On Tue 30-07-24 19:33:33, Kemeng Shi wrote:
> It's more intuitive to use jh_in->b_frozen_data directly instead of
> done_copy_out variable. Simply remove unneeded done_copy_out variable
> and use b_frozen_data instead.
>
> Signed-off-by: Kemeng Shi <shikemeng@xxxxxxxxxxxxxxx>
> @@ -357,17 +355,15 @@ int jbd2_journal_write_metadata_buffer(transaction_t *transaction,
> new_folio = bh_in->b_folio;
> new_offset = offset_in_folio(new_folio, bh_in->b_data);
> mapped_data = kmap_local_folio(new_folio, new_offset);
> - }
> -
> - /*
> - * Fire data frozen trigger if data already wasn't frozen. Do this
> - * before checking for escaping, as the trigger may modify the magic
> - * offset. If a copy-out happens afterwards, it will have the correct
> - * data in the buffer.
> - */
> - if (!done_copy_out)
> + /*
> + * Fire data frozen trigger if data already wasn't frozen. Do
> + * this before checking for escaping, as the trigger may modify
> + * the magic offset. If a copy-out happens afterwards, it will
> + * have the correct data in the buffer.
> + */
> jbd2_buffer_frozen_trigger(jh_in, mapped_data,
> jh_in->b_triggers);
> + }
I like how you've got rid of the conditional. But I'd go further and also
move the escaping check and thus unmap & possible frozen buffer creation
into the branch. Like:
do_escape = jbd2_data_needs_escaping(mapped_data);
- create this trivial helper
kunmap_local(mapped_data);
if (do_escape) {
handle b_frozen_data creation
}
Honza
>
> /*
> * Check for escaping
> @@ -380,7 +376,7 @@ int jbd2_journal_write_metadata_buffer(transaction_t *transaction,
> /*
> * Do we need to do a data copy?
> */
> - if (do_escape && !done_copy_out) {
> + if (do_escape && !jh_in->b_frozen_data) {
> char *tmp;
>
> spin_unlock(&jh_in->b_state_lock);
> @@ -408,7 +404,6 @@ int jbd2_journal_write_metadata_buffer(transaction_t *transaction,
> copy_done:
> new_folio = virt_to_folio(jh_in->b_frozen_data);
> new_offset = offset_in_folio(new_folio, jh_in->b_frozen_data);
> - done_copy_out = 1;
> }
>
> /*
> --
> 2.30.0
>
--
Jan Kara <jack@xxxxxxxx>
SUSE Labs, CR
