From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from fhigh4-smtp.messagingengine.com (fhigh4-smtp.messagingengine.com [103.168.172.155]) (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 DBF7F54BD3; Fri, 22 Mar 2024 15:25:20 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=103.168.172.155 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1711121123; cv=none; b=JyXPpUPp8nBo5PAJv0zX6NBdYzSZ7SQdPK1forlv2geRHdEir/k8WoW+UxjiUpQqAkDYCVnz3gQ1NYFUEbK4fGNUn2lfBmj9N36jtLclzB5WzdTolmEWfypjqTDBq21T2Enq1vee1JVWITILXj4m7FER6I8IVO1OF0OeFoW9H/A= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1711121123; c=relaxed/simple; bh=1X+jnJGNJJlRwE895VkKaLxZq0x6oHeflOxLmP1lLnA=; h=Date:From:To:Cc:Subject:Message-ID:MIME-Version:Content-Type: Content-Disposition; b=UJlweqCAnVwThRpjfgyLCke+pHl8CMV2VYMSmbY/Y3rlnexmbtbCDJl4Ew8FZmYyPVMlbNVjwdRhcyeIA7FHnqTf0UKmDXGZHHLq7nQn5doy0l3Jdce1Mm1cVKXTqY/bF5P1xJm4Ef47ukokVa/BlqD2M6IsR/xnV6uERXcLuho= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=joshtriplett.org; spf=pass smtp.mailfrom=joshtriplett.org; dkim=pass (2048-bit key) header.d=joshtriplett.org header.i=@joshtriplett.org header.b=kldN/Bo0; dkim=pass (2048-bit key) header.d=messagingengine.com header.i=@messagingengine.com header.b=YdxfEgCQ; arc=none smtp.client-ip=103.168.172.155 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=joshtriplett.org Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=joshtriplett.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=joshtriplett.org header.i=@joshtriplett.org header.b="kldN/Bo0"; dkim=pass (2048-bit key) header.d=messagingengine.com header.i=@messagingengine.com header.b="YdxfEgCQ" Received: from compute7.internal (compute7.nyi.internal [10.202.2.48]) by mailfhigh.nyi.internal (Postfix) with ESMTP id B778B1140172; Fri, 22 Mar 2024 11:25:19 -0400 (EDT) Received: from mailfrontend1 ([10.202.2.162]) by compute7.internal (MEProxy); Fri, 22 Mar 2024 11:25:19 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d= joshtriplett.org; h=cc:cc:content-type:content-type:date:date :from:from:in-reply-to:message-id:mime-version:reply-to:subject :subject:to:to; s=fm1; t=1711121119; x=1711207519; bh=1X+jnJGNJJ lRwE895VkKaLxZq0x6oHeflOxLmP1lLnA=; b=kldN/Bo0gwIEsV42OSQSXvu1xe x72fbZBsbbdjf/1NuiLKCftcKwXsGva5LvBC58ppp1KR7lX57+1H5ufBk1TAN95t GJZBrJd+OQvrzGS7SDVTjtI5g4loD10b/mvxEGbWFMYzVtqXcOh7GIu45k0Sj0gz XhxVk1oqro+SZ9r+asbbHB0q+9lCyXRzQMsy1sSIsVsGdt2JMv7KwfZ8G8fNUEHi RHohUsRQrqDyDGn4n91wimbdTkNjDhJdKnWZfUOdgVFGjyQpxnZ/9hRTqeFdv3Xw PS4UQWR7sTVapYvF/j+1+TjWRVrIRvDnJ5u6cqPnVWM/3SllODb/bdy96Sdw== DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d= messagingengine.com; h=cc:cc:content-type:content-type:date:date :feedback-id:feedback-id:from:from:in-reply-to:message-id :mime-version:reply-to:subject:subject:to:to:x-me-proxy :x-me-proxy:x-me-sender:x-me-sender:x-sasl-enc; s=fm2; t= 1711121119; x=1711207519; bh=1X+jnJGNJJlRwE895VkKaLxZq0x6oHeflOx LmP1lLnA=; b=YdxfEgCQfuw1X8/VkWKrNCCyBd3OGuNKnTPxNEf7/2HOPYxF7Dh WdeCOPaNnYbNVQP9tW1iV3ssPnzi2KybLo6FtHZlKAllTs0e+AncNG/17dN4WIZv CDOt0e51sCEAjxUOnyF2iQ97mn+IcUYeMsLWdifcbTmuqUc/9GU274pWuc++GtQj SrQZdjRTGUsMJ6A45zOR6LlfZ2Je+OmSZVUwckSLx0zLDARjKSj8BqMahuv4gCkv CQI+2r5RCCn88ESze37jHtDfgJHHtVctkUJ3NhH+9Sjs7RxKPg6recrYO0XQ0+pJ PygSfJbpF8pI13Ww7CvNuTFB2Pp/u1AVPnQ== X-ME-Sender: X-ME-Received: X-ME-Proxy-Cause: gggruggvucftvghtrhhoucdtuddrgedvledruddtvddguddvucetufdoteggodetrfdotf fvucfrrhhofhhilhgvmecuhfgrshhtofgrihhlpdfqfgfvpdfurfetoffkrfgpnffqhgen uceurghilhhouhhtmecufedttdenucesvcftvggtihhpihgvnhhtshculddquddttddmne cujfgurhepfffhvfevuffkgggtugesthdtredttddtvdenucfhrhhomheplfhoshhhucfv rhhiphhlvghtthcuoehjohhshhesjhhoshhhthhrihhplhgvthhtrdhorhhgqeenucggtf frrghtthgvrhhnpeduvdelheettdfgvddvleegueefudegudevffekjeegffefvdeikeeh vdehleekhfenucevlhhushhtvghrufhiiigvpedtnecurfgrrhgrmhepmhgrihhlfhhroh hmpehjohhshhesjhhoshhhthhrihhplhgvthhtrdhorhhg X-ME-Proxy: Feedback-ID: i83e94755:Fastmail Received: by mail.messagingengine.com (Postfix) with ESMTPA; Fri, 22 Mar 2024 11:25:18 -0400 (EDT) Date: Fri, 22 Mar 2024 15:25:16 +0000 From: Josh Triplett To: Alessio Balsini Cc: linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org Subject: FUSE passthrough after opening? Message-ID: 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 I'm really happy to see the FUSE passthrough support merged! I have a use case for which it'd be nice to start FUSE passthrough some time after the initial open: I have a network-backed filesystem, and in some cases I'd like to serve an initial request before retrieving the full file. For instance, for a library .so file, I'd love to service the initial 832-byte read while still downloading the full file. Would it be possible to add support for transitioning an open FUSE file to being backed by passthrough *after* the initial open? Could that work with the current passthrough architecture? (I realize that this might be more complex, as the initial open is a good time to directly substitute a file from the underlying filesystem.) Thanks, Josh Triplett