The cluster size of an image is the QcowHeader class member and may be obtained by dependent extension structures such as Qcow2BitmapExt for further bitmap table details print.
Signed-off-by: Andrey Shinkevich <andrey.shinkev...@virtuozzo.com> --- tests/qemu-iotests/qcow2_format.py | 19 ++++++++++++++----- 1 file changed, 14 insertions(+), 5 deletions(-) diff --git a/tests/qemu-iotests/qcow2_format.py b/tests/qemu-iotests/qcow2_format.py index 90eff92..eb99119 100644 --- a/tests/qemu-iotests/qcow2_format.py +++ b/tests/qemu-iotests/qcow2_format.py @@ -116,6 +116,10 @@ class Qcow2BitmapExt(Qcow2Struct): ('u64', '{:#x}', 'bitmap_directory_offset') ) + def __init__(self, data, cluster_size): + super().__init__(data=data) + self.cluster_size = cluster_size + def read_bitmap_directory(self, fd): self.bitmaps = [] fd.seek(self.bitmap_directory_offset) @@ -123,7 +127,8 @@ class Qcow2BitmapExt(Qcow2Struct): for n in range(self.nb_bitmaps): buf = fd.read(buf_size) - dir_entry = Qcow2BitmapDirEntry(data=buf) + dir_entry = Qcow2BitmapDirEntry(data=buf, + cluster_size=self.cluster_size) fd.seek(dir_entry.extra_data_size, FROM_CURRENT) bitmap_name = fd.read(dir_entry.name_size) dir_entry.name = bitmap_name.decode('ascii') @@ -159,8 +164,9 @@ class Qcow2BitmapDirEntry(Qcow2Struct): ('u32', '{}', 'extra_data_size') ) - def __init__(self, data): + def __init__(self, data, cluster_size): super().__init__(data=data) + self.cluster_size = cluster_size self.bitmap_table_bytes = self.bitmap_table_size \ * struct.calcsize('Q') @@ -205,11 +211,13 @@ class QcowHeaderExtension(Qcow2Struct): # then padding to next multiply of 8 ) - def __init__(self, magic=None, length=None, data=None, fd=None): + def __init__(self, magic=None, length=None, data=None, fd=None, + cluster_size=None): """ Support both loading from fd and creation from user data. For fd-based creation current position in a file will be used to read the data. + The cluster_size value may be obtained by dependent structures. This should be somehow refactored and functionality should be moved to superclass (to allow creation of any qcow2 struct), but then, fields @@ -243,7 +251,8 @@ class QcowHeaderExtension(Qcow2Struct): self.data_str = data_str if self.magic == QCOW2_EXT_MAGIC_BITMAPS: - self.obj = Qcow2BitmapExt(data=self.data) + self.obj = Qcow2BitmapExt(data=self.data, + cluster_size=cluster_size) else: self.obj = None @@ -318,7 +327,7 @@ class QcowHeader(Qcow2Struct): end = self.cluster_size while fd.tell() < end: - ext = QcowHeaderExtension(fd=fd) + ext = QcowHeaderExtension(fd=fd, cluster_size=self.cluster_size) if ext.magic == 0: break else: -- 1.8.3.1