1 /* $NetBSD: ufs_bmap.c,v 1.18 2013/06/19 17:51:27 dholland 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. Neither the name of the University nor the names of its contributors 22 * may be used to endorse or promote products derived from this software 23 * without specific prior written permission. 24 * 25 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 26 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 27 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 28 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 29 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 30 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 31 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 32 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 33 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 34 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 35 * SUCH DAMAGE. 36 * 37 * @(#)ufs_bmap.c 8.8 (Berkeley) 8/11/95 38 */ 39 40 #if HAVE_NBTOOL_CONFIG_H 41 #include "nbtool_config.h" 42 #endif 43 44 #include <sys/cdefs.h> 45 #if defined(__RCSID) && !defined(__lint) 46 __RCSID("$NetBSD: ufs_bmap.c,v 1.18 2013/06/19 17:51:27 dholland 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, daddr_t bn, struct indir *ap, int *nump) 76 { 77 daddr_t metalbn, realbn; 78 int64_t blockcnt; 79 int lbc; 80 int i, numlevels, off; 81 u_long lognindir; 82 83 lognindir = ffs(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 >= UFS_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 UFS_NIADDR - i is the number 97 * of levels of indirection needed to locate the requested block. 98 */ 99 100 bn -= UFS_NDADDR; 101 for (lbc = 0, i = UFS_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 metalbn = -((realbn >= 0 ? realbn : -realbn) - bn + UFS_NIADDR - i); 114 115 /* 116 * At each iteration, off is the offset into the bap array which is 117 * an array of disk addresses at the current level of indirection. 118 * The logical block number and the offset in that block are stored 119 * into the argument array. 120 */ 121 ap->in_lbn = metalbn; 122 ap->in_off = off = UFS_NIADDR - i; 123 ap->in_exists = 0; 124 ap++; 125 for (++numlevels; i <= UFS_NIADDR; i++) { 126 /* If searching for a meta-data block, quit when found. */ 127 if (metalbn == realbn) 128 break; 129 130 lbc -= lognindir; 131 blockcnt = (int64_t)1 << lbc; 132 off = (bn >> lbc) & (FFS_NINDIR(ip->i_fs) - 1); 133 134 ++numlevels; 135 ap->in_lbn = metalbn; 136 ap->in_off = off; 137 ap->in_exists = 0; 138 ++ap; 139 140 metalbn -= -1 + (off << lbc); 141 } 142 if (nump) 143 *nump = numlevels; 144 return (0); 145 } 146