Re: is flock broken in 2.4 or 2.5 kernels or what does this mean?

From: J.A. Magallon (jamagallon@able.es)
Date: Tue Jul 23 2002 - 16:44:10 EST


On 2002.07.23 Alan Cox wrote:
>On Tue, 2002-07-23 at 15:41, John Covici wrote:
>> In the latest release notes of sendmail I have read the following:
>>
>> NOTE: Linux appears to have broken flock() again. Unless
>> the bug is fixed before sendmail 8.13 is shipped,
>> 8.13 will change the default locking method to
>> fcntl() for Linux kernel 2.4 and later. You may
>> want to do this in 8.12 by compiling with
>> -DHASFLOCK=0. Be sure to update other sendmail
>> related programs to match locking techniques.
>>
>> Can anyone tell me what this is all about -- is there any basis in
>> reality for what they are saying?
>
>First I've heard of it, so it would be useful if someone has access to
>the sendmail problem report/test in question that shows it and I'll go
>find out.
>

Perhaps if you have your spool over nfs:

man flock:

NOTES
       flock(2) does not lock files over NFS. Use fcntl(2)
       instead: that does work over NFS, given a sufficiently
       recent version of Linux and a server which supports lock­
       ing.

       flock(2) and fcntl(2) locks have different semantics with
       respect to forked processes and dup(2).

-- 
J.A. Magallon             \   Software is like sex: It's better when it's free
mailto:jamagallon@able.es  \                    -- Linus Torvalds, FSF T-shirt
Linux werewolf 2.4.19-rc3-jam1, Mandrake Linux 9.0 (Cooker) for i586
gcc (GCC) 3.1.1 (Mandrake Linux 8.3 3.1.1-0.10mdk)
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