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#include "qgroup.h" 35 36#define BTRFS_ROOT_TRANS_TAG 0 37 38static const unsigned int btrfs_blocked_trans_types[TRANS_STATE_MAX] = { 39 [TRANS_STATE_RUNNING] = 0U, 40 [TRANS_STATE_BLOCKED] = (__TRANS_USERSPACE | 41 __TRANS_START), 42 [TRANS_STATE_COMMIT_START] = (__TRANS_USERSPACE | 43 __TRANS_START | 44 __TRANS_ATTACH), 45 [TRANS_STATE_COMMIT_DOING] = (__TRANS_USERSPACE | 46 __TRANS_START | 47 __TRANS_ATTACH | 48 __TRANS_JOIN), 49 [TRANS_STATE_UNBLOCKED] = (__TRANS_USERSPACE | 50 __TRANS_START | 51 __TRANS_ATTACH | 52 __TRANS_JOIN | 53 __TRANS_JOIN_NOLOCK), 54 [TRANS_STATE_COMPLETED] = (__TRANS_USERSPACE | 55 __TRANS_START | 56 __TRANS_ATTACH | 57 __TRANS_JOIN | 58 __TRANS_JOIN_NOLOCK), 59}; 60 61void btrfs_put_transaction(struct btrfs_transaction *transaction) 62{ 63 WARN_ON(atomic_read(&transaction->use_count) == 0); 64 if (atomic_dec_and_test(&transaction->use_count)) { 65 BUG_ON(!list_empty(&transaction->list)); 66 WARN_ON(!RB_EMPTY_ROOT(&transaction->delayed_refs.href_root)); 67 if (transaction->delayed_refs.pending_csums) 68 printk(KERN_ERR "pending csums is %llu\n", 69 transaction->delayed_refs.pending_csums); 70 while (!list_empty(&transaction->pending_chunks)) { 71 struct extent_map *em; 72 73 em = list_first_entry(&transaction->pending_chunks, 74 struct extent_map, list); 75 list_del_init(&em->list); 76 free_extent_map(em); 77 } 78 kmem_cache_free(btrfs_transaction_cachep, transaction); 79 } 80} 81 82static void clear_btree_io_tree(struct extent_io_tree *tree) 83{ 84 spin_lock(&tree->lock); 85 while (!RB_EMPTY_ROOT(&tree->state)) { 86 struct rb_node *node; 87 struct extent_state *state; 88 89 node = rb_first(&tree->state); 90 state = rb_entry(node, struct extent_state, rb_node); 91 rb_erase(&state->rb_node, &tree->state); 92 RB_CLEAR_NODE(&state->rb_node); 93 /* 94 * btree io trees aren't supposed to have tasks waiting for 95 * changes in the flags of extent states ever. 96 */ 97 ASSERT(!waitqueue_active(&state->wq)); 98 free_extent_state(state); 99 100 cond_resched_lock(&tree->lock); 101 } 102 spin_unlock(&tree->lock); 103} 104 105static noinline void switch_commit_roots(struct btrfs_transaction *trans, 106 struct btrfs_fs_info *fs_info) 107{ 108 struct btrfs_root *root, *tmp; 109 110 down_write(&fs_info->commit_root_sem); 111 list_for_each_entry_safe(root, tmp, &trans->switch_commits, 112 dirty_list) { 113 list_del_init(&root->dirty_list); 114 free_extent_buffer(root->commit_root); 115 root->commit_root = btrfs_root_node(root); 116 if (is_fstree(root->objectid)) 117 btrfs_unpin_free_ino(root); 118 clear_btree_io_tree(&root->dirty_log_pages); 119 } 120 up_write(&fs_info->commit_root_sem); 121} 122 123static inline void extwriter_counter_inc(struct btrfs_transaction *trans, 124 unsigned int type) 125{ 126 if (type & TRANS_EXTWRITERS) 127 atomic_inc(&trans->num_extwriters); 128} 129 130static inline void extwriter_counter_dec(struct btrfs_transaction *trans, 131 unsigned int type) 132{ 133 if (type & TRANS_EXTWRITERS) 134 atomic_dec(&trans->num_extwriters); 135} 136 137static inline void extwriter_counter_init(struct btrfs_transaction *trans, 138 unsigned int type) 139{ 140 atomic_set(&trans->num_extwriters, ((type & TRANS_EXTWRITERS) ? 1 : 0)); 141} 142 143static inline int extwriter_counter_read(struct btrfs_transaction *trans) 144{ 145 return atomic_read(&trans->num_extwriters); 146} 147 148/* 149 * either allocate a new transaction or hop into the existing one 150 */ 151static noinline int join_transaction(struct btrfs_root *root, unsigned int type) 152{ 153 struct btrfs_transaction *cur_trans; 154 struct btrfs_fs_info *fs_info = root->fs_info; 155 156 spin_lock(&fs_info->trans_lock); 157loop: 158 /* The file system has been taken offline. No new transactions. */ 159 if (test_bit(BTRFS_FS_STATE_ERROR, &fs_info->fs_state)) { 160 spin_unlock(&fs_info->trans_lock); 161 return -EROFS; 162 } 163 164 cur_trans = fs_info->running_transaction; 165 if (cur_trans) { 166 if (cur_trans->aborted) { 167 spin_unlock(&fs_info->trans_lock); 168 return cur_trans->aborted; 169 } 170 if (btrfs_blocked_trans_types[cur_trans->state] & type) { 171 spin_unlock(&fs_info->trans_lock); 172 return -EBUSY; 173 } 174 atomic_inc(&cur_trans->use_count); 175 atomic_inc(&cur_trans->num_writers); 176 extwriter_counter_inc(cur_trans, type); 177 spin_unlock(&fs_info->trans_lock); 178 return 0; 179 } 180 spin_unlock(&fs_info->trans_lock); 181 182 /* 183 * If we are ATTACH, we just want to catch the current transaction, 184 * and commit it. If there is no transaction, just return ENOENT. 185 */ 186 if (type == TRANS_ATTACH) 187 return -ENOENT; 188 189 /* 190 * JOIN_NOLOCK only happens during the transaction commit, so 191 * it is impossible that ->running_transaction is NULL 192 */ 193 BUG_ON(type == TRANS_JOIN_NOLOCK); 194 195 cur_trans = kmem_cache_alloc(btrfs_transaction_cachep, GFP_NOFS); 196 if (!cur_trans) 197 return -ENOMEM; 198 199 spin_lock(&fs_info->trans_lock); 200 if (fs_info->running_transaction) { 201 /* 202 * someone started a transaction after we unlocked. Make sure 203 * to redo the checks above 204 */ 205 kmem_cache_free(btrfs_transaction_cachep, cur_trans); 206 goto loop; 207 } else if (test_bit(BTRFS_FS_STATE_ERROR, &fs_info->fs_state)) { 208 spin_unlock(&fs_info->trans_lock); 209 kmem_cache_free(btrfs_transaction_cachep, cur_trans); 210 return -EROFS; 211 } 212 213 atomic_set(&cur_trans->num_writers, 1); 214 extwriter_counter_init(cur_trans, type); 215 init_waitqueue_head(&cur_trans->writer_wait); 216 init_waitqueue_head(&cur_trans->commit_wait); 217 cur_trans->state = TRANS_STATE_RUNNING; 218 /* 219 * One for this trans handle, one so it will live on until we 220 * commit the transaction. 221 */ 222 atomic_set(&cur_trans->use_count, 2); 223 cur_trans->have_free_bgs = 0; 224 cur_trans->start_time = get_seconds(); 225 cur_trans->dirty_bg_run = 0; 226 227 cur_trans->delayed_refs.href_root = RB_ROOT; 228 atomic_set(&cur_trans->delayed_refs.num_entries, 0); 229 cur_trans->delayed_refs.num_heads_ready = 0; 230 cur_trans->delayed_refs.pending_csums = 0; 231 cur_trans->delayed_refs.num_heads = 0; 232 cur_trans->delayed_refs.flushing = 0; 233 cur_trans->delayed_refs.run_delayed_start = 0; 234 235 /* 236 * although the tree mod log is per file system and not per transaction, 237 * the log must never go across transaction boundaries. 238 */ 239 smp_mb(); 240 if (!list_empty(&fs_info->tree_mod_seq_list)) 241 WARN(1, KERN_ERR "BTRFS: tree_mod_seq_list not empty when " 242 "creating a fresh transaction\n"); 243 if (!RB_EMPTY_ROOT(&fs_info->tree_mod_log)) 244 WARN(1, KERN_ERR "BTRFS: tree_mod_log rb tree not empty when " 245 "creating a fresh transaction\n"); 246 atomic64_set(&fs_info->tree_mod_seq, 0); 247 248 spin_lock_init(&cur_trans->delayed_refs.lock); 249 250 INIT_LIST_HEAD(&cur_trans->pending_snapshots); 251 INIT_LIST_HEAD(&cur_trans->pending_chunks); 252 INIT_LIST_HEAD(&cur_trans->switch_commits); 253 INIT_LIST_HEAD(&cur_trans->pending_ordered); 254 INIT_LIST_HEAD(&cur_trans->dirty_bgs); 255 INIT_LIST_HEAD(&cur_trans->io_bgs); 256 mutex_init(&cur_trans->cache_write_mutex); 257 cur_trans->num_dirty_bgs = 0; 258 spin_lock_init(&cur_trans->dirty_bgs_lock); 259 list_add_tail(&cur_trans->list, &fs_info->trans_list); 260 extent_io_tree_init(&cur_trans->dirty_pages, 261 fs_info->btree_inode->i_mapping); 262 fs_info->generation++; 263 cur_trans->transid = fs_info->generation; 264 fs_info->running_transaction = cur_trans; 265 cur_trans->aborted = 0; 266 spin_unlock(&fs_info->trans_lock); 267 268 return 0; 269} 270 271/* 272 * this does all the record keeping required to make sure that a reference 273 * counted root is properly recorded in a given transaction. This is required 274 * to make sure the old root from before we joined the transaction is deleted 275 * when the transaction commits 276 */ 277static int record_root_in_trans(struct btrfs_trans_handle *trans, 278 struct btrfs_root *root) 279{ 280 if (test_bit(BTRFS_ROOT_REF_COWS, &root->state) && 281 root->last_trans < trans->transid) { 282 WARN_ON(root == root->fs_info->extent_root); 283 WARN_ON(root->commit_root != root->node); 284 285 /* 286 * see below for IN_TRANS_SETUP usage rules 287 * we have the reloc mutex held now, so there 288 * is only one writer in this function 289 */ 290 set_bit(BTRFS_ROOT_IN_TRANS_SETUP, &root->state); 291 292 /* make sure readers find IN_TRANS_SETUP before 293 * they find our root->last_trans update 294 */ 295 smp_wmb(); 296 297 spin_lock(&root->fs_info->fs_roots_radix_lock); 298 if (root->last_trans == trans->transid) { 299 spin_unlock(&root->fs_info->fs_roots_radix_lock); 300 return 0; 301 } 302 radix_tree_tag_set(&root->fs_info->fs_roots_radix, 303 (unsigned long)root->root_key.objectid, 304 BTRFS_ROOT_TRANS_TAG); 305 spin_unlock(&root->fs_info->fs_roots_radix_lock); 306 root->last_trans = trans->transid; 307 308 /* this is pretty tricky. We don't want to 309 * take the relocation lock in btrfs_record_root_in_trans 310 * unless we're really doing the first setup for this root in 311 * this transaction. 312 * 313 * Normally we'd use root->last_trans as a flag to decide 314 * if we want to take the expensive mutex. 315 * 316 * But, we have to set root->last_trans before we 317 * init the relocation root, otherwise, we trip over warnings 318 * in ctree.c. The solution used here is to flag ourselves 319 * with root IN_TRANS_SETUP. When this is 1, we're still 320 * fixing up the reloc trees and everyone must wait. 321 * 322 * When this is zero, they can trust root->last_trans and fly 323 * through btrfs_record_root_in_trans without having to take the 324 * lock. smp_wmb() makes sure that all the writes above are 325 * done before we pop in the zero below 326 */ 327 btrfs_init_reloc_root(trans, root); 328 smp_mb__before_atomic(); 329 clear_bit(BTRFS_ROOT_IN_TRANS_SETUP, &root->state); 330 } 331 return 0; 332} 333 334 335int btrfs_record_root_in_trans(struct btrfs_trans_handle *trans, 336 struct btrfs_root *root) 337{ 338 if (!test_bit(BTRFS_ROOT_REF_COWS, &root->state)) 339 return 0; 340 341 /* 342 * see record_root_in_trans for comments about IN_TRANS_SETUP usage 343 * and barriers 344 */ 345 smp_rmb(); 346 if (root->last_trans == trans->transid && 347 !test_bit(BTRFS_ROOT_IN_TRANS_SETUP, &root->state)) 348 return 0; 349 350 mutex_lock(&root->fs_info->reloc_mutex); 351 record_root_in_trans(trans, root); 352 mutex_unlock(&root->fs_info->reloc_mutex); 353 354 return 0; 355} 356 357static inline int is_transaction_blocked(struct btrfs_transaction *trans) 358{ 359 return (trans->state >= TRANS_STATE_BLOCKED && 360 trans->state < TRANS_STATE_UNBLOCKED && 361 !trans->aborted); 362} 363 364/* wait for commit against the current transaction to become unblocked 365 * when this is done, it is safe to start a new transaction, but the current 366 * transaction might not be fully on disk. 367 */ 368static void wait_current_trans(struct btrfs_root *root) 369{ 370 struct btrfs_transaction *cur_trans; 371 372 spin_lock(&root->fs_info->trans_lock); 373 cur_trans = root->fs_info->running_transaction; 374 if (cur_trans && is_transaction_blocked(cur_trans)) { 375 atomic_inc(&cur_trans->use_count); 376 spin_unlock(&root->fs_info->trans_lock); 377 378 wait_event(root->fs_info->transaction_wait, 379 cur_trans->state >= TRANS_STATE_UNBLOCKED || 380 cur_trans->aborted); 381 btrfs_put_transaction(cur_trans); 382 } else { 383 spin_unlock(&root->fs_info->trans_lock); 384 } 385} 386 387static int may_wait_transaction(struct btrfs_root *root, int type) 388{ 389 if (root->fs_info->log_root_recovering) 390 return 0; 391 392 if (type == TRANS_USERSPACE) 393 return 1; 394 395 if (type == TRANS_START && 396 !atomic_read(&root->fs_info->open_ioctl_trans)) 397 return 1; 398 399 return 0; 400} 401 402static inline bool need_reserve_reloc_root(struct btrfs_root *root) 403{ 404 if (!root->fs_info->reloc_ctl || 405 !test_bit(BTRFS_ROOT_REF_COWS, &root->state) || 406 root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID || 407 root->reloc_root) 408 return false; 409 410 return true; 411} 412 413static struct btrfs_trans_handle * 414start_transaction(struct btrfs_root *root, u64 num_items, unsigned int type, 415 enum btrfs_reserve_flush_enum flush) 416{ 417 struct btrfs_trans_handle *h; 418 struct btrfs_transaction *cur_trans; 419 u64 num_bytes = 0; 420 u64 qgroup_reserved = 0; 421 bool reloc_reserved = false; 422 int ret; 423 424 /* Send isn't supposed to start transactions. */ 425 ASSERT(current->journal_info != BTRFS_SEND_TRANS_STUB); 426 427 if (test_bit(BTRFS_FS_STATE_ERROR, &root->fs_info->fs_state)) 428 return ERR_PTR(-EROFS); 429 430 if (current->journal_info) { 431 WARN_ON(type & TRANS_EXTWRITERS); 432 h = current->journal_info; 433 h->use_count++; 434 WARN_ON(h->use_count > 2); 435 h->orig_rsv = h->block_rsv; 436 h->block_rsv = NULL; 437 goto got_it; 438 } 439 440 /* 441 * Do the reservation before we join the transaction so we can do all 442 * the appropriate flushing if need be. 443 */ 444 if (num_items > 0 && root != root->fs_info->chunk_root) { 445 if (root->fs_info->quota_enabled && 446 is_fstree(root->root_key.objectid)) { 447 qgroup_reserved = num_items * root->nodesize; 448 ret = btrfs_qgroup_reserve(root, qgroup_reserved); 449 if (ret) 450 return ERR_PTR(ret); 451 } 452 453 num_bytes = btrfs_calc_trans_metadata_size(root, num_items); 454 /* 455 * Do the reservation for the relocation root creation 456 */ 457 if (need_reserve_reloc_root(root)) { 458 num_bytes += root->nodesize; 459 reloc_reserved = true; 460 } 461 462 ret = btrfs_block_rsv_add(root, 463 &root->fs_info->trans_block_rsv, 464 num_bytes, flush); 465 if (ret) 466 goto reserve_fail; 467 } 468again: 469 h = kmem_cache_alloc(btrfs_trans_handle_cachep, GFP_NOFS); 470 if (!h) { 471 ret = -ENOMEM; 472 goto alloc_fail; 473 } 474 475 /* 476 * If we are JOIN_NOLOCK we're already committing a transaction and 477 * waiting on this guy, so we don't need to do the sb_start_intwrite 478 * because we're already holding a ref. We need this because we could 479 * have raced in and did an fsync() on a file which can kick a commit 480 * and then we deadlock with somebody doing a freeze. 481 * 482 * If we are ATTACH, it means we just want to catch the current 483 * transaction and commit it, so we needn't do sb_start_intwrite(). 484 */ 485 if (type & __TRANS_FREEZABLE) 486 sb_start_intwrite(root->fs_info->sb); 487 488 if (may_wait_transaction(root, type)) 489 wait_current_trans(root); 490 491 do { 492 ret = join_transaction(root, type); 493 if (ret == -EBUSY) { 494 wait_current_trans(root); 495 if (unlikely(type == TRANS_ATTACH)) 496 ret = -ENOENT; 497 } 498 } while (ret == -EBUSY); 499 500 if (ret < 0) { 501 /* We must get the transaction if we are JOIN_NOLOCK. */ 502 BUG_ON(type == TRANS_JOIN_NOLOCK); 503 goto join_fail; 504 } 505 506 cur_trans = root->fs_info->running_transaction; 507 508 h->transid = cur_trans->transid; 509 h->transaction = cur_trans; 510 h->blocks_used = 0; 511 h->bytes_reserved = 0; 512 h->root = root; 513 h->delayed_ref_updates = 0; 514 h->use_count = 1; 515 h->adding_csums = 0; 516 h->block_rsv = NULL; 517 h->orig_rsv = NULL; 518 h->aborted = 0; 519 h->qgroup_reserved = 0; 520 h->delayed_ref_elem.seq = 0; 521 h->type = type; 522 h->allocating_chunk = false; 523 h->reloc_reserved = false; 524 h->sync = false; 525 INIT_LIST_HEAD(&h->qgroup_ref_list); 526 INIT_LIST_HEAD(&h->new_bgs); 527 INIT_LIST_HEAD(&h->ordered); 528 529 smp_mb(); 530 if (cur_trans->state >= TRANS_STATE_BLOCKED && 531 may_wait_transaction(root, type)) { 532 current->journal_info = h; 533 btrfs_commit_transaction(h, root); 534 goto again; 535 } 536 537 if (num_bytes) { 538 trace_btrfs_space_reservation(root->fs_info, "transaction", 539 h->transid, num_bytes, 1); 540 h->block_rsv = &root->fs_info->trans_block_rsv; 541 h->bytes_reserved = num_bytes; 542 h->reloc_reserved = reloc_reserved; 543 } 544 h->qgroup_reserved = qgroup_reserved; 545 546got_it: 547 btrfs_record_root_in_trans(h, root); 548 549 if (!current->journal_info && type != TRANS_USERSPACE) 550 current->journal_info = h; 551 return h; 552 553join_fail: 554 if (type & __TRANS_FREEZABLE) 555 sb_end_intwrite(root->fs_info->sb); 556 kmem_cache_free(btrfs_trans_handle_cachep, h); 557alloc_fail: 558 if (num_bytes) 559 btrfs_block_rsv_release(root, &root->fs_info->trans_block_rsv, 560 num_bytes); 561reserve_fail: 562 if (qgroup_reserved) 563 btrfs_qgroup_free(root, qgroup_reserved); 564 return ERR_PTR(ret); 565} 566 567struct btrfs_trans_handle *btrfs_start_transaction(struct btrfs_root *root, 568 int num_items) 569{ 570 return start_transaction(root, num_items, TRANS_START, 571 BTRFS_RESERVE_FLUSH_ALL); 572} 573 574struct btrfs_trans_handle *btrfs_start_transaction_lflush( 575 struct btrfs_root *root, int num_items) 576{ 577 return start_transaction(root, num_items, TRANS_START, 578 BTRFS_RESERVE_FLUSH_LIMIT); 579} 580 581struct btrfs_trans_handle *btrfs_join_transaction(struct btrfs_root *root) 582{ 583 return start_transaction(root, 0, TRANS_JOIN, 0); 584} 585 586struct btrfs_trans_handle *btrfs_join_transaction_nolock(struct btrfs_root *root) 587{ 588 return start_transaction(root, 0, TRANS_JOIN_NOLOCK, 0); 589} 590 591struct btrfs_trans_handle *btrfs_start_ioctl_transaction(struct btrfs_root *root) 592{ 593 return start_transaction(root, 0, TRANS_USERSPACE, 0); 594} 595 596/* 597 * btrfs_attach_transaction() - catch the running transaction 598 * 599 * It is used when we want to commit the current the transaction, but 600 * don't want to start a new one. 601 * 602 * Note: If this function return -ENOENT, it just means there is no 603 * running transaction. But it is possible that the inactive transaction 604 * is still in the memory, not fully on disk. If you hope there is no 605 * inactive transaction in the fs when -ENOENT is returned, you should 606 * invoke 607 * btrfs_attach_transaction_barrier() 608 */ 609struct btrfs_trans_handle *btrfs_attach_transaction(struct btrfs_root *root) 610{ 611 return start_transaction(root, 0, TRANS_ATTACH, 0); 612} 613 614/* 615 * btrfs_attach_transaction_barrier() - catch the running transaction 616 * 617 * It is similar to the above function, the differentia is this one 618 * will wait for all the inactive transactions until they fully 619 * complete. 620 */ 621struct btrfs_trans_handle * 622btrfs_attach_transaction_barrier(struct btrfs_root *root) 623{ 624 struct btrfs_trans_handle *trans; 625 626 trans = start_transaction(root, 0, TRANS_ATTACH, 0); 627 if (IS_ERR(trans) && PTR_ERR(trans) == -ENOENT) 628 btrfs_wait_for_commit(root, 0); 629 630 return trans; 631} 632 633/* wait for a transaction commit to be fully complete */ 634static noinline void wait_for_commit(struct btrfs_root *root, 635 struct btrfs_transaction *commit) 636{ 637 wait_event(commit->commit_wait, commit->state == TRANS_STATE_COMPLETED); 638} 639 640int btrfs_wait_for_commit(struct btrfs_root *root, u64 transid) 641{ 642 struct btrfs_transaction *cur_trans = NULL, *t; 643 int ret = 0; 644 645 if (transid) { 646 if (transid <= root->fs_info->last_trans_committed) 647 goto out; 648 649 /* find specified transaction */ 650 spin_lock(&root->fs_info->trans_lock); 651 list_for_each_entry(t, &root->fs_info->trans_list, list) { 652 if (t->transid == transid) { 653 cur_trans = t; 654 atomic_inc(&cur_trans->use_count); 655 ret = 0; 656 break; 657 } 658 if (t->transid > transid) { 659 ret = 0; 660 break; 661 } 662 } 663 spin_unlock(&root->fs_info->trans_lock); 664 665 /* 666 * The specified transaction doesn't exist, or we 667 * raced with btrfs_commit_transaction 668 */ 669 if (!cur_trans) { 670 if (transid > root->fs_info->last_trans_committed) 671 ret = -EINVAL; 672 goto out; 673 } 674 } else { 675 /* find newest transaction that is committing | committed */ 676 spin_lock(&root->fs_info->trans_lock); 677 list_for_each_entry_reverse(t, &root->fs_info->trans_list, 678 list) { 679 if (t->state >= TRANS_STATE_COMMIT_START) { 680 if (t->state == TRANS_STATE_COMPLETED) 681 break; 682 cur_trans = t; 683 atomic_inc(&cur_trans->use_count); 684 break; 685 } 686 } 687 spin_unlock(&root->fs_info->trans_lock); 688 if (!cur_trans) 689 goto out; /* nothing committing|committed */ 690 } 691 692 wait_for_commit(root, cur_trans); 693 btrfs_put_transaction(cur_trans); 694out: 695 return ret; 696} 697 698void btrfs_throttle(struct btrfs_root *root) 699{ 700 if (!atomic_read(&root->fs_info->open_ioctl_trans)) 701 wait_current_trans(root); 702} 703 704static int should_end_transaction(struct btrfs_trans_handle *trans, 705 struct btrfs_root *root) 706{ 707 if (root->fs_info->global_block_rsv.space_info->full && 708 btrfs_check_space_for_delayed_refs(trans, root)) 709 return 1; 710 711 return !!btrfs_block_rsv_check(root, &root->fs_info->global_block_rsv, 5); 712} 713 714int btrfs_should_end_transaction(struct btrfs_trans_handle *trans, 715 struct btrfs_root *root) 716{ 717 struct btrfs_transaction *cur_trans = trans->transaction; 718 int updates; 719 int err; 720 721 smp_mb(); 722 if (cur_trans->state >= TRANS_STATE_BLOCKED || 723 cur_trans->delayed_refs.flushing) 724 return 1; 725 726 updates = trans->delayed_ref_updates; 727 trans->delayed_ref_updates = 0; 728 if (updates) { 729 err = btrfs_run_delayed_refs(trans, root, updates * 2); 730 if (err) /* Error code will also eval true */ 731 return err; 732 } 733 734 return should_end_transaction(trans, root); 735} 736 737static int __btrfs_end_transaction(struct btrfs_trans_handle *trans, 738 struct btrfs_root *root, int throttle) 739{ 740 struct btrfs_transaction *cur_trans = trans->transaction; 741 struct btrfs_fs_info *info = root->fs_info; 742 unsigned long cur = trans->delayed_ref_updates; 743 int lock = (trans->type != TRANS_JOIN_NOLOCK); 744 int err = 0; 745 int must_run_delayed_refs = 0; 746 747 if (trans->use_count > 1) { 748 trans->use_count--; 749 trans->block_rsv = trans->orig_rsv; 750 return 0; 751 } 752 753 btrfs_trans_release_metadata(trans, root); 754 trans->block_rsv = NULL; 755 756 if (!list_empty(&trans->new_bgs)) 757 btrfs_create_pending_block_groups(trans, root); 758 759 if (!list_empty(&trans->ordered)) { 760 spin_lock(&info->trans_lock); 761 list_splice_init(&trans->ordered, &cur_trans->pending_ordered); 762 spin_unlock(&info->trans_lock); 763 } 764 765 trans->delayed_ref_updates = 0; 766 if (!trans->sync) { 767 must_run_delayed_refs = 768 btrfs_should_throttle_delayed_refs(trans, root); 769 cur = max_t(unsigned long, cur, 32); 770 771 /* 772 * don't make the caller wait if they are from a NOLOCK 773 * or ATTACH transaction, it will deadlock with commit 774 */ 775 if (must_run_delayed_refs == 1 && 776 (trans->type & (__TRANS_JOIN_NOLOCK | __TRANS_ATTACH))) 777 must_run_delayed_refs = 2; 778 } 779 780 if (trans->qgroup_reserved) { 781 /* 782 * the same root has to be passed here between start_transaction 783 * and end_transaction. Subvolume quota depends on this. 784 */ 785 btrfs_qgroup_free(trans->root, trans->qgroup_reserved); 786 trans->qgroup_reserved = 0; 787 } 788 789 btrfs_trans_release_metadata(trans, root); 790 trans->block_rsv = NULL; 791 792 if (!list_empty(&trans->new_bgs)) 793 btrfs_create_pending_block_groups(trans, root); 794 795 if (lock && !atomic_read(&root->fs_info->open_ioctl_trans) && 796 should_end_transaction(trans, root) && 797 ACCESS_ONCE(cur_trans->state) == TRANS_STATE_RUNNING) { 798 spin_lock(&info->trans_lock); 799 if (cur_trans->state == TRANS_STATE_RUNNING) 800 cur_trans->state = TRANS_STATE_BLOCKED; 801 spin_unlock(&info->trans_lock); 802 } 803 804 if (lock && ACCESS_ONCE(cur_trans->state) == TRANS_STATE_BLOCKED) { 805 if (throttle) 806 return btrfs_commit_transaction(trans, root); 807 else 808 wake_up_process(info->transaction_kthread); 809 } 810 811 if (trans->type & __TRANS_FREEZABLE) 812 sb_end_intwrite(root->fs_info->sb); 813 814 WARN_ON(cur_trans != info->running_transaction); 815 WARN_ON(atomic_read(&cur_trans->num_writers) < 1); 816 atomic_dec(&cur_trans->num_writers); 817 extwriter_counter_dec(cur_trans, trans->type); 818 819 smp_mb(); 820 if (waitqueue_active(&cur_trans->writer_wait)) 821 wake_up(&cur_trans->writer_wait); 822 btrfs_put_transaction(cur_trans); 823 824 if (current->journal_info == trans) 825 current->journal_info = NULL; 826 827 if (throttle) 828 btrfs_run_delayed_iputs(root); 829 830 if (trans->aborted || 831 test_bit(BTRFS_FS_STATE_ERROR, &root->fs_info->fs_state)) { 832 wake_up_process(info->transaction_kthread); 833 err = -EIO; 834 } 835 assert_qgroups_uptodate(trans); 836 837 kmem_cache_free(btrfs_trans_handle_cachep, trans); 838 if (must_run_delayed_refs) { 839 btrfs_async_run_delayed_refs(root, cur, 840 must_run_delayed_refs == 1); 841 } 842 return err; 843} 844 845int btrfs_end_transaction(struct btrfs_trans_handle *trans, 846 struct btrfs_root *root) 847{ 848 return __btrfs_end_transaction(trans, root, 0); 849} 850 851int btrfs_end_transaction_throttle(struct btrfs_trans_handle *trans, 852 struct btrfs_root *root) 853{ 854 return __btrfs_end_transaction(trans, root, 1); 855} 856 857/* 858 * when btree blocks are allocated, they have some corresponding bits set for 859 * them in one of two extent_io trees. This is used to make sure all of 860 * those extents are sent to disk but does not wait on them 861 */ 862int btrfs_write_marked_extents(struct btrfs_root *root, 863 struct extent_io_tree *dirty_pages, int mark) 864{ 865 int err = 0; 866 int werr = 0; 867 struct address_space *mapping = root->fs_info->btree_inode->i_mapping; 868 struct extent_state *cached_state = NULL; 869 u64 start = 0; 870 u64 end; 871 872 while (!find_first_extent_bit(dirty_pages, start, &start, &end, 873 mark, &cached_state)) { 874 bool wait_writeback = false; 875 876 err = convert_extent_bit(dirty_pages, start, end, 877 EXTENT_NEED_WAIT, 878 mark, &cached_state, GFP_NOFS); 879 /* 880 * convert_extent_bit can return -ENOMEM, which is most of the 881 * time a temporary error. So when it happens, ignore the error 882 * and wait for writeback of this range to finish - because we 883 * failed to set the bit EXTENT_NEED_WAIT for the range, a call 884 * to btrfs_wait_marked_extents() would not know that writeback 885 * for this range started and therefore wouldn't wait for it to 886 * finish - we don't want to commit a superblock that points to 887 * btree nodes/leafs for which writeback hasn't finished yet 888 * (and without errors). 889 * We cleanup any entries left in the io tree when committing 890 * the transaction (through clear_btree_io_tree()). 891 */ 892 if (err == -ENOMEM) { 893 err = 0; 894 wait_writeback = true; 895 } 896 if (!err) 897 err = filemap_fdatawrite_range(mapping, start, end); 898 if (err) 899 werr = err; 900 else if (wait_writeback) 901 werr = filemap_fdatawait_range(mapping, start, end); 902 free_extent_state(cached_state); 903 cached_state = NULL; 904 cond_resched(); 905 start = end + 1; 906 } 907 return werr; 908} 909 910/* 911 * when btree blocks are allocated, they have some corresponding bits set for 912 * them in one of two extent_io trees. This is used to make sure all of 913 * those extents are on disk for transaction or log commit. We wait 914 * on all the pages and clear them from the dirty pages state tree 915 */ 916int btrfs_wait_marked_extents(struct btrfs_root *root, 917 struct extent_io_tree *dirty_pages, int mark) 918{ 919 int err = 0; 920 int werr = 0; 921 struct address_space *mapping = root->fs_info->btree_inode->i_mapping; 922 struct extent_state *cached_state = NULL; 923 u64 start = 0; 924 u64 end; 925 struct btrfs_inode *btree_ino = BTRFS_I(root->fs_info->btree_inode); 926 bool errors = false; 927 928 while (!find_first_extent_bit(dirty_pages, start, &start, &end, 929 EXTENT_NEED_WAIT, &cached_state)) { 930 /* 931 * Ignore -ENOMEM errors returned by clear_extent_bit(). 932 * When committing the transaction, we'll remove any entries 933 * left in the io tree. For a log commit, we don't remove them 934 * after committing the log because the tree can be accessed 935 * concurrently - we do it only at transaction commit time when 936 * it's safe to do it (through clear_btree_io_tree()). 937 */ 938 err = clear_extent_bit(dirty_pages, start, end, 939 EXTENT_NEED_WAIT, 940 0, 0, &cached_state, GFP_NOFS); 941 if (err == -ENOMEM) 942 err = 0; 943 if (!err) 944 err = filemap_fdatawait_range(mapping, start, end); 945 if (err) 946 werr = err; 947 free_extent_state(cached_state); 948 cached_state = NULL; 949 cond_resched(); 950 start = end + 1; 951 } 952 if (err) 953 werr = err; 954 955 if (root->root_key.objectid == BTRFS_TREE_LOG_OBJECTID) { 956 if ((mark & EXTENT_DIRTY) && 957 test_and_clear_bit(BTRFS_INODE_BTREE_LOG1_ERR, 958 &btree_ino->runtime_flags)) 959 errors = true; 960 961 if ((mark & EXTENT_NEW) && 962 test_and_clear_bit(BTRFS_INODE_BTREE_LOG2_ERR, 963 &btree_ino->runtime_flags)) 964 errors = true; 965 } else { 966 if (test_and_clear_bit(BTRFS_INODE_BTREE_ERR, 967 &btree_ino->runtime_flags)) 968 errors = true; 969 } 970 971 if (errors && !werr) 972 werr = -EIO; 973 974 return werr; 975} 976 977/* 978 * when btree blocks are allocated, they have some corresponding bits set for 979 * them in one of two extent_io trees. This is used to make sure all of 980 * those extents are on disk for transaction or log commit 981 */ 982static int btrfs_write_and_wait_marked_extents(struct btrfs_root *root, 983 struct extent_io_tree *dirty_pages, int mark) 984{ 985 int ret; 986 int ret2; 987 struct blk_plug plug; 988 989 blk_start_plug(&plug); 990 ret = btrfs_write_marked_extents(root, dirty_pages, mark); 991 blk_finish_plug(&plug); 992 ret2 = btrfs_wait_marked_extents(root, dirty_pages, mark); 993 994 if (ret) 995 return ret; 996 if (ret2) 997 return ret2; 998 return 0; 999} 1000 1001static int btrfs_write_and_wait_transaction(struct btrfs_trans_handle *trans, 1002 struct btrfs_root *root) 1003{ 1004 int ret; 1005 1006 ret = btrfs_write_and_wait_marked_extents(root, 1007 &trans->transaction->dirty_pages, 1008 EXTENT_DIRTY); 1009 clear_btree_io_tree(&trans->transaction->dirty_pages); 1010 1011 return ret; 1012} 1013 1014/* 1015 * this is used to update the root pointer in the tree of tree roots. 1016 * 1017 * But, in the case of the extent allocation tree, updating the root 1018 * pointer may allocate blocks which may change the root of the extent 1019 * allocation tree. 1020 * 1021 * So, this loops and repeats and makes sure the cowonly root didn't 1022 * change while the root pointer was being updated in the metadata. 1023 */ 1024static int update_cowonly_root(struct btrfs_trans_handle *trans, 1025 struct btrfs_root *root) 1026{ 1027 int ret; 1028 u64 old_root_bytenr; 1029 u64 old_root_used; 1030 struct btrfs_root *tree_root = root->fs_info->tree_root; 1031 1032 old_root_used = btrfs_root_used(&root->root_item); 1033 1034 while (1) { 1035 old_root_bytenr = btrfs_root_bytenr(&root->root_item); 1036 if (old_root_bytenr == root->node->start && 1037 old_root_used == btrfs_root_used(&root->root_item)) 1038 break; 1039 1040 btrfs_set_root_node(&root->root_item, root->node); 1041 ret = btrfs_update_root(trans, tree_root, 1042 &root->root_key, 1043 &root->root_item); 1044 if (ret) 1045 return ret; 1046 1047 old_root_used = btrfs_root_used(&root->root_item); 1048 } 1049 1050 return 0; 1051} 1052 1053/* 1054 * update all the cowonly tree roots on disk 1055 * 1056 * The error handling in this function may not be obvious. Any of the 1057 * failures will cause the file system to go offline. We still need 1058 * to clean up the delayed refs. 1059 */ 1060static noinline int commit_cowonly_roots(struct btrfs_trans_handle *trans, 1061 struct btrfs_root *root) 1062{ 1063 struct btrfs_fs_info *fs_info = root->fs_info; 1064 struct list_head *dirty_bgs = &trans->transaction->dirty_bgs; 1065 struct list_head *io_bgs = &trans->transaction->io_bgs; 1066 struct list_head *next; 1067 struct extent_buffer *eb; 1068 int ret; 1069 1070 eb = btrfs_lock_root_node(fs_info->tree_root); 1071 ret = btrfs_cow_block(trans, fs_info->tree_root, eb, NULL, 1072 0, &eb); 1073 btrfs_tree_unlock(eb); 1074 free_extent_buffer(eb); 1075 1076 if (ret) 1077 return ret; 1078 1079 ret = btrfs_run_delayed_refs(trans, root, (unsigned long)-1); 1080 if (ret) 1081 return ret; 1082 1083 ret = btrfs_run_dev_stats(trans, root->fs_info); 1084 if (ret) 1085 return ret; 1086 ret = btrfs_run_dev_replace(trans, root->fs_info); 1087 if (ret) 1088 return ret; 1089 ret = btrfs_run_qgroups(trans, root->fs_info); 1090 if (ret) 1091 return ret; 1092 1093 ret = btrfs_setup_space_cache(trans, root); 1094 if (ret) 1095 return ret; 1096 1097 /* run_qgroups might have added some more refs */ 1098 ret = btrfs_run_delayed_refs(trans, root, (unsigned long)-1); 1099 if (ret) 1100 return ret; 1101again: 1102 while (!list_empty(&fs_info->dirty_cowonly_roots)) { 1103 next = fs_info->dirty_cowonly_roots.next; 1104 list_del_init(next); 1105 root = list_entry(next, struct btrfs_root, dirty_list); 1106 clear_bit(BTRFS_ROOT_DIRTY, &root->state); 1107 1108 if (root != fs_info->extent_root) 1109 list_add_tail(&root->dirty_list, 1110 &trans->transaction->switch_commits); 1111 ret = update_cowonly_root(trans, root); 1112 if (ret) 1113 return ret; 1114 ret = btrfs_run_delayed_refs(trans, root, (unsigned long)-1); 1115 if (ret) 1116 return ret; 1117 } 1118 1119 while (!list_empty(dirty_bgs) || !list_empty(io_bgs)) { 1120 ret = btrfs_write_dirty_block_groups(trans, root); 1121 if (ret) 1122 return ret; 1123 ret = btrfs_run_delayed_refs(trans, root, (unsigned long)-1); 1124 if (ret) 1125 return ret; 1126 } 1127 1128 if (!list_empty(&fs_info->dirty_cowonly_roots)) 1129 goto again; 1130 1131 list_add_tail(&fs_info->extent_root->dirty_list, 1132 &trans->transaction->switch_commits); 1133 btrfs_after_dev_replace_commit(fs_info); 1134 1135 return 0; 1136} 1137 1138/* 1139 * dead roots are old snapshots that need to be deleted. This allocates 1140 * a dirty root struct and adds it into the list of dead roots that need to 1141 * be deleted 1142 */ 1143void btrfs_add_dead_root(struct btrfs_root *root) 1144{ 1145 spin_lock(&root->fs_info->trans_lock); 1146 if (list_empty(&root->root_list)) 1147 list_add_tail(&root->root_list, &root->fs_info->dead_roots); 1148 spin_unlock(&root->fs_info->trans_lock); 1149} 1150 1151/* 1152 * update all the cowonly tree roots on disk 1153 */ 1154static noinline int commit_fs_roots(struct btrfs_trans_handle *trans, 1155 struct btrfs_root *root) 1156{ 1157 struct btrfs_root *gang[8]; 1158 struct btrfs_fs_info *fs_info = root->fs_info; 1159 int i; 1160 int ret; 1161 int err = 0; 1162 1163 spin_lock(&fs_info->fs_roots_radix_lock); 1164 while (1) { 1165 ret = radix_tree_gang_lookup_tag(&fs_info->fs_roots_radix, 1166 (void **)gang, 0, 1167 ARRAY_SIZE(gang), 1168 BTRFS_ROOT_TRANS_TAG); 1169 if (ret == 0) 1170 break; 1171 for (i = 0; i < ret; i++) { 1172 root = gang[i]; 1173 radix_tree_tag_clear(&fs_info->fs_roots_radix, 1174 (unsigned long)root->root_key.objectid, 1175 BTRFS_ROOT_TRANS_TAG); 1176 spin_unlock(&fs_info->fs_roots_radix_lock); 1177 1178 btrfs_free_log(trans, root); 1179 btrfs_update_reloc_root(trans, root); 1180 btrfs_orphan_commit_root(trans, root); 1181 1182 btrfs_save_ino_cache(root, trans); 1183 1184 /* see comments in should_cow_block() */ 1185 clear_bit(BTRFS_ROOT_FORCE_COW, &root->state); 1186 smp_mb__after_atomic(); 1187 1188 if (root->commit_root != root->node) { 1189 list_add_tail(&root->dirty_list, 1190 &trans->transaction->switch_commits); 1191 btrfs_set_root_node(&root->root_item, 1192 root->node); 1193 } 1194 1195 err = btrfs_update_root(trans, fs_info->tree_root, 1196 &root->root_key, 1197 &root->root_item); 1198 spin_lock(&fs_info->fs_roots_radix_lock); 1199 if (err) 1200 break; 1201 } 1202 } 1203 spin_unlock(&fs_info->fs_roots_radix_lock); 1204 return err; 1205} 1206 1207/* 1208 * defrag a given btree. 1209 * Every leaf in the btree is read and defragged. 1210 */ 1211int btrfs_defrag_root(struct btrfs_root *root) 1212{ 1213 struct btrfs_fs_info *info = root->fs_info; 1214 struct btrfs_trans_handle *trans; 1215 int ret; 1216 1217 if (test_and_set_bit(BTRFS_ROOT_DEFRAG_RUNNING, &root->state)) 1218 return 0; 1219 1220 while (1) { 1221 trans = btrfs_start_transaction(root, 0); 1222 if (IS_ERR(trans)) 1223 return PTR_ERR(trans); 1224 1225 ret = btrfs_defrag_leaves(trans, root); 1226 1227 btrfs_end_transaction(trans, root); 1228 btrfs_btree_balance_dirty(info->tree_root); 1229 cond_resched(); 1230 1231 if (btrfs_fs_closing(root->fs_info) || ret != -EAGAIN) 1232 break; 1233 1234 if (btrfs_defrag_cancelled(root->fs_info)) { 1235 pr_debug("BTRFS: defrag_root cancelled\n"); 1236 ret = -EAGAIN; 1237 break; 1238 } 1239 } 1240 clear_bit(BTRFS_ROOT_DEFRAG_RUNNING, &root->state); 1241 return ret; 1242} 1243 1244/* 1245 * new snapshots need to be created at a very specific time in the 1246 * transaction commit. This does the actual creation. 1247 * 1248 * Note: 1249 * If the error which may affect the commitment of the current transaction 1250 * happens, we should return the error number. If the error which just affect 1251 * the creation of the pending snapshots, just return 0. 1252 */ 1253static noinline int create_pending_snapshot(struct btrfs_trans_handle *trans, 1254 struct btrfs_fs_info *fs_info, 1255 struct btrfs_pending_snapshot *pending) 1256{ 1257 struct btrfs_key key; 1258 struct btrfs_root_item *new_root_item; 1259 struct btrfs_root *tree_root = fs_info->tree_root; 1260 struct btrfs_root *root = pending->root; 1261 struct btrfs_root *parent_root; 1262 struct btrfs_block_rsv *rsv; 1263 struct inode *parent_inode; 1264 struct btrfs_path *path; 1265 struct btrfs_dir_item *dir_item; 1266 struct dentry *dentry; 1267 struct extent_buffer *tmp; 1268 struct extent_buffer *old; 1269 struct timespec cur_time = CURRENT_TIME; 1270 int ret = 0; 1271 u64 to_reserve = 0; 1272 u64 index = 0; 1273 u64 objectid; 1274 u64 root_flags; 1275 uuid_le new_uuid; 1276 1277 path = btrfs_alloc_path(); 1278 if (!path) { 1279 pending->error = -ENOMEM; 1280 return 0; 1281 } 1282 1283 new_root_item = kmalloc(sizeof(*new_root_item), GFP_NOFS); 1284 if (!new_root_item) { 1285 pending->error = -ENOMEM; 1286 goto root_item_alloc_fail; 1287 } 1288 1289 pending->error = btrfs_find_free_objectid(tree_root, &objectid); 1290 if (pending->error) 1291 goto no_free_objectid; 1292 1293 btrfs_reloc_pre_snapshot(trans, pending, &to_reserve); 1294 1295 if (to_reserve > 0) { 1296 pending->error = btrfs_block_rsv_add(root, 1297 &pending->block_rsv, 1298 to_reserve, 1299 BTRFS_RESERVE_NO_FLUSH); 1300 if (pending->error) 1301 goto no_free_objectid; 1302 } 1303 1304 key.objectid = objectid; 1305 key.offset = (u64)-1; 1306 key.type = BTRFS_ROOT_ITEM_KEY; 1307 1308 rsv = trans->block_rsv; 1309 trans->block_rsv = &pending->block_rsv; 1310 trans->bytes_reserved = trans->block_rsv->reserved; 1311 1312 dentry = pending->dentry; 1313 parent_inode = pending->dir; 1314 parent_root = BTRFS_I(parent_inode)->root; 1315 record_root_in_trans(trans, parent_root); 1316 1317 /* 1318 * insert the directory item 1319 */ 1320 ret = btrfs_set_inode_index(parent_inode, &index); 1321 BUG_ON(ret); /* -ENOMEM */ 1322 1323 /* check if there is a file/dir which has the same name. */ 1324 dir_item = btrfs_lookup_dir_item(NULL, parent_root, path, 1325 btrfs_ino(parent_inode), 1326 dentry->d_name.name, 1327 dentry->d_name.len, 0); 1328 if (dir_item != NULL && !IS_ERR(dir_item)) { 1329 pending->error = -EEXIST; 1330 goto dir_item_existed; 1331 } else if (IS_ERR(dir_item)) { 1332 ret = PTR_ERR(dir_item); 1333 btrfs_abort_transaction(trans, root, ret); 1334 goto fail; 1335 } 1336 btrfs_release_path(path); 1337 1338 /* 1339 * pull in the delayed directory update 1340 * and the delayed inode item 1341 * otherwise we corrupt the FS during 1342 * snapshot 1343 */ 1344 ret = btrfs_run_delayed_items(trans, root); 1345 if (ret) { /* Transaction aborted */ 1346 btrfs_abort_transaction(trans, root, ret); 1347 goto fail; 1348 } 1349 1350 record_root_in_trans(trans, root); 1351 btrfs_set_root_last_snapshot(&root->root_item, trans->transid); 1352 memcpy(new_root_item, &root->root_item, sizeof(*new_root_item)); 1353 btrfs_check_and_init_root_item(new_root_item); 1354 1355 root_flags = btrfs_root_flags(new_root_item); 1356 if (pending->readonly) 1357 root_flags |= BTRFS_ROOT_SUBVOL_RDONLY; 1358 else 1359 root_flags &= ~BTRFS_ROOT_SUBVOL_RDONLY; 1360 btrfs_set_root_flags(new_root_item, root_flags); 1361 1362 btrfs_set_root_generation_v2(new_root_item, 1363 trans->transid); 1364 uuid_le_gen(&new_uuid); 1365 memcpy(new_root_item->uuid, new_uuid.b, BTRFS_UUID_SIZE); 1366 memcpy(new_root_item->parent_uuid, root->root_item.uuid, 1367 BTRFS_UUID_SIZE); 1368 if (!(root_flags & BTRFS_ROOT_SUBVOL_RDONLY)) { 1369 memset(new_root_item->received_uuid, 0, 1370 sizeof(new_root_item->received_uuid)); 1371 memset(&new_root_item->stime, 0, sizeof(new_root_item->stime)); 1372 memset(&new_root_item->rtime, 0, sizeof(new_root_item->rtime)); 1373 btrfs_set_root_stransid(new_root_item, 0); 1374 btrfs_set_root_rtransid(new_root_item, 0); 1375 } 1376 btrfs_set_stack_timespec_sec(&new_root_item->otime, cur_time.tv_sec); 1377 btrfs_set_stack_timespec_nsec(&new_root_item->otime, cur_time.tv_nsec); 1378 btrfs_set_root_otransid(new_root_item, trans->transid); 1379 1380 old = btrfs_lock_root_node(root); 1381 ret = btrfs_cow_block(trans, root, old, NULL, 0, &old); 1382 if (ret) { 1383 btrfs_tree_unlock(old); 1384 free_extent_buffer(old); 1385 btrfs_abort_transaction(trans, root, ret); 1386 goto fail; 1387 } 1388 1389 btrfs_set_lock_blocking(old); 1390 1391 ret = btrfs_copy_root(trans, root, old, &tmp, objectid); 1392 /* clean up in any case */ 1393 btrfs_tree_unlock(old); 1394 free_extent_buffer(old); 1395 if (ret) { 1396 btrfs_abort_transaction(trans, root, ret); 1397 goto fail; 1398 } 1399 1400 /* 1401 * We need to flush delayed refs in order to make sure all of our quota 1402 * operations have been done before we call btrfs_qgroup_inherit. 1403 */ 1404 ret = btrfs_run_delayed_refs(trans, root, (unsigned long)-1); 1405 if (ret) { 1406 btrfs_abort_transaction(trans, root, ret); 1407 goto fail; 1408 } 1409 1410 ret = btrfs_qgroup_inherit(trans, fs_info, 1411 root->root_key.objectid, 1412 objectid, pending->inherit); 1413 if (ret) { 1414 btrfs_abort_transaction(trans, root, ret); 1415 goto fail; 1416 } 1417 1418 /* see comments in should_cow_block() */ 1419 set_bit(BTRFS_ROOT_FORCE_COW, &root->state); 1420 smp_wmb(); 1421 1422 btrfs_set_root_node(new_root_item, tmp); 1423 /* record when the snapshot was created in key.offset */ 1424 key.offset = trans->transid; 1425 ret = btrfs_insert_root(trans, tree_root, &key, new_root_item); 1426 btrfs_tree_unlock(tmp); 1427 free_extent_buffer(tmp); 1428 if (ret) { 1429 btrfs_abort_transaction(trans, root, ret); 1430 goto fail; 1431 } 1432 1433 /* 1434 * insert root back/forward references 1435 */ 1436 ret = btrfs_add_root_ref(trans, tree_root, objectid, 1437 parent_root->root_key.objectid, 1438 btrfs_ino(parent_inode), index, 1439 dentry->d_name.name, dentry->d_name.len); 1440 if (ret) { 1441 btrfs_abort_transaction(trans, root, ret); 1442 goto fail; 1443 } 1444 1445 key.offset = (u64)-1; 1446 pending->snap = btrfs_read_fs_root_no_name(root->fs_info, &key); 1447 if (IS_ERR(pending->snap)) { 1448 ret = PTR_ERR(pending->snap); 1449 btrfs_abort_transaction(trans, root, ret); 1450 goto fail; 1451 } 1452 1453 ret = btrfs_reloc_post_snapshot(trans, pending); 1454 if (ret) { 1455 btrfs_abort_transaction(trans, root, ret); 1456 goto fail; 1457 } 1458 1459 ret = btrfs_run_delayed_refs(trans, root, (unsigned long)-1); 1460 if (ret) { 1461 btrfs_abort_transaction(trans, root, ret); 1462 goto fail; 1463 } 1464 1465 ret = btrfs_insert_dir_item(trans, parent_root, 1466 dentry->d_name.name, dentry->d_name.len, 1467 parent_inode, &key, 1468 BTRFS_FT_DIR, index); 1469 /* We have check then name at the beginning, so it is impossible. */ 1470 BUG_ON(ret == -EEXIST || ret == -EOVERFLOW); 1471 if (ret) { 1472 btrfs_abort_transaction(trans, root, ret); 1473 goto fail; 1474 } 1475 1476 btrfs_i_size_write(parent_inode, parent_inode->i_size + 1477 dentry->d_name.len * 2); 1478 parent_inode->i_mtime = parent_inode->i_ctime = CURRENT_TIME; 1479 ret = btrfs_update_inode_fallback(trans, parent_root, parent_inode); 1480 if (ret) { 1481 btrfs_abort_transaction(trans, root, ret); 1482 goto fail; 1483 } 1484 ret = btrfs_uuid_tree_add(trans, fs_info->uuid_root, new_uuid.b, 1485 BTRFS_UUID_KEY_SUBVOL, objectid); 1486 if (ret) { 1487 btrfs_abort_transaction(trans, root, ret); 1488 goto fail; 1489 } 1490 if (!btrfs_is_empty_uuid(new_root_item->received_uuid)) { 1491 ret = btrfs_uuid_tree_add(trans, fs_info->uuid_root, 1492 new_root_item->received_uuid, 1493 BTRFS_UUID_KEY_RECEIVED_SUBVOL, 1494 objectid); 1495 if (ret && ret != -EEXIST) { 1496 btrfs_abort_transaction(trans, root, ret); 1497 goto fail; 1498 } 1499 } 1500fail: 1501 pending->error = ret; 1502dir_item_existed: 1503 trans->block_rsv = rsv; 1504 trans->bytes_reserved = 0; 1505no_free_objectid: 1506 kfree(new_root_item); 1507root_item_alloc_fail: 1508 btrfs_free_path(path); 1509 return ret; 1510} 1511 1512/* 1513 * create all the snapshots we've scheduled for creation 1514 */ 1515static noinline int create_pending_snapshots(struct btrfs_trans_handle *trans, 1516 struct btrfs_fs_info *fs_info) 1517{ 1518 struct btrfs_pending_snapshot *pending, *next; 1519 struct list_head *head = &trans->transaction->pending_snapshots; 1520 int ret = 0; 1521 1522 list_for_each_entry_safe(pending, next, head, list) { 1523 list_del(&pending->list); 1524 ret = create_pending_snapshot(trans, fs_info, pending); 1525 if (ret) 1526 break; 1527 } 1528 return ret; 1529} 1530 1531static void update_super_roots(struct btrfs_root *root) 1532{ 1533 struct btrfs_root_item *root_item; 1534 struct btrfs_super_block *super; 1535 1536 super = root->fs_info->super_copy; 1537 1538 root_item = &root->fs_info->chunk_root->root_item; 1539 super->chunk_root = root_item->bytenr; 1540 super->chunk_root_generation = root_item->generation; 1541 super->chunk_root_level = root_item->level; 1542 1543 root_item = &root->fs_info->tree_root->root_item; 1544 super->root = root_item->bytenr; 1545 super->generation = root_item->generation; 1546 super->root_level = root_item->level; 1547 if (btrfs_test_opt(root, SPACE_CACHE)) 1548 super->cache_generation = root_item->generation; 1549 if (root->fs_info->update_uuid_tree_gen) 1550 super->uuid_tree_generation = root_item->generation; 1551} 1552 1553int btrfs_transaction_in_commit(struct btrfs_fs_info *info) 1554{ 1555 struct btrfs_transaction *trans; 1556 int ret = 0; 1557 1558 spin_lock(&info->trans_lock); 1559 trans = info->running_transaction; 1560 if (trans) 1561 ret = (trans->state >= TRANS_STATE_COMMIT_START); 1562 spin_unlock(&info->trans_lock); 1563 return ret; 1564} 1565 1566int btrfs_transaction_blocked(struct btrfs_fs_info *info) 1567{ 1568 struct btrfs_transaction *trans; 1569 int ret = 0; 1570 1571 spin_lock(&info->trans_lock); 1572 trans = info->running_transaction; 1573 if (trans) 1574 ret = is_transaction_blocked(trans); 1575 spin_unlock(&info->trans_lock); 1576 return ret; 1577} 1578 1579/* 1580 * wait for the current transaction commit to start and block subsequent 1581 * transaction joins 1582 */ 1583static void wait_current_trans_commit_start(struct btrfs_root *root, 1584 struct btrfs_transaction *trans) 1585{ 1586 wait_event(root->fs_info->transaction_blocked_wait, 1587 trans->state >= TRANS_STATE_COMMIT_START || 1588 trans->aborted); 1589} 1590 1591/* 1592 * wait for the current transaction to start and then become unblocked. 1593 * caller holds ref. 1594 */ 1595static void wait_current_trans_commit_start_and_unblock(struct btrfs_root *root, 1596 struct btrfs_transaction *trans) 1597{ 1598 wait_event(root->fs_info->transaction_wait, 1599 trans->state >= TRANS_STATE_UNBLOCKED || 1600 trans->aborted); 1601} 1602 1603/* 1604 * commit transactions asynchronously. once btrfs_commit_transaction_async 1605 * returns, any subsequent transaction will not be allowed to join. 1606 */ 1607struct btrfs_async_commit { 1608 struct btrfs_trans_handle *newtrans; 1609 struct btrfs_root *root; 1610 struct work_struct work; 1611}; 1612 1613static void do_async_commit(struct work_struct *work) 1614{ 1615 struct btrfs_async_commit *ac = 1616 container_of(work, struct btrfs_async_commit, work); 1617 1618 /* 1619 * We've got freeze protection passed with the transaction. 1620 * Tell lockdep about it. 1621 */ 1622 if (ac->newtrans->type & __TRANS_FREEZABLE) 1623 rwsem_acquire_read( 1624 &ac->root->fs_info->sb->s_writers.lock_map[SB_FREEZE_FS-1], 1625 0, 1, _THIS_IP_); 1626 1627 current->journal_info = ac->newtrans; 1628 1629 btrfs_commit_transaction(ac->newtrans, ac->root); 1630 kfree(ac); 1631} 1632 1633int btrfs_commit_transaction_async(struct btrfs_trans_handle *trans, 1634 struct btrfs_root *root, 1635 int wait_for_unblock) 1636{ 1637 struct btrfs_async_commit *ac; 1638 struct btrfs_transaction *cur_trans; 1639 1640 ac = kmalloc(sizeof(*ac), GFP_NOFS); 1641 if (!ac) 1642 return -ENOMEM; 1643 1644 INIT_WORK(&ac->work, do_async_commit); 1645 ac->root = root; 1646 ac->newtrans = btrfs_join_transaction(root); 1647 if (IS_ERR(ac->newtrans)) { 1648 int err = PTR_ERR(ac->newtrans); 1649 kfree(ac); 1650 return err; 1651 } 1652 1653 /* take transaction reference */ 1654 cur_trans = trans->transaction; 1655 atomic_inc(&cur_trans->use_count); 1656 1657 btrfs_end_transaction(trans, root); 1658 1659 /* 1660 * Tell lockdep we've released the freeze rwsem, since the 1661 * async commit thread will be the one to unlock it. 1662 */ 1663 if (ac->newtrans->type & __TRANS_FREEZABLE) 1664 rwsem_release( 1665 &root->fs_info->sb->s_writers.lock_map[SB_FREEZE_FS-1], 1666 1, _THIS_IP_); 1667 1668 schedule_work(&ac->work); 1669 1670 /* wait for transaction to start and unblock */ 1671 if (wait_for_unblock) 1672 wait_current_trans_commit_start_and_unblock(root, cur_trans); 1673 else 1674 wait_current_trans_commit_start(root, cur_trans); 1675 1676 if (current->journal_info == trans) 1677 current->journal_info = NULL; 1678 1679 btrfs_put_transaction(cur_trans); 1680 return 0; 1681} 1682 1683 1684static void cleanup_transaction(struct btrfs_trans_handle *trans, 1685 struct btrfs_root *root, int err) 1686{ 1687 struct btrfs_transaction *cur_trans = trans->transaction; 1688 DEFINE_WAIT(wait); 1689 1690 WARN_ON(trans->use_count > 1); 1691 1692 btrfs_abort_transaction(trans, root, err); 1693 1694 spin_lock(&root->fs_info->trans_lock); 1695 1696 /* 1697 * If the transaction is removed from the list, it means this 1698 * transaction has been committed successfully, so it is impossible 1699 * to call the cleanup function. 1700 */ 1701 BUG_ON(list_empty(&cur_trans->list)); 1702 1703 list_del_init(&cur_trans->list); 1704 if (cur_trans == root->fs_info->running_transaction) { 1705 cur_trans->state = TRANS_STATE_COMMIT_DOING; 1706 spin_unlock(&root->fs_info->trans_lock); 1707 wait_event(cur_trans->writer_wait, 1708 atomic_read(&cur_trans->num_writers) == 1); 1709 1710 spin_lock(&root->fs_info->trans_lock); 1711 } 1712 spin_unlock(&root->fs_info->trans_lock); 1713 1714 btrfs_cleanup_one_transaction(trans->transaction, root); 1715 1716 spin_lock(&root->fs_info->trans_lock); 1717 if (cur_trans == root->fs_info->running_transaction) 1718 root->fs_info->running_transaction = NULL; 1719 spin_unlock(&root->fs_info->trans_lock); 1720 1721 if (trans->type & __TRANS_FREEZABLE) 1722 sb_end_intwrite(root->fs_info->sb); 1723 btrfs_put_transaction(cur_trans); 1724 btrfs_put_transaction(cur_trans); 1725 1726 trace_btrfs_transaction_commit(root); 1727 1728 if (current->journal_info == trans) 1729 current->journal_info = NULL; 1730 btrfs_scrub_cancel(root->fs_info); 1731 1732 kmem_cache_free(btrfs_trans_handle_cachep, trans); 1733} 1734 1735static inline int btrfs_start_delalloc_flush(struct btrfs_fs_info *fs_info) 1736{ 1737 if (btrfs_test_opt(fs_info->tree_root, FLUSHONCOMMIT)) 1738 return btrfs_start_delalloc_roots(fs_info, 1, -1); 1739 return 0; 1740} 1741 1742static inline void btrfs_wait_delalloc_flush(struct btrfs_fs_info *fs_info) 1743{ 1744 if (btrfs_test_opt(fs_info->tree_root, FLUSHONCOMMIT)) 1745 btrfs_wait_ordered_roots(fs_info, -1); 1746} 1747 1748static inline void 1749btrfs_wait_pending_ordered(struct btrfs_transaction *cur_trans, 1750 struct btrfs_fs_info *fs_info) 1751{ 1752 struct btrfs_ordered_extent *ordered; 1753 1754 spin_lock(&fs_info->trans_lock); 1755 while (!list_empty(&cur_trans->pending_ordered)) { 1756 ordered = list_first_entry(&cur_trans->pending_ordered, 1757 struct btrfs_ordered_extent, 1758 trans_list); 1759 list_del_init(&ordered->trans_list); 1760 spin_unlock(&fs_info->trans_lock); 1761 1762 wait_event(ordered->wait, test_bit(BTRFS_ORDERED_COMPLETE, 1763 &ordered->flags)); 1764 btrfs_put_ordered_extent(ordered); 1765 spin_lock(&fs_info->trans_lock); 1766 } 1767 spin_unlock(&fs_info->trans_lock); 1768} 1769 1770int btrfs_commit_transaction(struct btrfs_trans_handle *trans, 1771 struct btrfs_root *root) 1772{ 1773 struct btrfs_transaction *cur_trans = trans->transaction; 1774 struct btrfs_transaction *prev_trans = NULL; 1775 struct btrfs_inode *btree_ino = BTRFS_I(root->fs_info->btree_inode); 1776 int ret; 1777 1778 /* Stop the commit early if ->aborted is set */ 1779 if (unlikely(ACCESS_ONCE(cur_trans->aborted))) { 1780 ret = cur_trans->aborted; 1781 btrfs_end_transaction(trans, root); 1782 return ret; 1783 } 1784 1785 /* make a pass through all the delayed refs we have so far 1786 * any runnings procs may add more while we are here 1787 */ 1788 ret = btrfs_run_delayed_refs(trans, root, 0); 1789 if (ret) { 1790 btrfs_end_transaction(trans, root); 1791 return ret; 1792 } 1793 1794 btrfs_trans_release_metadata(trans, root); 1795 trans->block_rsv = NULL; 1796 if (trans->qgroup_reserved) { 1797 btrfs_qgroup_free(root, trans->qgroup_reserved); 1798 trans->qgroup_reserved = 0; 1799 } 1800 1801 cur_trans = trans->transaction; 1802 1803 /* 1804 * set the flushing flag so procs in this transaction have to 1805 * start sending their work down. 1806 */ 1807 cur_trans->delayed_refs.flushing = 1; 1808 smp_wmb(); 1809 1810 if (!list_empty(&trans->new_bgs)) 1811 btrfs_create_pending_block_groups(trans, root); 1812 1813 ret = btrfs_run_delayed_refs(trans, root, 0); 1814 if (ret) { 1815 btrfs_end_transaction(trans, root); 1816 return ret; 1817 } 1818 1819 if (!cur_trans->dirty_bg_run) { 1820 int run_it = 0; 1821 1822 /* this mutex is also taken before trying to set 1823 * block groups readonly. We need to make sure 1824 * that nobody has set a block group readonly 1825 * after a extents from that block group have been 1826 * allocated for cache files. btrfs_set_block_group_ro 1827 * will wait for the transaction to commit if it 1828 * finds dirty_bg_run = 1 1829 * 1830 * The dirty_bg_run flag is also used to make sure only 1831 * one process starts all the block group IO. It wouldn't 1832 * hurt to have more than one go through, but there's no 1833 * real advantage to it either. 1834 */ 1835 mutex_lock(&root->fs_info->ro_block_group_mutex); 1836 if (!cur_trans->dirty_bg_run) { 1837 run_it = 1; 1838 cur_trans->dirty_bg_run = 1; 1839 } 1840 mutex_unlock(&root->fs_info->ro_block_group_mutex); 1841 1842 if (run_it) 1843 ret = btrfs_start_dirty_block_groups(trans, root); 1844 } 1845 if (ret) { 1846 btrfs_end_transaction(trans, root); 1847 return ret; 1848 } 1849 1850 spin_lock(&root->fs_info->trans_lock); 1851 list_splice_init(&trans->ordered, &cur_trans->pending_ordered); 1852 if (cur_trans->state >= TRANS_STATE_COMMIT_START) { 1853 spin_unlock(&root->fs_info->trans_lock); 1854 atomic_inc(&cur_trans->use_count); 1855 ret = btrfs_end_transaction(trans, root); 1856 1857 wait_for_commit(root, cur_trans); 1858 1859 if (unlikely(cur_trans->aborted)) 1860 ret = cur_trans->aborted; 1861 1862 btrfs_put_transaction(cur_trans); 1863 1864 return ret; 1865 } 1866 1867 cur_trans->state = TRANS_STATE_COMMIT_START; 1868 wake_up(&root->fs_info->transaction_blocked_wait); 1869 1870 if (cur_trans->list.prev != &root->fs_info->trans_list) { 1871 prev_trans = list_entry(cur_trans->list.prev, 1872 struct btrfs_transaction, list); 1873 if (prev_trans->state != TRANS_STATE_COMPLETED) { 1874 atomic_inc(&prev_trans->use_count); 1875 spin_unlock(&root->fs_info->trans_lock); 1876 1877 wait_for_commit(root, prev_trans); 1878 ret = prev_trans->aborted; 1879 1880 btrfs_put_transaction(prev_trans); 1881 if (ret) 1882 goto cleanup_transaction; 1883 } else { 1884 spin_unlock(&root->fs_info->trans_lock); 1885 } 1886 } else { 1887 spin_unlock(&root->fs_info->trans_lock); 1888 } 1889 1890 extwriter_counter_dec(cur_trans, trans->type); 1891 1892 ret = btrfs_start_delalloc_flush(root->fs_info); 1893 if (ret) 1894 goto cleanup_transaction; 1895 1896 ret = btrfs_run_delayed_items(trans, root); 1897 if (ret) 1898 goto cleanup_transaction; 1899 1900 wait_event(cur_trans->writer_wait, 1901 extwriter_counter_read(cur_trans) == 0); 1902 1903 /* some pending stuffs might be added after the previous flush. */ 1904 ret = btrfs_run_delayed_items(trans, root); 1905 if (ret) 1906 goto cleanup_transaction; 1907 1908 btrfs_wait_delalloc_flush(root->fs_info); 1909 1910 btrfs_wait_pending_ordered(cur_trans, root->fs_info); 1911 1912 btrfs_scrub_pause(root); 1913 /* 1914 * Ok now we need to make sure to block out any other joins while we 1915 * commit the transaction. We could have started a join before setting 1916 * COMMIT_DOING so make sure to wait for num_writers to == 1 again. 1917 */ 1918 spin_lock(&root->fs_info->trans_lock); 1919 cur_trans->state = TRANS_STATE_COMMIT_DOING; 1920 spin_unlock(&root->fs_info->trans_lock); 1921 wait_event(cur_trans->writer_wait, 1922 atomic_read(&cur_trans->num_writers) == 1); 1923 1924 /* ->aborted might be set after the previous check, so check it */ 1925 if (unlikely(ACCESS_ONCE(cur_trans->aborted))) { 1926 ret = cur_trans->aborted; 1927 goto scrub_continue; 1928 } 1929 /* 1930 * the reloc mutex makes sure that we stop 1931 * the balancing code from coming in and moving 1932 * extents around in the middle of the commit 1933 */ 1934 mutex_lock(&root->fs_info->reloc_mutex); 1935 1936 /* 1937 * We needn't worry about the delayed items because we will 1938 * deal with them in create_pending_snapshot(), which is the 1939 * core function of the snapshot creation. 1940 */ 1941 ret = create_pending_snapshots(trans, root->fs_info); 1942 if (ret) { 1943 mutex_unlock(&root->fs_info->reloc_mutex); 1944 goto scrub_continue; 1945 } 1946 1947 /* 1948 * We insert the dir indexes of the snapshots and update the inode 1949 * of the snapshots' parents after the snapshot creation, so there 1950 * are some delayed items which are not dealt with. Now deal with 1951 * them. 1952 * 1953 * We needn't worry that this operation will corrupt the snapshots, 1954 * because all the tree which are snapshoted will be forced to COW 1955 * the nodes and leaves. 1956 */ 1957 ret = btrfs_run_delayed_items(trans, root); 1958 if (ret) { 1959 mutex_unlock(&root->fs_info->reloc_mutex); 1960 goto scrub_continue; 1961 } 1962 1963 ret = btrfs_run_delayed_refs(trans, root, (unsigned long)-1); 1964 if (ret) { 1965 mutex_unlock(&root->fs_info->reloc_mutex); 1966 goto scrub_continue; 1967 } 1968 1969 /* 1970 * make sure none of the code above managed to slip in a 1971 * delayed item 1972 */ 1973 btrfs_assert_delayed_root_empty(root); 1974 1975 WARN_ON(cur_trans != trans->transaction); 1976 1977 /* btrfs_commit_tree_roots is responsible for getting the 1978 * various roots consistent with each other. Every pointer 1979 * in the tree of tree roots has to point to the most up to date 1980 * root for every subvolume and other tree. So, we have to keep 1981 * the tree logging code from jumping in and changing any 1982 * of the trees. 1983 * 1984 * At this point in the commit, there can't be any tree-log 1985 * writers, but a little lower down we drop the trans mutex 1986 * and let new people in. By holding the tree_log_mutex 1987 * from now until after the super is written, we avoid races 1988 * with the tree-log code. 1989 */ 1990 mutex_lock(&root->fs_info->tree_log_mutex); 1991 1992 ret = commit_fs_roots(trans, root); 1993 if (ret) { 1994 mutex_unlock(&root->fs_info->tree_log_mutex); 1995 mutex_unlock(&root->fs_info->reloc_mutex); 1996 goto scrub_continue; 1997 } 1998 1999 /* 2000 * Since the transaction is done, we can apply the pending changes 2001 * before the next transaction. 2002 */ 2003 btrfs_apply_pending_changes(root->fs_info); 2004 2005 /* commit_fs_roots gets rid of all the tree log roots, it is now 2006 * safe to free the root of tree log roots 2007 */ 2008 btrfs_free_log_root_tree(trans, root->fs_info); 2009 2010 ret = commit_cowonly_roots(trans, root); 2011 if (ret) { 2012 mutex_unlock(&root->fs_info->tree_log_mutex); 2013 mutex_unlock(&root->fs_info->reloc_mutex); 2014 goto scrub_continue; 2015 } 2016 2017 /* 2018 * The tasks which save the space cache and inode cache may also 2019 * update ->aborted, check it. 2020 */ 2021 if (unlikely(ACCESS_ONCE(cur_trans->aborted))) { 2022 ret = cur_trans->aborted; 2023 mutex_unlock(&root->fs_info->tree_log_mutex); 2024 mutex_unlock(&root->fs_info->reloc_mutex); 2025 goto scrub_continue; 2026 } 2027 2028 btrfs_prepare_extent_commit(trans, root); 2029 2030 cur_trans = root->fs_info->running_transaction; 2031 2032 btrfs_set_root_node(&root->fs_info->tree_root->root_item, 2033 root->fs_info->tree_root->node); 2034 list_add_tail(&root->fs_info->tree_root->dirty_list, 2035 &cur_trans->switch_commits); 2036 2037 btrfs_set_root_node(&root->fs_info->chunk_root->root_item, 2038 root->fs_info->chunk_root->node); 2039 list_add_tail(&root->fs_info->chunk_root->dirty_list, 2040 &cur_trans->switch_commits); 2041 2042 switch_commit_roots(cur_trans, root->fs_info); 2043 2044 assert_qgroups_uptodate(trans); 2045 ASSERT(list_empty(&cur_trans->dirty_bgs)); 2046 ASSERT(list_empty(&cur_trans->io_bgs)); 2047 update_super_roots(root); 2048 2049 btrfs_set_super_log_root(root->fs_info->super_copy, 0); 2050 btrfs_set_super_log_root_level(root->fs_info->super_copy, 0); 2051 memcpy(root->fs_info->super_for_commit, root->fs_info->super_copy, 2052 sizeof(*root->fs_info->super_copy)); 2053 2054 btrfs_update_commit_device_size(root->fs_info); 2055 btrfs_update_commit_device_bytes_used(root, cur_trans); 2056 2057 clear_bit(BTRFS_INODE_BTREE_LOG1_ERR, &btree_ino->runtime_flags); 2058 clear_bit(BTRFS_INODE_BTREE_LOG2_ERR, &btree_ino->runtime_flags); 2059 2060 spin_lock(&root->fs_info->trans_lock); 2061 cur_trans->state = TRANS_STATE_UNBLOCKED; 2062 root->fs_info->running_transaction = NULL; 2063 spin_unlock(&root->fs_info->trans_lock); 2064 mutex_unlock(&root->fs_info->reloc_mutex); 2065 2066 wake_up(&root->fs_info->transaction_wait); 2067 2068 ret = btrfs_write_and_wait_transaction(trans, root); 2069 if (ret) { 2070 btrfs_error(root->fs_info, ret, 2071 "Error while writing out transaction"); 2072 mutex_unlock(&root->fs_info->tree_log_mutex); 2073 goto scrub_continue; 2074 } 2075 2076 ret = write_ctree_super(trans, root, 0); 2077 if (ret) { 2078 mutex_unlock(&root->fs_info->tree_log_mutex); 2079 goto scrub_continue; 2080 } 2081 2082 /* 2083 * the super is written, we can safely allow the tree-loggers 2084 * to go about their business 2085 */ 2086 mutex_unlock(&root->fs_info->tree_log_mutex); 2087 2088 btrfs_finish_extent_commit(trans, root); 2089 2090 if (cur_trans->have_free_bgs) 2091 btrfs_clear_space_info_full(root->fs_info); 2092 2093 root->fs_info->last_trans_committed = cur_trans->transid; 2094 /* 2095 * We needn't acquire the lock here because there is no other task 2096 * which can change it. 2097 */ 2098 cur_trans->state = TRANS_STATE_COMPLETED; 2099 wake_up(&cur_trans->commit_wait); 2100 2101 spin_lock(&root->fs_info->trans_lock); 2102 list_del_init(&cur_trans->list); 2103 spin_unlock(&root->fs_info->trans_lock); 2104 2105 btrfs_put_transaction(cur_trans); 2106 btrfs_put_transaction(cur_trans); 2107 2108 if (trans->type & __TRANS_FREEZABLE) 2109 sb_end_intwrite(root->fs_info->sb); 2110 2111 trace_btrfs_transaction_commit(root); 2112 2113 btrfs_scrub_continue(root); 2114 2115 if (current->journal_info == trans) 2116 current->journal_info = NULL; 2117 2118 kmem_cache_free(btrfs_trans_handle_cachep, trans); 2119 2120 if (current != root->fs_info->transaction_kthread) 2121 btrfs_run_delayed_iputs(root); 2122 2123 return ret; 2124 2125scrub_continue: 2126 btrfs_scrub_continue(root); 2127cleanup_transaction: 2128 btrfs_trans_release_metadata(trans, root); 2129 trans->block_rsv = NULL; 2130 if (trans->qgroup_reserved) { 2131 btrfs_qgroup_free(root, trans->qgroup_reserved); 2132 trans->qgroup_reserved = 0; 2133 } 2134 btrfs_warn(root->fs_info, "Skipping commit of aborted transaction."); 2135 if (current->journal_info == trans) 2136 current->journal_info = NULL; 2137 cleanup_transaction(trans, root, ret); 2138 2139 return ret; 2140} 2141 2142/* 2143 * return < 0 if error 2144 * 0 if there are no more dead_roots at the time of call 2145 * 1 there are more to be processed, call me again 2146 * 2147 * The return value indicates there are certainly more snapshots to delete, but 2148 * if there comes a new one during processing, it may return 0. We don't mind, 2149 * because btrfs_commit_super will poke cleaner thread and it will process it a 2150 * few seconds later. 2151 */ 2152int btrfs_clean_one_deleted_snapshot(struct btrfs_root *root) 2153{ 2154 int ret; 2155 struct btrfs_fs_info *fs_info = root->fs_info; 2156 2157 spin_lock(&fs_info->trans_lock); 2158 if (list_empty(&fs_info->dead_roots)) { 2159 spin_unlock(&fs_info->trans_lock); 2160 return 0; 2161 } 2162 root = list_first_entry(&fs_info->dead_roots, 2163 struct btrfs_root, root_list); 2164 list_del_init(&root->root_list); 2165 spin_unlock(&fs_info->trans_lock); 2166 2167 pr_debug("BTRFS: cleaner removing %llu\n", root->objectid); 2168 2169 btrfs_kill_all_delayed_nodes(root); 2170 2171 if (btrfs_header_backref_rev(root->node) < 2172 BTRFS_MIXED_BACKREF_REV) 2173 ret = btrfs_drop_snapshot(root, NULL, 0, 0); 2174 else 2175 ret = btrfs_drop_snapshot(root, NULL, 1, 0); 2176 2177 return (ret < 0) ? 0 : 1; 2178} 2179 2180void btrfs_apply_pending_changes(struct btrfs_fs_info *fs_info) 2181{ 2182 unsigned long prev; 2183 unsigned long bit; 2184 2185 prev = xchg(&fs_info->pending_changes, 0); 2186 if (!prev) 2187 return; 2188 2189 bit = 1 << BTRFS_PENDING_SET_INODE_MAP_CACHE; 2190 if (prev & bit) 2191 btrfs_set_opt(fs_info->mount_opt, INODE_MAP_CACHE); 2192 prev &= ~bit; 2193 2194 bit = 1 << BTRFS_PENDING_CLEAR_INODE_MAP_CACHE; 2195 if (prev & bit) 2196 btrfs_clear_opt(fs_info->mount_opt, INODE_MAP_CACHE); 2197 prev &= ~bit; 2198 2199 bit = 1 << BTRFS_PENDING_COMMIT; 2200 if (prev & bit) 2201 btrfs_debug(fs_info, "pending commit done"); 2202 prev &= ~bit; 2203 2204 if (prev) 2205 btrfs_warn(fs_info, 2206 "unknown pending changes left 0x%lx, ignoring", prev); 2207} 2208