On 7/20/22 12:05 PM, Eugenio Pérez wrote:
since qemu 6.0, if migration is blocked for some reason, 'query-migrate' will return an array of error strings describing the migration blockers. This can be used to check whether there are any devices blocking migration, etc.
Enable qemuMigrationSrcIsAllowed to query it.
I reworded the commit log message a bit. Rather than repeating it here, I'll just point you to the branch I pushed to gitlab (link in my response to the cover letter).
Signed-off-by: Eugenio Pérez <eperezma@redhat.com> Reviewed-by: Jiri Denemark <jdenemar@redhat.com> --- v4: * Do not override qemuDomainGetMigrationBlockers error calling again virReportError. * Replace ", " with "; " in blockers separators.
v3: * Report message with a colon. * Report all blockers instead of only the first. --- src/qemu/qemu_migration.c | 30 ++++++++++++++++++++++++++++++ 1 file changed, 30 insertions(+)
diff --git a/src/qemu/qemu_migration.c b/src/qemu/qemu_migration.c index b12cb518ee..2e3044289a 100644 --- a/src/qemu/qemu_migration.c +++ b/src/qemu/qemu_migration.c @@ -1414,6 +1414,20 @@ qemuMigrationSrcIsAllowedHostdev(const virDomainDef *def) return true; }
+static int +qemuDomainGetMigrationBlockers(virQEMUDriver *driver, + virDomainObj *vm, + char ***blockers) +{ + qemuDomainObjPrivate *priv = vm->privateData; + int rc; + + qemuDomainObjEnterMonitor(driver, vm); + rc = qemuMonitorGetMigrationBlockers(priv->mon, blockers); + qemuDomainObjExitMonitor(vm); + + return rc; +}
Note that we've been trying to keep 2 blank lines between each function, but here you've added a new function in between those 2 blank lines, so there's only a single blank before and after. I added in the extra blanks.
/** * qemuMigrationSrcIsAllowed: @@ -1439,6 +1453,22 @@ qemuMigrationSrcIsAllowed(virQEMUDriver *driver, int nsnapshots; int pauseReason; size_t i; + int r; + + /* Ask qemu if it have a migration blocker */
"has a migration blocker"
+ if (virQEMUCapsGet(priv->qemuCaps, QEMU_CAPS_MIGRATION_BLOCKED_REASONS)) { + g_auto(GStrv) blockers = NULL; + r = qemuDomainGetMigrationBlockers(driver, vm, &blockers); + if (r != 0) + return false;
in libvirt we usually return -1 on failure, and check with "if (r < 0)". And since that is the only use of "r", we prefer to not have the extra stack variable cluttering things up, so: if (qemuDomainGetMigrationBlockers(driver, vm, &blockers) < 0) return false;
+ + if (blockers && blockers[0]) { + g_autofree char *reasons = g_strjoinv("; ", blockers); + virReportError(VIR_ERR_OPERATION_INVALID, + _("cannot migrate domain: %s"), reasons); + return false; + } + }
/* perform these checks only when migrating to remote hosts */ if (remote) {