[PATCH 2/2] NFS: Add a module parameter to set nfs_mountpoint_expiry_timeout

[trondmy@kernel.org]

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

Setting nfs_mountpoint_expiry_timeout() to a negative value stops
mountpoint expiration, while setting it to a positive value restarts
the scheduler.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
---
 fs/nfs/namespace.c | 35 +++++++++++++++++++++++++++++++++++
 1 file changed, 35 insertions(+)

diff --git a/fs/nfs/namespace.c b/fs/nfs/namespace.c
index 50b162dd88f5..4c02f0e00620 100644
--- a/fs/nfs/namespace.c
+++ b/fs/nfs/namespace.c
@@ -311,3 +311,38 @@ int nfs_submount(struct fs_context *fc, struct nfs_server *server)
 	return nfs_do_submount(fc);
 }
 EXPORT_SYMBOL_GPL(nfs_submount);
+
+static int param_set_nfs_timeout(const char *val, const struct kernel_param *kp)
+{
+	long num;
+	int ret;
+
+	if (!val)
+		return -EINVAL;
+	ret = kstrtol(val, 0, &num);
+	if (ret)
+		return -EINVAL;
+	if (num >= 0) {
+		num *= HZ;
+		if (num > INT_MAX)
+			num = INT_MAX;
+		*((int *)kp->arg) = num;
+		if (!list_empty(&nfs_automount_list))
+			mod_delayed_work(system_wq, &nfs_automount_task, num);
+	} else {
+		*((int *)kp->arg) = -1;
+		cancel_delayed_work(&nfs_automount_task);
+	}
+	return 0;
+}
+
+static const struct kernel_param_ops param_ops_nfs_timeout = {
+	.set = param_set_nfs_timeout,
+	.get = param_get_uint,
+};
+#define param_check_nfs_timeout(name, p) __param_check(name, p, int);
+
+module_param(nfs_mountpoint_expiry_timeout, nfs_timeout, 0644);
+MODULE_PARM_DESC(nfs_mountpoint_expiry_timeout,
+		"Set the NFS automounted mountpoint timeout value."
+		"Negative values turn expiration off.");
-- 
2.25.1