Index: head/usr.sbin/fstyp/hammer2.c
===================================================================
--- head/usr.sbin/fstyp/hammer2.c	(revision 356708)
+++ head/usr.sbin/fstyp/hammer2.c	(revision 356709)
@@ -1,152 +1,147 @@
 /*-
  * Copyright (c) 2017-2019 The DragonFly Project
  * All rights reserved.
  *
  * This software was developed by Edward Tomasz Napierala under sponsorship
  * from the FreeBSD Foundation.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
  *    documentation and/or other materials provided with the distribution.
  *
  * THIS SOFTWARE IS PROVIDED BY THE AUTHORS AND CONTRIBUTORS ``AS IS'' AND
  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE
  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  * SUCH DAMAGE.
  */
 
 #include <sys/cdefs.h>
 __FBSDID("$FreeBSD$");
 
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 #include <err.h>
 
 #include <sys/types.h>
 
 #include "hammer2_disk.h"
 
 #include "fstyp.h"
 
 static hammer2_volume_data_t*
 __read_voldata(FILE *fp)
 {
 	hammer2_volume_data_t *voldata;
 
 	voldata = read_buf(fp, 0, sizeof(*voldata));
 	if (voldata == NULL)
 		err(1, "failed to read volume data");
 
 	return (voldata);
 }
 
 static int
 __test_voldata(const hammer2_volume_data_t *voldata)
 {
 	if (voldata->magic != HAMMER2_VOLUME_ID_HBO &&
 	    voldata->magic != HAMMER2_VOLUME_ID_ABO)
 		return (1);
 
 	return (0);
 }
 
 static int
 __read_label(FILE *fp, char *label, size_t size)
 {
 	hammer2_blockref_t broot, best, *bref;
 	hammer2_media_data_t *vols[HAMMER2_NUM_VOLHDRS], *media;
 	hammer2_off_t io_off, io_base;
 	size_t bytes, io_bytes, boff;
 	int i, best_i, error = 0;
 
 	best_i = -1;
 	memset(&best, 0, sizeof(best));
 
 	for (i = 0; i < HAMMER2_NUM_VOLHDRS; i++) {
 		memset(&broot, 0, sizeof(broot));
 		broot.type = HAMMER2_BREF_TYPE_VOLUME;
 		broot.data_off = (i * HAMMER2_ZONE_BYTES64) | HAMMER2_PBUFRADIX;
 		vols[i] = read_buf(fp, broot.data_off & ~HAMMER2_OFF_MASK_RADIX,
 		    sizeof(*vols[i]));
 		broot.mirror_tid = vols[i]->voldata.mirror_tid;
 		if (best_i < 0 || best.mirror_tid < broot.mirror_tid) {
 			best_i = i;
 			best = broot;
 		}
 	}
-	if (best_i == -1) {
-		warnx("Failed to find volume header from zones");
-		error = 1;
-		goto done;
-	}
 
 	bref = &vols[best_i]->voldata.sroot_blockset.blockref[0];
 	if (bref->type != HAMMER2_BREF_TYPE_INODE) {
 		warnx("Superroot blockref type is not inode");
 		error = 2;
 		goto done;
 	}
 
 	bytes = bref->data_off & HAMMER2_OFF_MASK_RADIX;
 	if (bytes)
 		bytes = (size_t)1 << bytes;
 	if (bytes != sizeof(hammer2_inode_data_t)) {
 		warnx("Superroot blockref size does not match inode size");
 		error = 3;
 		goto done;
 	}
 
 	io_off = bref->data_off & ~HAMMER2_OFF_MASK_RADIX;
 	io_base = io_off & ~(hammer2_off_t)(HAMMER2_MINIOSIZE - 1);
 	boff = io_off - io_base;
 
 	io_bytes = HAMMER2_MINIOSIZE;
 	while (io_bytes + boff < bytes)
 		io_bytes <<= 1;
 	if (io_bytes > sizeof(*media)) {
 		warnx("Invalid I/O bytes");
 		error = 4;
 		goto done;
 	}
 
 	media = read_buf(fp, io_base, io_bytes);
 	if (boff)
 		memcpy(media, (char*)media + boff, bytes);
 
 	strlcpy(label, (char*)media->ipdata.filename, size);
 	free(media);
 done:
 	for (i = 0; i < HAMMER2_NUM_VOLHDRS; i++)
 		free(vols[i]);
 
 	return (error);
 }
 
 int
 fstyp_hammer2(FILE *fp, char *label, size_t size)
 {
 	hammer2_volume_data_t *voldata;
 	int error = 1;
 
 	voldata = __read_voldata(fp);
 	if (__test_voldata(voldata))
 		goto done;
 
 	error = __read_label(fp, label, size);
 done:
 	free(voldata);
 	return (error);
 }