On Sun, Dec 19, 2010 at 02:17:46PM +0100, Andreas Bartelt wrote:
quoted text > Hello,
>
> I've noticed that the size of softraid(4) disks is one sector too large.
>
> In the following description, the native disk is sd4c (which is of type
> RAID), and the corresponding virtual softraid(4) disk will be sd5. I
> will assume that sd5 is of discipline CRYPTO, but the problem should be
> the same for all disciplines.
>
> The size for sd5 gets eventually stored in struct sr_metadata as
> sd_meta->ssdi.ssd_size in function sr_crypto_create
> (dev/softraid_crypto.c). Its value gets initially calculated in function
> sr_meta_native_probe (dev/softraid.c):
> size = DL_GETPSIZE(&label.d_partitions[part]) - SR_DATA_OFFSET;
> where SR_DATA_OFFSET = 528
>
> If the size (as shown via disklabel(8)) of the underlying disk sd4c is
> 'n', the variable 'size' will be calculated as 'n - 528'. However,
> according to disklabel(8), the resulting softraid(4) disk sd5c will be
> of size 'n - 528 + 1'. I think this is because function scsi_size in
> scsi/scsi_base.c returns 'max_addr + 1' where max_addr corresponds to
> sd_meta->ssdi.ssd_size.
>
> For example, newfs(8) on /dev/rsd5c tries to write to the last sector of
> sd5 (first wtfs call in mkfs.c) which is one sector beyond the native
> disk size of sd4. This gives an error if label sd4c was used as the
> native device. It results in a kernel panic in case another label of sd4
> was used as the underlying native device (i.e., sd4a).
You should NEVER use 'c' partition. Amoung other things, it is
always set by the kernel to encompass the whole disk, everytime the
disklabel is read. If you restore to a different sized disk interesting
things might happen. I thought we also always set it to UNUSED, but
if not I will revisit that.
.... Ken
quoted text >
> The attached diff fixes the problem for all newly created softraid volumes.
>
> TODO: fixing the problem for existing softraid(4) volumes would require
> to update sd_meta->ssdi.ssd_size to the correct size (and probably some
> other metadata for consistency).
>
> Best regards
> Andreas
> Index: softraid.c
> ===================================================================
> RCS file: /usr/cvsync/cvs/src/sys/dev/softraid.c,v
> retrieving revision 1.216
> diff -u -r1.216 softraid.c
> --- softraid.c 6 Nov 2010 23:01:56 -0000 1.216
> +++ softraid.c 19 Dec 2010 13:01:14 -0000
> @@ -1386,7 +1386,7 @@
> goto unwind;
> }
>
> - size = DL_GETPSIZE(&label.d_partitions[part]) - SR_DATA_OFFSET;
> + size = DL_GETPSIZE(&label.d_partitions[part]) - SR_DATA_OFFSET - 1;
> if (size <= 0) {
> DNPRINTF(SR_D_META, "%s: %s partition too small\n", DEVNAME(sc),
> devname);
