On 3/29/19 11:40 AM, Richard W.M. Jones wrote: > > I tested this version of qemu against the nbdkit test suite and it > passed. > > It also fixes the problem with qemu-img convert: > > $ ./nbdkit -U - memory size=511 --run 'qemu-img convert $nbd /var/tmp/out' > > There are a couple of issues though (I don't think you'll think they > are bugs). > > Firstly it rounds up the size to 512 bytes. eg. /var/tmp/out above is > 512 bytes, and qemu-img info shows the virtual size as 512 bytes.
Well, that's the long-standing problem that qemu rounds up to sector boundaries, instead of being byte-accurate. Not going to get fixed for 4.0, but I've got my on it for 4.1. > > Secondly I still can't open the INT64_MAX image which as you will > recall has a 511 byte tail: > > $ ./nbdkit -U - memory size=$((2**63 - 1)) --run 'qemu-img info $nbd' > qemu-img: Could not open 'nbd:unix:/tmp/nbdkitTimYSJ/socket': Could not > read image for determining its format: File too large Correct, fallout of the point above (rounding up overflows). > > ... yet the 2^63-512 image can be opened (same as before): > > $ ./nbdkit -U - memory size=$((2**63 - 512)) --run 'qemu-img info $nbd' > image: nbd+unix://?socket=/tmp/nbdkitHSAzNz/socket > file format: raw > virtual size: -8388607T (9223372036854775296 bytes) > disk size: unavailable > > I've just noticed that the virtual size negative (also in upstream > qemu). That looks like a bug too ... Yes, it does. I'll see if I can find a quick fix for that formatting routine. -- Eric Blake, Principal Software Engineer Red Hat, Inc. +1-919-301-3226 Virtualization: qemu.org | libvirt.org
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