Re: [libvirt] [PATCHv3 06/10] Widening API change - accept empty path for virDomainBlockStats

And provide domain summary stat in that case, for lxc backend. Use case is a container inheriting all devices from the host, e.g. when doing application containerization. --- src/libvirt.c | 8 ++++++-- tools/virsh-domain-monitor.c | 11 ++++++++--- tools/virsh.pod | 5 +++-- 3 files changed, 17 insertions(+), 7 deletions(-)

diff --git a/src/libvirt.c b/src/libvirt.c index 9cc5b1c..64da438 100644 --- a/src/libvirt.c +++ b/src/libvirt.c @@ -7747,7 +7747,9 @@ error: * an unambiguous source name of the block device (the <source * file='...'/> sub-element, such as "/path/to/image"). Valid names * can be found by calling virDomainGetXMLDesc() and inspecting - * elements within //domain/devices/disk. + * elements within //domain/devices/disk. Some drivers might also + * accept the empty string for the @disk parameter, and then yield + * summary stats for the entire domain. * * Domains may have more than one block device. To get stats for * each you should make multiple calls to this function. @@ -7813,7 +7815,9 @@ error: * an unambiguous source name of the block device (the <source * file='...'/> sub-element, such as "/path/to/image"). Valid names * can be found by calling virDomainGetXMLDesc() and inspecting - * elements within //domain/devices/disk. + * elements within //domain/devices/disk. Some drivers might also + * accept the empty string for the @disk parameter, and then yield + * summary stats for the entire domain. * * Domains may have more than one block device. To get stats for * each you should make multiple calls to this function. diff --git a/tools/virsh-domain-monitor.c b/tools/virsh-domain-monitor.c index de4afbb..105f841 100644 --- a/tools/virsh-domain-monitor.c +++ b/tools/virsh-domain-monitor.c @@ -888,7 +888,7 @@ static const vshCmdOptDef opts_domblkstat[] = { }, {.name = "device", .type = VSH_OT_DATA, - .flags = VSH_OFLAG_REQ, + .flags = VSH_OFLAG_EMPTY_OK, .help = N_("block device") }, {.name = "human", @@ -954,8 +954,13 @@ cmdDomblkstat(vshControl *ctl, const vshCmd *cmd) if (!(dom = vshCommandOptDomain(ctl, cmd, &name))) return false; - if (vshCommandOptStringReq(ctl, cmd, "device", &device) < 0) - goto cleanup; + /* device argument is optional now. if it's missing, supply empty + string to denote 'all devices'. A NULL device arg would violate + API contract. + */ + rc = vshCommandOptStringReq(ctl, cmd, "device", &device); /* and ignore rc */ + if (!device) + device = ""; rc = virDomainBlockStatsFlags(dom, device, NULL, &nparams, 0); diff --git a/tools/virsh.pod b/tools/virsh.pod index 9e670da..3e45177 100644 --- a/tools/virsh.pod +++ b/tools/virsh.pod @@ -623,12 +623,13 @@ If I<--graceful> is specified, don't resort to extreme measures (e.g. SIGKILL) when the guest doesn't stop after a reasonable timeout; return an error instead. -=item B<domblkstat> I<domain> I<block-device> [I<--human>] +=item B<domblkstat> I<domain> [I<block-device>] [I<--human>] Get device block stats for a running domain. A I<block-device> corresponds to a unique target name (<target dev='name'/>) or source file (<source file='name'/>) for one of the disk devices attached to I<domain> (see -also B<domblklist> for listing these names). +also B<domblklist> for listing these names). On a lxc domain, omitting the +I<block-device> yields device block stats summarily for the entire domain. Use I<--human> for a more human readable output.