From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 2DFDD13E7FB; Thu, 7 Mar 2024 22:06:09 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1709849170; cv=none; b=SK1yLjZA8VLBJ3HpBrMTS/M1niGgnY4Hif8AbShnbZfIBKfrXPbz7uBeS2xsYBluXYr5tPuU1H5QqRYI7nfM2TtE7QmcdFAQnwhtsqetbTt3VD1+PIDGsH+90PWB51k4EKw25e68UtxH3g0DcvkY1HW/TxLrhkkBTK/WXEKuwdc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1709849170; c=relaxed/simple; bh=3WUDYkcHl8rWSU8JixT9wxsVcPD+MtMgAzpTNdiqdDs=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=mr49DUpAkLX7YrHCe91TB+OWPFEdDcnDbcZFl3twFCQpR7lId4gJBDau4fCIepKTF8S16tFEwOtQsst9mKVZhfWMk0jnasW2gEHuXN17pQW6+zc7k2d72J94iHhHk9csAEArnL7v9Oabu2SzQZoIbqoWdp/y0FwLAqfHSDAPQog= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=CJdiae6p; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="CJdiae6p" Received: by smtp.kernel.org (Postfix) with ESMTPSA id A5059C433F1; Thu, 7 Mar 2024 22:06:09 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1709849169; bh=3WUDYkcHl8rWSU8JixT9wxsVcPD+MtMgAzpTNdiqdDs=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=CJdiae6pmGl2ERLSl6607BBxjBGrOFdVxy+G9D29+qg3+azF9lOQWjmgnfDjl/OIF +FW+kDGtsovMUPjSlsaHXtT+17CjxUmt8cRGv5MG2KZepOhcHqq16E42JBJM/edq/R h/HGriusUiqEfRfFVn/EXiD2faOt+mfCZKSWqHwFBCZzjrMmrngIGRgrPwAF7Aat0A q4VUV+d8Gf3IfqnZ78TcGR2WZZoKJxl0iaJKM90+YK9gGcZPnDh2ruXowdIjMGUV59 zqxQ5JLOwwqrrom6t62B72MdBJs7pcXCjfhuarZ+4KmDmPnyIk0kTJGDUXcOs6X6b4 fRXd2w7HWdC8w== Date: Thu, 7 Mar 2024 14:06:08 -0800 From: "Darrick J. Wong" To: Eric Biggers Cc: Andrey Albershteyn , fsverity@lists.linux.dev, linux-xfs@vger.kernel.org, linux-fsdevel@vger.kernel.org, chandan.babu@oracle.com, Christoph Hellwig Subject: Re: [PATCH v5 10/24] iomap: integrate fs-verity verification into iomap's read path Message-ID: <20240307220608.GT1927156@frogsfrogsfrogs> References: <20240304191046.157464-2-aalbersh@redhat.com> <20240304191046.157464-12-aalbersh@redhat.com> <20240304233927.GC17145@sol.localdomain> Precedence: bulk X-Mailing-List: linux-xfs@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: <20240304233927.GC17145@sol.localdomain> On Mon, Mar 04, 2024 at 03:39:27PM -0800, Eric Biggers wrote: > On Mon, Mar 04, 2024 at 08:10:33PM +0100, Andrey Albershteyn wrote: > > +#ifdef CONFIG_FS_VERITY > > +struct iomap_fsverity_bio { > > + struct work_struct work; > > + struct bio bio; > > +}; > > Maybe leave a comment above that mentions that bio must be the last field. > > > @@ -471,6 +529,7 @@ static loff_t iomap_readahead_iter(const struct iomap_iter *iter, > > * iomap_readahead - Attempt to read pages from a file. > > * @rac: Describes the pages to be read. > > * @ops: The operations vector for the filesystem. > > + * @wq: Workqueue for post-I/O processing (only need for fsverity) > > This should not be here. > > > +#define IOMAP_POOL_SIZE (4 * (PAGE_SIZE / SECTOR_SIZE)) > > + > > static int __init iomap_init(void) > > { > > - return bioset_init(&iomap_ioend_bioset, 4 * (PAGE_SIZE / SECTOR_SIZE), > > - offsetof(struct iomap_ioend, io_inline_bio), > > - BIOSET_NEED_BVECS); > > + int error; > > + > > + error = bioset_init(&iomap_ioend_bioset, IOMAP_POOL_SIZE, > > + offsetof(struct iomap_ioend, io_inline_bio), > > + BIOSET_NEED_BVECS); > > +#ifdef CONFIG_FS_VERITY > > + if (error) > > + return error; > > + > > + error = bioset_init(&iomap_fsverity_bioset, IOMAP_POOL_SIZE, > > + offsetof(struct iomap_fsverity_bio, bio), > > + BIOSET_NEED_BVECS); > > + if (error) > > + bioset_exit(&iomap_ioend_bioset); > > +#endif > > + return error; > > } > > fs_initcall(iomap_init); > > This makes all kernels with CONFIG_FS_VERITY enabled start preallocating memory > for these bios, regardless of whether they end up being used or not. When > PAGE_SIZE==4096 it comes out to about 134 KiB of memory total (32 bios at just > over 4 KiB per bio, most of which is used for the BIO_MAX_VECS bvecs), and it > scales up with PAGE_SIZE such that with PAGE_SIZE==65536 it's about 2144 KiB. > > How about allocating the pool when it's known it's actually going to be used, > similar to what fs/crypto/ does for fscrypt_bounce_page_pool? For example, > there could be a flag in struct fsverity_operations that says whether filesystem > wants the iomap fsverity bioset, and when fs/verity/ sets up the fsverity_info > for any file for the first time since boot, it could call into fs/iomap/ to > initialize the iomap fsverity bioset if needed. I was thinking the same thing. Though I wondered if you want to have a CONFIG_IOMAP_FS_VERITY as well? But that might be tinykernel tetrapyloctomy. --D > BTW, errors from builtin initcalls such as iomap_init() get ignored. So the > error handling logic above does not really work as may have been intended. > > - Eric >