afs: Fix double inc of vnode->cb_break

[ Upstream commit fd711586 ]

When __afs_break_callback() clears the CB_PROMISED flag, it increments
vnode->cb_break to trigger a future refetch of the status and callback -
however it also calls afs_clear_permits(), which also increments
vnode->cb_break.

Fix this by removing the increment from afs_clear_permits().

Whilst we're at it, fix the conditional call to afs_put_permits() as the
function checks to see if the argument is NULL, so the check is redundant.

Fixes: be080a6f ("afs: Overhaul permit caching");
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

fs/afs/security.c

@@ -87,11 +87,9 @@ void afs_clear_permits(struct afs_vnode *vnode)
 	permits = rcu_dereference_protected(vnode->permit_cache,
 					    lockdep_is_held(&vnode->lock));
 	RCU_INIT_POINTER(vnode->permit_cache, NULL);
-	vnode->cb_break++;
 	spin_unlock(&vnode->lock);
 
-	if (permits)
-		afs_put_permits(permits);
+	afs_put_permits(permits);
 }
 
 /*