To: linux-fsdevel@vger.rutgers.edu
Subject: Ext2 / VFS projects
From: Matthew Wilcox <willy@linuxcare.com>
Date:   Wed, 09 Feb 2000 11:31:03 -0500


Greetings.  Ted Ts'o recently hosted an ext2 puffinfest where we
discussed the future of the VFS and ext2.  Ben LaHaise, Phil Schwan,
Al Viro and Matthew Wilcox were in attendence.  Much pizza was consumed.
We came up with the following list of projects or things to investigate.
Some of them solve similar problems in very different ways so they're
not all worth pursuing.  In particular moving to huge blocks seems to
obviate some of the harder things like managing free space via btrees.
Some of this is rather terse for those who weren't there, feel free to
ask questions.

Some interesting projects for ext2:

2.4:
Collapsed indirect blocks [readonly] (willy)

2.5:
Journalling (sct)
Access to lownumbered inodes
Dynamic inode tables (phil)
Btree directories (phil)
ext2 allocation page size greater than cpu page size (bcrl)
256k blocks with 1k fragments (viro)
	[also 8k blocks with 256-byte fragments!]
Backup inode table
256-byte inodes
 ? Grow block counts to 64 bits
fine-grained locking
	[remove test_and_set_bit()]
e2compr
 ? undelete
nounlink attribute flag
powerdown testing
investigate track-to-track vs long-distance seek times
capabilities
ACLs
Online defragmentation & resize
remove block descriptors
delayed allocation
truncate as an allocation hint on directories too


Some interesting mm/fs projects:

2.4:
Move directories to page cache (bcrl)
Address spaces (viro)
Move fhandle <-> dentry conversion functions to VFS (viro)
move silly_rename to VFS (viro)
Investigate buddy allocator algorithms with more interesting properties (bcrl)
bdflush may need tuning (bcrl)

2.5:
Removal of buffer heads (bcrl)
fix posix fcntl locks (willy)
sort out interface to block devices (viro)
chflags moves to vfs