shrink_dentry_tree(): unify the calls of shrink_dentry_list()

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

diff --git a/fs/dcache.c b/fs/dcache.c
index beb0523c33047b094d79449e6459aec875a2ac07..1f4435b7f9cea8c5f014634bfcfd3669ed10995f 100644 (file)
--- a/fs/dcache.c
+++ b/fs/dcache.c
@@ -630,12 +630,14 @@ struct completion_list {
  *  Use ->waiters for a single-linked list of struct completion_list of
  *  waiters.
  */
-static inline void d_add_waiter(struct dentry *dentry, struct completion_list *p)
+static inline bool d_add_waiter(struct dentry *dentry, struct completion_list *p)
 {
-       struct completion_list *v = dentry->waiters;
+       if (unlikely(dentry->d_flags & DCACHE_DENTRY_KILLED))
+               return false;
        init_completion(&p->completion);
-       p->next = v;
+       p->next = dentry->waiters;
        dentry->waiters = p;
+       return true;
 }
 
 static inline void d_complete_waiters(struct dentry *dentry)
@@ -1705,7 +1707,9 @@ out:
 static void shrink_dcache_tree(struct dentry *parent, bool for_umount)
 {
        for (;;) {
-               struct select_data data = {.start = parent};
+               struct completion_list wait;
+               bool need_wait = false;
+               struct select_data data = { .start = parent };
 
                INIT_LIST_HEAD(&data.dispose);
                d_walk(parent, &data,
@@ -1737,22 +1741,18 @@ static void shrink_dcache_tree(struct dentry *parent, bool for_umount)
                        spin_lock(&v->d_lock);
                        rcu_read_unlock();
 
-                       if (v->d_lockref.count < 0 &&
-                           !(v->d_flags & DCACHE_DENTRY_KILLED)) {
-                               struct completion_list wait;
-                               // It's busy dying; have it notify us once
-                               // it becomes invisible to d_walk().
-                               d_add_waiter(v, &wait);
+                       if (unlikely(v->d_lockref.count < 0)) {
+                               // It's doomed; if it isn't dead yet, notify us
+                               // once it becomes invisible to d_walk().
+                               need_wait = d_add_waiter(v, &wait);
                                spin_unlock(&v->d_lock);
-                               if (!list_empty(&data.dispose))
-                                       shrink_dentry_list(&data.dispose);
-                               wait_for_completion(&wait.completion);
-                               continue;
+                       } else {
+                               shrink_kill(v);
                        }
-                       shrink_kill(v);
                }
-               if (!list_empty(&data.dispose))
-                       shrink_dentry_list(&data.dispose);
+               shrink_dentry_list(&data.dispose);
+               if (unlikely(need_wait))
+                       wait_for_completion(&wait.completion);
        }
 }