[Ocfs2-devel] [PATCH -v2 1/3] jbd2: Use atomic variables to avoid taking t_handle_lock in jbd2_journal_stop
Ted Ts'o
tytso at mit.edu
Mon Aug 9 12:05:13 PDT 2010
On Mon, Aug 09, 2010 at 07:02:16PM +0200, Jan Kara wrote:
> spin_lock(&journal->j_state_lock);
> spin_lock(&transaction->t_handle_lock);
> - transaction->t_outstanding_credits -= handle->h_buffer_credits;
> - transaction->t_updates--;
> -
> - if (!transaction->t_updates)
> + atomic_sub(handle->h_buffer_credits,
> + &transaction->t_outstanding_credits);
> + if (atomic_dec_and_test(&transaction->t_updates))
>
> After this a transaction can disappear so subsequent
> __jbd2_log_start_commit shouldn't dereference transaction->t_tid,
> right?
I think it should be ok because we're holding j_state_lock(), so the
transaction can't disappear until we release the j_state_lock.
- Ted
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