Commit d1980131 authored Mar 16, 2018 by David Sterba

btrfs: update barrier in should_cow_block



Once there was a simple int force_cow that was used with the plain
barriers, and then converted to a bit, so we should use the appropriate
barrier helper.

Other variables in the complex if condition do not depend on a barrier,
so we should be fine in case the atomic barrier becomes a no-op.

Signed-off-by: David Sterba <dsterba@suse.com>

parent a32bf9a3

fs/btrfs/ctree.c

+2 −2

Original line number	Diff line number	Diff line
		@@ -1441,8 +1441,8 @@ static inline int should_cow_block(struct btrfs_trans_handle *trans,
		if (btrfs_is_testing(root->fs_info))
		return 0;

		/* ensure we can see the force_cow */
		smp_rmb();
		/* Ensure we can see the FORCE_COW bit */
		smp_mb__before_atomic();

		/*
		* We do not need to cow a block if