1// SPDX-License-Identifier: GPL-2.0
   2/*
   3 * Copyright (C) 2007 Oracle.  All rights reserved.
 
 
 
 
 
 
 
 
 
 
 
 
 
 
   4 */
   5
   6#include <linux/fs.h>
   7#include <linux/slab.h>
   8#include <linux/sched.h>
   9#include <linux/sched/mm.h>
  10#include <linux/writeback.h>
  11#include <linux/pagemap.h>
  12#include <linux/blkdev.h>
  13#include <linux/uuid.h>
  14#include <linux/timekeeping.h>
  15#include "misc.h"
  16#include "ctree.h"
  17#include "disk-io.h"
  18#include "transaction.h"
  19#include "locking.h"
  20#include "tree-log.h"
 
  21#include "volumes.h"
  22#include "dev-replace.h"
  23#include "qgroup.h"
  24#include "block-group.h"
  25#include "space-info.h"
  26#include "fs.h"
  27#include "accessors.h"
  28#include "extent-tree.h"
  29#include "root-tree.h"
  30#include "dir-item.h"
  31#include "uuid-tree.h"
  32#include "ioctl.h"
  33#include "relocation.h"
  34#include "scrub.h"
  35
  36static struct kmem_cache *btrfs_trans_handle_cachep;
  37
  38/*
  39 * Transaction states and transitions
  40 *
  41 * No running transaction (fs tree blocks are not modified)
  42 * |
  43 * | To next stage:
  44 * |  Call start_transaction() variants. Except btrfs_join_transaction_nostart().
  45 * V
  46 * Transaction N [[TRANS_STATE_RUNNING]]
  47 * |
  48 * | New trans handles can be attached to transaction N by calling all
  49 * | start_transaction() variants.
  50 * |
  51 * | To next stage:
  52 * |  Call btrfs_commit_transaction() on any trans handle attached to
  53 * |  transaction N
  54 * V
  55 * Transaction N [[TRANS_STATE_COMMIT_PREP]]
  56 * |
  57 * | If there are simultaneous calls to btrfs_commit_transaction() one will win
  58 * | the race and the rest will wait for the winner to commit the transaction.
  59 * |
  60 * | The winner will wait for previous running transaction to completely finish
  61 * | if there is one.
  62 * |
  63 * Transaction N [[TRANS_STATE_COMMIT_START]]
  64 * |
  65 * | Then one of the following happens:
  66 * | - Wait for all other trans handle holders to release.
  67 * |   The btrfs_commit_transaction() caller will do the commit work.
  68 * | - Wait for current transaction to be committed by others.
  69 * |   Other btrfs_commit_transaction() caller will do the commit work.
  70 * |
  71 * | At this stage, only btrfs_join_transaction*() variants can attach
  72 * | to this running transaction.
  73 * | All other variants will wait for current one to finish and attach to
  74 * | transaction N+1.
  75 * |
  76 * | To next stage:
  77 * |  Caller is chosen to commit transaction N, and all other trans handle
  78 * |  haven been released.
  79 * V
  80 * Transaction N [[TRANS_STATE_COMMIT_DOING]]
  81 * |
  82 * | The heavy lifting transaction work is started.
  83 * | From running delayed refs (modifying extent tree) to creating pending
  84 * | snapshots, running qgroups.
  85 * | In short, modify supporting trees to reflect modifications of subvolume
  86 * | trees.
  87 * |
  88 * | At this stage, all start_transaction() calls will wait for this
  89 * | transaction to finish and attach to transaction N+1.
  90 * |
  91 * | To next stage:
  92 * |  Until all supporting trees are updated.
  93 * V
  94 * Transaction N [[TRANS_STATE_UNBLOCKED]]
  95 * |						    Transaction N+1
  96 * | All needed trees are modified, thus we only    [[TRANS_STATE_RUNNING]]
  97 * | need to write them back to disk and update	    |
  98 * | super blocks.				    |
  99 * |						    |
 100 * | At this stage, new transaction is allowed to   |
 101 * | start.					    |
 102 * | All new start_transaction() calls will be	    |
 103 * | attached to transid N+1.			    |
 104 * |						    |
 105 * | To next stage:				    |
 106 * |  Until all tree blocks are super blocks are    |
 107 * |  written to block devices			    |
 108 * V						    |
 109 * Transaction N [[TRANS_STATE_COMPLETED]]	    V
 110 *   All tree blocks and super blocks are written.  Transaction N+1
 111 *   This transaction is finished and all its	    [[TRANS_STATE_COMMIT_START]]
 112 *   data structures will be cleaned up.	    | Life goes on
 113 */
 114static const unsigned int btrfs_blocked_trans_types[TRANS_STATE_MAX] = {
 115	[TRANS_STATE_RUNNING]		= 0U,
 116	[TRANS_STATE_COMMIT_PREP]	= 0U,
 117	[TRANS_STATE_COMMIT_START]	= (__TRANS_START | __TRANS_ATTACH),
 118	[TRANS_STATE_COMMIT_DOING]	= (__TRANS_START |
 119					   __TRANS_ATTACH |
 120					   __TRANS_JOIN |
 121					   __TRANS_JOIN_NOSTART),
 122	[TRANS_STATE_UNBLOCKED]		= (__TRANS_START |
 123					   __TRANS_ATTACH |
 124					   __TRANS_JOIN |
 125					   __TRANS_JOIN_NOLOCK |
 126					   __TRANS_JOIN_NOSTART),
 127	[TRANS_STATE_SUPER_COMMITTED]	= (__TRANS_START |
 128					   __TRANS_ATTACH |
 129					   __TRANS_JOIN |
 130					   __TRANS_JOIN_NOLOCK |
 131					   __TRANS_JOIN_NOSTART),
 132	[TRANS_STATE_COMPLETED]		= (__TRANS_START |
 133					   __TRANS_ATTACH |
 134					   __TRANS_JOIN |
 135					   __TRANS_JOIN_NOLOCK |
 136					   __TRANS_JOIN_NOSTART),
 137};
 138
 139void btrfs_put_transaction(struct btrfs_transaction *transaction)
 140{
 141	WARN_ON(refcount_read(&transaction->use_count) == 0);
 142	if (refcount_dec_and_test(&transaction->use_count)) {
 143		BUG_ON(!list_empty(&transaction->list));
 144		WARN_ON(!xa_empty(&transaction->delayed_refs.head_refs));
 145		WARN_ON(!xa_empty(&transaction->delayed_refs.dirty_extents));
 146		if (transaction->delayed_refs.pending_csums)
 147			btrfs_err(transaction->fs_info,
 148				  "pending csums is %llu",
 149				  transaction->delayed_refs.pending_csums);
 
 
 
 
 
 
 
 
 150		/*
 151		 * If any block groups are found in ->deleted_bgs then it's
 152		 * because the transaction was aborted and a commit did not
 153		 * happen (things failed before writing the new superblock
 154		 * and calling btrfs_finish_extent_commit()), so we can not
 155		 * discard the physical locations of the block groups.
 156		 */
 157		while (!list_empty(&transaction->deleted_bgs)) {
 158			struct btrfs_block_group *cache;
 159
 160			cache = list_first_entry(&transaction->deleted_bgs,
 161						 struct btrfs_block_group,
 162						 bg_list);
 163			list_del_init(&cache->bg_list);
 164			btrfs_unfreeze_block_group(cache);
 165			btrfs_put_block_group(cache);
 166		}
 167		WARN_ON(!list_empty(&transaction->dev_update_list));
 168		kfree(transaction);
 169	}
 170}
 171
 172static noinline void switch_commit_roots(struct btrfs_trans_handle *trans)
 173{
 174	struct btrfs_transaction *cur_trans = trans->transaction;
 175	struct btrfs_fs_info *fs_info = trans->fs_info;
 176	struct btrfs_root *root, *tmp;
 177
 178	/*
 179	 * At this point no one can be using this transaction to modify any tree
 180	 * and no one can start another transaction to modify any tree either.
 
 181	 */
 182	ASSERT(cur_trans->state == TRANS_STATE_COMMIT_DOING);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 183
 184	down_write(&fs_info->commit_root_sem);
 
 
 
 185
 186	if (test_bit(BTRFS_FS_RELOC_RUNNING, &fs_info->flags))
 187		fs_info->last_reloc_trans = trans->transid;
 
 
 188
 189	list_for_each_entry_safe(root, tmp, &cur_trans->switch_commits,
 
 190				 dirty_list) {
 191		list_del_init(&root->dirty_list);
 192		free_extent_buffer(root->commit_root);
 193		root->commit_root = btrfs_root_node(root);
 194		extent_io_tree_release(&root->dirty_log_pages);
 195		btrfs_qgroup_clean_swapped_blocks(root);
 
 196	}
 197
 198	/* We can free old roots now. */
 199	spin_lock(&cur_trans->dropped_roots_lock);
 200	while (!list_empty(&cur_trans->dropped_roots)) {
 201		root = list_first_entry(&cur_trans->dropped_roots,
 202					struct btrfs_root, root_list);
 203		list_del_init(&root->root_list);
 204		spin_unlock(&cur_trans->dropped_roots_lock);
 205		btrfs_free_log(trans, root);
 206		btrfs_drop_and_free_fs_root(fs_info, root);
 207		spin_lock(&cur_trans->dropped_roots_lock);
 208	}
 209	spin_unlock(&cur_trans->dropped_roots_lock);
 210
 211	up_write(&fs_info->commit_root_sem);
 212}
 213
 214static inline void extwriter_counter_inc(struct btrfs_transaction *trans,
 215					 unsigned int type)
 216{
 217	if (type & TRANS_EXTWRITERS)
 218		atomic_inc(&trans->num_extwriters);
 219}
 220
 221static inline void extwriter_counter_dec(struct btrfs_transaction *trans,
 222					 unsigned int type)
 223{
 224	if (type & TRANS_EXTWRITERS)
 225		atomic_dec(&trans->num_extwriters);
 226}
 227
 228static inline void extwriter_counter_init(struct btrfs_transaction *trans,
 229					  unsigned int type)
 230{
 231	atomic_set(&trans->num_extwriters, ((type & TRANS_EXTWRITERS) ? 1 : 0));
 232}
 233
 234static inline int extwriter_counter_read(struct btrfs_transaction *trans)
 235{
 236	return atomic_read(&trans->num_extwriters);
 237}
 238
 239/*
 240 * To be called after doing the chunk btree updates right after allocating a new
 241 * chunk (after btrfs_chunk_alloc_add_chunk_item() is called), when removing a
 242 * chunk after all chunk btree updates and after finishing the second phase of
 243 * chunk allocation (btrfs_create_pending_block_groups()) in case some block
 244 * group had its chunk item insertion delayed to the second phase.
 245 */
 246void btrfs_trans_release_chunk_metadata(struct btrfs_trans_handle *trans)
 247{
 248	struct btrfs_fs_info *fs_info = trans->fs_info;
 249
 250	if (!trans->chunk_bytes_reserved)
 251		return;
 252
 253	btrfs_block_rsv_release(fs_info, &fs_info->chunk_block_rsv,
 254				trans->chunk_bytes_reserved, NULL);
 255	trans->chunk_bytes_reserved = 0;
 256}
 257
 258/*
 259 * either allocate a new transaction or hop into the existing one
 260 */
 261static noinline int join_transaction(struct btrfs_fs_info *fs_info,
 262				     unsigned int type)
 263{
 264	struct btrfs_transaction *cur_trans;
 265
 266	spin_lock(&fs_info->trans_lock);
 267loop:
 268	/* The file system has been taken offline. No new transactions. */
 269	if (BTRFS_FS_ERROR(fs_info)) {
 270		spin_unlock(&fs_info->trans_lock);
 271		return -EROFS;
 272	}
 273
 274	cur_trans = fs_info->running_transaction;
 275	if (cur_trans) {
 276		if (TRANS_ABORTED(cur_trans)) {
 277			const int abort_error = cur_trans->aborted;
 278
 279			spin_unlock(&fs_info->trans_lock);
 280			return abort_error;
 281		}
 282		if (btrfs_blocked_trans_types[cur_trans->state] & type) {
 283			spin_unlock(&fs_info->trans_lock);
 284			return -EBUSY;
 285		}
 286		refcount_inc(&cur_trans->use_count);
 287		atomic_inc(&cur_trans->num_writers);
 288		extwriter_counter_inc(cur_trans, type);
 289		spin_unlock(&fs_info->trans_lock);
 290		btrfs_lockdep_acquire(fs_info, btrfs_trans_num_writers);
 291		btrfs_lockdep_acquire(fs_info, btrfs_trans_num_extwriters);
 292		return 0;
 293	}
 294	spin_unlock(&fs_info->trans_lock);
 295
 296	/*
 297	 * If we are ATTACH or TRANS_JOIN_NOSTART, we just want to catch the
 298	 * current transaction, and commit it. If there is no transaction, just
 299	 * return ENOENT.
 300	 */
 301	if (type == TRANS_ATTACH || type == TRANS_JOIN_NOSTART)
 302		return -ENOENT;
 303
 304	/*
 305	 * JOIN_NOLOCK only happens during the transaction commit, so
 306	 * it is impossible that ->running_transaction is NULL
 307	 */
 308	BUG_ON(type == TRANS_JOIN_NOLOCK);
 309
 310	cur_trans = kmalloc(sizeof(*cur_trans), GFP_NOFS);
 311	if (!cur_trans)
 312		return -ENOMEM;
 313
 314	btrfs_lockdep_acquire(fs_info, btrfs_trans_num_writers);
 315	btrfs_lockdep_acquire(fs_info, btrfs_trans_num_extwriters);
 316
 317	spin_lock(&fs_info->trans_lock);
 318	if (fs_info->running_transaction) {
 319		/*
 320		 * someone started a transaction after we unlocked.  Make sure
 321		 * to redo the checks above
 322		 */
 323		btrfs_lockdep_release(fs_info, btrfs_trans_num_extwriters);
 324		btrfs_lockdep_release(fs_info, btrfs_trans_num_writers);
 325		kfree(cur_trans);
 326		goto loop;
 327	} else if (BTRFS_FS_ERROR(fs_info)) {
 328		spin_unlock(&fs_info->trans_lock);
 329		btrfs_lockdep_release(fs_info, btrfs_trans_num_extwriters);
 330		btrfs_lockdep_release(fs_info, btrfs_trans_num_writers);
 331		kfree(cur_trans);
 332		return -EROFS;
 333	}
 334
 335	cur_trans->fs_info = fs_info;
 336	atomic_set(&cur_trans->pending_ordered, 0);
 337	init_waitqueue_head(&cur_trans->pending_wait);
 338	atomic_set(&cur_trans->num_writers, 1);
 339	extwriter_counter_init(cur_trans, type);
 340	init_waitqueue_head(&cur_trans->writer_wait);
 341	init_waitqueue_head(&cur_trans->commit_wait);
 
 342	cur_trans->state = TRANS_STATE_RUNNING;
 343	/*
 344	 * One for this trans handle, one so it will live on until we
 345	 * commit the transaction.
 346	 */
 347	refcount_set(&cur_trans->use_count, 2);
 
 348	cur_trans->flags = 0;
 349	cur_trans->start_time = ktime_get_seconds();
 350
 351	memset(&cur_trans->delayed_refs, 0, sizeof(cur_trans->delayed_refs));
 352
 353	xa_init(&cur_trans->delayed_refs.head_refs);
 354	xa_init(&cur_trans->delayed_refs.dirty_extents);
 
 355
 356	/*
 357	 * although the tree mod log is per file system and not per transaction,
 358	 * the log must never go across transaction boundaries.
 359	 */
 360	smp_mb();
 361	if (!list_empty(&fs_info->tree_mod_seq_list))
 362		WARN(1, KERN_ERR "BTRFS: tree_mod_seq_list not empty when creating a fresh transaction\n");
 363	if (!RB_EMPTY_ROOT(&fs_info->tree_mod_log))
 364		WARN(1, KERN_ERR "BTRFS: tree_mod_log rb tree not empty when creating a fresh transaction\n");
 365	atomic64_set(&fs_info->tree_mod_seq, 0);
 366
 367	spin_lock_init(&cur_trans->delayed_refs.lock);
 368
 369	INIT_LIST_HEAD(&cur_trans->pending_snapshots);
 370	INIT_LIST_HEAD(&cur_trans->dev_update_list);
 371	INIT_LIST_HEAD(&cur_trans->switch_commits);
 372	INIT_LIST_HEAD(&cur_trans->dirty_bgs);
 373	INIT_LIST_HEAD(&cur_trans->io_bgs);
 374	INIT_LIST_HEAD(&cur_trans->dropped_roots);
 375	mutex_init(&cur_trans->cache_write_mutex);
 
 376	spin_lock_init(&cur_trans->dirty_bgs_lock);
 377	INIT_LIST_HEAD(&cur_trans->deleted_bgs);
 378	spin_lock_init(&cur_trans->dropped_roots_lock);
 379	list_add_tail(&cur_trans->list, &fs_info->trans_list);
 380	extent_io_tree_init(fs_info, &cur_trans->dirty_pages,
 381			IO_TREE_TRANS_DIRTY_PAGES);
 382	extent_io_tree_init(fs_info, &cur_trans->pinned_extents,
 383			IO_TREE_FS_PINNED_EXTENTS);
 384	btrfs_set_fs_generation(fs_info, fs_info->generation + 1);
 385	cur_trans->transid = fs_info->generation;
 386	fs_info->running_transaction = cur_trans;
 387	cur_trans->aborted = 0;
 388	spin_unlock(&fs_info->trans_lock);
 389
 390	return 0;
 391}
 392
 393/*
 394 * This does all the record keeping required to make sure that a shareable root
 395 * is properly recorded in a given transaction.  This is required to make sure
 396 * the old root from before we joined the transaction is deleted when the
 397 * transaction commits.
 398 */
 399static int record_root_in_trans(struct btrfs_trans_handle *trans,
 400			       struct btrfs_root *root,
 401			       int force)
 402{
 403	struct btrfs_fs_info *fs_info = root->fs_info;
 404	int ret = 0;
 405
 406	if ((test_bit(BTRFS_ROOT_SHAREABLE, &root->state) &&
 407	    btrfs_get_root_last_trans(root) < trans->transid) || force) {
 408		WARN_ON(!force && root->commit_root != root->node);
 
 409
 410		/*
 411		 * see below for IN_TRANS_SETUP usage rules
 412		 * we have the reloc mutex held now, so there
 413		 * is only one writer in this function
 414		 */
 415		set_bit(BTRFS_ROOT_IN_TRANS_SETUP, &root->state);
 416
 417		/* make sure readers find IN_TRANS_SETUP before
 418		 * they find our root->last_trans update
 419		 */
 420		smp_wmb();
 421
 422		spin_lock(&fs_info->fs_roots_radix_lock);
 423		if (btrfs_get_root_last_trans(root) == trans->transid && !force) {
 424			spin_unlock(&fs_info->fs_roots_radix_lock);
 425			return 0;
 426		}
 427		radix_tree_tag_set(&fs_info->fs_roots_radix,
 428				   (unsigned long)btrfs_root_id(root),
 429				   BTRFS_ROOT_TRANS_TAG);
 430		spin_unlock(&fs_info->fs_roots_radix_lock);
 431		btrfs_set_root_last_trans(root, trans->transid);
 432
 433		/* this is pretty tricky.  We don't want to
 434		 * take the relocation lock in btrfs_record_root_in_trans
 435		 * unless we're really doing the first setup for this root in
 436		 * this transaction.
 437		 *
 438		 * Normally we'd use root->last_trans as a flag to decide
 439		 * if we want to take the expensive mutex.
 440		 *
 441		 * But, we have to set root->last_trans before we
 442		 * init the relocation root, otherwise, we trip over warnings
 443		 * in ctree.c.  The solution used here is to flag ourselves
 444		 * with root IN_TRANS_SETUP.  When this is 1, we're still
 445		 * fixing up the reloc trees and everyone must wait.
 446		 *
 447		 * When this is zero, they can trust root->last_trans and fly
 448		 * through btrfs_record_root_in_trans without having to take the
 449		 * lock.  smp_wmb() makes sure that all the writes above are
 450		 * done before we pop in the zero below
 451		 */
 452		ret = btrfs_init_reloc_root(trans, root);
 453		smp_mb__before_atomic();
 454		clear_bit(BTRFS_ROOT_IN_TRANS_SETUP, &root->state);
 455	}
 456	return ret;
 457}
 458
 459
 460void btrfs_add_dropped_root(struct btrfs_trans_handle *trans,
 461			    struct btrfs_root *root)
 462{
 463	struct btrfs_fs_info *fs_info = root->fs_info;
 464	struct btrfs_transaction *cur_trans = trans->transaction;
 465
 466	/* Add ourselves to the transaction dropped list */
 467	spin_lock(&cur_trans->dropped_roots_lock);
 468	list_add_tail(&root->root_list, &cur_trans->dropped_roots);
 469	spin_unlock(&cur_trans->dropped_roots_lock);
 470
 471	/* Make sure we don't try to update the root at commit time */
 472	spin_lock(&fs_info->fs_roots_radix_lock);
 473	radix_tree_tag_clear(&fs_info->fs_roots_radix,
 474			     (unsigned long)btrfs_root_id(root),
 475			     BTRFS_ROOT_TRANS_TAG);
 476	spin_unlock(&fs_info->fs_roots_radix_lock);
 477}
 478
 479int btrfs_record_root_in_trans(struct btrfs_trans_handle *trans,
 480			       struct btrfs_root *root)
 481{
 482	struct btrfs_fs_info *fs_info = root->fs_info;
 483	int ret;
 484
 485	if (!test_bit(BTRFS_ROOT_SHAREABLE, &root->state))
 486		return 0;
 487
 488	/*
 489	 * see record_root_in_trans for comments about IN_TRANS_SETUP usage
 490	 * and barriers
 491	 */
 492	smp_rmb();
 493	if (btrfs_get_root_last_trans(root) == trans->transid &&
 494	    !test_bit(BTRFS_ROOT_IN_TRANS_SETUP, &root->state))
 495		return 0;
 496
 497	mutex_lock(&fs_info->reloc_mutex);
 498	ret = record_root_in_trans(trans, root, 0);
 499	mutex_unlock(&fs_info->reloc_mutex);
 500
 501	return ret;
 502}
 503
 504static inline int is_transaction_blocked(struct btrfs_transaction *trans)
 505{
 506	return (trans->state >= TRANS_STATE_COMMIT_START &&
 507		trans->state < TRANS_STATE_UNBLOCKED &&
 508		!TRANS_ABORTED(trans));
 509}
 510
 511/* wait for commit against the current transaction to become unblocked
 512 * when this is done, it is safe to start a new transaction, but the current
 513 * transaction might not be fully on disk.
 514 */
 515static void wait_current_trans(struct btrfs_fs_info *fs_info)
 516{
 517	struct btrfs_transaction *cur_trans;
 518
 519	spin_lock(&fs_info->trans_lock);
 520	cur_trans = fs_info->running_transaction;
 521	if (cur_trans && is_transaction_blocked(cur_trans)) {
 522		refcount_inc(&cur_trans->use_count);
 523		spin_unlock(&fs_info->trans_lock);
 524
 525		btrfs_might_wait_for_state(fs_info, BTRFS_LOCKDEP_TRANS_UNBLOCKED);
 526		wait_event(fs_info->transaction_wait,
 527			   cur_trans->state >= TRANS_STATE_UNBLOCKED ||
 528			   TRANS_ABORTED(cur_trans));
 529		btrfs_put_transaction(cur_trans);
 530	} else {
 531		spin_unlock(&fs_info->trans_lock);
 532	}
 533}
 534
 535static int may_wait_transaction(struct btrfs_fs_info *fs_info, int type)
 536{
 537	if (test_bit(BTRFS_FS_LOG_RECOVERING, &fs_info->flags))
 538		return 0;
 539
 540	if (type == TRANS_START)
 
 
 
 
 541		return 1;
 542
 543	return 0;
 544}
 545
 546static inline bool need_reserve_reloc_root(struct btrfs_root *root)
 547{
 548	struct btrfs_fs_info *fs_info = root->fs_info;
 549
 550	if (!fs_info->reloc_ctl ||
 551	    !test_bit(BTRFS_ROOT_SHAREABLE, &root->state) ||
 552	    btrfs_root_id(root) == BTRFS_TREE_RELOC_OBJECTID ||
 553	    root->reloc_root)
 554		return false;
 555
 556	return true;
 557}
 558
 559static int btrfs_reserve_trans_metadata(struct btrfs_fs_info *fs_info,
 560					enum btrfs_reserve_flush_enum flush,
 561					u64 num_bytes,
 562					u64 *delayed_refs_bytes)
 563{
 564	struct btrfs_space_info *si = fs_info->trans_block_rsv.space_info;
 565	u64 bytes = num_bytes + *delayed_refs_bytes;
 566	int ret;
 567
 568	/*
 569	 * We want to reserve all the bytes we may need all at once, so we only
 570	 * do 1 enospc flushing cycle per transaction start.
 571	 */
 572	ret = btrfs_reserve_metadata_bytes(fs_info, si, bytes, flush);
 573
 574	/*
 575	 * If we are an emergency flush, which can steal from the global block
 576	 * reserve, then attempt to not reserve space for the delayed refs, as
 577	 * we will consume space for them from the global block reserve.
 578	 */
 579	if (ret && flush == BTRFS_RESERVE_FLUSH_ALL_STEAL) {
 580		bytes -= *delayed_refs_bytes;
 581		*delayed_refs_bytes = 0;
 582		ret = btrfs_reserve_metadata_bytes(fs_info, si, bytes, flush);
 583	}
 584
 585	return ret;
 586}
 587
 588static struct btrfs_trans_handle *
 589start_transaction(struct btrfs_root *root, unsigned int num_items,
 590		  unsigned int type, enum btrfs_reserve_flush_enum flush,
 591		  bool enforce_qgroups)
 592{
 593	struct btrfs_fs_info *fs_info = root->fs_info;
 594	struct btrfs_block_rsv *delayed_refs_rsv = &fs_info->delayed_refs_rsv;
 595	struct btrfs_block_rsv *trans_rsv = &fs_info->trans_block_rsv;
 596	struct btrfs_trans_handle *h;
 597	struct btrfs_transaction *cur_trans;
 598	u64 num_bytes = 0;
 599	u64 qgroup_reserved = 0;
 600	u64 delayed_refs_bytes = 0;
 601	bool reloc_reserved = false;
 602	bool do_chunk_alloc = false;
 603	int ret;
 604
 605	if (BTRFS_FS_ERROR(fs_info))
 
 
 
 606		return ERR_PTR(-EROFS);
 607
 608	if (current->journal_info) {
 609		WARN_ON(type & TRANS_EXTWRITERS);
 610		h = current->journal_info;
 611		refcount_inc(&h->use_count);
 612		WARN_ON(refcount_read(&h->use_count) > 2);
 613		h->orig_rsv = h->block_rsv;
 614		h->block_rsv = NULL;
 615		goto got_it;
 616	}
 617
 618	/*
 619	 * Do the reservation before we join the transaction so we can do all
 620	 * the appropriate flushing if need be.
 621	 */
 622	if (num_items && root != fs_info->chunk_root) {
 623		qgroup_reserved = num_items * fs_info->nodesize;
 624		/*
 625		 * Use prealloc for now, as there might be a currently running
 626		 * transaction that could free this reserved space prematurely
 627		 * by committing.
 628		 */
 629		ret = btrfs_qgroup_reserve_meta_prealloc(root, qgroup_reserved,
 630							 enforce_qgroups, false);
 631		if (ret)
 632			return ERR_PTR(ret);
 633
 634		num_bytes = btrfs_calc_insert_metadata_size(fs_info, num_items);
 635		/*
 636		 * If we plan to insert/update/delete "num_items" from a btree,
 637		 * we will also generate delayed refs for extent buffers in the
 638		 * respective btree paths, so reserve space for the delayed refs
 639		 * that will be generated by the caller as it modifies btrees.
 640		 * Try to reserve them to avoid excessive use of the global
 641		 * block reserve.
 642		 */
 643		delayed_refs_bytes = btrfs_calc_delayed_ref_bytes(fs_info, num_items);
 644
 645		/*
 646		 * Do the reservation for the relocation root creation
 647		 */
 648		if (need_reserve_reloc_root(root)) {
 649			num_bytes += fs_info->nodesize;
 650			reloc_reserved = true;
 651		}
 652
 653		ret = btrfs_reserve_trans_metadata(fs_info, flush, num_bytes,
 654						   &delayed_refs_bytes);
 655		if (ret)
 656			goto reserve_fail;
 657
 658		btrfs_block_rsv_add_bytes(trans_rsv, num_bytes, true);
 659
 660		if (trans_rsv->space_info->force_alloc)
 661			do_chunk_alloc = true;
 662	} else if (num_items == 0 && flush == BTRFS_RESERVE_FLUSH_ALL &&
 663		   !btrfs_block_rsv_full(delayed_refs_rsv)) {
 664		/*
 665		 * Some people call with btrfs_start_transaction(root, 0)
 666		 * because they can be throttled, but have some other mechanism
 667		 * for reserving space.  We still want these guys to refill the
 668		 * delayed block_rsv so just add 1 items worth of reservation
 669		 * here.
 670		 */
 671		ret = btrfs_delayed_refs_rsv_refill(fs_info, flush);
 672		if (ret)
 673			goto reserve_fail;
 674	}
 675again:
 676	h = kmem_cache_zalloc(btrfs_trans_handle_cachep, GFP_NOFS);
 677	if (!h) {
 678		ret = -ENOMEM;
 679		goto alloc_fail;
 680	}
 681
 682	/*
 683	 * If we are JOIN_NOLOCK we're already committing a transaction and
 684	 * waiting on this guy, so we don't need to do the sb_start_intwrite
 685	 * because we're already holding a ref.  We need this because we could
 686	 * have raced in and did an fsync() on a file which can kick a commit
 687	 * and then we deadlock with somebody doing a freeze.
 688	 *
 689	 * If we are ATTACH, it means we just want to catch the current
 690	 * transaction and commit it, so we needn't do sb_start_intwrite(). 
 691	 */
 692	if (type & __TRANS_FREEZABLE)
 693		sb_start_intwrite(fs_info->sb);
 694
 695	if (may_wait_transaction(fs_info, type))
 696		wait_current_trans(fs_info);
 697
 698	do {
 699		ret = join_transaction(fs_info, type);
 700		if (ret == -EBUSY) {
 701			wait_current_trans(fs_info);
 702			if (unlikely(type == TRANS_ATTACH ||
 703				     type == TRANS_JOIN_NOSTART))
 704				ret = -ENOENT;
 705		}
 706	} while (ret == -EBUSY);
 707
 708	if (ret < 0)
 709		goto join_fail;
 710
 711	cur_trans = fs_info->running_transaction;
 712
 713	h->transid = cur_trans->transid;
 714	h->transaction = cur_trans;
 715	refcount_set(&h->use_count, 1);
 
 716	h->fs_info = root->fs_info;
 717
 718	h->type = type;
 
 
 719	INIT_LIST_HEAD(&h->new_bgs);
 720	btrfs_init_metadata_block_rsv(fs_info, &h->delayed_rsv, BTRFS_BLOCK_RSV_DELOPS);
 721
 722	smp_mb();
 723	if (cur_trans->state >= TRANS_STATE_COMMIT_START &&
 724	    may_wait_transaction(fs_info, type)) {
 725		current->journal_info = h;
 726		btrfs_commit_transaction(h);
 727		goto again;
 728	}
 729
 730	if (num_bytes) {
 731		trace_btrfs_space_reservation(fs_info, "transaction",
 732					      h->transid, num_bytes, 1);
 733		h->block_rsv = trans_rsv;
 734		h->bytes_reserved = num_bytes;
 735		if (delayed_refs_bytes > 0) {
 736			trace_btrfs_space_reservation(fs_info,
 737						      "local_delayed_refs_rsv",
 738						      h->transid,
 739						      delayed_refs_bytes, 1);
 740			h->delayed_refs_bytes_reserved = delayed_refs_bytes;
 741			btrfs_block_rsv_add_bytes(&h->delayed_rsv, delayed_refs_bytes, true);
 742			delayed_refs_bytes = 0;
 743		}
 744		h->reloc_reserved = reloc_reserved;
 745	}
 746
 747got_it:
 748	if (!current->journal_info)
 749		current->journal_info = h;
 750
 751	/*
 752	 * If the space_info is marked ALLOC_FORCE then we'll get upgraded to
 753	 * ALLOC_FORCE the first run through, and then we won't allocate for
 754	 * anybody else who races in later.  We don't care about the return
 755	 * value here.
 756	 */
 757	if (do_chunk_alloc && num_bytes) {
 758		u64 flags = h->block_rsv->space_info->flags;
 759
 760		btrfs_chunk_alloc(h, btrfs_get_alloc_profile(fs_info, flags),
 761				  CHUNK_ALLOC_NO_FORCE);
 762	}
 763
 764	/*
 765	 * btrfs_record_root_in_trans() needs to alloc new extents, and may
 766	 * call btrfs_join_transaction() while we're also starting a
 767	 * transaction.
 768	 *
 769	 * Thus it need to be called after current->journal_info initialized,
 770	 * or we can deadlock.
 771	 */
 772	ret = btrfs_record_root_in_trans(h, root);
 773	if (ret) {
 774		/*
 775		 * The transaction handle is fully initialized and linked with
 776		 * other structures so it needs to be ended in case of errors,
 777		 * not just freed.
 778		 */
 779		btrfs_end_transaction(h);
 780		goto reserve_fail;
 781	}
 782	/*
 783	 * Now that we have found a transaction to be a part of, convert the
 784	 * qgroup reservation from prealloc to pertrans. A different transaction
 785	 * can't race in and free our pertrans out from under us.
 786	 */
 787	if (qgroup_reserved)
 788		btrfs_qgroup_convert_reserved_meta(root, qgroup_reserved);
 789
 
 
 790	return h;
 791
 792join_fail:
 793	if (type & __TRANS_FREEZABLE)
 794		sb_end_intwrite(fs_info->sb);
 795	kmem_cache_free(btrfs_trans_handle_cachep, h);
 796alloc_fail:
 797	if (num_bytes)
 798		btrfs_block_rsv_release(fs_info, trans_rsv, num_bytes, NULL);
 799	if (delayed_refs_bytes)
 800		btrfs_space_info_free_bytes_may_use(fs_info, trans_rsv->space_info,
 801						    delayed_refs_bytes);
 802reserve_fail:
 803	btrfs_qgroup_free_meta_prealloc(root, qgroup_reserved);
 804	return ERR_PTR(ret);
 805}
 806
 807struct btrfs_trans_handle *btrfs_start_transaction(struct btrfs_root *root,
 808						   unsigned int num_items)
 809{
 810	return start_transaction(root, num_items, TRANS_START,
 811				 BTRFS_RESERVE_FLUSH_ALL, true);
 812}
 813
 814struct btrfs_trans_handle *btrfs_start_transaction_fallback_global_rsv(
 815					struct btrfs_root *root,
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 816					unsigned int num_items)
 817{
 818	return start_transaction(root, num_items, TRANS_START,
 819				 BTRFS_RESERVE_FLUSH_ALL_STEAL, false);
 820}
 821
 822struct btrfs_trans_handle *btrfs_join_transaction(struct btrfs_root *root)
 823{
 824	return start_transaction(root, 0, TRANS_JOIN, BTRFS_RESERVE_NO_FLUSH,
 825				 true);
 826}
 827
 828struct btrfs_trans_handle *btrfs_join_transaction_spacecache(struct btrfs_root *root)
 829{
 830	return start_transaction(root, 0, TRANS_JOIN_NOLOCK,
 831				 BTRFS_RESERVE_NO_FLUSH, true);
 832}
 833
 834/*
 835 * Similar to regular join but it never starts a transaction when none is
 836 * running or when there's a running one at a state >= TRANS_STATE_UNBLOCKED.
 837 * This is similar to btrfs_attach_transaction() but it allows the join to
 838 * happen if the transaction commit already started but it's not yet in the
 839 * "doing" phase (the state is < TRANS_STATE_COMMIT_DOING).
 840 */
 841struct btrfs_trans_handle *btrfs_join_transaction_nostart(struct btrfs_root *root)
 842{
 843	return start_transaction(root, 0, TRANS_JOIN_NOSTART,
 844				 BTRFS_RESERVE_NO_FLUSH, true);
 845}
 846
 847/*
 848 * Catch the running transaction.
 849 *
 850 * It is used when we want to commit the current the transaction, but
 851 * don't want to start a new one.
 852 *
 853 * Note: If this function return -ENOENT, it just means there is no
 854 * running transaction. But it is possible that the inactive transaction
 855 * is still in the memory, not fully on disk. If you hope there is no
 856 * inactive transaction in the fs when -ENOENT is returned, you should
 857 * invoke
 858 *     btrfs_attach_transaction_barrier()
 859 */
 860struct btrfs_trans_handle *btrfs_attach_transaction(struct btrfs_root *root)
 861{
 862	return start_transaction(root, 0, TRANS_ATTACH,
 863				 BTRFS_RESERVE_NO_FLUSH, true);
 864}
 865
 866/*
 867 * Catch the running transaction.
 868 *
 869 * It is similar to the above function, the difference is this one
 870 * will wait for all the inactive transactions until they fully
 871 * complete.
 872 */
 873struct btrfs_trans_handle *
 874btrfs_attach_transaction_barrier(struct btrfs_root *root)
 875{
 876	struct btrfs_trans_handle *trans;
 877
 878	trans = start_transaction(root, 0, TRANS_ATTACH,
 879				  BTRFS_RESERVE_NO_FLUSH, true);
 880	if (trans == ERR_PTR(-ENOENT)) {
 881		int ret;
 882
 883		ret = btrfs_wait_for_commit(root->fs_info, 0);
 884		if (ret)
 885			return ERR_PTR(ret);
 886	}
 887
 888	return trans;
 889}
 890
 891/* Wait for a transaction commit to reach at least the given state. */
 892static noinline void wait_for_commit(struct btrfs_transaction *commit,
 893				     const enum btrfs_trans_state min_state)
 894{
 895	struct btrfs_fs_info *fs_info = commit->fs_info;
 896	u64 transid = commit->transid;
 897	bool put = false;
 898
 899	/*
 900	 * At the moment this function is called with min_state either being
 901	 * TRANS_STATE_COMPLETED or TRANS_STATE_SUPER_COMMITTED.
 902	 */
 903	if (min_state == TRANS_STATE_COMPLETED)
 904		btrfs_might_wait_for_state(fs_info, BTRFS_LOCKDEP_TRANS_COMPLETED);
 905	else
 906		btrfs_might_wait_for_state(fs_info, BTRFS_LOCKDEP_TRANS_SUPER_COMMITTED);
 907
 908	while (1) {
 909		wait_event(commit->commit_wait, commit->state >= min_state);
 910		if (put)
 911			btrfs_put_transaction(commit);
 912
 913		if (min_state < TRANS_STATE_COMPLETED)
 914			break;
 915
 916		/*
 917		 * A transaction isn't really completed until all of the
 918		 * previous transactions are completed, but with fsync we can
 919		 * end up with SUPER_COMMITTED transactions before a COMPLETED
 920		 * transaction. Wait for those.
 921		 */
 922
 923		spin_lock(&fs_info->trans_lock);
 924		commit = list_first_entry_or_null(&fs_info->trans_list,
 925						  struct btrfs_transaction,
 926						  list);
 927		if (!commit || commit->transid > transid) {
 928			spin_unlock(&fs_info->trans_lock);
 929			break;
 930		}
 931		refcount_inc(&commit->use_count);
 932		put = true;
 933		spin_unlock(&fs_info->trans_lock);
 934	}
 935}
 936
 937int btrfs_wait_for_commit(struct btrfs_fs_info *fs_info, u64 transid)
 938{
 939	struct btrfs_transaction *cur_trans = NULL, *t;
 940	int ret = 0;
 941
 942	if (transid) {
 943		if (transid <= btrfs_get_last_trans_committed(fs_info))
 944			goto out;
 945
 946		/* find specified transaction */
 947		spin_lock(&fs_info->trans_lock);
 948		list_for_each_entry(t, &fs_info->trans_list, list) {
 949			if (t->transid == transid) {
 950				cur_trans = t;
 951				refcount_inc(&cur_trans->use_count);
 952				ret = 0;
 953				break;
 954			}
 955			if (t->transid > transid) {
 956				ret = 0;
 957				break;
 958			}
 959		}
 960		spin_unlock(&fs_info->trans_lock);
 961
 962		/*
 963		 * The specified transaction doesn't exist, or we
 964		 * raced with btrfs_commit_transaction
 965		 */
 966		if (!cur_trans) {
 967			if (transid > btrfs_get_last_trans_committed(fs_info))
 968				ret = -EINVAL;
 969			goto out;
 970		}
 971	} else {
 972		/* find newest transaction that is committing | committed */
 973		spin_lock(&fs_info->trans_lock);
 974		list_for_each_entry_reverse(t, &fs_info->trans_list,
 975					    list) {
 976			if (t->state >= TRANS_STATE_COMMIT_START) {
 977				if (t->state == TRANS_STATE_COMPLETED)
 978					break;
 979				cur_trans = t;
 980				refcount_inc(&cur_trans->use_count);
 981				break;
 982			}
 983		}
 984		spin_unlock(&fs_info->trans_lock);
 985		if (!cur_trans)
 986			goto out;  /* nothing committing|committed */
 987	}
 988
 989	wait_for_commit(cur_trans, TRANS_STATE_COMPLETED);
 990	ret = cur_trans->aborted;
 991	btrfs_put_transaction(cur_trans);
 992out:
 993	return ret;
 994}
 995
 996void btrfs_throttle(struct btrfs_fs_info *fs_info)
 997{
 998	wait_current_trans(fs_info);
 
 999}
1000
1001bool btrfs_should_end_transaction(struct btrfs_trans_handle *trans)
1002{
1003	struct btrfs_transaction *cur_trans = trans->transaction;
1004
1005	if (cur_trans->state >= TRANS_STATE_COMMIT_START ||
1006	    test_bit(BTRFS_DELAYED_REFS_FLUSHING, &cur_trans->delayed_refs.flags))
1007		return true;
1008
1009	if (btrfs_check_space_for_delayed_refs(trans->fs_info))
1010		return true;
 
1011
1012	return !!btrfs_block_rsv_check(&trans->fs_info->global_block_rsv, 50);
1013}
1014
1015static void btrfs_trans_release_metadata(struct btrfs_trans_handle *trans)
1016
1017{
 
1018	struct btrfs_fs_info *fs_info = trans->fs_info;
 
 
1019
1020	if (!trans->block_rsv) {
1021		ASSERT(!trans->bytes_reserved);
1022		ASSERT(!trans->delayed_refs_bytes_reserved);
1023		return;
1024	}
1025
1026	if (!trans->bytes_reserved) {
1027		ASSERT(!trans->delayed_refs_bytes_reserved);
1028		return;
 
 
 
1029	}
1030
1031	ASSERT(trans->block_rsv == &fs_info->trans_block_rsv);
1032	trace_btrfs_space_reservation(fs_info, "transaction",
1033				      trans->transid, trans->bytes_reserved, 0);
1034	btrfs_block_rsv_release(fs_info, trans->block_rsv,
1035				trans->bytes_reserved, NULL);
1036	trans->bytes_reserved = 0;
1037
1038	if (!trans->delayed_refs_bytes_reserved)
1039		return;
1040
1041	trace_btrfs_space_reservation(fs_info, "local_delayed_refs_rsv",
1042				      trans->transid,
1043				      trans->delayed_refs_bytes_reserved, 0);
1044	btrfs_block_rsv_release(fs_info, &trans->delayed_rsv,
1045				trans->delayed_refs_bytes_reserved, NULL);
1046	trans->delayed_refs_bytes_reserved = 0;
1047}
1048
1049static int __btrfs_end_transaction(struct btrfs_trans_handle *trans,
1050				   int throttle)
1051{
1052	struct btrfs_fs_info *info = trans->fs_info;
1053	struct btrfs_transaction *cur_trans = trans->transaction;
1054	int ret = 0;
 
 
 
 
1055
1056	if (refcount_read(&trans->use_count) > 1) {
1057		refcount_dec(&trans->use_count);
1058		trans->block_rsv = trans->orig_rsv;
1059		return 0;
1060	}
1061
1062	btrfs_trans_release_metadata(trans);
1063	trans->block_rsv = NULL;
1064
1065	btrfs_create_pending_block_groups(trans);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1066
1067	btrfs_trans_release_chunk_metadata(trans);
1068
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1069	if (trans->type & __TRANS_FREEZABLE)
1070		sb_end_intwrite(info->sb);
1071
1072	WARN_ON(cur_trans != info->running_transaction);
1073	WARN_ON(atomic_read(&cur_trans->num_writers) < 1);
1074	atomic_dec(&cur_trans->num_writers);
1075	extwriter_counter_dec(cur_trans, trans->type);
1076
1077	cond_wake_up(&cur_trans->writer_wait);
1078
1079	btrfs_lockdep_release(info, btrfs_trans_num_extwriters);
1080	btrfs_lockdep_release(info, btrfs_trans_num_writers);
1081
 
1082	btrfs_put_transaction(cur_trans);
1083
1084	if (current->journal_info == trans)
1085		current->journal_info = NULL;
1086
1087	if (throttle)
1088		btrfs_run_delayed_iputs(info);
1089
1090	if (TRANS_ABORTED(trans) || BTRFS_FS_ERROR(info)) {
 
1091		wake_up_process(info->transaction_kthread);
1092		if (TRANS_ABORTED(trans))
1093			ret = trans->aborted;
1094		else
1095			ret = -EROFS;
1096	}
 
1097
1098	kmem_cache_free(btrfs_trans_handle_cachep, trans);
1099	return ret;
 
 
 
 
1100}
1101
1102int btrfs_end_transaction(struct btrfs_trans_handle *trans)
1103{
1104	return __btrfs_end_transaction(trans, 0);
1105}
1106
1107int btrfs_end_transaction_throttle(struct btrfs_trans_handle *trans)
1108{
1109	return __btrfs_end_transaction(trans, 1);
1110}
1111
1112/*
1113 * when btree blocks are allocated, they have some corresponding bits set for
1114 * them in one of two extent_io trees.  This is used to make sure all of
1115 * those extents are sent to disk but does not wait on them
1116 */
1117int btrfs_write_marked_extents(struct btrfs_fs_info *fs_info,
1118			       struct extent_io_tree *dirty_pages, int mark)
1119{
1120	int ret = 0;
 
1121	struct address_space *mapping = fs_info->btree_inode->i_mapping;
1122	struct extent_state *cached_state = NULL;
1123	u64 start = 0;
1124	u64 end;
1125
1126	while (find_first_extent_bit(dirty_pages, start, &start, &end,
1127				     mark, &cached_state)) {
1128		bool wait_writeback = false;
1129
1130		ret = convert_extent_bit(dirty_pages, start, end,
1131					 EXTENT_NEED_WAIT,
1132					 mark, &cached_state);
1133		/*
1134		 * convert_extent_bit can return -ENOMEM, which is most of the
1135		 * time a temporary error. So when it happens, ignore the error
1136		 * and wait for writeback of this range to finish - because we
1137		 * failed to set the bit EXTENT_NEED_WAIT for the range, a call
1138		 * to __btrfs_wait_marked_extents() would not know that
1139		 * writeback for this range started and therefore wouldn't
1140		 * wait for it to finish - we don't want to commit a
1141		 * superblock that points to btree nodes/leafs for which
1142		 * writeback hasn't finished yet (and without errors).
1143		 * We cleanup any entries left in the io tree when committing
1144		 * the transaction (through extent_io_tree_release()).
1145		 */
1146		if (ret == -ENOMEM) {
1147			ret = 0;
1148			wait_writeback = true;
1149		}
1150		if (!ret)
1151			ret = filemap_fdatawrite_range(mapping, start, end);
1152		if (!ret && wait_writeback)
1153			ret = filemap_fdatawait_range(mapping, start, end);
 
 
1154		free_extent_state(cached_state);
1155		if (ret)
1156			break;
1157		cached_state = NULL;
1158		cond_resched();
1159		start = end + 1;
1160	}
1161	return ret;
1162}
1163
1164/*
1165 * when btree blocks are allocated, they have some corresponding bits set for
1166 * them in one of two extent_io trees.  This is used to make sure all of
1167 * those extents are on disk for transaction or log commit.  We wait
1168 * on all the pages and clear them from the dirty pages state tree
1169 */
1170static int __btrfs_wait_marked_extents(struct btrfs_fs_info *fs_info,
1171				       struct extent_io_tree *dirty_pages)
1172{
 
 
1173	struct address_space *mapping = fs_info->btree_inode->i_mapping;
1174	struct extent_state *cached_state = NULL;
1175	u64 start = 0;
1176	u64 end;
1177	int ret = 0;
1178
1179	while (find_first_extent_bit(dirty_pages, start, &start, &end,
1180				     EXTENT_NEED_WAIT, &cached_state)) {
1181		/*
1182		 * Ignore -ENOMEM errors returned by clear_extent_bit().
1183		 * When committing the transaction, we'll remove any entries
1184		 * left in the io tree. For a log commit, we don't remove them
1185		 * after committing the log because the tree can be accessed
1186		 * concurrently - we do it only at transaction commit time when
1187		 * it's safe to do it (through extent_io_tree_release()).
1188		 */
1189		ret = clear_extent_bit(dirty_pages, start, end,
1190				       EXTENT_NEED_WAIT, &cached_state);
1191		if (ret == -ENOMEM)
1192			ret = 0;
1193		if (!ret)
1194			ret = filemap_fdatawait_range(mapping, start, end);
 
 
 
1195		free_extent_state(cached_state);
1196		if (ret)
1197			break;
1198		cached_state = NULL;
1199		cond_resched();
1200		start = end + 1;
1201	}
1202	return ret;
 
 
1203}
1204
1205static int btrfs_wait_extents(struct btrfs_fs_info *fs_info,
1206		       struct extent_io_tree *dirty_pages)
1207{
1208	bool errors = false;
1209	int err;
1210
1211	err = __btrfs_wait_marked_extents(fs_info, dirty_pages);
1212	if (test_and_clear_bit(BTRFS_FS_BTREE_ERR, &fs_info->flags))
1213		errors = true;
1214
1215	if (errors && !err)
1216		err = -EIO;
1217	return err;
1218}
1219
1220int btrfs_wait_tree_log_extents(struct btrfs_root *log_root, int mark)
1221{
1222	struct btrfs_fs_info *fs_info = log_root->fs_info;
1223	struct extent_io_tree *dirty_pages = &log_root->dirty_log_pages;
1224	bool errors = false;
1225	int err;
1226
1227	ASSERT(btrfs_root_id(log_root) == BTRFS_TREE_LOG_OBJECTID);
1228
1229	err = __btrfs_wait_marked_extents(fs_info, dirty_pages);
1230	if ((mark & EXTENT_DIRTY) &&
1231	    test_and_clear_bit(BTRFS_FS_LOG1_ERR, &fs_info->flags))
1232		errors = true;
1233
1234	if ((mark & EXTENT_NEW) &&
1235	    test_and_clear_bit(BTRFS_FS_LOG2_ERR, &fs_info->flags))
1236		errors = true;
1237
1238	if (errors && !err)
1239		err = -EIO;
1240	return err;
1241}
1242
1243/*
1244 * When btree blocks are allocated the corresponding extents are marked dirty.
1245 * This function ensures such extents are persisted on disk for transaction or
1246 * log commit.
1247 *
1248 * @trans: transaction whose dirty pages we'd like to write
1249 */
1250static int btrfs_write_and_wait_transaction(struct btrfs_trans_handle *trans)
 
1251{
1252	int ret;
1253	int ret2;
1254	struct extent_io_tree *dirty_pages = &trans->transaction->dirty_pages;
1255	struct btrfs_fs_info *fs_info = trans->fs_info;
1256	struct blk_plug plug;
1257
1258	blk_start_plug(&plug);
1259	ret = btrfs_write_marked_extents(fs_info, dirty_pages, EXTENT_DIRTY);
1260	blk_finish_plug(&plug);
1261	ret2 = btrfs_wait_extents(fs_info, dirty_pages);
1262
1263	extent_io_tree_release(&trans->transaction->dirty_pages);
1264
1265	if (ret)
1266		return ret;
1267	else if (ret2)
1268		return ret2;
1269	else
1270		return 0;
 
 
 
 
 
 
 
 
 
 
 
 
1271}
1272
1273/*
1274 * this is used to update the root pointer in the tree of tree roots.
1275 *
1276 * But, in the case of the extent allocation tree, updating the root
1277 * pointer may allocate blocks which may change the root of the extent
1278 * allocation tree.
1279 *
1280 * So, this loops and repeats and makes sure the cowonly root didn't
1281 * change while the root pointer was being updated in the metadata.
1282 */
1283static int update_cowonly_root(struct btrfs_trans_handle *trans,
1284			       struct btrfs_root *root)
1285{
1286	int ret;
1287	u64 old_root_bytenr;
1288	u64 old_root_used;
1289	struct btrfs_fs_info *fs_info = root->fs_info;
1290	struct btrfs_root *tree_root = fs_info->tree_root;
1291
1292	old_root_used = btrfs_root_used(&root->root_item);
1293
1294	while (1) {
1295		old_root_bytenr = btrfs_root_bytenr(&root->root_item);
1296		if (old_root_bytenr == root->node->start &&
1297		    old_root_used == btrfs_root_used(&root->root_item))
1298			break;
1299
1300		btrfs_set_root_node(&root->root_item, root->node);
1301		ret = btrfs_update_root(trans, tree_root,
1302					&root->root_key,
1303					&root->root_item);
1304		if (ret)
1305			return ret;
1306
1307		old_root_used = btrfs_root_used(&root->root_item);
1308	}
1309
1310	return 0;
1311}
1312
1313/*
1314 * update all the cowonly tree roots on disk
1315 *
1316 * The error handling in this function may not be obvious. Any of the
1317 * failures will cause the file system to go offline. We still need
1318 * to clean up the delayed refs.
1319 */
1320static noinline int commit_cowonly_roots(struct btrfs_trans_handle *trans)
 
1321{
1322	struct btrfs_fs_info *fs_info = trans->fs_info;
1323	struct list_head *dirty_bgs = &trans->transaction->dirty_bgs;
1324	struct list_head *io_bgs = &trans->transaction->io_bgs;
1325	struct list_head *next;
1326	struct extent_buffer *eb;
1327	int ret;
1328
1329	/*
1330	 * At this point no one can be using this transaction to modify any tree
1331	 * and no one can start another transaction to modify any tree either.
1332	 */
1333	ASSERT(trans->transaction->state == TRANS_STATE_COMMIT_DOING);
1334
1335	eb = btrfs_lock_root_node(fs_info->tree_root);
1336	ret = btrfs_cow_block(trans, fs_info->tree_root, eb, NULL,
1337			      0, &eb, BTRFS_NESTING_COW);
1338	btrfs_tree_unlock(eb);
1339	free_extent_buffer(eb);
1340
1341	if (ret)
1342		return ret;
1343
1344	ret = btrfs_run_dev_stats(trans);
 
 
 
 
1345	if (ret)
1346		return ret;
1347	ret = btrfs_run_dev_replace(trans);
1348	if (ret)
1349		return ret;
1350	ret = btrfs_run_qgroups(trans);
1351	if (ret)
1352		return ret;
1353
1354	ret = btrfs_setup_space_cache(trans);
1355	if (ret)
1356		return ret;
1357
 
 
 
 
1358again:
1359	while (!list_empty(&fs_info->dirty_cowonly_roots)) {
1360		struct btrfs_root *root;
1361		next = fs_info->dirty_cowonly_roots.next;
1362		list_del_init(next);
1363		root = list_entry(next, struct btrfs_root, dirty_list);
1364		clear_bit(BTRFS_ROOT_DIRTY, &root->state);
1365
1366		list_add_tail(&root->dirty_list,
1367			      &trans->transaction->switch_commits);
 
1368		ret = update_cowonly_root(trans, root);
1369		if (ret)
1370			return ret;
 
 
 
1371	}
1372
1373	/* Now flush any delayed refs generated by updating all of the roots */
1374	ret = btrfs_run_delayed_refs(trans, U64_MAX);
1375	if (ret)
1376		return ret;
1377
1378	while (!list_empty(dirty_bgs) || !list_empty(io_bgs)) {
1379		ret = btrfs_write_dirty_block_groups(trans);
1380		if (ret)
1381			return ret;
1382
1383		/*
1384		 * We're writing the dirty block groups, which could generate
1385		 * delayed refs, which could generate more dirty block groups,
1386		 * so we want to keep this flushing in this loop to make sure
1387		 * everything gets run.
1388		 */
1389		ret = btrfs_run_delayed_refs(trans, U64_MAX);
1390		if (ret)
1391			return ret;
1392	}
1393
1394	if (!list_empty(&fs_info->dirty_cowonly_roots))
1395		goto again;
1396
1397	/* Update dev-replace pointer once everything is committed */
1398	fs_info->dev_replace.committed_cursor_left =
1399		fs_info->dev_replace.cursor_left_last_write_of_item;
1400
1401	return 0;
1402}
1403
1404/*
1405 * If we had a pending drop we need to see if there are any others left in our
1406 * dead roots list, and if not clear our bit and wake any waiters.
1407 */
1408void btrfs_maybe_wake_unfinished_drop(struct btrfs_fs_info *fs_info)
1409{
1410	/*
1411	 * We put the drop in progress roots at the front of the list, so if the
1412	 * first entry doesn't have UNFINISHED_DROP set we can wake everybody
1413	 * up.
1414	 */
1415	spin_lock(&fs_info->trans_lock);
1416	if (!list_empty(&fs_info->dead_roots)) {
1417		struct btrfs_root *root = list_first_entry(&fs_info->dead_roots,
1418							   struct btrfs_root,
1419							   root_list);
1420		if (test_bit(BTRFS_ROOT_UNFINISHED_DROP, &root->state)) {
1421			spin_unlock(&fs_info->trans_lock);
1422			return;
1423		}
1424	}
1425	spin_unlock(&fs_info->trans_lock);
1426
1427	btrfs_wake_unfinished_drop(fs_info);
1428}
1429
1430/*
1431 * dead roots are old snapshots that need to be deleted.  This allocates
1432 * a dirty root struct and adds it into the list of dead roots that need to
1433 * be deleted
1434 */
1435void btrfs_add_dead_root(struct btrfs_root *root)
1436{
1437	struct btrfs_fs_info *fs_info = root->fs_info;
1438
1439	spin_lock(&fs_info->trans_lock);
1440	if (list_empty(&root->root_list)) {
1441		btrfs_grab_root(root);
1442
1443		/* We want to process the partially complete drops first. */
1444		if (test_bit(BTRFS_ROOT_UNFINISHED_DROP, &root->state))
1445			list_add(&root->root_list, &fs_info->dead_roots);
1446		else
1447			list_add_tail(&root->root_list, &fs_info->dead_roots);
1448	}
1449	spin_unlock(&fs_info->trans_lock);
1450}
1451
1452/*
1453 * Update each subvolume root and its relocation root, if it exists, in the tree
1454 * of tree roots. Also free log roots if they exist.
1455 */
1456static noinline int commit_fs_roots(struct btrfs_trans_handle *trans)
 
1457{
1458	struct btrfs_fs_info *fs_info = trans->fs_info;
1459	struct btrfs_root *gang[8];
1460	int i;
1461	int ret;
1462
1463	/*
1464	 * At this point no one can be using this transaction to modify any tree
1465	 * and no one can start another transaction to modify any tree either.
1466	 */
1467	ASSERT(trans->transaction->state == TRANS_STATE_COMMIT_DOING);
1468
1469	spin_lock(&fs_info->fs_roots_radix_lock);
1470	while (1) {
1471		ret = radix_tree_gang_lookup_tag(&fs_info->fs_roots_radix,
1472						 (void **)gang, 0,
1473						 ARRAY_SIZE(gang),
1474						 BTRFS_ROOT_TRANS_TAG);
1475		if (ret == 0)
1476			break;
1477		for (i = 0; i < ret; i++) {
1478			struct btrfs_root *root = gang[i];
1479			int ret2;
1480
1481			/*
1482			 * At this point we can neither have tasks logging inodes
1483			 * from a root nor trying to commit a log tree.
1484			 */
1485			ASSERT(atomic_read(&root->log_writers) == 0);
1486			ASSERT(atomic_read(&root->log_commit[0]) == 0);
1487			ASSERT(atomic_read(&root->log_commit[1]) == 0);
1488
1489			radix_tree_tag_clear(&fs_info->fs_roots_radix,
1490					(unsigned long)btrfs_root_id(root),
1491					BTRFS_ROOT_TRANS_TAG);
1492			btrfs_qgroup_free_meta_all_pertrans(root);
1493			spin_unlock(&fs_info->fs_roots_radix_lock);
1494
1495			btrfs_free_log(trans, root);
1496			ret2 = btrfs_update_reloc_root(trans, root);
1497			if (ret2)
1498				return ret2;
 
1499
1500			/* see comments in should_cow_block() */
1501			clear_bit(BTRFS_ROOT_FORCE_COW, &root->state);
1502			smp_mb__after_atomic();
1503
1504			if (root->commit_root != root->node) {
1505				list_add_tail(&root->dirty_list,
1506					&trans->transaction->switch_commits);
1507				btrfs_set_root_node(&root->root_item,
1508						    root->node);
1509			}
1510
1511			ret2 = btrfs_update_root(trans, fs_info->tree_root,
1512						&root->root_key,
1513						&root->root_item);
1514			if (ret2)
1515				return ret2;
1516			spin_lock(&fs_info->fs_roots_radix_lock);
 
 
 
1517		}
1518	}
1519	spin_unlock(&fs_info->fs_roots_radix_lock);
1520	return 0;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1521}
1522
1523/*
1524 * Do all special snapshot related qgroup dirty hack.
1525 *
1526 * Will do all needed qgroup inherit and dirty hack like switch commit
1527 * roots inside one transaction and write all btree into disk, to make
1528 * qgroup works.
1529 */
1530static int qgroup_account_snapshot(struct btrfs_trans_handle *trans,
1531				   struct btrfs_root *src,
1532				   struct btrfs_root *parent,
1533				   struct btrfs_qgroup_inherit *inherit,
1534				   u64 dst_objectid)
1535{
1536	struct btrfs_fs_info *fs_info = src->fs_info;
1537	int ret;
1538
1539	/*
1540	 * Save some performance in the case that qgroups are not enabled. If
1541	 * this check races with the ioctl, rescan will kick in anyway.
1542	 */
1543	if (!btrfs_qgroup_full_accounting(fs_info))
 
 
 
1544		return 0;
 
 
1545
1546	/*
1547	 * Ensure dirty @src will be committed.  Or, after coming
1548	 * commit_fs_roots() and switch_commit_roots(), any dirty but not
1549	 * recorded root will never be updated again, causing an outdated root
1550	 * item.
1551	 */
1552	ret = record_root_in_trans(trans, src, 1);
1553	if (ret)
1554		return ret;
1555
1556	/*
1557	 * btrfs_qgroup_inherit relies on a consistent view of the usage for the
1558	 * src root, so we must run the delayed refs here.
1559	 *
1560	 * However this isn't particularly fool proof, because there's no
1561	 * synchronization keeping us from changing the tree after this point
1562	 * before we do the qgroup_inherit, or even from making changes while
1563	 * we're doing the qgroup_inherit.  But that's a problem for the future,
1564	 * for now flush the delayed refs to narrow the race window where the
1565	 * qgroup counters could end up wrong.
1566	 */
1567	ret = btrfs_run_delayed_refs(trans, U64_MAX);
1568	if (ret) {
1569		btrfs_abort_transaction(trans, ret);
1570		return ret;
1571	}
1572
1573	ret = commit_fs_roots(trans);
1574	if (ret)
1575		goto out;
1576	ret = btrfs_qgroup_account_extents(trans);
 
 
 
1577	if (ret < 0)
1578		goto out;
1579
1580	/* Now qgroup are all updated, we can inherit it to new qgroups */
1581	ret = btrfs_qgroup_inherit(trans, btrfs_root_id(src), dst_objectid,
1582				   btrfs_root_id(parent), inherit);
 
1583	if (ret < 0)
1584		goto out;
1585
1586	/*
1587	 * Now we do a simplified commit transaction, which will:
1588	 * 1) commit all subvolume and extent tree
1589	 *    To ensure all subvolume and extent tree have a valid
1590	 *    commit_root to accounting later insert_dir_item()
1591	 * 2) write all btree blocks onto disk
1592	 *    This is to make sure later btree modification will be cowed
1593	 *    Or commit_root can be populated and cause wrong qgroup numbers
1594	 * In this simplified commit, we don't really care about other trees
1595	 * like chunk and root tree, as they won't affect qgroup.
1596	 * And we don't write super to avoid half committed status.
1597	 */
1598	ret = commit_cowonly_roots(trans);
1599	if (ret)
1600		goto out;
1601	switch_commit_roots(trans);
1602	ret = btrfs_write_and_wait_transaction(trans);
1603	if (ret)
1604		btrfs_handle_fs_error(fs_info, ret,
1605			"Error while writing out transaction for qgroup");
1606
1607out:
 
 
1608	/*
1609	 * Force parent root to be updated, as we recorded it before so its
1610	 * last_trans == cur_transid.
1611	 * Or it won't be committed again onto disk after later
1612	 * insert_dir_item()
1613	 */
1614	if (!ret)
1615		ret = record_root_in_trans(trans, parent, 1);
1616	return ret;
1617}
1618
1619/*
1620 * new snapshots need to be created at a very specific time in the
1621 * transaction commit.  This does the actual creation.
1622 *
1623 * Note:
1624 * If the error which may affect the commitment of the current transaction
1625 * happens, we should return the error number. If the error which just affect
1626 * the creation of the pending snapshots, just return 0.
1627 */
1628static noinline int create_pending_snapshot(struct btrfs_trans_handle *trans,
 
1629				   struct btrfs_pending_snapshot *pending)
1630{
1631
1632	struct btrfs_fs_info *fs_info = trans->fs_info;
1633	struct btrfs_key key;
1634	struct btrfs_root_item *new_root_item;
1635	struct btrfs_root *tree_root = fs_info->tree_root;
1636	struct btrfs_root *root = pending->root;
1637	struct btrfs_root *parent_root;
1638	struct btrfs_block_rsv *rsv;
1639	struct inode *parent_inode = &pending->dir->vfs_inode;
1640	struct btrfs_path *path;
1641	struct btrfs_dir_item *dir_item;
 
1642	struct extent_buffer *tmp;
1643	struct extent_buffer *old;
1644	struct timespec64 cur_time;
1645	int ret = 0;
1646	u64 to_reserve = 0;
1647	u64 index = 0;
1648	u64 objectid;
1649	u64 root_flags;
1650	unsigned int nofs_flags;
1651	struct fscrypt_name fname;
1652
1653	ASSERT(pending->path);
1654	path = pending->path;
1655
1656	ASSERT(pending->root_item);
1657	new_root_item = pending->root_item;
1658
1659	/*
1660	 * We're inside a transaction and must make sure that any potential
1661	 * allocations with GFP_KERNEL in fscrypt won't recurse back to
1662	 * filesystem.
1663	 */
1664	nofs_flags = memalloc_nofs_save();
1665	pending->error = fscrypt_setup_filename(parent_inode,
1666						&pending->dentry->d_name, 0,
1667						&fname);
1668	memalloc_nofs_restore(nofs_flags);
1669	if (pending->error)
1670		goto free_pending;
1671
1672	pending->error = btrfs_get_free_objectid(tree_root, &objectid);
1673	if (pending->error)
1674		goto free_fname;
1675
1676	/*
1677	 * Make qgroup to skip current new snapshot's qgroupid, as it is
1678	 * accounted by later btrfs_qgroup_inherit().
1679	 */
1680	btrfs_set_skip_qgroup(trans, objectid);
1681
1682	btrfs_reloc_pre_snapshot(pending, &to_reserve);
1683
1684	if (to_reserve > 0) {
1685		pending->error = btrfs_block_rsv_add(fs_info,
1686						     &pending->block_rsv,
1687						     to_reserve,
1688						     BTRFS_RESERVE_NO_FLUSH);
1689		if (pending->error)
1690			goto clear_skip_qgroup;
1691	}
1692
1693	key.objectid = objectid;
1694	key.offset = (u64)-1;
1695	key.type = BTRFS_ROOT_ITEM_KEY;
1696
1697	rsv = trans->block_rsv;
1698	trans->block_rsv = &pending->block_rsv;
1699	trans->bytes_reserved = trans->block_rsv->reserved;
1700	trace_btrfs_space_reservation(fs_info, "transaction",
1701				      trans->transid,
1702				      trans->bytes_reserved, 1);
 
 
1703	parent_root = BTRFS_I(parent_inode)->root;
1704	ret = record_root_in_trans(trans, parent_root, 0);
1705	if (ret)
1706		goto fail;
1707	cur_time = current_time(parent_inode);
1708
1709	/*
1710	 * insert the directory item
1711	 */
1712	ret = btrfs_set_inode_index(BTRFS_I(parent_inode), &index);
1713	if (ret) {
1714		btrfs_abort_transaction(trans, ret);
1715		goto fail;
1716	}
1717
1718	/* check if there is a file/dir which has the same name. */
1719	dir_item = btrfs_lookup_dir_item(NULL, parent_root, path,
1720					 btrfs_ino(BTRFS_I(parent_inode)),
1721					 &fname.disk_name, 0);
 
1722	if (dir_item != NULL && !IS_ERR(dir_item)) {
1723		pending->error = -EEXIST;
1724		goto dir_item_existed;
1725	} else if (IS_ERR(dir_item)) {
1726		ret = PTR_ERR(dir_item);
1727		btrfs_abort_transaction(trans, ret);
1728		goto fail;
1729	}
1730	btrfs_release_path(path);
1731
1732	ret = btrfs_create_qgroup(trans, objectid);
1733	if (ret && ret != -EEXIST) {
1734		btrfs_abort_transaction(trans, ret);
1735		goto fail;
1736	}
1737
1738	/*
1739	 * pull in the delayed directory update
1740	 * and the delayed inode item
1741	 * otherwise we corrupt the FS during
1742	 * snapshot
1743	 */
1744	ret = btrfs_run_delayed_items(trans);
1745	if (ret) {	/* Transaction aborted */
1746		btrfs_abort_transaction(trans, ret);
1747		goto fail;
1748	}
1749
1750	ret = record_root_in_trans(trans, root, 0);
1751	if (ret) {
1752		btrfs_abort_transaction(trans, ret);
1753		goto fail;
1754	}
1755	btrfs_set_root_last_snapshot(&root->root_item, trans->transid);
1756	memcpy(new_root_item, &root->root_item, sizeof(*new_root_item));
1757	btrfs_check_and_init_root_item(new_root_item);
1758
1759	root_flags = btrfs_root_flags(new_root_item);
1760	if (pending->readonly)
1761		root_flags |= BTRFS_ROOT_SUBVOL_RDONLY;
1762	else
1763		root_flags &= ~BTRFS_ROOT_SUBVOL_RDONLY;
1764	btrfs_set_root_flags(new_root_item, root_flags);
1765
1766	btrfs_set_root_generation_v2(new_root_item,
1767			trans->transid);
1768	generate_random_guid(new_root_item->uuid);
 
1769	memcpy(new_root_item->parent_uuid, root->root_item.uuid,
1770			BTRFS_UUID_SIZE);
1771	if (!(root_flags & BTRFS_ROOT_SUBVOL_RDONLY)) {
1772		memset(new_root_item->received_uuid, 0,
1773		       sizeof(new_root_item->received_uuid));
1774		memset(&new_root_item->stime, 0, sizeof(new_root_item->stime));
1775		memset(&new_root_item->rtime, 0, sizeof(new_root_item->rtime));
1776		btrfs_set_root_stransid(new_root_item, 0);
1777		btrfs_set_root_rtransid(new_root_item, 0);
1778	}
1779	btrfs_set_stack_timespec_sec(&new_root_item->otime, cur_time.tv_sec);
1780	btrfs_set_stack_timespec_nsec(&new_root_item->otime, cur_time.tv_nsec);
1781	btrfs_set_root_otransid(new_root_item, trans->transid);
1782
1783	old = btrfs_lock_root_node(root);
1784	ret = btrfs_cow_block(trans, root, old, NULL, 0, &old,
1785			      BTRFS_NESTING_COW);
1786	if (ret) {
1787		btrfs_tree_unlock(old);
1788		free_extent_buffer(old);
1789		btrfs_abort_transaction(trans, ret);
1790		goto fail;
1791	}
1792
 
 
1793	ret = btrfs_copy_root(trans, root, old, &tmp, objectid);
1794	/* clean up in any case */
1795	btrfs_tree_unlock(old);
1796	free_extent_buffer(old);
1797	if (ret) {
1798		btrfs_abort_transaction(trans, ret);
1799		goto fail;
1800	}
1801	/* see comments in should_cow_block() */
1802	set_bit(BTRFS_ROOT_FORCE_COW, &root->state);
1803	smp_wmb();
1804
1805	btrfs_set_root_node(new_root_item, tmp);
1806	/* record when the snapshot was created in key.offset */
1807	key.offset = trans->transid;
1808	ret = btrfs_insert_root(trans, tree_root, &key, new_root_item);
1809	btrfs_tree_unlock(tmp);
1810	free_extent_buffer(tmp);
1811	if (ret) {
1812		btrfs_abort_transaction(trans, ret);
1813		goto fail;
1814	}
1815
1816	/*
1817	 * insert root back/forward references
1818	 */
1819	ret = btrfs_add_root_ref(trans, objectid,
1820				 btrfs_root_id(parent_root),
1821				 btrfs_ino(BTRFS_I(parent_inode)), index,
1822				 &fname.disk_name);
1823	if (ret) {
1824		btrfs_abort_transaction(trans, ret);
1825		goto fail;
1826	}
1827
1828	key.offset = (u64)-1;
1829	pending->snap = btrfs_get_new_fs_root(fs_info, objectid, &pending->anon_dev);
1830	if (IS_ERR(pending->snap)) {
1831		ret = PTR_ERR(pending->snap);
1832		pending->snap = NULL;
1833		btrfs_abort_transaction(trans, ret);
1834		goto fail;
1835	}
1836
1837	ret = btrfs_reloc_post_snapshot(trans, pending);
1838	if (ret) {
1839		btrfs_abort_transaction(trans, ret);
1840		goto fail;
1841	}
1842
 
 
 
 
 
 
1843	/*
1844	 * Do special qgroup accounting for snapshot, as we do some qgroup
1845	 * snapshot hack to do fast snapshot.
1846	 * To co-operate with that hack, we do hack again.
1847	 * Or snapshot will be greatly slowed down by a subtree qgroup rescan
1848	 */
1849	if (btrfs_qgroup_mode(fs_info) == BTRFS_QGROUP_MODE_FULL)
1850		ret = qgroup_account_snapshot(trans, root, parent_root,
1851					      pending->inherit, objectid);
1852	else if (btrfs_qgroup_mode(fs_info) == BTRFS_QGROUP_MODE_SIMPLE)
1853		ret = btrfs_qgroup_inherit(trans, btrfs_root_id(root), objectid,
1854					   btrfs_root_id(parent_root), pending->inherit);
1855	if (ret < 0)
1856		goto fail;
1857
1858	ret = btrfs_insert_dir_item(trans, &fname.disk_name,
1859				    BTRFS_I(parent_inode), &key, BTRFS_FT_DIR,
1860				    index);
 
 
 
1861	if (ret) {
1862		btrfs_abort_transaction(trans, ret);
1863		goto fail;
1864	}
1865
1866	btrfs_i_size_write(BTRFS_I(parent_inode), parent_inode->i_size +
1867						  fname.disk_name.len * 2);
1868	inode_set_mtime_to_ts(parent_inode,
1869			      inode_set_ctime_current(parent_inode));
1870	ret = btrfs_update_inode_fallback(trans, BTRFS_I(parent_inode));
1871	if (ret) {
1872		btrfs_abort_transaction(trans, ret);
1873		goto fail;
1874	}
1875	ret = btrfs_uuid_tree_add(trans, new_root_item->uuid,
1876				  BTRFS_UUID_KEY_SUBVOL,
1877				  objectid);
1878	if (ret) {
1879		btrfs_abort_transaction(trans, ret);
1880		goto fail;
1881	}
1882	if (!btrfs_is_empty_uuid(new_root_item->received_uuid)) {
1883		ret = btrfs_uuid_tree_add(trans, new_root_item->received_uuid,
 
1884					  BTRFS_UUID_KEY_RECEIVED_SUBVOL,
1885					  objectid);
1886		if (ret && ret != -EEXIST) {
1887			btrfs_abort_transaction(trans, ret);
1888			goto fail;
1889		}
1890	}
1891
 
 
 
 
 
 
1892fail:
1893	pending->error = ret;
1894dir_item_existed:
1895	trans->block_rsv = rsv;
1896	trans->bytes_reserved = 0;
1897clear_skip_qgroup:
1898	btrfs_clear_skip_qgroup(trans);
1899free_fname:
1900	fscrypt_free_filename(&fname);
1901free_pending:
1902	kfree(new_root_item);
1903	pending->root_item = NULL;
1904	btrfs_free_path(path);
1905	pending->path = NULL;
1906
1907	return ret;
1908}
1909
1910/*
1911 * create all the snapshots we've scheduled for creation
1912 */
1913static noinline int create_pending_snapshots(struct btrfs_trans_handle *trans)
 
1914{
1915	struct btrfs_pending_snapshot *pending, *next;
1916	struct list_head *head = &trans->transaction->pending_snapshots;
1917	int ret = 0;
1918
1919	list_for_each_entry_safe(pending, next, head, list) {
1920		list_del(&pending->list);
1921		ret = create_pending_snapshot(trans, pending);
1922		if (ret)
1923			break;
1924	}
1925	return ret;
1926}
1927
1928static void update_super_roots(struct btrfs_fs_info *fs_info)
1929{
1930	struct btrfs_root_item *root_item;
1931	struct btrfs_super_block *super;
1932
1933	super = fs_info->super_copy;
1934
1935	root_item = &fs_info->chunk_root->root_item;
1936	super->chunk_root = root_item->bytenr;
1937	super->chunk_root_generation = root_item->generation;
1938	super->chunk_root_level = root_item->level;
1939
1940	root_item = &fs_info->tree_root->root_item;
1941	super->root = root_item->bytenr;
1942	super->generation = root_item->generation;
1943	super->root_level = root_item->level;
1944	if (btrfs_test_opt(fs_info, SPACE_CACHE))
1945		super->cache_generation = root_item->generation;
1946	else if (test_bit(BTRFS_FS_CLEANUP_SPACE_CACHE_V1, &fs_info->flags))
1947		super->cache_generation = 0;
1948	if (test_bit(BTRFS_FS_UPDATE_UUID_TREE_GEN, &fs_info->flags))
1949		super->uuid_tree_generation = root_item->generation;
1950}
1951
 
 
 
 
 
 
 
 
 
 
 
 
 
1952int btrfs_transaction_blocked(struct btrfs_fs_info *info)
1953{
1954	struct btrfs_transaction *trans;
1955	int ret = 0;
1956
1957	spin_lock(&info->trans_lock);
1958	trans = info->running_transaction;
1959	if (trans)
1960		ret = is_transaction_blocked(trans);
1961	spin_unlock(&info->trans_lock);
1962	return ret;
1963}
1964
1965void btrfs_commit_transaction_async(struct btrfs_trans_handle *trans)
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1966{
1967	struct btrfs_fs_info *fs_info = trans->fs_info;
 
1968	struct btrfs_transaction *cur_trans;
1969
1970	/* Kick the transaction kthread. */
1971	set_bit(BTRFS_FS_COMMIT_TRANS, &fs_info->flags);
1972	wake_up_process(fs_info->transaction_kthread);
 
 
 
 
 
 
 
 
1973
1974	/* take transaction reference */
1975	cur_trans = trans->transaction;
1976	refcount_inc(&cur_trans->use_count);
1977
1978	btrfs_end_transaction(trans);
1979
1980	/*
1981	 * Wait for the current transaction commit to start and block
1982	 * subsequent transaction joins
1983	 */
1984	btrfs_might_wait_for_state(fs_info, BTRFS_LOCKDEP_TRANS_COMMIT_PREP);
1985	wait_event(fs_info->transaction_blocked_wait,
1986		   cur_trans->state >= TRANS_STATE_COMMIT_START ||
1987		   TRANS_ABORTED(cur_trans));
1988	btrfs_put_transaction(cur_trans);
1989}
1990
1991/*
1992 * If there is a running transaction commit it or if it's already committing,
1993 * wait for its commit to complete. Does not start and commit a new transaction
1994 * if there isn't any running.
1995 */
1996int btrfs_commit_current_transaction(struct btrfs_root *root)
1997{
1998	struct btrfs_trans_handle *trans;
1999
2000	trans = btrfs_attach_transaction_barrier(root);
2001	if (IS_ERR(trans)) {
2002		int ret = PTR_ERR(trans);
 
 
2003
2004		return (ret == -ENOENT) ? 0 : ret;
2005	}
2006
2007	return btrfs_commit_transaction(trans);
 
2008}
2009
2010static void cleanup_transaction(struct btrfs_trans_handle *trans, int err)
 
 
2011{
2012	struct btrfs_fs_info *fs_info = trans->fs_info;
2013	struct btrfs_transaction *cur_trans = trans->transaction;
 
2014
2015	WARN_ON(refcount_read(&trans->use_count) > 1);
2016
2017	btrfs_abort_transaction(trans, err);
2018
2019	spin_lock(&fs_info->trans_lock);
2020
2021	/*
2022	 * If the transaction is removed from the list, it means this
2023	 * transaction has been committed successfully, so it is impossible
2024	 * to call the cleanup function.
2025	 */
2026	BUG_ON(list_empty(&cur_trans->list));
2027
 
2028	if (cur_trans == fs_info->running_transaction) {
2029		cur_trans->state = TRANS_STATE_COMMIT_DOING;
2030		spin_unlock(&fs_info->trans_lock);
2031
2032		/*
2033		 * The thread has already released the lockdep map as reader
2034		 * already in btrfs_commit_transaction().
2035		 */
2036		btrfs_might_wait_for_event(fs_info, btrfs_trans_num_writers);
2037		wait_event(cur_trans->writer_wait,
2038			   atomic_read(&cur_trans->num_writers) == 1);
2039
2040		spin_lock(&fs_info->trans_lock);
2041	}
2042
2043	/*
2044	 * Now that we know no one else is still using the transaction we can
2045	 * remove the transaction from the list of transactions. This avoids
2046	 * the transaction kthread from cleaning up the transaction while some
2047	 * other task is still using it, which could result in a use-after-free
2048	 * on things like log trees, as it forces the transaction kthread to
2049	 * wait for this transaction to be cleaned up by us.
2050	 */
2051	list_del_init(&cur_trans->list);
2052
2053	spin_unlock(&fs_info->trans_lock);
2054
2055	btrfs_cleanup_one_transaction(trans->transaction);
2056
2057	spin_lock(&fs_info->trans_lock);
2058	if (cur_trans == fs_info->running_transaction)
2059		fs_info->running_transaction = NULL;
2060	spin_unlock(&fs_info->trans_lock);
2061
2062	if (trans->type & __TRANS_FREEZABLE)
2063		sb_end_intwrite(fs_info->sb);
2064	btrfs_put_transaction(cur_trans);
2065	btrfs_put_transaction(cur_trans);
2066
2067	trace_btrfs_transaction_commit(fs_info);
2068
2069	if (current->journal_info == trans)
2070		current->journal_info = NULL;
2071
2072	/*
2073	 * If relocation is running, we can't cancel scrub because that will
2074	 * result in a deadlock. Before relocating a block group, relocation
2075	 * pauses scrub, then starts and commits a transaction before unpausing
2076	 * scrub. If the transaction commit is being done by the relocation
2077	 * task or triggered by another task and the relocation task is waiting
2078	 * for the commit, and we end up here due to an error in the commit
2079	 * path, then calling btrfs_scrub_cancel() will deadlock, as we are
2080	 * asking for scrub to stop while having it asked to be paused higher
2081	 * above in relocation code.
2082	 */
2083	if (!test_bit(BTRFS_FS_RELOC_RUNNING, &fs_info->flags))
2084		btrfs_scrub_cancel(fs_info);
2085
2086	kmem_cache_free(btrfs_trans_handle_cachep, trans);
2087}
2088
2089/*
2090 * Release reserved delayed ref space of all pending block groups of the
2091 * transaction and remove them from the list
2092 */
2093static void btrfs_cleanup_pending_block_groups(struct btrfs_trans_handle *trans)
2094{
2095       struct btrfs_fs_info *fs_info = trans->fs_info;
2096       struct btrfs_block_group *block_group, *tmp;
2097
2098       list_for_each_entry_safe(block_group, tmp, &trans->new_bgs, bg_list) {
2099               btrfs_dec_delayed_refs_rsv_bg_inserts(fs_info);
2100               list_del_init(&block_group->bg_list);
2101       }
2102}
2103
2104static inline int btrfs_start_delalloc_flush(struct btrfs_fs_info *fs_info)
2105{
2106	/*
2107	 * We use try_to_writeback_inodes_sb() here because if we used
2108	 * btrfs_start_delalloc_roots we would deadlock with fs freeze.
2109	 * Currently are holding the fs freeze lock, if we do an async flush
2110	 * we'll do btrfs_join_transaction() and deadlock because we need to
2111	 * wait for the fs freeze lock.  Using the direct flushing we benefit
2112	 * from already being in a transaction and our join_transaction doesn't
2113	 * have to re-take the fs freeze lock.
2114	 *
2115	 * Note that try_to_writeback_inodes_sb() will only trigger writeback
2116	 * if it can read lock sb->s_umount. It will always be able to lock it,
2117	 * except when the filesystem is being unmounted or being frozen, but in
2118	 * those cases sync_filesystem() is called, which results in calling
2119	 * writeback_inodes_sb() while holding a write lock on sb->s_umount.
2120	 * Note that we don't call writeback_inodes_sb() directly, because it
2121	 * will emit a warning if sb->s_umount is not locked.
2122	 */
2123	if (btrfs_test_opt(fs_info, FLUSHONCOMMIT))
2124		try_to_writeback_inodes_sb(fs_info->sb, WB_REASON_SYNC);
2125	return 0;
2126}
2127
2128static inline void btrfs_wait_delalloc_flush(struct btrfs_fs_info *fs_info)
2129{
2130	if (btrfs_test_opt(fs_info, FLUSHONCOMMIT))
2131		btrfs_wait_ordered_roots(fs_info, U64_MAX, NULL);
2132}
2133
2134/*
2135 * Add a pending snapshot associated with the given transaction handle to the
2136 * respective handle. This must be called after the transaction commit started
2137 * and while holding fs_info->trans_lock.
2138 * This serves to guarantee a caller of btrfs_commit_transaction() that it can
2139 * safely free the pending snapshot pointer in case btrfs_commit_transaction()
2140 * returns an error.
2141 */
2142static void add_pending_snapshot(struct btrfs_trans_handle *trans)
2143{
2144	struct btrfs_transaction *cur_trans = trans->transaction;
2145
2146	if (!trans->pending_snapshot)
2147		return;
2148
2149	lockdep_assert_held(&trans->fs_info->trans_lock);
2150	ASSERT(cur_trans->state >= TRANS_STATE_COMMIT_PREP);
2151
2152	list_add(&trans->pending_snapshot->list, &cur_trans->pending_snapshots);
2153}
2154
2155static void update_commit_stats(struct btrfs_fs_info *fs_info, ktime_t interval)
 
2156{
2157	fs_info->commit_stats.commit_count++;
2158	fs_info->commit_stats.last_commit_dur = interval;
2159	fs_info->commit_stats.max_commit_dur =
2160			max_t(u64, fs_info->commit_stats.max_commit_dur, interval);
2161	fs_info->commit_stats.total_commit_dur += interval;
2162}
2163
2164int btrfs_commit_transaction(struct btrfs_trans_handle *trans)
2165{
2166	struct btrfs_fs_info *fs_info = trans->fs_info;
2167	struct btrfs_transaction *cur_trans = trans->transaction;
2168	struct btrfs_transaction *prev_trans = NULL;
2169	int ret;
2170	ktime_t start_time;
2171	ktime_t interval;
2172
2173	ASSERT(refcount_read(&trans->use_count) == 1);
2174	btrfs_trans_state_lockdep_acquire(fs_info, BTRFS_LOCKDEP_TRANS_COMMIT_PREP);
2175
2176	clear_bit(BTRFS_FS_NEED_TRANS_COMMIT, &fs_info->flags);
2177
2178	/* Stop the commit early if ->aborted is set */
2179	if (TRANS_ABORTED(cur_trans)) {
2180		ret = cur_trans->aborted;
2181		goto lockdep_trans_commit_start_release;
 
2182	}
2183
2184	btrfs_trans_release_metadata(trans);
 
 
 
 
 
 
 
 
 
2185	trans->block_rsv = NULL;
2186
 
 
2187	/*
2188	 * We only want one transaction commit doing the flushing so we do not
2189	 * waste a bunch of time on lock contention on the extent root node.
2190	 */
2191	if (!test_and_set_bit(BTRFS_DELAYED_REFS_FLUSHING,
2192			      &cur_trans->delayed_refs.flags)) {
2193		/*
2194		 * Make a pass through all the delayed refs we have so far.
2195		 * Any running threads may add more while we are here.
2196		 */
2197		ret = btrfs_run_delayed_refs(trans, 0);
2198		if (ret)
2199			goto lockdep_trans_commit_start_release;
2200	}
2201
2202	btrfs_create_pending_block_groups(trans);
 
 
 
 
 
 
 
2203
2204	if (!test_bit(BTRFS_TRANS_DIRTY_BG_RUN, &cur_trans->flags)) {
2205		int run_it = 0;
2206
2207		/* this mutex is also taken before trying to set
2208		 * block groups readonly.  We need to make sure
2209		 * that nobody has set a block group readonly
2210		 * after a extents from that block group have been
2211		 * allocated for cache files.  btrfs_set_block_group_ro
2212		 * will wait for the transaction to commit if it
2213		 * finds BTRFS_TRANS_DIRTY_BG_RUN set.
2214		 *
2215		 * The BTRFS_TRANS_DIRTY_BG_RUN flag is also used to make sure
2216		 * only one process starts all the block group IO.  It wouldn't
2217		 * hurt to have more than one go through, but there's no
2218		 * real advantage to it either.
2219		 */
2220		mutex_lock(&fs_info->ro_block_group_mutex);
2221		if (!test_and_set_bit(BTRFS_TRANS_DIRTY_BG_RUN,
2222				      &cur_trans->flags))
2223			run_it = 1;
2224		mutex_unlock(&fs_info->ro_block_group_mutex);
2225
2226		if (run_it) {
2227			ret = btrfs_start_dirty_block_groups(trans);
2228			if (ret)
2229				goto lockdep_trans_commit_start_release;
2230		}
 
2231	}
2232
2233	spin_lock(&fs_info->trans_lock);
2234	if (cur_trans->state >= TRANS_STATE_COMMIT_PREP) {
2235		enum btrfs_trans_state want_state = TRANS_STATE_COMPLETED;
2236
2237		add_pending_snapshot(trans);
2238
2239		spin_unlock(&fs_info->trans_lock);
2240		refcount_inc(&cur_trans->use_count);
2241
2242		if (trans->in_fsync)
2243			want_state = TRANS_STATE_SUPER_COMMITTED;
2244
2245		btrfs_trans_state_lockdep_release(fs_info,
2246						  BTRFS_LOCKDEP_TRANS_COMMIT_PREP);
2247		ret = btrfs_end_transaction(trans);
2248		wait_for_commit(cur_trans, want_state);
2249
2250		if (TRANS_ABORTED(cur_trans))
 
 
2251			ret = cur_trans->aborted;
2252
2253		btrfs_put_transaction(cur_trans);
2254
2255		return ret;
2256	}
2257
2258	cur_trans->state = TRANS_STATE_COMMIT_PREP;
2259	wake_up(&fs_info->transaction_blocked_wait);
2260	btrfs_trans_state_lockdep_release(fs_info, BTRFS_LOCKDEP_TRANS_COMMIT_PREP);
2261
2262	if (cur_trans->list.prev != &fs_info->trans_list) {
2263		enum btrfs_trans_state want_state = TRANS_STATE_COMPLETED;
2264
2265		if (trans->in_fsync)
2266			want_state = TRANS_STATE_SUPER_COMMITTED;
2267
2268		prev_trans = list_entry(cur_trans->list.prev,
2269					struct btrfs_transaction, list);
2270		if (prev_trans->state < want_state) {
2271			refcount_inc(&prev_trans->use_count);
2272			spin_unlock(&fs_info->trans_lock);
2273
2274			wait_for_commit(prev_trans, want_state);
2275
2276			ret = READ_ONCE(prev_trans->aborted);
2277
2278			btrfs_put_transaction(prev_trans);
2279			if (ret)
2280				goto lockdep_release;
2281			spin_lock(&fs_info->trans_lock);
2282		}
2283	} else {
2284		/*
2285		 * The previous transaction was aborted and was already removed
2286		 * from the list of transactions at fs_info->trans_list. So we
2287		 * abort to prevent writing a new superblock that reflects a
2288		 * corrupt state (pointing to trees with unwritten nodes/leafs).
2289		 */
2290		if (BTRFS_FS_ERROR(fs_info)) {
2291			spin_unlock(&fs_info->trans_lock);
2292			ret = -EROFS;
2293			goto lockdep_release;
2294		}
 
 
2295	}
2296
2297	cur_trans->state = TRANS_STATE_COMMIT_START;
2298	wake_up(&fs_info->transaction_blocked_wait);
2299	spin_unlock(&fs_info->trans_lock);
2300
2301	/*
2302	 * Get the time spent on the work done by the commit thread and not
2303	 * the time spent waiting on a previous commit
2304	 */
2305	start_time = ktime_get_ns();
2306
2307	extwriter_counter_dec(cur_trans, trans->type);
2308
2309	ret = btrfs_start_delalloc_flush(fs_info);
2310	if (ret)
2311		goto lockdep_release;
2312
2313	ret = btrfs_run_delayed_items(trans);
2314	if (ret)
2315		goto lockdep_release;
2316
2317	/*
2318	 * The thread has started/joined the transaction thus it holds the
2319	 * lockdep map as a reader. It has to release it before acquiring the
2320	 * lockdep map as a writer.
2321	 */
2322	btrfs_lockdep_release(fs_info, btrfs_trans_num_extwriters);
2323	btrfs_might_wait_for_event(fs_info, btrfs_trans_num_extwriters);
2324	wait_event(cur_trans->writer_wait,
2325		   extwriter_counter_read(cur_trans) == 0);
2326
2327	/* some pending stuffs might be added after the previous flush. */
2328	ret = btrfs_run_delayed_items(trans);
2329	if (ret) {
2330		btrfs_lockdep_release(fs_info, btrfs_trans_num_writers);
2331		goto cleanup_transaction;
2332	}
2333
2334	btrfs_wait_delalloc_flush(fs_info);
2335
2336	/*
2337	 * Wait for all ordered extents started by a fast fsync that joined this
2338	 * transaction. Otherwise if this transaction commits before the ordered
2339	 * extents complete we lose logged data after a power failure.
2340	 */
2341	btrfs_might_wait_for_event(fs_info, btrfs_trans_pending_ordered);
2342	wait_event(cur_trans->pending_wait,
2343		   atomic_read(&cur_trans->pending_ordered) == 0);
2344
2345	btrfs_scrub_pause(fs_info);
2346	/*
2347	 * Ok now we need to make sure to block out any other joins while we
2348	 * commit the transaction.  We could have started a join before setting
2349	 * COMMIT_DOING so make sure to wait for num_writers to == 1 again.
2350	 */
2351	spin_lock(&fs_info->trans_lock);
2352	add_pending_snapshot(trans);
2353	cur_trans->state = TRANS_STATE_COMMIT_DOING;
2354	spin_unlock(&fs_info->trans_lock);
2355
2356	/*
2357	 * The thread has started/joined the transaction thus it holds the
2358	 * lockdep map as a reader. It has to release it before acquiring the
2359	 * lockdep map as a writer.
2360	 */
2361	btrfs_lockdep_release(fs_info, btrfs_trans_num_writers);
2362	btrfs_might_wait_for_event(fs_info, btrfs_trans_num_writers);
2363	wait_event(cur_trans->writer_wait,
2364		   atomic_read(&cur_trans->num_writers) == 1);
2365
2366	/*
2367	 * Make lockdep happy by acquiring the state locks after
2368	 * btrfs_trans_num_writers is released. If we acquired the state locks
2369	 * before releasing the btrfs_trans_num_writers lock then lockdep would
2370	 * complain because we did not follow the reverse order unlocking rule.
2371	 */
2372	btrfs_trans_state_lockdep_acquire(fs_info, BTRFS_LOCKDEP_TRANS_COMPLETED);
2373	btrfs_trans_state_lockdep_acquire(fs_info, BTRFS_LOCKDEP_TRANS_SUPER_COMMITTED);
2374	btrfs_trans_state_lockdep_acquire(fs_info, BTRFS_LOCKDEP_TRANS_UNBLOCKED);
2375
2376	/*
2377	 * We've started the commit, clear the flag in case we were triggered to
2378	 * do an async commit but somebody else started before the transaction
2379	 * kthread could do the work.
2380	 */
2381	clear_bit(BTRFS_FS_COMMIT_TRANS, &fs_info->flags);
2382
2383	if (TRANS_ABORTED(cur_trans)) {
2384		ret = cur_trans->aborted;
2385		btrfs_trans_state_lockdep_release(fs_info, BTRFS_LOCKDEP_TRANS_UNBLOCKED);
2386		goto scrub_continue;
2387	}
2388	/*
2389	 * the reloc mutex makes sure that we stop
2390	 * the balancing code from coming in and moving
2391	 * extents around in the middle of the commit
2392	 */
2393	mutex_lock(&fs_info->reloc_mutex);
2394
2395	/*
2396	 * We needn't worry about the delayed items because we will
2397	 * deal with them in create_pending_snapshot(), which is the
2398	 * core function of the snapshot creation.
2399	 */
2400	ret = create_pending_snapshots(trans);
2401	if (ret)
2402		goto unlock_reloc;
 
 
2403
2404	/*
2405	 * We insert the dir indexes of the snapshots and update the inode
2406	 * of the snapshots' parents after the snapshot creation, so there
2407	 * are some delayed items which are not dealt with. Now deal with
2408	 * them.
2409	 *
2410	 * We needn't worry that this operation will corrupt the snapshots,
2411	 * because all the tree which are snapshoted will be forced to COW
2412	 * the nodes and leaves.
2413	 */
2414	ret = btrfs_run_delayed_items(trans);
2415	if (ret)
2416		goto unlock_reloc;
 
 
2417
2418	ret = btrfs_run_delayed_refs(trans, U64_MAX);
2419	if (ret)
2420		goto unlock_reloc;
 
 
 
 
 
 
 
 
 
2421
2422	/*
2423	 * make sure none of the code above managed to slip in a
2424	 * delayed item
2425	 */
2426	btrfs_assert_delayed_root_empty(fs_info);
2427
2428	WARN_ON(cur_trans != trans->transaction);
2429
2430	ret = commit_fs_roots(trans);
2431	if (ret)
2432		goto unlock_reloc;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2433
2434	/* commit_fs_roots gets rid of all the tree log roots, it is now
2435	 * safe to free the root of tree log roots
2436	 */
2437	btrfs_free_log_root_tree(trans, fs_info);
2438
2439	/*
2440	 * Since fs roots are all committed, we can get a quite accurate
2441	 * new_roots. So let's do quota accounting.
2442	 */
2443	ret = btrfs_qgroup_account_extents(trans);
2444	if (ret < 0)
2445		goto unlock_reloc;
 
 
 
2446
2447	ret = commit_cowonly_roots(trans);
2448	if (ret)
2449		goto unlock_reloc;
 
 
 
2450
2451	/*
2452	 * The tasks which save the space cache and inode cache may also
2453	 * update ->aborted, check it.
2454	 */
2455	if (TRANS_ABORTED(cur_trans)) {
2456		ret = cur_trans->aborted;
2457		goto unlock_reloc;
 
 
2458	}
2459
 
 
2460	cur_trans = fs_info->running_transaction;
2461
2462	btrfs_set_root_node(&fs_info->tree_root->root_item,
2463			    fs_info->tree_root->node);
2464	list_add_tail(&fs_info->tree_root->dirty_list,
2465		      &cur_trans->switch_commits);
2466
2467	btrfs_set_root_node(&fs_info->chunk_root->root_item,
2468			    fs_info->chunk_root->node);
2469	list_add_tail(&fs_info->chunk_root->dirty_list,
2470		      &cur_trans->switch_commits);
2471
2472	if (btrfs_fs_incompat(fs_info, EXTENT_TREE_V2)) {
2473		btrfs_set_root_node(&fs_info->block_group_root->root_item,
2474				    fs_info->block_group_root->node);
2475		list_add_tail(&fs_info->block_group_root->dirty_list,
2476			      &cur_trans->switch_commits);
2477	}
2478
2479	switch_commit_roots(trans);
2480
 
2481	ASSERT(list_empty(&cur_trans->dirty_bgs));
2482	ASSERT(list_empty(&cur_trans->io_bgs));
2483	update_super_roots(fs_info);
2484
2485	btrfs_set_super_log_root(fs_info->super_copy, 0);
2486	btrfs_set_super_log_root_level(fs_info->super_copy, 0);
2487	memcpy(fs_info->super_for_commit, fs_info->super_copy,
2488	       sizeof(*fs_info->super_copy));
2489
2490	btrfs_commit_device_sizes(cur_trans);
 
2491
2492	clear_bit(BTRFS_FS_LOG1_ERR, &fs_info->flags);
2493	clear_bit(BTRFS_FS_LOG2_ERR, &fs_info->flags);
2494
2495	btrfs_trans_release_chunk_metadata(trans);
2496
2497	/*
2498	 * Before changing the transaction state to TRANS_STATE_UNBLOCKED and
2499	 * setting fs_info->running_transaction to NULL, lock tree_log_mutex to
2500	 * make sure that before we commit our superblock, no other task can
2501	 * start a new transaction and commit a log tree before we commit our
2502	 * superblock. Anyone trying to commit a log tree locks this mutex before
2503	 * writing its superblock.
2504	 */
2505	mutex_lock(&fs_info->tree_log_mutex);
2506
2507	spin_lock(&fs_info->trans_lock);
2508	cur_trans->state = TRANS_STATE_UNBLOCKED;
2509	fs_info->running_transaction = NULL;
2510	spin_unlock(&fs_info->trans_lock);
2511	mutex_unlock(&fs_info->reloc_mutex);
2512
2513	wake_up(&fs_info->transaction_wait);
2514	btrfs_trans_state_lockdep_release(fs_info, BTRFS_LOCKDEP_TRANS_UNBLOCKED);
2515
2516	/* If we have features changed, wake up the cleaner to update sysfs. */
2517	if (test_bit(BTRFS_FS_FEATURE_CHANGED, &fs_info->flags) &&
2518	    fs_info->cleaner_kthread)
2519		wake_up_process(fs_info->cleaner_kthread);
2520
2521	ret = btrfs_write_and_wait_transaction(trans);
2522	if (ret) {
2523		btrfs_handle_fs_error(fs_info, ret,
2524				      "Error while writing out transaction");
2525		mutex_unlock(&fs_info->tree_log_mutex);
2526		goto scrub_continue;
2527	}
2528
2529	ret = write_all_supers(fs_info, 0);
 
 
 
 
 
2530	/*
2531	 * the super is written, we can safely allow the tree-loggers
2532	 * to go about their business
2533	 */
2534	mutex_unlock(&fs_info->tree_log_mutex);
2535	if (ret)
2536		goto scrub_continue;
2537
2538	/*
2539	 * We needn't acquire the lock here because there is no other task
2540	 * which can change it.
2541	 */
2542	cur_trans->state = TRANS_STATE_SUPER_COMMITTED;
2543	wake_up(&cur_trans->commit_wait);
2544	btrfs_trans_state_lockdep_release(fs_info, BTRFS_LOCKDEP_TRANS_SUPER_COMMITTED);
2545
2546	btrfs_finish_extent_commit(trans);
2547
2548	if (test_bit(BTRFS_TRANS_HAVE_FREE_BGS, &cur_trans->flags))
2549		btrfs_clear_space_info_full(fs_info);
2550
2551	btrfs_set_last_trans_committed(fs_info, cur_trans->transid);
2552	/*
2553	 * We needn't acquire the lock here because there is no other task
2554	 * which can change it.
2555	 */
2556	cur_trans->state = TRANS_STATE_COMPLETED;
2557	wake_up(&cur_trans->commit_wait);
2558	btrfs_trans_state_lockdep_release(fs_info, BTRFS_LOCKDEP_TRANS_COMPLETED);
2559
2560	spin_lock(&fs_info->trans_lock);
2561	list_del_init(&cur_trans->list);
2562	spin_unlock(&fs_info->trans_lock);
2563
2564	btrfs_put_transaction(cur_trans);
2565	btrfs_put_transaction(cur_trans);
2566
2567	if (trans->type & __TRANS_FREEZABLE)
2568		sb_end_intwrite(fs_info->sb);
2569
2570	trace_btrfs_transaction_commit(fs_info);
2571
2572	interval = ktime_get_ns() - start_time;
2573
2574	btrfs_scrub_continue(fs_info);
2575
2576	if (current->journal_info == trans)
2577		current->journal_info = NULL;
2578
2579	kmem_cache_free(btrfs_trans_handle_cachep, trans);
2580
2581	update_commit_stats(fs_info, interval);
 
 
 
 
 
 
2582
2583	return ret;
2584
2585unlock_reloc:
2586	mutex_unlock(&fs_info->reloc_mutex);
2587	btrfs_trans_state_lockdep_release(fs_info, BTRFS_LOCKDEP_TRANS_UNBLOCKED);
2588scrub_continue:
2589	btrfs_trans_state_lockdep_release(fs_info, BTRFS_LOCKDEP_TRANS_SUPER_COMMITTED);
2590	btrfs_trans_state_lockdep_release(fs_info, BTRFS_LOCKDEP_TRANS_COMPLETED);
2591	btrfs_scrub_continue(fs_info);
2592cleanup_transaction:
2593	btrfs_trans_release_metadata(trans);
2594	btrfs_cleanup_pending_block_groups(trans);
2595	btrfs_trans_release_chunk_metadata(trans);
2596	trans->block_rsv = NULL;
2597	btrfs_warn(fs_info, "Skipping commit of aborted transaction.");
2598	if (current->journal_info == trans)
2599		current->journal_info = NULL;
2600	cleanup_transaction(trans, ret);
2601
2602	return ret;
2603
2604lockdep_release:
2605	btrfs_lockdep_release(fs_info, btrfs_trans_num_extwriters);
2606	btrfs_lockdep_release(fs_info, btrfs_trans_num_writers);
2607	goto cleanup_transaction;
2608
2609lockdep_trans_commit_start_release:
2610	btrfs_trans_state_lockdep_release(fs_info, BTRFS_LOCKDEP_TRANS_COMMIT_PREP);
2611	btrfs_end_transaction(trans);
2612	return ret;
2613}
2614
2615/*
2616 * return < 0 if error
2617 * 0 if there are no more dead_roots at the time of call
2618 * 1 there are more to be processed, call me again
2619 *
2620 * The return value indicates there are certainly more snapshots to delete, but
2621 * if there comes a new one during processing, it may return 0. We don't mind,
2622 * because btrfs_commit_super will poke cleaner thread and it will process it a
2623 * few seconds later.
2624 */
2625int btrfs_clean_one_deleted_snapshot(struct btrfs_fs_info *fs_info)
2626{
2627	struct btrfs_root *root;
2628	int ret;
 
2629
2630	spin_lock(&fs_info->trans_lock);
2631	if (list_empty(&fs_info->dead_roots)) {
2632		spin_unlock(&fs_info->trans_lock);
2633		return 0;
2634	}
2635	root = list_first_entry(&fs_info->dead_roots,
2636			struct btrfs_root, root_list);
2637	list_del_init(&root->root_list);
2638	spin_unlock(&fs_info->trans_lock);
2639
2640	btrfs_debug(fs_info, "cleaner removing %llu", btrfs_root_id(root));
2641
2642	btrfs_kill_all_delayed_nodes(root);
2643
2644	if (btrfs_header_backref_rev(root->node) <
2645			BTRFS_MIXED_BACKREF_REV)
2646		ret = btrfs_drop_snapshot(root, 0, 0);
2647	else
2648		ret = btrfs_drop_snapshot(root, 1, 0);
2649
2650	btrfs_put_root(root);
2651	return (ret < 0) ? 0 : 1;
2652}
2653
2654/*
2655 * We only mark the transaction aborted and then set the file system read-only.
2656 * This will prevent new transactions from starting or trying to join this
2657 * one.
2658 *
2659 * This means that error recovery at the call site is limited to freeing
2660 * any local memory allocations and passing the error code up without
2661 * further cleanup. The transaction should complete as it normally would
2662 * in the call path but will return -EIO.
2663 *
2664 * We'll complete the cleanup in btrfs_end_transaction and
2665 * btrfs_commit_transaction.
2666 */
2667void __cold __btrfs_abort_transaction(struct btrfs_trans_handle *trans,
2668				      const char *function,
2669				      unsigned int line, int error, bool first_hit)
2670{
2671	struct btrfs_fs_info *fs_info = trans->fs_info;
 
2672
2673	WRITE_ONCE(trans->aborted, error);
2674	WRITE_ONCE(trans->transaction->aborted, error);
2675	if (first_hit && error == -ENOSPC)
2676		btrfs_dump_space_info_for_trans_abort(fs_info);
2677	/* Wake up anybody who may be waiting on this transaction */
2678	wake_up(&fs_info->transaction_wait);
2679	wake_up(&fs_info->transaction_blocked_wait);
2680	__btrfs_handle_fs_error(fs_info, function, line, error, NULL);
2681}
2682
2683int __init btrfs_transaction_init(void)
2684{
2685	btrfs_trans_handle_cachep = KMEM_CACHE(btrfs_trans_handle, SLAB_TEMPORARY);
2686	if (!btrfs_trans_handle_cachep)
2687		return -ENOMEM;
2688	return 0;
2689}
2690
2691void __cold btrfs_transaction_exit(void)
2692{
2693	kmem_cache_destroy(btrfs_trans_handle_cachep);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2694}