1 files changed, 144 insertions, 78 deletions

diff --git a/kernel/acct.c b/kernel/acct.c
index 91e1cfd734d2..dd68b9059418 100644
--- a/kernel/acct.c
+++ b/kernel/acct.c
@@ -75,37 +75,39 @@ int acct_parm[3] = {4, 2, 30};
 /*
  * External references and all of the globals.
  */
-static void do_acct_process(struct pid_namespace *ns, struct file *);
+static void do_acct_process(struct bsd_acct_struct *acct,
+                struct pid_namespace *ns, struct file *);
 
 /*
  * This structure is used so that all the data protected by lock
  * can be placed in the same cache line as the lock.  This primes
  * the cache line to have the data after getting the lock.
  */
-struct acct_glbs {
-        spinlock_t              lock;
+struct bsd_acct_struct {
         volatile int            active;
         volatile int            needcheck;
         struct file             *file;
         struct pid_namespace    *ns;
         struct timer_list       timer;
+        struct list_head        list;
 };
 
-static struct acct_glbs acct_globals __cacheline_aligned =
-        {__SPIN_LOCK_UNLOCKED(acct_globals.lock)};
+static DEFINE_SPINLOCK(acct_lock);
+static LIST_HEAD(acct_list);
 
 /*
  * Called whenever the timer says to check the free space.
  */
-static void acct_timeout(unsigned long unused)
+static void acct_timeout(unsigned long x)
 {
-        acct_globals.needcheck = 1;
+        struct bsd_acct_struct *acct = (struct bsd_acct_struct *)x;
+        acct->needcheck = 1;
 }
 
 /*
  * Check the amount of free space and suspend/resume accordingly.
  */
-static int check_free_space(struct file *file)
+static int check_free_space(struct bsd_acct_struct *acct, struct file *file)
 {
         struct kstatfs sbuf;
         int res;
@@ -113,11 +115,11 @@ static int check_free_space(struct file *file)
         sector_t resume;
         sector_t suspend;
 
-        spin_lock(&acct_globals.lock);
-        res = acct_globals.active;
-        if (!file || !acct_globals.needcheck)
+        spin_lock(&acct_lock);
+        res = acct->active;
+        if (!file || !acct->needcheck)
                 goto out;
-        spin_unlock(&acct_globals.lock);
+        spin_unlock(&acct_lock);
 
         /* May block */
         if (vfs_statfs(file->f_path.dentry, &sbuf))
@@ -136,35 +138,35 @@ static int check_free_space(struct file *file)
                 act = 0;
 
         /*
-         * If some joker switched acct_globals.file under us we'ld better be
+         * If some joker switched acct->file under us we'ld better be
          * silent and _not_ touch anything.
          */
-        spin_lock(&acct_globals.lock);
-        if (file != acct_globals.file) {
+        spin_lock(&acct_lock);
+        if (file != acct->file) {
                 if (act)
                         res = act>0;
                 goto out;
         }
 
-        if (acct_globals.active) {
+        if (acct->active) {
                 if (act < 0) {
-                        acct_globals.active = 0;
+                        acct->active = 0;
                         printk(KERN_INFO "Process accounting paused\n");
                 }
         } else {
                 if (act > 0) {
-                        acct_globals.active = 1;
+                        acct->active = 1;
                         printk(KERN_INFO "Process accounting resumed\n");
                 }
         }
 
-        del_timer(&acct_globals.timer);
-        acct_globals.needcheck = 0;
-        acct_globals.timer.expires = jiffies + ACCT_TIMEOUT*HZ;
-        add_timer(&acct_globals.timer);
-        res = acct_globals.active;
+        del_timer(&acct->timer);
+        acct->needcheck = 0;
+        acct->timer.expires = jiffies + ACCT_TIMEOUT*HZ;
+        add_timer(&acct->timer);
+        res = acct->active;
 out:
-        spin_unlock(&acct_globals.lock);
+        spin_unlock(&acct_lock);
         return res;
 }
 
@@ -172,39 +174,41 @@ out:
  * Close the old accounting file (if currently open) and then replace
  * it with file (if non-NULL).
  *
- * NOTE: acct_globals.lock MUST be held on entry and exit.
+ * NOTE: acct_lock MUST be held on entry and exit.
  */
-static void acct_file_reopen(struct file *file)
+static void acct_file_reopen(struct bsd_acct_struct *acct, struct file *file,
+                struct pid_namespace *ns)
 {
         struct file *old_acct = NULL;
         struct pid_namespace *old_ns = NULL;
 
-        if (acct_globals.file) {
-                old_acct = acct_globals.file;
-                old_ns = acct_globals.ns;
-                del_timer(&acct_globals.timer);
-                acct_globals.active = 0;
-                acct_globals.needcheck = 0;
-                acct_globals.file = NULL;
+        if (acct->file) {
+                old_acct = acct->file;
+                old_ns = acct->ns;
+                del_timer(&acct->timer);
+                acct->active = 0;
+                acct->needcheck = 0;
+                acct->file = NULL;
+                acct->ns = NULL;
+                list_del(&acct->list);
         }
         if (file) {
-                acct_globals.file = file;
-                acct_globals.ns = get_pid_ns(task_active_pid_ns(current));
-                acct_globals.needcheck = 0;
-                acct_globals.active = 1;
+                acct->file = file;
+                acct->ns = ns;
+                acct->needcheck = 0;
+                acct->active = 1;
+                list_add(&acct->list, &acct_list);
                 /* It's been deleted if it was used before so this is safe */
-                init_timer(&acct_globals.timer);
-                acct_globals.timer.function = acct_timeout;
-                acct_globals.timer.expires = jiffies + ACCT_TIMEOUT*HZ;
-                add_timer(&acct_globals.timer);
+                setup_timer(&acct->timer, acct_timeout, (unsigned long)acct);
+                acct->timer.expires = jiffies + ACCT_TIMEOUT*HZ;
+                add_timer(&acct->timer);
         }
         if (old_acct) {
                 mnt_unpin(old_acct->f_path.mnt);
-                spin_unlock(&acct_globals.lock);
-                do_acct_process(old_ns, old_acct);
+                spin_unlock(&acct_lock);
+                do_acct_process(acct, old_ns, old_acct);
                 filp_close(old_acct, NULL);
-                put_pid_ns(old_ns);
-                spin_lock(&acct_globals.lock);
+                spin_lock(&acct_lock);
         }
 }
 
@@ -212,6 +216,8 @@ static int acct_on(char *name)
 {
         struct file *file;
         int error;
+        struct pid_namespace *ns;
+        struct bsd_acct_struct *acct = NULL;
 
         /* Difference from BSD - they don't do O_APPEND */
         file = filp_open(name, O_WRONLY|O_APPEND|O_LARGEFILE, 0);
@@ -228,18 +234,34 @@ static int acct_on(char *name)
                 return -EIO;
         }
 
+        ns = task_active_pid_ns(current);
+        if (ns->bacct == NULL) {
+                acct = kzalloc(sizeof(struct bsd_acct_struct), GFP_KERNEL);
+                if (acct == NULL) {
+                        filp_close(file, NULL);
+                        return -ENOMEM;
+                }
+        }
+
         error = security_acct(file);
         if (error) {
+                kfree(acct);
                 filp_close(file, NULL);
                 return error;
         }
 
-        spin_lock(&acct_globals.lock);
+        spin_lock(&acct_lock);
+        if (ns->bacct == NULL) {
+                ns->bacct = acct;
+                acct = NULL;
+        }
+
         mnt_pin(file->f_path.mnt);
-        acct_file_reopen(file);
-        spin_unlock(&acct_globals.lock);
+        acct_file_reopen(ns->bacct, file, ns);
+        spin_unlock(&acct_lock);
 
         mntput(file->f_path.mnt); /* it's pinned, now give up active reference */
+        kfree(acct);
 
         return 0;
 }
@@ -269,11 +291,17 @@ asmlinkage long sys_acct(const char __user *name)
                 error = acct_on(tmp);
                 putname(tmp);
         } else {
+                struct bsd_acct_struct *acct;
+
+                acct = task_active_pid_ns(current)->bacct;
+                if (acct == NULL)
+                        return 0;
+
                 error = security_acct(NULL);
                 if (!error) {
-                        spin_lock(&acct_globals.lock);
-                        acct_file_reopen(NULL);
-                        spin_unlock(&acct_globals.lock);
+                        spin_lock(&acct_lock);
+                        acct_file_reopen(acct, NULL, NULL);
+                        spin_unlock(&acct_lock);
                 }
         }
         return error;
@@ -288,10 +316,16 @@ asmlinkage long sys_acct(const char __user *name)
  */
 void acct_auto_close_mnt(struct vfsmount *m)
 {
-        spin_lock(&acct_globals.lock);
-        if (acct_globals.file && acct_globals.file->f_path.mnt == m)
-                acct_file_reopen(NULL);
-        spin_unlock(&acct_globals.lock);
+        struct bsd_acct_struct *acct;
+
+        spin_lock(&acct_lock);
+restart:
+        list_for_each_entry(acct, &acct_list, list)
+                if (acct->file && acct->file->f_path.mnt == m) {
+                        acct_file_reopen(acct, NULL, NULL);
+                        goto restart;
+                }
+        spin_unlock(&acct_lock);
 }
 
 /**
@@ -303,12 +337,31 @@ void acct_auto_close_mnt(struct vfsmount *m)
  */
 void acct_auto_close(struct super_block *sb)
 {
-        spin_lock(&acct_globals.lock);
-        if (acct_globals.file &&
-            acct_globals.file->f_path.mnt->mnt_sb == sb) {
-                acct_file_reopen(NULL);
+        struct bsd_acct_struct *acct;
+
+        spin_lock(&acct_lock);
+restart:
+        list_for_each_entry(acct, &acct_list, list)
+                if (acct->file && acct->file->f_path.mnt->mnt_sb == sb) {
+                        acct_file_reopen(acct, NULL, NULL);
+                        goto restart;
+                }
+        spin_unlock(&acct_lock);
+}
+
+void acct_exit_ns(struct pid_namespace *ns)
+{
+        struct bsd_acct_struct *acct;
+
+        spin_lock(&acct_lock);
+        acct = ns->bacct;
+        if (acct != NULL) {
+                if (acct->file != NULL)
+                        acct_file_reopen(acct, NULL, NULL);
+
+                kfree(acct);
         }
-        spin_unlock(&acct_globals.lock);
+        spin_unlock(&acct_lock);
 }
 
 /*
@@ -425,7 +478,8 @@ static u32 encode_float(u64 value)
 /*
  *  do_acct_process does all actual work. Caller holds the reference to file.
  */
-static void do_acct_process(struct pid_namespace *ns, struct file *file)
+static void do_acct_process(struct bsd_acct_struct *acct,
+                struct pid_namespace *ns, struct file *file)
 {
         struct pacct_struct *pacct = &current->signal->pacct;
         acct_t ac;
@@ -440,7 +494,7 @@ static void do_acct_process(struct pid_namespace *ns, struct file *file)
          * First check to see if there is enough free_space to continue
          * the process accounting system.
          */
-        if (!check_free_space(file))
+        if (!check_free_space(acct, file))
                 return;
 
         /*
@@ -577,34 +631,46 @@ void acct_collect(long exitcode, int group_dead)
         spin_unlock_irq(&current->sighand->siglock);
 }
 
-/**
- * acct_process - now just a wrapper around do_acct_process
- * @exitcode: task exit code
- *
- * handles process accounting for an exiting task
- */
-void acct_process(void)
+static void acct_process_in_ns(struct pid_namespace *ns)
 {
         struct file *file = NULL;
-        struct pid_namespace *ns;
+        struct bsd_acct_struct *acct;
 
+        acct = ns->bacct;
         /*
          * accelerate the common fastpath:
          */
-        if (!acct_globals.file)
+        if (!acct || !acct->file)
                 return;
 
-        spin_lock(&acct_globals.lock);
-        file = acct_globals.file;
+        spin_lock(&acct_lock);
+        file = acct->file;
         if (unlikely(!file)) {
-                spin_unlock(&acct_globals.lock);
+                spin_unlock(&acct_lock);
                 return;
         }
         get_file(file);
-        ns = get_pid_ns(acct_globals.ns);
-        spin_unlock(&acct_globals.lock);
+        spin_unlock(&acct_lock);
 
-        do_acct_process(ns, file);
+        do_acct_process(acct, ns, file);
         fput(file);
-        put_pid_ns(ns);
+}
+
+/**
+ * acct_process - now just a wrapper around acct_process_in_ns,
+ * which in turn is a wrapper around do_acct_process.
+ *
+ * handles process accounting for an exiting task
+ */
+void acct_process(void)
+{
+        struct pid_namespace *ns;
+
+        /*
+         * This loop is safe lockless, since current is still
+         * alive and holds its namespace, which in turn holds
+         * its parent.
+         */
+        for (ns = task_active_pid_ns(current); ns != NULL; ns = ns->parent)
+                acct_process_in_ns(ns);
 }