3 files changed, 33 insertions, 0 deletions
diff --git a/fs/nfs/idmap.c b/fs/nfs/idmap.c
index ffb8df9..821edd3 100644
--- a/fs/nfs/idmap.c
+++ b/fs/nfs/idmap.c
@@ -54,7 +54,11 @@
 
 #define IDMAP_HASH_SZ          128
 
+/* Default cache timeout is 10 minutes */
+unsigned int nfs_idmap_cache_timeout = 600 * HZ;
+
 struct idmap_hashent {
+	unsigned long ih_expires;
 	__u32 ih_id;
 	int ih_namelen;
 	char ih_name[IDMAP_NAMESZ];
@@ -149,6 +153,8 @@ idmap_lookup_name(struct idmap_hashtable *h, const char *name, size_t len)
 
 	if (he->ih_namelen != len || memcmp(he->ih_name, name, len) != 0)
 		return NULL;
+	if (time_after(jiffies, he->ih_expires))
+		return NULL;
 	return he;
 }
 
@@ -164,6 +170,8 @@ idmap_lookup_id(struct idmap_hashtable *h, __u32 id)
 	struct idmap_hashent *he = idmap_id_hash(h, id);
 	if (he->ih_id != id || he->ih_namelen == 0)
 		return NULL;
+	if (time_after(jiffies, he->ih_expires))
+		return NULL;
 	return he;
 }
 
@@ -192,6 +200,7 @@ idmap_update_entry(struct idmap_hashent *he, const char *name,
 	memcpy(he->ih_name, name, namelen);
 	he->ih_name[namelen] = '\0';
 	he->ih_namelen = namelen;
+	he->ih_expires = jiffies + nfs_idmap_cache_timeout;
 }
 
 /*
diff --git a/fs/nfs/inode.c b/fs/nfs/inode.c
index 4625479..e7bd0d9 100644
--- a/fs/nfs/inode.c
+++ b/fs/nfs/inode.c
@@ -2050,6 +2050,20 @@ static int param_set_port(const char *val, struct kernel_param *kp)
 module_param_call(callback_tcpport, param_set_port, param_get_int,
 		 &nfs_callback_set_tcpport, 0644);
 
+static int param_set_idmap_timeout(const char *val, struct kernel_param *kp)
+{
+	char *endp;
+	int num = simple_strtol(val, &endp, 0);
+	int jif = num * HZ;
+	if (endp == val || *endp || num < 0 || jif < num)
+		return -EINVAL;
+	*((int *)kp->arg) = jif;
+	return 0;
+}
+
+module_param_call(idmap_cache_timeout, param_set_idmap_timeout, param_get_int,
+		 &nfs_idmap_cache_timeout, 0644);
+
 #define nfs4_init_once(nfsi) \
 	do { \
 		INIT_LIST_HEAD(&(nfsi)->open_states); \
diff --git a/fs/nfs/sysctl.c b/fs/nfs/sysctl.c
index fdc64b5..4c486eb 100644
--- a/fs/nfs/sysctl.c
+++ b/fs/nfs/sysctl.c
@@ -11,6 +11,7 @@
 #include <linux/sysctl.h>
 #include <linux/module.h>
 #include <linux/nfs4.h>
+#include <linux/nfs_idmap.h>
 
 #include "callback.h"
 
@@ -35,6 +36,15 @@ static ctl_table nfs_cb_sysctls[] = {
 		.extra1 = (int *)&nfs_set_port_min,
 		.extra2 = (int *)&nfs_set_port_max,
 	},
+	{
+		.ctl_name = CTL_UNNUMBERED,
+		.procname = "idmap_cache_timeout",
+		.data = &nfs_idmap_cache_timeout,
+		.maxlen = sizeof(int),
+		.mode = 0644,
+		.proc_handler = &proc_dointvec_jiffies,
+		.strategy = &sysctl_jiffies,
+	},
 #endif
 	{ .ctl_name = 0 }
 };