Commit | Line | Data |
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09c434b8 | 1 | // SPDX-License-Identifier: GPL-2.0-only |
af558e33 BF |
2 | /* |
3 | * Common code for control of lockd and nfsv4 grace periods. | |
f7790029 JL |
4 | * |
5 | * Transplanted from lockd code | |
af558e33 BF |
6 | */ |
7 | ||
8 | #include <linux/module.h> | |
db9c4553 | 9 | #include <net/net_namespace.h> |
f7790029 JL |
10 | #include <net/netns/generic.h> |
11 | #include <linux/fs.h> | |
5970e15d | 12 | #include <linux/filelock.h> |
db9c4553 | 13 | |
c7d03a00 | 14 | static unsigned int grace_net_id; |
af558e33 BF |
15 | static DEFINE_SPINLOCK(grace_lock); |
16 | ||
17 | /** | |
18 | * locks_start_grace | |
f7790029 | 19 | * @net: net namespace that this lock manager belongs to |
af558e33 BF |
20 | * @lm: who this grace period is for |
21 | * | |
22 | * A grace period is a period during which locks should not be given | |
23 | * out. Currently grace periods are only enforced by the two lock | |
24 | * managers (lockd and nfsd), using the locks_in_grace() function to | |
25 | * check when they are in a grace period. | |
26 | * | |
27 | * This function is called to start a grace period. | |
28 | */ | |
f7790029 JL |
29 | void |
30 | locks_start_grace(struct net *net, struct lock_manager *lm) | |
af558e33 | 31 | { |
f7790029 | 32 | struct list_head *grace_list = net_generic(net, grace_net_id); |
db9c4553 | 33 | |
af558e33 | 34 | spin_lock(&grace_lock); |
81833de1 VA |
35 | if (list_empty(&lm->list)) |
36 | list_add(&lm->list, grace_list); | |
37 | else | |
38 | WARN(1, "double list_add attempt detected in net %x %s\n", | |
39 | net->ns.inum, (net == &init_net) ? "(init_net)" : ""); | |
af558e33 BF |
40 | spin_unlock(&grace_lock); |
41 | } | |
42 | EXPORT_SYMBOL_GPL(locks_start_grace); | |
43 | ||
44 | /** | |
45 | * locks_end_grace | |
46 | * @lm: who this grace period is for | |
47 | * | |
48 | * Call this function to state that the given lock manager is ready to | |
49 | * resume regular locking. The grace period will not end until all lock | |
50 | * managers that called locks_start_grace() also call locks_end_grace(). | |
51 | * Note that callers count on it being safe to call this more than once, | |
52 | * and the second call should be a no-op. | |
53 | */ | |
f7790029 JL |
54 | void |
55 | locks_end_grace(struct lock_manager *lm) | |
af558e33 BF |
56 | { |
57 | spin_lock(&grace_lock); | |
58 | list_del_init(&lm->list); | |
59 | spin_unlock(&grace_lock); | |
60 | } | |
61 | EXPORT_SYMBOL_GPL(locks_end_grace); | |
62 | ||
003278e4 | 63 | static bool |
c87fb4a3 | 64 | __state_in_grace(struct net *net, bool open) |
af558e33 | 65 | { |
f7790029 | 66 | struct list_head *grace_list = net_generic(net, grace_net_id); |
c87fb4a3 | 67 | struct lock_manager *lm; |
db9c4553 | 68 | |
c87fb4a3 BF |
69 | if (!open) |
70 | return !list_empty(grace_list); | |
71 | ||
4a9d81ca | 72 | spin_lock(&grace_lock); |
c87fb4a3 | 73 | list_for_each_entry(lm, grace_list, list) { |
4a9d81ca CL |
74 | if (lm->block_opens) { |
75 | spin_unlock(&grace_lock); | |
c87fb4a3 | 76 | return true; |
4a9d81ca | 77 | } |
c87fb4a3 | 78 | } |
4a9d81ca | 79 | spin_unlock(&grace_lock); |
c87fb4a3 BF |
80 | return false; |
81 | } | |
82 | ||
809d4fcf CL |
83 | /** |
84 | * locks_in_grace | |
5823e400 | 85 | * @net: network namespace |
809d4fcf CL |
86 | * |
87 | * Lock managers call this function to determine when it is OK for them | |
88 | * to answer ordinary lock requests, and when they should accept only | |
89 | * lock reclaims. | |
90 | */ | |
003278e4 | 91 | bool locks_in_grace(struct net *net) |
c87fb4a3 | 92 | { |
003278e4 | 93 | return __state_in_grace(net, false); |
af558e33 BF |
94 | } |
95 | EXPORT_SYMBOL_GPL(locks_in_grace); | |
f7790029 | 96 | |
003278e4 | 97 | bool opens_in_grace(struct net *net) |
c87fb4a3 | 98 | { |
003278e4 | 99 | return __state_in_grace(net, true); |
c87fb4a3 BF |
100 | } |
101 | EXPORT_SYMBOL_GPL(opens_in_grace); | |
102 | ||
f7790029 JL |
103 | static int __net_init |
104 | grace_init_net(struct net *net) | |
105 | { | |
106 | struct list_head *grace_list = net_generic(net, grace_net_id); | |
107 | ||
108 | INIT_LIST_HEAD(grace_list); | |
109 | return 0; | |
110 | } | |
111 | ||
112 | static void __net_exit | |
113 | grace_exit_net(struct net *net) | |
114 | { | |
115 | struct list_head *grace_list = net_generic(net, grace_net_id); | |
116 | ||
b8722857 VA |
117 | WARN_ONCE(!list_empty(grace_list), |
118 | "net %x %s: grace_list is not empty\n", | |
119 | net->ns.inum, __func__); | |
f7790029 JL |
120 | } |
121 | ||
122 | static struct pernet_operations grace_net_ops = { | |
123 | .init = grace_init_net, | |
124 | .exit = grace_exit_net, | |
125 | .id = &grace_net_id, | |
126 | .size = sizeof(struct list_head), | |
127 | }; | |
128 | ||
129 | static int __init | |
130 | init_grace(void) | |
131 | { | |
132 | return register_pernet_subsys(&grace_net_ops); | |
133 | } | |
134 | ||
135 | static void __exit | |
136 | exit_grace(void) | |
137 | { | |
138 | unregister_pernet_subsys(&grace_net_ops); | |
139 | } | |
140 | ||
141 | MODULE_AUTHOR("Jeff Layton <jlayton@primarydata.com>"); | |
142 | MODULE_LICENSE("GPL"); | |
143 | module_init(init_grace) | |
144 | module_exit(exit_grace) |