diff --git a/libc/include/sys/linux-syscalls.h b/libc/include/sys/linux-syscalls.h
index 6a7fc40..b90f20d 100644
--- a/libc/include/sys/linux-syscalls.h
+++ b/libc/include/sys/linux-syscalls.h
@@ -72,6 +72,7 @@
 #define __NR__newselect                   (__NR_SYSCALL_BASE + 142)
 #define __NR_ftruncate                    (__NR_SYSCALL_BASE + 93)
 #define __NR_fsync                        (__NR_SYSCALL_BASE + 118)
+#define __NR_fdatasync                    (__NR_SYSCALL_BASE + 148)
 #define __NR_fchown32                     (__NR_SYSCALL_BASE + 207)
 #define __NR_sync                         (__NR_SYSCALL_BASE + 36)
 #define __NR_fcntl64                      (__NR_SYSCALL_BASE + 221)
diff --git a/libc/include/sys/linux-unistd.h b/libc/include/sys/linux-unistd.h
index 7494efe..5e9c2f0 100644
--- a/libc/include/sys/linux-unistd.h
+++ b/libc/include/sys/linux-unistd.h
@@ -85,6 +85,7 @@
 int              ftruncate (int, off_t);
 int              getdents (unsigned int, struct dirent *, unsigned int);
 int              fsync (int);
+int              fdatasync (int);
 int              fchown (int, uid_t, gid_t);
 void             sync (void);
 int              __fcntl64 (int, int, void *);