On Mon, Jan 12, 2026 at 11:29:24 +0100, Markus Armbruster wrote: > Peter Krempa <[email protected]> writes: > > > From: Peter Krempa <[email protected]> > > > > Some time ago (commit facda5443f5a8) I've added 'flat' mode (which > > omits 'backing-image' key in reply) to 'query-named-block-nodes' to > > minimize the size of the returned JSON for deeper backing chains. > > Almost six years. Time flies :)
Indeed! Actually last year (already) I've deleted the corresponding capability since libvirt now only supports QEMUs which do support this :D > > > While 'query-block' behaved slightly better it turns out that in libvirt > > we do call 'query-block' to figure out some information about the > > block device (e.g. throttling info) but we don't look at the backing > > chain itself. > > > > Wire up 'flat' for 'query-block' so that libvirt can ask for an > > abbreviated output. The implementation is much simpler as the internals > > are shared with 'query-named-block-nodes'. > > > > Signed-off-by: Peter Krempa <[email protected]> > > --- > > block/monitor/block-hmp-cmds.c | 4 ++-- > > block/qapi.c | 9 +++++---- > > qapi/block-core.json | 4 ++++ > > ui/cocoa.m | 2 +- > > 4 files changed, 12 insertions(+), 7 deletions(-) > > > > diff --git a/block/monitor/block-hmp-cmds.c b/block/monitor/block-hmp-cmds.c > > index 3640d1f3dc..d301f56a39 100644 > > --- a/block/monitor/block-hmp-cmds.c > > +++ b/block/monitor/block-hmp-cmds.c > > @@ -422,7 +422,7 @@ void hmp_nbd_server_start(Monitor *mon, const QDict > > *qdict) > > /* Then try adding all block devices. If one fails, close all and > > * exit. > > */ > > - block_list = qmp_query_block(NULL); > > + block_list = qmp_query_block(false, false, NULL); > > Is info->value->inserted->image->backing_image used here? > > If not, we can pass true and save allocations. Thought, not a demand. It's not used in hmp_nbd_server_start. I'll do a separate patch for it as it's simple enough, but IMO not related to this patch which should keep behaviour of unrelated code. > Same for the other calls. > > > > > for (info = block_list; info; info = info->next) { > > if (!info->value->inserted) { > > @@ -741,7 +741,7 @@ void hmp_info_block(Monitor *mon, const QDict *qdict) ... but this one does use it (although for questionably useful information: first backing image name and the depth of the backing chain). [...] > > diff --git a/qapi/block-core.json b/qapi/block-core.json > > index b82af74256..e89d878544 100644 > > --- a/qapi/block-core.json > > +++ b/qapi/block-core.json > > @@ -855,6 +855,9 @@ > > # > > # Get a list of `BlockInfo` for all virtual block devices. > > # > > +# @flat: Omit the nested data about backing image ("backing-image" > > +# key) if true. Default is false (Since 11.0) > > +# > > The "backing-image" key is actually BlockInfo member inserted member > image member backing-image. This is even more deeply nested than for > query-named-block-nodes. Doc text good enough? Hmm, how about: +# @flat: Omit the nested data about backing image (Omitted are contents of +# 'backing-image' key of the 'ImageInfo' struct which is returned +# as 'image' key of 'BlockDeviceInfo' struct returned as 'inserted' key +# in 'BlockInfo' struct returned by this command). or +# @flat: Omit the nested data about backing image (Omitted are contents +# of 'BlockInfo'->inserted->image->backing-image). ?
