tree 751e0f4816c925be1ef25452e32a1cd55b325f35
parent c251267c8826027af32fe7195650d29797539847
author Trond Myklebust <trond.myklebust@primarydata.com> 1509710410 -0400
committer Greg Kroah-Hartman <gregkh@linuxfoundation.org> 1512469472 +0100

nfsd: Fix stateid races between OPEN and CLOSE

commit 15ca08d3299682dc49bad73251677b2c5017ef08 upstream.

Open file stateids can linger on the nfs4_file list of stateids even
after they have been closed. In order to avoid reusing such a
stateid, and confusing the client, we need to recheck the
nfs4_stid's type after taking the mutex.
Otherwise, we risk reusing an old stateid that was already closed,
which will confuse clients that expect new stateids to conform to
RFC7530 Sections 9.1.4.2 and 16.2.5 or RFC5661 Sections 8.2.2 and 18.2.4.

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>