From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-qk1-f178.google.com (mail-qk1-f178.google.com [209.85.222.178]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id EF4302F7462 for ; Fri, 17 Apr 2026 06:46:32 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.222.178 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1776408394; cv=none; b=Bbe218/rEANfiXSscZVQifpuOmiA3NhjkztnY9REtpzU0PXpu5vV2pNs0/9qntytHiexoUSMZW75FT+9Gvy1I/63Sqa9JE32LJZeHWqoF7ubWl0ZFovf/Bo3B23cC5a59b17p2F3+rEgJU/H85222YdBsImSAbeEWL9Uv+PfSSM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1776408394; c=relaxed/simple; bh=d4PpKCk3+cY+Ia63Uy2Vt+eoNLKg4rm4l23ANxaSUh8=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=laTxqn5T4OEAKyZFc3524fQc1qktFdvjQiPEfXJvpBMa1/zZg4mUF0UyaOGxVEZrZIkiM/lAMP9tq+TSC1cRIjafvSFzTn+28iD3zHzKKZA54kMtl+6V54WH5t9dQhSxQu9OzPbwsVIy8ecgLeMlTZHQcs4JHHNTMvrH1GBQew0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=gourry.net; spf=pass smtp.mailfrom=gourry.net; dkim=pass (2048-bit key) header.d=gourry.net header.i=@gourry.net header.b=RFsn5e9x; arc=none smtp.client-ip=209.85.222.178 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=gourry.net Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gourry.net Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gourry.net header.i=@gourry.net header.b="RFsn5e9x" Received: by mail-qk1-f178.google.com with SMTP id af79cd13be357-8d6d5e45c43so39812285a.3 for ; Thu, 16 Apr 2026 23:46:32 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gourry.net; s=google; t=1776408392; x=1777013192; darn=lists.linux.dev; h=in-reply-to:content-transfer-encoding:content-disposition :mime-version:references:message-id:subject:cc:to:from:date:from:to :cc:subject:date:message-id:reply-to; bh=hhIjuJ3A3M20AFrPa5BfGVCAhbvvigIUz2GsEPa7gR8=; b=RFsn5e9x6USLb4iZ86KS5oSNHgV5c5un6UpwgaYE0MSOjugGYNIy4HtRe3yfDNXb4A 7QMdAxtPAIsweWXQ/jXu0g+YR4iIvyuZM+80NnI73kB3bn4sqZZRTzMdKkAlGCtNJHn+ 7Q9P2gnGQXrNiGZdJoiBWoM4L1WtPENre9h6XEbuERWMlgKFSbvBjOKzATd9xW94FMbI BRYESo9p/imGFm5TZLm603pV1Op6X1VV3T0WQXfEsRQJ5oDNpEC2V2M3hRxIC4XEOZhQ 28ms4YdrFmXgysaF4BPdKJ/8dtd2Zed5bU46Eco9Aubwb14yAIbEv2SZv/6jP0CuNZ1i 0EMA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1776408392; x=1777013192; h=in-reply-to:content-transfer-encoding:content-disposition :mime-version:references:message-id:subject:cc:to:from:date:x-gm-gg :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=hhIjuJ3A3M20AFrPa5BfGVCAhbvvigIUz2GsEPa7gR8=; b=oyB15xCMrWqNsWDgdW0XkMkC+x+alq2VWoSSqIkWHsnXOhcw9ED5FASMkOP58bDY2B wKWajJcnkq4iSP9kihv7HYomsxfOSI4SZR048F7C7d7nfhBknwQrBSB8ixZ81NhQUG2Q VCvEuqWLC0XAqZpdAy8axkdS2OT4sjwlsPdgb8vkmeIhencXQ+oaSErEWLGecAywZQkT P0vAGQ9S/olzmvL5Wz7g/K6/f6eOgPb7fONt5KdbhNcY1dzHHw+OnRXD2mjjuCxUPDiq OkK6mouJ6zpfYyDe8HUH9Y9A5H0XjD6tffImrBq2ihpR+nvRP1w6wkZ92bdR1i9cVaG3 Us3Q== X-Forwarded-Encrypted: i=1; AFNElJ/jAz0qj5bVBh1tWUI8EcZ6tGB/XIg324bMnLC2DlCk6KlaZ44+usit6CNdeKVesbpgbYukMZk=@lists.linux.dev X-Gm-Message-State: AOJu0YzRCMocgXEcbsujX55re9195Vnt8dUSUqlZnb3h6w2vmWGily0V n272ErOPubNH2m0p2Y9q7E61oT943MjnxzmhpEiOyT0zebKyxeskM5FuGKCX1Trwo+A= X-Gm-Gg: AeBDiesg0K76Vdygxf8V6K+R8Ykaq8LNJy3mkpXs8enQ2GW97AgAv+sm3AjlnY5biT1 OM3CofJkvPSidgYmfTZCruay0vj2zCvAsDKhTxJT7xlJd35lv1Ncjs3c9HBYvcTEjjGzhp2hiYZ CoCwYK9f/rDlzMx7nVpj/Qm6F6Zw1Kd6Y3cADrlLG2w1IssBnaYWuJcZXUiux9T6YOP789m8uim IFjX1yURNCOKiDiXwUOEEb9tNsV0KYJYKv3T1kYxKnCIgYRXwNvd+XUlHDZnyJbUOWjjvHy+Idq jJ2UEcuuMjID0ogjPj6yuxztbpN3tjNzmddRUoszXSSiQwDM7+sU2J0b8So9FiIlO2lhNBhCXR4 FMT6XHR9vAn0f+dATtpgj7O1zT710fs75dPVVBL/OEoOABZxJnPUaAWOzzYcxktnPvPcWIeLQw7 X2bHmfDlB/ixOqx3kgeDOqffFZEyiBNBXSLNoKUf/ikGSF9AmVSqUgT1+geoXRAPXKHSlc72PtK KGbyrJV8rrYcuZDjIpV8ATM5R8Luj8= X-Received: by 2002:a05:620a:4690:b0:8cd:92c5:b3e7 with SMTP id af79cd13be357-8e790407b72mr203408385a.18.1776408391906; Thu, 16 Apr 2026 23:46:31 -0700 (PDT) Received: from gourry-fedora-PF4VCD3F (pool-108-18-109-80.washdc.ftas.verizon.net. [108.18.109.80]) by smtp.gmail.com with ESMTPSA id af79cd13be357-8e7d93c2fffsm42616985a.36.2026.04.16.23.46.28 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 16 Apr 2026 23:46:30 -0700 (PDT) Date: Fri, 17 Apr 2026 02:46:27 -0400 From: Gregory Price To: Joanne Koong Cc: John Groves , "Darrick J. Wong" , Miklos Szeredi , Bernd Schubert , John Groves , Dan Williams , Bernd Schubert , Alison Schofield , John Groves , Jonathan Corbet , Shuah Khan , Vishal Verma , Dave Jiang , Matthew Wilcox , Jan Kara , Alexander Viro , David Hildenbrand , Christian Brauner , Randy Dunlap , Jeff Layton , Amir Goldstein , Jonathan Cameron , Stefan Hajnoczi , Josef Bacik , Bagas Sanjaya , Chen Linxuan , James Morse , Fuad Tabba , Sean Christopherson , Shivank Garg , Ackerley Tng , Aravind Ramesh , Ajay Joshi , "venkataravis@micron.com" , "linux-doc@vger.kernel.org" , "linux-kernel@vger.kernel.org" , "nvdimm@lists.linux.dev" , "linux-cxl@vger.kernel.org" , "linux-fsdevel@vger.kernel.org" , djbw@kernel.org Subject: Re: [PATCH V10 00/10] famfs: port into fuse Message-ID: References: <20260414185740.GA604658@frogsfrogsfrogs> Precedence: bulk X-Mailing-List: nvdimm@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: On Thu, Apr 16, 2026 at 06:24:02PM -0700, Joanne Koong wrote: > On Thu, Apr 16, 2026 at 1:14 PM Gregory Price wrote: > > > > I worry that this discussion is going to turn towards implementing a > > solution grounded in parsing arbitrary formats and how to store them, > > and that is completely detached from why FAMFS went this route in the > > first place. > > > > I question whether the actual issue here lies in the interface APPEARING > > more general purpose than it actually is - and therefore inviting > > attempts to over-genericize it. > > Would you mind clarifying this part? Are you saying that the interface > and logic is *already* generic and usable for other dax-backed > servers, just that everything is *named* famfs but it's not really > famfs specific? Yes. If you just find/replace "famfs" with "dax_iomap", the structures here don't really seem all *that* crazy specific - they're just optimized for memory speeds instead of I/O. There is a circular nature to this - FAMFS figured it out first, in what we think is a reasonably generic way, but we can't know for sure. John, Dan, and Darrick have all proposed reasonable ways to hedge against the obvious fact the interface will not be perfect - which incorporates your BPF proposal along with a reasonably straight forward deprecation path that's not always possible in other arenas. All that while solving a real (and novel) problem. That's actually pretty damn cool. I would urge you to consider these proposals earnestly. ~Gregory