Re: Problems with hfsplus on ipods in 2.6.38+

From: Daniel Barkalow
Date: Fri Jul 15 2011 - 11:51:15 EST


On Fri, 15 Jul 2011, Seth Forshee wrote:

> On Thu, Jul 14, 2011 at 09:26:11PM -0400, Daniel Barkalow wrote:
> > Okay, I've applied that patch set, and it worked for me without any issues
> > thus far. If you're interested in the debugging output from a device that
> > doesn't work with vanilla but doesn't oops or panic with that patch set,
> > it's attached. I'm using 32-bit x86, if that helps for tracking down
> > differences.
>
> Hrm, looks like I used %lu for sector_t instead of %llu, and that's
> messing up the output on 32-bit builds. What I am able to see looks
> correct though. I put up a new version of the patches with the output
> fixed along with a new build on the bug.
>
> I've had some success producing problems using scsi_debug with a 64-bit
> build, specifically with 1K or 2K sectors. Actually a lot of odd things
> happen with those sector sizes, and they happen whether using my patch
> or reverting the two patches that change hfsplus to using bio, so those
> problems seem unrelated. What I see is that the free/used space numbers
> reported by df don't make sense given the actual files I've copied to
> the volume. If I "fill" the volume (in quotes because really I haven't
> copied in enough data to fill the volume, but it says it's full anyway)
> df reports complete garbage. Then if I proceed to remove all files from
> the volume df still reports that 50% of the space is used. These
> problems aren't present with 512 byte or 4K sectors.
>
> What I also see are GPFs in memory allocation code, which is what I
> believe others have seen with my patch, and so far I haven't seen those
> with the reversions. So I'm suspecting memory corruption, but I don't
> yet see where the corruption is coming form. I found one problem, but I
> don't suspect it's responsible for the GPFs.

A while later, somewhat after I'd unmounted the filesystem (and sent the
email), I got some memory allocation oopses, also, followed eventually by
some sort of hang (userspace not working but alt-sysrq did work). So I
agree with the memory corruption idea. Do you want corrected debugging
output, or any other information from my actual device, or are you set
with scsi_debug for now?

-Daniel
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