Btrfs: check cache->caching_ctl before returning if caching has started

Commit Message

Josef Bacik Sept. 16, 2010, 8:18 p.m. UTC

None

Patch

diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index 8ef6aa6..91a0a41 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -242,6 +242,12 @@  get_caching_control(struct btrfs_block_group_cache *cache)
 		return NULL;
 	}
 
+	/* We're loading it the fast way, so we don't have a caching_ctl. */
+	if (!cache->caching_ctl) {
+		spin_unlock(&cache->lock);
+		return NULL;
+	}
+
 	ctl = cache->caching_ctl;
 	atomic_inc(&ctl->count);
 	spin_unlock(&cache->lock);