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 lists.ozlabs.org (lists.ozlabs.org [112.213.38.117]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 9B0EFCDB479 for ; Wed, 24 Jun 2026 14:07:48 +0000 (UTC) Received: from boromir.ozlabs.org (localhost [127.0.0.1]) by lists.ozlabs.org (Postfix) with ESMTP id 4glkKZ6XVjz2yVv; Thu, 25 Jun 2026 00:07:46 +1000 (AEST) Authentication-Results: lists.ozlabs.org; arc=none smtp.remote-ip=213.95.11.211 ARC-Seal: i=1; a=rsa-sha256; d=lists.ozlabs.org; s=201707; t=1782310066; cv=none; b=IqKv3MW6cQRoW+zCm+JWGXuTjei8rCWiuJ1GUb4LXwb6/rEGYfGK4Vbh9ksGn8i5sPpEDX3scz/VO0bPeSh9wFX0WeYpbljVDgBebAGTfTARxES3fv39Kd+wLltB+/WEIurVst6d0g9+7nKFHe9w3GRRKFbH0pcGdAQHyojkKNtNfsv3vSCGxS/yeW681NSqwS5sBz17/XARw1ic0COd/mrIY+fNGf4samgvJa+kythhkTLO/zzoLwodJQ94bIzbqPiE4QFXHOcPIj8wDdrvzfcMHS9j0dn2PnzeqachgK/ru5TzvlPTfJU3D7s9Fs2UAjh671Bp5YEGOwtUAS+Rkg== ARC-Message-Signature: i=1; a=rsa-sha256; d=lists.ozlabs.org; s=201707; t=1782310066; c=relaxed/relaxed; bh=Ad7M3xysLuYYxJa+eQoxMDSPz79ZV7szCzjZry9M5Rg=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=bc0/LeGRVfupQvexq5pmsX/7tn3NSwnhAvRqY00aC3BF7wTUnKI0SJFOyFMvmLk9LcS0Sj5bi8+xaBFJxfIRdU5Lc2G9bJ7VBOTGe999xYwUw4rHwy88SE7x4S0bz9q9m4zUBgsYgwhBZ62lOFAVAsrhoV2ZGRoHU+L1q/AzI22/sRie94fuv97tSVnkgAOUnu31ZUnHmMySlJW3YnRy9MC2GTW7/OIKhn7y591iLtP/8HyODwJSS+kqA07yhByJIeXJLFQua1VKNFP4FhDajl0W2rGW1nF4R3GoB+gSIw+d+Mc9q2WYDyoJVGa/la0QqXXBDV4hEViAEkgleu5hgQ== ARC-Authentication-Results: i=1; lists.ozlabs.org; dmarc=pass (p=none dis=none) header.from=lst.de; spf=pass (client-ip=213.95.11.211; helo=verein.lst.de; envelope-from=hch@lst.de; receiver=lists.ozlabs.org) smtp.mailfrom=lst.de Authentication-Results: lists.ozlabs.org; dmarc=pass (p=none dis=none) header.from=lst.de Authentication-Results: lists.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=lst.de (client-ip=213.95.11.211; helo=verein.lst.de; envelope-from=hch@lst.de; receiver=lists.ozlabs.org) Received: from verein.lst.de (verein.lst.de [213.95.11.211]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 4glkKZ2MmZz2ySg for ; Thu, 25 Jun 2026 00:07:46 +1000 (AEST) Received: by verein.lst.de (Postfix, from userid 2407) id 18A7E68B05; Wed, 24 Jun 2026 16:07:43 +0200 (CEST) Date: Wed, 24 Jun 2026 16:07:42 +0200 From: Christoph Hellwig To: Christian Brauner Cc: Jan Kara , Christoph Hellwig , Jens Axboe , Alexander Viro , linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, Carlos Maiolino , linux-xfs@vger.kernel.org, Chris Mason , David Sterba , linux-btrfs@vger.kernel.org, Theodore Ts'o , linux-ext4@vger.kernel.org, Gao Xiang , linux-erofs@lists.ozlabs.org Subject: Re: [PATCH RFC v2 17/18] fs: look up the superblock via the device table in user_get_super() Message-ID: <20260624140742.GD7692@lst.de> References: <20260616-work-super-bdev_holder_global-v2-0-7df6b864028e@kernel.org> <20260616-work-super-bdev_holder_global-v2-17-7df6b864028e@kernel.org> X-Mailing-List: linux-erofs@lists.ozlabs.org List-Id: List-Help: List-Owner: List-Post: List-Subscribe: , , List-Unsubscribe: Precedence: list MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260616-work-super-bdev_holder_global-v2-17-7df6b864028e@kernel.org> User-Agent: Mutt/1.5.17 (2007-11-01) On Tue, Jun 16, 2026 at 04:08:33PM +0200, Christian Brauner wrote: > user_get_super() still finds the superblock for a device number by > walking the global super_blocks list under sb_lock. Every superblock is > registered in the device table under its s_dev since sget_fc() inserts > it there, including superblocks on anonymous devices, so use the table > instead. So what is the benefit of this? It's not like any of these are heavily used fast paths.