bsd/sys/buf_internal.h

   1 /*
   2  * Copyright (c) 2006 Apple Computer, Inc. All Rights Reserved.
   3  *
   4  * @APPLE_LICENSE_OSREFERENCE_HEADER_START@
   5  *
   6  * This file contains Original Code and/or Modifications of Original Code
   7  * as defined in and that are subject to the Apple Public Source License
   8  * Version 2.0 (the 'License'). You may not use this file except in
   9  * compliance with the License.  The rights granted to you under the
  10  * License may not be used to create, or enable the creation or
  11  * redistribution of, unlawful or unlicensed copies of an Apple operating
  12  * system, or to circumvent, violate, or enable the circumvention or
  13  * violation of, any terms of an Apple operating system software license
  14  * agreement.
  15  *
  16  * Please obtain a copy of the License at
  17  * http://www.opensource.apple.com/apsl/ and read it before using this
  18  * file.
  19  *
  20  * The Original Code and all software distributed under the License are
  21  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  22  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  23  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  24  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  25  * Please see the License for the specific language governing rights and
  26  * limitations under the License.
  27  *
  28  * @APPLE_LICENSE_OSREFERENCE_HEADER_END@
  29  */
  30 /* Copyright (c) 1995 NeXT Computer, Inc. All Rights Reserved */
  31 /*
  32  * Copyright (c) 1982, 1986, 1989, 1993
  33  *      The Regents of the University of California.  All rights reserved.
  34  * (c) UNIX System Laboratories, Inc.
  35  * All or some portions of this file are derived from material licensed
  36  * to the University of California by American Telephone and Telegraph
  37  * Co. or Unix System Laboratories, Inc. and are reproduced herein with
  38  * the permission of UNIX System Laboratories, Inc.
  39  *
  40  * Redistribution and use in source and binary forms, with or without
  41  * modification, are permitted provided that the following conditions
  42  * are met:
  43  * 1. Redistributions of source code must retain the above copyright
  44  *    notice, this list of conditions and the following disclaimer.
  45  * 2. Redistributions in binary form must reproduce the above copyright
  46  *    notice, this list of conditions and the following disclaimer in the
  47  *    documentation and/or other materials provided with the distribution.
  48  * 3. All advertising materials mentioning features or use of this software
  49  *    must display the following acknowledgement:
  50  *      This product includes software developed by the University of
  51  *      California, Berkeley and its contributors.
  52  * 4. Neither the name of the University nor the names of its contributors
  53  *    may be used to endorse or promote products derived from this software
  54  *    without specific prior written permission.
  55  *
  56  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  57  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  58  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  59  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  60  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  61  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  62  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  63  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  64  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  65  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  66  * SUCH DAMAGE.
  67  *
  68  *      @(#)buf.h       8.9 (Berkeley) 3/30/95
  69  */
  70
  71 #ifndef _SYS_BUF_INTERNAL_H_
  72 #define _SYS_BUF_INTERNAL_H_
  73
  74 #include <sys/appleapiopts.h>
  75
  76 #ifdef KERNEL
  77 #include <sys/queue.h>
  78 #include <sys/errno.h>
  79 #include <sys/vm.h>
  80 #include <sys/cdefs.h>
  81 #include <sys/buf.h>
  82 #include <sys/lock.h>
  83
  84
  85 extern lck_mtx_t    *buf_mtxp;
  86 #define NOLIST ((struct buf *)0x87654321)
  87
  88 /*
  89  * The buffer header describes an I/O operation in the kernel.
  90  */
  91 struct buf {
  92         LIST_ENTRY(buf) b_hash;         /* Hash chain. */
  93         LIST_ENTRY(buf) b_vnbufs;       /* Buffer's associated vnode. */
  94         TAILQ_ENTRY(buf) b_freelist;    /* Free list position if not active. */
  95         int     b_timestamp;            /* timestamp for queuing operation */
  96         long    b_whichq;               /* the free list the buffer belongs to */
  97         volatile long   b_flags;        /* B_* flags. */
  98         volatile long   b_lflags;       /* BL_BUSY | BL_WANTED flags... protected by buf_mtx */
  99         int     b_error;                /* errno value. */
 100         long    b_bufsize;              /* Allocated buffer size. */
 101         long    b_bcount;               /* Valid bytes in buffer. */
 102         long    b_resid;                /* Remaining I/O. */
 103         dev_t   b_dev;                  /* Device associated with buffer. */
 104         uintptr_t       b_datap;        /* Memory, superblocks, indirect etc.*/
 105         daddr64_t       b_lblkno;       /* Logical block number. */
 106         daddr64_t       b_blkno;        /* Underlying physical block number. */
 107         void    (*b_iodone)(buf_t, void *);     /* Function to call upon completion. */
 108         vnode_t b_vp;                   /* Device vnode. */
 109         struct  ucred *b_rcred;         /* Read credentials reference. */
 110         struct  ucred *b_wcred;         /* Write credentials reference. */
 111         void *  b_upl;                  /* Pointer to UPL */
 112         buf_t   b_real_bp;              /* used to track bp generated through cluster_bp */
 113         TAILQ_ENTRY(buf)        b_act;  /* Device driver queue when active */
 114         void *  b_drvdata;              /* Device driver private use */
 115         void *  b_fsprivate;            /* filesystem private use */
 116         void *  b_transaction;          /* journal private use */
 117         int     b_dirtyoff;             /* Offset in buffer of dirty region. */
 118         int     b_dirtyend;             /* Offset of end of dirty region. */
 119         int     b_validoff;             /* Offset in buffer of valid region. */
 120         int     b_validend;             /* Offset of end of valid region. */
 121         proc_t  b_proc;                 /* Associated proc; NULL if kernel. */
 122 #ifdef JOE_DEBUG
 123         void *  b_owner;
 124         int     b_tag;
 125         void *  b_lastbrelse;
 126         int     b_stackbrelse[6];
 127         int     b_stackgetblk[6];
 128 #endif
 129 };
 130
 131
 132 /* cluster_io definitions for use with io bufs */
 133 #define b_uploffset  b_bufsize
 134 #define b_trans_head b_freelist.tqe_prev
 135 #define b_trans_next b_freelist.tqe_next
 136 #define b_iostate    b_rcred
 137
 138 /*
 139  * These flags are kept in b_lflags...
 140  * buf_mtxp must be held before examining/updating
 141  */
 142 #define BL_BUSY         0x00000001      /* I/O in progress. */
 143 #define BL_WANTED       0x00000002      /* Process wants this buffer. */
 144 #define BL_IOBUF        0x00000004      /* buffer allocated via 'buf_alloc' */
 145
 146
 147 /*
 148  * mask used by buf_flags... these are the readable external flags
 149  */
 150 #define BUF_X_RDFLAGS (B_CLUSTER | B_PHYS | B_LOCKED | B_DELWRI | B_ASYNC |\
 151                        B_READ | B_WRITE | B_META | B_PAGEIO)
 152 /*
 153  * mask used by buf_clearflags/buf_setflags... these are the writable external flags
 154  */
 155 #define BUF_X_WRFLAGS (B_LOCKED | B_NOCACHE | B_ASYNC | B_READ | B_WRITE | B_PAGEIO)
 156
 157 /*
 158  * These flags are kept in b_flags... access is lockless
 159  * External flags are defined in buf.h and cannot overlap
 160  * the internal flags
 161  *
 162  * these flags are internal... there definition may change
 163  */
 164 #define B_CACHE         0x00010000      /* getblk found us in the cache. */
 165 #define B_DONE          0x00020000      /* I/O completed. */
 166 #define B_INVAL         0x00040000      /* Does not contain valid info. */
 167 #define B_ERROR         0x00080000      /* I/O error occurred. */
 168 #define B_EINTR         0x00100000      /* I/O was interrupted */
 169 #define B_AGE           0x00200000      /* Move to age queue when I/O done. */
 170 #define B_FILTER        0x00400000      /* call b_iodone from biodone as an in-line filter */
 171 #define B_CALL          0x00800000      /* Call b_iodone from biodone, assumes b_iodone consumes bp */
 172 #define B_RAW           0x01000000      /* Set by physio for raw transfers. */
 173 #define B_WASDIRTY      0x02000000      /* page was found dirty in the VM cache */
 174 #define B_HDRALLOC      0x04000000      /* zone allocated buffer header */
 175 #define B_ZALLOC        0x08000000      /* b_datap is zalloc()ed */
 176 /*
 177  * private flags used by the journal layer
 178  */
 179 #define B_NORELSE       0x10000000      /* don't brelse() in bwrite() */
 180 /*
 181  * private flags used by by the cluster layer
 182  */
 183 #define B_NEED_IODONE   0x20000000      /* need biodone on the real_bp associated with a cluster_io */
 184 #define B_COMMIT_UPL    0x40000000      /* commit/abort the UPL on I/O success/failure */
 185 /*
 186  * can we deprecate?
 187  */
 188 #define B_TAPE          0x80000000      /* Magnetic tape I/O. */
 189
 190
 191 /* Flags to low-level allocation routines. */
 192 #define B_CLRBUF        0x01    /* Request allocated buffer be cleared. */
 193 #define B_SYNC          0x02    /* Do all allocations synchronously. */
 194 #define B_NOBUFF        0x04    /* Do not allocate struct buf */
 195
 196
 197 extern int niobuf;              /* The number of IO buffer headers for cluster IO */
 198 extern int nbuf;                /* The number of buffer headers */
 199 extern struct buf *buf;         /* The buffer headers. */
 200
 201
 202 /*
 203  * Definitions for the buffer free lists.
 204  */
 205 #define BQUEUES         6               /* number of free buffer queues */
 206
 207 #define BQ_LOCKED       0               /* super-blocks &c */
 208 #define BQ_LRU          1               /* lru, useful buffers */
 209 #define BQ_AGE          2               /* rubbish */
 210 #define BQ_EMPTY        3               /* buffer headers with no memory */
 211 #define BQ_META         4               /* buffer containing metadata */
 212 #define BQ_LAUNDRY      5               /* buffers that need cleaning */
 213
 214
 215 __BEGIN_DECLS
 216
 217 buf_t   alloc_io_buf(vnode_t, int);
 218 void    free_io_buf(buf_t);
 219
 220 int     allocbuf(struct buf *, int);
 221 void    bufinit(void);
 222
 223 void    buf_setfilter(buf_t, void (*)(buf_t, void *), void *, void **, void **);
 224
 225 /*
 226  * Flags for buf_acquire
 227  */
 228 #define BAC_NOWAIT              0x01    /* Don't wait if buffer is busy */
 229 #define BAC_REMOVE              0x02    /* Remove from free list once buffer is acquired */
 230 #define BAC_SKIP_NONLOCKED      0x04    /* Don't return LOCKED buffers */
 231 #define BAC_SKIP_LOCKED         0x08    /* Only return LOCKED buffers */
 232
 233 void    cluster_init(void);
 234 void    buf_drop(buf_t);
 235 errno_t buf_acquire(buf_t, int, int, int);
 236
 237 int     count_busy_buffers(void);
 238 int     count_lock_queue(void);
 239
 240
 241 __END_DECLS
 242
 243
 244 /*
 245  *      Stats on usefulness of the buffer cache
 246  */
 247 struct bufstats {
 248         long    bufs_incore;            /* found incore */
 249         long    bufs_busyincore;        /* found incore. was busy */
 250         long    bufs_vmhits;            /* not incore. found in VM */
 251         long    bufs_miss;                      /* not incore. not in VM */
 252         long    bufs_sleeps;            /* buffer starvation */
 253         long    bufs_eblk;                      /* Calls to geteblk */
 254         long    bufs_iobufmax;          /* Max. number of IO buffers used */
 255         long    bufs_iobufinuse;        /* number of IO buffers in use */
 256         long    bufs_iobufsleeps;       /* IO buffer starvation */
 257 };
 258
 259 #endif /* KERNEL */
 260 #endif /* !_SYS_BUF_H_ */