On Mon, Apr 01, 2019 at 03:04:16PM +0200, Kevin Wolf wrote: > Am 30.03.2019 um 16:07 hat Eric Blake geschrieben: > > Disk sizes close to INT64_MAX cause overflow, for some pretty > > ridiculous output: > > > > $ ./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 > > > > But there's no reason to have two separate implementations of integer > > to human-readable abbreviation, where one has overflow and stops at > > 'T', while the other avoids overflow and goes all the way to 'E'. With > > this patch, the output now claims 8EiB instead of -8388607T, which > > really is the correct rounding of largest file size supported by qemu > > (we could go 511 bytes larger if we used byte-accurate sizing instead > > of rounding up to the next sector boundary, but that wouldn't change > > the human-readable result). > > > > Reported-by: Richard W.M. Jones <rjo...@redhat.com> > > Signed-off-by: Eric Blake <ebl...@redhat.com> > > This is quite obviously a bug fix for some cases. This suggests that we > want it in 4.0. > > It is also an output change for other cases, like going from "8M" to > "8 MiB". We probably can't tell for sure whether some tools expect the > spelling "8M" (even if this is supposed to be the human interface and > tools should be using JSON) or feed the change back to qemu-img or > qemu-io (which accept "8M", but not "8 MiB" as sizes in most places). > This suggests that we shouldn't make this change as late as -rc2.
If it breaks our own tests, then it is possible to break other tools too. > So what is the conclusion? The safe option is to do the minimal fix for the existing code and look at the refactoring in the next dev cycle. Regards, Daniel -- |: https://berrange.com -o- https://www.flickr.com/photos/dberrange :| |: https://libvirt.org -o- https://fstop138.berrange.com :| |: https://entangle-photo.org -o- https://www.instagram.com/dberrange :|
