inode.c

T-kernel 的extension源代码

/*
 *----------------------------------------------------------------------
 *    T-Kernel / Standard Extension
 *
 *    Copyright (C) 2006 by Ken Sakamura. All rights reserved.
 *    T-Kernel / Standard Extension is distributed 
 *      under the T-License for T-Kernel / Standard Extension.
 *----------------------------------------------------------------------
 *
 *    Version:   1.00.00
 *    Released by T-Engine Forum(http://www.t-engine.org) at 2006/8/11.
 *
 *----------------------------------------------------------------------
 */

/*
 *	@(#)inode.c (seio)
 *
 *	Standard input-output
 *	File reference node management
 */

#include "sfmgr.h"


/*
 * Initilization of file reference node connection queue
 */
EXPORT void inode_QueInit( FS *fs )
{
	W	i;

	/* Standard FS has no queue */
	if ( fs == (FS*)&STD_FS ) {
		return;
	}

	/* Initialization of queue */
	for ( i = 0; i < NQUE; i++ ) {
		QueInit(&fs->iqtbl[i]);
	}

	return;
}

/*
 * Check of file reference node connection queue.
 *	Confirm the queue to be empty. And, return error if it isn't empty.
 */
EXPORT ER inode_CheckEmpty( FS *fs )
{
	W	i;

	/* Standard FS has no queue */
	if ( fs == (FS*)&STD_FS ) {
		return E_OK;
	}

	/* Check of queue */
	for ( i = 0; i < NQUE; i++ ) {
		if ( !isQueEmpty(&fs->iqtbl[i]) ) {
			return E_BUSY;
		}
	}

	return E_OK;
}

/*
 * Registration of file reference node
 */
EXPORT void inode_Register( FS *fs, INODE *inode, UB omode )
{
	UW	qnum;

	/* Stop the root directory and standard input-output */
	if ( inode == NULL ) {
		return;
	}

	/* Update of the number of references */
	if ( (omode & O_ACCMODE) != O_RDONLY ) {
		++inode->wrefcnt;
	}
	if ( ++inode->refcnt > 1 ) {
		return;
	}

	/* Insert into queue */
	if ( fs != (FS*)&STD_FS ) {
		qnum = (UW)inode->ino & (UW)QUEMSK;
		QueInsert(&inode->q, &fs->iqtbl[qnum]);
	}

	return;
}

/*
 * Deletion of file reference node
 */
EXPORT void inode_Free( FS *fs, INODE *inode )
{
	/* Stop root directory and standard input-output */
	if ( inode == NULL ) {
		return;
	}

	/* Delete if there is no reference */
	if ( inode->refcnt <= 0 ) {
		if ( inode->exinf != NULL ) {
			Vfree(inode->exinf);
		}
		Vfree(inode);
	}

	return;
}

/*
 * Release of file reference node
 *	Stop the reference, and delete the unused file reference node.
 */
EXPORT ER inode_Release( FS *fs, INODE *inode, UB omode, BOOL force )
{
	ER	err = E_OK;

	/* Stop root directory and standard input-output */
	if ( inode == NULL ) {
		return err;
	}

	/* Stop writing reference */
	if (( fs != (FS*)&STD_FS )&&( (omode & O_ACCMODE) != O_RDONLY )) {
		if ( --inode->wrefcnt <= 0 ) {
			/* Synchronization */
			(void)SyncFS(fs->diskid, (VW)inode);
			err = CheckDiskError(fs, inode);
			if (( err < E_OK )&& !force ) {
				return err;
			}
		}
	}

	/* Stop reference */
	if ( inode->refcnt > 1 ) {
		inode->refcnt--;
		return err;	/* In-use */
	}

	/* Delete from queue */
	if ( fs != (FS*)&STD_FS ) {
		QueRemove(&inode->q);
	}

	/* Release of file reference node */
	if ( inode->exinf != NULL ) {
		Vfree(inode->exinf);
	}
	Vfree(inode);

	return err;
}

/* --------------------------------------------------------------------------- */

/*
 * Search of file reference node
 */
EXPORT INODE* inode_Search( FS *fs, ino_t ino )
{
	QUEUE	*q;
	UW	qnum;
	INODE	*inode;

	/* Selection of queue */
	qnum = (UW)ino & (UW)QUEMSK;

	/* Search */
	for ( q = fs->iqtbl[qnum].next; q != &fs->iqtbl[qnum]; q = q->next ) {
		inode = (INODE*)q;
		if ( inode->ino == ino ) {
			return inode;
		}
	}

	return NULL;
}

/*
 * Queue transfer of file reference node
 */
EXPORT void inode_ChangeQue( FS *fs, INODE *inode )
{
	UW	qnum;

	/* Stop the tentative reference */
	if ( inode->refcnt <= 0 ) {
		return;
	}

	/* Selection of queue */
	qnum = (UW)inode->ino & (UW)QUEMSK;

	/* Queue remove */
	QueRemove(&inode->q);
	QueInsert(&inode->q, &fs->iqtbl[qnum]);

	return;
}