on 8/7/2024 3:41 PM, wangjianjian (C) wrote:
> On 2024/7/31 17:29, Kemeng Shi wrote:
>> Move escape handle to futher improve code readability and remove some
>> repeat check.
> Should subject prefix "ext4" be "jbd2" ?
Hello, I have updated this in v4 series. Thanks!
Kemeng
>
>>
>> Signed-off-by: Kemeng Shi <shikemeng@xxxxxxxxxxxxxxx>
>> ---
>> fs/jbd2/journal.c | 49 +++++++++++++++++++++++------------------------
>> 1 file changed, 24 insertions(+), 25 deletions(-)
>>
>> diff --git a/fs/jbd2/journal.c b/fs/jbd2/journal.c
>> index f17d05bc61df..85273fb1accb 100644
>> --- a/fs/jbd2/journal.c
>> +++ b/fs/jbd2/journal.c
>> @@ -281,6 +281,16 @@ static void journal_kill_thread(journal_t *journal)
>> write_unlock(&journal->j_state_lock);
>> }
>> +static inline bool jbd2_data_needs_escaping(char *data)
>> +{
>> + return *((__be32 *)data) == cpu_to_be32(JBD2_MAGIC_NUMBER);
>> +}
>> +
>> +static inline void jbd2_data_do_escape(char *data)
>> +{
>> + *((unsigned int *)data) = 0;
>> +}
>> +
>> /*
>> * jbd2_journal_write_metadata_buffer: write a metadata buffer to the journal.
>> *
>> @@ -319,7 +329,6 @@ int jbd2_journal_write_metadata_buffer(transaction_t *transaction,
>> sector_t blocknr)
>> {
>> int do_escape = 0;
>> - char *mapped_data;
>> struct buffer_head *new_bh;
>> struct folio *new_folio;
>> unsigned int new_offset;
>> @@ -350,8 +359,13 @@ int jbd2_journal_write_metadata_buffer(transaction_t *transaction,
>> if (jh_in->b_frozen_data) {
>> new_folio = virt_to_folio(jh_in->b_frozen_data);
>> new_offset = offset_in_folio(new_folio, jh_in->b_frozen_data);
>> - mapped_data = jh_in->b_frozen_data;
>> + do_escape = jbd2_data_needs_escaping(jh_in->b_frozen_data);
>> + if (do_escape)
>> + jbd2_data_do_escape(jh_in->b_frozen_data);
>> } else {
>> + char *tmp;
>> + char *mapped_data;
>> +
>> 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);
>> @@ -363,21 +377,13 @@ int jbd2_journal_write_metadata_buffer(transaction_t *transaction,
>> */
>> jbd2_buffer_frozen_trigger(jh_in, mapped_data,
>> jh_in->b_triggers);
>> - }
>> -
>> - /*
>> - * Check for escaping
>> - */
>> - if (*((__be32 *)mapped_data) == cpu_to_be32(JBD2_MAGIC_NUMBER))
>> - do_escape = 1;
>> - if (!jh_in->b_frozen_data)
>> + do_escape = jbd2_data_needs_escaping(mapped_data);
>> kunmap_local(mapped_data);
>> -
>> - /*
>> - * Do we need to do a data copy?
>> - */
>> - if (do_escape && !jh_in->b_frozen_data) {
>> - char *tmp;
>> + /*
>> + * Do we need to do a data copy?
>> + */
>> + if (!do_escape)
>> + goto escape_done;
>> spin_unlock(&jh_in->b_state_lock);
>> tmp = jbd2_alloc(bh_in->b_size, GFP_NOFS);
>> @@ -404,17 +410,10 @@ 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);
>> + jbd2_data_do_escape(jh_in->b_frozen_data);
>> }
>> - /*
>> - * Did we need to do an escaping? Now we've done all the
>> - * copying, we can finally do so.
>> - * b_frozen_data is from jbd2_alloc() which always provides an
>> - * address from the direct kernels mapping.
>> - */
>> - if (do_escape)
>> - *((unsigned int *)jh_in->b_frozen_data) = 0;
>> -
>> +escape_done:
>> folio_set_bh(new_bh, new_folio, new_offset);
>> new_bh->b_size = bh_in->b_size;
>> new_bh->b_bdev = journal->j_dev;
