Bootstrapped

[thirdparty/squid.git] / src / fs / coss / store_dir_coss.cc

/*
 * $Id: store_dir_coss.cc,v 1.40 2002/10/15 08:03:33 robertc Exp $
 *
 * DEBUG: section 47    Store COSS Directory Routines
 * AUTHOR: Eric Stern
 *
 * 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 "squid.h"
#include "Store.h"
#include <aio.h>

#include "async_io.h"
#include "store_coss.h"

#define STORE_META_BUFSZ 4096

int n_coss_dirs = 0;
/* static int last_coss_pick_index = -1; */
int coss_initialised = 0;
MemPool *coss_state_pool = NULL;
MemPool *coss_index_pool = NULL;

typedef struct _RebuildState RebuildState;
struct _RebuildState {
    SwapDir *sd;
    int n_read;
    FILE *log;
    int speed;
    struct {
	unsigned int clean:1;
    } flags;
    struct _store_rebuild_data counts;
};

static char *storeCossDirSwapLogFile(SwapDir *, const char *);
static EVH storeCossRebuildFromSwapLog;
static StoreEntry *storeCossAddDiskRestore(SwapDir * SD, const cache_key * key,
    int file_number,
    size_t swap_file_sz,
    time_t expires,
    time_t timestamp,
    time_t lastref,
    time_t lastmod,
    u_int32_t refcount,
    u_int16_t flags,
    int clean);
static void storeCossDirRebuild(SwapDir * sd);
static void storeCossDirCloseTmpSwapLog(SwapDir * sd);
static FILE *storeCossDirOpenTmpSwapLog(SwapDir *, int *, int *);
static STLOGOPEN storeCossDirOpenSwapLog;
static STINIT storeCossDirInit;
static STLOGCLEANSTART storeCossDirWriteCleanStart;
static STLOGCLEANNEXTENTRY storeCossDirCleanLogNextEntry;
static STLOGCLEANWRITE storeCossDirWriteCleanEntry;
static STLOGCLEANDONE storeCossDirWriteCleanDone;
static STLOGCLOSE storeCossDirCloseSwapLog;
static STLOGWRITE storeCossDirSwapLog;
static STNEWFS storeCossDirNewfs;
static STCHECKOBJ storeCossDirCheckObj;
static STFREE storeCossDirShutdown;
static STFSPARSE storeCossDirParse;
static STFSRECONFIGURE storeCossDirReconfigure;
static STDUMP storeCossDirDump;
static STCALLBACK storeCossDirCallback;

/* The "only" externally visible function */
STSETUP storeFsSetup_coss;

static char *
storeCossDirSwapLogFile(SwapDir * sd, const char *ext)
{
    LOCAL_ARRAY(char, path, SQUID_MAXPATHLEN);
    LOCAL_ARRAY(char, pathtmp, SQUID_MAXPATHLEN);
    LOCAL_ARRAY(char, digit, 32);
    char *pathtmp2;
    if (Config.Log.swap) {
	xstrncpy(pathtmp, sd->path, SQUID_MAXPATHLEN - 64);
	pathtmp2 = pathtmp;
	while ((pathtmp2 = strchr(pathtmp2, '/')) != NULL)
	    *pathtmp2 = '.';
	while (strlen(pathtmp) && pathtmp[strlen(pathtmp) - 1] == '.')
	    pathtmp[strlen(pathtmp) - 1] = '\0';
	for (pathtmp2 = pathtmp; *pathtmp2 == '.'; pathtmp2++);
	snprintf(path, SQUID_MAXPATHLEN - 64, Config.Log.swap, pathtmp2);
	if (strncmp(path, Config.Log.swap, SQUID_MAXPATHLEN - 64) == 0) {
	    strcat(path, ".");
	    snprintf(digit, 32, "%02d", sd->index);
	    strncat(path, digit, 3);
	}
    } else {
	xstrncpy(path, sd->path, SQUID_MAXPATHLEN - 64);
	strcat(path, "/swap.state");
    }
    if (ext)
	strncat(path, ext, 16);
    return path;
}

static void
storeCossDirOpenSwapLog(SwapDir * sd)
{
    CossInfo *cs = (CossInfo *) sd->fsdata;
    char *path;
    int fd;
    path = storeCossDirSwapLogFile(sd, NULL);
    fd = file_open(path, O_WRONLY | O_CREAT | O_BINARY);
    if (fd < 0) {
	debug(47, 1) ("%s: %s\n", path, xstrerror());
	fatal("storeCossDirOpenSwapLog: Failed to open swap log.");
    }
    debug(47, 3) ("Cache COSS Dir #%d log opened on FD %d\n", sd->index, fd);
    cs->swaplog_fd = fd;
}

static void
storeCossDirCloseSwapLog(SwapDir * sd)
{
    CossInfo *cs = (CossInfo *) sd->fsdata;
    if (cs->swaplog_fd < 0)	/* not open */
	return;
    file_close(cs->swaplog_fd);
    debug(47, 3) ("Cache COSS Dir #%d log closed on FD %d\n",
	sd->index, cs->swaplog_fd);
    cs->swaplog_fd = -1;
}

static void
storeCossDirInit(SwapDir * sd)
{
    CossInfo *cs = (CossInfo *) sd->fsdata;
    a_file_setupqueue(&cs->aq);
    storeCossDirOpenSwapLog(sd);
    storeCossDirRebuild(sd);
    cs->fd = file_open(sd->path, O_RDWR | O_CREAT);
    if (cs->fd < 0) {
	debug(47, 1) ("%s: %s\n", sd->path, xstrerror());
	fatal("storeCossDirInit: Failed to open a COSS directory.");
    }
    n_coss_dirs++;
    (void) storeDirGetBlkSize(sd->path, &sd->fs.blksize);
}

void
storeCossRemove(SwapDir * sd, StoreEntry * e)
{
    CossInfo *cs = (CossInfo *) sd->fsdata;
    CossIndexNode *coss_node = (CossIndexNode *)e->repl.data;
    e->repl.data = NULL;
    dlinkDelete(&coss_node->node, &cs->index);
    memPoolFree(coss_index_pool, coss_node);
    cs->count -= 1;
}

void
storeCossAdd(SwapDir * sd, StoreEntry * e)
{
    CossInfo *cs = (CossInfo *) sd->fsdata;
    CossIndexNode *coss_node = (CossIndexNode *)memPoolAlloc(coss_index_pool);
    assert(!e->repl.data);
    e->repl.data = coss_node;
    dlinkAdd(e, &coss_node->node, &cs->index);
    cs->count += 1;
}

static void
storeCossRebuildComplete(void *data)
{
    RebuildState *rb = (RebuildState *)data;
    SwapDir *sd = rb->sd;
    storeCossStartMembuf(sd);
    store_dirs_rebuilding--;
    storeCossDirCloseTmpSwapLog(rb->sd);
    storeRebuildComplete(&rb->counts);
    cbdataFree(rb);
}

static void
storeCossRebuildFromSwapLog(void *data)
{
    RebuildState *rb = (RebuildState *)data;
    StoreEntry *e = NULL;
    storeSwapLogData s;
    size_t ss = sizeof(storeSwapLogData);
    int count;
    double x;
    assert(rb != NULL);
    /* load a number of objects per invocation */
    for (count = 0; count < rb->speed; count++) {
	if (fread(&s, ss, 1, rb->log) != 1) {
	    debug(47, 1) ("Done reading %s swaplog (%d entries)\n",
		rb->sd->path, rb->n_read);
	    fclose(rb->log);
	    rb->log = NULL;
	    storeCossRebuildComplete(rb);
	    return;
	}
	rb->n_read++;
	if (s.op <= SWAP_LOG_NOP)
	    continue;
	if (s.op >= SWAP_LOG_MAX)
	    continue;
	debug(47, 3) ("storeCossRebuildFromSwapLog: %s %s %08X\n",
	    swap_log_op_str[(int) s.op],
	    storeKeyText(s.key),
	    s.swap_filen);
	if (s.op == SWAP_LOG_ADD) {
	    (void) 0;
	} else if (s.op == SWAP_LOG_DEL) {
	    if ((e = storeGet(s.key)) != NULL) {
		/*
		 * Make sure we don't unlink the file, it might be
		 * in use by a subsequent entry.  Also note that
		 * we don't have to subtract from store_swap_size
		 * because adding to store_swap_size happens in
		 * the cleanup procedure.
		 */
		storeExpireNow(e);
		storeReleaseRequest(e);
		if (e->swap_filen > -1) {
		    e->swap_filen = -1;
		}
		storeRelease(e);
		/* Fake an unlink here, this is a bad hack :( */
		storeCossRemove(rb->sd, e);
		rb->counts.objcount--;
		rb->counts.cancelcount++;
	    }
	    continue;
	} else {
	    x = log(++rb->counts.bad_log_op) / log(10.0);
	    if (0.0 == x - (double) (int) x)
		debug(47, 1) ("WARNING: %d invalid swap log entries found\n",
		    rb->counts.bad_log_op);
	    rb->counts.invalid++;
	    continue;
	}
	if ((++rb->counts.scancount & 0xFFF) == 0) {
	    struct stat sb;
	    if (0 == fstat(fileno(rb->log), &sb))
		storeRebuildProgress(rb->sd->index,
		    (int) sb.st_size / ss, rb->n_read);
	}
	if (EBIT_TEST(s.flags, KEY_PRIVATE)) {
	    rb->counts.badflags++;
	    continue;
	}
	e = storeGet(s.key);
	if (e) {
	    /* key already exists, current entry is newer */
	    /* keep old, ignore new */
	    rb->counts.dupcount++;
	    continue;
	}
	/* update store_swap_size */
	rb->counts.objcount++;
	e = storeCossAddDiskRestore(rb->sd, s.key,
	    s.swap_filen,
	    s.swap_file_sz,
	    s.expires,
	    s.timestamp,
	    s.lastref,
	    s.lastmod,
	    s.refcount,
	    s.flags,
	    (int) rb->flags.clean);
	storeDirSwapLog(e, SWAP_LOG_ADD);
    }
    eventAdd("storeCossRebuild", storeCossRebuildFromSwapLog, rb, 0.0, 1);
}

/* Add a new object to the cache with empty memory copy and pointer to disk
 * use to rebuild store from disk. */
static StoreEntry *
storeCossAddDiskRestore(SwapDir * SD, const cache_key * key,
    int file_number,
    size_t swap_file_sz,
    time_t expires,
    time_t timestamp,
    time_t lastref,
    time_t lastmod,
    u_int32_t refcount,
    u_int16_t flags,
    int clean)
{
    StoreEntry *e = NULL;
    debug(47, 5) ("storeCossAddDiskRestore: %s, fileno=%08X\n", storeKeyText(key), file_number);
    /* if you call this you'd better be sure file_number is not 
     * already in use! */
    e = new_StoreEntry(STORE_ENTRY_WITHOUT_MEMOBJ, NULL, NULL);
    e->store_status = STORE_OK;
    e->swap_dirn = SD->index;
    storeSetMemStatus(e, NOT_IN_MEMORY);
    e->swap_status = SWAPOUT_DONE;
    e->swap_filen = file_number;
    e->swap_file_sz = swap_file_sz;
    e->lock_count = 0;
    e->lastref = lastref;
    e->timestamp = timestamp;
    e->expires = expires;
    e->lastmod = lastmod;
    e->refcount = refcount;
    e->flags = flags;
    EBIT_SET(e->flags, ENTRY_CACHABLE);
    EBIT_CLR(e->flags, RELEASE_REQUEST);
    EBIT_CLR(e->flags, KEY_PRIVATE);
    e->ping_status = PING_NONE;
    EBIT_CLR(e->flags, ENTRY_VALIDATED);
    storeHashInsert(e, key);	/* do it after we clear KEY_PRIVATE */
    storeCossAdd(SD, e);
    e->swap_filen = storeCossAllocate(SD, e, COSS_ALLOC_NOTIFY);
    return e;
}

CBDATA_TYPE(RebuildState);
static void
storeCossDirRebuild(SwapDir * sd)
{
    RebuildState *rb;
    int clean = 0;
    int zero = 0;
    FILE *fp;
    EVH *func = NULL;
    CBDATA_INIT_TYPE(RebuildState);
    rb = cbdataAlloc(RebuildState);
    rb->sd = sd;
    rb->speed = opt_foreground_rebuild ? 1 << 30 : 50;
    func = storeCossRebuildFromSwapLog;
    rb->flags.clean = (unsigned int) clean;
    /*
     * If the swap.state file exists in the cache_dir, then
     * we'll use storeCossRebuildFromSwapLog().
     */
    fp = storeCossDirOpenTmpSwapLog(sd, &clean, &zero);
    debug(47, 1) ("Rebuilding COSS storage in %s (%s)\n",
	sd->path, clean ? "CLEAN" : "DIRTY");
    rb->log = fp;
    store_dirs_rebuilding++;
    if (!clean || fp == NULL) {
	/* COSS cannot yet rebuild from a dirty state. If the log
	 * is dirty then the COSS contents is thrown away.
	 * Why? I guess it is because some contents will be lost,
	 * and COSS cannot verify this..
	 */
	if (fp != NULL)
	    fclose(fp);
	/*
	 * XXX Make sure we don't trigger an assertion if this is the first
	 * storedir, since if we are, this call will cause storeRebuildComplete
	 * to prematurely complete the rebuild process, and then some other
	 * storedir will try to rebuild and eventually die.
	 */
	eventAdd("storeCossRebuildComplete", storeCossRebuildComplete, rb, 0.0, 0);
	return;
    }
    eventAdd("storeCossRebuild", func, rb, 0.0, 1);
}

static void
storeCossDirCloseTmpSwapLog(SwapDir * sd)
{
    CossInfo *cs = (CossInfo *) sd->fsdata;
    char *swaplog_path = xstrdup(storeCossDirSwapLogFile(sd, NULL));
    char *new_path = xstrdup(storeCossDirSwapLogFile(sd, ".new"));
    int fd;
    file_close(cs->swaplog_fd);
#if defined (_SQUID_OS2_) || defined (_SQUID_CYGWIN_)
    if (unlink(swaplog_path) < 0) {
	debug(50, 0) ("%s: %s\n", swaplog_path, xstrerror());
	fatal("storeCossDirCloseTmpSwapLog: unlink failed");
    }
#endif
    if (xrename(new_path, swaplog_path) < 0) {
	fatal("storeCossDirCloseTmpSwapLog: rename failed");
    }
    fd = file_open(swaplog_path, O_WRONLY | O_CREAT | O_BINARY);
    if (fd < 0) {
	debug(50, 1) ("%s: %s\n", swaplog_path, xstrerror());
	fatal("storeCossDirCloseTmpSwapLog: Failed to open swap log.");
    }
    safe_free(swaplog_path);
    safe_free(new_path);
    cs->swaplog_fd = fd;
    debug(47, 3) ("Cache COSS Dir #%d log opened on FD %d\n", sd->index, fd);
}

static FILE *
storeCossDirOpenTmpSwapLog(SwapDir * sd, int *clean_flag, int *zero_flag)
{
    CossInfo *cs = (CossInfo *) sd->fsdata;
    char *swaplog_path = xstrdup(storeCossDirSwapLogFile(sd, NULL));
    char *clean_path = xstrdup(storeCossDirSwapLogFile(sd, ".last-clean"));
    char *new_path = xstrdup(storeCossDirSwapLogFile(sd, ".new"));
    struct stat log_sb;
    struct stat clean_sb;
    FILE *fp;
    int fd;
    if (stat(swaplog_path, &log_sb) < 0) {
	debug(50, 1) ("Cache COSS Dir #%d: No log file\n", sd->index);
	safe_free(swaplog_path);
	safe_free(clean_path);
	safe_free(new_path);
	return NULL;
    }
    *zero_flag = log_sb.st_size == 0 ? 1 : 0;
    /* close the existing write-only FD */
    if (cs->swaplog_fd >= 0)
	file_close(cs->swaplog_fd);
    /* open a write-only FD for the new log */
    fd = file_open(new_path, O_WRONLY | O_CREAT | O_TRUNC | O_BINARY);
    if (fd < 0) {
	debug(50, 1) ("%s: %s\n", new_path, xstrerror());
	fatal("storeDirOpenTmpSwapLog: Failed to open swap log.");
    }
    cs->swaplog_fd = fd;
    /* open a read-only stream of the old log */
    fp = fopen(swaplog_path, "rb");
    if (fp == NULL) {
	debug(50, 0) ("%s: %s\n", swaplog_path, xstrerror());
	fatal("Failed to open swap log for reading");
    }
    memset(&clean_sb, '\0', sizeof(struct stat));
    if (stat(clean_path, &clean_sb) < 0)
	*clean_flag = 0;
    else if (clean_sb.st_mtime < log_sb.st_mtime)
	*clean_flag = 0;
    else
	*clean_flag = 1;
    safeunlink(clean_path, 1);
    safe_free(swaplog_path);
    safe_free(clean_path);
    safe_free(new_path);
    return fp;
}

struct _clean_state {
    char *cur;
    char *newLog;
    char *cln;
    char *outbuf;
    off_t outbuf_offset;
    int fd;
    dlink_node *current;
};

#define CLEAN_BUF_SZ 16384
/*
 * Begin the process to write clean cache state.  For COSS this means
 * opening some log files and allocating write buffers.  Return 0 if
 * we succeed, and assign the 'func' and 'data' return pointers.
 */
static int
storeCossDirWriteCleanStart(SwapDir * sd)
{
    CossInfo *cs = (CossInfo *) sd->fsdata;
    struct _clean_state *state = (struct _clean_state *)xcalloc(1, sizeof(*state));
#if HAVE_FCHMOD
    struct stat sb;
#endif
    state->newLog = xstrdup(storeCossDirSwapLogFile(sd, ".clean"));
    state->fd = file_open(state->newLog, O_WRONLY | O_CREAT | O_TRUNC | O_BINARY);
    if (state->fd < 0) {
	xfree(state->newLog);
	xfree(state);
	return -1;
    }
    sd->log.clean.write = NULL;
    sd->log.clean.state = NULL;
    state->cur = xstrdup(storeCossDirSwapLogFile(sd, NULL));
    state->cln = xstrdup(storeCossDirSwapLogFile(sd, ".last-clean"));
    state->outbuf = (char *)xcalloc(CLEAN_BUF_SZ, 1);
    state->outbuf_offset = 0;
    unlink(state->cln);
    state->current = cs->index.tail;
    debug(50, 3) ("storeCOssDirWriteCleanLogs: opened %s, FD %d\n",
	state->newLog, state->fd);
#if HAVE_FCHMOD
    if (stat(state->cur, &sb) == 0)
	fchmod(state->fd, sb.st_mode);
#endif
    sd->log.clean.write = storeCossDirWriteCleanEntry;
    sd->log.clean.state = state;

    return 0;
}

static const StoreEntry *
storeCossDirCleanLogNextEntry(SwapDir * sd)
{
    struct _clean_state *state = (struct _clean_state *)sd->log.clean.state;
    const StoreEntry *entry;
    if (!state)
	return NULL;
    if (!state->current)
	return NULL;
    entry = (const StoreEntry *) state->current->data;
    state->current = state->current->prev;
    return entry;
}

/*
 * "write" an entry to the clean log file.
 */
static void
storeCossDirWriteCleanEntry(SwapDir * sd, const StoreEntry * e)
{
    storeSwapLogData s;
    static size_t ss = sizeof(storeSwapLogData);
    struct _clean_state *state = (struct _clean_state *)sd->log.clean.state;
    memset(&s, '\0', ss);
    s.op = (char) SWAP_LOG_ADD;
    s.swap_filen = e->swap_filen;
    s.timestamp = e->timestamp;
    s.lastref = e->lastref;
    s.expires = e->expires;
    s.lastmod = e->lastmod;
    s.swap_file_sz = e->swap_file_sz;
    s.refcount = e->refcount;
    s.flags = e->flags;
    xmemcpy(&s.key, e->key, MD5_DIGEST_CHARS);
    xmemcpy(state->outbuf + state->outbuf_offset, &s, ss);
    state->outbuf_offset += ss;
    /* buffered write */
    if (state->outbuf_offset + ss > CLEAN_BUF_SZ) {
	if (FD_WRITE_METHOD(state->fd, state->outbuf, state->outbuf_offset) < 0) {
	    debug(50, 0) ("storeCossDirWriteCleanLogs: %s: write: %s\n",
		state->newLog, xstrerror());
	    debug(50, 0) ("storeCossDirWriteCleanLogs: Current swap logfile not replaced.\n");
	    file_close(state->fd);
	    state->fd = -1;
	    unlink(state->newLog);
	    safe_free(state);
	    sd->log.clean.state = NULL;
	    sd->log.clean.write = NULL;
	    return;
	}
	state->outbuf_offset = 0;
    }
}

static void
storeCossDirWriteCleanDone(SwapDir * sd)
{
    int fd;
    struct _clean_state *state = (struct _clean_state *)sd->log.clean.state;
    if (NULL == state)
	return;
    if (state->fd < 0)
	return;
    if (FD_WRITE_METHOD(state->fd, state->outbuf, state->outbuf_offset) < 0) {
	debug(50, 0) ("storeCossDirWriteCleanLogs: %s: write: %s\n",
	    state->newLog, xstrerror());
	debug(50, 0) ("storeCossDirWriteCleanLogs: Current swap logfile "
	    "not replaced.\n");
	file_close(state->fd);
	state->fd = -1;
	unlink(state->newLog);
    }
    safe_free(state->outbuf);
    /*
     * You can't rename open files on Microsoft "operating systems"
     * so we have to close before renaming.
     */
    storeCossDirCloseSwapLog(sd);
    /* save the fd value for a later test */
    fd = state->fd;
    /* rename */
    if (state->fd >= 0) {
#if defined(_SQUID_OS2_) || defined (_SQUID_CYGWIN_)
	file_close(state->fd);
	state->fd = -1;
	if (unlink(state->cur) < 0)
	    debug(50, 0) ("storeCossDirWriteCleanLogs: unlinkd failed: %s, %s\n",
		xstrerror(), state->cur);
#endif
	xrename(state->newLog, state->cur);
    }
    /* touch a timestamp file if we're not still validating */
    if (store_dirs_rebuilding)
	(void) 0;
    else if (fd < 0)
	(void) 0;
    else
	file_close(file_open(state->cln, O_WRONLY | O_CREAT | O_TRUNC | O_BINARY));
    /* close */
    safe_free(state->cur);
    safe_free(state->newLog);
    safe_free(state->cln);
    if (state->fd >= 0)
	file_close(state->fd);
    state->fd = -1;
    safe_free(state);
    sd->log.clean.state = NULL;
    sd->log.clean.write = NULL;
}

static void
storeSwapLogDataFree(void *s)
{
    memFree(s, MEM_SWAP_LOG_DATA);
}

static void
storeCossDirSwapLog(const SwapDir * sd, const StoreEntry * e, int op)
{
    CossInfo *cs = (CossInfo *) sd->fsdata;
    storeSwapLogData *s = (storeSwapLogData *)memAllocate(MEM_SWAP_LOG_DATA);
    s->op = (char) op;
    s->swap_filen = e->swap_filen;
    s->timestamp = e->timestamp;
    s->lastref = e->lastref;
    s->expires = e->expires;
    s->lastmod = e->lastmod;
    s->swap_file_sz = e->swap_file_sz;
    s->refcount = e->refcount;
    s->flags = e->flags;
    xmemcpy(s->key, e->key, MD5_DIGEST_CHARS);
    file_write(cs->swaplog_fd,
	-1,
	s,
	sizeof(storeSwapLogData),
	NULL,
	NULL,
	(FREE *) storeSwapLogDataFree);
}

static void
storeCossDirNewfs(SwapDir * sd)
{
    debug(47, 3) ("Creating swap space in %s\n", sd->path);
}

/* we are shutting down, flush all membufs to disk */
static void
storeCossDirShutdown(SwapDir * SD)
{
    CossInfo *cs = (CossInfo *) SD->fsdata;

    storeCossSync(SD);		/* This'll call a_file_syncqueue() */
    a_file_closequeue(&cs->aq);
    file_close(cs->fd);
    cs->fd = -1;

    if (cs->swaplog_fd > -1) {
	file_close(cs->swaplog_fd);
	cs->swaplog_fd = -1;
    }
    n_coss_dirs--;
}

/*
 * storeCossDirCheckObj
 *
 * This routine is called by storeDirSelectSwapDir to see if the given
 * object is able to be stored on this filesystem. COSS filesystems will
 * not store everything. We don't check for maxobjsize here since its
 * done by the upper layers.
 */
int
storeCossDirCheckObj(SwapDir * SD, const StoreEntry * e)
{
    CossInfo *cs = (CossInfo *) SD->fsdata;
    int loadav;

    /* Check if the object is a special object, we can't cache these */
    if (EBIT_TEST(e->flags, ENTRY_SPECIAL))
	return -1;

    /* Otherwise, we're ok */
    /* Return load, cs->aq.aq_numpending out of MAX_ASYNCOP */
    loadav = cs->aq.aq_numpending * 1000 / MAX_ASYNCOP;
    return loadav;
}


/*
 * storeCossDirCallback - do the IO completions
 */
static int
storeCossDirCallback(SwapDir * SD)
{
    CossInfo *cs = (CossInfo *) SD->fsdata;

    return a_file_callback(&cs->aq);
}

/* ========== LOCAL FUNCTIONS ABOVE, GLOBAL FUNCTIONS BELOW ========== */

static void
storeCossDirStats(SwapDir * SD, StoreEntry * sentry)
{
    CossInfo *cs = (CossInfo *) SD->fsdata;

    storeAppendPrintf(sentry, "\n");
    storeAppendPrintf(sentry, "Maximum Size: %d KB\n", SD->max_size);
    storeAppendPrintf(sentry, "Current Size: %d KB\n", SD->cur_size);
    storeAppendPrintf(sentry, "Percent Used: %0.2f%%\n",
	100.0 * SD->cur_size / SD->max_size);
    storeAppendPrintf(sentry, "Number of object collisions: %d\n", (int) cs->numcollisions);
#if 0
    /* is this applicable? I Hope not .. */
    storeAppendPrintf(sentry, "Filemap bits in use: %d of %d (%d%%)\n",
	SD->map->n_files_in_map, SD->map->max_n_files,
	percent(SD->map->n_files_in_map, SD->map->max_n_files));
#endif
    storeAppendPrintf(sentry, "Pending operations: %d out of %d\n", cs->aq.aq_numpending, MAX_ASYNCOP);
    storeAppendPrintf(sentry, "Flags:");
    if (SD->flags.selected)
	storeAppendPrintf(sentry, " SELECTED");
    if (SD->flags.read_only)
	storeAppendPrintf(sentry, " READ-ONLY");
    storeAppendPrintf(sentry, "\n");
}

static void
storeCossDirParse(SwapDir * sd, int index, char *path)
{
    unsigned int i;
    unsigned int size;
    CossInfo *cs;

    i = GetInteger();
    size = i << 10;		/* Mbytes to Kbytes */
    if (size <= 0)
	fatal("storeCossDirParse: invalid size value");

    cs = (CossInfo *)xmalloc(sizeof(CossInfo));
    if (cs == NULL)
	fatal("storeCossDirParse: couldn't xmalloc() CossInfo!\n");

    sd->index = index;
    sd->path = xstrdup(path);
    sd->max_size = size;
    sd->fsdata = cs;

    cs->fd = -1;
    cs->swaplog_fd = -1;

    sd->init = storeCossDirInit;
    sd->newfs = storeCossDirNewfs;
    sd->dump = storeCossDirDump;
    sd->freefs = storeCossDirShutdown;
    sd->dblcheck = NULL;
    sd->statfs = storeCossDirStats;
    sd->maintainfs = NULL;
    sd->checkobj = storeCossDirCheckObj;
    sd->refobj = NULL;		/* LRU is done in storeCossRead */
    sd->unrefobj = NULL;
    sd->callback = storeCossDirCallback;
    sd->sync = storeCossSync;

    sd->obj.create = storeCossCreate;
    sd->obj.open = storeCossOpen;
    sd->obj.close = storeCossClose;
    sd->obj.read = storeCossRead;
    sd->obj.write = storeCossWrite;
    sd->obj.unlink = storeCossUnlink;

    sd->log.open = storeCossDirOpenSwapLog;
    sd->log.close = storeCossDirCloseSwapLog;
    sd->log.write = storeCossDirSwapLog;
    sd->log.clean.start = storeCossDirWriteCleanStart;
    sd->log.clean.write = storeCossDirWriteCleanEntry;
    sd->log.clean.nextentry = storeCossDirCleanLogNextEntry;
    sd->log.clean.done = storeCossDirWriteCleanDone;

    cs->current_offset = 0;
    cs->fd = -1;
    cs->swaplog_fd = -1;
    cs->numcollisions = 0;
    cs->membufs.head = cs->membufs.tail = NULL;		/* set when the rebuild completes */
    cs->current_membuf = NULL;
    cs->index.head = NULL;
    cs->index.tail = NULL;

    parse_cachedir_options(sd, NULL, 0);
    /* Enforce maxobjsize being set to something */
    if (sd->max_objsize == -1)
	fatal("COSS requires max-size to be set to something other than -1!\n");
}


static void
storeCossDirReconfigure(SwapDir * sd, int index, char *path)
{
    unsigned int i;
    unsigned int size;

    i = GetInteger();
    size = i << 10;		/* Mbytes to Kbytes */
    if (size <= 0)
	fatal("storeCossDirParse: invalid size value");

    if (size == (size_t)sd->max_size)
	debug(3, 1) ("Cache COSS dir '%s' size remains unchanged at %d KB\n", path, size);
    else {
	debug(3, 1) ("Cache COSS dir '%s' size changed to %d KB\n", path, size);
	sd->max_size = size;
    }
    parse_cachedir_options(sd, NULL, 1);
    /* Enforce maxobjsize being set to something */
    if (sd->max_objsize == -1)
	fatal("COSS requires max-size to be set to something other than -1!\n");
}

void
storeCossDirDump(StoreEntry * entry, SwapDir * s)
{
    storeAppendPrintf(entry, " %d",
	s->max_size >> 20);
    dump_cachedir_options(entry, NULL, s);
}

#if OLD_UNUSED_CODE
SwapDir *
storeCossDirPick(void)
{
    int i, choosenext = 0;
    SwapDir *SD;

    if (n_coss_dirs == 0)
	return NULL;
    for (i = 0; i < Config.cacheSwap.n_configured; i++) {
	SD = &Config.cacheSwap.swapDirs[i];
	if (SD->type == SWAPDIR_COSS) {
	    if ((last_coss_pick_index == -1) || (n_coss_dirs == 1)) {
		last_coss_pick_index = i;
		return SD;
	    } else if (choosenext) {
		last_coss_pick_index = i;
		return SD;
	    } else if (last_coss_pick_index == i) {
		choosenext = 1;
	    }
	}
    }
    for (i = 0; i < Config.cacheSwap.n_configured; i++) {
	SD = &Config.cacheSwap.swapDirs[i];
	if (SD->type == SWAPDIR_COSS) {
	    if ((last_coss_pick_index == -1) || (n_coss_dirs == 1)) {
		last_coss_pick_index = i;
		return SD;
	    } else if (choosenext) {
		last_coss_pick_index = i;
		return SD;
	    } else if (last_coss_pick_index == i) {
		choosenext = 1;
	    }
	}
    }
    return NULL;
}
#endif

/*
 * initial setup/done code
 */
static void
storeCossDirDone(void)
{
    memPoolDestroy(&coss_state_pool);
/*  memPoolDestroy(&coss_index_pool);  XXX Should be here? */
    coss_initialised = 0;
}

void
storeFsSetup_coss(storefs_entry_t * storefs)
{
    assert(!coss_initialised);

    storefs->parsefunc = storeCossDirParse;
    storefs->reconfigurefunc = storeCossDirReconfigure;
    storefs->donefunc = storeCossDirDone;
    coss_state_pool = memPoolCreate("COSS IO State data", sizeof(CossState));
    coss_index_pool = memPoolCreate("COSS index data", sizeof(CossIndexNode));
    coss_initialised = 1;
}