[LTP] [PATCH 2/2] nfsstat01: Check that RPC stats don't leak between net namespaces

[Martin Doucha]

When the NFS server and client run on the same host in different net
namespaces, check that RPC calls from the client namespace don't
change RPC statistics in the root namespace.

Signed-off-by: Martin Doucha <mdoucha@suse.cz>
---

I've initially tried to test both NFS and RPC client stats but it appears
that NFS client stats are still shared across all namespaces. Only RPC
client stats are separate for each net namespace. The kernel patchset[1]
which introduced per-NS stats confirms that only RPC stats have been changed.

If NFS client stats should be separate for each namespace as well, let
me know and I'll return the second set of NS checks in patch v2.

Tested on kernel v5.14 with Neil's backports.

[1] https://lore.kernel.org/linux-nfs/cover.1708026931.git.josef@toxicpanda.com/

 testcases/network/nfs/nfsstat01/nfsstat01.sh | 18 ++++++++++++++++--
 1 file changed, 16 insertions(+), 2 deletions(-)

diff --git a/testcases/network/nfs/nfsstat01/nfsstat01.sh b/testcases/network/nfs/nfsstat01/nfsstat01.sh
index 8d7202cf3..3379c4d46 100755
--- a/testcases/network/nfs/nfsstat01/nfsstat01.sh
+++ b/testcases/network/nfs/nfsstat01/nfsstat01.sh
@@ -22,6 +22,7 @@ get_calls()
 	local name=$1
 	local field=$2
 	local nfs_f=$3
+	local netns=${4:-rhost}
 	local type="lhost"
 	local calls opt
 
@@ -30,7 +31,8 @@ get_calls()
 
 	if tst_net_use_netns; then
 		# In netns setup, rhost is the client
-		[ "$nfs_f" = "nfs" ] && [ $NS_STAT_RHOST -ne 0 ] && type="rhost"
+		[ "$nfs_f" = "nfs" ] && [ $NS_STAT_RHOST -ne 0 ] && \
+			type="$netns"
 	else
 		[ "$nfs_f" != "nfs" ] && type="rhost"
 	fi
@@ -64,13 +66,14 @@ get_calls()
 do_test()
 {
 	local client_calls server_calls new_server_calls new_client_calls
-	local client_field server_field
+	local client_field server_field root_calls new_root_calls
 	local client_v=$VERSION server_v=$VERSION
 
 	tst_res TINFO "checking RPC calls for server/client"
 
 	server_calls="$(get_calls rpc 2 nfsd)"
 	client_calls="$(get_calls rpc 2 nfs)"
+	root_calls="$(get_calls rpc 2 nfs lhost)"
 
 	tst_res TINFO "calls $server_calls/$client_calls"
 
@@ -79,6 +82,7 @@ do_test()
 
 	new_server_calls="$(get_calls rpc 2 nfsd)"
 	new_client_calls="$(get_calls rpc 2 nfs)"
+	new_root_calls="$(get_calls rpc 2 nfs lhost)"
 	tst_res TINFO "new calls $new_server_calls/$new_client_calls"
 
 	if [ "$new_server_calls" -le "$server_calls" ]; then
@@ -93,6 +97,16 @@ do_test()
 		tst_res TPASS "client RPC calls increased"
 	fi
 
+	if [ $NS_STAT_RHOST -ne 0 ]; then
+		tst_res TINFO "Root NS client RPC calls: $root_calls => $new_root_calls"
+
+		if [ $root_calls -ne $new_root_calls ]; then
+			tst_res TFAIL "RPC stats leaked between net namespaces"
+		else
+			tst_res TPASS "RPC stats stay within net namespaces"
+		fi
+	fi
+
 	tst_res TINFO "checking NFS calls for server/client"
 	case $VERSION in
 	2) client_field=13 server_field=13
-- 
2.46.0