[linux-cifs-client] Reading files while they're growing in size

[a.nielsen at research.uq.edu.au]

Hi all,

Under NFS, if you're reading a remote file at the same time as the file is
being written to from elsewhere (for example, watching a digital TV
recording at the same time as it is being recorded) the read will 'follow'
the file, i.e. if you start playing the file when only one minute of video
has been recorded, you can keep watching it until one minute after the show
has finished recording - i.e. as the file increases in size, NFS is happy to
keep reading from the file until it hits EOF.

Under CIFS/Samba however, if you start watching the file when only one
minute of video has been recorded, playback will stop after one minute -
even if at that instant in time there are now two minutes of video in the
file.  Likewise if you start playback again it will stop after two minutes,
and by that time there will be four minutes of video available - it won't
continue reading from the file if it has grown in size since it was first
opened.

Is this an issue with CIFS 'remembering' what the filesize was when it was
opened, or with Samba doing something like that?  Is there any way around
it?

Thanks,
Adam.