Re: [PATCH 3/5] exportfs: make ->encode_fh() a mandatory method for NFS export

From: Chuck Lever <chuck.lever@oracle.com>
To: Amir Goldstein <amir73il@gmail.com>
Cc: Jan Kara <jack@suse.cz>, Jeff Layton <jlayton@kernel.org>,
	Christian Brauner <brauner@kernel.org>,
	linux-fsdevel@vger.kernel.org, linux-nfs@vger.kernel.org,
	David Sterba <dsterba@suse.com>,
	Luis de Bethencourt <luisbg@kernel.org>,
	Salah Triki <salah.triki@gmail.com>, Gao Xiang <xiang@kernel.org>,
	Chao Yu <chao@kernel.org>, Theodore Ts'o <tytso@mit.edu>,
	Andreas Dilger <adilger.kernel@dilger.ca>,
	Jaegeuk Kim <jaegeuk@kernel.org>,
	OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>,
	Dave Kleikamp <shaggy@kernel.org>,
	David Woodhouse <dwmw2@infradead.org>,
	Richard Weinberger <richard@nod.at>,
	Anton Altaparmakov <anton@tuxera.com>,
	Konstantin Komarov <almaz.alexandrovich@paragon-software.com>,
	Steve French <sfrench@samba.org>,
	Phillip Lougher <phillip@squashfs.org.uk>,
	Evgeniy Dushistov <dushistov@mail.ru>
Subject: Re: [PATCH 3/5] exportfs: make ->encode_fh() a mandatory method for NFS export
Date: Wed, 18 Oct 2023 11:36:29 -0400	[thread overview]
Message-ID: <ZS/7fQWxuwaUIt/O@tissot.1015granger.net> (raw)
In-Reply-To: <CAOQ4uxj4CQmVKvmLg0UdNJWZ14Dp6SjJUvwqFdO3u9--M4dH6g@mail.gmail.com>

On Wed, Oct 18, 2023 at 06:26:07PM +0300, Amir Goldstein wrote:
> On Wed, Oct 18, 2023 at 6:18 PM Chuck Lever <chuck.lever@oracle.com> wrote:
> >
> > On Wed, Oct 18, 2023 at 12:59:58PM +0300, Amir Goldstein wrote:
> > > export_operations ->encode_fh() no longer has a default implementation to
> > > encode FILEID_INO32_GEN* file handles.
> > >
> > > Rename the default helper for encoding FILEID_INO32_GEN* file handles to
> > > generic_encode_ino32_fh() and convert the filesystems that used the
> > > default implementation to use the generic helper explicitly.
> > >
> > > This is a step towards allowing filesystems to encode non-decodeable file
> > > handles for fanotify without having to implement any export_operations.
> > >
> > > Signed-off-by: Amir Goldstein <amir73il@gmail.com>
> > > ---
> [...]
> 
> > > diff --git a/include/linux/exportfs.h b/include/linux/exportfs.h
> > > index 5b3c9f30b422..6b6e01321405 100644
> > > --- a/include/linux/exportfs.h
> > > +++ b/include/linux/exportfs.h
> > > @@ -235,7 +235,7 @@ extern int exportfs_encode_fh(struct dentry *dentry, struct fid *fid,
> > >
> > >  static inline bool exportfs_can_encode_fid(const struct export_operations *nop)
> > >  {
> > > -     return nop;
> > > +     return nop && nop->encode_fh;
> >
> > The ->encode_fh() method returns an integer type, not a boolean. It
> > would be more clear if this were written
> >
> >         return nop && (nop->encode_fh != FILEID_ROOT);
> >
> > (I'm just guessing at what you might have intended).
> >
> 
> You must be pre-coffee ;)

More like pre-lunch.

> This checks if the method exists, it doesn't invoke the method.

OK, I was confused because I thought you were filling in all the
spots where the method doesn't already exist. My brain lept to
the conclusion that this is therefore calling the method, but I
failed to notice there are no call arguments.

I might understand it now. :-)

Since you want this series to go through the vfs tree:

Acked-by: Chuck Lever <chuck.lever@oracle.com>

-- 
Chuck Lever