mnt_flags fixes in do_remount()

* need vfsmount_lock over modifying it
* need to preserve MNT_SHARED/MNT_UNBINDABLE

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This commit is contained in:
Al Viro 2010-01-16 13:01:26 -05:00
commit 7b43a79f32