From: Christoph Hellwig <hch@infradead.org>
To: Douglas Gilbert <dgilbert@interlog.com>
Cc: linux-scsi@vger.kernel.org, linux-ide@vger.kernel.org,
linux-kernel@vger.kernel.org, liml@rtr.ca, jens.axboe@oracle.com,
matthew@wil.cx, dwmw2@infradead.org
Subject: Re: [PATCH 4/7] sd: add support for WRITE SAME (16) with unmap bit
Date: Sat, 29 Aug 2009 22:48:45 -0400 [thread overview]
Message-ID: <20090830024845.GA8095@infradead.org> (raw)
In-Reply-To: <4A99E760.1060302@interlog.com>
On Sat, Aug 29, 2009 at 10:43:44PM -0400, Douglas Gilbert wrote:
>> Filesystems do not care if these blocks are in a defined state, as
>> they must never return the content of uninitilized blocks to userspace.
>> Now if we do want to support discard through raid arrays we might start
>> to care, and will have check the TPRZ bit.
>
> Another reason to note the TPRZ bit is that if it is 1 then
> the data given to WRITE SAME (16 and 32) must be a logical
> block of zeros for the UNMAP bit to be honoured (sbc3r19.pdf
> section 4.6.3.2 last paragraph).
Ah, good hint. I did in fact send down ZERO_PAGE(0) in an earlier
version, but the bio completion handler wasn't too happy with that
anymore after adding Willy's patch to free the page there. I'll
either need to tweak it to make that conditional or zero the page
we allocated.
next prev parent reply other threads:[~2009-08-30 2:48 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-08-29 23:03 [PATCH 0/7] discard support revisited Christoph Hellwig
2009-08-29 23:03 ` [PATCH 1/7] Make DISCARD_BARRIER and DISCARD_NOBARRIER writes instead of reads Christoph Hellwig
2009-09-03 17:52 ` David Woodhouse
2009-09-03 17:56 ` Matthew Wilcox
2009-08-29 23:03 ` [PATCH 2/7] block: use blkdev_issue_discard in blk_ioctl_discard Christoph Hellwig
2009-09-01 9:06 ` Steven Whitehouse
2009-09-11 22:26 ` Christoph Hellwig
2009-09-14 9:40 ` Jens Axboe
2009-08-29 23:03 ` [PATCH 3/7] block: discard may need to allocate pages Christoph Hellwig
2009-08-29 23:03 ` [PATCH 4/7] sd: add support for WRITE SAME (16) with unmap bit Christoph Hellwig
2009-08-30 0:43 ` Douglas Gilbert
2009-08-30 1:05 ` Christoph Hellwig
2009-08-30 2:43 ` Douglas Gilbert
2009-08-30 2:48 ` Christoph Hellwig [this message]
2009-08-30 11:12 ` Sergei Shtylyov
2009-08-30 17:14 ` Christoph Hellwig
2009-08-29 23:03 ` [PATCH 5/7] libata: Add support for TRIM Christoph Hellwig
2009-08-29 23:03 ` [PATCH 6/7] block: allow large discard requests Christoph Hellwig
2009-08-30 2:49 ` Mark Lord
2009-08-30 2:50 ` Matthew Wilcox
2009-08-30 2:52 ` Mark Lord
2009-08-30 2:56 ` Christoph Hellwig
2009-08-29 23:03 ` [PATCH 7/7] xfs: add batches discard support Christoph Hellwig
2009-08-29 23:37 ` [PATCH 0/7] discard support revisited Matthew Wilcox
2009-08-30 2:15 ` Christoph Hellwig
2009-08-30 3:03 ` Matthew Wilcox
2009-08-30 20:17 ` James Bottomley
2009-08-30 21:42 ` Matthew Wilcox
2009-08-30 22:48 ` Christoph Hellwig
2009-09-02 19:46 ` Matthew Wilcox
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