From: Jeff Layton <jlayton@redhat.com>
Date: Wed, 28 Jan 2009 12:53:26 -0500
Subject: [nfs] only set file_lock.fl_lmops if stateowner is found
Message-id: 1233165206-31117-4-git-send-email-jlayton@redhat.com
O-Subject: [RHEL5.4 PATCH 3/3] BZ#479323: nfsd: only set file_lock.fl_lmops in nfsd4_lockt if a stateowner is found
Bugzilla: 479323
RH-Acked-by: Peter Staubach <staubach@redhat.com>

nfsd4_lockt does a search for a lockstateowner when building the lock
struct to test. If one is found, it'll set fl_owner to it. Regardless of
whether that happens, it'll also set fl_lmops. Given that this lock is
basically a "lightweight" lock that's just used for checking conflicts,
setting fl_lmops is probably not appropriate for it.

This behavior exposed a bug in DLM's GETLK implementation where it
wasn't clearing out the fields in the file_lock before filling in
conflicting lock info. While we were able to fix this in DLM, it
still seems pointless and dangerous to set the fl_lmops this way
when we may have a NULL lockstateowner.

Signed-off-by: Jeff Layton <jlayton@redhat.com>

diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
index e9da094..a6489a4 100644
--- a/fs/nfsd/nfs4state.c
+++ b/fs/nfsd/nfs4state.c
@@ -2869,7 +2869,6 @@ nfsd4_lockt(struct svc_rqst *rqstp, struct svc_fh *current_fh, struct nfsd4_lock
 		file_lock.fl_owner = (fl_owner_t)lockt->lt_stateowner;
 	file_lock.fl_pid = current->tgid;
 	file_lock.fl_flags = FL_POSIX;
-	file_lock.fl_lmops = &nfsd_posix_mng_ops;
 
 	file_lock.fl_start = lockt->lt_offset;
 	if ((lockt->lt_length == ~(u64)0) || LOFF_OVERFLOW(lockt->lt_offset, lockt->lt_length))