samba - Jul 2004 - locks cooperating with a server side process

Good day folks,

I'm using Samba 2.2.8a [1] on Slackware 9.1  with 2000/XP clients.

I'm attempting to have a process by which a user drags a file using
Windows Explorer into a share.  On the server side, I have a unix
process that polls the directory for new files and then reads them and
deletes them.

I'm having a problem where I can gain the lock but the process is
still writing to the file.

Python code:
      import fcntl
      # open file in rw so I gain exclusive lock
      f = open("cygwin.tar","r+")
      # if this doesn't raise an IOError, the lock is acquired
      fcntl.lockf(f,fcntl.LOCK_EX|fcntl.LOCK_NB)

which maps into a fcntl exclusive lock with 0 as the start,
end, and whence arguments in the flock structure.

In smb.conf, "locking = yes" had no effect on my process.  The next
thing I tried was "strict locking = yes".  This had the effect that
as soon as my code performs the lock, a windows dialog appears:

   ``Cannot copy cygwin: The process cannot access the file because
   another process has locked a portion of the file''

This leads me to suspect that either Windows Explorer or samba doesn't
gain a lock on the file on creation.  Is there a way to tell samba to
set that lock?

Thanks,
Chris

Footnotes: 
[1]  Samba is compiled:
 --with-fhs \
  --prefix=/usr \
  --localstatedir=/var \
  --bindir=/usr/bin \
  --sbindir=/usr/sbin \
  --with-lockdir=/var/cache/samba \
  --sysconfdir=/etc \
  --with-configdir=/etc/samba \
  --with-privatedir=/etc/samba/private \
  --with-codepagedir=/etc/codepages \
  --with-smbmount \
  --with-quotas \
  --with-syslog \
  --with-utmp \
  --with-sambabook=/usr/share/swat/using_samba \
  --with-ssl \
  --with-sslinc=/usr/include/openssl \
  --with-ssllib=/usr \
  --with-msdfs \
  --with-vfs \
  --with-libsmbclient \
  i386-slackware-linux
-- 
Chris Green <cmg@dok.org>
To err is human, to moo bovine.

Chris Green <cmg@dok.org> writes:
> I'm having a problem where I can gain the lock but the process is
> still writing to the file.
OK, I realized that putting python in might have scared away anyone
that knew C enough to help me out on my problem so I wrote a tiny
util to look at the fcntl based locks.

http://cmg.dok.org/code/lockview.c

As I copy the file from NT -> Linux 2.4, There are no locks set on the
file. However, if I turn strict locking on, posix.c/is_posix_locked
will return true as soon as I gain the lock and abort the copy.

If just plain locking is on, the file will be deleted as soon as the
copy is complete if another process has gained a write lock.


Does anyone else use samba as a drop box for a unix process?

Is there anyway to make a file be locked upon creation with the copy
command?  I have a hard time figuring out all the paramters for
open_file_shared1

[2004/07/20 13:21:37, 5] smbd/files.c:file_new(123)
  allocated file structure 5634, fnum = 9730 (2 used)
[2004/07/20 13:21:37, 10] smbd/open.c:open_file_shared1(807)
  open_file_shared: fname = output/Testing/cygwin.tar, share_mode = 11, ofun =
10, mode = 660, oplock request
= 3


Thanks,
Chris
-- 
Chris Green <cmg@dok.org>
Eschew obfuscation.

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Chris Green wrote:

...

| Does anyone else use samba as a drop box for a unix process?
|
| Is there anyway to make a file be locked upon creation with the copy
| command?  I have a hard time figuring out all the paramters for
| open_file_shared1


Chris,

This kind og question is probably better suited for
the samba-technical mailing list.  I would repost there.




cheers, jerry
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