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From:   Jeff Layton <jlayton@kernel.org>
To:     chuck.lever@oracle.com
Cc:     linux-nfs@vger.kernel.org
Subject: [PATCH] nfsd: allow disabling NFSv2 at compile time
Date:   Mon, 17 Oct 2022 12:53:53 -0400
Message-Id: <20221017165353.462811-1-jlayton@kernel.org>
MIME-Version: 1.0
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rpc.nfsd stopped supporting NFSv2 a year ago, take the next logical
step toward deprecating it and allow NFSv2 to be compiled out.

We have long-term goal to deprecate NFSv2 in modern kernels. As a step
toward that, allow disabling NFSv2 serving altogether at compile time.
Add a new CONFIG_NFSD_V2 option, that can be turned off and rework the
CONFIG_NFSD_V?_ACL option dependencies.

Fix the "versions" file to properly reject versions that aren't compiled
in, and change the description of CONFIG_NFSD to state that the always-on
version is 3 now instead of 2.

Suggested-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Jeff Layton <jlayton@kernel.org>
---
 fs/nfsd/Kconfig   | 12 ++++++---
 fs/nfsd/Makefile  |  5 ++--
 fs/nfsd/export.c  | 61 ++++++++++++++++++++++++++++++++++++++++++++++
 fs/nfsd/nfsctl.c  |  4 +++
 fs/nfsd/nfsd.h    |  3 +--
 fs/nfsd/nfsproc.c | 62 -----------------------------------------------
 fs/nfsd/nfssvc.c  |  6 +++++
 7 files changed, 83 insertions(+), 70 deletions(-)

diff --git a/fs/nfsd/Kconfig b/fs/nfsd/Kconfig
index f6a2fd3015e7..c3c43b5e3892 100644
--- a/fs/nfsd/Kconfig
+++ b/fs/nfsd/Kconfig
@@ -8,6 +8,7 @@ config NFSD
 	select SUNRPC
 	select EXPORTFS
 	select NFS_ACL_SUPPORT if NFSD_V2_ACL
+	select NFS_ACL_SUPPORT if NFSD_V3_ACL
 	depends on MULTIUSER
 	help
 	  Choose Y here if you want to allow other computers to access
@@ -26,19 +27,22 @@ config NFSD
 
 	  Below you can choose which versions of the NFS protocol are
 	  available to clients mounting the NFS server on this system.
-	  Support for NFS version 2 (RFC 1094) is always available when
+	  Support for NFS version 3 (RFC 1813) is always available when
 	  CONFIG_NFSD is selected.
 
 	  If unsure, say N.
 
-config NFSD_V2_ACL
-	bool
+config NFSD_V2
+	bool "NFS server support for NFS version 2"
 	depends on NFSD
 
+config NFSD_V2_ACL
+	bool "NFS server support for the NFSv2 ACL protocol extension"
+	depends on NFSD_V2
+
 config NFSD_V3_ACL
 	bool "NFS server support for the NFSv3 ACL protocol extension"
 	depends on NFSD
-	select NFSD_V2_ACL
 	help
 	  Solaris NFS servers support an auxiliary NFSv3 ACL protocol that
 	  never became an official part of the NFS version 3 protocol.
diff --git a/fs/nfsd/Makefile b/fs/nfsd/Makefile
index 805c06d5f1b4..6fffc8f03f74 100644
--- a/fs/nfsd/Makefile
+++ b/fs/nfsd/Makefile
@@ -10,9 +10,10 @@ obj-$(CONFIG_NFSD)	+= nfsd.o
 # this one should be compiled first, as the tracing macros can easily blow up
 nfsd-y			+= trace.o
 
-nfsd-y 			+= nfssvc.o nfsctl.o nfsproc.o nfsfh.o vfs.o \
-			   export.o auth.o lockd.o nfscache.o nfsxdr.o \
+nfsd-y 			+= nfssvc.o nfsctl.o nfsfh.o vfs.o \
+			   export.o auth.o lockd.o nfscache.o \
 			   stats.o filecache.o nfs3proc.o nfs3xdr.o
+nfsd-$(CONFIG_NFSD_V2) += nfsproc.o nfsxdr.o
 nfsd-$(CONFIG_NFSD_V2_ACL) += nfs2acl.o
 nfsd-$(CONFIG_NFSD_V3_ACL) += nfs3acl.o
 nfsd-$(CONFIG_NFSD_V4)	+= nfs4proc.o nfs4xdr.o nfs4state.o nfs4idmap.o \
diff --git a/fs/nfsd/export.c b/fs/nfsd/export.c
index 668c7527b17e..20ba051f89a2 100644
--- a/fs/nfsd/export.c
+++ b/fs/nfsd/export.c
@@ -1183,6 +1183,67 @@ exp_pseudoroot(struct svc_rqst *rqstp, struct svc_fh *fhp)
 	return rv;
 }
 
+/*
+ * Map errnos to NFS errnos.
+ */
+__be32
+nfserrno (int errno)
+{
+	static struct {
+		__be32	nfserr;
+		int	syserr;
+	} nfs_errtbl[] = {
+		{ nfs_ok, 0 },
+		{ nfserr_perm, -EPERM },
+		{ nfserr_noent, -ENOENT },
+		{ nfserr_io, -EIO },
+		{ nfserr_nxio, -ENXIO },
+		{ nfserr_fbig, -E2BIG },
+		{ nfserr_stale, -EBADF },
+		{ nfserr_acces, -EACCES },
+		{ nfserr_exist, -EEXIST },
+		{ nfserr_xdev, -EXDEV },
+		{ nfserr_mlink, -EMLINK },
+		{ nfserr_nodev, -ENODEV },
+		{ nfserr_notdir, -ENOTDIR },
+		{ nfserr_isdir, -EISDIR },
+		{ nfserr_inval, -EINVAL },
+		{ nfserr_fbig, -EFBIG },
+		{ nfserr_nospc, -ENOSPC },
+		{ nfserr_rofs, -EROFS },
+		{ nfserr_mlink, -EMLINK },
+		{ nfserr_nametoolong, -ENAMETOOLONG },
+		{ nfserr_notempty, -ENOTEMPTY },
+#ifdef EDQUOT
+		{ nfserr_dquot, -EDQUOT },
+#endif
+		{ nfserr_stale, -ESTALE },
+		{ nfserr_jukebox, -ETIMEDOUT },
+		{ nfserr_jukebox, -ERESTARTSYS },
+		{ nfserr_jukebox, -EAGAIN },
+		{ nfserr_jukebox, -EWOULDBLOCK },
+		{ nfserr_jukebox, -ENOMEM },
+		{ nfserr_io, -ETXTBSY },
+		{ nfserr_notsupp, -EOPNOTSUPP },
+		{ nfserr_toosmall, -ETOOSMALL },
+		{ nfserr_serverfault, -ESERVERFAULT },
+		{ nfserr_serverfault, -ENFILE },
+		{ nfserr_io, -EREMOTEIO },
+		{ nfserr_stale, -EOPENSTALE },
+		{ nfserr_io, -EUCLEAN },
+		{ nfserr_perm, -ENOKEY },
+		{ nfserr_no_grace, -ENOGRACE},
+	};
+	int	i;
+
+	for (i = 0; i < ARRAY_SIZE(nfs_errtbl); i++) {
+		if (nfs_errtbl[i].syserr == errno)
+			return nfs_errtbl[i].nfserr;
+	}
+	WARN_ONCE(1, "nfsd: non-standard errno: %d\n", errno);
+	return nfserr_io;
+}
+
 static struct flags {
 	int flag;
 	char *name[2];
diff --git a/fs/nfsd/nfsctl.c b/fs/nfsd/nfsctl.c
index dc74a947a440..02ed0babd98c 100644
--- a/fs/nfsd/nfsctl.c
+++ b/fs/nfsd/nfsctl.c
@@ -581,10 +581,13 @@ static ssize_t __write_versions(struct file *file, char *buf, size_t size)
 
 			cmd = sign == '-' ? NFSD_CLEAR : NFSD_SET;
 			switch(num) {
+#ifdef CONFIG_NFSD_V2
 			case 2:
+#endif
 			case 3:
 				nfsd_vers(nn, num, cmd);
 				break;
+#ifdef CONFIG_NFSD_V4
 			case 4:
 				if (*minorp == '.') {
 					if (nfsd_minorversion(nn, minor, cmd) < 0)
@@ -600,6 +603,7 @@ static ssize_t __write_versions(struct file *file, char *buf, size_t size)
 						minor++;
 				}
 				break;
+#endif
 			default:
 				return -EINVAL;
 			}
diff --git a/fs/nfsd/nfsd.h b/fs/nfsd/nfsd.h
index 09726c5b9a31..93b42ef9ed91 100644
--- a/fs/nfsd/nfsd.h
+++ b/fs/nfsd/nfsd.h
@@ -64,8 +64,7 @@ struct readdir_cd {
 
 
 extern struct svc_program	nfsd_program;
-extern const struct svc_version	nfsd_version2, nfsd_version3,
-				nfsd_version4;
+extern const struct svc_version	nfsd_version2, nfsd_version3, nfsd_version4;
 extern struct mutex		nfsd_mutex;
 extern spinlock_t		nfsd_drc_lock;
 extern unsigned long		nfsd_drc_max_mem;
diff --git a/fs/nfsd/nfsproc.c b/fs/nfsd/nfsproc.c
index 82b3ddeacc33..52fc222c34f2 100644
--- a/fs/nfsd/nfsproc.c
+++ b/fs/nfsd/nfsproc.c
@@ -848,65 +848,3 @@ const struct svc_version nfsd_version2 = {
 	.vs_dispatch	= nfsd_dispatch,
 	.vs_xdrsize	= NFS2_SVC_XDRSIZE,
 };
-
-/*
- * Map errnos to NFS errnos.
- */
-__be32
-nfserrno (int errno)
-{
-	static struct {
-		__be32	nfserr;
-		int	syserr;
-	} nfs_errtbl[] = {
-		{ nfs_ok, 0 },
-		{ nfserr_perm, -EPERM },
-		{ nfserr_noent, -ENOENT },
-		{ nfserr_io, -EIO },
-		{ nfserr_nxio, -ENXIO },
-		{ nfserr_fbig, -E2BIG },
-		{ nfserr_stale, -EBADF },
-		{ nfserr_acces, -EACCES },
-		{ nfserr_exist, -EEXIST },
-		{ nfserr_xdev, -EXDEV },
-		{ nfserr_mlink, -EMLINK },
-		{ nfserr_nodev, -ENODEV },
-		{ nfserr_notdir, -ENOTDIR },
-		{ nfserr_isdir, -EISDIR },
-		{ nfserr_inval, -EINVAL },
-		{ nfserr_fbig, -EFBIG },
-		{ nfserr_nospc, -ENOSPC },
-		{ nfserr_rofs, -EROFS },
-		{ nfserr_mlink, -EMLINK },
-		{ nfserr_nametoolong, -ENAMETOOLONG },
-		{ nfserr_notempty, -ENOTEMPTY },
-#ifdef EDQUOT
-		{ nfserr_dquot, -EDQUOT },
-#endif
-		{ nfserr_stale, -ESTALE },
-		{ nfserr_jukebox, -ETIMEDOUT },
-		{ nfserr_jukebox, -ERESTARTSYS },
-		{ nfserr_jukebox, -EAGAIN },
-		{ nfserr_jukebox, -EWOULDBLOCK },
-		{ nfserr_jukebox, -ENOMEM },
-		{ nfserr_io, -ETXTBSY },
-		{ nfserr_notsupp, -EOPNOTSUPP },
-		{ nfserr_toosmall, -ETOOSMALL },
-		{ nfserr_serverfault, -ESERVERFAULT },
-		{ nfserr_serverfault, -ENFILE },
-		{ nfserr_io, -EREMOTEIO },
-		{ nfserr_stale, -EOPENSTALE },
-		{ nfserr_io, -EUCLEAN },
-		{ nfserr_perm, -ENOKEY },
-		{ nfserr_no_grace, -ENOGRACE},
-	};
-	int	i;
-
-	for (i = 0; i < ARRAY_SIZE(nfs_errtbl); i++) {
-		if (nfs_errtbl[i].syserr == errno)
-			return nfs_errtbl[i].nfserr;
-	}
-	WARN_ONCE(1, "nfsd: non-standard errno: %d\n", errno);
-	return nfserr_io;
-}
-
diff --git a/fs/nfsd/nfssvc.c b/fs/nfsd/nfssvc.c
index bfbd9f672f59..62e473b0ca52 100644
--- a/fs/nfsd/nfssvc.c
+++ b/fs/nfsd/nfssvc.c
@@ -91,8 +91,12 @@ unsigned long	nfsd_drc_mem_used;
 #if defined(CONFIG_NFSD_V2_ACL) || defined(CONFIG_NFSD_V3_ACL)
 static struct svc_stat	nfsd_acl_svcstats;
 static const struct svc_version *nfsd_acl_version[] = {
+# if defined(CONFIG_NFSD_V2_ACL)
 	[2] = &nfsd_acl_version2,
+# endif
+# if defined(CONFIG_NFSD_V3_ACL)
 	[3] = &nfsd_acl_version3,
+# endif
 };
 
 #define NFSD_ACL_MINVERS            2
@@ -116,7 +120,9 @@ static struct svc_stat	nfsd_acl_svcstats = {
 #endif /* defined(CONFIG_NFSD_V2_ACL) || defined(CONFIG_NFSD_V3_ACL) */
 
 static const struct svc_version *nfsd_version[] = {
+#if defined(CONFIG_NFSD_V2)
 	[2] = &nfsd_version2,
+#endif
 	[3] = &nfsd_version3,
 #if defined(CONFIG_NFSD_V4)
 	[4] = &nfsd_version4,
-- 
2.37.3