Messages in this thread | | | Date | Fri, 31 Aug 2012 11:24:31 -0400 | Subject | Re: [PATCH 2/2] [RESEND] add discard support to nbd | From | Paul Clements <> |
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On Thu, Aug 30, 2012 at 6:03 PM, Andrew Morton <akpm@linux-foundation.org> wrote: > On Wed, 29 Aug 2012 08:41:02 -0400 > paul.clements@steeleye.com wrote: > >> Description: This patch adds discard support to nbd. When the nbd client >> system receives a discard request, this will be passed along to the nbd >> server system, where the nbd-server will respond by performing: >> fallocate(.. FALLOC_FL_PUNCH_HOLE ..) >> >> To punch a hole in the backend storage, which is no longer needed. >> > > What happens if the user is running an older server?
In that case, the older server will not have set NBD_SEND_FLAG_TRIM, so QUEUE_FLAG_DISCARD doesn't get set, so no discards will be sent to the device.
> I is it possible that because the old server didn't set > NBD_FLAG_SEND_TRIM, the user's screen gets filled with WARN_ONs?
No.
> Anyway, please make sure this combination was tested!
It was.
Thanks for the feedback.
I will resend v2 of the patches shortly.
-- Paul
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