bcache.c File Reference

The block cache: a filesystem's blocks kept in memory, by a number the filesystem chooses (minix uses the block number), so that a block read again and again is read once. More...

#include <core/system.h>
#include <fs/bcache.h>

Go to the source code of this file.

Data Structures
struct	cache_block
	A cached block. More...

Functions
static int	bcache_eq (void *_a, void *_b)
	Says whether a cached block is the one whose number _b points to.
void	bcache_init (struct bcache *bcache)
	Sets up an empty block cache.
int	bcache_insert (struct bcache *bcache, uint64_t off, void *data)
	Adds a block to a cache, which keeps its memory from now on.
int	bcache_remove (struct bcache *bcache, uint64_t off)
	Takes a block out of a cache.
void *	bcache_find (struct bcache *bcache, uint64_t off)
	Finds a cached block.
void	bcache_dirty (struct bcache *bcache, uint64_t off)
	Marks a cached block as changed.

Detailed Description

The block cache: a filesystem's blocks kept in memory, by a number the filesystem chooses (minix uses the block number), so that a block read again and again is read once.

minix keeps its indirect zones there.

Definition in file bcache.c.

Function Documentation

bcache_dirty()

void bcache_dirty	(	struct bcache *	bcache,
		uint64_t	off )

Marks a cached block as changed.

Nothing writes dirty blocks back yet: the filesystems write their changes through at once.

Parameters

bcache	the cache
off	the block's number

Definition at line 124 of file bcache.c.

References bcache_dirty(), cache_block::dirty, hashmap_node::entry, hashmap_node::hash, bcache::hashmap, and cache_block::off.

Referenced by bcache_dirty().

bcache_eq()

int bcache_eq ( void * _a, void * _b )

static

Says whether a cached block is the one whose number _b points to.

Definition at line 22 of file bcache.c.

References bcache_eq(), and cache_block::off.

Referenced by bcache_eq(), and bcache_init().

bcache_find()

void * bcache_find	(	struct bcache *	bcache,
		uint64_t	off )

Finds a cached block.

Parameters

bcache	the cache
off	the block's number

Returns

its contents, or NULL if it isn't cached

Definition at line 100 of file bcache.c.

References bcache_find(), cache_block::data, hashmap_node::entry, hashmap_node::hash, bcache::hashmap, and NULL.

Referenced by bcache_find(), and minix_bcache_get().

bcache_init()

void bcache_init

(

struct bcache *

bcache

)

Sets up an empty block cache.

Parameters

bcache

the cache

Definition at line 35 of file bcache.c.

References bcache_eq(), bcache_init(), and bcache::hashmap.

Referenced by bcache_init(), bcache_insert(), and minix_load().

bcache_insert()

int bcache_insert	(	struct bcache *	bcache,
		uint64_t	off,
		void *	data )

Adds a block to a cache, which keeps its memory from now on.

Parameters

bcache	the cache, set up on first use
off	the block's number
data	its contents

Returns

0, -EINVAL if bcache is NULL, or -ENOMEM

Definition at line 48 of file bcache.c.

References bcache_init(), bcache_insert(), cache_block::data, bcache::hashmap, kmalloc(), M_ZERO, and cache_block::off.

Referenced by bcache_insert(), and minix_bcache_get().

bcache_remove()

int bcache_remove	(	struct bcache *	bcache,
		uint64_t	off )

Takes a block out of a cache.

Parameters

bcache	the cache
off	the block's number

Returns

0, or -1 if the block wasn't cached

Definition at line 73 of file bcache.c.

References bcache_remove(), hashmap_node::entry, hashmap_node::hash, bcache::hashmap, kfree(), NULL, and cache_block::off.

Referenced by bcache_remove(), minix_block_free(), and table_alloc().