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From:   "NeilBrown" <neilb@suse.de>
To:     "Al Viro" <viro@zeniv.linux.org.uk>
Cc:     "Christoph Hellwig" <hch@infradead.org>,
        "Josef Bacik" <josef@toxicpanda.com>,
        "J. Bruce Fields" <bfields@fieldses.org>,
        "Chuck Lever" <chuck.lever@oracle.com>, "Chris Mason" <clm@fb.com>,
        "David Sterba" <dsterba@suse.com>, linux-fsdevel@vger.kernel.org,
        linux-nfs@vger.kernel.org, linux-btrfs@vger.kernel.org
Subject: Re: [PATCH 04/11] VFS: export lookup_mnt()
In-reply-to: <YQNIUA6NKmSgdawv@zeniv-ca.linux.org.uk>
References: <162742539595.32498.13687924366155737575.stgit@noble.brown>,
 <162742546551.32498.5847026750506620683.stgit@noble.brown>,
 <YQNIUA6NKmSgdawv@zeniv-ca.linux.org.uk>
Date:   Fri, 30 Jul 2021 15:33:26 +1000
Message-id: <162762320688.21659.7949785958006573635@noble.neil.brown.name>
Precedence: bulk

On Fri, 30 Jul 2021, Al Viro wrote:
> On Wed, Jul 28, 2021 at 08:37:45AM +1000, NeilBrown wrote:
> > In order to support filehandle lookup in filesystems with internal
> > mounts (multiple subvols in the one filesystem) reconnect_path() in
> > exportfs will need to find out if a given dentry is already mounted.
> > This can be done with the function lookup_mnt(), so export that to make
> > it available.
> 
> IMO having exportfs modular is wrong - note that fs/fhandle.c is
> 	* calling functions in exportfs
> 	* non-modular
> 	* ... and not going to be modular, no matter what - there
> are syscalls in it.
> 
> 

I agree - it makes sense for exportfs to be non-module.  It cannot be
module if FHANDLE is enabled, and if you don't want FHANDLE you probably
don't want EXPORTFS either.

Thanks,
NeilBrown