diff --git a/mm/truncate.c b/mm/truncate.c
index 937571b..ba887bf 100644
--- a/mm/truncate.c
+++ b/mm/truncate.c
@@ -541,28 +541,48 @@
 EXPORT_SYMBOL(truncate_pagecache);
 
 /**
+ * truncate_setsize - update inode and pagecache for a new file size
+ * @inode: inode
+ * @newsize: new file size
+ *
+ * truncate_setsize updastes i_size update and performs pagecache
+ * truncation (if necessary) for a file size updates. It will be
+ * typically be called from the filesystem's setattr function when
+ * ATTR_SIZE is passed in.
+ *
+ * Must be called with inode_mutex held and after all filesystem
+ * specific block truncation has been performed.
+ */
+void truncate_setsize(struct inode *inode, loff_t newsize)
+{
+	loff_t oldsize;
+
+	oldsize = inode->i_size;
+	i_size_write(inode, newsize);
+
+	truncate_pagecache(inode, oldsize, newsize);
+}
+EXPORT_SYMBOL(truncate_setsize);
+
+/**
  * vmtruncate - unmap mappings "freed" by truncate() syscall
  * @inode: inode of the file used
  * @offset: file offset to start truncating
  *
- * NOTE! We have to be ready to update the memory sharing
- * between the file and the memory map for a potential last
- * incomplete page.  Ugly, but necessary.
- *
- * This function is deprecated and simple_setsize or truncate_pagecache
- * should be used instead.
+ * This function is deprecated and truncate_setsize or truncate_pagecache
+ * should be used instead, together with filesystem specific block truncation.
  */
 int vmtruncate(struct inode *inode, loff_t offset)
 {
 	int error;
 
-	error = simple_setsize(inode, offset);
+	error = inode_newsize_ok(inode, offset);
 	if (error)
 		return error;
 
+	truncate_setsize(inode, offset);
 	if (inode->i_op->truncate)
 		inode->i_op->truncate(inode);
-
-	return error;
+	return 0;
 }
 EXPORT_SYMBOL(vmtruncate);