From 2c2d9c48d2daf0d78d20494c3779c0f6dc4bfa75 Mon Sep 17 00:00:00 2001
From: Nigel Croxon <ncroxon@redhat.com>
Date: Tue, 24 Sep 2019 11:39:24 -0400
Subject: [RHEL7.8 PATCH V2 37/47] mdadm: force a uuid swap on big endian

The code path for metadata 0.90 calls a common routine
fname_from_uuid that uses metadata 1.2. The code expects member
swapuuid to be setup and usable. But it is only setup when using
metadata 1.2. Since the metadata 0.90 did not create swapuuid
and set it. The test (st->ss == &super1) ? 1 : st->ss->swapuuid
fails. The swapuuid is set at compile time based on byte order.
Any call based on metadata 0.90 and on big endian processors,
the --export uuid will be incorrect.

Signed-Off-by: Nigel Croxon <ncroxon@redhat.com>
Signed-off-by: Jes Sorensen <jsorensen@fb.com>
---
 util.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/util.c b/util.c
index c26cf5f..64dd409 100644
--- a/util.c
+++ b/util.c
@@ -685,8 +685,12 @@ char *fname_from_uuid(struct supertype *st, struct mdinfo *info,
 	// work, but can't have it set if we want this printout to match
 	// all the other uuid printouts in super1.c, so we force swapuuid
 	// to 1 to make our printout match the rest of super1
+#if __BYTE_ORDER == BIG_ENDIAN
+	return __fname_from_uuid(info->uuid, 1, buf, sep);
+#else
 	return __fname_from_uuid(info->uuid, (st->ss == &super1) ? 1 :
 				 st->ss->swapuuid, buf, sep);
+#endif
 }
 
 int check_ext2(int fd, char *name)
-- 
2.7.5