diff options
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/acct.c | 127 |
1 files changed, 32 insertions, 95 deletions
diff --git a/kernel/acct.c b/kernel/acct.c index afeaaa6f49bf..a7993a6cb604 100644 --- a/kernel/acct.c +++ b/kernel/acct.c @@ -59,7 +59,7 @@ #include <asm/div64.h> #include <linux/blkdev.h> /* sector_div */ #include <linux/pid_namespace.h> -#include <../fs/mount.h> /* will go away when we refactor */ +#include <linux/fs_pin.h> /* * These constants control the amount of freespace that suspend and @@ -78,17 +78,6 @@ int acct_parm[3] = {4, 2, 30}; */ static void do_acct_process(struct bsd_acct_struct *acct); -struct fs_pin { - atomic_long_t count; - union { - struct { - struct hlist_node s_list; - struct hlist_node m_list; - }; - struct rcu_head rcu; - }; -}; - struct bsd_acct_struct { struct fs_pin pin; struct mutex lock; @@ -100,13 +89,6 @@ struct bsd_acct_struct { struct completion done; }; -static void pin_free_rcu(struct rcu_head *head) -{ - kfree(container_of(head, struct fs_pin, rcu)); -} - -static DEFINE_SPINLOCK(acct_lock); - /* * Check the amount of free space and suspend/resume accordingly. */ @@ -142,29 +124,6 @@ out: return acct->active; } -static void pin_put(struct fs_pin *p) -{ - if (atomic_long_dec_and_test(&p->count)) - call_rcu(&p->rcu, pin_free_rcu); -} - -static struct bsd_acct_struct *__acct_get(struct bsd_acct_struct *res) -{ - if (!atomic_long_inc_not_zero(&res->pin.count)) { - rcu_read_unlock(); - cpu_relax(); - return NULL; - } - rcu_read_unlock(); - mutex_lock(&res->lock); - if (!res->ns) { - mutex_unlock(&res->lock); - pin_put(&res->pin); - return NULL; - } - return res; -} - static struct bsd_acct_struct *acct_get(struct pid_namespace *ns) { struct bsd_acct_struct *res; @@ -176,9 +135,18 @@ again: rcu_read_unlock(); return NULL; } - res = __acct_get(res); - if (!res) + if (!atomic_long_inc_not_zero(&res->pin.count)) { + rcu_read_unlock(); + cpu_relax(); goto again; + } + rcu_read_unlock(); + mutex_lock(&res->lock); + if (!res->ns) { + mutex_unlock(&res->lock); + pin_put(&res->pin); + goto again; + } return res; } @@ -203,19 +171,8 @@ static void acct_kill(struct bsd_acct_struct *acct, init_completion(&acct->done); schedule_work(&acct->work); wait_for_completion(&acct->done); - spin_lock(&acct_lock); - hlist_del(&acct->pin.m_list); - hlist_del(&acct->pin.s_list); - spin_unlock(&acct_lock); + pin_remove(&acct->pin); ns->bacct = new; - if (new) { - struct vfsmount *m = new->file->f_path.mnt; - spin_lock(&acct_lock); - hlist_add_head(&new->pin.s_list, &m->mnt_sb->s_pins); - hlist_add_head(&new->pin.m_list, &real_mount(m)->mnt_pins); - spin_unlock(&acct_lock); - mutex_unlock(&new->lock); - } acct->ns = NULL; atomic_long_dec(&acct->pin.count); mutex_unlock(&acct->lock); @@ -223,6 +180,19 @@ static void acct_kill(struct bsd_acct_struct *acct, } } +static void acct_pin_kill(struct fs_pin *pin) +{ + struct bsd_acct_struct *acct; + acct = container_of(pin, struct bsd_acct_struct, pin); + mutex_lock(&acct->lock); + if (!acct->ns) { + mutex_unlock(&acct->lock); + pin_put(pin); + acct = NULL; + } + acct_kill(acct, NULL); +} + static int acct_on(struct filename *pathname) { struct file *file; @@ -254,25 +224,22 @@ static int acct_on(struct filename *pathname) } atomic_long_set(&acct->pin.count, 1); + acct->pin.kill = acct_pin_kill; acct->file = file; acct->needcheck = jiffies; acct->ns = ns; mutex_init(&acct->lock); mnt = file->f_path.mnt; mnt_pin(mnt); + mutex_lock_nested(&acct->lock, 1); /* nobody has seen it yet */ + pin_insert(&acct->pin, mnt); old = acct_get(ns); - mutex_lock_nested(&acct->lock, 1); /* nobody has seen it yet */ - if (old) { + if (old) acct_kill(old, acct); - } else { + else ns->bacct = acct; - spin_lock(&acct_lock); - hlist_add_head(&acct->pin.s_list, &mnt->mnt_sb->s_pins); - hlist_add_head(&acct->pin.m_list, &real_mount(mnt)->mnt_pins); - spin_unlock(&acct_lock); - mutex_unlock(&acct->lock); - } + mutex_unlock(&acct->lock); mntput(mnt); /* it's pinned, now give up active reference */ return 0; } @@ -312,36 +279,6 @@ SYSCALL_DEFINE1(acct, const char __user *, name) return error; } -void acct_auto_close_mnt(struct hlist_head *list) -{ - rcu_read_lock(); - while (1) { - struct hlist_node *p = ACCESS_ONCE(list->first); - if (!p) - break; - acct_kill(__acct_get(hlist_entry(p, - struct bsd_acct_struct, - pin.m_list)), NULL); - rcu_read_lock(); - } - rcu_read_unlock(); -} - -void acct_auto_close(struct hlist_head *list) -{ - rcu_read_lock(); - while (1) { - struct hlist_node *p = ACCESS_ONCE(list->first); - if (!p) - break; - acct_kill(__acct_get(hlist_entry(p, - struct bsd_acct_struct, - pin.s_list)), NULL); - rcu_read_lock(); - } - rcu_read_unlock(); -} - void acct_exit_ns(struct pid_namespace *ns) { acct_kill(acct_get(ns), NULL); |