From: Eric Sandeen <sandeen@redhat.com>
To: Dmitry Monakhov <dmonakhov@openvz.org>
Cc: "Bo Brantén" <bosse@acc.umu.se>, linux-ext4@vger.kernel.org
Subject: Re: persistent preallocation
Date: Tue, 03 Aug 2010 11:25:57 -0500 [thread overview]
Message-ID: <4C584315.6060701@redhat.com> (raw)
In-Reply-To: <87aap4aqrf.fsf@dmon-lap.sw.ru>
On 08/03/2010 06:18 AM, Dmitry Monakhov wrote:
> Bo Brantén <bosse@acc.umu.se> writes:
>
>> Hello,
>>
>> I have a question on the implementation of persistent preallocation,
>> the reason to not return the disk block is because it can contain old
>> data but I wonder if an implementation has to return zeros instead or
> Please look at fallocate(2) syscall.
>> if it could return any garbage as long as it is not _that_ garbage?
> Off course it is not a garbage, it is old user's data which may be
> very very useful (old passwords, cookies, and etc)for person who has
> time to analyze it :)
I think the question was, could the implementation return 0xFF rather
than what is actually on disk (and rather than 0's) when reading a
preallocated block.
You could certainly write it that way, but I don't know why you would
want to...
IOW it wouldn't be posix_fallocate() or fallocate(), it'd be
junk_preallocate() or something.
-Eric
>>
>> Bo Branten
>>
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next prev parent reply other threads:[~2010-08-03 16:26 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-08-03 10:58 persistent preallocation Bo Brantén
2010-08-03 11:18 ` Dmitry Monakhov
2010-08-03 16:25 ` Eric Sandeen [this message]
2010-08-03 18:06 ` Ted Ts'o
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