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Diffstat (limited to 'cpukit/libfs/src/rfs/rtems-rfs-block.h')
| -rw-r--r-- | cpukit/libfs/src/rfs/rtems-rfs-block.h | 324 |
1 files changed, 324 insertions, 0 deletions
diff --git a/cpukit/libfs/src/rfs/rtems-rfs-block.h b/cpukit/libfs/src/rfs/rtems-rfs-block.h new file mode 100644 index 0000000000..e4e3f95830 --- /dev/null +++ b/cpukit/libfs/src/rfs/rtems-rfs-block.h @@ -0,0 +1,324 @@ +/* + * COPYRIGHT (c) 2010 Chris Johns <chrisj@rtems.org> + * + * The license and distribution terms for this file may be + * found in the file LICENSE in this distribution or at + * http://www.rtems.com/license/LICENSE. + * + * $Id$ + */ +/** + * @file + * + * @ingroup rtems-rfs + * + * RTEMS File Systems Block Management. + * + * These functions manage the blocks used in the file system. + */ + +#if !defined (_RTEMS_RFS_BLOCK_H_) +#define _RTEMS_RFS_BLOCK_H_ + +#include <rtems/rfs/rtems-rfs-block-pos.h> +#include <rtems/rfs/rtems-rfs-buffer.h> +#include <rtems/rfs/rtems-rfs-data.h> +#include <rtems/rfs/rtems-rfs-file-system.h> + +/** + * Get a block number in the media format and return it in the host format. + * + * @param _h The buffer handle of the block. + * @param _b The block number index. + * @return uint32_t The block number. + */ +#define rtems_rfs_block_get_number(_h, _b) \ + ((rtems_rfs_block_no) \ + (rtems_rfs_read_u32 (rtems_rfs_buffer_data (_h) + \ + ((_b) * sizeof (rtems_rfs_block_no))))) + +/** + * Set a block number in the media format given a number in the host format. + * + * @param _h The buffer handle of the block. + * @param _b The block number index, ie the number of block number not the + * buffer offset. + * @param _n The block number. + */ +#define rtems_rfs_block_set_number(_h, _b, _n) \ + do { \ + rtems_rfs_write_u32 (rtems_rfs_buffer_data (_h) + \ + ((_b) * sizeof (rtems_rfs_block_no)), (_n)); \ + rtems_rfs_buffer_mark_dirty (_h); \ + } while (0) + +/** + * A block map manges the block lists that originate from an inode. The inode + * contains a number of block numbers. A block map takes those block numbers + * and manages them. + * + * The blocks cannot have all ones as a block number nor block 0. The block map + * is series of block numbers in a blocks. The size of the map determines the + * way the block numbers are stored. The map uses the following: + * + * @li @e Direct Access, + * @li @e Single Indirect Access, and + * @li @e Double Indirect Access. + * + * Direct access has the blocks numbers in the inode slots. The Single Indirect + * Access has block numbers in the inode slots that pointer to a table of block + * numbers that point to data blocks. The Double Indirect Access has block + * numbers in the inode that point to Single Indirect block tables. + * + * The inode can hold a number of Direct, Single Indirect, and Double Indirect + * block tables. The move from Direct to Single occurs then the block count in + * the map is above the number of slots in the inode. The move from Single to + * Double occurs when the map block count is greated than the block numbers per + * block multipled by the slots in the inode. The move from Single to Double + * occurs when the map block count is over the block numbers per block squared + * multipled by the number of slots in the inode. + * + * The block map can managed files of the follow size verses block size with 5 + * inode slots: + * + * @li 41,943,040 bytes for a 512 byte block size, + * @li 335,544,320 bytes for a 1024 byte block size, + * @li 2,684,354,560 bytes for a 2048 byte block size, and + * @li 21,474,836,480 bytes for a 4096 byte block size. + */ +typedef struct rtems_rfs_block_map_s +{ + /** + * Is the map dirty ? + */ + bool dirty; + + /** + * The inode this map is attached to. + */ + rtems_rfs_inode_handle* inode; + + /** + * The size of the map. + */ + rtems_rfs_block_size size; + + /** + * The block map position. Used to navigate the map when seeking. The find + * call is to a position in the file/directory and is a block number plus + * offset. The block find only needs to locate a block and not worry about + * the offset while a seek can be less than a block size yet move across a + * block boundary. Therefore the position a block map has to maintain must + * include the offset so seeks work. + */ + rtems_rfs_block_pos bpos; + + /** + * The last map block allocated. This is used as the goal when allocating a + * new map block. + */ + rtems_rfs_block_no last_map_block; + + /** + * The last data block allocated. This is used as the goal when allocating a + * new data block. + */ + rtems_rfs_block_no last_data_block; + + /** + * The block map. + */ + uint32_t blocks[RTEMS_RFS_INODE_BLOCKS]; + + /** + * Singly Buffer handle. + */ + rtems_rfs_buffer_handle singly_buffer; + + /** + * Doubly Buffer handle. + */ + rtems_rfs_buffer_handle doubly_buffer; + +} rtems_rfs_block_map; + +/** + * Is the map dirty ? + */ +#define rtems_rfs_block_map_is_dirty(_m) ((_m)->dirty) + +/** + * Return the block count in the map. + */ +#define rtems_rfs_block_map_count(_m) ((_m)->size.count) + +/** + * Return the map's size element. + */ +#define rtems_rfs_block_map_size(_m) (&((_m)->size)) + +/** + * Return the size offset for the map. + */ +#define rtems_rfs_block_map_size_offset(_m) ((_m)->size.offset) + +/** + * Are we at the last block in the map ? + */ +#define rtems_rfs_block_map_last(_m) \ + rtems_rfs_block_pos_last_block (&(_m)->bpos, &(_m)->size) + +/** + * Is the position past the end of the block ? + */ +#define rtems_rfs_block_map_past_end(_m, _p) \ + rtems_rfs_block_pos_past_end (_p, &(_m)->size) + +/** + * Return the current position in the map. + */ +#define rtems_rfs_block_map_pos(_f, _m) \ + rtems_rfs_block_get_pos (_f, &(_m)->bpos) + +/** + * Return the map's current block number. + */ +#define rtems_rfs_block_map_block(_m) ((_m)->bpos.bno) + +/** + * Return the map's current block offset. + */ +#define rtems_rfs_block_map_block_offset(_m) ((_m)->bpos.boff) + +/** + * Set the size offset for the map. The map is tagged as dirty. + * + * @param map Pointer to the open map to set the offset in. + * @param offset The offset to set in the map's size. + */ +static inline void +rtems_rfs_block_map_set_size_offset (rtems_rfs_block_map* map, + rtems_rfs_block_off offset) +{ + map->size.offset = offset; + map->dirty = true; +} + +/** + * Set the map's size. The map is tagged as dirty. + * + * @param map Pointer to the open map to set the offset in. + * @param size The size to set in the map's size. + */ +static inline void +rtems_rfs_block_map_set_size (rtems_rfs_block_map* map, + rtems_rfs_block_size* size) +{ + rtems_rfs_block_copy_size (&map->size, size); + map->dirty = true; +} +/** + * Open a block map. The block map data in the inode is copied into the + * map. The buffer handles are opened. The block position is set to the start + * so a seek of offset 0 will return the first block. + * + * @param fs The file system data. + * @param inode The inode the map belongs to. + * @param map The map that is opened. + * @return int The error number (errno). No error if 0. + */ +int rtems_rfs_block_map_open (rtems_rfs_file_system* fs, + rtems_rfs_inode_handle* inode, + rtems_rfs_block_map* map); + +/** + * Close the map. The buffer handles are closed and any help buffers are + * released. + * + * @param fs The file system data. + * @param map The map that is opened. + * @return int The error number (errno). No error if 0. + */ +int rtems_rfs_block_map_close (rtems_rfs_file_system* fs, + rtems_rfs_block_map* map); + +/** + * Find a block number in the map from the position provided. + * + * @param fs The file system data. + * @param map The map to search. + * @param bpos The block position to find. + * @param block Pointer to place the block in when found. + * @return int The error number (errno). No error if 0. + */ +int rtems_rfs_block_map_find (rtems_rfs_file_system* fs, + rtems_rfs_block_map* map, + rtems_rfs_block_pos* bpos, + rtems_rfs_buffer_block* block); + +/** + * Seek around the map. + * + * @param fs The file system data. + * @param map The map to search. + * @param offset The distance to seek. It is signed. + * @param block Pointer to place the block in when found. + * @retval ENXIO Failed to seek because it is outside the block map. + * @return int The error number (errno). No error if 0. + */ +int rtems_rfs_block_map_seek (rtems_rfs_file_system* fs, + rtems_rfs_block_map* map, + rtems_rfs_pos_rel offset, + rtems_rfs_buffer_block* block); + +/** + * Seek to the next block. + * + * @param fs The file system data. + * @param map The map to search. + * @param block Pointer to place the block in when found. + * @retval ENXIO Failed to seek because it is outside the block map. + * @return int The error number (errno). No error if 0. + */ +int rtems_rfs_block_map_next_block (rtems_rfs_file_system* fs, + rtems_rfs_block_map* map, + rtems_rfs_buffer_block* block); + +/** + * Grow the block map by the specified number of blocks. + * + * @param fs The file system data. + * @param map Pointer to the open map to grow. + * @param blocks The number of blocks to grow the map by. + * @param new_block The first of the blocks allocated to the map. + * @return int The error number (errno). No error if 0. + */ +int rtems_rfs_block_map_grow (rtems_rfs_file_system* fs, + rtems_rfs_block_map* map, + size_t blocks, + rtems_rfs_block_no* new_block); + +/** + * Grow the block map by the specified number of blocks. + * + * @param fs The file system data. + * @param map Pointer to the open map to shrink. + * @param blocks The number of blocks to shrink the map by. If more than the + * number of blocks the map is emptied. + * @return int The error number (errno). No error if 0. + */ +int rtems_rfs_block_map_shrink (rtems_rfs_file_system* fs, + rtems_rfs_block_map* map, + size_t blocks); + +/** + * Free all blocks in the map. + * + * @param fs The file system data. + * @param map Pointer to the open map to free all blocks from. + * @return int The error number (errno). No error if 0. + */ +int rtems_rfs_block_map_free_all (rtems_rfs_file_system* fs, + rtems_rfs_block_map* map); + +#endif |