From 59eda0e07f43c950d31756213b607af673e551f0 Mon Sep 17 00:00:00 2001 From: Al Viro Date: Sat, 10 Jan 2015 17:53:21 -0500 Subject: new fs_pin killing logics Signed-off-by: Al Viro --- fs/fs_pin.c | 54 ++++++++++++++++++++++++++++++++++++++++++++++++------ 1 file changed, 48 insertions(+), 6 deletions(-) (limited to 'fs/fs_pin.c') diff --git a/fs/fs_pin.c b/fs/fs_pin.c index 50ef7d2ef03c..0c77bdc238b2 100644 --- a/fs/fs_pin.c +++ b/fs/fs_pin.c @@ -1,4 +1,5 @@ #include +#include #include #include #include "internal.h" @@ -12,6 +13,10 @@ void pin_remove(struct fs_pin *pin) hlist_del(&pin->m_list); hlist_del(&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) @@ -28,19 +33,58 @@ 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; - struct fs_pin *pin; rcu_read_lock(); p = ACCESS_ONCE(m->mnt_pins.first); if (!p) { rcu_read_unlock(); break; } - pin = hlist_entry(p, struct fs_pin, m_list); - pin->kill(pin); + pin_kill(hlist_entry(p, struct fs_pin, m_list)); } } @@ -48,14 +92,12 @@ void group_pin_kill(struct hlist_head *p) { while (1) { struct hlist_node *q; - struct fs_pin *pin; rcu_read_lock(); q = ACCESS_ONCE(p->first); if (!q) { rcu_read_unlock(); break; } - pin = hlist_entry(q, struct fs_pin, s_list); - pin->kill(pin); + pin_kill(hlist_entry(q, struct fs_pin, s_list)); } } -- cgit v1.2.3-70-g09d2