Merge branch 'work.whack-a-mole' of git://git.kernel.org/pub/scm/linux/kernel/git...

[sfrench/cifs-2.6.git] / fs / super.c

diff --git a/fs/super.c b/fs/super.c
index 994db21f59bf58d3f83d750f8524d1c35849706b..d4e33e8f1e6fee3172e0e07e9d358587eea34bc4 100644 (file)
--- a/fs/super.c
+++ b/fs/super.c
@@ -155,21 +155,19 @@ static void destroy_super_rcu(struct rcu_head *head)
        schedule_work(&s->destroy_work);
 }
 
-/**
- *     destroy_super   -       frees a superblock
- *     @s: superblock to free
- *
- *     Frees a superblock.
- */
-static void destroy_super(struct super_block *s)
+/* Free a superblock that has never been seen by anyone */
+static void destroy_unused_super(struct super_block *s)
 {
+       if (!s)
+               return;
+       up_write(&s->s_umount);
        list_lru_destroy(&s->s_dentry_lru);
        list_lru_destroy(&s->s_inode_lru);
        security_sb_free(s);
-       WARN_ON(!list_empty(&s->s_mounts));
        put_user_ns(s->s_user_ns);
        kfree(s->s_subtype);
-       call_rcu(&s->rcu, destroy_super_rcu);
+       /* no delays needed */
+       destroy_super_work(&s->destroy_work);
 }
 
 /**
@@ -257,7 +255,7 @@ static struct super_block *alloc_super(struct file_system_type *type, int flags,
        return s;
 
 fail:
-       destroy_super(s);
+       destroy_unused_super(s);
        return NULL;
 }
 
@@ -266,11 +264,17 @@ fail:
 /*
  * Drop a superblock's refcount.  The caller must hold sb_lock.
  */
-static void __put_super(struct super_block *sb)
+static void __put_super(struct super_block *s)
 {
-       if (!--sb->s_count) {
-               list_del_init(&sb->s_list);
-               destroy_super(sb);
+       if (!--s->s_count) {
+               list_del_init(&s->s_list);
+               WARN_ON(s->s_dentry_lru.node);
+               WARN_ON(s->s_inode_lru.node);
+               WARN_ON(!list_empty(&s->s_mounts));
+               security_sb_free(s);
+               put_user_ns(s->s_user_ns);
+               kfree(s->s_subtype);
+               call_rcu(&s->rcu, destroy_super_rcu);
        }
 }
 
@@ -485,19 +489,12 @@ retry:
                                continue;
                        if (user_ns != old->s_user_ns) {
                                spin_unlock(&sb_lock);
-                               if (s) {
-                                       up_write(&s->s_umount);
-                                       destroy_super(s);
-                               }
+                               destroy_unused_super(s);
                                return ERR_PTR(-EBUSY);
                        }
                        if (!grab_super(old))
                                goto retry;
-                       if (s) {
-                               up_write(&s->s_umount);
-                               destroy_super(s);
-                               s = NULL;
-                       }
+                       destroy_unused_super(s);
                        return old;
                }
        }
@@ -512,8 +509,7 @@ retry:
        err = set(s, data);
        if (err) {
                spin_unlock(&sb_lock);
-               up_write(&s->s_umount);
-               destroy_super(s);
+               destroy_unused_super(s);
                return ERR_PTR(err);
        }
        s->s_type = type;