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 891072EBDC8; Thu, 4 Sep 2025 23:08:48 +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=1757027331; cv=none; b=dBMiYQCtK8T71vJvWq6rscrO80KCW9HLf/fyEBCv2zy82X8aUzJwrY9eAYCdpOgSPyg08vaREWblLy7bKgg5v78mkJva9R1P4zKUgJeWS30fxDCMN4+SJYxhvs6c1WUb9WewGtXTrSUxaVad3bKJkiCvpi/+q1LeYa1U0+c9PL8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1757027331; c=relaxed/simple; bh=wSaWmZNf1saynh+Yxr0LF+dQuis6OBX7oJn2/NuWmpo=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=ij/DwlSaXk3HyoogffhhFjZpuFDGhDA/aGt5OJia0B/Nejb0BAn5MxSbHzgD8EdDwWEK2FsVn7sFOKSKBk6a/ehEnOFNasNBQrseSDxyv6HNuKFtAmswud3y3wFeKSxx0CU8UKeKOWYZ5pa5OX1xv2z8Z3ravEvGhiX+hFQujos= 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=iWtduqVj; 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="iWtduqVj" 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=IGIvEoAqtuDkRSXpRU77mzhbTzcg6YFarifGx8dUVnA=; b=iWtduqVjwtYURYzGgXJycqlxlF it+u/9BLmB2JKqUpvN5G8QMMTKRttfhPNSKcSEY0wLHMhg1IA87oSHQku6yq5Aq1K25006np8GJyi LAhrKmgjFUc4sHTWi9x5O7Fh6hKteHyux3YYrana889kN14YrjuV35CqSW8OQOZCKLLnvrwpz15rf 9UbLdUpyackW7rxOiPnmW06fqO7Kn4vOWdHm3xkjBDJ/TaWvelbQ+SWqZSOotOhaJdmDl0K4q5lIF Oltkbu4PPtnrBZ/0q3/b3Dti4JY33GUvSocYKbg4rJSn3BxBG+o4laQpbhXA6++wdGzp1mjTQSGUQ tYDyDUSA==; Received: from viro by zeniv.linux.org.uk with local (Exim 4.98.2 #2 (Red Hat Linux)) id 1uuJ4Q-00000009hsf-1a5t; Thu, 04 Sep 2025 23:08:46 +0000 Date: Fri, 5 Sep 2025 00:08:46 +0100 From: Al Viro To: Blake McBride Cc: "linux-fsdevel@vger.kernel.org" , "linux-kernel@vger.kernel.org" , "brauner@kernel.org" , "akpm@linux-foundation.org" , Colby Wes McBride Subject: Re: [RFC] View-Based File System Model with Program-Scoped Isolation Message-ID: <20250904230846.GR39973@ZenIV> References: <20250904220650.GQ39973@ZenIV> 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: Sender: Al Viro On Thu, Sep 04, 2025 at 10:58:12PM +0000, Blake McBride wrote: > Off the cuff, I'd say it is an mv option. It defaults to changing all occurrences, with an option to change it only in the current view. Huh? mv(1) is userland; whatever it does, by definition it boils down to a sequence of system calls. If those "views" of yours are pasted together subtrees of the global forest, you already can do all of that with namespaces; if they are not, you get all kinds of interesting questions about coherency. Which one it is? Before anyone can discuss possible implementations and relative merits thereof, you need to define the semantics of what you want to implement... And frankly, if you are thinking in terms of userland programs (file manglers, etc.) you are going the wrong way - description will have to be on the syscall level.