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kernel/linux-imx6_3.14.28/drivers/md/persistent-data/dm-space-map-common.h 3.37 KB
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  /*
   * Copyright (C) 2011 Red Hat, Inc.
   *
   * This file is released under the GPL.
   */
  
  #ifndef DM_SPACE_MAP_COMMON_H
  #define DM_SPACE_MAP_COMMON_H
  
  #include "dm-btree.h"
  
  /*----------------------------------------------------------------*/
  
  /*
   * Low level disk format
   *
   * Bitmap btree
   * ------------
   *
   * Each value stored in the btree is an index_entry.  This points to a
   * block that is used as a bitmap.  Within the bitmap hold 2 bits per
   * entry, which represent UNUSED = 0, REF_COUNT = 1, REF_COUNT = 2 and
   * REF_COUNT = many.
   *
   * Refcount btree
   * --------------
   *
   * Any entry that has a ref count higher than 2 gets entered in the ref
   * count tree.  The leaf values for this tree is the 32-bit ref count.
   */
  
  struct disk_index_entry {
  	__le64 blocknr;
  	__le32 nr_free;
  	__le32 none_free_before;
  } __packed;
  
  
  #define MAX_METADATA_BITMAPS 255
  struct disk_metadata_index {
  	__le32 csum;
  	__le32 padding;
  	__le64 blocknr;
  
  	struct disk_index_entry index[MAX_METADATA_BITMAPS];
  } __packed;
  
  struct ll_disk;
  
  typedef int (*load_ie_fn)(struct ll_disk *ll, dm_block_t index, struct disk_index_entry *result);
  typedef int (*save_ie_fn)(struct ll_disk *ll, dm_block_t index, struct disk_index_entry *ie);
  typedef int (*init_index_fn)(struct ll_disk *ll);
  typedef int (*open_index_fn)(struct ll_disk *ll);
  typedef dm_block_t (*max_index_entries_fn)(struct ll_disk *ll);
  typedef int (*commit_fn)(struct ll_disk *ll);
  
  struct ll_disk {
  	struct dm_transaction_manager *tm;
  	struct dm_btree_info bitmap_info;
  	struct dm_btree_info ref_count_info;
  
  	uint32_t block_size;
  	uint32_t entries_per_block;
  	dm_block_t nr_blocks;
  	dm_block_t nr_allocated;
  
  	/*
  	 * bitmap_root may be a btree root or a simple index.
  	 */
  	dm_block_t bitmap_root;
  
  	dm_block_t ref_count_root;
  
  	struct disk_metadata_index mi_le;
  	load_ie_fn load_ie;
  	save_ie_fn save_ie;
  	init_index_fn init_index;
  	open_index_fn open_index;
  	max_index_entries_fn max_entries;
  	commit_fn commit;
  	bool bitmap_index_changed:1;
  };
  
  struct disk_sm_root {
  	__le64 nr_blocks;
  	__le64 nr_allocated;
  	__le64 bitmap_root;
  	__le64 ref_count_root;
  } __packed;
  
  #define ENTRIES_PER_BYTE 4
  
  struct disk_bitmap_header {
  	__le32 csum;
  	__le32 not_used;
  	__le64 blocknr;
  } __packed;
  
  enum allocation_event {
  	SM_NONE,
  	SM_ALLOC,
  	SM_FREE,
  };
  
  /*----------------------------------------------------------------*/
  
  int sm_ll_extend(struct ll_disk *ll, dm_block_t extra_blocks);
  int sm_ll_lookup_bitmap(struct ll_disk *ll, dm_block_t b, uint32_t *result);
  int sm_ll_lookup(struct ll_disk *ll, dm_block_t b, uint32_t *result);
  int sm_ll_find_free_block(struct ll_disk *ll, dm_block_t begin,
  			  dm_block_t end, dm_block_t *result);
  int sm_ll_insert(struct ll_disk *ll, dm_block_t b, uint32_t ref_count, enum allocation_event *ev);
  int sm_ll_inc(struct ll_disk *ll, dm_block_t b, enum allocation_event *ev);
  int sm_ll_dec(struct ll_disk *ll, dm_block_t b, enum allocation_event *ev);
  int sm_ll_commit(struct ll_disk *ll);
  
  int sm_ll_new_metadata(struct ll_disk *ll, struct dm_transaction_manager *tm);
  int sm_ll_open_metadata(struct ll_disk *ll, struct dm_transaction_manager *tm,
  			void *root_le, size_t len);
  
  int sm_ll_new_disk(struct ll_disk *ll, struct dm_transaction_manager *tm);
  int sm_ll_open_disk(struct ll_disk *ll, struct dm_transaction_manager *tm,
  		    void *root_le, size_t len);
  
  /*----------------------------------------------------------------*/
  
  #endif	/* DM_SPACE_MAP_COMMON_H */