300 lines
8.9 KiB
C
300 lines
8.9 KiB
C
/*
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* Copyright (c) 1989, 1991, 1993
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* The Regents of the University of California. All rights reserved.
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* (c) UNIX System Laboratories, Inc.
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* All or some portions of this file are derived from material licensed
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* to the University of California by American Telephone and Telegraph
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* Co. or Unix System Laboratories, Inc. and are reproduced herein with
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* the permission of UNIX System Laboratories, Inc.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by the University of
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* California, Berkeley and its contributors.
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* 4. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* @(#)ufs_bmap.c 8.6 (Berkeley) 1/21/94
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* $Id: ufs_bmap.c,v 1.3 1994/08/02 07:54:52 davidg Exp $
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*/
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#include <sys/param.h>
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#include <sys/buf.h>
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#include <sys/proc.h>
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#include <sys/vnode.h>
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#include <sys/mount.h>
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#include <sys/resourcevar.h>
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#include <sys/trace.h>
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#include <miscfs/specfs/specdev.h>
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#include <ufs/ufs/quota.h>
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#include <ufs/ufs/inode.h>
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#include <ufs/ufs/ufsmount.h>
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#include <ufs/ufs/ufs_extern.h>
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int ufs_bmaparray __P((struct vnode *, daddr_t, daddr_t *, struct indir *, int *, int *));
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/*
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* Bmap converts a the logical block number of a file to its physical block
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* number on the disk. The conversion is done by using the logical block
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* number to index into the array of block pointers described by the dinode.
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*/
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int
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ufs_bmap(ap)
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struct vop_bmap_args /* {
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struct vnode *a_vp;
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daddr_t a_bn;
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struct vnode **a_vpp;
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daddr_t *a_bnp;
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int *a_runp;
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} */ *ap;
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{
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/*
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* Check for underlying vnode requests and ensure that logical
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* to physical mapping is requested.
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*/
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if (ap->a_vpp != NULL)
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*ap->a_vpp = VTOI(ap->a_vp)->i_devvp;
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if (ap->a_bnp == NULL)
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return (0);
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return (ufs_bmaparray(ap->a_vp, ap->a_bn, ap->a_bnp, NULL, NULL,
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ap->a_runp));
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}
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/*
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* Indirect blocks are now on the vnode for the file. They are given negative
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* logical block numbers. Indirect blocks are addressed by the negative
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* address of the first data block to which they point. Double indirect blocks
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* are addressed by one less than the address of the first indirect block to
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* which they point. Triple indirect blocks are addressed by one less than
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* the address of the first double indirect block to which they point.
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*
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* ufs_bmaparray does the bmap conversion, and if requested returns the
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* array of logical blocks which must be traversed to get to a block.
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* Each entry contains the offset into that block that gets you to the
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* next block and the disk address of the block (if it is assigned).
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*/
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int
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ufs_bmaparray(vp, bn, bnp, ap, nump, runp)
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struct vnode *vp;
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register daddr_t bn;
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daddr_t *bnp;
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struct indir *ap;
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int *nump;
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int *runp;
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{
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register struct inode *ip;
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struct buf *bp;
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struct ufsmount *ump;
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struct mount *mp;
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struct vnode *devvp;
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struct indir a[NIADDR], *xap;
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daddr_t daddr;
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long metalbn;
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int error, maxrun = 0, num;
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ip = VTOI(vp);
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mp = vp->v_mount;
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ump = VFSTOUFS(mp);
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#ifdef DIAGNOSTIC
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if (ap != NULL && nump == NULL || ap == NULL && nump != NULL)
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panic("ufs_bmaparray: invalid arguments");
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#endif
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if (runp) {
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/*
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* XXX
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* If MAXBSIZE is the largest transfer the disks can handle,
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* we probably want maxrun to be 1 block less so that we
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* don't create a block larger than the device can handle.
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*/
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*runp = 0;
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maxrun = MAXBSIZE / mp->mnt_stat.f_iosize - 1;
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}
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xap = ap == NULL ? a : ap;
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if (!nump)
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nump = #
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error = ufs_getlbns(vp, bn, xap, nump);
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if (error)
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return (error);
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num = *nump;
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if (num == 0) {
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*bnp = blkptrtodb(ump, ip->i_db[bn]);
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if (*bnp == 0)
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*bnp = -1;
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else if (runp)
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for (++bn; bn < NDADDR && *runp < maxrun &&
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is_sequential(ump, ip->i_db[bn - 1], ip->i_db[bn]);
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++bn, ++*runp);
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return (0);
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}
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/* Get disk address out of indirect block array */
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daddr = ip->i_ib[xap->in_off];
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devvp = VFSTOUFS(vp->v_mount)->um_devvp;
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for (bp = NULL, ++xap; --num; ++xap) {
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/*
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* Exit the loop if there is no disk address assigned yet and
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* the indirect block isn't in the cache, or if we were
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* looking for an indirect block and we've found it.
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*/
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metalbn = xap->in_lbn;
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if ((daddr == 0 && !incore(vp, metalbn)) || metalbn == bn)
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break;
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/*
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* If we get here, we've either got the block in the cache
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* or we have a disk address for it, go fetch it.
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*/
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if (bp)
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brelse(bp);
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xap->in_exists = 1;
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bp = getblk(vp, metalbn, mp->mnt_stat.f_iosize, 0, 0);
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if (bp->b_flags & (B_DONE | B_DELWRI)) {
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trace(TR_BREADHIT, pack(vp, size), metalbn);
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}
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#ifdef DIAGNOSTIC
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else if (!daddr)
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panic("ufs_bmaparry: indirect block not in cache");
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#endif
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else {
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trace(TR_BREADMISS, pack(vp, size), metalbn);
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bp->b_blkno = blkptrtodb(ump, daddr);
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bp->b_flags |= B_READ;
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VOP_STRATEGY(bp);
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curproc->p_stats->p_ru.ru_inblock++; /* XXX */
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error = biowait(bp);
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if (error) {
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brelse(bp);
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return (error);
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}
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}
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daddr = ((daddr_t *)bp->b_data)[xap->in_off];
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if (num == 1 && daddr && runp)
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for (bn = xap->in_off + 1;
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bn < MNINDIR(ump) && *runp < maxrun &&
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is_sequential(ump, ((daddr_t *)bp->b_data)[bn - 1],
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((daddr_t *)bp->b_data)[bn]);
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++bn, ++*runp);
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}
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if (bp)
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brelse(bp);
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daddr = blkptrtodb(ump, daddr);
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*bnp = daddr == 0 ? -1 : daddr;
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return (0);
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}
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/*
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* Create an array of logical block number/offset pairs which represent the
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* path of indirect blocks required to access a data block. The first "pair"
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* contains the logical block number of the appropriate single, double or
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* triple indirect block and the offset into the inode indirect block array.
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* Note, the logical block number of the inode single/double/triple indirect
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* block appears twice in the array, once with the offset into the i_ib and
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* once with the offset into the page itself.
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*/
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int
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ufs_getlbns(vp, bn, ap, nump)
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struct vnode *vp;
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register daddr_t bn;
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struct indir *ap;
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int *nump;
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{
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long metalbn, realbn;
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struct ufsmount *ump;
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int blockcnt, i, numlevels, off;
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ump = VFSTOUFS(vp->v_mount);
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if (nump)
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*nump = 0;
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numlevels = 0;
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realbn = bn;
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if ((long)bn < 0)
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bn = -(long)bn;
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/* The first NDADDR blocks are direct blocks. */
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if (bn < NDADDR)
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return (0);
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/*
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* Determine the number of levels of indirection. After this loop
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* is done, blockcnt indicates the number of data blocks possible
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* at the given level of indirection, and NIADDR - i is the number
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* of levels of indirection needed to locate the requested block.
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*/
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for (blockcnt = 1, i = NIADDR, bn -= NDADDR;; i--, bn -= blockcnt) {
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if (i == 0)
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return (EFBIG);
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blockcnt *= MNINDIR(ump);
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if (bn < blockcnt)
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break;
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}
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/* Calculate the address of the first meta-block. */
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if (realbn >= 0)
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metalbn = -(realbn - bn + NIADDR - i);
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else
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metalbn = -(-realbn - bn + NIADDR - i);
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/*
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* At each iteration, off is the offset into the bap array which is
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* an array of disk addresses at the current level of indirection.
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* The logical block number and the offset in that block are stored
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* into the argument array.
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*/
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ap->in_lbn = metalbn;
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ap->in_off = off = NIADDR - i;
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ap->in_exists = 0;
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ap++;
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for (++numlevels; i <= NIADDR; i++) {
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/* If searching for a meta-data block, quit when found. */
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if (metalbn == realbn)
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break;
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blockcnt /= MNINDIR(ump);
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off = (bn / blockcnt) % MNINDIR(ump);
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++numlevels;
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ap->in_lbn = metalbn;
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ap->in_off = off;
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ap->in_exists = 0;
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++ap;
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metalbn -= -1 + off * blockcnt;
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}
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if (nump)
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*nump = numlevels;
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return (0);
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}
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