[PATCH 2/2] NFSv4: Use the net namespace uniquifier if it is set

[trondmy@kernel.org]

From: Trond Myklebust <trond.myklebust@hammerspace.com>

If a container sets a net namespace specific uniquifier, then use that
in the setclientid/exchangeid process.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
---
 fs/nfs/nfs4proc.c | 23 ++++++++++++++++++++---
 1 file changed, 20 insertions(+), 3 deletions(-)

diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
index 3a39887e0e6e..a1dd46e7440b 100644
--- a/fs/nfs/nfs4proc.c
+++ b/fs/nfs/nfs4proc.c
@@ -63,6 +63,7 @@
 #include "callback.h"
 #include "pnfs.h"
 #include "netns.h"
+#include "sysfs.h"
 #include "nfs4idmap.h"
 #include "nfs4session.h"
 #include "fscache.h"
@@ -6007,9 +6008,25 @@ static void nfs4_init_boot_verifier(const struct nfs_client *clp,
 }
 
 static size_t
-nfs4_get_uniquifier(char *buf, size_t buflen)
+nfs4_get_uniquifier(struct nfs_client *clp, char *buf, size_t buflen)
 {
+	struct nfs_net *nn = net_generic(clp->cl_net, nfs_net_id);
+	struct nfs_netns_client *nn_clp = nn->nfs_client;
+	const char *id;
+	size_t len;
+
 	buf[0] = '\0';
+
+	if (nn_clp) {
+		rcu_read_lock();
+		id = rcu_dereference(nn_clp->identifier);
+		if (id && *id != '\0')
+			len = strlcpy(buf, id, buflen);
+		rcu_read_unlock();
+		if (len)
+			return len;
+	}
+
 	if (nfs4_client_id_uniquifier[0] != '\0')
 		return strlcpy(buf, nfs4_client_id_uniquifier, buflen);
 	return 0;
@@ -6034,7 +6051,7 @@ nfs4_init_nonuniform_client_string(struct nfs_client *clp)
 		1;
 	rcu_read_unlock();
 
-	buflen = nfs4_get_uniquifier(buf, sizeof(buf));
+	buflen = nfs4_get_uniquifier(clp, buf, sizeof(buf));
 	if (buflen)
 		len += buflen + 1;
 
@@ -6081,7 +6098,7 @@ nfs4_init_uniform_client_string(struct nfs_client *clp)
 	len = 10 + 10 + 1 + 10 + 1 +
 		strlen(clp->cl_rpcclient->cl_nodename) + 1;
 
-	buflen = nfs4_get_uniquifier(buf, sizeof(buf));
+	buflen = nfs4_get_uniquifier(clp, buf, sizeof(buf));
 	if (buflen)
 		len += buflen + 1;
 
-- 
2.26.2