bsd/sys/buf_internal.h

   1 /*
   2  * Copyright (c) 2000-2008 Apple Inc. All rights reserved.
   3  *
   4  * @APPLE_OSREFERENCE_LICENSE_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 License
  10  * may not be used to create, or enable the creation or redistribution of,
  11  * unlawful or unlicensed copies of an Apple operating system, or to
  12  * circumvent, violate, or enable the circumvention or violation of, any
  13  * terms of an Apple operating system software license agreement.
  14  *
  15  * Please obtain a copy of the License at
  16  * http://www.opensource.apple.com/apsl/ and read it before using this file.
  17  *
  18  * The Original Code and all software distributed under the License are
  19  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  20  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  21  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  22  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  23  * Please see the License for the specific language governing rights and
  24  * limitations under the License.
  25  *
  26  * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
  27  */
  28 /* Copyright (c) 1995 NeXT Computer, Inc. All Rights Reserved */
  29 /*
  30  * Copyright (c) 1982, 1986, 1989, 1993
  31  *      The Regents of the University of California.  All rights reserved.
  32  * (c) UNIX System Laboratories, Inc.
  33  * All or some portions of this file are derived from material licensed
  34  * to the University of California by American Telephone and Telegraph
  35  * Co. or Unix System Laboratories, Inc. and are reproduced herein with
  36  * the permission of UNIX System Laboratories, Inc.
  37  *
  38  * Redistribution and use in source and binary forms, with or without
  39  * modification, are permitted provided that the following conditions
  40  * are met:
  41  * 1. Redistributions of source code must retain the above copyright
  42  *    notice, this list of conditions and the following disclaimer.
  43  * 2. Redistributions in binary form must reproduce the above copyright
  44  *    notice, this list of conditions and the following disclaimer in the
  45  *    documentation and/or other materials provided with the distribution.
  46  * 3. All advertising materials mentioning features or use of this software
  47  *    must display the following acknowledgement:
  48  *      This product includes software developed by the University of
  49  *      California, Berkeley and its contributors.
  50  * 4. Neither the name of the University nor the names of its contributors
  51  *    may be used to endorse or promote products derived from this software
  52  *    without specific prior written permission.
  53  *
  54  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  55  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  56  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  57  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  58  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  59  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  60  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  61  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  62  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  63  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  64  * SUCH DAMAGE.
  65  *
  66  *      @(#)buf.h       8.9 (Berkeley) 3/30/95
  67  */
  68
  69 #ifndef _SYS_BUF_INTERNAL_H_
  70 #define _SYS_BUF_INTERNAL_H_
  71
  72 #include <sys/appleapiopts.h>
  73
  74 #ifdef KERNEL
  75 #include <sys/queue.h>
  76 #include <sys/errno.h>
  77 #include <sys/vm.h>
  78 #include <sys/cdefs.h>
  79 #include <sys/buf.h>
  80 #include <sys/lock.h>
  81
  82
  83 #define NOLIST ((struct buf *)0x87654321)
  84
  85 /*
  86  * The buffer header describes an I/O operation in the kernel.
  87  */
  88 struct buf {
  89         LIST_ENTRY(buf) b_hash;         /* Hash chain. */
  90         LIST_ENTRY(buf) b_vnbufs;       /* Buffer's associated vnode. */
  91         TAILQ_ENTRY(buf) b_freelist;    /* Free list position if not active. */
  92         int     b_timestamp;            /* timestamp for queuing operation */
  93         int     b_whichq;               /* the free list the buffer belongs to */
  94         volatile uint32_t       b_flags;        /* B_* flags. */
  95         volatile uint32_t       b_lflags;       /* BL_BUSY | BL_WANTED flags... protected by buf_mtx */
  96         int     b_error;                /* errno value. */
  97         int     b_bufsize;              /* Allocated buffer size. */
  98         int     b_bcount;               /* Valid bytes in buffer. */
  99         int     b_resid;                /* Remaining I/O. */
 100         dev_t   b_dev;                  /* Device associated with buffer. */
 101         uintptr_t       b_datap;        /* Memory, superblocks, indirect etc.*/
 102         daddr64_t       b_lblkno;       /* Logical block number. */
 103         daddr64_t       b_blkno;        /* Underlying physical block number. */
 104         void    (*b_iodone)(buf_t, void *);     /* Function to call upon completion. */
 105         vnode_t b_vp;                   /* File vnode for data, device vnode for metadata. */
 106         kauth_cred_t b_rcred;           /* Read credentials reference. */
 107         kauth_cred_t b_wcred;           /* Write credentials reference. */
 108         void *  b_upl;                  /* Pointer to UPL */
 109         buf_t   b_real_bp;              /* used to track bp generated through cluster_bp */
 110         TAILQ_ENTRY(buf)        b_act;  /* Device driver queue when active */
 111         void *  b_drvdata;              /* Device driver private use */
 112         void *  b_fsprivate;            /* filesystem private use */
 113         void *  b_transaction;          /* journal private use */
 114         int     b_dirtyoff;             /* Offset in buffer of dirty region. */
 115         int     b_dirtyend;             /* Offset of end of dirty region. */
 116         int     b_validoff;             /* Offset in buffer of valid region. */
 117         int     b_validend;             /* Offset of end of valid region. */
 118         proc_t  b_proc;                 /* Associated proc; NULL if kernel. */
 119 #if CONFIG_PROTECT
 120         struct cprotect *b_cpentry;     /* address of cp_entry, to be passed further down  */
 121 #endif /* CONFIG_PROTECT */
 122 #ifdef JOE_DEBUG
 123         void *  b_owner;
 124         int     b_tag;
 125         void *  b_lastbrelse;
 126         void *  b_stackbrelse[6];
 127         void *  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 #define b_cliodone   b_wcred
 138
 139 /*
 140  * These flags are kept in b_lflags...
 141  * buf_mtxp must be held before examining/updating
 142  */
 143 #define BL_BUSY         0x00000001      /* I/O in progress. */
 144 #define BL_WANTED       0x00000002      /* Process wants this buffer. */
 145 #define BL_IOBUF        0x00000004      /* buffer allocated via 'buf_alloc' */
 146 #define BL_CALLDONE     0x00000008      /* callback routine on B_CALL bp has completed */
 147 #define BL_WANTDEALLOC  0x00000010      /* buffer should be put on empty list when clean */
 148
 149 /*
 150  * Parameters for buffer cache garbage collection
 151  */
 152 #define BUF_STALE_THRESHHOLD    30      /* Collect if untouched in the last 30 seconds */
 153 #define BUF_MAX_GC_COUNT        1000    /* Generally 6-8 MB */
 154
 155 /*
 156  * mask used by buf_flags... these are the readable external flags
 157  */
 158 #define BUF_X_RDFLAGS (B_PHYS | B_RAW | B_LOCKED | B_ASYNC | B_READ | B_WRITE | B_PAGEIO |\
 159                        B_META | B_CLUSTER | B_DELWRI | B_FUA | B_PASSIVE | B_IOSTREAMING | B_THROTTLED_IO)
 160 /*
 161  * mask used by buf_clearflags/buf_setflags... these are the writable external flags
 162  */
 163 #define BUF_X_WRFLAGS (B_PHYS | B_RAW | B_LOCKED | B_ASYNC | B_READ | B_WRITE | B_PAGEIO |\
 164                        B_NOCACHE | B_FUA | B_PASSIVE | B_IOSTREAMING)
 165
 166 /*
 167  * These flags are kept in b_flags... access is lockless
 168  * External flags are defined in buf.h and cannot overlap
 169  * the internal flags
 170  *
 171  * these flags are internal... there definition may change
 172  */
 173 #define B_CACHE         0x00010000      /* getblk found us in the cache. */
 174 #define B_DONE          0x00020000      /* I/O completed. */
 175 #define B_INVAL         0x00040000      /* Does not contain valid info. */
 176 #define B_ERROR         0x00080000      /* I/O error occurred. */
 177 #define B_EINTR         0x00100000      /* I/O was interrupted */
 178 #define B_AGE           0x00200000      /* Move to age queue when I/O done. */
 179 #define B_FILTER        0x00400000      /* call b_iodone from biodone as an in-line filter */
 180 #define B_CALL          0x00800000      /* Call b_iodone from biodone, assumes b_iodone consumes bp */
 181 #define B_EOT           0x01000000      /* last buffer in a transaction list created by cluster_io */
 182 #define B_WASDIRTY      0x02000000      /* page was found dirty in the VM cache */
 183 #define B_HDRALLOC      0x04000000      /* zone allocated buffer header */
 184 #define B_ZALLOC        0x08000000      /* b_datap is zalloc()ed */
 185 /*
 186  * private flags used by the journal layer
 187  */
 188 #define B_NORELSE       0x10000000      /* don't brelse() in bwrite() */
 189 /*
 190  * private flags used by by the cluster layer
 191  */
 192 #define B_NEED_IODONE   0x20000000      /* need biodone on the real_bp associated with a cluster_io */
 193 #define B_COMMIT_UPL    0x40000000      /* commit/abort the UPL on I/O success/failure */
 194
 195
 196 /* Flags to low-level allocation routines. */
 197 #define B_CLRBUF        0x01    /* Request allocated buffer be cleared. */
 198 #define B_SYNC          0x02    /* Do all allocations synchronously. */
 199 #define B_NOBUFF        0x04    /* Do not allocate struct buf */
 200
 201
 202 extern int niobuf_headers;              /* The number of IO buffer headers for cluster IO */
 203 extern int nbuf_headers;                /* The number of buffer headers */
 204 extern int max_nbuf_headers;            /* The max number of buffer headers */
 205 extern int nbuf_hashelements;           /* The number of elements in bufhash */
 206 extern struct buf *buf_headers;         /* The buffer headers. */
 207
 208
 209 /*
 210  * Definitions for the buffer free lists.
 211  */
 212 #define BQUEUES         6               /* number of free buffer queues */
 213
 214 #define BQ_LOCKED       0               /* super-blocks &c */
 215 #define BQ_LRU          1               /* lru, useful buffers */
 216 #define BQ_AGE          2               /* rubbish */
 217 #define BQ_EMPTY        3               /* buffer headers with no memory */
 218 #define BQ_META         4               /* buffer containing metadata */
 219 #define BQ_LAUNDRY      5               /* buffers that need cleaning */
 220
 221
 222 __BEGIN_DECLS
 223
 224 buf_t   alloc_io_buf(vnode_t, int);
 225 void    free_io_buf(buf_t);
 226
 227 int     allocbuf(struct buf *, int);
 228 void    bufinit(void) __attribute__((section("__TEXT, initcode")));
 229
 230 /*
 231  * Flags for buf_acquire
 232  */
 233 #define BAC_NOWAIT              0x01    /* Don't wait if buffer is busy */
 234 #define BAC_REMOVE              0x02    /* Remove from free list once buffer is acquired */
 235 #define BAC_SKIP_NONLOCKED      0x04    /* Don't return LOCKED buffers */
 236 #define BAC_SKIP_LOCKED         0x08    /* Only return LOCKED buffers */
 237
 238 void    buf_list_lock(void);
 239 void    buf_list_unlock(void);
 240
 241 void    buf_biowait_callback(buf_t);
 242
 243 void    cluster_init(void) __attribute__((section("__TEXT, initcode")));
 244 void    buf_drop(buf_t);
 245 errno_t buf_acquire(buf_t, int, int, int);
 246
 247 int     count_busy_buffers(void);
 248 int     count_lock_queue(void);
 249
 250
 251 __END_DECLS
 252
 253
 254 /*
 255  *      Stats on usefulness of the buffer cache
 256  */
 257 struct bufstats {
 258         long    bufs_incore;            /* found incore */
 259         long    bufs_busyincore;        /* found incore. was busy */
 260         long    bufs_vmhits;            /* not incore. found in VM */
 261         long    bufs_miss;                      /* not incore. not in VM */
 262         long    bufs_sleeps;            /* buffer starvation */
 263         long    bufs_eblk;                      /* Calls to geteblk */
 264         long    bufs_iobufmax;          /* Max. number of IO buffers used */
 265         long    bufs_iobufinuse;        /* number of IO buffers in use */
 266         long    bufs_iobufsleeps;       /* IO buffer starvation */
 267 };
 268
 269 #endif /* KERNEL */
 270 #endif /* !_SYS_BUF_H_ */