1 /* 2 * Copyright (C) 2007 Oracle. All rights reserved. 3 * 4 * This program is free software; you can redistribute it and/or 5 * modify it under the terms of the GNU General Public 6 * License v2 as published by the Free Software Foundation. 7 * 8 * This program is distributed in the hope that it will be useful, 9 * but WITHOUT ANY WARRANTY; without even the implied warranty of 10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 11 * General Public License for more details. 12 * 13 * You should have received a copy of the GNU General Public 14 * License along with this program; if not, write to the 15 * Free Software Foundation, Inc., 59 Temple Place - Suite 330, 16 * Boston, MA 021110-1307, USA. 17 */ 18 19 #include <linux/fs.h> 20 #include <linux/slab.h> 21 #include <linux/sched.h> 22 #include <linux/writeback.h> 23 #include <linux/pagemap.h> 24 #include <linux/blkdev.h> 25 #include <linux/uuid.h> 26 #include "ctree.h" 27 #include "disk-io.h" 28 #include "transaction.h" 29 #include "locking.h" 30 #include "tree-log.h" 31 #include "inode-map.h" 32 #include "volumes.h" 33 #include "dev-replace.h" 34 35 #define BTRFS_ROOT_TRANS_TAG 0 36 37 static unsigned int btrfs_blocked_trans_types[TRANS_STATE_MAX] = { 38 [TRANS_STATE_RUNNING] = 0U, 39 [TRANS_STATE_BLOCKED] = (__TRANS_USERSPACE | 40 __TRANS_START), 41 [TRANS_STATE_COMMIT_START] = (__TRANS_USERSPACE | 42 __TRANS_START | 43 __TRANS_ATTACH), 44 [TRANS_STATE_COMMIT_DOING] = (__TRANS_USERSPACE | 45 __TRANS_START | 46 __TRANS_ATTACH | 47 __TRANS_JOIN), 48 [TRANS_STATE_UNBLOCKED] = (__TRANS_USERSPACE | 49 __TRANS_START | 50 __TRANS_ATTACH | 51 __TRANS_JOIN | 52 __TRANS_JOIN_NOLOCK), 53 [TRANS_STATE_COMPLETED] = (__TRANS_USERSPACE | 54 __TRANS_START | 55 __TRANS_ATTACH | 56 __TRANS_JOIN | 57 __TRANS_JOIN_NOLOCK), 58 }; 59 60 void btrfs_put_transaction(struct btrfs_transaction *transaction) 61 { 62 WARN_ON(atomic_read(&transaction->use_count) == 0); 63 if (atomic_dec_and_test(&transaction->use_count)) { 64 BUG_ON(!list_empty(&transaction->list)); 65 WARN_ON(!RB_EMPTY_ROOT(&transaction->delayed_refs.href_root)); 66 while (!list_empty(&transaction->pending_chunks)) { 67 struct extent_map *em; 68 69 em = list_first_entry(&transaction->pending_chunks, 70 struct extent_map, list); 71 list_del_init(&em->list); 72 free_extent_map(em); 73 } 74 kmem_cache_free(btrfs_transaction_cachep, transaction); 75 } 76 } 77 78 static noinline void switch_commit_roots(struct btrfs_transaction *trans, 79 struct btrfs_fs_info *fs_info) 80 { 81 struct btrfs_root *root, *tmp; 82 83 down_write(&fs_info->commit_root_sem); 84 list_for_each_entry_safe(root, tmp, &trans->switch_commits, 85 dirty_list) { 86 list_del_init(&root->dirty_list); 87 free_extent_buffer(root->commit_root); 88 root->commit_root = btrfs_root_node(root); 89 if (is_fstree(root->objectid)) 90 btrfs_unpin_free_ino(root); 91 } 92 up_write(&fs_info->commit_root_sem); 93 } 94 95 static inline void extwriter_counter_inc(struct btrfs_transaction *trans, 96 unsigned int type) 97 { 98 if (type & TRANS_EXTWRITERS) 99 atomic_inc(&trans->num_extwriters); 100 } 101 102 static inline void extwriter_counter_dec(struct btrfs_transaction *trans, 103 unsigned int type) 104 { 105 if (type & TRANS_EXTWRITERS) 106 atomic_dec(&trans->num_extwriters); 107 } 108 109 static inline void extwriter_counter_init(struct btrfs_transaction *trans, 110 unsigned int type) 111 { 112 atomic_set(&trans->num_extwriters, ((type & TRANS_EXTWRITERS) ? 1 : 0)); 113 } 114 115 static inline int extwriter_counter_read(struct btrfs_transaction *trans) 116 { 117 return atomic_read(&trans->num_extwriters); 118 } 119 120 /* 121 * either allocate a new transaction or hop into the existing one 122 */ 123 static noinline int join_transaction(struct btrfs_root *root, unsigned int type) 124 { 125 struct btrfs_transaction *cur_trans; 126 struct btrfs_fs_info *fs_info = root->fs_info; 127 128 spin_lock(&fs_info->trans_lock); 129 loop: 130 /* The file system has been taken offline. No new transactions. */ 131 if (test_bit(BTRFS_FS_STATE_ERROR, &fs_info->fs_state)) { 132 spin_unlock(&fs_info->trans_lock); 133 return -EROFS; 134 } 135 136 cur_trans = fs_info->running_transaction; 137 if (cur_trans) { 138 if (cur_trans->aborted) { 139 spin_unlock(&fs_info->trans_lock); 140 return cur_trans->aborted; 141 } 142 if (btrfs_blocked_trans_types[cur_trans->state] & type) { 143 spin_unlock(&fs_info->trans_lock); 144 return -EBUSY; 145 } 146 atomic_inc(&cur_trans->use_count); 147 atomic_inc(&cur_trans->num_writers); 148 extwriter_counter_inc(cur_trans, type); 149 spin_unlock(&fs_info->trans_lock); 150 return 0; 151 } 152 spin_unlock(&fs_info->trans_lock); 153 154 /* 155 * If we are ATTACH, we just want to catch the current transaction, 156 * and commit it. If there is no transaction, just return ENOENT. 157 */ 158 if (type == TRANS_ATTACH) 159 return -ENOENT; 160 161 /* 162 * JOIN_NOLOCK only happens during the transaction commit, so 163 * it is impossible that ->running_transaction is NULL 164 */ 165 BUG_ON(type == TRANS_JOIN_NOLOCK); 166 167 cur_trans = kmem_cache_alloc(btrfs_transaction_cachep, GFP_NOFS); 168 if (!cur_trans) 169 return -ENOMEM; 170 171 spin_lock(&fs_info->trans_lock); 172 if (fs_info->running_transaction) { 173 /* 174 * someone started a transaction after we unlocked. Make sure 175 * to redo the checks above 176 */ 177 kmem_cache_free(btrfs_transaction_cachep, cur_trans); 178 goto loop; 179 } else if (test_bit(BTRFS_FS_STATE_ERROR, &fs_info->fs_state)) { 180 spin_unlock(&fs_info->trans_lock); 181 kmem_cache_free(btrfs_transaction_cachep, cur_trans); 182 return -EROFS; 183 } 184 185 atomic_set(&cur_trans->num_writers, 1); 186 extwriter_counter_init(cur_trans, type); 187 init_waitqueue_head(&cur_trans->writer_wait); 188 init_waitqueue_head(&cur_trans->commit_wait); 189 cur_trans->state = TRANS_STATE_RUNNING; 190 /* 191 * One for this trans handle, one so it will live on until we 192 * commit the transaction. 193 */ 194 atomic_set(&cur_trans->use_count, 2); 195 cur_trans->start_time = get_seconds(); 196 197 cur_trans->delayed_refs.href_root = RB_ROOT; 198 atomic_set(&cur_trans->delayed_refs.num_entries, 0); 199 cur_trans->delayed_refs.num_heads_ready = 0; 200 cur_trans->delayed_refs.num_heads = 0; 201 cur_trans->delayed_refs.flushing = 0; 202 cur_trans->delayed_refs.run_delayed_start = 0; 203 204 /* 205 * although the tree mod log is per file system and not per transaction, 206 * the log must never go across transaction boundaries. 207 */ 208 smp_mb(); 209 if (!list_empty(&fs_info->tree_mod_seq_list)) 210 WARN(1, KERN_ERR "BTRFS: tree_mod_seq_list not empty when " 211 "creating a fresh transaction\n"); 212 if (!RB_EMPTY_ROOT(&fs_info->tree_mod_log)) 213 WARN(1, KERN_ERR "BTRFS: tree_mod_log rb tree not empty when " 214 "creating a fresh transaction\n"); 215 atomic64_set(&fs_info->tree_mod_seq, 0); 216 217 spin_lock_init(&cur_trans->delayed_refs.lock); 218 219 INIT_LIST_HEAD(&cur_trans->pending_snapshots); 220 INIT_LIST_HEAD(&cur_trans->ordered_operations); 221 INIT_LIST_HEAD(&cur_trans->pending_chunks); 222 INIT_LIST_HEAD(&cur_trans->switch_commits); 223 list_add_tail(&cur_trans->list, &fs_info->trans_list); 224 extent_io_tree_init(&cur_trans->dirty_pages, 225 fs_info->btree_inode->i_mapping); 226 fs_info->generation++; 227 cur_trans->transid = fs_info->generation; 228 fs_info->running_transaction = cur_trans; 229 cur_trans->aborted = 0; 230 spin_unlock(&fs_info->trans_lock); 231 232 return 0; 233 } 234 235 /* 236 * this does all the record keeping required to make sure that a reference 237 * counted root is properly recorded in a given transaction. This is required 238 * to make sure the old root from before we joined the transaction is deleted 239 * when the transaction commits 240 */ 241 static int record_root_in_trans(struct btrfs_trans_handle *trans, 242 struct btrfs_root *root) 243 { 244 if (root->ref_cows && root->last_trans < trans->transid) { 245 WARN_ON(root == root->fs_info->extent_root); 246 WARN_ON(root->commit_root != root->node); 247 248 /* 249 * see below for in_trans_setup usage rules 250 * we have the reloc mutex held now, so there 251 * is only one writer in this function 252 */ 253 root->in_trans_setup = 1; 254 255 /* make sure readers find in_trans_setup before 256 * they find our root->last_trans update 257 */ 258 smp_wmb(); 259 260 spin_lock(&root->fs_info->fs_roots_radix_lock); 261 if (root->last_trans == trans->transid) { 262 spin_unlock(&root->fs_info->fs_roots_radix_lock); 263 return 0; 264 } 265 radix_tree_tag_set(&root->fs_info->fs_roots_radix, 266 (unsigned long)root->root_key.objectid, 267 BTRFS_ROOT_TRANS_TAG); 268 spin_unlock(&root->fs_info->fs_roots_radix_lock); 269 root->last_trans = trans->transid; 270 271 /* this is pretty tricky. We don't want to 272 * take the relocation lock in btrfs_record_root_in_trans 273 * unless we're really doing the first setup for this root in 274 * this transaction. 275 * 276 * Normally we'd use root->last_trans as a flag to decide 277 * if we want to take the expensive mutex. 278 * 279 * But, we have to set root->last_trans before we 280 * init the relocation root, otherwise, we trip over warnings 281 * in ctree.c. The solution used here is to flag ourselves 282 * with root->in_trans_setup. When this is 1, we're still 283 * fixing up the reloc trees and everyone must wait. 284 * 285 * When this is zero, they can trust root->last_trans and fly 286 * through btrfs_record_root_in_trans without having to take the 287 * lock. smp_wmb() makes sure that all the writes above are 288 * done before we pop in the zero below 289 */ 290 btrfs_init_reloc_root(trans, root); 291 smp_wmb(); 292 root->in_trans_setup = 0; 293 } 294 return 0; 295 } 296 297 298 int btrfs_record_root_in_trans(struct btrfs_trans_handle *trans, 299 struct btrfs_root *root) 300 { 301 if (!root->ref_cows) 302 return 0; 303 304 /* 305 * see record_root_in_trans for comments about in_trans_setup usage 306 * and barriers 307 */ 308 smp_rmb(); 309 if (root->last_trans == trans->transid && 310 !root->in_trans_setup) 311 return 0; 312 313 mutex_lock(&root->fs_info->reloc_mutex); 314 record_root_in_trans(trans, root); 315 mutex_unlock(&root->fs_info->reloc_mutex); 316 317 return 0; 318 } 319 320 static inline int is_transaction_blocked(struct btrfs_transaction *trans) 321 { 322 return (trans->state >= TRANS_STATE_BLOCKED && 323 trans->state < TRANS_STATE_UNBLOCKED && 324 !trans->aborted); 325 } 326 327 /* wait for commit against the current transaction to become unblocked 328 * when this is done, it is safe to start a new transaction, but the current 329 * transaction might not be fully on disk. 330 */ 331 static void wait_current_trans(struct btrfs_root *root) 332 { 333 struct btrfs_transaction *cur_trans; 334 335 spin_lock(&root->fs_info->trans_lock); 336 cur_trans = root->fs_info->running_transaction; 337 if (cur_trans && is_transaction_blocked(cur_trans)) { 338 atomic_inc(&cur_trans->use_count); 339 spin_unlock(&root->fs_info->trans_lock); 340 341 wait_event(root->fs_info->transaction_wait, 342 cur_trans->state >= TRANS_STATE_UNBLOCKED || 343 cur_trans->aborted); 344 btrfs_put_transaction(cur_trans); 345 } else { 346 spin_unlock(&root->fs_info->trans_lock); 347 } 348 } 349 350 static int may_wait_transaction(struct btrfs_root *root, int type) 351 { 352 if (root->fs_info->log_root_recovering) 353 return 0; 354 355 if (type == TRANS_USERSPACE) 356 return 1; 357 358 if (type == TRANS_START && 359 !atomic_read(&root->fs_info->open_ioctl_trans)) 360 return 1; 361 362 return 0; 363 } 364 365 static inline bool need_reserve_reloc_root(struct btrfs_root *root) 366 { 367 if (!root->fs_info->reloc_ctl || 368 !root->ref_cows || 369 root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID || 370 root->reloc_root) 371 return false; 372 373 return true; 374 } 375 376 static struct btrfs_trans_handle * 377 start_transaction(struct btrfs_root *root, u64 num_items, unsigned int type, 378 enum btrfs_reserve_flush_enum flush) 379 { 380 struct btrfs_trans_handle *h; 381 struct btrfs_transaction *cur_trans; 382 u64 num_bytes = 0; 383 u64 qgroup_reserved = 0; 384 bool reloc_reserved = false; 385 int ret; 386 387 if (test_bit(BTRFS_FS_STATE_ERROR, &root->fs_info->fs_state)) 388 return ERR_PTR(-EROFS); 389 390 if (current->journal_info && 391 current->journal_info != (void *)BTRFS_SEND_TRANS_STUB) { 392 WARN_ON(type & TRANS_EXTWRITERS); 393 h = current->journal_info; 394 h->use_count++; 395 WARN_ON(h->use_count > 2); 396 h->orig_rsv = h->block_rsv; 397 h->block_rsv = NULL; 398 goto got_it; 399 } 400 401 /* 402 * Do the reservation before we join the transaction so we can do all 403 * the appropriate flushing if need be. 404 */ 405 if (num_items > 0 && root != root->fs_info->chunk_root) { 406 if (root->fs_info->quota_enabled && 407 is_fstree(root->root_key.objectid)) { 408 qgroup_reserved = num_items * root->leafsize; 409 ret = btrfs_qgroup_reserve(root, qgroup_reserved); 410 if (ret) 411 return ERR_PTR(ret); 412 } 413 414 num_bytes = btrfs_calc_trans_metadata_size(root, num_items); 415 /* 416 * Do the reservation for the relocation root creation 417 */ 418 if (unlikely(need_reserve_reloc_root(root))) { 419 num_bytes += root->nodesize; 420 reloc_reserved = true; 421 } 422 423 ret = btrfs_block_rsv_add(root, 424 &root->fs_info->trans_block_rsv, 425 num_bytes, flush); 426 if (ret) 427 goto reserve_fail; 428 } 429 again: 430 h = kmem_cache_alloc(btrfs_trans_handle_cachep, GFP_NOFS); 431 if (!h) { 432 ret = -ENOMEM; 433 goto alloc_fail; 434 } 435 436 /* 437 * If we are JOIN_NOLOCK we're already committing a transaction and 438 * waiting on this guy, so we don't need to do the sb_start_intwrite 439 * because we're already holding a ref. We need this because we could 440 * have raced in and did an fsync() on a file which can kick a commit 441 * and then we deadlock with somebody doing a freeze. 442 * 443 * If we are ATTACH, it means we just want to catch the current 444 * transaction and commit it, so we needn't do sb_start_intwrite(). 445 */ 446 if (type & __TRANS_FREEZABLE) 447 sb_start_intwrite(root->fs_info->sb); 448 449 if (may_wait_transaction(root, type)) 450 wait_current_trans(root); 451 452 do { 453 ret = join_transaction(root, type); 454 if (ret == -EBUSY) { 455 wait_current_trans(root); 456 if (unlikely(type == TRANS_ATTACH)) 457 ret = -ENOENT; 458 } 459 } while (ret == -EBUSY); 460 461 if (ret < 0) { 462 /* We must get the transaction if we are JOIN_NOLOCK. */ 463 BUG_ON(type == TRANS_JOIN_NOLOCK); 464 goto join_fail; 465 } 466 467 cur_trans = root->fs_info->running_transaction; 468 469 h->transid = cur_trans->transid; 470 h->transaction = cur_trans; 471 h->blocks_used = 0; 472 h->bytes_reserved = 0; 473 h->root = root; 474 h->delayed_ref_updates = 0; 475 h->use_count = 1; 476 h->adding_csums = 0; 477 h->block_rsv = NULL; 478 h->orig_rsv = NULL; 479 h->aborted = 0; 480 h->qgroup_reserved = 0; 481 h->delayed_ref_elem.seq = 0; 482 h->type = type; 483 h->allocating_chunk = false; 484 h->reloc_reserved = false; 485 h->sync = false; 486 INIT_LIST_HEAD(&h->qgroup_ref_list); 487 INIT_LIST_HEAD(&h->new_bgs); 488 489 smp_mb(); 490 if (cur_trans->state >= TRANS_STATE_BLOCKED && 491 may_wait_transaction(root, type)) { 492 btrfs_commit_transaction(h, root); 493 goto again; 494 } 495 496 if (num_bytes) { 497 trace_btrfs_space_reservation(root->fs_info, "transaction", 498 h->transid, num_bytes, 1); 499 h->block_rsv = &root->fs_info->trans_block_rsv; 500 h->bytes_reserved = num_bytes; 501 h->reloc_reserved = reloc_reserved; 502 } 503 h->qgroup_reserved = qgroup_reserved; 504 505 got_it: 506 btrfs_record_root_in_trans(h, root); 507 508 if (!current->journal_info && type != TRANS_USERSPACE) 509 current->journal_info = h; 510 return h; 511 512 join_fail: 513 if (type & __TRANS_FREEZABLE) 514 sb_end_intwrite(root->fs_info->sb); 515 kmem_cache_free(btrfs_trans_handle_cachep, h); 516 alloc_fail: 517 if (num_bytes) 518 btrfs_block_rsv_release(root, &root->fs_info->trans_block_rsv, 519 num_bytes); 520 reserve_fail: 521 if (qgroup_reserved) 522 btrfs_qgroup_free(root, qgroup_reserved); 523 return ERR_PTR(ret); 524 } 525 526 struct btrfs_trans_handle *btrfs_start_transaction(struct btrfs_root *root, 527 int num_items) 528 { 529 return start_transaction(root, num_items, TRANS_START, 530 BTRFS_RESERVE_FLUSH_ALL); 531 } 532 533 struct btrfs_trans_handle *btrfs_start_transaction_lflush( 534 struct btrfs_root *root, int num_items) 535 { 536 return start_transaction(root, num_items, TRANS_START, 537 BTRFS_RESERVE_FLUSH_LIMIT); 538 } 539 540 struct btrfs_trans_handle *btrfs_join_transaction(struct btrfs_root *root) 541 { 542 return start_transaction(root, 0, TRANS_JOIN, 0); 543 } 544 545 struct btrfs_trans_handle *btrfs_join_transaction_nolock(struct btrfs_root *root) 546 { 547 return start_transaction(root, 0, TRANS_JOIN_NOLOCK, 0); 548 } 549 550 struct btrfs_trans_handle *btrfs_start_ioctl_transaction(struct btrfs_root *root) 551 { 552 return start_transaction(root, 0, TRANS_USERSPACE, 0); 553 } 554 555 /* 556 * btrfs_attach_transaction() - catch the running transaction 557 * 558 * It is used when we want to commit the current the transaction, but 559 * don't want to start a new one. 560 * 561 * Note: If this function return -ENOENT, it just means there is no 562 * running transaction. But it is possible that the inactive transaction 563 * is still in the memory, not fully on disk. If you hope there is no 564 * inactive transaction in the fs when -ENOENT is returned, you should 565 * invoke 566 * btrfs_attach_transaction_barrier() 567 */ 568 struct btrfs_trans_handle *btrfs_attach_transaction(struct btrfs_root *root) 569 { 570 return start_transaction(root, 0, TRANS_ATTACH, 0); 571 } 572 573 /* 574 * btrfs_attach_transaction_barrier() - catch the running transaction 575 * 576 * It is similar to the above function, the differentia is this one 577 * will wait for all the inactive transactions until they fully 578 * complete. 579 */ 580 struct btrfs_trans_handle * 581 btrfs_attach_transaction_barrier(struct btrfs_root *root) 582 { 583 struct btrfs_trans_handle *trans; 584 585 trans = start_transaction(root, 0, TRANS_ATTACH, 0); 586 if (IS_ERR(trans) && PTR_ERR(trans) == -ENOENT) 587 btrfs_wait_for_commit(root, 0); 588 589 return trans; 590 } 591 592 /* wait for a transaction commit to be fully complete */ 593 static noinline void wait_for_commit(struct btrfs_root *root, 594 struct btrfs_transaction *commit) 595 { 596 wait_event(commit->commit_wait, commit->state == TRANS_STATE_COMPLETED); 597 } 598 599 int btrfs_wait_for_commit(struct btrfs_root *root, u64 transid) 600 { 601 struct btrfs_transaction *cur_trans = NULL, *t; 602 int ret = 0; 603 604 if (transid) { 605 if (transid <= root->fs_info->last_trans_committed) 606 goto out; 607 608 ret = -EINVAL; 609 /* find specified transaction */ 610 spin_lock(&root->fs_info->trans_lock); 611 list_for_each_entry(t, &root->fs_info->trans_list, list) { 612 if (t->transid == transid) { 613 cur_trans = t; 614 atomic_inc(&cur_trans->use_count); 615 ret = 0; 616 break; 617 } 618 if (t->transid > transid) { 619 ret = 0; 620 break; 621 } 622 } 623 spin_unlock(&root->fs_info->trans_lock); 624 /* The specified transaction doesn't exist */ 625 if (!cur_trans) 626 goto out; 627 } else { 628 /* find newest transaction that is committing | committed */ 629 spin_lock(&root->fs_info->trans_lock); 630 list_for_each_entry_reverse(t, &root->fs_info->trans_list, 631 list) { 632 if (t->state >= TRANS_STATE_COMMIT_START) { 633 if (t->state == TRANS_STATE_COMPLETED) 634 break; 635 cur_trans = t; 636 atomic_inc(&cur_trans->use_count); 637 break; 638 } 639 } 640 spin_unlock(&root->fs_info->trans_lock); 641 if (!cur_trans) 642 goto out; /* nothing committing|committed */ 643 } 644 645 wait_for_commit(root, cur_trans); 646 btrfs_put_transaction(cur_trans); 647 out: 648 return ret; 649 } 650 651 void btrfs_throttle(struct btrfs_root *root) 652 { 653 if (!atomic_read(&root->fs_info->open_ioctl_trans)) 654 wait_current_trans(root); 655 } 656 657 static int should_end_transaction(struct btrfs_trans_handle *trans, 658 struct btrfs_root *root) 659 { 660 if (root->fs_info->global_block_rsv.space_info->full && 661 btrfs_check_space_for_delayed_refs(trans, root)) 662 return 1; 663 664 return !!btrfs_block_rsv_check(root, &root->fs_info->global_block_rsv, 5); 665 } 666 667 int btrfs_should_end_transaction(struct btrfs_trans_handle *trans, 668 struct btrfs_root *root) 669 { 670 struct btrfs_transaction *cur_trans = trans->transaction; 671 int updates; 672 int err; 673 674 smp_mb(); 675 if (cur_trans->state >= TRANS_STATE_BLOCKED || 676 cur_trans->delayed_refs.flushing) 677 return 1; 678 679 updates = trans->delayed_ref_updates; 680 trans->delayed_ref_updates = 0; 681 if (updates) { 682 err = btrfs_run_delayed_refs(trans, root, updates); 683 if (err) /* Error code will also eval true */ 684 return err; 685 } 686 687 return should_end_transaction(trans, root); 688 } 689 690 static int __btrfs_end_transaction(struct btrfs_trans_handle *trans, 691 struct btrfs_root *root, int throttle) 692 { 693 struct btrfs_transaction *cur_trans = trans->transaction; 694 struct btrfs_fs_info *info = root->fs_info; 695 unsigned long cur = trans->delayed_ref_updates; 696 int lock = (trans->type != TRANS_JOIN_NOLOCK); 697 int err = 0; 698 699 if (trans->use_count > 1) { 700 trans->use_count--; 701 trans->block_rsv = trans->orig_rsv; 702 return 0; 703 } 704 705 /* 706 * do the qgroup accounting as early as possible 707 */ 708 err = btrfs_delayed_refs_qgroup_accounting(trans, info); 709 710 btrfs_trans_release_metadata(trans, root); 711 trans->block_rsv = NULL; 712 713 if (trans->qgroup_reserved) { 714 /* 715 * the same root has to be passed here between start_transaction 716 * and end_transaction. Subvolume quota depends on this. 717 */ 718 btrfs_qgroup_free(trans->root, trans->qgroup_reserved); 719 trans->qgroup_reserved = 0; 720 } 721 722 if (!list_empty(&trans->new_bgs)) 723 btrfs_create_pending_block_groups(trans, root); 724 725 trans->delayed_ref_updates = 0; 726 if (!trans->sync && btrfs_should_throttle_delayed_refs(trans, root)) { 727 cur = max_t(unsigned long, cur, 32); 728 trans->delayed_ref_updates = 0; 729 btrfs_run_delayed_refs(trans, root, cur); 730 } 731 732 btrfs_trans_release_metadata(trans, root); 733 trans->block_rsv = NULL; 734 735 if (!list_empty(&trans->new_bgs)) 736 btrfs_create_pending_block_groups(trans, root); 737 738 if (lock && !atomic_read(&root->fs_info->open_ioctl_trans) && 739 should_end_transaction(trans, root) && 740 ACCESS_ONCE(cur_trans->state) == TRANS_STATE_RUNNING) { 741 spin_lock(&info->trans_lock); 742 if (cur_trans->state == TRANS_STATE_RUNNING) 743 cur_trans->state = TRANS_STATE_BLOCKED; 744 spin_unlock(&info->trans_lock); 745 } 746 747 if (lock && ACCESS_ONCE(cur_trans->state) == TRANS_STATE_BLOCKED) { 748 if (throttle) 749 return btrfs_commit_transaction(trans, root); 750 else 751 wake_up_process(info->transaction_kthread); 752 } 753 754 if (trans->type & __TRANS_FREEZABLE) 755 sb_end_intwrite(root->fs_info->sb); 756 757 WARN_ON(cur_trans != info->running_transaction); 758 WARN_ON(atomic_read(&cur_trans->num_writers) < 1); 759 atomic_dec(&cur_trans->num_writers); 760 extwriter_counter_dec(cur_trans, trans->type); 761 762 smp_mb(); 763 if (waitqueue_active(&cur_trans->writer_wait)) 764 wake_up(&cur_trans->writer_wait); 765 btrfs_put_transaction(cur_trans); 766 767 if (current->journal_info == trans) 768 current->journal_info = NULL; 769 770 if (throttle) 771 btrfs_run_delayed_iputs(root); 772 773 if (trans->aborted || 774 test_bit(BTRFS_FS_STATE_ERROR, &root->fs_info->fs_state)) { 775 wake_up_process(info->transaction_kthread); 776 err = -EIO; 777 } 778 assert_qgroups_uptodate(trans); 779 780 kmem_cache_free(btrfs_trans_handle_cachep, trans); 781 return err; 782 } 783 784 int btrfs_end_transaction(struct btrfs_trans_handle *trans, 785 struct btrfs_root *root) 786 { 787 return __btrfs_end_transaction(trans, root, 0); 788 } 789 790 int btrfs_end_transaction_throttle(struct btrfs_trans_handle *trans, 791 struct btrfs_root *root) 792 { 793 return __btrfs_end_transaction(trans, root, 1); 794 } 795 796 /* 797 * when btree blocks are allocated, they have some corresponding bits set for 798 * them in one of two extent_io trees. This is used to make sure all of 799 * those extents are sent to disk but does not wait on them 800 */ 801 int btrfs_write_marked_extents(struct btrfs_root *root, 802 struct extent_io_tree *dirty_pages, int mark) 803 { 804 int err = 0; 805 int werr = 0; 806 struct address_space *mapping = root->fs_info->btree_inode->i_mapping; 807 struct extent_state *cached_state = NULL; 808 u64 start = 0; 809 u64 end; 810 811 while (!find_first_extent_bit(dirty_pages, start, &start, &end, 812 mark, &cached_state)) { 813 convert_extent_bit(dirty_pages, start, end, EXTENT_NEED_WAIT, 814 mark, &cached_state, GFP_NOFS); 815 cached_state = NULL; 816 err = filemap_fdatawrite_range(mapping, start, end); 817 if (err) 818 werr = err; 819 cond_resched(); 820 start = end + 1; 821 } 822 if (err) 823 werr = err; 824 return werr; 825 } 826 827 /* 828 * when btree blocks are allocated, they have some corresponding bits set for 829 * them in one of two extent_io trees. This is used to make sure all of 830 * those extents are on disk for transaction or log commit. We wait 831 * on all the pages and clear them from the dirty pages state tree 832 */ 833 int btrfs_wait_marked_extents(struct btrfs_root *root, 834 struct extent_io_tree *dirty_pages, int mark) 835 { 836 int err = 0; 837 int werr = 0; 838 struct address_space *mapping = root->fs_info->btree_inode->i_mapping; 839 struct extent_state *cached_state = NULL; 840 u64 start = 0; 841 u64 end; 842 843 while (!find_first_extent_bit(dirty_pages, start, &start, &end, 844 EXTENT_NEED_WAIT, &cached_state)) { 845 clear_extent_bit(dirty_pages, start, end, EXTENT_NEED_WAIT, 846 0, 0, &cached_state, GFP_NOFS); 847 err = filemap_fdatawait_range(mapping, start, end); 848 if (err) 849 werr = err; 850 cond_resched(); 851 start = end + 1; 852 } 853 if (err) 854 werr = err; 855 return werr; 856 } 857 858 /* 859 * when btree blocks are allocated, they have some corresponding bits set for 860 * them in one of two extent_io trees. This is used to make sure all of 861 * those extents are on disk for transaction or log commit 862 */ 863 static int btrfs_write_and_wait_marked_extents(struct btrfs_root *root, 864 struct extent_io_tree *dirty_pages, int mark) 865 { 866 int ret; 867 int ret2; 868 struct blk_plug plug; 869 870 blk_start_plug(&plug); 871 ret = btrfs_write_marked_extents(root, dirty_pages, mark); 872 blk_finish_plug(&plug); 873 ret2 = btrfs_wait_marked_extents(root, dirty_pages, mark); 874 875 if (ret) 876 return ret; 877 if (ret2) 878 return ret2; 879 return 0; 880 } 881 882 int btrfs_write_and_wait_transaction(struct btrfs_trans_handle *trans, 883 struct btrfs_root *root) 884 { 885 if (!trans || !trans->transaction) { 886 struct inode *btree_inode; 887 btree_inode = root->fs_info->btree_inode; 888 return filemap_write_and_wait(btree_inode->i_mapping); 889 } 890 return btrfs_write_and_wait_marked_extents(root, 891 &trans->transaction->dirty_pages, 892 EXTENT_DIRTY); 893 } 894 895 /* 896 * this is used to update the root pointer in the tree of tree roots. 897 * 898 * But, in the case of the extent allocation tree, updating the root 899 * pointer may allocate blocks which may change the root of the extent 900 * allocation tree. 901 * 902 * So, this loops and repeats and makes sure the cowonly root didn't 903 * change while the root pointer was being updated in the metadata. 904 */ 905 static int update_cowonly_root(struct btrfs_trans_handle *trans, 906 struct btrfs_root *root) 907 { 908 int ret; 909 u64 old_root_bytenr; 910 u64 old_root_used; 911 struct btrfs_root *tree_root = root->fs_info->tree_root; 912 913 old_root_used = btrfs_root_used(&root->root_item); 914 btrfs_write_dirty_block_groups(trans, root); 915 916 while (1) { 917 old_root_bytenr = btrfs_root_bytenr(&root->root_item); 918 if (old_root_bytenr == root->node->start && 919 old_root_used == btrfs_root_used(&root->root_item)) 920 break; 921 922 btrfs_set_root_node(&root->root_item, root->node); 923 ret = btrfs_update_root(trans, tree_root, 924 &root->root_key, 925 &root->root_item); 926 if (ret) 927 return ret; 928 929 old_root_used = btrfs_root_used(&root->root_item); 930 ret = btrfs_write_dirty_block_groups(trans, root); 931 if (ret) 932 return ret; 933 } 934 935 return 0; 936 } 937 938 /* 939 * update all the cowonly tree roots on disk 940 * 941 * The error handling in this function may not be obvious. Any of the 942 * failures will cause the file system to go offline. We still need 943 * to clean up the delayed refs. 944 */ 945 static noinline int commit_cowonly_roots(struct btrfs_trans_handle *trans, 946 struct btrfs_root *root) 947 { 948 struct btrfs_fs_info *fs_info = root->fs_info; 949 struct list_head *next; 950 struct extent_buffer *eb; 951 int ret; 952 953 ret = btrfs_run_delayed_refs(trans, root, (unsigned long)-1); 954 if (ret) 955 return ret; 956 957 eb = btrfs_lock_root_node(fs_info->tree_root); 958 ret = btrfs_cow_block(trans, fs_info->tree_root, eb, NULL, 959 0, &eb); 960 btrfs_tree_unlock(eb); 961 free_extent_buffer(eb); 962 963 if (ret) 964 return ret; 965 966 ret = btrfs_run_delayed_refs(trans, root, (unsigned long)-1); 967 if (ret) 968 return ret; 969 970 ret = btrfs_run_dev_stats(trans, root->fs_info); 971 if (ret) 972 return ret; 973 ret = btrfs_run_dev_replace(trans, root->fs_info); 974 if (ret) 975 return ret; 976 ret = btrfs_run_qgroups(trans, root->fs_info); 977 if (ret) 978 return ret; 979 980 /* run_qgroups might have added some more refs */ 981 ret = btrfs_run_delayed_refs(trans, root, (unsigned long)-1); 982 if (ret) 983 return ret; 984 985 while (!list_empty(&fs_info->dirty_cowonly_roots)) { 986 next = fs_info->dirty_cowonly_roots.next; 987 list_del_init(next); 988 root = list_entry(next, struct btrfs_root, dirty_list); 989 990 if (root != fs_info->extent_root) 991 list_add_tail(&root->dirty_list, 992 &trans->transaction->switch_commits); 993 ret = update_cowonly_root(trans, root); 994 if (ret) 995 return ret; 996 } 997 998 list_add_tail(&fs_info->extent_root->dirty_list, 999 &trans->transaction->switch_commits); 1000 btrfs_after_dev_replace_commit(fs_info); 1001 1002 return 0; 1003 } 1004 1005 /* 1006 * dead roots are old snapshots that need to be deleted. This allocates 1007 * a dirty root struct and adds it into the list of dead roots that need to 1008 * be deleted 1009 */ 1010 void btrfs_add_dead_root(struct btrfs_root *root) 1011 { 1012 spin_lock(&root->fs_info->trans_lock); 1013 if (list_empty(&root->root_list)) 1014 list_add_tail(&root->root_list, &root->fs_info->dead_roots); 1015 spin_unlock(&root->fs_info->trans_lock); 1016 } 1017 1018 /* 1019 * update all the cowonly tree roots on disk 1020 */ 1021 static noinline int commit_fs_roots(struct btrfs_trans_handle *trans, 1022 struct btrfs_root *root) 1023 { 1024 struct btrfs_root *gang[8]; 1025 struct btrfs_fs_info *fs_info = root->fs_info; 1026 int i; 1027 int ret; 1028 int err = 0; 1029 1030 spin_lock(&fs_info->fs_roots_radix_lock); 1031 while (1) { 1032 ret = radix_tree_gang_lookup_tag(&fs_info->fs_roots_radix, 1033 (void **)gang, 0, 1034 ARRAY_SIZE(gang), 1035 BTRFS_ROOT_TRANS_TAG); 1036 if (ret == 0) 1037 break; 1038 for (i = 0; i < ret; i++) { 1039 root = gang[i]; 1040 radix_tree_tag_clear(&fs_info->fs_roots_radix, 1041 (unsigned long)root->root_key.objectid, 1042 BTRFS_ROOT_TRANS_TAG); 1043 spin_unlock(&fs_info->fs_roots_radix_lock); 1044 1045 btrfs_free_log(trans, root); 1046 btrfs_update_reloc_root(trans, root); 1047 btrfs_orphan_commit_root(trans, root); 1048 1049 btrfs_save_ino_cache(root, trans); 1050 1051 /* see comments in should_cow_block() */ 1052 root->force_cow = 0; 1053 smp_wmb(); 1054 1055 if (root->commit_root != root->node) { 1056 list_add_tail(&root->dirty_list, 1057 &trans->transaction->switch_commits); 1058 btrfs_set_root_node(&root->root_item, 1059 root->node); 1060 } 1061 1062 err = btrfs_update_root(trans, fs_info->tree_root, 1063 &root->root_key, 1064 &root->root_item); 1065 spin_lock(&fs_info->fs_roots_radix_lock); 1066 if (err) 1067 break; 1068 } 1069 } 1070 spin_unlock(&fs_info->fs_roots_radix_lock); 1071 return err; 1072 } 1073 1074 /* 1075 * defrag a given btree. 1076 * Every leaf in the btree is read and defragged. 1077 */ 1078 int btrfs_defrag_root(struct btrfs_root *root) 1079 { 1080 struct btrfs_fs_info *info = root->fs_info; 1081 struct btrfs_trans_handle *trans; 1082 int ret; 1083 1084 if (xchg(&root->defrag_running, 1)) 1085 return 0; 1086 1087 while (1) { 1088 trans = btrfs_start_transaction(root, 0); 1089 if (IS_ERR(trans)) 1090 return PTR_ERR(trans); 1091 1092 ret = btrfs_defrag_leaves(trans, root); 1093 1094 btrfs_end_transaction(trans, root); 1095 btrfs_btree_balance_dirty(info->tree_root); 1096 cond_resched(); 1097 1098 if (btrfs_fs_closing(root->fs_info) || ret != -EAGAIN) 1099 break; 1100 1101 if (btrfs_defrag_cancelled(root->fs_info)) { 1102 pr_debug("BTRFS: defrag_root cancelled\n"); 1103 ret = -EAGAIN; 1104 break; 1105 } 1106 } 1107 root->defrag_running = 0; 1108 return ret; 1109 } 1110 1111 /* 1112 * new snapshots need to be created at a very specific time in the 1113 * transaction commit. This does the actual creation. 1114 * 1115 * Note: 1116 * If the error which may affect the commitment of the current transaction 1117 * happens, we should return the error number. If the error which just affect 1118 * the creation of the pending snapshots, just return 0. 1119 */ 1120 static noinline int create_pending_snapshot(struct btrfs_trans_handle *trans, 1121 struct btrfs_fs_info *fs_info, 1122 struct btrfs_pending_snapshot *pending) 1123 { 1124 struct btrfs_key key; 1125 struct btrfs_root_item *new_root_item; 1126 struct btrfs_root *tree_root = fs_info->tree_root; 1127 struct btrfs_root *root = pending->root; 1128 struct btrfs_root *parent_root; 1129 struct btrfs_block_rsv *rsv; 1130 struct inode *parent_inode; 1131 struct btrfs_path *path; 1132 struct btrfs_dir_item *dir_item; 1133 struct dentry *dentry; 1134 struct extent_buffer *tmp; 1135 struct extent_buffer *old; 1136 struct timespec cur_time = CURRENT_TIME; 1137 int ret = 0; 1138 u64 to_reserve = 0; 1139 u64 index = 0; 1140 u64 objectid; 1141 u64 root_flags; 1142 uuid_le new_uuid; 1143 1144 path = btrfs_alloc_path(); 1145 if (!path) { 1146 pending->error = -ENOMEM; 1147 return 0; 1148 } 1149 1150 new_root_item = kmalloc(sizeof(*new_root_item), GFP_NOFS); 1151 if (!new_root_item) { 1152 pending->error = -ENOMEM; 1153 goto root_item_alloc_fail; 1154 } 1155 1156 pending->error = btrfs_find_free_objectid(tree_root, &objectid); 1157 if (pending->error) 1158 goto no_free_objectid; 1159 1160 btrfs_reloc_pre_snapshot(trans, pending, &to_reserve); 1161 1162 if (to_reserve > 0) { 1163 pending->error = btrfs_block_rsv_add(root, 1164 &pending->block_rsv, 1165 to_reserve, 1166 BTRFS_RESERVE_NO_FLUSH); 1167 if (pending->error) 1168 goto no_free_objectid; 1169 } 1170 1171 pending->error = btrfs_qgroup_inherit(trans, fs_info, 1172 root->root_key.objectid, 1173 objectid, pending->inherit); 1174 if (pending->error) 1175 goto no_free_objectid; 1176 1177 key.objectid = objectid; 1178 key.offset = (u64)-1; 1179 key.type = BTRFS_ROOT_ITEM_KEY; 1180 1181 rsv = trans->block_rsv; 1182 trans->block_rsv = &pending->block_rsv; 1183 trans->bytes_reserved = trans->block_rsv->reserved; 1184 1185 dentry = pending->dentry; 1186 parent_inode = pending->dir; 1187 parent_root = BTRFS_I(parent_inode)->root; 1188 record_root_in_trans(trans, parent_root); 1189 1190 /* 1191 * insert the directory item 1192 */ 1193 ret = btrfs_set_inode_index(parent_inode, &index); 1194 BUG_ON(ret); /* -ENOMEM */ 1195 1196 /* check if there is a file/dir which has the same name. */ 1197 dir_item = btrfs_lookup_dir_item(NULL, parent_root, path, 1198 btrfs_ino(parent_inode), 1199 dentry->d_name.name, 1200 dentry->d_name.len, 0); 1201 if (dir_item != NULL && !IS_ERR(dir_item)) { 1202 pending->error = -EEXIST; 1203 goto dir_item_existed; 1204 } else if (IS_ERR(dir_item)) { 1205 ret = PTR_ERR(dir_item); 1206 btrfs_abort_transaction(trans, root, ret); 1207 goto fail; 1208 } 1209 btrfs_release_path(path); 1210 1211 /* 1212 * pull in the delayed directory update 1213 * and the delayed inode item 1214 * otherwise we corrupt the FS during 1215 * snapshot 1216 */ 1217 ret = btrfs_run_delayed_items(trans, root); 1218 if (ret) { /* Transaction aborted */ 1219 btrfs_abort_transaction(trans, root, ret); 1220 goto fail; 1221 } 1222 1223 record_root_in_trans(trans, root); 1224 btrfs_set_root_last_snapshot(&root->root_item, trans->transid); 1225 memcpy(new_root_item, &root->root_item, sizeof(*new_root_item)); 1226 btrfs_check_and_init_root_item(new_root_item); 1227 1228 root_flags = btrfs_root_flags(new_root_item); 1229 if (pending->readonly) 1230 root_flags |= BTRFS_ROOT_SUBVOL_RDONLY; 1231 else 1232 root_flags &= ~BTRFS_ROOT_SUBVOL_RDONLY; 1233 btrfs_set_root_flags(new_root_item, root_flags); 1234 1235 btrfs_set_root_generation_v2(new_root_item, 1236 trans->transid); 1237 uuid_le_gen(&new_uuid); 1238 memcpy(new_root_item->uuid, new_uuid.b, BTRFS_UUID_SIZE); 1239 memcpy(new_root_item->parent_uuid, root->root_item.uuid, 1240 BTRFS_UUID_SIZE); 1241 if (!(root_flags & BTRFS_ROOT_SUBVOL_RDONLY)) { 1242 memset(new_root_item->received_uuid, 0, 1243 sizeof(new_root_item->received_uuid)); 1244 memset(&new_root_item->stime, 0, sizeof(new_root_item->stime)); 1245 memset(&new_root_item->rtime, 0, sizeof(new_root_item->rtime)); 1246 btrfs_set_root_stransid(new_root_item, 0); 1247 btrfs_set_root_rtransid(new_root_item, 0); 1248 } 1249 btrfs_set_stack_timespec_sec(&new_root_item->otime, cur_time.tv_sec); 1250 btrfs_set_stack_timespec_nsec(&new_root_item->otime, cur_time.tv_nsec); 1251 btrfs_set_root_otransid(new_root_item, trans->transid); 1252 1253 old = btrfs_lock_root_node(root); 1254 ret = btrfs_cow_block(trans, root, old, NULL, 0, &old); 1255 if (ret) { 1256 btrfs_tree_unlock(old); 1257 free_extent_buffer(old); 1258 btrfs_abort_transaction(trans, root, ret); 1259 goto fail; 1260 } 1261 1262 btrfs_set_lock_blocking(old); 1263 1264 ret = btrfs_copy_root(trans, root, old, &tmp, objectid); 1265 /* clean up in any case */ 1266 btrfs_tree_unlock(old); 1267 free_extent_buffer(old); 1268 if (ret) { 1269 btrfs_abort_transaction(trans, root, ret); 1270 goto fail; 1271 } 1272 1273 /* see comments in should_cow_block() */ 1274 root->force_cow = 1; 1275 smp_wmb(); 1276 1277 btrfs_set_root_node(new_root_item, tmp); 1278 /* record when the snapshot was created in key.offset */ 1279 key.offset = trans->transid; 1280 ret = btrfs_insert_root(trans, tree_root, &key, new_root_item); 1281 btrfs_tree_unlock(tmp); 1282 free_extent_buffer(tmp); 1283 if (ret) { 1284 btrfs_abort_transaction(trans, root, ret); 1285 goto fail; 1286 } 1287 1288 /* 1289 * insert root back/forward references 1290 */ 1291 ret = btrfs_add_root_ref(trans, tree_root, objectid, 1292 parent_root->root_key.objectid, 1293 btrfs_ino(parent_inode), index, 1294 dentry->d_name.name, dentry->d_name.len); 1295 if (ret) { 1296 btrfs_abort_transaction(trans, root, ret); 1297 goto fail; 1298 } 1299 1300 key.offset = (u64)-1; 1301 pending->snap = btrfs_read_fs_root_no_name(root->fs_info, &key); 1302 if (IS_ERR(pending->snap)) { 1303 ret = PTR_ERR(pending->snap); 1304 btrfs_abort_transaction(trans, root, ret); 1305 goto fail; 1306 } 1307 1308 ret = btrfs_reloc_post_snapshot(trans, pending); 1309 if (ret) { 1310 btrfs_abort_transaction(trans, root, ret); 1311 goto fail; 1312 } 1313 1314 ret = btrfs_run_delayed_refs(trans, root, (unsigned long)-1); 1315 if (ret) { 1316 btrfs_abort_transaction(trans, root, ret); 1317 goto fail; 1318 } 1319 1320 ret = btrfs_insert_dir_item(trans, parent_root, 1321 dentry->d_name.name, dentry->d_name.len, 1322 parent_inode, &key, 1323 BTRFS_FT_DIR, index); 1324 /* We have check then name at the beginning, so it is impossible. */ 1325 BUG_ON(ret == -EEXIST || ret == -EOVERFLOW); 1326 if (ret) { 1327 btrfs_abort_transaction(trans, root, ret); 1328 goto fail; 1329 } 1330 1331 btrfs_i_size_write(parent_inode, parent_inode->i_size + 1332 dentry->d_name.len * 2); 1333 parent_inode->i_mtime = parent_inode->i_ctime = CURRENT_TIME; 1334 ret = btrfs_update_inode_fallback(trans, parent_root, parent_inode); 1335 if (ret) { 1336 btrfs_abort_transaction(trans, root, ret); 1337 goto fail; 1338 } 1339 ret = btrfs_uuid_tree_add(trans, fs_info->uuid_root, new_uuid.b, 1340 BTRFS_UUID_KEY_SUBVOL, objectid); 1341 if (ret) { 1342 btrfs_abort_transaction(trans, root, ret); 1343 goto fail; 1344 } 1345 if (!btrfs_is_empty_uuid(new_root_item->received_uuid)) { 1346 ret = btrfs_uuid_tree_add(trans, fs_info->uuid_root, 1347 new_root_item->received_uuid, 1348 BTRFS_UUID_KEY_RECEIVED_SUBVOL, 1349 objectid); 1350 if (ret && ret != -EEXIST) { 1351 btrfs_abort_transaction(trans, root, ret); 1352 goto fail; 1353 } 1354 } 1355 fail: 1356 pending->error = ret; 1357 dir_item_existed: 1358 trans->block_rsv = rsv; 1359 trans->bytes_reserved = 0; 1360 no_free_objectid: 1361 kfree(new_root_item); 1362 root_item_alloc_fail: 1363 btrfs_free_path(path); 1364 return ret; 1365 } 1366 1367 /* 1368 * create all the snapshots we've scheduled for creation 1369 */ 1370 static noinline int create_pending_snapshots(struct btrfs_trans_handle *trans, 1371 struct btrfs_fs_info *fs_info) 1372 { 1373 struct btrfs_pending_snapshot *pending, *next; 1374 struct list_head *head = &trans->transaction->pending_snapshots; 1375 int ret = 0; 1376 1377 list_for_each_entry_safe(pending, next, head, list) { 1378 list_del(&pending->list); 1379 ret = create_pending_snapshot(trans, fs_info, pending); 1380 if (ret) 1381 break; 1382 } 1383 return ret; 1384 } 1385 1386 static void update_super_roots(struct btrfs_root *root) 1387 { 1388 struct btrfs_root_item *root_item; 1389 struct btrfs_super_block *super; 1390 1391 super = root->fs_info->super_copy; 1392 1393 root_item = &root->fs_info->chunk_root->root_item; 1394 super->chunk_root = root_item->bytenr; 1395 super->chunk_root_generation = root_item->generation; 1396 super->chunk_root_level = root_item->level; 1397 1398 root_item = &root->fs_info->tree_root->root_item; 1399 super->root = root_item->bytenr; 1400 super->generation = root_item->generation; 1401 super->root_level = root_item->level; 1402 if (btrfs_test_opt(root, SPACE_CACHE)) 1403 super->cache_generation = root_item->generation; 1404 if (root->fs_info->update_uuid_tree_gen) 1405 super->uuid_tree_generation = root_item->generation; 1406 } 1407 1408 int btrfs_transaction_in_commit(struct btrfs_fs_info *info) 1409 { 1410 struct btrfs_transaction *trans; 1411 int ret = 0; 1412 1413 spin_lock(&info->trans_lock); 1414 trans = info->running_transaction; 1415 if (trans) 1416 ret = (trans->state >= TRANS_STATE_COMMIT_START); 1417 spin_unlock(&info->trans_lock); 1418 return ret; 1419 } 1420 1421 int btrfs_transaction_blocked(struct btrfs_fs_info *info) 1422 { 1423 struct btrfs_transaction *trans; 1424 int ret = 0; 1425 1426 spin_lock(&info->trans_lock); 1427 trans = info->running_transaction; 1428 if (trans) 1429 ret = is_transaction_blocked(trans); 1430 spin_unlock(&info->trans_lock); 1431 return ret; 1432 } 1433 1434 /* 1435 * wait for the current transaction commit to start and block subsequent 1436 * transaction joins 1437 */ 1438 static void wait_current_trans_commit_start(struct btrfs_root *root, 1439 struct btrfs_transaction *trans) 1440 { 1441 wait_event(root->fs_info->transaction_blocked_wait, 1442 trans->state >= TRANS_STATE_COMMIT_START || 1443 trans->aborted); 1444 } 1445 1446 /* 1447 * wait for the current transaction to start and then become unblocked. 1448 * caller holds ref. 1449 */ 1450 static void wait_current_trans_commit_start_and_unblock(struct btrfs_root *root, 1451 struct btrfs_transaction *trans) 1452 { 1453 wait_event(root->fs_info->transaction_wait, 1454 trans->state >= TRANS_STATE_UNBLOCKED || 1455 trans->aborted); 1456 } 1457 1458 /* 1459 * commit transactions asynchronously. once btrfs_commit_transaction_async 1460 * returns, any subsequent transaction will not be allowed to join. 1461 */ 1462 struct btrfs_async_commit { 1463 struct btrfs_trans_handle *newtrans; 1464 struct btrfs_root *root; 1465 struct work_struct work; 1466 }; 1467 1468 static void do_async_commit(struct work_struct *work) 1469 { 1470 struct btrfs_async_commit *ac = 1471 container_of(work, struct btrfs_async_commit, work); 1472 1473 /* 1474 * We've got freeze protection passed with the transaction. 1475 * Tell lockdep about it. 1476 */ 1477 if (ac->newtrans->type & __TRANS_FREEZABLE) 1478 rwsem_acquire_read( 1479 &ac->root->fs_info->sb->s_writers.lock_map[SB_FREEZE_FS-1], 1480 0, 1, _THIS_IP_); 1481 1482 current->journal_info = ac->newtrans; 1483 1484 btrfs_commit_transaction(ac->newtrans, ac->root); 1485 kfree(ac); 1486 } 1487 1488 int btrfs_commit_transaction_async(struct btrfs_trans_handle *trans, 1489 struct btrfs_root *root, 1490 int wait_for_unblock) 1491 { 1492 struct btrfs_async_commit *ac; 1493 struct btrfs_transaction *cur_trans; 1494 1495 ac = kmalloc(sizeof(*ac), GFP_NOFS); 1496 if (!ac) 1497 return -ENOMEM; 1498 1499 INIT_WORK(&ac->work, do_async_commit); 1500 ac->root = root; 1501 ac->newtrans = btrfs_join_transaction(root); 1502 if (IS_ERR(ac->newtrans)) { 1503 int err = PTR_ERR(ac->newtrans); 1504 kfree(ac); 1505 return err; 1506 } 1507 1508 /* take transaction reference */ 1509 cur_trans = trans->transaction; 1510 atomic_inc(&cur_trans->use_count); 1511 1512 btrfs_end_transaction(trans, root); 1513 1514 /* 1515 * Tell lockdep we've released the freeze rwsem, since the 1516 * async commit thread will be the one to unlock it. 1517 */ 1518 if (ac->newtrans->type & __TRANS_FREEZABLE) 1519 rwsem_release( 1520 &root->fs_info->sb->s_writers.lock_map[SB_FREEZE_FS-1], 1521 1, _THIS_IP_); 1522 1523 schedule_work(&ac->work); 1524 1525 /* wait for transaction to start and unblock */ 1526 if (wait_for_unblock) 1527 wait_current_trans_commit_start_and_unblock(root, cur_trans); 1528 else 1529 wait_current_trans_commit_start(root, cur_trans); 1530 1531 if (current->journal_info == trans) 1532 current->journal_info = NULL; 1533 1534 btrfs_put_transaction(cur_trans); 1535 return 0; 1536 } 1537 1538 1539 static void cleanup_transaction(struct btrfs_trans_handle *trans, 1540 struct btrfs_root *root, int err) 1541 { 1542 struct btrfs_transaction *cur_trans = trans->transaction; 1543 DEFINE_WAIT(wait); 1544 1545 WARN_ON(trans->use_count > 1); 1546 1547 btrfs_abort_transaction(trans, root, err); 1548 1549 spin_lock(&root->fs_info->trans_lock); 1550 1551 /* 1552 * If the transaction is removed from the list, it means this 1553 * transaction has been committed successfully, so it is impossible 1554 * to call the cleanup function. 1555 */ 1556 BUG_ON(list_empty(&cur_trans->list)); 1557 1558 list_del_init(&cur_trans->list); 1559 if (cur_trans == root->fs_info->running_transaction) { 1560 cur_trans->state = TRANS_STATE_COMMIT_DOING; 1561 spin_unlock(&root->fs_info->trans_lock); 1562 wait_event(cur_trans->writer_wait, 1563 atomic_read(&cur_trans->num_writers) == 1); 1564 1565 spin_lock(&root->fs_info->trans_lock); 1566 } 1567 spin_unlock(&root->fs_info->trans_lock); 1568 1569 btrfs_cleanup_one_transaction(trans->transaction, root); 1570 1571 spin_lock(&root->fs_info->trans_lock); 1572 if (cur_trans == root->fs_info->running_transaction) 1573 root->fs_info->running_transaction = NULL; 1574 spin_unlock(&root->fs_info->trans_lock); 1575 1576 if (trans->type & __TRANS_FREEZABLE) 1577 sb_end_intwrite(root->fs_info->sb); 1578 btrfs_put_transaction(cur_trans); 1579 btrfs_put_transaction(cur_trans); 1580 1581 trace_btrfs_transaction_commit(root); 1582 1583 if (current->journal_info == trans) 1584 current->journal_info = NULL; 1585 btrfs_scrub_cancel(root->fs_info); 1586 1587 kmem_cache_free(btrfs_trans_handle_cachep, trans); 1588 } 1589 1590 static int btrfs_flush_all_pending_stuffs(struct btrfs_trans_handle *trans, 1591 struct btrfs_root *root) 1592 { 1593 int ret; 1594 1595 ret = btrfs_run_delayed_items(trans, root); 1596 /* 1597 * running the delayed items may have added new refs. account 1598 * them now so that they hinder processing of more delayed refs 1599 * as little as possible. 1600 */ 1601 if (ret) { 1602 btrfs_delayed_refs_qgroup_accounting(trans, root->fs_info); 1603 return ret; 1604 } 1605 1606 ret = btrfs_delayed_refs_qgroup_accounting(trans, root->fs_info); 1607 if (ret) 1608 return ret; 1609 1610 /* 1611 * rename don't use btrfs_join_transaction, so, once we 1612 * set the transaction to blocked above, we aren't going 1613 * to get any new ordered operations. We can safely run 1614 * it here and no for sure that nothing new will be added 1615 * to the list 1616 */ 1617 ret = btrfs_run_ordered_operations(trans, root, 1); 1618 1619 return ret; 1620 } 1621 1622 static inline int btrfs_start_delalloc_flush(struct btrfs_fs_info *fs_info) 1623 { 1624 if (btrfs_test_opt(fs_info->tree_root, FLUSHONCOMMIT)) 1625 return btrfs_start_delalloc_roots(fs_info, 1, -1); 1626 return 0; 1627 } 1628 1629 static inline void btrfs_wait_delalloc_flush(struct btrfs_fs_info *fs_info) 1630 { 1631 if (btrfs_test_opt(fs_info->tree_root, FLUSHONCOMMIT)) 1632 btrfs_wait_ordered_roots(fs_info, -1); 1633 } 1634 1635 int btrfs_commit_transaction(struct btrfs_trans_handle *trans, 1636 struct btrfs_root *root) 1637 { 1638 struct btrfs_transaction *cur_trans = trans->transaction; 1639 struct btrfs_transaction *prev_trans = NULL; 1640 int ret; 1641 1642 ret = btrfs_run_ordered_operations(trans, root, 0); 1643 if (ret) { 1644 btrfs_abort_transaction(trans, root, ret); 1645 btrfs_end_transaction(trans, root); 1646 return ret; 1647 } 1648 1649 /* Stop the commit early if ->aborted is set */ 1650 if (unlikely(ACCESS_ONCE(cur_trans->aborted))) { 1651 ret = cur_trans->aborted; 1652 btrfs_end_transaction(trans, root); 1653 return ret; 1654 } 1655 1656 /* make a pass through all the delayed refs we have so far 1657 * any runnings procs may add more while we are here 1658 */ 1659 ret = btrfs_run_delayed_refs(trans, root, 0); 1660 if (ret) { 1661 btrfs_end_transaction(trans, root); 1662 return ret; 1663 } 1664 1665 btrfs_trans_release_metadata(trans, root); 1666 trans->block_rsv = NULL; 1667 if (trans->qgroup_reserved) { 1668 btrfs_qgroup_free(root, trans->qgroup_reserved); 1669 trans->qgroup_reserved = 0; 1670 } 1671 1672 cur_trans = trans->transaction; 1673 1674 /* 1675 * set the flushing flag so procs in this transaction have to 1676 * start sending their work down. 1677 */ 1678 cur_trans->delayed_refs.flushing = 1; 1679 smp_wmb(); 1680 1681 if (!list_empty(&trans->new_bgs)) 1682 btrfs_create_pending_block_groups(trans, root); 1683 1684 ret = btrfs_run_delayed_refs(trans, root, 0); 1685 if (ret) { 1686 btrfs_end_transaction(trans, root); 1687 return ret; 1688 } 1689 1690 spin_lock(&root->fs_info->trans_lock); 1691 if (cur_trans->state >= TRANS_STATE_COMMIT_START) { 1692 spin_unlock(&root->fs_info->trans_lock); 1693 atomic_inc(&cur_trans->use_count); 1694 ret = btrfs_end_transaction(trans, root); 1695 1696 wait_for_commit(root, cur_trans); 1697 1698 btrfs_put_transaction(cur_trans); 1699 1700 return ret; 1701 } 1702 1703 cur_trans->state = TRANS_STATE_COMMIT_START; 1704 wake_up(&root->fs_info->transaction_blocked_wait); 1705 1706 if (cur_trans->list.prev != &root->fs_info->trans_list) { 1707 prev_trans = list_entry(cur_trans->list.prev, 1708 struct btrfs_transaction, list); 1709 if (prev_trans->state != TRANS_STATE_COMPLETED) { 1710 atomic_inc(&prev_trans->use_count); 1711 spin_unlock(&root->fs_info->trans_lock); 1712 1713 wait_for_commit(root, prev_trans); 1714 1715 btrfs_put_transaction(prev_trans); 1716 } else { 1717 spin_unlock(&root->fs_info->trans_lock); 1718 } 1719 } else { 1720 spin_unlock(&root->fs_info->trans_lock); 1721 } 1722 1723 extwriter_counter_dec(cur_trans, trans->type); 1724 1725 ret = btrfs_start_delalloc_flush(root->fs_info); 1726 if (ret) 1727 goto cleanup_transaction; 1728 1729 ret = btrfs_flush_all_pending_stuffs(trans, root); 1730 if (ret) 1731 goto cleanup_transaction; 1732 1733 wait_event(cur_trans->writer_wait, 1734 extwriter_counter_read(cur_trans) == 0); 1735 1736 /* some pending stuffs might be added after the previous flush. */ 1737 ret = btrfs_flush_all_pending_stuffs(trans, root); 1738 if (ret) 1739 goto cleanup_transaction; 1740 1741 btrfs_wait_delalloc_flush(root->fs_info); 1742 1743 btrfs_scrub_pause(root); 1744 /* 1745 * Ok now we need to make sure to block out any other joins while we 1746 * commit the transaction. We could have started a join before setting 1747 * COMMIT_DOING so make sure to wait for num_writers to == 1 again. 1748 */ 1749 spin_lock(&root->fs_info->trans_lock); 1750 cur_trans->state = TRANS_STATE_COMMIT_DOING; 1751 spin_unlock(&root->fs_info->trans_lock); 1752 wait_event(cur_trans->writer_wait, 1753 atomic_read(&cur_trans->num_writers) == 1); 1754 1755 /* ->aborted might be set after the previous check, so check it */ 1756 if (unlikely(ACCESS_ONCE(cur_trans->aborted))) { 1757 ret = cur_trans->aborted; 1758 goto scrub_continue; 1759 } 1760 /* 1761 * the reloc mutex makes sure that we stop 1762 * the balancing code from coming in and moving 1763 * extents around in the middle of the commit 1764 */ 1765 mutex_lock(&root->fs_info->reloc_mutex); 1766 1767 /* 1768 * We needn't worry about the delayed items because we will 1769 * deal with them in create_pending_snapshot(), which is the 1770 * core function of the snapshot creation. 1771 */ 1772 ret = create_pending_snapshots(trans, root->fs_info); 1773 if (ret) { 1774 mutex_unlock(&root->fs_info->reloc_mutex); 1775 goto scrub_continue; 1776 } 1777 1778 /* 1779 * We insert the dir indexes of the snapshots and update the inode 1780 * of the snapshots' parents after the snapshot creation, so there 1781 * are some delayed items which are not dealt with. Now deal with 1782 * them. 1783 * 1784 * We needn't worry that this operation will corrupt the snapshots, 1785 * because all the tree which are snapshoted will be forced to COW 1786 * the nodes and leaves. 1787 */ 1788 ret = btrfs_run_delayed_items(trans, root); 1789 if (ret) { 1790 mutex_unlock(&root->fs_info->reloc_mutex); 1791 goto scrub_continue; 1792 } 1793 1794 ret = btrfs_run_delayed_refs(trans, root, (unsigned long)-1); 1795 if (ret) { 1796 mutex_unlock(&root->fs_info->reloc_mutex); 1797 goto scrub_continue; 1798 } 1799 1800 /* 1801 * make sure none of the code above managed to slip in a 1802 * delayed item 1803 */ 1804 btrfs_assert_delayed_root_empty(root); 1805 1806 WARN_ON(cur_trans != trans->transaction); 1807 1808 /* btrfs_commit_tree_roots is responsible for getting the 1809 * various roots consistent with each other. Every pointer 1810 * in the tree of tree roots has to point to the most up to date 1811 * root for every subvolume and other tree. So, we have to keep 1812 * the tree logging code from jumping in and changing any 1813 * of the trees. 1814 * 1815 * At this point in the commit, there can't be any tree-log 1816 * writers, but a little lower down we drop the trans mutex 1817 * and let new people in. By holding the tree_log_mutex 1818 * from now until after the super is written, we avoid races 1819 * with the tree-log code. 1820 */ 1821 mutex_lock(&root->fs_info->tree_log_mutex); 1822 1823 ret = commit_fs_roots(trans, root); 1824 if (ret) { 1825 mutex_unlock(&root->fs_info->tree_log_mutex); 1826 mutex_unlock(&root->fs_info->reloc_mutex); 1827 goto scrub_continue; 1828 } 1829 1830 /* 1831 * Since the transaction is done, we should set the inode map cache flag 1832 * before any other comming transaction. 1833 */ 1834 if (btrfs_test_opt(root, CHANGE_INODE_CACHE)) 1835 btrfs_set_opt(root->fs_info->mount_opt, INODE_MAP_CACHE); 1836 else 1837 btrfs_clear_opt(root->fs_info->mount_opt, INODE_MAP_CACHE); 1838 1839 /* commit_fs_roots gets rid of all the tree log roots, it is now 1840 * safe to free the root of tree log roots 1841 */ 1842 btrfs_free_log_root_tree(trans, root->fs_info); 1843 1844 ret = commit_cowonly_roots(trans, root); 1845 if (ret) { 1846 mutex_unlock(&root->fs_info->tree_log_mutex); 1847 mutex_unlock(&root->fs_info->reloc_mutex); 1848 goto scrub_continue; 1849 } 1850 1851 /* 1852 * The tasks which save the space cache and inode cache may also 1853 * update ->aborted, check it. 1854 */ 1855 if (unlikely(ACCESS_ONCE(cur_trans->aborted))) { 1856 ret = cur_trans->aborted; 1857 mutex_unlock(&root->fs_info->tree_log_mutex); 1858 mutex_unlock(&root->fs_info->reloc_mutex); 1859 goto scrub_continue; 1860 } 1861 1862 btrfs_prepare_extent_commit(trans, root); 1863 1864 cur_trans = root->fs_info->running_transaction; 1865 1866 btrfs_set_root_node(&root->fs_info->tree_root->root_item, 1867 root->fs_info->tree_root->node); 1868 list_add_tail(&root->fs_info->tree_root->dirty_list, 1869 &cur_trans->switch_commits); 1870 1871 btrfs_set_root_node(&root->fs_info->chunk_root->root_item, 1872 root->fs_info->chunk_root->node); 1873 list_add_tail(&root->fs_info->chunk_root->dirty_list, 1874 &cur_trans->switch_commits); 1875 1876 switch_commit_roots(cur_trans, root->fs_info); 1877 1878 assert_qgroups_uptodate(trans); 1879 update_super_roots(root); 1880 1881 btrfs_set_super_log_root(root->fs_info->super_copy, 0); 1882 btrfs_set_super_log_root_level(root->fs_info->super_copy, 0); 1883 memcpy(root->fs_info->super_for_commit, root->fs_info->super_copy, 1884 sizeof(*root->fs_info->super_copy)); 1885 1886 spin_lock(&root->fs_info->trans_lock); 1887 cur_trans->state = TRANS_STATE_UNBLOCKED; 1888 root->fs_info->running_transaction = NULL; 1889 spin_unlock(&root->fs_info->trans_lock); 1890 mutex_unlock(&root->fs_info->reloc_mutex); 1891 1892 wake_up(&root->fs_info->transaction_wait); 1893 1894 ret = btrfs_write_and_wait_transaction(trans, root); 1895 if (ret) { 1896 btrfs_error(root->fs_info, ret, 1897 "Error while writing out transaction"); 1898 mutex_unlock(&root->fs_info->tree_log_mutex); 1899 goto scrub_continue; 1900 } 1901 1902 ret = write_ctree_super(trans, root, 0); 1903 if (ret) { 1904 mutex_unlock(&root->fs_info->tree_log_mutex); 1905 goto scrub_continue; 1906 } 1907 1908 /* 1909 * the super is written, we can safely allow the tree-loggers 1910 * to go about their business 1911 */ 1912 mutex_unlock(&root->fs_info->tree_log_mutex); 1913 1914 btrfs_finish_extent_commit(trans, root); 1915 1916 root->fs_info->last_trans_committed = cur_trans->transid; 1917 /* 1918 * We needn't acquire the lock here because there is no other task 1919 * which can change it. 1920 */ 1921 cur_trans->state = TRANS_STATE_COMPLETED; 1922 wake_up(&cur_trans->commit_wait); 1923 1924 spin_lock(&root->fs_info->trans_lock); 1925 list_del_init(&cur_trans->list); 1926 spin_unlock(&root->fs_info->trans_lock); 1927 1928 btrfs_put_transaction(cur_trans); 1929 btrfs_put_transaction(cur_trans); 1930 1931 if (trans->type & __TRANS_FREEZABLE) 1932 sb_end_intwrite(root->fs_info->sb); 1933 1934 trace_btrfs_transaction_commit(root); 1935 1936 btrfs_scrub_continue(root); 1937 1938 if (current->journal_info == trans) 1939 current->journal_info = NULL; 1940 1941 kmem_cache_free(btrfs_trans_handle_cachep, trans); 1942 1943 if (current != root->fs_info->transaction_kthread) 1944 btrfs_run_delayed_iputs(root); 1945 1946 return ret; 1947 1948 scrub_continue: 1949 btrfs_scrub_continue(root); 1950 cleanup_transaction: 1951 btrfs_trans_release_metadata(trans, root); 1952 trans->block_rsv = NULL; 1953 if (trans->qgroup_reserved) { 1954 btrfs_qgroup_free(root, trans->qgroup_reserved); 1955 trans->qgroup_reserved = 0; 1956 } 1957 btrfs_warn(root->fs_info, "Skipping commit of aborted transaction."); 1958 if (current->journal_info == trans) 1959 current->journal_info = NULL; 1960 cleanup_transaction(trans, root, ret); 1961 1962 return ret; 1963 } 1964 1965 /* 1966 * return < 0 if error 1967 * 0 if there are no more dead_roots at the time of call 1968 * 1 there are more to be processed, call me again 1969 * 1970 * The return value indicates there are certainly more snapshots to delete, but 1971 * if there comes a new one during processing, it may return 0. We don't mind, 1972 * because btrfs_commit_super will poke cleaner thread and it will process it a 1973 * few seconds later. 1974 */ 1975 int btrfs_clean_one_deleted_snapshot(struct btrfs_root *root) 1976 { 1977 int ret; 1978 struct btrfs_fs_info *fs_info = root->fs_info; 1979 1980 spin_lock(&fs_info->trans_lock); 1981 if (list_empty(&fs_info->dead_roots)) { 1982 spin_unlock(&fs_info->trans_lock); 1983 return 0; 1984 } 1985 root = list_first_entry(&fs_info->dead_roots, 1986 struct btrfs_root, root_list); 1987 /* 1988 * Make sure root is not involved in send, 1989 * if we fail with first root, we return 1990 * directly rather than continue. 1991 */ 1992 spin_lock(&root->root_item_lock); 1993 if (root->send_in_progress) { 1994 spin_unlock(&fs_info->trans_lock); 1995 spin_unlock(&root->root_item_lock); 1996 return 0; 1997 } 1998 spin_unlock(&root->root_item_lock); 1999 2000 list_del_init(&root->root_list); 2001 spin_unlock(&fs_info->trans_lock); 2002 2003 pr_debug("BTRFS: cleaner removing %llu\n", root->objectid); 2004 2005 btrfs_kill_all_delayed_nodes(root); 2006 2007 if (btrfs_header_backref_rev(root->node) < 2008 BTRFS_MIXED_BACKREF_REV) 2009 ret = btrfs_drop_snapshot(root, NULL, 0, 0); 2010 else 2011 ret = btrfs_drop_snapshot(root, NULL, 1, 0); 2012 /* 2013 * If we encounter a transaction abort during snapshot cleaning, we 2014 * don't want to crash here 2015 */ 2016 return (ret < 0) ? 0 : 1; 2017 } 2018