From 662de15ac9528f541b58b12e439b51dc8bd3c023 Mon Sep 17 00:00:00 2001
From: John Chau <john@harmon.hk>
Date: Sat, 5 Oct 2024 20:01:44 +0900
Subject: [PATCH] Add option to call fsync() before close() during
 mtp_op_SendObject()

---
 conf/umtprd.conf                       |  8 ++++++++
 inc/mtp.h                              |  2 ++
 src/mtp_cfg.c                          | 12 +++++++++++-
 src/mtp_operations/mtp_op_sendobject.c |  1 +
 4 files changed, 22 insertions(+), 1 deletion(-)

diff --git a/conf/umtprd.conf b/conf/umtprd.conf
index aebded4..7c527c4 100644
--- a/conf/umtprd.conf
+++ b/conf/umtprd.conf
@@ -81,6 +81,14 @@ usb_dev_version 0x3008
 
 # no_inotify 0x1
 
+# Sync when close
+# Set this option to 0x1 to request all file data to be flushed from the RAM buffer to the
+# internal storage after transfer is completed, this prevents data loss in the case where
+# user un-plugged a non-battery-powered device too soon when there are still buffered data
+# stayed in the RAM
+
+# sync_when_close 0x0 
+
 #
 # Internal buffers size
 #
diff --git a/inc/mtp.h b/inc/mtp.h
index 1a30fc1..6381e2b 100644
--- a/inc/mtp.h
+++ b/inc/mtp.h
@@ -135,6 +135,8 @@ typedef struct mtp_ctx_
 
 	int no_inotify;
 
+	int sync_when_close;
+
 	int uid,euid;
 	int gid,egid;
 
diff --git a/src/mtp_cfg.c b/src/mtp_cfg.c
index 235d552..e333232 100644
--- a/src/mtp_cfg.c
+++ b/src/mtp_cfg.c
@@ -78,7 +78,9 @@ enum
 	DEFAULT_UID_CMD,
 	DEFAULT_GID_CMD,
 
-	NO_INOTIFY
+	NO_INOTIFY,
+
+	SYNC_WHEN_CLOSE
 
 };
 
@@ -478,6 +480,9 @@ static int get_hex_param(mtp_ctx * context, char * line,int cmd)
 				context->no_inotify = param_value;
 			break;
 
+			case SYNC_WHEN_CLOSE:
+				context->sync_when_close = param_value;
+
 		}
 	}
 
@@ -617,6 +622,8 @@ kw_list kwlist[] =
 
 	{"no_inotify",             get_hex_param,   NO_INOTIFY},
 
+	{"sync_when_close",        get_hex_param,   SYNC_WHEN_CLOSE},
+
 	{ 0, 0, 0 }
 };
 
@@ -702,6 +709,7 @@ int mtp_load_config_file(mtp_ctx * context, const char * conffile)
 	context->default_uid = -1;
 
 	context->no_inotify = 0;
+	context->sync_when_close = 0;
 
 	f = fopen(conffile, "r");
 	if(f)
@@ -787,5 +795,7 @@ int mtp_load_config_file(mtp_ctx * context, const char * conffile)
 
 	PRINT_MSG("inotify : %s",context->no_inotify?"no":"yes");
 
+	PRINT_MSG("Sync when close : %s",context->sync_when_close?"yes":"no");
+
 	return err;
 }
diff --git a/src/mtp_operations/mtp_op_sendobject.c b/src/mtp_operations/mtp_op_sendobject.c
index 8363e15..c2e57ab 100644
--- a/src/mtp_operations/mtp_op_sendobject.c
+++ b/src/mtp_operations/mtp_op_sendobject.c
@@ -148,6 +148,7 @@ uint32_t mtp_op_SendObject(mtp_ctx * ctx,MTP_PACKET_HEADER * mtp_packet_hdr, int
 
 							ctx->transferring_file_data = 0;
 
+							if (ctx->sync_when_close) fsync(file);
 							close(file);
 
 							if(ctx->usb_cfg.val_umask >= 0)