Re: [PATCH 2/2] ext4: Handle nested ext4_journal_start/stop calls without a journal

[Curt Wohlgemuth <curtw@google.com>]

On Thu, Sep 17, 2009 at 10:50 PM, Andreas Dilger <adilger@sun.com> wrote:
> On Sep 17, 2009  14:55 -0700, Curt Wohlgemuth wrote:
>> This patch fixes a problem with handling nested calls to
>> ext4_journal_start/ext4_journal_stop, when there is no journal present.
>>
>>       Signed-off-by: Curt Wohlgemuth <curtw@google.com>
>> ---
>>
>> Instead of using the special value of
>>
>>         (handle_t *)0x1
>>
>> to represent a handle when there is no journal present, we now use a real
>> handle_t, so we can use its ref counting.  The h_transaction field now
>> determines if there is a journal present or not.
>
> You _could_ just use the "handle" value as a refcount, and anything less
> than, say, 4096 is considered a "special" handle.  I can't imagine the
> refcount being more than 3 or 4 even in extreme cases.

That's an elegant idea; thanks.  I'll work this up and send a patch out for it.

Thanks,
Curt

>
> Cheers, Andreas
> --
> Andreas Dilger
> Sr. Staff Engineer, Lustre Group
> Sun Microsystems of Canada, Inc.
>
>
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