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 30F51301029 for ; Mon, 25 Aug 2025 16:21:21 +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=1756138884; cv=none; b=Mk0yh7GBSoV/mV6//YN3kotwIQQ0y6ycCNYEtORlOURTo8hulW9o5qeqwbHBOhnOE4W24MJ7iGsGSJ6iLhwzZg7kFRzQT0vd8WpGO41TUjgsMNiTEt/d9gA/Sb8Ps0TJSYYkJ4twMMD9ykv1S10vpmqizCw40eZIHQhq9s376Mw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1756138884; c=relaxed/simple; bh=Z9caLutQEhVyT+pZMKa+xjKkb5GzAdagbjYfBS/W2Yc=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=OEebfsBWHxpHcKBnqxlMt4YKXzfNCDYYQJ35sV/Z/25VvORMbB5OSI8MmOiP/LPcgO42ElSg6C2LTgI/6FjPg+oK8cNwcPRQiEU7cf/TaVjUKrBI5wWaNfguNOmogfJcrqHL/+kqZS/k/bIzkdr1odiICeMhUuX6sE6rGvPKJl0= 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=JgBmagAI; 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="JgBmagAI" 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=ya0ljvtcAK8qBQ3Alu0GIckJZht3u2+psLRiTHbdmQo=; b=JgBmagAIHSpYHDPliqMvHxqDiq A0SU9tlqGuoYHz8nX7Gox5TlHJ0oXRgx0/6lu35wGAyMPTCVYHjMsW8q1X77/IjSNCwU99+f2YtIt 6vfF3FXADvWmYllCvwXPDPiRGGqvZJN7T4fINy8GoiRbRsLcqNPzutSBco2Kd2LKfdH2Dug8iNXbk xAjVehpnjmuC6T7hCSo2AhGZtgfonTPM0WADwJEOgeB+vQFLdSmhZr2AEghix+PseL/n3IqsiN+oe 76Nd2BobiuMJbGPmaDBu22GkjEXZtIHDE+wjRlA2g7xcTfZgjmDyMXtQF79P7wsi5Ypg0UblNq88J 4iXKPbHA==; Received: from viro by zeniv.linux.org.uk with local (Exim 4.98.2 #2 (Red Hat Linux)) id 1uqZwe-0000000GKEK-1MiD; Mon, 25 Aug 2025 16:21:20 +0000 Date: Mon, 25 Aug 2025 17:21:20 +0100 From: Al Viro To: Christian Brauner Cc: linux-fsdevel@vger.kernel.org, jack@suse.cz, torvalds@linux-foundation.org Subject: Re: [PATCH 09/52] put_mnt_ns(): use guards Message-ID: <20250825162120.GN39973@ZenIV> References: <20250825044046.GI39973@ZenIV> <20250825044355.1541941-1-viro@zeniv.linux.org.uk> <20250825044355.1541941-9-viro@zeniv.linux.org.uk> <20250825-hohen-brokkoli-377019b30a94@brauner> Precedence: bulk X-Mailing-List: linux-fsdevel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20250825-hohen-brokkoli-377019b30a94@brauner> Sender: Al Viro On Mon, Aug 25, 2025 at 02:40:53PM +0200, Christian Brauner wrote: > Another thing, did I miss > > commit aab771f34e63ef89e195b63d121abcb55eebfde6 > Author: Al Viro > AuthorDate: Wed Jun 18 18:23:41 2025 -0400 > Commit: Al Viro > CommitDate: Sun Jun 29 19:03:46 2025 -0400 > > take freeing of emptied mnt_namespace to namespace_unlock() > > on the list somehow? I just saw that "emptied_ns" thing for the first > time and was very confused where that came from. I don't see any lore > link attached to the commit message. https://lore.kernel.org/all/20250623045428.1271612-35-viro@zeniv.linux.org.uk/ and https://lore.kernel.org/all/20250630025255.1387419-45-viro@zeniv.linux.org.uk/ in the next iteration of the same patchset, both Cc'd to you. As for the reasons, there are nasty hidden constraints caused by mount notifications; even though all mounts are out of that namespace, we can't free it until the calls of mnt_notify(), which come from notify_mnt_list(), from namespace_unlock(). Better handle it that way than have a recurring headache; besides, it helps with cleaning post-unlock_mount() stuff.