Re: [Xen-devel] can't boot from iso on cifs mount

[Vasiliy Tolstov <v.tolstov@xxxxxxxxx>]

Thanks for patch. But it not solve problem:
Now i have :
domid: 6
Using file /dev/disk/vbd/21-828 in read-write mode
Strip off blktap sub-type prefix to  (drv 'aio')
Watching /local/domain/0/device-model/6/logdirty/cmd
Watching /local/domain/0/device-model/6/command
Watching /local/domain/6/cpu
char device redirected to /dev/pts/5
qemu_map_cache_init nr_buckets = 10000 size 4194304
Could not open /var/run/tap/qemu-read-6
shared page at pfn feffd
buffered io page at pfn feffb
Guest uuid = c98c33c8-1891-41ec-96a0-984f3df80def
xen be: qdisk-5632: xen be: qdisk-5632: opening  with O_DIRECT failed,
trying write-through.
opening  with O_DIRECT failed, trying write-through.
populating video RAM at ff000000
mapping video RAM from ff000000
Register xen platform.
Done register platform.
platform_fixed_ioport: changed ro/rw state of ROM memory area. now is rw state.
xs_read(/local/domain/0/device-model/6/xen_extended_power_mgmt): read error
medium change watch on `hdc' (index: 1): aio:
I/O request not ready: 0, ptr: 0, port: 0, data: 0, count: 0, size: 0
Log-dirty: no command yet.
I/O request not ready: 0, ptr: 0, port: 0, data: 0, count: 0, size: 0
I/O request not ready: 0, ptr: 0, port: 0, data: 0, count: 0, size: 0
vcpu-set: watch node error.
I/O request not ready: 0, ptr: 0, port: 0, data: 0, count: 0, size: 0
xs_read(/local/domain/6/log-throttling): read error
qemu: ignoring not-understood drive `/local/domain/6/log-throttling'
medium change watch on `/local/domain/6/log-throttling' - unknown
device, ignored
xen be: qdisk-5632: xen be: qdisk-5632: opening  with O_DIRECT failed,
trying write-through.
opening  with O_DIRECT failed, trying write-through.
log_throttling disabled
qemu: ignoring not-understood drive `/local/domain/6/log-throttling'
medium change watch on `/local/domain/6/log-throttling' - unknown
device, ignored
vga s->lfb_addr = f0000000 s->lfb_end = f1000000
platform_fixed_ioport: changed ro/rw state of ROM memory area. now is rw state.
platform_fixed_ioport: changed ro/rw state of ROM memory area. now is ro state.


(XEN) HVM6: VGABios $Id: vgabios.c,v 1.67 2008/01/27 09:44:12 vruppert Exp $
(XEN) HVM6: VBE Bios $Id: vbe.c,v 1.60 2008/03/02 07:47:21 vruppert Exp $
(XEN) HVM6: Bochs BIOS - build: 06/23/99
(XEN) HVM6: $Revision: 1.221 $ $Date: 2008/12/07 17:32:29 $
(XEN) HVM6: Options: apmbios pcibios eltorito PMM
(XEN) HVM6:
(XEN) HVM6: ata0-0: PCHS=16383/16/63 translation=lba LCHS=1024/255/63
(XEN) HVM6: ata0 master: QEMU HARDDISK ATA-7 Hard-Disk (10246 MBytes)
(XEN) HVM6: IDE time out
(XEN) HVM6: ata1 master: QEMU DVD-ROM ATAPI-4 CD-Rom/DVD-Rom
(XEN) HVM6: IDE time out
(XEN) HVM6:
(XEN) HVM6:
(XEN) HVM6:
(XEN) HVM6: Press F12 for boot menu.
(XEN) HVM6:
(XEN) HVM6: Booting from Hard Disk...
(XEN) HVM6: Boot from Hard Disk failed: not a bootable disk
(XEN) HVM6:
(XEN) HVM6:
(XEN) HVM6: No bootable device.
(XEN) HVM6: Powering off in 30 seconds.
(XEN) hvm.c:1080:d6 All CPUs offline -- powering off.

2013/1/22 Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>:
> On Tue, 22 Jan 2013, Ian Campbell wrote:
>> Please don't top post.
>>
>> On Tue, 2013-01-22 at 05:38 +0000, Vasiliy Tolstov wrote:
>> > Thanks!
>> > I found, that now xl tries to open iso with O_DIRECT flag.
>> > open("/var/storage/iso/SW_DVD5_Windows_Svr_DC_EE_SE_Web_2008_R2_64Bit_Russian_w_SP1_MLF_X17-22616_vase.iso",
>> > O_RDONLY|O_DIRECT) = -1 EINVAL (Invalid argument)
>> > write(2, "qemu: could not open vbd '/local"..., 217) = 217
>
> xl? I guess you mean QEMU tries to open the ISO with O_DIRECT.
>
>
>> I guess CIFS doesn't support O_DIRECT. It looks like it does have mount
>> -o directio though, worth a try.
>>
>> I'm not sure what options exist to turn this off from the qemu side --
>> Stefano? I also have a feeling something changed in this regard in 4.2.x
>
> Given that you are not passing any device_model_version option to xl, I
> assume that you are running qemu-xen-traditional (ps should show that a
> binary called qemu-dm is running).
>
> If that is the case, there is currently no way to specify any flags.
> However the interesting bit is that qemu-xen-traditional opens files
> corresponding to emulated devices with BDRV_O_CACHE_WB and opens files
> corresponding to PV interfaces using BDRV_O_NOCACHE (this means
> O_DIRECT).
> This means that the failure should be caused by hw/xen_disk.c trying to
> opening the iso O_DIRECT. Paradoxically the PV inteface for a cdrom
> drive is usually never used AFAIK.
>
> Did the Windows PV drivers start using the PV cdrom interface all of a
> sudden?
>
> In any case I think that the best thing we could do it fall back to
> write-through (or should it be write-back? It might not be safe..) in
> case O_DIRECT fails. This is what qemu-xen does in such cases.
>
> Try this patch:
>
> ---
>
> diff --git a/hw/xen_disk.c b/hw/xen_disk.c
> index 33a5531..d6d71fe 100644
> --- a/hw/xen_disk.c
> +++ b/hw/xen_disk.c
> @@ -659,9 +659,16 @@ static int blk_init(struct XenDevice *xendev)
>         if (blkdev->bs) {
>             if (bdrv_open2(blkdev->bs, blkdev->filename, qflags,
>                             bdrv_find_format(blkdev->fileproto)) != 0) {
> -               bdrv_delete(blkdev->bs);
> -               blkdev->bs = NULL;
> -           }
> +                /* try without O_DIRECT */
> +                xen_be_printf(&blkdev->xendev, 0, "opening %s with O_DIRECT 
> failed, trying write-through.\n",
> +                        blkdev->filename);
> +                qflags &= BDRV_O_NOCACHE;
> +                if (bdrv_open2(blkdev->bs, blkdev->filename, qflags,
> +                            bdrv_find_format(blkdev->fileproto)) != 0) {
> +                    bdrv_delete(blkdev->bs);
> +                    blkdev->bs = NULL;
> +                }
> +            }
>         }
>         if (!blkdev->bs)
>             return -1;
>



-- 
Vasiliy Tolstov,
Clodo.ru
e-mail: v.tolstov@xxxxxxxxx
jabber: vase@xxxxxxxxx

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