activate: add autoactivation hooks

Define an 'activation_handler' that gets called automatically on
PV appearance/disappearance while processing the lvmetad_pv_found
and lvmetad_pv_gone functions that are supposed to update the
lvmetad state based on PV availability state. For now, the actual
support is for PV appearance only, leaving room for PV disappearance
support as well (which is a more complex problem to solve as this
needs to count with possible device stack).

Add a new activation change mode - CHANGE_AAY exposed as
'--activate ay/-aay' argument ('activate automatically').

Factor out the vgchange activation functionality for use in other
tools (like pvscan...).

1 files changed, 31 insertions, 8 deletions

diff --git a/lib/cache/lvmetad.c b/lib/cache/lvmetad.c
index d70e4905..6ef30db1 100644
--- a/lib/cache/lvmetad.c
+++ b/lib/cache/lvmetad.c
@@ -322,7 +322,7 @@ int lvmetad_vg_update(struct volume_group *vg)
 		/* NB. the PV fmt pointer is sometimes wrong during vgconvert */
 		if (pvl->pv->dev && !lvmetad_pv_found(pvl->pv->id, pvl->pv->dev,
 						      vg->fid ? vg->fid->fmt : pvl->pv->fmt,
-						      pvl->pv->label_sector, NULL))
+						      pvl->pv->label_sector, NULL, NULL))
 			return 0;
 	}
 
@@ -536,7 +536,7 @@ static const char *_print_mdas(struct lvmcache_info *info)
 }
 
 int lvmetad_pv_found(struct id pvid, struct device *device, const struct format_type *fmt,
-		     uint64_t label_sector, struct volume_group *vg)
+		     uint64_t label_sector, struct volume_group *vg, activation_handler handler)
 {
 	char uuid[64];
 	daemon_reply reply;
@@ -544,6 +544,7 @@ int lvmetad_pv_found(struct id pvid, struct device *device, const struct format_
 	const char *mdas = NULL;
 	char *pvmeta;
 	char *buf = NULL;
+	const char *status;
 	int result;
 
 	if (!_using_lvmetad)
@@ -603,12 +604,26 @@ int lvmetad_pv_found(struct id pvid, struct device *device, const struct format_
 	dm_free(pvmeta);
 
 	result = _lvmetad_handle_reply(reply, "update PV", uuid, NULL);
+
+	if (result && handler) {
+		status = daemon_reply_str(reply, "status", "<missing>");
+		if (!strcmp(status, "partial"))
+			handler(vg, 1, CHANGE_AAY);
+		else if (!strcmp(status, "complete"))
+			handler(vg, 0, CHANGE_AAY);
+		else if (!strcmp(status, "orphan"))
+			;
+		else
+			log_error("Request to %s %s in lvmetad gave status %s.",
+			  "update PV", uuid, status);
+	}
+
 	daemon_reply_destroy(reply);
 
 	return result;
 }
 
-int lvmetad_pv_gone(dev_t device, const char *pv_name)
+int lvmetad_pv_gone(dev_t device, const char *pv_name, activation_handler handler)
 {
 	daemon_reply reply;
 	int result;
@@ -617,6 +632,13 @@ int lvmetad_pv_gone(dev_t device, const char *pv_name)
 	if (!_using_lvmetad)
 		return 1;
 
+	/*
+         *  TODO: automatic volume deactivation takes place here *before*
+         *        all cached info is gone - call handler. Also, consider
+         *        integrating existing deactivation script  that deactivates
+         *        the whole stack from top to bottom (not yet upstream).
+         */
+
 	reply = daemon_send_simple(_lvmetad, "pv_gone", "device = %d", device, NULL);
 
 	result = _lvmetad_handle_reply(reply, "drop PV", pv_name, &found);
@@ -627,9 +649,9 @@ int lvmetad_pv_gone(dev_t device, const char *pv_name)
 	return result;
 }
 
-int lvmetad_pv_gone_by_dev(struct device *dev)
+int lvmetad_pv_gone_by_dev(struct device *dev, activation_handler handler)
 {
-	return lvmetad_pv_gone(dev->dev, dev_name(dev));
+	return lvmetad_pv_gone(dev->dev, dev_name(dev), handler);
 }
 
 int lvmetad_active(void)
@@ -665,7 +687,8 @@ static int _pvscan_lvmetad_single(struct metadata_area *mda, void *baton)
 	return 1;
 }
 
-int pvscan_lvmetad_single(struct cmd_context *cmd, struct device *dev)
+int pvscan_lvmetad_single(struct cmd_context *cmd, struct device *dev,
+			  activation_handler handler)
 {
 	struct label *label;
 	struct lvmcache_info *info;
@@ -680,7 +703,7 @@ int pvscan_lvmetad_single(struct cmd_context *cmd, struct device *dev)
 
 	if (!label_read(dev, &label, 0)) {
 		log_print("No PV label found on %s.", dev_name(dev));
-		if (!lvmetad_pv_gone_by_dev(dev))
+		if (!lvmetad_pv_gone_by_dev(dev, handler))
 			goto_bad;
 		return 1;
 	}
@@ -704,7 +727,7 @@ int pvscan_lvmetad_single(struct cmd_context *cmd, struct device *dev)
 	 * sync needs to be killed.
 	 */
 	if (!lvmetad_pv_found(*(struct id *)dev->pvid, dev, lvmcache_fmt(info),
-			      label->sector, baton.vg)) {
+			      label->sector, baton.vg, handler)) {
 		release_vg(baton.vg);
 		goto_bad;
 	}