def test_dirty_bitmap(tmpdir):
size = 1024**2
# Create image with empty bitmap.
img = str(tmpdir.join("img.qcow2"))
qemu_img.create(img, "qcow2", size=size)
qemu_img.bitmap_add(img, "b0")
# Write data to image, modifying the bitmap.
with qemu_nbd.open(img, "qcow2") as c:
# This will allocate one cluster. By default bitmap granularity is also
# one cluster, so this will make the first extent dirty.
c.write(0, b"a")
c.flush()
# Read dirty extents.
with qemu_nbd.open(img, "qcow2", read_only=True, bitmap="b0") as c:
extents = c.extents(0, size)[nbd.QEMU_DIRTY_BITMAP + "b0"]
bitmap = qemu_img.info(img)["format-specific"]["data"]["bitmaps"][0]
assert extents == [
nbd.Extent(length=bitmap["granularity"], flags=nbd.EXTENT_DIRTY),
nbd.Extent(length=size - bitmap["granularity"], flags=0),
]
def test_add_bitmap(tmpdir):
size = 10 * 1024**2
img = str(tmpdir.join("img.qcow2"))
qemu_img.create(img, "qcow2", size=size)
qemu_img.bitmap_add(img, "b0")
bitmaps = qemu_img.info(img)["format-specific"]["data"]["bitmaps"]
assert bitmaps == [
{"name": "b0", "flags": ["auto"], "granularity": 65536}
]
def test_dirty_extents(tmpdir):
size = 1024**2
# Create base image with empty dirty bitmap.
base = str(tmpdir.join("base.qcow2"))
qemu_img.create(base, "qcow2", size=size)
qemu_img.bitmap_add(base, "b0")
# Write data, modifying the dirty bitmap.
with qemu_nbd.open(base, "qcow2") as c:
c.write(0 * CLUSTER_SIZE, b"A" * CLUSTER_SIZE)
c.zero(1 * CLUSTER_SIZE, CLUSTER_SIZE)
c.flush()
# Create top image with empty dirty bitmap.
top = str(tmpdir.join("top.qcow2"))
qemu_img.create(top, "qcow2", backing_file=base, backing_format="qcow2")
qemu_img.bitmap_add(top, "b0")
# Write data, modifying the dirty bitmap.
with qemu_nbd.open(top, "qcow2") as c:
c.write(3 * CLUSTER_SIZE, b"B" * CLUSTER_SIZE)
c.zero(4 * CLUSTER_SIZE, CLUSTER_SIZE)
c.flush()
dirty_extents = list(client.extents(base, bitmap="b0"))
assert dirty_extents == [
DirtyExtent(start=0 * CLUSTER_SIZE,
length=2 * CLUSTER_SIZE,
dirty=True),
DirtyExtent(start=2 * CLUSTER_SIZE,
length=size - 2 * CLUSTER_SIZE,
dirty=False),
]
dirty_extents = list(client.extents(top, bitmap="b0"))
# Note: qemu-nbd reports dirty extents only for the top image.
assert dirty_extents == [
DirtyExtent(start=0 * CLUSTER_SIZE,
length=3 * CLUSTER_SIZE,
dirty=False),
DirtyExtent(start=3 * CLUSTER_SIZE,
length=2 * CLUSTER_SIZE,
dirty=True),
DirtyExtent(start=5 * CLUSTER_SIZE,
length=size - 5 * CLUSTER_SIZE,
dirty=False),
]
def test_dirty_extents(tmpdir):
size = 1024**2
# Create base image with empty dirty bitmap.
base = str(tmpdir.join("base.qcow2"))
qemu_img.create(base, "qcow2", size=size)
qemu_img.bitmap_add(base, "b0")
# Write data, modifying the dirty bitmap.
with qemu_nbd.open(base, "qcow2") as c:
c.write(0 * CLUSTER_SIZE, b"A" * CLUSTER_SIZE)
c.zero(1 * CLUSTER_SIZE, CLUSTER_SIZE)
c.flush()
# Create top image with empty dirty bitmap.
top = str(tmpdir.join("top.qcow2"))
qemu_img.create(top, "qcow2", backing_file=base, backing_format="qcow2")
qemu_img.bitmap_add(top, "b0")
# Write data, modifying the dirty bitmap.
with qemu_nbd.open(top, "qcow2") as c:
c.write(3 * CLUSTER_SIZE, b"B" * CLUSTER_SIZE)
c.zero(4 * CLUSTER_SIZE, CLUSTER_SIZE)
c.flush()
dirty_extents = list(client.extents(base, bitmap="b0"))
expected = [
# First cluster is dirty data.
DirtyExtent(
start=0 * CLUSTER_SIZE,
length=1 * CLUSTER_SIZE,
dirty=True,
zero=False),
# Second cluster is dirty zero.
DirtyExtent(
start=1 * CLUSTER_SIZE,
length=1 * CLUSTER_SIZE,
dirty=True,
zero=True),
# Third cluster is clean zero.
DirtyExtent(
start=2 * CLUSTER_SIZE,
length=size - 2 * CLUSTER_SIZE,
dirty=False,
zero=True),
]
log.debug("base image dirty extents: %s", dirty_extents)
assert dirty_extents == expected
dirty_extents = list(client.extents(top, bitmap="b0"))
# Note: qemu-nbd reports dirty extents only for the top image, but zero
# extents are read from the base image.
expected = [
# First cluster is clean data, read from base image.
DirtyExtent(
start=0 * CLUSTER_SIZE,
length=1 * CLUSTER_SIZE,
dirty=False,
zero=False),
# Second and third clusters are read from base image. Because they are
# both clean zero, they are merged.
DirtyExtent(
start=1 * CLUSTER_SIZE,
length=2 * CLUSTER_SIZE,
dirty=False,
zero=True),
# Forth cluster is a data extent modified in top image.
DirtyExtent(
start=3 * CLUSTER_SIZE,
length=1 * CLUSTER_SIZE,
dirty=True,
zero=False),
# Fifth cluster is a zero extent modifed in to image.
DirtyExtent(
start=4 * CLUSTER_SIZE,
length=1 * CLUSTER_SIZE,
dirty=True,
zero=True),
# The rest is clean zero extent.
DirtyExtent(
start=5 * CLUSTER_SIZE,
length=size - 5 * CLUSTER_SIZE,
dirty=False,
zero=True),
]
log.debug("top image dirty extents: %s", dirty_extents)
assert dirty_extents == expected