Re: [Qemu-devel] No error report when using the qemu-img.exe to convert a disk to vmdk format which is saved on a disk that has no more space

[Kevin Wolf <kwolf@redhat.com>]

Am 22.09.2015 um 08:09 hat Guangmu Zhu geschrieben:
> I used the qemu-img.exe to convert a disk to vmdk format and the output file
> size could be 300 MB. However the left space of the disk the output file
> located on was about 200 MB. After a while, the left space had been zero but
> the program didn't stop or report any error. It was just going on as normal.
> 
> I read the source code and found the error report was controlled by
> "BlockdevOnError on_read_error, on_write_error" in "struct BlockDriverState",
> which had the default value "BLOCKDEV_ON_ERROR_REPORT" for "on_read_error" and
> "BLOCKDEV_ON_ERROR_ENOSPC" for "on_writer_error". The qemu-img.exe had no
> option to change the default behavior of the error report.
> 
> So I think if there were some ways to change the default value of the error
> report, it might be better. Further more, I suggest we could just add some
> codes to the "img_convert" function:
> 
>       1827:    out_blk = img_open("target", out_filename, out_fmt, flags, true,
> quiet);
>       1828:    if (!out_blk) {
>       1829:        ret = -1;
>       1830:        goto out;
>       1831:    }
>       1832:    out_bs = blk_bs(out_blk);
> ++ 1833:
> ++ 1834:    bdrv_set_on_error
> (out_bs, BLOCKDEV_ON_ERROR_REPORT, BLOCKDEV_ON_ERROR_REPORT);

This shouldn't make any difference for qemu-img. The error handling mode
is only for emulated devices in qemu proper.

It looks more like VMDK is somehow failing to report an error at all whn
it's running out of free disk space (though I couldn't spot an error in
the code at first sight).

Kevin