This reverts commit 
972b241f8441dc37a3f89dcd7e71d7f013873d13.
Quoth Chris:
	didn't take the delayed inode stuff into account
	it got an rbtree of items and it pulls things out
	so in shared mode, its hugely racey
	sorry, lets revert and fix it for real inside of btrfs
Signed-off-by: Chris Mason <clm@fb.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
 
 static const struct file_operations btrfs_dir_file_operations = {
        .llseek         = generic_file_llseek,
        .read           = generic_read_dir,
-       .iterate_shared = btrfs_real_readdir,
+       .iterate        = btrfs_real_readdir,
        .unlocked_ioctl = btrfs_ioctl,
 #ifdef CONFIG_COMPAT
        .compat_ioctl   = btrfs_ioctl,