I sent this patch once before for 2.4 kernels, here is the version for 
2.6.8.1.

This patch fixes the problem that huge inode cache
can make invalidate_inodes() calls very long. Meanwhile
lock_kernel() and inode_lock are being held and the system
can freeze for seconds.
I detected this problem on kernel with 4gb split. When inode cache
was 2.5Gb (1,000,000 of inodes in cache) it took seconds to umount
or turn quota off.

So this patch introduces per-super block inode list which makes
possible to scan sb's only inodes when doing umount.

Signed-Off-By: Kirill Korotaev <dev@sw.ru>

Kirill