log_rec.c

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/*-
 * See the file LICENSE for redistribution information.
 *
 * Copyright (c) 1996, 1997, 1998, 1999, 2000
 *      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. 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 revid[] = "$Id: log__rec_8c-source.html,v 1.1 2008/06/08 10:20:28 sebdiaz Exp $";
#endif /* not lint */

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

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

#include "db_int.h"
#include "db_page.h"
#include "db_ext.h"
#include "log.h"

static int __log_do_open __P((DB_ENV *, DB_LOG *,
    u_int8_t *, char *, DBTYPE, int32_t, db_pgno_t));
static int __log_lid_to_fname __P((DB_LOG *, int32_t, FNAME **));
static int __log_open_file __P((DB_ENV *, DB_LOG *, __log_register_args *));

/*
 * PUBLIC: int CDB___log_register_recover
 * PUBLIC:     __P((DB_ENV *, DBT *, DB_LSN *, db_recops, void *));
 */
int
CDB___log_register_recover(dbenv, dbtp, lsnp, op, info)
        DB_ENV *dbenv;
        DBT *dbtp;
        DB_LSN *lsnp;
        db_recops op;
        void *info;
{
        DB_ENTRY *dbe;
        DB_LOG *logp;
        DB *dbp;
        __log_register_args *argp;
        int do_rem, ret, t_ret;

        logp = dbenv->lg_handle;
        dbp = NULL;

#ifdef DEBUG_RECOVER
        CDB___log_register_print(logp, dbtp, lsnp, op, info);
#endif
        COMPQUIET(lsnp, NULL);

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

        if ((argp->opcode == LOG_OPEN &&
            (DB_REDO(op) || op == DB_TXN_OPENFILES)) ||
            (argp->opcode == LOG_CLOSE && DB_UNDO(op))) {
                /*
                 * If we are redoing an open or undoing a close, then we need
                 * to open a file.  We must open the file even if
                 * the meta page is not yet written as we may be creating it.
                 */
                if (op == DB_TXN_OPENFILES)
                        F_SET(logp, DBLOG_FORCE_OPEN);
                ret = __log_open_file(dbenv, logp, argp);
                F_CLR(logp, DBLOG_FORCE_OPEN);
                if (ret == ENOENT || ret == EINVAL) {
                        if (op == DB_TXN_OPENFILES && argp->name.size != 0 &&
                            (ret = CDB___db_txnlist_delete(dbenv, info,
                                argp->name.data, argp->fileid, 0)) != 0)
                                goto out;
                        ret = 0;
                }
        } else if (argp->opcode != LOG_CHECKPOINT) {
                /*
                 * If we are undoing an open, then we need to 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.
                 */
                do_rem = 0;
                MUTEX_THREAD_LOCK(logp->mutexp);
                if (argp->fileid < logp->dbentry_cnt) {
                        dbe = &logp->dbentry[argp->fileid];
                        if (dbe->refcount == 1) {
                                ret = CDB___db_txnlist_close(info,
                                    argp->fileid, dbe->count);
                                if ((dbp = TAILQ_FIRST(&dbe->dblist)) != NULL)
                                        (void) CDB_log_unregister(dbenv, dbp);
                                do_rem = 1;
                        } else
                                dbe->refcount--;
                }
                MUTEX_THREAD_UNLOCK(logp->mutexp);
                if (do_rem) {
                        (void)CDB___log_rem_logid(logp, dbp, argp->fileid);
                        /*
                         * If remove or rename has closed the file, don't
                         * sync.
                         */
                        if (dbp != NULL &&
                            (t_ret = dbp->close(dbp,
                            dbp->mpf == NULL ? DB_NOSYNC : 0)) != 0 && ret == 0)
                                ret = t_ret;
                }
        } else if (DB_UNDO(op) || op == DB_TXN_OPENFILES) {
                /*
                 * 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(dbenv, logp, argp);
                if (ret == ENOENT || ret == EINVAL) {
                        if (argp->name.size != 0 && (ret =
                            CDB___db_txnlist_delete(dbenv, info,
                                argp->name.data, argp->fileid, 0)) != 0)
                                goto out;
                        ret = 0;
                }
        }

out:    if (argp != NULL)
                CDB___os_free(argp, 0);
        return (ret);
}

/*
 * __log_open_file --
 *      Called during CDB_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(dbenv, lp, argp)
        DB_ENV *dbenv;
        DB_LOG *lp;
        __log_register_args *argp;
{
        DB_ENTRY *dbe;
        DB *dbp;

        /*
         * We never re-open temporary files.  Temp files are only
         * useful during aborts in which case the dbp was entered
         * when the file was registered.  During recovery, we treat
         * temp files as properly deleted files, allowing the open to
         * fail and not reporting any errors when recovery fails to
         * get a valid dbp from db_fileid_to_db.
         */
        if (argp->name.size == 0) {
                (void)CDB___log_add_logid(dbenv, lp, NULL, argp->fileid);
                return (ENOENT);
        }

        /*
         * 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.
         */
        MUTEX_THREAD_LOCK(lp->mutexp);
        if (argp->fileid < lp->dbentry_cnt)
                dbe = &lp->dbentry[argp->fileid];
        else
                dbe = NULL;

        if (dbe != NULL) {
                dbe->deleted = 0;
                if ((dbp = TAILQ_FIRST(&dbe->dblist)) != NULL) {
                        if (dbp->meta_pgno != argp->meta_pgno ||
                            memcmp(dbp->fileid,
                            argp->uid.data, DB_FILE_ID_LEN) != 0) {
                                MUTEX_THREAD_UNLOCK(lp->mutexp);
                                goto reopen;
                        }
                        if (!F_ISSET(lp, DBLOG_RECOVER))
                                dbe->refcount++;
                        MUTEX_THREAD_UNLOCK(lp->mutexp);
                        return (0);
                }
        }

        MUTEX_THREAD_UNLOCK(lp->mutexp);
        if (0) {
reopen:         (void) CDB_log_unregister(dbp->dbenv, dbp);
                (void) CDB___log_rem_logid(lp, dbp, argp->fileid);
                dbp->close(dbp, 0);
        }

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

/*
 * log_reopen_file -- close and reopen a db file.
 *      Must be called when a metadata page changes.
 *
 * PUBLIC: int CDB___log_reopen_file __P((DB_ENV *,
 * PUBLIC:     char *, int32_t, u_int8_t *, db_pgno_t));
 *
 */
int
CDB___log_reopen_file(dbenv, name, ndx, fileid, meta_pgno)
        DB_ENV *dbenv;
        char *name;
        int32_t ndx;
        u_int8_t *fileid;
        db_pgno_t meta_pgno;
{
        DB *dbp;
        DB_LOG *logp;
        DBTYPE ftype;
        int ret;

        logp = dbenv->lg_handle;

        if ((ret = CDB___db_fileid_to_db(dbenv, &dbp, ndx, 0)) != 0)
                goto out;
        ftype = dbp->type;
        (void) CDB_log_unregister(dbenv, dbp);
        (void) CDB___log_rem_logid(logp, dbp, ndx);
        (void) dbp->close(dbp, 0);

        ret = __log_do_open(dbenv, logp, fileid, name, ftype, ndx, meta_pgno);

out:    return (ret);
}

/*
 * __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(dbenv, lp, uid, name, ftype, ndx, meta_pgno)
        DB_ENV *dbenv;
        DB_LOG *lp;
        u_int8_t *uid;
        char *name;
        DBTYPE ftype;
        int32_t ndx;
        db_pgno_t meta_pgno;
{
        DB *dbp;
        int ret;
        u_int8_t zeroid[DB_FILE_ID_LEN];

        if ((ret = CDB_db_create(&dbp, lp->dbenv, 0)) != 0)
                return (ret);

        dbp->log_fileid = ndx;

        /*
         * This is needed to signal to the locking routines called while
         * opening databases that we are potentially undoing a transaction
         * from an XA process.  Since the XA process does not share
         * locks with the aborting transaction this prevents us from
         * deadlocking during the open during rollback.
         * Because this routine is called either during recovery or during an
         * XA_ABORT, we can safely set DB_AM_RECOVER in the dbp since it
         * will not be shared with other threads.
         */
        F_SET(dbp, DB_AM_RECOVER);
        if (meta_pgno != PGNO_BASE_MD)
                memcpy(dbp->fileid, uid, DB_FILE_ID_LEN);
        dbp->type = ftype;
        if ((ret = CDB___db_dbopen(dbp, name, 0, 0600, meta_pgno)) == 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) {
                        memset(zeroid, 0, DB_FILE_ID_LEN);
                        if (memcmp(dbp->fileid, zeroid, DB_FILE_ID_LEN) != 0)
                                goto not_right;
                        memcpy(dbp->fileid, uid, DB_FILE_ID_LEN);
                }
                if (IS_RECOVERING(dbenv)) {
                        (void)CDB_log_register(dbp->dbenv, dbp, name);
                        (void)CDB___log_add_logid(dbenv, lp, dbp, ndx);
                }
                return (0);
        }

not_right:
        (void)dbp->close(dbp, 0);
        (void)CDB___log_add_logid(dbenv, lp, NULL, ndx);

        return (ENOENT);
}

/*
 * CDB___log_add_logid --
 *      Adds a DB entry to the log's DB entry table.
 *
 * PUBLIC: int CDB___log_add_logid __P((DB_ENV *, DB_LOG *, DB *, int32_t));
 */
int
CDB___log_add_logid(dbenv, logp, dbp, ndx)
        DB_ENV *dbenv;
        DB_LOG *logp;
        DB *dbp;
        int32_t ndx;
{
        int32_t i;
        int ret;

        ret = 0;

        MUTEX_THREAD_LOCK(logp->mutexp);

        /*
         * 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 = CDB___os_realloc(dbenv,
                    (ndx + DB_GROW_SIZE) * sizeof(DB_ENTRY),
                    NULL, &logp->dbentry)) != 0)
                        goto err;

                /* Initialize the new entries. */
                for (i = logp->dbentry_cnt; i < ndx + DB_GROW_SIZE; i++) {
                        logp->dbentry[i].count = 0;
                        TAILQ_INIT(&logp->dbentry[i].dblist);
                        logp->dbentry[i].deleted = 0;
                        logp->dbentry[i].refcount = 0;
                }

                logp->dbentry_cnt = i;
        }

        if (logp->dbentry[ndx].deleted == 0 &&
            TAILQ_FIRST(&logp->dbentry[ndx].dblist) == NULL) {
                logp->dbentry[ndx].count = 0;
                if (dbp != NULL)
                        TAILQ_INSERT_HEAD(&logp->dbentry[ndx].dblist,
                            dbp, links);
                logp->dbentry[ndx].deleted = dbp == NULL;
                logp->dbentry[ndx].refcount = 1;
        } else if (!F_ISSET(logp, DBLOG_RECOVER)) {
                if (dbp != NULL)
                        TAILQ_INSERT_HEAD(&logp->dbentry[ndx].dblist,
                            dbp, links);
                logp->dbentry[ndx].refcount++;
        }

err:    MUTEX_THREAD_UNLOCK(logp->mutexp);
        return (ret);
}

/*
 * CDB___db_fileid_to_db --
 *      Return the DB corresponding to the specified fileid.
 *
 * PUBLIC: int CDB___db_fileid_to_db __P((DB_ENV *, DB **, int32_t, int));
 */
int
CDB___db_fileid_to_db(dbenv, dbpp, ndx, inc)
        DB_ENV *dbenv;
        DB **dbpp;
        int32_t ndx;
        int inc;
{
        DB_LOG *logp;
        DB *dbp;
        FNAME *fname;
        int ret;
        char *name;

        ret = 0;
        logp = dbenv->lg_handle;

        MUTEX_THREAD_LOCK(logp->mutexp);

        /*
         * 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, so we
         * we must open the file explicitly.
         */
        if (ndx >= logp->dbentry_cnt ||
            (!logp->dbentry[ndx].deleted &&
            (dbp = TAILQ_FIRST(&logp->dbentry[ndx].dblist)) == NULL)) {
                if (F_ISSET(logp, DBLOG_RECOVER)) {
                        ret = ENOENT;
                        goto err;
                }
                if (__log_lid_to_fname(logp, ndx, &fname) != 0) {
                        /* Couldn't find entry; this is a fatal error. */
                        CDB___db_err(dbenv, "Missing log fileid entry");
                        ret = EINVAL;
                        goto err;
                }
                name = R_ADDR(&logp->reginfo, fname->name_off);

                /*
                 * __log_do_open is called without protection of the
                 * log thread lock.
                 */
                MUTEX_THREAD_UNLOCK(logp->mutexp);

                /*
                 * 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(dbenv, logp,
                    fname->ufid, name, fname->s_type,
                    ndx, fname->meta_pgno)) != 0)
                        return (ret);

                *dbpp = TAILQ_FIRST(&logp->dbentry[ndx].dblist);
                return (0);
        }

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

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

err:    MUTEX_THREAD_UNLOCK(logp->mutexp);
        return (ret);
}

/*
 * Close files that were opened by the recovery daemon.
 *
 * PUBLIC: void CDB___log_close_files __P((DB_ENV *));
 */
void
CDB___log_close_files(dbenv)
        DB_ENV *dbenv;
{
        DB_ENTRY *dbe;
        DB_LOG *logp;
        DB *dbp;
        int32_t i;

        logp = dbenv->lg_handle;
        MUTEX_THREAD_LOCK(logp->mutexp);
        for (i = 0; i < logp->dbentry_cnt; i++) {
                dbe = &logp->dbentry[i];
                while ((dbp = TAILQ_FIRST(&dbe->dblist)) != NULL) {
                        (void)CDB_log_unregister(dbenv, dbp);
                        TAILQ_REMOVE(&dbe->dblist, dbp, links);
                        (void)dbp->close(dbp, 0);
                }
                dbe->deleted = 0;
                dbe->refcount = 0;
        }
        MUTEX_THREAD_UNLOCK(logp->mutexp);
}

/*
 * CDB___log_rem_logid
 *      Remove an entry from the log table.  Find the appropriate DB and
 * unlink it from the linked list off the table.  If the DB is NULL, treat
 * this as a simple refcount decrement.
 *
 * PUBLIC: void CDB___log_rem_logid __P((DB_LOG *, DB *, int32_t));
 */
void
CDB___log_rem_logid(logp, dbp, ndx)
        DB_LOG *logp;
        DB *dbp;
        int32_t ndx;
{
        DB *xdbp;

        MUTEX_THREAD_LOCK(logp->mutexp);
        if (--logp->dbentry[ndx].refcount == 0) {
                TAILQ_INIT(&logp->dbentry[ndx].dblist);
                logp->dbentry[ndx].deleted = 0;
        } else if (dbp != NULL)
                for (xdbp = TAILQ_FIRST(&logp->dbentry[ndx].dblist);
                    xdbp != NULL;
                    xdbp = TAILQ_NEXT(xdbp, links))
                        if (xdbp == dbp) {
                                TAILQ_REMOVE(&logp->dbentry[ndx].dblist,
                                    xdbp, links);
                                break;
                        }

        MUTEX_THREAD_UNLOCK(logp->mutexp);
}

/*
 * __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;
        int32_t lid;
        FNAME **fnamep;
{
        FNAME *fnp;
        LOG *lp;

        lp = dblp->reginfo.primary;

        for (fnp = SH_TAILQ_FIRST(&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);
}

---