docs/interop/qcow2.rst

118                                 An External Data File Name header extension may
149                     Bit 0:      Bitmaps extension bit
151                                 extension data.
154                                 bitmaps extension present.
156                                 If the bitmaps extension is present but this
157                                 bit is unset, the bitmaps extension data must be
253 be stored. Each extension has a structure like the following::
255     Byte  0 -  3:   Header extension type:
256                         0x00000000 - End of the header extension area
259                         0x23852875 - Bitmaps extension
262                         other      - Unknown header extension, can be safely
265           4 -  7:   Length of the header extension data
267           8 -  n:   Header extension data
269           n -  m:   Padding to round up the header extension size to the next
272 Unless stated otherwise, each header extension type shall appear at most once
276 the remaining space between the end of the header extension area and the end of
280 need space for additional data can use a header extension.
287 data file name) are just a single string. In this case, the header extension
289 extension padding can make it look like a string is ``\0`` terminated, but
297 The feature name table is an optional header extension that contains the name
303 the header extension data. Each entry looks like this::
317 Bitmaps extension
320 The bitmaps extension is an optional header extension. It provides the ability
325 The data of the extension should be considered consistent only if the
328 The fields of the bitmaps extension are::
352 of the ``LUKS`` crypt method. The header extension must be absent for
396   | QCow2 header extension X    |
397   | QCow2 header extension FDE  |
398   | QCow2 header extension ...  |
399   | QCow2 header extension Z    |
758 As mentioned above, the bitmaps extension provides the ability to store bitmaps
779 and length are given by the header extension fields ``bitmap_directory_offset`` and
858                     within the bitmaps extension.