From mboxrd@z Thu Jan 1 00:00:00 1970 From: Theodore Ts'o Subject: Re: [PATCH] ext4: Ensure that inode is non-NULL before calling ext4_error_inode Date: Wed, 2 Apr 2014 11:32:17 -0400 Message-ID: <20140402153217.GC6901@thunk.org> References: <20140402143630.GB27299@linux.intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: linux-ext4@vger.kernel.org To: Matthew Wilcox Return-path: Received: from imap.thunk.org ([74.207.234.97]:49081 "EHLO imap.thunk.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932247AbaDBPco (ORCPT ); Wed, 2 Apr 2014 11:32:44 -0400 Content-Disposition: inline In-Reply-To: <20140402143630.GB27299@linux.intel.com> Sender: linux-ext4-owner@vger.kernel.org List-ID: On Wed, Apr 02, 2014 at 10:36:30AM -0400, Matthew Wilcox wrote: > > __ext4_handle_dirty_metadata can be called with a NULL inode, but > ext4_error_inode can't. This is supposed to be a "can't happen" path, > so we need to find out whether it can legitimately happen or whether > there's some other bug that is causing this to happen. This prevents > a NULL pointer reference, so it should be included regardless of what > the underlying error is. > > Signed-off-by: Matthew Wilcox This was fixed by the following commit which will be shortly pushed to Linus. Admittedly, I should have done a better job noting it in the commit description (sorry about that): http://git.kernel.org/cgit/linux/kernel/git/tytso/ext4.git/commit/?h=dev&id=0edaa0178ea7142691ae9c10baa42b3e6466d047 In my patch I made sure we printed something so there would be better chance of debugging the problem: + if (inode == NULL) { + pr_err("EXT4: jbd2_journal_dirty_metadata " + "failed: handle type %u started at " + "line %u, credits %u/%u, errcode %d", + handle->h_type, + handle->h_line_no, + handle->h_requested_credits, + handle->h_buffer_credits, err); + return err; + } It turns out this case does happen if we are journalling fs-level metadata, such as block group descriptor. - Ted