[pbs-devel] [RFC proxmox-backup 18/36] client: mount: make split pxar archives mountable

[Christian Ebner <c.ebner@proxmox.com>]

Cover the cases where the pxar archive was uploaded as split payload
data and metadata streams. Instantiate the required reader and
decoder instances to access the metadata and payload data archives.

Signed-off-by: Christian Ebner <c.ebner@proxmox.com>
---
 proxmox-backup-client/src/mount.rs | 56 ++++++++++++++++++++++--------
 1 file changed, 41 insertions(+), 15 deletions(-)

diff --git a/proxmox-backup-client/src/mount.rs b/proxmox-backup-client/src/mount.rs
index 4a2f8335..c955a7da 100644
--- a/proxmox-backup-client/src/mount.rs
+++ b/proxmox-backup-client/src/mount.rs
@@ -219,19 +219,22 @@ async fn mount_do(param: Value, pipe: Option<OwnedFd>) -> Result<Value, Error> {
         }
     };
 
-    let server_archive_name = if archive_name.ends_with(".pxar") {
-        if target.is_none() {
-            bail!("use the 'mount' command to mount pxar archives");
-        }
-        format!("{}.didx", archive_name)
-    } else if archive_name.ends_with(".img") {
-        if target.is_some() {
-            bail!("use the 'map' command to map drive images");
-        }
-        format!("{}.fidx", archive_name)
-    } else {
-        bail!("Can only mount/map pxar archives and drive images.");
-    };
+    let server_archive_name =
+        if archive_name.ends_with(".pxar") || archive_name.ends_with(".pxar.meta") {
+            if target.is_none() {
+                bail!("use the 'mount' command to mount pxar archives");
+            }
+            format!("{}.didx", archive_name)
+        } else if archive_name.ends_with(".img") {
+            if target.is_some() {
+                bail!("use the 'map' command to map drive images");
+            }
+            format!("{}.fidx", archive_name)
+        } else if archive_name.ends_with(".pxar.pld") {
+            bail!("Use corresponding pxar.meta archive to mount.");
+        } else {
+            bail!("Can only mount/map pxar archives and drive images.");
+        };
 
     let client = BackupReader::start(
         &client,
@@ -289,14 +292,37 @@ async fn mount_do(param: Value, pipe: Option<OwnedFd>) -> Result<Value, Error> {
         let most_used = index.find_most_used_chunks(8);
         let chunk_reader = RemoteChunkReader::new(
             client.clone(),
-            crypt_config,
+            crypt_config.clone(),
             file_info.chunk_crypt_mode(),
             most_used,
         );
         let reader = BufferedDynamicReader::new(index, chunk_reader);
+
         let archive_size = reader.archive_size();
         let reader: pbs_pxar_fuse::Reader = Arc::new(BufferedDynamicReadAt::new(reader));
-        let decoder = pbs_pxar_fuse::Accessor::new(reader, archive_size).await?;
+
+        let mut decoder = pbs_pxar_fuse::Accessor::new(reader, archive_size).await?;
+
+        if let Some(archive_base_name) = server_archive_name.strip_suffix(".pxar.meta.didx") {
+            let payload_archive_name = format!("{archive_base_name}.pxar.pld.didx");
+            let payload_index = client
+                .download_dynamic_index(&manifest, &payload_archive_name)
+                .await?;
+
+            let payload_most_used = payload_index.find_most_used_chunks(8);
+            let payload_chunk_reader = RemoteChunkReader::new(
+                client.clone(),
+                crypt_config,
+                file_info.chunk_crypt_mode(),
+                payload_most_used,
+            );
+
+            let payload_reader = BufferedDynamicReader::new(payload_index, payload_chunk_reader);
+            let payload_reader: pbs_pxar_fuse::Reader =
+                Arc::new(BufferedDynamicReadAt::new(payload_reader));
+
+            decoder = decoder.redirect_payload_input(payload_reader);
+        }
 
         let session =
             pbs_pxar_fuse::Session::mount(decoder, options, false, Path::new(target.unwrap()))
-- 
2.39.2