* john cooper <john.coo...@redhat.com> [2010-03-25 00:45]:
> This series adds the minimal support to qemu and virtio_blk
> to support passing of a virtio_blk serial id string from qemu
> through the guest driver and to the guest userland.
>
> This is derived in part from a patch set posted by Rusty some
> time ago, but has been minimized to remove support for prior
> versions which attempted to provide the same functionality via
> pci config/io space. This version rather uses a virtio request
> as proposed in Rusty's example.
>
> Also removed is the packaging of the serial/id string within
> the glorious bag of bits returned by the ATA_IDENTIFY command.
> Here we transfer only the 20 bytes of serial/id string from
> qemu to the guest userland. In the proposed interface, this
> is made available by an ioctl() into the virtio_blk driver
> however other interfaces (eg: /sys) have also been proposed.
> A code snippet is attached below as an example of ioctl usage.
>
> The resulting code is quite minimal and I believe it addresses
> all concerns raised in prior versions.
>
> -john
>
>
>
> #include <stdio.h>
> #include <strings.h>
> #include <sys/types.h>
> #include <fcntl.h>
> #include <linux/hdreg.h>
>
> #define IOCTL_CMD 'VBID'
>
> main()
> {
> int fd, rv;
> char buf[512];
>
> bzero(buf, sizeof (buf));
> if ((fd = open("/dev/vda", O_RDONLY)) < 0)
> perror("open");
> else if (ioctl(fd, IOCTL_CMD, buf) < 0)
> perror("ioctl");
> else
> printf("[%s]\n", buf);
> }
Would we want to patch up blkid command to use this so distro stacks can
extract the serial and build the typical /dev/disk/by-id/ links ?
--
Ryan Harper
Software Engineer; Linux Technology Center
IBM Corp., Austin, Tx
ry...@us.ibm.com
