on 7/30/2024 9:49 PM, Jan Kara wrote:
> 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
> }
Thanks Jan. It does look better this way, I will do it in next version.
Kemeng.
>
> 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
>>
