[libvirt] [RFC PATCHv2 3/3] qemu: allow simple domain save to use fd: protocol

Work in progress - this fails for root-squash NFS, as well as for older qemu that don't support fd: migration, and doesn't cover compression coupled with migration. All of those need to be provided by a final solution. * src/qemu/qemu_driver.c (qemudDomainSaveFlag): Use new function when there is no compression. --- v2: new patch, provided for getting feedback on the approach src/qemu/qemu_driver.c | 16 +++++++++++++--- 1 files changed, 13 insertions(+), 3 deletions(-) diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c index c9095bb..54795ac 100644 --- a/src/qemu/qemu_driver.c +++ b/src/qemu/qemu_driver.c @@ -1981,10 +1981,20 @@ static int qemudDomainSaveFlag(struct qemud_driver *driver, virDomainPtr dom, if (header.compressed == QEMUD_SAVE_FORMAT_RAW) { const char *args[] = { "cat", NULL }; + /* XXX gross - why don't we reuse the fd already opened earlier */ + int fd = open(path, O_WRONLY); qemuDomainObjEnterMonitorWithDriver(driver, vm); - rc = qemuMonitorMigrateToFile(priv->mon, - QEMU_MONITOR_MIGRATE_BACKGROUND, - args, path, offset); + /* XXX needs to depend on QEMU_CAPS_MIGRATE_QEMU_FD */ + if (fd >= 0 && lseek(fd, offset, SEEK_SET) == offset) { + rc = qemuMonitorMigrateToFd(priv->mon, + QEMU_MONITOR_MIGRATE_BACKGROUND, + fd); + } else { + rc = qemuMonitorMigrateToFile(priv->mon, + QEMU_MONITOR_MIGRATE_BACKGROUND, + args, path, offset); + } + VIR_FORCE_CLOSE(fd); qemuDomainObjExitMonitorWithDriver(driver, vm); } else { const char *prog = qemudSaveCompressionTypeToString(header.compressed); -- 1.7.4