From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 DF20C46D0A4 for ; Thu, 20 Aug 2026 13:40:52 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787233253; cv=none; b=LwD5JR3x4dOBdGQvni8F7WfoqxnrR42UaQRt4aUoJEzq4KKXJcRw43uQU5Ip//td+Fcbjk7CALxBQW976/3s8JliZIgrbiD7nIGKaLeRdj/yiczLvKAjw9JNk4yd7TnXSsp3xBsh/k+yABqhOm5T4mPVgws31K38+jKeHEp+WDI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787233253; c=relaxed/simple; bh=R3VWZSVNSlSrhFc2x1r7ChIkB+iwteVXYZADdS5FYp0=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=nkxd+oWfk+sRt9H5RAlV3K9MTww6NefXzAXfNuJD/UKtOSl+wEuqR5BnG56ez9xDKE2qdvRlRmqv27JEv/feG1Ka13DTdik8zFUBb7boyFwKultAzzWJqR4WCJYQ4mVeluuHZM0g3shglhBv13ilAoesjsGRLO7aKzTa1zGlp9w= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=CTXA8BIS; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="CTXA8BIS" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 8CBB51F00A3A; Thu, 20 Aug 2026 13:40:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1787233252; bh=5C1/sfp0hpxAQ+xYTYGAJFVhzdr//CgmnuBX2/NZFns=; h=Date:From:To:Cc:Subject:References:In-Reply-To; b=CTXA8BISnRoT6XNjF1dM9rUijiJeNjuqx1e6/yWHSEUn7+tvFqgHxvK7yhTPF9Qfg bsIv5jTl2sA6RDFILsrZr7lCOfCVJLZbe0CZNLQxhtVWb8HxktgSnSl7xMelDWOkRb XVQkXlxAueTZzHf2DeCRd8osHg58j8DZZ3g1jvMcGfJR/WkiYCisKVUbi8yfvWgq/K oTh5JpVgVn1HN9d9TvIp3K/ygL6npAiANLQwx7989sGP2Nppa7ge+D58/msktlZuT5 CsSfex4mH8XfUtZ5eDKnVtVbEoxSIcRzLO1EDqy32xEZJH+4IeluI9ewMrD3cWeLtC MNHX8uojwh8gA== Date: Thu, 20 Aug 2026 21:40:46 +0800 From: Gao Xiang To: Christoph Hellwig Cc: Gao Xiang , linux-erofs@lists.ozlabs.org, LKML , Chao Yu Subject: Re: [PATCH v2] erofs: use dedicated meta inodes for file-backed mounts Message-ID: Mail-Followup-To: Christoph Hellwig , Gao Xiang , linux-erofs@lists.ozlabs.org, LKML , Chao Yu References: <20260811080852.29418-1-xiang@kernel.org> <20260811090717.29787-1-xiang@kernel.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: Hi Christoph, On Tue, Aug 18, 2026 at 10:55:47PM -0700, Christoph Hellwig wrote: > On Tue, Aug 11, 2026 at 05:07:17PM +0800, Gao Xiang wrote: > > access on file-backed mounts (although I still don't think it is > > necessary due to the EROFS immutable model). As the result, metadata > > cache won't use the page cache of backing inodes anymore. > > > > The "managed cache" was originally used to cache physical compressed > > data according to the current cache strategy and I/O patterns; since > > file-backed mounts also need to access physical data for metadata > > access, it's natural to reuse the managed cache for this too, providing > > a unique inode for all physical data access. > > This look sane. Any reason to not use the meta inode unconditionally > to simplify the code? I guess you meant avoid using bd_inode page cache? I'm not sure if it simplifies a lot, also like fadvise(WILLNEED) to blkdev can perform to bd_inode too so I think it can still have some benefits. I think bd_inode page cache can be used for filesystems so maybe leave it as-is for now, or maybe a follow-up work if it's really needed. Thanks, Gao Xiang > >