-#define _OST_MAXREQSIZE_SUM (sizeof(struct lustre_msg) + sizeof(struct obdo) + \
- sizeof(struct obd_ioobj) + DT_MAX_BRW_PAGES * \
- sizeof(struct niobuf_remote))
-#define OST_MAXREQSIZE (((_OST_MAXREQSIZE_SUM - 1) | (1024 - 1)) + 1)
+#define _OST_MAXREQSIZE_SUM (sizeof(struct lustre_msg) + \
+ sizeof(struct ptlrpc_body) + \
+ sizeof(struct obdo) + \
+ sizeof(struct obd_ioobj) + \
+ sizeof(struct niobuf_remote) * DT_MAX_BRW_PAGES)
+/**
+ * FIEMAP request can be 4K+ for now
+ */
+#define OST_MAXREQSIZE (5 * 1024)
+#define OST_IO_MAXREQSIZE max_t(int, OST_MAXREQSIZE, \
+ (((_OST_MAXREQSIZE_SUM - 1) | (1024 - 1)) + 1))