From: Christoph Hellwig <hch@infradead.org>
To: Matthew Wilcox <matthew@wil.cx>
Cc: Christoph Hellwig <hch@infradead.org>,
"Martin K. Petersen" <martin.petersen@oracle.com>,
jens.axboe@oracle.com, james.bottomley@hansenpartnership.com,
willy@wil.cx, jgarzik@pobox.com, sandeen@redhat.com,
rwheeler@redhat.com, linux-ide@vger.kernel.org,
linux-scsi@vger.kernel.org
Subject: Re: [PATCH 1/4] block: Allow devices to indicate whether discarded blocks are zeroed
Date: Mon, 23 Nov 2009 12:05:01 -0500 [thread overview]
Message-ID: <20091123170501.GA32604@infradead.org> (raw)
In-Reply-To: <20091121195802.GC8502@parisc-linux.org>
On Sat, Nov 21, 2009 at 12:58:03PM -0700, Matthew Wilcox wrote:
> On Sat, Nov 21, 2009 at 05:13:56AM -0500, Christoph Hellwig wrote:
> > On Fri, Nov 20, 2009 at 09:45:21PM -0500, Martin K. Petersen wrote:
> > > The discard ioctl is used by mkfs utilities to clear a block device
> > > prior to putting metadata down. However, not all devices return zeroed
> > > blocks after a discard. Some drives return stale data, potentially
> > > containing old superblocks. It is therefore important to know whether
> > > discarded blocks are properly zeroed.
> >
> > At least for mkfs.xfs we make sure to still zero the important areas
> > after the TRIM ioctl anyway.
>
> Could you change that to zero _before_ the TRIM?
I could easily, but it would be a very bad idea.
next prev parent reply other threads:[~2009-11-23 17:05 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-11-21 2:45 Thin provisioning fixes Martin K. Petersen
2009-11-21 2:45 ` [PATCH 1/4] block: Allow devices to indicate whether discarded blocks are zeroed Martin K. Petersen
2009-11-21 10:13 ` Christoph Hellwig
2009-11-21 19:58 ` Matthew Wilcox
2009-11-22 2:43 ` Mark Lord
2009-11-23 16:37 ` Ric Wheeler
2009-11-23 16:54 ` Greg Freemyer
2009-11-23 17:02 ` Ric Wheeler
2009-11-23 17:03 ` Christoph Hellwig
2009-11-23 17:50 ` Eric Sandeen
2009-11-23 17:05 ` Christoph Hellwig [this message]
2009-11-21 12:50 ` Ric Wheeler
2009-11-21 20:17 ` Martin K. Petersen
2009-11-21 2:45 ` [PATCH 2/4] sd: WRITE SAME(16) / UNMAP support Martin K. Petersen
2009-11-21 2:45 ` [PATCH 3/4] libata: Report zeroed read after Trim and max discard size Martin K. Petersen
2009-11-21 10:49 ` Christoph Hellwig
2009-11-21 20:16 ` Martin K. Petersen
2009-11-24 14:35 ` Christoph Hellwig
2009-11-24 15:20 ` Mark Lord
2009-11-24 15:21 ` Christoph Hellwig
2009-11-21 2:45 ` [PATCH 4/4] libata: Fix garbled Trim payload Martin K. Petersen
2009-11-21 10:47 ` Christoph Hellwig
2009-11-21 19:50 ` Martin K. Petersen
2009-11-21 4:56 ` Thin provisioning fixes Eric Sandeen
2009-11-21 6:08 ` Martin K. Petersen
2009-11-21 6:55 ` Martin K. Petersen
2009-11-26 10:59 ` Christoph Hellwig
2009-11-26 11:01 ` Jens Axboe
2009-11-26 11:05 ` Christoph Hellwig
2009-11-26 15:13 ` Mark Lord
2009-11-26 15:14 ` Mark Lord
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