bufobj.h revision 137033 
1/*-
2 * Copyright (c) 2004 Poul-Henning Kamp
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 *
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24 * SUCH DAMAGE.
25 *
26 * $FreeBSD: head/sys/sys/bufobj.h 137033 2004-10-29 09:33:32Z phk $
27 */
28
29/*
30 * Architectural notes:
31 *
32 * bufobj is a new object which is what buffers hang from in the buffer
33 * cache.
34 *
35 * This used to be vnodes, but we need non-vnode code to be able
36 * to use the buffer cache as well, specifically geom classes like gbde,
37 * raid3 and raid5.
38 *
39 * All vnodes will contain a bufobj initially, but down the road we may
40 * want to only allocate bufobjs when they are needed.  There could be a
41 * large number of vnodes in the system which wouldn't need a bufobj during
42 * their lifetime.
43 *
44 * The exact relationship to the vmobject is not determined at this point,
45 * it may in fact bee that we find them to be two sides of the same object
46 * once things starts to crystalize.
47 */
48
49#ifndef _SYS_BUFOBJ_H_
50#define _SYS_BUFOBJ_H_
51
52#if defined(_KERNEL) || defined(_KVM_VNODE)
53
54#include <sys/queue.h>
55
56struct bufobj;
57struct buf_ops;
58
59extern struct buf_ops buf_ops_bio;
60
61TAILQ_HEAD(buflists, buf);
62
63/* A Buffer splay list */
64struct bufv {
65	struct buflists	bv_hd;		/* Sorted blocklist */
66	struct buf	*bv_root;	/* Buf splay tree */
67	int		bv_cnt;		/* Number of buffers */
68};
69
70typedef void b_strategy_t(struct bufobj *, struct buf *);
71typedef int b_write_t(struct buf *);
72
73struct buf_ops {
74	char		*bop_name;
75	b_write_t	*bop_write;
76	b_strategy_t	*bop_strategy;
77};
78
79struct bufobj {
80	struct mtx	*bo_mtx;	/* Mutex which protects "i" things */
81	struct bufv	bo_clean;	/* i Clean buffers */
82	struct bufv	bo_dirty;	/* i Dirty buffers */
83	long		bo_numoutput;	/* i Writes in progress */
84	u_int		bo_flag;	/* i Flags */
85	struct buf_ops	*bo_ops;	/* - Buffer operations */
86	int		bo_bsize;	/* - Block size for i/o */
87	struct vm_object *bo_object;	/* v Place to store VM object */
88	LIST_ENTRY(bufobj) bo_synclist;	/* S dirty vnode list */
89	void		*bo_private;	/* private pointer */
90	struct vnode	*__bo_vnode;	/*
91					 * XXX: This vnode pointer is here
92					 * XXX: only to keep the syncer working
93					 * XXX: for now.
94					 */
95};
96
97/*
98 * XXX BO_ONWORKLST could be replaced with a check for NULL list elements
99 * in v_synclist.
100 */
101#define	BO_ONWORKLST	(1 << 0)	/* On syncer work-list */
102#define	BO_WWAIT	(1 << 1)	/* Wait for output to complete */
103
104#define	BO_LOCK(bo) \
105	do { \
106		KASSERT (bo->bo_mtx != NULL, ("No lock in bufobj")); \
107		mtx_lock((bo)->bo_mtx); \
108	} while (0)
109
110#define BO_UNLOCK(bo) \
111	do { \
112		KASSERT (bo->bo_mtx != NULL, ("No lock in bufobj")); \
113		mtx_unlock((bo)->bo_mtx); \
114	} while (0)
115
116#define	BO_MTX(bo)		((bo)->bo_mtx)
117#define	ASSERT_BO_LOCKED(bo)	mtx_assert(bo->bo_mtx, MA_OWNED)
118#define	ASSERT_BO_UNLOCKED(bo)	mtx_assert(bo->bo_mtx, MA_NOTOWNED)
119
120void bufobj_wdrop(struct bufobj *bo);
121void bufobj_wref(struct bufobj *bo);
122int bufobj_wwait(struct bufobj *bo, int slpflag, int timeo);
123
124#endif /* defined(_KERNEL) || defined(_KVM_VNODE) */
125#endif /* _SYS_BUFOBJ_H_ */
126