Win2K/XP, oplocks, and readahead

[Steven French]

The readahead that the Linux page manager does (see mm/readahead.c) seems
more sensible than what you are seeing with the Windows client - if you are
trying to excercise your server in this way you might try the clients using
the current version of Linux 2.5 kernel mounted with the cifs vfs or smbfs
to your Samba server - this is probably a much more efficient way to
exercise readahead using SMB clients.  The algorithm used by the Linux page
manager for readahead is pretty interesting.   Note (if writebehind is also
being tested) that in the current 2.5 kernel implementation of the cifs vfs
at the moment there is a call missing to flush at oplock break time and
also at sync time (flush is called properly at file close time) but this
should be fixed soon.

Steve French
Senior Software Engineer
Linux Technology Center - IBM Austin
phone: 512-838-2294
email: sfrench at us.ibm.com