FS-Cache: Fix object state machine to have separate work and wait states

[~andy/linux] / fs / fscache / cache.c

diff --git a/fs/fscache/cache.c b/fs/fscache/cache.c
index 129ea537f02396f6fbbd078e06b1d73a3d38bd1c..f7cff367db7f2df8c358b5a723889b4bd8790f54 100644 (file)
--- a/fs/fscache/cache.c
+++ b/fs/fscache/cache.c
@@ -224,8 +224,10 @@ int fscache_add_cache(struct fscache_cache *cache,
        BUG_ON(!ifsdef);
 
        cache->flags = 0;
-       ifsdef->event_mask = ULONG_MAX & ~(1 << FSCACHE_OBJECT_EV_CLEARED);
-       ifsdef->state = FSCACHE_OBJECT_ACTIVE;
+       ifsdef->event_mask =
+               ((1 << NR_FSCACHE_OBJECT_EVENTS) - 1) &
+               ~(1 << FSCACHE_OBJECT_EV_CLEARED);
+       __set_bit(FSCACHE_OBJECT_IS_AVAILABLE, &ifsdef->flags);
 
        if (!tagname)
                tagname = cache->identifier;
@@ -330,25 +332,25 @@ static void fscache_withdraw_all_objects(struct fscache_cache *cache,
 {
        struct fscache_object *object;
 
-       spin_lock(&cache->object_list_lock);
-
        while (!list_empty(&cache->object_list)) {
-               object = list_entry(cache->object_list.next,
-                                   struct fscache_object, cache_link);
-               list_move_tail(&object->cache_link, dying_objects);
+               spin_lock(&cache->object_list_lock);
 
-               _debug("withdraw %p", object->cookie);
+               if (!list_empty(&cache->object_list)) {
+                       object = list_entry(cache->object_list.next,
+                                           struct fscache_object, cache_link);
+                       list_move_tail(&object->cache_link, dying_objects);
 
-               spin_lock(&object->lock);
-               spin_unlock(&cache->object_list_lock);
-               fscache_raise_event(object, FSCACHE_OBJECT_EV_WITHDRAW);
-               spin_unlock(&object->lock);
+                       _debug("withdraw %p", object->cookie);
+
+                       /* This must be done under object_list_lock to prevent
+                        * a race with fscache_drop_object().
+                        */
+                       fscache_raise_event(object, FSCACHE_OBJECT_EV_KILL);
+               }
 
+               spin_unlock(&cache->object_list_lock);
                cond_resched();
-               spin_lock(&cache->object_list_lock);
        }
-
-       spin_unlock(&cache->object_list_lock);
 }
 
 /**