On Mon, 13 May 2013 19:26:34 +0800, Zheng Liu <gnehzuil.liu@xxxxxxxxx> wrote: > On Mon, May 13, 2013 at 09:53:25AM +0000, EUNBONG SONG wrote: > > > > > > > Hi all, > > > > > First of all I couldn't reproduce this regression in my sand box. So > > > the following speculation is only my guess. I suspect that the commit > > > (ae4647fb) isn't root cause. It just uncover a potential bug that has > > > been there for a long time. I look at the code, and found two > > > suspicious stuff in jbd2. The first one is in do_get_write_access(). > > > In this function we forgot to lock bh state when we check b_jlist == > > > BJ_Shadow. I generate a patch to fix it, and I really think it is the > > > root cause. Further, in __journal_remove_journal_head() we check > > > b_jlist == BJ_None. But, when this function is called, bh state won't > > > be locked sometimes. So I suspect this is why we hit a BUG in > > > jbd2_journal_put_journal_head(). But I don't have a good solution to > > > fix this until now because I don't know whether we need to lock bh state > > > here, or maybe we should remove this assertation. > > > > > > So, generally, Tony, Eunbong, could you please try the following patch? > > > > > > Thanks in advance, > > > - Zheng > > > > > > Hi, I tested your patch. Unfortunately, the same problem was reproduced. > > Thanks. > > Thanks for trying this patch. Could you please repost the dmesg log for > me? I want to make sure whether the second suspicious stuff causes this > regression or not. Further, that would be great if you could try to > comment this line as the following? AFAIK following assertion was triggered jh->b_transaction != NULL > > diff --git a/fs/jbd2/journal.c b/fs/jbd2/journal.c > index 886ec2f..a9e3779 100644 > --- a/fs/jbd2/journal.c > +++ b/fs/jbd2/journal.c > @@ -2453,7 +2453,7 @@ static void __journal_remove_journal_head(struct > buffer_head *bh) > J_ASSERT_JH(jh, jh->b_transaction == NULL); > J_ASSERT_JH(jh, jh->b_next_transaction == NULL); > J_ASSERT_JH(jh, jh->b_cp_transaction == NULL); > - J_ASSERT_JH(jh, jh->b_jlist == BJ_None); > + /*J_ASSERT_JH(jh, jh->b_jlist == BJ_None);*/ > J_ASSERT_BH(bh, buffer_jbd(bh)); > J_ASSERT_BH(bh, jh2bh(jh) == bh); > BUFFER_TRACE(bh, "remove journal_head"); > > Really thanks, > - Zheng > -- > To unsubscribe from this list: send the line "unsubscribe linux-ext4" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
