[pbs-devel] [PATCH proxmox-backup 2/2] client: pxar: fix fuse mount performance for split archives

[Christian Ebner]

Adapt to the decoder method changes introduced in the pxar library,
which were introduced in order to move the consistency check for
metadata and payload data archives.

The new location of the check allows to access the pxar archive via
a `Split` variant reader instance, without penalization when just
accessing the metadata, not reading any payload data.

This greatly improves performance when accessing fuse mounted
archives.

Signed-off-by: Christian Ebner <c.ebner at proxmox.com>
---
 pbs-client/src/pxar/extract.rs | 33 ++++++++++++++++++---------------
 src/api2/tape/restore.rs       |  2 +-
 2 files changed, 19 insertions(+), 16 deletions(-)

diff --git a/pbs-client/src/pxar/extract.rs b/pbs-client/src/pxar/extract.rs
index 38d4ca89a..b3545650e 100644
--- a/pbs-client/src/pxar/extract.rs
+++ b/pbs-client/src/pxar/extract.rs
@@ -374,7 +374,10 @@ where
                 }
             }
             (true, EntryKind::File { size, .. }) => {
-                let contents = self.decoder.contents();
+                let contents = match self.decoder.contents() {
+                    Ok(contents) => contents,
+                    Err(err) => return Some(Err(err.into())),
+                };
 
                 if let Some(mut contents) = contents {
                     self.extractor.extract_file(
@@ -872,7 +875,8 @@ where
             match entry.kind() {
                 EntryKind::File { .. } => {
                     let size = decoder.content_size().unwrap_or(0);
-                    tar_add_file(&mut tarencoder, decoder.contents(), size, metadata, path).await?
+                    let contents = decoder.contents().await?;
+                    tar_add_file(&mut tarencoder, contents, size, metadata, path).await?
                 }
                 EntryKind::Hardlink(link) => {
                     if !link.data.is_empty() {
@@ -894,14 +898,9 @@ where
                                     path
                                 } else {
                                     let size = decoder.content_size().unwrap_or(0);
-                                    tar_add_file(
-                                        &mut tarencoder,
-                                        decoder.contents(),
-                                        size,
-                                        metadata,
-                                        path,
-                                    )
-                                    .await?;
+                                    let contents = decoder.contents().await?;
+                                    tar_add_file(&mut tarencoder, contents, size, metadata, path)
+                                        .await?;
                                     hardlinks.insert(realpath.to_owned(), path.to_owned());
                                     continue;
                                 }
@@ -1038,7 +1037,8 @@ where
                         metadata.stat.mode as u16,
                         true,
                     );
-                    zip.add_entry(entry, decoder.contents())
+                    let contents = decoder.contents().await?;
+                    zip.add_entry(entry, contents)
                         .await
                         .context("could not send file entry")?;
                 }
@@ -1056,7 +1056,8 @@ where
                         metadata.stat.mode as u16,
                         true,
                     );
-                    zip.add_entry(entry, decoder.contents())
+                    let contents = decoder.contents().await?;
+                    zip.add_entry(entry, contents)
                         .await
                         .context("could not send file entry")?;
                 }
@@ -1279,14 +1280,16 @@ where
                         .with_context(|| format!("error at entry {file_name_os:?}"))?;
                 }
                 EntryKind::File { size, .. } => {
+                    let mut contents = decoder
+                        .contents()
+                        .await?
+                        .context("found regular file entry without contents in archive")?;
                     extractor
                         .async_extract_file(
                             &file_name,
                             metadata,
                             *size,
-                            &mut decoder
-                                .contents()
-                                .context("found regular file entry without contents in archive")?,
+                            &mut contents,
                             extractor.overwrite_flags.contains(OverwriteFlags::FILE),
                         )
                         .await?
diff --git a/src/api2/tape/restore.rs b/src/api2/tape/restore.rs
index 382909647..2b2025f6d 100644
--- a/src/api2/tape/restore.rs
+++ b/src/api2/tape/restore.rs
@@ -1748,7 +1748,7 @@ fn try_restore_snapshot_archive<R: pxar::decoder::SeqRead>(
         }
 
         let filename = entry.file_name();
-        let mut contents = match decoder.contents() {
+        let mut contents = match decoder.contents()? {
             None => bail!("missing file content"),
             Some(contents) => contents,
         };
-- 
2.39.2