Re: [Qemu-devel] QCow2 compression

2016-03-04 Thread mgreger
Eric Blake wrote: > [any way you could convince your mailer to not break threading?] > > On 03/03/2016 09:24 PM, mgre...@cinci.rr.com wrote: > >> > >> The zeros are not part of the compressed data, though, that's why the > >> Compressed Cluster Descriptor indicates a shorter size. Had ano

Re: [Qemu-devel] QCow2 compression

2016-03-04 Thread Eric Blake
[any way you could convince your mailer to not break threading?] On 03/03/2016 09:24 PM, mgre...@cinci.rr.com wrote: >> >> The zeros are not part of the compressed data, though, that's why the >> Compressed Cluster Descriptor indicates a shorter size. Had another >> compressed cluster been writt

Re: [Qemu-devel] QCow2 compression

2016-03-03 Thread mgreger
> > I have for example a compressed cluster with an L2 entry value of 4A > > C0 00 00 00 3D 97 50. This would lead me to believe the cluster starts > > at offset 0x3D9750 and has a length of 0x2B 512-byte sectors (or 0x2B > > times 0x200 = 0x5600). Added to the offset this would give an end for

Re: [Qemu-devel] QCow2 compression

2016-02-29 Thread Eric Blake
On 02/29/2016 07:01 AM, Kevin Wolf wrote: >> I have for example a compressed cluster with an L2 entry value of 4A >> C0 00 00 00 3D 97 50. This would lead me to believe the cluster starts >> at offset 0x3D9750 and has a length of 0x2B 512-byte sectors (or 0x2B >> times 0x200 = 0x5600). Added to the

Re: [Qemu-devel] QCow2 compression

2016-02-29 Thread Eric Blake
On 02/29/2016 07:59 AM, Eric Blake wrote: >> an L2 entry value of 4A C0 00 00 00 3D 97 50. > > So with default 64k clusters, x = 62 - (16 - 8) = 54. Bits 0-54 are the > host cluster offset, or 0x003d9750, but that is in terms of host > sectors. The comment in block/qcow2.c is telling, and perha

Re: [Qemu-devel] QCow2 compression

2016-02-29 Thread Eric Blake
On 02/26/2016 10:00 PM, mgre...@cinci.rr.com wrote: > Hello, I am hoping someone here can help me. I am implementing QCow2 support > for a PC emulator project and have a couple questions regarding compression I > haven't been able to figure out on my own. [Can you convince your mailer to wrap lo

Re: [Qemu-devel] QCow2 compression

2016-02-29 Thread Kevin Wolf
[ Cc: qemu-block ] Am 27.02.2016 um 06:00 hat mgre...@cinci.rr.com geschrieben: > Hello, I am hoping someone here can help me. I am implementing QCow2 > support for a PC emulator project and have a couple questions > regarding compression I haven't been able to figure out on my own. > > First som

[Qemu-devel] QCow2 compression

2016-02-26 Thread mgreger
Hello, I am hoping someone here can help me. I am implementing QCow2 support for a PC emulator project and have a couple questions regarding compression I haven't been able to figure out on my own. First some background: I am using the information I found at https://people.gnome.org/~markmc/qco