Re: [libvirt] [Qemu-devel] [PATCH 2/2] qapi: deprecate implicit filters

Am 14.08.2019 um 21:27 hat John Snow geschrieben: > > > On 8/14/19 6:07 AM, Vladimir Sementsov-Ogievskiy wrote: >> To get rid of implicit filters related workarounds in future let's >> deprecate them now. >> >> Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov(a)virtuozzo.com&gt; >> --- >> qemu-deprecated.texi | 7 +++++++ >> qapi/block-core.json | 6 ++++-- >> include/block/block_int.h | 10 +++++++++- >> blockdev.c | 10 ++++++++++ >> 4 files changed, 30 insertions(+), 3 deletions(-) >> >> diff --git a/qemu-deprecated.texi b/qemu-deprecated.texi >> index 2753fafd0b..8222440148 100644 >> --- a/qemu-deprecated.texi >> +++ b/qemu-deprecated.texi >> @@ -183,6 +183,13 @@ the 'wait' field, which is only applicable to sockets in server mode >> >> Use blockdev-mirror and blockdev-backup instead. >> >> +@subsection implicit filters (since 4.2) >> + >> +Mirror and commit jobs inserts filters, which becomes implicit if user >> +omitted filter-node-name parameter. So omitting it is deprecated, set it >> +always. Note, that drive-mirror don't have this parameter, so it will >> +create implicit filter anyway, but drive-mirror is deprecated itself too. >> + >> @section Human Monitor Protocol (HMP) commands >> >> @subsection The hub_id parameter of 'hostfwd_add' / 'hostfwd_remove' (since 3.1) >> diff --git a/qapi/block-core.json b/qapi/block-core.json >> index 4e35526634..0505ac9d8b 100644 >> --- a/qapi/block-core.json >> +++ b/qapi/block-core.json >> @@ -1596,7 +1596,8 @@ >> # @filter-node-name: the node name that should be assigned to the >> # filter driver that the commit job inserts into the graph >> # above @top. If this option is not given, a node name is >> -# autogenerated. (Since: 2.9) >> +# autogenerated. Omitting this option is deprecated, it will >> +# be required in future. (Since: 2.9) >> # >> # @auto-finalize: When false, this job will wait in a PENDING state after it has >> # finished its work, waiting for @block-job-finalize before >> @@ -2249,7 +2250,8 @@ >> # @filter-node-name: the node name that should be assigned to the >> # filter driver that the mirror job inserts into the graph >> # above @device. If this option is not given, a node name is >> -# autogenerated. (Since: 2.9) >> +# autogenerated. Omitting this option is deprecated, it will >> +# be required in future. (Since: 2.9) >> # >> # @copy-mode: when to copy data to the destination; defaults to 'background' >> # (Since: 3.0) >> diff --git a/include/block/block_int.h b/include/block/block_int.h >> index 3aa1e832a8..624da0b4a2 100644 >> --- a/include/block/block_int.h >> +++ b/include/block/block_int.h >> @@ -762,7 +762,15 @@ struct BlockDriverState { >> bool sg; /* if true, the device is a /dev/sg* */ >> bool probed; /* if true, format was probed rather than specified */ >> bool force_share; /* if true, always allow all shared permissions */ >> - bool implicit; /* if true, this filter node was automatically inserted */ >> + >> + /* >> + * @implicit field is deprecated, don't set it to true for new filters. >> + * If true, this filter node was automatically inserted and user don't >> + * know about it and unprepared for any effects of it. So, implicit >> + * filters are workarounded and skipped in many places of the block >> + * layer code. >> + */ >> + bool implicit; >> >> BlockDriver *drv; /* NULL means no media */ >> void *opaque; >> diff --git a/blockdev.c b/blockdev.c >> index 36e9368e01..b3cfaccce1 100644 >> --- a/blockdev.c >> +++ b/blockdev.c >> @@ -3292,6 +3292,11 @@ void qmp_block_commit(bool has_job_id, const char *job_id, const char *device, >> BlockdevOnError on_error = BLOCKDEV_ON_ERROR_REPORT; >> int job_flags = JOB_DEFAULT; >> >> + if (!has_filter_node_name) { >> + warn_report("Omitting filter-node-name parameter is deprecated, it " >> + "will be required in future"); >> + } >> + >> if (!has_speed) { >> speed = 0; >> } >> @@ -3990,6 +3995,11 @@ void qmp_blockdev_mirror(bool has_job_id, const char *job_id, >> Error *local_err = NULL; >> int ret; >> >> + if (!has_filter_node_name) { >> + warn_report("Omitting filter-node-name parameter is deprecated, it " >> + "will be required in future"); >> + } >> + >> bs = qmp_get_root_bs(device, errp); >> if (!bs) { >> return; >> > > This might be OK to do right away, though. > > I asked Markus this not too long ago; do we want to amend the QAPI > schema specification to allow commands to return with "Warning" strings, > or "Deprecated" stings to allow in-band deprecation notices for cases > like these? > > example: > > { "return": {}, > "deprecated": True, > "warning": "Omitting filter-node-name parameter is deprecated, it will > be required in the future" > } > > There's no "error" key, so this should be recognized as success by > compatible clients, but they'll definitely see the extra information. > > Part of my motivation is to facilitate a more aggressive deprecation of > legacy features by ensuring that we are able to rigorously notify users > through any means that they need to adjust their scripts. Who would read this, though? In the best case it ends up deep in a libvirt log that nobody will look at because there was no error. In the more common case, the debug level is configured so that QMP traffic isn't even logged. Kevin