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Date: Mon, 23 May 2011 16:11:54 +0200
From: Kevin Wolf <kwolf@redhat.com>
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Subject: Re: [Qemu-devel] [PATCH] block/raw-posix: use a character device if
 a block device is given
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To: Christoph Egger <Christoph.Egger@amd.com>
Cc: "qemu-devel@nongnu.org" <qemu-devel@nongnu.org>

Am 23.05.2011 14:34, schrieb Christoph Egger:
> 
> if given a block device, use the character device instead.
> 
> From: Manuel Bouyer <bouyer@NetBSD.org>
> Signed-off-by: Christoph Egger <Christoph.Egger@amd.com>

A useful commit message would explain why you're doing that.

> 
> diff --git a/block/raw-posix.c b/block/raw-posix.c
> index 6b72470..d05f373 100644
> --- a/block/raw-posix.c
> +++ b/block/raw-posix.c
> @@ -136,11 +143,45 @@ static int64_t raw_getlength(BlockDriverState *bs);
>   static int cdrom_reopen(BlockDriverState *bs);
>   #endif
> 
> +#if defined(__NetBSD__)
> +static const char *raw_get_rawdevice(const char *filename)
> +{
> +    static char namebuf[PATH_MAX];
> +    const char *dp = strrchr(filename, '/');
> +
> +    if (dp == NULL) {
> +        snprintf(namebuf, PATH_MAX, "r%s", filename);
> +    } else {
> +        snprintf(namebuf, PATH_MAX, "%.*s/r%s",
> +            (int)(dp - filename), filename, dp + 1);
> +    }
> +    fprintf(stderr, "%s is a block device", filename);
> +    filename = namebuf;
> +    fprintf(stderr, ", using %s\n", filename);

Not sure if fprintf is a good idea here, but ok.

> +
> +    return filename;
> +}
> +#else
> +static const char *raw_get_rawdevice(const char *filename)
> +{
> +    return filename;
> +}
> +#endif
> +
>   static int raw_open_common(BlockDriverState *bs, const char *filename,
>                              int bdrv_flags, int open_flags)
>   {
>       BDRVRawState *s = bs->opaque;
>       int fd, ret;
> +    struct stat sb;
> +
> +    if (lstat(filename, &sb) < 0) {
> +        fprintf(stderr, "%s: stat failed: %s\n", filename, 
> strerror(errno));

The patch is corrupted by this line wrap.

Please remove the fprintf, the callers are responsible for sending an
error message to the right destination.

> +        return -errno;
> +    }
> +
> +    if (S_ISBLK(sb.st_mode))
> +        filename = raw_get_rawdevice(filename);

The qemu coding style requires braces.

Also, I agree with Christoph that the lstat/S_ISBLK should be moved into
the NetBSD specific code.

Kevin