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+/*
+ * Copyright (c) 1989, 1991, 1993
+ * The Regents of the University of California. All rights reserved.
+ * (c) UNIX System Laboratories, Inc.
+ * All or some portions of this file are derived from material licensed
+ * to the University of California by American Telephone and Telegraph
+ * Co. or Unix System Laboratories, Inc. and are reproduced herein with
+ * the permission of UNIX System Laboratories, Inc.
+ *
+ * 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.
+ *
+ * @(#)ufs_bmap.c 8.6 (Berkeley) 1/21/94
+ */
+
+#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/ufs/ufs_extern.h>
+
+/*
+ * Bmap converts a the logical block number of a file to its physical block
+ * number on the disk. The conversion is done by using the logical block
+ * number to index into the array of block pointers described by the dinode.
+ */
+int
+ufs_bmap(ap)
+ struct vop_bmap_args /* {
+ struct vnode *a_vp;
+ daddr_t a_bn;
+ struct vnode **a_vpp;
+ daddr_t *a_bnp;
+ int *a_runp;
+ } */ *ap;
+{
+ /*
+ * Check for underlying vnode requests and ensure that logical
+ * to physical mapping is requested.
+ */
+ if (ap->a_vpp != NULL)
+ *ap->a_vpp = VTOI(ap->a_vp)->i_devvp;
+ if (ap->a_bnp == NULL)
+ return (0);
+
+ return (ufs_bmaparray(ap->a_vp, ap->a_bn, ap->a_bnp, NULL, NULL,
+ ap->a_runp));
+}
+
+/*
+ * Indirect blocks are now on the vnode for the file. They are given negative
+ * logical block numbers. Indirect blocks are addressed by the negative
+ * address of the first data block to which they point. Double indirect blocks
+ * are addressed by one less than the address of the first indirect block to
+ * which they point. Triple indirect blocks are addressed by one less than
+ * the address of the first double indirect block to which they point.
+ *
+ * ufs_bmaparray does the bmap conversion, and if requested returns the
+ * array of logical blocks which must be traversed to get to a block.
+ * Each entry contains the offset into that block that gets you to the
+ * next block and the disk address of the block (if it is assigned).
+ */
+
+int
+ufs_bmaparray(vp, bn, bnp, ap, nump, runp)
+ struct vnode *vp;
+ register daddr_t bn;
+ daddr_t *bnp;
+ struct indir *ap;
+ int *nump;
+ int *runp;
+{
+ register struct inode *ip;
+ struct buf *bp;
+ struct ufsmount *ump;
+ struct mount *mp;
+ struct vnode *devvp;
+ struct indir a[NIADDR], *xap;
+ daddr_t daddr;
+ long metalbn;
+ int error, maxrun, num;
+
+ ip = VTOI(vp);
+ mp = vp->v_mount;
+ ump = VFSTOUFS(mp);
+#ifdef DIAGNOSTIC
+ if (ap != NULL && nump == NULL || ap == NULL && nump != NULL)
+ panic("ufs_bmaparray: invalid arguments");
+#endif
+
+ if (runp) {
+ /*
+ * XXX
+ * If MAXBSIZE is the largest transfer the disks can handle,
+ * we probably want maxrun to be 1 block less so that we
+ * don't create a block larger than the device can handle.
+ */
+ *runp = 0;
+ maxrun = MAXBSIZE / mp->mnt_stat.f_iosize - 1;
+ }
+
+ xap = ap == NULL ? a : ap;
+ if (!nump)
+ nump = &num;
+ if (error = ufs_getlbns(vp, bn, xap, nump))
+ return (error);
+
+ num = *nump;
+ if (num == 0) {
+ *bnp = blkptrtodb(ump, ip->i_db[bn]);
+ if (*bnp == 0)
+ *bnp = -1;
+ else if (runp)
+ for (++bn; bn < NDADDR && *runp < maxrun &&
+ is_sequential(ump, ip->i_db[bn - 1], ip->i_db[bn]);
+ ++bn, ++*runp);
+ return (0);
+ }
+
+
+ /* Get disk address out of indirect block array */
+ daddr = ip->i_ib[xap->in_off];
+
+ devvp = VFSTOUFS(vp->v_mount)->um_devvp;
+ for (bp = NULL, ++xap; --num; ++xap) {
+ /*
+ * Exit the loop if there is no disk address assigned yet and
+ * the indirect block isn't in the cache, or if we were
+ * looking for an indirect block and we've found it.
+ */
+
+ metalbn = xap->in_lbn;
+ if (daddr == 0 && !incore(vp, metalbn) || metalbn == bn)
+ break;
+ /*
+ * If we get here, we've either got the block in the cache
+ * or we have a disk address for it, go fetch it.
+ */
+ if (bp)
+ brelse(bp);
+
+ xap->in_exists = 1;
+ bp = getblk(vp, metalbn, mp->mnt_stat.f_iosize, 0, 0);
+ if (bp->b_flags & (B_DONE | B_DELWRI)) {
+ trace(TR_BREADHIT, pack(vp, size), metalbn);
+ }
+#ifdef DIAGNOSTIC
+ else if (!daddr)
+ panic("ufs_bmaparry: indirect block not in cache");
+#endif
+ else {
+ trace(TR_BREADMISS, pack(vp, size), metalbn);
+ bp->b_blkno = blkptrtodb(ump, daddr);
+ bp->b_flags |= B_READ;
+ VOP_STRATEGY(bp);
+ curproc->p_stats->p_ru.ru_inblock++; /* XXX */
+ if (error = biowait(bp)) {
+ brelse(bp);
+ return (error);
+ }
+ }
+
+ daddr = ((daddr_t *)bp->b_data)[xap->in_off];
+ if (num == 1 && daddr && runp)
+ for (bn = xap->in_off + 1;
+ bn < MNINDIR(ump) && *runp < maxrun &&
+ is_sequential(ump, ((daddr_t *)bp->b_data)[bn - 1],
+ ((daddr_t *)bp->b_data)[bn]);
+ ++bn, ++*runp);
+ }
+ if (bp)
+ brelse(bp);
+
+ daddr = blkptrtodb(ump, daddr);
+ *bnp = daddr == 0 ? -1 : daddr;
+ return (0);
+}
+
+/*
+ * Create an array of logical block number/offset pairs which represent the
+ * path of indirect blocks required to access a data block. The first "pair"
+ * contains the logical block number of the appropriate single, double or
+ * triple indirect block and the offset into the inode indirect block array.
+ * Note, the logical block number of the inode single/double/triple indirect
+ * block appears twice in the array, once with the offset into the i_ib and
+ * once with the offset into the page itself.
+ */
+int
+ufs_getlbns(vp, bn, ap, nump)
+ struct vnode *vp;
+ register daddr_t bn;
+ struct indir *ap;
+ int *nump;
+{
+ long metalbn, realbn;
+ struct ufsmount *ump;
+ int blockcnt, i, numlevels, off;
+
+ ump = VFSTOUFS(vp->v_mount);
+ if (nump)
+ *nump = 0;
+ numlevels = 0;
+ realbn = bn;
+ if ((long)bn < 0)
+ bn = -(long)bn;
+
+ /* The first NDADDR blocks are direct blocks. */
+ if (bn < NDADDR)
+ return (0);
+
+ /*
+ * Determine the number of levels of indirection. After this loop
+ * is done, blockcnt indicates the number of data blocks possible
+ * at the given level of indirection, and NIADDR - i is the number
+ * of levels of indirection needed to locate the requested block.
+ */
+ for (blockcnt = 1, i = NIADDR, bn -= NDADDR;; i--, bn -= blockcnt) {
+ if (i == 0)
+ return (EFBIG);
+ blockcnt *= MNINDIR(ump);
+ if (bn < blockcnt)
+ break;
+ }
+
+ /* Calculate the address of the first meta-block. */
+ if (realbn >= 0)
+ metalbn = -(realbn - bn + NIADDR - i);
+ else
+ metalbn = -(-realbn - bn + NIADDR - i);
+
+ /*
+ * At each iteration, off is the offset into the bap array which is
+ * an array of disk addresses at the current level of indirection.
+ * The logical block number and the offset in that block are stored
+ * into the argument array.
+ */
+ ap->in_lbn = metalbn;
+ ap->in_off = off = NIADDR - i;
+ ap->in_exists = 0;
+ ap++;
+ for (++numlevels; i <= NIADDR; i++) {
+ /* If searching for a meta-data block, quit when found. */
+ if (metalbn == realbn)
+ break;
+
+ blockcnt /= MNINDIR(ump);
+ off = (bn / blockcnt) % MNINDIR(ump);
+
+ ++numlevels;
+ ap->in_lbn = metalbn;
+ ap->in_off = off;
+ ap->in_exists = 0;
+ ++ap;
+
+ metalbn -= -1 + off * blockcnt;
+ }
+ if (nump)
+ *nump = numlevels;
+ return (0);
+}
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