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From: Mike Snitzer <snitzer@redhat.com>
To: Spelic <spelic@shiftmail.org>
Cc: "Lukáš Czerner" <lczerner@redhat.com>,
	"device-mapper development" <dm-devel@redhat.com>,
	linux-ext4@vger.kernel.org, "Dave Chinner" <david@fromorbit.com>,
	xfs@oss.sgi.com
Subject: Re: Ext4 and xfs problems in dm-thin on allocation and discard
Date: Tue, 19 Jun 2012 09:34:42 -0400	[thread overview]
Message-ID: <20120619133441.GA7001@redhat.com> (raw)
In-Reply-To: <4FE062B3.7080702@shiftmail.org>

On Tue, Jun 19 2012 at  7:29am -0400,
Spelic <spelic@shiftmail.org> wrote:

> On 06/19/12 08:32, Lukáš Czerner wrote:
> >
> >So do I understand correctly that even though the discard came
> >through and thinp took advantage of it it still returns EOPNOTSUPP ?
> >This seems rather suboptimal. IIRC there was a discussion to add an
> >option to enable/disable sending discard in thinp target down
> >to the device.
> 
> I'll ask this too...
> do I understand correctly that dm-thin returns EOPNOTSUPP to the
> filesystem layer even though it is using the discard to unmap
> blocks, and at that point XFS stops sending discards down there
> (while ext4 keeps sending them)?

Are you actually seeing that?  Or are you just seizing on Lukas'
misunderstanding?

> This looks like a bug of dm-thin to me. Discards are "supported" in
> such a scenario.
> 
> Do you have a patch for dm-thin so to prevent it sending EOPTNOTSUPP ?

thinp should _not_ be sending -EOPNOTSUPP unless 'ignore_discard' is
provided as a feature when loading thin-pool's DM  table.

--
dm-devel mailing list
dm-devel@redhat.com
https://www.redhat.com/mailman/listinfo/dm-devel

WARNING: multiple messages have this Message-ID (diff)
From: Mike Snitzer <snitzer@redhat.com>
To: Spelic <spelic@shiftmail.org>
Cc: "Lukáš Czerner" <lczerner@redhat.com>,
	"device-mapper development" <dm-devel@redhat.com>,
	linux-ext4@vger.kernel.org, xfs@oss.sgi.com
Subject: Re: Ext4 and xfs problems in dm-thin on allocation and discard
Date: Tue, 19 Jun 2012 09:34:42 -0400	[thread overview]
Message-ID: <20120619133441.GA7001@redhat.com> (raw)
In-Reply-To: <4FE062B3.7080702@shiftmail.org>

On Tue, Jun 19 2012 at  7:29am -0400,
Spelic <spelic@shiftmail.org> wrote:

> On 06/19/12 08:32, Lukáš Czerner wrote:
> >
> >So do I understand correctly that even though the discard came
> >through and thinp took advantage of it it still returns EOPNOTSUPP ?
> >This seems rather suboptimal. IIRC there was a discussion to add an
> >option to enable/disable sending discard in thinp target down
> >to the device.
> 
> I'll ask this too...
> do I understand correctly that dm-thin returns EOPNOTSUPP to the
> filesystem layer even though it is using the discard to unmap
> blocks, and at that point XFS stops sending discards down there
> (while ext4 keeps sending them)?

Are you actually seeing that?  Or are you just seizing on Lukas'
misunderstanding?

> This looks like a bug of dm-thin to me. Discards are "supported" in
> such a scenario.
> 
> Do you have a patch for dm-thin so to prevent it sending EOPTNOTSUPP ?

thinp should _not_ be sending -EOPNOTSUPP unless 'ignore_discard' is
provided as a feature when loading thin-pool's DM  table.

_______________________________________________
xfs mailing list
xfs@oss.sgi.com
http://oss.sgi.com/mailman/listinfo/xfs

  parent reply	other threads:[~2012-06-19 13:34 UTC|newest]

Thread overview: 72+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-06-18 21:33 Ext4 and xfs problems in dm-thin on allocation and discard Spelic
2012-06-18 21:33 ` Spelic
2012-06-19  1:57 ` Dave Chinner
2012-06-19  1:57   ` Dave Chinner
2012-06-19  3:12   ` Mike Snitzer
2012-06-19  3:12     ` Mike Snitzer
2012-06-19  6:32     ` Lukáš Czerner
2012-06-19  6:32       ` Lukáš Czerner
2012-06-19 11:29       ` Spelic
2012-06-19 11:29         ` Spelic
2012-06-19 12:20         ` Lukáš Czerner
2012-06-19 12:20           ` Lukáš Czerner
2012-06-19 13:34         ` Mike Snitzer [this message]
2012-06-19 13:34           ` Mike Snitzer
2012-06-19 13:16       ` Mike Snitzer
2012-06-19 13:16         ` Mike Snitzer
2012-06-19 13:25         ` Lukáš Czerner
2012-06-19 13:25           ` Lukáš Czerner
2012-06-19 13:30           ` Mike Snitzer
2012-06-19 13:30             ` Mike Snitzer
2012-06-19 13:52             ` Spelic
2012-06-19 13:52               ` Spelic
2012-06-19 14:05               ` Eric Sandeen
2012-06-19 14:05                 ` Eric Sandeen
2012-06-19 14:44               ` Mike Snitzer
2012-06-19 14:44                 ` Mike Snitzer
2012-06-19 18:48                 ` Mike Snitzer
2012-06-19 18:48                   ` Mike Snitzer
2012-06-19 20:06                   ` Dave Chinner
2012-06-19 20:06                     ` Dave Chinner
2012-06-19 20:21                     ` Ted Ts'o
2012-06-19 20:21                       ` Ted Ts'o
2012-06-19 20:39                       ` Dave Chinner
2012-06-19 20:39                         ` Dave Chinner
2012-06-20  9:01                         ` Christoph Hellwig
2012-06-20  9:01                           ` Christoph Hellwig
2012-06-19 21:37                     ` Spelic
2012-06-19 21:37                       ` Spelic
2012-06-19 23:12                       ` Dave Chinner
2012-06-19 23:12                         ` Dave Chinner
2012-06-20 12:11   ` Spelic
2012-06-20 12:11     ` Spelic
2012-06-20 22:53     ` Dave Chinner
2012-06-20 22:53       ` Dave Chinner
2012-06-21 17:47       ` Mike Snitzer
2012-06-21 17:47         ` Mike Snitzer
2012-06-21 23:29         ` Dave Chinner
2012-06-21 23:29           ` Dave Chinner
2012-07-01 14:53         ` Paolo Bonzini
2012-07-01 14:53           ` Paolo Bonzini
2012-07-02 13:00           ` Mike Snitzer
2012-07-02 13:00             ` Mike Snitzer
2012-07-02 13:15             ` Paolo Bonzini
2012-07-02 13:15               ` Paolo Bonzini
2012-06-19 14:09 ` Lukáš Czerner
2012-06-19 14:09   ` Lukáš Czerner
2012-06-19 14:19   ` Ted Ts'o
2012-06-19 14:19     ` Ted Ts'o
2012-06-19 14:23     ` Eric Sandeen
2012-06-19 14:23       ` Eric Sandeen
2012-06-19 14:37     ` Lukáš Czerner
2012-06-19 14:37       ` Lukáš Czerner
2012-06-19 14:43     ` [dm-devel] " Alasdair G Kergon
2012-06-19 14:43       ` Alasdair G Kergon
2012-06-19 15:28       ` Mike Snitzer
2012-06-19 15:28         ` Mike Snitzer
2012-06-19 16:03         ` [dm-devel] " Alasdair G Kergon
2012-06-19 16:03           ` Alasdair G Kergon
2012-06-19 19:58         ` Ted Ts'o
2012-06-19 19:58           ` Ted Ts'o
2012-06-19 20:44           ` Mike Snitzer
2012-06-19 20:44             ` Mike Snitzer

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