The Wednesday 05 Mar 2014 à 20:58:12 (+0100), Max Reitz wrote : > On 05.03.2014 17:04, Benoît Canet wrote: > >The Monday 03 Mar 2014 à 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 <mre...@redhat.com> > >>--- > >> 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 += qed-check.o > >> block-obj-$(CONFIG_VHDX) += vhdx.o vhdx-endian.o vhdx-log.o > >> block-obj-$(CONFIG_QUORUM) += quorum.o > >> block-obj-y += parallels.o blkdebug.o blkverify.o > >>-block-obj-y += snapshot.o qapi.o > >>+block-obj-y += snapshot.o qapi.o json.o > >> block-obj-$(CONFIG_WIN32) += raw-win32.o win32-aio.o > >> block-obj-$(CONFIG_POSIX) += raw-posix.o > >> block-obj-$(CONFIG_LINUX_AIO) += 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 modify > >>+ * 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 <http://www.gnu.org/licenses/>. > >>+ */ > >>+ > >>+#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 driver"); > >>+ return; > >>+ } > >>+ > >>+ file_options_obj = qobject_from_json(filename); > >>+ if (!file_options_obj) { > >>+ error_setg(errp, "Could not parse the JSON options"); > >>+ return; > >>+ } > >>+ > >>+ if (qobject_type(file_options_obj) != QTYPE_QDICT) { > >>+ qobject_decref(file_options_obj); > >>+ error_setg(errp, "Invalid JSON object"); > >>+ return; > >>+ } > >>+ > >>+ full_options = 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) == 0); > >>+ QDECREF(full_options); > >>+} > >>+ > >>+static int json_open(BlockDriverState *bs, QDict *options, int flags, > >>+ Error **errp) > >>+{ > >>+ int ret; > >>+ > >>+ assert(bs->file == NULL); > >>+ ret = bdrv_open_image(&bs->file, NULL, options, "x-options", flags, > >>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 writing "ret = foo(); if (ret < 0) { return ret; / goto fail; }" > that I didn't notice. ;-) > > >>+} > >>+ > >>+static void json_close(BlockDriverState *bs) > >>+{ > >>+} > >>+ > >>+static BlockDriverAIOCB *json_aio_readv(BlockDriverState *bs, > >>+ int64_t sector_num, QEMUIOVector > >>*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, QEMUIOVector > >>*qiov, > >>+ int nb_sectors, > >>+ BlockDriverCompletionFunc *cb, > >>+ 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 = 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 = { > >>+ .format_name = "json", > >>+ .protocol_name = "json", > >>+ .instance_size = 0, > >>+ > >>+ .bdrv_parse_filename = json_parse_filename, > >>+ .bdrv_file_open = json_open, > >>+ .bdrv_close = json_close, > >>+ > >>+ .bdrv_aio_readv = json_aio_readv, > >>+ .bdrv_aio_writev = json_aio_writev, > >>+ > >>+ .has_variable_length = true, > >>+ .bdrv_getlength = json_getlength, > >>+ > >>+ .bdrv_refresh_limits = json_refresh_limits, > >>+ .bdrv_get_info = json_get_info, > >>+ > >>+ .authorizations = { true, true }, > >Paolo make rewrite the snapshot authorization code. > >In the new version you need > > .is_filter = true; > > .bdrv_recurse_is_first_children = your_implementation; > > > >I don't know when these patchset will be reviewed and merged so maybe this > >version is correct. > > I'll just rebase on top of Paolo's series then.
It's a sugestion made by Paolo. I wrote the actual code. The series is : "[PATCH] Rewrite block filter snapshot authorization mechanism" > > > Thanks, > > Max > > >>+}; > >>+ > >>+static void bdrv_json_init(void) > >>+{ > >>+ bdrv_register(&bdrv_json); > >>+} > >>+ > >>+block_init(bdrv_json_init); > >>-- > >>1.9.0 > >> > >> > >