bectl(8): Take origin snapshot into account when calculating used space

This more closely matches the behavior for beadm. The associated libbe(3)
API is still getting worked out a little bit.

lib/libbe/be.h

@@ -67,6 +67,7 @@ const char *be_nextboot_path(libbe_handle_t *);
 const char *be_root_path(libbe_handle_t *);
 
 int be_get_bootenv_props(libbe_handle_t *, nvlist_t *);
+int be_get_snapshot_props(libbe_handle_t *, const char *, nvlist_t *);
 int be_prop_list_alloc(nvlist_t **be_list);
 void be_prop_list_free(nvlist_t *be_list);
 

lib/libbe/be_access.c

@@ -83,6 +83,7 @@ be_mounted_at(libbe_handle_t *lbh, const char *path, nvlist_t *details)
 
 			propinfo.lbh = lbh;
 			propinfo.list = details;
+			propinfo.single_object = false;
 			prop_list_builder_cb(root_hdl, &propinfo);
 			zfs_close(root_hdl);
 		}

lib/libbe/be_impl.h

@@ -58,6 +58,7 @@ struct libbe_dccb {
 typedef struct prop_data {
 	nvlist_t *list;
 	libbe_handle_t *lbh;
+	bool single_object;	/* list will contain props directly */
 } prop_data_t;
 
 int prop_list_builder_cb(zfs_handle_t *, void *);

lib/libbe/be_info.c

@@ -94,9 +94,28 @@ be_get_bootenv_props(libbe_handle_t *lbh, nvlist_t *dsnvl)
 
 	data.lbh = lbh;
 	data.list = dsnvl;
+	data.single_object = false;
 	return (prop_list_builder(&data));
 }
 
+int
+be_get_snapshot_props(libbe_handle_t *lbh, const char *name, nvlist_t *props)
+{
+	zfs_handle_t *snap_hdl;
+	prop_data_t data;
+	int ret;
+
+	data.lbh = lbh;
+	data.list = props;
+	data.single_object = true;
+	if ((snap_hdl = zfs_open(lbh->lzh, name,
+	    ZFS_TYPE_SNAPSHOT)) == NULL)
+		return (BE_ERR_ZFSOPEN);
+
+	ret = prop_list_builder_cb(snap_hdl, &data);
+	zfs_close(snap_hdl);
+	return (ret);
+}
 
 /*
  * Internal callback function used by zfs_iter_filesystems. For each dataset in
@@ -121,7 +140,10 @@ prop_list_builder_cb(zfs_handle_t *zfs_hdl, void *data_p)
 	data = (prop_data_t *)data_p;
 	lbh = data->lbh;
 
-	nvlist_alloc(&props, NV_UNIQUE_NAME, KM_SLEEP);
+	if (data->single_object)
+		props = data->list;
+	else
+		nvlist_alloc(&props, NV_UNIQUE_NAME, KM_SLEEP);
 
 	dataset = zfs_get_name(zfs_hdl);
 	nvlist_add_string(props, "dataset", dataset);
@@ -169,7 +191,8 @@ prop_list_builder_cb(zfs_handle_t *zfs_hdl, void *data_p)
 	nvlist_add_boolean_value(props, "nextboot",
 	    (strcmp(be_nextboot_path(lbh), dataset) == 0));
 
-	nvlist_add_nvlist(data->list, name, props);
+	if (!data->single_object)
+		nvlist_add_nvlist(data->list, name, props);
 
 	return (0);
 }

lib/libbe/libbe.3

@@ -138,6 +138,9 @@ of state to be retained, such as errors from previous operations.
 .Ft int
 .Fn be_get_bootenv_props "libbe_handle_t *, nvlist_t *" ;
 .Pp
+.Ft int
+.Fn be_get_snapshot_props "libbe_handle_t *, const char *, nvlist_t *" ;
+.Pp
 .Ft void
 .Fn be_prop_list_free "nvlist_t *" ;
 .\" .Ft void

sbin/bectl/bectl.c

@@ -424,11 +424,12 @@ print_dataset(nvpair_t *cur, struct printc *pc)
 #define	BUFSZ	64
 	char buf[BUFSZ];
 	unsigned long long ctimenum, space;
-	nvlist_t *dsprops;
+	nvlist_t *dsprops, *originprops;
 	char *propstr;
 	int active_colsz;
 	boolean_t active_now, active_reboot;
 
+	originprops = NULL;
 	propstr = nvpair_name(cur);
 	/* XXX TODO: Some views show snapshots */
 	if (strchr(propstr, '@') != NULL)
@@ -457,9 +458,27 @@ print_dataset(nvpair_t *cur, struct printc *pc)
 	else
 		printf("%*s ", pc->mount_colsz, "-");
 
+	if (nvlist_lookup_string(dsprops, "origin", &propstr) == 0) {
+		if (be_prop_list_alloc(&originprops) != 0) {
+			fprintf(stderr,
+			    "bectl list: failed to allocate origin prop nvlist\n");
+			return;
+		}
+		if (be_get_snapshot_props(be, propstr, originprops) != 0) {
+			/* XXX TODO: Real errors */
+			fprintf(stderr,
+			    "bectl list: failed to fetch origin properties\n");
+			return;
+		}
+	}
+
 	if (nvlist_lookup_string(dsprops, "used", &propstr) == 0) {
 		space = strtoull(propstr, NULL, 10);
 
+		if (originprops != NULL && nvlist_lookup_string(originprops,
+		    "used", &propstr) == 0)
+			space += strtoull(propstr, NULL, 10);
+
 		/* Alas, there's more to it,. */
 		humanize_number(buf, 6, space, "", HN_AUTOSCALE,
 			HN_DECIMAL | HN_NOSPACE | HN_B);
@@ -475,6 +494,8 @@ print_dataset(nvpair_t *cur, struct printc *pc)
 	}
 
 	printf("\n");
+	if (originprops != NULL)
+		be_prop_list_free(originprops);
 #undef BUFSZ
 }