bufobj.h revision 176708 
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 176708 2008-03-01 19:47:50Z attilio $
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 be 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;
58struct thread;
59
60extern struct buf_ops buf_ops_bio;
61
62TAILQ_HEAD(buflists, buf);
63
64/* A Buffer splay list */
65struct bufv {
66	struct buflists	bv_hd;		/* Sorted blocklist */
67	struct buf	*bv_root;	/* Buf splay tree */
68	int		bv_cnt;		/* Number of buffers */
69};
70
71typedef void b_strategy_t(struct bufobj *, struct buf *);
72typedef int b_write_t(struct buf *);
73typedef int b_sync_t(struct bufobj *, int waitfor, struct thread *td);
74typedef void b_bdflush_t(struct bufobj *, struct buf *);
75
76struct buf_ops {
77	char		*bop_name;
78	b_write_t	*bop_write;
79	b_strategy_t	*bop_strategy;
80	b_sync_t	*bop_sync;
81	b_bdflush_t	*bop_bdflush;
82};
83
84#define BO_STRATEGY(bo, bp)	((bo)->bo_ops->bop_strategy((bo), (bp)))
85#define BO_SYNC(bo, w, td)	((bo)->bo_ops->bop_sync((bo), (w), (td)))
86#define BO_WRITE(bo, bp)	((bo)->bo_ops->bop_write((bp)))
87#define BO_BDFLUSH(bo, bp)	((bo)->bo_ops->bop_bdflush((bo), (bp)))
88
89struct bufobj {
90	struct mtx	*bo_mtx;	/* Mutex which protects "i" things */
91	struct bufv	bo_clean;	/* i Clean buffers */
92	struct bufv	bo_dirty;	/* i Dirty buffers */
93	long		bo_numoutput;	/* i Writes in progress */
94	u_int		bo_flag;	/* i Flags */
95	struct buf_ops	*bo_ops;	/* - Buffer operations */
96	int		bo_bsize;	/* - Block size for i/o */
97	struct vm_object *bo_object;	/* v Place to store VM object */
98	LIST_ENTRY(bufobj) bo_synclist;	/* S dirty vnode list */
99	void		*bo_private;	/* private pointer */
100	struct vnode	*__bo_vnode;	/*
101					 * XXX: This vnode pointer is here
102					 * XXX: only to keep the syncer working
103					 * XXX: for now.
104					 */
105};
106
107/*
108 * XXX BO_ONWORKLST could be replaced with a check for NULL list elements
109 * in v_synclist.
110 */
111#define	BO_ONWORKLST	(1 << 0)	/* On syncer work-list */
112#define	BO_WWAIT	(1 << 1)	/* Wait for output to complete */
113#define	BO_NEEDSGIANT	(1 << 2)	/* Require giant for child buffers. */
114
115#define	BO_LOCK(bo) \
116	do { \
117		KASSERT((bo)->bo_mtx != NULL, ("No lock in bufobj")); \
118		mtx_lock((bo)->bo_mtx); \
119	} while (0)
120
121#define BO_UNLOCK(bo) \
122	do { \
123		KASSERT((bo)->bo_mtx != NULL, ("No lock in bufobj")); \
124		mtx_unlock((bo)->bo_mtx); \
125	} while (0)
126
127#define	BO_MTX(bo)		((bo)->bo_mtx)
128#define	ASSERT_BO_LOCKED(bo)	mtx_assert(bo->bo_mtx, MA_OWNED)
129#define	ASSERT_BO_UNLOCKED(bo)	mtx_assert(bo->bo_mtx, MA_NOTOWNED)
130
131void bufobj_wdrop(struct bufobj *bo);
132void bufobj_wref(struct bufobj *bo);
133void bufobj_wrefl(struct bufobj *bo);
134int bufobj_invalbuf(struct bufobj *bo, int flags, struct thread *td, int slpflag, int slptimeo);
135int bufobj_wwait(struct bufobj *bo, int slpflag, int timeo);
136int bufsync(struct bufobj *bo, int waitfor, struct thread *td);
137void bufbdflush(struct bufobj *bo, struct buf *bp);
138
139#endif /* defined(_KERNEL) || defined(_KVM_VNODE) */
140#endif /* _SYS_BUFOBJ_H_ */
141