migration: introduce icount field for snapshots

Saving icount as a parameters of the snapshot allows navigation between
them in the execution replay scenario.
This information can be used for finding a specific snapshot for proceeding
the recorded execution to the specific moment of the time.
E.g., 'reverse step' action (introduced in one of the following patches)
needs to load the nearest snapshot which is prior to the current moment
of time.
This patch also updates snapshot test which verifies qemu monitor output.

Signed-off-by: Pavel Dovgalyuk <Pavel.Dovgalyuk@ispras.ru>
Acked-by: Markus Armbruster <armbru@redhat.com>
Acked-by: Kevin Wolf <kwolf@redhat.com>

--

v4 changes:
 - squashed format update with test output update
v7 changes:
 - introduced the spaces between the fields in snapshot info output
 - updated the test to match new field widths
Message-Id: <160174518865.12451.14327573383978752463.stgit@pasha-ThinkPad-X280>

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

1 files changed, 2 insertions, 2 deletions

diff --git a/tests/qemu-iotests/261 b/tests/qemu-iotests/261
index 848ffa760d..847b4c6a37 100755
--- a/tests/qemu-iotests/261
+++ b/tests/qemu-iotests/261
@@ -392,7 +392,7 @@ _check_test_img -r all
 
 echo
 echo "$((sn_count - 1)) snapshots should remain:"
-echo "  qemu-img info reports $(_img_info | grep -c '^ \{34\}') snapshots"
+echo "  qemu-img info reports $(_img_info | grep -c '^ \{32\}') snapshots"
 echo "  Image header reports $(peek_file_be "$TEST_IMG" 60 4) snapshots"
 
 echo
@@ -519,7 +519,7 @@ _check_test_img -r all
 
 echo
 echo '65536 snapshots should remain:'
-echo "  qemu-img info reports $(_img_info | grep -c '^ \{34\}') snapshots"
+echo "  qemu-img info reports $(_img_info | grep -c '^ \{32\}') snapshots"
 echo "  Image header reports $(peek_file_be "$TEST_IMG" 60 4) snapshots"
 
 # success, all done