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Commit 6cf7f77e authored by Wang Shilong's avatar Wang Shilong Committed by Josef Bacik
Browse files

Btrfs: fix a possible deadlock between scrub and transaction committing 



btrfs_scrub_continue() will be called when cleaning up transaction.However,
this can only be called if btrfs_scrub_pause() is called before.

Signed-off-by: default avatarWang Shilong <wangsl.fnst@cn.fujitsu.com>
Signed-off-by: default avatarJosef Bacik <jbacik@fb.com>
parent 886322e8

fs/btrfs/transaction.c

+11 −11
Original line number Diff line number Diff line
@@ -1578,8 +1578,6 @@ static void cleanup_transaction(struct btrfs_trans_handle *trans, 


	trace_btrfs_transaction_commit(root);



	btrfs_scrub_continue(root);



	if (current->journal_info == trans)

		current->journal_info = NULL;
@@ -1754,7 +1752,7 @@ int btrfs_commit_transaction(struct btrfs_trans_handle *trans, 
	/* ->aborted might be set after the previous check, so check it */

	if (unlikely(ACCESS_ONCE(cur_trans->aborted))) {

		ret = cur_trans->aborted;

		goto cleanup_transaction;

		goto scrub_continue;

	}

	/*

	 * the reloc mutex makes sure that we stop
@@ -1771,7 +1769,7 @@ int btrfs_commit_transaction(struct btrfs_trans_handle *trans, 
	ret = create_pending_snapshots(trans, root->fs_info);

	if (ret) {

		mutex_unlock(&root->fs_info->reloc_mutex);

		goto cleanup_transaction;

		goto scrub_continue;

	}



	/*
@@ -1787,13 +1785,13 @@ int btrfs_commit_transaction(struct btrfs_trans_handle *trans, 
	ret = btrfs_run_delayed_items(trans, root);

	if (ret) {

		mutex_unlock(&root->fs_info->reloc_mutex);

		goto cleanup_transaction;

		goto scrub_continue;

	}



	ret = btrfs_run_delayed_refs(trans, root, (unsigned long)-1);

	if (ret) {

		mutex_unlock(&root->fs_info->reloc_mutex);

		goto cleanup_transaction;

		goto scrub_continue;

	}



	/*
@@ -1823,7 +1821,7 @@ int btrfs_commit_transaction(struct btrfs_trans_handle *trans, 
	if (ret) {

		mutex_unlock(&root->fs_info->tree_log_mutex);

		mutex_unlock(&root->fs_info->reloc_mutex);

		goto cleanup_transaction;

		goto scrub_continue;

	}



	/*
@@ -1844,7 +1842,7 @@ int btrfs_commit_transaction(struct btrfs_trans_handle *trans, 
	if (ret) {

		mutex_unlock(&root->fs_info->tree_log_mutex);

		mutex_unlock(&root->fs_info->reloc_mutex);

		goto cleanup_transaction;

		goto scrub_continue;

	}



	/*
@@ -1855,7 +1853,7 @@ int btrfs_commit_transaction(struct btrfs_trans_handle *trans, 
		ret = cur_trans->aborted;

		mutex_unlock(&root->fs_info->tree_log_mutex);

		mutex_unlock(&root->fs_info->reloc_mutex);

		goto cleanup_transaction;

		goto scrub_continue;

	}



	btrfs_prepare_extent_commit(trans, root);
@@ -1891,13 +1889,13 @@ int btrfs_commit_transaction(struct btrfs_trans_handle *trans, 
		btrfs_error(root->fs_info, ret,

			    "Error while writing out transaction");

		mutex_unlock(&root->fs_info->tree_log_mutex);

		goto cleanup_transaction;

		goto scrub_continue;

	}



	ret = write_ctree_super(trans, root, 0);

	if (ret) {

		mutex_unlock(&root->fs_info->tree_log_mutex);

		goto cleanup_transaction;

		goto scrub_continue;

	}



	/*
@@ -1940,6 +1938,8 @@ int btrfs_commit_transaction(struct btrfs_trans_handle *trans, 


	return ret;



scrub_continue:

	btrfs_scrub_continue(root);

cleanup_transaction:

	btrfs_trans_release_metadata(trans, root);

	trans->block_rsv = NULL;