diff --git a/fs/fat/inode.c b/fs/fat/inode.c
index d85c8fbdcca4..353c91f0a843 100644
--- a/fs/fat/inode.c
+++ b/fs/fat/inode.c
@@ -217,7 +217,9 @@ static void fat_write_failed(struct address_space *mapping, loff_t to)
 
 	if (to > inode->i_size) {
 		truncate_pagecache(inode, inode->i_size);
+		down_write(&MSDOS_I(inode)->truncate_lock);
 		fat_truncate_blocks(inode, inode->i_size);
+		up_write(&MSDOS_I(inode)->truncate_lock);
 	}
 }