[Samba] renaming over to a busy file: traces

[Michael Tokarev]

So, what I did:

1. Mount samba share on windows
2. Mount the same samba share on linux (over localhost) on /mnt
3. Started an executable on windows (xml_upload.exe), so
    that this file is busy/locked on the samba side.
4. Raised debugging to 8 and started tcpdump
5. On linux, did a plain mv:
      mv /mnt/.rel/ekis0/xml_upload.exe.1 /mnt/.rel/ekis0/xml_upload.exe
6. stopped tcpdump and lowered debugging to 1.

This succeeded, despite /mnt/.rel/ekis0/xml_upload.exe is running on
windows client (from the same samba server) and is locked on samba
side, so it should fail.

The traces attached are from the operation #5.

Before someone else tells me I should not touch files on linux server
while they're used by samba: I AM NOT TOUCHING FILES BEHIND SAMBA'S BACK.
I'm touching them THROUGH samba, by MOUNTING the *SAMBA* share on linux
and using that mount.  Once again: I do it on linux THROUGH samba, NOT
behind samba.

It looks to me that while renaming a file, samba checks only if the SOURCE
file is locked, but not if the DESTINATION file is locked.

While at it, I also noticed another interesting tidbit, with removals:

1. Start the executable on windows
2. rm that executable file on linux (MOUNTED THROUGH SAMBA again).
    the rm will hang.
3. Cancel the rm (hit Ctrl+C)
4. stop the executable on windows (started in 1.)
5. Notice the file is gone, despite the rm has been interrupted.

Another, more interesting scenario:

1. Start the executable in windows.
2. rm the executable on linux (though samba!!!)
    the rm will hang
3. interrupt the rm
4. rename some other file with this name (which succeeds)
5. stop the executable on windows (started in 1.)
6. notice the file is gone, despite it is now the NEW file already, --
    here, we have obvious data loss.

All this look Seriously Wrong (tm).

Thanks,

/mjt