logfs: commit reservations under space pressure

Ensures we only return -ENOSPC when there really is no space.

Signed-off-by: Joern Engel <joern@logfs.org>
diff --git a/fs/logfs/logfs.h b/fs/logfs/logfs.h
index 32bf556..26a9458 100644
--- a/fs/logfs/logfs.h
+++ b/fs/logfs/logfs.h
@@ -394,6 +394,7 @@
 	int	 s_lock_count;
 	mempool_t *s_block_pool;		/* struct logfs_block pool */
 	mempool_t *s_shadow_pool;		/* struct logfs_shadow pool */
+	struct list_head s_writeback_list;	/* writeback pages */
 	/*
 	 * Space accounting:
 	 * - s_used_bytes specifies space used to store valid data objects.