io-wq: fix hang after cancelling pending hashed work

commit 204361a77f4018627addd4a06877448f088ddfc0 upstream.

Don't forget to update wqe->hash_tail after cancelling a pending work
item, if it was hashed.

Cc: stable@vger.kernel.org # 5.7+
Reported-by: Dmitry Shulyak <yashulyak@gmail.com>
Fixes: 86f3cd1b589a1 ("io-wq: handle hashed writes in chains")
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/fs/io-wq.c b/fs/io-wq.c
index 47c5f3aeb46007eae5a031e825a45a699ace2770..cb9e5a444fba7a3cce76ff1b4f2780395fde8d52 100644 (file)
--- a/fs/io-wq.c
+++ b/fs/io-wq.c
@@ -929,6 +929,24 @@ static bool io_wq_worker_cancel(struct io_worker *worker, void *data)
        return match->nr_running && !match->cancel_all;
 }
 
+static inline void io_wqe_remove_pending(struct io_wqe *wqe,
+                                        struct io_wq_work *work,
+                                        struct io_wq_work_node *prev)
+{
+       unsigned int hash = io_get_work_hash(work);
+       struct io_wq_work *prev_work = NULL;
+
+       if (io_wq_is_hashed(work) && work == wqe->hash_tail[hash]) {
+               if (prev)
+                       prev_work = container_of(prev, struct io_wq_work, list);
+               if (prev_work && io_get_work_hash(prev_work) == hash)
+                       wqe->hash_tail[hash] = prev_work;
+               else
+                       wqe->hash_tail[hash] = NULL;
+       }
+       wq_list_del(&wqe->work_list, &work->list, prev);
+}
+
 static void io_wqe_cancel_pending_work(struct io_wqe *wqe,
                                       struct io_cb_cancel_data *match)
 {
@@ -942,8 +960,7 @@ retry:
                work = container_of(node, struct io_wq_work, list);
                if (!match->fn(work, match->data))
                        continue;
-
-               wq_list_del(&wqe->work_list, node, prev);
+               io_wqe_remove_pending(wqe, work, prev);
                spin_unlock_irqrestore(&wqe->lock, flags);
                io_run_cancel(work, wqe);
                match->nr_pending++;