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| author | Max Reitz <mreitz@redhat.com> | 2014-09-03 00:25:09 +0200 |
|---|---|---|
| committer | Kevin Wolf <kwolf@redhat.com> | 2014-10-23 15:34:02 +0200 |
| commit | 7f75a07d50710e7f1371c4b248e0550549f77ead (patch) | |
| tree | f2ad191552ce745c145c0e07dce6c01aad1f2fb7 /docs | |
| parent | 4b318d6ca66545e59eafbf595f66e31bf1625d9a (diff) | |
| download | qemu-7f75a07d50710e7f1371c4b248e0550549f77ead.tar.gz | |
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 <eblake@redhat.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Diffstat (limited to 'docs')
| -rw-r--r-- | docs/specs/qcow2.txt | 1 |
1 files changed, 1 insertions, 0 deletions
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 |