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log_rec.c

/*-
 * See the file LICENSE for redistribution information.
 *
 * Copyright (c) 1996, 1997, 1998
 *    Sleepycat Software.  All rights reserved.
 */
/*
 * Copyright (c) 1995, 1996
 *    The President and Fellows of Harvard University.  All rights reserved.
 *
 * 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 by the University of
 *    California, Berkeley and its contributors.
 * 4. 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.
 */

#include "config.h"

#ifndef lint
static const char sccsid[] = "@(#)log_rec.c     10.26 (Sleepycat) 10/21/98";
#endif /* not lint */

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

#include <errno.h>
#include <string.h>
#endif

#include "db_int.h"
#include "shqueue.h"
#include "log.h"
#include "db_dispatch.h"
#include "common_ext.h"

static int __log_do_open __P((DB_LOG *,
    u_int8_t *, char *, DBTYPE, u_int32_t));
static int __log_lid_to_fname __P((DB_LOG *, u_int32_t, FNAME **));
static int __log_open_file __P((DB_LOG *, __log_register_args *));

/*
 * PUBLIC: int __log_register_recover
 * PUBLIC:     __P((DB_LOG *, DBT *, DB_LSN *, int, void *));
 */
int
__log_register_recover(logp, dbtp, lsnp, redo, info)
      DB_LOG *logp;
      DBT *dbtp;
      DB_LSN *lsnp;
      int redo;
      void *info;
{
      DB_ENTRY *dbe;
      __log_register_args *argp;
      int ret;

#ifdef DEBUG_RECOVER
      __log_register_print(logp, dbtp, lsnp, redo, info);
#endif
      COMPQUIET(info, NULL);
      COMPQUIET(lsnp, NULL);

      F_SET(logp, DBC_RECOVER);

      if ((ret = __log_register_read(dbtp->data, &argp)) != 0)
            goto out;

      if ((argp->opcode == LOG_CHECKPOINT && redo == TXN_OPENFILES) ||
          (argp->opcode == LOG_OPEN &&
          (redo == TXN_REDO || redo == TXN_OPENFILES ||
           redo == TXN_FORWARD_ROLL)) ||
          (argp->opcode == LOG_CLOSE &&
          (redo == TXN_UNDO || redo == TXN_BACKWARD_ROLL))) {
            /*
             * If we are redoing an open or undoing a close, then we need
             * to open a file.
             */
            ret = __log_open_file(logp, argp);
            if (ret == ENOENT) {
                  if (redo == TXN_OPENFILES)
                        __db_err(logp->dbenv, "warning: %s: %s",
                            argp->name.data, strerror(ENOENT));
                  ret = 0;
            }
      } else if (argp->opcode != LOG_CHECKPOINT &&
          argp->opcode != LOG_CLOSE) {
            /*
             * If we are undoing an open, then we need to close the file.
             * Note that we do *not* close the file if we are redoing a
             * close, because we do not log the reference counts on log
             * files and we may have had the file open multiple times,
             * and therefore, this close should just dec a reference
             * count.  However, since we only do one open during a
             * checkpoint, this will inadvertently close the file.
             *
             * If the file is deleted, then we can just ignore this close.
             * Otherwise, we should usually have a valid dbp we should
             * close or whose reference count should be decremented.
             * However, if we shut down without closing a file, we
             * may, in fact, not have the file open, and that's OK.
             */
            LOCK_LOGTHREAD(logp);
            if (argp->id < logp->dbentry_cnt) {
                  dbe = &logp->dbentry[argp->id];
                  if (dbe->dbp != NULL && --dbe->refcount == 0) {
                        ret = dbe->dbp->close(dbe->dbp, 0);
                        if (dbe->name != NULL) {
                              __os_freestr(dbe->name);
                              dbe->name = NULL;
                        }
                        (void)__log_rem_logid(logp, argp->id);
                  }
            }
            UNLOCK_LOGTHREAD(logp);
      } else if (argp->opcode == LOG_CHECKPOINT && redo == TXN_UNDO &&
          (argp->id >= logp->dbentry_cnt ||
          (!logp->dbentry[argp->id].deleted &&
          logp->dbentry[argp->id].dbp == NULL))) {
            /*
             * It's a checkpoint and we are rolling backward.  It
             * is possible that the system was shut down and thus
             * ended with a stable checkpoint; this file was never
             * closed and has therefore not been reopened yet.  If
             * so, we need to try to open it.
             */
            ret = __log_open_file(logp, argp);
            if (ret == ENOENT) {
                  __db_err(logp->dbenv, "warning: %s: %s",
                      argp->name.data, strerror(ENOENT));
                  ret = 0;
            }
      }

out:  F_CLR(logp, DBC_RECOVER);
      if (argp != NULL)
            __os_free(argp, 0);
      return (ret);
}

/* Hand coded routines. */

/*
 * Called during log_register recovery.  Make sure that we have an
 * entry in the dbentry table for this ndx.
 * Returns 0 on success, non-zero on error.
 */
static int
__log_open_file(lp, argp)
      DB_LOG *lp;
      __log_register_args *argp;
{
      DB_ENTRY *dbe;
  
      if (argp->name.size == 0)
            return(0);
  
      /*
       * Because of reference counting, we cannot automatically close files
       * during recovery, so when we're opening, we have to check that the
       * name we are opening is what we expect.  If it's not, then we close
       * the old file and open the new one.
       */
      LOCK_LOGTHREAD(lp);
      if (argp->id < lp->dbentry_cnt)
            dbe = &lp->dbentry[argp->id];
      else
            dbe = NULL;

      if (dbe != NULL && (dbe->deleted == 1 || dbe->dbp != NULL) &&
          dbe->name != NULL && argp->name.data != NULL &&
          strncmp(argp->name.data, dbe->name, argp->name.size) == 0) {

            dbe->refcount++;
            UNLOCK_LOGTHREAD(lp);
            return (0);
      }
      UNLOCK_LOGTHREAD(lp);

      if (dbe != NULL && dbe->dbp != NULL) {
                (void)dbe->dbp->close(dbe->dbp, 0);
            if (dbe->name != NULL)
                  __os_freestr(dbe->name);
                dbe->name = NULL;
            (void)__log_rem_logid(lp, argp->id);
        }


      return (__log_do_open(lp,
          argp->uid.data, argp->name.data, argp->ftype, argp->id));
}

/*
 * __log_do_open --
 *    Open files referenced in the log.  This is the part of the open that
 * is not protected by the thread mutex.
 */

static int
__log_do_open(lp, uid, name, ftype, ndx)
      DB_LOG *lp;
      u_int8_t *uid;
      char *name;
      DBTYPE ftype;
      u_int32_t ndx;
{
      DB *dbp;
      int ret;

      dbp = NULL;
      if ((ret = db_open(name, ftype, 0, 0, lp->dbenv, NULL, &dbp)) == 0) {
            /*
             * Verify that we are opening the same file that we were
             * referring to when we wrote this log record.
             */
            if (memcmp(uid, dbp->fileid, DB_FILE_ID_LEN) != 0) {
                  (void)dbp->close(dbp, 0);
                  dbp = NULL;
                  ret = ENOENT;
            }
      }

      if (ret == 0 || ret == ENOENT)
            (void)__log_add_logid(lp, dbp, name, ndx);

      return (ret);
}

/*
 * __log_add_logid --
 *    Adds a DB entry to the log's DB entry table.
 *
 * PUBLIC: int __log_add_logid __P((DB_LOG *, DB *, const char *, u_int32_t));
 */
int
__log_add_logid(logp, dbp, name, ndx)
      DB_LOG *logp;
      DB *dbp;
      const char *name;
      u_int32_t ndx;
{
      u_int32_t i;
      int ret;

      ret = 0;

      LOCK_LOGTHREAD(logp);

      /*
       * Check if we need to grow the table.  Note, ndx is 0-based (the
       * index into the DB entry table) an dbentry_cnt is 1-based, the
       * number of available slots.
       */
      if (logp->dbentry_cnt <= ndx) {
            if ((ret = __os_realloc(&logp->dbentry,
                (ndx + DB_GROW_SIZE) * sizeof(DB_ENTRY))) != 0)
                  goto err;

            /* Initialize the new entries. */
            for (i = logp->dbentry_cnt; i < ndx + DB_GROW_SIZE; i++) {
                  logp->dbentry[i].dbp = NULL;
                  logp->dbentry[i].deleted = 0;
                  logp->dbentry[i].name = NULL;
            }

            logp->dbentry_cnt = i;
      }

      /* Make space for the name and copy it in. */
      if (name != NULL) {
            if ((ret = __os_malloc(strlen(name) + 1, 
                NULL, &logp->dbentry[ndx].name)) != 0)
                  goto err;
            strcpy(logp->dbentry[ndx].name, name);
      }

      if (logp->dbentry[ndx].deleted == 0 && logp->dbentry[ndx].dbp == NULL) {
            logp->dbentry[ndx].dbp = dbp;
            logp->dbentry[ndx].refcount = 1;
            logp->dbentry[ndx].deleted = dbp == NULL;
      } else
            logp->dbentry[ndx].refcount++;


err:  UNLOCK_LOGTHREAD(logp);
      return (ret);
}


/*
 * __db_fileid_to_db --
 *    Return the DB corresponding to the specified fileid.
 *
 * PUBLIC: int __db_fileid_to_db __P((DB_LOG *, DB **, u_int32_t));
 */
int
__db_fileid_to_db(logp, dbpp, ndx)
      DB_LOG *logp;
      DB **dbpp;
      u_int32_t ndx;
{
      int ret;
      char *name;
      FNAME *fname;

      ret = 0;
      LOCK_LOGTHREAD(logp);

      /*
       * Under XA, a process different than the one issuing DB
       * operations may abort a transaction.  In this case, 
       * recovery routines are run by a process that does not
       * necessarily have the file open.  In this case, we must
       * open the file explicitly.
       */
      if (ndx >= logp->dbentry_cnt ||
          (!logp->dbentry[ndx].deleted && logp->dbentry[ndx].dbp == NULL)) {
            if (__log_lid_to_fname(logp, ndx, &fname) != 0) {
                  /* Couldn't find entry; this is a fatal error. */
                  ret = EINVAL;
                  goto err;
            }
            name = R_ADDR(logp, fname->name_off);
            /*
             * __log_do_open is called without protection of the
             * log thread lock.
             */
            UNLOCK_LOGTHREAD(logp);
            /*
             * At this point, we are not holding the thread lock, so
             * exit directly instead of going through the exit code
             * at the bottom.  If the __log_do_open succeeded, then
             * we don't need to do any of the remaining error checking
             * at the end of this routine.
             */
            if ((ret = __log_do_open(logp,
                fname->ufid, name, fname->s_type, ndx)) != 0)
                  return (ret);
            *dbpp = logp->dbentry[ndx].dbp;
            return (0);
      }

      /*
       * Return DB_DELETED if the file has been deleted
       * (it's not an error).
       */
      if (logp->dbentry[ndx].deleted) {
            ret = DB_DELETED;
            goto err;
      }

      /*
       * Otherwise return 0, but if we don't have a corresponding DB,
       * it's an error.
       */
      if ((*dbpp = logp->dbentry[ndx].dbp) == NULL)
            ret = ENOENT;

err:  UNLOCK_LOGTHREAD(logp);
      return (ret);
}

/*
 * Close files that were opened by the recovery daemon.
 *
 * PUBLIC: void __log_close_files __P((DB_LOG *));
 */
void
__log_close_files(logp)
      DB_LOG *logp;
{
      u_int32_t i;

      LOCK_LOGTHREAD(logp);
      for (i = 0; i < logp->dbentry_cnt; i++)
            if (logp->dbentry[i].dbp) {
                  logp->dbentry[i].dbp->close(logp->dbentry[i].dbp, 0);
                  logp->dbentry[i].dbp = NULL;
                  logp->dbentry[i].deleted = 0;
            }
      F_CLR(logp, DBC_RECOVER);
      UNLOCK_LOGTHREAD(logp);
}

/*
 * PUBLIC: void __log_rem_logid __P((DB_LOG *, u_int32_t));
 */
void
__log_rem_logid(logp, ndx)
      DB_LOG *logp;
      u_int32_t ndx;
{
      LOCK_LOGTHREAD(logp);
      if (--logp->dbentry[ndx].refcount == 0) {
            logp->dbentry[ndx].dbp = NULL;
            logp->dbentry[ndx].deleted = 0;
      }
      UNLOCK_LOGTHREAD(logp);
}

/*
 * __log_lid_to_fname --
 *    Traverse the shared-memory region looking for the entry that
 * matches the passed log fileid.  Returns 0 on success; -1 on error.
 */
static int
__log_lid_to_fname(dblp, lid, fnamep)
      DB_LOG *dblp;
      u_int32_t lid;
      FNAME **fnamep;
{
      FNAME *fnp;

      for (fnp = SH_TAILQ_FIRST(&dblp->lp->fq, __fname);
          fnp != NULL; fnp = SH_TAILQ_NEXT(fnp, q, __fname)) {
            if (fnp->ref == 0)      /* Entry not in use. */
                  continue;
            if (fnp->id == lid) {
                  *fnamep = fnp;
                  return (0);
            }
      }
      return (-1);
}

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