[libvirt] [PATCH v1] qemu-migration: Disallow migration of read only disk

From: "Corey S. McQuay" <csmcquay(a)linux.vnet.ibm.com&gt; Currently Libvirt allows attempts to migrate read only disks. Qemu cannot handle this as read only disks cannot be written to on the destination system. The end result is a cryptic error message and a failed migration. This patch causes migration to fail earlier and provides a meaningful error message stating that migrating read only disks is not supported. Signed-off-by: Corey S. McQuay <csmcquay(a)linux.vnet.ibm.com&gt; Reviewed-by: Jason J. Herne <jjherne(a)linux.vnet.ibm.com&gt; Reviewed-by: Boris Fiuczynski <fiuczy(a)linux.vnet.ibm.com&gt; --- src/qemu/qemu_migration.c | 25 +++++++++++++++++++++++++ 1 file changed, 25 insertions(+) diff --git a/src/qemu/qemu_migration.c b/src/qemu/qemu_migration.c index d018add..7d0a78f 100644 --- a/src/qemu/qemu_migration.c +++ b/src/qemu/qemu_migration.c @@ -2387,6 +2387,28 @@ qemuMigrationIsSafe(virDomainDefPtr def, return true; } +static bool +qemuMigrationAreAllDisksRW(virDomainDefPtr def, + size_t nmigrate_disks, + const char **migrate_disks) +{ + size_t i; + + for (i = 0; i < def->ndisks; i++) { + virDomainDiskDefPtr disk = def->disks[i]; + + if (qemuMigrateDisk(disk, nmigrate_disks, migrate_disks) && + disk->src->readonly) { + virReportError(VIR_ERR_OPERATION_UNSUPPORTED, + _("Cannot migrate read-only disk %s"), + disk->dst); + return false; + } + } + + return true; +} + /** qemuMigrationSetOffline * Pause domain for non-live migration. */ @@ -3132,6 +3154,9 @@ qemuMigrationBeginPhase(virQEMUDriverPtr driver, !qemuMigrationIsSafe(vm->def, nmigrate_disks, migrate_disks)) goto cleanup; + if (!qemuMigrationAreAllDisksRW(vm->def, nmigrate_disks, migrate_disks)) + goto cleanup; + if (flags & VIR_MIGRATE_POSTCOPY && (!(flags & VIR_MIGRATE_LIVE) || flags & VIR_MIGRATE_PAUSED)) { -- 1.8.3.1