#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_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.task_list))) 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)); } }