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Sourcecode: db4.2 version File versions  Download package

mp_fopen.c

/*-
 * See the file LICENSE for redistribution information.
 *
 * Copyright (c) 1996-2003
 *    Sleepycat Software.  All rights reserved.
 */
#include "db_config.h"

#ifndef lint
static const char revid[] = "$Id: mp_fopen.c,v 11.120 2003/11/07 18:45:15 ubell Exp $";
#endif /* not lint */

#ifndef NO_SYSTEM_INCLUDES
#include <sys/types.h>

#ifdef HAVE_RPC
#include <rpc/rpc.h>
#endif
#include <string.h>
#endif

#include "db_int.h"
#include "dbinc/db_shash.h"
#include "dbinc/log.h"
#include "dbinc/mp.h"

#ifdef HAVE_RPC
#include "dbinc_auto/db_server.h"
#include "dbinc_auto/rpc_client_ext.h"
#endif

static int __memp_fclose_pp __P((DB_MPOOLFILE *, u_int32_t));
static int __memp_fopen_pp __P((DB_MPOOLFILE *,
            const char *, u_int32_t, int, size_t));
static int __memp_get_clear_len __P((DB_MPOOLFILE *, u_int32_t *));
static int __memp_get_flags __P((DB_MPOOLFILE *, u_int32_t *));
static int __memp_get_lsn_offset __P((DB_MPOOLFILE *, int32_t *));
static int __memp_get_maxsize __P((DB_MPOOLFILE *, u_int32_t *, u_int32_t *));
static int __memp_set_maxsize __P((DB_MPOOLFILE *, u_int32_t, u_int32_t));
static int __memp_get_pgcookie __P((DB_MPOOLFILE *, DBT *));
static int __memp_get_priority __P((DB_MPOOLFILE *, DB_CACHE_PRIORITY *));
static int __memp_set_priority __P((DB_MPOOLFILE *, DB_CACHE_PRIORITY));

/*
 * __memp_fcreate_pp --
 *    DB_ENV->memp_fcreate pre/post processing.
 *
 * PUBLIC: int __memp_fcreate_pp __P((DB_ENV *, DB_MPOOLFILE **, u_int32_t));
 */
int
__memp_fcreate_pp(dbenv, retp, flags)
      DB_ENV *dbenv;
      DB_MPOOLFILE **retp;
      u_int32_t flags;
{
      int rep_check, ret;

      PANIC_CHECK(dbenv);

      /* Validate arguments. */
      if ((ret = __db_fchk(dbenv, "DB_ENV->memp_fcreate", flags, 0)) != 0)
            return (ret);

      rep_check = IS_ENV_REPLICATED(dbenv) ? 1 : 0;
      if (rep_check)
            __env_rep_enter(dbenv);
      ret = __memp_fcreate(dbenv, retp);
      if (rep_check)
            __env_rep_exit(dbenv);
      return (ret);
}

/*
 * __memp_fcreate --
 *    DB_ENV->memp_fcreate.
 *
 * PUBLIC: int __memp_fcreate __P((DB_ENV *, DB_MPOOLFILE **));
 */
int
__memp_fcreate(dbenv, retp)
      DB_ENV *dbenv;
      DB_MPOOLFILE **retp;
{
      DB_MPOOLFILE *dbmfp;
      int ret;

      /* Allocate and initialize the per-process structure. */
      if ((ret = __os_calloc(dbenv, 1, sizeof(DB_MPOOLFILE), &dbmfp)) != 0)
            return (ret);

      dbmfp->ref = 1;
      dbmfp->lsn_offset = -1;
      dbmfp->dbenv = dbenv;
      dbmfp->mfp = INVALID_ROFF;

#ifdef HAVE_RPC
      if (F_ISSET(dbenv, DB_ENV_RPCCLIENT)) {
            dbmfp->get_clear_len = __dbcl_memp_get_clear_len;
            dbmfp->set_clear_len = __dbcl_memp_set_clear_len;
            dbmfp->get_fileid = __dbcl_memp_get_fileid;
            dbmfp->set_fileid = __dbcl_memp_set_fileid;
            dbmfp->get_flags = __dbcl_memp_get_flags;
            dbmfp->set_flags = __dbcl_memp_set_flags;
            dbmfp->get_ftype = __dbcl_memp_get_ftype;
            dbmfp->set_ftype = __dbcl_memp_set_ftype;
            dbmfp->get_lsn_offset = __dbcl_memp_get_lsn_offset;
            dbmfp->set_lsn_offset = __dbcl_memp_set_lsn_offset;
            dbmfp->get_maxsize = __dbcl_memp_get_maxsize;
            dbmfp->set_maxsize = __dbcl_memp_set_maxsize;
            dbmfp->get_pgcookie = __dbcl_memp_get_pgcookie;
            dbmfp->set_pgcookie = __dbcl_memp_set_pgcookie;
            dbmfp->get_priority = __dbcl_memp_get_priority;
            dbmfp->set_priority = __dbcl_memp_set_priority;

            dbmfp->get = __dbcl_memp_fget;
            dbmfp->open = __dbcl_memp_fopen;
            dbmfp->put = __dbcl_memp_fput;
            dbmfp->set = __dbcl_memp_fset;
            dbmfp->sync = __dbcl_memp_fsync;
      } else
#endif
      {
            dbmfp->get_clear_len = __memp_get_clear_len;
            dbmfp->set_clear_len = __memp_set_clear_len;
            dbmfp->get_fileid = __memp_get_fileid;
            dbmfp->set_fileid = __memp_set_fileid;
            dbmfp->get_flags = __memp_get_flags;
            dbmfp->set_flags = __memp_set_flags;
            dbmfp->get_ftype = __memp_get_ftype;
            dbmfp->set_ftype = __memp_set_ftype;
            dbmfp->get_lsn_offset = __memp_get_lsn_offset;
            dbmfp->set_lsn_offset = __memp_set_lsn_offset;
            dbmfp->get_maxsize = __memp_get_maxsize;
            dbmfp->set_maxsize = __memp_set_maxsize;
            dbmfp->get_pgcookie = __memp_get_pgcookie;
            dbmfp->set_pgcookie = __memp_set_pgcookie;
            dbmfp->get_priority = __memp_get_priority;
            dbmfp->set_priority = __memp_set_priority;

            dbmfp->get = __memp_fget_pp;
            dbmfp->open = __memp_fopen_pp;
            dbmfp->put = __memp_fput_pp;
            dbmfp->set = __memp_fset_pp;
            dbmfp->sync = __memp_fsync_pp;
      }
      dbmfp->close = __memp_fclose_pp;

      *retp = dbmfp;
      return (0);
}

/*
 * __memp_get_clear_len --
 *    Get the clear length.
 */
static int
__memp_get_clear_len(dbmfp, clear_lenp)
      DB_MPOOLFILE *dbmfp;
      u_int32_t *clear_lenp;
{
      *clear_lenp = dbmfp->clear_len;
      return (0);
}

/*
 * __memp_set_clear_len --
 *    DB_MPOOLFILE->set_clear_len.
 *
 * PUBLIC: int __memp_set_clear_len __P((DB_MPOOLFILE *, u_int32_t));
 */
int
__memp_set_clear_len(dbmfp, clear_len)
      DB_MPOOLFILE *dbmfp;
      u_int32_t clear_len;
{
      MPF_ILLEGAL_AFTER_OPEN(dbmfp, "DB_MPOOLFILE->set_clear_len");

      dbmfp->clear_len = clear_len;
      return (0);
}

/*
 * __memp_get_fileid --
 *    DB_MPOOLFILE->get_fileid.
 *
 * PUBLIC: int __memp_get_fileid __P((DB_MPOOLFILE *, u_int8_t *));
 */
int
__memp_get_fileid(dbmfp, fileid)
      DB_MPOOLFILE *dbmfp;
      u_int8_t *fileid;
{
      if (!F_ISSET(dbmfp, MP_FILEID_SET)) {
            __db_err(dbmfp->dbenv, "get_fileid: file ID not set");
            return (EINVAL);
      }

      memcpy(fileid, dbmfp->fileid, DB_FILE_ID_LEN);
      return (0);
}

/*
 * __memp_set_fileid --
 *    DB_MPOOLFILE->set_fileid.
 *
 * PUBLIC: int __memp_set_fileid __P((DB_MPOOLFILE *, u_int8_t *));
 */
int
__memp_set_fileid(dbmfp, fileid)
      DB_MPOOLFILE *dbmfp;
      u_int8_t *fileid;
{
      MPF_ILLEGAL_AFTER_OPEN(dbmfp, "DB_MPOOLFILE->set_fileid");

      memcpy(dbmfp->fileid, fileid, DB_FILE_ID_LEN);
      F_SET(dbmfp, MP_FILEID_SET);

      return (0);
}

/*
 * __memp_get_flags --
 *    Get the DB_MPOOLFILE flags;
 */
static int
__memp_get_flags(dbmfp, flagsp)
      DB_MPOOLFILE *dbmfp;
      u_int32_t *flagsp;
{
      MPOOLFILE *mfp;

      mfp = dbmfp->mfp;

      *flagsp = 0;

      if (mfp == NULL)
            *flagsp = FLD_ISSET(dbmfp->config_flags, DB_MPOOL_NOFILE);
      else
            if (mfp->no_backing_file)
                  FLD_SET(*flagsp, DB_MPOOL_NOFILE);
      return (0);
}

/*
 * __memp_set_flags --
 *    Set the DB_MPOOLFILE flags;
 *
 * PUBLIC: int __memp_set_flags __P((DB_MPOOLFILE *, u_int32_t, int));
 */
int
__memp_set_flags(dbmfp, flags, onoff)
      DB_MPOOLFILE *dbmfp;
      u_int32_t flags;
      int onoff;
{
      DB_ENV *dbenv;
      MPOOLFILE *mfp;
      int ret;

      dbenv = dbmfp->dbenv;
      mfp = dbmfp->mfp;

#define     OKFLAGS     (DB_MPOOL_NOFILE | DB_MPOOL_UNLINK)
      if ((ret =
          __db_fchk(dbenv, "DB_MPOOLFILE->set_flags", flags, OKFLAGS)) != 0)
            return (ret);

      switch (flags) {
      case 0:
            break;
      case DB_MPOOL_NOFILE:
            if (mfp == NULL)
                  if (onoff)
                        FLD_SET(dbmfp->config_flags, DB_MPOOL_NOFILE);
                  else
                        FLD_CLR(dbmfp->config_flags, DB_MPOOL_NOFILE);
            else
                  mfp->no_backing_file = onoff;
            break;
      case DB_MPOOL_UNLINK:
            if (mfp == NULL)
                  if (onoff)
                        FLD_SET(dbmfp->config_flags, DB_MPOOL_UNLINK);
                  else
                        FLD_CLR(dbmfp->config_flags, DB_MPOOL_UNLINK);
            else
                  mfp->unlink_on_close = onoff;
            break;
      }
      return (0);
}

/*
 * __memp_get_ftype --
 *    Get the file type (as registered).
 *
 * PUBLIC: int __memp_get_ftype __P((DB_MPOOLFILE *, int *));
 */
int
__memp_get_ftype(dbmfp, ftypep)
      DB_MPOOLFILE *dbmfp;
      int *ftypep;
{
      *ftypep = dbmfp->ftype;
      return (0);
}

/*
 * __memp_set_ftype --
 *    DB_MPOOLFILE->set_ftype.
 *
 * PUBLIC: int __memp_set_ftype __P((DB_MPOOLFILE *, int));
 */
int
__memp_set_ftype(dbmfp, ftype)
      DB_MPOOLFILE *dbmfp;
      int ftype;
{
      MPF_ILLEGAL_AFTER_OPEN(dbmfp, "DB_MPOOLFILE->set_ftype");

      dbmfp->ftype = ftype;
      return (0);
}

/*
 * __memp_get_lsn_offset --
 *    Get the page's LSN offset.
 */
static int
__memp_get_lsn_offset(dbmfp, lsn_offsetp)
      DB_MPOOLFILE *dbmfp;
      int32_t *lsn_offsetp;
{
      *lsn_offsetp = dbmfp->lsn_offset;
      return (0);
}

/*
 * __memp_set_lsn_offset --
 *    Set the page's LSN offset.
 *
 * PUBLIC: int __memp_set_lsn_offset __P((DB_MPOOLFILE *, int32_t));
 */
int
__memp_set_lsn_offset(dbmfp, lsn_offset)
      DB_MPOOLFILE *dbmfp;
      int32_t lsn_offset;
{
      MPF_ILLEGAL_AFTER_OPEN(dbmfp, "DB_MPOOLFILE->set_lsn_offset");

      dbmfp->lsn_offset = lsn_offset;
      return (0);
}

/*
 * __memp_get_maxsize --
 *    Get the file's maximum size.
 */
static int
__memp_get_maxsize(dbmfp, gbytesp, bytesp)
      DB_MPOOLFILE *dbmfp;
      u_int32_t *gbytesp, *bytesp;
{
      DB_ENV *dbenv;
      DB_MPOOL *dbmp;
      MPOOLFILE *mfp;

      if ((mfp = dbmfp->mfp) == NULL) {
            *gbytesp = dbmfp->gbytes;
            *bytesp = dbmfp->bytes;
      } else {
            dbenv = dbmfp->dbenv;
            dbmp = dbenv->mp_handle;

            R_LOCK(dbenv, dbmp->reginfo);
            *gbytesp = mfp->maxpgno / (GIGABYTE / mfp->stat.st_pagesize);
            *bytesp = (mfp->maxpgno %
                (GIGABYTE / mfp->stat.st_pagesize)) * mfp->stat.st_pagesize;
            R_UNLOCK(dbenv, dbmp->reginfo);
      }

      return (0);
}

/*
 * __memp_set_maxsize --
 *    Set the files's maximum size.
 */
static int
__memp_set_maxsize(dbmfp, gbytes, bytes)
      DB_MPOOLFILE *dbmfp;
      u_int32_t gbytes, bytes;
{
      DB_ENV *dbenv;
      DB_MPOOL *dbmp;
      MPOOLFILE *mfp;

      if ((mfp = dbmfp->mfp) == NULL) {
            dbmfp->gbytes = gbytes;
            dbmfp->bytes = bytes;
      } else {
            dbenv = dbmfp->dbenv;
            dbmp = dbenv->mp_handle;

            R_LOCK(dbenv, dbmp->reginfo);
            mfp->maxpgno = gbytes * (GIGABYTE / mfp->stat.st_pagesize);
            mfp->maxpgno += (bytes +
                mfp->stat.st_pagesize - 1) / mfp->stat.st_pagesize;
            R_UNLOCK(dbenv, dbmp->reginfo);
      }

      return (0);
}

/*
 * __memp_get_pgcookie --
 *    Get the pgin/pgout cookie.
 */
static int
__memp_get_pgcookie(dbmfp, pgcookie)
      DB_MPOOLFILE *dbmfp;
      DBT *pgcookie;
{
      if (dbmfp->pgcookie == NULL) {
            pgcookie->size = 0;
            pgcookie->data = "";
      } else
            memcpy(pgcookie, dbmfp->pgcookie, sizeof(DBT));
      return (0);
}

/*
 * __memp_set_pgcookie --
 *    Set the pgin/pgout cookie.
 *
 * PUBLIC: int __memp_set_pgcookie __P((DB_MPOOLFILE *, DBT *));
 */
int
__memp_set_pgcookie(dbmfp, pgcookie)
      DB_MPOOLFILE *dbmfp;
      DBT *pgcookie;
{
      DB_ENV *dbenv;
      DBT *cookie;
      int ret;

      MPF_ILLEGAL_AFTER_OPEN(dbmfp, "DB_MPOOLFILE->set_pgcookie");
      dbenv = dbmfp->dbenv;

      if ((ret = __os_calloc(dbenv, 1, sizeof(*cookie), &cookie)) != 0)
            return (ret);
      if ((ret = __os_malloc(dbenv, pgcookie->size, &cookie->data)) != 0) {
            (void)__os_free(dbenv, cookie);
            return (ret);
      }

      memcpy(cookie->data, pgcookie->data, pgcookie->size);
      cookie->size = pgcookie->size;

      dbmfp->pgcookie = cookie;
      return (0);
}

/*
 * __memp_get_priority --
 *    Set the cache priority for pages from this file.
 */
static int
__memp_get_priority(dbmfp, priorityp)
      DB_MPOOLFILE *dbmfp;
      DB_CACHE_PRIORITY *priorityp;
{
      switch (dbmfp->priority) {
      case MPOOL_PRI_VERY_LOW:
            *priorityp = DB_PRIORITY_VERY_LOW;
            break;
      case MPOOL_PRI_LOW:
            *priorityp = DB_PRIORITY_LOW;
            break;
      case MPOOL_PRI_DEFAULT:
            *priorityp = DB_PRIORITY_DEFAULT;
            break;
      case MPOOL_PRI_HIGH:
            *priorityp = DB_PRIORITY_HIGH;
            break;
      case MPOOL_PRI_VERY_HIGH:
            *priorityp = DB_PRIORITY_VERY_HIGH;
            break;
      default:
            __db_err(dbmfp->dbenv,
                "DB_MPOOLFILE->get_priority: unknown priority value: %d",
                dbmfp->priority);
            return (EINVAL);
      }

      return (0);
}

/*
 * __memp_set_priority --
 *    Set the cache priority for pages from this file.
 */
static int
__memp_set_priority(dbmfp, priority)
      DB_MPOOLFILE *dbmfp;
      DB_CACHE_PRIORITY priority;
{
      switch (priority) {
      case DB_PRIORITY_VERY_LOW:
            dbmfp->priority = MPOOL_PRI_VERY_LOW;
            break;
      case DB_PRIORITY_LOW:
            dbmfp->priority = MPOOL_PRI_LOW;
            break;
      case DB_PRIORITY_DEFAULT:
            dbmfp->priority = MPOOL_PRI_DEFAULT;
            break;
      case DB_PRIORITY_HIGH:
            dbmfp->priority = MPOOL_PRI_HIGH;
            break;
      case DB_PRIORITY_VERY_HIGH:
            dbmfp->priority = MPOOL_PRI_VERY_HIGH;
            break;
      default:
            __db_err(dbmfp->dbenv,
                "DB_MPOOLFILE->set_priority: unknown priority value: %d",
                priority);
            return (EINVAL);
      }

      /* Update the underlying file if we've already opened it. */
      if (dbmfp->mfp != NULL)
            dbmfp->mfp->priority = priority;

      return (0);
}

/*
 * __memp_fopen_pp --
 *    DB_MPOOLFILE->open pre/post processing.
 */
static int
__memp_fopen_pp(dbmfp, path, flags, mode, pagesize)
      DB_MPOOLFILE *dbmfp;
      const char *path;
      u_int32_t flags;
      int mode;
      size_t pagesize;
{
      DB_ENV *dbenv;
      int rep_check, ret;

      dbenv = dbmfp->dbenv;

      PANIC_CHECK(dbenv);

      /* Validate arguments. */
      if ((ret = __db_fchk(dbenv, "DB_MPOOLFILE->open", flags,
          DB_CREATE | DB_DIRECT | DB_EXTENT |
          DB_NOMMAP | DB_ODDFILESIZE | DB_RDONLY | DB_TRUNCATE)) != 0)
            return (ret);

      /*
       * Require a non-zero, power-of-two pagesize, smaller than the
       * clear length.
       */
      if (pagesize == 0 || !POWER_OF_TWO(pagesize)) {
            __db_err(dbenv,
                "DB_MPOOLFILE->open: page sizes must be a power-of-2");
            return (EINVAL);
      }
      if (dbmfp->clear_len > pagesize) {
            __db_err(dbenv,
                "DB_MPOOLFILE->open: clear length larger than page size");
            return (EINVAL);
      }

      /* Read-only checks, and local flag. */
      if (LF_ISSET(DB_RDONLY) && path == NULL) {
            __db_err(dbenv,
                "DB_MPOOLFILE->open: temporary files can't be readonly");
            return (EINVAL);
      }

      rep_check = IS_ENV_REPLICATED(dbenv) ? 1 : 0;
      if (rep_check)
            __env_rep_enter(dbenv);
      ret = __memp_fopen(dbmfp, NULL, path, flags, mode, pagesize);
      if (rep_check)
            __env_rep_exit(dbenv);
      return (ret);
}

/*
 * __memp_fopen --
 *    DB_MPOOLFILE->open.
 *
 * PUBLIC: int __memp_fopen __P((DB_MPOOLFILE *,
 * PUBLIC:     MPOOLFILE *, const char *, u_int32_t, int, size_t));
 */
int
__memp_fopen(dbmfp, mfp, path, flags, mode, pagesize)
      DB_MPOOLFILE *dbmfp;
      MPOOLFILE *mfp;
      const char *path;
      u_int32_t flags;
      int mode;
      size_t pagesize;
{
      DB_ENV *dbenv;
      DB_MPOOL *dbmp;
      DB_MPOOLFILE *tmp_dbmfp;
      MPOOL *mp;
      db_pgno_t last_pgno;
      size_t maxmap;
      u_int32_t mbytes, bytes, oflags;
      int refinc, ret;
      char *rpath;
      void *p;

      dbenv = dbmfp->dbenv;
      dbmp = dbenv->mp_handle;
      mp = dbmp->reginfo[0].primary;
      refinc = ret = 0;
      rpath = NULL;

      /*
       * If it's a temporary file, delay the open until we actually need
       * to write the file, and we know we can't join any existing files.
       */
      if (path == NULL)
            goto alloc;

      /*
       * If our caller knows what mfp we're using, increment the ref count,
       * no need to search.
       *
       * We don't need to acquire a lock other than the mfp itself, because
       * we know there's another reference and it's not going away.
       */
      if (mfp != NULL) {
            MUTEX_LOCK(dbenv, &mfp->mutex);
            ++mfp->mpf_cnt;
            refinc = 1;
            MUTEX_UNLOCK(dbenv, &mfp->mutex);
      }

      /*
       * Get the real name for this file and open it.  If it's a Queue extent
       * file, it may not exist, and that's OK.
       */
      oflags = 0;
      if (LF_ISSET(DB_CREATE))
            oflags |= DB_OSO_CREATE;
      if (LF_ISSET(DB_DIRECT))
            oflags |= DB_OSO_DIRECT;
      if (LF_ISSET(DB_RDONLY)) {
            F_SET(dbmfp, MP_READONLY);
            oflags |= DB_OSO_RDONLY;
      }
      if ((ret =
          __db_appname(dbenv, DB_APP_DATA, path, 0, NULL, &rpath)) != 0)
            goto err;

      /*
       * Supply a page size so os_open can decide whether to turn buffering
       * off if the DB_DIRECT_DB flag is set.
       */
      if ((ret = __os_open_extend(dbenv, rpath,
          0, (u_int32_t)pagesize, oflags, mode, &dbmfp->fhp)) != 0) {
            if (!LF_ISSET(DB_EXTENT))
                  __db_err(dbenv, "%s: %s", rpath, db_strerror(ret));
            goto err;
      }

      /*
       * Cache file handles are shared, and have mutexes to protect the
       * underlying file handle across seek and read/write calls.
       */
      dbmfp->fhp->ref = 1;
      if (F_ISSET(dbenv, DB_ENV_THREAD) &&
          (ret = __db_mutex_setup(dbenv, dbmp->reginfo,
          &dbmfp->fhp->mutexp, MUTEX_ALLOC | MUTEX_THREAD)) != 0)
            goto err;

      /*
       * Figure out the file's size.
       *
       * !!!
       * We can't use off_t's here, or in any code in the mainline library
       * for that matter.  (We have to use them in the os stubs, of course,
       * as there are system calls that take them as arguments.)  The reason
       * is some customers build in environments where an off_t is 32-bits,
       * but still run where offsets are 64-bits, and they pay us a lot of
       * money.
       */
      if ((ret = __os_ioinfo(
          dbenv, rpath, dbmfp->fhp, &mbytes, &bytes, NULL)) != 0) {
            __db_err(dbenv, "%s: %s", rpath, db_strerror(ret));
            goto err;
      }

      /*
       * Get the file id if we weren't given one.  Generated file id's
       * don't use timestamps, otherwise there'd be no chance of any
       * other process joining the party.
       */
      if (!F_ISSET(dbmfp, MP_FILEID_SET) &&
          (ret = __os_fileid(dbenv, rpath, 0, dbmfp->fileid)) != 0)
            goto err;

      if (mfp != NULL) 
            goto check_map;

      /*
       * If not creating a temporary file, walk the list of MPOOLFILE's,
       * looking for a matching file.  Files backed by temporary files
       * or previously removed files can't match.
       *
       * DB_TRUNCATE support.
       *
       * The fileID is a filesystem unique number (e.g., a UNIX dev/inode
       * pair) plus a timestamp.  If files are removed and created in less
       * than a second, the fileID can be repeated.  The problem with
       * repetition happens when the file that previously had the fileID
       * value still has pages in the pool, since we don't want to use them
       * to satisfy requests for the new file.
       *
       * Because the DB_TRUNCATE flag reuses the dev/inode pair, repeated
       * opens with that flag set guarantees matching fileIDs when the
       * machine can open a file and then re-open with truncate within a
       * second.  For this reason, we pass that flag down, and, if we find
       * a matching entry, we ensure that it's never found again, and we
       * create a new entry for the current request.
       */
      R_LOCK(dbenv, dbmp->reginfo);
      for (mfp = SH_TAILQ_FIRST(&mp->mpfq, __mpoolfile);
          mfp != NULL; mfp = SH_TAILQ_NEXT(mfp, q, __mpoolfile)) {
            /* Skip dead files and temporary files. */
            if (mfp->deadfile || F_ISSET(mfp, MP_TEMP))
                  continue;

            /* Skip non-matching files. */
            if (memcmp(dbmfp->fileid, R_ADDR(dbmp->reginfo,
                mfp->fileid_off), DB_FILE_ID_LEN) != 0)
                  continue;

            /*
             * If the file is being truncated, remove it from the system
             * and create a new entry.
             *
             * !!!
             * We should be able to set mfp to NULL and break out of the
             * loop, but I like the idea of checking all the entries.
             */
            if (LF_ISSET(DB_TRUNCATE)) {
                  MUTEX_LOCK(dbenv, &mfp->mutex);
                  mfp->deadfile = 1;
                  MUTEX_UNLOCK(dbenv, &mfp->mutex);
                  continue;
            }

            /*
             * Some things about a file cannot be changed: the clear length,
             * page size, or lSN location.
             *
             * The file type can change if the application's pre- and post-
             * processing needs change.  For example, an application that
             * created a hash subdatabase in a database that was previously
             * all btree.
             *
             * !!!
             * We do not check to see if the pgcookie information changed,
             * or update it if it is.
             */
            if (dbmfp->clear_len != mfp->clear_len ||
                pagesize != mfp->stat.st_pagesize ||
                dbmfp->lsn_offset != mfp->lsn_off) {
                  __db_err(dbenv,
                "%s: clear length, page size or LSN location changed",
                      path);
                  R_UNLOCK(dbenv, dbmp->reginfo);
                  ret = EINVAL;
                  goto err;
            }

            /*
             * Check to see if this file has died while we waited.
             *
             * We normally don't lock the deadfile field when we read it as
             * we only care if the field is zero or non-zero.  We do lock
             * on read when searching for a matching MPOOLFILE so that two
             * threads of control don't race between setting the deadfile
             * bit and incrementing the reference count, that is, a thread
             * of control decrementing the reference count and then setting
             * deadfile because the reference count is 0 blocks us finding
             * the file without knowing it's about to be marked dead.
             */
            MUTEX_LOCK(dbenv, &mfp->mutex);
            if (mfp->deadfile) {
                  MUTEX_UNLOCK(dbenv, &mfp->mutex);
                  continue;
            }
            ++mfp->mpf_cnt;
            refinc = 1;
            MUTEX_UNLOCK(dbenv, &mfp->mutex);

            if (dbmfp->ftype != 0)
                  mfp->ftype = dbmfp->ftype;

            break;
      }
      R_UNLOCK(dbenv, dbmp->reginfo);

      if (mfp != NULL)
            goto check_map;

alloc:      /* Allocate and initialize a new MPOOLFILE. */
      if ((ret = __memp_alloc(
          dbmp, dbmp->reginfo, NULL, sizeof(MPOOLFILE), NULL, &mfp)) != 0)
            goto err;
      memset(mfp, 0, sizeof(MPOOLFILE));
      mfp->mpf_cnt = 1;
      mfp->ftype = dbmfp->ftype;
      mfp->stat.st_pagesize = pagesize;
      mfp->lsn_off = dbmfp->lsn_offset;
      mfp->clear_len = dbmfp->clear_len;
      mfp->priority = dbmfp->priority;
      if (dbmfp->gbytes != 0 || dbmfp->bytes != 0) {
            mfp->maxpgno =
                dbmfp->gbytes * (GIGABYTE / mfp->stat.st_pagesize);
            mfp->maxpgno += (dbmfp->bytes +
                mfp->stat.st_pagesize - 1) / mfp->stat.st_pagesize;
      }
      if (FLD_ISSET(dbmfp->config_flags, DB_MPOOL_NOFILE))
            mfp->no_backing_file = 1;
      if (FLD_ISSET(dbmfp->config_flags, DB_MPOOL_UNLINK))
            mfp->unlink_on_close = 1;

      if (LF_ISSET(DB_TXN_NOT_DURABLE))
            F_SET(mfp, MP_NOT_DURABLE);
      if (LF_ISSET(DB_DIRECT))
            F_SET(mfp, MP_DIRECT);
      if (LF_ISSET(DB_EXTENT))
            F_SET(mfp, MP_EXTENT);
      F_SET(mfp, MP_CAN_MMAP);

      if (path == NULL)
            F_SET(mfp, MP_TEMP);
      else {
            /*
             * Don't permit files that aren't a multiple of the pagesize,
             * and find the number of the last page in the file, all the
             * time being careful not to overflow 32 bits.
             *
             * During verify or recovery, we might have to cope with a
             * truncated file; if the file size is not a multiple of the
             * page size, round down to a page, we'll take care of the
             * partial page outside the mpool system.
             */
            if (bytes % pagesize != 0) {
                  if (LF_ISSET(DB_ODDFILESIZE))
                        bytes -= (u_int32_t)(bytes % pagesize);
                  else {
                        __db_err(dbenv,
                "%s: file size not a multiple of the pagesize", rpath);
                        ret = EINVAL;
                        goto err;
                  }
            }

            /*
             * If the user specifies DB_MPOOL_LAST or DB_MPOOL_NEW on a
             * page get, we have to increment the last page in the file.
             * Figure it out and save it away.
             *
             * Note correction: page numbers are zero-based, not 1-based.
             */
            last_pgno = (db_pgno_t)(mbytes * (MEGABYTE / pagesize));
            last_pgno += (db_pgno_t)(bytes / pagesize);
            if (last_pgno != 0)
                  --last_pgno;
            mfp->orig_last_pgno = mfp->last_pgno = last_pgno;

            /* Copy the file path into shared memory. */
            if ((ret = __memp_alloc(dbmp, dbmp->reginfo,
                NULL, strlen(path) + 1, &mfp->path_off, &p)) != 0)
                  goto err;
            memcpy(p, path, strlen(path) + 1);

            /* Copy the file identification string into shared memory. */
            if ((ret = __memp_alloc(dbmp, dbmp->reginfo,
                NULL, DB_FILE_ID_LEN, &mfp->fileid_off, &p)) != 0)
                  goto err;
            memcpy(p, dbmfp->fileid, DB_FILE_ID_LEN);
      }

      /* Copy the page cookie into shared memory. */
      if (dbmfp->pgcookie == NULL || dbmfp->pgcookie->size == 0) {
            mfp->pgcookie_len = 0;
            mfp->pgcookie_off = 0;
      } else {
            if ((ret = __memp_alloc(dbmp, dbmp->reginfo,
                NULL, dbmfp->pgcookie->size, &mfp->pgcookie_off, &p)) != 0)
                  goto err;
            memcpy(p, dbmfp->pgcookie->data, dbmfp->pgcookie->size);
            mfp->pgcookie_len = dbmfp->pgcookie->size;
      }

      /*
       * Prepend the MPOOLFILE to the list of MPOOLFILE's.
       */
      R_LOCK(dbenv, dbmp->reginfo);
      ret = __db_mutex_setup(dbenv, dbmp->reginfo, &mfp->mutex,
          MUTEX_NO_RLOCK);
      if (ret == 0)
            SH_TAILQ_INSERT_HEAD(&mp->mpfq, mfp, q, __mpoolfile);
      R_UNLOCK(dbenv, dbmp->reginfo);
      if (ret != 0)
            goto err;

check_map:
      /*
       * We need to verify that all handles open a file either durable or not
       * durable.  This needs to be cross process and cross sub-databases, so
       * mpool is the place to do it.
       */
      if (!LF_ISSET(DB_RDONLY) &&
           !LF_ISSET(DB_TXN_NOT_DURABLE) != !F_ISSET(mfp, MP_NOT_DURABLE)) {
            __db_err(dbenv,
           "Cannot open DURABLE and NOT DURABLE handles in the same file");
            ret = EINVAL;
            goto err;
      }
      /*
       * All paths to here have initialized the mfp variable to reference
       * the selected (or allocated) MPOOLFILE.
       */
      dbmfp->mfp = mfp;

      /*
       * Check to see if we can mmap the file.  If a file:
       *    + isn't temporary
       *    + is read-only
       *    + doesn't require any pgin/pgout support
       *    + the DB_NOMMAP flag wasn't set (in either the file open or
       *      the environment in which it was opened)
       *    + and is less than mp_mmapsize bytes in size
       *
       * we can mmap it instead of reading/writing buffers.  Don't do error
       * checking based on the mmap call failure.  We want to do normal I/O
       * on the file if the reason we failed was because the file was on an
       * NFS mounted partition, and we can fail in buffer I/O just as easily
       * as here.
       *
       * We'd like to test to see if the file is too big to mmap.  Since we
       * don't know what size or type off_t's or size_t's are, or the largest
       * unsigned integral type is, or what random insanity the local C
       * compiler will perpetrate, doing the comparison in a portable way is
       * flatly impossible.  Hope that mmap fails if the file is too large.
       */
#define     DB_MAXMMAPSIZE    (10 * 1024 * 1024)      /* 10 MB. */
      if (F_ISSET(mfp, MP_CAN_MMAP)) {
            maxmap = dbenv->mp_mmapsize == 0 ?
                DB_MAXMMAPSIZE : dbenv->mp_mmapsize;
            if (path == NULL)
                  F_CLR(mfp, MP_CAN_MMAP);
            else if (!F_ISSET(dbmfp, MP_READONLY))
                  F_CLR(mfp, MP_CAN_MMAP);
            else if (dbmfp->ftype != 0)
                  F_CLR(mfp, MP_CAN_MMAP);
            else if (LF_ISSET(DB_NOMMAP) || F_ISSET(dbenv, DB_ENV_NOMMAP))
                  F_CLR(mfp, MP_CAN_MMAP);
            else if (mbytes > maxmap / MEGABYTE ||
                (mbytes == maxmap / MEGABYTE && bytes >= maxmap % MEGABYTE))
                  F_CLR(mfp, MP_CAN_MMAP);

            dbmfp->addr = NULL;
            if (F_ISSET(mfp, MP_CAN_MMAP)) {
                  dbmfp->len = (size_t)mbytes * MEGABYTE + bytes;
                  if (__os_mapfile(dbenv, rpath,
                      dbmfp->fhp, dbmfp->len, 1, &dbmfp->addr) != 0) {
                        dbmfp->addr = NULL;
                        F_CLR(mfp, MP_CAN_MMAP);
                  }
            }
      }

      F_SET(dbmfp, MP_OPEN_CALLED);

      /*
       * Share the underlying file descriptor if that's possible.
       *
       * Add the file to the process' list of DB_MPOOLFILEs.
       */
      MUTEX_THREAD_LOCK(dbenv, dbmp->mutexp);

      for (tmp_dbmfp = TAILQ_FIRST(&dbmp->dbmfq);
          tmp_dbmfp != NULL; tmp_dbmfp = TAILQ_NEXT(tmp_dbmfp, q))
            if (dbmfp->mfp == tmp_dbmfp->mfp &&
                (F_ISSET(dbmfp, MP_READONLY) ||
                !F_ISSET(tmp_dbmfp, MP_READONLY))) {
                  if (dbmfp->fhp->mutexp != NULL)
                        __db_mutex_free(
                            dbenv, dbmp->reginfo, dbmfp->fhp->mutexp);
                  (void)__os_closehandle(dbenv, dbmfp->fhp);

                  ++tmp_dbmfp->fhp->ref;
                  dbmfp->fhp = tmp_dbmfp->fhp;
                  break;
            }

      TAILQ_INSERT_TAIL(&dbmp->dbmfq, dbmfp, q);

      MUTEX_THREAD_UNLOCK(dbenv, dbmp->mutexp);

      if (0) {
err:        if (refinc) {
                  MUTEX_LOCK(dbenv, &mfp->mutex);
                  --mfp->mpf_cnt;
                  MUTEX_UNLOCK(dbenv, &mfp->mutex);
            }

      }
      if (rpath != NULL)
            __os_free(dbenv, rpath);
      return (ret);
}

/*
 * __memp_last_pgno --
 *    Return the page number of the last page in the file.
 *
 * !!!
 * Undocumented interface: DB private.
 *
 * PUBLIC: void __memp_last_pgno __P((DB_MPOOLFILE *, db_pgno_t *));
 */
void
__memp_last_pgno(dbmfp, pgnoaddr)
      DB_MPOOLFILE *dbmfp;
      db_pgno_t *pgnoaddr;
{
      DB_ENV *dbenv;
      DB_MPOOL *dbmp;

      dbenv = dbmfp->dbenv;
      dbmp = dbenv->mp_handle;

      R_LOCK(dbenv, dbmp->reginfo);
      *pgnoaddr = dbmfp->mfp->last_pgno;
      R_UNLOCK(dbenv, dbmp->reginfo);
}

/*
 * memp_fclose_pp --
 *    DB_MPOOLFILE->close pre/post processing.
 */
static int
__memp_fclose_pp(dbmfp, flags)
      DB_MPOOLFILE *dbmfp;
      u_int32_t flags;
{
      DB_ENV *dbenv;
      int rep_check, ret, t_ret;

      dbenv = dbmfp->dbenv;

      /*
       * Validate arguments, but as a handle destructor, we can't fail.
       *
       * !!!
       * DB_MPOOL_DISCARD: Undocumented flag: DB private.
       */
      ret = __db_fchk(dbenv, "DB_MPOOLFILE->close", flags, DB_MPOOL_DISCARD);

      rep_check = IS_ENV_REPLICATED(dbenv) ? 1 : 0;
      if (rep_check)
            __env_rep_enter(dbenv);
      if ((t_ret = __memp_fclose(dbmfp, flags)) != 0 && ret == 0)
            ret = t_ret;
      if (rep_check)
            __env_rep_exit(dbenv);
      return (ret);
}

/*
 * __memp_fclose --
 *    DB_MPOOLFILE->close.
 *
 * PUBLIC: int __memp_fclose __P((DB_MPOOLFILE *, u_int32_t));
 */
int
__memp_fclose(dbmfp, flags)
      DB_MPOOLFILE *dbmfp;
      u_int32_t flags;
{
      DB_ENV *dbenv;
      DB_MPOOL *dbmp;
      MPOOLFILE *mfp;
      char *rpath;
      u_int32_t ref;
      int deleted, ret, t_ret;

      dbenv = dbmfp->dbenv;
      dbmp = dbenv->mp_handle;
      ret = 0;

      /*
       * Remove the DB_MPOOLFILE from the process' list.
       *
       * It's possible the underlying mpool cache may never have been created.
       * In that case, all we have is a structure, discard it.
       *
       * It's possible the DB_MPOOLFILE was never added to the DB_MPOOLFILE
       * file list, check the MP_OPEN_CALLED flag to be sure.
       */
      if (dbmp == NULL)
            goto done;

      MUTEX_THREAD_LOCK(dbenv, dbmp->mutexp);

      DB_ASSERT(dbmfp->ref >= 1);
      if ((ref = --dbmfp->ref) == 0 && F_ISSET(dbmfp, MP_OPEN_CALLED))
            TAILQ_REMOVE(&dbmp->dbmfq, dbmfp, q);

      /*
       * Decrement the file descriptor's ref count -- if we're the last ref,
       * we'll discard the file descriptor.
       */
      if (ref == 0 && dbmfp->fhp != NULL && --dbmfp->fhp->ref > 0)
            dbmfp->fhp = NULL;
      MUTEX_THREAD_UNLOCK(dbenv, dbmp->mutexp);
      if (ref != 0)
            return (0);

      /* Complain if pinned blocks never returned. */
      if (dbmfp->pinref != 0) {
            __db_err(dbenv, "%s: close: %lu blocks left pinned",
                __memp_fn(dbmfp), (u_long)dbmfp->pinref);
            ret = __db_panic(dbenv, DB_RUNRECOVERY);
      }

      /* Discard any mmap information. */
      if (dbmfp->addr != NULL &&
          (ret = __os_unmapfile(dbenv, dbmfp->addr, dbmfp->len)) != 0)
            __db_err(dbenv, "%s: %s", __memp_fn(dbmfp), db_strerror(ret));

      /*
       * Close the file and discard the descriptor structure; temporary
       * files may not yet have been created.
       */
      if (dbmfp->fhp != NULL) {
            if (dbmfp->fhp->mutexp != NULL) {
                  __db_mutex_free(
                      dbenv, dbmp->reginfo, dbmfp->fhp->mutexp);
                  dbmfp->fhp->mutexp = NULL;
            }
            if ((t_ret = __os_closehandle(dbenv, dbmfp->fhp)) != 0) {
                  __db_err(dbenv, "%s: %s",
                      __memp_fn(dbmfp), db_strerror(t_ret));
                  if (ret == 0)
                        ret = t_ret;
            }
            dbmfp->fhp = NULL;
      }

      /*
       * Discard our reference on the underlying MPOOLFILE, and close it
       * if it's no longer useful to anyone.  It possible the open of the
       * file never happened or wasn't successful, in which case, mpf will
       * be NULL and MP_OPEN_CALLED will not be set.
       */
      mfp = dbmfp->mfp;
      DB_ASSERT((F_ISSET(dbmfp, MP_OPEN_CALLED) && mfp != NULL) ||
          (!F_ISSET(dbmfp, MP_OPEN_CALLED) && mfp == NULL));
      if (!F_ISSET(dbmfp, MP_OPEN_CALLED))
            goto done;

      /*
       * If it's a temp file, all outstanding references belong to unflushed
       * buffers.  (A temp file can only be referenced by one DB_MPOOLFILE).
       * We don't care about preserving any of those buffers, so mark the
       * MPOOLFILE as dead so that even the dirty ones just get discarded
       * when we try to flush them.
       */
      deleted = 0;
      MUTEX_LOCK(dbenv, &mfp->mutex);
      if (--mfp->mpf_cnt == 0 || LF_ISSET(DB_MPOOL_DISCARD)) {
            if (LF_ISSET(DB_MPOOL_DISCARD) ||
                F_ISSET(mfp, MP_TEMP) || mfp->unlink_on_close)
                  mfp->deadfile = 1;
            if (mfp->unlink_on_close) {
                  if ((t_ret = __db_appname(dbmp->dbenv,
                      DB_APP_DATA, R_ADDR(dbmp->reginfo,
                      mfp->path_off), 0, NULL, &rpath)) != 0 && ret == 0)
                        ret = t_ret;
                  if (t_ret == 0) {
                        if ((t_ret = __os_unlink(
                            dbmp->dbenv, rpath) != 0) && ret == 0)
                              ret = t_ret;
                        __os_free(dbenv, rpath);
                  }
            }
            if (mfp->block_cnt == 0) {
                  if ((t_ret =
                      __memp_mf_discard(dbmp, mfp)) != 0 && ret == 0)
                        ret = t_ret;
                  deleted = 1;
            }
      }
      if (deleted == 0)
            MUTEX_UNLOCK(dbenv, &mfp->mutex);

done: /* Discard the DB_MPOOLFILE structure. */
      if (dbmfp->pgcookie != NULL) {
            __os_free(dbenv, dbmfp->pgcookie->data);
            __os_free(dbenv, dbmfp->pgcookie);
      }
      __os_free(dbenv, dbmfp);

      return (ret);
}

/*
 * __memp_mf_sync --
 *     sync an MPOOLFILE.  Should only be used when
 * the file is not already open in this process.
 *
 * PUBLIC: int __memp_mf_sync __P((DB_MPOOL *, MPOOLFILE *));
 */
int
__memp_mf_sync(dbmp, mfp)
      DB_MPOOL *dbmp;
      MPOOLFILE *mfp;
{
      DB_ENV *dbenv;
      DB_FH *fhp;
      int ret, t_ret;
      char *rpath;

      dbenv = dbmp->dbenv;

      if ((ret = __db_appname(dbenv, DB_APP_DATA,
          R_ADDR(dbmp->reginfo, mfp->path_off), 0, NULL, &rpath)) == 0) {
            if ((ret = __os_open(dbenv, rpath, 0, 0, &fhp)) == 0) {
                  ret = __os_fsync(dbenv, fhp);
                  if ((t_ret =
                      __os_closehandle(dbenv, fhp)) != 0 && ret == 0)
                        ret = t_ret;
            }
            __os_free(dbenv, rpath);
      }

      return (ret);
}

/*
 * __memp_mf_discard --
 *    Discard an MPOOLFILE.
 *
 * PUBLIC: int __memp_mf_discard __P((DB_MPOOL *, MPOOLFILE *));
 */
int
__memp_mf_discard(dbmp, mfp)
      DB_MPOOL *dbmp;
      MPOOLFILE *mfp;
{
      DB_ENV *dbenv;
      DB_MPOOL_STAT *sp;
      MPOOL *mp;
      int ret;

      dbenv = dbmp->dbenv;
      mp = dbmp->reginfo[0].primary;
      ret = 0;

      /*
       * Expects caller to be holding the MPOOLFILE mutex.
       *
       * When discarding a file, we have to flush writes from it to disk.
       * The scenario is that dirty buffers from this file need to be
       * flushed to satisfy a future checkpoint, but when the checkpoint
       * calls mpool sync, the sync code won't know anything about them.
       */
      if (mfp->file_written && !mfp->deadfile)
            ret = __memp_mf_sync(dbmp, mfp);

      /*
       * We have to release the MPOOLFILE lock before acquiring the region
       * lock so that we don't deadlock.  Make sure nobody ever looks at
       * this structure again.
       */
      mfp->deadfile = 1;

      /* Discard the mutex we're holding. */
      MUTEX_UNLOCK(dbenv, &mfp->mutex);

      /* Delete from the list of MPOOLFILEs. */
      R_LOCK(dbenv, dbmp->reginfo);
      SH_TAILQ_REMOVE(&mp->mpfq, mfp, q, __mpoolfile);

      /* Copy the statistics into the region. */
      sp = &mp->stat;
      sp->st_cache_hit += mfp->stat.st_cache_hit;
      sp->st_cache_miss += mfp->stat.st_cache_miss;
      sp->st_map += mfp->stat.st_map;
      sp->st_page_create += mfp->stat.st_page_create;
      sp->st_page_in += mfp->stat.st_page_in;
      sp->st_page_out += mfp->stat.st_page_out;

      /* Clear the mutex this MPOOLFILE recorded. */
      __db_shlocks_clear(&mfp->mutex, dbmp->reginfo,
          (REGMAINT *)R_ADDR(dbmp->reginfo, mp->maint_off));

      /* Free the space. */
      if (mfp->path_off != 0)
            __db_shalloc_free(dbmp->reginfo[0].addr,
                R_ADDR(dbmp->reginfo, mfp->path_off));
      if (mfp->fileid_off != 0)
            __db_shalloc_free(dbmp->reginfo[0].addr,
                R_ADDR(dbmp->reginfo, mfp->fileid_off));
      if (mfp->pgcookie_off != 0)
            __db_shalloc_free(dbmp->reginfo[0].addr,
                R_ADDR(dbmp->reginfo, mfp->pgcookie_off));
      __db_shalloc_free(dbmp->reginfo[0].addr, mfp);

      R_UNLOCK(dbenv, dbmp->reginfo);

      return (ret);
}

/*
 * __memp_fn --
 *    On errors we print whatever is available as the file name.
 *
 * PUBLIC: char * __memp_fn __P((DB_MPOOLFILE *));
 */
char *
__memp_fn(dbmfp)
      DB_MPOOLFILE *dbmfp;
{
      return (__memp_fns(dbmfp->dbenv->mp_handle, dbmfp->mfp));
}

/*
 * __memp_fns --
 *    On errors we print whatever is available as the file name.
 *
 * PUBLIC: char * __memp_fns __P((DB_MPOOL *, MPOOLFILE *));
 *
 */
char *
__memp_fns(dbmp, mfp)
      DB_MPOOL *dbmp;
      MPOOLFILE *mfp;
{
      if (mfp->path_off == 0)
            return ((char *)"temporary");

      return ((char *)R_ADDR(dbmp->reginfo, mfp->path_off));
}

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