[libvirt] [PATCH] migration: do not restore labels on failed migration

https://bugzilla.redhat.com/show_bug.cgi?id=822052 When doing a live migration, if the destination fails for any reason after the point in which files should be labeled, then the cleanup of the destination would restore the labels to their defaults, even though the source is still trying to continue running with the image open. Bug 822052 mentioned one source of live migration failure - a mismatch in SELinux virt_use_nfs settings (on for source, off for destination); but I found other situations that would also trigger it (for example, having a graphics device tied to port 5999 on the source, and a different domain on the destination already using that port, so that the destination cannot reuse the port). In short, just as cleanup of the source on a successful migration must not relabel files (because the destination would be crippled by the relabel), cleanup of the destination on a failed migraion must not relabel files (because the source would be crippled). * src/qemu/qemu_process.c (qemuProcessStart): Set flag to avoid label restoration when cleaning up on failed migration. Signed-off-by: Eric Blake <eblake(a)redhat.com&gt; --- src/qemu/qemu_process.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/src/qemu/qemu_process.c b/src/qemu/qemu_process.c index 31de759..d727fc4 100644 --- a/src/qemu/qemu_process.c +++ b/src/qemu/qemu_process.c @@ -3466,6 +3466,10 @@ int qemuProcessStart(virConnectPtr conn, * restore any security label as we would overwrite labels * we did not set. */ stop_flags = VIR_QEMU_PROCESS_STOP_NO_RELABEL; + /* If we fail while doing incoming migration, then we must not + * relabel, as the source is still using the files. */ + if (migrateFrom) + stop_flags |= VIR_QEMU_PROCESS_STOP_MIGRATED; hookData.conn = conn; hookData.vm = vm; -- 1.8.3.1