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, 23 insertions, 0 deletions

diff --git a/qapi/block.json b/qapi/block.json
index c694524002..ca807f176a 100644
--- a/qapi/block.json
+++ b/qapi/block.json
@@ -269,6 +269,29 @@
   'data': {'name': 'str', '*mode': 'NbdServerRemoveMode'} }
 
 ##
+# @x-nbd-server-add-bitmap:
+#
+# Expose a dirty bitmap associated with the selected export. The bitmap search
+# starts at the device attached to the export, and includes all backing files.
+# The exported bitmap is then locked until the NBD export is removed.
+#
+# @name: Export name.
+#
+# @bitmap: Bitmap name to search for.
+#
+# @bitmap-export-name: How the bitmap will be seen by nbd clients
+#                      (default @bitmap)
+#
+# Note: the client must use NBD_OPT_SET_META_CONTEXT with a query of
+# "qemu:dirty-bitmap:NAME" (where NAME matches @bitmap-export-name) to access
+# the exposed bitmap.
+#
+# Since: 3.0
+##
+  { 'command': 'x-nbd-server-add-bitmap',
+    'data': {'name': 'str', 'bitmap': 'str', '*bitmap-export-name': 'str'} }
+
+##
 # @nbd-server-stop:
 #
 # Stop QEMU's embedded NBD server, and unregister all devices previously