From: Joel Becker Subject: Re: [Ocfs2-devel] [PATCH 2/3] JBD2: Allow feature checks before journal recovery Date: Thu, 12 Aug 2010 10:43:19 -0700 Message-ID: <20100812174318.GD6561@mail.oracle.com> References: <874ofr2myq.fsf@patl.com> <8739vb2mxr.fsf@patl.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: ocfs2-devel@oss.oracle.com, linux-fsdevel@vger.kernel.org, linux-ext4@vger.kernel.org, linux-kernel@vger.kernel.org To: Jan Kara , "Ted Ts'o" , "Patrick J. LoPresti" Return-path: Content-Disposition: inline In-Reply-To: <8739vb2mxr.fsf@patl.com> Sender: linux-fsdevel-owner@vger.kernel.org List-Id: linux-ext4.vger.kernel.org On Thu, Jul 22, 2010 at 03:04:16PM -0700, Patrick J. LoPresti wrote: > Before we start accessing a huge (> 16 TiB) OCFS2 volume, we need to > confirm that its journal supports 64-bit offsets. In particular, we > need to check the journal's feature bits before recovering the journal. > > This is not possible with JBD2 at present, because the journal > superblock (where the feature bits reside) is not loaded from disk until > the journal is recovered. > > This patch loads the journal superblock in > jbd2_journal_check_used_features() if it has not already been loaded, > allowing us to check the feature bits before journal recovery. > > Signed-off-by: Patrick LoPresti Dear jbd2 developers, I've pushed this patch to the merge-window branch of ocfs2.git. I'm ready to send it to Linus, but I need your OK. Joel > diff --git a/fs/jbd2/journal.c b/fs/jbd2/journal.c > index bc2ff59..5cfd8d4 100644 > --- a/fs/jbd2/journal.c > +++ b/fs/jbd2/journal.c > @@ -1365,6 +1365,10 @@ int jbd2_journal_check_used_features (journal_t *journal, unsigned long compat, > > if (!compat && !ro && !incompat) > return 1; > + /* Load journal superblock if it is not loaded yet. */ > + if (journal->j_format_version == 0 && > + journal_get_superblock(journal) != 0) > + return 0; > if (journal->j_format_version == 1) > return 0; > > > _______________________________________________ > Ocfs2-devel mailing list > Ocfs2-devel@oss.oracle.com > http://oss.oracle.com/mailman/listinfo/ocfs2-devel -- Brain: I shall pollute the water supply with this DNAdefibuliser, turning everyone into mindless slaves. Pinky: What about the people who drink bottled water? Brain: Pinky, people who pay 5 dollars for a bottle of water are already mindless slaves. Joel Becker Consulting Software Developer Oracle E-mail: joel.becker@oracle.com Phone: (650) 506-8127