ocfs2/dlm: dynamically allocate lvb

Not all dlm_lock_resource/dlm_lock use lvb. It's a waste of memory for those since lvb is a "char lvb[64];".

The following patches try to D-alloc(dynamically allocate) lvb for those which need lvb.

1/5 --D-alloc for dlm_lock_resources.
2/5 ~ 5/5
--D-alloc for dlm_lock.
2/5 --add "struct dlm_lock_resource *res" parameter to dlm_new_lock() so that
we can know if we need to allocates lvb for the dlm_lock.

3/5  --add some assertions on lksb->lvb
4/5  --Copies lvb from lksb only when it's meaningful(not NULL).
5/5  --This is a fat patch. I failed to separate it into parts. I does the main

work for D-alloc for dlm_lock.

For effect of D-alloc lvb for dlm_lock,

without the patch,
[wwg at desk ~]$ egrep "ocfs2_inode" /proc/slabinfo
ocfs2_inode_cache 26 26 1216 26 8 : tunables 0 0 0 : slabdata 1 1 0

with the patch,
[wwg at cool linux-2.6]$ egrep "ocfs2_inode" /proc/slabinfo
ocfs2_inode_cache 32 32 1024 16 4 : tunables 0 0 0 : slabdata 2 2 0

#that result is for i686.

For allocated dlm_lock, there is a memory save too.

regards,
wengang.