F16: Kernel bug with USB disks ?

[Terry Barnaby]

On 03/29/2012 10:44 AM, Terry Barnaby wrote:
> 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
Just a warning to all, this bug is still present.
If the cupsd is running and you "umount" a USB disk, then the disk will not
be properly unmounted and any written data will not have been synced.
A pretty major bug that is still there ...