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

// SPDX-License-Identifier: GPL-2.0
#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 = READ_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 = READ_ONCE(p->first);
		if (!q) {
			rcu_read_unlock();
			break;
		}
		pin_kill(hlist_entry(q, struct fs_pin, s_list));
	}
}
Commit	Line	Data
	1	// SPDX-License-Identifier: GPL-2.0
	2	#include <linux/fs.h>
	3	#include <linux/sched.h>
	4	#include <linux/slab.h>
	5	#include "internal.h"
	6	#include "mount.h"
	7
	8	static DEFINE_SPINLOCK(pin_lock);
	9
	10	void pin_remove(struct fs_pin *pin)
	11	{
	12	spin_lock(&pin_lock);
	13	hlist_del_init(&pin->m_list);
	14	hlist_del_init(&pin->s_list);
	15	spin_unlock(&pin_lock);
	16	spin_lock_irq(&pin->wait.lock);
	17	pin->done = 1;
	18	wake_up_locked(&pin->wait);
	19	spin_unlock_irq(&pin->wait.lock);
	20	}
	21
	22	void pin_insert_group(struct fs_pin pin, struct vfsmount m, struct hlist_head *p)
	23	{
	24	spin_lock(&pin_lock);
	25	if (p)
	26	hlist_add_head(&pin->s_list, p);
	27	hlist_add_head(&pin->m_list, &real_mount(m)->mnt_pins);
	28	spin_unlock(&pin_lock);
	29	}
	30
	31	void pin_insert(struct fs_pin pin, struct vfsmount m)
	32	{
	33	pin_insert_group(pin, m, &m->mnt_sb->s_pins);
	34	}
	35
	36	void pin_kill(struct fs_pin *p)
	37	{
	38	wait_queue_entry_t wait;
	39
	40	if (!p) {
	41	rcu_read_unlock();
	42	return;
	43	}
	44	init_wait(&wait);
	45	spin_lock_irq(&p->wait.lock);
	46	if (likely(!p->done)) {
	47	p->done = -1;
	48	spin_unlock_irq(&p->wait.lock);
	49	rcu_read_unlock();
	50	p->kill(p);
	51	return;
	52	}
	53	if (p->done > 0) {
	54	spin_unlock_irq(&p->wait.lock);
	55	rcu_read_unlock();
	56	return;
	57	}
	58	__add_wait_queue(&p->wait, &wait);
	59	while (1) {
	60	set_current_state(TASK_UNINTERRUPTIBLE);
	61	spin_unlock_irq(&p->wait.lock);
	62	rcu_read_unlock();
	63	schedule();
	64	rcu_read_lock();
	65	if (likely(list_empty(&wait.entry)))
	66	break;
	67	/* OK, we know p couldn't have been freed yet */
	68	spin_lock_irq(&p->wait.lock);
	69	if (p->done > 0) {
	70	spin_unlock_irq(&p->wait.lock);
	71	break;
	72	}
	73	}
	74	rcu_read_unlock();
	75	}
	76
	77	void mnt_pin_kill(struct mount *m)
	78	{
	79	while (1) {
	80	struct hlist_node *p;
	81	rcu_read_lock();
	82	p = READ_ONCE(m->mnt_pins.first);
	83	if (!p) {
	84	rcu_read_unlock();
	85	break;
	86	}
	87	pin_kill(hlist_entry(p, struct fs_pin, m_list));
	88	}
	89	}
	90
	91	void group_pin_kill(struct hlist_head *p)
	92	{
	93	while (1) {
	94	struct hlist_node *q;
	95	rcu_read_lock();
	96	q = READ_ONCE(p->first);
	97	if (!q) {
	98	rcu_read_unlock();
	99	break;
	100	}
	101	pin_kill(hlist_entry(q, struct fs_pin, s_list));
	102	}
	103	}