Commit 0200894d authored by Al Viro's avatar Al Viro
Browse files

new helper: destroy_unused_super() 



Used for disposal of super_block instances that had never been reachable
via any shared data structures.  No need for RCU delay in there, everything
can be called directly.

Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
parent 6aa211e8

fs/super.c

+19 −12
Original line number Diff line number Diff line
@@ -171,6 +171,21 @@ static void destroy_super(struct super_block *s) 
	call_rcu(&s->rcu, destroy_super_rcu);

}



/* 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);

	put_user_ns(s->s_user_ns);

	kfree(s->s_subtype);

	/* no delays needed */

	destroy_super_work(&s->destroy_work);

}



/**

 *	alloc_super	-	create new superblock

 *	@type:	filesystem type superblock should belong to
@@ -256,7 +271,7 @@ 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;

}
@@ -484,19 +499,12 @@ struct super_block *sget_userns(struct file_system_type *type, 
				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;

		}

	}
@@ -511,8 +519,7 @@ struct super_block *sget_userns(struct file_system_type *type, 
	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;