lockd: allow vgexport and vgimport

The "exported" state of the VG can be useful with lockd VGs
because the exported state keeps a VG from being used in general.
It's a way to keep a VG protected and out of the way.

Also fix the command flags: ALL_VGS_IS_DEFAULT is not true for
vgimport/vgexport, since they both return errors immediately if
no VG args are specified.  LOCKD_VG_SH is not true for vgexport
beause it must use an ex lock to write the VG.

tools/commands.h

@@ -1191,7 +1191,7 @@ xx(vgdisplay,
 
 xx(vgexport,
    "Unregister volume group(s) from the system",
-   ALL_VGS_IS_DEFAULT | LOCKD_VG_SH,
+   0,
    "vgexport\n"
    "\t[-a|--all]\n"
    "\t[--commandprofile ProfileName]\n"
@@ -1229,7 +1229,7 @@ xx(vgextend,
 
 xx(vgimport,
    "Register exported volume group with system",
-   ALL_VGS_IS_DEFAULT,
+   0,
    "vgimport\n"
    "\t[-a|--all]\n"
    "\t[--commandprofile ProfileName]\n"

tools/vgchange.c

@@ -888,7 +888,8 @@ static int vgchange_single(struct cmd_context *cmd, const char *vg_name,
 		{ systemid_ARG, &_vgchange_system_id },
 	};
 
-	if (vg_is_exported(vg)) {
+	if (vg_is_exported(vg) &&
+	    !(arg_is_set(cmd, lockstop_ARG) || arg_is_set(cmd, lockstart_ARG))) {
 		log_error("Volume group \"%s\" is exported", vg_name);
 		return ECMD_FAILED;
 	}
@@ -1052,6 +1053,7 @@ static int _lockd_vgchange(struct cmd_context *cmd, int argc, char **argv)
 
 int vgchange(struct cmd_context *cmd, int argc, char **argv)
 {
+	uint32_t flags = 0;
 	int ret;
 
 	int noupdate =
@@ -1185,8 +1187,12 @@ int vgchange(struct cmd_context *cmd, int argc, char **argv)
 	if (!_lockd_vgchange(cmd, argc, argv))
 		return_ECMD_FAILED;
 
-	ret = process_each_vg(cmd, argc, argv, update ? READ_FOR_UPDATE : 0,
+	if (update)
-			      NULL, &vgchange_single);
+		flags |= READ_FOR_UPDATE;
+	if (arg_is_set(cmd, lockstart_ARG) || arg_is_set(cmd, lockstop_ARG))
+		flags |= READ_ALLOW_EXPORTED;
+
+	ret = process_each_vg(cmd, argc, argv, flags, NULL, &vgchange_single);
 
 	/* Wait for lock-start ops that were initiated in vgchange_lockstart. */
 

tools/vgexport.c

@@ -22,19 +22,30 @@ static int vgexport_single(struct cmd_context *cmd __attribute__((unused)),
 {
 	struct pv_list *pvl;
 
-	/* vgexport/vgimport have to use with shared VGs. */
-	if (is_lockd_type(vg->lock_type)) {
-		log_error("Volume group \"%s\" has lock_type %s that cannot be exported",
-			  vg_name, vg->lock_type);
-		goto bad;
-	}
-
 	if (lvs_in_vg_activated(vg)) {
 		log_error("Volume group \"%s\" has active logical volumes",
 			  vg_name);
 		goto bad;
 	}
 
+	if (is_lockd_type(vg->lock_type)) {
+		struct lv_list *lvl;
+		dm_list_iterate_items(lvl, &vg->lvs) {
+			if (!lockd_lv_uses_lock(lvl->lv))
+				continue;
+
+			if (!lockd_lv(cmd, lvl->lv, "ex", 0)) {
+				log_error("LV %s/%s must be inactive on all hosts before vgexport.",
+					  vg->name, display_lvname(lvl->lv));
+				goto bad;
+			}
+
+			if (!lockd_lv(cmd, lvl->lv, "un", 0))
+				goto bad;
+		}
+	}
+
+
 	if (!archive(vg))
 		goto_bad;
 

tools/vgimport.c

@@ -37,6 +37,8 @@ static int vgimport_single(struct cmd_context *cmd,
 		goto_bad;
 
 	vg->status &= ~EXPORTED_VG;
+
+	if (!is_lockd_type(vg->lock_type))
 		vg->system_id = cmd->system_id ? dm_pool_strdup(vg->vgmem, cmd->system_id) : NULL;
 
 	dm_list_iterate_items(pvl, &vg->pvs) {