"A month of sundays ago ptb wrote:"
> > Actually, I think you want to make sure, in the async case, that the
> > write to the _primary_ disk completes, as opposed to just the first
> > write...I think you could get the I/O completing out of order, right?
>
> Hmm .. that's a point. It's not a question of out of order, so much as
> we want to give the maximum chance of getting one successful write and
Ooops .. I looked up the wrong bit of code in my reply. I looked at the
final end_req, instead of the mirrored i/o end_req. Yes, don't worry,
it's already done right. The ack happens early only if there is success
to report ("uptodate" is set)..
/*
* WRITE:
*
* Let's see if all mirrored write operations have finished
* already.
*
* In any case, do the end io early on the master bh if we are
* uptodate, and AsyncIO is set on the bh. We set AsyncPhase
* when this happens, so we don't do it twice, inadvertently.
*/
if (uptodate
&& test_bit(R1BH_AsyncIO, &r1_bh->state)
&& !test_and_set_bit(R1BH_AsyncPhase, &r1_bh->state)) {
struct buffer_head *mbh = r1_bh->master_bh;
raid1_conf_t *conf = mddev_to_conf(r1_bh->mddev);
PRINTK(KERN_DEBUG "raid1: async end i/o on sectors %lu-%lu\n",
mbh->b_rsector, mbh->b_rsector + (mbh->b_size >> 9) - 1);
io_request_done(mbh->b_rsector, conf,
test_bit(R1BH_SyncPhase, &r1_bh->state));
mbh->b_end_io(mbh, uptodate);
}
Peter
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