EXT2: various fixes

.enable all compile time warnings and make them errors
.refactor functions with unused parameters
.fix null pointer dereference before checking for null
.proper variable initialization
.use safe string copy functions
.fix massive memory corruption bug in fs_getdents

servers/ext2/write.c

@@ -41,7 +41,7 @@ int op;				/* special actions */
   long excess, block_pos;
   char new_ind = 0, new_dbl = 0, new_triple = 0;
   int single = 0, triple = 0;
-  register block_t old_block, b1, b2, b3;
+  block_t old_block = NO_BLOCK, b1 = NO_BLOCK, b2 = NO_BLOCK, b3 = NO_BLOCK;
   struct buf *bp = NULL,
              *bp_dindir = NULL,
              *bp_tindir = NULL;