diff --git a/fs/fs.c b/fs/fs.c
index ffdfa2c..779f264 100644
--- a/fs/fs.c
+++ b/fs/fs.c
@@ -923,7 +923,7 @@
 }
 EXPORT_SYMBOL(lseek);
 
-int erase(int fd, size_t count, unsigned long offset)
+int erase(int fd, size_t count, loff_t offset)
 {
 	struct fs_driver_d *fsdrv;
 	FILE *f;
@@ -950,7 +950,7 @@
 }
 EXPORT_SYMBOL(erase);
 
-int protect(int fd, size_t count, unsigned long offset, int prot)
+int protect(int fd, size_t count, loff_t offset, int prot)
 {
 	struct fs_driver_d *fsdrv;
 	FILE *f;
diff --git a/include/fs.h b/include/fs.h
index 63e35ca..b8a95a2 100644
--- a/include/fs.h
+++ b/include/fs.h
@@ -147,8 +147,8 @@
 int umount(const char *pathname);
 
 /* not-so-standard functions */
-int erase(int fd, size_t count, unsigned long offset);
-int protect(int fd, size_t count, unsigned long offset, int prot);
+int erase(int fd, size_t count, loff_t offset);
+int protect(int fd, size_t count, loff_t offset, int prot);
 int protect_file(const char *file, int prot);
 void *memmap(int fd, int flags);