From: Ted Ts'o <tytso@mit.edu>
To: Lukas Czerner <lczerner@redhat.com>
Cc: linux-ext4@vger.kernel.org, rwheeler@redhat.com,
sandeen@redhat.com, adilger@dilger.ca, snitzer@gmail.com
Subject: Re: [PATCH 0/6 v4] Lazy itable initialization for Ext4
Date: Sat, 2 Oct 2010 15:55:35 -0400 [thread overview]
Message-ID: <20101002195535.GM21129@thunk.org> (raw)
In-Reply-To: <alpine.LFD.2.00.1010011752280.2854@dhcp-lab-213.englab.brq.redhat.com>
On Fri, Oct 01, 2010 at 05:58:52PM +0200, Lukas Czerner wrote:
>
> After extensive xfstest-ing I have not been able to reproduce it.
> However, after a while hammering it with other stress test (the one
> I have proposed to test batched discard implementation with) I have
> got a panic due to not up-to-date buffer_head in submit_bh() :
> kernel BUG at fs/buffer.c:2910! - I have been able to reproduce it
> every time (on different BUG_ON sometimes)
I found it --- or at least I found one of the problems.
The call to ext4_unregister_li_request(sb) comes *after* the call to
jbd2_journal_destroy(). If while we are destroying the journal, we
get unlucky and call ext4_init_inode_table(), then we end up creating
a handle after the journal thread is shutdown, during the final call
to jbd2_journal_commit_transaction(), but before
jbd2_journal_destroy() calls jbd2_log_do_checkpoint(), then we end up
waiting forever in jbd2_log_wait_commit().
This shouldn't however lock up the system tight enough that it doesn't
respond to magic sysrq, but I haven't seen that problem since I moved
from 2.6.36-rc3 to 2.6.36-rc6. I do see this problem, which is
definitely a bug.
I am getting a lot of warnings from fs/writeback.c:76 (Dirtiable inode
bdi block != sb bdi block) which I have been commenting out for now,
since it seems to be noisy but otherwise relatively harmless.
I also found a bug in ext4_init_inode_table() where you compare
(num > EXT4_INODES_PER_GROUP(sb)) in ext4_init_inode_table(), which
I'm pretty sure should be (num > sbi->s_itb_per_group) instead.
Regards,
- Ted
next prev parent reply other threads:[~2010-10-02 19:55 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-09-16 12:47 [PATCH 0/6 v4] Lazy itable initialization for Ext4 Lukas Czerner
2010-09-16 12:47 ` [PATCH 1/6] Add helper function for blkdev_issue_zeroout Lukas Czerner
2010-09-16 12:47 ` [PATCH 2/6] Add inititable/noinititable mount options for ext4 Lukas Czerner
2010-09-27 18:35 ` Ted Ts'o
2010-09-16 12:47 ` [PATCH 3/6] Add inode table initialization code for Ext4 Lukas Czerner
2010-09-16 12:47 ` [PATCH 4/6] Use sb_issue_zeroout in setup_new_group_blocks Lukas Czerner
2010-09-29 14:12 ` Lukas Czerner
2010-09-29 14:14 ` Lukas Czerner
2010-10-01 16:00 ` [PATCH 4/6 fixed] " Lukas Czerner
2010-09-16 12:47 ` [PATCH 5/6] Use sb_issue_zeroout in ext4_ext_zeroout Lukas Czerner
2010-09-16 12:47 ` [PATCH 6/6] Add interface to advertise ext4 features in sysfs Lukas Czerner
2010-09-28 4:01 ` [PATCH 0/6 v4] Lazy itable initialization for Ext4 Ted Ts'o
2010-09-28 15:05 ` Ted Ts'o
2010-09-29 13:37 ` Lukas Czerner
2010-10-01 15:58 ` Lukas Czerner
2010-10-02 19:55 ` Ted Ts'o [this message]
2010-10-03 2:43 ` Ted Ts'o
2010-10-04 2:36 ` Ted Ts'o
2010-10-04 7:31 ` Ted Ts'o
2010-10-04 13:14 ` Lukas Czerner
2010-10-04 13:19 ` Lukas Czerner
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