Explain what is the problem with this implementation of the one-writer many-readers problem?

 

// shared and initialized to 0 // shared and initialized to 1; int readcount; Semaphore mutex, wrt; // Writer : // Readers : semWait (mutex); readcount := readcount + 1; semWait (wrt); if readcount == 1 then semWait (wrt); semSignal (mutex); /*reading performed*/ semWait (mutex); /* Writing performed*/ semsignal (wrt); readcount := readcount 1; if readcount semSignal (mutex); o then Up (wrt) ;