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

[J.A. Magallon]

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:[e-mail]  \                    -- Linus Torvalds, FSF T-shirt
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