From: Eric Sandeen Subject: Re: ext2/3/4: punch support? Date: Mon, 28 Feb 2011 09:17:54 -0600 Message-ID: <4D6BBCA2.8030104@redhat.com> References: <20110228131118.GA18193@dhcp231-156.rdu.redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Cc: Josef Bacik , Theodore Tso , linux-ext4@vger.kernel.org, Linux Kernel Mailing List To: Dave Young Return-path: In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org List-Id: linux-ext4.vger.kernel.org On 2/28/11 8:29 AM, Dave Young wrote: > On Mon, Feb 28, 2011 at 9:11 PM, Josef Bacik 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 > -- > To unsubscribe from this list: send the line "unsubscribe linux-ext4" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html