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From: Milan Broz <gmazyland@gmail.com>
To: ".. ink .." <mhogomchungu@gmail.com>,
	"dm-crypt@saout.de" <dm-crypt@saout.de>
Subject: Re: [dm-crypt] Alignment issue with 4K disk
Date: Sat, 9 Jan 2016 13:30:37 +0100	[thread overview]
Message-ID: <5690FD6D.4050605@gmail.com> (raw)
In-Reply-To: <CAFnMBaQLwTbFeeVJn-XR2eKRLy4jJb8-hFrrm02AzoGqkEOFTw@mail.gmail.com>



On 01/07/2016 07:00 PM, .. ink .. wrote:
> There is another (i think) related problem that was reported here[1]
> 
> Are these warnings serious or can they be ignored?
> 
> 
> [1] https://github.com/mhogomchungu/zuluCrypt/issues/25

If I read this correctly, it s caused by mapping of an unaligned plaintext device-mapper
device (unlocked VeraCrypt) to underlying partition.

That's a bug (or lack of proper alignment) inside VeraCrypt header or in GPT partitioning
- it should respect underlying device alignment while creating device/partition.

Anyway, I think the only consequence should be performance drop, it should still work.

Note that output from GPT says 512B while dm kernel message says 4k block... GPT should
use 4k block as well.
Reporter should paste output of "lsblk -t" with device activated to check what underlying
device report alignment limits are violated in storage stack).

We cannot do anything with it I guess, cryptsetup just activates what is written inside
Veracrypt header using alignment limits reported by kernel.

Milan

  reply	other threads:[~2016-01-09 12:30 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-01-04 21:31 [dm-crypt] Alignment issue with 4K disk Yves-Alexis Perez
2016-01-04 21:54 ` Sven Eschenberg
2016-01-04 22:20   ` Yves-Alexis Perez
2016-01-04 22:41     ` Sven Eschenberg
2016-01-04 23:02     ` Sven Eschenberg
2016-01-05 10:14       ` Yves-Alexis Perez
2016-01-07 18:00         ` .. ink ..
2016-01-09 12:30           ` Milan Broz [this message]
2016-01-09 14:47             ` Sven Eschenberg
2016-01-10  0:25 Eugen Rogoza
2016-01-10  1:14 ` Sven Eschenberg
2016-01-10  4:30   ` Sven Eschenberg
2016-01-10 15:18 Eugen Rogoza
2016-01-10 15:37 Eugen Rogoza
2016-01-10 17:22 Eugen Rogoza
2016-01-10 19:13 ` Sven Eschenberg
2016-01-10 20:20   ` Eugen Rogoza
2016-01-10 21:00     ` Sven Eschenberg

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