F16: Kernel bug with USB disks ?

[Terry Barnaby]

On 03/28/2012 12:31 PM, Caterpillar wrote:
> 
> 
> 2012/3/28 Terry Barnaby <terry1 at beam.ltd.uk <mailto:terry1 at beam.ltd.uk>>
> 
>     On 03/26/2012 09:20 PM, J. Randall Owens wrote:
>     > On 03/26/2012 06:05 AM, Terry Barnaby wrote:
>     >> Hi,
>     >>
>     >> I am using the latest F16 kernel: 3.3.0-4.fc16.i686.PAE and am having
>     >> problems with a MicroSD card connected to a USB card reader. This has
>     >> been working fine until recently (at least in F14 on the same hardware).
>     >>
>     >> The problem is that "umount" does not appear to be working correctly.
>     >> I have an ext3 file system on the card. I can mount it, and I can copy
>     >> files to it. However when I use the "umount ..." command it returns
>     >> instantly (should sync the files to the card). The system says the card
>     >> is unmounted (at least it is not listed with mount, df etc).
>     >>
>     >> However if I run sync, there is a lot of disk activity to the card ...
>     >>
>     >> Also if I try and run "mkfs" it says the device in in use ...
>     >> If I mount a blank card it lists the files present on the previous card ...
>     >>
>     >> This sounds like a nasty kernel bug ...
>     >> Anyone else seen this ?
>     >
>     > I thought I'd noticed something like this with 3.2.x kernels also; I
>     > couldn't narrow it down more than that.  In my case, it's a USB external
>     > HDD.  After unmounting, I have an old habit of running 3 syncs in one
>     > line.  And lately, I've noticed that I don't even get that disk activity
>     > until I give it a second trio of syncs, which certainly doesn't seem right.
>     > Let me check right now with 3.3.0-4...  Odd, now I do get the activity
>     > at about the same time as the umount, and no further activity when I
>     > issue the syncs.  Seems to be the opposite of what you've reported.
>     >
>     Kernel 3.2.10-3.fc16.i686.PAE also appears to be broken.
>     This seems really very nasty, does it apply to other disks or just to USB
>     ones ...
>     I have added Bugzilla bug: 806909 for this.
> 
>     https://bugzilla.redhat.com/show_bug.cgi?id=806909
> 
>     Cheers
> 
> 
>     Terry
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> 
> I just commented your bugreport with mine that submitted some months ago
> 
> 
For people following this, it appears that if the cups printer daemon is
running then umount fails on USB disks.

How on earth the cups daemon can affect disk data storage unmounts is
baffling to me. Data storage is sacrosanct, how can the Linux kernel allow
this to happen ?

Cheers


Terry