From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from lists.ozlabs.org (lists.ozlabs.org [112.213.38.117]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 3A742C4332F for ; Wed, 12 Oct 2022 07:53:36 +0000 (UTC) Received: from boromir.ozlabs.org (localhost [IPv6:::1]) by lists.ozlabs.org (Postfix) with ESMTP id 4MnPzL5Hsyz3bmK for ; Wed, 12 Oct 2022 18:53:34 +1100 (AEDT) Authentication-Results: lists.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=linux.alibaba.com (client-ip=47.90.199.17; helo=out199-17.us.a.mail.aliyun.com; envelope-from=jefflexu@linux.alibaba.com; receiver=) Received: from out199-17.us.a.mail.aliyun.com (out199-17.us.a.mail.aliyun.com [47.90.199.17]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 4MnPzB2WvYz2xCj for ; Wed, 12 Oct 2022 18:53:24 +1100 (AEDT) X-Alimail-AntiSpam: AC=PASS;BC=-1|-1;BR=01201311R211e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=ay29a033018046049;MF=jefflexu@linux.alibaba.com;NM=1;PH=DS;RN=8;SR=0;TI=SMTPD_---0VS-qA-q_1665561193; Received: from 30.221.128.220(mailfrom:jefflexu@linux.alibaba.com fp:SMTPD_---0VS-qA-q_1665561193) by smtp.aliyun-inc.com; Wed, 12 Oct 2022 15:53:14 +0800 Message-ID: <28d64f00-e408-9fc2-9506-63c1d8b08b9c@linux.alibaba.com> Date: Wed, 12 Oct 2022 15:53:13 +0800 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:102.0) Gecko/20100101 Thunderbird/102.3.0 Subject: Re: [PATCH 3/5] cachefiles: resend an open request if the read request's object is closed Content-Language: en-US To: Jia Zhu , dhowells@redhat.com, xiang@kernel.org References: <20221011131552.23833-1-zhujia.zj@bytedance.com> <20221011131552.23833-4-zhujia.zj@bytedance.com> From: JeffleXu In-Reply-To: <20221011131552.23833-4-zhujia.zj@bytedance.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-BeenThere: linux-erofs@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Development of Linux EROFS file system List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: linux-fsdevel@vger.kernel.org, linux-cachefs@redhat.com, linux-erofs@lists.ozlabs.org, linux-kernel@vger.kernel.org, yinxin.x@bytedance.com Errors-To: linux-erofs-bounces+linux-erofs=archiver.kernel.org@lists.ozlabs.org Sender: "Linux-erofs" On 10/11/22 9:15 PM, Jia Zhu wrote: > @@ -254,12 +282,18 @@ ssize_t cachefiles_ondemand_daemon_read(struct cachefiles_cache *cache, > * request distribution fair. > */ > xa_lock(&cache->reqs); > - req = xas_find_marked(&xas, UINT_MAX, CACHEFILES_REQ_NEW); > - if (!req && cache->req_id_next > 0) { > - xas_set(&xas, 0); > - req = xas_find_marked(&xas, cache->req_id_next - 1, CACHEFILES_REQ_NEW); > +retry: > + xas_for_each_marked(&xas, req, xa_max, CACHEFILES_REQ_NEW) { > + if (cachefiles_ondemand_skip_req(req)) > + continue; > + break; > } > if (!req) { > + if (cache->req_id_next > 0 && xa_max == ULONG_MAX) { > + xas_set(&xas, 0); > + xa_max = cache->req_id_next - 1; > + goto retry; > + } I would suggest abstracting the "xas_for_each_marked(..., CACHEFILES_REQ_NEW)" part into a helper function to avoid the "goto retry". > @@ -392,8 +434,16 @@ static int cachefiles_ondemand_send_req(struct cachefiles_object *object, > wake_up_all(&cache->daemon_pollwq); > wait_for_completion(&req->done); > ret = req->error; > + kfree(req); > + return ret; > out: > kfree(req); > + /* Reset the object to close state in error handling path. > + * If error occurs after creating the anonymous fd, > + * cachefiles_ondemand_fd_release() will set object to close. > + */ > + if (opcode == CACHEFILES_OP_OPEN) > + cachefiles_ondemand_set_object_close(req->object); This may cause use-after-free since @req has been freed. -- Thanks, Jingbo