lfs_balloc.c

来自「早期freebsd实现」· C语言 代码 · 共 137 行

/*
 * Copyright (c) 1989, 1991, 1993
 *	The Regents of the University of California.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *	This product includes software developed by the University of
 *	California, Berkeley and its contributors.
 * 4. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 *	@(#)lfs_balloc.c	8.1 (Berkeley) 6/11/93
 */
#include <sys/param.h>
#include <sys/buf.h>
#include <sys/proc.h>
#include <sys/vnode.h>
#include <sys/mount.h>
#include <sys/resourcevar.h>
#include <sys/trace.h>

#include <miscfs/specfs/specdev.h>

#include <ufs/ufs/quota.h>
#include <ufs/ufs/inode.h>
#include <ufs/ufs/ufsmount.h>

#include <ufs/lfs/lfs.h>
#include <ufs/lfs/lfs_extern.h>

int
lfs_balloc(vp, iosize, lbn, bpp)
	struct vnode *vp;
	u_long iosize;
	daddr_t lbn;
	struct buf **bpp;
{
	struct buf *ibp, *bp;
	struct inode *ip;
	struct lfs *fs;
	struct indir indirs[NIADDR+2];
	daddr_t daddr;
	int bb, error, i, num;

	ip = VTOI(vp);
	fs = ip->i_lfs;

	/* 
	 * Three cases: it's a block beyond the end of file, it's a block in
	 * the file that may or may not have been assigned a disk address or
	 * we're writing an entire block.  Note, if the daddr is unassigned,
	 * the block might still have existed in the cache (if it was read
	 * or written earlier).  If it did, make sure we don't count it as a
	 * new block or zero out its contents.  If it did not, make sure
	 * we allocate any necessary indirect blocks.
	 */

	*bpp = NULL;
	if (error = ufs_bmaparray(vp, lbn, &daddr, &indirs[0], &num, NULL ))
		return (error);

	*bpp = bp = getblk(vp, lbn, fs->lfs_bsize, 0, 0);
	bb = VFSTOUFS(vp->v_mount)->um_seqinc;
	if (daddr == UNASSIGNED)
		/* May need to allocate indirect blocks */
		for (i = 1; i < num; ++i)
			if (!indirs[i].in_exists) {
				ibp =
				    getblk(vp, indirs[i].in_lbn, fs->lfs_bsize,
					0, 0);
				if (!(ibp->b_flags & (B_DONE | B_DELWRI))) {
					if (!ISSPACE(fs, bb, curproc->p_ucred)){
						ibp->b_flags |= B_INVAL;
						brelse(ibp);
						error = ENOSPC;
					} else {
						ip->i_blocks += bb;
						ip->i_lfs->lfs_bfree -= bb;
						clrbuf(ibp);
						error = VOP_BWRITE(ibp);
					}
				} else
					panic ("Indirect block should not exist");
			}
	if (error) {
		if (bp)
			brelse(bp);
		return(error);
	}


	/* Now, we may need to allocate the data block */
	if (!(bp->b_flags & (B_CACHE | B_DONE | B_DELWRI))) {
		if (daddr == UNASSIGNED) 
			if (!ISSPACE(fs, bb, curproc->p_ucred)) {
				bp->b_flags |= B_INVAL;
				brelse(bp);
				return(ENOSPC);
			} else {
				ip->i_blocks += bb;
				ip->i_lfs->lfs_bfree -= bb;
				if (iosize != fs->lfs_bsize)
					clrbuf(bp);
			}
		else if (iosize == fs->lfs_bsize)
			bp->b_blkno = daddr;		/* Skip the I/O */
		else  {
			bp->b_blkno = daddr;
			bp->b_flags |= B_READ;
			VOP_STRATEGY(bp);
			return(biowait(bp));
		}
	}
	return (error);
}