From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:60183) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1UnFeh-00012b-9R for qemu-devel@nongnu.org; Thu, 13 Jun 2013 18:06:08 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1UnFeg-0004Mw-Do for qemu-devel@nongnu.org; Thu, 13 Jun 2013 18:06:07 -0400 Received: from mail-qe0-f52.google.com ([209.85.128.52]:60417) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1UnFeg-0004Mq-A0 for qemu-devel@nongnu.org; Thu, 13 Jun 2013 18:06:06 -0400 Received: by mail-qe0-f52.google.com with SMTP id i11so6933736qej.11 for ; Thu, 13 Jun 2013 15:06:06 -0700 (PDT) Sender: Paolo Bonzini Message-ID: <51BA424A.2020105@redhat.com> Date: Thu, 13 Jun 2013 18:06:02 -0400 From: Paolo Bonzini MIME-Version: 1.0 References: <1371124063-12971-1-git-send-email-kwolf@redhat.com> <1371124063-12971-6-git-send-email-kwolf@redhat.com> In-Reply-To: <1371124063-12971-6-git-send-email-kwolf@redhat.com> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH 5/5] block: Always enable discard on the protocol level List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Kevin Wolf Cc: qemu-devel@nongnu.org, stefanha@redhat.com Il 13/06/2013 07:47, Kevin Wolf ha scritto: > Turning on discard options in qcow2 doesn't help a lot when the discard > requests that it issues are thrown away by the raw-posix layer. This > patch always enables discard functionality on the protocol level so that > it's the image format's responsibility to send (or not) discard > requests. Requests sent by the guest will be allowed or ignored by the > top level BlockDriverState, which depends on the discard=... option like > before. > > In particular, this means that even without specifying options, the > qcow2 default of discarding deleted snapshots actually takes effect now, > both for qemu and qemu-img. > > Signed-off-by: Kevin Wolf > --- > block.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/block.c b/block.c > index 79ad33d..0a7cf2f 100644 > --- a/block.c > +++ b/block.c > @@ -1045,7 +1045,7 @@ int bdrv_open(BlockDriverState *bs, const char *filename, QDict *options, > extract_subqdict(options, &file_options, "file."); > > ret = bdrv_file_open(&file, filename, file_options, > - bdrv_open_flags(bs, flags)); > + bdrv_open_flags(bs, flags | BDRV_O_UNMAP)); > if (ret < 0) { > goto fail; > } > Can you still disable it with -drive file.discard=ignore? Paolo