It also occured to me this would be a good opportunity to work on
adding dirty page support to the page cache code and I have done that
as well.
The quick synopsis of what I have written is as follows:
A complete filesystem that resides in swap, and for kicks and reduced
space consumption uses a btree for all of it's directories.
A patch to allow sync to sync mmaped files, as well as everything else.
A patch to allow the page cache to handle dirty files
A patch to allow the swapoff to work with swap pages that do not
reside in page tables.
SYSV shared memory probably should be modified to work with this.
This is an alpha release. The filesystem is fully functional. But
has some races. Extra eyes, and testers welcome.
My code is at:
http://www.npwt.net/~ebiederm/files/shmfs-0.1.004.tgz
All of this is against kernel 2.1.78.
My goal is to start the discussion of how to get my patches into a
mainstream kernel.
Eric