SIZESB
DIRSIZE(IP) + SIZECG(IP) + INODESIZE + SIZESB
#define TOP_RMDIR_SIZE (SIZESB + (INODESIZE * 2) + SIZEDIR)
#define TOP_SBUPDATE_SIZE (SIZESB)
#define TOP_SBWRITE_SIZE (SIZESB)
#define TOP_MOUNT_SIZE (SIZESB)