Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 4cf918c8 authored by Andrew Price's avatar Andrew Price Committed by Greg Kroah-Hartman
Browse files

gfs2: Add missing rcu locking for glock lookup 



commit f38e5fb95a1f8feda88531eedc98f69b24748712 upstream.

We must hold the rcu read lock across looking up glocks and trying to
bump their refcount to prevent the glocks from being freed in between.

Signed-off-by: default avatarAndrew Price <anprice@redhat.com>
Signed-off-by: default avatarAndreas Gruenbacher <agruenba@redhat.com>
Signed-off-by: default avatarBob Peterson <rpeterso@redhat.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent c8cdd923

fs/gfs2/glock.c

+5 −0
Original line number Diff line number Diff line
@@ -658,9 +658,11 @@ int gfs2_glock_get(struct gfs2_sbd *sdp, u64 number, 
	struct kmem_cache *cachep;

	int ret, tries = 0;



	rcu_read_lock();

	gl = rhashtable_lookup_fast(&gl_hash_table, &name, ht_parms);

	if (gl && !lockref_get_not_dead(&gl->gl_lockref))

		gl = NULL;

	rcu_read_unlock();



	*glp = gl;

	if (gl)
@@ -728,15 +730,18 @@ int gfs2_glock_get(struct gfs2_sbd *sdp, u64 number, 


	if (ret == -EEXIST) {

		ret = 0;

		rcu_read_lock();

		tmp = rhashtable_lookup_fast(&gl_hash_table, &name, ht_parms);

		if (tmp == NULL || !lockref_get_not_dead(&tmp->gl_lockref)) {

			if (++tries < 100) {

				rcu_read_unlock();

				cond_resched();

				goto again;

			}

			tmp = NULL;

			ret = -ENOMEM;

		}

		rcu_read_unlock();

	} else {

		WARN_ON_ONCE(ret);

	}