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  PHC 
Open Source and information security mailing list archives
Hash Suite: Windows password security audit tool. GUI, reports in PDF.
[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Date:	Wed, 2 Sep 2015 09:28:37 -0400
From:	Austin S Hemmelgarn <>
To:	Raymond Jennings <>,
	Albino B Neto <>
Cc:	Linus Torvalds <>,
	Jan Kara <>, LKML <>,
	"" <>,
	linux-fsdevel <>
Subject: Re: [GIT PULL] Ext3 removal, quota & udf fixes

On 2015-09-02 01:46, Raymond Jennings wrote:
> On 09/01/15 20:30, Albino B Neto wrote:
>> 2015-08-31 23:53 GMT-03:00 Theodore Ts'o <>:
>>> Yes, you can go back to ext3-only.  In fact, we do *not* automatically
>>> upgrade the file system to use ext4-specific features.
>>>> So it's not just a "you can use ext4 instead" issue. Can you do that
>>>> *without* then forcing an upgrade forever on that partition? I'm not
>>>> sure the ext4 people are really even willing to guarantee that kind of
>>>> backwards compatibility.
>>> Actually, we do guarantee this.  It's considered poor form to
>>> automatically change the superblock to add new file system features in
>>> a way that would break the ability for the user to roll back to an
>>> older kernel.  This isn't just for ext3->ext4, but for new ext4
>>> features such as metadata checksumming.  The user has to explicitly
>>> enable the feature using "tune2fs -O new_feature /dev/sdXX".
>> Yeah!
>> 2015-09-01 16:39 GMT-03:00 Austin S Hemmelgarn <>:
>>> NO, it is not logical.  A vast majority of Android smartphones in the
>>> wild
>>> use ext2, as do a very significant portion of embedded systems that
>>> don't
>>> have room for the few hundred kilobytes of extra code that the ext4
>>> driver
>>> has in comparison to ext2.
>> Ext2 portion embedded and Ext3 many machines.
> So basically the game plan is gutting ext3 because code-dupe with ext4,
> but keep ext2 because ext4 is too big for embedded to outright replace
> ext2?
> Hmm...are there any embedded systems out there that use ext3 and can fit
> its code ext3 but not ext4?
Probably, but I don't know of any myself.  TBH, the systems that use 
ext2 because of space savings are usually ones with less than 64M of 
RAM, which is becoming a smaller and smaller market share.

Download attachment "smime.p7s" of type "application/pkcs7-signature" (3019 bytes)

Powered by blists - more mailing lists