From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mailman by lists.gnu.org with tmda-scanned (Exim 4.43) id 1JfQPS-0002pM-5F for qemu-devel@nongnu.org; Fri, 28 Mar 2008 22:03:06 -0400 Received: from exim by lists.gnu.org with spam-scanned (Exim 4.43) id 1JfQPQ-0002mH-0s for qemu-devel@nongnu.org; Fri, 28 Mar 2008 22:03:04 -0400 Received: from [199.232.76.173] (helo=monty-python.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1JfQPP-0002m8-VA for qemu-devel@nongnu.org; Fri, 28 Mar 2008 22:03:03 -0400 Received: from mail.codesourcery.com ([65.74.133.4]) by monty-python.gnu.org with esmtps (TLS-1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.60) (envelope-from ) id 1JfQPP-0005UT-BR for qemu-devel@nongnu.org; Fri, 28 Mar 2008 22:03:03 -0400 From: Paul Brook Subject: Re: [kvm-devel] [Qemu-devel] [PATCH] QEMU: fsync AIO writes on flush request Date: Sat, 29 Mar 2008 02:02:53 +0000 References: <20080328150517.GA18077@dmt> <20080328181311.GA19547@dmt> <20080329011751.GB30219@shareable.org> In-Reply-To: <20080329011751.GB30219@shareable.org> MIME-Version: 1.0 Content-Type: text/plain; charset="ansi_x3.4-1968" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200803290202.54431.paul@codesourcery.com> Reply-To: qemu-devel@nongnu.org List-Id: qemu-devel.nongnu.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: kvm-devel > That'll depend on what kind of device is emulated. Does the SCSI > emulation handle multiple in-flight commands with any guarantee on > order? SCSI definitely allows (and we emulate) multiple in flight commands. I can't find any requirement that writes must complete before a subsequent SYNCHRONISE_CACHE. However I don't claim to know the spec that well, and it's probably not a bad idea have them complete anyway. Preferably this would be a completely asynchronous operation. i.e. the sync command returns immediately, but only completes when all preceding writes have completed and been flushed to disk. Paul