On 13 Sep, Ian Dowse wrote:

> For example, if you hold the reference count at 1 while calling the
> cleanup function, it allows that function to safely add and drop
> references, but if that cleanup function has a bug that drops one
> too many references then you end up recursing instead of detecting
> it as a negative reference count. I've found in some other code
> that it works reasonably well to leave the reference count at zero,
> but set a flag to stop further 1->0 transitions from retriggering
> the cleanup. Obviously other approaches will work too.

The cleanup function shouldn't be mucking with the reference count,
which means that the present implementation of nfs_inactive() is broken,
but I think there is already general agreement on that point.  The only
possible exception would be to increase the reference count to pass a
reference to another thread, but that would be a silly thing for a
cleanup function to do, since it would no longer be cleaning up.

We could add a flag that would cause an immediate panic if the cleanup
function fiddled with the reference count as an aid to tracking down
broken code ;-)

To Unsubscribe: send mail to [EMAIL PROTECTED]
with "unsubscribe freebsd-current" in the body of the message

Reply via email to