diff --git a/fs/open.c b/fs/open.c
index 8092178ceab0fa8313b7a6f0c1e4dfcad191e9d5..ca22787d765b98378d784d5261519111d0132096 100644
--- a/fs/open.c
+++ b/fs/open.c
@@ -200,13 +200,13 @@ long do_sys_ftruncate(unsigned int fd, loff_t length, int small)
 	return error;
 }
 
-SYSCALL_DEFINE2(ftruncate, unsigned int, fd, unsigned long, length)
+SYSCALL_DEFINE2(ftruncate, unsigned int, fd, off_t, length)
 {
 	return do_sys_ftruncate(fd, length, 1);
 }
 
 #ifdef CONFIG_COMPAT
-COMPAT_SYSCALL_DEFINE2(ftruncate, unsigned int, fd, compat_ulong_t, length)
+COMPAT_SYSCALL_DEFINE2(ftruncate, unsigned int, fd, compat_off_t, length)
 {
 	return do_sys_ftruncate(fd, length, 1);
 }
diff --git a/include/linux/compat.h b/include/linux/compat.h
index 14d514233e1d4007230a83529bd61ce8da1334fd..8dffffe846ce54f8b9d2219ab19ad29afc301600 100644
--- a/include/linux/compat.h
+++ b/include/linux/compat.h
@@ -527,7 +527,7 @@ asmlinkage long compat_sys_fstatfs(unsigned int fd,
 asmlinkage long compat_sys_fstatfs64(unsigned int fd, compat_size_t sz,
 				     struct compat_statfs64 __user *buf);
 asmlinkage long compat_sys_truncate(const char __user *, compat_off_t);
-asmlinkage long compat_sys_ftruncate(unsigned int, compat_ulong_t);
+asmlinkage long compat_sys_ftruncate(unsigned int, compat_off_t);
 /* No generic prototype for truncate64, ftruncate64, fallocate */
 asmlinkage long compat_sys_openat(int dfd, const char __user *filename,
 				  int flags, umode_t mode);
diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h
index 781977975b699920ec015f8efe6fca9ea61e3db4..509733f9214f515ad2d889519d4dda2b52bdad41 100644
--- a/include/linux/syscalls.h
+++ b/include/linux/syscalls.h
@@ -447,7 +447,7 @@ asmlinkage long sys_fstatfs(unsigned int fd, struct statfs __user *buf);
 asmlinkage long sys_fstatfs64(unsigned int fd, size_t sz,
 				struct statfs64 __user *buf);
 asmlinkage long sys_truncate(const char __user *path, long length);
-asmlinkage long sys_ftruncate(unsigned int fd, unsigned long length);
+asmlinkage long sys_ftruncate(unsigned int fd, off_t length);
 #if BITS_PER_LONG == 32
 asmlinkage long sys_truncate64(const char __user *path, loff_t length);
 asmlinkage long sys_ftruncate64(unsigned int fd, loff_t length);