Allow file systems supporting ->delete_inode() to call
truncate_inode_pages() on their own.  OCFS2 wants this so it can query the
cluster before making a final decision on whether to wipe an inode from
disk or not.  In some corner cases an inode marked on the local node via
voting may not actually get orphaned.  A good example is node death before
the transaction moving the inode to the orphan dir commits to the journal.
Without this patch, the truncate_inode_pages() call in
generic_delete_inode() would discard valid data for such inodes.

During earlier discussion in the 2.6.13 merge plan thread, Christoph
Hellwig indicated that other file systems might also find this useful.

IMHO, the best solution would be to just allow ->drop_inode() to do the
cluster query but it seems that would require a substantial reworking of
that section of the code.  Assuming it is safe to call write_inode_now() in
ocfs2_delete_inode() for those inodes which won't actually get wiped, this
solution should get us by for now.

Trivial testing of this patch (and a related OCFS2 update) has shown this
to avoid the corruption I'm seeing.

Signed-off-by: Mark Fasheh <mark.fasheh@oracle.com>
Acked-by: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>