[PATCH] XFS: Ensure we force all busy extents in range to disk

[Christoph Hellwig]

Looks good, and quite interestin that we never could it before.

Some nipicks below:

> +	/*
> +	 * search pagb_list for this slot, skipping open slots. We have to
> +	 * search the entire array as there may be multiple overlaps and
> +	 * we have to get the most recent LSN for the log force to push out
> +	 * all the transactions that span the range.
> +	 */
> +	for (bsy = pag->pagb_list; cnt; bsy++, cnt--) {

Maybe you coult convert this to a more standard loop idiom while you're
at it:

	for (cnt = 0; cnt < pag->pagb_count; cnt++) {
		bsy = &pag->pagb_list[cnt];

> +		if (!bsy->busy_tp)
> +			continue;
>  
> +		bend = bsy->busy_start + bsy->busy_length - 1;
> +		if ((bno > bend) || (uend < bsy->busy_start))

no need for the inner braces here.


And btw, the standard subsystem prefix is all lower case, xfs:, not
XFS:.

Also it seems like this patch requires your perag-lookup fixes first.
Time to get them into the for-2.6.34 git tree ASAP as a base to work
against.  That might also make it easier to work on the lockless patch
separately.