[dm-devel] [PATCH] disable barriers in dm-crypt [was Re: BUG: Files corrupt after moving LVM volume to USB disk]

[Milan Broz]

> Summary of what I've managed to rule out so far:
>1. this problem does not occur without dm-crypt

Please could you test attached patch ?
Sorry for another annoying reboot :-)

Milan
--
mbroz at redhat.com



From: Milan Broz <mbroz at redhat.com>

Disable barriers in dm-crypt because of current workqueue processing
can reorder requests.

This must be addresed later but for now disabling barriers is needed
to prevent data corruption.

Signed-off-by: Milan Broz <mbroz at redhat.com>

Index: linux-2.6.20.1/drivers/md/dm-crypt.c
===================================================================
--- linux-2.6.20.1.orig/drivers/md/dm-crypt.c	2007-03-23 15:07:11.000000000 +0100
+++ linux-2.6.20.1/drivers/md/dm-crypt.c	2007-03-23 15:09:59.000000000 +0100
@@ -925,6 +925,9 @@ static int crypt_map(struct dm_target *t
 	struct crypt_config *cc = ti->private;
 	struct crypt_io *io;
 
+	if (bio_barrier(bio))
+		return -EOPNOTSUPP;
+
 	io = mempool_alloc(cc->io_pool, GFP_NOIO);
 	io->target = ti;
 	io->base_bio = bio;