On Thu, 20 Feb 2020 at 16:11, Max Reitz <mre...@redhat.com> wrote:
>
> If a protocol driver does not support image creation, we can see whether
> maybe the file exists already. If so, just truncating it will be
> sufficient.
>
> Signed-off-by: Max Reitz <mre...@redhat.com>
> Message-Id: <20200122164532.178040-3-mre...@redhat.com>
> Signed-off-by: Max Reitz <mre...@redhat.com>
Hi; Coverity thinks there's a memory leak in the error
codepaths in this function (CID 1419884): is it right?
> +static int bdrv_create_file_fallback(const char *filename, BlockDriver *drv,
> + QemuOpts *opts, Error **errp)
> +{
> + BlockBackend *blk;
> + QDict *options = qdict_new();
We create the QDict here...
> + int64_t size = 0;
> + char *buf = NULL;
> + PreallocMode prealloc;
> Error *local_err = NULL;
> int ret;
>
> + size = qemu_opt_get_size_del(opts, BLOCK_OPT_SIZE, 0);
> + buf = qemu_opt_get_del(opts, BLOCK_OPT_PREALLOC);
> + prealloc = qapi_enum_parse(&PreallocMode_lookup, buf,
> + PREALLOC_MODE_OFF, &local_err);
> + g_free(buf);
> + if (local_err) {
> + error_propagate(errp, local_err);
> + return -EINVAL;
...but here and in other error return paths we don't
free it (I think that might need a qobject_unref() but
am not sure).
> + }
> +
> + if (prealloc != PREALLOC_MODE_OFF) {
> + error_setg(errp, "Unsupported preallocation mode '%s'",
> + PreallocMode_str(prealloc));
> + return -ENOTSUP;
> + }
(You could probably postpone qdict_new() to here to avoid
having to change the error handling paths above this point, but
you still need to deal with the error path for blk_new_open failing.)
> +
> + qdict_put_str(options, "driver", drv->format_name);
> +
> + blk = blk_new_open(filename, NULL, options,
> + BDRV_O_RDWR | BDRV_O_RESIZE, errp);
> + if (!blk) {
> + error_prepend(errp, "Protocol driver '%s' does not support image "
> + "creation, and opening the image failed: ",
> + drv->format_name);
> + return -EINVAL;
> + }
I guess for error-paths after blk_new_open() succeeds
that the blk object owns the options dictionary and
will deal with unreffing it for us?
> +
> + size = create_file_fallback_truncate(blk, size, errp);
> + if (size < 0) {
> + ret = size;
> + goto out;
> + }
> +
> + ret = create_file_fallback_zero_first_sector(blk, size, errp);
> + if (ret < 0) {
> + goto out;
> + }
> +
> + ret = 0;
> +out:
> + blk_unref(blk);
> + return ret;
> +}
thanks
-- PMM
