Re: [PATCH] nfsd: Fix build error

[Yuehaibing <yuehaibing@huawei.com>]

On 2020/3/5 4:06, Bruce Fields 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.

Yes

> 
> 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

It only fails while NFSD=y && NFS_FS=m, other cases works fine as Chuck Lever pointed.

> 	- 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.
> 
> .
>