[pbs-devel] [PATCH v3 proxmox-backup 37/58] client: pxar: helper for lookup of reusable dynamic entries

[Fabian Grünbichler]

Quoting Christian Ebner (2024-03-28 13:36:46)
> The helper method allows to lookup the entries of a dynamic index
> which fully cover a given offset range. Further, the helper returns
> the start padding from the start offset of the dynamic index entry
> to the start offset of the given range and the end padding.
> 
> This will be used to lookup size and digest for chunks covering the
> payload range of a regular file in order to re-use found chunks by
> indexing them in the archives index file instead of re-encoding the
> payload.
> 
> Signed-off-by: Christian Ebner <c.ebner at proxmox.com>
> ---
> changes since version 2:
> - moved this from the dynamic index to the pxar create as suggested
> - refactored and optimized search, going for linear search to find the
>   end entry
> - reworded commit message
> 
>  pbs-client/src/pxar/create.rs | 63 +++++++++++++++++++++++++++++++++++
>  1 file changed, 63 insertions(+)
> 
> diff --git a/pbs-client/src/pxar/create.rs b/pbs-client/src/pxar/create.rs
> index 2bb5a6253..e2d3954ca 100644
> --- a/pbs-client/src/pxar/create.rs
> +++ b/pbs-client/src/pxar/create.rs
> @@ -2,6 +2,7 @@ use std::collections::{HashMap, HashSet};
>  use std::ffi::{CStr, CString, OsStr};
>  use std::fmt;
>  use std::io::{self, Read};
> +use std::ops::Range;
>  use std::os::unix::ffi::OsStrExt;
>  use std::os::unix::io::{AsRawFd, FromRawFd, IntoRawFd, OwnedFd, RawFd};
>  use std::path::{Path, PathBuf};
> @@ -16,6 +17,7 @@ use nix::fcntl::OFlag;
>  use nix::sys::stat::{FileStat, Mode};
>  
>  use pathpatterns::{MatchEntry, MatchFlag, MatchList, MatchType, PatternFlag};
> +use pbs_datastore::index::IndexFile;
>  use proxmox_sys::error::SysError;
>  use pxar::encoder::{LinkOffset, SeqWrite};
>  use pxar::Metadata;
> @@ -25,6 +27,7 @@ use proxmox_lang::c_str;
>  use proxmox_sys::fs::{self, acl, xattr};
>  
>  use pbs_datastore::catalog::BackupCatalogWriter;
> +use pbs_datastore::dynamic_index::DynamicIndexReader;
>  
>  use crate::pxar::metadata::errno_is_unsupported;
>  use crate::pxar::tools::assert_single_path_component;
> @@ -791,6 +794,66 @@ impl Archiver {
>      }
>  }
>  
> +/// Dynamic Entry reusable by payload references
> +#[derive(Clone, Debug)]
> +#[repr(C)]
> +pub struct ReusableDynamicEntry {
> +    size_le: u64,

I don't think the `le` here makes sense, this is never stored on disk..

> +    digest: [u8; 32],
> +}