/* -*- mode: c; c-basic-offset: 8; -*-
   * vim: noexpandtab sw=8 ts=8 sts=0:
   *
   * alloc.h
   *
   * Function prototypes
   *
   * Copyright (C) 2002, 2004 Oracle.  All rights reserved.
   *
   * This program is free software; you can redistribute it and/or
   * modify it under the terms of the GNU General Public
   * License as published by the Free Software Foundation; either
   * version 2 of the License, or (at your option) any later version.
   *
   * This program is distributed in the hope that it will be useful,
   * but WITHOUT ANY WARRANTY; without even the implied warranty of
   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   * General Public License for more details.
   *
   * You should have received a copy of the GNU General Public
   * License along with this program; if not, write to the
   * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
   * Boston, MA 021110-1307, USA.
   */
  
  #ifndef OCFS2_ALLOC_H
  #define OCFS2_ALLOC_H
  
  
  /*
   * For xattr tree leaf, we limit the leaf byte size to be 64K.
   */
  #define OCFS2_MAX_XATTR_TREE_LEAF_SIZE 65536
  
  /*
   * ocfs2_extent_tree and ocfs2_extent_tree_operations are used to abstract
   * the b-tree operations in ocfs2. Now all the b-tree operations are not
   * limited to ocfs2_dinode only. Any data which need to allocate clusters
   * to store can use b-tree. And it only needs to implement its ocfs2_extent_tree
   * and operation.
   *
   * ocfs2_extent_tree becomes the first-class object for extent tree
   * manipulation.  Callers of the alloc.c code need to fill it via one of
   * the ocfs2_init_*_extent_tree() operations below.
   *
   * ocfs2_extent_tree contains info for the root of the b-tree, it must have a
   * root ocfs2_extent_list and a root_bh so that they can be used in the b-tree
   * functions.  It needs the ocfs2_caching_info structure associated with
   * I/O on the tree.  With metadata ecc, we now call different journal_access
   * functions for each type of metadata, so it must have the
   * root_journal_access function.
   * ocfs2_extent_tree_operations abstract the normal operations we do for
   * the root of extent b-tree.
   */
  struct ocfs2_extent_tree_operations;
  struct ocfs2_extent_tree {
  	struct ocfs2_extent_tree_operations	*et_ops;
  	struct buffer_head			*et_root_bh;
  	struct ocfs2_extent_list		*et_root_el;
  	struct ocfs2_caching_info		*et_ci;
  	ocfs2_journal_access_func		et_root_journal_access;
  	void					*et_object;
  	unsigned int				et_max_leaf_clusters;
  };
  
  /*
   * ocfs2_init_*_extent_tree() will fill an ocfs2_extent_tree from the
   * specified object buffer.
   */
  void ocfs2_init_dinode_extent_tree(struct ocfs2_extent_tree *et,
  				   struct ocfs2_caching_info *ci,
  				   struct buffer_head *bh);
  void ocfs2_init_xattr_tree_extent_tree(struct ocfs2_extent_tree *et,
  				       struct ocfs2_caching_info *ci,
  				       struct buffer_head *bh);
  struct ocfs2_xattr_value_buf;
  void ocfs2_init_xattr_value_extent_tree(struct ocfs2_extent_tree *et,
  					struct ocfs2_caching_info *ci,
  					struct ocfs2_xattr_value_buf *vb);
  void ocfs2_init_dx_root_extent_tree(struct ocfs2_extent_tree *et,
  				    struct ocfs2_caching_info *ci,
  				    struct buffer_head *bh);
  void ocfs2_init_refcount_extent_tree(struct ocfs2_extent_tree *et,
  				     struct ocfs2_caching_info *ci,
  				     struct buffer_head *bh);
  
  /*
   * Read an extent block into *bh.  If *bh is NULL, a bh will be
   * allocated.  This is a cached read.  The extent block will be validated
   * with ocfs2_validate_extent_block().
   */
  int ocfs2_read_extent_block(struct ocfs2_caching_info *ci, u64 eb_blkno,
  			    struct buffer_head **bh);
  
  struct ocfs2_alloc_context;
  int ocfs2_insert_extent(handle_t *handle,
  			struct ocfs2_extent_tree *et,
  			u32 cpos,
  			u64 start_blk,
  			u32 new_clusters,
  			u8 flags,
  			struct ocfs2_alloc_context *meta_ac);
  
  enum ocfs2_alloc_restarted {
  	RESTART_NONE = 0,
  	RESTART_TRANS,
  	RESTART_META
  };
  int ocfs2_add_clusters_in_btree(handle_t *handle,
  				struct ocfs2_extent_tree *et,
  				u32 *logical_offset,
  				u32 clusters_to_add,
  				int mark_unwritten,
  				struct ocfs2_alloc_context *data_ac,
  				struct ocfs2_alloc_context *meta_ac,
  				enum ocfs2_alloc_restarted *reason_ret);
  struct ocfs2_cached_dealloc_ctxt;
  struct ocfs2_path;
  int ocfs2_split_extent(handle_t *handle,
  		       struct ocfs2_extent_tree *et,
  		       struct ocfs2_path *path,
  		       int split_index,
  		       struct ocfs2_extent_rec *split_rec,
  		       struct ocfs2_alloc_context *meta_ac,
  		       struct ocfs2_cached_dealloc_ctxt *dealloc);
  int ocfs2_mark_extent_written(struct inode *inode,
  			      struct ocfs2_extent_tree *et,
  			      handle_t *handle, u32 cpos, u32 len, u32 phys,
  			      struct ocfs2_alloc_context *meta_ac,
  			      struct ocfs2_cached_dealloc_ctxt *dealloc);
  int ocfs2_change_extent_flag(handle_t *handle,
  			     struct ocfs2_extent_tree *et,
  			     u32 cpos, u32 len, u32 phys,
  			     struct ocfs2_alloc_context *meta_ac,
  			     struct ocfs2_cached_dealloc_ctxt *dealloc,
  			     int new_flags, int clear_flags);
  int ocfs2_remove_extent(handle_t *handle, struct ocfs2_extent_tree *et,
  			u32 cpos, u32 len,
  			struct ocfs2_alloc_context *meta_ac,
  			struct ocfs2_cached_dealloc_ctxt *dealloc);
  int ocfs2_remove_btree_range(struct inode *inode,
  			     struct ocfs2_extent_tree *et,
  			     u32 cpos, u32 phys_cpos, u32 len, int flags,
  			     struct ocfs2_cached_dealloc_ctxt *dealloc,
  			     u64 refcount_loc);
  
  int ocfs2_num_free_extents(struct ocfs2_super *osb,
  			   struct ocfs2_extent_tree *et);
  
  /*
   * how many new metadata chunks would an allocation need at maximum?
   *
   * Please note that the caller must make sure that root_el is the root
   * of extent tree. So for an inode, it should be &fe->id2.i_list. Otherwise
   * the result may be wrong.
   */
  static inline int ocfs2_extend_meta_needed(struct ocfs2_extent_list *root_el)
  {
  	/*
  	 * Rather than do all the work of determining how much we need
  	 * (involves a ton of reads and locks), just ask for the
  	 * maximal limit.  That's a tree depth shift.  So, one block for
  	 * level of the tree (current l_tree_depth), one block for the
  	 * new tree_depth==0 extent_block, and one block at the new
  	 * top-of-the tree.
  	 */
  	return le16_to_cpu(root_el->l_tree_depth) + 2;
  }
  
  void ocfs2_dinode_new_extent_list(struct inode *inode, struct ocfs2_dinode *di);
  void ocfs2_set_inode_data_inline(struct inode *inode, struct ocfs2_dinode *di);
  int ocfs2_convert_inline_data_to_extents(struct inode *inode,
  					 struct buffer_head *di_bh);
  
  int ocfs2_truncate_log_init(struct ocfs2_super *osb);
  void ocfs2_truncate_log_shutdown(struct ocfs2_super *osb);
  void ocfs2_schedule_truncate_log_flush(struct ocfs2_super *osb,
  				       int cancel);
  int ocfs2_flush_truncate_log(struct ocfs2_super *osb);
  int ocfs2_begin_truncate_log_recovery(struct ocfs2_super *osb,
  				      int slot_num,
  				      struct ocfs2_dinode **tl_copy);
  int ocfs2_complete_truncate_log_recovery(struct ocfs2_super *osb,
  					 struct ocfs2_dinode *tl_copy);
  int ocfs2_truncate_log_needs_flush(struct ocfs2_super *osb);
  int ocfs2_truncate_log_append(struct ocfs2_super *osb,
  			      handle_t *handle,
  			      u64 start_blk,
  			      unsigned int num_clusters);
  int __ocfs2_flush_truncate_log(struct ocfs2_super *osb);
  
  /*
   * Process local structure which describes the block unlinks done
   * during an operation. This is populated via
   * ocfs2_cache_block_dealloc().
   *
   * ocfs2_run_deallocs() should be called after the potentially
   * de-allocating routines. No journal handles should be open, and most
   * locks should have been dropped.
   */
  struct ocfs2_cached_dealloc_ctxt {
  	struct ocfs2_per_slot_free_list		*c_first_suballocator;
  	struct ocfs2_cached_block_free 		*c_global_allocator;
  };
  static inline void ocfs2_init_dealloc_ctxt(struct ocfs2_cached_dealloc_ctxt *c)
  {
  	c->c_first_suballocator = NULL;
  	c->c_global_allocator = NULL;
  }
  int ocfs2_cache_cluster_dealloc(struct ocfs2_cached_dealloc_ctxt *ctxt,
  				u64 blkno, unsigned int bit);
  int ocfs2_cache_block_dealloc(struct ocfs2_cached_dealloc_ctxt *ctxt,
  			      int type, int slot, u64 suballoc, u64 blkno,
  			      unsigned int bit);
  static inline int ocfs2_dealloc_has_cluster(struct ocfs2_cached_dealloc_ctxt *c)
  {
  	return c->c_global_allocator != NULL;
  }
  int ocfs2_run_deallocs(struct ocfs2_super *osb,
  		       struct ocfs2_cached_dealloc_ctxt *ctxt);
  
  struct ocfs2_truncate_context {
  	struct ocfs2_cached_dealloc_ctxt tc_dealloc;
  	int tc_ext_alloc_locked; /* is it cluster locked? */
  	/* these get destroyed once it's passed to ocfs2_commit_truncate. */
  	struct buffer_head *tc_last_eb_bh;
  };
  
  int ocfs2_zero_range_for_truncate(struct inode *inode, handle_t *handle,
  				  u64 range_start, u64 range_end);
  int ocfs2_commit_truncate(struct ocfs2_super *osb,
  			  struct inode *inode,
  			  struct buffer_head *di_bh);
  int ocfs2_truncate_inline(struct inode *inode, struct buffer_head *di_bh,
  			  unsigned int start, unsigned int end, int trunc);
  
  int ocfs2_find_leaf(struct ocfs2_caching_info *ci,
  		    struct ocfs2_extent_list *root_el, u32 cpos,
  		    struct buffer_head **leaf_bh);
  int ocfs2_search_extent_list(struct ocfs2_extent_list *el, u32 v_cluster);
  
  int ocfs2_trim_fs(struct super_block *sb, struct fstrim_range *range);
  /*
   * Helper function to look at the # of clusters in an extent record.
   */
  static inline unsigned int ocfs2_rec_clusters(struct ocfs2_extent_list *el,
  					      struct ocfs2_extent_rec *rec)
  {
  	/*
  	 * Cluster count in extent records is slightly different
  	 * between interior nodes and leaf nodes. This is to support
  	 * unwritten extents which need a flags field in leaf node
  	 * records, thus shrinking the available space for a clusters
  	 * field.
  	 */
  	if (el->l_tree_depth)
  		return le32_to_cpu(rec->e_int_clusters);
  	else
  		return le16_to_cpu(rec->e_leaf_clusters);
  }
  
  /*
   * This is only valid for leaf nodes, which are the only ones that can
   * have empty extents anyway.
   */
  static inline int ocfs2_is_empty_extent(struct ocfs2_extent_rec *rec)
  {
  	return !rec->e_leaf_clusters;
  }
  
  int ocfs2_grab_pages(struct inode *inode, loff_t start, loff_t end,
  		     struct page **pages, int *num);
  void ocfs2_map_and_dirty_page(struct inode *inode, handle_t *handle,
  			      unsigned int from, unsigned int to,
  			      struct page *page, int zero, u64 *phys);
  /*
   * Structures which describe a path through a btree, and functions to
   * manipulate them.
   *
   * The idea here is to be as generic as possible with the tree
   * manipulation code.
   */
  struct ocfs2_path_item {
  	struct buffer_head		*bh;
  	struct ocfs2_extent_list	*el;
  };
  
  #define OCFS2_MAX_PATH_DEPTH	5
  
  struct ocfs2_path {
  	int				p_tree_depth;
  	ocfs2_journal_access_func	p_root_access;
  	struct ocfs2_path_item		p_node[OCFS2_MAX_PATH_DEPTH];
  };
  
  #define path_root_bh(_path) ((_path)->p_node[0].bh)
  #define path_root_el(_path) ((_path)->p_node[0].el)
  #define path_root_access(_path)((_path)->p_root_access)
  #define path_leaf_bh(_path) ((_path)->p_node[(_path)->p_tree_depth].bh)
  #define path_leaf_el(_path) ((_path)->p_node[(_path)->p_tree_depth].el)
  #define path_num_items(_path) ((_path)->p_tree_depth + 1)
  
  void ocfs2_reinit_path(struct ocfs2_path *path, int keep_root);
  void ocfs2_free_path(struct ocfs2_path *path);
  int ocfs2_find_path(struct ocfs2_caching_info *ci,
  		    struct ocfs2_path *path,
  		    u32 cpos);
  struct ocfs2_path *ocfs2_new_path_from_path(struct ocfs2_path *path);
  struct ocfs2_path *ocfs2_new_path_from_et(struct ocfs2_extent_tree *et);
  int ocfs2_path_bh_journal_access(handle_t *handle,
  				 struct ocfs2_caching_info *ci,
  				 struct ocfs2_path *path,
  				 int idx);
  int ocfs2_journal_access_path(struct ocfs2_caching_info *ci,
  			      handle_t *handle,
  			      struct ocfs2_path *path);
  int ocfs2_find_cpos_for_right_leaf(struct super_block *sb,
  				   struct ocfs2_path *path, u32 *cpos);
  int ocfs2_find_cpos_for_left_leaf(struct super_block *sb,
  				  struct ocfs2_path *path, u32 *cpos);
  int ocfs2_find_subtree_root(struct ocfs2_extent_tree *et,
  			    struct ocfs2_path *left,
  			    struct ocfs2_path *right);
  #endif /* OCFS2_ALLOC_H */