on 5/7/2024 7:51 PM, Zhang Yi wrote:
> On 2024/5/6 22:17, Kemeng Shi wrote:
>> The done_copy_out info from jbd2_journal_write_metadata_buffer is not
>> used. Simply remove it.
>>
>> Signed-off-by: Kemeng Shi <shikemeng@xxxxxxxxxxxxxxx>
>> ---
>> fs/jbd2/journal.c | 3 +--
>> 1 file changed, 1 insertion(+), 2 deletions(-)
>>
>> diff --git a/fs/jbd2/journal.c b/fs/jbd2/journal.c
>> index 207b24e12ce9..068031f35aea 100644
>> --- a/fs/jbd2/journal.c
>> +++ b/fs/jbd2/journal.c
>> @@ -320,7 +320,6 @@ static void journal_kill_thread(journal_t *journal)
>> *
>> * On success:
>> * Bit 0 set == escape performed on the data
>> - * Bit 1 set == buffer copy-out performed (kfree the data after IO)
>> */
>>
>> int jbd2_journal_write_metadata_buffer(transaction_t *transaction,
>> @@ -455,7 +454,7 @@ int jbd2_journal_write_metadata_buffer(transaction_t *transaction,
>> set_buffer_shadow(bh_in);
>> spin_unlock(&jh_in->b_state_lock);
>>
>> - return do_escape | (done_copy_out << 1);
>> + return do_escape;
>> }
>>
>
> I checked the history, it seems that this bit has not been used since
> the very beginning when the jbd code was merged in, I suppose we could
> drop it. Since there is only one flag that is still in use, why not just
> drop the flag and pass out do_escape through an output parameter, or
> directly pass tag_flag, after that we could also drop the weird
> "if (flags & 1)" check in jbd2_journal_commit_transaction()?
Thanks for looking into this. I agree that the "flags & 1" is wired, I
wonder if we could further remove "flags & 1" with following change:
diff --git a/fs/jbd2/commit.c b/fs/jbd2/commit.c
index 5e122586e06e..67077308b56b 100644
--- a/fs/jbd2/commit.c
+++ b/fs/jbd2/commit.c
@@ -353,7 +353,7 @@ void jbd2_journal_commit_transaction(journal_t *journal)
struct buffer_head *descriptor;
struct buffer_head **wbuf = journal->j_wbuf;
int bufs;
- int flags;
+ int escape;
int err;
unsigned long long blocknr;
ktime_t start_time;
@@ -661,10 +661,10 @@ void jbd2_journal_commit_transaction(journal_t *journal)
*/
set_bit(BH_JWrite, &jh2bh(jh)->b_state);
JBUFFER_TRACE(jh, "ph3: write metadata");
- flags = jbd2_journal_write_metadata_buffer(commit_transaction,
+ escape = jbd2_journal_write_metadata_buffer(commit_transaction,
jh, &wbuf[bufs], blocknr);
- if (flags < 0) {
- jbd2_journal_abort(journal, flags);
+ if (escape < 0) {
+ jbd2_journal_abort(journal, escape);
continue;
}
jbd2_file_log_bh(&io_bufs, wbuf[bufs]);
@@ -673,7 +673,7 @@ void jbd2_journal_commit_transaction(journal_t *journal)
buffer */
tag_flag = 0;
- if (flags & 1)
+ if (escape)
tag_flag |= JBD2_FLAG_ESCAPE;
if (!first_tag)
tag_flag |= JBD2_FLAG_SAME_UUID;
diff --git a/fs/jbd2/journal.c b/fs/jbd2/journal.c
index 08c59197c5bd..c8a1eca5caab 100644
--- a/fs/jbd2/journal.c
+++ b/fs/jbd2/journal.c
@@ -309,10 +309,8 @@ static void journal_kill_thread(journal_t *journal)
*
* Return value:
* <0: Error
- * >=0: Finished OK
- *
- * On success:
- * Bit 0 set == escape performed on the data
+ * =0: Finished OK without escape
+ * =1: Finished OK with escape
*/
Look forward to your reply.
Thanks.
Kemeng
>
> Thanks,
> Yi.
>
