On Mon, Jun 10, 2013 at 03:32:01PM -0400, Paul Gortmaker wrote:
>
> What is interesting here, is that we call log_wait_commit, from
> within wait_for_space, but we are still holding the checkpoint_mutex
> as it surrounds mostly the whole of wait_for_space. And then, as we
> are waiting, journal_commit_transaction can run, and if the JBD2_FLUSHED
> bit is set, then we will also try to take the same checkpoint_mutex.
> } else if (tid) {
> + /*
> + * jbd2_journal_commit_transaction() may want
> + * to take the checkpoint_mutex if JBD2_FLUSHED
> + * is set. So we need to temporarily drop it.
> + */
> + mutex_unlock(&journal->j_checkpoint_mutex);
> jbd2_log_wait_commit(journal, tid);
> + mutex_lock(&journal->j_checkpoint_mutex);
> } else {
> printk(KERN_ERR "%s: needed %d blocks and "
> "only had %d space available\n",
After we execute the code in the else cause, we drop through to just
before the bottom of the while loop, where we see:
mutex_unlock(&journal->j_checkpoint_mutex);
}
So it would be better to change things like this instead, so we don't
end up grabbing and releasing the j_checkpoint_mutex unnecessarily:
} else if (tid) {
+ /*
+ * jbd2_journal_commit_transaction() may want
+ * to take the checkpoint_mutex if JBD2_FLUSHED
+ * is set. So we need to temporarily drop it.
+ */
+ mutex_unlock(&journal->j_checkpoint_mutex);
jbd2_log_wait_commit(journal, tid);
+ write_lock(&journal->j_state_lock);
+ continue;
} else {
printk(KERN_ERR "%s: needed %d blocks and "
"only had %d space available\n",
Could you try respinning the patch like this and testing the result?
Thanks,
- Ted
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