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From: Martin Wilck <mwilck@suse.com>
To: Benjamin Marzinski <bmarzins@redhat.com>
Cc: dm-devel@redhat.com, Julian Andres Klode <julian.klode@canonical.com>
Subject: Re: [PATCH v3 17/20] multipath -u: test if path is busy
Date: Fri, 13 Apr 2018 19:57:03 +0200	[thread overview]
Message-ID: <1523642223.1518.9.camel@suse.com> (raw)
In-Reply-To: <20180413155335.GC3103@octiron.msp.redhat.com>

On Fri, 2018-04-13 at 10:53 -0500, Benjamin Marzinski wrote:
> On Fri, Apr 13, 2018 at 12:17:54AM +0200, Martin Wilck wrote:
> > 
> > As I said already, I don't understand why you say that.
> > 
> > I can assert that if is_failed_wwid() returns true, multipathd has
> > definitely tried and failed since the last reboot, and no (other
> > instance of) multipathd or multipath has succeeded since then.
> > 
> > If is_failed_wwid() returns false, it's possible that the map
> > already
> > exists (see patch 18), or that previous/current instances of
> > multipathd
> > simply didn't try -  we have to check by other means.
> 
> I probably shouldn't have brought up is_failed_wwid() up here at all.
> It has really nothing to do with my main point.
> 
> But just to rehash this again, you do agree that multipathd can get a
> uevent for for a path device, recognize that it should create a
> multipath device on it, and then fail somewhere in ev_add_path before
> it
> get around to calling domap, right? If this happens, multipathd won't
> automatically try to create that device again until either it gets
> another add event for a path in that device, or it is
> reconfigured.  In
> this case the is_failed_wwid() result would make it seem like
> multipathd
> might still be waiting to create this device, when in truth, that
> won't
> happen.

I agree. (is_failed_wwid(refwwid) != WWID_IS_FAILED) doesn't really
mean a lot, it happens in many different situations. Luckily we test
only for (is_failed_wwid(refwwid) == WWID_IS_FAILED), which is well-
defined, and make further checks otherwise.

Regards
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
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https://www.redhat.com/mailman/listinfo/dm-devel

  reply	other threads:[~2018-04-13 17:57 UTC|newest]

Thread overview: 25+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-04-02 19:50 [PATCH v3 00/20] multipath path classification Martin Wilck
2018-04-02 19:50 ` [PATCH v3 01/20] Revert "multipath: ignore -i if find_multipaths is set" Martin Wilck
2018-04-02 19:50 ` [PATCH v3 02/20] Revert "multipathd: imply -n " Martin Wilck
2018-04-02 19:50 ` [PATCH v3 03/20] libmultipath: should_multipath: keep existing maps Martin Wilck
2018-04-02 19:50 ` [PATCH v3 04/20] multipath -u -i: respect entries in WWIDs file Martin Wilck
2018-04-02 19:50 ` [PATCH v3 05/20] libmultipath: trigger change uevent on new device creation Martin Wilck
2018-04-02 19:50 ` [PATCH v3 06/20] libmultipath: trigger path uevent only when necessary Martin Wilck
2018-04-02 19:50 ` [PATCH v3 07/20] libmultipath: change find_multipaths option to multi-value Martin Wilck
2018-04-02 19:50 ` [PATCH v3 08/20] libmultipath: use const char* in open_file() Martin Wilck
2018-04-02 19:50 ` [PATCH v3 09/20] libmultipath: functions to indicate mapping failure in /dev/shm Martin Wilck
2018-04-02 19:50 ` [PATCH v3 10/20] libmultipath: indicate wwid failure in dm_addmap_create() Martin Wilck
2018-04-02 19:50 ` [PATCH v3 11/20] multipath -u: common code path for result message Martin Wilck
2018-04-02 19:50 ` [PATCH v3 12/20] multipath -u: change output to environment/key format Martin Wilck
2018-04-02 19:50 ` [PATCH v3 13/20] multipath -u: treat failed wwids as invalid Martin Wilck
2018-04-02 19:50 ` [PATCH v3 14/20] multipath -u: add DM_MULTIPATH_DEVICE_PATH=2 for "maybe" Martin Wilck
2018-04-02 19:50 ` [PATCH v3 15/20] libmultipath: implement find_multipaths_timeout Martin Wilck
2018-04-02 19:50 ` [PATCH v3 16/20] multipath -u : set FIND_MULTIPATHS_WAIT_UNTIL from /dev/shm Martin Wilck
2018-04-02 19:50 ` [PATCH v3 17/20] multipath -u: test if path is busy Martin Wilck
2018-04-12 18:41   ` Benjamin Marzinski
2018-04-12 22:17     ` Martin Wilck
2018-04-13 15:53       ` Benjamin Marzinski
2018-04-13 17:57         ` Martin Wilck [this message]
2018-04-02 19:50 ` [PATCH v3 18/20] multipath -u: quick check if path is multipathed Martin Wilck
2018-04-02 19:50 ` [PATCH v3 19/20] libmultipath: enable find_multipaths "smart" Martin Wilck
2018-04-02 19:50 ` [PATCH v3 20/20] multipath.rules: find_multipaths "smart" logic Martin Wilck

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