jbd2: use bh_in instead of jh2bh(jh_in) to simplify code

We save jh2bh(jh_in) to bh_in, so use bh_in directly instead of
jh2bh(jh_in) to simplify the code.

Signed-off-by: Kemeng Shi <[email protected]>
Reviewed-by: Zhang Yi <[email protected]>
Reviewed-by: Jan Kara <[email protected]>
Link: https://patch.msgid.link/[email protected]
Signed-off-by: Theodore Ts'o <[email protected]>

Author: Kemeng Shi

fs/jbd2/journal.c

@@ -360,8 +360,8 @@ int jbd2_journal_write_metadata_buffer(transaction_t *transaction,
 		new_folio = virt_to_folio(jh_in->b_frozen_data);
 		new_offset = offset_in_folio(new_folio, jh_in->b_frozen_data);
 	} else {
-		new_folio = jh2bh(jh_in)->b_folio;
-		new_offset = offset_in_folio(new_folio, jh2bh(jh_in)->b_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);