Am 29.03.2019 um 17:19 hat Markus Armbruster geschrieben:
> Markus Armbruster <arm...@redhat.com> writes:
>
> > Markus Armbruster <arm...@redhat.com> writes:
> >
> >> Markus Armbruster <arm...@redhat.com> writes:
> >>
> >>> Kevin Wolf <kw...@redhat.com> writes:
> >>>
> >>>> auto-read-only=on changed its behaviour in file-posix for the 4.0
> >>>> release.
> >>>
> >>> Commit hash, please.
> >>
> >> I guess it's commit 23dece19da4 "file-posix: Make auto-read-only
> >> dynamic".
> >>
> >>>> This change cannot be detected through the usual mechanisms
> >>>> like schema introspection. Add a new feature to query-qemu-features to
> >>>> allow libvirt to detect the presence of the new behaviour.
> >>>>
> >>>> Signed-off-by: Kevin Wolf <kw...@redhat.com>
> > [...]
> >> The "posix" in @file-posix-dynamic-auto-read-only feels weird. To make
> >> sense of it, you need to know on what kind of host QEMU runs. If we
> >> ever implement it for Windows hosts, we'd get do add
> >> @file-windows-posix-dynamic-auto-read-only.
> >>
> >> What about instead adding @file-dynamic-auto-read-only with a suitable
> >> compile-time conditional?
> >>
> >> [...]
> >
> > Incremental patch:
>
> Too fast, use this one.
>
> diff --git a/qapi/misc.json b/qapi/misc.json
> index df23c54a65..36b5ceb595 100644
> --- a/qapi/misc.json
> +++ b/qapi/misc.json
> @@ -3058,7 +3058,7 @@
> # Information about support for QEMU features that isn't available through
> # schema introspection.
> #
> -# @file-posix-dynamic-auto-read-only:
> +# @file-dynamic-auto-read-only:
> # true if auto-read-only=on means that the image file is dynamically
> reopened
> # read-only or read-write depending on whether any writers are attached to
> # the node.
> @@ -3066,7 +3066,9 @@
> # Since: 4.0
> ##
> { 'struct': 'QemuFeatures',
> - 'data': { 'file-posix-dynamic-auto-read-only': 'bool' } }
> + 'data': {
> + 'file-dynamic-auto-read-only': { 'type': 'bool',
> + 'if': 'defined(CONFIG_POSIX)' } } }
I don't think there is a good reason to make the field conditional. What
should be conditional is its value:
diff --git a/qapi/misc.json b/qapi/misc.json
index df23c54a65..a460fd2acc 100644
--- a/qapi/misc.json
+++ b/qapi/misc.json
@@ -3058,7 +3058,7 @@
# Information about support for QEMU features that isn't available through
# schema introspection.
#
-# @file-posix-dynamic-auto-read-only:
+# @file-dynamic-auto-read-only:
# true if auto-read-only=on means that the image file is dynamically reopened
# read-only or read-write depending on whether any writers are attached to
# the node.
@@ -3066,7 +3066,7 @@
# Since: 4.0
##
{ 'struct': 'QemuFeatures',
- 'data': { 'file-posix-dynamic-auto-read-only': 'bool' } }
+ 'data': { 'file-dynamic-auto-read-only': 'bool' } }
##
# @query-qemu-features:
diff --git a/qmp.c b/qmp.c
index 2a887c1e7d..3d3c300dc6 100644
--- a/qmp.c
+++ b/qmp.c
@@ -723,7 +723,11 @@ QemuFeatures *qmp_query_qemu_features(Error **errp)
QemuFeatures *caps = g_new(QemuFeatures, 1);
*caps = (QemuFeatures) {
- .file_posix_dynamic_auto_read_only = true,
+#ifdef CONFIG_POSIX
+ .file_dynamic_auto_read_only = true,
+#else
+ .file_dynamic_auto_read_only = false,
+#endif
};
return caps;
