jffs2: Dynamically choose inocache hash size

When JFFS2 is used for large volumes, the mount times are quite long.
Increasing the hash size provides a significant speed boost on the OLPC
XO-1 laptop.

Add logic that dynamically selects a hash size based on the size of
the medium. A 64mb medium will result in a hash size of 128, and a 512mb
medium will result in a hash size of 1024.

Signed-off-by: Daniel Drake <dsd@laptop.org>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

diff --cc fs/jffs2/build.c
Simple merge

diff --cc fs/jffs2/fs.c
Simple merge

diff --cc fs/jffs2/jffs2_fs_sb.h
Simple merge

diff --cc fs/jffs2/nodelist.c
Simple merge

diff --cc fs/jffs2/nodelist.h
Simple merge