Re: Another fatfs patch

[Marco Gerards]

Marcus Brinkmann <marcus.brinkmann@ruhr-uni-bochum.de> writes:

> Hi,
> 
> most of the patch should go in soon (hi Jeff ;), but please keep
> paying attention to the coding standard.  If you split a line, make
> sure operators go at the beginning of the next line and not at the end
> of the current line.

Ok.
 
> > I also removed some dead code in pager.c that only produced some
> > warnings.
> 
> We still might want the stats, so I fixed the warning by casting 0 to void.

Perfect! That solves warning problem too :).

> > I hope all other stuff is obvious (well, it is to me ;)). If it is
> > not, please ask me! :)
> 
> Yeah, the following doesn't make sense to me.  You claim it is about
> fixing the case where cluster size is larger than vm_page_size, but I
> don't see that being addressed here, nor do I know why it's an issue.
> Please explain that :)

Ok. The old code didn't work for clusters > 4096 because the call to
find_cluster will be split up because the pager reads the cluster in
two operations.

The cluster in a 8096 byte file will be read like this :
(first pagefault) offset: 0
(second pagefault) offset: 4096

4096(offset) + 8096(clustersize) > allocsize (8096)

The test will fault and a EIO will be the result.

I hope it is clear now.

Thanks,
Marco