[PATCH] qcow2: Explicit mention of padding bytes

[Eric Blake <eblake@redhat.com>]

Although we already covered the need for padding bytes with our
changes in commit 3ae3fcfa, commit 66fcbca5 just added one byte and
relied on the earlier text for implicitly covering 7 padding bytes.
For consistency with other parts of the header, it does not hurt to be
explicit that this version of the header is using padding bytes, and
if we later add other extension fields, we can rework the allocation
of those padding bytes to match those additions.

Signed-off-by: Eric Blake <eblake@redhat.com>
---
 docs/interop/qcow2.txt | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/docs/interop/qcow2.txt b/docs/interop/qcow2.txt
index 5597e244746e..193ac7c5c1af 100644
--- a/docs/interop/qcow2.txt
+++ b/docs/interop/qcow2.txt
@@ -209,6 +209,8 @@ version 2.
                     Available compression type values:
                         0: zlib <https://www.zlib.net/>

+          105 - m:  Zero padding to round up the header size to the next
+                    multiple of 8.

 === Header padding ===

-- 
2.25.1