releases/2.6.27.15/dlm-initialize-file_lock-struct-in-getlk-before-copying-conflicting-lock.patch

From 20d5a39929232a715f29e6cb7e3f0d0c790f41eb Mon Sep 17 00:00:00 2001
From: Jeff Layton <jlayton@redhat.com>
Date: Wed, 21 Jan 2009 11:34:50 -0500
Subject: dlm: initialize file_lock struct in GETLK before copying conflicting lock

From: Jeff Layton <jlayton@redhat.com>

commit 20d5a39929232a715f29e6cb7e3f0d0c790f41eb upstream.

dlm_posix_get fills out the relevant fields in the file_lock before
returning when there is a lock conflict, but doesn't clean out any of
the other fields in the file_lock.

When nfsd does a NFSv4 lockt call, it sets the fl_lmops to
nfsd_posix_mng_ops before calling the lower fs. When the lock comes back
after testing a lock on GFS2, it still has that field set. This confuses
nfsd into thinking that the file_lock is a nfsd4 lock.

Fix this by making DLM reinitialize the file_lock before copying the
fields from the conflicting lock.

Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: David Teigland <teigland@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

---
 fs/dlm/plock.c |    2 ++
 1 file changed, 2 insertions(+)

--- a/fs/dlm/plock.c
+++ b/fs/dlm/plock.c
@@ -304,7 +304,9 @@ int dlm_posix_get(dlm_lockspace_t *locks
 	if (rv == -ENOENT)
 		rv = 0;
 	else if (rv > 0) {
+		locks_init_lock(fl);
 		fl->fl_type = (op->info.ex) ? F_WRLCK : F_RDLCK;
+		fl->fl_flags = FL_POSIX;
 		fl->fl_pid = op->info.pid;
 		fl->fl_start = op->info.start;
 		fl->fl_end = op->info.end;