diff --git a/sbin/fsck/fsck.8 b/sbin/fsck/fsck.8
index a358007e7e58..edef23e33891 100644
--- a/sbin/fsck/fsck.8
+++ b/sbin/fsck/fsck.8
@@ -65,9 +65,9 @@ Filesystems with pass number 1 (normally just the root filesystem)
 are checked one at a time.
 When pass 1 completes, all remaining filesystems are checked,
 running one process per disk drive.
-The disk drive containing each filesystem is inferred from the longest prefix
+The disk drive containing each filesystem is inferred from the shortest prefix
 of the device name that ends in a digit; the remaining characters are assumed
-to be the partition designator.
+to be the partition and slice designator.
 .Pp
 The options are as follows:
 .Bl -tag -width indent
diff --git a/sbin/fsck/preen.c b/sbin/fsck/preen.c
index bd72d6bc9b2c..e00e84e3bbc0 100644
--- a/sbin/fsck/preen.c
+++ b/sbin/fsck/preen.c
@@ -259,12 +259,17 @@ finddisk(name)
 	size_t len = 0;
 	struct diskentry *d;
 
-	for (len = strlen(name), p = name + len - 1; p >= name; --p)
-		if (isdigit(*p)) {
-			len = p - name + 1;
-			break;
-		}
-	if (p < name)
+	p = strrchr(name, '/');
+	if (p == NULL)
+		p = name;
+	else
+		p++;
+	for (; *p && !isdigit(*p); p++)
+		continue;
+	for (; *p && isdigit(*p); p++)
+		continue;
+	len = p - name;
+	if (len == 0)
 		len = strlen(name);
 
 	TAILQ_FOREACH(d, &diskh, d_entries)