blob: e747b3d720eeb1594737ed8b7a7c0ef15fd5166b [file] [log] [blame]
Al Viroefb170c2014-08-07 08:39:04 -04001#include <linux/fs.h>
Al Viro59eda0e2015-01-10 17:53:21 -05002#include <linux/sched.h>
Al Viroefb170c2014-08-07 08:39:04 -04003#include <linux/slab.h>
Al Viro8fa1f1c2014-05-21 18:22:52 -04004#include "internal.h"
Al Viroefb170c2014-08-07 08:39:04 -04005#include "mount.h"
6
Al Viroefb170c2014-08-07 08:39:04 -04007static DEFINE_SPINLOCK(pin_lock);
8
Al Viroefb170c2014-08-07 08:39:04 -04009void pin_remove(struct fs_pin *pin)
10{
11 spin_lock(&pin_lock);
Eric W. Biederman820f9f12015-04-02 16:35:48 -050012 hlist_del_init(&pin->m_list);
13 hlist_del_init(&pin->s_list);
Al Viroefb170c2014-08-07 08:39:04 -040014 spin_unlock(&pin_lock);
Al Viro59eda0e2015-01-10 17:53:21 -050015 spin_lock_irq(&pin->wait.lock);
16 pin->done = 1;
17 wake_up_locked(&pin->wait);
18 spin_unlock_irq(&pin->wait.lock);
Al Viroefb170c2014-08-07 08:39:04 -040019}
20
Al Virofdab6842015-01-11 10:57:27 -050021void pin_insert_group(struct fs_pin *pin, struct vfsmount *m, struct hlist_head *p)
Al Viroefb170c2014-08-07 08:39:04 -040022{
23 spin_lock(&pin_lock);
Al Virofdab6842015-01-11 10:57:27 -050024 if (p)
25 hlist_add_head(&pin->s_list, p);
Al Viroefb170c2014-08-07 08:39:04 -040026 hlist_add_head(&pin->m_list, &real_mount(m)->mnt_pins);
27 spin_unlock(&pin_lock);
28}
29
Al Virofdab6842015-01-11 10:57:27 -050030void pin_insert(struct fs_pin *pin, struct vfsmount *m)
31{
32 pin_insert_group(pin, m, &m->mnt_sb->s_pins);
33}
34
Al Viro59eda0e2015-01-10 17:53:21 -050035void pin_kill(struct fs_pin *p)
36{
Ingo Molnarac6424b2017-06-20 12:06:13 +020037 wait_queue_entry_t wait;
Al Viro59eda0e2015-01-10 17:53:21 -050038
39 if (!p) {
40 rcu_read_unlock();
41 return;
42 }
43 init_wait(&wait);
44 spin_lock_irq(&p->wait.lock);
45 if (likely(!p->done)) {
46 p->done = -1;
47 spin_unlock_irq(&p->wait.lock);
48 rcu_read_unlock();
49 p->kill(p);
50 return;
51 }
52 if (p->done > 0) {
53 spin_unlock_irq(&p->wait.lock);
54 rcu_read_unlock();
55 return;
56 }
57 __add_wait_queue(&p->wait, &wait);
58 while (1) {
59 set_current_state(TASK_UNINTERRUPTIBLE);
60 spin_unlock_irq(&p->wait.lock);
61 rcu_read_unlock();
62 schedule();
63 rcu_read_lock();
Ingo Molnar2055da92017-06-20 12:06:46 +020064 if (likely(list_empty(&wait.entry)))
Al Viro59eda0e2015-01-10 17:53:21 -050065 break;
66 /* OK, we know p couldn't have been freed yet */
67 spin_lock_irq(&p->wait.lock);
68 if (p->done > 0) {
69 spin_unlock_irq(&p->wait.lock);
70 break;
71 }
72 }
73 rcu_read_unlock();
74}
75
Al Viro8fa1f1c2014-05-21 18:22:52 -040076void mnt_pin_kill(struct mount *m)
Al Viroefb170c2014-08-07 08:39:04 -040077{
78 while (1) {
79 struct hlist_node *p;
Al Viroefb170c2014-08-07 08:39:04 -040080 rcu_read_lock();
Al Viro8fa1f1c2014-05-21 18:22:52 -040081 p = ACCESS_ONCE(m->mnt_pins.first);
Al Viroefb170c2014-08-07 08:39:04 -040082 if (!p) {
83 rcu_read_unlock();
84 break;
85 }
Al Viro59eda0e2015-01-10 17:53:21 -050086 pin_kill(hlist_entry(p, struct fs_pin, m_list));
Al Viroefb170c2014-08-07 08:39:04 -040087 }
88}
89
Al Virofdab6842015-01-11 10:57:27 -050090void group_pin_kill(struct hlist_head *p)
Al Viroefb170c2014-08-07 08:39:04 -040091{
92 while (1) {
Al Virofdab6842015-01-11 10:57:27 -050093 struct hlist_node *q;
Al Viroefb170c2014-08-07 08:39:04 -040094 rcu_read_lock();
Al Virofdab6842015-01-11 10:57:27 -050095 q = ACCESS_ONCE(p->first);
96 if (!q) {
Al Viroefb170c2014-08-07 08:39:04 -040097 rcu_read_unlock();
98 break;
99 }
Al Viro59eda0e2015-01-10 17:53:21 -0500100 pin_kill(hlist_entry(q, struct fs_pin, s_list));
Al Viroefb170c2014-08-07 08:39:04 -0400101 }
102}