[stgt] [PATCH V2] Make virtual tapes more closely emulate physical ones

[FUJITA Tomonori]

Mark, any comment on this?

On Thu, 17 Jan 2013 16:21:36 -0500
Jay Fenlason <fenlason at redhat.com> wrote:

> On Thu, Jan 10, 2013 at 11:36:44AM -0500, Jay Fenlason wrote:
>> On my physical drive (a Sony AIT-2 drive, if it matters) when
>> userspace reads a file mark, it gets an EOF, and the tape is advanced
>> past the file mark so that a subsequent read will return data from the
>> next file on the tape.  With a virtual drive, the file mark is
>> sticky--reads continue to return EOF until the tape is manually
>> advanced with a FSF ioctl.  I wrote this quick patch to make the
>> virtual tape behave like my physical one.
> 
> V2: Replace FIXME with correct error flow.  If the attempt to read the
> next block fails, return ASC_MEDIUM_FORMAT_CORRUPT
> 
> Signed-off-by: Jay Fenlason <fenlason at redhat.com>
> 
> 
> --- tgt-1.0.32/usr/bs_ssc.c.filemark	2012-09-30 18:39:21.000000000 -0400
> +++ tgt-1.0.32/usr/bs_ssc.c	2013-01-17 14:39:54.000000000 -0500
> @@ -325,6 +325,9 @@ static int resp_var_read(struct scsi_cmd
>  		if (h->blk_type == BLK_EOD)
>  			sense_data_build(cmd, 0x40 | BLANK_CHECK,
>  					 NO_ADDITIONAL_SENSE);
> +		else if (h->blk_type == BLK_FILEMARK)
> +			ssc_sense_data_build(cmd, NO_SENSE | SENSE_FILEMARK,
> +					     ASC_MARK, info, sizeof(info));
>  		else
>  			ssc_sense_data_build(cmd, NO_SENSE | 0x20,
>  					     NO_ADDITIONAL_SENSE,
> @@ -339,8 +342,11 @@ static int resp_var_read(struct scsi_cmd
>  
>  		result = SAM_STAT_CHECK_CONDITION;
>  
> -		if (!length)
> +		if (!length) {
> +			if (h->blk_type == BLK_FILEMARK)
> +				goto skip_and_out;
>  			goto out;
> +		}
>  	}
>  
>  	ret = pread64(cmd->dev->fd, buf, length, h->curr + SSC_BLK_HDR_SIZE);
> @@ -351,6 +357,7 @@ static int resp_var_read(struct scsi_cmd
>  	}
>  	*transferred = length;
>  
> +skip_and_out:
>  	ret = skip_next_header(cmd->dev);
>  	if (ret) {
>  		sense_data_build(cmd, MEDIUM_ERROR, ASC_MEDIUM_FORMAT_CORRUPT);
> --
> To unsubscribe from this list: send the line "unsubscribe stgt" in
> the body of a message to majordomo at vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html
--
To unsubscribe from this list: send the line "unsubscribe stgt" in
the body of a message to majordomo at vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html