[mirror_ubuntu-artful-kernel.git] / fs / fs_pin.c

#include <linux/fs.h>
#include <linux/sched.h>
#include <linux/slab.h>
#include "internal.h"
#include "mount.h"

static DEFINE_SPINLOCK(pin_lock);

void pin_remove(struct fs_pin *pin)
{
	spin_lock(&pin_lock);
	hlist_del_init(&pin->m_list);
	hlist_del_init(&pin->s_list);
	spin_unlock(&pin_lock);
	spin_lock_irq(&pin->wait.lock);
	pin->done = 1;
	wake_up_locked(&pin->wait);
	spin_unlock_irq(&pin->wait.lock);
}

void pin_insert_group(struct fs_pin *pin, struct vfsmount *m, struct hlist_head *p)
{
	spin_lock(&pin_lock);
	if (p)
		hlist_add_head(&pin->s_list, p);
	hlist_add_head(&pin->m_list, &real_mount(m)->mnt_pins);
	spin_unlock(&pin_lock);
}

void pin_insert(struct fs_pin *pin, struct vfsmount *m)
{
	pin_insert_group(pin, m, &m->mnt_sb->s_pins);
}

void pin_kill(struct fs_pin *p)
{
	wait_queue_entry_t wait;

	if (!p) {
		rcu_read_unlock();
		return;
	}
	init_wait(&wait);
	spin_lock_irq(&p->wait.lock);
	if (likely(!p->done)) {
		p->done = -1;
		spin_unlock_irq(&p->wait.lock);
		rcu_read_unlock();
		p->kill(p);
		return;
	}
	if (p->done > 0) {
		spin_unlock_irq(&p->wait.lock);
		rcu_read_unlock();
		return;
	}
	__add_wait_queue(&p->wait, &wait);
	while (1) {
		set_current_state(TASK_UNINTERRUPTIBLE);
		spin_unlock_irq(&p->wait.lock);
		rcu_read_unlock();
		schedule();
		rcu_read_lock();
		if (likely(list_empty(&wait.entry)))
			break;
		/* OK, we know p couldn't have been freed yet */
		spin_lock_irq(&p->wait.lock);
		if (p->done > 0) {
			spin_unlock_irq(&p->wait.lock);
			break;
		}
	}
	rcu_read_unlock();
}

void mnt_pin_kill(struct mount *m)
{
	while (1) {
		struct hlist_node *p;
		rcu_read_lock();
		p = ACCESS_ONCE(m->mnt_pins.first);
		if (!p) {
			rcu_read_unlock();
			break;
		}
		pin_kill(hlist_entry(p, struct fs_pin, m_list));
	}
}

void group_pin_kill(struct hlist_head *p)
{
	while (1) {
		struct hlist_node *q;
		rcu_read_lock();
		q = ACCESS_ONCE(p->first);
		if (!q) {
			rcu_read_unlock();
			break;
		}
		pin_kill(hlist_entry(q, struct fs_pin, s_list));
	}
}
Commit	Line	Data
efb170c2	1	#include <linux/fs.h>
59eda0e0	2	#include <linux/sched.h>
efb170c2	3	#include <linux/slab.h>
8fa1f1c2	4	#include "internal.h"
efb170c2 AV	5	#include "mount.h"
efb170c2 AV	6
efb170c2 AV	7	static DEFINE_SPINLOCK(pin_lock);
efb170c2 AV	8
efb170c2 AV	9	void pin_remove(struct fs_pin *pin)
	10	{
	11	spin_lock(&pin_lock);
820f9f14 EB	12	hlist_del_init(&pin->m_list);
820f9f14 EB	13	hlist_del_init(&pin->s_list);
efb170c2	14	spin_unlock(&pin_lock);
59eda0e0 AV	15	spin_lock_irq(&pin->wait.lock);
	16	pin->done = 1;
	17	wake_up_locked(&pin->wait);
	18	spin_unlock_irq(&pin->wait.lock);
efb170c2 AV	19	}
efb170c2 AV	20
fdab684d	21	void pin_insert_group(struct fs_pin pin, struct vfsmount m, struct hlist_head *p)
efb170c2 AV	22	{
efb170c2 AV	23	spin_lock(&pin_lock);
fdab684d AV	24	if (p)
fdab684d AV	25	hlist_add_head(&pin->s_list, p);
efb170c2 AV	26	hlist_add_head(&pin->m_list, &real_mount(m)->mnt_pins);
	27	spin_unlock(&pin_lock);
	28	}
	29
fdab684d AV	30	void pin_insert(struct fs_pin pin, struct vfsmount m)
	31	{
	32	pin_insert_group(pin, m, &m->mnt_sb->s_pins);
	33	}
	34
59eda0e0 AV	35	void pin_kill(struct fs_pin *p)
59eda0e0 AV	36	{
ac6424b9	37	wait_queue_entry_t wait;
59eda0e0 AV	38
	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();
2055da97	64	if (likely(list_empty(&wait.entry)))
59eda0e0 AV	65	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
8fa1f1c2	76	void mnt_pin_kill(struct mount *m)
efb170c2 AV	77	{
	78	while (1) {
	79	struct hlist_node *p;
efb170c2	80	rcu_read_lock();
8fa1f1c2	81	p = ACCESS_ONCE(m->mnt_pins.first);
efb170c2 AV	82	if (!p) {
	83	rcu_read_unlock();
	84	break;
	85	}
59eda0e0	86	pin_kill(hlist_entry(p, struct fs_pin, m_list));
efb170c2 AV	87	}
	88	}
	89
fdab684d	90	void group_pin_kill(struct hlist_head *p)
efb170c2 AV	91	{
efb170c2 AV	92	while (1) {
fdab684d	93	struct hlist_node *q;
efb170c2	94	rcu_read_lock();
fdab684d AV	95	q = ACCESS_ONCE(p->first);
fdab684d AV	96	if (!q) {
efb170c2 AV	97	rcu_read_unlock();
	98	break;
	99	}
59eda0e0	100	pin_kill(hlist_entry(q, struct fs_pin, s_list));
efb170c2 AV	101	}
efb170c2 AV	102	}