1 /* $OpenBSD: ufs_bmap.c,v 1.6 2016/12/17 16:26:46 krw Exp $ */ 2 /* $NetBSD: ufs_bmap.c,v 1.18 2013/06/19 17:51:27 dholland Exp $ */ 3 /* From: NetBSD: ufs_bmap.c,v 1.14 2001/11/08 05:00:51 chs Exp */ 4 5 /* 6 * Copyright (c) 1989, 1991, 1993 7 * The Regents of the University of California. All rights reserved. 8 * (c) UNIX System Laboratories, Inc. 9 * All or some portions of this file are derived from material licensed 10 * to the University of California by American Telephone and Telegraph 11 * Co. or Unix System Laboratories, Inc. and are reproduced herein with 12 * the permission of UNIX System Laboratories, Inc. 13 * 14 * Redistribution and use in source and binary forms, with or without 15 * modification, are permitted provided that the following conditions 16 * are met: 17 * 1. Redistributions of source code must retain the above copyright 18 * notice, this list of conditions and the following disclaimer. 19 * 2. Redistributions in binary form must reproduce the above copyright 20 * notice, this list of conditions and the following disclaimer in the 21 * documentation and/or other materials provided with the distribution. 22 * 3. Neither the name of the University nor the names of its contributors 23 * may be used to endorse or promote products derived from this software 24 * without specific prior written permission. 25 * 26 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 27 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 28 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 29 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 30 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 31 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 32 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 33 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 34 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 35 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 36 * SUCH DAMAGE. 37 * 38 * @(#)ufs_bmap.c 8.8 (Berkeley) 8/11/95 39 */ 40 41 #include <sys/param.h> 42 #include <sys/time.h> 43 44 #include <assert.h> 45 #include <errno.h> 46 #include <strings.h> 47 48 #include "makefs.h" 49 50 #include <ufs/ufs/dinode.h> 51 #include <ufs/ffs/fs.h> 52 53 #include "ffs/ufs_inode.h" 54 #include "ffs/ffs_extern.h" 55 56 /* 57 * Create an array of logical block number/offset pairs which represent the 58 * path of indirect blocks required to access a data block. The first "pair" 59 * contains the logical block number of the appropriate single, double or 60 * triple indirect block and the offset into the inode indirect block array. 61 * Note, the logical block number of the inode single/double/triple indirect 62 * block appears twice in the array, once with the offset into the i_ffs_ib and 63 * once with the offset into the page itself. 64 */ 65 int 66 ufs_getlbns(struct inode *ip, daddr_t bn, struct indir *ap, int *nump) 67 { 68 daddr_t metalbn, realbn; 69 int64_t blockcnt; 70 int lbc; 71 int i, numlevels, off; 72 u_long lognindir; 73 74 lognindir = ffs(NINDIR(ip->i_fs)) - 1; 75 if (nump) 76 *nump = 0; 77 numlevels = 0; 78 realbn = bn; 79 if ((long)bn < 0) 80 bn = -(long)bn; 81 82 assert (bn >= NDADDR); 83 84 /* 85 * Determine the number of levels of indirection. After this loop 86 * is done, blockcnt indicates the number of data blocks possible 87 * at the given level of indirection, and NIADDR - i is the number 88 * of levels of indirection needed to locate the requested block. 89 */ 90 91 bn -= NDADDR; 92 for (lbc = 0, i = NIADDR;; i--, bn -= blockcnt) { 93 if (i == 0) 94 return (EFBIG); 95 96 lbc += lognindir; 97 blockcnt = (int64_t)1 << lbc; 98 99 if (bn < blockcnt) 100 break; 101 } 102 103 /* Calculate the address of the first meta-block. */ 104 metalbn = -((realbn >= 0 ? realbn : -realbn) - bn + NIADDR - i); 105 106 /* 107 * At each iteration, off is the offset into the bap array which is 108 * an array of disk addresses at the current level of indirection. 109 * The logical block number and the offset in that block are stored 110 * into the argument array. 111 */ 112 ap->in_lbn = metalbn; 113 ap->in_off = off = NIADDR - i; 114 ap->in_exists = 0; 115 ap++; 116 for (++numlevels; i <= NIADDR; i++) { 117 /* If searching for a meta-data block, quit when found. */ 118 if (metalbn == realbn) 119 break; 120 121 lbc -= lognindir; 122 blockcnt = (int64_t)1 << lbc; 123 off = (bn >> lbc) & (NINDIR(ip->i_fs) - 1); 124 125 ++numlevels; 126 ap->in_lbn = metalbn; 127 ap->in_off = off; 128 ap->in_exists = 0; 129 ++ap; 130 131 metalbn -= -1 + (off << lbc); 132 } 133 if (nump) 134 *nump = numlevels; 135 return (0); 136 } 137