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 * $FreeBSD$
39 */
40
41#include <sys/param.h>
42
43#include <sys/proc.h>
44#include <sys/sdt.h>
45#include <sys/systm.h>
46#include <sys/bio.h>
47#include <sys/buf.h>
48#include <sys/lock.h>
49#include <sys/ucred.h>
50#include <sys/vnode.h>
51
52#include <fs/ext2fs/fs.h>
53#include <fs/ext2fs/inode.h>
54#include <fs/ext2fs/ext2fs.h>
55#include <fs/ext2fs/ext2_extern.h>
56#include <fs/ext2fs/fs.h>
57#include <fs/ext2fs/ext2_extents.h>
58#include <fs/ext2fs/ext2_mount.h>
59#include <fs/ext2fs/ext2_dinode.h>
60
61/*
62 * Return buffer with the contents of block "offset" from the beginning of
63 * directory "ip".  If "res" is non-zero, fill it in with a pointer to the
64 * remaining space in the directory.
65 */
66int
67ext2_blkatoff(struct vnode *vp, off_t offset, char **res, struct buf **bpp)
68{
69	struct inode *ip;
70	struct m_ext2fs *fs;
71	struct buf *bp;
72	e2fs_lbn_t lbn;
73	int error, bsize;
74
75	ip = VTOI(vp);
76	fs = ip->i_e2fs;
77	lbn = lblkno(fs, offset);
78	bsize = blksize(fs, ip, lbn);
79
80	if ((error = bread(vp, lbn, bsize, NOCRED, &bp)) != 0) {
81		brelse(bp);
82		return (error);
83	}
84	error = ext2_dir_blk_csum_verify(ip, bp);
85	if (error != 0) {
86		brelse(bp);
87		return (error);
88	}
89	if (res)
90		*res = (char *)bp->b_data + blkoff(fs, offset);
91
92	*bpp = bp;
93
94	return (0);
95}
96
97/*
98 * Update the cluster map because of an allocation of free like ffs.
99 *
100 * Cnt == 1 means free; cnt == -1 means allocating.
101 */
102void
103ext2_clusteracct(struct m_ext2fs *fs, char *bbp, int cg, e4fs_daddr_t bno, int cnt)
104{
105	int32_t *sump = fs->e2fs_clustersum[cg].cs_sum;
106	int32_t *lp;
107	e4fs_daddr_t start, end, loc, forw, back;
108	int bit, i;
109
110	/* Initialize the cluster summary array. */
111	if (fs->e2fs_clustersum[cg].cs_init == 0) {
112		int run = 0;
113
114		bit = 1;
115		loc = 0;
116
117		for (i = 0; i < fs->e2fs->e2fs_fpg; i++) {
118			if ((bbp[loc] & bit) == 0)
119				run++;
120			else if (run != 0) {
121				if (run > fs->e2fs_contigsumsize)
122					run = fs->e2fs_contigsumsize;
123				sump[run]++;
124				run = 0;
125			}
126			if ((i & (NBBY - 1)) != (NBBY - 1))
127				bit <<= 1;
128			else {
129				loc++;
130				bit = 1;
131			}
132		}
133		if (run != 0) {
134			if (run > fs->e2fs_contigsumsize)
135				run = fs->e2fs_contigsumsize;
136			sump[run]++;
137		}
138		fs->e2fs_clustersum[cg].cs_init = 1;
139	}
140
141	if (fs->e2fs_contigsumsize <= 0)
142		return;
143
144	/* Find the size of the cluster going forward. */
145	start = bno + 1;
146	end = start + fs->e2fs_contigsumsize;
147	if (end > fs->e2fs->e2fs_fpg)
148		end = fs->e2fs->e2fs_fpg;
149	loc = start / NBBY;
150	bit = 1 << (start % NBBY);
151	for (i = start; i < end; i++) {
152		if ((bbp[loc] & bit) != 0)
153			break;
154		if ((i & (NBBY - 1)) != (NBBY - 1))
155			bit <<= 1;
156		else {
157			loc++;
158			bit = 1;
159		}
160	}
161	forw = i - start;
162
163	/* Find the size of the cluster going backward. */
164	start = bno - 1;
165	end = start - fs->e2fs_contigsumsize;
166	if (end < 0)
167		end = -1;
168	loc = start / NBBY;
169	bit = 1 << (start % NBBY);
170	for (i = start; i > end; i--) {
171		if ((bbp[loc] & bit) != 0)
172			break;
173		if ((i & (NBBY - 1)) != 0)
174			bit >>= 1;
175		else {
176			loc--;
177			bit = 1 << (NBBY - 1);
178		}
179	}
180	back = start - i;
181
182	/*
183	 * Account for old cluster and the possibly new forward and
184	 * back clusters.
185	 */
186	i = back + forw + 1;
187	if (i > fs->e2fs_contigsumsize)
188		i = fs->e2fs_contigsumsize;
189	sump[i] += cnt;
190	if (back > 0)
191		sump[back] -= cnt;
192	if (forw > 0)
193		sump[forw] -= cnt;
194
195	/* Update cluster summary information. */
196	lp = &sump[fs->e2fs_contigsumsize];
197	for (i = fs->e2fs_contigsumsize; i > 0; i--)
198		if (*lp-- > 0)
199			break;
200	fs->e2fs_maxcluster[cg] = i;
201}
202