Hi All,

Here is the patch to support madvise(MADV_FREE) - which frees 
up the given range of pages and truncates the underlying backing 
store. This basically provides "punch hole into file" functionality.
Currently it supports ONLY shmfs/tmpfs - where we have short term 
need. Other filesystems return -ENOSYS.

Yes. This is a *crazy* interface to do it. But this is what
we exactly need for now. Here is the discussion on linux-mm 
(for all the fun discussion and the naming):

http://marc.theaimsgroup.com/?l=linux-mm&m=113078625426989&w=2

Andrew, could you include this in your next -mm release ?
BTW, for completeness - this patch includes reiser4-truncate-inode-
pages-range patch from  your -mm series. If you want me to re-work 
my patch without that, please let me know.

http://www.kernel.org/pub/linux/kernel/people/akpm/patches/2.6/2.6.14-
rc5/2.6.14-rc5-mm1/broken-out/reiser4-truncate_inode_pages_range.patch

I tested with my test cases and Jeff Dike was kind enough to provide
a test case with UML - which found more bugs. I thank Andrea & Hugh
for helping me out heavily :)

Comments ?

Thanks,
Badari