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: Alex Ng <alexng@messages.microsoft.com>
Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/hv/hv_snapshot.c b/drivers/hv/hv_snapshot.c
index c4013c859bcd905c5bef56d469fd13a482af6ab8..a6707133c297c7a1435b1bdcda446256671fc080 100644 (file)
--- a/drivers/hv/hv_snapshot.c
+++ b/drivers/hv/hv_snapshot.c
@@ -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;

diff --git a/tools/hv/hv_vss_daemon.c b/tools/hv/hv_vss_daemon.c
index 5d51d6ff08e6a603173ad071b7651cc0fbce241d..e0829809c897064554ca4ad342e4dd22c6c1c024 100644 (file)
--- a/tools/hv/hv_vss_daemon.c
+++ b/tools/hv/hv_vss_daemon.c
@@ -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);
                }