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[PATCH 1/3] nbd: Preparation for NBD_INFO_INIT_STATE
From: |
Eric Blake |
Subject: |
[PATCH 1/3] nbd: Preparation for NBD_INFO_INIT_STATE |
Date: |
Mon, 10 Feb 2020 15:41:07 -0600 |
Declare the constants being proposed for an NBD extension, which will
let qemu advertise/learn if an image began life with all zeroes.
Signed-off-by: Eric Blake <address@hidden>
---
docs/interop/nbd.txt | 1 +
include/block/nbd.h | 9 +++++++++
nbd/common.c | 2 ++
3 files changed, 12 insertions(+)
diff --git a/docs/interop/nbd.txt b/docs/interop/nbd.txt
index 45118809618e..35ba85367153 100644
--- a/docs/interop/nbd.txt
+++ b/docs/interop/nbd.txt
@@ -55,3 +55,4 @@ the operation of that feature.
NBD_CMD_BLOCK_STATUS for "qemu:dirty-bitmap:", NBD_CMD_CACHE
* 4.2: NBD_FLAG_CAN_MULTI_CONN for sharable read-only exports,
NBD_CMD_FLAG_FAST_ZERO
+* 5.0: NBD_INFO_INIT_STATE
diff --git a/include/block/nbd.h b/include/block/nbd.h
index 7f46932d80f1..0de020904a37 100644
--- a/include/block/nbd.h
+++ b/include/block/nbd.h
@@ -200,6 +200,15 @@ enum {
#define NBD_INFO_NAME 1
#define NBD_INFO_DESCRIPTION 2
#define NBD_INFO_BLOCK_SIZE 3
+#define NBD_INFO_INIT_STATE 4
+
+/* Initial state bits, when replying to NBD_INFO_INIT_STATE */
+enum {
+ NBD_INIT_SPARSE_BIT = 0,
+ NBD_INIT_ZERO_BIT = 1,
+};
+#define NBD_INIT_SPARSE (1 << NBD_INIT_SPARSE_BIT)
+#define NBD_INIT_ZERO (1 << NBD_INIT_ZERO_BIT)
/* Request flags, sent from client to server during transmission phase */
#define NBD_CMD_FLAG_FUA (1 << 0) /* 'force unit access' during write */
diff --git a/nbd/common.c b/nbd/common.c
index ddfe7d118371..3e24feb0d502 100644
--- a/nbd/common.c
+++ b/nbd/common.c
@@ -129,6 +129,8 @@ const char *nbd_info_lookup(uint16_t info)
return "description";
case NBD_INFO_BLOCK_SIZE:
return "block size";
+ case NBD_INFO_INIT_STATE:
+ return "init state";
default:
return "<unknown>";
}
--
2.24.1