From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from lindbergh.monkeyblade.net (lindbergh.monkeyblade.net [23.128.96.19]) (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 0182BC2C4 for ; Tue, 17 Oct 2023 05:57:51 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="jZ6IBs+M" Received: from bombadil.infradead.org (bombadil.infradead.org [IPv6:2607:7c80:54:3::133]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 85AFEB6; Mon, 16 Oct 2023 22:57:49 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20210309; h=In-Reply-To:Content-Type:MIME-Version :References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=0hqF3FraEYnMxfUj7zieQAPfPsyUthCr8j2icFG69Sw=; b=jZ6IBs+M3rhjBo/0CdifPyIvYZ /w3tQj91UkMeV2ROPIYtSs/N38BlCH9fKOOSnffUUqMvt+vl5+XkDpXQ/c56dXbcSDzhXXaFEx/aA +QN0bV8EkXFHdk2+suE38nCixOOUNDeQYMUBQrxaANcaHbMxHzTGpfXf2zG8x6jYWtoT9wgLsr9yg +fCmpgKw/U+CnjPDprT0+e7RyGYDu+8nWXD/1I1w0rFYwwWOKKnaCJU1AW/QmvO3Co8OwvnidHQpq v68AtPlCb4cp/0JLwW9eFv20k0KKfF4kDI54s0Wv9f50YI91tTwjFJL0Y7xeNaj1JhbT0WXx57i5+ Vp2D/mRg==; Received: from hch by bombadil.infradead.org with local (Exim 4.96 #2 (Red Hat Linux)) id 1qsd5N-00BL5C-35; Tue, 17 Oct 2023 05:57:45 +0000 Date: Mon, 16 Oct 2023 22:57:45 -0700 From: Christoph Hellwig To: Eric Biggers Cc: Andrey Albershteyn , linux-xfs@vger.kernel.org, linux-fsdevel@vger.kernel.org, fsverity@lists.linux.dev, djwong@kernel.org, david@fromorbit.com, dchinner@redhat.com, willy@infradead.org Subject: Re: [PATCH v3 07/28] fsverity: always use bitmap to track verified status Message-ID: References: <20231006184922.252188-1-aalbersh@redhat.com> <20231006184922.252188-8-aalbersh@redhat.com> <20231011031543.GB1185@sol.localdomain> <20231012072746.GA2100@sol.localdomain> 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: <20231012072746.GA2100@sol.localdomain> X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html X-Spam-Status: No, score=-2.1 required=5.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,RCVD_IN_DNSWL_BLOCKED, SPF_HELO_NONE,SPF_NONE autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net On Thu, Oct 12, 2023 at 12:27:46AM -0700, Eric Biggers wrote: > Currently there are two options: PG_checked and the separate bitmap. I'm not > yet convinced that removing the support for the PG_checked method is a good > change. PG_checked is a nice solution for the cases where it can be used; it > requires no extra memory, no locking, and has no max file size. Also, this > change seems mostly orthogonal to what you're actually trying to accomplish. Given that willy has been on a (IMHO reasonable) quest to kill off as many as possible page flags I'd really like to seize the opportunity and kill PageCheck in fsverity. How big are the downsides of the bitmap vs using the page flags, and do they matter in practice?