can't unmount

can't unmount

[K. Richard Pixley]

  I'm running into a situation where I can't unmount a mounted 
snapshot.  It shows "busy" even though neither lsof nor fuser show any 
open files.  Umount -f doesn't work although umount -l does.

Is there anything else I can do to debug this scenario or to clear the 
busy status myself?  Or am I down to rebooting each time?

This is on stock ubuntu-10.04, x86.

--rich

Re: can't unmount

[K. Richard Pixley]

  And should I be worried about what umount -l might be leaving behind?  
(eg, any unfreed kernel resources)  Or is that a reasonable way to deal 
with this situation on an ongoing basis?

--rich

On 8/12/10 08:55 , K. Richard Pixley wrote:
>  I'm running into a situation where I can't unmount a mounted 
> snapshot.  It shows "busy" even though neither lsof nor fuser show any 
> open files.  Umount -f doesn't work although umount -l does.
>
> Is there anything else I can do to debug this scenario or to clear the 
> busy status myself?  Or am I down to rebooting each time?
>
> This is on stock ubuntu-10.04, x86.
>
> --rich

Re: can't unmount

[C Anthony Risinger]

On Aug 12, 2010, at 10:58 AM, "K. Richard Pixley" <rich@noir.com> wrote:

> And should I be worried about what umount -l might be leaving
> behind?  (eg, any unfreed kernel resources)  Or is that a reasonable
> way to deal with this situation on an ongoing basis?
>
> --rich
>
> On 8/12/10 08:55 , K. Richard Pixley wrote:
>> I'm running into a situation where I can't unmount a mounted
>> snapshot.  It shows "busy" even though neither lsof nor fuser show
>> any open files.  Umount -f doesn't work although umount -l does.
>>
>> Is there anything else I can do to debug this scenario or to clear
>> the busy status myself?  Or am I down to rebooting each time?
>>
>> This is on stock ubuntu-10.04, x86.
>>
>> --rich

You are lazy unmounting, as I understand, you are essentially just
hiding the fact that the mount was busy to userspace... The mount will
remain active in the kernel until you resolve whatever was stopping
umount in the first place; kernel will then silently unmount.

Does this affect all of your mounted snapshots, or only a particular
one?

C Anthony [mobile]

Re: can't unmount

[K. Richard Pixley]

  On 8/12/10 10:46 , C Anthony Risinger wrote:
> On Aug 12, 2010, at 10:58 AM, "K. Richard Pixley"<rich@noir.com>  wrote:
>> And should I be worried about what umount -l might be leaving
>> behind?  (eg, any unfreed kernel resources)  Or is that a reasonable
>> way to deal with this situation on an ongoing basis?
>>
>> On 8/12/10 08:55 , K. Richard Pixley wrote:
>>> I'm running into a situation where I can't unmount a mounted
>>> snapshot.  It shows "busy" even though neither lsof nor fuser show
>>> any open files.  Umount -f doesn't work although umount -l does.
>>>
>>> Is there anything else I can do to debug this scenario or to clear
>>> the busy status myself?  Or am I down to rebooting each time?
>>>
>>> This is on stock ubuntu-10.04, x86.
> You are lazy unmounting, as I understand, you are essentially just
> hiding the fact that the mount was busy to userspace... The mount will
> remain active in the kernel until you resolve whatever was stopping
> umount in the first place; kernel will then silently unmount.
Understood.
> Does this affect all of your mounted snapshots, or only a particular
> one?
I'm only mounting one at a time so I haven't noticed.  Will check next 
time it occurs.

--rich

Re: can't unmount

[C Anthony Risinger]

On Aug 12, 2010, at 12:57 PM, "K. Richard Pixley" <rich@noir.com> wrote:

> On 8/12/10 10:46 , C Anthony Risinger wrote:
>> On Aug 12, 2010, at 10:58 AM, "K. Richard Pixley"<rich@noir.com>
>> wrote:
>>> And should I be worried about what umount -l might be leaving
>>> behind?  (eg, any unfreed kernel resources)  Or is that a reasonable
>>> way to deal with this situation on an ongoing basis?
>>>
>>> On 8/12/10 08:55 , K. Richard Pixley wrote:
>>>> I'm running into a situation where I can't unmount a mounted
>>>> snapshot.  It shows "busy" even though neither lsof nor fuser show
>>>> any open files.  Umount -f doesn't work although umount -l does.
>>>>
>>>> Is there anything else I can do to debug this scenario or to clear
>>>> the busy status myself?  Or am I down to rebooting each time?
>>>>
>>>> This is on stock ubuntu-10.04, x86.
>> You are lazy unmounting, as I understand, you are essentially just
>> hiding the fact that the mount was busy to userspace... The mount
>> will
>> remain active in the kernel until you resolve whatever was stopping
>> umount in the first place; kernel will then silently unmount.
> Understood.
>> Does this affect all of your mounted snapshots, or only a particular
>> one?
> I'm only mounting one at a time so I haven't noticed.  Will check
> next time it occurs.

More than likely it's just an open app stopping the mount; make sure
any GUI stuff isn't looking at the drive, and no terminals are
either.  I thought that stuff shows up in lsof, but I swear there are
cases when things won't.

C Anthony [mobile]