make acct_kill() wait for file closing.

Do actual closing of file via schedule_work().  And use
__fput_sync() there.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

1 files changed, 17 insertions, 3 deletions

diff --git a/kernel/acct.c b/kernel/acct.c
index 6fd375f15626..d9ebc96b1126 100644
--- a/kernel/acct.c
+++ b/kernel/acct.c
@@ -92,6 +92,8 @@ struct bsd_acct_struct {
         unsigned long           needcheck;
         struct file             *file;
         struct pid_namespace    *ns;
+        struct work_struct      work;
+        struct completion       done;
 };
 
 static void acct_free_rcu(struct rcu_head *head)
@@ -176,15 +178,27 @@ again:
         return res;
 }
 
+static void close_work(struct work_struct *work)
+{
+        struct bsd_acct_struct *acct = container_of(work, struct bsd_acct_struct, work);
+        struct file *file = acct->file;
+        mnt_unpin(file->f_path.mnt);
+        if (file->f_op->flush)
+                file->f_op->flush(file, NULL);
+        __fput_sync(file);
+        complete(&acct->done);
+}
+
 static void acct_kill(struct bsd_acct_struct *acct,
                       struct bsd_acct_struct *new)
 {
         if (acct) {
-                struct file *file = acct->file;
                 struct pid_namespace *ns = acct->ns;
                 do_acct_process(acct);
-                mnt_unpin(file->f_path.mnt);
-                filp_close(file, NULL);
+                INIT_WORK(&acct->work, close_work);
+                init_completion(&acct->done);
+                schedule_work(&acct->work);
+                wait_for_completion(&acct->done);
                 spin_lock(&acct_lock);
                 hlist_del(&acct->m_list);
                 hlist_del(&acct->s_list);