From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:48440) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1WLHxX-0002ps-B9 for qemu-devel@nongnu.org; Wed, 05 Mar 2014 14:58:36 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1WLHxS-0002Ul-4V for qemu-devel@nongnu.org; Wed, 05 Mar 2014 14:58:30 -0500 Received: from mx1.redhat.com ([209.132.183.28]:26946) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1WLHxR-0002UJ-So for qemu-devel@nongnu.org; Wed, 05 Mar 2014 14:58:26 -0500 Message-ID: <531781D4.40800@redhat.com> Date: Wed, 05 Mar 2014 20:58:12 +0100 From: Max Reitz MIME-Version: 1.0 References: <1393860533-2063-1-git-send-email-mreitz@redhat.com> <1393860533-2063-3-git-send-email-mreitz@redhat.com> <20140305160455.GD1709@irqsave.net> In-Reply-To: <20140305160455.GD1709@irqsave.net> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: quoted-printable Subject: Re: [Qemu-devel] [PATCH 02/10] block/json: Add JSON protocol driver List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: =?ISO-8859-1?Q?Beno=EEt_Canet?= Cc: Kevin Wolf , qemu-devel@nongnu.org, Stefan Hajnoczi On 05.03.2014 17:04, Beno=EEt Canet wrote: > The Monday 03 Mar 2014 =E0 16:28:45 (+0100), Max Reitz wrote : >> Add a JSON protocol driver which allows supplying block driver options >> through the filename rather than separately. Other than that, it is a >> pure passthrough driver which identifies itself as a filter. >> >> This patch implements the functions bdrv_parse_filename(), >> bdrv_file_open(), bdrv_close(), bdrv_aio_readv(), bdrv_aio_writev(), >> bdrv_getlength(), bdrv_refresh_limits() and bdrv_get_info(). >> >> Signed-off-by: Max Reitz >> --- >> block/Makefile.objs | 2 +- >> block/json.c | 136 ++++++++++++++++++++++++++++++++++++++++++= ++++++++++ >> 2 files changed, 137 insertions(+), 1 deletion(-) >> create mode 100644 block/json.c >> >> diff --git a/block/Makefile.objs b/block/Makefile.objs >> index fd88c03..d4b70f4 100644 >> --- a/block/Makefile.objs >> +++ b/block/Makefile.objs >> @@ -5,7 +5,7 @@ block-obj-y +=3D qed-check.o >> block-obj-$(CONFIG_VHDX) +=3D vhdx.o vhdx-endian.o vhdx-log.o >> block-obj-$(CONFIG_QUORUM) +=3D quorum.o >> block-obj-y +=3D parallels.o blkdebug.o blkverify.o >> -block-obj-y +=3D snapshot.o qapi.o >> +block-obj-y +=3D snapshot.o qapi.o json.o >> block-obj-$(CONFIG_WIN32) +=3D raw-win32.o win32-aio.o >> block-obj-$(CONFIG_POSIX) +=3D raw-posix.o >> block-obj-$(CONFIG_LINUX_AIO) +=3D linux-aio.o >> diff --git a/block/json.c b/block/json.c >> new file mode 100644 >> index 0000000..6d63cf6 >> --- /dev/null >> +++ b/block/json.c >> @@ -0,0 +1,136 @@ >> +/* >> + * JSON filename wrapper protocol driver >> + * >> + * Copyright (c) 2014 Red Hat Inc. >> + * >> + * This program is free software; you can redistribute it and/or modi= fy >> + * it under the terms of the GNU General Public License as published = by >> + * the Free Software Foundation; either version 2 of the License, or >> + * (at your option) any later version. >> + * >> + * This program is distributed in the hope that it will be useful, >> + * but WITHOUT ANY WARRANTY; without even the implied warranty of >> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the >> + * GNU General Public License for more details. >> + * >> + * You should have received a copy of the GNU General Public License >> + * along with this program. If not, see . >> + */ >> + >> +#include "qemu-common.h" >> +#include "block/block_int.h" >> +#include "qapi/qmp/qdict.h" >> +#include "qapi/qmp/qjson.h" >> + >> +static void json_parse_filename(const char *filename, QDict *options, >> + Error **errp) >> +{ >> + QObject *file_options_obj; >> + QDict *full_options; >> + >> + if (!strstart(filename, "json:", &filename)) { >> + error_setg(errp, "Unknown protocol prefix for JSON block driv= er"); >> + return; >> + } >> + >> + file_options_obj =3D qobject_from_json(filename); >> + if (!file_options_obj) { >> + error_setg(errp, "Could not parse the JSON options"); >> + return; >> + } >> + >> + if (qobject_type(file_options_obj) !=3D QTYPE_QDICT) { >> + qobject_decref(file_options_obj); >> + error_setg(errp, "Invalid JSON object"); >> + return; >> + } >> + >> + full_options =3D qdict_new(); >> + qdict_put_obj(full_options, "x-options", file_options_obj); >> + qdict_flatten(full_options); >> + >> + qdict_join(options, full_options, true); >> + assert(qdict_size(full_options) =3D=3D 0); >> + QDECREF(full_options); >> +} >> + >> +static int json_open(BlockDriverState *bs, QDict *options, int flags, >> + Error **errp) >> +{ >> + int ret; >> + >> + assert(bs->file =3D=3D NULL); >> + ret =3D bdrv_open_image(&bs->file, NULL, options, "x-options", fl= ags, false, >> + errp); > >> + if (ret < 0) { >> + return ret; >> + } >> + >> + return 0; > Why not ? > return ret; > } > > Do you plan to enrich this code path later ? You're right, that'd be shorter. It's just that I'm so in the habit of=20 writing "ret =3D foo(); if (ret < 0) { return ret; / goto fail; }" that I= =20 didn't notice. ;-) >> +} >> + >> +static void json_close(BlockDriverState *bs) >> +{ >> +} >> + >> +static BlockDriverAIOCB *json_aio_readv(BlockDriverState *bs, >> + int64_t sector_num, QEMUIOVec= tor *qiov, >> + int nb_sectors, >> + BlockDriverCompletionFunc *cb= , >> + void *opaque) >> +{ >> + return bdrv_aio_readv(bs->file, sector_num, qiov, nb_sectors, cb,= opaque); >> +} >> + >> +static BlockDriverAIOCB *json_aio_writev(BlockDriverState *bs, >> + int64_t sector_num, QEMUIOVe= ctor *qiov, >> + int nb_sectors, >> + BlockDriverCompletionFunc *c= b, >> + void *opaque) >> +{ >> + return bdrv_aio_writev(bs->file, sector_num, qiov, nb_sectors, cb= , opaque); >> +} >> + >> +static int64_t json_getlength(BlockDriverState *bs) >> +{ >> + return bdrv_getlength(bs->file); >> +} >> + >> +static int json_refresh_limits(BlockDriverState *bs) >> +{ >> + bs->bl =3D bs->file->bl; >> + return 0; >> +} >> + >> +static int json_get_info(BlockDriverState *bs, BlockDriverInfo *bdi) >> +{ >> + return bdrv_get_info(bs->file, bdi); >> +} >> + >> +static BlockDriver bdrv_json =3D { >> + .format_name =3D "json", >> + .protocol_name =3D "json", >> + .instance_size =3D 0, >> + >> + .bdrv_parse_filename =3D json_parse_filename, >> + .bdrv_file_open =3D json_open, >> + .bdrv_close =3D json_close, >> + >> + .bdrv_aio_readv =3D json_aio_readv, >> + .bdrv_aio_writev =3D json_aio_writev, >> + >> + .has_variable_length =3D true, >> + .bdrv_getlength =3D json_getlength, >> + >> + .bdrv_refresh_limits =3D json_refresh_limits, >> + .bdrv_get_info =3D json_get_info, >> + >> + .authorizations =3D { true, true }, > Paolo make rewrite the snapshot authorization code. > In the new version you need > .is_filter =3D true; > .bdrv_recurse_is_first_children =3D your_implementation; > > I don't know when these patchset will be reviewed and merged so maybe t= his > version is correct. I'll just rebase on top of Paolo's series then. Thanks, Max >> +}; >> + >> +static void bdrv_json_init(void) >> +{ >> + bdrv_register(&bdrv_json); >> +} >> + >> +block_init(bdrv_json_init); >> --=20 >> 1.9.0 >> >>