diff --git a/include/zrepl_mgmt.h b/include/zrepl_mgmt.h
index 1901a6abf714..2570ea3cd761 100644
--- a/include/zrepl_mgmt.h
+++ b/include/zrepl_mgmt.h
@@ -141,6 +141,7 @@ typedef struct zvol_io_cmd_s {
 	zvol_io_hdr_t 	hdr;
 	void		*zv;
 	void		*buf;
+	uint64_t	buf_len;
 	metadata_desc_t	*metadata_desc;
 	int		conn;
 } zvol_io_cmd_t;
diff --git a/lib/libzrepl/data_conn.c b/lib/libzrepl/data_conn.c
index 81da8774bb01..d47943d8b755 100644
--- a/lib/libzrepl/data_conn.c
+++ b/lib/libzrepl/data_conn.c
@@ -62,6 +62,7 @@ zio_cmd_alloc(zvol_io_hdr_t *hdr, int fd)
 	    (hdr->opcode == ZVOL_OPCODE_WRITE) ||
 	    (hdr->opcode == ZVOL_OPCODE_OPEN)) {
 		zio_cmd->buf = kmem_zalloc(sizeof (char) * hdr->len, KM_SLEEP);
+		zio_cmd->buf_len = hdr->len;
 	}
 
 	zio_cmd->conn = fd;
@@ -81,7 +82,7 @@ zio_cmd_free(zvol_io_cmd_t **cmd)
 		case ZVOL_OPCODE_WRITE:
 		case ZVOL_OPCODE_OPEN:
 			if (zio_cmd->buf != NULL) {
-				kmem_free(zio_cmd->buf, zio_cmd->hdr.len);
+				kmem_free(zio_cmd->buf, zio_cmd->buf_len);
 			}
 			break;
 
@@ -260,11 +261,13 @@ uzfs_zvol_worker(void *arg)
 	read_metadata = hdr->flags & ZVOL_OP_FLAG_READ_METADATA;
 
 	/*
-	 * Why to delay offline activity ? anyway
-	 * we are not going to ACK these IOs
+	 * For rebuild case, do not free zio_cmd
 	 */
 	if (zinfo->state == ZVOL_INFO_STATE_OFFLINE) {
-		zio_cmd_free(&zio_cmd);
+		hdr->status = ZVOL_OP_STATUS_FAILED;
+		hdr->len = 0;
+		if (!(rebuild_cmd_req && (hdr->opcode == ZVOL_OPCODE_WRITE)))
+			zio_cmd_free(&zio_cmd);
 		goto drop_refcount;
 	}