samba-tool domain backup with lmdb on btrfs fails

[Jeremy Allison]

On Tue, Feb 14, 2023 at 04:39:59PM +0100, Andreas Schneider via samba-technical wrote:
>Hi,
>
>I've discovered on my Fedora 37 system that all tests related to domain backup
>fail. The strange thing is that I can't reliably reproduce it, I see reliably
>two different errors:
>
>lib/ldb/ldb_key_value/ldb_kv_search.c:162: Invalid data for index
>DN=@INDEXLIST
>
>or
>
>lib/ldb/ldb_mdb/ldb_mdb.c:419: MDB corrupted for key [ DN=@OPTIONS]
>
>ldb: Improve debug outout
>https://gitlab.com/samba-team/samba/-/merge_requests/2936
>
>It the tests worked just fine on my other system with openSUSE Tumbleweed. So
>I've tried to track it down. My home directory on openSUSE Tumbleweed is ext4
>and on Fedora 37 my home is btrfs.
>
>So I created a btrfs filesystem on Tumbleweed and could reproduce the issue.
>The next thing I did is replace the compression algorithm for the domain
>backup tarball to gzip and it also failed.
>
>Now the question is if lmdb or btrfs needs a fix and how to create a minimal
>reproducer. As I never worked on this codepath, pointers and ideas would be
>really helpful!

Andreas, can you try to reproduce on top of XFS or (possibly)
ZFS for comparison ? That might tell you if this is more of an lmdb
or a btrfs problem.