Hongyi Jia <jiayisuse@xxxxxxxxx> wrote:
> +bool __fscache_check_consistency(struct fscache_cookie *cookie)
> +{
> + struct fscache_object *object;
> +
> + if (cookie->def->type != FSCACHE_COOKIE_TYPE_DATAFILE)
> + return false;
> +
> + if (hlist_empty(&cookie->backing_objects))
> + return false;
> +
> + object = hlist_entry(cookie->backing_objects.first,
> + struct fscache_object, cookie_link);
> +
> + return object->cache->ops->check_consistency(object);
> +}
Hmmm... This isn't actually safe. You have to either:
(1) hold cookie->lock whilst touching the object pointer when coming from the
netfs side, or:
(2) set up an operation to do this (as, say, __fscache_alloc_page() does).
The problem is that you have nothing to defend against the object being
withdrawn by the cache under you.
David
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