From: Jan Kara Subject: Re: [PATCH] jbd2: correctly unescape journal data blocks Date: Mon, 17 Mar 2008 16:38:54 +0100 Message-ID: <20080317153854.GC31183@atrey.karlin.mff.cuni.cz> References: <1205606985-22645-1-git-send-email-duaneg@dghda.com> <1205606985-22645-2-git-send-email-duaneg@dghda.com> <1205606985-22645-3-git-send-email-duaneg@dghda.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: sct@redhat.com, akpm@linux-foundation.org, linux-ext4@vger.kernel.org To: Duane Griffin Return-path: Received: from atrey.karlin.mff.cuni.cz ([195.113.31.123]:37731 "EHLO atrey.karlin.mff.cuni.cz" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751667AbYCQPiz (ORCPT ); Mon, 17 Mar 2008 11:38:55 -0400 Content-Disposition: inline In-Reply-To: <1205606985-22645-3-git-send-email-duaneg@dghda.com> Sender: linux-ext4-owner@vger.kernel.org List-ID: > Fix a long-standing typo (predating git) that will cause data corruption if a > journal data block needs unescaping. At the moment the wrong buffer head's data > is being unescaped. > > To test this case mount a filesystem with data=journal, start creating and > deleting a bunch of files containing only JBD2_MAGIC_NUMBER (0xc03b3998), then > pull the plug on the device. Without this patch the files will contain zeros > instead of the correct data after recovery. > > Signed-off-by: Duane Griffin > --- > fs/jbd2/recovery.c | 2 +- > 1 files changed, 1 insertions(+), 1 deletions(-) > > diff --git a/fs/jbd2/recovery.c b/fs/jbd2/recovery.c > index 1464113..5d0405a 100644 > --- a/fs/jbd2/recovery.c > +++ b/fs/jbd2/recovery.c > @@ -535,7 +535,7 @@ static int do_one_pass(journal_t *journal, > memcpy(nbh->b_data, obh->b_data, > journal->j_blocksize); > if (flags & JBD2_FLAG_ESCAPE) { > - *((__be32 *)bh->b_data) = > + *((__be32 *)nbh->b_data) = > cpu_to_be32(JBD2_MAGIC_NUMBER); > } Acked-by: Jan Kara Honza -- Jan Kara SuSE CR Labs