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

[Christoph Hellwig <hch@lst.de>]

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?