1 /*
2 * Copyright (c) 1982, 1986, 1989, 1993
3 * The Regents of the University of California. All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
13 * 3. Neither the name of the University nor the names of its contributors
14 * may be used to endorse or promote products derived from this software
15 * without specific prior written permission.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27 * SUCH DAMAGE.
28 *
29 * @(#)ffs_subr.c 8.5 (Berkeley) 3/21/95
30 * $FreeBSD: src/sys/ufs/ffs/ffs_subr.c,v 1.25 1999/12/29 04:55:04 peter Exp $
31 */
32
33 #include <sys/param.h>
34
35 #ifndef _KERNEL
36 #include "dinode.h"
37 #include "fs.h"
38 extern void panic(const char *, ...) __printflike(1, 2) __dead2;
39 #else
40 #include <sys/systm.h>
41 #include <sys/lock.h>
42 #include <sys/vnode.h>
43 #include <sys/buf.h>
44 #include <sys/ucred.h>
45 #include <sys/mount.h>
46
47 #include <sys/buf2.h>
48
49 #include "quota.h"
50 #include "inode.h"
51 #include "fs.h"
52 #include "ffs_extern.h"
53
54 /*
55 * Return buffer with the contents of block "offset" from the beginning of
56 * vnode "vp". If "res" is non-zero, fill it in with a pointer to the
57 * remaining space in the vnode.
58 */
59 int
ffs_blkatoff(struct vnode * vp,off_t uoffset,char ** res,struct buf ** bpp)60 ffs_blkatoff(struct vnode *vp, off_t uoffset, char **res, struct buf **bpp)
61 {
62 struct inode *ip;
63 struct fs *fs;
64 struct buf *bp;
65 ufs_daddr_t lbn;
66 int bsize, error;
67
68 ip = VTOI(vp);
69 fs = ip->i_fs;
70 lbn = lblkno(fs, uoffset);
71 bsize = blksize(fs, ip, lbn);
72
73 *bpp = NULL;
74 error = bread(vp, lblktodoff(fs, lbn), bsize, &bp);
75 if (error) {
76 brelse(bp);
77 return (error);
78 }
79 if (res)
80 *res = (char *)bp->b_data + blkoff(fs, uoffset);
81 *bpp = bp;
82 return (0);
83 }
84
85 /*
86 * Return buffer with the contents of block "offset" from the beginning of
87 * vnode "vp". If "res" is non-zero, fill it in with a pointer to the
88 * remaining space in the vnode.
89 *
90 * This version includes a read-ahead optimization.
91 */
92 int
ffs_blkatoff_ra(struct vnode * vp,off_t uoffset,char ** res,struct buf ** bpp,int seqcount)93 ffs_blkatoff_ra(struct vnode *vp, off_t uoffset, char **res, struct buf **bpp,
94 int seqcount)
95 {
96 struct inode *ip;
97 struct fs *fs;
98 struct buf *bp;
99 ufs_daddr_t lbn;
100 ufs_daddr_t nextlbn;
101 off_t base_loffset;
102 off_t next_loffset;
103 int bsize, error;
104 int nextbsize;
105
106 ip = VTOI(vp);
107 fs = ip->i_fs;
108 lbn = lblkno(fs, uoffset);
109 base_loffset = lblktodoff(fs, lbn);
110 bsize = blksize(fs, ip, lbn);
111
112 nextlbn = lbn + 1;
113 next_loffset = lblktodoff(fs, nextlbn);
114
115
116 *bpp = NULL;
117
118 if (next_loffset >= ip->i_size) {
119 /*
120 * Do not do readahead if this is the last block,
121 * bsize might represent a fragment.
122 */
123 error = bread(vp, base_loffset, bsize, &bp);
124 } else if ((vp->v_mount->mnt_flag & MNT_NOCLUSTERR) == 0) {
125 /*
126 * Try to cluster if we allowed to.
127 */
128 error = cluster_read(vp, (off_t)ip->i_size,
129 base_loffset, bsize,
130 bsize, seqcount * MAXBSIZE, &bp);
131 } else if (seqcount > 1) {
132 /*
133 * Faked read ahead
134 */
135 nextbsize = blksize(fs, ip, nextlbn);
136 error = breadn(vp, base_loffset, bsize,
137 &next_loffset, &nextbsize, 1, &bp);
138 } else {
139 /*
140 * Failing all of the above, just read what the
141 * user asked for. Interestingly, the same as
142 * the first option above.
143 */
144 error = bread(vp, base_loffset, bsize, &bp);
145 }
146 if (error) {
147 brelse(bp);
148 return (error);
149 }
150 if (res)
151 *res = (char *)bp->b_data + (int)(uoffset - base_loffset);
152 *bpp = bp;
153 return (0);
154 }
155
156 #endif
157
158 /*
159 * Update the frsum fields to reflect addition or deletion
160 * of some frags.
161 */
162 void
ffs_fragacct(struct fs * fs,int fragmap,int32_t fraglist[],int cnt)163 ffs_fragacct(struct fs *fs, int fragmap, int32_t fraglist[], int cnt)
164 {
165 int inblk;
166 int field, subfield;
167 int siz, pos;
168
169 /*
170 * inblk represents a bitmap of fragment sizes which may be
171 * contained in the data 'fragmap'. e.g. if a fragment of size
172 * 1 is available, bit 0 would be set. inblk is shifted left
173 * by one so we do not have to calculate (1 << (siz - 1)).
174 *
175 * fragment represents the data pattern we are trying to decipher,
176 * we shift it left by one to align it with the 'around' and 'inside'
177 * masks.
178 *
179 * around represents the bits around the subfield and is a mask.
180 * inside represents what we must match within the mask, it is
181 * basically the mask with the first and last bit set to 0, allowing
182 * us to represent a whole fragment.
183 *
184 * When we find a match we bump our position by the size of the
185 * matching fragment, then bump the position again:
186 *
187 * 010101010 fragmap (shifted left by 1)
188 * 111 around mask
189 * 010 inside mask
190 * 111 (shifted by siz)
191 * 010
192 * 111 (shifted again)
193 * 010
194 */
195 inblk = (int)(fragtbl[fs->fs_frag][fragmap]) << 1;
196 fragmap <<= 1;
197 for (siz = 1; siz < fs->fs_frag; siz++) {
198 if ((inblk & (1 << (siz + (fs->fs_frag % NBBY)))) == 0)
199 continue;
200 field = around[siz];
201 subfield = inside[siz];
202 for (pos = siz; pos <= fs->fs_frag; pos++) {
203 if ((fragmap & field) == subfield) {
204 fraglist[siz] += cnt;
205 pos += siz;
206 field <<= siz;
207 subfield <<= siz;
208 }
209 field <<= 1;
210 subfield <<= 1;
211 }
212 }
213 }
214
215 /*
216 * block operations
217 *
218 * check if a block is available
219 */
220 int
ffs_isblock(struct fs * fs,unsigned char * cp,ufs_daddr_t h)221 ffs_isblock(struct fs *fs, unsigned char *cp, ufs_daddr_t h)
222 {
223 unsigned char mask;
224
225 switch ((int)fs->fs_frag) {
226 case 8:
227 return (cp[h] == 0xff);
228 case 4:
229 mask = 0x0f << ((h & 0x1) << 2);
230 return ((cp[h >> 1] & mask) == mask);
231 case 2:
232 mask = 0x03 << ((h & 0x3) << 1);
233 return ((cp[h >> 2] & mask) == mask);
234 case 1:
235 mask = 0x01 << (h & 0x7);
236 return ((cp[h >> 3] & mask) == mask);
237 default:
238 panic("ffs_isblock");
239 }
240 }
241
242 /*
243 * check if a block is free
244 */
245 int
ffs_isfreeblock(struct fs * fs,unsigned char * cp,ufs_daddr_t h)246 ffs_isfreeblock(struct fs *fs, unsigned char *cp, ufs_daddr_t h)
247 {
248 switch ((int)fs->fs_frag) {
249 case 8:
250 return (cp[h] == 0);
251 case 4:
252 return ((cp[h >> 1] & (0x0f << ((h & 0x1) << 2))) == 0);
253 case 2:
254 return ((cp[h >> 2] & (0x03 << ((h & 0x3) << 1))) == 0);
255 case 1:
256 return ((cp[h >> 3] & (0x01 << (h & 0x7))) == 0);
257 default:
258 panic("ffs_isfreeblock");
259 }
260 }
261
262 /*
263 * take a block out of the map
264 */
265 void
ffs_clrblock(struct fs * fs,u_char * cp,ufs_daddr_t h)266 ffs_clrblock(struct fs *fs, u_char *cp, ufs_daddr_t h)
267 {
268 switch ((int)fs->fs_frag) {
269 case 8:
270 cp[h] = 0;
271 return;
272 case 4:
273 cp[h >> 1] &= ~(0x0f << ((h & 0x1) << 2));
274 return;
275 case 2:
276 cp[h >> 2] &= ~(0x03 << ((h & 0x3) << 1));
277 return;
278 case 1:
279 cp[h >> 3] &= ~(0x01 << (h & 0x7));
280 return;
281 default:
282 panic("ffs_clrblock");
283 }
284 }
285
286 /*
287 * put a block into the map
288 */
289 void
ffs_setblock(struct fs * fs,unsigned char * cp,ufs_daddr_t h)290 ffs_setblock(struct fs *fs, unsigned char *cp, ufs_daddr_t h)
291 {
292 switch ((int)fs->fs_frag) {
293 case 8:
294 cp[h] = 0xff;
295 return;
296 case 4:
297 cp[h >> 1] |= (0x0f << ((h & 0x1) << 2));
298 return;
299 case 2:
300 cp[h >> 2] |= (0x03 << ((h & 0x3) << 1));
301 return;
302 case 1:
303 cp[h >> 3] |= (0x01 << (h & 0x7));
304 return;
305 default:
306 panic("ffs_setblock");
307 }
308 }
309