Re: [PATCH] fix free of event channel in blkfront

[tgh <tianguanhua@ncic.ac.cn>]

Hi
I am using the xen-3.0.3 on paravirtualVM
and I try to use xm block-attach dom6 /vm1/tp.img sda2 w
It seems to be ok, no error ,
but in the dom6 there is no sda2
and xm block-detach dom6 2050,it does not work
and xm block-list dom6 as follows ,

[root@= dev]# xm block-list dom6
Vdev BE handle state evt-ch ring-ref BE-path
2049 0 0 4 7 8 /local/domain/0/backend/vbd/127/2049
2050 0 0 3 8 665 /local/domain/0/backend/vbd/127/2050

I am confused about the function of these commands and how to use these
commands correctly

could you give me a help
Thanks in advance







Kasai Takanori 写道:
> Hi Steven,
>
>>>> We tested the xm block-attach/detach command.
>>>> It repeats block-attach/detach command for DomU and pv-on-hvm on
>>>> HVM Domain.
>>>> (block-attach -> block-detach -> block-attach -> block-detach -> ...)
>>>>
>>>> The block-attach command failed when repeating 256 times.
>>>
>>> I can't reproduce this - just tested 500 or so attach/detach pairs in
>>> a tight loop and worked for me. However I was using a regular domU -
>>> is it pv-on-hvm only? Can you give a more detailed repro case (or a
>>> script)?
>>
>> We tested only pv-on-hvm.
>> The script used when testing is appended.
>
> Sorry, the appended script was for network.
> It tested in the following scripts.
>
> -------------------------------------------------
> #!/bin/sh
> DomainID=25
> DevID=8448
> Count=0
>
> while :
> do
> echo "##### block-attach ##### $Count"
> xm block-attach $DomainID phy:/dev/sdc1 hde w
> sleep 1
> xm block-list $DomainID
> sleep 1
> echo "##### block-detach #####"
> xm block-detach $DomainID $DevID
> Count=`expr $Count + 1`
> #DevID=`expr $DevID + 1`
> sleep 1
> xm block-list $DomainID
> sleep 1
> done
> exit 0
> -------------------------------------------------
>
>
>> We will confirm it again with latest xen-unstable.hg.
>
> I confirmed it with up-to-date xen-unstable.hg. (cs 13282)
>
> It did not reproduce it in DomU.
> Because VBD was not able to be used, pv-on-hvm was not able to confirm
> it.
> The following errors occur.
>
> # insmod xen-vbd.ko
> xen-vbd: Unknown symbol irq_to_evtchn_port
> insmod: error inserting 'xen-vbd.ko': -1 Unknown symbol in module
>
>
> When reproducing it with pv-on-hvm, evtchn had not been liberated as
> follows.
>
> # xm block-attach <DomID> file:/test.img hde w
> # xm block-list <DomID>
> Vdev BE handle state evt-ch ring-ref BE-path
> 2049 0 0 4 6 8 /local/domain/0/backend/vbd/6/2049
> 8448 0 0 4 7 306 /local/domain/0/backend/vbd/6/8448
> # xm block-detach <DomID> 8448
> # xm block-list <DomID>
> Vdev BE handle state evt-ch ring-ref BE-path
> 2049 0 0 4 6 8 /local/domain/0/backend/vbd/6/2049
> # xm block-attach <DomID> file:/test.img hde w
> # xm block-list <DomID>
> Vdev BE handle state evt-ch ring-ref BE-path
> 2049 0 0 4 6 8 /local/domain/0/backend/vbd/6/2049
> 8448 0 0 4 8 306 /local/domain/0/backend/vbd/6/8448
> ^^^<= not 7
>
> If the evtchn number is liberated, it is sure to become the same number.
> The evtchn number keeps increase if it repeats.
> I will confirm whether to be liberated as follows and correctly.
>
> ・xen-unstable.hg : cs 13192
> Revert cset 13181:f087c013cf12 since the event channel is already
> unbound via
> blkif_free() -> unbind_from_irqhandler() -> unbind_from_irq()
>
>
> Thanks,
>
> -- 
> Takanori Kasai
>
>
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