* [Qemu-devel] [PATCH v2] xen_disk: fix io accounting
@ 2014-02-07 14:47 Olaf Hering
2014-02-07 14:57 ` Stefano Stabellini
2014-02-07 16:17 ` Kevin Wolf
0 siblings, 2 replies; 4+ messages in thread
From: Olaf Hering @ 2014-02-07 14:47 UTC (permalink / raw)
To: qemu-devel; +Cc: kwolf, Olaf Hering, stefanha, stefano.stabellini
bdrv_acct_done was called unconditional. But in case the ioreq has no
segments there is no matching bdrv_acct_start call. This could lead to
bogus accounting values.
Found by code inspection.
Signed-off-by: Olaf Hering <olaf@aepfle.de>
---
v2:
add comment /* fall through */
hw/block/xen_disk.c | 14 +++++++++++++-
1 file changed, 13 insertions(+), 1 deletion(-)
diff --git a/hw/block/xen_disk.c b/hw/block/xen_disk.c
index 098f6c6..fb4ca4a 100644
--- a/hw/block/xen_disk.c
+++ b/hw/block/xen_disk.c
@@ -483,7 +483,19 @@ 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_WRITE:
+ case BLKIF_OP_FLUSH_DISKCACHE:
+ if (!ioreq->req.nr_segments) {
+ break;
+ }
+ /* fall through */
+ case BLKIF_OP_READ:
+ bdrv_acct_done(ioreq->blkdev->bs, &ioreq->acct);
+ break;
+ default:
+ break;
+ }
qemu_bh_schedule(ioreq->blkdev->bh);
}
^ permalink raw reply related [flat|nested] 4+ messages in thread* Re: [Qemu-devel] [PATCH v2] xen_disk: fix io accounting
2014-02-07 14:47 [Qemu-devel] [PATCH v2] xen_disk: fix io accounting Olaf Hering
@ 2014-02-07 14:57 ` Stefano Stabellini
2014-02-07 15:03 ` Olaf Hering
2014-02-07 16:17 ` Kevin Wolf
1 sibling, 1 reply; 4+ messages in thread
From: Stefano Stabellini @ 2014-02-07 14:57 UTC (permalink / raw)
To: Olaf Hering; +Cc: kwolf, qemu-devel, stefanha, stefano.stabellini
On Fri, 7 Feb 2014, Olaf Hering wrote:
> bdrv_acct_done was called unconditional. But in case the ioreq has no
> segments there is no matching bdrv_acct_start call. This could lead to
> bogus accounting values.
>
> Found by code inspection.
>
> Signed-off-by: Olaf Hering <olaf@aepfle.de>
added to my queue, I'll fix the tab manually
> v2:
> add comment /* fall through */
>
> hw/block/xen_disk.c | 14 +++++++++++++-
> 1 file changed, 13 insertions(+), 1 deletion(-)
>
> diff --git a/hw/block/xen_disk.c b/hw/block/xen_disk.c
> index 098f6c6..fb4ca4a 100644
> --- a/hw/block/xen_disk.c
> +++ b/hw/block/xen_disk.c
> @@ -483,7 +483,19 @@ 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_WRITE:
> + case BLKIF_OP_FLUSH_DISKCACHE:
> + if (!ioreq->req.nr_segments) {
> + break;
> + }
> + /* fall through */
> + case BLKIF_OP_READ:
> + bdrv_acct_done(ioreq->blkdev->bs, &ioreq->acct);
> + break;
> + default:
> + break;
> + }
> qemu_bh_schedule(ioreq->blkdev->bh);
> }
>
>
^ permalink raw reply [flat|nested] 4+ messages in thread* Re: [Qemu-devel] [PATCH v2] xen_disk: fix io accounting
2014-02-07 14:47 [Qemu-devel] [PATCH v2] xen_disk: fix io accounting Olaf Hering
2014-02-07 14:57 ` Stefano Stabellini
@ 2014-02-07 16:17 ` Kevin Wolf
1 sibling, 0 replies; 4+ messages in thread
From: Kevin Wolf @ 2014-02-07 16:17 UTC (permalink / raw)
To: Olaf Hering; +Cc: qemu-devel, stefanha, stefano.stabellini
Am 07.02.2014 um 15:47 hat Olaf Hering geschrieben:
> bdrv_acct_done was called unconditional. But in case the ioreq has no
> segments there is no matching bdrv_acct_start call. This could lead to
> bogus accounting values.
>
> Found by code inspection.
>
> Signed-off-by: Olaf Hering <olaf@aepfle.de>
> ---
> v2:
> add comment /* fall through */
>
> hw/block/xen_disk.c | 14 +++++++++++++-
> 1 file changed, 13 insertions(+), 1 deletion(-)
>
> diff --git a/hw/block/xen_disk.c b/hw/block/xen_disk.c
> index 098f6c6..fb4ca4a 100644
> --- a/hw/block/xen_disk.c
> +++ b/hw/block/xen_disk.c
> @@ -483,7 +483,19 @@ 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_WRITE:
> + case BLKIF_OP_FLUSH_DISKCACHE:
> + if (!ioreq->req.nr_segments) {
> + break;
> + }
> + /* fall through */
> + case BLKIF_OP_READ:
> + bdrv_acct_done(ioreq->blkdev->bs, &ioreq->acct);
> + break;
> + default:
> + break;
> + }
> qemu_bh_schedule(ioreq->blkdev->bh);
> }
I think the default case could actually be abort() because it should
never happen. But either way, you can add:
Acked-by: Kevin Wolf <kwolf@redhat.com>
^ permalink raw reply [flat|nested] 4+ messages in thread
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2014-02-07 14:47 [Qemu-devel] [PATCH v2] xen_disk: fix io accounting Olaf Hering
2014-02-07 14:57 ` Stefano Stabellini
2014-02-07 15:03 ` Olaf Hering
2014-02-07 16:17 ` Kevin Wolf
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