From mboxrd@z Thu Jan 1 00:00:00 1970 From: Al Viro Subject: Re: [patch 4/8] fs, exportfs: Add export_encode_inode_fh helper Date: Thu, 16 Aug 2012 15:41:52 +0100 Message-ID: <20120816144152.GT23464@ZenIV.linux.org.uk> References: <20120815210237.GF25421@moon> <20120815220622.GA28054@fieldses.org> <20120816062448.GA32081@moon> <20120816123814.GD1209@moon> <20120816134339.GQ23464@ZenIV.linux.org.uk> <502CF9DA.8030701@parallels.com> <20120816135019.GS23464@ZenIV.linux.org.uk> <20120816135448.GP32081@moon> <1345125779.3259.50.camel@dabdike.int.hansenpartnership.com> <20120816141553.GF1209@moon> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: James Bottomley , Pavel Emelianov , "J. Bruce Fields" , "linux-kernel@vger.kernel.org" , "linux-fsdevel@vger.kernel.org" , Alexey Dobriyan , Andrew Morton , Matthew Helsley To: Cyrill Gorcunov Return-path: Content-Disposition: inline In-Reply-To: <20120816141553.GF1209@moon> Sender: linux-kernel-owner@vger.kernel.org List-Id: linux-fsdevel.vger.kernel.org On Thu, Aug 16, 2012 at 06:15:53PM +0400, Cyrill Gorcunov wrote: > On Thu, Aug 16, 2012 at 02:03:00PM +0000, James Bottomley wrote: > > > > What's wrong with saying "we don't support idiotify"? > > > > > > Al, we need some way to restore inotifies after checkpoint. > > > At the very early versions of these patches I simply added > > > dentry to the inotify mark thus once inotify created we always > > > have a dentry to refer on in encode_fh, but I'm not sure if > > > this will be good design. > > > > Actually, I was about to suggest this. This can be done internally > > within fs/notify without actually modifying the syscall interface, can't > > it, since they take a path which is used to obtain the inode? It looks > > like the whole of the inotify interface could be internally recast to > > use dentries instead of inodes. Unless I've missed something obvious? > > Well, after looking into do_sys_name_to_handle->exportfs_encode_fh > sequence more precisely it seems it will be easier to extend > exportfs_encode_fh to support inodes directly instead of playing > with notify code (again, if i'm not missing something too). > i'm cooking a patch to show (once it's tested i'll send it out). Good luck doing that with e.g. VFAT... And then there's such thing as filesystems that don't have ->encode_fh() for a lot of very good reasons; just try to do that on sysfs, for example. Or on ramfs, for that matter... And while saying "you can't export that over NFS" seems to work fine, idiotify-lovers will screech if you try to ban their perversion of choice on those filesystems.