From mboxrd@z Thu Jan 1 00:00:00 1970 From: Coly Li Subject: Re: [RFC PATCH v4 3/3] bcache: reject writeback cache mode for zoned backing device Date: Tue, 2 Jun 2020 00:09:27 +0800 Message-ID: <72c84579-d4be-acb4-7fcb-d773ab847fd5@suse.de> References: <20200522121837.109651-1-colyli@suse.de> <20200522121837.109651-4-colyli@suse.de> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Return-path: Received: from mx2.suse.de ([195.135.220.15]:44504 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726075AbgFAQJd (ORCPT ); Mon, 1 Jun 2020 12:09:33 -0400 In-Reply-To: Content-Language: en-US Sender: linux-bcache-owner@vger.kernel.org List-Id: linux-bcache@vger.kernel.org To: Damien Le Moal , "linux-bcache@vger.kernel.org" Cc: "linux-block@vger.kernel.org" , Hannes Reinecke , Johannes Thumshirn On 2020/5/25 09:26, Damien Le Moal wrote: > On 2020/05/22 21:19, Coly Li wrote: >> Currently we don't support writeback mode for zoned device as backing >> device. So reject it by sysfs interface. >> >> This rejection will be removed after the writeback cache mode support >> for zoned device gets done. >> >> Signed-off-by: Coly Li >> Cc: Damien Le Moal >> Cc: Hannes Reinecke >> Cc: Johannes Thumshirn >> --- >> drivers/md/bcache/sysfs.c | 5 +++++ >> 1 file changed, 5 insertions(+) >> >> diff --git a/drivers/md/bcache/sysfs.c b/drivers/md/bcache/sysfs.c >> index 323276994aab..41bdbc42a17d 100644 >> --- a/drivers/md/bcache/sysfs.c >> +++ b/drivers/md/bcache/sysfs.c >> @@ -359,6 +359,11 @@ STORE(__cached_dev) >> if (v < 0) >> return v; >> >> + if ((unsigned int) v == CACHE_MODE_WRITEBACK) { >> + pr_err("writeback mode is not supported for zoned backing device.\n"); >> + return -ENOTSUPP; >> + } >> + >> if ((unsigned int) v != BDEV_CACHE_MODE(&dc->sb)) { >> SET_BDEV_CACHE_MODE(&dc->sb, v); >> bch_write_bdev_super(dc, NULL); >> > > Do you have a similar check in bcache user tools at format time ? Or is the > cache mode specified only when the bcache device is started ? Yes I do the cache mode check in bcache-tools, and if user sets writeback mode, bcache-tools will inform user and switch it to writethrough mode explicitly. > > Looks good. > > Reviewed-by: Damien Le Moal > Thank you for the review! Coly Li