1 /* $NetBSD: ufs_bmap.c,v 1.11 2002/01/31 19:37:15 tv Exp $ */ 2 /* From: NetBSD: ufs_bmap.c,v 1.14 2001/11/08 05:00:51 chs Exp */ 3 4 /* 5 * Copyright (c) 1989, 1991, 1993 6 * The Regents of the University of California. All rights reserved. 7 * (c) UNIX System Laboratories, Inc. 8 * All or some portions of this file are derived from material licensed 9 * to the University of California by American Telephone and Telegraph 10 * Co. or Unix System Laboratories, Inc. and are reproduced herein with 11 * the permission of UNIX System Laboratories, Inc. 12 * 13 * Redistribution and use in source and binary forms, with or without 14 * modification, are permitted provided that the following conditions 15 * are met: 16 * 1. Redistributions of source code must retain the above copyright 17 * notice, this list of conditions and the following disclaimer. 18 * 2. Redistributions in binary form must reproduce the above copyright 19 * notice, this list of conditions and the following disclaimer in the 20 * documentation and/or other materials provided with the distribution. 21 * 3. All advertising materials mentioning features or use of this software 22 * must display the following acknowledgement: 23 * This product includes software developed by the University of 24 * California, Berkeley and its contributors. 25 * 4. Neither the name of the University nor the names of its contributors 26 * may be used to endorse or promote products derived from this software 27 * without specific prior written permission. 28 * 29 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 30 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 31 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 32 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 33 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 34 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 35 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 36 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 37 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 38 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 39 * SUCH DAMAGE. 40 * 41 * @(#)ufs_bmap.c 8.8 (Berkeley) 8/11/95 42 */ 43 44 #include <sys/cdefs.h> 45 #if defined(__RCSID) && !defined(__lint) 46 __RCSID("$NetBSD: ufs_bmap.c,v 1.11 2002/01/31 19:37:15 tv Exp $"); 47 #endif /* !__lint */ 48 49 #include <sys/param.h> 50 #include <sys/time.h> 51 52 #include <assert.h> 53 #include <errno.h> 54 #include <strings.h> 55 56 #include "makefs.h" 57 58 #include <ufs/ufs/dinode.h> 59 #include <ufs/ufs/ufs_bswap.h> 60 #include <ufs/ffs/fs.h> 61 62 #include "ffs/ufs_inode.h" 63 #include "ffs/ffs_extern.h" 64 65 /* 66 * Create an array of logical block number/offset pairs which represent the 67 * path of indirect blocks required to access a data block. The first "pair" 68 * contains the logical block number of the appropriate single, double or 69 * triple indirect block and the offset into the inode indirect block array. 70 * Note, the logical block number of the inode single/double/triple indirect 71 * block appears twice in the array, once with the offset into the i_ffs_ib and 72 * once with the offset into the page itself. 73 */ 74 int 75 ufs_getlbns(struct inode *ip, ufs_daddr_t bn, struct indir *ap, int *nump) 76 { 77 long metalbn, realbn; 78 int64_t blockcnt; 79 int lbc; 80 int i, numlevels, off; 81 u_long lognindir; 82 83 lognindir = ffs(NINDIR(ip->i_fs)) - 1; 84 if (nump) 85 *nump = 0; 86 numlevels = 0; 87 realbn = bn; 88 if ((long)bn < 0) 89 bn = -(long)bn; 90 91 assert (bn >= NDADDR); 92 93 /* 94 * Determine the number of levels of indirection. After this loop 95 * is done, blockcnt indicates the number of data blocks possible 96 * at the given level of indirection, and NIADDR - i is the number 97 * of levels of indirection needed to locate the requested block. 98 */ 99 100 bn -= NDADDR; 101 for (lbc = 0, i = NIADDR;; i--, bn -= blockcnt) { 102 if (i == 0) 103 return (EFBIG); 104 105 lbc += lognindir; 106 blockcnt = (int64_t)1 << lbc; 107 108 if (bn < blockcnt) 109 break; 110 } 111 112 /* Calculate the address of the first meta-block. */ 113 if (realbn >= 0) 114 metalbn = -(realbn - bn + NIADDR - i); 115 else 116 metalbn = -(-realbn - bn + NIADDR - i); 117 118 /* 119 * At each iteration, off is the offset into the bap array which is 120 * an array of disk addresses at the current level of indirection. 121 * The logical block number and the offset in that block are stored 122 * into the argument array. 123 */ 124 ap->in_lbn = metalbn; 125 ap->in_off = off = NIADDR - i; 126 ap->in_exists = 0; 127 ap++; 128 for (++numlevels; i <= NIADDR; i++) { 129 /* If searching for a meta-data block, quit when found. */ 130 if (metalbn == realbn) 131 break; 132 133 lbc -= lognindir; 134 blockcnt = (int64_t)1 << lbc; 135 off = (bn >> lbc) & (NINDIR(ip->i_fs) - 1); 136 137 ++numlevels; 138 ap->in_lbn = metalbn; 139 ap->in_off = off; 140 ap->in_exists = 0; 141 ++ap; 142 143 metalbn -= -1 + (off << lbc); 144 } 145 if (nump) 146 *nump = numlevels; 147 return (0); 148 } 149