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" ?
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;
--
Regards
