From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:46474) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1XKRj5-0003g5-Uv for qemu-devel@nongnu.org; Thu, 21 Aug 2014 08:44:30 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1XKRiz-00058n-Q7 for qemu-devel@nongnu.org; Thu, 21 Aug 2014 08:44:23 -0400 Received: from mx1.redhat.com ([209.132.183.28]:17202) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1XKRiz-00058j-IW for qemu-devel@nongnu.org; Thu, 21 Aug 2014 08:44:17 -0400 Received: from int-mx11.intmail.prod.int.phx2.redhat.com (int-mx11.intmail.prod.int.phx2.redhat.com [10.5.11.24]) by mx1.redhat.com (8.14.4/8.14.4) with ESMTP id s7LCiHjx012847 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK) for ; Thu, 21 Aug 2014 08:44:17 -0400 From: Stefan Hajnoczi Date: Thu, 21 Aug 2014 13:44:07 +0100 Message-Id: <1408625048-21994-2-git-send-email-stefanha@redhat.com> In-Reply-To: <1408625048-21994-1-git-send-email-stefanha@redhat.com> References: <1408625048-21994-1-git-send-email-stefanha@redhat.com> Subject: [Qemu-devel] [PATCH 1/2] raw-posix: fix O_DIRECT short reads List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: Kevin Wolf , Markus Armbruster , Stefan Hajnoczi The following O_DIRECT read from a <512 byte file fails: $ truncate -s 320 test.img $ qemu-io -n -c 'read -P 0 0 512' test.img qemu-io: can't open device test.img: Could not read image for determining its format: Invalid argument Note that qemu-io completes successfully without the -n (O_DIRECT) option. This patch fixes qemu-iotests ./check -nocache -vmdk 059. Suggested-by: Kevin Wolf Reported-by: Markus Armbruster Signed-off-by: Stefan Hajnoczi --- block/raw-posix.c | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/block/raw-posix.c b/block/raw-posix.c index 1194eb0..a48ce91 100644 --- a/block/raw-posix.c +++ b/block/raw-posix.c @@ -747,6 +747,15 @@ static ssize_t handle_aiocb_rw_linear(RawPosixAIOData *aiocb, char *buf) } if (len == -1 && errno == EINTR) { continue; + } else if (len == -1 && errno == EINVAL && + (aiocb->bs->open_flags & BDRV_O_NOCACHE) && + !(aiocb->aio_type & QEMU_AIO_WRITE) && + offset > 0) { + /* O_DIRECT pread() may fail with EINVAL when offset is unaligned + * after a short read. Assume that O_DIRECT short reads only occur + * at EOF. Therefore this is a short read, not an I/O error. + */ + break; } else if (len == -1) { offset = -errno; break; -- 1.9.3