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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-27 10:05:51 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-27 10:05:51 +0000 |
commit | 5d1646d90e1f2cceb9f0828f4b28318cd0ec7744 (patch) | |
tree | a94efe259b9009378be6d90eb30d2b019d95c194 /fs/nfs_common/grace.c | |
parent | Initial commit. (diff) | |
download | linux-upstream/5.10.209.tar.xz linux-upstream/5.10.209.zip |
Adding upstream version 5.10.209.upstream/5.10.209upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'fs/nfs_common/grace.c')
-rw-r--r-- | fs/nfs_common/grace.c | 143 |
1 files changed, 143 insertions, 0 deletions
diff --git a/fs/nfs_common/grace.c b/fs/nfs_common/grace.c new file mode 100644 index 000000000..26f2a50ec --- /dev/null +++ b/fs/nfs_common/grace.c @@ -0,0 +1,143 @@ +// 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> + +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) +{ + struct list_head *grace_list = net_generic(net, grace_net_id); + + spin_lock(&grace_lock); + if (list_empty(&lm->list)) + list_add(&lm->list, grace_list); + else + WARN(1, "double list_add attempt detected in net %x %s\n", + net->ns.inum, (net == &init_net) ? "(init_net)" : ""); + 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); + +static bool +__state_in_grace(struct net *net, bool open) +{ + struct list_head *grace_list = net_generic(net, grace_net_id); + struct lock_manager *lm; + + if (!open) + return !list_empty(grace_list); + + spin_lock(&grace_lock); + list_for_each_entry(lm, grace_list, list) { + if (lm->block_opens) { + spin_unlock(&grace_lock); + return true; + } + } + spin_unlock(&grace_lock); + return false; +} + +/** + * 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. + */ +bool locks_in_grace(struct net *net) +{ + return __state_in_grace(net, false); +} +EXPORT_SYMBOL_GPL(locks_in_grace); + +bool opens_in_grace(struct net *net) +{ + return __state_in_grace(net, true); +} +EXPORT_SYMBOL_GPL(opens_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); + + WARN_ONCE(!list_empty(grace_list), + "net %x %s: grace_list is not empty\n", + net->ns.inum, __func__); +} + +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) |