From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:60784) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1W6j7p-0007gH-D5 for qemu-devel@nongnu.org; Fri, 24 Jan 2014 10:57:03 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1W6j7j-0005CJ-Ev for qemu-devel@nongnu.org; Fri, 24 Jan 2014 10:56:57 -0500 Received: from mx1.redhat.com ([209.132.183.28]:32648) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1W6j7j-0005Br-7N for qemu-devel@nongnu.org; Fri, 24 Jan 2014 10:56:51 -0500 Received: from int-mx09.intmail.prod.int.phx2.redhat.com (int-mx09.intmail.prod.int.phx2.redhat.com [10.5.11.22]) by mx1.redhat.com (8.14.4/8.14.4) with ESMTP id s0OFunxZ024580 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK) for ; Fri, 24 Jan 2014 10:56:49 -0500 Date: Fri, 24 Jan 2014 10:56:45 -0500 From: Jeff Cody Message-ID: <20140124155645.GA19754@localhost.localdomain> References: <1390568901-25060-1-git-send-email-kwolf@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1390568901-25060-1-git-send-email-kwolf@redhat.com> Subject: Re: [Qemu-devel] [PATCH] block: Fix bdrv_commit return value List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Kevin Wolf Cc: qemu-devel@nongnu.org, stefanha@redhat.com On Fri, Jan 24, 2014 at 02:08:21PM +0100, Kevin Wolf wrote: > bdrv_commit() could return 0 or 1 on success, depending on whether or > now the last sector was allocated in the overlay and whether the overlay > format had a .bdrv_make_empty callback. > > Most callers ignored it, but qemu-img commit would print an error > message while the operation actually succeeded. > > Also clean up the handling of I/O errors to return the real error code > instead of -EIO. > > Signed-off-by: Kevin Wolf > --- > block.c | 15 ++++++++++----- > 1 file changed, 10 insertions(+), 5 deletions(-) > > diff --git a/block.c b/block.c > index 3e0994b..7d22ca9 100644 > --- a/block.c > +++ b/block.c > @@ -2061,13 +2061,13 @@ int bdrv_commit(BlockDriverState *bs) > goto ro_cleanup; > } > if (ret) { > - if (bdrv_read(bs, sector, buf, n) != 0) { > - ret = -EIO; > + ret = bdrv_read(bs, sector, buf, n); > + if (ret < 0) { > goto ro_cleanup; > } > > - if (bdrv_write(bs->backing_hd, sector, buf, n) != 0) { > - ret = -EIO; > + ret = bdrv_write(bs->backing_hd, sector, buf, n); > + if (ret < 0) { > goto ro_cleanup; > } > } > @@ -2075,6 +2075,9 @@ int bdrv_commit(BlockDriverState *bs) > > if (drv->bdrv_make_empty) { > ret = drv->bdrv_make_empty(bs); > + if (ret < 0) { > + goto ro_cleanup; > + } QED has a .bdrv_make_empty implementation, but it is a stub that always returns -ENOTSUP. Prior to this patch, a commit of a QED snapshot would complete OK, but return an error saying "Image is already committed" (Which almost seems like a non-error error). Now, we'll skip ahead to cleanup. I think we should either: 1) filter out -ENOTSUP here, or 2) remove the stub from QED > bdrv_flush(bs); > } > > @@ -2082,9 +2085,11 @@ int bdrv_commit(BlockDriverState *bs) > * Make sure all data we wrote to the backing device is actually > * stable on disk. > */ > - if (bs->backing_hd) > + if (bs->backing_hd) { > bdrv_flush(bs->backing_hd); > + } > > + ret = 0; > ro_cleanup: > g_free(buf); > > -- > 1.8.1.4 >