Re: [PATCH] nfsd: Fix build error

[Bruce Fields]

On Wed, Mar 04, 2020 at 01:00:12PM -0500, Chuck Lever wrote:
> Hi-
> 
> > On Mar 4, 2020, at 8:18 AM, YueHaibing <yuehaibing@xxxxxxxxxx> wrote:
> > 
> > fs/nfsd/nfs4proc.o: In function `nfsd4_do_copy':
> > nfs4proc.c:(.text+0x23b7): undefined reference to `nfs42_ssc_close'
> > fs/nfsd/nfs4proc.o: In function `nfsd4_copy':
> > nfs4proc.c:(.text+0x5d2a): undefined reference to `nfs_sb_deactive'
> > fs/nfsd/nfs4proc.o: In function `nfsd4_do_async_copy':
> > nfs4proc.c:(.text+0x61d5): undefined reference to `nfs42_ssc_open'
> > nfs4proc.c:(.text+0x6389): undefined reference to `nfs_sb_deactive'
> > 
> > Add dependency to NFSD_V4_2_INTER_SSC to fix this.
> > 
> > Fixes: ce0887ac96d3 ("NFSD add nfs4 inter ssc to nfsd4_copy")
> > Signed-off-by: YueHaibing <yuehaibing@xxxxxxxxxx>
> > ---
> > fs/nfsd/Kconfig | 1 +
> > 1 file changed, 1 insertion(+)
> > 
> > diff --git a/fs/nfsd/Kconfig b/fs/nfsd/Kconfig
> > index f368f32..fc587a5 100644
> > --- a/fs/nfsd/Kconfig
> > +++ b/fs/nfsd/Kconfig
> > @@ -136,6 +136,7 @@ config NFSD_FLEXFILELAYOUT
> > 
> > config NFSD_V4_2_INTER_SSC
> > 	bool "NFSv4.2 inter server to server COPY"
> > +	depends on !(NFSD=y && NFS_FS=m)
> 
> The new dependency is not especially clear to me; more explanation
> in the patch description about the cause of the build failure
> would definitely be helpful.
> 
> NFSD_V4 can't be set unless NFSD is also set.
> 
> NFS_V4_2 can't be set unless NFS_V4_1 is also set, and that cannot
> be set unless NFS_FS is also set.
> 
> So what's really going on here?

I don't understand that "depends" either.

The fundamental problem, though, is that nfsd is calling nfs code
directly.

Which I noticed in earlier review and then forgot to follow up on,
sorry.

So either we:

	- let nfsd depend on nfs, fix up Kconfig to reflect the fact, or
	- write some code so nfsd can load nfs and find those symbols at
	  runtime if it needs to do a copy.

The latter's certainly doable, but it'd be simplest to do the former.
Are there actually a lot of people who want nfsd but not nfs?  Does that
cause a real problem for anyone?

--b.