gfs2: Fix glock rhashtable rcu bug (961ae1d8) · Commits · 戴 / test

Before commit "GFS2: Use resizable hash table for glocks", glocks were freed via call_rcu to allow reading the glock hashtable locklessly using rcu. This was then changed to free glocks immediately, which made reading the glock hashtable unsafe. Bring back the original code for freeing glocks via call_rcu. Signed-off-by:

Andreas Gruenbacher <agruenba@redhat.com> Signed-off-by:

Bob Peterson <rpeterso@redhat.com> Cc: stable@vger.kernel.org # 4.3+

fs/gfs2/glock.c

+9 −2

Original line number	Diff line number	Diff line
		@@ -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);
		}

fs/gfs2/incore.h

+1 −0

Original line number	Diff line number	Diff line
		@@ -373,6 +373,7 @@ struct gfs2_glock {
		loff_t end;
		} gl_vm;
		};
		struct rcu_head gl_rcu;
		struct rhash_head gl_node;
		};

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