From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:60279) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1WsWaI-0007iO-JW for qemu-devel@nongnu.org; Thu, 05 Jun 2014 08:16:02 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1WsWa4-0004p1-Sm for qemu-devel@nongnu.org; Thu, 05 Jun 2014 08:15:54 -0400 Received: from mx1.redhat.com ([209.132.183.28]:45421) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1WsWa4-0004oQ-I7 for qemu-devel@nongnu.org; Thu, 05 Jun 2014 08:15:40 -0400 Received: from int-mx10.intmail.prod.int.phx2.redhat.com (int-mx10.intmail.prod.int.phx2.redhat.com [10.5.11.23]) by mx1.redhat.com (8.14.4/8.14.4) with ESMTP id s55CFdcJ013980 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK) for ; Thu, 5 Jun 2014 08:15:39 -0400 From: Markus Armbruster Date: Thu, 5 Jun 2014 14:15:35 +0200 Message-Id: <1401970536-18019-3-git-send-email-armbru@redhat.com> In-Reply-To: <1401970536-18019-1-git-send-email-armbru@redhat.com> References: <1401970536-18019-1-git-send-email-armbru@redhat.com> Subject: [Qemu-devel] [PATCH 2/3] virtio-blk: Bypass error action and I/O accounting on invalid r/w List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: kwolf@redhat.com, uobergfe@redhat.com, stefanha@redhat.com When a device model's I/O operation fails, we execute the error action. This lets layers above QEMU implement thin provisioning, or attempt to correct errors before they reach the guest. But when the I/O operation fails because its invalid, reporting the error to the guest is the only sensible action. If the guest's read or write asks for an invalid sector range, fail the request right away, without considering the error action. No change with error action BDRV_ACTION_REPORT. Furthermore, bypass I/O accounting, because we want to track only I/O that actually reaches the block layer. The next commit will extend "invalid sector range" to cover attempts to read/write beyond the end of the medium. Signed-off-by: Markus Armbruster --- hw/block/virtio-blk.c | 14 ++++++++------ 1 file changed, 8 insertions(+), 6 deletions(-) diff --git a/hw/block/virtio-blk.c b/hw/block/virtio-blk.c index f2b4dca..2c68d0d 100644 --- a/hw/block/virtio-blk.c +++ b/hw/block/virtio-blk.c @@ -300,15 +300,16 @@ static void virtio_blk_handle_write(VirtIOBlockReq *req, MultiReqBuffer *mrb) sector = ldq_p(&req->out->sector); - bdrv_acct_start(req->dev->bs, &req->acct, req->qiov.size, BDRV_ACCT_WRITE); - trace_virtio_blk_handle_write(req, sector, req->qiov.size / 512); if (!virtio_blk_sect_range_ok(req->dev, sector, req->qiov.size)) { - virtio_blk_rw_complete(req, -EIO); + virtio_blk_req_complete(req, VIRTIO_BLK_S_IOERR); + g_free(req); return; } + bdrv_acct_start(req->dev->bs, &req->acct, req->qiov.size, BDRV_ACCT_WRITE); + if (mrb->num_writes == 32) { virtio_submit_multiwrite(req->dev->bs, mrb); } @@ -330,14 +331,15 @@ static void virtio_blk_handle_read(VirtIOBlockReq *req) sector = ldq_p(&req->out->sector); - bdrv_acct_start(req->dev->bs, &req->acct, req->qiov.size, BDRV_ACCT_READ); - trace_virtio_blk_handle_read(req, sector, req->qiov.size / 512); if (!virtio_blk_sect_range_ok(req->dev, sector, req->qiov.size)) { - virtio_blk_rw_complete(req, -EIO); + virtio_blk_req_complete(req, VIRTIO_BLK_S_IOERR); + g_free(req); return; } + + bdrv_acct_start(req->dev->bs, &req->acct, req->qiov.size, BDRV_ACCT_READ); bdrv_aio_readv(req->dev->bs, sector, &req->qiov, req->qiov.size / BDRV_SECTOR_SIZE, virtio_blk_rw_complete, req); -- 1.9.3