From: Eric Sandeen Subject: Re: [PATCH] resize2fs: clear uninit BG if allocating from new group Date: Thu, 17 Sep 2015 20:54:11 -0400 (EDT) Message-ID: <196754A4-210B-45E7-837A-7955780208E6@redhat.com> References: <55FB41CA.8010003@redhat.com> <20150917235524.GE10390@birch.djwong.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 8BIT Cc: Eric Sandeen , linux-ext4@vger.kernel.org To: "Darrick J. Wong" Return-path: Received: from mx3-phx2.redhat.com ([209.132.183.24]:60466 "EHLO mx3-phx2.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752043AbbIRAyN convert rfc822-to-8bit (ORCPT ); Thu, 17 Sep 2015 20:54:13 -0400 In-Reply-To: <20150917235524.GE10390@birch.djwong.org> Sender: linux-ext4-owner@vger.kernel.org List-ID: On Sep 17, 2015, at 6:55 PM, Darrick J. Wong wrote: > >> On Thu, Sep 17, 2015 at 05:42:18PM -0500, Eric Sandeen wrote: >> If resize2fs_get_alloc_block() allocates from a BLOCK_UNINIT >> group, nothing clears the UNINIT flag, so it is skipped when we >> go to write out modified bitmaps. This leads to post-resize2fs >> e2fsck errors; used blocks in UNINIT groups, not marked in the >> block bitmap. >> >> This shamelessly cuts & pastes clear_block_uninit() into >> resize2fs.c, and my problem goes away. > > Hmm... which test was it that exhibited this error? > r_ext4_small_bg Originally it was claimed that only a gcc change exposed it; I'm still trying to make sense of that. But the pre-resize image exhibits it with any recent resizefs when resized up to 2g as the test does. >> Signed-off-by: Eric Sandeen >> --- >> >> I've kind of lost the thread on resize2fs lately, so maybe this is >> a hack job? At least it highlights the issue, even if it's not >> quite right. Passes "make check" here and seems ok to me... >> >> Thanks, >> -Eric >> >> diff --git a/resize/resize2fs.c b/resize/resize2fs.c >> index 07c6a0c..0f202bd 100644 >> --- a/resize/resize2fs.c >> +++ b/resize/resize2fs.c >> @@ -1614,12 +1614,27 @@ static blk64_t get_new_block(ext2_resize_t rfs) >> } >> } >> >> +static void clear_block_uninit(ext2_filsys fs, dgrp_t group) >> +{ >> + if (!ext2fs_has_group_desc_csum(fs) || >> + !(ext2fs_bg_flags_test(fs, group, EXT2_BG_BLOCK_UNINIT))) >> + return; >> + >> + /* uninit block bitmaps are now initialized in read_bitmaps() */ >> + >> + ext2fs_bg_flags_clear(fs, group, EXT2_BG_BLOCK_UNINIT); >> + ext2fs_group_desc_csum_set(fs, group); >> + ext2fs_mark_super_dirty(fs); >> + ext2fs_mark_bb_dirty(fs); >> +} >> + >> static errcode_t resize2fs_get_alloc_block(ext2_filsys fs, >> blk64_t goal EXT2FS_ATTR((unused)), >> blk64_t *ret) >> { >> ext2_resize_t rfs = (ext2_resize_t) fs->priv_data; >> blk64_t blk; >> + int group; >> >> blk = get_new_block(rfs); >> if (!blk) >> @@ -1632,6 +1647,12 @@ static errcode_t resize2fs_get_alloc_block(ext2_filsys fs, >> >> ext2fs_mark_block_bitmap2(rfs->old_fs->block_map, blk); >> ext2fs_mark_block_bitmap2(rfs->new_fs->block_map, blk); >> + >> + group = ext2fs_group_of_blk2(rfs->old_fs, blk); >> + clear_block_uninit(rfs->old_fs, group); > > Why does the old fs need to have BLOCK_UNINIT cleared? > Same reason we mark the block used in the old fs? TBH I didn't understand why we do that either, but sinc we do.... Eric > --D > >> + group = ext2fs_group_of_blk2(rfs->new_fs, blk); >> + clear_block_uninit(rfs->new_fs, group); >> + >> *ret = (blk64_t) blk; >> return 0; >> } >> >> -- >> 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