From: Christoph Hellwig <hch@infradead.org>
To: Eric Sandeen <sandeen@redhat.com>
Cc: Lukas Czerner <lczerner@redhat.com>,
Mike Snitzer <snitzer@redhat.com>,
Christoph Hellwig <hch@infradead.org>,
DarkNovaNick@gmail.com, linux-lvm@redhat.com,
linux-ext4@vger.kernel.org, Alasdair G Kergon <agk@redhat.com>,
device-mapper development <dm-devel@redhat.com>
Subject: Re: do not disable ext4 discards on first discard failure? [was: Re: dm snapshot: ignore discards issued to the snapshot-origin target]
Date: Mon, 2 May 2011 10:48:23 -0400 [thread overview]
Message-ID: <20110502144823.GA14393@infradead.org> (raw)
In-Reply-To: <4DBEC3F4.3050804@redhat.com>
On Mon, May 02, 2011 at 09:47:16AM -0500, Eric Sandeen wrote:
> I still think we need to stick with the simple rule: "EOPNOTSUPP returned for a particular bio means that it is not supported for that particular bio" - I don't know what else we can do, without creating an ambiguity...
>
> This does, however, suck for the layer calling in to a complex device.
>
> What is the overhead for sending discard bios down to a device that does not support it?
For a DM-like device there is very little overhead. The bio gets
dispatched to make_request and failed in there almost immediately.
next prev parent reply other threads:[~2011-05-02 14:48 UTC|newest]
Thread overview: 44+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20110412234706.GA11244@redhat.com>
[not found] ` <20cf301cbef67d323104a0c2ff52@google.com>
[not found] ` <20110413224025.GA18589@redhat.com>
[not found] ` <20110413234854.GA19793@redhat.com>
[not found] ` <20110426173213.GA19604@redhat.com>
[not found] ` <20110428001912.GA14659@redhat.com>
[not found] ` <20110428075355.GA2190@infradead.org>
2011-04-28 20:59 ` do not disable ext4 discards on first discard failure? [was: Re: dm snapshot: ignore discards issued to the snapshot-origin target] Mike Snitzer
2011-04-28 21:28 ` Eric Sandeen
2011-04-28 22:59 ` [linux-lvm] " Alasdair G Kergon
2011-04-28 23:01 ` Eric Sandeen
2011-04-28 23:11 ` Alasdair G Kergon
2011-04-29 1:12 ` Andreas Dilger
2011-04-29 9:30 ` Lukas Czerner
2011-04-29 12:24 ` [dm-devel] " Alasdair G Kergon
2011-04-29 12:29 ` Christoph Hellwig
2011-04-29 14:28 ` Eric Sandeen
2011-04-29 15:13 ` [linux-lvm] " Ray Morris
2011-05-04 16:33 ` Ted Ts'o
2011-05-04 16:51 ` Eric Sandeen
2011-05-04 16:57 ` Lukas Czerner
2011-05-04 17:02 ` Lukas Czerner
2011-05-02 7:16 ` Lukas Czerner
2011-05-02 8:13 ` Alasdair G Kergon
2011-05-02 8:19 ` Christoph Hellwig
2011-05-02 10:24 ` Lukas Czerner
2011-05-02 12:48 ` Mike Snitzer
2011-05-02 13:05 ` Lukas Czerner
2011-05-02 14:47 ` Eric Sandeen
2011-05-02 14:48 ` Christoph Hellwig [this message]
2011-05-02 14:58 ` Lukas Czerner
2011-05-02 13:48 ` [dm-devel] " Martin K. Petersen
2011-05-02 14:20 ` Martin K. Petersen
2011-05-02 14:39 ` [dm-devel] " Lukas Czerner
2011-05-02 14:50 ` Martin K. Petersen
2011-05-02 14:58 ` Mike Snitzer
2011-05-02 16:58 ` [dm-devel] " Martin K. Petersen
2011-05-03 8:57 ` Lukas Czerner
2011-05-04 15:10 ` Martin K. Petersen
2011-05-04 16:02 ` Mike Snitzer
2011-05-04 16:50 ` Martin K. Petersen
2011-05-04 18:03 ` Mike Snitzer
2011-05-04 17:10 ` [dm-devel] " Lukas Czerner
2011-05-04 17:32 ` Martin K. Petersen
2011-05-04 17:35 ` Lukas Czerner
2011-05-18 12:16 ` Mike Snitzer
2011-05-18 12:52 ` Mike Snitzer
2011-05-04 15:16 ` [dm-devel] " Martin K. Petersen
2011-05-04 16:12 ` Lukas Czerner
2011-05-05 8:33 ` Karel Zak
2011-05-05 10:48 ` Lukas Czerner
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