unionfs: fix suspendability check bugs

- MNTK_SUSPENDABLE is set in mnt_kern_flag, not mnt_flag.
- The lower layer of a unionfs mount is read-only, so the mount should
  be suspendable iff the upper layer is suspendable.
- Remove a couple of superfluous comments.

Differential Revision:	https://reviews.freebsd.org/D2714
Reviewed by:	kib, mjg

1 files changed, 1 insertions, 8 deletions

diff --git a/sys/fs/unionfs/union_vfsops.c b/sys/fs/unionfs/union_vfsops.c
index e4b9fb5..f65ee8c 100644
--- a/sys/fs/unionfs/union_vfsops.c
+++ b/sys/fs/unionfs/union_vfsops.c
@@ -291,18 +291,11 @@ unionfs_domount(struct mount *mp)
 	}
 
 	MNT_ILOCK(mp);
-	/*
-	 * Check mnt_flag
-	 */
 	if ((ump->um_lowervp->v_mount->mnt_flag & MNT_LOCAL) &&
 	    (ump->um_uppervp->v_mount->mnt_flag & MNT_LOCAL))
 		mp->mnt_flag |= MNT_LOCAL;
 
-	/*
-	 * Check mnt_kern_flag
-	 */
-	if ((ump->um_lowervp->v_mount->mnt_flag & MNTK_SUSPENDABLE) ||
-	    (ump->um_uppervp->v_mount->mnt_flag & MNTK_SUSPENDABLE))
+	if ((ump->um_uppervp->v_mount->mnt_kern_flag & MNTK_SUSPENDABLE) != 0)
 		mp->mnt_kern_flag |= MNTK_SUSPENDABLE;
 	MNT_IUNLOCK(mp);