docs/interop/qcow2.rst

9 Likewise, the virtual disk as seen by the guest is divided into (guest)
43                     Note: QEMU as of today has an implementation limit of 2 MB
44                     as the maximum cluster size and won't be able to open images
53                     Note: QEMU has an implementation limit of 32 MB as
61                     hit other limits first (such as a file system's
162                                 be read as a consistent standalone raw image
195 as well as filled by zeros (which is equal to field absence), if software needs
209 3. An explicit value of 0 will have the same behavior as when the field is not
246 paragraph, i.e.  in the same manner as when this field is not present.
286 Some header extensions (such as the backing file format name and the external
356 its additional data, as well as the length of such data.
369 For the LUKS crypt method, the encryption header works as follows.
379 calculated as normal for the LUKS spec. ie the size of the LUKS
438    the virtual disk sector as the input tweak.
450    in the LUKS header, with the physical disk sector as the
471 large), note that some qcow2 metadata such as L1/L2 tables must point
475     QEMU has an implementation limit of 8 MB as the maximum refcount
482 obtained as follows::
514 Just as for refcounts, qcow2 uses a two-level structure for the mapping of
526 use).  Additionally, as cluster size increases, the maximum host
532 obtained as follows::
580     Bit       0:    If set to 1, the cluster reads as all zeros. The host
634 subclusters so they are treated the same as in images without this feature.
643 The first 64 bits have the same format as the standard L2 table entry described
663         32 - 63     Subcluster reads as zeros (one bit per subcluster)
665                     1: the subcluster reads as zeros. In this case the
692 as it doesn't need to be accurate in inactive L1 tables.
758 As mentioned above, the bitmaps extension provides the ability to store bitmaps
799                          (such as the auto flag or bitmap size) or data
812                          If it is set, the bitmap may be used as expected, extra
813                          data must be left as is.
815                          both it and its extra data be left as is.
831                     Granularity is calculated as
846                     For now, as no extra data is defined, extra_data_size is
867 Each bitmap is stored using a one-level structure (as opposed to two-level
879                       0: Cluster should be read as all zeros.
880                       1: Cluster should be read as all ones.
895 As noted above, bitmap data is stored in separate clusters, described by the
897 the image file can be obtained as follows::
935 flag is set, the software must consider the bitmap as ``enabled`` and start