[Samba] fcntl lock failed at large offset: pretty urgent

[Jeremy Allison]

On Tue, Dec 02, 2003 at 07:47:50PM +1100, Jim Thomas wrote:
> Debian Woody with security updates
> Linux kernel 2.2.25
> Samba 3.0.0
> libc6 2.2.5
> 
> The problem I have is with a windows application that uses samba.  This
> application is crucial for the organization, so if this is not fixed,
> and soon, we will have to ditch Samba and move to a windows server.
> I *really* don't want to do this, as Samba has been working so well for
> years now and billg is rich enough already.
> 
> I am having problems with a windows client program that does a range
> lock on a file on a share.  The log.smbd reports with debug level 3:
> 
> [2003/12/02 17:20:23, 3] lib/util.c:fcntl_lock(1632)
>   fcntl_lock: fcntl lock gave errno 75 (Value too large for defined data type)
> [2003/12/02 17:20:23, 3] lib/util.c:fcntl_lock(1651)
>   fcntl_lock: lock failed at offset 4294967284 count 1 op 13 type 1 (Value too large for defined data type)
> [2003/12/02 17:20:23, 3] smbd/error.c:error_packet(94)
>   error string = Value too large for defined data type
> 
> What I think is happening is the client is passing a number
> greater than 2^31 as the lock range, which will fail according to
> http://samba.org/samba/docs/man/locking.html#id2918968 which states
> that samba locks from 0-2^31, whereas windows issues lock requests up
> to 2^32 or 2^64.
> 
> Setting "locking = no" fixes the problem, but will cause others as these
> files are used by many people at once.

If Samba is configured to use 64 bit filesystems it assumes it
can lock from 0 to 2^63-1 - the code in locking/posix.c in posix_fcntl_lock()
takes care of this. If it is configured to use 32 bit filesystems
it assumes it can lock from 0 to 2^31-1.

Samba will truncate the posix lock above these limits as no posix
application will ever see such a lock. You might get this problem
if you're running a 64-bit Samba gatewaying onto a 32-bit mounted
NFS mount, or other mounted partition.

Can you give more details about the setup please ? This code has been
stable and working for quite a long time now.

Jeremy.