From: Eric Sandeen <sandeen@redhat.com>
To: Dave Young <hidave.darkstar@gmail.com>
Cc: Josef Bacik <josef@redhat.com>, Theodore Tso <tytso@mit.edu>,
linux-ext4@vger.kernel.org,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: ext2/3/4: punch support?
Date: Mon, 28 Feb 2011 09:17:54 -0600 [thread overview]
Message-ID: <4D6BBCA2.8030104@redhat.com> (raw)
In-Reply-To: <AANLkTimwpoi6agwO4q8qhOcohhSnYFrKhFOCnk0BuTEC@mail.gmail.com>
On 2/28/11 8:29 AM, Dave Young wrote:
> On Mon, Feb 28, 2011 at 9:11 PM, Josef Bacik <josef@redhat.com> wrote:
>> On Mon, Feb 28, 2011 at 03:03:40PM +0800, Dave Young wrote:
>>> Hi, josef and ext guys
>>>
>>> Do you have any plan with ext4 hole punching support? And the
>>> fallocate for ext2/3?
>>>
>>> What's the obstacle to work on this? could someone tell the status of
>>> this issue?
>>
>> There is no obstacle, just nobody has bothered to do it. If you want to do it
>> go for it. Thanks,
>
> Yes, I want to do some kvm image space discard stuff,
> I use ext4 as my filesystem, but currently only xfs support something
> like trim/discard.
As Lukas said, ext4 & ext3 support various forms of trim/discard already.
But that's different from punch...
And as for fallocate on ext3, you need somewhere to put the metadata to indicate a block is allocated but not written. This was a lot more straightforward for ext4, since it describes a large range of blocks with a single extent structure.
-Eric
> I know general knowledge about ext filesystem, but nearly new to ext4 code,
> could you give some hint where to start?
>
> --
> Thanks
> dave
> --
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next prev parent reply other threads:[~2011-02-28 15:17 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-02-28 7:03 ext2/3/4: punch support? Dave Young
2011-02-28 13:11 ` Josef Bacik
2011-02-28 14:29 ` Dave Young
2011-02-28 14:50 ` Lukas Czerner
2011-02-28 15:17 ` Eric Sandeen [this message]
2011-03-01 1:27 ` Dave Young
[not found] ` <OFF2910C77.5B46C8B2-ON87257846.000354EE-07257846.000414E9@us.ibm.com>
2011-03-01 1:32 ` Dave Young
2011-03-01 2:19 ` Allison Henderson
2011-03-01 2:26 ` Dave Young
2011-03-01 3:12 ` Allison Henderson
-- strict thread matches above, loose matches on Subject: below --
2011-03-01 0:59 Allison Henderson
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