From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mgamail.intel.com (mgamail.intel.com [192.198.163.14]) (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 7EEA534BA49; Thu, 19 Feb 2026 16:57:47 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=192.198.163.14 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1771520268; cv=none; b=NmdXUe40/8n0L67GIhSgX5yMVnPHZlfmV84/CuIQPQdpNcgJ5W6KLEL/ymWlHlgVu8xvlxl7BwLhNlI4OXCbmnxIX9B8sLAcdH3MroQ5sY6LPwJlFWBEr2YK7A0lqU5DGiToRqFYI7w3in+zDyUcc/yzJQWfZnqFto7IR+vZdPI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1771520268; c=relaxed/simple; bh=keGxv0XW9uGTEDwJr6o3ruRqzxs29dY4le2+vnuYBmc=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=hoQ8I1F6CzAOCuywK+1V78GFVIKY30wWyZ9S/Ab6A6tQyMdbQMIYK5yCRNQ02+VSnWQwCUIc0jtcbvTtk7z2nhtwzcSzbQ+shaYSsGBk1yqUcgkZ/AT3UTHw4AIlfSvn6d7xPHa3rKbHU50sw9qYNHTy0X669id3Z57bk0o54lw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=intel.com; spf=pass smtp.mailfrom=intel.com; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b=TaGDbfVt; arc=none smtp.client-ip=192.198.163.14 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=intel.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=intel.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b="TaGDbfVt" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1771520268; x=1803056268; h=message-id:date:mime-version:subject:to:cc:references: from:in-reply-to:content-transfer-encoding; bh=keGxv0XW9uGTEDwJr6o3ruRqzxs29dY4le2+vnuYBmc=; b=TaGDbfVtzNifoVeqkzBffyt7LVA4kYjFo2CraoWxg4cFtxdZhuDYvSwj qnkBIi882f+oyt8QBE89uqdDfRTZOelyi7s6OOZ6sf5ndoUIRnEBzoB0C 0kpKVl56c9RRY+Kz8Z78kcEUAYiItTgVBgy7esOoNqujt1VhXcm8FUzwI 0eO+IknnbkXudzTN/H3H1n3HClr8tP+El4/l+ERoMZYcWTgSIcimzXrbT AFlquZm9tk9xGUKfNRCOjCVXbK31HRIadykrpU5yQ2aOMaspaOzWtSrHU riztf7SxY5ugCgMgGpYm+AW2buFDkcUx4JDr1XrhPT0uaeFL6XO8v+Dxc Q==; X-CSE-ConnectionGUID: FyslofPgRladKVeR3L9xzw== X-CSE-MsgGUID: QVp4Rv1dSdipKiKrbYMKPg== X-IronPort-AV: E=McAfee;i="6800,10657,11706"; a="72673339" X-IronPort-AV: E=Sophos;i="6.21,300,1763452800"; d="scan'208";a="72673339" Received: from orviesa003.jf.intel.com ([10.64.159.143]) by fmvoesa108.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 19 Feb 2026 08:57:47 -0800 X-CSE-ConnectionGUID: ykm5XSKSSde0hbYU1GXsFQ== X-CSE-MsgGUID: AE6JY0wCRuKWlSheAE0Ngw== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.21,300,1763452800"; d="scan'208";a="218721860" Received: from dnelso2-mobl.amr.corp.intel.com (HELO [10.125.110.20]) ([10.125.110.20]) by ORVIESA003-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 19 Feb 2026 08:57:44 -0800 Message-ID: <512b96fc-c5b0-4388-b640-1a6afd022d80@intel.com> Date: Thu, 19 Feb 2026 09:57:43 -0700 Precedence: bulk X-Mailing-List: linux-cxl@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH V7 11/19] famfs_fuse: Basic fuse kernel ABI enablement for famfs To: John Groves , John Groves , Miklos Szeredi , Dan Williams , Bernd Schubert , Alison Schofield Cc: John Groves , John Groves , Jonathan Corbet , Vishal Verma , Matthew Wilcox , Jan Kara , Alexander Viro , David Hildenbrand , Christian Brauner , "Darrick J . Wong" , Randy Dunlap , Jeff Layton , Amir Goldstein , Jonathan Cameron , Stefan Hajnoczi , Joanne Koong , Josef Bacik , Bagas Sanjaya , James Morse , Fuad Tabba , Sean Christopherson , Shivank Garg , Ackerley Tng , Gregory Price , 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" References: <0100019bd33b1f66-b835e86a-e8ae-443f-a474-02db88f7e6db-000000@email.amazonses.com> <20260118223247.92522-1-john@jagalactic.com> <0100019bd33d6668-75812abd-cb8a-487e-90b9-0fd2b9ad9e89-000000@email.amazonses.com> Content-Language: en-US From: Dave Jiang In-Reply-To: <0100019bd33d6668-75812abd-cb8a-487e-90b9-0fd2b9ad9e89-000000@email.amazonses.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 1/18/26 3:32 PM, John Groves wrote: > From: John Groves > > This patch starts the kernel ABI enablement of famfs in fuse. > > - Kconfig: Add FUSE_FAMFS_DAX config parameter, to control > compilation of famfs within fuse. > - FUSE_DAX_FMAP flag in INIT request/reply > - fuse_conn->famfs_iomap (enable famfs-mapped files) to denote a > famfs-enabled connection > > Reviewed-by: Joanne Koong > Signed-off-by: John Groves Reviewed-by: Dave Jiang > --- > fs/fuse/Kconfig | 14 ++++++++++++++ > fs/fuse/fuse_i.h | 3 +++ > fs/fuse/inode.c | 6 ++++++ > include/uapi/linux/fuse.h | 5 +++++ > 4 files changed, 28 insertions(+) > > diff --git a/fs/fuse/Kconfig b/fs/fuse/Kconfig > index 3a4ae632c94a..5ca9fae62c7b 100644 > --- a/fs/fuse/Kconfig > +++ b/fs/fuse/Kconfig > @@ -76,3 +76,17 @@ config FUSE_IO_URING > > If you want to allow fuse server/client communication through io-uring, > answer Y > + > +config FUSE_FAMFS_DAX > + bool "FUSE support for fs-dax filesystems backed by devdax" > + depends on FUSE_FS > + depends on DEV_DAX > + depends on FS_DAX > + default FUSE_FS > + help > + This enables the fabric-attached memory file system (famfs), > + which enables formatting devdax memory as a file system. Famfs > + is primarily intended for scale-out shared access to > + disaggregated memory. > + > + To enable famfs or other fuse/fs-dax file systems, answer Y > diff --git a/fs/fuse/fuse_i.h b/fs/fuse/fuse_i.h > index 45e108dec771..2839efb219a9 100644 > --- a/fs/fuse/fuse_i.h > +++ b/fs/fuse/fuse_i.h > @@ -921,6 +921,9 @@ struct fuse_conn { > /* Is synchronous FUSE_INIT allowed? */ > unsigned int sync_init:1; > > + /* dev_dax_iomap support for famfs */ > + unsigned int famfs_iomap:1; > + > /* Use io_uring for communication */ > unsigned int io_uring; > > diff --git a/fs/fuse/inode.c b/fs/fuse/inode.c > index ed667920997f..acabf92a11f8 100644 > --- a/fs/fuse/inode.c > +++ b/fs/fuse/inode.c > @@ -1456,6 +1456,10 @@ static void process_init_reply(struct fuse_mount *fm, struct fuse_args *args, > > if (flags & FUSE_REQUEST_TIMEOUT) > timeout = arg->request_timeout; > + > + if (IS_ENABLED(CONFIG_FUSE_FAMFS_DAX) && > + flags & FUSE_DAX_FMAP) > + fc->famfs_iomap = 1; > } else { > ra_pages = fc->max_read / PAGE_SIZE; > fc->no_lock = 1; > @@ -1517,6 +1521,8 @@ static struct fuse_init_args *fuse_new_init(struct fuse_mount *fm) > flags |= FUSE_SUBMOUNTS; > if (IS_ENABLED(CONFIG_FUSE_PASSTHROUGH)) > flags |= FUSE_PASSTHROUGH; > + if (IS_ENABLED(CONFIG_FUSE_FAMFS_DAX)) > + flags |= FUSE_DAX_FMAP; > > /* > * This is just an information flag for fuse server. No need to check > diff --git a/include/uapi/linux/fuse.h b/include/uapi/linux/fuse.h > index c13e1f9a2f12..25686f088e6a 100644 > --- a/include/uapi/linux/fuse.h > +++ b/include/uapi/linux/fuse.h > @@ -240,6 +240,9 @@ > * - add FUSE_COPY_FILE_RANGE_64 > * - add struct fuse_copy_file_range_out > * - add FUSE_NOTIFY_PRUNE > + * > + * 7.46 > + * - Add FUSE_DAX_FMAP capability - ability to handle in-kernel fsdax maps > */ > > #ifndef _LINUX_FUSE_H > @@ -448,6 +451,7 @@ struct fuse_file_lock { > * FUSE_OVER_IO_URING: Indicate that client supports io-uring > * FUSE_REQUEST_TIMEOUT: kernel supports timing out requests. > * init_out.request_timeout contains the timeout (in secs) > + * FUSE_DAX_FMAP: kernel supports dev_dax_iomap (aka famfs) fmaps > */ > #define FUSE_ASYNC_READ (1 << 0) > #define FUSE_POSIX_LOCKS (1 << 1) > @@ -495,6 +499,7 @@ struct fuse_file_lock { > #define FUSE_ALLOW_IDMAP (1ULL << 40) > #define FUSE_OVER_IO_URING (1ULL << 41) > #define FUSE_REQUEST_TIMEOUT (1ULL << 42) > +#define FUSE_DAX_FMAP (1ULL << 43) > > /** > * CUSE INIT request/reply flags