Commit db886e4d authored by Alex Ng's avatar Alex Ng Committed by Greg Kroah-Hartman
Browse files

Drivers: hv: utils: Check VSS daemon is listening before a hot backup 



Hyper-V host will send a VSS_OP_HOT_BACKUP request to check if guest is
ready for a live backup/snapshot. The driver should respond to the check
only if the daemon is running and listening to requests. This allows the
host to fallback to standard snapshots in case the VSS daemon is not
running.

Signed-off-by: default avatarAlex Ng <alexng@messages.microsoft.com>
Signed-off-by: default avatarK. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 497af84b

drivers/hv/hv_snapshot.c

+6 −3
Original line number Diff line number Diff line
@@ -142,6 +142,11 @@ static int vss_on_msg(void *msg, int len) 
		return vss_handle_handshake(vss_msg);

	} else if (vss_transaction.state == HVUTIL_USERSPACE_REQ) {

		vss_transaction.state = HVUTIL_USERSPACE_RECV;



		if (vss_msg->vss_hdr.operation == VSS_OP_HOT_BACKUP)

			vss_transaction.msg->vss_cf.flags =

				VSS_HBU_NO_AUTO_RECOVERY;



		if (cancel_delayed_work_sync(&vss_timeout_work)) {

			vss_respond_to_host(vss_msg->error);

			/* Transaction is finished, reset the state. */
@@ -202,6 +207,7 @@ static void vss_handle_request(struct work_struct *dummy) 
	 */

	case VSS_OP_THAW:

	case VSS_OP_FREEZE:

	case VSS_OP_HOT_BACKUP:

		if (vss_transaction.state < HVUTIL_READY) {

			/* Userspace is not registered yet */

			vss_respond_to_host(HV_E_FAIL);
@@ -210,9 +216,6 @@ static void vss_handle_request(struct work_struct *dummy) 
		vss_transaction.state = HVUTIL_HOSTMSG_RECEIVED;

		vss_send_op();

		return;

	case VSS_OP_HOT_BACKUP:

		vss_transaction.msg->vss_cf.flags = VSS_HBU_NO_AUTO_RECOVERY;

		break;

	case VSS_OP_GET_DM_INFO:

		vss_transaction.msg->dm_info.flags = 0;

		break;

tools/hv/hv_vss_daemon.c

+3 −0
Original line number Diff line number Diff line
@@ -250,6 +250,9 @@ int main(int argc, char *argv[]) 
				syslog(LOG_ERR, "/etc/fstab and /proc/mounts");

			}

			break;

		case VSS_OP_HOT_BACKUP:

			syslog(LOG_INFO, "VSS: op=CHECK HOT BACKUP\n");

			break;

		default:

			syslog(LOG_ERR, "Illegal op:%d\n", op);

		}

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