Commit b666a9cd authored by David Sterba's avatar David Sterba
Browse files

btrfs: add barrier for waitqueue_active in clear_btree_io_tree 



waitqueue_active should be preceded by a barrier, in this function we
don't need to call it all the time.

Signed-off-by: default avatarDavid Sterba <dsterba@suse.com>
parent 730d9ec3

fs/btrfs/transaction.c

+6 −0
Original line number Diff line number Diff line
@@ -82,6 +82,12 @@ void btrfs_put_transaction(struct btrfs_transaction *transaction) 
static void clear_btree_io_tree(struct extent_io_tree *tree)

{

	spin_lock(&tree->lock);

	/*

	 * Do a single barrier for the waitqueue_active check here, the state

	 * of the waitqueue should not change once clear_btree_io_tree is

	 * called.

	 */

	smp_mb();

	while (!RB_EMPTY_ROOT(&tree->state)) {

		struct rb_node *node;

		struct extent_state *state;