Change smbd.conf config for aio_fork to fsync-only asynchronous I/O

Author: jamesyc

src/timecapsulesmb/assets/boot/samba4/common.d/50-runtime-staging.sh

@@ -399,8 +399,9 @@ $smbd_log_level_line
     # aio_fork uses one 128 KiB shared mapping per helper and rejects larger requests.
     smb2 max read = 131072
     smb2 max write = 131072
-    aio read size = 1
-    aio write size = 1
+    # Keep reads and writes synchronous; aio_fork remains available for SMB2 flush/fsync.
+    aio read size = 0
+    aio write size = 0
     deadtime = 15
     max open files = 512
     max smbd processes = 8

tests/test_storage_runtime.py

@@ -5327,8 +5327,8 @@ def test_common_generate_smb_conf_uses_single_payload_private_db_for_all_shares(
         self.assertIn("smb2 max read = 131072", proc.stdout)
         self.assertIn("smb2 max write = 131072", proc.stdout)
         self.assertNotIn("smb2 max credits", proc.stdout)
-        self.assertIn("aio read size = 1", proc.stdout)
-        self.assertIn("aio write size = 1", proc.stdout)
+        self.assertIn("aio read size = 0", proc.stdout)
+        self.assertIn("aio write size = 0", proc.stdout)
         self.assertEqual(
             proc.stdout.count("vfs objects = catia fruit streams_xattr acl_xattr xattr_tdb aio_fork"),
             2,