* lock ordering than usbfs:
*/
lockdep_set_class(&s->s_lock, &type->s_lock_key);
- down_write(&s->s_umount);
+ /*
+ * sget() can have s_umount recursion.
+ *
+ * When it cannot find a suitable sb, it allocates a new
+ * one (this one), and tries again to find a suitable old
+ * one.
+ *
+ * In case that succeeds, it will acquire the s_umount
+ * lock of the old one. Since these are clearly distrinct
+ * locks, and this object isn't exposed yet, there's no
+ * risk of deadlocks.
+ *
+ * Annotate this by putting this lock in a different
+ * subclass.
+ */
+ down_write_nested(&s->s_umount, SINGLE_DEPTH_NESTING);
s->s_count = S_BIAS;
atomic_set(&s->s_active, 1);
mutex_init(&s->s_vfs_rename_mutex);
continue;
if (!grab_super(old))
goto retry;
- if (s)
+ if (s) {
+ up_write(&s->s_umount);
destroy_super(s);
+ }
return old;
}
}
err = set(s, data);
if (err) {
spin_unlock(&sb_lock);
+ up_write(&s->s_umount);
destroy_super(s);
return ERR_PTR(err);
}