Specify the upper limit of refcount_order to be 6 (that is,
refcount_bits = 64). Any larger value does not make much sense when all
offsets, sizes, cluster counts etc. "only" have a width of 64 bit as
well, and very large values would be very difficult to support.
Therefore, just cap it at the largest reasonable value.
Suggested-by: Eric Blake <ebl...@redhat.com>
Signed-off-by: Max Reitz <mre...@redhat.com>
---
docs/specs/qcow2.txt | 1 +
1 file changed, 1 insertion(+)
diff --git a/docs/specs/qcow2.txt b/docs/specs/qcow2.txt
index 0a878aa..121dfc8 100644
--- a/docs/specs/qcow2.txt
+++ b/docs/specs/qcow2.txt
@@ -110,6 +110,7 @@ in the description of a field.
in bits: refcount_bits = 1 << refcount_order). For version
2
images, the order is always assumed to be 4
(i.e. refcount_bits = 16).
+ This value may not exceed 6 (i.e. refcount_bits = 64).
100 - 103: header_length
Length of the header structure in bytes. For version 2
--
2.1.0
