Re: [PATCH] nfsd: Fix build error

["Kornievskaia, Olga" <Olga.Kornievskaia@netapp.com>]

On 3/4/20, 4:05 PM, "Chuck Lever" <chuck.lever@oracle.com> wrote:

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    > On Mar 4, 2020, at 3:06 PM, Bruce Fields <bfields@fieldses.org> wrote:
    >
    > On Wed, Mar 04, 2020 at 01:00:12PM -0500, Chuck Lever wrote:
    >> Hi-
    >>
    >>> On Mar 4, 2020, at 8:18 AM, YueHaibing <yuehaibing@huawei.com> 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@huawei.com>
    >>> ---
    >>> 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.
    
    Another practical option would be to create a copy of these functions in
    the server's SSC code. At least nfs_sb_deactive() is not large.
    
    Not clear if nfs42_ssc_open/close are even used on the client. Maybe they
    could be moved to the server?

Nfs42_ssc_open/close are not used on the client but their insides use client's structures (like nfs_fh, nfs4_stateid, etc) and calls nfs4_proc_getattr, nfs_fhget and others and VFS functions. It'll be a lot to 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.
    
    --
    Chuck Lever