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. Neither the name of the University nor the names of its contributors
  19  *    may be used to endorse or promote products derived from this software
  20  *    without specific prior written permission.
  21  *
  22  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  23  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  24  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  25  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  26  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  27  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  28  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  29  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  30  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  31  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  32  * SUCH DAMAGE.
  33  *
  34  *      @(#)buf.h       8.9 (Berkeley) 3/30/95
  35  * $FreeBSD: src/sys/sys/buf.h,v 1.88.2.10 2003/01/25 19:02:23 dillon Exp $
  36  * $DragonFly: src/sys/sys/buf2.h,v 1.21 2008/01/28 07:19:06 nth Exp $
  37  */
  38
  39 #ifndef _SYS_BUF2_H_
  40 #define _SYS_BUF2_H_
  41
  42 #ifdef _KERNEL
  43
  44 #ifndef _SYS_BUF_H_
  45 #include <sys/buf.h>            /* crit_*() functions */
  46 #endif
  47 #ifndef _SYS_GLOBALDATA_H_
  48 #include <sys/globaldata.h>     /* curthread */
  49 #endif
  50 #ifndef _SYS_THREAD2_H_
  51 #include <sys/thread2.h>        /* crit_*() functions */
  52 #endif
  53 #ifndef _SYS_SPINLOCK2_H_
  54 #include <sys/spinlock2.h>      /* crit_*() functions */
  55 #endif
  56 #ifndef _SYS_MOUNT_H_
  57 #include <sys/mount.h>
  58 #endif
  59 #ifndef _SYS_VNODE_H_
  60 #include <sys/vnode.h>
  61 #endif
  62 #ifndef _VM_VM_PAGE_H_
  63 #include <vm/vm_page.h>
  64 #endif
  65
  66 /*
  67  * Initialize a lock.
  68  */
  69 #define BUF_LOCKINIT(bp) \
  70         lockinit(&(bp)->b_lock, buf_wmesg, 0, 0)
  71
  72 /*
  73  *
  74  * Get a lock sleeping non-interruptably until it becomes available.
  75  *
  76  * XXX lk_wmesg can race, but should not result in any operational issues.
  77  */
  78 static __inline int
  79 BUF_LOCK(struct buf *bp, int locktype)
  80 {
  81         bp->b_lock.lk_wmesg = buf_wmesg;
  82         return (lockmgr(&(bp)->b_lock, locktype));
  83 }
  84 /*
  85  * Get a lock sleeping with specified interruptably and timeout.
  86  *
  87  * XXX lk_timo can race against other entities calling BUF_TIMELOCK,
  88  * but will not interfere with entities calling BUF_LOCK since LK_TIMELOCK
  89  * will not be set in that case.
  90  *
  91  * XXX lk_wmesg can race, but should not result in any operational issues.
  92  */
  93 static __inline int
  94 BUF_TIMELOCK(struct buf *bp, int locktype, char *wmesg, int timo)
  95 {
  96         bp->b_lock.lk_wmesg = wmesg;
  97         bp->b_lock.lk_timo = timo;
  98         return (lockmgr(&(bp)->b_lock, locktype | LK_TIMELOCK));
  99 }
 100 /*
 101  * Release a lock. Only the acquiring process may free the lock unless
 102  * it has been handed off to biodone.
 103  */
 104 static __inline void
 105 BUF_UNLOCK(struct buf *bp)
 106 {
 107         lockmgr(&(bp)->b_lock, LK_RELEASE);
 108 }
 109
 110 /*
 111  * When initiating asynchronous I/O, change ownership of the lock to the
 112  * kernel. Once done, the lock may legally released by biodone. The
 113  * original owning process can no longer acquire it recursively, but must
 114  * wait until the I/O is completed and the lock has been freed by biodone.
 115  */
 116 static __inline void
 117 BUF_KERNPROC(struct buf *bp)
 118 {
 119         lockmgr_kernproc(&(bp)->b_lock);
 120 }
 121 /*
 122  * Find out the number of references to a lock.
 123  *
 124  * The non-blocking version should only be used for assertions in cases
 125  * where the buffer is expected to be owned or otherwise data stable.
 126  */
 127 static __inline int
 128 BUF_REFCNT(struct buf *bp)
 129 {
 130         return (lockcount(&(bp)->b_lock));
 131 }
 132
 133 static __inline int
 134 BUF_REFCNTNB(struct buf *bp)
 135 {
 136         return (lockcountnb(&(bp)->b_lock));
 137 }
 138
 139 /*
 140  * Free a buffer lock.
 141  */
 142 #define BUF_LOCKFREE(bp)                        \
 143         if (BUF_REFCNTNB(bp) > 0)               \
 144                 panic("free locked buf")
 145
 146 static __inline void
 147 bioq_init(struct bio_queue_head *bioq)
 148 {
 149         TAILQ_INIT(&bioq->queue);
 150         bioq->off_unused = 0;
 151         bioq->reorder = 0;
 152         bioq->transition = NULL;
 153         bioq->bio_unused = NULL;
 154 }
 155
 156 static __inline void
 157 bioq_insert_tail(struct bio_queue_head *bioq, struct bio *bio)
 158 {
 159         bioq->transition = NULL;
 160         TAILQ_INSERT_TAIL(&bioq->queue, bio, bio_act);
 161 }
 162
 163 static __inline void
 164 bioq_remove(struct bio_queue_head *bioq, struct bio *bio)
 165 {
 166         /*
 167          * Adjust read insertion point when removing the bioq.  The
 168          * bio after the insert point is a write so move backwards
 169          * one (NULL will indicate all the reads have cleared).
 170          */
 171         if (bio == bioq->transition)
 172                 bioq->transition = TAILQ_NEXT(bio, bio_act);
 173         TAILQ_REMOVE(&bioq->queue, bio, bio_act);
 174 }
 175
 176 static __inline struct bio *
 177 bioq_first(struct bio_queue_head *bioq)
 178 {
 179         return (TAILQ_FIRST(&bioq->queue));
 180 }
 181
 182 static __inline struct bio *
 183 bioq_takefirst(struct bio_queue_head *bioq)
 184 {
 185         struct bio *bp;
 186
 187         bp = TAILQ_FIRST(&bioq->queue);
 188         if (bp != NULL)
 189                 bioq_remove(bioq, bp);
 190         return (bp);
 191 }
 192
 193 /*
 194  * Adjust buffer cache buffer's activity count.  This
 195  * works similarly to vm_page->act_count.
 196  */
 197 static __inline void
 198 buf_act_advance(struct buf *bp)
 199 {
 200         if (bp->b_act_count > ACT_MAX - ACT_ADVANCE)
 201                 bp->b_act_count = ACT_MAX;
 202         else
 203                 bp->b_act_count += ACT_ADVANCE;
 204 }
 205
 206 static __inline void
 207 buf_act_decline(struct buf *bp)
 208 {
 209         if (bp->b_act_count < ACT_DECLINE)
 210                 bp->b_act_count = 0;
 211         else
 212                 bp->b_act_count -= ACT_DECLINE;
 213 }
 214
 215 /*
 216  * biodeps inlines - used by softupdates and HAMMER.
 217  *
 218  * All bioops are MPSAFE
 219  */
 220 static __inline void
 221 buf_dep_init(struct buf *bp)
 222 {
 223         bp->b_ops = NULL;
 224         LIST_INIT(&bp->b_dep);
 225 }
 226
 227 /*
 228  * Precondition: the buffer has some dependencies.
 229  *
 230  * MPSAFE
 231  */
 232 static __inline void
 233 buf_deallocate(struct buf *bp)
 234 {
 235         struct bio_ops *ops = bp->b_ops;
 236
 237         KKASSERT(! LIST_EMPTY(&bp->b_dep));
 238         if (ops)
 239                 ops->io_deallocate(bp);
 240 }
 241
 242 /*
 243  * MPSAFE
 244  */
 245 static __inline int
 246 buf_countdeps(struct buf *bp, int n)
 247 {
 248         struct bio_ops *ops = bp->b_ops;
 249         int r;
 250
 251         if (ops)
 252                 r = ops->io_countdeps(bp, n);
 253         else
 254                 r = 0;
 255         return(r);
 256 }
 257
 258 /*
 259  * MPSAFE
 260  */
 261 static __inline void
 262 buf_start(struct buf *bp)
 263 {
 264         struct bio_ops *ops = bp->b_ops;
 265
 266         if (ops)
 267                 ops->io_start(bp);
 268 }
 269
 270 /*
 271  * MPSAFE
 272  */
 273 static __inline void
 274 buf_complete(struct buf *bp)
 275 {
 276         struct bio_ops *ops = bp->b_ops;
 277
 278         if (ops)
 279                 ops->io_complete(bp);
 280 }
 281
 282 /*
 283  * MPSAFE
 284  */
 285 static __inline int
 286 buf_fsync(struct vnode *vp)
 287 {
 288         struct bio_ops *ops = vp->v_mount->mnt_bioops;
 289         int r;
 290
 291         if (ops)
 292                 r = ops->io_fsync(vp);
 293         else
 294                 r = 0;
 295         return(r);
 296 }
 297
 298 /*
 299  * MPSAFE
 300  */
 301 static __inline void
 302 buf_movedeps(struct buf *bp1, struct buf *bp2)
 303 {
 304         struct bio_ops *ops = bp1->b_ops;
 305
 306         if (ops)
 307                 ops->io_movedeps(bp1, bp2);
 308 }
 309
 310 /*
 311  * MPSAFE
 312  */
 313 static __inline int
 314 buf_checkread(struct buf *bp)
 315 {
 316         struct bio_ops *ops = bp->b_ops;
 317
 318         if (ops)
 319                 return(ops->io_checkread(bp));
 320         return(0);
 321 }
 322
 323 /*
 324  * MPSAFE
 325  */
 326 static __inline int
 327 buf_checkwrite(struct buf *bp)
 328 {
 329         struct bio_ops *ops = bp->b_ops;
 330
 331         if (ops)
 332                 return(ops->io_checkwrite(bp));
 333         return(0);
 334 }
 335
 336 /*
 337  * Chained biodone.  The bio callback was made and the callback function
 338  * wishes to chain the biodone.  If no BIO's are left we call bpdone()
 339  * with elseit=TRUE (asynchronous completion).
 340  *
 341  * MPSAFE
 342  */
 343 static __inline void
 344 biodone_chain(struct bio *bio)
 345 {
 346         if (bio->bio_prev)
 347                 biodone(bio->bio_prev);
 348         else
 349                 bpdone(bio->bio_buf, 1);
 350 }
 351
 352 static __inline int
 353 bread(struct vnode *vp, off_t loffset, int size, struct buf **bpp)
 354 {
 355         *bpp = NULL;
 356         return(breadnx(vp, loffset, size, NULL, NULL, 0, bpp));
 357 }
 358
 359
 360 static __inline int
 361 breadn(struct vnode *vp, off_t loffset, int size, off_t *raoffset,
 362       int *rabsize, int cnt, struct buf **bpp)
 363 {
 364         *bpp = NULL;
 365         return(breadnx(vp, loffset, size, raoffset, rabsize, cnt, bpp));
 366 }
 367
 368 static __inline int
 369 cluster_read(struct vnode *vp, off_t filesize, off_t loffset,
 370              int blksize, size_t minreq, size_t maxreq, struct buf **bpp)
 371 {
 372         *bpp = NULL;
 373         return(cluster_readx(vp, filesize, loffset, blksize, minreq,
 374                              maxreq, bpp));
 375 }
 376
 377 #endif /* _KERNEL */
 378
 379 #endif /* !_SYS_BUF2_H_ */