On Wed, 2017-09-13 at 16:19 -0500, Benjamin Marzinski wrote:
> On Sun, Sep 03, 2017 at 12:38:49AM +0200, Martin Wilck wrote:
> > The fact alone that a map changes from not ready to ready does
> > not imply that it is activating.
>
> NAK on this one and
> [PATCH 21/31] 11-dm-mpath.rules: Remember DM_ACTIVATION
>
> This breaks things. It's often the case that there are devices
> stacked
> on top of multipath. When multipath loses all of its paths, if it
> doesn't have queue_if_no_path set, it can fail IO up to these higher
> devices, forcing them to react to the failure. There is no way that
> I
> know of to be able to check in udev to see if this has occured. The
> only
> safe course of action is to assume the worst and notify lvm that
> things
> are better now.
You are right, thanks. I didn't consider the case without queueing.
I see no problem with just skipping these two.
Best,
Martin
>
> A simple reproducer of the problem is something like:
>
> - create 2 multipath devices (call them mpatha and mpathb)
> - set up raid1 on top of them
>
> # pvcreate /dev/mapper/mpatha
> # pvcreate /dev/mapper/mpathc
> # vgcreate test /dev/mapper/mpathb /dev/mapper/mpatha
> # lvcreate --type raid1 -m 1 -L 1G -n raid test
>
> - verify that everything is o.k.
>
> # dd if=/dev/zero of=/dev/test/raid bs=1M count=100
> # multipath -ll
> # pvs
> # vgs
> # lvs
>
> - remove all of the path devices from mpatha
> - verify that the raid device is in partial mode
>
> # dd if=/dev/zero of=/dev/test/raid bs=1M count=100
> # multipath -ll
> # pvs
> # vgs
> # lvs
>
> - add the path devices back to the system
> - check if the raid device has recovered
>
> # multipath -ll
> # pvs
> # vgs
> # lvs
>
> With these patches, the raid device remains in partial mode, and the
> mpatha pv is still listed as unknown. If I revert these two patches,
> everything works fine again.
>
> -Ben
>
> > Signed-off-by: Martin Wilck <mwilck@xxxxxxxx>
> > ---
> > multipath/11-dm-mpath.rules | 3 +--
> > 1 file changed, 1 insertion(+), 2 deletions(-)
> >
> > diff --git a/multipath/11-dm-mpath.rules b/multipath/11-dm-
> > mpath.rules
> > index 0be22ae4..3f47744f 100644
> > --- a/multipath/11-dm-mpath.rules
> > +++ b/multipath/11-dm-mpath.rules
> > @@ -64,8 +64,7 @@ ENV{MPATH_DEVICE_READY}=="0",
> > ENV{.MPATH_DEVICE_READY_OLD}=="1",\
> > ENV{MPATH_DEVICE_READY}=="0",
> > ENV{DM_UDEV_DISABLE_OTHER_RULES_FLAG}="1"
> > ENV{MPATH_DEVICE_READY}!="0", ENV{.MPATH_DEVICE_READY_OLD}=="0",\
> > ENV{DM_UDEV_DISABLE_OTHER_RULES_FLAG}="$env{DM_DISABLE_OTH
> > ER_RULES_FLAG_OLD}",\
> > - ENV{DM_DISABLE_OTHER_RULES_FLAG_OLD}="",\
> > - ENV{DM_ACTIVATION}="1"
> > + ENV{DM_DISABLE_OTHER_RULES_FLAG_OLD}=""
> >
> > LABEL="scan_import"
> > ENV{DM_NOSCAN}!="1", GOTO="mpath_end"
> > --
> > 2.14.0
>
>
--
Dr. Martin Wilck <mwilck@xxxxxxxx>, Tel. +49 (0)911 74053 2107
SUSE Linux GmbH, GF: Felix Imendörffer, Jane Smithard, Graham Norton
HRB 21284 (AG Nürnberg)
--
dm-devel mailing list
dm-devel@xxxxxxxxxx
https://www.redhat.com/mailman/listinfo/dm-devel
