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/cdefs.h> 41 #include <sys/param.h> 42 #include <sys/time.h> 43 44 #include <assert.h> 45 #include <errno.h> 46 #include <stdio.h> 47 #include <stdlib.h> 48 #include <string.h> 49 #include <unistd.h> 50 #include <util.h> 51 52 #include "makefs.h" 53 #include "buf.h" 54 55 static TAILQ_HEAD(buftailhead, m_buf) buftail; 56 57 int 58 bread(struct m_vnode *vp, daddr_t blkno, int size, struct ucred *u1 __unused, 59 struct m_buf **bpp) 60 { 61 off_t offset; 62 ssize_t rv; 63 fsinfo_t *fs = vp->fs; 64 65 assert (bpp != NULL); 66 67 if (debug & DEBUG_BUF_BREAD) 68 printf("%s: blkno %lld size %d\n", __func__, (long long)blkno, 69 size); 70 *bpp = getblk(vp, blkno, size, 0, 0, 0); 71 offset = (off_t)(*bpp)->b_blkno * fs->sectorsize + fs->offset; 72 if (debug & DEBUG_BUF_BREAD) 73 printf("%s: blkno %lld offset %lld bcount %ld\n", __func__, 74 (long long)(*bpp)->b_blkno, (long long) offset, 75 (*bpp)->b_bcount); 76 if (lseek((*bpp)->b_fs->fd, offset, SEEK_SET) == -1) 77 err(1, "%s: lseek %lld (%lld)", __func__, 78 (long long)(*bpp)->b_blkno, (long long)offset); 79 rv = read((*bpp)->b_fs->fd, (*bpp)->b_data, (size_t)(*bpp)->b_bcount); 80 if (debug & DEBUG_BUF_BREAD) 81 printf("%s: read %ld (%lld) returned %d\n", __func__, 82 (*bpp)->b_bcount, (long long)offset, (int)rv); 83 if (rv == -1) /* read error */ 84 err(1, "%s: read %ld (%lld) returned %d", __func__, 85 (*bpp)->b_bcount, (long long)offset, (int)rv); 86 else if (rv != (*bpp)->b_bcount) /* short read */ 87 err(1, "%s: read %ld (%lld) returned %d", __func__, 88 (*bpp)->b_bcount, (long long)offset, (int)rv); 89 else 90 return (0); 91 } 92 93 void 94 brelse(struct m_buf *bp) 95 { 96 97 assert (bp != NULL); 98 assert (bp->b_data != NULL); 99 100 if (bp->b_lblkno < 0) { 101 /* 102 * XXX don't remove any buffers with negative logical block 103 * numbers (lblkno), so that we retain the mapping 104 * of negative lblkno -> real blkno that ffs_balloc() 105 * sets up. 106 * 107 * if we instead released these buffers, and implemented 108 * ufs_strategy() (and ufs_bmaparray()) and called those 109 * from bread() and bwrite() to convert the lblkno to 110 * a real blkno, we'd add a lot more code & complexity 111 * and reading off disk, for little gain, because this 112 * simple hack works for our purpose. 113 */ 114 bp->b_bcount = 0; 115 return; 116 } 117 118 TAILQ_REMOVE(&buftail, bp, b_tailq); 119 free(bp->b_data); 120 free(bp); 121 } 122 123 int 124 bwrite(struct m_buf *bp) 125 { 126 off_t offset; 127 ssize_t rv; 128 size_t bytes; 129 int e; 130 fsinfo_t *fs = bp->b_fs; 131 132 assert (bp != NULL); 133 offset = (off_t)bp->b_blkno * fs->sectorsize + fs->offset; 134 bytes = (size_t)bp->b_bcount; 135 if (debug & DEBUG_BUF_BWRITE) 136 printf("%s: blkno %lld offset %lld bcount %zu\n", __func__, 137 (long long)bp->b_blkno, (long long) offset, bytes); 138 if (lseek(bp->b_fs->fd, offset, SEEK_SET) == -1) { 139 brelse(bp); 140 return (errno); 141 } 142 rv = write(bp->b_fs->fd, bp->b_data, bytes); 143 e = errno; 144 if (debug & DEBUG_BUF_BWRITE) 145 printf("%s: write %ld (offset %lld) returned %lld\n", __func__, 146 bp->b_bcount, (long long)offset, (long long)rv); 147 brelse(bp); 148 if (rv == (ssize_t)bytes) 149 return (0); 150 if (rv == -1) /* write error */ 151 return (e); 152 return (EAGAIN); 153 } 154 155 void 156 bcleanup(void) 157 { 158 struct m_buf *bp; 159 160 /* 161 * XXX this really shouldn't be necessary, but i'm curious to 162 * know why there's still some buffers lying around that 163 * aren't brelse()d 164 */ 165 166 if (TAILQ_EMPTY(&buftail)) 167 return; 168 169 printf("%s: unflushed buffers:\n", __func__); 170 TAILQ_FOREACH(bp, &buftail, b_tailq) { 171 printf("\tlblkno %10lld blkno %10lld count %6ld bufsize %6ld\n", 172 (long long)bp->b_lblkno, (long long)bp->b_blkno, 173 bp->b_bcount, bp->b_bufsize); 174 } 175 printf("%s: done\n", __func__); 176 } 177 178 struct m_buf * 179 getblk(struct m_vnode *vp, daddr_t blkno, int size, int u1 __unused, 180 int u2 __unused, int u3 __unused) 181 { 182 static int buftailinitted; 183 struct m_buf *bp; 184 void *n; 185 186 if (debug & DEBUG_BUF_GETBLK) 187 printf("%s: blkno %lld size %d\n", __func__, (long long)blkno, 188 size); 189 190 bp = NULL; 191 if (!buftailinitted) { 192 if (debug & DEBUG_BUF_GETBLK) 193 printf("%s: initialising tailq\n", __func__); 194 TAILQ_INIT(&buftail); 195 buftailinitted = 1; 196 } else { 197 TAILQ_FOREACH(bp, &buftail, b_tailq) { 198 if (bp->b_lblkno != blkno) 199 continue; 200 break; 201 } 202 } 203 if (bp == NULL) { 204 bp = ecalloc(1, sizeof(*bp)); 205 bp->b_bufsize = 0; 206 bp->b_blkno = bp->b_lblkno = blkno; 207 bp->b_fs = vp->fs; 208 bp->b_data = NULL; 209 TAILQ_INSERT_HEAD(&buftail, bp, b_tailq); 210 } 211 bp->b_bcount = size; 212 if (bp->b_data == NULL || bp->b_bcount > bp->b_bufsize) { 213 n = erealloc(bp->b_data, (size_t)size); 214 memset(n, 0, (size_t)size); 215 bp->b_data = n; 216 bp->b_bufsize = size; 217 } 218 219 return (bp); 220 } 221