From fe16c7ddf82b25e54cb76936a4cdf6bf9327ece5 Mon Sep 17 00:00:00 2001 From: Max Reitz Date: Thu, 30 Jul 2020 14:02:33 +0200 Subject: [PATCH 1/2] qcow2: Release read-only bitmaps when inactivated During migration, we release all bitmaps after storing them on disk, as long as they are (1) stored on disk, (2) not read-only, and (3) consistent. (2) seems arbitrary, though. The reason we do not release them is because we do not write them, as there is no need to; and then we just forget about all bitmaps that we have not written to the file. However, read-only persistent bitmaps are still in the file and in sync with their in-memory representation, so we may as well release them just like any R/W bitmap that we have updated. It leads to actual problems, too: After migration, letting the source continue may result in an error if there were any bitmaps on read-only nodes (such as backing images), because those have not been released by bdrv_inactive_all(), but bdrv_invalidate_cache_all() attempts to reload them (which fails, because they are still present in memory). Signed-off-by: Max Reitz Message-Id: <20200730120234.49288-2-mreitz@redhat.com> Tested-by: Peter Krempa Reviewed-by: Eric Blake Signed-off-by: Eric Blake --- block/qcow2-bitmap.c | 23 +++++++++++++++++++---- 1 file changed, 19 insertions(+), 4 deletions(-) diff --git a/block/qcow2-bitmap.c b/block/qcow2-bitmap.c index 1f38806ca6..8c34b2aef7 100644 --- a/block/qcow2-bitmap.c +++ b/block/qcow2-bitmap.c @@ -1562,11 +1562,22 @@ void qcow2_store_persistent_dirty_bitmaps(BlockDriverState *bs, Qcow2Bitmap *bm; if (!bdrv_dirty_bitmap_get_persistence(bitmap) || - bdrv_dirty_bitmap_readonly(bitmap) || bdrv_dirty_bitmap_inconsistent(bitmap)) { continue; } + if (bdrv_dirty_bitmap_readonly(bitmap)) { + /* + * Store the bitmap in the associated Qcow2Bitmap so it + * can be released later + */ + bm = find_bitmap_by_name(bm_list, name); + if (bm) { + bm->dirty_bitmap = bitmap; + } + continue; + } + need_write = true; if (check_constraints_on_bitmap(bs, name, granularity, errp) < 0) { @@ -1618,7 +1629,9 @@ void qcow2_store_persistent_dirty_bitmaps(BlockDriverState *bs, /* allocate clusters and store bitmaps */ QSIMPLEQ_FOREACH(bm, bm_list, entry) { - if (bm->dirty_bitmap == NULL) { + BdrvDirtyBitmap *bitmap = bm->dirty_bitmap; + + if (bitmap == NULL || bdrv_dirty_bitmap_readonly(bitmap)) { continue; } @@ -1641,6 +1654,7 @@ void qcow2_store_persistent_dirty_bitmaps(BlockDriverState *bs, g_free(tb); } +success: if (release_stored) { QSIMPLEQ_FOREACH(bm, bm_list, entry) { if (bm->dirty_bitmap == NULL) { @@ -1651,13 +1665,14 @@ void qcow2_store_persistent_dirty_bitmaps(BlockDriverState *bs, } } -success: bitmap_list_free(bm_list); return; fail: QSIMPLEQ_FOREACH(bm, bm_list, entry) { - if (bm->dirty_bitmap == NULL || bm->table.offset == 0) { + if (bm->dirty_bitmap == NULL || bm->table.offset == 0 || + bdrv_dirty_bitmap_readonly(bm->dirty_bitmap)) + { continue; } From edadc99a2ee90daeaaf4fba21d623ec8efe7c8e6 Mon Sep 17 00:00:00 2001 From: Max Reitz Date: Thu, 30 Jul 2020 14:02:34 +0200 Subject: [PATCH 2/2] iotests/169: Test source cont with backing bmap Test migrating from a VM with a persistent bitmap in the backing chain, and then continuing that VM after the migration Signed-off-by: Max Reitz Message-Id: <20200730120234.49288-3-mreitz@redhat.com> Reviewed-by: Eric Blake Signed-off-by: Eric Blake --- tests/qemu-iotests/169 | 64 +++++++++++++++++++++++++++++++++++++- tests/qemu-iotests/169.out | 4 +-- 2 files changed, 65 insertions(+), 3 deletions(-) diff --git a/tests/qemu-iotests/169 b/tests/qemu-iotests/169 index 2c5a132aa3..40afb15299 100755 --- a/tests/qemu-iotests/169 +++ b/tests/qemu-iotests/169 @@ -24,11 +24,12 @@ import time import itertools import operator import re -from iotests import qemu_img +from iotests import qemu_img, qemu_img_create, Timeout disk_a = os.path.join(iotests.test_dir, 'disk_a') disk_b = os.path.join(iotests.test_dir, 'disk_b') +base_a = os.path.join(iotests.test_dir, 'base_a') size = '1M' mig_file = os.path.join(iotests.test_dir, 'mig_file') mig_cmd = 'exec: cat > ' + mig_file @@ -234,6 +235,67 @@ for cmb in list(itertools.product((True, False), repeat=2)): inject_test_case(TestDirtyBitmapMigration, name, 'do_test_migration_resume_source', *list(cmb)) + +class TestDirtyBitmapBackingMigration(iotests.QMPTestCase): + def setUp(self): + qemu_img_create('-f', iotests.imgfmt, base_a, size) + qemu_img_create('-f', iotests.imgfmt, '-F', iotests.imgfmt, + '-b', base_a, disk_a, size) + + for f in (disk_a, base_a): + qemu_img('bitmap', '--add', f, 'bmap0') + + blockdev = { + 'node-name': 'node0', + 'driver': iotests.imgfmt, + 'file': { + 'driver': 'file', + 'filename': disk_a + }, + 'backing': { + 'node-name': 'node0-base', + 'driver': iotests.imgfmt, + 'file': { + 'driver': 'file', + 'filename': base_a + } + } + } + + self.vm = iotests.VM() + self.vm.launch() + + result = self.vm.qmp('blockdev-add', **blockdev) + self.assert_qmp(result, 'return', {}) + + # Check that the bitmaps are there + for node in self.vm.qmp('query-named-block-nodes', flat=True)['return']: + if 'node0' in node['node-name']: + self.assert_qmp(node, 'dirty-bitmaps[0]/name', 'bmap0') + + caps = [{'capability': 'events', 'state': True}] + result = self.vm.qmp('migrate-set-capabilities', capabilities=caps) + self.assert_qmp(result, 'return', {}) + + def tearDown(self): + self.vm.shutdown() + for f in (disk_a, base_a): + os.remove(f) + + def test_cont_on_source(self): + """ + Continue the source after migration. + """ + result = self.vm.qmp('migrate', uri=f'exec: cat > /dev/null') + self.assert_qmp(result, 'return', {}) + + with Timeout(10, 'Migration timeout'): + self.vm.wait_migration('postmigrate') + + result = self.vm.qmp('cont') + self.assert_qmp(result, 'return', {}) + + if __name__ == '__main__': iotests.main(supported_fmts=['qcow2'], supported_protocols=['file']) diff --git a/tests/qemu-iotests/169.out b/tests/qemu-iotests/169.out index 5c26d15c0d..cafb8161f7 100644 --- a/tests/qemu-iotests/169.out +++ b/tests/qemu-iotests/169.out @@ -1,5 +1,5 @@ -.................................... +..................................... ---------------------------------------------------------------------- -Ran 36 tests +Ran 37 tests OK