diff mbox series

[Concept,18/21] ext4l: Exclude transaction commits from read-only builds

Message ID 20260108185149.1995917-19-sjg@u-boot.org
State New
Headers
Series ext4l: Add Kconfig options to reduce binary size (part P) |

Commit Message

Simon Glass Jan. 8, 2026, 6:51 p.m. UTC 
  From: Simon Glass <simon.glass@canonical.com>

Add IS_ENABLED(CONFIG_EXT4_WRITE) guards to jbd2 journal code to exclude
write-only functions from read-only ext4l builds.

The kjournald2 thread and jbd2_journal_commit_transaction() are only
needed when writing to the journal. For read-only builds, skip thread
creation and checkpoint/commit operations during journal destroy.

This saves approximately 4K on Thumb2 builds.

Co-developed-by: Claude Opus 4.5 <noreply@anthropic.com>
Signed-off-by: Simon Glass <simon.glass@canonical.com>
---

 fs/jbd2/journal.c | 13 +++++++++++--
 1 file changed, 11 insertions(+), 2 deletions(-)
diff mbox series

Patch

diff --git a/fs/jbd2/journal.c b/fs/jbd2/journal.c
index f6478c6ca94..0d38f00e555 100644
--- a/fs/jbd2/journal.c
+++ b/fs/jbd2/journal.c
@@ -232,6 +232,14 @@  static int jbd2_journal_start_thread(journal_t *journal)
 {
 	struct task_struct *t;
 
+	/*
+	 * The journal thread handles asynchronous commits. For read-only
+	 * builds, we don't need it - commits happen synchronously in
+	 * jbd2_journal_stop() when write support is enabled.
+	 */
+	if (!IS_ENABLED(CONFIG_EXT4_WRITE))
+		return 0;
+
 	t = kthread_run(kjournald2, journal, "jbd2/%s",
 			journal->j_devname);
 	if (IS_ERR(t))
@@ -2117,14 +2125,15 @@  int jbd2_journal_destroy(journal_t *journal)
 	journal_kill_thread(journal);
 
 	/* Force a final log commit */
-	if (journal->j_running_transaction)
+	if (IS_ENABLED(CONFIG_EXT4_WRITE) && journal->j_running_transaction)
 		jbd2_journal_commit_transaction(journal);
 
 	/* Force any old transactions to disk */
 
 	/* Totally anal locking here... */
 	spin_lock(&journal->j_list_lock);
-	while (journal->j_checkpoint_transactions != NULL) {
+	while (IS_ENABLED(CONFIG_EXT4_WRITE) &&
+	       journal->j_checkpoint_transactions != NULL) {
 		spin_unlock(&journal->j_list_lock);
 		mutex_lock_io(&journal->j_checkpoint_mutex);
 		err = jbd2_log_do_checkpoint(journal);