LCOM1920-T02G10

/*     $NetBSD: buf.h,v 1.121 2015/03/28 19:24:04 maxv Exp $ */

/*-

 * Copyright (c) 1999, 2000, 2007, 2008 The NetBSD Foundation, Inc.

 * All rights reserved.

 *

 * This code is derived from software contributed to The NetBSD Foundation

 * by Jason R. Thorpe of the Numerical Aerospace Simulation Facility,

 * NASA Ames Research Center, and by Andrew Doran.

 *

 * 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.

 *

 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. 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 FOUNDATION 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.

 */

/*

 * 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. 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_H_

#define        _SYS_BUF_H_

#include <sys/pool.h>

#include <sys/queue.h>

#include <sys/mutex.h>

#include <sys/condvar.h>

#include <sys/rbtree.h>

#if defined(_KERNEL)

#include <sys/workqueue.h>

#endif /* defined(_KERNEL) */

struct buf;

struct mount;

struct vnode;

struct kauth_cred;

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

extern kmutex_t bufcache_lock;

extern kmutex_t buffer_lock;

/*

 * The buffer header describes an I/O operation in the kernel.

 *

 * Field markings and the corresponding locks:

 *

 * b        thread of execution that holds BC_BUSY, does not correspond

 *          directly to any particular LWP

 * c        bufcache_lock

 * o        b_objlock

 *

 * For buffers associated with a vnode, b_objlock points to vp->v_interlock.

 * If not associated with a vnode, it points to the generic buffer_lock.

 */

struct buf {

        union {

                TAILQ_ENTRY(buf) u_actq;

                rb_node_t u_rbnode;

#if defined(_KERNEL) /* u_work is smaller than u_actq. XXX */

                struct work u_work;

#endif /* defined(_KERNEL) */

        } b_u;                                        /* b: device driver queue */

#define        b_actq        b_u.u_actq

#define        b_work        b_u.u_work

        void                        (*b_iodone)(struct buf *);/* b: call when done */

        int                        b_error;        /* b: errno value. */

        int                        b_resid;        /* b: remaining I/O. */

        u_int                        b_flags;        /* b: B_* flags */

        int                        b_prio;                /* b: priority for queue */

        int                        b_bufsize;        /* b: allocated size */

        int                        b_bcount;        /* b: valid bytes in buffer */

        dev_t                        b_dev;                /* b: associated device */

        void                        *b_data;        /* b: fs private data */

        daddr_t                        b_blkno;        /* b: physical block number

                                                      (partition relative) */

        daddr_t                        b_rawblkno;        /* b: raw physical block number

                                                      (volume relative) */

        struct proc                *b_proc;        /* b: proc if BB_PHYS */

        void                        *b_saveaddr;        /* b: saved b_data for physio */

        /*

         * b: private data for owner.

         *  - buffer cache buffers are owned by corresponding filesystem.

         *  - non-buffer cache buffers are owned by subsystem which

         *    allocated them. (filesystem, disk driver, etc)

         */

        void        *b_private;

        off_t        b_dcookie;                /* NFS: Offset cookie if dir block */

        kcondvar_t                b_busy;                /* c: threads waiting on buf */

        u_int                        b_refcnt;        /* c: refcount for b_busy */

        void                        *b_unused;        /*  : unused */

        LIST_ENTRY(buf)                b_hash;                /* c: hash chain */

        LIST_ENTRY(buf)                b_vnbufs;        /* c: associated vnode */

        TAILQ_ENTRY(buf)        b_freelist;        /* c: position if not active */

        LIST_ENTRY(buf)                b_wapbllist;        /* c: transaction buffer list */

        daddr_t                        b_lblkno;        /* c: logical block number */

        int                        b_freelistindex;/* c: free list index (BQ_) */

        u_int                        b_cflags;        /* c: BC_* flags */

        struct vnode                *b_vp;                /* c: file vnode */

        kcondvar_t                b_done;                /* o: waiting on completion */

        u_int                        b_oflags;        /* o: BO_* flags */

        kmutex_t                *b_objlock;        /* o: completion lock */

};

/*

 * For portability with historic industry practice, the cylinder number has

 * to be maintained in the `b_resid' field.

 */

#define        b_cylinder b_resid                /* Cylinder number for disksort(). */

/*

 * These flags are kept in b_cflags (owned by buffer cache).

 */

#define        BC_AGE                0x00000001        /* Move to age queue when I/O done. */

#define        BC_BUSY                0x00000010        /* I/O in progress. */

#define        BC_INVAL        0x00002000        /* Does not contain valid info. */

#define        BC_NOCACHE        0x00008000        /* Do not cache block after use. */

#define        BC_WANTED        0x00800000        /* Process wants this buffer. */

#define        BC_VFLUSH        0x04000000        /* Buffer is being synced. */

/*

 * These flags are kept in b_oflags (owned by associated object).

 */

#define        BO_DELWRI        0x00000080        /* Delay I/O until buffer reused. */

#define        BO_DONE                0x00000200        /* I/O completed. */

/*

 * These flags are kept in b_flags (owned by buffer holder).

 */

#define        B_WRITE                0x00000000        /* Write buffer (pseudo flag). */

#define        B_ASYNC                0x00000004        /* Start I/O, do not wait. */

#define        B_COWDONE        0x00000400        /* Copy-on-write already done. */

#define        B_GATHERED        0x00001000        /* LFS: already in a segment. */

#define        B_LOCKED        0x00004000        /* Locked in core (not reusable). */

#define        B_PHYS                0x00040000        /* I/O to user memory. */

#define        B_RAW                0x00080000        /* Set by physio for raw transfers. */

#define        B_READ                0x00100000        /* Read buffer. */

#define        B_DEVPRIVATE        0x02000000        /* Device driver private flag. */

#define BUF_FLAGBITS \

    "\20\1AGE\3ASYNC\4BAD\5BUSY\10DELWRI" \

    "\12DONE\13COWDONE\15GATHERED\16INVAL\17LOCKED\20NOCACHE" \

    "\23PHYS\24RAW\25READ\32DEVPRIVATE\33VFLUSH"

/* Avoid weird code due to B_WRITE being a "pseudo flag" */

#define BUF_ISREAD(bp)        (((bp)->b_flags & B_READ) == B_READ)

#define BUF_ISWRITE(bp)        (((bp)->b_flags & B_READ) == B_WRITE)

/*

 * This structure describes a clustered I/O.  It is stored in the b_saveaddr

 * field of the buffer on which I/O is done.  At I/O completion, cluster

 * callback uses the structure to parcel I/O's to individual buffers, and

 * then free's this structure.

 */

struct cluster_save {

        long        bs_bcount;                /* Saved b_bcount. */

        long        bs_bufsize;                /* Saved b_bufsize. */

        void        *bs_saveaddr;                /* Saved b_addr. */

        int        bs_nchildren;                /* Number of associated buffers. */

        struct buf *bs_children;        /* List of associated buffers. */

};

/*

 * Zero out the buffer's data area.

 */

#define        clrbuf(bp)                                                        \

do {                                                                        \

        memset((bp)->b_data, 0, (u_int)(bp)->b_bcount);                        \

        (bp)->b_resid = 0;                                                \

} while (/* CONSTCOND */ 0)

/* 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_METAONLY        0x04        /* Return indirect block buffer. */

#define B_CONTIG        0x08        /* Allocate file contiguously. */

/* Flags to bread() and breadn(). */

#define B_MODIFY        0x01        /* Hint: caller might modify buffer */

#ifdef _KERNEL

#define        BIO_GETPRIO(bp)                ((bp)->b_prio)

#define        BIO_SETPRIO(bp, prio)        (bp)->b_prio = (prio)

#define        BIO_COPYPRIO(bp1, bp2)        BIO_SETPRIO(bp1, BIO_GETPRIO(bp2))

#define        BPRIO_NPRIO                3

#define        BPRIO_TIMECRITICAL        2

#define        BPRIO_TIMELIMITED        1

#define        BPRIO_TIMENONCRITICAL        0

#define        BPRIO_DEFAULT                BPRIO_TIMELIMITED

extern        u_int nbuf;                /* The number of buffer headers */

/*

 * Definitions for the buffer free lists.

 */

#define        BQUEUES                4                /* number of free buffer queues */

#define        BQ_LOCKED        0                /* super-blocks &c */

#define        BQ_LRU                1                /* lru, useful buffers */

#define        BQ_AGE                2                /* rubbish */

#define        BQ_EMPTY        3                /* buffer headers with no memory */

struct bqueue {

        TAILQ_HEAD(, buf) bq_queue;

        uint64_t bq_bytes;

        buf_t *bq_marker;

};

extern struct bqueue bufqueues[BQUEUES];

__BEGIN_DECLS

int        allocbuf(buf_t *, int, int);

void        bawrite(buf_t *);

void        bdwrite(buf_t *);

void        biodone(buf_t *);

int        biowait(buf_t *);

int        bread(struct vnode *, daddr_t, int, int, buf_t **);

int        breadn(struct vnode *, daddr_t, int, daddr_t *, int *, int,

               int, buf_t **);

void        brelsel(buf_t *, int);

void        brelse(buf_t *, int);

void        bremfree(buf_t *);

void        bufinit(void);

void        bufinit2(void);

int        bwrite(buf_t *);

buf_t        *getblk(struct vnode *, daddr_t, int, int, int);

buf_t        *geteblk(int);

buf_t        *incore(struct vnode *, daddr_t);

void        minphys(buf_t *);

int        physio(void (*)(buf_t *), buf_t *, dev_t, int,

               void (*)(buf_t *), struct uio *);

void        brelvp(buf_t *);

void        reassignbuf(buf_t *, struct vnode *);

void        bgetvp(struct vnode *, buf_t *);

int        buf_syncwait(void);

u_long        buf_memcalc(void);

int        buf_drain(int);

int        buf_setvalimit(vsize_t);

#if defined(DDB) || defined(DEBUGPRINT)

void        vfs_buf_print(buf_t *, int, void (*)(const char *, ...)

    __printflike(1, 2));

#endif

buf_t        *getiobuf(struct vnode *, bool);

void        putiobuf(buf_t *);

void        buf_init(buf_t *);

void        buf_destroy(buf_t *);

int        bbusy(buf_t *, bool, int, kmutex_t *);

void        nestiobuf_iodone(buf_t *);

void        nestiobuf_setup(buf_t *, buf_t *, int, size_t);

void        nestiobuf_done(buf_t *, int, int);

__END_DECLS

#endif /* _KERNEL */

#endif /* !_SYS_BUF_H_ */