linux-ext4 - Re: flashing large eMMC partitions with ext4

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite for Android: free password hash cracker in your pocket

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <419A2628-5AF6-4B32-85B8-BE1E2B159DFA@gmail.com>
Date:	Fri, 22 Jul 2011 10:35:20 -0600
From:	Andreas Dilger <aedilger@...il.com>
To:	Round Robinjp <roundrobinjp@...oo.co.jp>
Cc:	"linux-ext4@...r.kernel.org" <linux-ext4@...r.kernel.org>
Subject: Re: flashing large eMMC partitions with ext4

If you can wipe the MMC device to be all-zero efficiently, then you can format it quickly with "mke2fs -E lazy_itable_init,lazy_journal_init ..." and restore from a tarball.

Alternately, Lukas recently added support for QCOW2 sparse image format, and it should be possible to restore this to the device efficiently, if it is zeroed in advance. I don't know if his code skips all-zero blocks in the image, but that should be possible to add fairly easily. 

Cheers, Andreas

On 2011-07-22, at 9:49 AM, Round Robinjp <roundrobinjp@...oo.co.jp> wrote:

> Hi
> 
> I have a question regarding making ext4 image for
> large eMMC partition.
> 
> We have a 4G partition in our embedded device
> in which we want to use ext4 filesystem.
> But for that we have to create a 4G image.
> flashing this 4G image to the eMMC takes a long
> time. Is there any way to reduce this time?
> 
> For vfat, you can truncate the image leaving only
> non zero-filled blocks which makes the image very
> short and the time for flashing is reduced.
> Is something similar to that possible for ext4?
> 
> Thanks
> Robin
> --
> To unsubscribe from this list: send the line "unsubscribe linux-ext4" in
> the body of a message to majordomo@...r.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html
--
To unsubscribe from this list: send the line "unsubscribe linux-ext4" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html