From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from zeniv.linux.org.uk (zeniv.linux.org.uk [62.89.141.173]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 80D654CF496; Sun, 18 Oct 2026 02:20:22 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=62.89.141.173 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1792290024; cv=none; b=ZFJ8ETlJKPDrjSMxmF6eL6u7l0lRh/eOAYvgQcy4zR8Cqxapm7Qb+pyPr8gE4V7UZJ7b0GKD/u5ws3f53ySNdjICO0R9pVFi1d9e/9J/KLgVwBRYIq24wm1gA3S0hNRJg/1X01Z9PM+zGjDwwHG7+eJoWgh4ykl0eG/vP+BWlcE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1792290024; c=relaxed/simple; bh=4kwc1QYKBJYhCHoM467+RKJmBKF3hvlYJxRSnGdF+PQ=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=ezXkwoBIKuOO/+ZeX6ioBTk+VEZSbjoMjoGw/UxtUI+uSzLfx6TcyXKS8WXceqoVPHFpuPbSHytcqk9ji8Jk+uTQPPkkQq+h0lROxhBkheoSTcWv0XdKaipq72i71H3SJP1rVwJ6sq63FfAs/+PH94tldw9JLofw2ENAc9nhgpA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=zeniv.linux.org.uk; spf=none smtp.mailfrom=ftp.linux.org.uk; dkim=pass (2048-bit key) header.d=linux.org.uk header.i=@linux.org.uk header.b=foXTMe/B; arc=none smtp.client-ip=62.89.141.173 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=zeniv.linux.org.uk Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=ftp.linux.org.uk Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=linux.org.uk header.i=@linux.org.uk header.b="foXTMe/B" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=linux.org.uk; s=zeniv-20220401; h=Sender:In-Reply-To:Content-Type: MIME-Version:References:Message-ID:Subject:Cc:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=HsdYOKJFCGE7LaEBaLKNX8p+jHBdg59f86rUkY0OYU0=; b=foXTMe/BC7SHF2pYTFnMdSo0YZ i3wFgzpbIDduWet2qDVSh8brvMm9YAeq9c64DdGbiMZmBHJGAxgzeEcZI3oz40MeZxE5dDcd1tAFy sxlLWtGEiUzjuZgpcF5Sc7qaJ5Cqj6CkxtCfjVzzz8nJREQRSEKRYVK7j1LPATOeaPHYPLtQJmx+6 6/dQl/MTkwQbmoNENzn6TbUmvsJQIw1gZa/AXVUMfxmTMUpuUUaP2FYhkp4cjhsxciVEweWUttYGy QlmNKPOIiH3XbYkT9CpWSlTK7flbogsSjGtRcn38fvVz38aQIJxFFPosQv5Zor2W7FA5pqR8sAGGz EhfcT/gw==; Received: from viro by zeniv.linux.org.uk with local (Exim 4.99.5 #2 (Red Hat Linux)) id 1xIGVX-00000002ccL-0YOK; Sun, 18 Oct 2026 02:20:19 +0000 Date: Sun, 18 Oct 2026 03:20:19 +0100 From: Al Viro To: Christian Brauner Cc: linux-fsdevel@vger.kernel.org, "Paul E. McKenney" , NeilBrown , Alexander Larsson , Jan Kara , Jeff Layton , lkmm@lists.linux.dev Subject: Re: [PATCH 3/9] fs: drop the caller's umount(2) reference under mount_lock Message-ID: <20261018022019.GB3535232@ZenIV> References: <20261012-work-mount-gp_on_demand-proposal-v1-0-43f60221a7d0@kernel.org> <20261012-work-mount-gp_on_demand-proposal-v1-3-43f60221a7d0@kernel.org> Precedence: bulk X-Mailing-List: lkmm@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20261012-work-mount-gp_on_demand-proposal-v1-3-43f60221a7d0@kernel.org> Sender: Al Viro On Mon, Oct 12, 2026 at 05:39:16PM +0200, Christian Brauner wrote: > +DEFINE_FREE(mntput_no_expire, struct mount *, if (_T) mntput_no_expire(_T)) You probably want to make it clear in commit message that this is _not_ the decrement-under-lock referred to by the subject... > static int do_umount(struct mount *mnt, int flags) > { > + struct mount *ref __free(mntput_no_expire) = mnt; ... since it's outside of guard(mount_writer()) scope, thankfully (it would obviously break under mount_lock).