On Thu, 2015-02-12 at 10:09 -0500, Mikulas Patocka wrote:
> It may be possible that a device claims discard support but it rejects
> discards with -EOPNOTSUPP. It happens when using loopback on ext2/ext3
> filesystem driven by the ext4 driver. It may also happen if the underlying
> devices are moved from one disk on another.
>
> If discard error happens, we reject the bio with -EOPNOTSUPP, but we do
> not degrade the array.
>
> This patch fixes failed test shell/lvconvert-repair-transient.sh in the
> lvm2 testsuite if the testsuite is extracted on an ext2 or ext3 filesystem
> and it is being driven by the ext4 driver.
>
> Signed-off-by: Mikulas Patocka <mpatocka@xxxxxxxxxx>
>
> Index: linux-2.6/drivers/md/dm-raid1.c
> ===================================================================
> --- linux-2.6.orig/drivers/md/dm-raid1.c
> +++ linux-2.6/drivers/md/dm-raid1.c
> @@ -604,6 +604,15 @@ static void write_callback(unsigned long
> return;
> }
>
> + /*
> + * If the bio is discard, return an error, but do not
> + * degrade the array.
> + */
> + if (bio->bi_rw & REQ_DISCARD) {
> + bio_endio(bio, -EOPNOTSUPP);
I think the error gets ignored, so this is probably harmless, but
shouldn't you propagate the actual error here? discard is advisory and
can fail for a variety of reasons (alignment being chief) for which
EOPNOTSUPP is inappropriate.
James
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