Btrfs: update comments in cache_save_setup
We also don't bother to flush free space cache while with free space
tree.
Cc: David Sterba <dsterba@suse.cz>
Signed-off-by: Liu Bo <bo.li.liu@oracle.com>
Signed-off-by: David Sterba <dsterba@suse.com>
diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index 5a7ddcf..1b9ede1 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -3443,7 +3443,8 @@ static int cache_save_setup(struct btrfs_block_group_cache *block_group,
/*
* don't bother trying to write stuff out _if_
* a) we're not cached,
- * b) we're with nospace_cache mount option.
+ * b) we're with nospace_cache mount option,
+ * c) we're with v2 space_cache (FREE_SPACE_TREE).
*/
dcs = BTRFS_DC_WRITTEN;
spin_unlock(&block_group->lock);