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>

diff --git a/kernel/acct.c b/kernel/acct.c
index 6fd375f..d9ebc96 100644 (file)
--- 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);