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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 9C82BECAAD8 for ; Tue, 20 Sep 2022 05:05:18 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230040AbiITFFQ (ORCPT ); Tue, 20 Sep 2022 01:05:16 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:48830 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230027AbiITFFN (ORCPT ); Tue, 20 Sep 2022 01:05:13 -0400 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 80D5B46D81 for ; Mon, 19 Sep 2022 22:05:11 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1663650310; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=yrNHPcnH5pHhLlVaGnkT/SYSCwxMBWkCRYx1m0ScmSo=; b=Su3ofSjiTCbiuN9sSXIGpLDOtRXW2YOqC8PGhDTx/aziCDwA7KM9ooyf3eOoqEa2afJA6s vuvirI6F8ZKU4RUCz+GZ7gKhfFu5WWTNDF6mMLOfX0jP+TeX+xj0dcM1Jw8LtEEWveRUuH UPABhBwf001wMY2rTbvr4MHqpb9kiwU= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-516-m6s6kvc5Nhi1ZeJec1vpmA-1; Tue, 20 Sep 2022 01:05:06 -0400 X-MC-Unique: m6s6kvc5Nhi1ZeJec1vpmA-1 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.rdu2.redhat.com [10.11.54.2]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id D8C81185A78B; Tue, 20 Sep 2022 05:05:05 +0000 (UTC) Received: from T590 (ovpn-8-20.pek2.redhat.com [10.72.8.20]) by smtp.corp.redhat.com (Postfix) with ESMTPS id E31B740C6EC2; Tue, 20 Sep 2022 05:05:00 +0000 (UTC) Date: Tue, 20 Sep 2022 13:04:53 +0800 From: Ming Lei To: ZiyangZhang Cc: axboe@kernel.dk, xiaoguang.wang@linux.alibaba.com, linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, joseph.qi@linux.alibaba.com Subject: Re: [PATCH V3 3/7] ublk_drv: define macros for recovery feature and check them Message-ID: References: <20220913041707.197334-1-ZiyangZhang@linux.alibaba.com> <20220913041707.197334-4-ZiyangZhang@linux.alibaba.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220913041707.197334-4-ZiyangZhang@linux.alibaba.com> X-Scanned-By: MIMEDefang 3.1 on 10.11.54.2 Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org On Tue, Sep 13, 2022 at 12:17:03PM +0800, ZiyangZhang wrote: > Define some macros for recovery feature. Especially define a new state: > UBLK_S_DEV_QUIESCED which implies that ublk_device is quiesced > and is ready for recovery. This state can be observed by userspace. > > UBLK_F_USER_RECOVERY implies that: > (1) ublk_drv enables recovery feature. It won't let monitor_work to > automatically abort rqs and release the device. > (2) With a dying ubq_daemon, ublk_drv ends(aborts) rqs issued to > userspace(ublksrv) before crash. > (3) With a dying ubq_daemon, in task work and ublk_queue_rq(), > ublk_drv requeues rqs. > > UBLK_F_USER_RECOVERY_REISSUE implies that: > (1) everything UBLK_F_USER_RECOVERY implies except > (2) With a dying ubq_daemon, ublk_drv requeues rqs issued to > userspace(ublksrv) before crash. > > UBLK_F_USER_RECOVERY_REISSUE is designed for backends which: > (1) tolerates double-writes because ublk_drv may issue the same rq > twice. > (2) does not let frontend users get I/O error. such as read-only FS > and VM backend. > > Signed-off-by: ZiyangZhang > --- > drivers/block/ublk_drv.c | 45 ++++++++++++++++++++++++++++++++++- > include/uapi/linux/ublk_cmd.h | 7 ++++++ > 2 files changed, 51 insertions(+), 1 deletion(-) > > diff --git a/drivers/block/ublk_drv.c b/drivers/block/ublk_drv.c > index 0c6db0978ed0..23337bd7c105 100644 > --- a/drivers/block/ublk_drv.c > +++ b/drivers/block/ublk_drv.c > @@ -49,7 +49,9 @@ > /* All UBLK_F_* have to be included into UBLK_F_ALL */ > #define UBLK_F_ALL (UBLK_F_SUPPORT_ZERO_COPY \ > | UBLK_F_URING_CMD_COMP_IN_TASK \ > - | UBLK_F_NEED_GET_DATA) > + | UBLK_F_NEED_GET_DATA \ > + | UBLK_F_USER_RECOVERY \ > + | UBLK_F_USER_RECOVERY_REISSUE) > > /* All UBLK_PARAM_TYPE_* should be included here */ > #define UBLK_PARAM_TYPE_ALL (UBLK_PARAM_TYPE_BASIC | UBLK_PARAM_TYPE_DISCARD) > @@ -323,6 +325,47 @@ static inline int ublk_queue_cmd_buf_size(struct ublk_device *ub, int q_id) > PAGE_SIZE); > } > > +static inline bool ublk_queue_can_use_recovery( > + struct ublk_queue *ubq) > +{ > + if (ubq->flags & UBLK_F_USER_RECOVERY) > + return true; > + return false; > +} > + > +static inline void ublk_disable_recovery(struct ublk_device *ub) > +{ > + int i; > + > + for (i = 0; i < ub->dev_info.nr_hw_queues; i++) { > + struct ublk_queue *ubq = ublk_get_queue(ub, i); > + > + ubq->flags &= ~UBLK_F_USER_RECOVERY; > + } > +} Flags is supposed to not changed, especially ublk_disable_recovery isn't necessary with my suggestion in the following link: https://lore.kernel.org/linux-block/YylEjEply6y+bs0B@T590/T/#u > + > +static inline bool ublk_can_use_recovery(struct ublk_device *ub) > +{ > + int i; > + > + for (i = 0; i < ub->dev_info.nr_hw_queues; i++) { > + struct ublk_queue *ubq = ublk_get_queue(ub, i); > + > + if (!ublk_queue_can_use_recovery(ubq)) > + return false; > + } > + return true; > +} The above is too tricky, why can't check ub->dev_info & UBLK_F_USER_RECOVERY directly? > + > +static inline bool ublk_queue_can_use_recovery_reissue( > + struct ublk_queue *ubq) > +{ > + if (ublk_queue_can_use_recovery(ubq) && > + (ubq->flags & UBLK_F_USER_RECOVERY_REISSUE)) > + return true; > + return false; > +} > + > static void ublk_free_disk(struct gendisk *disk) > { > struct ublk_device *ub = disk->private_data; > diff --git a/include/uapi/linux/ublk_cmd.h b/include/uapi/linux/ublk_cmd.h > index 677edaab2b66..87204c39f1ee 100644 > --- a/include/uapi/linux/ublk_cmd.h > +++ b/include/uapi/linux/ublk_cmd.h > @@ -17,6 +17,8 @@ > #define UBLK_CMD_STOP_DEV 0x07 > #define UBLK_CMD_SET_PARAMS 0x08 > #define UBLK_CMD_GET_PARAMS 0x09 > +#define UBLK_CMD_START_USER_RECOVERY 0x10 > +#define UBLK_CMD_END_USER_RECOVERY 0x11 > > /* > * IO commands, issued by ublk server, and handled by ublk driver. > @@ -74,9 +76,14 @@ > */ > #define UBLK_F_NEED_GET_DATA (1UL << 2) > > +#define UBLK_F_USER_RECOVERY (1UL << 3) > + > +#define UBLK_F_USER_RECOVERY_REISSUE (1UL << 4) The above are two features. I'd suggest to add UBLK_F_USER_RECOVERY and its implementation first, then add one delta patch for supporting the new feature of UBLK_F_USER_RECOVERY_REISSUE. Not only it is more helpful for reviewing, but also easier to understand the two's difference. thanks, Ming