From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:45361) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1WYGEp-0003PA-20 for qemu-devel@nongnu.org; Thu, 10 Apr 2014 10:46:05 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1WYGEi-0005mv-H9 for qemu-devel@nongnu.org; Thu, 10 Apr 2014 10:45:58 -0400 Received: from mx1.redhat.com ([209.132.183.28]:59714) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1WYGEi-0005mo-5U for qemu-devel@nongnu.org; Thu, 10 Apr 2014 10:45:52 -0400 Received: from int-mx13.intmail.prod.int.phx2.redhat.com (int-mx13.intmail.prod.int.phx2.redhat.com [10.5.11.26]) by mx1.redhat.com (8.14.4/8.14.4) with ESMTP id s3AEjofn028011 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK) for ; Thu, 10 Apr 2014 10:45:51 -0400 Message-ID: <5346AE99.6060104@redhat.com> Date: Thu, 10 Apr 2014 16:45:45 +0200 From: Max Reitz MIME-Version: 1.0 References: <1396961442-24046-1-git-send-email-mreitz@redhat.com> <1396961442-24046-6-git-send-email-mreitz@redhat.com> <20140410090541.GG22890@T430.nay.redhat.com> In-Reply-To: <20140410090541.GG22890@T430.nay.redhat.com> Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: quoted-printable Subject: Re: [Qemu-devel] [PATCH v2 5/6] qemu-img: Specify backing file for commit List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Fam Zheng Cc: Kevin Wolf , qemu-devel@nongnu.org, Stefan Hajnoczi On 10.04.2014 11:05, Fam Zheng wrote: > On Tue, 04/08 14:50, Max Reitz wrote: >> Introduce a new parameter for qemu-img commit which may be used to >> explicitly specify the backing file unto which an image should be >> committed if the backing chain has more than a single layer. >> >> Signed-off-by: Max Reitz >> --- >> qemu-img-cmds.hx | 4 ++-- >> qemu-img.c | 22 +++++++++++++++------- >> qemu-img.texi | 8 +++++++- >> 3 files changed, 24 insertions(+), 10 deletions(-) >> >> diff --git a/qemu-img-cmds.hx b/qemu-img-cmds.hx >> index 8bc55cd..7f62f6d 100644 >> --- a/qemu-img-cmds.hx >> +++ b/qemu-img-cmds.hx >> @@ -22,9 +22,9 @@ STEXI >> ETEXI >> =20 >> DEF("commit", img_commit, >> - "commit [-q] [-f fmt] [-t cache] [-p] filename") >> + "commit [-q] [-f fmt] [-t cache] [-b backing_file] [-p] filename"= ) >> STEXI >> -@item commit [-q] [-f @var{fmt}] [-t @var{cache}] [-p] @var{filename} >> +@item commit [-q] [-f @var{fmt}] [-t @var{cache}] [-b @var{backing_fi= le}] [-p] @var{filename} >> ETEXI >> =20 >> DEF("compare", img_compare, >> diff --git a/qemu-img.c b/qemu-img.c >> index 0a9eff7..9d4bdbc 100644 >> --- a/qemu-img.c >> +++ b/qemu-img.c >> @@ -725,15 +725,16 @@ static void run_block_job(BlockJob *job, Error *= *errp) >> static int img_commit(int argc, char **argv) >> { >> int c, ret, flags; >> - const char *filename, *fmt, *cache; >> + const char *filename, *fmt, *cache, *base; >> BlockDriverState *bs, *base_bs; >> bool progress =3D false, quiet =3D false; >> Error *local_err =3D NULL; >> =20 >> fmt =3D NULL; >> cache =3D BDRV_DEFAULT_CACHE; >> + base =3D NULL; >> for(;;) { >> - c =3D getopt(argc, argv, "f:ht:qp"); >> + c =3D getopt(argc, argv, "f:ht:b:qp"); >> if (c =3D=3D -1) { >> break; >> } >> @@ -748,6 +749,9 @@ static int img_commit(int argc, char **argv) >> case 't': >> cache =3D optarg; >> break; >> + case 'b': >> + base =3D optarg; >> + break; >> case 'p': >> progress =3D true; >> break; >> @@ -782,12 +786,16 @@ static int img_commit(int argc, char **argv) >> qemu_progress_init(progress, 1.f); >> qemu_progress_print(0.f, 100); >> =20 >> - /* This is different from QMP, which by default uses the deepest = file in the >> - * backing chain (i.e., the very base); however, the traditional = behavior of >> - * qemu-img commit is using the immediate backing file. */ >> - base_bs =3D bs->backing_hd; >> + if (base) { >> + base_bs =3D bdrv_find_backing_image(bs, base); >> + } else { >> + /* This is different from QMP, which by default uses the deep= est file in >> + * the backing chain (i.e., the very base); however, the trad= itional >> + * behavior of qemu-img commit is using the immediate backing= file. */ >> + base_bs =3D bs->backing_hd; >> + } >> if (!base_bs) { >> - error_set(&local_err, QERR_BASE_NOT_FOUND, "NULL"); >> + error_set(&local_err, QERR_BASE_NOT_FOUND, base ?: "NULL"); >> goto done; >> } >> =20 >> diff --git a/qemu-img.texi b/qemu-img.texi >> index 1a9c08f..4a9f493 100644 >> --- a/qemu-img.texi >> +++ b/qemu-img.texi >> @@ -140,7 +140,7 @@ this case. @var{backing_file} will never be modifi= ed unless you use the >> The size can also be specified using the @var{size} option with @cod= e{-o}, >> it doesn't need to be specified separately in this case. >> =20 >> -@item commit [-q] [-f @var{fmt}] [-t @var{cache}] [-p] @var{filename} >> +@item commit [-q] [-f @var{fmt}] [-t @var{cache}] [-b @var{backing_fi= le}] [-p] @var{filename} >> =20 >> Commit the changes recorded in @var{filename} in its base image or b= acking file. >> If the backing file is smaller than the snapshot, then the backing f= ile will be >> @@ -149,6 +149,12 @@ the backing file, the backing file will not be tr= uncated. If you want the >> backing file to match the size of the smaller snapshot, you can safe= ly truncate >> it yourself once the commit operation successfully completes. >> =20 >> +If the backing chain of the given image file @var{filename} has more = than one >> +layer, the backing file unto which the changes shall be committed may= be >> +specified as @var{backing_file} (which has to be part of @var{filenam= e}'s >> +backing chain). If @var{filename} is not specified, the immediate bac= king file > s/@var{filename}/@var{backing_file}/ ? Right. > BTW how about just calling it 'base' as in qmp commands, because backin= g_file > has usages in (slightly) different context of create. I just called it =93backing_file=94, as there are currently no qemu-img=20 commands with a =93base=94 parameter; then again, there aren't any qemu-i= mg=20 commands for which a filename of the backing chain may be specified, so=20 you're correct. Max > Other than the two questions, > > Reviewed-by: Fam Zheng > >> +of the top image (which is @var{filename}) will be used. >> + >> @item compare [-f @var{fmt}] [-F @var{fmt}] [-p] [-s] [-q] @var{file= name1} @var{filename2} >> =20 >> Check if two images have the same content. You can compare images wi= th >> --=20 >> 1.9.1 >> >>