From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:51401) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1aJPTX-0006n9-3Z for qemu-devel@nongnu.org; Wed, 13 Jan 2016 12:44:51 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1aJPTW-0003J4-9x for qemu-devel@nongnu.org; Wed, 13 Jan 2016 12:44:51 -0500 Date: Wed, 13 Jan 2016 18:44:41 +0100 From: Kevin Wolf Message-ID: <20160113174441.GC4356@noname.redhat.com> References: <1452624982-19332-1-git-send-email-berrange@redhat.com> <1452624982-19332-8-git-send-email-berrange@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1452624982-19332-8-git-send-email-berrange@redhat.com> Subject: Re: [Qemu-devel] [Qemu-block] [PATCH v1 07/15] block: add flag to indicate that no I/O will be performed List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: "Daniel P. Berrange" Cc: qemu-devel@nongnu.org, qemu-block@nongnu.org Am 12.01.2016 um 19:56 hat Daniel P. Berrange geschrieben: > When opening an image it is useful to know whether the caller > intends to perform I/O on the image or not. In the case of > encrypted images this will allow the block driver to avoid > having to prompt for decryption keys when we merely want to > query header metadata about the image. eg qemu-img info > > Signed-off-by: Daniel P. Berrange Would it be worth adding assertions to the block layer I/O functions (most importantly, bdrv_aligned_preadv/pwritev) that this flag isn't set? Kevin