diff --git a/sys/fs/msdosfs/msdosfs_vfsops.c b/sys/fs/msdosfs/msdosfs_vfsops.c
index d14cdef51a75..11659349357b 100644
--- a/sys/fs/msdosfs/msdosfs_vfsops.c
+++ b/sys/fs/msdosfs/msdosfs_vfsops.c
@@ -796,17 +796,17 @@ msdosfs_unmount(struct mount *mp, int mntflags)
 	struct msdosfsmount *pmp;
 	int error, flags;
 
-	flags = 0;
-	error = msdosfs_sync(mp, MNT_WAIT);
-	if ((mntflags & MNT_FORCE) != 0) {
+	error = flags = 0;
+	pmp = VFSTOMSDOSFS(mp);
+	if ((pmp->pm_flags & MSDOSFSMNT_RONLY) == 0)
+		error = msdosfs_sync(mp, MNT_WAIT);
+	if ((mntflags & MNT_FORCE) != 0)
 		flags |= FORCECLOSE;
-	} else if (error != 0) {
+	else if (error != 0)
 		return (error);
-	}
 	error = vflush(mp, 0, flags, curthread);
 	if (error != 0 && error != ENXIO)
 		return (error);
-	pmp = VFSTOMSDOSFS(mp);
 	if ((pmp->pm_flags & MSDOSFSMNT_RONLY) == 0) {
 		error = markvoldirty(pmp, 0);
 		if (error && error != ENXIO) {