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 X-Spam-Level: X-Spam-Status: No, score=-11.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 7094FC433E7 for ; Thu, 15 Oct 2020 13:15:26 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0EB922225C for ; Thu, 15 Oct 2020 13:15:26 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727281AbgJONPZ (ORCPT ); Thu, 15 Oct 2020 09:15:25 -0400 Received: from mx2.suse.de ([195.135.220.15]:46698 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726924AbgJONPZ (ORCPT ); Thu, 15 Oct 2020 09:15:25 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id 1E5F3B1DC; Thu, 15 Oct 2020 13:15:23 +0000 (UTC) Received: by quack2.suse.cz (Postfix, from userid 1000) id BCE771E133C; Thu, 15 Oct 2020 15:15:22 +0200 (CEST) Date: Thu, 15 Oct 2020 15:15:22 +0200 From: Jan Kara To: Roman Anufriev Cc: linux-ext4@vger.kernel.org, tytso@mit.edu, jack@suse.cz, dmtrmonakhov@yandex-team.ru Subject: Re: [PATCH 2/2] ext4: export quota journalling mode via sysfs attr quota_mode Message-ID: <20201015131522.GF7037@quack2.suse.cz> References: <1602761572-4713-1-git-send-email-dotdot@yandex-team.ru> <1602761572-4713-2-git-send-email-dotdot@yandex-team.ru> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1602761572-4713-2-git-send-email-dotdot@yandex-team.ru> User-Agent: Mutt/1.10.1 (2018-07-13) Precedence: bulk List-ID: X-Mailing-List: linux-ext4@vger.kernel.org On Thu 15-10-20 14:32:52, Roman Anufriev wrote: > Right now, it is hard to understand what quota journalling type is enabled: > you need to be quite familiar with kernel code and trace it or really > understand what different combinations of fs flags/mount options lead to. > > This patch exports via sysfs attr /sys/fs/ext4//quota_mode current > quota jounalling mode, making it easier to check at a glance/in autotests. > The semantics is similar to ext4 data journalling modes: > > * journalled - quota accounting and journaling are enabled > * writeback - quota accounting is enabled, but journalling is disabled > * none - quota accounting is disabled > * disabled - kernel compiled without CONFIG_QUOTA feature > > Signed-off-by: Roman Anufriev > Reviewed-by: Dmitry Monakhov Hum, I'm not sure about this. The state of quota can be found out with "quotaon -p " (or corresponding quotactl if you need this from C). The only thing you won't learn is journalled / writeback mode and generally you should not care about this although I agree that for fs crash testing purposes you may care. But is that big enough usecase for a new sysfs file when all the information is already available for userspace just not in a convenient form? BTW, I've now realized ext4_any_quota_enabled() has actually misleading name in the sysfs file reports wrong information. It is rather ext4_any_quota_may_be_enabled() since presence of QUOTA mount option only says that quotaon(8) will enable quotas if it is run, not that quota accounting is enabled. sb_any_quota_loaded() tells you if accounting is actually enabled or not (however this can change anytime so that's why we use more relaxed checks for the purpose of journal credit estimates). Honza > --- > fs/ext4/sysfs.c | 22 ++++++++++++++++++++++ > 1 file changed, 22 insertions(+) > > diff --git a/fs/ext4/sysfs.c b/fs/ext4/sysfs.c > index bfabb79..a46487f 100644 > --- a/fs/ext4/sysfs.c > +++ b/fs/ext4/sysfs.c > @@ -36,6 +36,7 @@ typedef enum { > attr_pointer_string, > attr_pointer_atomic, > attr_journal_task, > + attr_quota_mode, > } attr_id_t; > > typedef enum { > @@ -140,6 +141,23 @@ static ssize_t journal_task_show(struct ext4_sb_info *sbi, char *buf) > task_pid_vnr(sbi->s_journal->j_task)); > } > > +static ssize_t quota_mode_show(struct ext4_sb_info *sbi, char *buf) > +{ > +#ifdef CONFIG_QUOTA > + struct super_block *sb = sbi->s_buddy_cache->i_sb; > + > + if (!ext4_any_quota_enabled(sb)) > + return snprintf(buf, PAGE_SIZE, "none\n"); > + > + if (ext4_is_quota_journalled(sb)) > + return snprintf(buf, PAGE_SIZE, "journalled\n"); > + else > + return snprintf(buf, PAGE_SIZE, "writeback\n"); > +#else > + return snprintf(buf, PAGE_SIZE, "disabled\n"); > +#endif > +} > + > #define EXT4_ATTR(_name,_mode,_id) \ > static struct ext4_attr ext4_attr_##_name = { \ > .attr = {.name = __stringify(_name), .mode = _mode }, \ > @@ -248,6 +266,7 @@ EXT4_ATTR(last_error_time, 0444, last_error_time); > EXT4_ATTR(journal_task, 0444, journal_task); > EXT4_RW_ATTR_SBI_UI(mb_prefetch, s_mb_prefetch); > EXT4_RW_ATTR_SBI_UI(mb_prefetch_limit, s_mb_prefetch_limit); > +EXT4_ATTR_FUNC(quota_mode, 0444); > > static unsigned int old_bump_val = 128; > EXT4_ATTR_PTR(max_writeback_mb_bump, 0444, pointer_ui, &old_bump_val); > @@ -296,6 +315,7 @@ static struct attribute *ext4_attrs[] = { > #endif > ATTR_LIST(mb_prefetch), > ATTR_LIST(mb_prefetch_limit), > + ATTR_LIST(quota_mode), > NULL, > }; > ATTRIBUTE_GROUPS(ext4); > @@ -425,6 +445,8 @@ static ssize_t ext4_attr_show(struct kobject *kobj, > return print_tstamp(buf, sbi->s_es, s_last_error_time); > case attr_journal_task: > return journal_task_show(sbi, buf); > + case attr_quota_mode: > + return quota_mode_show(sbi, buf); > } > > return 0; > -- > 2.7.4 > -- Jan Kara SUSE Labs, CR