tree f4bbb063b81ba920fffe16fd12bfc0d01db05673
parent 066715d3fde4834cbbec88d12ca277c4185b9303
author Al Viro <viro@zeniv.linux.org.uk> 1479688389 -0500
committer Al Viro <viro@zeniv.linux.org.uk> 1481923849 -0500

reorganize do_make_slave()

Make sure that clone_mnt() never returns a mount with MNT_SHARED in
flags, but without a valid ->mnt_group_id.  That allows to demystify
do_make_slave() quite a bit, among other things.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>