/* SPDX-License-Identifier: GPL-2.0+ */

  /*
   * bmap.h - NILFS block mapping.
   *
   * Copyright (C) 2006-2008 Nippon Telegraph and Telephone Corporation.
   *

   * Written by Koji Sato.

   */
  
  #ifndef _NILFS_BMAP_H
  #define _NILFS_BMAP_H
  
  #include <linux/types.h>
  #include <linux/fs.h>
  #include <linux/buffer_head.h>

  #include <linux/nilfs2_ondisk.h>	/* nilfs_binfo, nilfs_inode, etc */

  #include "alloc.h"

  #include "dat.h"

  
  #define NILFS_BMAP_INVALID_PTR	0

  #define nilfs_bmap_keydiff_abs(diff)	((diff) < 0 ? -(diff) : (diff))
  
  
  struct nilfs_bmap;
  
  /**
   * union nilfs_bmap_ptr_req - request for bmap ptr
   * @bpr_ptr: bmap pointer
   * @bpr_req: request for persistent allocator
   */
  union nilfs_bmap_ptr_req {
  	__u64 bpr_ptr;
  	struct nilfs_palloc_req bpr_req;
  };
  
  /**
   * struct nilfs_bmap_stats - bmap statistics
   * @bs_nblocks: number of blocks created or deleted
   */
  struct nilfs_bmap_stats {
  	unsigned int bs_nblocks;
  };
  
  /**
   * struct nilfs_bmap_operations - bmap operation table
   */
  struct nilfs_bmap_operations {
  	int (*bop_lookup)(const struct nilfs_bmap *, __u64, int, __u64 *);

  	int (*bop_lookup_contig)(const struct nilfs_bmap *, __u64, __u64 *,

  				 unsigned int);

  	int (*bop_insert)(struct nilfs_bmap *, __u64, __u64);
  	int (*bop_delete)(struct nilfs_bmap *, __u64);
  	void (*bop_clear)(struct nilfs_bmap *);

  	int (*bop_propagate)(struct nilfs_bmap *, struct buffer_head *);

  	void (*bop_lookup_dirty_buffers)(struct nilfs_bmap *,
  					 struct list_head *);
  
  	int (*bop_assign)(struct nilfs_bmap *,
  			  struct buffer_head **,
  			  sector_t,
  			  union nilfs_binfo *);
  	int (*bop_mark)(struct nilfs_bmap *, __u64, int);

  	int (*bop_seek_key)(const struct nilfs_bmap *, __u64, __u64 *);

  	int (*bop_last_key)(const struct nilfs_bmap *, __u64 *);

  
  	/* The following functions are internal use only. */

  	int (*bop_check_insert)(const struct nilfs_bmap *, __u64);
  	int (*bop_check_delete)(struct nilfs_bmap *, __u64);
  	int (*bop_gather_data)(struct nilfs_bmap *, __u64 *, __u64 *, int);
  };

  #define NILFS_BMAP_SIZE		(NILFS_INODE_BMAP_SIZE * sizeof(__le64))
  #define NILFS_BMAP_KEY_BIT	(sizeof(unsigned long) * 8 /* CHAR_BIT */)
  #define NILFS_BMAP_NEW_PTR_INIT	\
  	(1UL << (sizeof(unsigned long) * 8 /* CHAR_BIT */ - 1))
  
  static inline int nilfs_bmap_is_new_ptr(unsigned long ptr)
  {
  	return !!(ptr & NILFS_BMAP_NEW_PTR_INIT);
  }
  
  
  /**
   * struct nilfs_bmap - bmap structure
   * @b_u: raw data
   * @b_sem: semaphore
   * @b_inode: owner of bmap
   * @b_ops: bmap operation table

   * @b_last_allocated_key: last allocated key for data block
   * @b_last_allocated_ptr: last allocated ptr for data block

   * @b_ptr_type: pointer type

   * @b_state: state

   * @b_nchildren_per_block: maximum number of child nodes for non-root nodes

   */
  struct nilfs_bmap {
  	union {
  		__u8 u_flags;
  		__le64 u_data[NILFS_BMAP_SIZE / sizeof(__le64)];
  	} b_u;
  	struct rw_semaphore b_sem;
  	struct inode *b_inode;
  	const struct nilfs_bmap_operations *b_ops;

  	__u64 b_last_allocated_key;
  	__u64 b_last_allocated_ptr;

  	int b_ptr_type;

  	int b_state;

  	__u16 b_nchildren_per_block;

  };

  /* pointer type */
  #define NILFS_BMAP_PTR_P	0	/* physical block number (i.e. LBN) */

  #define NILFS_BMAP_PTR_VS	1	/*
  					 * virtual block number (single
  					 * version)
  					 */
  #define NILFS_BMAP_PTR_VM	2	/*
  					 * virtual block number (has multiple
  					 * versions)
  					 */

  #define NILFS_BMAP_PTR_U	(-1)	/* never perform pointer operations */
  
  #define NILFS_BMAP_USE_VBN(bmap)	((bmap)->b_ptr_type > 0)

  /* state */
  #define NILFS_BMAP_DIRTY	0x00000001

  /**
   * struct nilfs_bmap_store - shadow copy of bmap state
   * @data: cached raw block mapping of on-disk inode
   * @last_allocated_key: cached value of last allocated key for data block
   * @last_allocated_ptr: cached value of last allocated ptr for data block
   * @state: cached value of state field of bmap structure
   */

  struct nilfs_bmap_store {
  	__le64 data[NILFS_BMAP_SIZE / sizeof(__le64)];
  	__u64 last_allocated_key;
  	__u64 last_allocated_ptr;
  	int state;
  };

  
  int nilfs_bmap_test_and_clear_dirty(struct nilfs_bmap *);
  int nilfs_bmap_read(struct nilfs_bmap *, struct nilfs_inode *);
  void nilfs_bmap_write(struct nilfs_bmap *, struct nilfs_inode *);

  int nilfs_bmap_lookup_contig(struct nilfs_bmap *, __u64, __u64 *, unsigned int);

  int nilfs_bmap_insert(struct nilfs_bmap *bmap, __u64 key, unsigned long rec);
  int nilfs_bmap_delete(struct nilfs_bmap *bmap, __u64 key);

  int nilfs_bmap_seek_key(struct nilfs_bmap *bmap, __u64 start, __u64 *keyp);

  int nilfs_bmap_last_key(struct nilfs_bmap *bmap, __u64 *keyp);
  int nilfs_bmap_truncate(struct nilfs_bmap *bmap, __u64 key);

  void nilfs_bmap_clear(struct nilfs_bmap *);
  int nilfs_bmap_propagate(struct nilfs_bmap *, struct buffer_head *);
  void nilfs_bmap_lookup_dirty_buffers(struct nilfs_bmap *, struct list_head *);
  int nilfs_bmap_assign(struct nilfs_bmap *, struct buffer_head **,
  		      unsigned long, union nilfs_binfo *);
  int nilfs_bmap_lookup_at_level(struct nilfs_bmap *, __u64, int, __u64 *);
  int nilfs_bmap_mark(struct nilfs_bmap *, __u64, int);
  
  void nilfs_bmap_init_gc(struct nilfs_bmap *);

  void nilfs_bmap_save(const struct nilfs_bmap *, struct nilfs_bmap_store *);
  void nilfs_bmap_restore(struct nilfs_bmap *, const struct nilfs_bmap_store *);

  static inline int nilfs_bmap_lookup(struct nilfs_bmap *bmap, __u64 key,
  				    __u64 *ptr)
  {
  	return nilfs_bmap_lookup_at_level(bmap, key, 1, ptr);
  }

  /*
   * Internal use only
   */

  struct inode *nilfs_bmap_get_dat(const struct nilfs_bmap *);

  
  static inline int nilfs_bmap_prepare_alloc_ptr(struct nilfs_bmap *bmap,

  					       union nilfs_bmap_ptr_req *req,
  					       struct inode *dat)

  {

  	if (dat)
  		return nilfs_dat_prepare_alloc(dat, &req->bpr_req);

  	/* ignore target ptr */
  	req->bpr_ptr = bmap->b_last_allocated_ptr++;
  	return 0;
  }
  
  static inline void nilfs_bmap_commit_alloc_ptr(struct nilfs_bmap *bmap,

  					       union nilfs_bmap_ptr_req *req,
  					       struct inode *dat)

  {

  	if (dat)
  		nilfs_dat_commit_alloc(dat, &req->bpr_req);

  }
  
  static inline void nilfs_bmap_abort_alloc_ptr(struct nilfs_bmap *bmap,

  					      union nilfs_bmap_ptr_req *req,
  					      struct inode *dat)

  {

  	if (dat)
  		nilfs_dat_abort_alloc(dat, &req->bpr_req);

  	else
  		bmap->b_last_allocated_ptr--;
  }

  static inline int nilfs_bmap_prepare_end_ptr(struct nilfs_bmap *bmap,

  					     union nilfs_bmap_ptr_req *req,
  					     struct inode *dat)

  {

  	return dat ? nilfs_dat_prepare_end(dat, &req->bpr_req) : 0;

  }
  
  static inline void nilfs_bmap_commit_end_ptr(struct nilfs_bmap *bmap,

  					     union nilfs_bmap_ptr_req *req,
  					     struct inode *dat)

  {

  	if (dat)
  		nilfs_dat_commit_end(dat, &req->bpr_req,
  				     bmap->b_ptr_type == NILFS_BMAP_PTR_VS);

  }
  
  static inline void nilfs_bmap_abort_end_ptr(struct nilfs_bmap *bmap,

  					    union nilfs_bmap_ptr_req *req,
  					    struct inode *dat)

  {

  	if (dat)
  		nilfs_dat_abort_end(dat, &req->bpr_req);

  }

  static inline void nilfs_bmap_set_target_v(struct nilfs_bmap *bmap, __u64 key,
  					   __u64 ptr)
  {
  	bmap->b_last_allocated_key = key;
  	bmap->b_last_allocated_ptr = ptr;
  }

  __u64 nilfs_bmap_data_get_key(const struct nilfs_bmap *,
  			      const struct buffer_head *);
  
  __u64 nilfs_bmap_find_target_seq(const struct nilfs_bmap *, __u64);
  __u64 nilfs_bmap_find_target_in_group(const struct nilfs_bmap *);

  /* Assume that bmap semaphore is locked. */
  static inline int nilfs_bmap_dirty(const struct nilfs_bmap *bmap)
  {
  	return !!(bmap->b_state & NILFS_BMAP_DIRTY);
  }
  
  /* Assume that bmap semaphore is locked. */
  static inline void nilfs_bmap_set_dirty(struct nilfs_bmap *bmap)
  {
  	bmap->b_state |= NILFS_BMAP_DIRTY;
  }
  
  /* Assume that bmap semaphore is locked. */
  static inline void nilfs_bmap_clear_dirty(struct nilfs_bmap *bmap)
  {
  	bmap->b_state &= ~NILFS_BMAP_DIRTY;
  }
  
  
  #define NILFS_BMAP_LARGE	0x1
  
  #define NILFS_BMAP_SMALL_LOW	NILFS_DIRECT_KEY_MIN
  #define NILFS_BMAP_SMALL_HIGH	NILFS_DIRECT_KEY_MAX
  #define NILFS_BMAP_LARGE_LOW	NILFS_BTREE_ROOT_NCHILDREN_MAX
  #define NILFS_BMAP_LARGE_HIGH	NILFS_BTREE_KEY_MAX
  
  #endif	/* _NILFS_BMAP_H */