[PATCH 8/8] netfs/fscache: Add a memory barrier for FSCACHE_VOLUME_CREATING

[David Howells]

Zizhi Wo <wozizhi at huawei.com> wrote:

> In fscache_create_volume(), there is a missing memory barrier between the
> bit-clearing operation and the wake-up operation. This may cause a
> situation where, after a wake-up, the bit-clearing operation hasn't been
> detected yet, leading to an indefinite wait. The triggering process is as
> follows:
> ...
> By combining the clear and wake operations into clear_and_wake_up_bit() to
> fix this issue.
> 
> Fixes: bfa22da3ed65 ("fscache: Provide and use cache methods to lookup/create/free a volume")
> Signed-off-by: Zizhi Wo <wozizhi at huawei.com>

Acked-by: David Howells <dhowells at redhat.com>