netfs: Move cookie debug ID to struct netfs_cache_resources

Move the cookie debug ID from struct netfs_read_request to struct
netfs_cache_resources and drop the 'cookie_' prefix.  This makes it
available for things that want to use netfs_cache_resources without having
a netfs_read_request.

Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Jeff Layton <jlayton@redhat.com>
cc: linux-cachefs@redhat.com
Link: https://lore.kernel.org/r/162431190784.2908479.13386972676539789127.stgit@warthog.procyon.org.uk/
diff --git a/fs/cachefiles/io.c b/fs/cachefiles/io.c
index b13fb45..ca68bb9 100644
--- a/fs/cachefiles/io.c
+++ b/fs/cachefiles/io.c
@@ -410,7 +410,7 @@ int cachefiles_begin_read_operation(struct netfs_read_request *rreq,
 	rreq->cache_resources.cache_priv = op;
 	rreq->cache_resources.cache_priv2 = file;
 	rreq->cache_resources.ops = &cachefiles_netfs_cache_ops;
-	rreq->cookie_debug_id = object->fscache.debug_id;
+	rreq->cache_resources.debug_id = object->fscache.debug_id;
 	_leave("");
 	return 0;