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Commit 48ec2cf8 authored by Chris Mason's avatar Chris Mason
Browse files

Btrfs: Fix race in running_transaction checks 



When a new transaction was started, the code would incorrectly
set the pointer in fs_info before all the data structures were setup.
fsync heavy workloads hit races on the setup of the ordered inode spinlock

Signed-off-by: default avatarChris Mason <chris.mason@oracle.com>
parent e1b81e67

fs/btrfs/transaction.c

+3 −1
Original line number Diff line number Diff line
@@ -56,7 +56,6 @@ static noinline int join_transaction(struct btrfs_root *root) 
		total_trans++;

		BUG_ON(!cur_trans);

		root->fs_info->generation++;

		root->fs_info->running_transaction = cur_trans;

		root->fs_info->last_alloc = 0;

		root->fs_info->last_data_alloc = 0;

		cur_trans->num_writers = 1;
@@ -74,6 +73,9 @@ static noinline int join_transaction(struct btrfs_root *root) 
		extent_io_tree_init(&cur_trans->dirty_pages,

				     root->fs_info->btree_inode->i_mapping,

				     GFP_NOFS);

		spin_lock(&root->fs_info->new_trans_lock);

		root->fs_info->running_transaction = cur_trans;

		spin_unlock(&root->fs_info->new_trans_lock);

	} else {

		cur_trans->num_writers++;

		cur_trans->num_joined++;