xref: /haiku/src/add-ons/kernel/file_systems/fat/bsd/sys/bufobj.h (revision 909af08f4328301fbdef1ffb41f566c3b5bec0c7)
1 /*-
2  * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
3  *
4  * Copyright (c) 2004 Poul-Henning Kamp
5  * All rights reserved.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  * 1. Redistributions of source code must retain the above copyright
11  *    notice, this list of conditions and the following disclaimer.
12  * 2. Redistributions in binary form must reproduce the above copyright
13  *    notice, this list of conditions and the following disclaimer in the
14  *    documentation and/or other materials provided with the distribution.
15  *
16  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
17  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
20  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26  * SUCH DAMAGE.
27  */
28 #ifndef FAT_BUFOBJ_H
29 #define FAT_BUFOBJ_H
30 
31 
32 // Modified to support the Haiku FAT driver.
33 
34 #include <sys/queue.h>
35 
36 #include "sys/_rwlock.h"
37 
38 
39 SLIST_HEAD(buf_list, buf);
40 
41 // For the device vnode, v_bufobj holds lists of struct bufs that are available for use
42 // by the functions defined in vfs_bio.c. For all other nodes, v_bufobj is not used.
43 struct bufobj {
44 	struct rwlock bo_lock;
45 	u_int bo_flag;
46 
47 	// Members added for Haiku port
48 	struct buf_list bo_clusterbufs;
49 		// an SLIST of buffers with b_bufsize equal to cluster size
50 	uint32 bo_clusters;
51 		// count of bufs in bo_clusterbufs
52 	struct buf_list bo_fatbufs;
53 		// SLIST of buffers of the size used to read the FAT. Currently, FAT16 and FAT32 volumes
54 		// read the FAT in 512-byte blocks, and this is only useful for FAT12, which reads it in
55 		// 1536-byte blocks.
56 	uint32 bo_fatblocks;
57 	struct buf_list bo_emptybufs;
58 		// SLIST of buffers with no space allocated for b_data (b_data must be set to point to a
59 		// block in the block cache).
60 	uint32 bo_empties;
61 };
62 
63 #define BO_LOCK(bo) rw_lock_write_lock(BO_LOCKPTR(bo))
64 #define BO_UNLOCK(bo) rw_lock_write_unlock(BO_LOCKPTR(bo))
65 
66 
67 #endif // FAT_BUFOBJ_H
68