On Thu, Jul 29, 2010 at 05:00:10PM +0400, Vladislav Bolkhovitin wrote: > Christoph Hellwig, on 07/29/2010 12:31 PM wrote: > > My reading of the ext3/jbd code we explicitly wait on I/O completion > > of dependent writes, and only require those to actually be stable > > by issueing a flush. If that wasn't the case the default ext3 > > barriers off behaviour would not only be dangerous on devices with > > volatile write caches, but also on devices that do not have them, > > which in addition to the reading of the code is not what we've seen > > in actual power fail testing, where ext3 does well as long as there > > is no volatile write cache. > > Basically, it is so, but, unfortunately, not absolutely. I've just tried 2 tests on ext4 with iSCSI: Well, this thread was talking about something else (which is how various file systems handle barriers), and not bugs about what happen when a disk disappears from a system due to attachment failure --- but that's fine, we can deal with that here. > Segmentation fault OK, I've looked at your kernel messages, and it looks like the problem comes from this: /* Debugging code just in case the in-memory inode orphan list * isn't empty. The on-disk one can be non-empty if we've * detected an error and taken the fs readonly, but the * in-memory list had better be clean by this point. */ if (!list_empty(&sbi->s_orphan)) dump_orphan_list(sb, sbi); J_ASSERT(list_empty(&sbi->s_orphan)); <==== This is a "should never happen situation", and we crash so we can figure out how we got there. For production kernels, arguably it would probably be better to print a message and a WARN_ON(1), and then not force a crash from a BUG_ON (which is what J_ASSERT is defined to use). Looking at your messages and the ext4_delete_inode() warning, I think I know what caused it. Can you try this patch (attached below) and see if it fixes things for you? > I already reported such issues some time ago, but my reports were > not too much welcomed, so I gave up. Anyway, anybody can easily do > my tests at any time. My apologies. I've gone through the linux-ext4 mailing list logs, and I can't find any mention of this problem from any username @vlnb.net. I'm not sure where you reported it, and I'm sorry we dropped your bug report. All I can say is that we do the best that we can, and our team is relatively small and short-handed. - Ted >From a190d0386e601d58db6d2a6cbf00dc1c17d02136 Mon Sep 17 00:00:00 2001 From: Theodore Ts'o <tytso@xxxxxxx> Date: Thu, 29 Jul 2010 14:54:48 -0400 Subject: [PATCH] patch explicitly-drop-inode-from-orphan-list-on-ext4_delete_inode-failure --- fs/ext4/inode.c | 1 + 1 files changed, 1 insertions(+), 0 deletions(-) diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c index a52d5af..533b607 100644 --- a/fs/ext4/inode.c +++ b/fs/ext4/inode.c @@ -221,6 +221,7 @@ void ext4_delete_inode(struct inode *inode) "couldn't extend journal (err %d)", err); stop_handle: ext4_journal_stop(handle); + ext4_orphan_del(NULL, inode); goto no_delete; } } -- 1.7.0.4 -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
