Re: ext3: slow symlink corruption on umount...

[Arthur Jones <ajones@riverbed.com>]

On Thu, Oct 30, 2008 at 02:34:00PM -0700, Arthur Jones wrote:
> Hi Eric,  ...
> 
> On Thu, Oct 30, 2008 at 11:03:49AM -0700, Eric Sandeen wrote:
> > [...]
> > Something is definitely racy here; in my simple testcase I get failures
> > maybe 30-50% of the time...
> 
> Some more info: in the working case, the inodes are put
> back on sb->s_dirty at then next ext3_sync_fs() call:
> 
> __fsync_super -> DQUOT_SYNC -> ext3_sync_fs -> log_wait_commit
> 
> In the failing case, journal_start_commit returns 0 in ext_sync_fs
> and the inodes disappear into never-never land...

More details, these are dumps at __log_start_commit in the
call chain described above, the first column is the failing
case, the next column is working case, t_expires is the delta
from the time the dump was taken:

        journal->j_flags                                0x10    0x10
        journal->j_tail_sequence                         515     519
        journal->j_transaction_sequence                  517     522
        journal->j_commit_sequence                       514     519
        journal->j_commit_request                        516     520

        journal->j_running_transaction->t_tid            516     521
        journal->j_running_transaction->t_state            0       0
        journal->j_running_transaction->t_updates          0       0
        journal->j_running_transaction->t_handle_count 27305   27344
        journal->j_running_transaction->t_expires       -566      28

Can you tell from this whether the transactions
are messed up or whether we're just missing a
wake_up?  Any other info you'd like to see?

Arthur