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From: Milan Broz <mbroz@redhat.com>
To: Mike Snitzer <snitzer@redhat.com>
Cc: "Martin K. Petersen" <martin.petersen@oracle.com>,
	Joseph Salisbury <joseph.salisbury@canonical.com>,
	Kernel Team <kernel-team@lists.ubuntu.com>,
	linux-kernel@vger.kernel.org, jgarzik@redhat.com,
	JBottomley@Parallels.com
Subject: Re: [v3.7 Regression]  [SCSI] sd: Implement support for WRITE SAME
Date: Wed, 19 Dec 2012 21:45:26 +0100	[thread overview]
Message-ID: <50D22766.9090107@redhat.com> (raw)
In-Reply-To: <20121219195801.GA14456@redhat.com>

On 12/19/2012 08:58 PM, Mike Snitzer wrote:
> On Wed, Dec 19 2012 at 11:58am -0500,
> Martin K. Petersen <martin.petersen@oracle.com> wrote:
> 
>>>>>>> "Joseph" == Joseph Salisbury <joseph.salisbury@canonical.com> writes:
>>
>> Joseph> I captured the netconsole output from boot until I reproduced
>> Joseph> the bug. The RIP points to kcryptd_crypt_write_io_submit() in
>> Joseph> ~/drivers/md/dm-crypt.c.  The output can be seen at:
>>
>> I'm thinking that dm-crypt should probably set max_write_same_sectors to
>> 0. It doesn't really make much sense for a crypto driver to pass that
>> command through.

IMHO WRITE_SAME doesn't not make sense in encrypted storage. The same sectors
in plaintext are _not_ the same in ciphertext. NEVER.
(If so, you have a security problem.)

It must be disabled in dmcrypt explicitly then (max_write_same_sectors?).

Is it only dmcrypt, or encrypted fs are affected too?

Milan


  parent reply	other threads:[~2012-12-19 20:45 UTC|newest]

Thread overview: 22+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-12-14 20:30 [v3.7 Regression] [SCSI] sd: Implement support for WRITE SAME Joseph Salisbury
2012-12-14 21:11 ` Mike Snitzer
2012-12-15  2:38   ` Joseph Salisbury
2012-12-14 22:35 ` Martin K. Petersen
2012-12-15  2:40   ` Joseph Salisbury
2012-12-18 19:52   ` Joseph Salisbury
2012-12-19 16:58     ` Martin K. Petersen
2012-12-19 19:58       ` Mike Snitzer
2012-12-19 19:59         ` Joseph Salisbury
2012-12-19 20:45           ` Martin K. Petersen
2012-12-19 20:45         ` Martin K. Petersen
2012-12-19 20:45         ` Milan Broz [this message]
2012-12-19 21:07           ` [PATCH] dm-crypt: never use write same (was Re: [v3.7 Regression] [SCSI] sd: Implement support for WRITE SAME) Milan Broz
2012-12-19 21:07             ` Joseph Salisbury
2012-12-19 22:20             ` Joseph Salisbury
2012-12-19 22:23               ` Milan Broz
2015-07-13 16:33               ` Joseph Salisbury
2015-07-13 16:59                 ` Milan Broz
2015-07-13 17:01                 ` Milan Broz
2015-07-13 18:01                   ` Mike Snitzer
2012-12-20  0:11             ` [PATCH] " Martin K. Petersen
2012-12-20  5:47               ` Mike Snitzer

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