linux/fs/nfs_common/grace.c

// SPDX-License-Identifier: GPL-2.0-only
/*
 * 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>
#include <linux/filelock.h>

static unsigned 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)
{ … }
EXPORT_SYMBOL_GPL(…);

/**
 * 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)
{ … }
EXPORT_SYMBOL_GPL(…);

static bool
__state_in_grace(struct net *net, bool open)
{ … }

/**
 * locks_in_grace
 * @net: network namespace
 *
 * 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.
 */
bool locks_in_grace(struct net *net)
{ … }
EXPORT_SYMBOL_GPL(…);

bool opens_in_grace(struct net *net)
{ … }
EXPORT_SYMBOL_GPL(…);

static int __net_init
grace_init_net(struct net *net)
{ … }

static void __net_exit
grace_exit_net(struct net *net)
{ … }

static struct pernet_operations grace_net_ops = …;

static int __init
init_grace(void)
{ … }

static void __exit
exit_grace(void)
{ … }

MODULE_AUTHOR(…) …;
MODULE_DESCRIPTION(…) …;
MODULE_LICENSE(…) …;
module_init(…) …
module_exit(…)