1 /*- 2 * SPDX-License-Identifier: BSD-2-Clause 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 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 #include <sys/_lock.h> 56 #include <sys/_rwlock.h> 57 #include <sys/_pctrie.h> 58 59 struct bufobj; 60 struct buf_ops; 61 62 extern struct buf_ops buf_ops_bio; 63 64 TAILQ_HEAD(buflists, buf); 65 66 /* A Buffer list & trie */ 67 struct bufv { 68 struct buflists bv_hd; /* Sorted blocklist */ 69 struct pctrie bv_root; /* Buf trie */ 70 int bv_cnt; /* Number of buffers */ 71 }; 72 73 typedef void b_strategy_t(struct bufobj *, struct buf *); 74 typedef int b_write_t(struct buf *); 75 typedef int b_sync_t(struct bufobj *, int waitfor); 76 typedef void b_bdflush_t(struct bufobj *, struct buf *); 77 78 struct buf_ops { 79 const char *bop_name; 80 b_write_t *bop_write; 81 b_strategy_t *bop_strategy; 82 b_sync_t *bop_sync; 83 b_bdflush_t *bop_bdflush; 84 }; 85 86 #define BO_STRATEGY(bo, bp) ((bo)->bo_ops->bop_strategy((bo), (bp))) 87 #define BO_SYNC(bo, w) ((bo)->bo_ops->bop_sync((bo), (w))) 88 #define BO_WRITE(bo, bp) ((bo)->bo_ops->bop_write((bp))) 89 #define BO_BDFLUSH(bo, bp) ((bo)->bo_ops->bop_bdflush((bo), (bp))) 90 91 /* 92 * Locking notes: 93 * 'S' is sync_mtx 94 * 'v' is the vnode lock which embeds the bufobj. 95 * '-' Constant and unchanging after initialization. 96 */ 97 struct bufobj { 98 struct rwlock bo_lock; /* Lock which protects "i" things */ 99 struct buf_ops *bo_ops; /* - Buffer operations */ 100 struct vm_object *bo_object; /* v Place to store VM object */ 101 LIST_ENTRY(bufobj) bo_synclist; /* S dirty vnode list */ 102 void *bo_private; /* private pointer */ 103 struct bufv bo_clean; /* i Clean buffers */ 104 struct bufv bo_dirty; /* i Dirty buffers */ 105 int bo_numoutput; /* i Writes in progress */ 106 u_int bo_flag; /* i Flags */ 107 int bo_domain; /* - Clean queue affinity */ 108 int bo_bsize; /* - Block size for i/o */ 109 }; 110 111 /* 112 * XXX BO_ONWORKLST could be replaced with a check for NULL list elements 113 * in v_synclist. 114 */ 115 #define BO_ONWORKLST (1 << 0) /* On syncer work-list */ 116 #define BO_WWAIT (1 << 1) /* Wait for output to complete */ 117 #define BO_DEAD (1 << 2) /* Dead; only with INVARIANTS */ 118 #define BO_NOBUFS (1 << 3) /* No bufs allowed */ 119 120 #define BO_LOCKPTR(bo) (&(bo)->bo_lock) 121 #define BO_LOCK(bo) rw_wlock(BO_LOCKPTR((bo))) 122 #define BO_UNLOCK(bo) rw_wunlock(BO_LOCKPTR((bo))) 123 #define BO_RLOCK(bo) rw_rlock(BO_LOCKPTR((bo))) 124 #define BO_RUNLOCK(bo) rw_runlock(BO_LOCKPTR((bo))) 125 #define ASSERT_BO_WLOCKED(bo) rw_assert(BO_LOCKPTR((bo)), RA_WLOCKED) 126 #define ASSERT_BO_LOCKED(bo) rw_assert(BO_LOCKPTR((bo)), RA_LOCKED) 127 #define ASSERT_BO_UNLOCKED(bo) rw_assert(BO_LOCKPTR((bo)), RA_UNLOCKED) 128 129 void bufobj_init(struct bufobj *bo, void *priv); 130 void bufobj_wdrop(struct bufobj *bo); 131 void bufobj_wref(struct bufobj *bo); 132 void bufobj_wrefl(struct bufobj *bo); 133 int bufobj_invalbuf(struct bufobj *bo, int flags, int slpflag, int slptimeo); 134 int bufobj_wwait(struct bufobj *bo, int slpflag, int timeo); 135 int bufsync(struct bufobj *bo, int waitfor); 136 void bufbdflush(struct bufobj *bo, struct buf *bp); 137 138 #endif /* defined(_KERNEL) || defined(_KVM_VNODE) */ 139 #endif /* _SYS_BUFOBJ_H_ */ 140