From mboxrd@z Thu Jan 1 00:00:00 1970 From: Zheng Liu Subject: Re: [PATCH 14/25] e2fsck: only release clusters when shortening a directory during a rehash Date: Mon, 25 Nov 2013 19:09:33 +0800 Message-ID: <20131125110933.GA15056@gmail.com> References: <20131018044854.7339.48457.stgit@birch.djwong.org> <20131018045027.7339.9686.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 mail-pb0-f51.google.com ([209.85.160.51]:41841 "EHLO mail-pb0-f51.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753156Ab3KYLGq (ORCPT ); Mon, 25 Nov 2013 06:06:46 -0500 Received: by mail-pb0-f51.google.com with SMTP id up15so5526744pbc.10 for ; Mon, 25 Nov 2013 03:06:46 -0800 (PST) Content-Disposition: inline In-Reply-To: <20131018045027.7339.9686.stgit@birch.djwong.org> Sender: linux-ext4-owner@vger.kernel.org List-ID: On Thu, Oct 17, 2013 at 09:50:27PM -0700, Darrick J. Wong wrote: > 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. > > Signed-off-by: Darrick J. Wong Reviewed-by: Zheng Liu - Zheng > --- > 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