Re: [PATCH v1 proxmox-backup 2/3] client: pxar: consistently ignore vanished files and warn about them

[Robert Obkircher <r.obkircher@proxmox.com>]

On 07.05.26 10:36, Christian Ebner wrote:
> Two nits inline, otherwise LGTM.
>
> Reviewed-by: Christian Ebner <c.ebner@proxmox.com>
>
> On 5/6/26 1:48 PM, Robert Obkircher wrote:
>> Combine the error paths and treat deleted entries equally in both
>> cases. Since this used to be a hard error in some cases, it also makes
>> sense to emit a warning about it.
>>
>> Signed-off-by: Robert Obkircher <r.obkircher@proxmox.com>
>> ---
>>   pbs-client/src/pxar/create.rs | 32 ++++++++++++--------------------
>>   1 file changed, 12 insertions(+), 20 deletions(-)
>>
>> diff --git a/pbs-client/src/pxar/create.rs
>> b/pbs-client/src/pxar/create.rs
>> index 08c5c9b44..47cbf50a8 100644
>> --- a/pbs-client/src/pxar/create.rs
>> +++ b/pbs-client/src/pxar/create.rs
>> @@ -695,36 +695,28 @@ impl Archiver {
>>                       })
>>                   });
>>   -            match match_result {
>> +            let stat_result = match match_result {
>>                   Ok(Some(MatchType::Exclude)) => {
>>                       debug!("matched by exclude pattern
>> '{full_path:?}'");
>>                       continue;
>>                   }
>> -                Ok(_) => (),
>> -                Err(err) if err.not_found() => continue,
>> +                Ok(_) => stat_result.map_or_else(do_stat, Ok),
>> +                Err(e) => Err(e),
>> +            };
>> +
>> +            let stat = match stat_result {
>> +                Ok(stat) => stat,
>> +                Err(err) if err.not_found() => {
>> +                    warn!("warning: file vanished while reading
>> directory: {full_path:?}");
>
> nit: should use and slightly adapt the report_vanished_file() helper. 
Imo the messages should be different, so this would essentially turn into:

fn report_vanished_file(message: &str, path: &Path) {
    warn!("warning: file vanished {message}: {path:?}")
}

which seemed overly complicated for something that would only be
called from two locations.

I also noticed that `read_pxar_excludes` calls `open_file` without
setting `self.path`, so the existing helpers would print the wrong
message in that case.

>
>> +                    continue;
>> +                }
>>                   Err(Errno::ESTALE) => {
>>                       self.report_stale_file_handle(Some(&full_path));
>>                       continue;
>>                   }
>>                   Err(err) => {
>> -                    return Err(err).with_context(|| format!("stat
>> failed on {full_path:?}"))
>> +                    return
>> Err(Error::from(err).context(format!("stat failed on {full_path:?}")))
>
> nit: please use with_context() over context() here, since the former
> is evaluated lazily only once an error does occur [0].
>
> [0]
> https://docs.rs/anyhow/latest/anyhow/trait.Context.html#required-methods 
How? This is the error path that converts the Errno to an anyhow
error. It doesn't call the method from that trait.
>
>>                   }
>> -            }
>> -
>> -            let stat = match stat_result {
>> -                Some(stat) => stat,
>> -                None => match do_stat() {
>> -                    Ok(stat) => stat,
>> -                    Err(Errno::ESTALE) => {
>> -                       
>> self.report_stale_file_handle(Some(&full_path));
>> -                        continue;
>> -                    }
>> -                    Err(err) => {
>> -                        return Err(
>> -                            Error::from(err).context(format!("stat
>> failed on {full_path:?}"))
>> -                        )
>> -                    }
>> -                },
>>               };
>>                 self.entry_counter += 1;
>