From mboxrd@z Thu Jan 1 00:00:00 1970 From: ebiederm@xmission.com (Eric W. Biederman) Subject: Re: [patch 4/8] fs, exportfs: Add export_encode_inode_fh helper Date: Fri, 17 Aug 2012 13:58:31 -0700 Message-ID: <87r4r5z154.fsf@xmission.com> 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> <20120816144152.GT23464@ZenIV.linux.org.uk> Mime-Version: 1.0 Content-Type: text/plain Cc: Cyrill Gorcunov , James Bottomley , Pavel Emelianov , "J. Bruce Fields" , "linux-kernel\@vger.kernel.org" , "linux-fsdevel\@vger.kernel.org" , Alexey Dobriyan , Andrew Morton , Matthew Helsley To: Al Viro Return-path: Received: from out03.mta.xmission.com ([166.70.13.233]:34781 "EHLO out03.mta.xmission.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753452Ab2HQU6m (ORCPT ); Fri, 17 Aug 2012 16:58:42 -0400 In-Reply-To: <20120816144152.GT23464@ZenIV.linux.org.uk> (Al Viro's message of "Thu, 16 Aug 2012 15:41:52 +0100") Sender: linux-fsdevel-owner@vger.kernel.org List-ID: Al Viro writes: > 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. For whatever it is worth inotify does not currently work on sysfs or procfs or any other filesystem that looks like a network filesystem and whose modifications don't proceed through the vfs like a normal filesystem. Eric