From: =?ISO-8859-15?Q?Luk=E1=A8_Czerner?= Subject: Re: [PATCH 25/31] e2fsck: Only release clusters when shortening a directory during a rehash Date: Thu, 10 Oct 2013 18:13:15 +0200 (CEST) Message-ID: References: <20131001012642.28415.89353.stgit@birch.djwong.org> <20131001012921.28415.90047.stgit@birch.djwong.org> Mime-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Cc: tytso@mit.edu, linux-ext4@vger.kernel.org To: "Darrick J. Wong" Return-path: Received: from mx1.redhat.com ([209.132.183.28]:21800 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756515Ab3JJQNV (ORCPT ); Thu, 10 Oct 2013 12:13:21 -0400 In-Reply-To: <20131001012921.28415.90047.stgit@birch.djwong.org> Sender: linux-ext4-owner@vger.kernel.org List-ID: On Mon, 30 Sep 2013, Darrick J. Wong wrote: > Date: Mon, 30 Sep 2013 18:29:21 -0700 > From: Darrick J. Wong > To: tytso@mit.edu, darrick.wong@oracle.com > Cc: linux-ext4@vger.kernel.org > Subject: [PATCH 25/31] e2fsck: Only release clusters when shortening a > directory during a rehash > > When the rehash process is running on a bigalloc filesystem, it compresses all > the directory entries and hash structures into the beginning of the directory > file and then uses block_iterate3() to free the blocks off the end of the file. > It seems to call ext2fs_block_alloc_stats2() for every block in a cluster, > which is unfortunate because this function allocates and frees entire clusters > (and updates the summary counts accordingly). In this case e2fsck writes out > incorrect summary counts. Looks good. Reviewed-by: Lukas Czerner > > Signed-off-by: Darrick J. Wong > --- > e2fsck/rehash.c | 14 +++++++++++--- > 1 file changed, 11 insertions(+), 3 deletions(-) > > > diff --git a/e2fsck/rehash.c b/e2fsck/rehash.c > index 6ef3568..29da9a1 100644 > --- a/e2fsck/rehash.c > +++ b/e2fsck/rehash.c > @@ -719,10 +719,18 @@ static int write_dir_block(ext2_filsys fs, > /* We don't need this block, so release it */ > e2fsck_read_bitmaps(wd->ctx); > blk = *block_nr; > - ext2fs_unmark_block_bitmap2(wd->ctx->block_found_map, blk); > - ext2fs_block_alloc_stats2(fs, blk, -1); > + /* > + * In theory, we only release blocks from the end of the > + * directory file, so it's fine to clobber a whole cluster at > + * once. > + */ > + if (blk % EXT2FS_CLUSTER_RATIO(fs) == 0) { > + ext2fs_unmark_block_bitmap2(wd->ctx->block_found_map, > + blk); > + ext2fs_block_alloc_stats2(fs, blk, -1); > + wd->cleared++; > + } > *block_nr = 0; > - wd->cleared++; > return BLOCK_CHANGED; > } > > > -- > 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 >