[Samba] mount.cifs: regular freezes with s3fs

[Matthieu Patou]

On 10/19/2012 03:39 AM, steve wrote:
> On 19/10/12 00:37, Matthieu Patou wrote:
>> On 10/18/2012 11:11 AM, steve wrote:
>>> On 18/10/12 19:52, Jeff Layton wrote:
>>>> On Thu, 18 Oct 2012 18:34:07 +0200
>>>> steve <steve at steve-ss.com> wrote:
>>>>
>
>>> Hi
>>> I'm sure it's not a kernel issue:
>>>
>>> S4 DC, s3fs file server (s3fs on the DC), kernel 3.4.6 -> Freezes
>>> S4 DC, 3.6.3 file server, kernel 3.2.0 -> works fine
>>> S4 DC, 3.6.7 file server, kernel 3.4.6, -> works fine
>>>
>>> Summary: with a separate Samba 3 file server, the same kernel which
>>> gives freezes under s3fs, works correctly.
>> Compare apple and apple, are you using the same configuration in 3.6.7
>> than the one in s3fs (that is generated by Samba AD DC), most 
>> probably not.
>> Can you try two tracks:
>>
>> 1) try to make your samba 3.6.7 config looks like the one of s3fs,
>> please note that some defaults have changed in s3fs like vfs_objects
>> that force the use of acl_xattr, also you have to pay attention if there
>> is folder/files in the share that you serve that are owned by
>> users/group of the domain in both cases as you might in one case kick
>> winbindd calls for each and every sid that you have and the other case
>> you won't.
>>
>> 2) try to use a newer kernel with current s3fs to see if it resolves the
>> problem.
>>
>> Matthieu.
>>
>>
>
> Hi
> 2) seems easier so I installed the 3.6.0 kernel on the client.
>
> there are still long periods where the session freezes. Samba outputs 
> this:
> /usr/local/samba/sbin/smbd: Oplock break failed for file 
> home/steve2/.cache/openbox/openbox.log -- replying anyway
> Here is the trace:
> https://dl.dropbox.com/u/45150875/cifs-freeze3
>
> Re 1)
> -Removing acl_xattr makes no difference.
 From ? s3fs ? in fact I was more suggesting to activate it in your 
samba 3.6.7
> -All users who access the share are domain users belonging to the 
> Domain Users group.
So you have only 1 ACE (Access Control Entry) that give rights to the 
Domain user ?
> -To compare apples I would need to sync sysvol to the S3 fileserver 
> and leave just the global section in smb.conf on the DC. Yes?
No in order to compare apple with apple you need to setup things in the 
same way so for instance you create a share both in your Samba 4.0rx DC 
and the same one in samba 3.6.7,
in both you activate acl_xattr, in both you mount the filesystem where 
the share is pointing to with acl,xattr, in both you set the same ACL 
from windows.
> -Will s3fs be able to work better serving cifs at a later date? Maybe 
> this part of it has not been addressed yet.
S3FS is the same fileserver engine as Samba 3.6.7 we have a couple of 
changes but in theory not such that should generate such regression, 
what I'm much more suspecting is the embedded winbindd in the AD DC that 
is very very different from the one in 3.6.7 or the standalone one in 
current samba 4.0rc.
I don't know if you are fully aware of it but the fileserver will 
ultimately do file access with a given unix user (well a given unix uid) 
and fileserver rely on winbindd to resolve windows SIDs to uid/gid in 
order to check the access rights.ca
It could be possible that on complicated ACL (and sysvol ACL are quite 
complicated) internal winbindd is slower causing the fileserver to be 
slower and ultimately causing the client to look unresponsive.
> - Perhaps at the moment the best way to do this is to have a S3 VM on 
> the DC to do the file and print serving.
That's a good plan B.

Matthieu.
>


-- 
Matthieu Patou
Samba Team
http://samba.org