From: Andreas Dilger Subject: Re: Broken e2fsck i_blocks repair Date: Wed, 1 Sep 2010 16:49:59 -0700 Message-ID: <3B2F6F16-EAC2-435B-89C9-BDB9931541DF@dilger.ca> References: Mime-Version: 1.0 (Apple Message framework v1081) Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 8BIT Cc: ext4 development To: Justin Maggard Return-path: Received: from idcmail-mo2no.shaw.ca ([64.59.134.9]:38586 "EHLO idcmail-mo2no.shaw.ca" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752290Ab0IAXtv convert rfc822-to-8bit (ORCPT ); Wed, 1 Sep 2010 19:49:51 -0400 In-Reply-To: Sender: linux-ext4-owner@vger.kernel.org List-ID: On 2010-09-01, at 16:01, Justin Maggard wrote: > I've mentioned this before on here, but I never verified whether or > not it was actually broken. I have done so today. I manually > modified the block count of a 3TB file using debugfs, then ran e2fsck > on it. e2fsck claimed to repair it, but would throw an error on every > subsequent e2fsck run for the same issue. The reason is > inode->osd2.linux2.l_i_blocks_hi is always set to 0 if e2fsck is told > to fix it. This is an issue in both stable 1.41.12, and in master. > This patch fixes it for me, but is there anything else that needs to > get checked here? It probably makes sense to audit all uses of "i_blocks" to see if they behave similarly badly w.r.t. l_i_blocks_hi. A casual glance indicates that there are a number of places that are similarly broken. I see there is a helper function e2fsck/blknum.c:ext2fs_inode_i_blocks() that should be used for most i_blocks accesses (excluding those places in e2fsck that check for l_i_blocks_hi being non-zero without the appropriate feature flag being set). It might make sense to rename this function ext2fs_inode_i_blocks_get() and add similar ext2fs_inode_i_blocks_set() routine to set it correctly. > diff -urp e2fsprogs-1.41.12/e2fsck/pass1.c e2fsprogs-1.41.12-jm/e2fsck/pass1.c > --- e2fsprogs-1.41.12/e2fsck/pass1.c 2010-05-14 14:51:21.000000000 -0700 > +++ e2fsprogs-1.41.12-jm/e2fsck/pass1.c 2010-09-01 15:54:42.000000000 -0700 > @@ -2044,7 +2044,7 @@ static void check_blocks(e2fsck_t ctx, s > pctx->num = pb.num_blocks; > if (fix_problem(ctx, PR_1_BAD_I_BLOCKS, pctx)) { > inode->i_blocks = pb.num_blocks; > - inode->osd2.linux2.l_i_blocks_hi = 0; > + inode->osd2.linux2.l_i_blocks_hi = (pb.num_blocks >> 32); > dirty_inode++; > } > pctx->num = 0; > > -Justin > -- > To unsubscribe from this list: send the line "unsubscribe linux-ext4" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html Cheers, Andreas