[dm-devel] [PATCH 0/8] dm: request-based dm-multipath
Kiyoshi Ueda
k-ueda at ct.jp.nec.com
Tue Mar 10 06:10:12 UTC 2009
Hi Hannes,
On 2009/01/30 17:05 +0900, Kiyoshi Ueda wrote:
>>> o kernel panic occurs by frequent table swapping during heavy I/Os.
>>>
>> That's probably fixed by this patch:
>>
>> --- linux-2.6.27/drivers/md/dm.c.orig 2009-01-23 15:59:22.741461315 +0100
>> +++ linux-2.6.27/drivers/md/dm.c 2009-01-26 09:03:02.787605723 +0100
>> @@ -714,13 +714,14 @@ static void free_bio_clone(struct reques
>> struct dm_rq_target_io *tio = clone->end_io_data;
>> struct mapped_device *md = tio->md;
>> struct bio *bio;
>> - struct dm_clone_bio_info *info;
>>
>> while ((bio = clone->bio) != NULL) {
>> clone->bio = bio->bi_next;
>>
>> - info = bio->bi_private;
>> - free_bio_info(md, info);
>> + if (bio->bi_private) {
>> + struct dm_clone_bio_info *info = bio->bi_private;
>> + free_bio_info(md, info);
>> + }
>>
>> bio->bi_private = md->bs;
>> bio_put(bio);
>>
>> The info field is not necessarily filled here, so we have to check for it
>> explicitly.
>>
>> With these two patches request-based multipathing have survived all stress-tests
>> so far. Except on mainframe (zfcp), but that's more a driver-related thing.
My problem was different from that one, and I have fixed my problem.
Do you hit some problem without the patch above?
If so, that should be a programming bug and we need to fix it. Otherwise,
we should be leaking a memory (since all cloned bio should always have
the dm_clone_bio_info structure in ->bi_private).
Thanks,
Kiyoshi Ueda
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