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authorAndrew Price <anprice@redhat.com>2017-02-22 12:05:03 -0500
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2017-03-12 06:41:50 +0100
commit4cf918c804c657c3a8b9cd4bb46171315bdfad62 (patch)
tree714d8363a3aec818f0d459b6a74af1a8d9ab1664 /fs/gfs2
parentc8cdd9234caced510db1a03491af475938f9855a (diff)
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: Andrew Price <anprice@redhat.com> Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com> Signed-off-by: Bob Peterson <rpeterso@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'fs/gfs2')
-rw-r--r--fs/gfs2/glock.c5
1 files changed, 5 insertions, 0 deletions
diff --git a/fs/gfs2/glock.c b/fs/gfs2/glock.c
index 14cbf60167a7..133f322573b5 100644
--- a/fs/gfs2/glock.c
+++ b/fs/gfs2/glock.c
@@ -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 @@ again:
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);
}