libdb-sys 0.1.1

/*-
 * See the file LICENSE for redistribution information.
 *
 * Copyright (c) 2001, 2012 Oracle and/or its affiliates.  All rights reserved.
 *
 * $Id$
 */

#include "db_config.h"

#include "db_int.h"
#include "dbinc/db_page.h"
#include "dbinc/lock.h"
#include "dbinc/mp.h"
#include "dbinc/txn.h"
#include "dbinc/db_am.h"

typedef struct __txn_event TXN_EVENT;
struct __txn_event {
	TXN_EVENT_T op;
	TAILQ_ENTRY(__txn_event) links;
	union {
		struct {
			/* Delayed close. */
			DB *dbp;
		} c;
		struct {
			/* Delayed remove. */
			char *name;
			u_int8_t *fileid;
			int inmem;
		} r;
		struct {
			/* Lock event. */
			DB_LOCK lock;
			DB_LOCKER *locker;
			DB *dbp;
		} t;
	} u;
};

#define	TXN_TOP_PARENT(txn) do {					\
	while (txn->parent != NULL)					\
		txn = txn->parent;					\
} while (0)

static void __clear_fe_watermark __P((DB_TXN *, DB *));

/*
 * __txn_closeevent --
 *
 * Creates a close event that can be added to the [so-called] commit list, so
 * that we can redo a failed DB handle close once we've aborted the transaction.
 *
 * PUBLIC: int __txn_closeevent __P((ENV *, DB_TXN *, DB *));
 */
int
__txn_closeevent(env, txn, dbp)
	ENV *env;
	DB_TXN *txn;
	DB *dbp;
{
	int ret;
	TXN_EVENT *e;

	e = NULL;
	if ((ret = __os_calloc(env, 1, sizeof(TXN_EVENT), &e)) != 0)
		return (ret);

	e->u.c.dbp = dbp;
	e->op = TXN_CLOSE;
	TXN_TOP_PARENT(txn);
	TAILQ_INSERT_TAIL(&txn->events, e, links);

	return (0);
}

/*
 * __txn_remevent --
 *
 * Creates a remove event that can be added to the commit list.
 *
 * PUBLIC: int __txn_remevent __P((ENV *,
 * PUBLIC:       DB_TXN *, const char *, u_int8_t *, int));
 */
int
__txn_remevent(env, txn, name, fileid, inmem)
	ENV *env;
	DB_TXN *txn;
	const char *name;
	u_int8_t *fileid;
	int inmem;
{
	int ret;
	TXN_EVENT *e;

	e = NULL;
	if ((ret = __os_calloc(env, 1, sizeof(TXN_EVENT), &e)) != 0)
		return (ret);

	if ((ret = __os_strdup(env, name, &e->u.r.name)) != 0)
		goto err;

	if (fileid != NULL) {
		if ((ret = __os_calloc(env,
		    1, DB_FILE_ID_LEN, &e->u.r.fileid)) != 0) {
			__os_free(env, e->u.r.name);
			goto err;
		}
		memcpy(e->u.r.fileid, fileid, DB_FILE_ID_LEN);
	}

	e->u.r.inmem = inmem;
	e->op = TXN_REMOVE;
	TAILQ_INSERT_TAIL(&txn->events, e, links);

	return (0);

err:	__os_free(env, e);

	return (ret);
}

/*
 * __txn_remrem --
 *	Remove a remove event because the remove has been superceeded,
 * by a create of the same name, for example.
 *
 * PUBLIC: void __txn_remrem __P((ENV *, DB_TXN *, const char *));
 */
void
__txn_remrem(env, txn, name)
	ENV *env;
	DB_TXN *txn;
	const char *name;
{
	TXN_EVENT *e, *next_e;

	for (e = TAILQ_FIRST(&txn->events); e != NULL; e = next_e) {
		next_e = TAILQ_NEXT(e, links);
		if (e->op != TXN_REMOVE || strcmp(name, e->u.r.name) != 0)
			continue;
		TAILQ_REMOVE(&txn->events, e, links);
		__os_free(env, e->u.r.name);
		if (e->u.r.fileid != NULL)
			__os_free(env, e->u.r.fileid);
		__os_free(env, e);
	}

	return;
}

/*
 * __txn_lockevent --
 *
 * Add a lockevent to the commit-queue.  The lock event indicates a locker
 * trade.
 *
 * PUBLIC: int __txn_lockevent __P((ENV *,
 * PUBLIC:     DB_TXN *, DB *, DB_LOCK *, DB_LOCKER *));
 */
int
__txn_lockevent(env, txn, dbp, lock, locker)
	ENV *env;
	DB_TXN *txn;
	DB *dbp;
	DB_LOCK *lock;
	DB_LOCKER *locker;
{
	int ret;
	TXN_EVENT *e;

	if (!LOCKING_ON(env))
		return (0);

	e = NULL;
	if ((ret = __os_calloc(env, 1, sizeof(TXN_EVENT), &e)) != 0)
		return (ret);

	e->u.t.locker = locker;
	e->u.t.lock = *lock;
	e->u.t.dbp = dbp;
	if (F2_ISSET(dbp, DB2_AM_EXCL))
		e->op = TXN_XTRADE;
	else
		e->op = TXN_TRADE;
	/* This event goes on the current transaction, not its parent. */
	TAILQ_INSERT_TAIL(&txn->events, e, links);
	dbp->cur_txn = txn;

	return (0);
}

/*
 * __txn_remlock --
 *	Remove a lock event because the locker is going away.  We can remove
 * by lock (using offset) or by locker_id (or by both).
 *
 * PUBLIC: void __txn_remlock __P((ENV *, DB_TXN *, DB_LOCK *, DB_LOCKER *));
 */
void
__txn_remlock(env, txn, lock, locker)
	ENV *env;
	DB_TXN *txn;
	DB_LOCK *lock;
	DB_LOCKER *locker;
{
	TXN_EVENT *e, *next_e;

	for (e = TAILQ_FIRST(&txn->events); e != NULL; e = next_e) {
		next_e = TAILQ_NEXT(e, links);
		if ((e->op != TXN_TRADE && e->op != TXN_TRADED && 
		    e->op != TXN_XTRADE) ||
		    (e->u.t.lock.off != lock->off && e->u.t.locker != locker))
			continue;
		TAILQ_REMOVE(&txn->events, e, links);
		__os_free(env, e);
	}

	return;
}

/*
 * __txn_doevents --
 * Process the list of events associated with a transaction.  On commit,
 * apply the events; on abort, just toss the entries.
 *
 * PUBLIC: int __txn_doevents __P((ENV *, DB_TXN *, int, int));
 */

/*
 * Trade a locker associated with a thread for one that is associated
 * only with the handle. Mark the locker so failcheck will know.
 */
#define	DO_TRADE do {							\
	memset(&req, 0, sizeof(req));					\
	req.lock = e->u.t.lock;						\
	req.op = DB_LOCK_TRADE;						\
	t_ret = __lock_vec(env, txn->parent ?				\
	    txn->parent->locker : e->u.t.locker, 0, &req, 1, NULL);	\
	if (t_ret == 0)	{						\
		if (txn->parent != NULL) {				\
			e->u.t.dbp->cur_txn = txn->parent;		\
			e->u.t.dbp->cur_locker = txn->parent->locker;	\
		} else {						\
			e->op = TXN_TRADED;				\
			e->u.t.dbp->cur_locker = e->u.t.locker;		\
			F_SET(e->u.t.dbp->cur_locker,			\
			    DB_LOCKER_HANDLE_LOCKER);			\
			if (opcode != TXN_PREPARE)			\
				e->u.t.dbp->cur_txn = NULL;		\
		}							\
	} else if (t_ret == DB_NOTFOUND)				\
		t_ret = 0;						\
	if (t_ret != 0 && ret == 0)					\
		ret = t_ret;						\
} while (0)

int
__txn_doevents(env, txn, opcode, preprocess)
	ENV *env;
	DB_TXN *txn;
	int opcode, preprocess;
{
	DB_LOCKREQ req;
	TXN_EVENT *e, *enext;
	int ret, t_ret;

	ret = 0;

	/*
	 * This phase only gets called if we have a phase where we
	 * release read locks.  Since not all paths will call this
	 * phase, we have to check for it below as well.  So, when
	 * we do the trade, we update the opcode of the entry so that
	 * we don't try the trade again.
	 */
	if (preprocess) {
		for (e = TAILQ_FIRST(&txn->events);
		    e != NULL; e = enext) {
			enext = TAILQ_NEXT(e, links);
			/*
			 * Move all exclusive handle locks and 
			 * read handle locks to the handle locker.
			 */
			if (!(opcode == TXN_COMMIT && e->op == TXN_XTRADE) &&
			    (e->op != TXN_TRADE || 
			    IS_WRITELOCK(e->u.t.lock.mode)))
				continue;
			DO_TRADE;
			if (txn->parent != NULL) {
				TAILQ_REMOVE(&txn->events, e, links);
				TAILQ_INSERT_HEAD(
				     &txn->parent->events, e, links);
			}
		}
		return (ret);
	}

	/*
	 * Prepare should only cause a preprocess, since the transaction
	 * isn't over.
	 */
	DB_ASSERT(env, opcode != TXN_PREPARE);
	while ((e = TAILQ_FIRST(&txn->events)) != NULL) {
		TAILQ_REMOVE(&txn->events, e, links);
		/*
		 * Most deferred events should only happen on
		 * commits, not aborts or prepares.  The two exceptions are
		 * close and xtrade which gets done on commit and abort, but
		 * not prepare. If we're not doing operations, then we
		 * can just go free resources.
		 */
		if (opcode == TXN_ABORT && (e->op != TXN_CLOSE &&
		    e->op != TXN_XTRADE))
			goto dofree;
		switch (e->op) {
		case TXN_CLOSE:
			if ((t_ret = __db_close(e->u.c.dbp,
			    NULL, DB_NOSYNC)) != 0 && ret == 0)
				ret = t_ret;
			break;
		case TXN_REMOVE:
			if (txn->parent != NULL)
				TAILQ_INSERT_TAIL(
				    &txn->parent->events, e, links);
			else if (e->u.r.fileid != NULL) {
				if ((t_ret = __memp_nameop(env,
				    e->u.r.fileid, NULL, e->u.r.name,
				    NULL, e->u.r.inmem)) != 0 && ret == 0)
					ret = t_ret;
			} else if ((t_ret =
			    __os_unlink(env, e->u.r.name, 0)) != 0 && ret == 0)
				ret = t_ret;
			break;
		case TXN_TRADE:
		case TXN_XTRADE:
			DO_TRADE;
			if (txn->parent != NULL) {
				TAILQ_INSERT_HEAD(
				     &txn->parent->events, e, links);
				continue;
			}
			/* Fall through */
		case TXN_TRADED:
			/*
			 * Downgrade the lock if it is not an exclusive
			 * database handle lock.  An exclusive database
			 * should not have any locks other than the
			 * handle lock.
			 */
			if (ret == 0 && !F2_ISSET(e->u.t.dbp, DB2_AM_EXCL)) {
				if ((t_ret = __lock_downgrade(env,
				    &e->u.t.lock, DB_LOCK_READ, 0)) != 0 &&
				    ret == 0)
					ret = t_ret;
				/* Update the handle lock mode. */
				if (ret == 0 && e->u.t.lock.off ==
				    e->u.t.dbp->handle_lock.off &&
				    e->u.t.lock.ndx ==
				    e->u.t.dbp->handle_lock.ndx)
					e->u.t.dbp->handle_lock.mode =
					    DB_LOCK_READ;
			}
			break;
		default:
			/* This had better never happen. */
			DB_ASSERT(env, 0);
		}
dofree:
		/* Free resources here. */
		switch (e->op) {
		case TXN_REMOVE:
			if (txn->parent != NULL)
				continue;
			if (e->u.r.fileid != NULL)
				__os_free(env, e->u.r.fileid);
			__os_free(env, e->u.r.name);
			break;
		case TXN_TRADE:
		case TXN_XTRADE:
			if (opcode == TXN_ABORT)
				e->u.t.dbp->cur_txn = NULL;
			break;
		case TXN_CLOSE:
		case TXN_TRADED:
		default:
			break;
		}
		__os_free(env, e);
	}

	return (ret);
}

/*
 * PUBLIC: int __txn_record_fname __P((ENV *, DB_TXN *, FNAME *));
 */
int
__txn_record_fname(env, txn, fname)
	ENV *env;
	DB_TXN *txn;
	FNAME *fname;
{
	DB_LOG *dblp;
	DB_TXNMGR *mgr;
	TXN_DETAIL *td;
	roff_t fname_off;
	roff_t *np, *ldbs;
	u_int32_t i;
	int ret;

	if ((td = txn->td) == NULL)
		return (0);
	mgr = env->tx_handle;
	dblp = env->lg_handle;
	fname_off = R_OFFSET(&dblp->reginfo, fname);

	/* See if we already have a ref to this DB handle. */
	ldbs = R_ADDR(&mgr->reginfo, td->log_dbs);
	for (i = 0, np = ldbs; i < td->nlog_dbs; i++, np++)
		if (*np == fname_off)
			return (0);

	if (td->nlog_slots <= td->nlog_dbs) {
		TXN_SYSTEM_LOCK(env);
		if ((ret = __env_alloc(&mgr->reginfo,
		    sizeof(roff_t) * (td->nlog_slots << 1), &np)) != 0) {
			TXN_SYSTEM_UNLOCK(env);
			return (ret);
		}

		memcpy(np, ldbs, td->nlog_dbs * sizeof(roff_t));
		if (td->nlog_slots > TXN_NSLOTS)
			__env_alloc_free(&mgr->reginfo, ldbs);

		TXN_SYSTEM_UNLOCK(env);
		td->log_dbs = R_OFFSET(&mgr->reginfo, np);
		ldbs = np;
		td->nlog_slots = td->nlog_slots << 1;
	}

	ldbs[td->nlog_dbs] = fname_off;
	td->nlog_dbs++;
	fname->txn_ref++;

	return (0);
}

/*
 * __txn_dref_fnam --
 *	Either pass the fname to our parent txn or decrement the refcount
 * and close the fileid if it goes to zero.
 *
 * PUBLIC: int __txn_dref_fname __P((ENV *, DB_TXN *));
 */
int
__txn_dref_fname(env, txn)
	ENV *env;
	DB_TXN *txn;
{
	DB_LOG *dblp;
	DB_TXNMGR *mgr;
	FNAME *fname;
	roff_t *np;
	TXN_DETAIL *ptd, *td;
	u_int32_t i;
	int ret;

	td = txn->td;

	if (td->nlog_dbs == 0)
		return (0);

	mgr = env->tx_handle;
	dblp = env->lg_handle;
	ret = 0;

	ptd = txn->parent != NULL ? txn->parent->td : NULL;

	np = R_ADDR(&mgr->reginfo, td->log_dbs);
	/*
	 * The order in which FNAMEs are cleaned up matters.  Cleaning up
	 * in the wrong order can result in database handles leaking.  If
	 * we are passing the FNAMEs to the parent transaction make sure
	 * they are passed in order.  If we are cleaning up the FNAMEs,
	 * make sure that is done in reverse order.
	 */
	if (ptd != NULL) {
		for (i = 0; i < td->nlog_dbs; i++, np++) {
			fname = R_ADDR(&dblp->reginfo, *np);
			MUTEX_LOCK(env, fname->mutex);
			ret = __txn_record_fname(env, txn->parent, fname);
			fname->txn_ref--;
			MUTEX_UNLOCK(env, fname->mutex);
			if (ret != 0)
				break;
		}
	} else {
		np += td->nlog_dbs - 1;
		for (i = 0; i < td->nlog_dbs; i++, np--) {
			fname = R_ADDR(&dblp->reginfo, *np);
			MUTEX_LOCK(env, fname->mutex);
			if (fname->txn_ref == 1) {
				MUTEX_UNLOCK(env, fname->mutex);
				DB_ASSERT(env, fname->txn_ref != 0);
				ret = __dbreg_close_id_int(
				    env, fname, DBREG_CLOSE, 0);
			} else {
				fname->txn_ref--;
				MUTEX_UNLOCK(env, fname->mutex);
			}
			if (ret != 0 && ret != EIO)
				break;
		}
	}

	return (ret);
}

/*
 * Common removal routine.  This is called only after verifying that
 * the DB_MPOOLFILE is in the list.
 */
static void
__clear_fe_watermark(txn, db)
     DB_TXN *txn;
     DB *db;
{
	MPOOLFILE *mpf;

	mpf = db->mpf->mfp;
	mpf->fe_watermark = PGNO_INVALID;
	mpf->fe_txnid = 0U;
	mpf->fe_nlws = 0U;
	TAILQ_REMOVE(&txn->femfs, db, felink);
}

/*
 * __txn_reset_fe_watermarks
 * Reset the file extension state of MPOOLFILEs involved in this transaction.
 *
 * PUBLIC: void __txn_reset_fe_watermarks __P((DB_TXN *));
 */
void
__txn_reset_fe_watermarks(txn)
     DB_TXN *txn;
{
	DB *db;

	if (txn->parent) {
		DB_ASSERT(txn->mgrp->env, TAILQ_FIRST(&txn->femfs) == NULL);
	}

	while ((db = TAILQ_FIRST(&txn->femfs)))
		__clear_fe_watermark(txn, db);
}

/*
 * __txn_remove_fe_watermark
 * Remove a watermark from the transaction's list
 *
 * PUBLIC: void __txn_remove_fe_watermark __P((DB_TXN *,DB *));
 */
void
__txn_remove_fe_watermark(txn, db)
     DB_TXN *txn;
     DB *db;
{
	DB *db_tmp;

	if (txn == NULL || !F_ISSET(txn, TXN_BULK))
		return;

	TAILQ_FOREACH(db_tmp, &txn->femfs, felink) {
		if (db_tmp == db) {
			__clear_fe_watermark(txn, db);
			break;
		}
	}
}

/*
 * __txn_add_fe_watermark
 *
 * Add an entry to the transaction's list of
 * file_extension_watermarks, if warranted.  Also, set the watermark
 * page number in the MPOOLFILE.  The metadata lock associated with
 * the mfp must be held when this function is called.
 *
 * PUBLIC: void __txn_add_fe_watermark __P((DB_TXN *, DB *, db_pgno_t));
 */
void
__txn_add_fe_watermark(txn, db, pgno)
     DB_TXN *txn;
     DB *db;
     db_pgno_t pgno;
{
	MPOOLFILE *mfp;

	if (txn == NULL || !F_ISSET(txn, TXN_BULK))
		return;

	mfp = db->mpf->mfp;
	/* If the watermark is already set, there's nothing to do. */
	if (mfp->fe_watermark != PGNO_INVALID) {
#ifdef DIAGNOSTIC
		DB_ASSERT(txn->mgrp->env, mfp->fe_txnid == txn->txnid);
#endif
		return;
	}

	/* We can update MPOOLFILE because the metadata lock is held. */
	mfp->fe_watermark = pgno;
	mfp->fe_txnid = txn->txnid;

	TAILQ_INSERT_TAIL(&txn->femfs, db, felink);
}

/*
 * __txn_flush_fe_files
 * For every extended file in which a log record write was skipped,
 * flush the data pages.  This is called during commit.
 *
 * PUBLIC: int __txn_flush_fe_files __P((DB_TXN *));
 */
int
__txn_flush_fe_files(txn)
     DB_TXN *txn;
{
	DB *db;
	ENV *env;
	int ret;

	env = txn->mgrp->env;

	DB_ASSERT(env, txn->mgrp != NULL);
	DB_ASSERT(env, env != NULL);

#ifdef DIAGNOSTIC
	DB_ASSERT(env, txn->parent == NULL);
#endif

	TAILQ_FOREACH(db, &txn->femfs, felink) {
		if (db->mpf->mfp->fe_nlws > 0 &&
		    (ret = __memp_sync_int(env, db->mpf, 0,
		    DB_SYNC_FILE, NULL, NULL)))
			return (ret);
	}

	return (0);
}

/*
 * __txn_pg_above_fe_watermark --
 *
 * Test whether there is a file extension watermark for the given
 * database, and, if so, whether the given page number is above the
 * watermark.  If this test returns true, then logging of the page's
 * update can be suppressed when the file extension/bulk loading
 * optimization is in force.
 *
 * PUBLIC: int __txn_pg_above_fe_watermark
 * PUBLIC:	__P((DB_TXN*, MPOOLFILE*, db_pgno_t));
 */
int
__txn_pg_above_fe_watermark(txn, mpf, pgno)
     DB_TXN *txn;
     MPOOLFILE *mpf;
     db_pgno_t pgno;
{
	ENV *env;
	int skip;

	if (txn == NULL || (!F_ISSET(txn, TXN_BULK)) ||
	    mpf->fe_watermark == PGNO_INVALID)
		return (0);

	env = txn->mgrp->env;

	skip = 0;
	TXN_SYSTEM_LOCK(env);
	if (((DB_TXNREGION *)env->tx_handle->reginfo.primary)->n_hotbackup > 0)
		skip = 1;
	TXN_SYSTEM_UNLOCK(env);
	if (skip)
		return (0);

	/*
	 * If the watermark is a valid page number, then the extending
	 * transaction should be the current outermost transaction.
	 */
	DB_ASSERT(txn->mgrp->env, mpf->fe_txnid == txn->txnid);

	return (mpf->fe_watermark <= pgno);
}