From: Younger Liu Subject: Re: [PATCH] fs/jbd2: t_updates should increase when start_this_handle() failed in jbd2__journal_restart() Date: Tue, 25 Jun 2013 16:30:18 +0800 Message-ID: <51C9551A.7000900@huawei.com> References: <51C1381A.2@huawei.com> <20130620155555.GE28309@thunk.org> <51C4553B.7010809@huawei.com> <20130623173628.GC16620@thunk.org> Mime-Version: 1.0 Content-Type: text/plain; charset="ISO-8859-1" Content-Transfer-Encoding: 7bit Cc: Andrew Morton , , Ocfs2-Devel , Li Zefan , To: "Theodore Ts'o" Return-path: Received: from szxga03-in.huawei.com ([119.145.14.66]:23567 "EHLO szxga03-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751525Ab3FYIe6 (ORCPT ); Tue, 25 Jun 2013 04:34:58 -0400 In-Reply-To: <20130623173628.GC16620@thunk.org> Sender: linux-ext4-owner@vger.kernel.org List-ID: I will check and test the pacth. I only merge the patch about " jbd2: invalidate handle if jbd2_journal_restart() fails" int my source. But I do not merge the patch about "jbd2: Transaction reservation support...". Does it affect the test? On 2013/6/24 1:36, Theodore Ts'o wrote: > On Fri, Jun 21, 2013 at 09:29:31PM +0800, Younger Liu wrote: >> >> This bug was triggered by the following scenario: >> In ocfs2 file system, allocate a very large disk space for a small file >> with ocfs2_fallocate(), while the journal file size is 32M. >> >> Because there are much many journal blocks needed by jbd2_journal_restart(), >> so that nblocks is greater than journal->j_max_transaction_buffers >> in start_this_handle(), and then return -ENOSPC. > > Ah, I see. I have a patch that should prevent the kernel from > crashing in this situation, and which adds some additional checks to > make sure no one tries to use the handle after jbd2_journal_restart() > fails in this circumstance. > > However, you may want to further pursue a fix in ocfs2 so you don't > actually return ENOSPC to userspace, since it is a very misleading > error message --- it's not that the file system is out of space, but > that the journal is too small for the amount of space that you are > trying to allocate using fallocate(). > > I would think a better way of handling this situation would be to log > a warning message that the journal is probably too small, and then to > break up the fallocate into smaller chunks, so that it can > successfully complete despite the fact that the journal was > unfortunately missized. > > I'll be sending the proposed fix in a moment; could you check and see > if the patch prevents ocfs2/jbd2 from tripping over the assertion > given your test case? > > Thanks, > > - Ted > > . >