Enable safe inode cleanup

This patch facilitates the proper cleanup and removal of the inode itself
as well as any associated cached page data.

inode.c

@@ -613,6 +613,7 @@ static int simplefs_unlink(struct inode *dir, struct dentry *dentry)
     inode->i_ctime.tv_sec = inode->i_mtime.tv_sec = inode->i_atime.tv_sec = 0;
 #endif
 
+    inode_dec_link_count(inode);
     drop_nlink(inode);
     mark_inode_dirty(inode);