+
+int llog_is_empty(const struct lu_env *env, struct llog_ctxt *ctxt,
+ char *name)
+{
+ struct llog_handle *llh;
+ int rc = 0;
+
+ rc = llog_open(env, ctxt, &llh, NULL, name, LLOG_OPEN_EXISTS);
+ if (rc < 0) {
+ if (likely(rc == -ENOENT))
+ rc = 0;
+ GOTO(out, rc);
+ }
+
+ rc = llog_init_handle(env, llh, LLOG_F_IS_PLAIN, NULL);
+ if (rc)
+ GOTO(out_close, rc);
+ rc = llog_get_size(llh);
+
+out_close:
+ llog_close(env, llh);
+out:
+ /* header is record 1 */
+ return (rc <= 1);
+}
+EXPORT_SYMBOL(llog_is_empty);
+
+int llog_copy_handler(const struct lu_env *env, struct llog_handle *llh,
+ struct llog_rec_hdr *rec, void *data)
+{
+ struct llog_handle *copy_llh = data;
+
+ /* Append all records */
+ return llog_write(env, copy_llh, rec, NULL, 0, NULL, -1);
+}
+EXPORT_SYMBOL(llog_copy_handler);
+
+/* backup plain llog */
+int llog_backup(const struct lu_env *env, struct obd_device *obd,
+ struct llog_ctxt *ctxt, struct llog_ctxt *bctxt,
+ char *name, char *backup)
+{
+ struct llog_handle *llh, *bllh;
+ int rc;
+
+ ENTRY;
+
+ /* open original log */
+ rc = llog_open(env, ctxt, &llh, NULL, name, LLOG_OPEN_EXISTS);
+ if (rc < 0) {
+ /* the -ENOENT case is also reported to the caller
+ * but silently so it should handle that if needed.
+ */
+ if (rc != -ENOENT)
+ CERROR("%s: failed to open log %s: rc = %d\n",
+ obd->obd_name, name, rc);
+ RETURN(rc);
+ }
+
+ rc = llog_init_handle(env, llh, LLOG_F_IS_PLAIN, NULL);
+ if (rc)
+ GOTO(out_close, rc);
+
+ /* Make sure there's no old backup log */
+ rc = llog_erase(env, bctxt, NULL, backup);
+ if (rc < 0 && rc != -ENOENT)
+ GOTO(out_close, rc);
+
+ /* open backup log */
+ rc = llog_open_create(env, bctxt, &bllh, NULL, backup);
+ if (rc) {
+ CERROR("%s: failed to open backup logfile %s: rc = %d\n",
+ obd->obd_name, backup, rc);
+ GOTO(out_close, rc);
+ }
+
+ /* check that backup llog is not the same object as original one */
+ if (llh->lgh_obj == bllh->lgh_obj) {
+ CERROR("%s: backup llog %s to itself (%s), objects %p/%p\n",
+ obd->obd_name, name, backup, llh->lgh_obj,
+ bllh->lgh_obj);
+ GOTO(out_backup, rc = -EEXIST);
+ }
+
+ rc = llog_init_handle(env, bllh, LLOG_F_IS_PLAIN, NULL);
+ if (rc)
+ GOTO(out_backup, rc);
+
+ /* Copy log record by record */
+ rc = llog_process_or_fork(env, llh, llog_copy_handler, (void *)bllh,
+ NULL, false);
+ if (rc)
+ CERROR("%s: failed to backup log %s: rc = %d\n",
+ obd->obd_name, name, rc);
+out_backup:
+ llog_close(env, bllh);
+out_close:
+ llog_close(env, llh);
+ RETURN(rc);
+}
+EXPORT_SYMBOL(llog_backup);