Btrfs: delay commits during fsync to allow more writers

Signed-off-by: Chris Mason <chris.mason@oracle.com>
diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index d3cd564..c7f5161 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -301,6 +301,7 @@
 	struct radix_tree_root extent_map_radix;
 	struct radix_tree_root extent_ins_radix;
 	u64 generation;
+	u64 last_trans_committed;
 	struct btrfs_transaction *running_transaction;
 	struct btrfs_super_block *disk_super;
 	struct btrfs_super_block super_copy;