */ 2452 if (TRANS_ABORTED(cur_trans)) { 2453 ret = cur_trans->aborted; 2454 goto unlock_reloc; 2455 } 2456 2457 cur_trans = fs_info->running_transaction; 2458 2459 btrfs_set_root_node(&fs_info->tree_root->root_item, 2460 fs_info->tree_root->node); 2461 list_add_tail(&fs_info->tree_root->dirty_list, 2462 &cur_trans->switch_commits); 2463 2464 btrfs_set_root_node(&fs_info->chunk_root->root_item, 2465 fs_info->chunk_root->node); 2466 list_add_tail(&fs_info->chunk_root->dirty_list, 2467 &cur_trans->switch_commits); 2468 2469 if (btrfs_fs_incompat(fs_info, EXTENT_TREE_V2)) { 2470 btrfs_set_root_node(&fs_info->block_group_root->root_item, 2471 fs_info->block_group_root->node); 2472 list_add_tail(&fs_info->block_group_root->dirty_list, 2473 &cur_trans->switch_commits); 2474 } 2475 2476 switch_commit_roots(trans); 2477 2478 ASSERT(list_empty(&cur_trans->dirty_bgs)); 2479 ASSERT(list_empty(&cur_trans->io_bgs)); 2480 update_super_roots(fs_info); 2481 2482 btrfs_set_super_log_root(fs_info->super_copy, 0); 2483 btrfs_set_super_log_root_level(fs_info->super_copy, 0); 2484 memcpy(fs_info->super_for_commit, fs_info->super_copy, 2485 sizeof(*fs_info->super_copy)); 2486 2487 btrfs_commit_device_sizes(cur_trans); 2488 2489 clear_bit(BTRFS_FS_LOG1_ERR, &fs_info->flags); 2490 clear_bit(BTRFS_FS_LOG2_ERR, &fs_info->flags); 2491 2492 btrfs_trans_release_chunk_metadata(trans); 2493 2494 /* 2495 * Before changing the transaction state to TRANS_STATE_UNBLOCKED and 2496 * setting fs_info->running_transaction to NULL, lock tree_log_mutex to 2497 * make sure that before we commit our superblock, no other task can 2498 * start a new transaction and commit a log tree before we commit our 2499 * superblock. Anyone trying to commit a log tree locks this mutex before 2500 * writing its superblock. 2501 */ 2502 mutex_lock(&fs_info->tree_log_mutex); 2503 2504 spin_lock(&fs_info->trans_lock); 2505 cur_trans->state = TRANS_STATE_UNBLOCKED; 2506 fs_info->running_transaction = NULL; 2507 spin_unlock(&fs_info->trans_lock); 2508 mutex_unlock(&fs_info->reloc_mutex); 2509 2510 wake_up(&fs_info->transaction_wait); 2511 btrfs_trans_state_lockdep_release(fs_info, BTRFS_LOCKDEP_TRANS_UNBLOCKED); 2512 2513 /* If we have features changed, wake up the cleaner to update sysfs. */ 2514 if (test_bit(BTRFS_FS_FEATURE_CHANGED, &fs_info->flags) && 2515 fs_info->cleaner_kthread) 2516 wake_up_process(fs_info->cleaner_kthread); 2517 2518 ret = btrfs_write_and_wait_transaction(trans); 2519 if (ret) { 2520 btrfs_handle_fs_error(fs_info, ret, 2521 "Error while writing out transaction"); 2522 mutex_unlock(&fs_info->tree_log_mutex); 2523 goto scrub_continue; 2524 } 2525 2526 ret = write_all_supers(fs_info, 0); 2527 /* 2528 * the super is written, we can safely allow the tree-loggers 2529 * to go about their business 2530 */ 2531 mutex_unlock(&fs_info->tree_log_mutex); 2532 if (ret) 2533 goto scrub_continue; 2534 2535 /* 2536 * We needn't acquire the lock here because there is no other task 2537 * which can change it. 2538 */ 2539 cur_trans->state = TRANS_STATE_SUPER_COMMITTED; 2540 wake_up(&cur_trans->commit_wait); 2541 btrfs_trans_state_lockdep_release(fs_info, BTRFS_LOCKDEP_TRANS_SUPER_COMMITTED); 2542 2543 btrfs_finish_extent_commit(trans); 2544 2545 if (test_bit(BTRFS_TRANS_HAVE_FREE_BGS, &cur_trans->flags)) 2546 btrfs_clear_space_info_full(fs_info); 2547 2548 btrfs_set_last_trans_committed(fs_info, cur_trans->transid); 2549 /* 2550 * We needn't acquire the lock here because there is no other task 2551 * which can change it. 2552 */ 2553 cur_trans->state = TRANS_STATE_COMPLETED; 2554 wake_up(&cur_trans->commit_wait); 2555 btrfs_trans_state_lockdep_release(fs_info, BTRFS_LOCKDEP_TRANS_COMPLETED); 2556 2557 spin_lock(&fs_info->trans_lock); 2558 list_del_init(&cur_trans->list); 2559 spin_unlock(&fs_info->trans_lock); 2560 2561 btrfs_put_transaction(cur_trans); 2562 btrfs_put_transaction(cur_trans); 2563 2564 if (trans->type & __TRANS_FREEZABLE) 2565 sb_end_intwrite(fs_info->sb); 2566 2567 trace_btrfs_transaction_commit(fs_info); 2568 2569 interval = ktime_get_ns() - start_time; 2570 2571 btrfs_scrub_continue(fs_info); 2572 2573 if (current->journal_info == trans) 2574 current->journal_info = NULL; 2575 2576 kmem_cache_free(btrfs_trans_handle_cachep, trans); 2577 2578 update_commit_stats(fs_info, interval); 2579 2580 return ret; 2581 2582 unlock_reloc: 2583 mutex_unlock(&fs_info->reloc_mutex); 2584 btrfs_trans_state_lockdep_release(fs_info, BTRFS_LOCKDEP_TRANS_UNBLOCKED); 2585 scrub_continue: 2586 btrfs_trans_state_lockdep_release(fs_info, BTRFS_LOCKDEP_TRANS_SUPER_COMMITTED); 2587 btrfs_trans_state_lockdep_release(fs_info, BTRFS_LOCKDEP_TRANS_COMPLETED); 2588 btrfs_scrub_continue(fs_info); 2589 cleanup_transaction: 2590 btrfs_trans_release_metadata(trans); 2591 btrfs_cleanup_pending_block_groups(trans); 2592 btrfs_trans_release_chunk_metadata(trans); 2593 trans->block_rsv = NULL; 2594 btrfs_warn(fs_info, "Skipping commit of aborted transaction."); 2595 if (current->journal_info == trans) 2596 current->journal_info = NULL; 2597 cleanup_transaction(trans, ret); 2598 2599 return ret; 2600 2601 lockdep_release: 2602 btrfs_lockdep_release(fs_info, btrfs_trans_num_extwriters); 2603 btrfs_lockdep_release(fs_info, btrfs_trans_num_writers); 2604 goto cleanup_transaction; 2605 2606 lockdep_trans_commit_start_release: 2607 btrfs_trans_state_lockdep_release(fs_info, BTRFS_LOCKDEP_TRANS_COMMIT_PREP); 2608 btrfs_end_transaction(trans); 2609 return ret; 2610 } 2611 2612 /* 2613 * return < 0 if error 2614 * 0 if there are no more dead_roots at the time of call 2615 * 1 there are more to be processed, call me again 2616 * 2617 * The return value indicates there are certainly more snapshots to delete, but 2618 * if there comes a new one during processing, it may return 0. We don't mind, 2619 * because btrfs_commit_super will poke cleaner thread and it will process it a 2620 * few seconds later. 2621 */ 2622 int btrfs_clean_one_deleted_snapshot(struct btrfs_fs_info *fs_info) 2623 { 2624 struct btrfs_root *root; 2625 int ret; 2626 2627 spin_lock(&fs_info->trans_lock); 2628 if (list_empty(&fs_info->dead_roots)) { 2629 spin_unlock(&fs_info->trans_lock); 2630 return 0; 2631 } 2632 root = list_first_entry(&fs_info->dead_roots, 2633 struct btrfs_root, root_list); 2634 list_del_init(&root->root_list); 2635 spin_unlock(&fs_info->trans_lock); 2636 2637 btrfs_debug(fs_info, "cleaner removing %llu", btrfs_root_id(root)); 2638 2639 btrfs_kill_all_delayed_nodes(root); 2640 2641 if (btrfs_header_backref_rev(root->node) < 2642 BTRFS_MIXED_BACKREF_REV) 2643 ret = btrfs_drop_snapshot(root, 0, 0); 2644 else 2645 ret = btrfs_drop_snapshot(root, 1, 0); 2646 2647 btrfs_put_root(root); 2648 return (ret < 0) ? 0 : 1; 2649 } 2650 2651 /* 2652 * We only mark the transaction aborted and then set the file system read-only. 2653 * This will prevent new transactions from starting or trying to join this 2654 * one. 2655 * 2656 * This means that error recovery at the call site is limited to freeing 2657 * any local memory allocations and passing the error code up without 2658 * further cleanup. The transaction should complete as it normally would 2659 * in the call path but will return -EIO. 2660 * 2661 * We'll complete the cleanup in btrfs_end_transaction and 2662 * btrfs_commit_transaction. 2663 */ 2664 void __cold __btrfs_abort_transaction(struct btrfs_trans_handle *trans, 2665 const char *function, 2666 unsigned int line, int error, bool first_hit) 2667 { 2668 struct btrfs_fs_info *fs_info = trans->fs_info; 2669 2670 WRITE_ONCE(trans->aborted, error); 2671 WRITE_ONCE(trans->transaction->aborted, error); 2672 if (first_hit && error == -ENOSPC) 2673 btrfs_dump_space_info_for_trans_abort(fs_info); 2674 /* Wake up anybody who may be waiting on this transaction */ 2675 wake_up(&fs_info->transaction_wait); 2676 wake_up(&fs_info->transaction_blocked_wait); 2677 __btrfs_handle_fs_error(fs_info, function, line, error, NULL); 2678 } 2679 2680 int __init btrfs_transaction_init(void) 2681 { 2682 btrfs_trans_handle_cachep = KMEM_CACHE(btrfs_trans_handle, SLAB_TEMPORARY); 2683 if (!btrfs_trans_handle_cachep) 2684 return -ENOMEM; 2685 return 0; 2686 } 2687 2688 void __cold btrfs_transaction_exit(void) 2689 { 2690 kmem_cache_destroy(btrfs_trans_handle_cachep); 2691 } 2692