From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from cuda.sgi.com (cuda1.sgi.com [192.48.157.11]) by oss.sgi.com (8.14.3/8.14.3/SuSE Linux 0.8) with ESMTP id q39MiL6h221628 for ; Mon, 9 Apr 2012 17:44:21 -0500 Received: from ipmail06.adl6.internode.on.net (ipmail06.adl6.internode.on.net [150.101.137.145]) by cuda.sgi.com with ESMTP id 9E3NWbLKLaf32nGK for ; Mon, 09 Apr 2012 15:44:19 -0700 (PDT) Date: Tue, 10 Apr 2012 08:44:16 +1000 From: Dave Chinner Subject: Re: detecting case-insensitivity Message-ID: <20120409224416.GM18323@dastard> References: <20120409212833.GA10508@fieldses.org> <20120409221946.GL18323@dastard> <20120409222720.GB10508@fieldses.org> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20120409222720.GB10508@fieldses.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: "J. Bruce Fields" Cc: Vyacheslav Dubeyko , xfs@oss.sgi.com On Mon, Apr 09, 2012 at 06:27:20PM -0400, J. Bruce Fields wrote: > On Tue, Apr 10, 2012 at 08:19:46AM +1000, Dave Chinner wrote: > > On Mon, Apr 09, 2012 at 05:28:33PM -0400, J. Bruce Fields wrote: > > > > > From: Dave Chinner > > > > > Date: 09.04.2012 03.30 > > > > > > > > > > On Sat, Apr 07, 2012 at 10:00:29AM -0400, J. Bruce Fields wrote: > > > > > > Is there a generic way to detect whether a given filesystem is > > > > > > case-insensitive? If not, how should it be done? (A bit in s_flags?) > > > > > > > > > > I don't think there is a generic flag for it. We could trivially add > > > > > one, I think, as it is generally a fixed property for the entire > > > > > filesystem.... > > > > > > So, I assume the following is totally wrong, but the basic idea (create > > > a new flag, set it based on xfs_sb_version_hasasciici, check it in nfsd) > > > would work? > > > > Looks mostly OK to me. > > > > > On Mon, Apr 09, 2012 at 09:01:11AM +0400, Vyacheslav Dubeyko wrote: > > > > But why does it need to detect that filesystem case-insensitive or not? In what use-case does it need to make such detection? > > > > > > To be honest, I have no idea--it's not a mandatory attribute, so I think > > > I'll instead just ceasing to support the attribute and seeing if anyone > > > complains.... > > > > I suspect that there are some applications out there that might care > > that Bruce and bruce are the same file for matching purposes (e.g. a > > file manager) > > I suppose they could try the create and find out what happens. > > If they actually want to be able to predict collisions instead of > recognizing them after the fact then they may need to know in more > detail how we handle case, and then I worry that I'll have to start > understanding what language like this means: > > http://tools.ietf.org/html/draft-ietf-nfsv4-rfc3530bis-17#section-12.7.1.3 > > ...if the NFSv4 file server supports the case_insensitive file > system attribute, and if the case_insensitive attribute is true > for a given file system, the NFS version 4 server MUST use the > Unicode case mapping tables for the version of Unicode > corresponding to the character repertoire. > > which isn't high on my todo list. Right, unicode CI is a bitch to handle. There's still a lot of work to be done in XFS before that is supported. See: http://xfs.org/index.php/Unfinished_work#Support_for_unicode_.2F_utf8_filesystems So if the NFSv4 flag really means full unicode CI, then there's still work at the XFS level to be able to support that. ASCII CI is a walk in the park compared to unicode.... Cheers, Dave. -- Dave Chinner david@fromorbit.com _______________________________________________ xfs mailing list xfs@oss.sgi.com http://oss.sgi.com/mailman/listinfo/xfs