From: Jan Kara <jack@suse.cz>
To: Martin_Zielinski@McAfee.com
Cc: tytso@mit.edu, jack@suse.cz, linux-ext4@vger.kernel.org
Subject: Re: [PATCH 2/2] jbd: fix fsync() tid wraparound bug
Date: Wed, 4 May 2011 23:55:12 +0200 [thread overview]
Message-ID: <20110504215512.GJ6968@quack.suse.cz> (raw)
In-Reply-To: <BCB84D936723884B91E4CC5CA0A7C54AA4F95A9F32@EMEADALEXMB1.corp.nai.org>
On Wed 04-05-11 09:21:04, Martin_Zielinski@McAfee.com wrote:
> Here's an update.
> In my first post I was not aware of the implementation of tid_gt.
> I agree that 2 and a half billion commits on an SD card are - hmph -
> unlikely
<snip>
> gdb) p *journal
> $4 = {j_flags = 16, j_errno = 0, j_sb_buffer = 0xffff88031f156dc8,
> j_superblock = 0xffff88031f876000, j_format_version = 2, j_state_lock = {raw_lock = {
> slock = 2874125135}}, j_barrier_count = 0, j_barrier = {count = {counter = 1}, wait_lock = {
> raw_lock = {slock = 0}}, wait_list = {next = 0xffff88031e6c4638,
> prev = 0xffff88031e6c4638}, owner = 0x0}, j_running_transaction = 0x0,
> j_committing_transaction = 0x0, j_checkpoint_transactions = 0xffff88031bd16b40,
> ...
> j_tail_sequence = 2288011385, j_transaction_sequence = 2288014068,
> j_commit_sequence = 2288014067, j_commit_request = 140530417,
> ...
> j_wbuf = 0xffff88031de98000, j_wbufsize = 512, j_last_sync_writer = 4568,
> j_average_commit_time = 69247, j_private = 0xffff88031fd49400}
<snip>
> (gdb) p ((struct ext3_inode_info*)(0xffff88031f0c0758-0xd0))->i_sync_tid
> $5 = {counter = -2006954411}
> (gdb) p ((struct ext3_inode_info*)(0xffff88031f0c0758-0xd0))->i_datasync_tid
> $3 = {counter = 140530417}
>
> > j_commit_request = 140530417
>
> So it *is* a datasync from sqlite. And your fix will catch it.
> I still don't understand, where this number comes from.
Ok, so i_datasync_tid got corrupted. But look at the numbers in hex:
i_datasync_tid==140530417==0x86052F1
and
i_commit_sequence==2288014067==0x886052F3
So it's a single bit error - we lost the highest bit of the number. Are you
getting the cores from different machines? Otherwise I'd suspect the HW.
If it's not HW I'm at loss what can cause it... You can try moving
i_datasync_tid to a different place in struct ext3_inode_info so that we
can rule out / confirm whether some code external to i_datasync_tid
handling is just causing random memory corruption...
Honza
--
Jan Kara <jack@suse.cz>
SUSE Labs, CR
next prev parent reply other threads:[~2011-05-04 21:55 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <BCB84D936723884B91E4CC5CA0A7C54AA4F6D082BE@EMEADALEXMB1.corp.nai.org>
2011-04-25 23:14 ` 2.6.32 ext3 assertion j_running_transaction != NULL fails in commit.c Ted Ts'o
2011-04-26 0:23 ` [PATCH 1/2] jbd2: fix fsync() tid wraparound bug Theodore Ts'o
2011-04-26 0:23 ` [PATCH 2/2] jbd: " Theodore Ts'o
2011-04-30 17:17 ` Ted Ts'o
2011-05-02 15:07 ` Jan Kara
2011-05-02 18:29 ` Ted Ts'o
2011-05-02 19:04 ` Jan Kara
2011-05-02 21:31 ` Ted Ts'o
2011-05-04 14:21 ` Martin_Zielinski
2011-05-04 21:55 ` Jan Kara [this message]
2011-05-05 14:11 ` Martin_Zielinski
2011-05-05 15:53 ` Jan Kara
2011-05-05 14:55 ` Martin_Zielinski
2011-05-05 15:43 ` Jan Kara
2011-04-26 9:07 ` 2.6.32 ext3 assertion j_running_transaction != NULL fails in commit.c Martin_Zielinski
2011-04-26 12:23 ` Ted Ts'o
2011-04-26 12:45 ` Martin_Zielinski
2011-04-26 17:20 ` Ted Ts'o
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