Merge tag 'gfs2-4.13.fixes.addendum' of git://git.kernel.org/pub/scm/linux/kernel/git/gfs2/linux-gfs2

Pull GFS2 fix from Bob Peterson:
 "Sorry for the additional merge request, but Andreas discovered this
  problem soon after you processed our last gfs2 merge.

  This fixes a regression introduced by a patch we did in mid-2015
  (commit 88ffbf3e037e: "GFS2: Use resizable hash table for glocks"), so
  best to get it fixed. Some code was reverted that should not have
  been.

  The patch from Andreas Gruenbacher just re-adds code that had been
  there originally"

* tag 'gfs2-4.13.fixes.addendum' of git://git.kernel.org/pub/scm/linux/kernel/git/gfs2/linux-gfs2:
  gfs2: Fix glock rhashtable rcu bug

2 files changed, 10 insertions, 2 deletions

diff --git a/fs/gfs2/glock.c b/fs/gfs2/glock.c
index 6cd71c50b8bdc7..c38ab6c8189838 100644
--- a/fs/gfs2/glock.c
+++ b/fs/gfs2/glock.c
@@ -80,9 +80,9 @@ static struct rhashtable_params ht_parms = {
 
 static struct rhashtable gl_hash_table;
 
-void gfs2_glock_free(struct gfs2_glock *gl)
+static void gfs2_glock_dealloc(struct rcu_head *rcu)
 {
-	struct gfs2_sbd *sdp = gl->gl_name.ln_sbd;
+	struct gfs2_glock *gl = container_of(rcu, struct gfs2_glock, gl_rcu);
 
 	if (gl->gl_ops->go_flags & GLOF_ASPACE) {
 		kmem_cache_free(gfs2_glock_aspace_cachep, gl);
@@ -90,6 +90,13 @@ void gfs2_glock_free(struct gfs2_glock *gl)
 		kfree(gl->gl_lksb.sb_lvbptr);
 		kmem_cache_free(gfs2_glock_cachep, gl);
 	}
+}
+
+void gfs2_glock_free(struct gfs2_glock *gl)
+{
+	struct gfs2_sbd *sdp = gl->gl_name.ln_sbd;
+
+	call_rcu(&gl->gl_rcu, gfs2_glock_dealloc);
 	if (atomic_dec_and_test(&sdp->sd_glock_disposal))
 		wake_up(&sdp->sd_glock_wait);
 }
diff --git a/fs/gfs2/incore.h b/fs/gfs2/incore.h
index 790e7398428877..73fce76e67ee84 100644
--- a/fs/gfs2/incore.h
+++ b/fs/gfs2/incore.h
@@ -373,6 +373,7 @@ struct gfs2_glock {
 			loff_t end;
 		} gl_vm;
 	};
+	struct rcu_head gl_rcu;
 	struct rhash_head gl_node;
 };