On Tue, 07 Mar 2023, Song Liu wrote:
> On Sun, Mar 5, 2023 at 1:21 PM NeilBrown <neilb@xxxxxxx> wrote:
> >
> > On Sat, 04 Mar 2023, Song Liu wrote:
> > > + Jes.
> > >
> > > It appeared to me that we can assemble the array if we have any of the
> > > following:
> > > 1. Enable CONFIG_BLOCK_LEGACY_AUTOLOAD;
> > > 2. Have a valid /etc/mdadm.conf;
> > > 3. Update mdadm to handle this case. (I tried some ugly hacks, which worked but
> > > weren't clean).
> > >
> > > Since we eventually would like to get rid of CONFIG_BLOCK_LEGACY_AUTOLOAD, I
> > > think we need mdadm to handle this properly. But the logistics might
> > > be complicated, as
> > > mdadm are shipped separately.
> > >
> > > Jes, what do you think about this? AFAICT, we need to update the logic in
> > > mdopen.c:create_mddev().
> >
> > mdadm already handles this, but only if
> > CREATE names=yes
> > is present in /etc/mdadm.conf
> >
> > Maybe we should flip the default for the next mdadm release, and patch
> > the kernel (with a stable backport) to select BLOCK_LEGACY_AUTOLOAD if
> > BLK_DEV_MD=m
> > Then revert that - say - 6 months after the new mdadm is released.
>
> I like this idea. I guess we also need to select BLOCK_LEGACY_AUTOLOAD
> if BLK_DEV_MD=y?
Yes of course - sorry.
Something like the following.
Thanks,
NeilBrown
From: NeilBrown <neilb@xxxxxxx>
Subject: md: select BLOCK_LEGACY_AUTOLOAD
When BLOCK_LEGACY_AUTOLOAD is not enable, mdadm is not able to
activate new arrays unless "CREATE names=yes" appears in
mdadm.conf
As this is a regression we need to always enable BLOCK_LEGACY_AUTOLOAD
for when MD is selected - at least until mdadm is updated and the
updates widely available.
Fixes: fbdee71bb5d8 ("block: deprecate autoloading based on dev_t")
Signed-off-by: NeilBrown <neilb@xxxxxxx>
diff --git a/drivers/md/Kconfig b/drivers/md/Kconfig
index 998a5cfdbc4e..662d219c39bf 100644
--- a/drivers/md/Kconfig
+++ b/drivers/md/Kconfig
@@ -16,6 +16,10 @@ if MD
config BLK_DEV_MD
tristate "RAID support"
select BLOCK_HOLDER_DEPRECATED if SYSFS
+ # BLOCK_LEGACY_AUTOLOAD requirement should be removed
+ # after relevant mdadm enhancements - to make "names=yes"
+ # the default - are widely available.
+ select BLOCK_LEGACY_AUTOLOAD
help
This driver lets you combine several hard disk partitions into one
logical block device. This can be used to simply append one
