From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:39363) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1WhnE9-0004ZC-9S for qemu-devel@nongnu.org; Tue, 06 May 2014 17:48:47 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1WhnE3-0000ss-4q for qemu-devel@nongnu.org; Tue, 06 May 2014 17:48:41 -0400 Received: from mx1.redhat.com ([209.132.183.28]:24926) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1WhnE2-0000sf-SS for qemu-devel@nongnu.org; Tue, 06 May 2014 17:48:35 -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 s46LmYUW000835 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK) for ; Tue, 6 May 2014 17:48:34 -0400 Message-ID: <536958AE.1020002@redhat.com> Date: Tue, 06 May 2014 23:48:30 +0200 From: Max Reitz MIME-Version: 1.0 References: <1399402854-24559-1-git-send-email-mreitz@redhat.com> <536951A9.1070200@redhat.com> <53695863.9080009@redhat.com> In-Reply-To: <53695863.9080009@redhat.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH v2] block/raw-posix: Try both FIEMAP and SEEK_HOLE List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Eric Blake , qemu-devel@nongnu.org Cc: Kevin Wolf , Stefan Hajnoczi On 06.05.2014 23:47, Eric Blake wrote: > On 05/06/2014 03:18 PM, Eric Blake wrote: > >> ...if you are on a file system where SEEK_HOLE triggers the kernel >> fallback of "entire file is allocated", but where FIEMAP is wired up for >> that file system, would it make sense to have try_seek_hole return -1 in >> situations where lseek(s->fd, 0, SEEK_HOLE) returns the end of the file? >> Even more, should skip_seek_hole be a tri-state? > On the other hand, such systems are getting vanishingly rare as people > upgrade to newer kernels. Do we care about catering to them, or is it > fair game to just tell people to upgrade if they want performance? How about I'll send v3 and you decide? ;-)