im pretty sure scsi reports the last addressable sector, as opposed to the
total number of sectors. will have a diff shortly.
dlg
On 20/12/2010, at 2:15 AM, Marco Peereboom wrote:
> I could swear we had the sizes right but I'll have another look at this.
>
> What raid type did you test this with?
>
> On Sun, Dec 19, 2010 at 02:17:46PM +0100, Andreas Bartelt wrote:
>> 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).
>>
>> 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);
