From d100f7a2c8681b2d4dd1bf03797ef8fb3157358b Mon Sep 17 00:00:00 2001
From: Damien Elmes <gpg@ankiweb.net>
Date: Sat, 19 Mar 2022 23:29:16 +1000
Subject: [PATCH] Don't fsync media files on import

I was seeing import speeds of only 10-20 files a second before this
change.
---
 rslib/src/import_export/package/colpkg/export.rs |  2 +-
 rslib/src/import_export/package/colpkg/import.rs |  4 ++--
 rslib/src/io.rs                                  | 15 ++++++++++++---
 rslib/src/sync/mod.rs                            |  2 +-
 4 files changed, 16 insertions(+), 7 deletions(-)

diff --git a/rslib/src/import_export/package/colpkg/export.rs b/rslib/src/import_export/package/colpkg/export.rs
index f73cd2671..e2247bc83 100644
--- a/rslib/src/import_export/package/colpkg/export.rs
+++ b/rslib/src/import_export/package/colpkg/export.rs
@@ -63,7 +63,7 @@ impl Collection {
             &tr,
             progress_fn,
         )?;
-        atomic_rename(temp_colpkg, colpkg_name)
+        atomic_rename(temp_colpkg, colpkg_name, true)
     }
 }
 
diff --git a/rslib/src/import_export/package/colpkg/import.rs b/rslib/src/import_export/package/colpkg/import.rs
index c013a95ed..441aa4a2d 100644
--- a/rslib/src/import_export/package/colpkg/import.rs
+++ b/rslib/src/import_export/package/colpkg/import.rs
@@ -75,7 +75,7 @@ pub fn import_colpkg(
     let media_folder = Path::new(target_media_folder);
     restore_media(&meta, progress_fn, &mut archive, media_folder)?;
 
-    atomic_rename(tempfile, &col_path)
+    atomic_rename(tempfile, &col_path, true)
 }
 
 fn check_collection(col_path: &Path) -> Result<()> {
@@ -143,7 +143,7 @@ fn restore_media_file(meta: &Meta, zip_file: &mut ZipFile, path: &Path) -> Resul
     }
     .map_err(|err| AnkiError::file_io_error(err, path))?;
 
-    atomic_rename(tempfile, path)
+    atomic_rename(tempfile, path, false)
 }
 
 impl MediaEntry {
diff --git a/rslib/src/io.rs b/rslib/src/io.rs
index 367d5d67a..8a68ffdb3 100644
--- a/rslib/src/io.rs
+++ b/rslib/src/io.rs
@@ -14,11 +14,20 @@ pub(crate) fn tempfile_in_parent_of(file: &Path) -> Result<NamedTempFile> {
     NamedTempFile::new_in(dir).map_err(|err| AnkiError::file_io_error(err, dir))
 }
 
-pub(crate) fn atomic_rename(file: NamedTempFile, target: &Path) -> Result<()> {
-    file.as_file().sync_all()?;
+/// Atomically replace the target path with the provided temp file.
+///
+/// If `fsync` is true, file data is synced to disk prior to renaming, and the
+/// folder is synced on UNIX platforms after renaming. This minimizes the
+/// chances of corruption if there is a crash or power loss directly after the
+/// op, but it can be considerably slower.
+pub(crate) fn atomic_rename(file: NamedTempFile, target: &Path, fsync: bool) -> Result<()> {
+    if fsync {
+        file.as_file().sync_all()?;
+    }
     file.persist(&target)
         .map_err(|err| AnkiError::IoError(format!("write {target:?} failed: {err}")))?;
-    if !cfg!(windows) {
+    #[cfg(not(windows))]
+    if fsync {
         if let Some(parent) = target.parent() {
             std::fs::File::open(parent)
                 .and_then(|file| file.sync_all())
diff --git a/rslib/src/sync/mod.rs b/rslib/src/sync/mod.rs
index 3e66a2226..538790a0c 100644
--- a/rslib/src/sync/mod.rs
+++ b/rslib/src/sync/mod.rs
@@ -680,7 +680,7 @@ impl Collection {
         let db = open_and_check_sqlite_file(out_file.path())?;
         db.execute_batch("update col set ls=mod")?;
         drop(db);
-        atomic_rename(out_file, &col_path)?;
+        atomic_rename(out_file, &col_path, true)?;
 
         Ok(())
     }