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Re: [Qemu-devel] No error report when using the qemu-img.exetoconvert a
From: |
Kevin Wolf |
Subject: |
Re: [Qemu-devel] No error report when using the qemu-img.exetoconvert a disk to vmdk format which is saved on a disk that has nomorespace |
Date: |
Thu, 24 Sep 2015 11:14:15 +0200 |
User-agent: |
Mutt/1.5.21 (2010-09-15) |
Am 24.09.2015 um 10:01 hat Guangmu Zhu geschrieben:
> Hi Kevin,
>
> I tried the patch you provide, and I haven't seen that problem yet. If the
> disk
> space is full, an error will be reported with the message "Invalid argument"
> and the program will stop.
>
> Will you merge the patch to the master?
I'll post it in a separate email thread as a proper patch now in order
to give people a chance to review it. After that, I'll include it in a
pull request for master, but it might still be a few days until then.
Kevin
> diff --git a/block/raw-win32.c b/block/raw-win32.c
> index 68f2338..b562c94 100644
> --- a/block/raw-win32.c
> +++ b/block/raw-win32.c
> @@ -119,9 +119,9 @@ static int aio_worker(void *arg)
> case QEMU_AIO_WRITE:
> count = handle_aiocb_rw(aiocb);
> if (count == aiocb->aio_nbytes) {
> - count = 0;
> + ret = 0;
> } else {
> - count = -EINVAL;
> + ret = -EINVAL;
> }
> break;
> case QEMU_AIO_FLUSH:
>
> -------------------------------------------------
>
> I'll try the patch and report in a week for I'm too busy these days. And if I
> could, I would like to help to maintain the Windows backend.
>
> Sincerely.
> Guangmu Zhu
>
> -------------------------------------------------
>
> Am 23.09.2015 um 13:30 hat Guangmu Zhu geschrieben:
> > If the "BlockDriver" is "bdrv_vmdk", the function "vmdk_co_write" will be
> > called instead. In function "vmdk_write_extent" I see "ret = bdrv_pwrite
> > (extent->file, write_offset, write_buf, write_len);". So the "extend->file"
> is
> > "bdrv_file", is it?
>
> Yes, exactly. You'll go through bdrv_vmdk first, and then the nested
> call goes to bdrv_file.
>
> > -------------------------------------------------
> >
> > Correct a mistake:
> > So though the "count" would be "-EINVAL" if error occurred while writing
> > some
> > file, the return value will always be zero. Maybe I missed something?
>
> I think you're right. Instead of setting count = 0/-EINVAL in
> aio_worker, we should be setting ret.
>
> Can you try the patch below and report back?
>
> > 3. The "bs->drv->bdrv_aio_writev" is function "raw_aio_writev" in file
> > "raw-win32.c" and the quemu-img uses synchronous IO always, so the function
> > "paio_submit" in the same file will be called. This function submits the
> "aio"
> > to "worker_thread" with the callback "aio_worker". There are some codes in
> > "aio_worker":
> >
> > ssize_t ret = 0;
> > ......
> > case QEMU_AIO_WRITE:
> > count = handle_aiocb_rw(aiocb);
> > if (count == aiocb->aio_nbytes) {
> > count = 0;
> > } else {
> > count = -EINVAL;
> > }
> > break;
> > ......
> > return ret;
>
> Independently of your problem, the code in aio_worker() looks a bit
> fishy, because handle_aiocb_rw() can't distinguish between an error
> and 0 bytes transferred.
>
> For writes, that probably doesn't matter, but for reads, I think we
> return a successful read of zeroes instead of signalling an error. This
> might need another patch.
>
> Generally, the Windows backend is not getting a lot of attention and
> could use someone who checks it, cleans it up and fixes bugs.
>
> Kevin
>
>
> diff --git a/block/raw-win32.c b/block/raw-win32.c
> index 68f2338..b562c94 100644
> --- a/block/raw-win32.c
> +++ b/block/raw-win32.c
> @@ -119,9 +119,9 @@ static int aio_worker(void *arg)
> case QEMU_AIO_WRITE:
> count = handle_aiocb_rw(aiocb);
> if (count == aiocb->aio_nbytes) {
> - count = 0;
> + ret = 0;
> } else {
> - count = -EINVAL;
> + ret = -EINVAL;
> }
> break;
> case QEMU_AIO_FLUSH:
- [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, Guangmu Zhu, 2015/09/22
- 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, 2015/09/22
- Re: [Qemu-devel] No error report when using the qemu-img.exe toconvert a disk to vmdk format which is saved on a disk that has no morespace, Guangmu Zhu, 2015/09/23
- Re: [Qemu-devel] No error report when using the qemu-img.exe toconvert a disk to vmdk format which is saved on a disk that has no morespace, Guangmu Zhu, 2015/09/23
- Re: [Qemu-devel] No error report when using the qemu-img.exe toconvert a disk to vmdk format which is saved on a disk that has no morespace, Guangmu Zhu, 2015/09/23
- Re: [Qemu-devel] No error report when using the qemu-img.exe toconvert a disk to vmdk format which is saved on a disk that has no morespace, Kevin Wolf, 2015/09/23
- Re: [Qemu-devel] No error report when using the qemu-img.exetoconvert a disk to vmdk format which is saved on a disk that has nomorespace, Guangmu Zhu, 2015/09/23
- Re: [Qemu-devel] No error report when using the qemu-img.exetoconvert a disk to vmdk format which is saved on a disk that has nomorespace, Guangmu Zhu, 2015/09/24
- Re: [Qemu-devel] No error report when using the qemu-img.exetoconvert a disk to vmdk format which is saved on a disk that has nomorespace,
Kevin Wolf <=