From: Jan Kara Subject: Re: [PATCH 3/4] jbd2: restart replay without revokes if journal block csum fails Date: Thu, 11 Sep 2014 15:15:11 +0200 Message-ID: <20140911131511.GA30901@quack.suse.cz> References: <20140911002818.10109.51772.stgit@birch.djwong.org> <20140911002838.10109.50948.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 cantor2.suse.de ([195.135.220.15]:35342 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751306AbaIKNPO (ORCPT ); Thu, 11 Sep 2014 09:15:14 -0400 Content-Disposition: inline In-Reply-To: <20140911002838.10109.50948.stgit@birch.djwong.org> Sender: linux-ext4-owner@vger.kernel.org List-ID: On Wed 10-09-14 17:28:38, Darrick J. Wong wrote: > If, during a journal_checksum_v3 replay we encounter a block that > doesn't match its tag in the descriptor block tag, we need to restart > the replay without the revoke table in the hopes of replaying the > newest non-corrupt version of the block that we possibly can. Ho hum, I don't like this. If you just ignore revoke list, you'll happily overwrite freshly allocated data blocks with older metadata. Also when verifying the checksum, we already know the block hasn't been revoked so what's even the benefit of ignoring the revoke list? Honza > Signed-off-by: Darrick J. Wong > --- > fs/jbd2/recovery.c | 19 +++++++++++++++++-- > 1 file changed, 17 insertions(+), 2 deletions(-) > > > diff --git a/fs/jbd2/recovery.c b/fs/jbd2/recovery.c > index 9b329b5..0094d8b 100644 > --- a/fs/jbd2/recovery.c > +++ b/fs/jbd2/recovery.c > @@ -439,6 +439,7 @@ static int do_one_pass(journal_t *journal, > * block offsets): query the superblock. > */ > > +restart_pass: > sb = journal->j_superblock; > next_commit_ID = be32_to_cpu(sb->s_sequence); > next_log_block = be32_to_cpu(sb->s_start); > @@ -585,7 +586,8 @@ static int do_one_pass(journal_t *journal, > /* If the block has been > * revoked, then we're all done > * here. */ > - if (jbd2_journal_test_revoke > + if (!block_error && > + jbd2_journal_test_revoke > (journal, blocknr, > next_commit_ID)) { > brelse(obh); > @@ -599,11 +601,24 @@ static int do_one_pass(journal_t *journal, > be32_to_cpu(tmp->h_sequence))) { > brelse(obh); > success = -EIO; > + if (!block_error) { > + /* If we see a corrupt > + * block, kill the > + * revoke list and > + * restart the replay > + * so that the blocks > + * are as close to > + * accurate as > + * possible. */ > + jbd2_journal_clear_revoke(journal); > + brelse(bh); > + block_error = 1; > + goto restart_pass; > + } > printk(KERN_ERR "JBD2: Invalid " > "checksum recovering " > "block %llu in log\n", > blocknr); > - block_error = 1; > goto skip_write; > } > > > -- > 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 -- Jan Kara SUSE Labs, CR