[nfs-utils PATCH 0/3] mountd netlink fixes

[nfs-utils PATCH 0/3] mountd netlink fixes

[Scott Mayhew]

A handful of fixes for some issues I ran into on Fedora Rawhide.

Scott Mayhew (3):
  configure: update check of system netlink headers
  nfs.conf: add no-netlink option to exportd and mountd stanzas
  mountd/exportd: disable netlink when falling back to /proc

 configure.ac                 | 4 ++--
 nfs.conf                     | 3 +++
 support/export/cache.c       | 7 +++++++
 support/export/cache_flush.c | 1 +
 4 files changed, 13 insertions(+), 2 deletions(-)

-- 
2.55.0

[nfs-utils PATCH 1/3] configure: update check of system netlink headers

[Scott Mayhew]

Commit e1401387 ("nfsstat: add netlink support for fetching server
statistics") added new symbols to support/include/nfsd_netlink.h
that have not yet been added to the kernel headers.  Update the check
that defines USE_SYSTEM_NFSD_NETLINK_H - otherwise nfsstat will fail
to compile.

Signed-off-by: Scott Mayhew <smayhew@redhat.com>
---
 configure.ac | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/configure.ac b/configure.ac
index 8ca06fd6..4ca7666d 100644
--- a/configure.ac
+++ b/configure.ac
@@ -259,9 +259,9 @@ AC_CHECK_HEADERS(linux/nfsd_netlink.h)
 AC_DEFINE([HAVE_NFSD_NETLINK], 1,
 	  [Define to 1 if nfsd generic netlink support is available])
 
-# ensure we have the expkey attributes
+# ensure the system netlink headers have the latest features
 AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[#include <linux/nfsd_netlink.h>]],
-			                   [[int foo = NFSD_A_EXPKEY_SEQNO;]])],
+			                   [[int foo = NFSD_CMD_SERVER_STATS_GET;]])],
 			   [AC_DEFINE([USE_SYSTEM_NFSD_NETLINK_H], 1,
 				      ["Use system's linux/nfsd_netlink.h"])])
 AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[#include <linux/lockd_netlink.h>]],
-- 
2.55.0

[nfs-utils PATCH 2/3] nfs.conf: add no-netlink option to exportd and mountd stanzas

[Scott Mayhew]

This option was added by commit 60c38383 ("mountd/exportd/exportfs:
add --no-netlink option to disable netlink"), but nfs.conf was not
updated.

Signed-off-by: Scott Mayhew <smayhew@redhat.com>
---
 nfs.conf | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/nfs.conf b/nfs.conf
index 84cc653f..fa12c592 100644
--- a/nfs.conf
+++ b/nfs.conf
@@ -43,6 +43,8 @@
 # threads=1
 # cache-use-ipaddr=n
 # ttl=1800
+# no-netlink=0
+#
 [mountd]
 # debug="all|auth|call|general|parse"
 # apply-root-cred=n
@@ -55,6 +57,7 @@
 # ha-callout=
 # cache-use-ipaddr=n
 # ttl=1800
+# no-netlink=0
 #
 [nfsdcld]
 # debug=0
-- 
2.55.0

[nfs-utils PATCH 3/3] mountd/exportd: disable netlink when falling back to /proc

[Scott Mayhew]

If cache_flush() has to fall back to the /proc interface, then there's a
good chance that the netlink interface isn't going to work, so go ahead
and disable it.

The netlink interface requires CAP_NET_ADMIN, which requires a policy
update on systems running SELinux.  If SELinux blocks mountd from using
the netlink interface and there's no fallback, then mount requests just
hang.

Also, when falling back, close both the sunrpc and the nfsd netlink
sockets.

Signed-off-by: Scott Mayhew <smayhew@redhat.com>
---
 support/export/cache.c       | 7 +++++++
 support/export/cache_flush.c | 1 +
 2 files changed, 8 insertions(+)

diff --git a/support/export/cache.c b/support/export/cache.c
index 65008f51..059f48a7 100644
--- a/support/export/cache.c
+++ b/support/export/cache.c
@@ -3072,6 +3072,8 @@ void cache_open(void)
 			 * were queued before we opened the socket.
 			 */
 			auth_reload();
+			if (no_netlink)
+				goto fallback;
 			cache_nl_process_export();
 			cache_nl_process_expkey();
 			cache_nl_process_ip_map();
@@ -3079,11 +3081,16 @@ void cache_open(void)
 				cache_nl_process_unix_gid();
 			return;
 		}
+fallback:
 		xlog(L_NOTICE, "sunrpc netlink family unavailable, falling back to /proc");
 		nl_socket_free(nfsd_nl_notify_sock);
 		nfsd_nl_notify_sock = NULL;
 		nl_socket_free(nfsd_nl_cmd_sock);
 		nfsd_nl_cmd_sock = NULL;
+		nl_socket_free(sunrpc_nl_notify_sock);
+		sunrpc_nl_notify_sock = NULL;
+		nl_socket_free(sunrpc_nl_cmd_sock);
+		sunrpc_nl_cmd_sock = NULL;
 	}
 
 	for (i=0; cachelist[i].cache_name; i++ ) {
diff --git a/support/export/cache_flush.c b/support/export/cache_flush.c
index 2a24dec7..046e6917 100644
--- a/support/export/cache_flush.c
+++ b/support/export/cache_flush.c
@@ -164,5 +164,6 @@ cache_flush(void)
 		return;
 	}
 	/* Fallback: /proc path */
+	no_netlink = 1;
 	cache_proc_flush();
 }
-- 
2.55.0

Re: [nfs-utils PATCH 0/3] mountd netlink fixes

[Jeff Layton]

On Tue, 2026-07-07 at 16:57 -0400, Scott Mayhew wrote:
> A handful of fixes for some issues I ran into on Fedora Rawhide.
> 
> Scott Mayhew (3):
>   configure: update check of system netlink headers
>   nfs.conf: add no-netlink option to exportd and mountd stanzas
>   mountd/exportd: disable netlink when falling back to /proc
> 
>  configure.ac                 | 4 ++--
>  nfs.conf                     | 3 +++
>  support/export/cache.c       | 7 +++++++
>  support/export/cache_flush.c | 1 +
>  4 files changed, 13 insertions(+), 2 deletions(-)

These all look good to me. Nice work, Scott.

Reviewed-by: Jeff Layton <jlayton@kernel.org>

Re: [nfs-utils PATCH 0/3] mountd netlink fixes

[Steve Dickson]

On 7/7/26 4:57 PM, Scott Mayhew wrote:
> A handful of fixes for some issues I ran into on Fedora Rawhide.
> 
> Scott Mayhew (3):
>    configure: update check of system netlink headers
>    nfs.conf: add no-netlink option to exportd and mountd stanzas
>    mountd/exportd: disable netlink when falling back to /proc
> 
>   configure.ac                 | 4 ++--
>   nfs.conf                     | 3 +++
>   support/export/cache.c       | 7 +++++++
>   support/export/cache_flush.c | 1 +
>   4 files changed, 13 insertions(+), 2 deletions(-)
> 
Committed... (tag: nfs-utils-2-9-2-rc5)

steved.