From 57f0f512b273f60d52568b8c6b77e17f5636edc0 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Andr=C3=A9=20Fabian=20Silva=20Delgado?= Date: Wed, 5 Aug 2015 17:04:01 -0300 Subject: Initial import --- fs/fs_pin.c | 102 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 102 insertions(+) create mode 100644 fs/fs_pin.c (limited to 'fs/fs_pin.c') diff --git a/fs/fs_pin.c b/fs/fs_pin.c new file mode 100644 index 000000000..611b5408f --- /dev/null +++ b/fs/fs_pin.c @@ -0,0 +1,102 @@ +#include +#include +#include +#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)); + } +} -- cgit v1.2.3