[ Upstream commit 5808b14a1f52554de612fee85ef517199855e310 ]

Fix a use-after-free bug during filesystem initialisation, where we
access the disc record (which is stored in a buffer) after we have
released the buffer.
Signed-off-by: NRussell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
Signed-off-by: NSasha Levin <sashal@kernel.org>
Signed-off-by: NYang Yingliang <yangyingliang@huawei.com>