From: Andreas Dilger Subject: Re: [patch] 48bit extents in e2fsprogs Date: Sat, 16 Sep 2006 12:16:43 -0600 Message-ID: <20060916181643.GI6441@schatzie.adilger.int> References: <20060915120540.GA23824@openx1.frec.bull.fr> <20060915165743.GH6441@schatzie.adilger.int> <20060915181100.GA29801@moule.localdomain> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: linux-ext4@vger.kernel.org, Jean-Pierre Dion Return-path: Received: from mail.clusterfs.com ([206.168.112.78]:7093 "EHLO mail.clusterfs.com") by vger.kernel.org with ESMTP id S1750843AbWIPSQv (ORCPT ); Sat, 16 Sep 2006 14:16:51 -0400 To: Alexandre Ratchov Content-Disposition: inline In-Reply-To: <20060915181100.GA29801@moule.localdomain> Sender: linux-ext4-owner@vger.kernel.org List-Id: linux-ext4.vger.kernel.org On Sep 15, 2006 20:11 +0200, Alexandre Ratchov wrote: > On Fri, Sep 15, 2006 at 10:57:43AM -0600, Andreas Dilger wrote: > > - the check for ee_start_hi and ei_leaf_hi fields (PR_1_EXTENT_HI) needs to > > be fixed (I don't see it changed here) so that it considers that an error > > only if INCOMPAT_64BIT flag is set and the filesystem is > 2^32 blocks. > > That is in e2fsck_ext_block_verify() > > - (FYI) In my definition of PR_1_EXTENT_HI I recently added the PR_PREEN_NOMSG > > flag because users were confused about the "High 16 bits of extent/index > > block set" message even though it is harmless for 32-bit filesystems. > > just to be sure to get it right: we allow 32bit file-systems to have extents > with _hi bits set, right? (and *_hi are ignored) Well, this is an undesirable side-effect of the old 32-bit extents code. e2fsck should just clear the _hi fields for 32-bit filesystems. For larger filesystems it should assume they are valid. That means that the PR_1_EXTENT_HI checks should just be skipped for > 32-bit filesystems. > so we can't simply assume that extents are always 48bit, in which case it > would be enough to just check that they are inside the block group (that > would detect extents with *_hi set as corrupt). For now I wouldn't change the ext4 code. The latest CFS e2fsprogs and kernel code clears the _hi fields correctly, and we can get our users to run an e2fsck before they ever start using ext4-based code (which likely won't be for a year or more) if they have a filesystem which still has _hi values set. Cheers, Andreas -- Andreas Dilger Principal Software Engineer Cluster File Systems, Inc.