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Re: [Qemu-devel] [PATCH] xen_disk: add discard support
From: |
Olaf Hering |
Subject: |
Re: [Qemu-devel] [PATCH] xen_disk: add discard support |
Date: |
Tue, 4 Feb 2014 17:58:19 +0100 |
User-agent: |
Mutt/1.5.22.rev6346 (2013-10-29) |
On Tue, Feb 04, Olaf Hering wrote:
> On Tue, Feb 04, Kevin Wolf wrote:
>
> > Now you call bdrv_acct_done() in the callback without having a matching
> > bdrv_acct_start(). You need to make it conditional in the callback.
> Stefano,
> Is ioreq_runio_qemu_aio symetric in this regard anyway? In case of
> BLKIF_OP_WRITE|BLKIF_OP_FLUSH_DISKCACHE and no ioreq->req.nr_segments
> then qemu_aio_complete is called anyway. Will qemu_aio_complete get down
> to the bdrv_acct_done call at all in this case?
What I have in mind is something like the (not compile tested) change below.
Olaf
diff --git a/hw/block/xen_disk.c b/hw/block/xen_disk.c
index e74efc7..99d36b8 100644
--- a/hw/block/xen_disk.c
+++ b/hw/block/xen_disk.c
@@ -486,7 +486,16 @@ static void qemu_aio_complete(void *opaque, int ret)
ioreq->status = ioreq->aio_errors ? BLKIF_RSP_ERROR : BLKIF_RSP_OKAY;
ioreq_unmap(ioreq);
ioreq_finish(ioreq);
- bdrv_acct_done(ioreq->blkdev->bs, &ioreq->acct);
+ switch (ioreq->req.operation) {
+ case BLKIF_OP_DISCARD:
+ break;
+ case BLKIF_OP_WRITE:
+ case BLKIF_OP_FLUSH_DISKCACHE:
+ if (!ioreq->req.nr_segments) {
+ break;
+ }
+ bdrv_acct_done(ioreq->blkdev->bs, &ioreq->acct);
+ }
qemu_bh_schedule(ioreq->blkdev->bh);
}