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  1. /*
  2.  * Copyright (c) 2008 Jakub Jermar
  3.  * Copyright (c) 2008 Martin Decky
  4.  * All rights reserved.
  5.  *
  6.  * Redistribution and use in source and binary forms, with or without
  7.  * modification, are permitted provided that the following conditions
  8.  * are met:
  9.  *
  10.  * - Redistributions of source code must retain the above copyright
  11.  *   notice, this list of conditions and the following disclaimer.
  12.  * - Redistributions in binary form must reproduce the above copyright
  13.  *   notice, this list of conditions and the following disclaimer in the
  14.  *   documentation and/or other materials provided with the distribution.
  15.  * - The name of the author may not be used to endorse or promote products
  16.  *   derived from this software without specific prior written permission.
  17.  *
  18.  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  19.  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  20.  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  21.  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  22.  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  23.  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  24.  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  25.  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  26.  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  27.  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  28.  */
  29.  
  30. /** @addtogroup libblock
  31.  * @{
  32.  */
  33. /**
  34.  * @file
  35.  */
  36.  
  37. #ifndef LIBBLOCK_LIBBLOCK_H_
  38. #define LIBBLOCK_LIBBLOCK_H_
  39.  
  40. #include <stdint.h>
  41. #include "../../srv/vfs/vfs.h"
  42. #include <fibril_sync.h>
  43. #include <adt/hash_table.h>
  44. #include <adt/list.h>
  45.  
  46. /*
  47.  * Flags that can be used with block_get().
  48.  */
  49.  
  50. /**
  51.  * This macro is a symbolic value for situations where no special flags are
  52.  * needed.
  53.  */
  54. #define BLOCK_FLAGS_NONE    0
  55.  
  56. /**
  57.  * When the client of block_get() intends to overwrite the current contents of
  58.  * the block, this flag is used to avoid the unnecessary read.
  59.  */
  60. #define BLOCK_FLAGS_NOREAD  1
  61.  
  62. typedef unsigned bn_t;  /**< Block number type. */
  63.  
  64. typedef struct block {
  65.     /** Mutex protecting the reference count. */
  66.     fibril_mutex_t lock;
  67.     /** Number of references to the block_t structure. */
  68.     unsigned refcnt;
  69.     /** If true, the block needs to be written back to the block device. */
  70.     bool dirty;
  71.     /** Readers / Writer lock protecting the contents of the block. */
  72.     fibril_rwlock_t contents_lock;
  73.     /** Handle of the device where the block resides. */
  74.     dev_handle_t dev_handle;
  75.     /** Block offset on the block device. Counted in 'size'-byte blocks. */
  76.     bn_t boff;
  77.     /** Size of the block. */
  78.     size_t size;
  79.     /** Link for placing the block into the free block list. */
  80.     link_t free_link;
  81.     /** Link for placing the block into the block hash table. */
  82.     link_t hash_link;
  83.     /** Buffer with the block data. */
  84.     void *data;
  85. } block_t;
  86.  
  87. /** Caching mode */
  88. enum cache_mode {
  89.     /** Write-Through */
  90.     CACHE_MODE_WT,
  91.     /** Write-Back */
  92.     CACHE_MODE_WB
  93. };
  94.  
  95. extern int block_init(dev_handle_t, size_t);
  96. extern void block_fini(dev_handle_t);
  97.  
  98. extern int block_bb_read(dev_handle_t, off_t, size_t);
  99. extern void *block_bb_get(dev_handle_t);
  100.  
  101. extern int block_cache_init(dev_handle_t, size_t, unsigned, enum cache_mode);
  102.  
  103. extern block_t *block_get(dev_handle_t, bn_t, int);
  104. extern void block_put(block_t *);
  105.  
  106. extern int block_seqread(dev_handle_t, off_t *, size_t *, off_t *, void *,
  107.     size_t, size_t);
  108.  
  109. #endif
  110.  
  111. /** @}
  112.  */
  113.  
  114.