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From: Theodore Ts'o <tytso@mit.edu>
To: Dexuan Cui <decui@microsoft.com>
Cc: "linux-ext4@vger.kernel.org" <linux-ext4@vger.kernel.org>
Subject: Re: Is ext2 freezable?
Date: Thu, 18 Sep 2014 15:17:36 -0400	[thread overview]
Message-ID: <20140918191736.GC19520@thunk.org> (raw)
In-Reply-To: <EE124450C0AAF944A40DD71E61F878C99CE2C3@SINEX14MBXC418.southpacific.corp.microsoft.com>

On Thu, Sep 18, 2014 at 06:46:21AM +0000, Dexuan Cui wrote:
> 
> I've got the answer:
> ext2.ko itself does support fsfreeze, but typical linux distros don't supply
> ext2.ko at all now -- instead, they usually supply ext3.ko and have ext4 builtin.
> 
> So when I mount an ext2 partition, actually the kernel is registering the ext4
> driver as an ext2 driver and in this case the ext2's s_op->freeze_fs is NULL --
> but, why did ext4 choose this behavior for ext2?

It wasn't a deliberate design choice.  It was just that when
no-journal mode was added to ext4, freeeze support was never
implemented, and up until now, no one had asked for it.  We can add it
to ext4; thanks for calling it to our attention.

Cheers,

					- Ted

  reply	other threads:[~2014-09-18 19:17 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-09-18  6:46 Is ext2 freezable? Dexuan Cui
2014-09-18 19:17 ` Theodore Ts'o [this message]
2014-09-19  3:11   ` Dexuan Cui
2015-06-05 11:23     ` Syed Imtiaz
2015-06-05 16:47       ` Eric Sandeen
  -- strict thread matches above, loose matches on Subject: below --
2014-09-18  5:15 Dexuan Cui

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