gfs2: Add missing rcu locking for glock lookup
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.
Cc: <stable@vger.kernel.org> # 4.3+
Signed-off-by: Andrew Price <anprice@redhat.com>
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Signed-off-by: Bob Peterson <rpeterso@redhat.com>
diff --git a/fs/gfs2/glock.c b/fs/gfs2/glock.c
index 2928f12..d004debe 100644
--- a/fs/gfs2/glock.c
+++ b/fs/gfs2/glock.c
@@ -658,9 +658,11 @@
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 @@
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);
}