diff options
| -rw-r--r-- | docs/interop/qcow2.txt | 14 |
1 files changed, 12 insertions, 2 deletions
diff --git a/docs/interop/qcow2.txt b/docs/interop/qcow2.txt index bfb97cfde3..8c3098d8d9 100644 --- a/docs/interop/qcow2.txt +++ b/docs/interop/qcow2.txt @@ -170,11 +170,11 @@ be stored. Each extension has a structure like the following: Byte 0 - 3: Header extension type: 0x00000000 - End of the header extension area - 0xE2792ACA - Backing file format name + 0xE2792ACA - Backing file format name string 0x6803f857 - Feature name table 0x23852875 - Bitmaps extension 0x0537be77 - Full disk encryption header pointer - 0x44415441 - External data file name + 0x44415441 - External data file name string other - Unknown header extension, can be safely ignored @@ -196,6 +196,16 @@ data of compatible features that it doesn't support. Compatible features that need space for additional data can use a header extension. +== String header extensions == + +Some header extensions (such as the backing file format name and the external +data file name) are just a single string. In this case, the header extension +length is the string length and the string is not '\0' terminated. (The header +extension padding can make it look like a string is '\0' terminated, but +neither is padding always necessary nor is there a guarantee that zero bytes +are used for padding.) + + == Feature name table == The feature name table is an optional header extension that contains the name |