From: Martin Wilck <mwilck@suse.com>
To: Hannes Reinecke <hare@suse.de>
Cc: dm-devel@redhat.com
Subject: Re: [PATCH v2 17/20] multipath.rules: find_multipaths "smart" logic
Date: Thu, 29 Mar 2018 11:15:08 +0200 [thread overview]
Message-ID: <1522314908.3669.4.camel@suse.com> (raw)
In-Reply-To: <20180329080437.51205fda@pentland.suse.de>
On Thu, 2018-03-29 at 08:04 +0200, Hannes Reinecke wrote:
>
> > The only way I see to avoid this is to try calling open(O_EXCL) on
> > the
> > path device in "multipath -u". So far we've avoided that because
> > it's
> > not completely race-free. But we're not talking about a race here,
> > but
> > a situation where some entity grabbed a device before pivot-root.
> > So we could attempt open(O_EXCL) only in the "is maybe a valid
> > path"
> > case, and only return "maybe" if that open succeeds. Otherwise we'd
> > return "no", as we already checked that the device isn't currently
> > part of a multipath map.
> >
>
> Ho-hum.
>
> Watch out when you do this; systemd will generate another event
> whenever you close this fd, and suddenly you find yourself in a
> middle
> of an event storm ...
Thanks for mentioning that.
Udev listens for inotify events for "close after write". We will do the
test with O_RDONLY|O_EXCL, so no event should be generated. Moreover,
events should only occur if udev is watching the device, which
shouldn't be the case while an event is processed (but I'm not 100%
certain about that). Anyway, I'll test this.
Cheers,
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)
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next prev parent reply other threads:[~2018-03-29 9:15 UTC|newest]
Thread overview: 45+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-03-19 15:01 [PATCH v2 00/20] multipath path classification Martin Wilck
2018-03-19 15:01 ` [PATCH v2 01/20] Revert "multipath: ignore -i if find_multipaths is set" Martin Wilck
2018-03-23 17:51 ` Benjamin Marzinski
2018-03-19 15:01 ` [PATCH v2 02/20] Revert "multipathd: imply -n " Martin Wilck
2018-03-23 17:51 ` Benjamin Marzinski
2018-03-19 15:01 ` [PATCH v2 03/20] libmultipath: should_multipath: keep existing maps Martin Wilck
2018-03-23 17:51 ` Benjamin Marzinski
2018-03-19 15:01 ` [PATCH v2 04/20] multipath -u -i: respect entries in WWIDs file Martin Wilck
2018-03-23 17:54 ` Benjamin Marzinski
2018-03-19 15:01 ` [PATCH v2 05/20] libmultipath: trigger change uevent on new device creation Martin Wilck
2018-03-19 15:01 ` [PATCH v2 06/20] libmultipath: trigger path uevent only when necessary Martin Wilck
2018-03-23 17:58 ` Benjamin Marzinski
2018-03-19 15:01 ` [PATCH v2 07/20] libmultipath: change find_multipaths option to multi-value Martin Wilck
2018-03-23 20:07 ` Benjamin Marzinski
2018-03-19 15:01 ` [PATCH v2 08/20] libmultipath: use const char* in open_file() Martin Wilck
2018-03-23 20:08 ` Benjamin Marzinski
2018-03-19 15:01 ` [PATCH v2 09/20] libmultipath: functions to indicate mapping failure in /dev/shm Martin Wilck
2018-03-19 15:01 ` [PATCH v2 10/20] libmultipath: indicate wwid failure in dm_addmap_create() Martin Wilck
2018-03-26 17:52 ` Benjamin Marzinski
2018-03-26 20:07 ` Martin Wilck
2018-03-19 15:01 ` [PATCH v2 11/20] libmultipath: don't try to set up failed wwids again Martin Wilck
2018-03-26 18:47 ` Benjamin Marzinski
2018-03-26 20:13 ` Martin Wilck
2018-03-19 15:01 ` [PATCH v2 12/20] multipath -u: common code path for result message Martin Wilck
2018-03-26 18:59 ` Benjamin Marzinski
2018-03-19 15:01 ` [PATCH v2 13/20] multipath -u: change output to environment/key format Martin Wilck
2018-03-26 19:33 ` Benjamin Marzinski
2018-03-26 20:35 ` Benjamin Marzinski
2018-03-19 15:01 ` [PATCH v2 14/20] multipath -u: add DM_MULTIPATH_DEVICE_PATH=2 for "maybe" Martin Wilck
2018-03-26 20:41 ` Benjamin Marzinski
2018-03-19 15:01 ` [PATCH v2 15/20] libmultipath: implement find_multipaths_timeout Martin Wilck
2018-03-26 22:16 ` Benjamin Marzinski
2018-03-19 15:01 ` [PATCH v2 16/20] libmultipath: enable find_multipaths "smart" Martin Wilck
2018-03-26 22:23 ` Benjamin Marzinski
2018-03-19 15:01 ` [PATCH v2 17/20] multipath.rules: find_multipaths "smart" logic Martin Wilck
2018-03-27 21:03 ` Benjamin Marzinski
2018-03-27 21:34 ` Martin Wilck
2018-03-27 23:07 ` Benjamin Marzinski
2018-03-28 14:51 ` Martin Wilck
2018-03-28 17:12 ` Benjamin Marzinski
2018-03-29 6:04 ` Hannes Reinecke
2018-03-29 9:15 ` Martin Wilck [this message]
2018-03-19 15:01 ` [PATCH v2 18/20] multipathd: decrease log level of "spurious uevent" message Martin Wilck
2018-03-19 15:01 ` [PATCH v2 19/20] libmultipath: decrease log level of uevent filter/merge messages Martin Wilck
2018-03-19 15:01 ` [PATCH v2 20/20] multipathd: decrease log level of waiter thread start/stop msgs Martin Wilck
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