On Tue 18 Apr 2017 03:57:24 PM CEST, Stefan Hajnoczi wrote:
> The measure subcommand calculates the size required by a new image file.
> This can be used by users or management tools that need to allocate
> space on an LVM volume, SAN LUN, etc before creating or converting an
> image file.
>
> Suggested-by: Maor Lipchuk <mlipc...@redhat.com>
> Signed-off-by: Stefan Hajnoczi <stefa...@redhat.com>
> ---
> v5:
> * Use UINT64_MAX instead of ~0ULL [Berto]
> * Document qemu-img measure ofmt, fmt, output_fmt, and snapshot_param
> [Berto]
> ---
[...]
> + QemuOptsList *create_opts = NULL;
> + bool image_opts = false;
> + uint64_t img_size = UINT64_MAX;
You are using UINT64_MAX here, but the rest of the function still uses
~0ULL.
> + case OPTION_SIZE:
> + {
> + int64_t sval;
> +
> + sval = cvtnum(optarg);
> + if (sval < 0) {
> + if (sval == -ERANGE) {
> + error_report("Image size must be less than 8 EiB!");
> + } else {
> + error_report("Invalid image size specified! You may use "
> + "k, M, G, T, P or E suffixes for ");
> + error_report("kilobytes, megabytes, gigabytes,
> terabytes, "
> + "petabytes and exabytes.");
> + }
> + goto out;
> + }
I don't know if this is very important, but even under 8 EiB there are
image sizes that 'qemu-img measure' will treat as valid but are not
actually possible to create:
$ qemu-img measure -O qcow2 --size 7E
required size: 1231640938414080
fully allocated size: 8071682173186342912
$ build/qemu-img create -o cluster_size=2M -f qcow2 img.qcow2 7E
Formatting 'img.qcow2', fmt=qcow2 size=8070450532247928832 encryption=off
cluster_size=2097152 lazy_refcounts=off refcount_bits=16
qemu-img: img.qcow2: The image size is too large for file format 'qcow2' (try
using a larger cluster size)
Berto
