[Linux-cachefs] [PATCH 2/3] FS-Cache: Reduce cookie ref count if submit fails.

[David Howells]

Milosz Tanski <milosz at adfin.com> wrote:

> The honest answer is I don't know if it know if needs to be unlocked
> before or after. I saw a same pattern with unlocking order inside of
> __fscache_attr_changed in the failure case.

Following the enomem label, I'm calling fscache_unuse_cookie() which does this
without holding the lock in the same function.

I don't think the lock is required because:

 (1) We hold a ref on cookie->n_active so the cookie cannot go away until we
     release it, so calling __fscache_unuse_cookie() without the lock held
     should be fine.

 (2) wake_up_atomic_t() does not access cookie->n_active.  The address is
     merely needed as a key for the waiters to match on.

David