From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:49882) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Zbl7p-00008p-R7 for qemu-devel@nongnu.org; Tue, 15 Sep 2015 03:58:03 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1Zbl7m-0007yL-Hy for qemu-devel@nongnu.org; Tue, 15 Sep 2015 03:58:01 -0400 References: <1441878905-5272-1-git-send-email-wency@cn.fujitsu.com> <1441878905-5272-5-git-send-email-wency@cn.fujitsu.com> <87mvwpkqzi.fsf@blackfin.pond.sub.org> <55F7850A.5050109@cn.fujitsu.com> <87613c86mk.fsf@blackfin.pond.sub.org> From: Wen Congyang Message-ID: <55F7CF5B.4070707@cn.fujitsu.com> Date: Tue, 15 Sep 2015 15:57:15 +0800 MIME-Version: 1.0 In-Reply-To: <87613c86mk.fsf@blackfin.pond.sub.org> Content-Type: text/plain; charset="windows-1252" Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH v3 4/5] qmp: add monitor command to add/remove a child List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Markus Armbruster Cc: Kevin Wolf , Alberto Garcia , zhanghailiang , qemu block , Jiang Yunhong , Dong Eddie , qemu devel , "Dr. David Alan Gilbert" , Gonglei , Stefan Hajnoczi , Yang Hongyang On 09/15/2015 03:49 PM, Markus Armbruster wrote: > Wen Congyang writes: > >> On 09/14/2015 10:36 PM, Markus Armbruster wrote: >>> Wen Congyang writes: >>> >>>> Signed-off-by: Wen Congyang >>>> Signed-off-by: zhanghailiang >>>> Signed-off-by: Gonglei >>>> --- >>>> blockdev.c | 47 ++++++++++++++++++++++++++++++++++++++++++++++ >>>> qapi/block-core.json | 34 +++++++++++++++++++++++++++++++++ >>>> qmp-commands.hx | 53 ++++++++++++++++++++++++++++++++++++++++++++++++++++ >>>> 3 files changed, 134 insertions(+) >>>> >>>> diff --git a/blockdev.c b/blockdev.c >>>> index bd47756..0a40607 100644 >>>> --- a/blockdev.c >>>> +++ b/blockdev.c >>>> @@ -3413,6 +3413,53 @@ fail: >>>> qmp_output_visitor_cleanup(ov); >>>> } >>>> >>>> +void qmp_x_child_add(const char *parent, const char *child, >>>> + Error **errp) >>>> +{ >>>> + BlockDriverState *parent_bs, *child_bs; >>>> + Error *local_err = NULL; >>>> + >>>> + parent_bs = bdrv_lookup_bs(parent, parent, &local_err); >>>> + if (!parent_bs) { >>>> + error_propagate(errp, local_err); >>>> + return; >>>> + } >>>> + >>>> + child_bs = bdrv_find_node(child); >>>> + if (!child_bs) { >>>> + error_setg(errp, "Node '%s' not found", child); >>>> + return; >>>> + } >>>> + >>>> + bdrv_add_child(parent_bs, child_bs, &local_err); >>>> + if (local_err) { >>>> + error_propagate(errp, local_err); >>>> + } >>>> +} >>>> + >>>> +void qmp_child_del(const char *parent, const char *child, Error **errp) >>>> +{ >>>> + BlockDriverState *parent_bs, *child_bs; >>>> + Error *local_err = NULL; >>>> + >>>> + parent_bs = bdrv_lookup_bs(parent, parent, &local_err); >>>> + if (!parent_bs) { >>>> + error_propagate(errp, local_err); >>>> + return; >>>> + } >>>> + >>>> + child_bs = bdrv_find_node(child); >>>> + if (!child_bs) { >>>> + error_setg(errp, "Node '%s' not found", child); >>>> + return; >>>> + } >>>> + >>>> + bdrv_del_child(parent_bs, child_bs, &local_err); >>>> + if (local_err) { >>>> + error_propagate(errp, local_err); >>>> + } >>>> +} >>>> + >>>> BlockJobInfoList *qmp_query_block_jobs(Error **errp) >>>> { >>>> BlockJobInfoList *head = NULL, **p_next = &head; >>>> diff --git a/qapi/block-core.json b/qapi/block-core.json >>>> index e68a59f..b959577 100644 >>>> --- a/qapi/block-core.json >>>> +++ b/qapi/block-core.json >>>> @@ -2272,3 +2272,37 @@ >>>> ## >>>> { 'command': 'block-set-write-threshold', >>>> 'data': { 'node-name': 'str', 'write-threshold': 'uint64' } } >>>> + >>>> +## >>>> +# @x-child-add >>>> +# >>>> +# Add a new child to the parent BDS. Currently only the Quorum driver >>>> +# implements this feature. This is useful to fix a broken quorum child. >>>> +# >>>> +# @parent: graph node name or id which the child will be added to. >>>> +# >>>> +# @child: graph node name that will be added. >>>> +# >>>> +# Note: this command is experimental, and not a stable API. >>>> +# >>>> +# Since: 2.5 >>>> +## >>>> +{ 'command': 'x-child-add', >>>> + 'data' : { 'parent': 'str', 'child': 'str' } } >>>> + >>>> +## >>>> +# @child-del >>>> +# >>>> +# Remove a child from the parent BDS. Currently only the Quorum driver >>>> +# implements this feature. This is useful to fix a broken quorum child. >>>> +# Note, you can't remove a child if it would bring the quorum below its >>>> +# threshold. >>>> +# >>>> +# @parent: graph node name or id from which the child will removed. >>>> +# >>>> +# @child: graph node name that will be removed. >>>> +# >>>> +# Since: 2.5 >>>> +## >>>> +{ 'command': 'child-del', >>>> + 'data' : { 'parent': 'str', 'child': 'str' } } >>> >>> Why is x-child-add experimental, but child-del isn't? Please explain >>> both in the schema and in the commit message. >> >> No special reason. Should I put child-del in experimental namespace? > > I found the reason for x-child-add in your v2: > > child-add > ------------ > > Add a child to a quorum node. > > This command is still a work in progress. It doesn't support all > block drivers. Stay away from it unless you want it to help with > its development. > > Eric suggested to rename it to x-child-add, and you did. Good. You > also shortened the "work in progress" note to just "Note: this command > is experimental, and not a stable API." I'd like to have a more verbose > note explaining *why* the command is experimental, both here and in > qmp-commands.hx. "It doesn't support all block drivers" is a reason. > Are the any others? Currently, it only for quorum. But in the future, we can use this command to do more thing. For example: bs->file, bs->backing_hd, ... > > Is child-del similarly unfinished? If yes, make it x-child-del to save > us from later grief. > > If no: is child-del is only useful together with x-child-add? Then make > it x-child-del regardless. child-del is only useful together with x-child-add. I will rename it to x-child-del in the next version. Thanks Wen Congyang > >>>> diff --git a/qmp-commands.hx b/qmp-commands.hx >>>> index 495670b..139a23b 100644 >>>> --- a/qmp-commands.hx >>>> +++ b/qmp-commands.hx >>>> @@ -4053,6 +4053,59 @@ Example: >>>> EQMP >>>> >>>> { >>>> + .name = "x-child-add", >>>> + .args_type = "parent:B,child:B", >>>> + .mhandler.cmd_new = qmp_marshal_input_x_child_add, >>>> + }, >>>> + >>>> +SQMP >>>> +x-child-add >>>> +------------ >>>> + >>>> +Add a child to a quorum node. >>>> + >>>> +Arguments: >>>> + >>>> +- "parent": the quorum's id or node name >>>> +- "child": the child node-name which will be added >>> >>> Node name parameters are usually named node-name or, if there's more >>> than one, FOO-node-name. Unless we want to abandon that convention, >>> this should therefore be node-name and child-node-name, or parent-node >>> name and child-node-name. >> >> parent can be top BDS, so it can be id. node-name is a very common name, >> and I think child or child-node-name is better. > > Kevin pointed out we want to move to names without a -node-name suffix. > >>>> + >>>> +Note: this command is experimental, and not a stable API. >>>> + >>>> +Example: >>>> + >>>> +-> { "execute": "x-child-add", >>>> + "arguments": { "parent": "disk1", "child": "new_node" } } >>>> +<- { "return": {} } >>>> + >>>> +EQMP >>>> + >>>> + { >>>> + .name = "child-del", >>> >>> Documentation and schema have x-child-add, actual command is child-add. >>> Oops. >> >> Here is child-del.... > > You're right. I got confused... > >>>> + .args_type = "parent:B,child:B", >>>> + .mhandler.cmd_new = qmp_marshal_input_child_del, >>>> + }, >>>> + >>>> +SQMP >>>> +child-del >>>> +------------ >>>> + >>>> +Delete a child from a quorum node. It can be used to remove a broken >>>> +quorum child. >>>> + >>>> +Arguments: >>>> + >>>> +- "parent": the quorum's id or node name >>>> +- "child": the child node-name which will be removed >>> >>> Same comment as on x-child-add's parameter names. >>> >>>> + >>>> +Example: >>>> + >>>> +-> { "execute": "child-del", >>>> + "arguments": { "parent": "disk1", "child": "new_node" } } >>>> +<- { "return": {} } >>>> + >>>> +EQMP >>>> + >>>> + { >>>> .name = "query-named-block-nodes", >>>> .args_type = "", >>>> .mhandler.cmd_new = qmp_marshal_input_query_named_block_nodes, >>> . >>> > . >