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=-10.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=unavailable 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 3486BC11F70 for ; Mon, 12 Jul 2021 07:09:54 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 165AE61175 for ; Mon, 12 Jul 2021 07:09:54 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S241922AbhGLHMa (ORCPT ); Mon, 12 Jul 2021 03:12:30 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35106 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S243738AbhGLHFN (ORCPT ); Mon, 12 Jul 2021 03:05:13 -0400 Received: from casper.infradead.org (casper.infradead.org [IPv6:2001:8b0:10b:1236::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id DAA9EC014C6A; Sun, 11 Jul 2021 23:56:39 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=eP4vUSHmDd/tjsFpgsdSEd4RiF7bQpsRGva+93GUr/E=; b=MmuHUA8D5MmRqXEem8+t09vsuO GI2iJfYJXGFwJhZnPzCoY8yutenWdM8c6CqQdbFszKWvOUfU0qj1MzqOLsrpQa2QtMs4/hVuiN4hy ZmNAq2xO1JqltjJwDQbFGhb1PtfwG04yV7AzGlBjfPE5sQMAmy6fghyx0zTuMQ5DaJgKVtSq/8Zng seP7+fRLX1ZRMASyMK1NUpv4w9mg1J+2/MinWvs25svRwHi9b7tkh/OV6fKWxWk/Ml8PF3VhkXZiu YKEBBnNqb/t0SV3scZ6ewLGT00b+sxzv5RVsGXnM0E/imlgEndReDM3t945tHmLxvgSoR9bSRHe+c BwPxHNLw==; Received: from hch by casper.infradead.org with local (Exim 4.94.2 #2 (Red Hat Linux)) id 1m2pq0-00H1SV-0u; Mon, 12 Jul 2021 06:55:04 +0000 Date: Mon, 12 Jul 2021 07:54:44 +0100 From: Christoph Hellwig To: Matteo Croce Cc: linux-block@vger.kernel.org, linux-fsdevel@vger.kernel.org, Jens Axboe , linux-kernel@vger.kernel.org, Lennart Poettering , Luca Boccassi , Alexander Viro , Damien Le Moal , Tejun Heo , Javier Gonz??lez , Niklas Cassel , Johannes Thumshirn , Hannes Reinecke , Matthew Wilcox , Christoph Hellwig , JeffleXu Subject: Re: [PATCH v4 5/5] loop: raise media_change event Message-ID: References: <20210711175415.80173-1-mcroce@linux.microsoft.com> <20210711175415.80173-6-mcroce@linux.microsoft.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210711175415.80173-6-mcroce@linux.microsoft.com> X-SRS-Rewrite: SMTP reverse-path rewritten from by casper.infradead.org. See http://www.infradead.org/rpr.html Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org So when I said plug into the disk events I did not mean that you need to use all the polling stuff - we can just do the parts required which are the uevents and invalidation with a new little helper like this (needs the actual prototype and kerneldoc of course): diff --git a/block/disk-events.c b/block/disk-events.c index a75931ff5da4..0023ab1559b6 100644 --- a/block/disk-events.c +++ b/block/disk-events.c @@ -163,15 +163,31 @@ void disk_flush_events(struct gendisk *disk, unsigned int mask) spin_unlock_irq(&ev->lock); } +/* + * Tell userland about new events. Only the events listed in @disk->events are + * reported, and only if DISK_EVENT_FLAG_UEVENT is set. Otherwise, events are + * processed internally but never get reported to userland. + */ +static void disk_event_uevent(struct gendisk *disk, unsigned int events) +{ + char *envp[ARRAY_SIZE(disk_uevents) + 1] = { }; + int nr_events = 0, i; + + for (i = 0; i < ARRAY_SIZE(disk_uevents); i++) + if (events & disk->events & (1 << i)) + envp[nr_events++] = disk_uevents[i]; + + if (nr_events) + kobject_uevent_env(&disk_to_dev(disk)->kobj, KOBJ_CHANGE, envp); +} + static void disk_check_events(struct disk_events *ev, unsigned int *clearing_ptr) { struct gendisk *disk = ev->disk; - char *envp[ARRAY_SIZE(disk_uevents) + 1] = { }; unsigned int clearing = *clearing_ptr; unsigned int events; unsigned long intv; - int nr_events = 0, i; /* check events */ events = disk->fops->check_events(disk, clearing); @@ -190,19 +206,8 @@ static void disk_check_events(struct disk_events *ev, spin_unlock_irq(&ev->lock); - /* - * Tell userland about new events. Only the events listed in - * @disk->events are reported, and only if DISK_EVENT_FLAG_UEVENT - * is set. Otherwise, events are processed internally but never - * get reported to userland. - */ - for (i = 0; i < ARRAY_SIZE(disk_uevents); i++) - if ((events & disk->events & (1 << i)) && - (disk->event_flags & DISK_EVENT_FLAG_UEVENT)) - envp[nr_events++] = disk_uevents[i]; - - if (nr_events) - kobject_uevent_env(&disk_to_dev(disk)->kobj, KOBJ_CHANGE, envp); + if (disk->event_flags & DISK_EVENT_FLAG_UEVENT) + disk_event_uevent(disk, events); } /** @@ -281,6 +286,21 @@ bool bdev_check_media_change(struct block_device *bdev) } EXPORT_SYMBOL(bdev_check_media_change); +bool disk_force_media_change(struct gendisk *disk, unsigned int events) +{ + disk_event_uevent(disk, events); + + if (!(events & DISK_EVENT_MEDIA_CHANGE)) + return false; + + if (__invalidate_device(disk->part0, true)) + pr_warn("VFS: busy inodes on changed media %s\n", + disk->disk_name); + set_bit(GD_NEED_PART_SCAN, &disk->state); + return true; +} +EXPORT_SYMBOL_GPL(disk_force_media_change); + /* * Separate this part out so that a different pointer for clearing_ptr can be * passed in for disk_clear_events.