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 #ifndef _VM_VM_PAGE_H_
  67 #include <vm/vm_page.h>
  68 #endif
  69
  70 /*
  71  * Initialize a lock.
  72  */
  73 #define BUF_LOCKINIT(bp) \
  74         lockinit(&(bp)->b_lock, buf_wmesg, 0, 0)
  75
  76 /*
  77  *
  78  * Get a lock sleeping non-interruptably until it becomes available.
  79  *
  80  * XXX lk_wmesg can race, but should not result in any operational issues.
  81  */
  82 static __inline int
  83 BUF_LOCK(struct buf *bp, int locktype)
  84 {
  85         bp->b_lock.lk_wmesg = buf_wmesg;
  86         return (lockmgr(&(bp)->b_lock, locktype));
  87 }
  88 /*
  89  * Get a lock sleeping with specified interruptably and timeout.
  90  *
  91  * XXX lk_timo can race against other entities calling BUF_TIMELOCK,
  92  * but will not interfere with entities calling BUF_LOCK since LK_TIMELOCK
  93  * will not be set in that case.
  94  *
  95  * XXX lk_wmesg can race, but should not result in any operational issues.
  96  */
  97 static __inline int
  98 BUF_TIMELOCK(struct buf *bp, int locktype, char *wmesg, int timo)
  99 {
 100         bp->b_lock.lk_wmesg = wmesg;
 101         bp->b_lock.lk_timo = timo;
 102         return (lockmgr(&(bp)->b_lock, locktype | LK_TIMELOCK));
 103 }
 104 /*
 105  * Release a lock. Only the acquiring process may free the lock unless
 106  * it has been handed off to biodone.
 107  */
 108 static __inline void
 109 BUF_UNLOCK(struct buf *bp)
 110 {
 111         lockmgr(&(bp)->b_lock, LK_RELEASE);
 112 }
 113
 114 /*
 115  * When initiating asynchronous I/O, change ownership of the lock to the
 116  * kernel. Once done, the lock may legally released by biodone. The
 117  * original owning process can no longer acquire it recursively, but must
 118  * wait until the I/O is completed and the lock has been freed by biodone.
 119  */
 120 static __inline void
 121 BUF_KERNPROC(struct buf *bp)
 122 {
 123         lockmgr_kernproc(&(bp)->b_lock);
 124 }
 125 /*
 126  * Find out the number of references to a lock.
 127  *
 128  * The non-blocking version should only be used for assertions in cases
 129  * where the buffer is expected to be owned or otherwise data stable.
 130  */
 131 static __inline int
 132 BUF_REFCNT(struct buf *bp)
 133 {
 134         return (lockcount(&(bp)->b_lock));
 135 }
 136
 137 static __inline int
 138 BUF_REFCNTNB(struct buf *bp)
 139 {
 140         return (lockcountnb(&(bp)->b_lock));
 141 }
 142
 143 /*
 144  * Free a buffer lock.
 145  */
 146 #define BUF_LOCKFREE(bp)                        \
 147         if (BUF_REFCNTNB(bp) > 0)               \
 148                 panic("free locked buf")
 149
 150 static __inline void
 151 bioq_init(struct bio_queue_head *bioq)
 152 {
 153         TAILQ_INIT(&bioq->queue);
 154         bioq->off_unused = 0;
 155         bioq->reorder = 0;
 156         bioq->transition = NULL;
 157         bioq->bio_unused = NULL;
 158 }
 159
 160 static __inline void
 161 bioq_insert_tail(struct bio_queue_head *bioq, struct bio *bio)
 162 {
 163         bioq->transition = NULL;
 164         TAILQ_INSERT_TAIL(&bioq->queue, bio, bio_act);
 165 }
 166
 167 static __inline void
 168 bioq_remove(struct bio_queue_head *bioq, struct bio *bio)
 169 {
 170         /*
 171          * Adjust read insertion point when removing the bioq.  The
 172          * bio after the insert point is a write so move backwards
 173          * one (NULL will indicate all the reads have cleared).
 174          */
 175         if (bio == bioq->transition)
 176                 bioq->transition = TAILQ_NEXT(bio, bio_act);
 177         TAILQ_REMOVE(&bioq->queue, bio, bio_act);
 178 }
 179
 180 static __inline struct bio *
 181 bioq_first(struct bio_queue_head *bioq)
 182 {
 183         return (TAILQ_FIRST(&bioq->queue));
 184 }
 185
 186 /*
 187  * Adjust buffer cache buffer's activity count.  This
 188  * works similarly to vm_page->act_count.
 189  */
 190 static __inline void
 191 buf_act_advance(struct buf *bp)
 192 {
 193         if (bp->b_act_count > ACT_MAX - ACT_ADVANCE)
 194                 bp->b_act_count = ACT_MAX;
 195         else
 196                 bp->b_act_count += ACT_ADVANCE;
 197 }
 198
 199 static __inline void
 200 buf_act_decline(struct buf *bp)
 201 {
 202         if (bp->b_act_count < ACT_DECLINE)
 203                 bp->b_act_count = 0;
 204         else
 205                 bp->b_act_count -= ACT_DECLINE;
 206 }
 207
 208 /*
 209  * biodeps inlines - used by softupdates and HAMMER.
 210  */
 211 static __inline void
 212 buf_dep_init(struct buf *bp)
 213 {
 214         bp->b_ops = NULL;
 215         LIST_INIT(&bp->b_dep);
 216 }
 217
 218 /*
 219  * Precondition: the buffer has some dependencies.
 220  */
 221 static __inline void
 222 buf_deallocate(struct buf *bp)
 223 {
 224         struct bio_ops *ops = bp->b_ops;
 225
 226         KKASSERT(! LIST_EMPTY(&bp->b_dep));
 227         if (ops)
 228                 ops->io_deallocate(bp);
 229 }
 230
 231 static __inline int
 232 buf_countdeps(struct buf *bp, int n)
 233 {
 234         struct bio_ops *ops = bp->b_ops;
 235         int r;
 236
 237         if (ops)
 238                 r = ops->io_countdeps(bp, n);
 239         else
 240                 r = 0;
 241         return(r);
 242 }
 243
 244 static __inline void
 245 buf_start(struct buf *bp)
 246 {
 247         struct bio_ops *ops = bp->b_ops;
 248
 249         if (ops)
 250                 ops->io_start(bp);
 251 }
 252
 253 static __inline void
 254 buf_complete(struct buf *bp)
 255 {
 256         struct bio_ops *ops = bp->b_ops;
 257
 258         if (ops)
 259                 ops->io_complete(bp);
 260 }
 261
 262 static __inline int
 263 buf_fsync(struct vnode *vp)
 264 {
 265         struct bio_ops *ops = vp->v_mount->mnt_bioops;
 266         int r;
 267
 268         if (ops)
 269                 r = ops->io_fsync(vp);
 270         else
 271                 r = 0;
 272         return(r);
 273 }
 274
 275 static __inline void
 276 buf_movedeps(struct buf *bp1, struct buf *bp2)
 277 {
 278         struct bio_ops *ops = bp1->b_ops;
 279
 280         if (ops)
 281                 ops->io_movedeps(bp1, bp2);
 282 }
 283
 284 static __inline int
 285 buf_checkread(struct buf *bp)
 286 {
 287         struct bio_ops *ops = bp->b_ops;
 288
 289         if (ops)
 290                 return(ops->io_checkread(bp));
 291         return(0);
 292 }
 293
 294 static __inline int
 295 buf_checkwrite(struct buf *bp)
 296 {
 297         struct bio_ops *ops = bp->b_ops;
 298
 299         if (ops)
 300                 return(ops->io_checkwrite(bp));
 301         return(0);
 302 }
 303
 304 /*
 305  * Chained biodone.  The bio callback was made and the callback function
 306  * wishes to chain the biodone.  If no BIO's are left we call bpdone()
 307  * with elseit=TRUE (asynchronous completion).
 308  */
 309 static __inline void
 310 biodone_chain(struct bio *bio)
 311 {
 312         if (bio->bio_prev)
 313                 biodone(bio->bio_prev);
 314         else
 315                 bpdone(bio->bio_buf, 1);
 316 }
 317
 318 #endif /* _KERNEL */
 319
 320 #endif /* !_SYS_BUF2_H_ */