add linux sync_file_range syscall

include/fcntl.h

@@ -118,12 +118,16 @@ struct f_owner_ex {
 };
 #define FALLOC_FL_KEEP_SIZE 1
 #define FALLOC_FL_PUNCH_HOLE 2
+#define SYNC_FILE_RANGE_WAIT_BEFORE 1
+#define SYNC_FILE_RANGE_WRITE 2
+#define SYNC_FILE_RANGE_WAIT_AFTER 4
 #define SPLICE_F_MOVE 1
 #define SPLICE_F_NONBLOCK 2
 #define SPLICE_F_MORE 4
 #define SPLICE_F_GIFT 8
 int fallocate(int, int, off_t, off_t);
 ssize_t readahead(int, off_t, size_t);
+int sync_file_range(int, off_t, off_t, unsigned);
 ssize_t vmsplice(int, const struct iovec *, size_t, unsigned);
 ssize_t splice(int, off_t *, int, off_t *, size_t, unsigned);
 #define loff_t off_t

src/linux/sync_file_range.c

+#define _GNU_SOURCE
+#include <fcntl.h>
+#include "syscall.h"
+
+int sync_file_range(int fd, off_t pos, off_t len, unsigned flags)
+{
+#if defined(SYS_sync_file_range2)
+	return syscall(SYS_sync_file_range2, fd, flags,
+		__SYSCALL_LL_E(pos), __SYSCALL_LL_E(len));
+#elif defined(SYS_sync_file_range)
+	return syscall(SYS_sync_file_range, fd,
+		__SYSCALL_LL_O(pos), __SYSCALL_LL_E(len), flags);
+#else
+	return __syscall_ret(-ENOSYS);
+#endif
+}