[dm-devel] Opening a dm device reads from cache, not the device.
Heinz Mauelshagen
mauelshagen at redhat.com
Fri Feb 17 17:56:01 UTC 2006
Is this dm-raid45 ?
If so, you'll need to add cluster logic to it (ie. taking locks
out on stripe cache accesses, invalidating stripes etc).
On Wed, Feb 15, 2006 at 05:05:28PM -0700, Allen Jack wrote:
> I have a RAID5 plugin that is also used with clustering. I open the
> raid device (created in device-mapper) using the O_SYNC and O_DIRECT
> flags, but it seems to read the data from a cache somewhere. I put a
> printk in my plugin map function, but it doesn't get hit. If another
> node in the cluster changes the data on the disk, it never gets
> refreshed on this node because of the caching.
>
> Is there any way to turn off the caching so that all read requests come
> to my plugin? And where is the caching taking place?
>
> Thanks,
>
> Allen
>
> Allen Jack
> email - ajack at novell.com
> Novell, Inc., the leading provider of information solutions
> http://www.novell.com
>
> --
> dm-devel mailing list
> dm-devel at redhat.com
> https://www.redhat.com/mailman/listinfo/dm-devel
=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
Heinz Mauelshagen Red Hat GmbH
Consulting Development Engineer Am Sonnenhang 11
Cluster and Storage Development 56242 Marienrachdorf
Germany
Mauelshagen at RedHat.com +49 2626 141200
FAX 924446
=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
More information about the dm-devel
mailing list