1 /*-
2 * modified for Lites 1.1
3 *
4 * Aug 1995, Godmar Back (gback@cs.utah.edu)
5 * University of Utah, Department of Computer Science
6 */
7 /*-
8 * SPDX-License-Identifier: BSD-3-Clause
9 *
10 * Copyright (c) 1982, 1986, 1989, 1993
11 * The Regents of the University of California. All rights reserved.
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 * @(#)ffs_subr.c 8.2 (Berkeley) 9/21/93
38 * $FreeBSD: releng/12.0/sys/fs/ext2fs/ext2_subr.c 333584 2018-05-13 19:19:10Z fsu $
39 */
40
41 #include <sys/param.h>
42
43 #include <sys/proc.h>
44 #include <sys/systm.h>
45 #include <sys/bio.h>
46 #include <sys/buf.h>
47 #include <sys/lock.h>
48 #include <sys/ucred.h>
49 #include <sys/vnode.h>
50
51 #include <fs/ext2fs/fs.h>
52 #include <fs/ext2fs/inode.h>
53 #include <fs/ext2fs/ext2fs.h>
54 #include <fs/ext2fs/ext2_extern.h>
55 #include <fs/ext2fs/fs.h>
56 #include <fs/ext2fs/ext2_extents.h>
57 #include <fs/ext2fs/ext2_mount.h>
58 #include <fs/ext2fs/ext2_dinode.h>
59
60 /*
61 * Return buffer with the contents of block "offset" from the beginning of
62 * directory "ip". If "res" is non-zero, fill it in with a pointer to the
63 * remaining space in the directory.
64 */
65 int
66 ext2_blkatoff(struct vnode *vp, off_t offset, char **res, struct buf **bpp)
67 {
68 struct inode *ip;
69 struct m_ext2fs *fs;
70 struct buf *bp;
71 e2fs_lbn_t lbn;
72 int error, bsize;
73
74 ip = VTOI(vp);
75 fs = ip->i_e2fs;
76 lbn = lblkno(fs, offset);
77 bsize = blksize(fs, ip, lbn);
78
79 if ((error = bread(vp, lbn, bsize, NOCRED, &bp)) != 0) {
80 brelse(bp);
81 return (error);
82 }
83 error = ext2_dir_blk_csum_verify(ip, bp);
84 if (error != 0) {
85 brelse(bp);
86 return (error);
87 }
88 if (res)
89 *res = (char *)bp->b_data + blkoff(fs, offset);
90
91 *bpp = bp;
92
93 return (0);
94 }
95
96 /*
97 * Update the cluster map because of an allocation of free like ffs.
98 *
99 * Cnt == 1 means free; cnt == -1 means allocating.
100 */
101 void
102 ext2_clusteracct(struct m_ext2fs *fs, char *bbp, int cg, e4fs_daddr_t bno, int cnt)
103 {
104 int32_t *sump = fs->e2fs_clustersum[cg].cs_sum;
105 int32_t *lp;
106 e4fs_daddr_t start, end, loc, forw, back;
107 int bit, i;
108
109 /* Initialize the cluster summary array. */
110 if (fs->e2fs_clustersum[cg].cs_init == 0) {
111 int run = 0;
112
113 bit = 1;
114 loc = 0;
115
116 for (i = 0; i < fs->e2fs->e2fs_fpg; i++) {
117 if ((bbp[loc] & bit) == 0)
118 run++;
119 else if (run != 0) {
120 if (run > fs->e2fs_contigsumsize)
121 run = fs->e2fs_contigsumsize;
122 sump[run]++;
123 run = 0;
124 }
125 if ((i & (NBBY - 1)) != (NBBY - 1))
126 bit <<= 1;
127 else {
128 loc++;
129 bit = 1;
130 }
131 }
132 if (run != 0) {
133 if (run > fs->e2fs_contigsumsize)
134 run = fs->e2fs_contigsumsize;
135 sump[run]++;
136 }
137 fs->e2fs_clustersum[cg].cs_init = 1;
138 }
139
140 if (fs->e2fs_contigsumsize <= 0)
141 return;
142
143 /* Find the size of the cluster going forward. */
144 start = bno + 1;
145 end = start + fs->e2fs_contigsumsize;
146 if (end > fs->e2fs->e2fs_fpg)
147 end = fs->e2fs->e2fs_fpg;
148 loc = start / NBBY;
149 bit = 1 << (start % NBBY);
150 for (i = start; i < end; i++) {
151 if ((bbp[loc] & bit) != 0)
152 break;
153 if ((i & (NBBY - 1)) != (NBBY - 1))
154 bit <<= 1;
155 else {
156 loc++;
157 bit = 1;
158 }
159 }
160 forw = i - start;
161
162 /* Find the size of the cluster going backward. */
163 start = bno - 1;
164 end = start - fs->e2fs_contigsumsize;
165 if (end < 0)
166 end = -1;
167 loc = start / NBBY;
168 bit = 1 << (start % NBBY);
169 for (i = start; i > end; i--) {
170 if ((bbp[loc] & bit) != 0)
171 break;
172 if ((i & (NBBY - 1)) != 0)
173 bit >>= 1;
174 else {
175 loc--;
176 bit = 1 << (NBBY - 1);
177 }
178 }
179 back = start - i;
180
181 /*
182 * Account for old cluster and the possibly new forward and
183 * back clusters.
184 */
185 i = back + forw + 1;
186 if (i > fs->e2fs_contigsumsize)
187 i = fs->e2fs_contigsumsize;
188 sump[i] += cnt;
189 if (back > 0)
190 sump[back] -= cnt;
191 if (forw > 0)
192 sump[forw] -= cnt;
193
194 /* Update cluster summary information. */
195 lp = &sump[fs->e2fs_contigsumsize];
196 for (i = fs->e2fs_contigsumsize; i > 0; i--)
197 if (*lp-- > 0)
198 break;
199 fs->e2fs_maxcluster[cg] = i;
200 }
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