[PATCH] xfs: fix in the setting of logbsize

[Dave Chinner]

On Fri, Jun 05, 2015 at 06:03:53PM -0500, Eric Sandeen wrote:
> On 6/5/15 5:22 PM, Dave Chinner wrote:
> 
> > On Fri, Jun 05, 2015 at 03:28:45PM +0200, Ales Novak wrote:
> >> However, this rule is only mentioned in the documentation, while it
> >> could be checked during the mount.
> > 
> > Where in the documentation is that mentioned?
> 
> Documentation/filesystems/xfs.txt:
> 
>   logbsize=value
>         Set the size of each in-memory log buffer.  The size may be
>         specified in bytes, or in kilobytes with a "k" suffix.
>         Valid sizes for version 1 and version 2 logs are 16384 (16k)
>         and 32768 (32k).  Valid sizes for version 2 logs also
>         include 65536 (64k), 131072 (128k) and 262144 (256k). The
>         logbsize must be an integer multiple of the log
>         stripe unit configured at mkfs time.

Ah, ok. I'll need to look at the history of that, because I think I
can see what it is intended to mean, but the "power-of-two" sizes
that are enforced will also enforce the "integer multiple" part,
too. I think it was more intended for people using wierd stripe
units (e.g. 96k) to say the equivalent on 2x96k is a valid log
buffer size. I suspect we need to revisit both the code and the
documentation here....

Cheers,

Dave.

-- 
Dave Chinner
david at fromorbit.com