Re: LVM and XFS cannot set blocksize on block device

Rene Salmon
2006-09-27T13:17:53Z

Hi,

Thanks for the replies. The block size of my LV is indeed 4096

helix-priv:~ # blockdev --getbsz /dev/vg_u00/lv_u00
4096

I can mount and use the xfs file system no problems. I have even tested
extending the LV and doing an xfs_grow and that seemed to work no
problems. So I take it I can safely ignore the warning.

Should I report this as a bug? If so Can someone point me to the
bugzilla page or something of the sorts?

Thanks
Rene

Shailendra Tripathi wrote:
>>> Thanks for the reply. The "-s size=4096" helped I was able to create
>>> the file system, then mount it and use it. I did however get a
>>> warning still about "cannot set blocksize on block device".
>
>>
>> I don't know much about the LVM code, my guess is that
>> ioctl(... ,BLKBSZSET, ...) is failing, strace would confirm this.
>
>
> libxfs_device_open () seems to be working with the pre-conceived notion
> of assuming block devices of only 512 bytes in size.
>
> if (!readonly && setblksize && (statb.st_mode & S_IFMT) == S_IFBLK)
> platform_set_blocksize(fd, path, statb.st_rdev, 512);
>
> This eventually calls to set the blk sz to 512. Since, your volume does
> not support less than 4k, it returns EINVAL. I think, libxfs_init should
> be modified to take pass on the -s size option to this call so that it
> does not happen.
> However, I don't see any problem despite this failure. Everything
> else should work fine.
>
>
>
>
>>> Everything seems to be working but I am a bit worried about the
>>> warning message. Following is the message. Any ideas if it is safe
>>> to ignore this or any way to get rid of it?
>>
>>
>> What does:
>>
>> blockdev --getbsz /dev/vg_u00/lv_u00
>>
>> say?
>>
>>
>> If mkfs.xfs is trying to set a blocksize that already matches the
>> underlying device, it woudn't be hard to silence the warning by doing
>> a check before unconditionally setting it, though I don't know that
>> it's worth it.
>>
>>

--
-
--
Rene Salmon
Tulane University
Center for Computational Science
http://www.ccs.tulane.edu
rsalmon@tulane.edu
Tel 504-862-8393
Tel 504-988-8552
Fax 504-862-8392