FreeBSD/Linux Kernel Cross Reference
sys/sys/bufobj.h
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: releng/6.4/sys/sys/bufobj.h 170553 2007-06-11 10:53:48Z kib $
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
56 struct bufobj;
57 struct buf_ops;
58
59 extern struct buf_ops buf_ops_bio;
60
61 TAILQ_HEAD(buflists, buf);
62
63 /* A Buffer splay list */
64 struct 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
70 typedef void b_strategy_t(struct bufobj *, struct buf *);
71 typedef int b_write_t(struct buf *);
72 typedef int b_sync_t(struct bufobj *, int waitfor, struct thread *td);
73 typedef void b_bdflush_t(struct bufobj *, struct buf *);
74
75 struct buf_ops {
76 char *bop_name;
77 b_write_t *bop_write;
78 b_strategy_t *bop_strategy;
79 b_sync_t *bop_sync;
80 b_bdflush_t *bop_bdflush;
81 };
82
83 #define BO_STRATEGY(bo, bp) ((bo)->bo_ops->bop_strategy((bo), (bp)))
84 #define BO_SYNC(bo, w, td) ((bo)->bo_ops->bop_sync((bo), (w), (td)))
85 #define BO_WRITE(bo, bp) ((bo)->bo_ops->bop_write((bp)))
86 #define BO_BDFLUSH(bo, bp) ((bo)->bo_ops->bop_bdflush((bo), (bp)))
87
88 struct bufobj {
89 struct mtx *bo_mtx; /* Mutex which protects "i" things */
90 struct bufv bo_clean; /* i Clean buffers */
91 struct bufv bo_dirty; /* i Dirty buffers */
92 long bo_numoutput; /* i Writes in progress */
93 u_int bo_flag; /* i Flags */
94 struct buf_ops *bo_ops; /* - Buffer operations */
95 int bo_bsize; /* - Block size for i/o */
96 struct vm_object *bo_object; /* v Place to store VM object */
97 LIST_ENTRY(bufobj) bo_synclist; /* S dirty vnode list */
98 void *bo_private; /* private pointer */
99 struct vnode *__bo_vnode; /*
100 * XXX: This vnode pointer is here
101 * XXX: only to keep the syncer working
102 * XXX: for now.
103 */
104 };
105
106 /*
107 * XXX BO_ONWORKLST could be replaced with a check for NULL list elements
108 * in v_synclist.
109 */
110 #define BO_ONWORKLST (1 << 0) /* On syncer work-list */
111 #define BO_WWAIT (1 << 1) /* Wait for output to complete */
112
113 #define BO_LOCK(bo) \
114 do { \
115 KASSERT((bo)->bo_mtx != NULL, ("No lock in bufobj")); \
116 mtx_lock((bo)->bo_mtx); \
117 } while (0)
118
119 #define BO_UNLOCK(bo) \
120 do { \
121 KASSERT((bo)->bo_mtx != NULL, ("No lock in bufobj")); \
122 mtx_unlock((bo)->bo_mtx); \
123 } while (0)
124
125 #define BO_MTX(bo) ((bo)->bo_mtx)
126 #define ASSERT_BO_LOCKED(bo) mtx_assert(bo->bo_mtx, MA_OWNED)
127 #define ASSERT_BO_UNLOCKED(bo) mtx_assert(bo->bo_mtx, MA_NOTOWNED)
128
129 void bufobj_wdrop(struct bufobj *bo);
130 void bufobj_wref(struct bufobj *bo);
131 void bufobj_wrefl(struct bufobj *bo);
132 int bufobj_invalbuf(struct bufobj *bo, int flags, struct thread *td, int slpflag, int slptimeo);
133 int bufobj_wwait(struct bufobj *bo, int slpflag, int timeo);
134 int bufsync(struct bufobj *bo, int waitfor, struct thread *td);
135 void bufbdflush(struct bufobj *bo, struct buf *bp);
136
137 #endif /* defined(_KERNEL) || defined(_KVM_VNODE) */
138 #endif /* _SYS_BUFOBJ_H_ */
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