sys/sys/buf2.h

   1 /*
   2  * Copyright (c) 1982, 1986, 1989, 1993
   3  *      The Regents of the University of California.  All rights reserved.
   4  * (c) UNIX System Laboratories, Inc.
   5  * All or some portions of this file are derived from material licensed
   6  * to the University of California by American Telephone and Telegraph
   7  * Co. or Unix System Laboratories, Inc. and are reproduced herein with
   8  * the permission of UNIX System Laboratories, Inc.
   9  *
  10  * Redistribution and use in source and binary forms, with or without
  11  * modification, are permitted provided that the following conditions
  12  * are met:
  13  * 1. Redistributions of source code must retain the above copyright
  14  *    notice, this list of conditions and the following disclaimer.
  15  * 2. Redistributions in binary form must reproduce the above copyright
  16  *    notice, this list of conditions and the following disclaimer in the
  17  *    documentation and/or other materials provided with the distribution.
  18  * 3. All advertising materials mentioning features or use of this software
  19  *    must display the following acknowledgement:
  20  *      This product includes software developed by the University of
  21  *      California, Berkeley and its contributors.
  22  * 4. Neither the name of the University nor the names of its contributors
  23  *    may be used to endorse or promote products derived from this software
  24  *    without specific prior written permission.
  25  *
  26  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  27  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  28  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  29  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  30  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  31  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  32  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  33  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  34  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  35  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  36  * SUCH DAMAGE.
  37  *
  38  *      @(#)buf.h       8.9 (Berkeley) 3/30/95
  39  * $FreeBSD: src/sys/sys/buf.h,v 1.88.2.10 2003/01/25 19:02:23 dillon Exp $
  40  * $DragonFly: src/sys/sys/buf2.h,v 1.21 2008/01/28 07:19:06 nth Exp $
  41  */
  42
  43 #ifndef _SYS_BUF2_H_
  44 #define _SYS_BUF2_H_
  45
  46 #ifdef _KERNEL
  47
  48 #ifndef _SYS_BUF_H_
  49 #include <sys/buf.h>            /* crit_*() functions */
  50 #endif
  51 #ifndef _SYS_GLOBALDATA_H_
  52 #include <sys/globaldata.h>     /* curthread */
  53 #endif
  54 #ifndef _SYS_THREAD2_H_
  55 #include <sys/thread2.h>        /* crit_*() functions */
  56 #endif
  57 #ifndef _SYS_SPINLOCK2_H_
  58 #include <sys/spinlock2.h>      /* crit_*() functions */
  59 #endif
  60 #ifndef _SYS_MOUNT_H_
  61 #include <sys/mount.h>
  62 #endif
  63 #ifndef _SYS_VNODE_H_
  64 #include <sys/vnode.h>
  65 #endif
  66
  67 /*
  68  * Initialize a lock.
  69  */
  70 #define BUF_LOCKINIT(bp) \
  71         lockinit(&(bp)->b_lock, buf_wmesg, 0, 0)
  72
  73 /*
  74  *
  75  * Get a lock sleeping non-interruptably until it becomes available.
  76  *
  77  * XXX lk_wmesg can race, but should not result in any operational issues.
  78  */
  79 static __inline int
  80 BUF_LOCK(struct buf *bp, int locktype)
  81 {
  82         bp->b_lock.lk_wmesg = buf_wmesg;
  83         return (lockmgr(&(bp)->b_lock, locktype));
  84 }
  85 /*
  86  * Get a lock sleeping with specified interruptably and timeout.
  87  *
  88  * XXX lk_timo can race against other entities calling BUF_TIMELOCK,
  89  * but will not interfere with entities calling BUF_LOCK since LK_TIMELOCK
  90  * will not be set in that case.
  91  *
  92  * XXX lk_wmesg can race, but should not result in any operational issues.
  93  */
  94 static __inline int
  95 BUF_TIMELOCK(struct buf *bp, int locktype, char *wmesg, int timo)
  96 {
  97         bp->b_lock.lk_wmesg = wmesg;
  98         bp->b_lock.lk_timo = timo;
  99         return (lockmgr(&(bp)->b_lock, locktype | LK_TIMELOCK));
 100 }
 101 /*
 102  * Release a lock. Only the acquiring process may free the lock unless
 103  * it has been handed off to biodone.
 104  */
 105 static __inline void
 106 BUF_UNLOCK(struct buf *bp)
 107 {
 108         lockmgr(&(bp)->b_lock, LK_RELEASE);
 109 }
 110
 111 /*
 112  * When initiating asynchronous I/O, change ownership of the lock to the
 113  * kernel. Once done, the lock may legally released by biodone. The
 114  * original owning process can no longer acquire it recursively, but must
 115  * wait until the I/O is completed and the lock has been freed by biodone.
 116  */
 117 static __inline void
 118 BUF_KERNPROC(struct buf *bp)
 119 {
 120         lockmgr_kernproc(&(bp)->b_lock);
 121 }
 122 /*
 123  * Find out the number of references to a lock.
 124  *
 125  * The non-blocking version should only be used for assertions in cases
 126  * where the buffer is expected to be owned or otherwise data stable.
 127  */
 128 static __inline int
 129 BUF_REFCNT(struct buf *bp)
 130 {
 131         return (lockcount(&(bp)->b_lock));
 132 }
 133
 134 static __inline int
 135 BUF_REFCNTNB(struct buf *bp)
 136 {
 137         return (lockcountnb(&(bp)->b_lock));
 138 }
 139
 140 /*
 141  * Free a buffer lock.
 142  */
 143 #define BUF_LOCKFREE(bp)                        \
 144         if (BUF_REFCNTNB(bp) > 0)               \
 145                 panic("free locked buf")
 146
 147 static __inline void
 148 bioq_init(struct bio_queue_head *head)
 149 {
 150         TAILQ_INIT(&head->queue);
 151         head->last_offset = 0;
 152         head->insert_point = NULL;
 153         head->switch_point = NULL;
 154 }
 155
 156 static __inline void
 157 bioq_insert_tail(struct bio_queue_head *head, struct bio *bio)
 158 {
 159         if ((bio->bio_buf->b_flags & B_ORDERED) != 0) {
 160                 head->insert_point = bio;
 161                 head->switch_point = NULL;
 162         }
 163         TAILQ_INSERT_TAIL(&head->queue, bio, bio_act);
 164 }
 165
 166 static __inline void
 167 bioq_remove(struct bio_queue_head *head, struct bio *bio)
 168 {
 169         if (bio == head->switch_point)
 170                 head->switch_point = TAILQ_NEXT(bio, bio_act);
 171         if (bio == head->insert_point) {
 172                 head->insert_point = TAILQ_PREV(bio, bio_queue, bio_act);
 173                 if (head->insert_point == NULL)
 174                         head->last_offset = 0;
 175         } else if (bio == TAILQ_FIRST(&head->queue))
 176                 head->last_offset = bio->bio_offset;
 177         TAILQ_REMOVE(&head->queue, bio, bio_act);
 178         if (TAILQ_FIRST(&head->queue) == head->switch_point)
 179                 head->switch_point = NULL;
 180 }
 181
 182 static __inline struct bio *
 183 bioq_first(struct bio_queue_head *head)
 184 {
 185         return (TAILQ_FIRST(&head->queue));
 186 }
 187
 188 /*
 189  * biodeps inlines - used by softupdates and HAMMER.
 190  */
 191 static __inline void
 192 buf_dep_init(struct buf *bp)
 193 {
 194         bp->b_ops = NULL;
 195         LIST_INIT(&bp->b_dep);
 196 }
 197
 198 /*
 199  * Precondition: the buffer has some dependencies.
 200  */
 201 static __inline void
 202 buf_deallocate(struct buf *bp)
 203 {
 204         struct bio_ops *ops = bp->b_ops;
 205
 206         KKASSERT(! LIST_EMPTY(&bp->b_dep));
 207         if (ops)
 208                 ops->io_deallocate(bp);
 209 }
 210
 211 static __inline int
 212 buf_countdeps(struct buf *bp, int n)
 213 {
 214         struct bio_ops *ops = bp->b_ops;
 215         int r;
 216
 217         if (ops)
 218                 r = ops->io_countdeps(bp, n);
 219         else
 220                 r = 0;
 221         return(r);
 222 }
 223
 224 static __inline void
 225 buf_start(struct buf *bp)
 226 {
 227         struct bio_ops *ops = bp->b_ops;
 228
 229         if (ops)
 230                 ops->io_start(bp);
 231 }
 232
 233 static __inline void
 234 buf_complete(struct buf *bp)
 235 {
 236         struct bio_ops *ops = bp->b_ops;
 237
 238         if (ops)
 239                 ops->io_complete(bp);
 240 }
 241
 242 static __inline int
 243 buf_fsync(struct vnode *vp)
 244 {
 245         struct bio_ops *ops = vp->v_mount->mnt_bioops;
 246         int r;
 247
 248         if (ops)
 249                 r = ops->io_fsync(vp);
 250         else
 251                 r = 0;
 252         return(r);
 253 }
 254
 255 static __inline void
 256 buf_movedeps(struct buf *bp1, struct buf *bp2)
 257 {
 258         struct bio_ops *ops = bp1->b_ops;
 259
 260         if (ops)
 261                 ops->io_movedeps(bp1, bp2);
 262 }
 263
 264 static __inline int
 265 buf_checkread(struct buf *bp)
 266 {
 267         struct bio_ops *ops = bp->b_ops;
 268
 269         if (ops)
 270                 return(ops->io_checkread(bp));
 271         return(0);
 272 }
 273
 274 static __inline int
 275 buf_checkwrite(struct buf *bp)
 276 {
 277         struct bio_ops *ops = bp->b_ops;
 278
 279         if (ops)
 280                 return(ops->io_checkwrite(bp));
 281         return(0);
 282 }
 283
 284 #endif /* _KERNEL */
 285
 286 #endif /* !_SYS_BUF2_H_ */