From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([140.186.70.92]:41899) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1RmrH0-0001cv-82 for qemu-devel@nongnu.org; Mon, 16 Jan 2012 13:27:15 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1RmrGw-0003nl-1X for qemu-devel@nongnu.org; Mon, 16 Jan 2012 13:27:14 -0500 Received: from mx1.redhat.com ([209.132.183.28]:30717) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1RmrGv-0003nW-Pd for qemu-devel@nongnu.org; Mon, 16 Jan 2012 13:27:10 -0500 From: "Daniel P. Berrange" Date: Mon, 16 Jan 2012 18:11:40 +0000 Message-Id: <1326737500-11202-1-git-send-email-berrange@redhat.com> Subject: [Qemu-devel] [PATCH] Remove O_NOATIME flag from 9pfs open() calls in readonly mode List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: "M. Mohan Kumar" From: "Daniel P. Berrange" When 2c74c2cb4bedddbfa67628fbd5f9273b4e0e9903 added support for the 'readonly' flag against 9p filesystems, it also made QEMU add the O_NOATIME flag as a side-effect. The O_NOATIME flag, however, may only be set by the file owner, or a user with CAP_FOWNER capability. QEMU cannot assume that this is the case for filesytems exported to QEMU. eg, run QEMU as non-root, and attempt to pass the host OS filesystem through to the guest OS with readonly enable. The result is that the guest OS cannot open any files at all. If O_NOATIME is really required, it should be optionally enabled via a separate QEMU command line flag. * hw/9pfs/virtio-9p.c: Remove O_NOATIME Signed-off-by: Daniel P. Berrange --- hw/9pfs/virtio-9p.c | 1 - 1 files changed, 0 insertions(+), 1 deletions(-) diff --git a/hw/9pfs/virtio-9p.c b/hw/9pfs/virtio-9p.c index e6ba6ba..f8e2c07 100644 --- a/hw/9pfs/virtio-9p.c +++ b/hw/9pfs/virtio-9p.c @@ -1391,7 +1391,6 @@ static void v9fs_open(void *opaque) err = -EROFS; goto out; } - flags |= O_NOATIME; } err = v9fs_co_open(pdu, fidp, flags); if (err < 0) { -- 1.7.7.5