From: Olaf Hering <olaf@aepfle.de>
Date: Thu, 20 Feb 2014 17:57:13 +0000 (+0000)
Subject: xen_disk: fix io accounting
X-Git-Tag: v2.0.0-rc0~70^2
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=58da5b1e01a586eb5a52ba3eec342d6828269839;p=thirdparty%2Fqemu.git

xen_disk: fix io accounting

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>
Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
---

diff --git a/hw/block/xen_disk.c b/hw/block/xen_disk.c
index 098f6c62c78..7f0f14ae523 100644
--- a/hw/block/xen_disk.c
+++ b/hw/block/xen_disk.c
@@ -483,7 +483,18 @@ 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;
+        }
+    case BLKIF_OP_READ:
+        bdrv_acct_done(ioreq->blkdev->bs, &ioreq->acct);
+        break;
+    default:
+        break;
+    }
     qemu_bh_schedule(ioreq->blkdev->bh);
 }