56cbb429d9
We used to need rather convoluted ordering trickery to guarantee that dput() of ex-mountpoints happens before the final mntput() of the same. Since we don't need that anymore, there's no point playing with fs_pin for that. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
98 lines
1.9 KiB
C
98 lines
1.9 KiB
C
// SPDX-License-Identifier: GPL-2.0
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#include <linux/fs.h>
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#include <linux/sched.h>
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#include <linux/slab.h>
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#include "internal.h"
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#include "mount.h"
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static DEFINE_SPINLOCK(pin_lock);
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void pin_remove(struct fs_pin *pin)
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{
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spin_lock(&pin_lock);
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hlist_del_init(&pin->m_list);
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hlist_del_init(&pin->s_list);
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spin_unlock(&pin_lock);
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spin_lock_irq(&pin->wait.lock);
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pin->done = 1;
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wake_up_locked(&pin->wait);
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spin_unlock_irq(&pin->wait.lock);
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}
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void pin_insert(struct fs_pin *pin, struct vfsmount *m)
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{
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spin_lock(&pin_lock);
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hlist_add_head(&pin->s_list, &m->mnt_sb->s_pins);
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hlist_add_head(&pin->m_list, &real_mount(m)->mnt_pins);
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spin_unlock(&pin_lock);
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}
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void pin_kill(struct fs_pin *p)
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{
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wait_queue_entry_t wait;
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if (!p) {
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rcu_read_unlock();
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return;
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}
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init_wait(&wait);
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spin_lock_irq(&p->wait.lock);
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if (likely(!p->done)) {
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p->done = -1;
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spin_unlock_irq(&p->wait.lock);
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rcu_read_unlock();
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p->kill(p);
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return;
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}
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if (p->done > 0) {
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spin_unlock_irq(&p->wait.lock);
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rcu_read_unlock();
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return;
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}
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__add_wait_queue(&p->wait, &wait);
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while (1) {
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set_current_state(TASK_UNINTERRUPTIBLE);
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spin_unlock_irq(&p->wait.lock);
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rcu_read_unlock();
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schedule();
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rcu_read_lock();
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if (likely(list_empty(&wait.entry)))
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break;
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/* OK, we know p couldn't have been freed yet */
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spin_lock_irq(&p->wait.lock);
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if (p->done > 0) {
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spin_unlock_irq(&p->wait.lock);
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break;
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}
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}
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rcu_read_unlock();
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}
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void mnt_pin_kill(struct mount *m)
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{
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while (1) {
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struct hlist_node *p;
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rcu_read_lock();
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p = READ_ONCE(m->mnt_pins.first);
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if (!p) {
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rcu_read_unlock();
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break;
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}
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pin_kill(hlist_entry(p, struct fs_pin, m_list));
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}
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}
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void group_pin_kill(struct hlist_head *p)
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{
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while (1) {
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struct hlist_node *q;
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rcu_read_lock();
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q = READ_ONCE(p->first);
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if (!q) {
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rcu_read_unlock();
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break;
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}
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pin_kill(hlist_entry(q, struct fs_pin, s_list));
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}
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}
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