Re: [Qemu-devel] [PATCH] qemu-io: Verify read data by patterns

[Christoph Hellwig]

On Thu, Apr 09, 2009 at 03:46:16PM +0200, Kevin Wolf wrote:
> This patch adds a -P option to read and readv which allows to compare the read
> data to a given pattern. This can be used to verify data written by write -P.

Very good, I was doing this manually in my WIP testsuite, but having
qemu-io do this is even better.

>  " -q, -- quite mode, do not show I/O statistics\n"
> @@ -207,8 +208,10 @@ read_f(int argc, char **argv)
>       char *buf;
>       int64_t offset;
>       int count, total;
> +     int pattern = 0;
> +     int use_pattern = 0;
>  
> -     while ((c = getopt(argc, argv, "Cpqv")) != EOF) {
> +     while ((c = getopt(argc, argv, "CpP:qv")) != EOF) {
>               switch (c) {
>               case 'C':
>                       Cflag = 1;
> @@ -216,6 +219,10 @@ read_f(int argc, char **argv)
>               case 'p':
>                       pflag = 1;
>                       break;
> +             case 'P':
> +                     use_pattern = 1;

Following the conventions this variable would be called Pflag, but I'm
not dead set on this.  (The conventions come from the original xfs_io
tool)

> +     if (use_pattern) {
> +             void* cmp_buf = malloc(count);
> +             memset(cmp_buf, pattern, count);
> +             if (memcmp(buf, cmp_buf, count)) {
> +                     printf("Pattern verification failed at offset %lld, %d 
> bytes\n",
> +                             (long long) offset, count);
> +             }

Can we keep the line shorter than 80 characters?