Re: block ioctl to read/write last sector

From: Michael E Brown (
Date: Wed Feb 14 2001 - 00:47:50 EST

On Wed, 14 Feb 2001, Manfred Spraul wrote:

> I have one additional user space only idea:
> have you tried raw-io? bind a raw device to the partition, IIRC raw-io
> is always in 512 byte units.

That has been tried. No, it does not work. :-) Using Scsi-Generic is the
only way so far found, but of course, it only works on SCSI drives.

> Probably an ioctl is the better idea, but I'd use absolute sector
> numbers (not relative to the end), and obviously 64-bit sector numbers -
> 2 TB isn't that far away.

I was deliberately trying to limit the scope to avoid misuse. This is to
work around a flaw in the current API, not to create a new API. Limiting
access to only those blocks that would normally be inaccessible through
the normal API seemed like the best bet to me.

Michael Brown

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