From abb21ac3e602430bd7a35e88ecc2eb62c91c7b42 Mon Sep 17 00:00:00 2001 From: Kevin Wolf Date: Tue, 23 Feb 2016 17:33:24 +0100 Subject: hmp: 'drive_add -n' for creating a node without BB This patch adds an option to the drive_add HMP command to create only a BlockDriverState without a BlockBackend on top. The motivation for this is that libvirt needs to specify options to a migration target (specifically, detect-zeroes). drive-mirror doesn't allow specifying options, and the proper way to do this is to create the target BDS separately with blockdev-add (where you can specify options) and then use blockdev-mirror to that BDS. However, libvirt can't use blockdev-add as long as it is still experimental, and we're expecting that it will still take some time, so we need to resort to drive_add. The problem with drive_add is that so far it always created a BB, and BDSes with a BB can't be used as a mirroring target as long as we don't support multiple BBs per BDS - and while we're working towards that goal, it's another thing that will still take some time. So to achieve the goal, the simplest solution to provide the functionality now without adding one-off options to the mirror QMP commands is to extend drive_add to create nodes without BBs. Signed-off-by: Kevin Wolf --- device-hotplug.c | 7 +++++++ 1 file changed, 7 insertions(+) (limited to 'device-hotplug.c') diff --git a/device-hotplug.c b/device-hotplug.c index 9a7cd669d5..3e5cdaad10 100644 --- a/device-hotplug.c +++ b/device-hotplug.c @@ -30,6 +30,7 @@ #include "qemu/config-file.h" #include "sysemu/sysemu.h" #include "monitor/monitor.h" +#include "block/block_int.h" static DriveInfo *add_init_drive(const char *optstr) { @@ -55,6 +56,12 @@ void hmp_drive_add(Monitor *mon, const QDict *qdict) { DriveInfo *dinfo = NULL; const char *opts = qdict_get_str(qdict, "opts"); + bool node = qdict_get_try_bool(qdict, "node", false); + + if (node) { + hmp_drive_add_node(mon, opts); + return; + } dinfo = add_init_drive(opts); if (!dinfo) { -- cgit v1.2.3