From: Martin Wilck <mwilck@suse.com>
To: Benjamin Marzinski <bmarzins@redhat.com>, Hannes Reinecke <hare@suse.de>
Cc: dm-devel@redhat.com
Subject: Re: [PATCH 09/31] libmultipath: support MPATH_UDEV_NO_PATHS_FLAG on map creation
Date: Thu, 14 Sep 2017 13:53:59 +0200 [thread overview]
Message-ID: <1505390039.4493.6.camel@suse.com> (raw)
In-Reply-To: <20170913203303.GK3145@octiron.msp.redhat.com>
On Wed, 2017-09-13 at 15:33 -0500, Benjamin Marzinski wrote:
> On Sun, Sep 03, 2017 at 12:38:38AM +0200, Martin Wilck wrote:
> > Some vendor kernels (e.g. SUSE) have supported loading multipath
> > maps without valid paths for a long time. Without that feature,
> > problems can occur in failover scenarios when multipathd tries
> > to (re)load maps after device failure/removal, because multipathd's
> > attempts to reload the configuration may fail unnecessarily.
> > The discussion in the kernel community is ongoing
> > (see e.g. https://patchwork.kernel.org/patch/4579551/).
>
> I don't object to the patch itself, but I'm pretty sure that this
> solution to multipath's reloading issues is not currently under
> consideration upstream. It got Naked, and I wrote and alternative
> method, which got accepted
>
> https://www.redhat.com/archives/dm-devel/2014-September/msg00094.html
>
> Do you still need this patch?
This is a hard question to answer. We've been using Hannes' approach in
SLES for years with no problems, and it's hard to predict whether or
not dropping it would cause regressions. Hannes is more qualified than
myself to comment on the kernel side details.
> The solution that's currently upstream
> doesn't allow you to load new devices with failed paths, but it
> avoids
> the issues that caused the SUSE patch to get Nak'ed. The multipath
> user-space code already won't allow you to create a multipath device
> if
> it can't open the path device, so I don't see why you need the
> ability
> for the kernel to allow creation of devices with only failed paths. I
> admit, there is a small window where multipath could open the path
> device, and then the path device could fail before the load is sent
> to
> the kernel. In this case, with your patch, you could still create
> the
> device (I believe). But the much more likely case, where the path
> has
> failed before multipath tries to open it, is still there. I don't see
> the benefit of adding code to fix the corner case, while the common
> case
> still doesn't work. Is there some other case where your patch is
> helpful
> that I'm missing?
>
> At any rate. Even if that kernel patch doesn't go upstream, I have no
> objection to changing the code so the udev rules are robust enough to
> handle this situation.
>
> ACK
Thanks a lot.
Martin
--
Dr. Martin Wilck <mwilck@suse.com>, 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@redhat.com
https://www.redhat.com/mailman/listinfo/dm-devel
next prev parent reply other threads:[~2017-09-14 11:53 UTC|newest]
Thread overview: 51+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-09-02 22:38 [PATCH 00/31] multipath/kpartx udev rules cleanup, and fixes Martin Wilck
2017-09-02 22:38 ` [PATCH 01/31] libmultipath: fix partition_delimiter config option Martin Wilck
2017-09-02 22:38 ` [PATCH 02/31] kpartx: helper functions for name and uuid generation Martin Wilck
2017-09-02 22:38 ` [PATCH 03/31] kpartx: search partitions by UUID, and rename Martin Wilck
2017-09-02 22:38 ` [PATCH 04/31] test-kpartx: add tests for renaming functionality Martin Wilck
2017-09-02 22:38 ` [PATCH 05/31] kpartx: fix a corner case when renaming partitions Martin Wilck
2017-09-02 22:38 ` [PATCH 06/31] kpartx: fix part deletion without partition table Martin Wilck
2017-09-02 22:38 ` [PATCH 07/31] test-kpartx: test deletion with empty part table Martin Wilck
2017-09-02 22:38 ` [PATCH 08/31] kpartx: only recognize dasd part table on DASD Martin Wilck
2017-09-02 22:38 ` [PATCH 09/31] libmultipath: support MPATH_UDEV_NO_PATHS_FLAG on map creation Martin Wilck
2017-09-13 20:33 ` Benjamin Marzinski
2017-09-14 11:53 ` Martin Wilck [this message]
2017-09-02 22:38 ` [PATCH 10/31] libmultipath: add get_udev_device Martin Wilck
2017-09-02 22:38 ` [PATCH 11/31] libmultipath: get_refwwid: use get_udev_device Martin Wilck
2017-09-02 22:38 ` [PATCH 12/31] libmultipath: use const char* in some dm helpers Martin Wilck
2017-09-02 22:38 ` [PATCH 13/31] libmultipath: add DI_NOIO flag for pathinfo Martin Wilck
2017-09-02 22:38 ` [PATCH 14/31] libmultipath: add dm_get_multipath Martin Wilck
2017-09-02 22:38 ` [PATCH 15/31] multipath: implement "check usable paths" (-C/-U) Martin Wilck
2017-09-13 20:53 ` Benjamin Marzinski
2017-09-14 11:47 ` Martin Wilck
2017-09-15 21:06 ` Benjamin Marzinski
2017-09-02 22:38 ` [PATCH 16/31] 11-dm-mpath.rules: multipath -U for READY check Martin Wilck
2017-09-02 22:38 ` [PATCH 17/31] 11-dm-mpath.rules: import more ID_FS_xxx vars from db Martin Wilck
2017-09-02 22:38 ` [PATCH 18/31] 11-dm-mpath.rules: no need to test before IMPORT Martin Wilck
2017-09-02 22:38 ` [PATCH 19/31] 11-dm-mpath.rules: handle new maps with READY==0 Martin Wilck
2017-09-02 22:38 ` [PATCH 20/31] 11-dm-mpath.rules: don't set READY->ACTIVATION Martin Wilck
2017-09-13 21:19 ` Benjamin Marzinski
2017-09-13 21:33 ` Martin Wilck
2017-09-14 12:48 ` Martin Wilck
2017-09-15 20:33 ` Benjamin Marzinski
2017-09-02 22:38 ` [PATCH 21/31] 11-dm-mpath.rules: Remember DM_ACTIVATION Martin Wilck
2017-09-13 21:19 ` Benjamin Marzinski
2017-09-14 13:06 ` Martin Wilck
2017-09-15 20:40 ` Benjamin Marzinski
2017-09-18 19:54 ` Martin Wilck
2017-09-02 22:38 ` [PATCH 22/31] multipath.rules: set ID_FS_TYPE to "mpath_member" Martin Wilck
2017-09-02 22:38 ` [PATCH 23/31] kpartx.rules: don't rely on DM_DEPS and DM_TABLE_STATE Martin Wilck
2017-09-02 22:38 ` [PATCH 24/31] kpartx.rules: respect DM_UDEV_LOW_PRIORITY_FLAG Martin Wilck
2017-09-02 22:38 ` [PATCH 25/31] kpartx.rules: improved logic for by-uuid and by-label links Martin Wilck
2017-09-02 22:38 ` [PATCH 26/31] kpartx.rules: create by-partuuid and by-partlabel symlinks Martin Wilck
2017-09-02 22:38 ` [PATCH 27/31] kpartx.rules: generate type-name links only for multipath devices Martin Wilck
2017-09-02 22:38 ` [PATCH 28/31] kpartx.rules: fix logic for adding partitions Martin Wilck
2017-09-02 22:38 ` [PATCH 29/31] multipath/kpartx rules: avoid superfluous scanning Martin Wilck
2017-09-02 22:38 ` [PATCH 30/31] kpartx/del-part-nodes.rules: new udev file Martin Wilck
2017-09-13 21:23 ` Benjamin Marzinski
2017-09-02 22:39 ` [PATCH 31/31] kpartx.rules: move symlink code to other files Martin Wilck
2017-09-13 21:26 ` Benjamin Marzinski
2017-09-13 21:28 ` [PATCH 00/31] multipath/kpartx udev rules cleanup, and fixes Benjamin Marzinski
2017-09-14 11:56 ` Martin Wilck
2017-09-14 20:00 ` [PATCH v2 30/31] kpartx/del-part-nodes.rules: new udev file Martin Wilck
2017-09-14 20:00 ` [PATCH v2 31/31] kpartx.rules: move symlink code to other files Martin Wilck
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=1505390039.4493.6.camel@suse.com \
--to=mwilck@suse.com \
--cc=bmarzins@redhat.com \
--cc=dm-devel@redhat.com \
--cc=hare@suse.de \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.