Subject: nfs commit breaks build for nfs4.1=y nfs4.2=n

From: Paul Gortmaker <[email-masked]>
Date: Thu, 25 Jun 2015 10:55:28 -0400

New breakage seen in linux-next:

fs/nfs/pnfs.c:2293: undefined reference to
`nfs42_proc_layoutstats_generic'

...bisected to:

commit 8733408d6ed713d080c325262d7b51a780136d41
Author: Peng Tao <[email-masked]>
Date:   Tue Jun 23 19:51:57 2015 +0800

    pnfs: add pnfs_report_layoutstat helper function

Probably caused by the unusual defconfig having:

$ grep NFS .config
CONFIG_KERNFS=y
CONFIG_NFS_FS=y
CONFIG_NFS_V2=y
CONFIG_NFS_V3=y
# CONFIG_NFS_V3_ACL is not set
CONFIG_NFS_V4=y
# CONFIG_NFS_SWAP is not set
CONFIG_NFS_V4_1=y			<------------
# CONFIG_NFS_V4_2 is not set		<------------
CONFIG_PNFS_FILE_LAYOUT=y
CONFIG_PNFS_FLEXFILE_LAYOUT=m
CONFIG_NFS_V4_1_IMPLEMENTATION_ID_DOMAIN="kernel.org"
# CONFIG_NFS_V4_1_MIGRATION is not set
CONFIG_ROOT_NFS=y
# CONFIG_NFS_USE_LEGACY_DNS is not set
CONFIG_NFS_USE_KERNEL_DNS=y
# CONFIG_NFSD is not set
CONFIG_NFS_COMMON=y

http://kisskb.ellerman.id.au/kisskb/buildresult/12449989/