79 lines
1.5 KiB
C
79 lines
1.5 KiB
C
#include <linux/fs.h>
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#include <linux/slab.h>
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#include <linux/fs_pin.h>
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#include "internal.h"
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#include "mount.h"
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static void pin_free_rcu(struct rcu_head *head)
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{
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kfree(container_of(head, struct fs_pin, rcu));
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}
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static DEFINE_SPINLOCK(pin_lock);
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void pin_put(struct fs_pin *p)
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{
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if (atomic_long_dec_and_test(&p->count))
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call_rcu(&p->rcu, pin_free_rcu);
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}
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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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}
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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 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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struct fs_pin *pin;
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rcu_read_lock();
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p = ACCESS_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 = hlist_entry(p, struct fs_pin, m_list);
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if (!atomic_long_inc_not_zero(&pin->count)) {
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rcu_read_unlock();
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cpu_relax();
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continue;
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}
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rcu_read_unlock();
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pin->kill(pin);
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}
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}
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void sb_pin_kill(struct super_block *sb)
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{
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while (1) {
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struct hlist_node *p;
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struct fs_pin *pin;
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rcu_read_lock();
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p = ACCESS_ONCE(sb->s_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 = hlist_entry(p, struct fs_pin, s_list);
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if (!atomic_long_inc_not_zero(&pin->count)) {
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rcu_read_unlock();
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cpu_relax();
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continue;
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}
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rcu_read_unlock();
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pin->kill(pin);
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}
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}
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