From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ben Myers Subject: Re: [PATCH 05/16] xfs: return the first match during case-insensitive lookup. Date: Tue, 14 Oct 2014 10:04:05 -0500 Message-ID: <20141014150405.GA2199@sgi.com> References: <20141003214758.GY1865@sgi.com> <20141003215542.GD1865@sgi.com> <20141006221928.GJ2301@dastard> <20141009154240.GC1865@sgi.com> <20141009203814.GB4376@dastard> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: linux-fsdevel@vger.kernel.org, olaf@sgi.com, xfs@oss.sgi.com To: Dave Chinner Return-path: Received: from relay2.sgi.com ([192.48.180.65]:48304 "EHLO relay.sgi.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S932409AbaJNPEK (ORCPT ); Tue, 14 Oct 2014 11:04:10 -0400 Content-Disposition: inline In-Reply-To: <20141009203814.GB4376@dastard> Sender: linux-fsdevel-owner@vger.kernel.org List-ID: Dave, On Fri, Oct 10, 2014 at 07:38:14AM +1100, Dave Chinner wrote: > On Thu, Oct 09, 2014 at 10:42:40AM -0500, Ben Myers wrote: > > On Tue, Oct 07, 2014 at 09:19:28AM +1100, Dave Chinner wrote: > > > On Fri, Oct 03, 2014 at 04:55:42PM -0500, Ben Myers wrote: > > > > From: Olaf Weber > > > > > > > > Change the XFS case-insensitive lookup code to return the first match > > > > found, even if it is not an exact match. Whether a filesystem uses > > > > case-insensitive lookups is determined by a superblock bit set during > > > > filesystem creation. This means that normal use cannot create two files > > > > that both match the same filename. > > > > > > > > Signed-off-by: Olaf Weber > > > > > > This is really dependent on whether we want to support mixed > > > CI/non-CI filesystems, yes? i.e. if we want to support mixed case > > > setups, then we need to keep the code as it stands? > > > > It depends upon what semantics you decide are correct in the mixed case. > > This is just one solution. > > Ok, so we need this code or somethign very similar to support mixed > case filesystems. Can you tell us what the other possible solutions > and semantics have been considered? There was some discussion of this in the v2 posting of this rfc. http://marc.info/?l=linux-xfs&m=141176024430150&w=2 Olaf's "readme" example at the above link is a pretty good example of what we're facing. And I don't have a good answer for which file to open. So for now we're just going for the cleanest solution. > > > What is the downside of keeping the code unchaged and our > > > options open? > > > > The code that is being removed here was for the case when you > > could have multiple filenames that match for a lookup, which was > > only possible when the ascii-ci bit was implemented as a mount > > option. > > Yes, I know what the code did - it allowed us to support mixed case > ascii-ci filesystems. All you've said is "if we remove mixed case > support the code is cleaner" but not addressed the issue at hand. I also tried to explain that as the codebase stands today, removal of this code does not represent a loss of functionality. It is dead code. > I'll try asking the same question a different way: if we keep this > code, will it work for mixed case unicode filesystem or do we have > to re-implement mixed case matching differently? If you definately want to keep this code around I'll look into this, but right now I don't have plans to extend the patchset to support mixed case insensitivity in a single filesystem. -Ben