From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp06-ext.udag.de (smtp06-ext.udag.de [62.146.106.76]) (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 6E72F334681; Mon, 2 Mar 2026 13:19:28 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=62.146.106.76 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772457569; cv=none; b=C3FjieEXapLcHWSSjSP3+2+A9TAicR0xq0qvow1rQq8x7dG8NwZ4+pmuVa5AIE1w6ggERAmTkQMYrFl6t6IP9nhxJSKahntX//A3KVKT7Nl6pyKU7VgzqQQPkkS+nw4eDzEwdsGzSyk14mJvjSd8LZJfB+BjtLi+K9Sek095HqQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772457569; c=relaxed/simple; bh=szXZa/RffQNkLt0qmFKE+NwKIkBxd7BocfgKPvzRcP0=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=EsU905dtWmKwHaov4PJFX2MS7KA9wTImy4YkYUnXO2A7KhODAy0MM2L6YWCRmILiqOXPysTwZWlv7QjktwsvhRNMss3KQEfc330wd1wDkJxnvWNsaTFN/EFok3xXmJEihvR+OMNFyrMXvZCd0bPGnGcTMLbeJ5Qm7SONp66vJUo= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=birthelmer.de; spf=pass smtp.mailfrom=birthelmer.de; arc=none smtp.client-ip=62.146.106.76 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=birthelmer.de Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=birthelmer.de Received: from localhost (200-143-067-156.ip-addr.inexio.net [156.67.143.200]) by smtp06-ext.udag.de (Postfix) with ESMTPA id CA3C7E032E; Mon, 2 Mar 2026 14:19:18 +0100 (CET) Authentication-Results: smtp06-ext.udag.de; auth=pass smtp.auth=birthelmercom-0001 smtp.mailfrom=horst@birthelmer.de Date: Mon, 2 Mar 2026 14:19:18 +0100 From: Horst Birthelmer To: Miklos Szeredi Cc: Horst Birthelmer , Bernd Schubert , Joanne Koong , Luis Henriques , linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, Horst Birthelmer Subject: Re: Re: Re: [PATCH v6 1/3] fuse: add compound command to combine multiple requests Message-ID: References: <20260226-fuse-compounds-upstream-v6-0-8585c5fcd2fc@ddn.com> <20260226-fuse-compounds-upstream-v6-1-8585c5fcd2fc@ddn.com> 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: On Mon, Mar 02, 2026 at 12:03:35PM +0100, Miklos Szeredi wrote: > On Mon, 2 Mar 2026 at 10:56, Horst Birthelmer wrote: > > > > On Fri, Feb 27, 2026 at 10:45:36AM +0100, Miklos Szeredi wrote: > > > On Thu, 26 Feb 2026 at 17:43, Horst Birthelmer wrote: > > > > + > > > > + unsigned int max_count; > > > > + unsigned int count; > > > > +}; > > > > +/* > > > > + * This is a hint to the fuse server that all requests are complete and it can > > > > + * use automatic decoding and sequential processing from libfuse. > > > > + */ > > > > +#define FUSE_COMPOUND_SEPARABLE (1 << 0) > > > > > > We really need per sub-request flags, not per-compound flags. > > > > > > I.e: > > > > > > FUSE_SUB_IS_ENTRY - this sub request will return a new entry on > > > success (nodeid, filehandle) > > > FUSE_SUB_DEP_ENTRY - this sub request depends on the result of a previous lookup > > > > > > > Couldn't we just save boolean flags in the fuse_args? > > Something like 'bool is_sub_entry:1' and so on? > > Sure, that's fine. > > > If we have the automatic separation and call of requests in the kernel > > when the fuse server returns ENOSYS, I don't see the point in adding this > > to libfuse as well, since there will never be the case, that kernel > > doesn't support compounds but libfuse does. > > It's either the fuse server handles the whole compound, or the kernel does. > > No, I think the library is in a good position to handle compounds, > because that can reduce the complexity in the server while keeping > most of the performance benefits. > > > My point is, we don't need to send that information anywhere. > > We need to send that information in any case. It needs to be part of > the matching done by the server to "recognize" a certain compound, > because the same sequence of operations could have different meaning > if the dependencies are different. OK, if I have to send flags, that are only present if the fuse request is inside a compound then I would suggest that we preface the fuse request with a small compound header, where we store that information. I would not want to change the fuse request, especially not define the same flags for every type of fuse requests. Would that be acceptable? > > Thanks, > Miklos > Thanks, Horst