[dm-devel] [PATCH] kpartx: recognize DASD on loop devices again

[Benjamin Marzinski]

On Fri, Jun 28, 2019 at 07:29:41PM +0000, Martin Wilck wrote:
> From: Martin Wilck <mwilck at suse.com>
> 
> Since 4d57b868, DASD partition tables are only recognized on
> DASD hardware. This turns out to break certain software that works
> e.g. with DASD partition tables on loop devices. The problem that
> 4d57b868 attempted to fix was that "unlabeled disk" format has
> no signature at all and is detected on any volume, including
> empty ones.
> 
> With this patch, DASD partition table formats other than "unlabeled
> disk" are detected on non-DASD devices again.
> 
> Fixes: 4d57b868 "kpartx: only recognize dasd part table on DASD"

Reviewed-by: Benjamin Marzinski <bmarzins at redhat.com>

> ---
>  kpartx/dasd.c | 7 ++++---
>  1 file changed, 4 insertions(+), 3 deletions(-)
> 
> diff --git a/kpartx/dasd.c b/kpartx/dasd.c
> index 61b609a5..3fcef6ad 100644
> --- a/kpartx/dasd.c
> +++ b/kpartx/dasd.c
> @@ -133,9 +133,6 @@ read_dasd_pt(int fd, struct slice all, struct slice *sp, int ns)
>  			/* Couldn't open the device */
>  			return -1;
>  		}
> -	} else if ((unsigned int)major(sbuf.st_rdev) != 94) {
> -			/* Not a DASD */
> -			return -1;
>  	} else {
>  		fd_dasd = dup(fd);
>  	}
> @@ -277,6 +274,10 @@ read_dasd_pt(int fd, struct slice all, struct slice *sp, int ns)
>  			size = disksize;
>  			if (fmt_size < size)
>  				size = fmt_size;
> +		} else if ((unsigned int)major(sbuf.st_rdev) != 94) {
> +			/* Not a DASD */
> +			retval = -1;
> +			goto out;
>  		} else
>  			size = disksize;
>  
> -- 
> 2.21.0
>