Merge remote-tracking branch 'remotes/ericb/tags/pull-bitmaps-2020-07-27' into staging

bitmaps patches for 2020-07-27

- Improve handling of various post-copy bitmap migration scenarios. A lost
bitmap should merely mean that the next backup must be full rather than
incremental, rather than abruptly breaking the entire guest migration.
- Associated iotest improvements

# gpg: Signature made Mon 27 Jul 2020 21:46:17 BST
# gpg:                using RSA key 71C2CC22B1C4602927D2F3AAA7A16B4A2527436A
# gpg: Good signature from "Eric Blake <eblake@redhat.com>" [full]
# gpg:                 aka "Eric Blake (Free Software Programmer) <ebb9@byu.net>" [full]
# gpg:                 aka "[jpeg image of size 6874]" [full]
# Primary key fingerprint: 71C2 CC22 B1C4 6029 27D2  F3AA A7A1 6B4A 2527 436A

* remotes/ericb/tags/pull-bitmaps-2020-07-27: (24 commits)
  migration: Fix typos in bitmap migration comments
  iotests: Adjust which migration tests are quick
  qemu-iotests/199: add source-killed case to bitmaps postcopy
  qemu-iotests/199: add early shutdown case to bitmaps postcopy
  qemu-iotests/199: check persistent bitmaps
  qemu-iotests/199: prepare for new test-cases addition
  migration/savevm: don't worry if bitmap migration postcopy failed
  migration/block-dirty-bitmap: cancel migration on shutdown
  migration/block-dirty-bitmap: relax error handling in incoming part
  migration/block-dirty-bitmap: keep bitmap state for all bitmaps
  migration/block-dirty-bitmap: simplify dirty_bitmap_load_complete
  migration/block-dirty-bitmap: rename finish_lock to just lock
  migration/block-dirty-bitmap: refactor state global variables
  migration/block-dirty-bitmap: move mutex init to dirty_bitmap_mig_init
  migration/block-dirty-bitmap: rename dirty_bitmap_mig_cleanup
  migration/block-dirty-bitmap: rename state structure types
  migration/block-dirty-bitmap: fix dirty_bitmap_mig_before_vm_start
  qemu-iotests/199: increase postcopy period
  qemu-iotests/199: change discard patterns
  qemu-iotests/199: improve performance: set bitmap by discard
  ...

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

3 files changed, 204 insertions, 62 deletions

diff --git a/tests/qemu-iotests/199 b/tests/qemu-iotests/199
index 40774eed74..58fad872a1 100755
--- a/tests/qemu-iotests/199
+++ b/tests/qemu-iotests/199
@@ -20,17 +20,76 @@
 
 import os
 import iotests
-import time
 from iotests import qemu_img
 
+debug = False
+
 disk_a = os.path.join(iotests.test_dir, 'disk_a')
 disk_b = os.path.join(iotests.test_dir, 'disk_b')
 size = '256G'
 fifo = os.path.join(iotests.test_dir, 'mig_fifo')
 
-class TestDirtyBitmapPostcopyMigration(iotests.QMPTestCase):
+granularity = 512
+nb_bitmaps = 15
+
+GiB = 1024 * 1024 * 1024
+
+discards1 = (
+    (0, GiB),
+    (2 * GiB + 512 * 5, 512),
+    (3 * GiB + 512 * 5, 512),
+    (100 * GiB, GiB)
+)
+
+discards2 = (
+    (3 * GiB + 512 * 8, 512),
+    (4 * GiB + 512 * 8, 512),
+    (50 * GiB, GiB),
+    (100 * GiB + GiB // 2, GiB)
+)
+
+
+def apply_discards(vm, discards):
+    for d in discards:
+        vm.hmp_qemu_io('drive0', 'discard {} {}'.format(*d))
+
+
+def event_seconds(event):
+    return event['timestamp']['seconds'] + \
+        event['timestamp']['microseconds'] / 1000000.0
+
+
+def event_dist(e1, e2):
+    return event_seconds(e2) - event_seconds(e1)
+
+
+def check_bitmaps(vm, count):
+    result = vm.qmp('query-block')
+
+    if count == 0:
+        assert 'dirty-bitmaps' not in result['return'][0]
+    else:
+        assert len(result['return'][0]['dirty-bitmaps']) == count
 
+
+class TestDirtyBitmapPostcopyMigration(iotests.QMPTestCase):
     def tearDown(self):
+        if debug:
+            self.vm_a_events += self.vm_a.get_qmp_events()
+            self.vm_b_events += self.vm_b.get_qmp_events()
+            for e in self.vm_a_events:
+                e['vm'] = 'SRC'
+            for e in self.vm_b_events:
+                e['vm'] = 'DST'
+            events = (self.vm_a_events + self.vm_b_events)
+            events = [(e['timestamp']['seconds'],
+                       e['timestamp']['microseconds'],
+                       e['vm'],
+                       e['event'],
+                       e.get('data', '')) for e in events]
+            for e in sorted(events):
+                print('{}.{:06} {} {} {}'.format(*e))
+
         self.vm_a.shutdown()
         self.vm_b.shutdown()
         os.remove(disk_a)
@@ -41,51 +100,66 @@ class TestDirtyBitmapPostcopyMigration(iotests.QMPTestCase):
         os.mkfifo(fifo)
         qemu_img('create', '-f', iotests.imgfmt, disk_a, size)
         qemu_img('create', '-f', iotests.imgfmt, disk_b, size)
-        self.vm_a = iotests.VM(path_suffix='a').add_drive(disk_a)
-        self.vm_b = iotests.VM(path_suffix='b').add_drive(disk_b)
+        self.vm_a = iotests.VM(path_suffix='a').add_drive(disk_a,
+                                                          'discard=unmap')
+        self.vm_b = iotests.VM(path_suffix='b').add_drive(disk_b,
+                                                          'discard=unmap')
         self.vm_b.add_incoming("exec: cat '" + fifo + "'")
         self.vm_a.launch()
         self.vm_b.launch()
 
-    def test_postcopy(self):
-        write_size = 0x40000000
-        granularity = 512
-        chunk = 4096
+        # collect received events for debug
+        self.vm_a_events = []
+        self.vm_b_events = []
 
-        result = self.vm_a.qmp('block-dirty-bitmap-add', node='drive0',
-                               name='bitmap', granularity=granularity)
-        self.assert_qmp(result, 'return', {});
+    def start_postcopy(self):
+        """ Run migration until RESUME event on target. Return this event. """
+        for i in range(nb_bitmaps):
+            result = self.vm_a.qmp('block-dirty-bitmap-add', node='drive0',
+                                   name='bitmap{}'.format(i),
+                                   granularity=granularity,
+                                   persistent=True)
+            self.assert_qmp(result, 'return', {})
 
-        s = 0
-        while s < write_size:
-            self.vm_a.hmp_qemu_io('drive0', 'write %d %d' % (s, chunk))
-            s += 0x10000
-        s = 0x8000
-        while s < write_size:
-            self.vm_a.hmp_qemu_io('drive0', 'write %d %d' % (s, chunk))
-            s += 0x10000
+        result = self.vm_a.qmp('x-debug-block-dirty-bitmap-sha256',
+                               node='drive0', name='bitmap0')
+        empty_sha256 = result['return']['sha256']
+
+        apply_discards(self.vm_a, discards1)
 
         result = self.vm_a.qmp('x-debug-block-dirty-bitmap-sha256',
-                               node='drive0', name='bitmap')
-        sha256 = result['return']['sha256']
-
-        result = self.vm_a.qmp('block-dirty-bitmap-clear', node='drive0',
-                               name='bitmap')
-        self.assert_qmp(result, 'return', {});
-        s = 0
-        while s < write_size:
-            self.vm_a.hmp_qemu_io('drive0', 'write %d %d' % (s, chunk))
-            s += 0x10000
-
-        bitmaps_cap = {'capability': 'dirty-bitmaps', 'state': True}
-        events_cap = {'capability': 'events', 'state': True}
-
-        result = self.vm_a.qmp('migrate-set-capabilities',
-                               capabilities=[bitmaps_cap, events_cap])
+                               node='drive0', name='bitmap0')
+        self.discards1_sha256 = result['return']['sha256']
+
+        # Check, that updating the bitmap by discards works
+        assert self.discards1_sha256 != empty_sha256
+
+        # We want to calculate resulting sha256. Do it in bitmap0, so, disable
+        # other bitmaps
+        for i in range(1, nb_bitmaps):
+            result = self.vm_a.qmp('block-dirty-bitmap-disable', node='drive0',
+                                   name='bitmap{}'.format(i))
+            self.assert_qmp(result, 'return', {})
+
+        apply_discards(self.vm_a, discards2)
+
+        result = self.vm_a.qmp('x-debug-block-dirty-bitmap-sha256',
+                               node='drive0', name='bitmap0')
+        self.all_discards_sha256 = result['return']['sha256']
+
+        # Now, enable some bitmaps, to be updated during migration
+        for i in range(2, nb_bitmaps, 2):
+            result = self.vm_a.qmp('block-dirty-bitmap-enable', node='drive0',
+                                   name='bitmap{}'.format(i))
+            self.assert_qmp(result, 'return', {})
+
+        caps = [{'capability': 'dirty-bitmaps', 'state': True},
+                {'capability': 'events', 'state': True}]
+
+        result = self.vm_a.qmp('migrate-set-capabilities', capabilities=caps)
         self.assert_qmp(result, 'return', {})
 
-        result = self.vm_b.qmp('migrate-set-capabilities',
-                               capabilities=[bitmaps_cap])
+        result = self.vm_b.qmp('migrate-set-capabilities', capabilities=caps)
         self.assert_qmp(result, 'return', {})
 
         result = self.vm_a.qmp('migrate', uri='exec:cat>' + fifo)
@@ -94,26 +168,94 @@ class TestDirtyBitmapPostcopyMigration(iotests.QMPTestCase):
         result = self.vm_a.qmp('migrate-start-postcopy')
         self.assert_qmp(result, 'return', {})
 
-        while True:
-            event = self.vm_a.event_wait('MIGRATION')
-            if event['data']['status'] == 'completed':
-                break
+        event_resume = self.vm_b.event_wait('RESUME')
+        self.vm_b_events.append(event_resume)
+        return event_resume
+
+    def test_postcopy_success(self):
+        event_resume = self.start_postcopy()
+
+        # enabled bitmaps should be updated
+        apply_discards(self.vm_b, discards2)
+
+        match = {'data': {'status': 'completed'}}
+        event_complete = self.vm_b.event_wait('MIGRATION', match=match)
+        self.vm_b_events.append(event_complete)
+
+        # take queued event, should already been happened
+        event_stop = self.vm_a.event_wait('STOP')
+        self.vm_a_events.append(event_stop)
+
+        downtime = event_dist(event_stop, event_resume)
+        postcopy_time = event_dist(event_resume, event_complete)
+
+        assert downtime * 10 < postcopy_time
+        if debug:
+            print('downtime:', downtime)
+            print('postcopy_time:', postcopy_time)
+
+        # check that there are no bitmaps stored on source
+        self.vm_a_events += self.vm_a.get_qmp_events()
+        self.vm_a.shutdown()
+        self.vm_a.launch()
+        check_bitmaps(self.vm_a, 0)
+
+        # check that bitmaps are migrated and persistence works
+        check_bitmaps(self.vm_b, nb_bitmaps)
+        self.vm_b.shutdown()
+        # recreate vm_b, so there is no incoming option, which prevents
+        # loading bitmaps from disk
+        self.vm_b = iotests.VM(path_suffix='b').add_drive(disk_b)
+        self.vm_b.launch()
+        check_bitmaps(self.vm_b, nb_bitmaps)
+
+        # Check content of migrated bitmaps. Still, don't waste time checking
+        # every bitmap
+        for i in range(0, nb_bitmaps, 5):
+            result = self.vm_b.qmp('x-debug-block-dirty-bitmap-sha256',
+                                   node='drive0', name='bitmap{}'.format(i))
+            sha = self.discards1_sha256 if i % 2 else self.all_discards_sha256
+            self.assert_qmp(result, 'return/sha256', sha)
+
+    def test_early_shutdown_destination(self):
+        self.start_postcopy()
+
+        self.vm_b_events += self.vm_b.get_qmp_events()
+        self.vm_b.shutdown()
+        # recreate vm_b, so there is no incoming option, which prevents
+        # loading bitmaps from disk
+        self.vm_b = iotests.VM(path_suffix='b').add_drive(disk_b)
+        self.vm_b.launch()
+        check_bitmaps(self.vm_b, 0)
 
-        s = 0x8000
-        while s < write_size:
-            self.vm_b.hmp_qemu_io('drive0', 'write %d %d' % (s, chunk))
-            s += 0x10000
+        # Bitmaps will be lost if we just shutdown the vm, as they are marked
+        # to skip storing to disk when prepared for migration. And that's
+        # correct, as actual data may be modified in target vm, so we play
+        # safe.
+        # Still, this mark would be taken away if we do 'cont', and bitmaps
+        # become persistent again. (see iotest 169 for such behavior case)
+        result = self.vm_a.qmp('query-status')
+        assert not result['return']['running']
+        self.vm_a_events += self.vm_a.get_qmp_events()
+        self.vm_a.shutdown()
+        self.vm_a.launch()
+        check_bitmaps(self.vm_a, 0)
+
+    def test_early_kill_source(self):
+        self.start_postcopy()
+
+        self.vm_a_events = self.vm_a.get_qmp_events()
+        self.vm_a.kill()
+
+        self.vm_a.launch()
 
-        result = self.vm_b.qmp('query-block');
-        while len(result['return'][0]['dirty-bitmaps']) > 1:
-            time.sleep(2)
-            result = self.vm_b.qmp('query-block');
+        match = {'data': {'status': 'completed'}}
+        e_complete = self.vm_b.event_wait('MIGRATION', match=match)
+        self.vm_b_events.append(e_complete)
 
-        result = self.vm_b.qmp('x-debug-block-dirty-bitmap-sha256',
-                               node='drive0', name='bitmap')
+        check_bitmaps(self.vm_a, 0)
+        check_bitmaps(self.vm_b, 0)
 
-        self.assert_qmp(result, 'return/sha256', sha256);
 
 if __name__ == '__main__':
-    iotests.main(supported_fmts=['qcow2'], supported_cache_modes=['none'],
-                 supported_protocols=['file'])
+    iotests.main(supported_fmts=['qcow2'])
diff --git a/tests/qemu-iotests/199.out b/tests/qemu-iotests/199.out
index ae1213e6f8..8d7e996700 100644
--- a/tests/qemu-iotests/199.out
+++ b/tests/qemu-iotests/199.out
@@ -1,5 +1,5 @@
-.
+...
 ----------------------------------------------------------------------
-Ran 1 tests
+Ran 3 tests
 
 OK
diff --git a/tests/qemu-iotests/group b/tests/qemu-iotests/group
index 1d0252e1f0..806044642c 100644
--- a/tests/qemu-iotests/group
+++ b/tests/qemu-iotests/group
@@ -112,7 +112,7 @@
 088 rw quick
 089 rw auto quick
 090 rw auto quick
-091 rw migration
+091 rw migration quick
 092 rw quick
 093 throttle
 094 rw quick
@@ -186,7 +186,7 @@
 162 quick
 163 rw
 165 rw quick
-169 rw quick migration
+169 rw migration
 170 rw auto quick
 171 rw quick
 172 auto
@@ -197,9 +197,9 @@
 177 rw auto quick
 178 img
 179 rw auto quick
-181 rw auto migration
+181 rw auto migration quick
 182 rw quick
-183 rw migration
+183 rw migration quick
 184 rw auto quick
 185 rw
 186 rw auto
@@ -216,9 +216,9 @@
 198 rw
 199 rw migration
 200 rw
-201 rw migration
+201 rw migration quick
 202 rw quick
-203 rw auto migration
+203 rw auto migration quick
 204 rw quick
 205 rw quick
 206 rw