io_uring: fix drain with rsrc CQEs

Resource emitted CQEs are not bound to requests, so fix up counters used
for DRAIN/defer logic.

Fixes: b60c8dce ("io_uring: preparation for rsrc tagging")
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/2b32f5f0a40d5928c3466d028f936e167f0654be.1619536280.git.asml.silence@gmail.comSigned-off-by: Jens Axboe <axboe@kernel.dk>

fs/io_uring.c

@@ -7539,6 +7539,7 @@ static void __io_rsrc_put_work(struct io_rsrc_node *ref_node)
 			io_ring_submit_lock(ctx, lock_ring);
 			spin_lock_irqsave(&ctx->completion_lock, flags);
 			io_cqring_fill_event(ctx, prsrc->tag, 0, 0);
+			ctx->cq_extra++;
 			io_commit_cqring(ctx);
 			spin_unlock_irqrestore(&ctx->completion_lock, flags);
 			io_cqring_ev_posted(ctx);