| Message ID | 1409696709-27623-4-git-send-email-mreitz@redhat.com |
|---|---|
| State | New |
| Headers | show |
On 09/02/2014 04:25 PM, Max Reitz wrote: > 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> > --- > docs/specs/qcow2.txt | 1 + > 1 file changed, 1 insertion(+) Reviewed-by: Eric Blake <eblake@redhat.com> > > 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 >
On Wed, Sep 03, 2014 at 12:25:09AM +0200, Max Reitz wrote: > 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> > --- > docs/specs/qcow2.txt | 1 + > 1 file changed, 1 insertion(+) Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
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
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> --- docs/specs/qcow2.txt | 1 + 1 file changed, 1 insertion(+)