[pbs-devel] [PATCH proxmox-backup v2 3/8] chunk store: invert chunk filename checks in chunk store iterator

[Fabian Grünbichler]

On December 11, 2025 4:38 pm, Christian Ebner wrote:
> Optimizes the chunk filename check towards regular chunk files by
> explicitley checking for the correct length.
> 
> While the check for ascii hexdigits needs to be stated twice, this
> avoids to check for the `.bad` extension if the chunk filename did
> already match the expected length.

I don't get this part, we could still check first and only once that the
first 64 bytes are valid hex?

if bytes.len() < 64 {
  continue;
}

if !bytes.iter().take(64).all(u8::is_ascii_hexdigit) {
  continue;
}

// now start looking at the length + potential extension

> 
> This will also help to better distinguish bad chunks and chunks
> used markers for s3 datastores in subsequent changes.
> 
> Signed-off-by: Christian Ebner <c.ebner at proxmox.com>
> ---
>  pbs-datastore/src/chunk_store.rs | 17 +++++++++++------
>  1 file changed, 11 insertions(+), 6 deletions(-)
> 
> diff --git a/pbs-datastore/src/chunk_store.rs b/pbs-datastore/src/chunk_store.rs
> index a5e5f6261..7980938ad 100644
> --- a/pbs-datastore/src/chunk_store.rs
> +++ b/pbs-datastore/src/chunk_store.rs
> @@ -315,15 +315,20 @@ impl ChunkStore {
>                          Some(Ok(entry)) => {
>                              // skip files if they're not a hash
>                              let bytes = entry.file_name().to_bytes();
> -                            if bytes.len() != 64 && bytes.len() != 64 + ".0.bad".len() {
> -                                continue;
> +
> +                            if bytes.len() == 64 && bytes.iter().take(64).all(u8::is_ascii_hexdigit)
> +                            {
> +                                return Some((Ok(entry), percentage, false));
>                              }
> -                            if !bytes.iter().take(64).all(u8::is_ascii_hexdigit) {
> -                                continue;
> +
> +                            if bytes.len() == 64 + ".0.bad".len()
> +                                && bytes.iter().take(64).all(u8::is_ascii_hexdigit)
> +                            {
> +                                let bad = bytes.ends_with(b".bad");
> +                                return Some((Ok(entry), percentage, bad));

while this mimics the old code, it is still broken (a chunk digest +
.fooba or any other 6-byte suffix that is not "??.bad" is returned as
non-bad chunk, since the length matches a bad chunk, but the extension
does not).

>                              }
>  
> -                            let bad = bytes.ends_with(b".bad");
> -                            return Some((Ok(entry), percentage, bad));
> +                            continue;
>                          }
>                          Some(Err(err)) => {
>                              // stop after first error
> -- 
> 2.47.3
> 
> 
> 
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> 
>