diff options
| -rw-r--r-- | fs/Makefile | 2 | ||||
| -rw-r--r-- | fs/fs_pin.c | 77 | ||||
| -rw-r--r-- | include/linux/acct.h | 6 | ||||
| -rw-r--r-- | include/linux/fs_pin.h | 17 | ||||
| -rw-r--r-- | kernel/acct.c | 127 |
5 files changed, 129 insertions, 100 deletions
diff --git a/fs/Makefile b/fs/Makefile index 4030cbf..90c8852 100644 --- a/fs/Makefile +++ b/fs/Makefile @@ -11,7 +11,7 @@ obj-y := open.o read_write.o file_table.o super.o \ attr.o bad_inode.o file.o filesystems.o namespace.o \ seq_file.o xattr.o libfs.o fs-writeback.o \ pnode.o splice.o sync.o utimes.o \ - stack.o fs_struct.o statfs.o + stack.o fs_struct.o statfs.o fs_pin.o ifeq ($(CONFIG_BLOCK),y) obj-y += buffer.o block_dev.o direct-io.o mpage.o diff --git a/fs/fs_pin.c b/fs/fs_pin.c new file mode 100644 index 0000000..f3ce0b8 --- /dev/null +++ b/fs/fs_pin.c @@ -0,0 +1,77 @@ +#include <linux/fs.h> +#include <linux/slab.h> +#include <linux/fs_pin.h> +#include "mount.h" + +static void pin_free_rcu(struct rcu_head *head) +{ + kfree(container_of(head, struct fs_pin, rcu)); +} + +static DEFINE_SPINLOCK(pin_lock); + +void pin_put(struct fs_pin *p) +{ + if (atomic_long_dec_and_test(&p->count)) + call_rcu(&p->rcu, pin_free_rcu); +} + +void pin_remove(struct fs_pin *pin) +{ + spin_lock(&pin_lock); + hlist_del(&pin->m_list); + hlist_del(&pin->s_list); + spin_unlock(&pin_lock); +} + +void pin_insert(struct fs_pin *pin, struct vfsmount *m) +{ + spin_lock(&pin_lock); + hlist_add_head(&pin->s_list, &m->mnt_sb->s_pins); + hlist_add_head(&pin->m_list, &real_mount(m)->mnt_pins); + spin_unlock(&pin_lock); +} + +void acct_auto_close_mnt(struct hlist_head *list) +{ + while (1) { + struct hlist_node *p; + struct fs_pin *pin; + rcu_read_lock(); + p = ACCESS_ONCE(list->first); + if (!p) { + rcu_read_unlock(); + break; + } + pin = hlist_entry(p, struct fs_pin, m_list); + if (!atomic_long_inc_not_zero(&pin->count)) { + rcu_read_unlock(); + cpu_relax(); + continue; + } + rcu_read_unlock(); + pin->kill(pin); + } +} + +void acct_auto_close(struct hlist_head *list) +{ + while (1) { + struct hlist_node *p; + struct fs_pin *pin; + rcu_read_lock(); + p = ACCESS_ONCE(list->first); + if (!p) { + rcu_read_unlock(); + break; + } + pin = hlist_entry(p, struct fs_pin, s_list); + if (!atomic_long_inc_not_zero(&pin->count)) { + rcu_read_unlock(); + cpu_relax(); + continue; + } + rcu_read_unlock(); + pin->kill(pin); + } +} diff --git a/include/linux/acct.h b/include/linux/acct.h index 65a4f88..1378379 100644 --- a/include/linux/acct.h +++ b/include/linux/acct.h @@ -24,18 +24,16 @@ struct super_block; struct pacct_struct; struct pid_namespace; extern int acct_parm[]; /* for sysctl */ -extern void acct_auto_close(struct hlist_head *); -extern void acct_auto_close_mnt(struct hlist_head *); extern void acct_collect(long exitcode, int group_dead); extern void acct_process(void); extern void acct_exit_ns(struct pid_namespace *); #else -#define acct_auto_close(x) do { } while (0) -#define acct_auto_close_mnt(x) do { } while (0) #define acct_collect(x,y) do { } while (0) #define acct_process() do { } while (0) #define acct_exit_ns(ns) do { } while (0) #endif +extern void acct_auto_close(struct hlist_head *); +extern void acct_auto_close_mnt(struct hlist_head *); /* * ACCT_VERSION numbers as yet defined: diff --git a/include/linux/fs_pin.h b/include/linux/fs_pin.h new file mode 100644 index 0000000..f66525e --- /dev/null +++ b/include/linux/fs_pin.h @@ -0,0 +1,17 @@ +#include <linux/fs.h> + +struct fs_pin { + atomic_long_t count; + union { + struct { + struct hlist_node s_list; + struct hlist_node m_list; + }; + struct rcu_head rcu; + }; + void (*kill)(struct fs_pin *); +}; + +void pin_put(struct fs_pin *); +void pin_remove(struct fs_pin *); +void pin_insert(struct fs_pin *, struct vfsmount *); diff --git a/kernel/acct.c b/kernel/acct.c index afeaaa6..a7993a6 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); |
