On Sat, Dec 16, 2006 at 23:28:57 +0100, Christophe Saout <christophe@xxxxxxxx> wrote: > Am Freitag, den 15.12.2006, 11:41 -0600 schrieb Bruno Wolff III: > > > I am currently using the write barrier support in ext3 and software raid > > (raid 1) and was wondering if I added dm-crypt into the mix, if I would > > still get the same guaranties for write barriers? > > For pre-2.6.19 this definitely works, as dm-crypt passes the requests > through unmodified (except for changing the data, not the ordering in > any way). > > But with 2.6.19 writes are passed through a workqueue. The more I think > about this, the more I get to the conclusion that on SMP systems the > ordering could get changed and barrier requests arrive in the wrong > order. With multiple CPUs there are multiple worker threads, which could > run encryption for write requests in parallel and thus cause the > requests arrive at underlying device in a different order. This should > by addressed. Thanks for the information. I have some SMP systems so I will need to be careful about using this. --------------------------------------------------------------------- dm-crypt mailing list - http://www.saout.de/misc/dm-crypt/ To unsubscribe, e-mail: dm-crypt-unsubscribe@xxxxxxxx For additional commands, e-mail: dm-crypt-help@xxxxxxxx
