This is xnu-8019. See this file in:
/*
 * Copyright (c) 2000-2014 Apple Inc. All rights reserved.
 *
 * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
 *
 * This file contains Original Code and/or Modifications of Original Code
 * as defined in and that are subject to the Apple Public Source License
 * Version 2.0 (the 'License'). You may not use this file except in
 * compliance with the License. The rights granted to you under the License
 * may not be used to create, or enable the creation or redistribution of,
 * unlawful or unlicensed copies of an Apple operating system, or to
 * circumvent, violate, or enable the circumvention or violation of, any
 * terms of an Apple operating system software license agreement.
 *
 * Please obtain a copy of the License at
 * http://www.opensource.apple.com/apsl/ and read it before using this file.
 *
 * The Original Code and all software distributed under the License are
 * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
 * Please see the License for the specific language governing rights and
 * limitations under the License.
 *
 * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
 */
/* Copyright (c) 1995 NeXT Computer, Inc. All Rights Reserved */
/*
 * Copyright (c) 1982, 1986, 1989, 1993
 *	The Regents of the University of California.  All rights reserved.
 * (c) UNIX System Laboratories, Inc.
 * All or some portions of this file are derived from material licensed
 * to the University of California by American Telephone and Telegraph
 * Co. or Unix System Laboratories, Inc. and are reproduced herein with
 * the permission of UNIX System Laboratories, Inc.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *	This product includes software developed by the University of
 *	California, Berkeley and its contributors.
 * 4. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 *	@(#)buf.h	8.9 (Berkeley) 3/30/95
 */

#ifndef _SYS_BUF_INTERNAL_H_
#define _SYS_BUF_INTERNAL_H_

#include <sys/appleapiopts.h>

#ifdef KERNEL
#include <sys/queue.h>
#include <sys/errno.h>
#include <sys/vm.h>
#include <sys/cdefs.h>
#include <sys/buf.h>
#include <sys/lock.h>

#if CONFIG_PROTECT
#include <sys/cprotect.h>
#endif

#define NOLIST ((struct buf *)0x87654321)

/*
 * Attributes of an I/O to be used by lower layers
 */
struct bufattr {
#if CONFIG_PROTECT
	struct cpx *ba_cpx;
	uint64_t ba_cp_file_off;
#endif
	uint64_t ba_flags;      /* flags. Some are only in-use on embedded devices */
	void *ba_verify_ctx;
};

/*
 * The buffer header describes an I/O operation in the kernel.
 */
struct buf {
	LIST_ENTRY(buf) b_hash;         /* Hash chain. */
	LIST_ENTRY(buf) b_vnbufs;       /* Buffer's associated vnode. */
	TAILQ_ENTRY(buf) b_freelist;    /* Free list position if not active. */
	int     b_timestamp;            /* timestamp for queuing operation */
	struct timeval b_timestamp_tv; /* microuptime for disk conditioner */
	int     b_whichq;               /* the free list the buffer belongs to */
	volatile uint32_t       b_flags;        /* B_* flags. */
	volatile uint32_t       b_lflags;       /* BL_BUSY | BL_WANTED flags... protected by buf_mtx */
	int     b_error;                /* errno value. */
	int     b_bufsize;              /* Allocated buffer size. */
	int     b_bcount;               /* Valid bytes in buffer. */
	int     b_resid;                /* Remaining I/O. */
	dev_t   b_dev;                  /* Device associated with buffer. */
	uintptr_t       b_datap;        /* Memory, superblocks, indirect etc.*/
	daddr64_t       b_lblkno;       /* Logical block number. */
	daddr64_t       b_blkno;        /* Underlying physical block number. */
	void    (*b_iodone)(buf_t, void *);     /* Function to call upon completion. */
	vnode_t b_vp;                   /* File vnode for data, device vnode for metadata. */
	kauth_cred_t b_rcred;           /* Read credentials reference. */
	kauth_cred_t b_wcred;           /* Write credentials reference. */
	void *  b_upl;                  /* Pointer to UPL */
	buf_t   b_real_bp;              /* used to track bp generated through cluster_bp */
	TAILQ_ENTRY(buf)        b_act;  /* Device driver queue when active */
	void *  b_drvdata;              /* Device driver private use */
	void *  b_fsprivate;            /* filesystem private use */
	void *  b_transaction;          /* journal private use */
	int     b_dirtyoff;             /* Offset in buffer of dirty region. */
	int     b_dirtyend;             /* Offset of end of dirty region. */
	int     b_validoff;             /* Offset in buffer of valid region. */
	int     b_validend;             /* Offset of end of valid region. */

	/* store extra information related to redundancy of data, such as
	 * which redundancy copy to use, etc
	 */
	uint32_t b_redundancy_flags;

	proc_t  b_proc;                 /* Associated proc; NULL if kernel. */
#ifdef BUF_MAKE_PRIVATE
	buf_t   b_data_store;
#endif
	struct bufattr b_attr;
#ifdef JOE_DEBUG
	void *  b_owner;
	int     b_tag;
	void *  b_lastbrelse;
	void *  b_stackbrelse[6];
	void *  b_stackgetblk[6];
#endif
	uint32_t b_lblksize;          /* Block size used to set b_lbkno */
};

extern vm_offset_t buf_kernel_addrperm;

/* cluster_io definitions for use with io bufs */
#define b_uploffset  b_bufsize
#define b_orig       b_freelist.tqe_prev
#define b_shadow     b_freelist.tqe_next
#define b_shadow_ref b_validoff
#ifdef BUF_MAKE_PRIVATE
#define b_data_ref   b_validend
#endif
#define b_trans_head b_freelist.tqe_prev
#define b_trans_next b_freelist.tqe_next
#define b_iostate    b_rcred
#define b_cliodone   b_wcred

/*
 * These flags are kept in b_lflags...
 * buf_mtx must be held before examining/updating
 */
#define BL_BUSY         0x00000001      /* I/O in progress. */
#define BL_WANTED       0x00000002      /* Process wants this buffer. */
#define BL_IOBUF        0x00000004      /* buffer allocated via 'buf_alloc' */
#define BL_WANTDEALLOC  0x00000010      /* buffer should be put on empty list when clean */
#define BL_SHADOW       0x00000020
#define BL_EXTERNAL     0x00000040
#define BL_WAITSHADOW   0x00000080
#define BL_IOBUF_ALLOC  0x00000100
#define BL_WANTED_REF   0x00000200
#define BL_IOBUF_VDEV   0x00000400      /* iobuf was for a diskimage */

/*
 * Parameters for buffer cache garbage collection
 */
#define BUF_STALE_THRESHHOLD    30      /* Collect if untouched in the last 30 seconds */
#define BUF_MAX_GC_BATCH_SIZE   64      /* Under a single grab of the lock */

/*
 * mask used by buf_flags... these are the readable external flags
 */
#define BUF_X_RDFLAGS (B_PHYS | B_RAW | B_LOCKED | B_ASYNC | B_READ | B_WRITE | B_PAGEIO |\
	               B_META | B_CLUSTER | B_DELWRI | B_FUA | B_PASSIVE | B_IOSTREAMING |\
	               B_ENCRYPTED_IO | B_STATICCONTENT)
/*
 * mask used by buf_clearflags/buf_setflags... these are the writable external flags
 */
#define BUF_X_WRFLAGS (B_PHYS | B_RAW | B_LOCKED | B_ASYNC | B_READ | B_WRITE | B_PAGEIO |\
	               B_NOCACHE | B_FUA | B_PASSIVE | B_IOSTREAMING)

#if 0
/* b_flags defined in buf.h */
#define B_WRITE         0x00000000      /* Write buffer (pseudo flag). */
#define B_READ          0x00000001      /* Read buffer. */
#define B_ASYNC         0x00000002      /* Start I/O, do not wait. */
#define B_NOCACHE       0x00000004      /* Do not cache block after use. */
#define B_DELWRI        0x00000008      /* Delay I/O until buffer reused. */
#define B_LOCKED        0x00000010      /* Locked in core (not reusable). */
#define B_PHYS          0x00000020      /* I/O to user memory. */
#define B_CLUSTER       0x00000040      /* UPL based I/O generated by cluster layer */
#define B_PAGEIO        0x00000080      /* Page in/out */
#define B_META          0x00000100      /* buffer contains meta-data. */
#define B_RAW           0x00000200      /* Set by physio for raw transfers. */
#define B_FUA           0x00000400      /* Write-through disk cache(if supported) */
#define B_PASSIVE       0x00000800      /* PASSIVE I/Os are ignored by THROTTLE I/O */
#define B_IOSTREAMING   0x00001000      /* sequential access pattern detected */
#define B_ENCRYPTED_IO  0x00004000      /* Encrypted I/O */
#define B_STATICCONTENT 0x00008000      /* Buffer is likely to remain unaltered */
#endif

/*
 * These flags are kept in b_flags... access is lockless
 * External flags are defined in buf.h and cannot overlap
 * the internal flags
 *
 * these flags are internal... there definition may change
 */
#define B_CACHE         0x00010000      /* getblk found us in the cache. */
#define B_DONE          0x00020000      /* I/O completed. */
#define B_INVAL         0x00040000      /* Does not contain valid info. */
#define B_ERROR         0x00080000      /* I/O error occurred. */
#define B_EINTR         0x00100000      /* I/O was interrupted */
#define B_AGE           0x00200000      /* Move to age queue when I/O done. */
#define B_FILTER        0x00400000      /* call b_iodone from biodone as an in-line filter */
#define B_CALL          0x00800000      /* Call b_iodone from biodone, assumes b_iodone consumes bp */
#define B_EOT           0x01000000      /* last buffer in a transaction list created by cluster_io */
#define B_WASDIRTY      0x02000000      /* page was found dirty in the VM cache */
#define B_HDRALLOC      0x04000000      /* zone allocated buffer header */
#define B_ZALLOC        0x08000000      /* b_datap is zalloc()ed */
/*
 * private flags used by by the cluster layer
 */
#define B_COMMIT_UPL    0x40000000      /* commit/abort the UPL on I/O success/failure */
#define B_TDONE         0x80000000      /* buf_t that is part of a cluster level transaction has completed */

/* Flags to low-level allocation routines. */
#define B_CLRBUF        0x01    /* Request allocated buffer be cleared. */
#define B_SYNC          0x02    /* Do all allocations synchronously. */
#define B_NOBUFF        0x04    /* Do not allocate struct buf */

/*
 * ba_flags (Buffer Attribute flags)
 * Some of these may be in-use only on embedded devices.
 */
#define BA_RAW_ENCRYPTED_IO     0x00000001
#define BA_THROTTLED_IO         0x00000002
#define BA_DELAYIDLESLEEP       0x00000004      /* Process is marked to delay idle sleep on disk IO */
#define BA_NOCACHE              0x00000008
#define BA_META                 0x00000010
#define BA_GREEDY_MODE          0x00000020      /* High speed writes that consume more storage */
#define BA_QUICK_COMPLETE       0x00000040      /* Request quick completion at expense of storage efficiency */
#define BA_PASSIVE              0x00000080

/*
 * Note: IO_TIERs consume 0x0100, 0x0200, 0x0400, 0x0800
 * These are now in-use by the I/O tiering system.
 */
#define BA_IO_TIER_MASK         0x00000f00
#define BA_IO_TIER_SHIFT        8

#define BA_ISOCHRONOUS          0x00001000 /* device specific isochronous throughput to media */

#define BA_STRATEGY_TRACKED_IO  0x00002000 /* tracked by spec_strategy */
#define BA_IO_TIER_UPGRADE      0x00004000 /* effective I/O tier is higher than BA_IO_TIER */
#define BA_IO_SCHEDULED         0x00008000 /* buf is associated with a mount point that is io scheduled */
#define BA_EXPEDITED_META_IO    0x00010000 /* metadata I/O which needs a high I/O tier */
#define BA_WILL_VERIFY          0x00020000 /* Cluster layer will verify data */

#define GET_BUFATTR_IO_TIER(bap)        ((bap->ba_flags & BA_IO_TIER_MASK) >> BA_IO_TIER_SHIFT)
#define SET_BUFATTR_IO_TIER(bap, tier)                                          \
do {                                                                            \
	(bap)->ba_flags &= (~BA_IO_TIER_MASK);                                  \
	(bap)->ba_flags |= (((tier) << BA_IO_TIER_SHIFT) & BA_IO_TIER_MASK);    \
} while(0)

extern int niobuf_headers;              /* The number of IO buffer headers for cluster IO */
extern int nbuf_headers;                /* The number of buffer headers */
extern int max_nbuf_headers;            /* The max number of buffer headers */
extern int nbuf_hashelements;           /* The number of elements in bufhash */
extern struct buf *buf_headers;         /* The buffer headers. */


/*
 * Definitions for the buffer free lists.
 */

enum bq_opts {
	BQ_LOCKED   = 0,  /* super-blocks &c */
	BQ_LRU      = 1,  /* lru, useful buffers */
	BQ_AGE      = 2,  /* rubbish */
	BQ_EMPTY    = 3,  /* buffer headers with no memory */
	BQ_META     = 4,  /* buffer containing metadata */
	BQ_LAUNDRY  = 5,  /* buffers that need cleaning */
	BQUEUES     = 6   /* number of free buffer queues */
};

#define CLUSTER_IO_BLOCK_SIZE 0x1000

__BEGIN_DECLS

buf_t   alloc_io_buf(vnode_t, int);
void    free_io_buf(buf_t);

int     allocbuf(struct buf *, int);
void    bufinit(void);

void    buf_list_lock(void);
void    buf_list_unlock(void);

void    cluster_init(void);

uint32_t     count_busy_buffers(void);

int buf_flushdirtyblks_skipinfo(vnode_t, int, int, const char *);
void buf_wait_for_shadow_io(vnode_t, daddr64_t);

#ifdef BUF_MAKE_PRIVATE
errno_t buf_make_private(buf_t bp);
#endif

#ifdef CONFIG_PROTECT
void buf_setcpoff(buf_t, uint64_t);
#endif

__END_DECLS


/*
 *	Stats on usefulness of the buffer cache
 */
struct bufstats {
	long    bufs_incore;            /* found incore */
	long    bufs_busyincore;        /* found incore. was busy */
	long    bufs_vmhits;            /* not incore. found in VM */
	long    bufs_miss;                      /* not incore. not in VM */
	long    bufs_sleeps;            /* buffer starvation */
	long    bufs_eblk;                      /* Calls to geteblk */
	uint32_t    bufs_iobufmax;          /* Max. number of IO buffers used */
	uint32_t    bufs_iobufinuse;        /* number of IO buffers in use */
	long    bufs_iobufsleeps;       /* IO buffer starvation */
	long    bufs_iobufinuse_vdev;   /* number of IO buffers in use by
	                                 *  diskimages */
};

#endif /* KERNEL */
#endif /* !_SYS_BUF_H_ */