From: "heming.zhao@suse.com" <heming.zhao@suse.com>
To: David Teigland <teigland@redhat.com>,
Gionatan Danti <g.danti@assyoma.it>
Cc: linux-lvm@redhat.com
Subject: Re: [linux-lvm] commit c527a0cbfc3 may have a bug
Date: Sat, 15 Feb 2020 13:22:19 +0800 [thread overview]
Message-ID: <83efdbf2-bc6f-2575-4f0a-a177da8c9cd9@suse.com> (raw)
In-Reply-To: <20200214204028.GB20792@redhat.com>
Hello David,
I accept your points. the commit c527a0cbfc3 is correct.
I still not sure if the correct fix would have unintended consequences.
I think the most of people should only config device/filter in their machine.
After this commit, machine with duplicated devs should config 2 same copies filter rule.
one copy for device/filter, another for device/global_filter. It is wield.
The legacy code lived a period of time. Many of machine use it.
I quickly check the codes, before c527a0cbfc3, lvmetad_filter is
mainly used in _pvscan_cache() with in seldom condition. All other cases use device/filter.
So I suggest
1. Does lvm2 continue to keep the wrong filter(full_filter) usage?
It can keep machine running as usual.
or may add a new config item (e.g. pvscan_compat_filter = 0|1). let user to choose
filter behaviour
2. (a lot of work) backport mainline one filter code into stable-2.02 branch.
At last,
There is a little code tip for mainline branch:
To remove the in cfg_array(devices_global_filter_CFG in lib/config/config_settings.h
It generates useless config info.
Thanks.
On 2/15/20 4:40 AM, David Teigland wrote:
> On Fri, Feb 14, 2020 at 08:34:19PM +0100, Gionatan Danti wrote:
>> Hi David, being filters one of the most asked questions, can I ask why we
>> have so many different filters, leading to such complex interactions and
>> behaviors?
>>
>> Don't get me wrong: I am sure you (the lvm team) have very good reasons to
>> do that, and I am surely missing something? But what, precisely? How should
>> we (end users) consider filters? Should we only use global_filter?
>
> You're right, filters are difficult to understand and use correctly. The
> complexity and confusion in the code is no better. With the removal of
> lvmetad in 2.03 versions (e.g. RHEL8) there's no difference between filter
> and global_filter, so that's some small improvement. But, I think filters
> should be replaced or overhauled with something easier to use and more
> useful at a technical level.
>
> I've created a bz about that and welcome thoughts about what a replacement
> should or should not be like. With input the work is more likely to be
> prioritized.
>
> https://bugzilla.redhat.com/show_bug.cgi?id=1803266
>
next prev parent reply other threads:[~2020-02-15 5:23 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <098d6e8d-2d2c-5067-1435-eefd7e2d09bc@suse.com>
2020-02-14 15:18 ` [linux-lvm] commit c527a0cbfc3 may have a bug heming.zhao
2020-02-14 19:11 ` David Teigland
2020-02-14 19:34 ` Gionatan Danti
2020-02-14 20:40 ` David Teigland
2020-02-15 5:22 ` heming.zhao [this message]
2020-02-15 12:40 ` Zdenek Kabelac
2020-02-15 19:15 ` Gionatan Danti
2020-02-15 20:19 ` Zdenek Kabelac
2020-02-16 15:17 ` Gionatan Danti
2020-02-15 20:49 ` Chris Murphy
2020-02-16 15:28 ` Gionatan Danti
2020-02-15 19:07 ` Gionatan Danti
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