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From: Spelic <spelic@shiftmail.org>
To: device-mapper development <dm-devel@redhat.com>
Subject: Re: dm-integrity: integrity protection device-mapper target
Date: Wed, 23 Jan 2013 10:15:09 +0100	[thread overview]
Message-ID: <50FFAA1D.8090402@shiftmail.org> (raw)
In-Reply-To: <Pine.LNX.4.64.1301221928350.21650@file.rdu.redhat.com>

On 01/23/13 02:29, Mikulas Patocka wrote:
> I am thinking about possibly rewriting it so that it has two hashes 
> per sector so that if either old or new data is read, at least one 
> hash matches and it won't result in data corruption. Mikulas 

Seems like a great idea, but have you thought that for it to work the 
new hash block has to be written before the new data block?

A naiive implementation would send a stream of flush requests and 
completely screw up the disk write cache...

It would be great if Linux could use ordered SCSI commands (that would 
be a feature of the disk but only of SCSI ones AFAIK, correct me if I am 
wrong) or had threaded I/O commands (that could be a feature of the 
elevator methinks) so implement dependencies among write commands and 
not completely screw up the disk cache like above. Is there any plan to 
do that?

  parent reply	other threads:[~2013-01-23  9:15 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-01-17  4:54 dm-integrity: integrity protection device-mapper target Mikulas Patocka
2013-01-18 21:43 ` Kasatkin, Dmitry
2013-01-18 23:16   ` Alasdair G Kergon
2013-01-18 23:58     ` Kasatkin, Dmitry
2013-01-21 13:51       ` Alan Cox
2013-01-21 13:51         ` Alan Cox
2013-01-21 10:37     ` Kasatkin, Dmitry
2013-01-21 10:38     ` Kasatkin, Dmitry
2013-01-23  1:29   ` Mikulas Patocka
2013-01-23  6:09     ` [dm-devel] " Will Drewry
2013-01-23 10:20       ` Kasatkin, Dmitry
2013-01-28  1:43         ` Will Drewry
2013-01-23  9:15     ` Spelic [this message]
2013-01-23 10:19     ` Kasatkin, Dmitry
2013-01-23 10:19       ` Kasatkin, Dmitry

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