From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jamie Lokier Subject: Re: silent semantic changes with reiser4 Date: Thu, 26 Aug 2004 13:12:23 +0100 Message-ID: <20040826121223.GG30449@mail.shareable.org> References: <200408261034.38509.vda@port.imtp.ilyichevsk.odessa.ua> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Denis Vlasenko , Matt Mackall , Nicholas Miell , Wichert Akkerman , Jeremy Allison , Andrew Morton , Spam , torvalds@osdl.org, reiser@namesys.com, hch@lst.de, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, flx@namesys.com, reiserfs-list@namesys.com Return-path: list-help: list-unsubscribe: list-post: Errors-To: flx@namesys.com To: Rik van Riel Content-Disposition: inline In-Reply-To: List-Id: linux-fsdevel.vger.kernel.org Rik van Riel wrote: > > cat b does not preserve following file properties even on standard > > UNIX filesystems: name,owner,group,permissions. > > Losing permissions is one thing. Annoying, mostly. I find losing mtime annoying. That's why I don't use Mozilla's download manager (and Navigator's before it) because they presumed that mtime isn't worth copying. ncftp and wget do the right thing, but it's annoying that I can't use the fancy tools and get the metadata _I_ want transferred by them. > However, actual losing file data during such a copy is > nothing short of a disaster, IMHO. Note that file-as-directory doesn't imply that you can store just anything into those directories. Is it a problem to decree that "file data MUST NOT be stored in a metadata directory; only non-essential metadata and data computed from the file data may be stored"? > In my opinion we shouldn't merge file-as-a-directory > semantics into the kernel until we figure out how to > fix the backup/restore problem and keep standard unix > utilities work. Same as xattrs, for data that should be stored. But, unlike xattrs, while permissions and C-source-encoding should be stored, some of this metadata should _not_ be stored when making an archive and perhaps not when making a backup either. Personally I wouldn't want an archive containing a file to save and restore recomputable metadata like cached, extracted-on-demand MP3 id tags and email headers-as-metadata. I'd rather they were recalculated when needed, implying a stronger guarantee about their relationship to the data from which they're extracted - and implying that a user program might not be allowed to set them to inconsistent values. -- Jamie