From mboxrd@z Thu Jan 1 00:00:00 1970 From: Amir Goldstein Subject: Re: Help required for Debugging JBD Date: Wed, 22 Jun 2011 22:29:28 +0300 Message-ID: References: <4E00CC36.80707@gmail.com> <4E02342E.4060203@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: QUOTED-PRINTABLE Cc: linux-ext4@vger.kernel.org To: Niraj Kulkarni Return-path: Received: from mail-ww0-f44.google.com ([74.125.82.44]:51380 "EHLO mail-ww0-f44.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757967Ab1FVT33 convert rfc822-to-8bit (ORCPT ); Wed, 22 Jun 2011 15:29:29 -0400 Received: by wwe5 with SMTP id 5so1180033wwe.1 for ; Wed, 22 Jun 2011 12:29:28 -0700 (PDT) In-Reply-To: <4E02342E.4060203@gmail.com> Sender: linux-ext4-owner@vger.kernel.org List-ID: On Wed, Jun 22, 2011 at 9:27 PM, Niraj Kulkarni wrote: > Hi, > =A0 =A0 Thanks for that SysRq tip. Now I am able to get some logs. > > From OOPS message, it showed an assertion failure on > =A0 =A0J_ASSERT_JH(jh, jh->b_transaction =3D=3D journal->j_committing= _transaction); > > In my code, I've modified journal_commit_transaction such that it col= lects > all buffer_head in a linked list, with their corresponding > buffer numbers in other list. > =A0 =A0 I collect all buffers (data + metadata ) and push them all > simultaneously and pass list of block numbers through a special ioctl= call. > > The problem that I see in my code is that all buffers are handled in = same > way as all data buffers in original code. ie metadata buffers are > getting unfiled instead of refiling. I am not sure what you are saying, but it sounds bad. data buffers and metadata buffers are handled very differently. > > I am attaching my patch. Please can you see and check if that indeed = is > problem here? > JBD is one complicated piece of work (to me), so even if I do find time to review your patch, it's not going to be easy for me. > Also what can be possible solution to it? separation of buffers in 2 = list > (data, metadata) and handling them separately? > Without looking at your patches, I have a lead for you. Lookup the "Journal guided RAID resync" patches. They do something similar to what you describe, for a different purpose= , but they also maintain a list of data blocks and yes, they deal with th= em separately. These patches have been already tested, so they used to be in good shap= e, but are not uptodate. Good luck, Amir. > (Being a kernel noob, my coding does not conform to any standard. So = please > point out any blunders I've committed in my patch) > > Thank You > Niraj > -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" i= n the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html