io_uring: fix cancel of deferred reqs with ->files

While trying to cancel requests with ->files, it also should look for
requests in ->defer_list, otherwise it might end up hanging a thread.

Cancel all requests in ->defer_list up to the last request there with
matching ->files, that's needed to follow drain ordering semantics.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/fs/io_uring.c b/fs/io_uring.c
index f703182df2d4d4637486408c13fb299d4de75c08..6129c67b0e3be5c7033e416176e3d208ed3bf5ca 100644 (file)
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -8098,12 +8098,39 @@ static void io_attempt_cancel(struct io_ring_ctx *ctx, struct io_kiocb *req)
        io_timeout_remove_link(ctx, req);
 }
 
+static void io_cancel_defer_files(struct io_ring_ctx *ctx,
+                                 struct files_struct *files)
+{
+       struct io_defer_entry *de = NULL;
+       LIST_HEAD(list);
+
+       spin_lock_irq(&ctx->completion_lock);
+       list_for_each_entry_reverse(de, &ctx->defer_list, list) {
+               if ((de->req->flags & REQ_F_WORK_INITIALIZED)
+                       && de->req->work.files == files) {
+                       list_cut_position(&list, &ctx->defer_list, &de->list);
+                       break;
+               }
+       }
+       spin_unlock_irq(&ctx->completion_lock);
+
+       while (!list_empty(&list)) {
+               de = list_first_entry(&list, struct io_defer_entry, list);
+               list_del_init(&de->list);
+               req_set_fail_links(de->req);
+               io_put_req(de->req);
+               io_req_complete(de->req, -ECANCELED);
+               kfree(de);
+       }
+}
+
 static void io_uring_cancel_files(struct io_ring_ctx *ctx,
                                  struct files_struct *files)
 {
        if (list_empty_careful(&ctx->inflight_list))
                return;
 
+       io_cancel_defer_files(ctx, files);
        /* cancel all at once, should be faster than doing it one by one*/
        io_wq_cancel_cb(ctx->io_wq, io_wq_files_match, files, true);