/*      $NetBSD: buf.c,v 1.13 2004/06/20 22:20:18 jmc Exp $     */

/*-
 * SPDX-License-Identifier: BSD-4-Clause
 *
 * Copyright (c) 2001 Wasabi Systems, Inc.
 * All rights reserved.
 *
 * Written by Luke Mewburn for Wasabi Systems, 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 for the NetBSD Project by
 *      Wasabi Systems, Inc.
 * 4. The name of Wasabi Systems, Inc. may not be used to endorse
 *    or promote products derived from this software without specific prior
 *    written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY WASABI SYSTEMS, INC. ``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 WASABI SYSTEMS, INC
 * 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.
 */

#include <sys/param.h>
#include <sys/time.h>

#include <assert.h>
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <util.h>

#include "makefs.h"
#include "buf.h"

static TAILQ_HEAD(buftailhead, m_buf) buftail;

int
bread(struct m_vnode *vp, daddr_t blkno, int size, struct ucred *u1 __unused,
    struct m_buf **bpp)
{
        off_t   offset;
        ssize_t rv;
        fsinfo_t *fs = vp->fs;

        assert (bpp != NULL);

        if (debug & DEBUG_BUF_BREAD)
                printf("%s: blkno %lld size %d\n", __func__, (long long)blkno,
                    size);
        *bpp = getblk(vp, blkno, size, 0, 0, 0);
        offset = (off_t)(*bpp)->b_blkno * fs->sectorsize + fs->offset;
        if (debug & DEBUG_BUF_BREAD)
                printf("%s: blkno %lld offset %lld bcount %ld\n", __func__,
                    (long long)(*bpp)->b_blkno, (long long) offset,
                    (*bpp)->b_bcount);
        if (lseek((*bpp)->b_fs->fd, offset, SEEK_SET) == -1)
                err(1, "%s: lseek %lld (%lld)", __func__,
                    (long long)(*bpp)->b_blkno, (long long)offset);
        rv = read((*bpp)->b_fs->fd, (*bpp)->b_data, (size_t)(*bpp)->b_bcount);
        if (debug & DEBUG_BUF_BREAD)
                printf("%s: read %ld (%lld) returned %d\n", __func__,
                    (*bpp)->b_bcount, (long long)offset, (int)rv);
        if (rv == -1)                           /* read error */
                err(1, "%s: read %ld (%lld) returned %d", __func__,
                    (*bpp)->b_bcount, (long long)offset, (int)rv);
        else if (rv != (*bpp)->b_bcount)        /* short read */
                err(1, "%s: read %ld (%lld) returned %d", __func__,
                    (*bpp)->b_bcount, (long long)offset, (int)rv);
        else
                return (0);
}

void
brelse(struct m_buf *bp)
{

        assert (bp != NULL);
        assert (bp->b_data != NULL);

        if (bp->b_lblkno < 0) {
                /*
                 * XXX  don't remove any buffers with negative logical block
                 *      numbers (lblkno), so that we retain the mapping
                 *      of negative lblkno -> real blkno that ffs_balloc()
                 *      sets up.
                 *
                 *      if we instead released these buffers, and implemented
                 *      ufs_strategy() (and ufs_bmaparray()) and called those
                 *      from bread() and bwrite() to convert the lblkno to
                 *      a real blkno, we'd add a lot more code & complexity
                 *      and reading off disk, for little gain, because this
                 *      simple hack works for our purpose.
                 */
                bp->b_bcount = 0;
                return;
        }

        TAILQ_REMOVE(&buftail, bp, b_tailq);
        free(bp->b_data);
        free(bp);
}

int
bwrite(struct m_buf *bp)
{
        off_t   offset;
        ssize_t rv;
        size_t  bytes;
        int     e;
        fsinfo_t *fs = bp->b_fs;

        assert (bp != NULL);
        offset = (off_t)bp->b_blkno * fs->sectorsize + fs->offset;
        bytes = (size_t)bp->b_bcount;
        if (debug & DEBUG_BUF_BWRITE)
                printf("%s: blkno %lld offset %lld bcount %zu\n", __func__,
                    (long long)bp->b_blkno, (long long) offset, bytes);
        if (lseek(bp->b_fs->fd, offset, SEEK_SET) == -1) {
                brelse(bp);
                return (errno);
        }
        rv = write(bp->b_fs->fd, bp->b_data, bytes);
        e = errno;
        if (debug & DEBUG_BUF_BWRITE)
                printf("%s: write %ld (offset %lld) returned %lld\n", __func__,
                    bp->b_bcount, (long long)offset, (long long)rv);
        brelse(bp);
        if (rv == (ssize_t)bytes)
                return (0);
        if (rv == -1)           /* write error */
                return (e);
        return (EAGAIN);
}

void
bcleanup(void)
{
        struct m_buf *bp;

        /*
         * XXX  this really shouldn't be necessary, but i'm curious to
         *      know why there's still some buffers lying around that
         *      aren't brelse()d
         */

        if (TAILQ_EMPTY(&buftail))
                return;

        printf("%s: unflushed buffers:\n", __func__);
        TAILQ_FOREACH(bp, &buftail, b_tailq) {
                printf("\tlblkno %10lld  blkno %10lld  count %6ld  bufsize %6ld\n",
                    (long long)bp->b_lblkno, (long long)bp->b_blkno,
                    bp->b_bcount, bp->b_bufsize);
        }
        printf("%s: done\n", __func__);
}

struct m_buf *
getblk(struct m_vnode *vp, daddr_t blkno, int size, int u1 __unused,
    int u2 __unused, int u3 __unused)
{
        static int buftailinitted;
        struct m_buf *bp;
        void *n;

        if (debug & DEBUG_BUF_GETBLK)
                printf("%s: blkno %lld size %d\n", __func__, (long long)blkno,
                    size);

        bp = NULL;
        if (!buftailinitted) {
                if (debug & DEBUG_BUF_GETBLK)
                        printf("%s: initialising tailq\n", __func__);
                TAILQ_INIT(&buftail);
                buftailinitted = 1;
        } else {
                TAILQ_FOREACH(bp, &buftail, b_tailq) {
                        if (bp->b_lblkno != blkno)
                                continue;
                        break;
                }
        }
        if (bp == NULL) {
                bp = ecalloc(1, sizeof(*bp));
                bp->b_bufsize = 0;
                bp->b_blkno = bp->b_lblkno = blkno;
                bp->b_fs = vp->fs;
                bp->b_data = NULL;
                TAILQ_INSERT_HEAD(&buftail, bp, b_tailq);
        }
        bp->b_bcount = size;
        if (bp->b_data == NULL || bp->b_bcount > bp->b_bufsize) {
                n = erealloc(bp->b_data, (size_t)size);
                memset(n, 0, (size_t)size);
                bp->b_data = n;
                bp->b_bufsize = size;
        }

        return (bp);
}