From: Frank Mayhar Subject: Re: Question on fallocate/ftruncate sequence (and flags) Date: Wed, 29 Jul 2009 08:59:22 -0700 Message-ID: <1248883162.16458.0.camel@bobble.smo.corp.google.com> References: <6601abe90907200936w61ebda92reae368a2b9efac66@mail.gmail.com> <4A64F37D.7020803@redhat.com> <1248211771.20743.2.camel@bobble.smo.corp.google.com> <20090721215421.GM4231@webber.adilger.int> <1248378517.8421.4.camel@bobble.smo.corp.google.com> <4A68C9EC.4050301@redhat.com> <1248382893.14764.8.camel@bobble.smo.corp.google.com> <20090729152923.GA25919@atrey.karlin.mff.cuni.cz> Mime-Version: 1.0 Content-Type: text/plain Content-Transfer-Encoding: 7bit Cc: Eric Sandeen , Andreas Dilger , Curt Wohlgemuth , ext4 development To: Jan Kara Return-path: Received: from smtp-out.google.com ([216.239.33.17]:21322 "EHLO smtp-out.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753091AbZG2QA7 (ORCPT ); Wed, 29 Jul 2009 12:00:59 -0400 In-Reply-To: <20090729152923.GA25919@atrey.karlin.mff.cuni.cz> Sender: linux-ext4-owner@vger.kernel.org List-ID: On Wed, 2009-07-29 at 17:29 +0200, Jan Kara wrote: > > On Thu, 2009-07-23 at 15:37 -0500, Eric Sandeen wrote: > > > As for: > > > > > > #define EXT4_EXT_MIGRATE 0x00100000 /* Inode is migrating */ > > > > > > this is not in the mask that FS_IOC_GETFLAGS can see ... and I don't > > > think anyone else uses FS_DIRECTIO_FL. > > > > > > I'm not sure if the flags not in FS_FL_USER_VISIBLE are supposed to be > > > fs-unique. > > > > The flag will need to be generic in any case, since inode_setattr() has > > to look at it when it's deciding whether or not to call vmtruncate(). > > Other filesystems that properly implement fallocate() may want to use it > > for this purpose as well. > Actually, Nick Piggin is changing the truncate path (the patches may > already be in Al Viro's tree) so that filesystem can come in earlier in > the truncate path and can make the decision when to truncate and when > not on its own. I guess this would help you... Yes, immensely, but it looks like that's a bit in the future... -- Frank Mayhar Google, Inc.