buf.c revision 1.20
1 /* $NetBSD: buf.c,v 1.20 2013/02/02 20:42:02 christos Exp $ */ 2 3 /* 4 * Copyright (c) 2001 Wasabi Systems, Inc. 5 * All rights reserved. 6 * 7 * Written by Luke Mewburn for Wasabi Systems, Inc. 8 * 9 * Redistribution and use in source and binary forms, with or without 10 * modification, are permitted provided that the following conditions 11 * are met: 12 * 1. Redistributions of source code must retain the above copyright 13 * notice, this list of conditions and the following disclaimer. 14 * 2. Redistributions in binary form must reproduce the above copyright 15 * notice, this list of conditions and the following disclaimer in the 16 * documentation and/or other materials provided with the distribution. 17 * 3. All advertising materials mentioning features or use of this software 18 * must display the following acknowledgement: 19 * This product includes software developed for the NetBSD Project by 20 * Wasabi Systems, Inc. 21 * 4. The name of Wasabi Systems, Inc. may not be used to endorse 22 * or promote products derived from this software without specific prior 23 * written permission. 24 * 25 * THIS SOFTWARE IS PROVIDED BY WASABI SYSTEMS, INC. ``AS IS'' AND 26 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 27 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 28 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL WASABI SYSTEMS, INC 29 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 30 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 31 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 32 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 33 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 34 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 35 * POSSIBILITY OF SUCH DAMAGE. 36 */ 37 38 #if HAVE_NBTOOL_CONFIG_H 39 #include "nbtool_config.h" 40 #endif 41 42 #include <sys/cdefs.h> 43 #if defined(__RCSID) && !defined(__lint) 44 __RCSID("$NetBSD: buf.c,v 1.20 2013/02/02 20:42:02 christos Exp $"); 45 #endif /* !__lint */ 46 47 #include <sys/param.h> 48 #include <sys/time.h> 49 50 #include <assert.h> 51 #include <errno.h> 52 #include <stdio.h> 53 #include <stdlib.h> 54 #include <unistd.h> 55 #include <util.h> 56 57 #include "makefs.h" 58 #include "buf.h" 59 60 TAILQ_HEAD(buftailhead,buf) buftail; 61 62 int 63 bread(struct vnode *vp, daddr_t blkno, int size, struct kauth_cred *u1 __unused, 64 int u2 __unused, struct buf **bpp) 65 { 66 off_t offset; 67 ssize_t rv; 68 fsinfo_t *fs = vp->fs; 69 70 assert (bpp != NULL); 71 72 if (debug & DEBUG_BUF_BREAD) 73 printf("bread: blkno %lld size %d\n", (long long)blkno, size); 74 *bpp = getblk(vp, blkno, size, 0, 0); 75 offset = (*bpp)->b_blkno * fs->sectorsize + fs->offset; 76 if (debug & DEBUG_BUF_BREAD) 77 printf("bread: blkno %lld offset %lld bcount %ld\n", 78 (long long)(*bpp)->b_blkno, (long long) offset, 79 (*bpp)->b_bcount); 80 if (lseek((*bpp)->b_fs->fd, offset, SEEK_SET) == -1) 81 err(1, "bread: lseek %lld (%lld)", 82 (long long)(*bpp)->b_blkno, (long long)offset); 83 rv = read((*bpp)->b_fs->fd, (*bpp)->b_data, (*bpp)->b_bcount); 84 if (debug & DEBUG_BUF_BREAD) 85 printf("bread: read %ld (%lld) returned %d\n", 86 (*bpp)->b_bcount, (long long)offset, (int)rv); 87 if (rv == -1) /* read error */ 88 err(1, "bread: read %ld (%lld) returned %d", 89 (*bpp)->b_bcount, (long long)offset, (int)rv); 90 else if (rv != (*bpp)->b_bcount) /* short read */ 91 err(1, "bread: read %ld (%lld) returned %d", 92 (*bpp)->b_bcount, (long long)offset, (int)rv); 93 else 94 return (0); 95 } 96 97 void 98 brelse(struct buf *bp, int u1 __unused) 99 { 100 101 assert (bp != NULL); 102 assert (bp->b_data != NULL); 103 104 if (bp->b_lblkno < 0) { 105 /* 106 * XXX don't remove any buffers with negative logical block 107 * numbers (lblkno), so that we retain the mapping 108 * of negative lblkno -> real blkno that ffs_balloc() 109 * sets up. 110 * 111 * if we instead released these buffers, and implemented 112 * ufs_strategy() (and ufs_bmaparray()) and called those 113 * from bread() and bwrite() to convert the lblkno to 114 * a real blkno, we'd add a lot more code & complexity 115 * and reading off disk, for little gain, because this 116 * simple hack works for our purpose. 117 */ 118 bp->b_bcount = 0; 119 return; 120 } 121 122 TAILQ_REMOVE(&buftail, bp, b_tailq); 123 free(bp->b_data); 124 free(bp); 125 } 126 127 int 128 bwrite(struct buf *bp) 129 { 130 off_t offset; 131 ssize_t rv; 132 int bytes; 133 fsinfo_t *fs = bp->b_fs; 134 135 assert (bp != NULL); 136 offset = bp->b_blkno * fs->sectorsize + fs->offset; 137 bytes = bp->b_bcount; 138 if (debug & DEBUG_BUF_BWRITE) 139 printf("bwrite: blkno %lld offset %lld bcount %d\n", 140 (long long)bp->b_blkno, (long long) offset, bytes); 141 if (lseek(bp->b_fs->fd, offset, SEEK_SET) == -1) 142 return (errno); 143 rv = write(bp->b_fs->fd, bp->b_data, bytes); 144 if (debug & DEBUG_BUF_BWRITE) 145 printf("bwrite: write %ld (offset %lld) returned %lld\n", 146 bp->b_bcount, (long long)offset, (long long)rv); 147 brelse(bp, 0); 148 if (rv == bytes) 149 return (0); 150 else if (rv == -1) /* write error */ 151 return (errno); 152 else /* short write ? */ 153 return (EAGAIN); 154 } 155 156 void 157 bcleanup(void) 158 { 159 struct buf *bp; 160 161 /* 162 * XXX this really shouldn't be necessary, but i'm curious to 163 * know why there's still some buffers lying around that 164 * aren't brelse()d 165 */ 166 167 if (TAILQ_EMPTY(&buftail)) 168 return; 169 170 printf("bcleanup: unflushed buffers:\n"); 171 TAILQ_FOREACH(bp, &buftail, b_tailq) { 172 printf("\tlblkno %10lld blkno %10lld count %6ld bufsize %6ld\n", 173 (long long)bp->b_lblkno, (long long)bp->b_blkno, 174 bp->b_bcount, bp->b_bufsize); 175 } 176 printf("bcleanup: done\n"); 177 } 178 179 struct buf * 180 getblk(struct vnode *vp, daddr_t blkno, int size, int u1 __unused, 181 int u2 __unused) 182 { 183 static int buftailinitted; 184 struct buf *bp; 185 void *n; 186 187 if (debug & DEBUG_BUF_GETBLK) 188 printf("getblk: blkno %lld size %d\n", (long long)blkno, size); 189 190 bp = NULL; 191 if (!buftailinitted) { 192 if (debug & DEBUG_BUF_GETBLK) 193 printf("getblk: initialising tailq\n"); 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); 214 memset(n, 0, size); 215 bp->b_data = n; 216 bp->b_bufsize = size; 217 } 218 219 return (bp); 220 } 221
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