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 <[email protected]> --- fs/btrfs/ctree.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/fs/btrfs/ctree.c b/fs/btrfs/ctree.c index b88a79e69ddf..4c75df2eea2e 100644 --- a/fs/btrfs/ctree.c +++ b/fs/btrfs/ctree.c @@ -1502,8 +1502,8 @@ 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 -- 2.16.2 -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
