Re: [PATCH 25/25] xfs: add write verifiers to log recovery

[Christoph Hellwig <hch@xxxxxxxxxxxxx>]

> +      * during log recovery, we don't have a quotainfo structure to
> +      * pull the number of dquots per buffer out of, so we have to calculate
> +      * it directly.
> +      */
> +     if (mp->m_log->l_flags & XLOG_ACTIVE_RECOVERY) {
> +             dquots_per_buf = BBTOB(bp->b_length);
> +             do_div(dquots_per_buf, sizeof(xfs_dqblk_t));

No need for do_div when dividing a 32-bit value by a constant.

I'd be almost tempted to do the calculation unconditionally to make the
code cleaner, too.

> + * There is no easy way to do this except for trying a bunch of magic
> + * number matches....

How do we make sure buffers used for the symlink or attr payload don't
match this?