From 20ee70cd1829cd414d09040460defecf9792a370 Mon Sep 17 00:00:00 2001
From: Brooks <brooks@anza.xyz>
Date: Fri, 17 May 2024 00:09:42 -0400
Subject: [PATCH] Supports archiving account storage files that are backed by
 Mmap or File (#1393)

---
 accounts-db/src/accounts_file.rs | 27 +++++++++++++++++++++++++++
 runtime/src/snapshot_utils.rs    | 28 ++++++++++++++++------------
 2 files changed, 43 insertions(+), 12 deletions(-)

diff --git a/accounts-db/src/accounts_file.rs b/accounts-db/src/accounts_file.rs
index d9d16d026c250a..09e100725655f3 100644
--- a/accounts-db/src/accounts_file.rs
+++ b/accounts-db/src/accounts_file.rs
@@ -289,6 +289,24 @@ impl AccountsFile {
                 .data_for_archive(),
         }
     }
+
+    /// Returns the way to access this accounts file when archiving
+    pub fn internals_for_archive(&self) -> InternalsForArchive {
+        // Figure out if the backing access to this accounts file is Mmap or File I/O.
+        // For now, let `can_append()` fill the gap.
+        if self.can_append() {
+            match self {
+                Self::AppendVec(av) => InternalsForArchive::Mmap(av.data_for_archive()),
+                Self::TieredStorage(ts) => InternalsForArchive::Mmap(
+                    ts.reader()
+                        .expect("must be a reader when archiving")
+                        .data_for_archive(),
+                ),
+            }
+        } else {
+            InternalsForArchive::FileIo(self.path())
+        }
+    }
 }
 
 /// An enum that creates AccountsFile instance with the specified format.
@@ -310,6 +328,15 @@ impl AccountsFileProvider {
     }
 }
 
+/// The access method to use when archiving an AccountsFile
+#[derive(Debug)]
+pub enum InternalsForArchive<'a> {
+    /// Accessing the internals is done via Mmap
+    Mmap(&'a [u8]),
+    /// Accessing the internals is done via File I/O
+    FileIo(&'a Path),
+}
+
 /// Information after storing accounts
 #[derive(Debug)]
 pub struct StoredAccountsInfo {
diff --git a/runtime/src/snapshot_utils.rs b/runtime/src/snapshot_utils.rs
index 42187302536e1a..688090977b82c5 100644
--- a/runtime/src/snapshot_utils.rs
+++ b/runtime/src/snapshot_utils.rs
@@ -20,7 +20,7 @@ use {
     solana_accounts_db::{
         account_storage::AccountStorageMap,
         accounts_db::{AccountStorageEntry, AtomicAccountsFileId},
-        accounts_file::{AccountsFile, AccountsFileError, StorageAccess},
+        accounts_file::{AccountsFile, AccountsFileError, InternalsForArchive, StorageAccess},
         hardened_unpack::{self, ParallelSelector, UnpackError},
         shared_buffer_reader::{SharedBuffer, SharedBufferReader},
         utils::{move_and_async_delete_path, ACCOUNTS_RUN_DIR, ACCOUNTS_SNAPSHOT_DIR},
@@ -823,17 +823,21 @@ pub fn archive_snapshot_package(
                     storage.slot(),
                     storage.append_vec_id(),
                 ));
-                let mut header = tar::Header::new_gnu();
-                header.set_path(path_in_archive).map_err(|err| {
-                    E::ArchiveAccountStorageFile(err, storage.path().to_path_buf())
-                })?;
-                header.set_size(storage.capacity());
-                header.set_cksum();
-                archive
-                    .append(&header, storage.accounts.data_for_archive())
-                    .map_err(|err| {
-                        E::ArchiveAccountStorageFile(err, storage.path().to_path_buf())
-                    })?;
+                match storage.accounts.internals_for_archive() {
+                    InternalsForArchive::Mmap(data) => {
+                        let mut header = tar::Header::new_gnu();
+                        header.set_path(path_in_archive).map_err(|err| {
+                            E::ArchiveAccountStorageFile(err, storage.path().to_path_buf())
+                        })?;
+                        header.set_size(storage.capacity());
+                        header.set_cksum();
+                        archive.append(&header, data)
+                    }
+                    InternalsForArchive::FileIo(path) => {
+                        archive.append_path_with_name(path, path_in_archive)
+                    }
+                }
+                .map_err(|err| E::ArchiveAccountStorageFile(err, storage.path().to_path_buf()))?;
             }
 
             archive.into_inner().map_err(E::FinishArchive)?;