}
 
        /* That test should have eliminated the following case: */
-       J_ASSERT_JH(jh, jh->b_frozen_data == 0);
+       J_ASSERT_JH(jh, jh->b_frozen_data == NULL);
 
        JBUFFER_TRACE(jh, "file as BJ_Metadata");
        spin_lock(&journal->j_list_lock);
 
        J_ASSERT_JH(jh, jh->b_jlist < BJ_Types);
        if (jh->b_jlist != BJ_None)
-               J_ASSERT_JH(jh, transaction != 0);
+               J_ASSERT_JH(jh, transaction != NULL);
 
        switch (jh->b_jlist) {
        case BJ_None:
        if (buffer_locked(bh) || buffer_dirty(bh))
                goto out;
 
-       if (jh->b_next_transaction != 0)
+       if (jh->b_next_transaction != NULL)
                goto out;
 
        spin_lock(&journal->j_list_lock);
-       if (jh->b_transaction != 0 && jh->b_cp_transaction == 0) {
+       if (jh->b_transaction != NULL && jh->b_cp_transaction == NULL) {
                if (jh->b_jlist == BJ_SyncData || jh->b_jlist == BJ_Locked) {
                        /* A written-back ordered data buffer */
                        JBUFFER_TRACE(jh, "release data");
                        jbd2_journal_remove_journal_head(bh);
                        __brelse(bh);
                }
-       } else if (jh->b_cp_transaction != 0 && jh->b_transaction == 0) {
+       } else if (jh->b_cp_transaction != NULL && jh->b_transaction == NULL) {
                /* written-back checkpointed metadata buffer */
                if (jh->b_jlist == BJ_None) {
                        JBUFFER_TRACE(jh, "remove from checkpoint list");
 
        J_ASSERT_JH(jh, jh->b_jlist < BJ_Types);
        J_ASSERT_JH(jh, jh->b_transaction == transaction ||
-                               jh->b_transaction == 0);
+                               jh->b_transaction == NULL);
 
        if (jh->b_transaction && jh->b_jlist == jlist)
                return;