[Libguestfs] [nbdkit PATCH 01/10] protocol: Add NBD_INFO_INIT_STATE extension
The NBD protocol is adding an extension to make it possible for
servers to advertise to the client if the export is known to start
life as a sparse file or with all-zero state. Although this extension
is optional, clients can take advantage of it during certain
operations (such as making image copying more efficient by not having
to request a pre-zeroing pass). This patch exposes the constants that
will be used by nbdkit, as well as shared in libnbd for client side
use.
Signed-off-by: Eric Blake <eblake(a)redhat.com>
---
common/protocol/nbd-protocol.h | 13 ++++++++++++-
1 file changed, 12 insertions(+), 1 deletion(-)
diff --git a/common/protocol/nbd-protocol.h b/common/protocol/nbd-protocol.h
index df0b4c6..50531a0 100644
--- a/common/protocol/nbd-protocol.h
+++ b/common/protocol/nbd-protocol.h
@@ -1,5 +1,5 @@
/* nbdkit
- * Copyright (C) 2013-2019 Red Hat Inc.
+ * Copyright (C) 2013-2020 Red Hat Inc.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are
@@ -146,6 +146,7 @@ struct nbd_fixed_new_option_reply {
#define NBD_INFO_NAME 1
#define NBD_INFO_DESCRIPTION 2
#define NBD_INFO_BLOCK_SIZE 3
+#define NBD_INFO_INIT_STATE 4
/* NBD_INFO_EXPORT reply (follows fixed_new_option_reply). */
struct nbd_fixed_new_option_reply_info_export {
@@ -154,6 +155,16 @@ struct nbd_fixed_new_option_reply_info_export {
uint16_t eflags; /* per-export flags */
} NBD_ATTRIBUTE_PACKED;
+/* NBD_INFO_INIT_STATE reply. */
+struct nbd_fixed_new_option_reply_info_init {
+ uint16_t info; /* NBD_INFO_INIT_STATE */
+ uint16_t flags; /* per-export init flags */
+} NBD_ATTRIBUTE_PACKED;
+
+/* Constants for use in reply to NBD_INFO_INIT_STATE. */
+#define NBD_INIT_SPARSE (1 << 0)
+#define NBD_INIT_ZERO (1 << 1)
+
/* NBD_REP_META_CONTEXT reply (follows fixed_new_option_reply). */
struct nbd_fixed_new_option_reply_meta_context {
uint32_t context_id; /* metadata context ID */
--
2.24.1