diff --git a/fs/hpfs/file.c b/fs/hpfs/file.c
index 3027f4d..e4ba5fe 100644
--- a/fs/hpfs/file.c
+++ b/fs/hpfs/file.c
@@ -109,10 +109,14 @@
 {
 	struct inode *inode = mapping->host;
 
+	hpfs_lock(inode->i_sb);
+
 	if (to > inode->i_size) {
 		truncate_pagecache(inode, to, inode->i_size);
 		hpfs_truncate(inode);
 	}
+
+	hpfs_unlock(inode->i_sb);
 }
 
 static int hpfs_write_begin(struct file *file, struct address_space *mapping,