From a50c1f57e491ba17c0fcb7d285dfe04770be0a70 Mon Sep 17 00:00:00 2001 From: Alberto Garcia Date: Fri, 10 Apr 2020 14:18:15 +0200 Subject: [PATCH] qcow2: Add incompatibility note between backing files and raw external data files Backing files and raw external data files are mutually exclusive. The documentation of the raw external data bit (in autoclear_features) already indicates that, but we should also mention it on the other side. Suggested-by: Eric Blake Signed-off-by: Alberto Garcia Message-Id: <20200410121816.8334-1-berto@igalia.com> Reviewed-by: Eric Blake Signed-off-by: Kevin Wolf --- docs/interop/qcow2.txt | 3 +++ 1 file changed, 3 insertions(+) diff --git a/docs/interop/qcow2.txt b/docs/interop/qcow2.txt index 640e0eca40..298a031310 100644 --- a/docs/interop/qcow2.txt +++ b/docs/interop/qcow2.txt @@ -25,6 +25,9 @@ The first cluster of a qcow2 image contains the file header: is stored (NB: The string is not null terminated). 0 if the image doesn't have a backing file. + Note: backing files are incompatible with raw external data + files (auto-clear feature bit 1). + 16 - 19: backing_file_size Length of the backing file name in bytes. Must not be longer than 1023 bytes. Undefined if the image doesn't have