qemu-io-sim.c

   1 /*
   2  * Copyright (c) 2010-2011 IBM
   3  *
   4  * Authors:
   5  *         Chunqiang Tang <ctang@us.ibm.com>
   6  *
   7  * This work is licensed under the terms of the GNU GPL, version 2.
   8  * See the COPYING file in the top-level directory.
   9  */
  10
  11 /*=============================================================================
  12  * qemu-io-sim works with qemu-io to perform simulated testing. The 'sim'
  13  * command allows the user to control the order of disk I/O and callback
  14  * activities in order to test rare race conditions. Note that once 'sim
  15  * enable' is done, it can only test aio_read and aio_write. See block/sim.c
  16  * for the simulated block device driver.
  17  *============================================================================*/
  18
  19 #include "block/blksim.h"
  20
  21 void fvd_init_prefetch (BlockDriverState * bs);
  22 static void sim_start_prefetch(BlockDriverState *bs)
  23 {
  24     if (!bs->drv->format_name || !strncmp (bs->drv->format_name, "fvd", 3)) {
  25         printf ("This image does not support prefetching.\n");
  26         return;
  27     }
  28     fvd_init_prefetch (bs);
  29     printf ("Prefetching started\n");
  30 }
  31
  32 static void sim_help (void)
  33 {
  34     printf ("\n"
  35             " sim enable\t\tenable simulation\n"
  36             " sim list\t\tlist all simulation tasks\n"
  37             " sim <#task> [#ret]\trun a simulation task, optionally uing #ret as the return value of a read/write operation\n"
  38             " sim all [#ret]\t\trun all tasks, optionally using #ret as the return value of read/write tasks\n"
  39             " sim prefetch\t\tstart prefetching\n");
  40 }
  41
  42 static int sim_f(BlockDriverState *bs, int argc, char **argv)
  43 {
  44     int ret = 0;
  45
  46     if (argc == 3) {
  47         ret = atoi (argv[2]);
  48     }
  49     else if (argc != 2) {
  50         sim_help ();
  51         return 0;
  52     }
  53
  54     if (strcmp (argv[1], "enable") == 0) {
  55         if (bs) {
  56             printf ("Please close the image first. \"sim enable\" must be done before the\n"
  57                     "image is opened so that the image is opened with simulation support.\n");
  58         }
  59         else {
  60             enable_block_sim(1/*print*/, 0 /*no random time*/);
  61             printf ("Block device simulation is enabled.\n");
  62         }
  63         return 0;
  64     }
  65
  66     if (!bs) {
  67         fprintf(stderr, "no file open, try 'help open'\n");
  68         return 0;
  69     }
  70
  71     if (!bdrv_find_format("blksim")) {
  72         printf ("\"sim enable\" must be done before invoking any other sim commands.\n");
  73         return 0;
  74     }
  75
  76     if (strcmp (argv[1], "list") == 0) {
  77         sim_list_tasks ();
  78     }
  79     else if (strcmp (argv[1], "prefetch") == 0) {
  80         sim_start_prefetch(bs);
  81     }
  82     else if (strcmp (argv[1], "all") == 0) {
  83         sim_set_disk_io_return_code (ret);
  84         int n = sim_all_tasks ();
  85         sim_set_disk_io_return_code (0);
  86         printf ("Executed %d tasks.\n", n);
  87     }
  88     else {
  89         sim_set_disk_io_return_code (ret);
  90         sim_task_by_uuid (atoll (argv[1]));
  91         sim_set_disk_io_return_code (0);
  92     }
  93
  94     return 0;
  95 }
  96
  97 static const cmdinfo_t sim_cmd = {
  98     .name = "sim",
  99     .altname = "s",
 100     .cfunc = sim_f,
 101     .argmin = 1,
 102     .argmax = 2,
 103     .args = "",
 104     .oneline = "use simulation to control the order of disk I/Os and callbacks",
 105     .flags = CMD_NOFILE_OK,
 106     .help = sim_help,
 107 };