dm raid: fix compat_features validation

In ecbfb9f118bce4 ("dm raid: add raid level takeover support") a new
compatible feature flag was added.  Validation for these compat_features
was added but this only passes for new raid mappings with this feature
flag.  This causes previously created raid mappings to be failed at
import.

Check compat_features for the only valid combination.

Fixes: ecbfb9f118bce4 ("dm raid: add raid level takeover support")
Cc: stable@vger.kernel.org # v4.8
Signed-off-by: Andy Whitcroft <apw@canonical.com>
Signed-off-by: Heinz Mauelshagen <heinzm@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>

diff --git a/drivers/md/dm-raid.c b/drivers/md/dm-raid.c
index 8abde6b8cedc4540dac80b73256317fb671dbd69..2a397009799100d481c7d8815ac95d45fdb0eb2d 100644 (file)
--- a/drivers/md/dm-raid.c
+++ b/drivers/md/dm-raid.c
@@ -2258,7 +2258,8 @@ static int super_validate(struct raid_set *rs, struct md_rdev *rdev)
        if (!mddev->events && super_init_validation(rs, rdev))
                return -EINVAL;
 
-       if (le32_to_cpu(sb->compat_features) != FEATURE_FLAG_SUPPORTS_V190) {
+       if (le32_to_cpu(sb->compat_features) &&
+           le32_to_cpu(sb->compat_features) != FEATURE_FLAG_SUPPORTS_V190) {
                rs->ti->error = "Unable to assemble array: Unknown flag(s) in compatible feature flags";
                return -EINVAL;
        }