store_io_diskd.c

功能强大的代理服务器

/*
 * $Id$
 *
 * DEBUG: section 79    Squid-side DISKD I/O functions.
 * AUTHOR: Duane Wessels
 *
 * SQUID Web Proxy Cache          http://www.squid-cache.org/
 * ----------------------------------------------------------
 *
 *  Squid is the result of efforts by numerous individuals from
 *  the Internet community; see the CONTRIBUTORS file for full
 *  details.   Many organizations have provided support for Squid's
 *  development; see the SPONSORS file for full details.  Squid is
 *  Copyrighted (C) 2001 by the Regents of the University of
 *  California; see the COPYRIGHT file for full details.  Squid
 *  incorporates software developed and/or copyrighted by other
 *  sources; see the CREDITS file for full details.
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *  
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *  
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, write to the Free Software
 *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111, USA.
 *
 */

#include "config.h"
#include "squid.h"

#include <sys/ipc.h>
#include <sys/msg.h>
#include <sys/shm.h>

#include "store_diskd.h"

static int storeDiskdSend(int, SwapDir *, int, storeIOState *, int, off_t, int);
static void storeDiskdIOCallback(storeIOState * sio, int errflag);
static CBDUNL storeDiskdIOFreeEntry;

CBDATA_TYPE(storeIOState);

/* === PUBLIC =========================================================== */

storeIOState *
storeDiskdOpen(SwapDir * SD, StoreEntry * e, STFNCB * file_callback,
    STIOCB * callback, void *callback_data)
{
    sfileno f = e->swap_filen;
    int x;
    storeIOState *sio;
    char *buf;
    diskdstate_t *diskdstate;
    int shm_offset;
    diskdinfo_t *diskdinfo = SD->fsdata;
    debug(79, 3) ("storeDiskdOpen: fileno %08X\n", f);
    /*
     * Fail on open() if there are too many requests queued.
     */
    if (diskdinfo->away > diskdinfo->magic1) {
	debug(79, 3) ("storeDiskdOpen: FAILING, too many requests away\n");
	diskd_stats.open_fail_queue_len++;
	return NULL;
    }
    CBDATA_INIT_TYPE_FREECB(storeIOState, storeDiskdIOFreeEntry);
    sio = cbdataAlloc(storeIOState);
    sio->fsstate = diskdstate = memPoolAlloc(diskd_state_pool);

    sio->swap_filen = f;
    sio->swap_dirn = SD->index;
    sio->mode = O_RDONLY | O_BINARY | O_NOATIME;
    sio->callback = callback;
    sio->callback_data = callback_data;
    sio->e = e;
    cbdataLock(callback_data);

    diskdstate->flags.writing = 0;
    diskdstate->flags.reading = 0;
    diskdstate->flags.close_request = 0;
    diskdstate->id = diskd_stats.sio_id++;

    buf = storeDiskdShmGet(SD, &shm_offset);
    xstrncpy(buf, storeDiskdDirFullPath(SD, f, NULL), SHMBUF_BLKSZ);
    x = storeDiskdSend(_MQD_OPEN,
	SD,
	diskdstate->id,
	sio,
	strlen(buf) + 1,
	O_RDONLY,
	shm_offset);
    if (x < 0) {
	debug(79, 1) ("storeDiskdSend OPEN: %s\n", xstrerror());
	storeDiskdShmPut(SD, shm_offset);
	cbdataUnlock(sio->callback_data);
	cbdataFree(sio);
	return NULL;
    }
    diskd_stats.open.ops++;
    return sio;
}

storeIOState *
storeDiskdCreate(SwapDir * SD, StoreEntry * e, STFNCB * file_callback,
    STIOCB * callback, void *callback_data)
{
    sfileno f;
    int x;
    storeIOState *sio;
    char *buf;
    int shm_offset;
    diskdinfo_t *diskdinfo = SD->fsdata;
    diskdstate_t *diskdstate;
    /*
     * Fail on open() if there are too many requests queued.
     */
    if (diskdinfo->away > diskdinfo->magic1) {
	diskd_stats.open_fail_queue_len++;
	return NULL;
    }
    /* Allocate a number */
    f = storeDiskdDirMapBitAllocate(SD);
    debug(79, 3) ("storeDiskdCreate: fileno %08X\n", f);

    CBDATA_INIT_TYPE_FREECB(storeIOState, storeDiskdIOFreeEntry);
    sio = cbdataAlloc(storeIOState);
    sio->fsstate = diskdstate = memPoolAlloc(diskd_state_pool);

    sio->swap_filen = f;
    sio->swap_dirn = SD->index;
    sio->mode = O_WRONLY | O_CREAT | O_TRUNC;
    sio->callback = callback;
    sio->callback_data = callback_data;
    sio->e = e;
    cbdataLock(callback_data);

    diskdstate->flags.writing = 0;
    diskdstate->flags.reading = 0;
    diskdstate->flags.close_request = 0;
    diskdstate->id = diskd_stats.sio_id++;

    buf = storeDiskdShmGet(SD, &shm_offset);
    xstrncpy(buf, storeDiskdDirFullPath(SD, f, NULL), SHMBUF_BLKSZ);
    x = storeDiskdSend(_MQD_OPEN,
	SD,
	diskdstate->id,
	sio,
	strlen(buf) + 1,
	sio->mode,
	shm_offset);
    if (x < 0) {
	debug(79, 1) ("storeDiskdSend OPEN: %s\n", xstrerror());
	storeDiskdShmPut(SD, shm_offset);
	cbdataUnlock(sio->callback_data);
	cbdataFree(sio);
	return NULL;
    }
    storeDiskdDirReplAdd(SD, e);
    diskd_stats.create.ops++;
    return sio;
}


void
storeDiskdClose(SwapDir * SD, storeIOState * sio)
{
    int x;
    diskdstate_t *diskdstate = sio->fsstate;
    debug(79, 3) ("storeDiskdClose: dirno %d, fileno %08X\n", SD->index,
	sio->swap_filen);
    diskdstate->flags.close_request = 1;
    x = storeDiskdSend(_MQD_CLOSE,
	SD,
	diskdstate->id,
	sio,
	0,
	0,
	-1);
    if (x < 0) {
	debug(79, 1) ("storeDiskdSend CLOSE: %s\n", xstrerror());
	storeDiskdIOCallback(sio, DISK_ERROR);
    }
    diskd_stats.close.ops++;
}

void
storeDiskdRead(SwapDir * SD, storeIOState * sio, char *buf, size_t size, squid_off_t offset, STRCB * callback, void *callback_data)
{
    int x;
    int shm_offset;
    char *rbuf;
    diskdstate_t *diskdstate = sio->fsstate;
    debug(79, 3) ("storeDiskdRead: dirno %d, fileno %08X\n", sio->swap_dirn, sio->swap_filen);
    if (diskdstate->flags.close_request) {
	debug(79, 2) ("storeDiskRead: closing, so ignore!\n");
	return;
    }
    if (!cbdataValid(sio))
	return;
    if (diskdstate->flags.reading) {
	debug(79, 1) ("storeDiskdRead: already reading!\n");
	return;
    }
    assert(sio->read.callback == NULL);
    assert(sio->read.callback_data == NULL);
    sio->read.callback = callback;
    sio->read.callback_data = callback_data;
    diskdstate->read_buf = buf;	/* the one passed from above */
    cbdataLock(sio->read.callback_data);
    sio->offset = offset;
    diskdstate->flags.reading = 1;
    rbuf = storeDiskdShmGet(SD, &shm_offset);
    assert(rbuf);
    x = storeDiskdSend(_MQD_READ,
	SD,
	diskdstate->id,
	sio,
	size,
	(off_t) offset,
	shm_offset);
    if (x < 0) {
	debug(79, 1) ("storeDiskdSend READ: %s\n", xstrerror());
	storeDiskdShmPut(SD, shm_offset);
	storeDiskdIOCallback(sio, DISK_ERROR);
    }
    diskd_stats.read.ops++;
}

void
storeDiskdWrite(SwapDir * SD, storeIOState * sio, char *buf, size_t size, squid_off_t offset, FREE * free_func)
{
    int x;
    char *sbuf;
    int shm_offset;
    diskdstate_t *diskdstate = sio->fsstate;
    debug(79, 3) ("storeDiskdWrite: dirno %d, fileno %08X\n", SD->index, sio->swap_filen);
    assert(!diskdstate->flags.close_request);
    if (diskdstate->flags.close_request) {
	debug(79, 2) ("storeDiskWrite: closing, so ignore!\n");
	free_func(buf);
	return;
    }
    if (!cbdataValid(sio)) {
	free_func(buf);
	return;
    }
    diskdstate->flags.writing = 1;
    sbuf = storeDiskdShmGet(SD, &shm_offset);
    xmemcpy(sbuf, buf, size);
    if (free_func)
	free_func(buf);
    x = storeDiskdSend(_MQD_WRITE,
	SD,
	diskdstate->id,
	sio,
	size,
	(off_t) offset,
	shm_offset);
    if (x < 0) {
	debug(79, 1) ("storeDiskdSend WRITE: %s\n", xstrerror());
	storeDiskdShmPut(SD, shm_offset);
	storeDiskdIOCallback(sio, DISK_ERROR);
    }
    diskd_stats.write.ops++;
}

void
storeDiskdUnlink(SwapDir * SD, StoreEntry * e)
{
    int x;
    int shm_offset;
    char *buf;
    diskdinfo_t *diskdinfo = SD->fsdata;

    debug(79, 3) ("storeDiskdUnlink: dirno %d, fileno %08X\n", SD->index,
	e->swap_filen);
    storeDiskdDirReplRemove(e);
    storeDiskdDirMapBitReset(SD, e->swap_filen);