Index: uspace/srv/fs/fat/fat_ops.c
===================================================================
--- uspace/srv/fs/fat/fat_ops.c	(revision 44ecf894e75e499c21daf2e1b5fbc588301e35e5)
+++ uspace/srv/fs/fat/fat_ops.c	(revision 52ff62d3f50509727dcd19954d32d6783a39d956)
@@ -91,4 +91,5 @@
 static bool fat_is_file(fs_node_t *node);
 static service_id_t fat_service_get(fs_node_t *node);
+static long fat_size_block(service_id_t);
 
 /*
@@ -843,4 +844,12 @@
 }
 
+long fat_size_block(service_id_t service_id)
+{
+	fat_bs_t *bs;
+	bs = block_bb_get(service_id);
+
+	return BPC(bs);
+}
+
 /** libfs operations */
 libfs_ops_t fat_libfs_ops = {
@@ -860,5 +869,6 @@
 	.is_directory = fat_is_directory,
 	.is_file = fat_is_file,
-	.service_get = fat_service_get
+	.service_get = fat_service_get,
+	.size_block = fat_size_block
 };