FS-Cache: Make sure FSCACHE_COOKIE_LOOKING_UP cleared on lookup failure

We must make sure that FSCACHE_COOKIE_LOOKING_UP is cleared on lookup failure
(if an object reaches the LC_DYING state), and we should clear it before
clearing FSCACHE_COOKIE_CREATING.

If this doesn't happen then fscache_wait_for_deferred_lookup() may hold
allocation and retrieval operations indefinitely until they're interrupted by
signals - which in turn pins the dying object until they go away.

Signed-off-by: David Howells <dhowells@redhat.com>
This commit is contained in:
David Howells 2009-11-19 18:11:41 +00:00
parent 2175bb06dc
commit d461d26dde

View file

@ -105,6 +105,7 @@ static inline void fscache_done_parent_op(struct fscache_object *object)
static void fscache_object_state_machine(struct fscache_object *object)
{
enum fscache_object_state new_state;
struct fscache_cookie *cookie;
ASSERT(object != NULL);
@ -158,11 +159,17 @@ static void fscache_object_state_machine(struct fscache_object *object)
spin_lock(&object->lock);
object->state = FSCACHE_OBJECT_DYING;
if (object->cookie &&
test_and_clear_bit(FSCACHE_COOKIE_CREATING,
&object->cookie->flags))
wake_up_bit(&object->cookie->flags,
FSCACHE_COOKIE_CREATING);
cookie = object->cookie;
if (cookie) {
if (test_and_clear_bit(FSCACHE_COOKIE_LOOKING_UP,
&cookie->flags))
wake_up_bit(&cookie->flags,
FSCACHE_COOKIE_LOOKING_UP);
if (test_and_clear_bit(FSCACHE_COOKIE_CREATING,
&cookie->flags))
wake_up_bit(&cookie->flags,
FSCACHE_COOKIE_CREATING);
}
spin_unlock(&object->lock);
fscache_done_parent_op(object);