From: Andreas Dilger Subject: Re: [PATCH 4/7][TAKE5] support new modes in fallocate Date: Mon, 25 Jun 2007 15:52:39 -0600 Message-ID: <20070625215239.GK5181@schatzie.adilger.int> References: <20070510223950.GD86004887@sgi.com> <20070511110301.GB28425@in.ibm.com> <20070512080157.GF85884050@sgi.com> <20070612061652.GA6320@amitarora.in.ibm.com> <20070613235217.GS86004887@sgi.com> <20070614091458.GH5181@schatzie.adilger.int> <20070614120413.GD86004887@sgi.com> <20070614193347.GN5181@schatzie.adilger.int> <20070625132810.GA1951@amitarora.in.ibm.com> <20070625134500.GE1951@amitarora.in.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, linux-ext4@vger.kernel.org, David Chinner , suparna@in.ibm.com, cmm@us.ibm.com, xfs@oss.sgi.com To: "Amit K. Arora" Return-path: Content-Disposition: inline In-Reply-To: <20070625134500.GE1951@amitarora.in.ibm.com> Sender: linux-kernel-owner@vger.kernel.org List-Id: linux-ext4.vger.kernel.org On Jun 25, 2007 19:15 +0530, Amit K. Arora wrote: > +#define FA_FL_DEALLOC 0x01 /* default is allocate */ > +#define FA_FL_KEEP_SIZE 0x02 /* default is extend/shrink size */ > +#define FA_FL_DEL_DATA 0x04 /* default is keep written data on DEALLOC */ In XFS one of the (many) ALLOC modes is to zero existing data on allocate. For ext4 all this would mean is calling ext4_ext_mark_uninitialized() on each extent. For some workloads this would be much faster than truncate and reallocate of all the blocks in a file. In that light, please change the comment to /* default is keep existing data */ so that it doesn't imply this is only for DEALLOC. Cheers, Andreas -- Andreas Dilger Principal Software Engineer Cluster File Systems, Inc.