Merge remote-tracking branch 'remotes/ericb/tags/pull-nbd-2018-06-20-v2' into staging

nbd patches for 2018-06-20

Add experimental x-nbd-server-add-bitmap to expose a disabled
bitmap over NBD, in preparation for a pull model incremental
backup scheme. Also fix a corner case protocol issue with
NBD_CMD_BLOCK_STATUS, and add new NBD_CMD_CACHE.

- Eric Blake: tests: Simplify .gitignore
- Eric Blake: nbd/server: Reject 0-length block status request
- Vladimir Sementsov-Ogievskiy: 0/6 NBD export bitmaps
- Vladimir Sementsov-Ogievskiy: nbd/server: introduce NBD_CMD_CACHE

# gpg: Signature made Thu 21 Jun 2018 15:53:55 BST
# gpg:                using RSA key A7A16B4A2527436A
# gpg: Good signature from "Eric Blake <eblake@redhat.com>"
# gpg:                 aka "Eric Blake (Free Software Programmer) <ebb9@byu.net>"
# gpg:                 aka "[jpeg image of size 6874]"
# Primary key fingerprint: 71C2 CC22 B1C4 6029 27D2  F3AA A7A1 6B4A 2527 436A

* remotes/ericb/tags/pull-nbd-2018-06-20-v2:
  nbd/server: introduce NBD_CMD_CACHE
  docs/interop: add nbd.txt
  qapi: new qmp command nbd-server-add-bitmap
  nbd/server: implement dirty bitmap export
  nbd/server: add nbd_meta_empty_or_pattern helper
  nbd/server: refactor NBDExportMetaContexts
  nbd/server: fix trace
  nbd/server: Reject 0-length block status request
  tests: Simplify .gitignore

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

1 files changed, 8 insertions, 3 deletions

diff --git a/include/block/nbd.h b/include/block/nbd.h
index fcdcd54..daaeae6 100644
--- a/include/block/nbd.h
+++ b/include/block/nbd.h
@@ -135,6 +135,7 @@ typedef struct NBDExtent {
 #define NBD_FLAG_SEND_TRIM         (1 << 5) /* Send TRIM (discard) */
 #define NBD_FLAG_SEND_WRITE_ZEROES (1 << 6) /* Send WRITE_ZEROES */
 #define NBD_FLAG_SEND_DF           (1 << 7) /* Send DF (Do not Fragment) */
+#define NBD_FLAG_SEND_CACHE        (1 << 8) /* Send CACHE (prefetch) */
 
 /* New-style handshake (global) flags, sent from server to client, and
    control what will happen during handshake phase. */
@@ -195,7 +196,7 @@ enum {
     NBD_CMD_DISC = 2,
     NBD_CMD_FLUSH = 3,
     NBD_CMD_TRIM = 4,
-    /* 5 reserved for failed experiment NBD_CMD_CACHE */
+    NBD_CMD_CACHE = 5,
     NBD_CMD_WRITE_ZEROES = 6,
     NBD_CMD_BLOCK_STATUS = 7,
 };
@@ -229,11 +230,13 @@ enum {
 #define NBD_REPLY_TYPE_ERROR         NBD_REPLY_ERR(1)
 #define NBD_REPLY_TYPE_ERROR_OFFSET  NBD_REPLY_ERR(2)
 
-/* Flags for extents (NBDExtent.flags) of NBD_REPLY_TYPE_BLOCK_STATUS,
- * for base:allocation meta context */
+/* Extent flags for base:allocation in NBD_REPLY_TYPE_BLOCK_STATUS */
 #define NBD_STATE_HOLE (1 << 0)
 #define NBD_STATE_ZERO (1 << 1)
 
+/* Extent flags for qemu:dirty-bitmap in NBD_REPLY_TYPE_BLOCK_STATUS */
+#define NBD_STATE_DIRTY (1 << 0)
+
 static inline bool nbd_reply_type_is_error(int type)
 {
     return type & (1 << 15);
@@ -315,6 +318,8 @@ void nbd_client_put(NBDClient *client);
 void nbd_server_start(SocketAddress *addr, const char *tls_creds,
                       Error **errp);
 
+void nbd_export_bitmap(NBDExport *exp, const char *bitmap,
+                       const char *bitmap_export_name, Error **errp);
 
 /* nbd_read
  * Reads @size bytes from @ioc. Returns 0 on success.