Re: xfs_repair of critical volume

Dave Chinner
2010-11-17T07:45:40Z

On Tue, Nov 16, 2010 at 11:29:41PM -0800, Eli Morris wrote:
> Hi Dave,
>
> Thanks a lot for your help. I looked at the man page and elsewhere for this info and can't find what this means:
>
>
> extent: [startoffset..endoffset]: startblock..endblock
>
>
> I understand what an offset would be, but what the heck is a startoffset and an endoffset?

startoffset: file offset of the start of the extent
endoffset: file offset of the end of the extent

> Is the formula for the location of the file:
>
> startoffset + startblock through endoffset + endblock, where the blocks and the offsets are in 512 bytes?

no.

> So this file:
>
> 0: [0..1053271]: 5200578944..5201632215
>
> would be contained from:
>
> beginning: (0 + 5200578944) * 512 bytes
> ending: (1053271 + 5201632215) * 512 bytes

No, it translates like this:

Logical Physical
File Offset (bytes) block on disk
------------------- -------------
0 (0..511) 5200578944
1 (512..1023) 5200578945
2 (1024..1536) 5200578946
..... .....
1053270 5201632214
1053271 5201632215

Cheers,

Dave.
--
Dave Chinner
david@fromorbit.com