Re: [patch 4/8] fs, exportfs: Add export_encode_inode_fh helper

From: "J. Bruce Fields" <bfields@fieldses.org>
To: Pavel Emelyanov <xemul@parallels.com>
Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>,
	Al Viro <viro@zeniv.linux.org.uk>,
	Cyrill Gorcunov <gorcunov@openvz.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"linux-fsdevel@vger.kernel.org" <linux-fsdevel@vger.kernel.org>,
	Alexey Dobriyan <adobriyan@gmail.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	James Bottomley <jbottomley@parallels.com>,
	Matthew Helsley <matt.helsley@gmail.com>
Subject: Re: [patch 4/8] fs, exportfs: Add export_encode_inode_fh helper
Date: Tue, 21 Aug 2012 08:11:55 -0400	[thread overview]
Message-ID: <20120821121155.GC9483@fieldses.org> (raw)
In-Reply-To: <50336C51.60501@parallels.com>

On Tue, Aug 21, 2012 at 03:09:05PM +0400, Pavel Emelyanov wrote:
> On 08/21/2012 02:54 PM, Cyrill Gorcunov wrote:
> > On Tue, Aug 21, 2012 at 02:49:47PM +0400, Pavel Emelyanov wrote:
> >>>>
> >>>> However, if you have some better ideas on what information about inode should be exported
> >>>> to the userspace please share.
> >>>>
> >>>
> >>> Why not use name_to_handle(fd,...) and open_by_handle(handle,..) ?
> >>
> >> Because we don't have an fd at hands by the time we need to know the handle.
> > 
> > Yeah, this might be not clear from patchset itself but inotify marks carry
> > inodes inside kernel thus it's inodes what we can use when we fetch information
> > about targets and put it into fdinfo output.
> 
> Al, Bruce, Aneesh,
> 
> What if we calculate the handle at the time we do have struct path at hands (i.e.
> when we create the inotify) and store it on the inotify structure purely to be 
> shown later in proc. Would that be acceptable?

Was it the lack of a dentry that was really the problem?  I thought it
was just the fact that not all filesystems support filehandles.

--b.