xref: /freebsd/sys/fs/ext2fs/ext2_subr.c (revision a98ff317388a00b992f1bf8404dee596f9383f5e)
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  * Copyright (c) 1982, 1986, 1989, 1993
9  *	The Regents of the University of California.  All rights reserved.
10  *
11  * Redistribution and use in source and binary forms, with or without
12  * modification, are permitted provided that the following conditions
13  * are met:
14  * 1. Redistributions of source code must retain the above copyright
15  *    notice, this list of conditions and the following disclaimer.
16  * 2. Redistributions in binary form must reproduce the above copyright
17  *    notice, this list of conditions and the following disclaimer in the
18  *    documentation and/or other materials provided with the distribution.
19  * 4. Neither the name of the University nor the names of its contributors
20  *    may be used to endorse or promote products derived from this software
21  *    without specific prior written permission.
22  *
23  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
24  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
25  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
26  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
27  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
28  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
29  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
30  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
31  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
32  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
33  * SUCH DAMAGE.
34  *
35  *	@(#)ffs_subr.c	8.2 (Berkeley) 9/21/93
36  * $FreeBSD$
37  */
38 
39 #include <sys/param.h>
40 
41 #include <sys/proc.h>
42 #include <sys/systm.h>
43 #include <sys/bio.h>
44 #include <sys/buf.h>
45 #include <sys/lock.h>
46 #include <sys/ucred.h>
47 #include <sys/vnode.h>
48 
49 #include <fs/ext2fs/inode.h>
50 #include <fs/ext2fs/ext2_extern.h>
51 #include <fs/ext2fs/ext2fs.h>
52 #include <fs/ext2fs/fs.h>
53 
54 #ifdef KDB
55 #include <fs/ext2fs/ext2_mount.h>
56 
57 void	ext2_checkoverlap(struct buf *, struct inode *);
58 #endif
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 bsize, error;
73 
74 	ip = VTOI(vp);
75 	fs = ip->i_e2fs;
76 	lbn = lblkno(fs, offset);
77 	bsize = blksize(fs, ip, lbn);
78 
79 	*bpp = NULL;
80 	if ((error = bread(vp, lbn, bsize, NOCRED, &bp)) != 0) {
81 		brelse(bp);
82 		return (error);
83 	}
84 	if (res)
85 		*res = (char *)bp->b_data + blkoff(fs, offset);
86 	*bpp = bp;
87 	return (0);
88 }
89 
90 #ifdef KDB
91 void
92 ext2_checkoverlap(struct buf *bp, struct inode *ip)
93 {
94 	struct buf *ebp, *ep;
95 	int32_t start, last;
96 	struct vnode *vp;
97 
98 	ebp = &buf[nbuf];
99 	start = bp->b_blkno;
100 	last = start + btodb(bp->b_bcount) - 1;
101 	for (ep = buf; ep < ebp; ep++) {
102 		if (ep == bp || (ep->b_flags & B_INVAL))
103 			continue;
104 		vp = ip->i_ump->um_devvp;
105 		/* look for overlap */
106 		if (ep->b_bcount == 0 || ep->b_blkno > last ||
107 		    ep->b_blkno + btodb(ep->b_bcount) <= start)
108 			continue;
109 		vprint("Disk overlap", vp);
110 		(void)printf("\tstart %d, end %d overlap start %lld, end %ld\n",
111 			start, last, (long long)ep->b_blkno,
112 			(long)(ep->b_blkno + btodb(ep->b_bcount) - 1));
113 		panic("Disk buffer overlap");
114 	}
115 }
116 #endif /* KDB */
117 
118 /*
119  * Update the cluster map because of an allocation of free like ffs.
120  *
121  * Cnt == 1 means free; cnt == -1 means allocating.
122  */
123 void
124 ext2_clusteracct(struct m_ext2fs *fs, char *bbp, int cg, daddr_t bno, int cnt)
125 {
126 	int32_t *sump = fs->e2fs_clustersum[cg].cs_sum;
127 	int32_t *lp;
128 	int back, bit, end, forw, i, loc, start;
129 
130 	/* Initialize the cluster summary array. */
131 	if (fs->e2fs_clustersum[cg].cs_init == 0) {
132 		int run = 0;
133 		bit = 1;
134 		loc = 0;
135 
136 		for (i = 0; i < fs->e2fs->e2fs_fpg; i++) {
137 			if ((bbp[loc] & bit) == 0)
138 				run++;
139 			else if (run != 0) {
140 				if (run > fs->e2fs_contigsumsize)
141 					run = fs->e2fs_contigsumsize;
142 				sump[run]++;
143 				run = 0;
144 			}
145 			if ((i & (NBBY - 1)) != (NBBY - 1))
146 				bit <<= 1;
147 			else {
148 				loc++;
149 				bit = 1;
150 			}
151 		}
152 		if (run != 0) {
153 			if (run > fs->e2fs_contigsumsize)
154 				run = fs->e2fs_contigsumsize;
155 			sump[run]++;
156 		}
157 		fs->e2fs_clustersum[cg].cs_init = 1;
158 	}
159 
160 	if (fs->e2fs_contigsumsize <= 0)
161 		return;
162 
163 	/* Find the size of the cluster going forward. */
164 	start = bno + 1;
165 	end = start + fs->e2fs_contigsumsize;
166 	if (end > fs->e2fs->e2fs_fpg)
167 		end = fs->e2fs->e2fs_fpg;
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)) != (NBBY - 1))
174 			bit <<= 1;
175 		else {
176 			loc++;
177 			bit = 1;
178 		}
179 	}
180 	forw = i - start;
181 
182 	/* Find the size of the cluster going backward. */
183 	start = bno - 1;
184 	end = start - fs->e2fs_contigsumsize;
185 	if (end < 0)
186 		end = -1;
187 	loc = start / NBBY;
188 	bit = 1 << (start % NBBY);
189 	for (i = start; i > end; i--) {
190 		if ((bbp[loc] & bit) != 0)
191 			break;
192 		if ((i & (NBBY - 1)) != 0)
193 			bit >>= 1;
194 		else {
195 			loc--;
196 			bit = 1 << (NBBY - 1);
197 		}
198 	}
199 	back = start - i;
200 
201 	/*
202 	 * Account for old cluster and the possibly new forward and
203 	 * back clusters.
204 	 */
205 	i = back + forw + 1;
206 	if (i > fs->e2fs_contigsumsize)
207 		i = fs->e2fs_contigsumsize;
208 	sump[i] += cnt;
209 	if (back > 0)
210 		sump[back] -= cnt;
211 	if (forw > 0)
212 		sump[forw] -= cnt;
213 
214 	/* Update cluster summary information. */
215 	lp = &sump[fs->e2fs_contigsumsize];
216 	for (i = fs->e2fs_contigsumsize; i > 0; i--)
217 		if (*lp-- > 0)
218 			break;
219 	fs->e2fs_maxcluster[cg] = i;
220 }
221