[PATCH v3 1/8] lockd: move lockd's grace period handling into its own module

[Jeff Layton <jlayton@primarydata.com>]

Currently, all of the grace period handling is part of lockd. Eventually
though we'd like to be able to build v4-only servers, at which point
we'll need to put all of this elsewhere.

Move the code itself into fs/nfs_common and have it build a grace.ko
module. Then, rejigger the Kconfig options so that both nfsd and lockd
enable it automatically.

Signed-off-by: Jeff Layton <jlayton@primarydata.com>
---
 fs/Kconfig              |   6 ++-
 fs/lockd/Makefile       |   2 +-
 fs/lockd/grace.c        |  65 ----------------------------
 fs/lockd/netns.h        |   1 -
 fs/lockd/svc.c          |   1 -
 fs/nfs_common/Makefile  |   3 +-
 fs/nfs_common/grace.c   | 113 ++++++++++++++++++++++++++++++++++++++++++++++++
 fs/nfsd/Kconfig         |   1 +
 include/linux/proc_fs.h |   2 +
 9 files changed, 124 insertions(+), 70 deletions(-)
 delete mode 100644 fs/lockd/grace.c
 create mode 100644 fs/nfs_common/grace.c

diff --git a/fs/Kconfig b/fs/Kconfig
index 312393f32948..db5dc1598716 100644
--- a/fs/Kconfig
+++ b/fs/Kconfig
@@ -233,9 +233,13 @@ if NETWORK_FILESYSTEMS
 source "fs/nfs/Kconfig"
 source "fs/nfsd/Kconfig"
 
+config GRACE_PERIOD
+	tristate
+
 config LOCKD
 	tristate
 	depends on FILE_LOCKING
+	select GRACE_PERIOD
 
 config LOCKD_V4
 	bool
@@ -249,7 +253,7 @@ config NFS_ACL_SUPPORT
 
 config NFS_COMMON
 	bool
-	depends on NFSD || NFS_FS
+	depends on NFSD || NFS_FS || LOCKD
 	default y
 
 source "net/sunrpc/Kconfig"
diff --git a/fs/lockd/Makefile b/fs/lockd/Makefile
index ca58d64374ca..6a0b351ce30e 100644
--- a/fs/lockd/Makefile
+++ b/fs/lockd/Makefile
@@ -5,6 +5,6 @@
 obj-$(CONFIG_LOCKD) += lockd.o
 
 lockd-objs-y := clntlock.o clntproc.o clntxdr.o host.o svc.o svclock.o \
-	        svcshare.o svcproc.o svcsubs.o mon.o xdr.o grace.o
+	        svcshare.o svcproc.o svcsubs.o mon.o xdr.o
 lockd-objs-$(CONFIG_LOCKD_V4) += clnt4xdr.o xdr4.o svc4proc.o
 lockd-objs		      := $(lockd-objs-y)
diff --git a/fs/lockd/grace.c b/fs/lockd/grace.c
deleted file mode 100644
index 6d1ee7204c88..000000000000
--- a/fs/lockd/grace.c
+++ /dev/null
@@ -1,65 +0,0 @@
-/*
- * Common code for control of lockd and nfsv4 grace periods.
- */
-
-#include <linux/module.h>
-#include <linux/lockd/bind.h>
-#include <net/net_namespace.h>
-
-#include "netns.h"
-
-static DEFINE_SPINLOCK(grace_lock);
-
-/**
- * locks_start_grace
- * @lm: who this grace period is for
- *
- * A grace period is a period during which locks should not be given
- * out.  Currently grace periods are only enforced by the two lock
- * managers (lockd and nfsd), using the locks_in_grace() function to
- * check when they are in a grace period.
- *
- * This function is called to start a grace period.
- */
-void locks_start_grace(struct net *net, struct lock_manager *lm)
-{
-	struct lockd_net *ln = net_generic(net, lockd_net_id);
-
-	spin_lock(&grace_lock);
-	list_add(&lm->list, &ln->grace_list);
-	spin_unlock(&grace_lock);
-}
-EXPORT_SYMBOL_GPL(locks_start_grace);
-
-/**
- * locks_end_grace
- * @lm: who this grace period is for
- *
- * Call this function to state that the given lock manager is ready to
- * resume regular locking.  The grace period will not end until all lock
- * managers that called locks_start_grace() also call locks_end_grace().
- * Note that callers count on it being safe to call this more than once,
- * and the second call should be a no-op.
- */
-void locks_end_grace(struct lock_manager *lm)
-{
-	spin_lock(&grace_lock);
-	list_del_init(&lm->list);
-	spin_unlock(&grace_lock);
-}
-EXPORT_SYMBOL_GPL(locks_end_grace);
-
-/**
- * locks_in_grace
- *
- * Lock managers call this function to determine when it is OK for them
- * to answer ordinary lock requests, and when they should accept only
- * lock reclaims.
- */
-int locks_in_grace(struct net *net)
-{
-	struct lockd_net *ln = net_generic(net, lockd_net_id);
-
-	return !list_empty(&ln->grace_list);
-}
-EXPORT_SYMBOL_GPL(locks_in_grace);
diff --git a/fs/lockd/netns.h b/fs/lockd/netns.h
index 5010b55628b4..097bfa3adb1c 100644
--- a/fs/lockd/netns.h
+++ b/fs/lockd/netns.h
@@ -11,7 +11,6 @@ struct lockd_net {
 
 	struct delayed_work grace_period_end;
 	struct lock_manager lockd_manager;
-	struct list_head grace_list;
 
 	spinlock_t nsm_clnt_lock;
 	unsigned int nsm_users;
diff --git a/fs/lockd/svc.c b/fs/lockd/svc.c
index 8f27c93f8d2e..3599c9ca28ae 100644
--- a/fs/lockd/svc.c
+++ b/fs/lockd/svc.c
@@ -583,7 +583,6 @@ static int lockd_init_net(struct net *net)
 	struct lockd_net *ln = net_generic(net, lockd_net_id);
 
 	INIT_DELAYED_WORK(&ln->grace_period_end, grace_ender);
-	INIT_LIST_HEAD(&ln->grace_list);
 	spin_lock_init(&ln->nsm_clnt_lock);
 	return 0;
 }
diff --git a/fs/nfs_common/Makefile b/fs/nfs_common/Makefile
index f689ed82af3a..d153ca3ea577 100644
--- a/fs/nfs_common/Makefile
+++ b/fs/nfs_common/Makefile
@@ -3,5 +3,6 @@
 #
 
 obj-$(CONFIG_NFS_ACL_SUPPORT) += nfs_acl.o
-
 nfs_acl-objs := nfsacl.o
+
+obj-$(CONFIG_GRACE_PERIOD) += grace.o
diff --git a/fs/nfs_common/grace.c b/fs/nfs_common/grace.c
new file mode 100644
index 000000000000..ae6e58ea4de5
--- /dev/null
+++ b/fs/nfs_common/grace.c
@@ -0,0 +1,113 @@
+/*
+ * Common code for control of lockd and nfsv4 grace periods.
+ *
+ * Transplanted from lockd code
+ */
+
+#include <linux/module.h>
+#include <net/net_namespace.h>
+#include <net/netns/generic.h>
+#include <linux/fs.h>
+
+static int grace_net_id;
+static DEFINE_SPINLOCK(grace_lock);
+
+/**
+ * locks_start_grace
+ * @net: net namespace that this lock manager belongs to
+ * @lm: who this grace period is for
+ *
+ * A grace period is a period during which locks should not be given
+ * out.  Currently grace periods are only enforced by the two lock
+ * managers (lockd and nfsd), using the locks_in_grace() function to
+ * check when they are in a grace period.
+ *
+ * This function is called to start a grace period.
+ */
+void
+locks_start_grace(struct net *net, struct lock_manager *lm)
+{
+	struct list_head *grace_list = net_generic(net, grace_net_id);
+
+	spin_lock(&grace_lock);
+	list_add(&lm->list, grace_list);
+	spin_unlock(&grace_lock);
+}
+EXPORT_SYMBOL_GPL(locks_start_grace);
+
+/**
+ * locks_end_grace
+ * @net: net namespace that this lock manager belongs to
+ * @lm: who this grace period is for
+ *
+ * Call this function to state that the given lock manager is ready to
+ * resume regular locking.  The grace period will not end until all lock
+ * managers that called locks_start_grace() also call locks_end_grace().
+ * Note that callers count on it being safe to call this more than once,
+ * and the second call should be a no-op.
+ */
+void
+locks_end_grace(struct lock_manager *lm)
+{
+	spin_lock(&grace_lock);
+	list_del_init(&lm->list);
+	spin_unlock(&grace_lock);
+}
+EXPORT_SYMBOL_GPL(locks_end_grace);
+
+/**
+ * locks_in_grace
+ *
+ * Lock managers call this function to determine when it is OK for them
+ * to answer ordinary lock requests, and when they should accept only
+ * lock reclaims.
+ */
+int
+locks_in_grace(struct net *net)
+{
+	struct list_head *grace_list = net_generic(net, grace_net_id);
+
+	return !list_empty(grace_list);
+}
+EXPORT_SYMBOL_GPL(locks_in_grace);
+
+static int __net_init
+grace_init_net(struct net *net)
+{
+	struct list_head *grace_list = net_generic(net, grace_net_id);
+
+	INIT_LIST_HEAD(grace_list);
+	return 0;
+}
+
+static void __net_exit
+grace_exit_net(struct net *net)
+{
+	struct list_head *grace_list = net_generic(net, grace_net_id);
+
+	BUG_ON(!list_empty(grace_list));
+}
+
+static struct pernet_operations grace_net_ops = {
+	.init = grace_init_net,
+	.exit = grace_exit_net,
+	.id   = &grace_net_id,
+	.size = sizeof(struct list_head),
+};
+
+static int __init
+init_grace(void)
+{
+	return register_pernet_subsys(&grace_net_ops);
+}
+
+static void __exit
+exit_grace(void)
+{
+	unregister_pernet_subsys(&grace_net_ops);
+}
+
+MODULE_AUTHOR("Jeff Layton <jlayton@primarydata.com>");
+MODULE_LICENSE("GPL");
+module_init(init_grace)
+module_exit(exit_grace)
diff --git a/fs/nfsd/Kconfig b/fs/nfsd/Kconfig
index f994e750e0d1..4fa98764de21 100644
--- a/fs/nfsd/Kconfig
+++ b/fs/nfsd/Kconfig
@@ -71,6 +71,7 @@ config NFSD_V4
 	select FS_POSIX_ACL
 	select SUNRPC_GSS
 	select CRYPTO
+	select GRACE_PERIOD
 	help
 	  This option enables support in your system's NFS server for
 	  version 4 of the NFS protocol (RFC 3530).
diff --git a/include/linux/proc_fs.h b/include/linux/proc_fs.h
index 9d117f61d976..b97bf2ef996e 100644
--- a/include/linux/proc_fs.h
+++ b/include/linux/proc_fs.h
@@ -74,6 +74,8 @@ static inline int remove_proc_subtree(const char *name, struct proc_dir_entry *p
 
 #endif /* CONFIG_PROC_FS */
 
+struct net;
+
 static inline struct proc_dir_entry *proc_net_mkdir(
 	struct net *net, const char *name, struct proc_dir_entry *parent)
 {
-- 
1.9.3