GFS2: Fix glock deallocation race

This patch fixes a race in deallocating glocks which was introduced
in the RCU glock patch. We need to ensure that the glock count is
kept correct even in the case that there is a race to add a new
glock into the hash table. Also, to avoid having to wait for an
RCU grace period, the glock counter can be decremented before
call_rcu() is called.

Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>

1 files changed, 1 insertions, 6 deletions

diff --git a/fs/gfs2/ops_fstype.c b/fs/gfs2/ops_fstype.c
index a39c103..67654d0 100644
--- a/fs/gfs2/ops_fstype.c
+++ b/fs/gfs2/ops_fstype.c
@@ -928,14 +928,9 @@ static const match_table_t nolock_tokens = {
 	{ Opt_err, NULL },
 };
 
-static void nolock_put_lock(struct gfs2_glock *gl)
-{
-	call_rcu(&gl->gl_rcu, gfs2_glock_free);
-}
-
 static const struct lm_lockops nolock_ops = {
 	.lm_proto_name = "lock_nolock",
-	.lm_put_lock = nolock_put_lock,
+	.lm_put_lock = gfs2_glock_free,
 	.lm_tokens = &nolock_tokens,
 };