[dm-devel] [RFC] New interface for dm-io to handle timed requests
Mike Christie
michaelc at cs.wisc.edu
Tue Mar 14 20:15:10 UTC 2006
Stefan Bader wrote:
> Some days ago we proposed an extension to the device mapper that allows
> to specify a timeout after which a given request should return as
> successful, even if some of the target devices did not react by that
> time. As we cannot return a request to the upper layers as long as some
> io is still running and possibly modifying referenced pages, we also
> need a way to handle those requests.
> The ideal solution would be to have an interface in the block layer that
> allows us to cancel any submitted requests. But since such a change will
> take quite a lot discussions and work, we want to emulate such a
> behavior in the dm core for now.
>
The scsi people and some block people have been talking about moving
more error handling functionality into the block layer for a while and
it is slowing moving that way. It could probably be done faster if
people did not concentrate on one subsystem :)
Maybe you should post to lkml and linux-scsi and get some responses from
them before adding it to dm core. If a post already went out to those
list my fault for missing it.
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