Re: [PATCH] Change ll_rw_block() calls in JBD

[Zoltan Menyhart]

Getting better :-)

> +		was_dirty = buffer_dirty(bh);

Why do not we use "buffer_jbddirty()"?

> +		if (was_dirty && test_set_buffer_locked(bh)) {
> +			BUFFER_TRACE(bh, "needs blocking lock");
> +			get_bh(bh);

Why do you need a "get_bh(bh)"?
"bh" is attached to "jh".
Can it go away while waiting for the buffer lock?
("jh" in on "t_sync_datalist", it cannot go away.)

> +			spin_unlock(&journal->j_list_lock);
> +			lock_buffer(bh);
> +			spin_lock(&journal->j_list_lock);
> +			/* Someone already cleaned up the buffer? Restart. */
> +			if (!buffer_jbd(bh) || jh->b_jlist != BJ_SyncData) {

Who (else) can take away the journal head, remove our "jh" from the
synch. data list?

> +		else {
> +			BUFFER_TRACE(bh, "needs writeout, submitting");
>  			__journal_temp_unlink_buffer(jh);
>  			__journal_file_buffer(jh, commit_transaction,
>  						BJ_Locked);

A simple "__journal_file_buffer(...)" could be enough as it includes:

	if (jh->b_transaction)
		__journal_temp_unlink_buffer(jh);


Would not it be more easy to read like this?

               if ((!was_dirty && buffer_locked(bh))
                   || (was_dirty && test_clear_buffer_dirty(bh))) {
                       BUFFER_TRACE(bh, "needs writeout, submitting");
                       __journal_temp_unlink_buffer(jh);
                       __journal_file_buffer(jh, commit_transaction,
                                               BJ_Locked);
                       jbd_unlock_bh_state(bh);
                       if (was_dirty) {
                               get_bh(bh);
                               bh->b_end_io = end_buffer_write_sync;
                               submit_bh(WRITE, bh);
                       }
               }
               else {

                       BUFFER_TRACE(bh, "writeout complete: unfile");
                       __journal_unfile_buffer(jh);
                       jbd_unlock_bh_state(bh);
                       journal_remove_journal_head(bh);
                       if (was_dirty)
                               unlock_buffer(bh);
                       put_bh(bh);
               }


As synch. data handling is a compact stuff, cannot it be moved out from
"journal_commit_transaction()" as e.g. "journal_write_revoke_records()"?
(Just for a better readability...)

Thanks,

Zoltan







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