From 7f75a07d50710e7f1371c4b248e0550549f77ead Mon Sep 17 00:00:00 2001 From: Max Reitz Date: Wed, 3 Sep 2014 00:25:09 +0200 Subject: docs/qcow2: Limit refcount_order to [0, 6] 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 Signed-off-by: Max Reitz Signed-off-by: Kevin Wolf --- docs/specs/qcow2.txt | 1 + 1 file changed, 1 insertion(+) (limited to 'docs') diff --git a/docs/specs/qcow2.txt b/docs/specs/qcow2.txt index 0a878aa95d..121dfc8cc1 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 -- cgit v1.2.1