pnfsblock: merge rw extents

	print_bl_extent(ret);

	return ret;

}

/* Helper function to set_to_rw that initialize a new extent */

static void

_prep_new_extent(struct pnfs_block_extent *new,

		 struct pnfs_block_extent *orig,

		 sector_t offset, sector_t length, int state)

{

	kref_init(&new->be_refcnt);

	/* don't need to INIT_LIST_HEAD(&new->be_node) */

	memcpy(&new->be_devid, &orig->be_devid, sizeof(struct nfs4_deviceid));

	new->be_mdev = orig->be_mdev;

	new->be_f_offset = offset;

	new->be_length = length;

	new->be_v_offset = orig->be_v_offset - orig->be_f_offset + offset;

	new->be_state = state;

	new->be_inval = orig->be_inval;

}

/* Tries to merge be with extent in front of it in list.

 * Frees storage if not used.

 */

static struct pnfs_block_extent *

_front_merge(struct pnfs_block_extent *be, struct list_head *head,

	     struct pnfs_block_extent *storage)

{

	struct pnfs_block_extent *prev;

	if (!storage)

		goto no_merge;

	if (&be->be_node == head || be->be_node.prev == head)

		goto no_merge;

	prev = list_entry(be->be_node.prev, struct pnfs_block_extent, be_node);

	if ((prev->be_f_offset + prev->be_length != be->be_f_offset) ||

	    !extents_consistent(prev, be))

		goto no_merge;

	_prep_new_extent(storage, prev, prev->be_f_offset,

			 prev->be_length + be->be_length, prev->be_state);

	list_replace(&prev->be_node, &storage->be_node);

	bl_put_extent(prev);

	list_del(&be->be_node);

	bl_put_extent(be);

	return storage;

 no_merge:

	kfree(storage);

	return be;

}