On 01/17/2014 08:31 AM, Francesco Romani wrote:
This patch add an element to QEMU's capability XML, to
s/add/adds/
show if the underlying QEMU binary supports the live disk snapshotting or not. This allow any client to know ahead of time if the feature
s/allow/allows/
is available.
Without this information available, the only way to check for the snapshot support is to request one and check for errors.
Signed-off-by: Francesco Romani <fromani@redhat.com> --- docs/schemas/capability.rng | 6 ++++++ src/qemu/qemu_capabilities.c | 7 +++++++ 2 files changed, 13 insertions(+)
It would probably also be good to test this in tests/capabilityschemadata/, but maybe that happens later in the series...
</optional> + <optional> + <element name='disksnapshot'>
Existing capabilities have an interesting mix of spelling: underscores: <os_type>, squashed: <baselabel>, camelCase: <machine maxCpus=''>. I would have problaby picked <disk-snapshot> if I were writing it without knowledge of pre-existing code, but don't see any examples of that. So, your naming is probably as good as any.
+++ b/src/qemu/qemu_capabilities.c @@ -687,6 +687,7 @@ virQEMUCapsInitGuest(virCapsPtr caps, virQEMUCapsPtr qemubinCaps = NULL; virQEMUCapsPtr kvmbinCaps = NULL; int ret = -1; + bool hasdisksnapshot = false;
/* Check for existence of base emulator, or alternate base * which can be used with magic cpu choice @@ -774,6 +775,12 @@ virQEMUCapsInitGuest(virCapsPtr caps, !virCapabilitiesAddGuestFeature(guest, "deviceboot", 1, 0))
That, and you were copying from 'deviceboot' which also uses squashed style.
goto error;
+ if (virQEMUCapsGet(qemubinCaps, QEMU_CAPS_DISK_SNAPSHOT)) + hasdisksnapshot = true; + + if (!virCapabilitiesAddGuestFeature(guest, "disksnapshot", hasdisksnapshot, 0)) + goto error;
I probably would have skipped the temporary variable, but then hit longer line length: if (!virCapabilitiesAddGuestFeature(guest, "disksnapshot", virQEMUCapsGet(qemubinCaps, QEMU_CAPS_DISK_SNAPSHOT)), 0)) goto error; so your way is fine as-is. Preliminary ACK, assuming the rest of the series covers testing and documentation (and as you said in the cover letter, existing docs are a bit sparse). -- Eric Blake eblake redhat com +1-919-301-3266 Libvirt virtualization library http://libvirt.org