/*
   * Copyright (C) 2012 Red Hat, Inc.
   *
   * This file is released under the GPL.
   */
  
  #ifndef DM_CACHE_METADATA_H
  #define DM_CACHE_METADATA_H
  
  #include "dm-cache-block-types.h"
  #include "dm-cache-policy-internal.h"

  #include "persistent-data/dm-space-map-metadata.h"

  
  /*----------------------------------------------------------------*/

  #define DM_CACHE_METADATA_BLOCK_SIZE DM_SM_METADATA_BLOCK_SIZE

  
  /* FIXME: remove this restriction */
  /*
   * The metadata device is currently limited in size.

   */

  #define DM_CACHE_METADATA_MAX_SECTORS DM_SM_METADATA_MAX_SECTORS

  
  /*
   * A metadata device larger than 16GB triggers a warning.
   */
  #define DM_CACHE_METADATA_MAX_SECTORS_WARNING (16 * (1024 * 1024 * 1024 >> SECTOR_SHIFT))
  
  /*----------------------------------------------------------------*/
  
  /*
   * Ext[234]-style compat feature flags.
   *
   * A new feature which old metadata will still be compatible with should
   * define a DM_CACHE_FEATURE_COMPAT_* flag (rarely useful).
   *
   * A new feature that is not compatible with old code should define a
   * DM_CACHE_FEATURE_INCOMPAT_* flag and guard the relevant code with
   * that flag.
   *
   * A new feature that is not compatible with old code accessing the
   * metadata RDWR should define a DM_CACHE_FEATURE_RO_COMPAT_* flag and
   * guard the relevant code with that flag.
   *
   * As these various flags are defined they should be added to the
   * following masks.
   */

  #define DM_CACHE_FEATURE_COMPAT_SUPP	  0UL
  #define DM_CACHE_FEATURE_COMPAT_RO_SUPP	  0UL
  #define DM_CACHE_FEATURE_INCOMPAT_SUPP	  0UL

  struct dm_cache_metadata;

  /*

   * Reopens or creates a new, empty metadata volume.  Returns an ERR_PTR on
   * failure.  If reopening then features must match.

   */
  struct dm_cache_metadata *dm_cache_metadata_open(struct block_device *bdev,
  						 sector_t data_block_size,
  						 bool may_format_device,

  						 size_t policy_hint_size,
  						 unsigned metadata_version);

  
  void dm_cache_metadata_close(struct dm_cache_metadata *cmd);
  
  /*
   * The metadata needs to know how many cache blocks there are.  We don't
   * care about the origin, assuming the core target is giving us valid
   * origin blocks to map to.
   */
  int dm_cache_resize(struct dm_cache_metadata *cmd, dm_cblock_t new_cache_size);

  int dm_cache_size(struct dm_cache_metadata *cmd, dm_cblock_t *result);

  
  int dm_cache_discard_bitset_resize(struct dm_cache_metadata *cmd,
  				   sector_t discard_block_size,

  				   dm_dblock_t new_nr_entries);

  
  typedef int (*load_discard_fn)(void *context, sector_t discard_block_size,

  			       dm_dblock_t dblock, bool discarded);

  int dm_cache_load_discards(struct dm_cache_metadata *cmd,
  			   load_discard_fn fn, void *context);

  int dm_cache_set_discard(struct dm_cache_metadata *cmd, dm_dblock_t dblock, bool discard);

  
  int dm_cache_remove_mapping(struct dm_cache_metadata *cmd, dm_cblock_t cblock);
  int dm_cache_insert_mapping(struct dm_cache_metadata *cmd, dm_cblock_t cblock, dm_oblock_t oblock);
  int dm_cache_changed_this_transaction(struct dm_cache_metadata *cmd);
  
  typedef int (*load_mapping_fn)(void *context, dm_oblock_t oblock,
  			       dm_cblock_t cblock, bool dirty,
  			       uint32_t hint, bool hint_valid);
  int dm_cache_load_mappings(struct dm_cache_metadata *cmd,

  			   struct dm_cache_policy *policy,

  			   load_mapping_fn fn,
  			   void *context);

  int dm_cache_set_dirty_bits(struct dm_cache_metadata *cmd,
  			    unsigned nr_bits, unsigned long *bits);

  
  struct dm_cache_statistics {
  	uint32_t read_hits;
  	uint32_t read_misses;
  	uint32_t write_hits;
  	uint32_t write_misses;
  };
  
  void dm_cache_metadata_get_stats(struct dm_cache_metadata *cmd,
  				 struct dm_cache_statistics *stats);

  
  /*
   * 'void' because it's no big deal if it fails.
   */

  void dm_cache_metadata_set_stats(struct dm_cache_metadata *cmd,
  				 struct dm_cache_statistics *stats);
  
  int dm_cache_commit(struct dm_cache_metadata *cmd, bool clean_shutdown);
  
  int dm_cache_get_free_metadata_block_count(struct dm_cache_metadata *cmd,
  					   dm_block_t *result);
  
  int dm_cache_get_metadata_dev_size(struct dm_cache_metadata *cmd,
  				   dm_block_t *result);
  
  void dm_cache_dump(struct dm_cache_metadata *cmd);
  
  /*
   * The policy is invited to save a 32bit hint value for every cblock (eg,
   * for a hit count).  These are stored against the policy name.  If
   * policies are changed, then hints will be lost.  If the machine crashes,
   * hints will be lost.
   *
   * The hints are indexed by the cblock, but many policies will not
   * neccessarily have a fast way of accessing efficiently via cblock.  So
   * rather than querying the policy for each cblock, we let it walk its data
   * structures and fill in the hints in whatever order it wishes.
   */

  int dm_cache_write_hints(struct dm_cache_metadata *cmd, struct dm_cache_policy *p);

  /*
   * Query method.  Are all the blocks in the cache clean?
   */
  int dm_cache_metadata_all_clean(struct dm_cache_metadata *cmd, bool *result);

  int dm_cache_metadata_needs_check(struct dm_cache_metadata *cmd, bool *result);

  int dm_cache_metadata_set_needs_check(struct dm_cache_metadata *cmd);
  void dm_cache_metadata_set_read_only(struct dm_cache_metadata *cmd);
  void dm_cache_metadata_set_read_write(struct dm_cache_metadata *cmd);
  int dm_cache_metadata_abort(struct dm_cache_metadata *cmd);

  /*----------------------------------------------------------------*/
  
  #endif /* DM_CACHE_METADATA_H */