From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932097Ab1ISGcn (ORCPT ); Mon, 19 Sep 2011 02:32:43 -0400 Received: from ipmail07.adl2.internode.on.net ([150.101.137.131]:24909 "EHLO ipmail07.adl2.internode.on.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751152Ab1ISGcm (ORCPT ); Mon, 19 Sep 2011 02:32:42 -0400 X-IronPort-Anti-Spam-Filtered: true X-IronPort-Anti-Spam-Result: Av0EACrfdk55LAXJ/2dsb2JhbABCpzp4gVMBAQUyASMjEAgDDgouFCUDIRO8Ug6GagScGYhv Date: Mon, 19 Sep 2011 16:32:26 +1000 From: Dave Chinner To: Michael Kerrisk Cc: Josef Bacik , linux-man@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, Lucian Adrian Grijincu , Al Viro , Dave Chinner Subject: Re: [PATCH] fallocate.2: add FALLOC_FL_PUNCH_HOLE flag definition Message-ID: <20110919063226.GI15688@dastard> References: <1289840876-3546-1-git-send-email-josef@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Sep 19, 2011 at 07:08:17AM +0200, Michael Kerrisk wrote: > Hi Josef (Dave C, please also note comments below), > > On Mon, Nov 15, 2010 at 6:07 PM, Josef Bacik wrote: > > This patch adds the relevant documenation for using fallocate with the > > FALLOC_FL_PUNCH_HOLE mode.  This information comes from the implementation of > > FALLOC_FL_PUNCH_HOLE that I've posted along with this man page update to outline > > the definition for hole punching.  Obviously this patch is dependant upon the > > current implementation being accepted.  Thanks, > > > > Signed-off-by: Josef Bacik > > --- > >  man2/fallocate.2 |   15 ++++++++++++--- > >  1 files changed, 12 insertions(+), 3 deletions(-) > > > > diff --git a/man2/fallocate.2 b/man2/fallocate.2 > > index 42eefbd..1b28916 100644 > > --- a/man2/fallocate.2 > > +++ b/man2/fallocate.2 > > @@ -31,9 +31,8 @@ bytes. > > > >  The > >  .I mode > > -argument determines the operation to be performed on the given range. > > -Currently only one flag is supported for > > -.IR mode : > > +argument determines the operation to be performed on the given range, the > > +value can be one of the following: > >  .TP > >  .B FALLOC_FL_KEEP_SIZE > >  This flag allocates and initializes to zero the disk space > > @@ -50,6 +49,16 @@ the file size (as reported by > >  .BR stat (2)) > >  even if it is less than > >  .IR offset + len . > > +.TP > > +.B FALLOC_FL_PUNCH_HOLE > > +This flag de-allocates the disk space within the range specified by > > +.I offset > > +and > > +.IR len . > > +This call preserves the file size (as reported by > > +.BR stat (2)), > > +the only change will be to the amount of space used by the file.  After a > > +successful call, subsequent reads from this range will return 0's. > >  .\" > >  .\" Note from Amit Arora: > >  .\" There were few more flags which were discussed, but none of > > -- > > 1.6.6.1 > > Thanks for this patch. As noted in another mail, Lucian also sent a > patch for FALLOC_FL_PUNCH_HOLE, and I applied his patch first, and > then added some pieces from yours, as well as some of my own edits. > > However, the addition of a second class of operation to the man page > made it clear that some significant restructuring of the page is > required. So I substantially reworked the page, including the > preexisting material on the default "file allocation" operation (Dave > C please note). > > Josef, Lucian, could I ask you to check ("man -l ") the final > text (below) for FALLOC_FL_PUNCH_HOLE (including the EPERM error under > ERRORS)? > > Dave, could I ask you to review my reworked text for the "Allocating > disk space" subsection? Looks OK to me. Cheers, Dave. -- Dave Chinner david@fromorbit.com