bufobj.h revision 331158 
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 * $FreeBSD: stable/11/sys/sys/bufobj.h 331158 2018-03-19 03:04:19Z eadler $
29 */
30
31/*
32 * Architectural notes:
33 *
34 * bufobj is a new object which is what buffers hang from in the buffer
35 * cache.
36 *
37 * This used to be vnodes, but we need non-vnode code to be able
38 * to use the buffer cache as well, specifically geom classes like gbde,
39 * raid3 and raid5.
40 *
41 * All vnodes will contain a bufobj initially, but down the road we may
42 * want to only allocate bufobjs when they are needed.  There could be a
43 * large number of vnodes in the system which wouldn't need a bufobj during
44 * their lifetime.
45 *
46 * The exact relationship to the vmobject is not determined at this point,
47 * it may in fact be that we find them to be two sides of the same object
48 * once things starts to crystalize.
49 */
50
51#ifndef _SYS_BUFOBJ_H_
52#define _SYS_BUFOBJ_H_
53
54#if defined(_KERNEL) || defined(_KVM_VNODE)
55
56#include <sys/queue.h>
57#include <sys/_lock.h>
58#include <sys/_rwlock.h>
59#include <sys/_pctrie.h>
60
61struct bufobj;
62struct buf_ops;
63
64extern struct buf_ops buf_ops_bio;
65
66TAILQ_HEAD(buflists, buf);
67
68/* A Buffer list & trie */
69struct bufv {
70	struct buflists	bv_hd;		/* Sorted blocklist */
71	struct pctrie	bv_root;	/* Buf trie */
72	int		bv_cnt;		/* Number of buffers */
73};
74
75typedef void b_strategy_t(struct bufobj *, struct buf *);
76typedef int b_write_t(struct buf *);
77typedef int b_sync_t(struct bufobj *, int waitfor);
78typedef void b_bdflush_t(struct bufobj *, struct buf *);
79
80struct buf_ops {
81	char		*bop_name;
82	b_write_t	*bop_write;
83	b_strategy_t	*bop_strategy;
84	b_sync_t	*bop_sync;
85	b_bdflush_t	*bop_bdflush;
86};
87
88#define BO_STRATEGY(bo, bp)	((bo)->bo_ops->bop_strategy((bo), (bp)))
89#define BO_SYNC(bo, w)		((bo)->bo_ops->bop_sync((bo), (w)))
90#define BO_WRITE(bo, bp)	((bo)->bo_ops->bop_write((bp)))
91#define BO_BDFLUSH(bo, bp)	((bo)->bo_ops->bop_bdflush((bo), (bp)))
92
93/*
94 * Locking notes:
95 * 'S' is sync_mtx
96 * 'v' is the vnode lock which embeds the bufobj.
97 * '-' Constant and unchanging after initialization.
98 */
99struct bufobj {
100	struct rwlock	bo_lock;	/* Lock which protects "i" things */
101	struct buf_ops	*bo_ops;	/* - Buffer operations */
102	struct vm_object *bo_object;	/* v Place to store VM object */
103	LIST_ENTRY(bufobj) bo_synclist;	/* S dirty vnode list */
104	void		*bo_private;	/* private pointer */
105	struct vnode	*__bo_vnode;	/*
106					 * XXX: This vnode pointer is here
107					 * XXX: only to keep the syncer working
108					 * XXX: for now.
109					 */
110	struct bufv	bo_clean;	/* i Clean buffers */
111	struct bufv	bo_dirty;	/* i Dirty buffers */
112	long		bo_numoutput;	/* i Writes in progress */
113	u_int		bo_flag;	/* i Flags */
114	int		bo_bsize;	/* - Block size for i/o */
115};
116
117/*
118 * XXX BO_ONWORKLST could be replaced with a check for NULL list elements
119 * in v_synclist.
120 */
121#define	BO_ONWORKLST	(1 << 0)	/* On syncer work-list */
122#define	BO_WWAIT	(1 << 1)	/* Wait for output to complete */
123#define	BO_DEAD		(1 << 2)	/* Dead; only with INVARIANTS */
124
125#define	BO_LOCKPTR(bo)		(&(bo)->bo_lock)
126#define	BO_LOCK(bo)		rw_wlock(BO_LOCKPTR((bo)))
127#define	BO_UNLOCK(bo)		rw_wunlock(BO_LOCKPTR((bo)))
128#define	BO_RLOCK(bo)		rw_rlock(BO_LOCKPTR((bo)))
129#define	BO_RUNLOCK(bo)		rw_runlock(BO_LOCKPTR((bo)))
130#define	ASSERT_BO_WLOCKED(bo)	rw_assert(BO_LOCKPTR((bo)), RA_WLOCKED)
131#define	ASSERT_BO_LOCKED(bo)	rw_assert(BO_LOCKPTR((bo)), RA_LOCKED)
132#define	ASSERT_BO_UNLOCKED(bo)	rw_assert(BO_LOCKPTR((bo)), RA_UNLOCKED)
133
134void bufobj_wdrop(struct bufobj *bo);
135void bufobj_wref(struct bufobj *bo);
136void bufobj_wrefl(struct bufobj *bo);
137int bufobj_invalbuf(struct bufobj *bo, int flags, int slpflag, int slptimeo);
138int bufobj_wwait(struct bufobj *bo, int slpflag, int timeo);
139int bufsync(struct bufobj *bo, int waitfor);
140void bufbdflush(struct bufobj *bo, struct buf *bp);
141
142#endif /* defined(_KERNEL) || defined(_KVM_VNODE) */
143#endif /* _SYS_BUFOBJ_H_ */
144