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1.1 root 1: /*
2: * Copyright (c) 1982, 1986, 1989 Regents of the University of California.
3: * 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. All advertising materials mentioning features or use of this software
14: * must display the following acknowledgement:
15: * This product includes software developed by the University of
16: * California, Berkeley and its contributors.
17: * 4. Neither the name of the University nor the names of its contributors
18: * may be used to endorse or promote products derived from this software
19: * without specific prior written permission.
20: *
21: * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
22: * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23: * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24: * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
25: * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26: * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27: * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28: * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29: * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30: * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31: * SUCH DAMAGE.
32: *
33: * from: @(#)vfs_bio.c 7.40 (Berkeley) 5/8/91
34: */
35:
36: #include "param.h"
37: #include "proc.h"
38: #include "buf.h"
39: #include "vnode.h"
40: #include "specdev.h"
41: #include "mount.h"
42: #include "trace.h"
43: #include "resourcevar.h"
44:
45: /*
46: * Initialize buffers and hash links for buffers.
47: */
48: bufinit()
49: {
50:
51: /*
52: * Body deleted.
53: */
54: return;
55: }
56:
57: /*
58: * Find the block in the buffer pool.
59: * If the buffer is not present, allocate a new buffer and load
60: * its contents according to the filesystem fill routine.
61: */
62: bread(vp, blkno, size, cred, bpp)
63: struct vnode *vp;
64: daddr_t blkno;
65: int size;
66: struct ucred *cred;
67: struct buf **bpp;
68: {
69:
70: /*
71: * Body deleted.
72: */
73: return (EIO);
74: }
75:
76: /*
77: * Operates like bread, but also starts I/O on the specified
78: * read-ahead block.
79: */
80: breada(vp, blkno, size, rablkno, rabsize, cred, bpp)
81: struct vnode *vp;
82: daddr_t blkno; int size;
83: daddr_t rablkno; int rabsize;
84: struct ucred *cred;
85: struct buf **bpp;
86: {
87:
88: /*
89: * Body deleted.
90: */
91: return (EIO);
92: }
93:
94: /*
95: * Synchronous write.
96: * Release buffer on completion.
97: */
98: bwrite(bp)
99: register struct buf *bp;
100: {
101:
102: /*
103: * Body deleted.
104: */
105: return (EIO);
106: }
107:
108: /*
109: * Delayed write.
110: *
111: * The buffer is marked dirty, but is not queued for I/O.
112: * This routine should be used when the buffer is expected
113: * to be modified again soon, typically a small write that
114: * partially fills a buffer.
115: *
116: * NB: magnetic tapes cannot be delayed; they must be
117: * written in the order that the writes are requested.
118: */
119: bdwrite(bp)
120: register struct buf *bp;
121: {
122:
123: /*
124: * Body deleted.
125: */
126: return;
127: }
128:
129: /*
130: * Asynchronous write.
131: * Start I/O on a buffer, but do not wait for it to complete.
132: * The buffer is released when the I/O completes.
133: */
134: bawrite(bp)
135: register struct buf *bp;
136: {
137:
138: /*
139: * Body deleted.
140: */
141: return;
142: }
143:
144: /*
145: * Release a buffer.
146: * Even if the buffer is dirty, no I/O is started.
147: */
148: brelse(bp)
149: register struct buf *bp;
150: {
151:
152: /*
153: * Body deleted.
154: */
155: return;
156: }
157:
158: /*
159: * Check to see if a block is currently memory resident.
160: */
161: incore(vp, blkno)
162: struct vnode *vp;
163: daddr_t blkno;
164: {
165:
166: /*
167: * Body deleted.
168: */
169: return (0);
170: }
171:
172: /*
173: * Check to see if a block is currently memory resident.
174: * If it is resident, return it. If it is not resident,
175: * allocate a new buffer and assign it to the block.
176: */
177: struct buf *
178: getblk(vp, blkno, size)
179: register struct vnode *vp;
180: daddr_t blkno;
181: int size;
182: {
183:
184: /*
185: * Body deleted.
186: */
187: return (0);
188: }
189:
190: /*
191: * Allocate a buffer.
192: * The caller will assign it to a block.
193: */
194: struct buf *
195: geteblk(size)
196: int size;
197: {
198:
199: /*
200: * Body deleted.
201: */
202: return (0);
203: }
204:
205: /*
206: * Expand or contract the actual memory allocated to a buffer.
207: * If no memory is available, release buffer and take error exit.
208: */
209: allocbuf(tp, size)
210: register struct buf *tp;
211: int size;
212: {
213:
214: /*
215: * Body deleted.
216: */
217: return (0);
218: }
219:
220: /*
221: * Find a buffer which is available for use.
222: * Select something from a free list.
223: * Preference is to AGE list, then LRU list.
224: */
225: struct buf *
226: getnewbuf()
227: {
228:
229: /*
230: * Body deleted.
231: */
232: return (0);
233: }
234:
235: /*
236: * Wait for I/O to complete.
237: *
238: * Extract and return any errors associated with the I/O.
239: * If the error flag is set, but no specific error is
240: * given, return EIO.
241: */
242: biowait(bp)
243: register struct buf *bp;
244: {
245:
246: /*
247: * Body deleted.
248: */
249: return (EIO);
250: }
251:
252: /*
253: * Mark I/O complete on a buffer.
254: *
255: * If a callback has been requested, e.g. the pageout
256: * daemon, do so. Otherwise, awaken waiting processes.
257: */
258: biodone(bp)
259: register struct buf *bp;
260: {
261:
262: /*
263: * Body deleted.
264: */
265: return;
266: }
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