From f7790029655f79cdcee4fa7c7884e0c2795ebebe Mon Sep 17 00:00:00 2001 From: Jeff Layton Date: Fri, 12 Sep 2014 16:40:20 -0400 Subject: lockd: move lockd's grace period handling into its own module 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 --- fs/nfs_common/Makefile | 3 +- fs/nfs_common/grace.c | 113 +++++++++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 115 insertions(+), 1 deletion(-) create mode 100644 fs/nfs_common/grace.c (limited to 'fs/nfs_common') 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 +#include +#include +#include + +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 "); +MODULE_LICENSE("GPL"); +module_init(init_grace) +module_exit(exit_grace) -- cgit v1.2.3-59-g8ed1b