Re: [PATCH] jbd: abort instead of waiting for nonexistent transactions

Duane Griffin
2008-08-07T00:47:19Z

2008/8/5 Stephen C. Tweedie <sct@redhat.com>:
> On Tue, 2008-08-05 at 00:51 +0100, Duane Griffin wrote:
>> The __log_wait_for_space function sits in a loop checkpointing transactions
>> until there is sufficient space free in the journal. However, if there are
>> no transactions to be processed (e.g. because the free space calculation is
>> wrong due to a corrupted filesystem) it will never progress.
>>
>> Check for space being required when no transactions are outstanding and
>> abort the journal instead of endlessly looping.
>
> I'm not sure this is the right fix --- it seems like we're fixing the
> symptoms, not the problem.
>
> The journal free space fields are reset in journal_reset() when we load
> the journal, so we can't get this situation of j_free being insufficient
> on an idle filesystem unless the main journal start/end pointers are
> corrupt.
>
> Surely we'd be better off detecting this in the first place at mount
> time, not later on during checkpoint?

Sounds sensible. In fact I've got another patch, waiting for feedback
from the reporter, that adds some very basic validation there (i.e.
first > 0 && last >= first). Not enough, I suspect. I guess we could
do much better?

> Cheers,
> Stephen

Cheers,
Duane.

--
"I never could learn to drink that blood and call it wine" - Bob Dylan