CVE-2023-52569

In the Linux kernel, the following vulnerability has been resolved: btrfs:
remove BUG() after failure to insert delayed dir index item Instead of
calling BUG() when we fail to insert a delayed dir index item into the
delayed node’s tree, we can just release all the resources we have
allocated/acquired before and return the error to the caller. This is fine
because all existing call chains undo anything they have done before
calling btrfs_insert_delayed_dir_index() or BUG_ON (when creating pending
snapshots in the transaction commit path). So remove the BUG() call and do
proper error handling. This relates to a syzbot report linked below, but
does not fix it because it only prevents hitting a BUG(), it does not fix
the issue where somehow we attempt to use twice the same index number for
different index items.