root/user/stressfs.c

DEFINITIONS

1. main

   1 // Demonstrate that moving the "acquire" in iderw after the loop that
   2 // appends to the idequeue results in a race.
   3 
   4 // For this to work, you should also add a spin within iderw's
   5 // idequeue traversal loop.  Adding the following demonstrated a panic
   6 // after about 5 runs of stressfs in QEMU on a 2.1GHz CPU:
   7 //    for (i = 0; i < 40000; i++)
   8 //      asm volatile("");
   9 
  10 #include "kernel/types.h"
  11 #include "kernel/stat.h"
  12 #include "user/user.h"
  13 #include "kernel/fs.h"
  14 #include "kernel/fcntl.h"
  15 
  16 int
  17 main(int argc, char *argv[])
  18 {
  19   int fd, i;
  20   char path[] = "stressfs0";
  21   char data[512];
  22 
  23   printf("stressfs starting\n");
  24   memset(data, 'a', sizeof(data));
  25 
  26   for (i = 0; i < 4; i++)
  27     if (fork() > 0)
  28       break;
  29 
  30   printf("write %d\n", i);
  31 
  32   path[8] += i;
  33   fd = open(path, O_CREATE | O_RDWR);
  34   for (i = 0; i < 20; i++) {
  35     // printf(fd, "%d\n", i);
  36     write(fd, data, sizeof(data));
  37   }
  38   close(fd);
  39 
  40   printf("read\n");
  41 
  42   fd = open(path, O_RDONLY);
  43   for (i = 0; i < 20; i++)
  44     read(fd, data, sizeof(data));
  45   close(fd);
  46 
  47   wait(0);
  48 
  49   exit(0);
  50 }