Flush if we can not get logbuffer memory

src/fellow_log.c

@@ -3289,14 +3289,23 @@ logbuffer_getblk(struct fellow_fd *ffd,
 {
 	struct fellow_disk_log_block *blk;
 	struct fellow_alloc_log_block ablk[1];
+	unsigned canflush, wait;
 
 	if (new == GET_USED &&
 	    lbuf->active.block &&
 	    lbuf->active.block->nentries < FELLOW_DISK_LOG_BLOCK_ENTRIES)
 		return (lbuf->active.block);
 
-	blk = fellow_logblk_new(lbuf, 1,
-	    ffd->tune->hash_log, lbuf->id);
+	canflush =
+	    logbuffer_can(lbuf, LBUF_CAN_FLUSH) ||
+	    logbuffer_can(lbuf, LBUF_CAN_LOGREG);
+
+	for (blk = NULL, wait = 0; blk == NULL && wait < 2; wait++) {
+		blk = fellow_logblk_new(lbuf, wait,
+		    ffd->tune->hash_log, lbuf->id);
+		if (blk == NULL && canflush)
+			logbuffer_flush(ffd, lbuf, 0, LBUF_ALL);
+	}
 	XXXAN(blk);
 
 	ablk->block = blk;