Implement locking around struct ocfs2_refcount_tree.  This protects
all read/write operations on refcount trees.  ocfs2_refcount_tree
has its own lock and its own caching_info, protecting buffers among
multiple nodes.

User must call ocfs2_lock_refcount_tree before his operation on
the tree and unlock it after that.

ocfs2_refcount_trees are referenced by the block number of the
refcount tree root block, So we create an rb-tree on the ocfs2_super
to look them up.
Signed-off-by: NTao Ma <tao.ma@oracle.com>

refcount tree should use its own caching info so that when
we downconvert the refcount tree lock, we can drop all the
cached buffer head.
Signed-off-by: NTao Ma <tao.ma@oracle.com>

refcount tree lock resource is used to protect refcount
tree read/write among multiple nodes.
Signed-off-by: NTao Ma <tao.ma@oracle.com>

In meta downconvert, we need to checkpoint the metadata in an inode.
For refcount tree, we also need it. So abstract the process out.

Signed-off-by: Tao Ma <tao.ma@oracle.com> 

Signed-off-by: NTao Ma <tao.ma@oracle.com>

Add metaecc and journal trigger for ocfs2_refcount_block.
Signed-off-by: NTao Ma <tao.ma@oracle.com>

Signed-off-by: NTao Ma <tao.ma@oracle.com>

With this commit, extent tree operations are divorced from inodes and
rely on ocfs2_caching_info.  Phew!
Signed-off-by: NJoel Becker <joel.becker@oracle.com>

We only allow unwritten extents on data, so the toplevel
ocfs2_mark_extent_written() can use an inode all it wants.  But the
subfunction isn't even using the inode argument.
Signed-off-by: NJoel Becker <joel.becker@oracle.com>

Don't use a struct inode anymore.
Signed-off-by: NJoel Becker <joel.becker@oracle.com>

It already has an extent_tree.
Signed-off-by: NJoel Becker <joel.becker@oracle.com>

One more generic btree function that is isolated from struct inode.
Signed-off-by: NJoel Becker <joel.becker@oracle.com>

One more function that doesn't need a struct inode to pass to its
children.
Signed-off-by: NJoel Becker <joel.becker@oracle.com>

One more function down, no inode in the entire insert-extent chain.
Signed-off-by: NJoel Becker <joel.becker@oracle.com>

ocfs2_insert_extent() wants to insert a record into the extent map if
it's an inode data extent.  But since many btrees can call that
function, let's make it an op on ocfs2_extent_tree.  Other tree types
can leave it empty.
Signed-off-by: NJoel Becker <joel.becker@oracle.com>

It's not using it, so remove it from the parameter list.
Signed-off-by: NJoel Becker <joel.becker@oracle.com>

It already has an ocfs2_extent_tree and doesn't need the inode.
Signed-off-by: NJoel Becker <joel.becker@oracle.com>

We don't want struct inode in generic btree operations.
Signed-off-by: NJoel Becker <joel.becker@oracle.com>

Don't pass the inode in.  We don't want it around for generic btree
operations.
Signed-off-by: NJoel Becker <joel.becker@oracle.com>

They aren't using it, so remove it from their parameter lists.
Signed-off-by: NJoel Becker <joel.becker@oracle.com>

Another on the way to generic btree functions.
Signed-off-by: NJoel Becker <joel.becker@oracle.com>

Give it an ocfs2_extent_tree and it is happy.
Signed-off-by: NJoel Becker <joel.becker@oracle.com>

ocfs2_remove_extent() wants to truncate the extent map if it's
truncating an inode data extent.  But since many btrees can call that
function, let's make it an op on ocfs2_extent_tree.  Other tree types
can leave it empty.
Signed-off-by: NJoel Becker <joel.becker@oracle.com>

It's not using it anymore.  Remove it from the parameter list.
Signed-off-by: NJoel Becker <joel.becker@oracle.com>

ocfs2_grow_branch() not really using it other than to pass it to the
subfunctions ocfs2_shift_tree_depth(), ocfs2_find_branch_target(), and
ocfs2_add_branch().  The first two weren't it either, so they drop the
argument.  ocfs2_add_branch() only passed it to
ocfs2_adjust_rightmost_branch(), which drops the inode argument and uses
the ocfs2_extent_tree as well.

ocfs2_append_rec_to_path() can be take an ocfs2_extent_tree instead of
the inode.  The function ocfs2_adjust_rightmost_records() goes along for
the ride.
Signed-off-by: NJoel Becker <joel.becker@oracle.com>

It's not using it, so remove it from the parameter list.
Signed-off-by: NJoel Becker <joel.becker@oracle.com>

Drop it from the parameters - they already have ocfs2_extent_list.
Signed-off-by: NJoel Becker <joel.becker@oracle.com>

It already gets ocfs2_extent_tree, so we can just use that.  This chains
to the same modification for ocfs2_remove_rightmost_path() and
ocfs2_rotate_rightmost_leaf_left().
Signed-off-by: NJoel Becker <joel.becker@oracle.com>

It already has struct ocfs2_extent_tree, which has the caching info.  So
we don't need to pass it struct inode.
Signed-off-by: NJoel Becker <joel.becker@oracle.com>

It already has struct ocfs2_extent_tree, which has the caching info.  So
we don't need to pass it struct inode.
Signed-off-by: NJoel Becker <joel.becker@oracle.com>

Pass in the extent tree, which is all we need.
Signed-off-by: NJoel Becker <joel.becker@oracle.com>

We don't need struct inode in ocfs2_rotate_tree_right() anymore.
Signed-off-by: NJoel Becker <joel.becker@oracle.com>

We can get to the inode from the caching information.  Other parent
types don't need it.
Signed-off-by: NJoel Becker <joel.becker@oracle.com>

Get rid of the inode argument.  Use extent_tree instead.  This means a
few more functions have to pass an extent_tree around.
Signed-off-by: NJoel Becker <joel.becker@oracle.com>

Pass the ocfs2_extent_list down through ocfs2_rotate_tree_right() and
get rid of struct inode in ocfs2_rotate_subtree_root_right().
Signed-off-by: NJoel Becker <joel.becker@oracle.com>

Completely unused argument.  Get rid of it.
Signed-off-by: NJoel Becker <joel.becker@oracle.com>

ocfs2_unlink_path() doesn't need struct inode, so let's pass it struct
ocfs2_extent_tree.
Signed-off-by: NJoel Becker <joel.becker@oracle.com>

Pass struct ocfs2_extent_tree into ocfs2_create_new_meta_bhs().  It no
longer needs struct inode or ocfs2_super.
Signed-off-by: NJoel Becker <joel.becker@oracle.com>

ocfs2_find_path and ocfs2_find_leaf() walk our btrees, reading extent
blocks.  They need struct ocfs2_caching_info for that, but not struct
inode.
Signed-off-by: NJoel Becker <joel.becker@oracle.com>

extent blocks belong to btrees on more than just inodes, so we want to
pass the ocfs2_caching_info structure directly to
ocfs2_read_extent_block().  A number of places in alloc.c can now drop
struct inode from their argument list.
Signed-off-by: NJoel Becker <joel.becker@oracle.com>