1 /* $NetBSD: buf.c,v 1.13 2004/06/20 22:20:18 jmc Exp $ */
2
3 /*-
4 * SPDX-License-Identifier: BSD-4-Clause
5 *
6 * Copyright (c) 2001 Wasabi Systems, Inc.
7 * All rights reserved.
8 *
9 * Written by Luke Mewburn for Wasabi Systems, Inc.
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 * 3. All advertising materials mentioning features or use of this software
20 * must display the following acknowledgement:
21 * This product includes software developed for the NetBSD Project by
22 * Wasabi Systems, Inc.
23 * 4. The name of Wasabi Systems, Inc. may not be used to endorse
24 * or promote products derived from this software without specific prior
25 * written permission.
26 *
27 * THIS SOFTWARE IS PROVIDED BY WASABI SYSTEMS, INC. ``AS IS'' AND
28 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
29 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
30 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL WASABI SYSTEMS, INC
31 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
32 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
33 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
34 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
35 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
36 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
37 * POSSIBILITY OF SUCH DAMAGE.
38 */
39
40 #include <sys/param.h>
41 #include <sys/time.h>
42
43 #include <assert.h>
44 #include <errno.h>
45 #include <stdio.h>
46 #include <stdlib.h>
47 #include <string.h>
48 #include <unistd.h>
49 #include <util.h>
50
51 #include "makefs.h"
52 #include "buf.h"
53
54 static TAILQ_HEAD(buftailhead, m_buf) buftail;
55
56 int
bread(struct m_vnode * vp,daddr_t blkno,int size,struct ucred * u1 __unused,struct m_buf ** bpp)57 bread(struct m_vnode *vp, daddr_t blkno, int size, struct ucred *u1 __unused,
58 struct m_buf **bpp)
59 {
60 off_t offset;
61 ssize_t rv;
62 fsinfo_t *fs = vp->fs;
63
64 assert (bpp != NULL);
65
66 if (debug & DEBUG_BUF_BREAD)
67 printf("%s: blkno %lld size %d\n", __func__, (long long)blkno,
68 size);
69 *bpp = getblk(vp, blkno, size, 0, 0, 0);
70 offset = (off_t)(*bpp)->b_blkno * fs->sectorsize + fs->offset;
71 if (debug & DEBUG_BUF_BREAD)
72 printf("%s: blkno %lld offset %lld bcount %ld\n", __func__,
73 (long long)(*bpp)->b_blkno, (long long) offset,
74 (*bpp)->b_bcount);
75 if (lseek((*bpp)->b_fs->fd, offset, SEEK_SET) == -1)
76 err(1, "%s: lseek %lld (%lld)", __func__,
77 (long long)(*bpp)->b_blkno, (long long)offset);
78 rv = read((*bpp)->b_fs->fd, (*bpp)->b_data, (size_t)(*bpp)->b_bcount);
79 if (debug & DEBUG_BUF_BREAD)
80 printf("%s: read %ld (%lld) returned %d\n", __func__,
81 (*bpp)->b_bcount, (long long)offset, (int)rv);
82 if (rv == -1) /* read error */
83 err(1, "%s: read %ld (%lld) returned %d", __func__,
84 (*bpp)->b_bcount, (long long)offset, (int)rv);
85 else if (rv != (*bpp)->b_bcount) /* short read */
86 err(1, "%s: read %ld (%lld) returned %d", __func__,
87 (*bpp)->b_bcount, (long long)offset, (int)rv);
88 else
89 return (0);
90 }
91
92 void
brelse(struct m_buf * bp)93 brelse(struct m_buf *bp)
94 {
95
96 assert (bp != NULL);
97 assert (bp->b_data != NULL);
98
99 if (bp->b_lblkno < 0) {
100 /*
101 * XXX don't remove any buffers with negative logical block
102 * numbers (lblkno), so that we retain the mapping
103 * of negative lblkno -> real blkno that ffs_balloc()
104 * sets up.
105 *
106 * if we instead released these buffers, and implemented
107 * ufs_strategy() (and ufs_bmaparray()) and called those
108 * from bread() and bwrite() to convert the lblkno to
109 * a real blkno, we'd add a lot more code & complexity
110 * and reading off disk, for little gain, because this
111 * simple hack works for our purpose.
112 */
113 bp->b_bcount = 0;
114 return;
115 }
116
117 TAILQ_REMOVE(&buftail, bp, b_tailq);
118 free(bp->b_data);
119 free(bp);
120 }
121
122 int
bwrite(struct m_buf * bp)123 bwrite(struct m_buf *bp)
124 {
125 off_t offset;
126 ssize_t rv;
127 size_t bytes;
128 int e;
129 fsinfo_t *fs = bp->b_fs;
130
131 assert (bp != NULL);
132 offset = (off_t)bp->b_blkno * fs->sectorsize + fs->offset;
133 bytes = (size_t)bp->b_bcount;
134 if (debug & DEBUG_BUF_BWRITE)
135 printf("%s: blkno %lld offset %lld bcount %zu\n", __func__,
136 (long long)bp->b_blkno, (long long) offset, bytes);
137 if (lseek(bp->b_fs->fd, offset, SEEK_SET) == -1) {
138 brelse(bp);
139 return (errno);
140 }
141 rv = write(bp->b_fs->fd, bp->b_data, bytes);
142 e = errno;
143 if (debug & DEBUG_BUF_BWRITE)
144 printf("%s: write %ld (offset %lld) returned %lld\n", __func__,
145 bp->b_bcount, (long long)offset, (long long)rv);
146 brelse(bp);
147 if (rv == (ssize_t)bytes)
148 return (0);
149 if (rv == -1) /* write error */
150 return (e);
151 return (EAGAIN);
152 }
153
154 void
bcleanup(void)155 bcleanup(void)
156 {
157 struct m_buf *bp;
158
159 /*
160 * XXX this really shouldn't be necessary, but i'm curious to
161 * know why there's still some buffers lying around that
162 * aren't brelse()d
163 */
164
165 if (TAILQ_EMPTY(&buftail))
166 return;
167
168 printf("%s: unflushed buffers:\n", __func__);
169 TAILQ_FOREACH(bp, &buftail, b_tailq) {
170 printf("\tlblkno %10lld blkno %10lld count %6ld bufsize %6ld\n",
171 (long long)bp->b_lblkno, (long long)bp->b_blkno,
172 bp->b_bcount, bp->b_bufsize);
173 }
174 printf("%s: done\n", __func__);
175 }
176
177 struct m_buf *
getblk(struct m_vnode * vp,daddr_t blkno,int size,int u1 __unused,int u2 __unused,int u3 __unused)178 getblk(struct m_vnode *vp, daddr_t blkno, int size, int u1 __unused,
179 int u2 __unused, int u3 __unused)
180 {
181 static int buftailinitted;
182 struct m_buf *bp;
183 void *n;
184
185 if (debug & DEBUG_BUF_GETBLK)
186 printf("%s: blkno %lld size %d\n", __func__, (long long)blkno,
187 size);
188
189 bp = NULL;
190 if (!buftailinitted) {
191 if (debug & DEBUG_BUF_GETBLK)
192 printf("%s: initialising tailq\n", __func__);
193 TAILQ_INIT(&buftail);
194 buftailinitted = 1;
195 } else {
196 TAILQ_FOREACH(bp, &buftail, b_tailq) {
197 if (bp->b_lblkno != blkno)
198 continue;
199 break;
200 }
201 }
202 if (bp == NULL) {
203 bp = ecalloc(1, sizeof(*bp));
204 bp->b_bufsize = 0;
205 bp->b_blkno = bp->b_lblkno = blkno;
206 bp->b_fs = vp->fs;
207 bp->b_data = NULL;
208 TAILQ_INSERT_HEAD(&buftail, bp, b_tailq);
209 }
210 bp->b_bcount = size;
211 if (bp->b_data == NULL || bp->b_bcount > bp->b_bufsize) {
212 n = erealloc(bp->b_data, (size_t)size);
213 memset(n, 0, (size_t)size);
214 bp->b_data = n;
215 bp->b_bufsize = size;
216 }
217
218 return (bp);
219 }
220