[dm-devel] [RFC, PATCH] dm-log.c: Work with devices with hard-sector-size > 512 bytes

Stefan Bader Stefan.Bader at de.ibm.com
Tue Mar 28 12:20:40 UTC 2006


> 
> Unfortunately, the on-disk bitset is hardcoded to be at sector 2, which
> is too small for any device with hard-sector-size > 1k. I've changed
> this offset to sector 64 (32k from start of device), which should be a
> safer choice. However, this necessitated a change of the disk-log 
version
> from 2 to 3, meaning the new code would not be compatible with any
> existing disk-logs. At the moment, I haven't added any code to deal with
> this scenario - I wanted to get some opinions on how to best handle 
this.
> 

Would it really hurt to leave the sector offset just at 2? That way the
bitset data starts at different byte offsets but that would be consistent
with the device. A fix byte offset would only be needed if a device could
change its hardsector size without loosing data, wouldn't it?

Regards,
Stefan Bader




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