7-STABLE NFS: fatal: "select lock: Permission denied"

[Marc G. Fournier]

On Mon, 4 Apr 2011, Chuck Swiger wrote:

> On Apr 4, 2011, at 12:14 PM, Marc G. Fournier wrote:
>>> OK-- Cyrus IMAP uses a variant of maildir, so you're relatively safe even if locking is not available.
>>
>> So, just to get this clear ...
>>
>> If I were to boot a diskless station using an NFS backend, then that instance would be prone to corruption since lockd wouldn't work, even though the only processes handling the files on that mount?
>
> If you're running a diskless system using NFS filesystem for storage, 
> and you run stuff that wants to do fcntl/lockf/flock locking, and 
> rpc.lockd isn't available, then yes, there is risk of data corruption. 
> However, Postfix can use .dotfile locking, even if fcntl (etc) locking 
> is broken, and maildir is designed to avoid needing locking the way mbox 
> does:
>
>   http://www.postfix.org/NFS_README.html
>
> rpc.lockd provides locking at the filesystem level.  Locks are performed 
> against file descriptors either for entire files or record-level 
> locking; they are not specific to a single process (indeed, locking 
> would be mostly useless if it was only visible within a single process).

Okay, next question ... if lockd is running, should fcntl locks work?  My 
read of the NFS_README.html above indicates to me that they should ... but 
if that is the case, then it comes back to why doesn't it?

----
Marc G. Fournier                        Hub.Org Hosting Solutions S.A.
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