RTEMS File Systems Block RoutinesThese functions manage blocks in the RFS file system. A block is an area of the media and its size is set for a each specific media. The block size is set when the file system is set up and needs to be matched for it to be read correctly. More...

#include <inttypes.h>
#include <string.h>
#include <rtems/rfs/rtems-rfs-block.h>
#include <rtems/rfs/rtems-rfs-data.h>
#include <rtems/rfs/rtems-rfs-group.h>
#include <rtems/rfs/rtems-rfs-inode.h>

Functions
void	rtems_rfs_block_get_bpos (rtems_rfs_file_system fs, rtems_rfs_pos pos, rtems_rfs_block_pos bpos)

rtems_rfs_pos	rtems_rfs_block_get_pos (rtems_rfs_file_system fs, rtems_rfs_block_pos bpos)

void	rtems_rfs_block_get_block_size (rtems_rfs_file_system fs, rtems_rfs_pos pos, rtems_rfs_block_size size)

rtems_rfs_pos	rtems_rfs_block_get_size (rtems_rfs_file_system fs, rtems_rfs_block_size size)

int	rtems_rfs_block_map_open (rtems_rfs_file_system fs, rtems_rfs_inode_handle inode, rtems_rfs_block_map *map)

int	rtems_rfs_block_map_close (rtems_rfs_file_system fs, rtems_rfs_block_map map)

int	rtems_rfs_block_map_find (rtems_rfs_file_system fs, rtems_rfs_block_map map, rtems_rfs_block_pos bpos, rtems_rfs_block_no block)

int	rtems_rfs_block_map_seek (rtems_rfs_file_system fs, rtems_rfs_block_map map, rtems_rfs_pos_rel offset, rtems_rfs_block_no *block)

int	rtems_rfs_block_map_next_block (rtems_rfs_file_system fs, rtems_rfs_block_map map, rtems_rfs_block_no *block)

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)

int	rtems_rfs_block_map_shrink (rtems_rfs_file_system fs, rtems_rfs_block_map map, size_t blocks)

int	rtems_rfs_block_map_free_all (rtems_rfs_file_system fs, rtems_rfs_block_map map)

Detailed Description

RTEMS File Systems Block Routines

These functions manage blocks in the RFS file system. A block is an area of the media and its size is set for a each specific media. The block size is set when the file system is set up and needs to be matched for it to be read correctly.

Blocks are managed as groups. A block group or "group" is part of the total number of blocks being managed by the file system and exist to allow resources to localised. A file in a directory will be allocated blocks in the same group as the directory, and the blocks for the file will also be allocated in the same group.

A group consist of a block bitmap, inodes and data blocks. The first block of the file system will hold the superblock. The block bitmap is a collection of blocks that hold a map of bits, one bit per block for each block in the group. When a file system is mounted the block bitmaps are read and a summary bit map is made. The summary bitmap has a single bit for 32 bits in the bitmap and is set when all 32 bits it maps to are set. This speeds up the search for a free block by a factor of 32.

Function Documentation

◆ rtems_rfs_block_get_block_size()

void rtems_rfs_block_get_block_size	(	rtems_rfs_file_system *	fs,
		rtems_rfs_pos	pos,
		rtems_rfs_block_size *	size
	)

Set the size given a position.

Parameters

[in]	fs	is the file system data.
[in]	pos	is the position as an absolute offset from the start.
[out]	size	is a pointer to the block size to fill in.

◆ rtems_rfs_block_get_bpos()

void rtems_rfs_block_get_bpos	(	rtems_rfs_file_system *	fs,
		rtems_rfs_pos	pos,
		rtems_rfs_block_pos *	bpos
	)

Given a position compute the block number and block offset.

Parameters

[in]	fs	is the file system data.
[in]	pos	is the position as an absolute offset from the start.
[out]	bpos	is a pointer to the block position to fill in.

◆ rtems_rfs_block_get_pos()

rtems_rfs_pos rtems_rfs_block_get_pos	(	rtems_rfs_file_system *	fs,
		rtems_rfs_block_pos *	bpos
	)

Given a block position compute the absolute offset.

Parameters

[in]	fs	is the file system data.
[out]	bpos	is a pointer to the block position to fill in.

Return values

offset The absolute offset.

◆ rtems_rfs_block_get_size()

rtems_rfs_pos rtems_rfs_block_get_size	(	rtems_rfs_file_system *	fs,
		rtems_rfs_block_size *	size
	)

Calculate the position given the number of blocks and the offset. If the block count is 0 the size is 0. If the block is greater than 0 and the offset is 0 the size is number of blocks multipled by the block size and if the offset is not 0 it is the offset into the last block. For example if blocks is 1 and offset is 0 the size is the block size. If the block count is 1 and size is 100 the size is 100.

Parameters

[in]	fs	is the file system data.
[in]	size	The size in blocks and offset.

Return values

size	The size in bytes.

◆ rtems_rfs_block_map_close()

int rtems_rfs_block_map_close	(	rtems_rfs_file_system *	fs,
		rtems_rfs_block_map *	map
	)

Close the map. The buffer handles are closed and any help buffers are released.

Parameters

[in]	fs	is the file system data.
[in]	map	is a pointer to the map that is opened.

Return values

0	Successful operation.
error_code	An error occurred.

◆ rtems_rfs_block_map_find()

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
	)

Find a block number in the map from the position provided.

Parameters

[in]	fs	is the file system data.
[in]	map	is a pointer to the map to search.
[in]	bpos	is a pointer to the block position to find.
[out]	block	will contain the block in when found.

Return values

0	Successful operation.
error_code	An error occurred.

◆ rtems_rfs_block_map_free_all()

int rtems_rfs_block_map_free_all	(	rtems_rfs_file_system *	fs,
		rtems_rfs_block_map *	map
	)

Free all blocks in the map.

Parameters

[in]	fs	is the file system data.
[in]	map	is a pointer to the open map to free all blocks from.

Return values

0	Successful operation.
error_code	An error occurred.

◆ rtems_rfs_block_map_grow()

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.

Parameters

[in]	fs	is the file system data.
[in]	map	is a pointer to the open map to grow.
[in]	blocks	is the number of blocks to grow the map by.
[out]	new_block	will contain first of the blocks allocated to the map.

Return values

0	Successful operation.
error_code	An error occurred.

◆ rtems_rfs_block_map_next_block()

int rtems_rfs_block_map_next_block	(	rtems_rfs_file_system *	fs,
		rtems_rfs_block_map *	map,
		rtems_rfs_buffer_block *	block
	)

Seek to the next block.

Parameters

[in]	fs	is the file system data.
[in]	map	is a pointer to the map to search.
[out]	block	will contain the block in when found.

Return values

0	Successful operation.
ENXIO	Failed to seek because it is outside the block map.
error_code	An error occurred.

◆ rtems_rfs_block_map_open()

int rtems_rfs_block_map_open	(	rtems_rfs_file_system *	fs,
		rtems_rfs_inode_handle *	inode,
		rtems_rfs_block_map *	map
	)

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.

Parameters

[in]	fs	is the file system data.
[in]	inode	is a pointer to the inode the map belongs to.
[in]	map	is a pointer to the map that is opened.

Return values

0	Successful operation.
error_code	An error occurred.

◆ rtems_rfs_block_map_seek()

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 around the map.

Parameters

[in]	fs	is the file system data.
[in]	map	is a pointer to the map to search.
[in]	offset	is the distance to seek. It is signed.
[out]	block	will contain the block in when found.

Return values

0	Successful operation.
ENXIO	Failed to seek because it is outside the block map.
error_code	An error occurred.

◆ rtems_rfs_block_map_shrink()

int rtems_rfs_block_map_shrink	(	rtems_rfs_file_system *	fs,
		rtems_rfs_block_map *	map,
		size_t	blocks
	)

Grow the block map by the specified number of blocks.

Parameters

[in]	fs	is the file system data.
[in]	map	is a pointer to the open map to shrink.
[in]	blocks	is the number of blocks to shrink the map by. If more than the number of blocks the map is emptied.

Return values

0	Successful operation.
error_code	An error occurred.

Functions

Detailed Description

Function Documentation

◆ rtems_rfs_block_get_block_size()

◆ rtems_rfs_block_get_bpos()

◆ rtems_rfs_block_get_pos()

◆ rtems_rfs_block_get_size()

◆ rtems_rfs_block_map_close()

◆ rtems_rfs_block_map_find()

◆ rtems_rfs_block_map_free_all()

◆ rtems_rfs_block_map_grow()

◆ rtems_rfs_block_map_next_block()

◆ rtems_rfs_block_map_open()

◆ rtems_rfs_block_map_seek()

◆ rtems_rfs_block_map_shrink()