From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from [140.186.70.92] (port=57179 helo=eggs.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1Pl2bZ-00034B-Q2 for qemu-devel@nongnu.org; Thu, 03 Feb 2011 12:04:27 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1Pl2bX-0004Nq-W5 for qemu-devel@nongnu.org; Thu, 03 Feb 2011 12:04:25 -0500 Received: from mx1.redhat.com ([209.132.183.28]:11673) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Pl2bX-0004NX-P8 for qemu-devel@nongnu.org; Thu, 03 Feb 2011 12:04:23 -0500 Message-ID: <4D4AE077.60700@redhat.com> Date: Thu, 03 Feb 2011 18:05:59 +0100 From: Kevin Wolf MIME-Version: 1.0 References: <1296752034-28539-1-git-send-email-ctang@us.ibm.com> In-Reply-To: <1296752034-28539-1-git-send-email-ctang@us.ibm.com> Content-Type: text/plain; charset=ISO-8859-15 Content-Transfer-Encoding: 7bit Subject: [Qemu-devel] Re: [PATCH] QCOW2: fix bug - report read success on failure List-Id: qemu-devel.nongnu.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Chunqiang Tang Cc: Stefan Hajnoczi , qemu-devel@nongnu.org Am 03.02.2011 17:53, schrieb Chunqiang Tang: > This patch fixes bugs in QCOW2's error handling paths of read operations. > When an I/O operation fails, the QCOW2 driver mistakenly reports it as success > to the uper layer. > > This bug was found by Fast Virtual Disk (FVD)'s fully automated testing tool, > when it injected failures. Specifically, the following test triggered the bug. > > /bin/rm -rf /var/ramdisk/truth.raw /var/ramdisk/test.qcow2 /var/ramdisk/zero-500M.raw > dd if=/dev/zero of=/var/ramdisk/truth.raw count=0 bs=1 seek=1112250368 > dd if=/dev/zero of=/var/ramdisk/zero-500M.raw count=0 bs=1 seek=575525376 > ./qemu-img create -f qcow2 -ocluster_size=65536,backing_fmt=blksim -b /var/ramdisk/zero-500M.raw /var/ramdisk/test.qcow2 1112250368 > ./qemu-io --auto --seed=184915369 --truth=/var/ramdisk/truth.raw --format=qcow2 --test=blksim:/var/ramdisk/test.qcow2 --verify_write=true --compare_before=false --compare_after=true --round=100000 --parallel=100 --io_size=1048576 --fail_prob=0.1 --cancel_prob=0 --instant_qemubh=true > > Signed-off-by: Chunqiang Tang > --- > block/qcow2.c | 8 ++++++-- > 1 files changed, 6 insertions(+), 2 deletions(-) > > diff --git a/block/qcow2.c b/block/qcow2.c > index 8c906d1..6f6d56f 100644 > --- a/block/qcow2.c > +++ b/block/qcow2.c > @@ -479,8 +479,10 @@ static void qcow2_aio_read_cb(void *opaque, int ret) > BLKDBG_EVENT(bs->file, BLKDBG_READ_BACKING_AIO); > acb->hd_aiocb = bdrv_aio_readv(bs->backing_hd, acb->sector_num, > &acb->hd_qiov, n1, qcow2_aio_read_cb, acb); > - if (acb->hd_aiocb == NULL) > + if (acb->hd_aiocb == NULL) { > + ret = -EIO; > goto done; > + } > } else { > ret = qcow2_schedule_bh(qcow2_aio_read_bh, acb); > if (ret < 0) Oops, thanks for catching this. I thought this was fixed long ago, but apparently it wasn't. > @@ -495,8 +497,10 @@ static void qcow2_aio_read_cb(void *opaque, int ret) > } > } else if (acb->cluster_offset & QCOW_OFLAG_COMPRESSED) { > /* add AIO support for compressed blocks ? */ > - if (qcow2_decompress_cluster(bs, acb->cluster_offset) < 0) > + if (qcow2_decompress_cluster(bs, acb->cluster_offset) < 0) { > + ret = -EIO; > goto done; > + } I think here we should change qcow2_decompessed_cluster() to return the real error code instead of -1, so that we can pass it on instead of turning everything into -EIO. Kevin