[Devel] [PATCH vz9 7/9] ve/sunrpc: Prohibit mounting rpc_pipefs in CT without nfsd feature

[Nikita Yushchenko]

From: Pavel Tikhomirov <ptikhomirov at virtuozzo.com>

We need rpc_pipefs for nfs server, but it breaks criu migration as
opened /var/lib/nfs/rpc_pipefs/nfs/clntX files are not supported yet.
Thus only allow mounting rpc_pipefs if CT has "--features nfsd:on".

Note: no additional check for ve_is_super() required because
VE0 has all features enabled:

struct ve_struct ve0 = {
...
	.features	= -1,

crash> p -x ve0.features
$2 = 0xffffffffffffffff

https://jira.sw.ru/browse/PSBM-87836
Signed-off-by: Pavel Tikhomirov <ptikhomirov at virtuozzo.com>

(cherry-picked from vz8 commit 05ed72031c5f ("ve/sunrpc: Prohibit
mounting rpc_pipefs in CT without nfsd feature"))

Signed-off-by: Nikita Yushchenko <nikita.yushchenko at virtuozzo.com>
---
 net/sunrpc/rpc_pipe.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/net/sunrpc/rpc_pipe.c b/net/sunrpc/rpc_pipe.c
index 37d08af10d30..c6f227b8fb8d 100644
--- a/net/sunrpc/rpc_pipe.c
+++ b/net/sunrpc/rpc_pipe.c
@@ -33,6 +33,9 @@
 #include <linux/nsproxy.h>
 #include <linux/notifier.h>
 
+#include <uapi/linux/vzcalluser.h>
+#include <linux/ve.h>
+
 #include "netns.h"
 #include "sunrpc.h"
 
@@ -1435,6 +1438,9 @@ static const struct fs_context_operations rpc_fs_context_ops = {
 
 static int rpc_init_fs_context(struct fs_context *fc)
 {
+	if (!(get_exec_env()->features & VE_FEATURE_NFSD))
+		return -ENODEV;
+
 	put_user_ns(fc->user_ns);
 	fc->user_ns = get_user_ns(fc->net_ns->user_ns);
 	fc->ops = &rpc_fs_context_ops;
-- 
2.30.2