stable inclusion
from linux-4.19.169
commit df7adeee7477c865fecdd43b55aee6cca0e9bb0a

--------------------------------

commit 896567ee upstream.

Before referencing the inode, we must ensure that the superblock can be
referenced. Otherwise, we can end up with iput() calling superblock
operations that are no longer valid or accessible.

Fixes: ea7c38fe ("NFSv4: Ensure we reference the inode for return-on-close in delegreturn")
Signed-off-by: NTrond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: NYang Yingliang <yangyingliang@huawei.com>
Signed-off-by: NCheng Jian <cj.chengjian@huawei.com>