[pbs-devel] [PATCH proxmox-backup v2] GC: chunk store: fix chunk using markers cleanup

[Thomas Lamprecht]

Am 25.11.25 um 15:18 schrieb Fabian Grünbichler:
>> +                if filename
>> +                    .to_bytes()
>> +                    .ends_with(USING_MARKER_FILENAME_EXT.as_bytes())
>> +                {
>> +                    unlinkat(Some(dirfd), filename, UnlinkatFlags::NoRemoveDir).map_err(|err| {
>> +                        format_err!("unlinking chunk using marker {filename:?} failed - {err}")
>> +                    })?;
>> +                    drop(lock);
>> +                    continue;
>> +                }
> this looks okay as a stop-gap, but isn't the actual problem that
> 
> .using
> 
> and
> 
> .0.bad
> 
> have the same length, so we end up taking a codepath using a weird "bad
> but not bad" filename instead of skipping those markers in phase3?

I mean, yes, but these .using markers would need to be cleaned (or updated to
ensure they match reality) sooner or later anyway, or does that already happen
elsewhere?

> 
> in get_chunk_iterator, we skip all files that are not 64 bytes or
> 64+len(.0.bad) bytes long, but then set the "bad" flag based on the
> extension..
> 
> and then in cond_sweep_chunk in sweep_unused_chunk, we convert non-bad
> chunk filenames to digests which then fails for the "using" filenames,
> because they are too long (per the error from the forum thread).

I mean, "using" is also not that of a telling suffix, "referenced" or
"remote" or the like might be better, even just "used" is slightly easier
to grasp for me.