bsd/sys/buf_internal.h

   1 /*
   2  * Copyright (c) 2000-2002 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_LICENSE_HEADER_START@
   5  *
   6  * The contents of this file constitute Original Code as defined in and
   7  * are subject to the Apple Public Source License Version 1.1 (the
   8  * "License").  You may not use this file except in compliance with the
   9  * License.  Please obtain a copy of the License at
  10  * http://www.apple.com/publicsource and read it before using this file.
  11  *
  12  * This Original Code and all software distributed under the License are
  13  * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  14  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  15  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  16  * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT.  Please see the
  17  * License for the specific language governing rights and limitations
  18  * under the License.
  19  *
  20  * @APPLE_LICENSE_HEADER_END@
  21  */
  22 /* Copyright (c) 1995 NeXT Computer, Inc. All Rights Reserved */
  23 /*
  24  * Copyright (c) 1982, 1986, 1989, 1993
  25  *      The Regents of the University of California.  All rights reserved.
  26  * (c) UNIX System Laboratories, Inc.
  27  * All or some portions of this file are derived from material licensed
  28  * to the University of California by American Telephone and Telegraph
  29  * Co. or Unix System Laboratories, Inc. and are reproduced herein with
  30  * the permission of UNIX System Laboratories, Inc.
  31  *
  32  * Redistribution and use in source and binary forms, with or without
  33  * modification, are permitted provided that the following conditions
  34  * are met:
  35  * 1. Redistributions of source code must retain the above copyright
  36  *    notice, this list of conditions and the following disclaimer.
  37  * 2. Redistributions in binary form must reproduce the above copyright
  38  *    notice, this list of conditions and the following disclaimer in the
  39  *    documentation and/or other materials provided with the distribution.
  40  * 3. All advertising materials mentioning features or use of this software
  41  *    must display the following acknowledgement:
  42  *      This product includes software developed by the University of
  43  *      California, Berkeley and its contributors.
  44  * 4. Neither the name of the University nor the names of its contributors
  45  *    may be used to endorse or promote products derived from this software
  46  *    without specific prior written permission.
  47  *
  48  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  49  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  50  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  51  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  52  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  53  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  54  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  55  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  56  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  57  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  58  * SUCH DAMAGE.
  59  *
  60  *      @(#)buf.h       8.9 (Berkeley) 3/30/95
  61  */
  62
  63 #ifndef _SYS_BUF_INTERNAL_H_
  64 #define _SYS_BUF_INTERNAL_H_
  65
  66 #include <sys/appleapiopts.h>
  67
  68 #ifdef KERNEL
  69 #include <sys/queue.h>
  70 #include <sys/errno.h>
  71 #include <sys/vm.h>
  72 #include <sys/cdefs.h>
  73 #include <sys/buf.h>
  74 #include <sys/lock.h>
  75
  76
  77 #define NOLIST ((struct buf *)0x87654321)
  78
  79 /*
  80  * The buffer header describes an I/O operation in the kernel.
  81  */
  82 struct buf {
  83         LIST_ENTRY(buf) b_hash;         /* Hash chain. */
  84         LIST_ENTRY(buf) b_vnbufs;       /* Buffer's associated vnode. */
  85         TAILQ_ENTRY(buf) b_freelist;    /* Free list position if not active. */
  86         int     b_timestamp;            /* timestamp for queuing operation */
  87         long    b_whichq;               /* the free list the buffer belongs to */
  88         volatile long   b_flags;        /* B_* flags. */
  89         volatile long   b_lflags;       /* BL_BUSY | BL_WANTED flags... protected by buf_mtx */
  90         int     b_error;                /* errno value. */
  91         long    b_bufsize;              /* Allocated buffer size. */
  92         long    b_bcount;               /* Valid bytes in buffer. */
  93         long    b_resid;                /* Remaining I/O. */
  94         dev_t   b_dev;                  /* Device associated with buffer. */
  95         uintptr_t       b_datap;        /* Memory, superblocks, indirect etc.*/
  96         daddr64_t       b_lblkno;       /* Logical block number. */
  97         daddr64_t       b_blkno;        /* Underlying physical block number. */
  98         void    (*b_iodone)(buf_t, void *);     /* Function to call upon completion. */
  99         vnode_t b_vp;                   /* Device vnode. */
 100         struct  ucred *b_rcred;         /* Read credentials reference. */
 101         struct  ucred *b_wcred;         /* Write credentials reference. */
 102         void *  b_upl;                  /* Pointer to UPL */
 103         buf_t   b_real_bp;              /* used to track bp generated through cluster_bp */
 104         TAILQ_ENTRY(buf)        b_act;  /* Device driver queue when active */
 105         void *  b_drvdata;              /* Device driver private use */
 106         void *  b_fsprivate;            /* filesystem private use */
 107         void *  b_transaction;          /* journal private use */
 108         int     b_dirtyoff;             /* Offset in buffer of dirty region. */
 109         int     b_dirtyend;             /* Offset of end of dirty region. */
 110         int     b_validoff;             /* Offset in buffer of valid region. */
 111         int     b_validend;             /* Offset of end of valid region. */
 112         proc_t  b_proc;                 /* Associated proc; NULL if kernel. */
 113 #ifdef JOE_DEBUG
 114         void *  b_owner;
 115         int     b_tag;
 116         void *  b_lastbrelse;
 117         int     b_stackbrelse[6];
 118         int     b_stackgetblk[6];
 119 #endif
 120 };
 121
 122
 123 /* cluster_io definitions for use with io bufs */
 124 #define b_uploffset  b_bufsize
 125 #define b_trans_head b_freelist.tqe_prev
 126 #define b_trans_next b_freelist.tqe_next
 127 #define b_iostate    b_rcred
 128
 129 /*
 130  * These flags are kept in b_lflags...
 131  * buf_mtxp must be held before examining/updating
 132  */
 133 #define BL_BUSY         0x00000001      /* I/O in progress. */
 134 #define BL_WANTED       0x00000002      /* Process wants this buffer. */
 135 #define BL_IOBUF        0x00000004      /* buffer allocated via 'buf_alloc' */
 136
 137
 138 /*
 139  * mask used by buf_flags... these are the readable external flags
 140  */
 141 #define BUF_X_RDFLAGS (B_CLUSTER | B_PHYS | B_LOCKED | B_DELWRI | B_ASYNC |\
 142                        B_READ | B_WRITE | B_META | B_PAGEIO)
 143 /*
 144  * mask used by buf_clearflags/buf_setflags... these are the writable external flags
 145  */
 146 #define BUF_X_WRFLAGS (B_LOCKED | B_NOCACHE | B_ASYNC | B_READ | B_WRITE | B_PAGEIO)
 147
 148 /*
 149  * These flags are kept in b_flags... access is lockless
 150  * External flags are defined in buf.h and cannot overlap
 151  * the internal flags
 152  *
 153  * these flags are internal... there definition may change
 154  */
 155 #define B_CACHE         0x00010000      /* getblk found us in the cache. */
 156 #define B_DONE          0x00020000      /* I/O completed. */
 157 #define B_INVAL         0x00040000      /* Does not contain valid info. */
 158 #define B_ERROR         0x00080000      /* I/O error occurred. */
 159 #define B_EINTR         0x00100000      /* I/O was interrupted */
 160 #define B_AGE           0x00200000      /* Move to age queue when I/O done. */
 161 #define B_FILTER        0x00400000      /* call b_iodone from biodone as an in-line filter */
 162 #define B_CALL          0x00800000      /* Call b_iodone from biodone, assumes b_iodone consumes bp */
 163 #define B_RAW           0x01000000      /* Set by physio for raw transfers. */
 164 #define B_WASDIRTY      0x02000000      /* page was found dirty in the VM cache */
 165 #define B_HDRALLOC      0x04000000      /* zone allocated buffer header */
 166 #define B_ZALLOC        0x08000000      /* b_datap is zalloc()ed */
 167 /*
 168  * private flags used by the journal layer
 169  */
 170 #define B_NORELSE       0x10000000      /* don't brelse() in bwrite() */
 171 /*
 172  * private flags used by by the cluster layer
 173  */
 174 #define B_NEED_IODONE   0x20000000      /* need biodone on the real_bp associated with a cluster_io */
 175 #define B_COMMIT_UPL    0x40000000      /* commit/abort the UPL on I/O success/failure */
 176 /*
 177  * can we deprecate?
 178  */
 179 #define B_TAPE          0x80000000      /* Magnetic tape I/O. */
 180
 181
 182 /* Flags to low-level allocation routines. */
 183 #define B_CLRBUF        0x01    /* Request allocated buffer be cleared. */
 184 #define B_SYNC          0x02    /* Do all allocations synchronously. */
 185 #define B_NOBUFF        0x04    /* Do not allocate struct buf */
 186
 187
 188 extern int niobuf;              /* The number of IO buffer headers for cluster IO */
 189 extern int nbuf;                /* The number of buffer headers */
 190 extern struct buf *buf;         /* The buffer headers. */
 191 extern int max_nbuf_headers;            /* The max number of buffer headers */
 192 extern int nbuf_hashelements;           /* The number of elements in bufhash */
 193
 194
 195 /*
 196  * Definitions for the buffer free lists.
 197  */
 198 #define BQUEUES         6               /* number of free buffer queues */
 199
 200 #define BQ_LOCKED       0               /* super-blocks &c */
 201 #define BQ_LRU          1               /* lru, useful buffers */
 202 #define BQ_AGE          2               /* rubbish */
 203 #define BQ_EMPTY        3               /* buffer headers with no memory */
 204 #define BQ_META         4               /* buffer containing metadata */
 205 #define BQ_LAUNDRY      5               /* buffers that need cleaning */
 206
 207
 208 __BEGIN_DECLS
 209
 210 buf_t   alloc_io_buf(vnode_t, int);
 211 void    free_io_buf(buf_t);
 212
 213 int     allocbuf(struct buf *, int);
 214 void    bufinit(void);
 215
 216 void    buf_setfilter(buf_t, void (*)(buf_t, void *), void *, void **, void **);
 217
 218 /*
 219  * Flags for buf_acquire
 220  */
 221 #define BAC_NOWAIT              0x01    /* Don't wait if buffer is busy */
 222 #define BAC_REMOVE              0x02    /* Remove from free list once buffer is acquired */
 223 #define BAC_SKIP_NONLOCKED      0x04    /* Don't return LOCKED buffers */
 224 #define BAC_SKIP_LOCKED         0x08    /* Only return LOCKED buffers */
 225
 226 void    cluster_init(void);
 227 void    buf_drop(buf_t);
 228 errno_t buf_acquire(buf_t, int, int, int);
 229
 230 int     count_busy_buffers(void);
 231 int     count_lock_queue(void);
 232
 233
 234 __END_DECLS
 235
 236
 237 /*
 238  *      Stats on usefulness of the buffer cache
 239  */
 240 struct bufstats {
 241         long    bufs_incore;            /* found incore */
 242         long    bufs_busyincore;        /* found incore. was busy */
 243         long    bufs_vmhits;            /* not incore. found in VM */
 244         long    bufs_miss;                      /* not incore. not in VM */
 245         long    bufs_sleeps;            /* buffer starvation */
 246         long    bufs_eblk;                      /* Calls to geteblk */
 247         long    bufs_iobufmax;          /* Max. number of IO buffers used */
 248         long    bufs_iobufinuse;        /* number of IO buffers in use */
 249         long    bufs_iobufsleeps;       /* IO buffer starvation */
 250 };
 251
 252 #endif /* KERNEL */
 253 #endif /* !_SYS_BUF_H_ */