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From: Tomasz Pala <gotar@polanet.pl>
To: linux-btrfs@vger.kernel.org
Subject: Re: degraded permanent mount option
Date: Sun, 28 Jan 2018 01:39:10 +0100	[thread overview]
Message-ID: <20180128003910.GA31699@polanet.pl> (raw)
In-Reply-To: <pan$49d38$869e8d62$c0063169$584b8866@cox.net>

On Sat, Jan 27, 2018 at 15:22:38 +0000, Duncan wrote:

>> manages to mount degraded btrfs without problems.  They just don't try
>> to outsmart the kernel.
> 
> No kidding.
> 
> All systemd has to do is leave the mount alone that the kernel has 
> already done, instead of insisting it knows what's going on better than 
> the kernel does, and immediately umounting it.

Tell me please, if you mount -o degraded btrfs - what would
BTRFS_IOC_DEVICES_READY return?

This is not "outsmarting" nor "knowing better", on the contrary, this is "FOLLOWING the
kernel-returned data". The umounting case is simply a bug in btrfs.ko
that should change to READY state *if* someone has tried and apparently
succeeded mounting the not-ready volume.

Otherwise - how should any system part behave when you detach some drive? Insist
that "the kernel has already mounted it" and ignore kernel screaming
"the device is (not yet there/gone)"?


Just update the internal state after successful mount and this
particular problem is gone. Unless there is some race condition and the
state should be changed before the mount is announced to the userspace.

-- 
Tomasz Pala <gotar@pld-linux.org>

  reply	other threads:[~2018-01-28  0:39 UTC|newest]

Thread overview: 54+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-01-26 14:02 degraded permanent mount option Christophe Yayon
2018-01-26 14:18 ` Austin S. Hemmelgarn
2018-01-26 14:47   ` Christophe Yayon
2018-01-26 14:55     ` Austin S. Hemmelgarn
2018-01-27  5:50     ` Andrei Borzenkov
     [not found]       ` <1517035210.1252874.1249880112.19FABD13@webmail.messagingengine.com>
2018-01-27  6:43         ` Andrei Borzenkov
2018-01-27  6:48           ` Christophe Yayon
2018-01-27 10:08             ` Christophe Yayon
2018-01-27 10:26               ` Andrei Borzenkov
2018-01-27 11:06                 ` Tomasz Pala
2018-01-27 13:26                   ` Adam Borowski
2018-01-27 14:36                     ` Goffredo Baroncelli
2018-01-27 15:38                       ` Adam Borowski
2018-01-27 15:22                     ` Duncan
2018-01-28  0:39                       ` Tomasz Pala [this message]
2018-01-28 20:02                         ` Chris Murphy
2018-01-28 22:39                           ` Tomasz Pala
2018-01-29  0:00                             ` Chris Murphy
2018-01-29  8:54                               ` Tomasz Pala
2018-01-29 11:24                                 ` Adam Borowski
2018-01-29 13:05                                   ` Austin S. Hemmelgarn
2018-01-30 13:46                                     ` Tomasz Pala
2018-01-30 15:05                                       ` Austin S. Hemmelgarn
2018-01-30 16:07                                         ` Tomasz Pala
2018-01-29 17:58                                   ` Andrei Borzenkov
2018-01-29 19:00                                     ` Austin S. Hemmelgarn
2018-01-29 21:54                                       ` waxhead
2018-01-30 13:46                                         ` Austin S. Hemmelgarn
2018-01-30 19:50                                           ` Tomasz Pala
2018-01-30 20:40                                             ` Austin S. Hemmelgarn
2018-01-30 15:24                                       ` Tomasz Pala
2018-01-30 13:36                                   ` Tomasz Pala
2018-01-30  4:44                                 ` Chris Murphy
2018-01-30 15:40                                   ` Tomasz Pala
2018-01-28  8:06                       ` Andrei Borzenkov
2018-01-28 10:27                         ` Tomasz Pala
2018-01-28 15:57                         ` Duncan
2018-01-28 16:51                           ` Andrei Borzenkov
2018-01-28 20:28                         ` Chris Murphy
2018-01-28 23:13                           ` Tomasz Pala
2018-01-27 21:12                     ` Chris Murphy
2018-01-28  0:16                       ` Tomasz Pala
2018-01-27 22:42                     ` Tomasz Pala
2018-01-29 13:42                       ` Austin S. Hemmelgarn
2018-01-30 15:09                         ` Tomasz Pala
2018-01-30 16:22                           ` Tomasz Pala
2018-01-30 16:30                           ` Austin S. Hemmelgarn
2018-01-30 19:24                             ` Tomasz Pala
2018-01-30 19:40                             ` Tomasz Pala
2018-01-27 20:57                   ` Chris Murphy
2018-01-28  0:00                     ` Tomasz Pala
2018-01-28 10:43                       ` Tomasz Pala
2018-01-26 21:54 ` Chris Murphy
2018-01-26 22:03   ` Christophe Yayon

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