zed: Find devid and pool_guid through vdev_guid

For L2ARC VDEVs, the devid might be missing on removal event
since its not part of the blkid cache and L2ARC VDEV does not
contain pool guid in its blkid. Added support to find devid
and pool_guid from vdev_guid if available.

Signed-off-by: Ameer Hamza <ahamza@ixsystems.com>

cmd/zed/agents/zfs_agents.c

@@ -80,6 +80,7 @@ zfs_agent_iter_vdev(zpool_handle_t *zhp, nvlist_t *nvl, void *arg)
 	char *path = NULL;
 	uint_t c, children;
 	nvlist_t **child;
+	uint64_t vdev_guid;
 
 	/*
 	 * First iterate over any children.
@@ -100,7 +101,7 @@ zfs_agent_iter_vdev(zpool_handle_t *zhp, nvlist_t *nvl, void *arg)
 	    &child, &children) == 0) {
 		for (c = 0; c < children; c++) {
 			if (zfs_agent_iter_vdev(zhp, child[c], gsp)) {
-				gsp->gs_vdev_type = DEVICE_TYPE_L2ARC;
+				gsp->gs_vdev_type = DEVICE_TYPE_SPARE;
 				return (B_TRUE);
 			}
 		}
@@ -109,7 +110,7 @@ zfs_agent_iter_vdev(zpool_handle_t *zhp, nvlist_t *nvl, void *arg)
 	    &child, &children) == 0) {
 		for (c = 0; c < children; c++) {
 			if (zfs_agent_iter_vdev(zhp, child[c], gsp)) {
-				gsp->gs_vdev_type = DEVICE_TYPE_SPARE;
+				gsp->gs_vdev_type = DEVICE_TYPE_L2ARC;
 				return (B_TRUE);
 			}
 		}
@@ -126,6 +127,21 @@ zfs_agent_iter_vdev(zpool_handle_t *zhp, nvlist_t *nvl, void *arg)
 		    &gsp->gs_vdev_expandtime);
 		return (B_TRUE);
 	}
+	/*
+	 * Otherwise, on a vdev guid match, grab the devid and expansion
+	 * time. The devid might be missing on removal since its not part
+	 * of blkid cache and L2ARC VDEV does not contain pool guid in its
+	 * blkid, so this is a special case for L2ARC VDEV.
+	 */
+	else if (gsp->gs_vdev_guid != 0 && gsp->gs_devid == NULL &&
+	    nvlist_lookup_uint64(nvl, ZPOOL_CONFIG_GUID, &vdev_guid) == 0 &&
+	    gsp->gs_vdev_guid == vdev_guid) {
+		(void) nvlist_lookup_string(nvl, ZPOOL_CONFIG_DEVID,
+		    &gsp->gs_devid);
+		(void) nvlist_lookup_uint64(nvl, ZPOOL_CONFIG_EXPANSION_TIME,
+		    &gsp->gs_vdev_expandtime);
+		return (B_TRUE);
+	}
 
 	return (B_FALSE);
 }
@@ -148,7 +164,7 @@ zfs_agent_iter_pool(zpool_handle_t *zhp, void *arg)
 	/*
 	 * if a match was found then grab the pool guid
 	 */
-	if (gsp->gs_vdev_guid) {
+	if (gsp->gs_vdev_guid && gsp->gs_devid) {
 		(void) nvlist_lookup_uint64(config, ZPOOL_CONFIG_POOL_GUID,
 		    &gsp->gs_pool_guid);
 	}
@@ -208,11 +224,28 @@ zfs_agent_post_event(const char *class, const char *subclass, nvlist_t *nvl)
 		tod[1] = tv.tv_usec;
 		(void) nvlist_add_int64_array(payload, FM_EREPORT_TIME, tod, 2);
 
+		/*
+		 * If devid is missing but vdev_guid is available, find devid
+		 * and pool_guid from vdev_guid.
+		 */
+		if (nvlist_lookup_string(nvl, DEV_IDENTIFIER,
+		    &search.gs_devid) != 0 && vdev_guid != 0 &&
+		    pool_guid == 0) {
+			search.gs_vdev_guid = vdev_guid;
+			zpool_iter(g_zfs_hdl, zfs_agent_iter_pool, &search);
+			if (search.gs_devid != NULL) {
+				nvlist_add_string(nvl, DEV_IDENTIFIER,
+				    search.gs_devid);
+			}
+			if (search.gs_pool_guid != 0)
+				pool_guid = search.gs_pool_guid;
+			devtype = search.gs_vdev_type;
+		}
 		/*
 		 * For multipath, spare and l2arc devices ZFS_EV_VDEV_GUID or
 		 * ZFS_EV_POOL_GUID may be missing so find them.
 		 */
-		if (pool_guid == 0 || vdev_guid == 0) {
+		else if (pool_guid == 0 || vdev_guid == 0) {
 			if ((nvlist_lookup_string(nvl, DEV_IDENTIFIER,
 			    &search.gs_devid) == 0) &&
 			    (zpool_iter(g_zfs_hdl, zfs_agent_iter_pool, &search)