>>>>> Stephen C Tweedie (SCT) writes:
>> journal_dirty_metadata(handle, bh)
>> {
>> transaction->t_reserved--;
>> handle->h_buffer_credits--;
>> if (jh->b_tcount > 0) {
>> /* modifed, no need to track it any more */
>> transaction-> t_outstanding_credits++;
>> jh-> b_tcount = -1;
>> }
>> }
SCT> Actually, the whole thing can be wrapped in if (jh->b_tcount > 0) {}, I
SCT> think. If we have already charged the transaction for this buffer, then
SCT> there's no need to charge the handle for it again. That's going to be
SCT> particularly important for truncate(), where we are continually updating
SCT> the same blocks (eg. bitmap, indirect blocks), so we want to make sure
SCT> that after the first journal_dirty_metadata() call, no further charge is
SCT> made.
the idea is:
1) the sooner we drop reservation, the higher probability to cover many
changes by single transaction
1) having h_buffer_credits being decremented for each modification
could help us to debug handle overflow situations
SCT> If we do that, do we in fact need t_reserved at all?
hmm. if t_outstanding_credits holds number of modified buffers,
then we need sum of all running h_buffer_credits to protect
from transaction overflow. t_reserved is sum of h_buffer_credits.
thanks, Alex
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to [EMAIL PROTECTED]
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
