refcount: dangling data blocks

[iwanbk]

steps:

#mc put Cargo.toml cas/semua
...-cas/Cargo.toml: 1.24 KiB / 1.24 KiB  ▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓  94.45 KiB/s 0s
#mc put Cargo.toml cas/semua
...-cas/Cargo.toml: 1.24 KiB / 1.24 KiB  ▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓  94.45 KiB/s 0s
#mc rm cas/semua/Cargo.toml
Removed `cas/semua/Cargo.toml`.
#mc rm cas/semua/Cargo.toml
mc: <ERROR> Failed to remove `cas/semua/Cargo.toml`. Object does not exist

what happens

Second rm is failed, but the data block still exists under the fs-root.

Expectation

either the second rm succeed or the data block removed at first rm

suspect:

s3-cas/src/cas/fs.rs

Line 201 in 6117413

bucket.remove(object)?;

doing remove too early