[PATCH] xfs: fix in the setting of logbsize

[Mark Tinguely]

On 06/07/15 04:16, Ales Novak wrote:
>
> On 2015-6-6 00:22, Dave Chinner wrote:
>
>> Can you give more information about the crashes? From this
>> description, I do not know whether this is a work around or a fix
>> because I don't know what code is actually causing the problem or
>> the circumstances in which the crash occurs. Hence I cannot
>> determine if your change is the right change to make or whether the
>> documetnation is simply wrong and we have a real bug we shoul dbe
>> fixing.
>
> The crashes occurred with logsunit=192k and logbsize=256k. xlog_sync()
> is calculating in logsunit units:
>
> count = XLOG_LSUNITTOB(log, XLOG_BTOLSUNIT(log, count_init));
>
> With count_init=256k, the calculated roundoff will try to cover that in
> two 192k units. This roundoff is passed to the xlog_pack_data() which
> walks the buffer and (hopefully) fails when it hits its 256k border.
>

Talked about this once before:

  http://oss.sgi.com/archives/xfs/2013-03/msg00039.html

Mark.