From: Trond Myklebust <trond.myklebust@primarydata.com>
Date: Fri, 3 Nov 2017 08:00:15 -0400
Subject: [PATCH] nfsd: Ensure we check stateid validity in the seqid operation
 checks
Git-commit: 9271d7e509c1bfc0b9a418caec29ec8d1ac38270
Patch-mainline: v4.15
References: git-fixes

After taking the stateid st_mutex, we want to know that the stateid
still represents valid state before performing any non-idempotent
actions.

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Acked-by: NeilBrown <neilb@suse.com>

---
 fs/nfsd/nfs4state.c |   12 +++---------
 1 file changed, 3 insertions(+), 9 deletions(-)

--- a/fs/nfsd/nfs4state.c
+++ b/fs/nfsd/nfs4state.c
@@ -5205,15 +5205,9 @@ static __be32 nfs4_seqid_op_checks(struc
 	status = nfsd4_check_seqid(cstate, sop, seqid);
 	if (status)
 		return status;
-	if (stp->st_stid.sc_type == NFS4_CLOSED_STID
-		|| stp->st_stid.sc_type == NFS4_REVOKED_DELEG_STID)
-		/*
-		 * "Closed" stateid's exist *only* to return
-		 * nfserr_replay_me from the previous step, and
-		 * revoked delegations are kept only for free_stateid.
-		 */
-		return nfserr_bad_stateid;
-	mutex_lock(&stp->st_mutex);
+	status = nfsd4_lock_ol_stateid(stp);
+	if (status != nfs_ok)
+		return status;
 	status = check_stateid_generation(stateid, &stp->st_stid.sc_stateid, nfsd4_has_session(cstate));
 	if (status == nfs_ok)
 		status = nfs4_check_fh(current_fh, &stp->st_stid);