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authorAnthony PERARD <anthony.perard@citrix.com>2017-11-16 15:14:19 +0000
committerJuan Quintela <quintela@redhat.com>2017-11-21 19:42:26 +0100
commit5d6c599fe1d69a1bf8c5c4d3c58be2b31cd625ad (patch)
treee23fa6670aed9cfb31ee9b48d48aec4aff46a7c9
parenta15d835f00dce270fd3194e83d9910f4b5b44ac0 (diff)
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migration, xen: Fix block image lock issue on live migration
When doing a live migration of a Xen guest with libxl, the images for block devices are locked by the original QEMU process, and this prevent the QEMU at the destination to take the lock and the migration fail. >From QEMU point of view, once the RAM of a domain is migrated, there is two QMP commands, "stop" then "xen-save-devices-state", at which point a new QEMU is spawned at the destination. Release locks in "xen-save-devices-state" so the destination can takes them, if it's a live migration. This patch add the "live" parameter to "xen-save-devices-state" which default to true so older version of libxenlight can work with newer version of QEMU. Signed-off-by: Anthony PERARD <anthony.perard@citrix.com> Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Reviewed-by: Juan Quintela <quintela@redhat.com> Signed-off-by: Juan Quintela <quintela@redhat.com>
-rw-r--r--migration/savevm.c23
-rw-r--r--qapi/migration.json6
2 files changed, 27 insertions, 2 deletions
diff --git a/migration/savevm.c b/migration/savevm.c
index 192f2d8..b7908f6 100644
--- a/migration/savevm.c
+++ b/migration/savevm.c
@@ -2242,13 +2242,20 @@ int save_snapshot(const char *name, Error **errp)
return ret;
}
-void qmp_xen_save_devices_state(const char *filename, Error **errp)
+void qmp_xen_save_devices_state(const char *filename, bool has_live, bool live,
+ Error **errp)
{
QEMUFile *f;
QIOChannelFile *ioc;
int saved_vm_running;
int ret;
+ if (!has_live) {
+ /* live default to true so old version of Xen tool stack can have a
+ * successfull live migration */
+ live = true;
+ }
+
saved_vm_running = runstate_is_running();
vm_stop(RUN_STATE_SAVE_VM);
global_state_store_running();
@@ -2263,6 +2270,20 @@ void qmp_xen_save_devices_state(const char *filename, Error **errp)
qemu_fclose(f);
if (ret < 0) {
error_setg(errp, QERR_IO_ERROR);
+ } else {
+ /* libxl calls the QMP command "stop" before calling
+ * "xen-save-devices-state" and in case of migration failure, libxl
+ * would call "cont".
+ * So call bdrv_inactivate_all (release locks) here to let the other
+ * side of the migration take controle of the images.
+ */
+ if (live && !saved_vm_running) {
+ ret = bdrv_inactivate_all();
+ if (ret) {
+ error_setg(errp, "%s: bdrv_inactivate_all() failed (%d)",
+ __func__, ret);
+ }
+ }
}
the_end:
diff --git a/qapi/migration.json b/qapi/migration.json
index bbc4671..03f57c9 100644
--- a/qapi/migration.json
+++ b/qapi/migration.json
@@ -1075,6 +1075,9 @@
# data. See xen-save-devices-state.txt for a description of the binary
# format.
#
+# @live: Optional argument to ask QEMU to treat this command as part of a live
+# migration. Default to true. (since 2.11)
+#
# Returns: Nothing on success
#
# Since: 1.1
@@ -1086,7 +1089,8 @@
# <- { "return": {} }
#
##
-{ 'command': 'xen-save-devices-state', 'data': {'filename': 'str'} }
+{ 'command': 'xen-save-devices-state',
+ 'data': {'filename': 'str', '*live':'bool' } }
##
# @xen-set-replication: