dal

Disk abstraction layer. More...

Functions
void	soOpenDisk (const char *devname)
	Open disk at sofs19 abstraction level. More...
void	soCloseDisk ()
	Close disk at sofs19 abstraction level. More...
void	soOpenSuperBlock ()
	Open the superblock dealer. More...
void	soCloseSuperBlock ()
	Close the superblock dealer. More...
void	soSaveSuperBlock ()
	Save superblock to disk. More...
SOSuperBlock *	soGetSuperBlockPointer ()
	Get a pointer to the superblock. More...
void	soOpenInodeTable ()
	Open inode table dealer. More...
void	soCloseInodeTable ()
	Close the inode table dealer. More...
int	soOpenInode (uint32_t in)
	open inode More...
void	soCheckInodeHandler (int ih, const char *funcname=__FUNCTION__)
	Check given handler, throwing an exception in case of error. More...
SOInode *	soGetInodePointer (int ih)
	get pointer to an open inode More...
void	soSaveInode (int ih)
	Save an open inode to disk. More...
void	soCloseInode (int ih)
	Close an open inode. More...
uint32_t	soGetInodeNumber (int ih)
	Return the number of the inode associated to the given handler. More...
bool	soCheckInodeAccess (int ih, int access)
	check an open inode against a requested access More...
void	soReadDataBlock (uint32_t bn, void *buf)
	Read a block of the data zone. More...
void	soWriteDataBlock (uint32_t bn, void *buf)
	Write a block of the data zone. More...

Detailed Description

Disk abstraction layer.

This layer is used to prevent higher level functions from access disk blocks at raw level.

Function Documentation

soOpenDisk()

void sofs19::soOpenDisk

(

const char *

devname

)

Open disk at sofs19 abstraction level.

Open disk at raw level and then open superblok (SB) and inode table (IT) abstraction modules. The other sofs19 abstraction modules do not need to be initialized. They are: free inode list table (FILT) module, free block list table (FBLT) module, and data zone (DZ) module.

soCloseDisk()

void sofs19::soCloseDisk

(

)

Close disk at sofs19 abstraction level.

First close sofs19 abstraction modules and then close disk at raw level.

soOpenSuperBlock()

void sofs19::soOpenSuperBlock

(

)

Open the superblock dealer.

Prepare the internal data structure of the superblock dealer

soCloseSuperBlock()

void sofs19::soCloseSuperBlock

(

)

Close the superblock dealer.

Save superblock to disk and close dealer Do nothing if not loaded

soSaveSuperBlock()

void sofs19::soSaveSuperBlock

(

)

Save superblock to disk.

Do nothing if not loaded

soGetSuperBlockPointer()

SOSuperBlock* sofs19::soGetSuperBlockPointer

(

)

Get a pointer to the superblock.

Load the superblock, if not done yet

Returns

Pointer to the superblock

soOpenInodeTable()

void sofs19::soOpenInodeTable

(

)

Open inode table dealer.

Prepare the internal data structure for the inode table dealer

soCloseInodeTable()

void sofs19::soCloseInodeTable

(

)

Close the inode table dealer.

Save to disk all openning inodes and close dealer

soOpenInode()

int sofs19::soOpenInode

(

uint32_t

in

)

open inode

If inode is already open, just increment usecount; otherwise, transfer the inode from disk and put usecount at 1.

Parameters

in	the number of the inode to open

Returns

inode handler

soCheckInodeHandler()

void sofs19::soCheckInodeHandler	(	int	ih,
		const char *	funcname = __FUNCTION__
	)

Check given handler, throwing an exception in case of error.

Parameters

ih	the handler to be checked
funcname	name of the function making the ckeck

soGetInodePointer()

SOInode* sofs19::soGetInodePointer

(

int

ih

)

get pointer to an open inode

A pointer to the SOInode structured where the inode is loaded is returned.

Parameters

ih	inode handler

Returns

pointer to the inode

soSaveInode()

void sofs19::soSaveInode

(

int

ih

)

Save an open inode to disk.

The inode is not closed.

Parameters

ih	inode handler

soCloseInode()

void sofs19::soCloseInode

(

int

ih

)

Close an open inode.

Decrement usecount of given inode, releasing slot if 0 is reached.

Parameters

ih	inode handler

soGetInodeNumber()

uint32_t sofs19::soGetInodeNumber

(

int

ih

)

Return the number of the inode associated to the given handler.

Parameters

ih	inode handler

Returns

inode number

soCheckInodeAccess()

bool sofs19::soCheckInodeAccess	(	int	ih,
		int	access
	)

check an open inode against a requested access

access is a bitwise OR of one or more of R_OK, W_OK, and X_OK

See also

man 2 access

Parameters

ih	inode handler
access	requested access

Returns

true, for access granted; false for access denied

soReadDataBlock()

void sofs19::soReadDataBlock	(	uint32_t	bn,
		void *	buf
	)

Read a block of the data zone.

Parameters

[in]	bn	number of block to be read
[in]	buf	pointer to the buffer where the data must be read into

soWriteDataBlock()

void sofs19::soWriteDataBlock	(	uint32_t	bn,
		void *	buf
	)

Write a block of the data zone.

Parameters

[in]	bn	number of block to be read
[in]	buf	pointer to the buffer where the data must be written from