From patchwork Thu Aug 3 13:29:04 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Yu Kuai X-Patchwork-Id: 13340018 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 3C11AC04A6A for ; Thu, 3 Aug 2023 13:34:09 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236083AbjHCNeH (ORCPT ); Thu, 3 Aug 2023 09:34:07 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53534 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235248AbjHCNdl (ORCPT ); Thu, 3 Aug 2023 09:33:41 -0400 Received: from dggsgout11.his.huawei.com (unknown [45.249.212.51]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 0C17C46A8; Thu, 3 Aug 2023 06:32:32 -0700 (PDT) Received: from mail02.huawei.com (unknown [172.30.67.143]) by dggsgout11.his.huawei.com (SkyGuard) with ESMTP id 4RGqXC2twxz4f3lW2; Thu, 3 Aug 2023 21:32:27 +0800 (CST) Received: from huaweicloud.com (unknown [10.175.104.67]) by APP4 (Coremail) with SMTP id gCh0CgAHuKtqrMtkWHLlPQ--.49699S7; Thu, 03 Aug 2023 21:32:28 +0800 (CST) From: Yu Kuai To: song@kernel.org, xni@redhat.com Cc: linux-raid@vger.kernel.org, linux-kernel@vger.kernel.org, yukuai3@huawei.com, yukuai1@huaweicloud.com, yi.zhang@huawei.com, yangerkun@huawei.com Subject: [PATCH -next 03/29] md: add new helpers to suspend/resume array Date: Thu, 3 Aug 2023 21:29:04 +0800 Message-Id: <20230803132930.2742286-4-yukuai1@huaweicloud.com> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20230803132930.2742286-1-yukuai1@huaweicloud.com> References: <20230803132930.2742286-1-yukuai1@huaweicloud.com> MIME-Version: 1.0 X-CM-TRANSID: gCh0CgAHuKtqrMtkWHLlPQ--.49699S7 X-Coremail-Antispam: 1UD129KBjvJXoWxKrykZr47Gryxtw43Gry5twb_yoW7ZF1Up3 yIqFZ5t34UJFZxZw47t3srWa45Ww1rKFWDtrW3Wa13C3Wakr4rWr15Wr15Xr1vka4fAr4D Jw48XayUCry8WFUanT9S1TB71UUUUUUqnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDU0xBIdaVrnRJUUU9C14x267AKxVWrJVCq3wAFc2x0x2IEx4CE42xK8VAvwI8IcIk0 rVWrJVCq3wAFIxvE14AKwVWUJVWUGwA2048vs2IY020E87I2jVAFwI0_JrWl82xGYIkIc2 x26xkF7I0E14v26ryj6s0DM28lY4IEw2IIxxk0rwA2F7IY1VAKz4vEj48ve4kI8wA2z4x0 Y4vE2Ix0cI8IcVAFwI0_Ar0_tr1l84ACjcxK6xIIjxv20xvEc7CjxVAFwI0_Gr1j6F4UJw A2z4x0Y4vEx4A2jsIE14v26rxl6s0DM28EF7xvwVC2z280aVCY1x0267AKxVW0oVCq3wAS 0I0E0xvYzxvE52x082IY62kv0487Mc02F40EFcxC0VAKzVAqx4xG6I80ewAv7VC0I7IYx2 IY67AKxVWUXVWUAwAv7VC2z280aVAFwI0_Gr0_Cr1lOx8S6xCaFVCjc4AY6r1j6r4UM4x0 Y48IcxkI7VAKI48JM4x0x7Aq67IIx4CEVc8vx2IErcIFxwCF04k20xvY0x0EwIxGrwCFx2 IqxVCFs4IE7xkEbVWUJVW8JwC20s026c02F40E14v26r1j6r18MI8I3I0E7480Y4vE14v2 6r106r1rMI8E67AF67kF1VAFwI0_Jw0_GFylIxkGc2Ij64vIr41lIxAIcVC0I7IYx2IY67 AKxVW5JVW7JwCI42IY6xIIjxv20xvEc7CjxVAFwI0_Gr1j6F4UJwCI42IY6xAIw20EY4v2 0xvaj40_Jr0_JF4lIxAIcVC2z280aVAFwI0_Gr0_Cr1lIxAIcVC2z280aVCY1x0267AKxV W8Jr0_Cr1UYxBIdaVFxhVjvjDU0xZFpf9x0JUyv38UUUUU= X-CM-SenderInfo: 51xn3trlr6x35dzhxuhorxvhhfrp/ X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-raid@vger.kernel.org From: Yu Kuai Advantages for new apis: - reconfig_mutex is not required; - the weird logical that suspend array hold 'reconfig_mutex' for mddev_check_recovery() to update superblock is not needed; - the specail handling, 'pers->prepare_suspend', for raid456 is not needed; - It's safe to be called at any time once mddev is allocated, and it's designed to be used from slow path where array configuration is changed; Signed-off-by: Yu Kuai --- drivers/md/md.c | 85 +++++++++++++++++++++++++++++++++++++++++++++++-- drivers/md/md.h | 3 ++ 2 files changed, 86 insertions(+), 2 deletions(-) diff --git a/drivers/md/md.c b/drivers/md/md.c index 89f5175b1295..3c98f253b980 100644 --- a/drivers/md/md.c +++ b/drivers/md/md.c @@ -442,12 +442,22 @@ void mddev_suspend(struct mddev *mddev) lockdep_is_held(&mddev->reconfig_mutex)); WARN_ON_ONCE(thread && current == thread->tsk); - if (mddev->suspended++) + + /* can't concurrent with __mddev_suspend() and __mddev_resume() */ + mutex_lock(&mddev->suspend_mutex); + if (mddev->suspended++) { + mutex_unlock(&mddev->suspend_mutex); return; + } + wake_up(&mddev->sb_wait); set_bit(MD_ALLOW_SB_UPDATE, &mddev->flags); percpu_ref_kill(&mddev->active_io); + /* + * TODO: cleanup 'pers->prepare_suspend after all callers are replaced + * by __mddev_suspend(). + */ if (mddev->pers && mddev->pers->prepare_suspend) mddev->pers->prepare_suspend(mddev); @@ -458,14 +468,21 @@ void mddev_suspend(struct mddev *mddev) del_timer_sync(&mddev->safemode_timer); /* restrict memory reclaim I/O during raid array is suspend */ mddev->noio_flag = memalloc_noio_save(); + + mutex_unlock(&mddev->suspend_mutex); } EXPORT_SYMBOL_GPL(mddev_suspend); void mddev_resume(struct mddev *mddev) { lockdep_assert_held(&mddev->reconfig_mutex); - if (--mddev->suspended) + + /* can't concurrent with __mddev_suspend() and __mddev_resume() */ + mutex_lock(&mddev->suspend_mutex); + if (--mddev->suspended) { + mutex_unlock(&mddev->suspend_mutex); return; + } /* entred the memalloc scope from mddev_suspend() */ memalloc_noio_restore(mddev->noio_flag); @@ -476,9 +493,72 @@ void mddev_resume(struct mddev *mddev) set_bit(MD_RECOVERY_NEEDED, &mddev->recovery); md_wakeup_thread(mddev->thread); md_wakeup_thread(mddev->sync_thread); /* possibly kick off a reshape */ + + mutex_unlock(&mddev->suspend_mutex); } EXPORT_SYMBOL_GPL(mddev_resume); +void __mddev_suspend(struct mddev *mddev) +{ + + /* + * hold reconfig_mutex to wait for normal io will deadlock, because + * other context can't update super_block, and normal io can rely on + * updating super_block. + */ + lockdep_assert_not_held(&mddev->reconfig_mutex); + + mutex_lock(&mddev->suspend_mutex); + + if (mddev->suspended) { + WRITE_ONCE(mddev->suspended, mddev->suspended + 1); + mutex_unlock(&mddev->suspend_mutex); + return; + } + + percpu_ref_kill(&mddev->active_io); + wait_event(mddev->sb_wait, percpu_ref_is_zero(&mddev->active_io)); + + /* + * For raid456, io might be waiting for reshape to make progress, + * allow new reshape to start while waiting for io to be done to + * prevent deadlock. + */ + WRITE_ONCE(mddev->suspended, mddev->suspended + 1); + + del_timer_sync(&mddev->safemode_timer); + /* restrict memory reclaim I/O during raid array is suspend */ + mddev->noio_flag = memalloc_noio_save(); + + mutex_unlock(&mddev->suspend_mutex); +} +EXPORT_SYMBOL_GPL(__mddev_suspend); + +void __mddev_resume(struct mddev *mddev) +{ + lockdep_assert_not_held(&mddev->reconfig_mutex); + + mutex_lock(&mddev->suspend_mutex); + WRITE_ONCE(mddev->suspended, mddev->suspended - 1); + if (mddev->suspended) { + mutex_unlock(&mddev->suspend_mutex); + return; + } + + /* entred the memalloc scope from __mddev_suspend() */ + memalloc_noio_restore(mddev->noio_flag); + + percpu_ref_resurrect(&mddev->active_io); + wake_up(&mddev->sb_wait); + + set_bit(MD_RECOVERY_NEEDED, &mddev->recovery); + md_wakeup_thread(mddev->thread); + md_wakeup_thread(mddev->sync_thread); /* possibly kick off a reshape */ + + mutex_unlock(&mddev->suspend_mutex); +} +EXPORT_SYMBOL_GPL(__mddev_resume); + /* * Generic flush handling for md */ @@ -666,6 +746,7 @@ int mddev_init(struct mddev *mddev) mutex_init(&mddev->open_mutex); mutex_init(&mddev->reconfig_mutex); mutex_init(&mddev->sync_mutex); + mutex_init(&mddev->suspend_mutex); mutex_init(&mddev->bitmap_info.mutex); INIT_LIST_HEAD(&mddev->disks); INIT_LIST_HEAD(&mddev->all_mddevs); diff --git a/drivers/md/md.h b/drivers/md/md.h index 82d2c4ed9aca..32bfe0fe0d97 100644 --- a/drivers/md/md.h +++ b/drivers/md/md.h @@ -308,6 +308,7 @@ struct mddev { unsigned long sb_flags; int suspended; + struct mutex suspend_mutex; struct percpu_ref active_io; int ro; int sysfs_active; /* set when sysfs deletes @@ -803,6 +804,8 @@ extern void md_rdev_clear(struct md_rdev *rdev); extern void md_handle_request(struct mddev *mddev, struct bio *bio); extern void mddev_suspend(struct mddev *mddev); extern void mddev_resume(struct mddev *mddev); +extern void __mddev_suspend(struct mddev *mddev); +extern void __mddev_resume(struct mddev *mddev); extern void md_reload_sb(struct mddev *mddev, int raid_disk); extern void md_update_sb(struct mddev *mddev, int force);