Some file lost when send back snapshot.

[MASAKI Haruka <reasonset@inflaton.co.jp>]

I send snapshot from backup volume, and send new snaopshot to backup volume,
and some file lost in received volume.

In detail:

1. Host A has new Btrfs volume and Host B have two backuped readonly subvolumes (190312-010100, 190315-001000).
2. Host B send 190315-001000 subvolume to Host A.
3. Host A completely received (all files exist.)
4. Host B took new readonly snapshot "back1" on 190315-001000 (all files exist.)
5. Host B send back1 with `-p 190315-001000` to Host A (some file lost.)
6. Host B took new read-writable snapshot "world" on back1 (all files exist.)
7. Host B modified world.
8. Host B took new readonly snapshot "back2" on world (all files exist.)
9. Host B send back2 with `-p 190315-001000` to Host A (some file lost.)
10. Deleted received snapshot and Host B send back2 with `-p back1` to Host A (some file lost.)

Kernel
5.0.5-1-MANJARO

Btrfs progs
btrfs-progs 4.20.2-1


What I should do?

Thanks.



Masaki Haruka