jbd2: move escape handle to futher improve jbd2_journal_write_metadata_buffer

Move escape handle to futher improve code readability and remove some
repeat check.

Signed-off-by: Kemeng Shi <shikemeng@huaweicloud.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Zhang Yi <yi.zhang@huawei.com>
Link: https://patch.msgid.link/20240801013815.2393869-7-shikemeng@huaweicloud.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

diff --git a/fs/jbd2/journal.c b/fs/jbd2/journal.c
index 225a9a12333559c6ceaf137e80b05eb4ab704151..2e61f001fc0363e721932d99fd7c2a0c2b58a95c 100644 (file)
--- 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;