buf.c revision 1.6 
1/*	$OpenBSD: buf.c,v 1.6 2016/12/17 16:26:46 krw Exp $	*/
2/*	$NetBSD: buf.c,v 1.24 2016/06/24 19:24:11 christos Exp $	*/
3
4/*
5 * Copyright (c) 2001 Wasabi Systems, Inc.
6 * All rights reserved.
7 *
8 * Written by Luke Mewburn for Wasabi Systems, Inc.
9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
13 * 1. Redistributions of source code must retain the above copyright
14 *    notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 *    notice, this list of conditions and the following disclaimer in the
17 *    documentation and/or other materials provided with the distribution.
18 * 3. All advertising materials mentioning features or use of this software
19 *    must display the following acknowledgement:
20 *      This product includes software developed for the NetBSD Project by
21 *      Wasabi Systems, Inc.
22 * 4. The name of Wasabi Systems, Inc. may not be used to endorse
23 *    or promote products derived from this software without specific prior
24 *    written permission.
25 *
26 * THIS SOFTWARE IS PROVIDED BY WASABI SYSTEMS, INC. ``AS IS'' AND
27 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
28 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
29 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL WASABI SYSTEMS, INC
30 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
31 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
32 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
33 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
34 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
35 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
36 * POSSIBILITY OF SUCH DAMAGE.
37 */
38
39#include <sys/param.h>
40#include <sys/time.h>
41
42#include <assert.h>
43#include <errno.h>
44#include <stdio.h>
45#include <stdlib.h>
46#include <unistd.h>
47#include <util.h>
48
49#include "makefs.h"
50#include "buf.h"
51
52TAILQ_HEAD(buftailhead,mkfsbuf) buftail;
53
54int
55bread(struct mkfsvnode *vp, daddr_t blkno, int size, int u2 __unused,
56	struct mkfsbuf **bpp)
57{
58	off_t	offset;
59	ssize_t	rv;
60	fsinfo_t *fs = vp->fs;
61
62	assert (bpp != NULL);
63
64	*bpp = getblk(vp, blkno, size, 0, 0);
65	offset = (*bpp)->b_blkno * fs->sectorsize + fs->offset;
66	if (lseek((*bpp)->b_fs->fd, offset, SEEK_SET) == -1)
67		err(1, "%s: lseek %lld (%lld)", __func__,
68		    (long long)(*bpp)->b_blkno, (long long)offset);
69	rv = read((*bpp)->b_fs->fd, (*bpp)->b_data, (size_t)(*bpp)->b_bcount);
70	if (rv == -1)				/* read error */
71		err(1, "%s: read %ld (%lld) returned %zd", __func__,
72		    (*bpp)->b_bcount, (long long)offset, rv);
73	else if (rv != (*bpp)->b_bcount)	/* short read */
74		errx(1, "%s: read %ld (%lld) returned %zd", __func__,
75		    (*bpp)->b_bcount, (long long)offset, rv);
76	else
77		return (0);
78}
79
80void
81brelse(struct mkfsbuf *bp, int u1 __unused)
82{
83
84	assert (bp != NULL);
85	assert (bp->b_data != NULL);
86
87	if (bp->b_lblkno < 0) {
88		/*
89		 * XXX	don't remove any buffers with negative logical block
90		 *	numbers (lblkno), so that we retain the mapping
91		 *	of negative lblkno -> real blkno that ffs_balloc()
92		 *	sets up.
93		 *
94		 *	if we instead released these buffers, and implemented
95		 *	ufs_strategy() (and ufs_bmaparray()) and called those
96		 *	from bread() and bwrite() to convert the lblkno to
97		 *	a real blkno, we'd add a lot more code & complexity
98		 *	and reading off disk, for little gain, because this
99		 *	simple hack works for our purpose.
100		 */
101		bp->b_bcount = 0;
102		return;
103	}
104
105	TAILQ_REMOVE(&buftail, bp, b_tailq);
106	free(bp->b_data);
107	free(bp);
108}
109
110int
111bwrite(struct mkfsbuf *bp)
112{
113	off_t	offset;
114	ssize_t	rv;
115	size_t	bytes;
116	fsinfo_t *fs = bp->b_fs;
117
118	assert (bp != NULL);
119	offset = bp->b_blkno * fs->sectorsize + fs->offset;
120	bytes  = (size_t)bp->b_bcount;
121	if (lseek(bp->b_fs->fd, offset, SEEK_SET) == -1)
122		return (errno);
123	rv = write(bp->b_fs->fd, bp->b_data, bytes);
124	brelse(bp, 0);
125	if (rv == (ssize_t)bytes)
126		return (0);
127	else if (rv == -1)		/* write error */
128		return (errno);
129	else				/* short write ? */
130		return (EAGAIN);
131}
132
133void
134bcleanup(void)
135{
136#if DEBUG_BUFFERS
137	struct mkfsbuf *bp;
138
139	/*
140	 * XXX	this really shouldn't be necessary, but i'm curious to
141	 *	know why there's still some buffers lying around that
142	 *	aren't brelse()d
143	 */
144
145	if (TAILQ_EMPTY(&buftail))
146		return;
147
148	printf("bcleanup: unflushed buffers:\n");
149	TAILQ_FOREACH(bp, &buftail, b_tailq) {
150		printf("\tlblkno %10lld  blkno %10lld  count %6ld  bufsize %6ld\n",
151		    (long long)bp->b_lblkno, (long long)bp->b_blkno,
152		    bp->b_bcount, bp->b_bufsize);
153	}
154	printf("bcleanup: done\n");
155#endif
156}
157
158struct mkfsbuf *
159getblk(struct mkfsvnode *vp, daddr_t blkno, int size, int u1 __unused,
160    int u2 __unused)
161{
162	static int buftailinitted;
163	struct mkfsbuf *bp;
164	void *n;
165
166	bp = NULL;
167	if (!buftailinitted) {
168		TAILQ_INIT(&buftail);
169		buftailinitted = 1;
170	} else {
171		TAILQ_FOREACH(bp, &buftail, b_tailq) {
172			if (bp->b_lblkno != blkno)
173				continue;
174			break;
175		}
176	}
177	if (bp == NULL) {
178		bp = ecalloc(1, sizeof(*bp));
179		bp->b_bufsize = 0;
180		bp->b_blkno = bp->b_lblkno = blkno;
181		bp->b_fs = vp->fs;
182		bp->b_data = NULL;
183		TAILQ_INSERT_HEAD(&buftail, bp, b_tailq);
184	}
185	bp->b_bcount = size;
186	if (bp->b_data == NULL || bp->b_bcount > bp->b_bufsize) {
187		n = erealloc(bp->b_data, (size_t)size);
188		memset(n, 0, (size_t)size);
189		bp->b_data = n;
190		bp->b_bufsize = size;
191	}
192
193	return (bp);
194}
195