From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from relay.sgi.com (relay3.corp.sgi.com [198.149.34.15]) by oss.sgi.com (8.14.3/8.14.3/SuSE Linux 0.8) with ESMTP id q0CHe2ZH009038 for ; Thu, 12 Jan 2012 11:40:03 -0600 Date: Thu, 12 Jan 2012 11:39:59 -0600 From: Ben Myers Subject: Re: Introduce SEEK_DATA/SEEK_HOLE to XFS V5 Message-ID: <20120112173959.GU20739@sgi.com> References: <4F06F71A.2010301@oracle.com> <20120110171855.GX6390@sgi.com> <4F0D21E5.7010908@oracle.com> <4F0DFB20.7030704@sgi.com> <4F0EE5B6.2040408@oracle.com> <4F0EF5DC.1070207@sgi.com> <20120112164148.GB22223@infradead.org> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20120112164148.GB22223@infradead.org> List-Id: XFS Filesystem from SGI List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: xfs-bounces@oss.sgi.com Errors-To: xfs-bounces@oss.sgi.com To: Christoph Hellwig Cc: jeff.liu@oracle.com, Mark Tinguely , Chris Mason , xfs@oss.sgi.com On Thu, Jan 12, 2012 at 11:41:48AM -0500, Christoph Hellwig wrote: > On Thu, Jan 12, 2012 at 09:01:48AM -0600, Mark Tinguely wrote: > > >Sorry, am was well understood your opinions in this point for now. > > >IMHO, we can only find and return the data buffer offset at a dirty or > > >unwritten page once the first page was probed. > > > > > > > From my tests, xfs_bmapi_read() can only find holes if they cross or > > start on a 64KB boundary. It would be nice if unwritten extents were > > at least that good at finding holes. > > Are you testing on ia64 with 64k blocks? :) xfs_bmapi_read will > find holes down to block granularity, that's how it's implemented. > However recent XFS does fairly aggressive preallocation, so you probably ^^^^ it is speculative delay in this case, I think. -Ben > won't find small holes unless you explicitly punch them out using > XFS_IOC_UNRESVSP or fallocate with the hole punch flag. _______________________________________________ xfs mailing list xfs@oss.sgi.com http://oss.sgi.com/mailman/listinfo/xfs