block.c File Reference

minix: allocating and freeing data blocks (zones), and reading and writing them, through the block cache for the ones read often. More...

#include <ds/bitmap.h>
#include <minix.h>

Go to the source code of this file.

Functions
blk_t	minix_block_alloc (struct minix *desc)
	Allocates a free zone: its bit is set in the zone bitmap, which is written back to the disk at once.
void	minix_block_free (struct minix *desc, blk_t blk)
	Frees a zone: its bit is cleared in the zone bitmap, which is written back at once, and its copy in the block cache goes.
ssize_t	minix_block_read (struct minix *desc, blk_t blk, void *buf)
	Reads a block from the disk.
ssize_t	minix_block_write (struct minix *desc, blk_t blk, void *buf)
	Writes a block to the disk.
int	minix_bcache_get (struct minix *desc, blk_t blk, void **data)
	Gets a block from the block cache, reading it from the disk into the cache if it isn't there.

Detailed Description

minix: allocating and freeing data blocks (zones), and reading and writing them, through the block cache for the ones read often.

Definition in file block.c.

Function Documentation

minix_bcache_get()

int minix_bcache_get	(	struct minix *	desc,
		blk_t	blk,
		void **	data )

Gets a block from the block cache, reading it from the disk into the cache if it isn't there.

The cache keeps the block's memory.

Parameters

desc	the mounted filesystem
blk	the block number
data	set to the cached block

Returns

0, -ENOMEM, or a negative errno from the read

Definition at line 97 of file block.c.

References minix::bcache, bcache_find(), bcache_insert(), minix::bs, kmalloc(), minix_bcache_get(), minix_block_read(), and NULL.

Referenced by free_tree(), minix_bcache_get(), minix_inode_block_read(), and minix_inode_block_write().

minix_block_alloc()

blk_t minix_block_alloc

(

struct minix *

desc

)

Allocates a free zone: its bit is set in the zone bitmap, which is written back to the disk at once.

Parameters

desc	the mounted filesystem

Returns

the zone's block number, or 0 if the filesystem is full

Definition at line 16 of file block.c.

References minix::bs, minix_superblock::firstdatazone, bitmap::map, bitmap::max_idx, minix_block_alloc(), minix::superblock, minix::supernode, vfs_write(), minix::zmap, minix_superblock::zmap_blocks, and minix::zmap_off.

Referenced by minix_block_alloc(), minix_inode_block_write(), and table_alloc().

minix_block_free()

void minix_block_free	(	struct minix *	desc,
		blk_t	blk )

Frees a zone: its bit is cleared in the zone bitmap, which is written back at once, and its copy in the block cache goes.

Parameters

desc	the mounted filesystem
blk	the zone's block number

Definition at line 42 of file block.c.

References minix::bcache, bcache_remove(), minix::bs, minix_superblock::firstdatazone, bitmap::map, bitmap::max_idx, minix_block_free(), minix::superblock, minix::supernode, vfs_write(), minix::zmap, minix_superblock::zmap_blocks, and minix::zmap_off.

Referenced by free_tree(), and minix_block_free().

minix_block_read()

ssize_t minix_block_read	(	struct minix *	desc,
		blk_t	blk,
		void *	buf )

Reads a block from the disk.

Parameters

desc	the mounted filesystem
blk	the block number
buf	where it goes, a block's size

Returns

the number of bytes read, or a negative errno

Definition at line 70 of file block.c.

References minix::bs, minix_block_read(), minix::supernode, and vfs_read().

Referenced by minix_bcache_get(), minix_block_read(), and minix_inode_block_read().

minix_block_write()

ssize_t minix_block_write	(	struct minix *	desc,
		blk_t	blk,
		void *	buf )

Writes a block to the disk.

Parameters

desc	the mounted filesystem
blk	the block number
buf	the block's new contents

Returns

the number of bytes written, or a negative errno

Definition at line 83 of file block.c.

References minix::bs, minix_block_write(), minix::supernode, and vfs_write().

Referenced by free_tree(), minix_block_write(), minix_inode_block_write(), and table_alloc().