/* SPDX-License-Identifier: GPL-2.0 */
  
  #ifndef BTRFS_BLOCK_GROUP_H
  #define BTRFS_BLOCK_GROUP_H

  #include "free-space-cache.h"

  enum btrfs_disk_cache_state {
  	BTRFS_DC_WRITTEN,
  	BTRFS_DC_ERROR,
  	BTRFS_DC_CLEAR,
  	BTRFS_DC_SETUP,
  };

  /*

   * This describes the state of the block_group for async discard.  This is due
   * to the two pass nature of it where extent discarding is prioritized over
   * bitmap discarding.  BTRFS_DISCARD_RESET_CURSOR is set when we are resetting
   * between lists to prevent contention for discard state variables
   * (eg. discard_cursor).
   */
  enum btrfs_discard_state {
  	BTRFS_DISCARD_EXTENTS,
  	BTRFS_DISCARD_BITMAPS,
  	BTRFS_DISCARD_RESET_CURSOR,
  };
  
  /*

   * Control flags for do_chunk_alloc's force field CHUNK_ALLOC_NO_FORCE means to
   * only allocate a chunk if we really need one.
   *
   * CHUNK_ALLOC_LIMITED means to only try and allocate one if we have very few
   * chunks already allocated.  This is used as part of the clustering code to
   * help make sure we have a good pool of storage to cluster in, without filling
   * the FS with empty chunks
   *
   * CHUNK_ALLOC_FORCE means it must try to allocate one
   */
  enum btrfs_chunk_alloc_enum {
  	CHUNK_ALLOC_NO_FORCE,
  	CHUNK_ALLOC_LIMITED,
  	CHUNK_ALLOC_FORCE,
  };

  struct btrfs_caching_control {
  	struct list_head list;
  	struct mutex mutex;
  	wait_queue_head_t wait;
  	struct btrfs_work work;

  	struct btrfs_block_group *block_group;

  	u64 progress;
  	refcount_t count;
  };
  
  /* Once caching_thread() finds this much free space, it will wake up waiters. */
  #define CACHING_CTL_WAKE_UP SZ_2M

  struct btrfs_block_group {

  	struct btrfs_fs_info *fs_info;
  	struct inode *inode;
  	spinlock_t lock;

  	u64 start;
  	u64 length;

  	u64 pinned;
  	u64 reserved;

  	u64 used;

  	u64 delalloc_bytes;
  	u64 bytes_super;
  	u64 flags;
  	u64 cache_generation;
  
  	/*
  	 * If the free space extent count exceeds this number, convert the block
  	 * group to bitmaps.
  	 */
  	u32 bitmap_high_thresh;
  
  	/*
  	 * If the free space extent count drops below this number, convert the
  	 * block group back to extents.
  	 */
  	u32 bitmap_low_thresh;
  
  	/*
  	 * It is just used for the delayed data space allocation because
  	 * only the data space allocation and the relative metadata update
  	 * can be done cross the transaction.
  	 */
  	struct rw_semaphore data_rwsem;
  
  	/* For raid56, this is a full stripe, without parity */
  	unsigned long full_stripe_len;
  
  	unsigned int ro;
  	unsigned int iref:1;
  	unsigned int has_caching_ctl:1;
  	unsigned int removed:1;
  
  	int disk_cache_state;
  
  	/* Cache tracking stuff */
  	int cached;
  	struct btrfs_caching_control *caching_ctl;
  	u64 last_byte_to_unpin;
  
  	struct btrfs_space_info *space_info;
  
  	/* Free space cache stuff */
  	struct btrfs_free_space_ctl *free_space_ctl;
  
  	/* Block group cache stuff */
  	struct rb_node cache_node;
  
  	/* For block groups in the same raid type */
  	struct list_head list;

  	refcount_t refs;

  
  	/*
  	 * List of struct btrfs_free_clusters for this block group.
  	 * Today it will only have one thing on it, but that may change
  	 */
  	struct list_head cluster_list;
  
  	/* For delayed block group creation or deletion of empty block groups */
  	struct list_head bg_list;
  
  	/* For read-only block groups */
  	struct list_head ro_list;

  	/*
  	 * When non-zero it means the block group's logical address and its
  	 * device extents can not be reused for future block group allocations
  	 * until the counter goes down to 0. This is to prevent them from being
  	 * reused while some task is still using the block group after it was
  	 * deleted - we want to make sure they can only be reused for new block
  	 * groups after that task is done with the deleted block group.
  	 */
  	atomic_t frozen;

  	/* For discard operations */

  	struct list_head discard_list;
  	int discard_index;
  	u64 discard_eligible_time;

  	u64 discard_cursor;
  	enum btrfs_discard_state discard_state;

  
  	/* For dirty block groups */
  	struct list_head dirty_list;
  	struct list_head io_list;
  
  	struct btrfs_io_ctl io_ctl;
  
  	/*
  	 * Incremented when doing extent allocations and holding a read lock
  	 * on the space_info's groups_sem semaphore.
  	 * Decremented when an ordered extent that represents an IO against this
  	 * block group's range is created (after it's added to its inode's
  	 * root's list of ordered extents) or immediately after the allocation
  	 * if it's a metadata extent or fallocate extent (for these cases we
  	 * don't create ordered extents).
  	 */
  	atomic_t reservations;
  
  	/*
  	 * Incremented while holding the spinlock *lock* by a task checking if
  	 * it can perform a nocow write (incremented if the value for the *ro*
  	 * field is 0). Decremented by such tasks once they create an ordered
  	 * extent or before that if some error happens before reaching that step.
  	 * This is to prevent races between block group relocation and nocow
  	 * writes through direct IO.
  	 */
  	atomic_t nocow_writers;
  
  	/* Lock for free space tree operations. */
  	struct mutex free_space_lock;
  
  	/*
  	 * Does the block group need to be added to the free space tree?
  	 * Protected by free_space_lock.
  	 */
  	int needs_free_space;
  
  	/* Record locked full stripes for RAID5/6 block group */
  	struct btrfs_full_stripe_locks_tree full_stripe_locks_root;
  };

  static inline u64 btrfs_block_group_end(struct btrfs_block_group *block_group)
  {
  	return (block_group->start + block_group->length);
  }

  static inline bool btrfs_is_block_group_data_only(
  					struct btrfs_block_group *block_group)
  {
  	/*
  	 * In mixed mode the fragmentation is expected to be high, lowering the
  	 * efficiency, so only proper data block groups are considered.
  	 */
  	return (block_group->flags & BTRFS_BLOCK_GROUP_DATA) &&
  	       !(block_group->flags & BTRFS_BLOCK_GROUP_METADATA);
  }

  #ifdef CONFIG_BTRFS_DEBUG
  static inline int btrfs_should_fragment_free_space(

  		struct btrfs_block_group *block_group)

  {
  	struct btrfs_fs_info *fs_info = block_group->fs_info;
  
  	return (btrfs_test_opt(fs_info, FRAGMENT_METADATA) &&
  		block_group->flags & BTRFS_BLOCK_GROUP_METADATA) ||
  	       (btrfs_test_opt(fs_info, FRAGMENT_DATA) &&
  		block_group->flags &  BTRFS_BLOCK_GROUP_DATA);
  }
  #endif

  struct btrfs_block_group *btrfs_lookup_first_block_group(

  		struct btrfs_fs_info *info, u64 bytenr);

  struct btrfs_block_group *btrfs_lookup_block_group(

  		struct btrfs_fs_info *info, u64 bytenr);

  struct btrfs_block_group *btrfs_next_block_group(
  		struct btrfs_block_group *cache);
  void btrfs_get_block_group(struct btrfs_block_group *cache);
  void btrfs_put_block_group(struct btrfs_block_group *cache);

  void btrfs_dec_block_group_reservations(struct btrfs_fs_info *fs_info,
  					const u64 start);

  void btrfs_wait_block_group_reservations(struct btrfs_block_group *bg);

  bool btrfs_inc_nocow_writers(struct btrfs_fs_info *fs_info, u64 bytenr);
  void btrfs_dec_nocow_writers(struct btrfs_fs_info *fs_info, u64 bytenr);

  void btrfs_wait_nocow_writers(struct btrfs_block_group *bg);
  void btrfs_wait_block_group_cache_progress(struct btrfs_block_group *cache,

  				           u64 num_bytes);

  int btrfs_wait_block_group_cache_done(struct btrfs_block_group *cache);
  int btrfs_cache_block_group(struct btrfs_block_group *cache,

  			    int load_cache_only);

  void btrfs_put_caching_control(struct btrfs_caching_control *ctl);
  struct btrfs_caching_control *btrfs_get_caching_control(

  		struct btrfs_block_group *cache);
  u64 add_new_free_space(struct btrfs_block_group *block_group,

  		       u64 start, u64 end);

  struct btrfs_trans_handle *btrfs_start_trans_remove_block_group(
  				struct btrfs_fs_info *fs_info,
  				const u64 chunk_offset);
  int btrfs_remove_block_group(struct btrfs_trans_handle *trans,
  			     u64 group_start, struct extent_map *em);
  void btrfs_delete_unused_bgs(struct btrfs_fs_info *fs_info);

  void btrfs_mark_bg_unused(struct btrfs_block_group *bg);

  int btrfs_read_block_groups(struct btrfs_fs_info *info);
  int btrfs_make_block_group(struct btrfs_trans_handle *trans, u64 bytes_used,
  			   u64 type, u64 chunk_offset, u64 size);
  void btrfs_create_pending_block_groups(struct btrfs_trans_handle *trans);

  int btrfs_inc_block_group_ro(struct btrfs_block_group *cache,
  			     bool do_chunk_alloc);

  void btrfs_dec_block_group_ro(struct btrfs_block_group *cache);

  int btrfs_start_dirty_block_groups(struct btrfs_trans_handle *trans);
  int btrfs_write_dirty_block_groups(struct btrfs_trans_handle *trans);
  int btrfs_setup_space_cache(struct btrfs_trans_handle *trans);

  int btrfs_update_block_group(struct btrfs_trans_handle *trans,
  			     u64 bytenr, u64 num_bytes, int alloc);

  int btrfs_add_reserved_bytes(struct btrfs_block_group *cache,

  			     u64 ram_bytes, u64 num_bytes, int delalloc);

  void btrfs_free_reserved_bytes(struct btrfs_block_group *cache,

  			       u64 num_bytes, int delalloc);

  int btrfs_chunk_alloc(struct btrfs_trans_handle *trans, u64 flags,
  		      enum btrfs_chunk_alloc_enum force);
  int btrfs_force_chunk_alloc(struct btrfs_trans_handle *trans, u64 type);
  void check_system_chunk(struct btrfs_trans_handle *trans, const u64 type);

  u64 btrfs_get_alloc_profile(struct btrfs_fs_info *fs_info, u64 orig_flags);

  void btrfs_put_block_group_cache(struct btrfs_fs_info *info);
  int btrfs_free_block_groups(struct btrfs_fs_info *info);

  
  static inline u64 btrfs_data_alloc_profile(struct btrfs_fs_info *fs_info)
  {
  	return btrfs_get_alloc_profile(fs_info, BTRFS_BLOCK_GROUP_DATA);
  }
  
  static inline u64 btrfs_metadata_alloc_profile(struct btrfs_fs_info *fs_info)
  {
  	return btrfs_get_alloc_profile(fs_info, BTRFS_BLOCK_GROUP_METADATA);
  }
  
  static inline u64 btrfs_system_alloc_profile(struct btrfs_fs_info *fs_info)
  {
  	return btrfs_get_alloc_profile(fs_info, BTRFS_BLOCK_GROUP_SYSTEM);
  }

  static inline int btrfs_block_group_done(struct btrfs_block_group *cache)

  {
  	smp_mb();
  	return cache->cached == BTRFS_CACHE_FINISHED ||
  		cache->cached == BTRFS_CACHE_ERROR;
  }

  void btrfs_freeze_block_group(struct btrfs_block_group *cache);
  void btrfs_unfreeze_block_group(struct btrfs_block_group *cache);

  #ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
  int btrfs_rmap_block(struct btrfs_fs_info *fs_info, u64 chunk_start,
  		     u64 physical, u64 **logical, int *naddrs, int *stripe_len);
  #endif

  #endif /* BTRFS_BLOCK_GROUP_H */