Occassional "permission denied" in the middle of a large transfer over NFS

[Vincent Hoffman]

On 09/07/2012 02:08, Rick Macklem wrote:
> Vincent Hoffman:
>> On 08/07/2012 00:26, Rick Macklem wrote:
>>> Vincent Hoffman wrote:
>>>> Hi Rick,
>>>>
>>>> I'm afraid this didnt make any real difference for me.
>>>> Since I couldnt test it on the live system I tried it on a test vm.
>>>> on the vm (nfs server) I set a looping mount/umount
>>>> while true ; do mount /dev/md0 /mnt/tmp ; sleep 1 ; umount /mnt/tmp
>>>> ;
>>>> done
>>>>
>>>> and on the client I set a loop of tars of large directorys to the
>>>> nfs
>>>> mount running under time to see how well it survived. Then
>>>> replicated
>>>> the test with the patch and without.
>>>>
>>> Just to confirm, you patched both the kernel and mountd and replaced
>>> both
>>> on the server?
>>>
>>> Also, I'm not sure how ZFS handles it's exports. I can't remember if
>>> you've
>>> tried an exported UFS volume. It might be something ZFS specific?
>>>
>>> rick
>> Hi Rick,
>>
>> yes I patched both the kernel and mountd, rebuilt kernel and world (to
>> be sure), added the -S flag to mountd in rc.conf and rebooted.
>> This is a test VM running -CURRENT and is only exporting a ufs2
>> filesystem.
>> (11:43:05 <~>) 0 $ cat /etc/exports
>> /usr/local/export -maproot=root -alldirs XX.XX.XX.XX
>>
>> Client is a 8.3-RELEASE box but I see the same with linux clients.
>> (I can confirm that it works fine when I am not running the
>> mount/umount
>> loop)
>>
> Oops, the patch I sent you worked for NFSv4 only. If you also apply the
> attached patch, it seems to work for NFSv3 as well.
> The patch is also at:
>   http://people.freebsd.org/~rmacklem/atomic-export2.patch
>
> You must also run the new/experimental server. (I can't remember if I
> mentioned that before.)
>
> rick

Hi Rick,
            Just wanted to report that this fixed the "permission
denied" error for my (not terribly exhaustive) testing.
I could transfer all 10G of data by tar to the nfs mount without issue.
I'll try running that a couple more times to be sure but given it was
bombing out in seconds before i'm happy :)

Vince