--- /dev/null
+From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
+From: Olga Kornievskaia <kolga@netapp.com>
+Date: Wed, 16 Mar 2022 18:24:26 -0400
+Subject: [PATCH] NFSv4.1 provide mount option to toggle trunking discovery
+
+Introduce a new mount option -- trunkdiscovery,notrunkdiscovery -- to
+toggle whether or not the client will engage in actively discovery
+of trunking locations.
+
+v2 make notrunkdiscovery default
+
+Signed-off-by: Olga Kornievskaia <kolga@netapp.com>
+Fixes: 1976b2b31462 ("NFSv4.1 query for fs_location attr on a new file system")
+Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
+(cherry picked from commit a43bf604446414103b7535f38e739b65601c4fb2)
+Signed-off-by: Thomas Lamprecht <t.lamprecht@proxmox.com>
+---
+ fs/nfs/client.c | 3 ++-
+ fs/nfs/fs_context.c | 8 ++++++++
+ include/linux/nfs_fs_sb.h | 1 +
+ 3 files changed, 11 insertions(+), 1 deletion(-)
+
+diff --git a/fs/nfs/client.c b/fs/nfs/client.c
+index 090b16890e3d..f303e96ce165 100644
+--- a/fs/nfs/client.c
++++ b/fs/nfs/client.c
+@@ -861,7 +861,8 @@ int nfs_probe_fsinfo(struct nfs_server *server, struct nfs_fh *mntfh, struct nfs
+ }
+
+ if (clp->rpc_ops->discover_trunking != NULL &&
+- (server->caps & NFS_CAP_FS_LOCATIONS)) {
++ (server->caps & NFS_CAP_FS_LOCATIONS &&
++ (server->flags & NFS_MOUNT_TRUNK_DISCOVERY))) {
+ error = clp->rpc_ops->discover_trunking(server, mntfh);
+ if (error < 0)
+ return error;
+diff --git a/fs/nfs/fs_context.c b/fs/nfs/fs_context.c
+index 0d444a90f513..da5217abc2e5 100644
+--- a/fs/nfs/fs_context.c
++++ b/fs/nfs/fs_context.c
+@@ -79,6 +79,7 @@ enum nfs_param {
+ Opt_source,
+ Opt_tcp,
+ Opt_timeo,
++ Opt_trunkdiscovery,
+ Opt_udp,
+ Opt_v,
+ Opt_vers,
+@@ -179,6 +180,7 @@ static const struct fs_parameter_spec nfs_fs_parameters[] = {
+ fsparam_string("source", Opt_source),
+ fsparam_flag ("tcp", Opt_tcp),
+ fsparam_u32 ("timeo", Opt_timeo),
++ fsparam_flag_no("trunkdiscovery", Opt_trunkdiscovery),
+ fsparam_flag ("udp", Opt_udp),
+ fsparam_flag ("v2", Opt_v),
+ fsparam_flag ("v3", Opt_v),
+@@ -528,6 +530,12 @@ static int nfs_fs_context_parse_param(struct fs_context *fc,
+ else
+ ctx->flags &= ~NFS_MOUNT_NOCTO;
+ break;
++ case Opt_trunkdiscovery:
++ if (result.negated)
++ ctx->flags &= ~NFS_MOUNT_TRUNK_DISCOVERY;
++ else
++ ctx->flags |= NFS_MOUNT_TRUNK_DISCOVERY;
++ break;
+ case Opt_ac:
+ if (result.negated)
+ ctx->flags |= NFS_MOUNT_NOAC;
+diff --git a/include/linux/nfs_fs_sb.h b/include/linux/nfs_fs_sb.h
+index 9a6e70ccde56..10c347416dd2 100644
+--- a/include/linux/nfs_fs_sb.h
++++ b/include/linux/nfs_fs_sb.h
+@@ -156,6 +156,7 @@ struct nfs_server {
+ #define NFS_MOUNT_SOFTREVAL 0x800000
+ #define NFS_MOUNT_WRITE_EAGER 0x01000000
+ #define NFS_MOUNT_WRITE_WAIT 0x02000000
++#define NFS_MOUNT_TRUNK_DISCOVERY 0x04000000
+
+ unsigned int fattr_valid; /* Valid attributes */
+ unsigned int caps; /* server capabilities */