From bdc4f1e2b47aaff19ad8588e0513a10c30f3cc4e Mon Sep 17 00:00:00 2001
From: "Yan, Zheng" <zyan@redhat.com>
Date: Thu, 7 Nov 2019 16:15:07 +0800
Subject: [PATCH] mds: tolerate no snaprealm encoded in on-disk root inode

Signed-off-by: "Yan, Zheng" <zyan@redhat.com>
Fixes: https://tracker.ceph.com/issues/42675
(cherry picked from commit 141eddba068dd2dc5afe783c21b4af751306d281)
---
 src/mds/CInode.cc | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/src/mds/CInode.cc b/src/mds/CInode.cc
index 6c8084bb0a4d7..3209763b7b075 100644
--- a/src/mds/CInode.cc
+++ b/src/mds/CInode.cc
@@ -2817,7 +2817,8 @@ void CInode::decode_snap_blob(const bufferlist& snapbl)
       }
     }
     dout(20) << __func__ << " " << *snaprealm << dendl;
-  } else if (snaprealm) {
+  } else if (snaprealm &&
+	     !is_root() && !is_mdsdir()) { // see https://tracker.ceph.com/issues/42675
     ceph_assert(mdcache->mds->is_any_replay());
     snaprealm->merge_to(NULL);
   }
-- 
2.47.3