/*- * See the file LICENSE for redistribution information. * * Copyright (c) 1996-2001 * Sleepycat Software. All rights reserved. */ /* * Copyright (c) 1995, 1996 * The President and Fellows of Harvard University. All rights reserved. * * This code is derived from software contributed to Berkeley by * Margo Seltzer. * * 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 "db_config.h" #ifndef lint static const char revid[] = "$Id: txn.c,v 11.125 2001/11/16 16:28:17 bostic Exp $"; #endif /* not lint */ #ifndef NO_SYSTEM_INCLUDES #include #if TIME_WITH_SYS_TIME #include #include #else #if HAVE_SYS_TIME_H #include #else #include #endif #endif #include #endif #include "db_int.h" #include "db_page.h" #include "db_shash.h" #include "hash.h" #include "lock.h" #include "log.h" #include "txn.h" /* * __txn_isvalid enumerated types. We cannot simply use the transaction * statuses, because different statuses need to be handled differently * depending on the caller. */ typedef enum { TXN_OP_ABORT, TXN_OP_COMMIT, TXN_OP_DISCARD, TXN_OP_PREPARE } txnop_t; static int __txn_begin_int __P((DB_TXN *, int)); static void __txn_end __P((DB_TXN *, int)); static int __txn_isvalid __P((const DB_TXN *, TXN_DETAIL **, txnop_t)); static int __txn_set_timeout __P(( DB_TXN *, db_timeout_t, u_int32_t)); static int __txn_undo __P((DB_TXN *)); #ifndef db_create /* * txn_abort -- * txn_begin -- * txn_commit -- * * When we switched to methods in 4.0, we guessed txn_{abort,begin,commit} * were the interfaces applications would likely use and not be willing to * change, due to the sheer volume of the calls. Provide wrappers -- we * could do txn_abort and txn_commit using macros, but not txn_begin, as * the name of the field is txn_begin, we didn't want to modify it. * * The issue with txn_begin hits us in another way. If configured with the * --with-uniquename option, we use #defines to re-define DB's interfaces * to unique names. We can't do that for these functions because txn_begin * is also a field name in the DB_ENV structure, and the #defines we use go * at the end of the db.h file -- we get control too late to #define a field * name. So, modify the script that generates the unique names #defines to * not generate them for these three functions, and don't include the three * functions in libraries built with that configuration option. * * EXTERN: int txn_abort __P((DB_TXN *)); * EXTERN: int txn_begin __P((DB_ENV *, DB_TXN *, DB_TXN **, u_int32_t)); * EXTERN: int txn_commit __P((DB_TXN *, u_int32_t)); */ int txn_abort(txnp) DB_TXN *txnp; { return (txnp->abort(txnp)); } int txn_begin(dbenv, parent, txnpp, flags) DB_ENV *dbenv; DB_TXN *parent, **txnpp; u_int32_t flags; { return (dbenv->txn_begin(dbenv, parent, txnpp, flags)); } int txn_commit(txnp, flags) DB_TXN *txnp; u_int32_t flags; { return (txnp->commit(txnp, flags)); } #endif /* !db_create */ /* * __txn_begin -- * This is a wrapper to the actual begin process. Normal transaction * begin allocates a DB_TXN structure for the caller, while XA transaction * begin does not. Other than that, both call into common __txn_begin_int * code. * * Internally, we use TXN_DETAIL structures, but the DB_TXN structure * provides access to the transaction ID and the offset in the transaction * region of the TXN_DETAIL structure. * * PUBLIC: int __txn_begin __P((DB_ENV *, DB_TXN *, DB_TXN **, u_int32_t)); */ int __txn_begin(dbenv, parent, txnpp, flags) DB_ENV *dbenv; DB_TXN *parent, **txnpp; u_int32_t flags; { DB_LOCKREGION *region; DB_TXN *txn; int ret; *txnpp = NULL; PANIC_CHECK(dbenv); ENV_REQUIRES_CONFIG(dbenv, dbenv->tx_handle, "txn_begin", DB_INIT_TXN); if ((ret = __db_fchk(dbenv, "txn_begin", flags, DB_DIRTY_READ | DB_TXN_NOWAIT | DB_TXN_NOSYNC | DB_TXN_SYNC)) != 0) return (ret); if ((ret = __db_fcchk(dbenv, "txn_begin", flags, DB_TXN_NOSYNC, DB_TXN_SYNC)) != 0) return (ret); if ((ret = __os_calloc(dbenv, 1, sizeof(DB_TXN), &txn)) != 0) return (ret); txn->mgrp = dbenv->tx_handle; txn->parent = parent; TAILQ_INIT(&txn->kids); txn->flags = TXN_MALLOC; if (LF_ISSET(DB_DIRTY_READ)) F_SET(txn, TXN_DIRTY_READ); if (LF_ISSET(DB_TXN_NOSYNC)) F_SET(txn, TXN_NOSYNC); if (LF_ISSET(DB_TXN_SYNC)) F_SET(txn, TXN_SYNC); if (LF_ISSET(DB_TXN_NOWAIT)) F_SET(txn, TXN_NOWAIT); if ((ret = __txn_begin_int(txn, 0)) != 0) goto err; if (parent != NULL) TAILQ_INSERT_HEAD(&parent->kids, txn, klinks); if (LOCKING_ON(dbenv)) { region = ((DB_LOCKTAB *)dbenv->lk_handle)->reginfo.primary; if (parent != NULL) { ret = __lock_inherit_timeout(dbenv, parent->txnid, txn->txnid); /* No parent locker set yet. */ if (ret == EINVAL) { parent = NULL; ret = 0; } if (ret != 0) goto err; } /* * Parent is NULL if we have no parent * or it has no timeouts set. */ if (parent == NULL && region->tx_timeout != 0) if ((ret = __lock_set_timeout(dbenv, txn->txnid, region->tx_timeout, DB_SET_TXN_TIMEOUT)) != 0) goto err; } *txnpp = txn; return (0); err: __os_free(dbenv, txn, sizeof(DB_TXN)); return (ret); } /* * __txn_xa_begin -- * XA version of txn_begin. * * PUBLIC: int __txn_xa_begin __P((DB_ENV *, DB_TXN *)); */ int __txn_xa_begin(dbenv, txn) DB_ENV *dbenv; DB_TXN *txn; { PANIC_CHECK(dbenv); memset(txn, 0, sizeof(DB_TXN)); txn->mgrp = dbenv->tx_handle; return (__txn_begin_int(txn, 0)); } /* * __txn_compensate_begin * Begin an compensation transaction. This is a special interface * that is used only for transactions that must be started to compensate * for actions during an abort. Currently only used for allocations. * * PUBLIC: int __txn_compensate_begin __P((DB_ENV *, DB_TXN **txnp)); */ int __txn_compensate_begin(dbenv, txnpp) DB_ENV *dbenv; DB_TXN **txnpp; { DB_TXN *txn; int ret; PANIC_CHECK(dbenv); if ((ret = __os_calloc(dbenv, 1, sizeof(DB_TXN), &txn)) != 0) return (ret); txn->mgrp = dbenv->tx_handle; *txnpp = txn; F_SET(txn, TXN_COMPENSATE); return (__txn_begin_int(txn, 1)); } /* * __txn_begin_int -- * Normal DB version of txn_begin. */ static int __txn_begin_int(txn, internal) DB_TXN *txn; int internal; { DB_ENV *dbenv; DB_LSN begin_lsn; DB_TXNMGR *mgr; DB_TXNREGION *region; TXN_DETAIL *td; size_t off; u_int32_t id, min_inuse; int ret; mgr = txn->mgrp; dbenv = mgr->dbenv; region = mgr->reginfo.primary; /* * We do not have to write begin records (and if we do not, then we * need never write records for read-only transactions). However, * we do need to find the current LSN so that we can store it in the * transaction structure, so we can know where to take checkpoints. */ if (LOGGING_ON(dbenv) && (ret = dbenv->log_put(dbenv, &begin_lsn, NULL, DB_CURLSN)) != 0) goto err2; R_LOCK(dbenv, &mgr->reginfo); if (!F_ISSET(txn, TXN_COMPENSATE) && F_ISSET(region, TXN_IN_RECOVERY)) { __db_err(dbenv, "operation not permitted during recovery."); ret = EINVAL; goto err1; } /* Make sure that we aren't still recovering prepared transactions. */ if (!internal && region->stat.st_nrestores != 0) { __db_err(dbenv, "txn_begin: recovery of prepared but not yet committed transactions is incomplete."); ret = EINVAL; goto err1; } /* * Allocate a new transaction id. If we wrap around then we * find the minimum currently in use and make sure we * can stay below that. This code is similar to code * in __lock_id for recovering locker ids. */ if (region->last_txnid == region->cur_maxid) { min_inuse = TXN_INVALID; /* If cur_maxid is at the top we are wrapping around. */ if (region->cur_maxid == TXN_INVALID) region->cur_maxid = TXN_MINIMUM; /* * Traverse teh active transactions and find the * lowest txnid which is in use. */ for (td = SH_TAILQ_FIRST(®ion->active_txn, __txn_detail); td != NULL; td = SH_TAILQ_NEXT(td, links, __txn_detail)) { if (td->txnid > region->cur_maxid && td->txnid < min_inuse) min_inuse = td->txnid; } /* Set the maxid to the new lowest. */ region->cur_maxid = min_inuse; /* * Check to see if the current txnid is wrapping around. * Since this should represent the last id allocated * and we don't use TXN_MINIMUM things are * a little tricky, we don't want to allocate * the first id if its inuse. */ if (region->last_txnid == TXN_INVALID) { if (min_inuse == TXN_MINIMUM + 1) region->last_txnid = min_inuse; else region->last_txnid = TXN_MINIMUM; } /* See if we fixed the situation. */ if (region->last_txnid == region->cur_maxid) { __db_err(dbenv, "txn_begin: transaction ID wrapped. Exit the database environment\nand restart the application as if application failure had occurred"); ret = EINVAL; goto err1; } } /* Allocate a new transaction detail structure. */ if ((ret = __db_shalloc(mgr->reginfo.addr, sizeof(TXN_DETAIL), 0, &td)) != 0) { __db_err(dbenv, "Unable to allocate memory for transaction detail"); goto err1; } /* Place transaction on active transaction list. */ SH_TAILQ_INSERT_HEAD(®ion->active_txn, td, links, __txn_detail); id = ++region->last_txnid; ++region->stat.st_nbegins; if (++region->stat.st_nactive > region->stat.st_maxnactive) region->stat.st_maxnactive = region->stat.st_nactive; td->txnid = id; td->begin_lsn = begin_lsn; ZERO_LSN(td->last_lsn); td->status = TXN_RUNNING; if (txn->parent != NULL) td->parent = txn->parent->off; else td->parent = INVALID_ROFF; td->flags = 0; off = R_OFFSET(&mgr->reginfo, td); R_UNLOCK(dbenv, &mgr->reginfo); ZERO_LSN(txn->last_lsn); txn->txnid = id; txn->off = off; txn->abort = __txn_abort; txn->commit = __txn_commit; txn->discard = __txn_discard; txn->id = __txn_id; txn->prepare = __txn_prepare; txn->set_timeout = __txn_set_timeout; /* * If this is a transaction family, we must link the child to the * maximal grandparent in the lock table for deadlock detection. */ if (txn->parent != NULL && LOCKING_ON(dbenv)) if ((ret = __lock_addfamilylocker(dbenv, txn->parent->txnid, txn->txnid)) != 0) goto err2; if (F_ISSET(txn, TXN_MALLOC)) { MUTEX_THREAD_LOCK(dbenv, mgr->mutexp); TAILQ_INSERT_TAIL(&mgr->txn_chain, txn, links); MUTEX_THREAD_UNLOCK(dbenv, mgr->mutexp); } return (0); err1: R_UNLOCK(dbenv, &mgr->reginfo); err2: return (ret); } /* * __txn_commit -- * Commit a transaction. * * PUBLIC: int __txn_commit __P((DB_TXN *, u_int32_t)); */ int __txn_commit(txnp, flags) DB_TXN *txnp; u_int32_t flags; { DB_ENV *dbenv; DB_LOCKREQ request; DB_TXN *kid; int ret; dbenv = txnp->mgrp->dbenv; PANIC_CHECK(dbenv); if ((ret = __txn_isvalid(txnp, NULL, TXN_OP_COMMIT)) != 0) return (ret); /* * We clear flags that are incorrect, ignoring any flag errors, and * default to synchronous operations. By definition, transaction * handles are dead when we return, and this error should never * happen, but we don't want to fail in the field 'cause the app is * specifying the wrong flag for some reason. */ if (__db_fchk(dbenv, "DB_TXN->commit", flags, DB_TXN_NOSYNC | DB_TXN_SYNC) != 0) flags = DB_TXN_SYNC; if (__db_fcchk(dbenv, "DB_TXN->commit", flags, DB_TXN_NOSYNC, DB_TXN_SYNC) != 0) flags = DB_TXN_SYNC; if (LF_ISSET(DB_TXN_NOSYNC)) { F_CLR(txnp, TXN_SYNC); F_SET(txnp, TXN_NOSYNC); } if (LF_ISSET(DB_TXN_SYNC)) { F_CLR(txnp, TXN_NOSYNC); F_SET(txnp, TXN_SYNC); } /* * Commit any unresolved children. If there's an error, abort any * unresolved children and the parent. */ while ((kid = TAILQ_FIRST(&txnp->kids)) != NULL) if ((ret = kid->commit(kid, flags)) != 0) { while ((kid = TAILQ_FIRST(&txnp->kids)) != NULL) (void)kid->abort(kid); goto err; } /* * If there are any log records, write a log record and sync the log, * else do no log writes. If the commit is for a child transaction, * we do not need to commit the child synchronously since it may still * abort (if its parent aborts), and otherwise its parent or ultimate * ancestor will write synchronously. */ if (LOGGING_ON(dbenv) && !IS_ZERO_LSN(txnp->last_lsn)) { if (txnp->parent == NULL) { request.op = DB_LOCK_PUT_READ; if (LOCKING_ON(dbenv) && (ret = dbenv->lock_vec( dbenv, txnp->txnid, 0, &request, 1, NULL)) != 0) goto err; if ((ret = __txn_regop_log(dbenv, txnp, &txnp->last_lsn, DB_COMMIT | ((F_ISSET(dbenv, DB_ENV_TXN_NOSYNC) && !F_ISSET(txnp, TXN_SYNC)) || F_ISSET(txnp, TXN_NOSYNC) ? 0 : DB_FLUSH), TXN_COMMIT, (int32_t)time(NULL))) != 0) goto err; } else { /* Log the commit in the parent! */ if ((ret = __txn_child_log(dbenv, txnp->parent, &txnp->parent->last_lsn, 0, txnp->txnid, &txnp->last_lsn)) != 0) { goto err; } F_SET(txnp->parent, TXN_CHILDCOMMIT); } } __txn_end(txnp, 1); return (0); err: (void)txnp->abort(txnp); return (ret); } /* * __txn_abort -- * Abort a transaction. * * PUBLIC: int __txn_abort __P((DB_TXN *)); */ int __txn_abort(txnp) DB_TXN *txnp; { DB_ENV *dbenv; DB_LOCKREQ request; DB_TXN *kid; TXN_DETAIL *td; int ret, t_ret; dbenv = txnp->mgrp->dbenv; PANIC_CHECK(dbenv); if ((ret = __txn_isvalid(txnp, &td, TXN_OP_ABORT)) != 0) return (ret); /* Abort any unresolved children. */ while ((kid = TAILQ_FIRST(&txnp->kids)) != NULL) if ((t_ret = kid->abort(kid)) != 0 && ret == 0) ret = t_ret; if (LOCKING_ON(dbenv)) { /* Turn off timeouts. */ if ((t_ret = __lock_set_timeout(dbenv, txnp->txnid, 0, DB_SET_TXN_TIMEOUT)) != 0 && ret == 0) ret = t_ret; if ((t_ret = __lock_set_timeout(dbenv, txnp->txnid, 0, DB_SET_LOCK_TIMEOUT)) != 0 && ret == 0) ret = t_ret; request.op = DB_LOCK_UPGRADE_WRITE; if ((ret = dbenv->lock_vec( dbenv, txnp->txnid, 0, &request, 1, NULL)) != 0) (void)__db_panic(dbenv, ret); } if ((t_ret = __txn_undo(txnp)) != 0 && ret == 0) ret = t_ret; /* * Normally, we do not need to log aborts. However, if we * are a distributed transaction (i.e., we have a prepare), * then we log the abort so we know that this transaction * was actually completed. Even if the log fails; abort/undo * the transaction. */ if (LOGGING_ON(dbenv) && td->status == TXN_PREPARED && (t_ret = __txn_regop_log(dbenv, txnp, &txnp->last_lsn, (F_ISSET(dbenv, DB_ENV_TXN_NOSYNC) && !F_ISSET(txnp, TXN_SYNC)) || F_ISSET(txnp, TXN_NOSYNC) ? 0 : DB_FLUSH, TXN_ABORT, (int32_t)time(NULL))) != 0 && ret == 0) ret = t_ret; __txn_end(txnp, 0); return (ret); } /* * __txn_discard -- * Free the per-process resources associated with this txn handle. * * PUBLIC: int __txn_discard __P((DB_TXN *, u_int32_t flags)); */ int __txn_discard(txnp, flags) DB_TXN *txnp; u_int32_t flags; { DB_ENV *dbenv; DB_TXN *freep; TXN_DETAIL *td; int ret; COMPQUIET(flags, 0); dbenv = txnp->mgrp->dbenv; freep = NULL; PANIC_CHECK(dbenv); if ((ret = __txn_isvalid(txnp, &td, TXN_OP_DISCARD)) != 0) return (ret); /* Should be no children. */ DB_ASSERT(TAILQ_FIRST(&txnp->kids) == NULL); DB_ASSERT(F_ISSET(td, TXN_RESTORED)); /* Free the space. */ MUTEX_THREAD_LOCK(dbenv, txnp->mgrp->mutexp); txnp->mgrp->n_discards++; if (F_ISSET(txnp, TXN_MALLOC)) { TAILQ_REMOVE(&txnp->mgrp->txn_chain, txnp, links); freep = txnp; } MUTEX_THREAD_UNLOCK(dbenv, txnp->mgrp->mutexp); if (freep != NULL) __os_free(dbenv, freep, sizeof(*freep)); return (ret); } /* * __txn_prepare -- * Flush the log so a future commit is guaranteed to succeed. * * PUBLIC: int __txn_prepare __P((DB_TXN *, u_int8_t *)); */ int __txn_prepare(txnp, gid) DB_TXN *txnp; u_int8_t *gid; { DBT xid; DB_ENV *dbenv; DB_TXN *kid; TXN_DETAIL *td; int ret; dbenv = txnp->mgrp->dbenv; PANIC_CHECK(dbenv); if ((ret = __txn_isvalid(txnp, &td, TXN_OP_PREPARE)) != 0) return (ret); if (txnp->parent != NULL) { __db_err(dbenv, "Prepare disallowed on child transactions."); return (EINVAL); } /* Commit any unresolved children. */ while ((kid = TAILQ_FIRST(&txnp->kids)) != NULL) if ((ret = kid->commit(kid, DB_TXN_NOSYNC)) != 0) return (ret); /* * In XA, the global transaction ID in the txn_detail structure is * already set; in a non-XA environment, we must set it here. XA * requires that the transaction be either ENDED or SUSPENDED when * prepare is called, so we know that if the xa_status isn't in one * of those states, then we are calling prepare directly and we need * to fill in the td->xid. */ if (LOGGING_ON(dbenv)) { memset(&xid, 0, sizeof(xid)); if (td->xa_status != TXN_XA_ENDED && td->xa_status != TXN_XA_SUSPENDED) /* Regular prepare; fill in the gid. */ memcpy(td->xid, gid, sizeof(td->xid)); xid.size = sizeof(td->xid); xid.data = td->xid; if ((ret = __txn_xa_regop_log(dbenv, txnp, &txnp->last_lsn, DB_COMMIT | ((F_ISSET(dbenv, DB_ENV_TXN_NOSYNC) && !F_ISSET(txnp, TXN_SYNC)) || F_ISSET(txnp, TXN_NOSYNC) ? 0 : DB_FLUSH), TXN_PREPARE, &xid, td->format, td->gtrid, td->bqual, &td->begin_lsn)) != 0) { __db_err(dbenv, "DB_TXN->prepare: log_write failed %s", db_strerror(ret)); return (ret); } } MUTEX_THREAD_LOCK(dbenv, txnp->mgrp->mutexp); td->status = TXN_PREPARED; MUTEX_THREAD_UNLOCK(dbenv, txnp->mgrp->mutexp); return (0); } /* * __txn_id -- * Return the transaction ID. * * PUBLIC: u_int32_t __txn_id __P((DB_TXN *)); */ u_int32_t __txn_id(txnp) DB_TXN *txnp; { return (txnp->txnid); } /* * __txn_set_timeout -- * Set timeout values in the txn structure. */ static int __txn_set_timeout(txnp, timeout, op) DB_TXN *txnp; db_timeout_t timeout; u_int32_t op; { if (op != DB_SET_TXN_TIMEOUT && op != DB_SET_LOCK_TIMEOUT) return (__db_ferr(txnp->mgrp->dbenv, "DB_TXN->set_timeout", 0)); return (__lock_set_timeout( txnp->mgrp->dbenv, txnp->txnid, timeout, op)); } /* * __txn_isvalid -- * Return 0 if the txnp is reasonable, otherwise panic. */ static int __txn_isvalid(txnp, tdp, op) const DB_TXN *txnp; TXN_DETAIL **tdp; txnop_t op; { DB_TXNMGR *mgrp; DB_TXNREGION *region; TXN_DETAIL *tp; mgrp = txnp->mgrp; region = mgrp->reginfo.primary; /* Check for recovery. */ if (!F_ISSET(txnp, TXN_COMPENSATE) && F_ISSET(region, TXN_IN_RECOVERY)) { __db_err(mgrp->dbenv, "operation not permitted during recovery."); goto err; } /* Check for live cursors. */ if (txnp->cursors != 0) { __db_err(mgrp->dbenv, "transaction has active cursors"); goto err; } /* Check transaction's state. */ tp = (TXN_DETAIL *)R_ADDR(&mgrp->reginfo, txnp->off); if (tdp != NULL) *tdp = tp; /* * Discard is a special case since we're just tossing the * per-process space; there are a lot of problems with the * transaction that we can tolerate. */ if (op == TXN_OP_DISCARD) { /* Transaction is already been reused. */ if (txnp->txnid != tp->txnid) return (0); /* * We have the right transaction, we'd better be * a restored transaction. However, if it's not, * we won't panic the environment since it means * that someone has a bad user-handle, not that the * transaction is corrupt. */ if (!F_ISSET(tp, TXN_RESTORED)) { __db_err(mgrp->dbenv, "not a restored transaction"); return (EINVAL); } /* * No matter what state the transaction is in, we can * blow away this process' handle. */ return (0); } switch (tp->status) { case TXN_ABORTED: case TXN_COMMITTED: default: __db_err(mgrp->dbenv, "transaction already %s", tp->status == TXN_COMMITTED ? "committed" : "aborted"); goto err; case TXN_PREPARED: if (op == TXN_OP_PREPARE) { __db_err(mgrp->dbenv, "transaction already prepared"); /* * Txn_prepare doesn't blow away the user handle, so * in this case, give the user the opportunity to * abort or commit. */ return (EINVAL); } break; case TXN_RUNNING: break; } return (0); err: /* * If there's a serious problem with the transaction, panic. TXN * handles are dead by definition when we return, and if you use * a cursor you forgot to close, we have no idea what will happen. */ return (__db_panic(mgrp->dbenv, EINVAL)); } /* * __txn_end -- * Internal transaction end routine. */ static void __txn_end(txnp, is_commit) DB_TXN *txnp; int is_commit; { DB_ENV *dbenv; DB_LOCKREQ request; DB_TXNMGR *mgr; DB_TXNREGION *region; TXN_DETAIL *tp; int do_closefiles, ret; mgr = txnp->mgrp; dbenv = mgr->dbenv; region = mgr->reginfo.primary; do_closefiles = 0; /* Release the locks. */ request.op = txnp->parent == NULL || is_commit == 0 ? DB_LOCK_PUT_ALL : DB_LOCK_INHERIT; /* * __txn_end cannot return an error, we MUST return success/failure * from commit or abort, ignoring any internal errors. So, we panic * if something goes wrong. We can't deadlock here because we're not * acquiring any new locks, so DB_LOCK_DEADLOCK is just as fatal as * any other error. */ if (LOCKING_ON(dbenv) && (ret = dbenv->lock_vec( dbenv, txnp->txnid, DB_LOCK_FREE_LOCKER, &request, 1, NULL)) != 0) (void)__db_panic(dbenv, ret); /* End the transaction. */ R_LOCK(dbenv, &mgr->reginfo); tp = (TXN_DETAIL *)R_ADDR(&mgr->reginfo, txnp->off); SH_TAILQ_REMOVE(®ion->active_txn, tp, links, __txn_detail); if (F_ISSET(tp, TXN_RESTORED)) { region->stat.st_nrestores--; do_closefiles = region->stat.st_nrestores == 0; } __db_shalloc_free(mgr->reginfo.addr, tp); if (is_commit) region->stat.st_ncommits++; else region->stat.st_naborts++; --region->stat.st_nactive; R_UNLOCK(dbenv, &mgr->reginfo); /* * The transaction cannot get more locks, remove its locker info, * if any. */ if (LOCKING_ON(dbenv) && (ret = __lock_freefamilylocker(dbenv->lk_handle, txnp->txnid)) != 0) (void)__db_panic(dbenv, ret); if (txnp->parent != NULL) TAILQ_REMOVE(&txnp->parent->kids, txnp, klinks); /* Free the space. */ if (F_ISSET(txnp, TXN_MALLOC)) { MUTEX_THREAD_LOCK(dbenv, mgr->mutexp); TAILQ_REMOVE(&mgr->txn_chain, txnp, links); MUTEX_THREAD_UNLOCK(dbenv, mgr->mutexp); __os_free(dbenv, txnp, sizeof(*txnp)); } if (do_closefiles) { F_SET((DB_LOG *)dbenv->lg_handle, DBLOG_RECOVER); __log_close_files(dbenv); F_CLR((DB_LOG *)dbenv->lg_handle, DBLOG_RECOVER); mgr->n_discards = 0; (void)dbenv->txn_checkpoint(dbenv, 0, 0, DB_FORCE); } } /* * __txn_undo -- * Undo the transaction with id txnid. Returns 0 on success and * errno on failure. */ static int __txn_undo(txnp) DB_TXN *txnp; { DBT rdbt; DB_ENV *dbenv; DB_LOGC *logc; DB_LSN key_lsn; DB_TXNMGR *mgr; int ret, t_ret, threaded; void *txnlist; mgr = txnp->mgrp; dbenv = mgr->dbenv; logc = NULL; txnlist = NULL; if (!LOGGING_ON(dbenv)) return (0); /* * This is the simplest way to code this, but if the mallocs during * recovery turn out to be a performance issue, we can do the * allocation here and use DB_DBT_USERMEM. */ memset(&rdbt, 0, sizeof(rdbt)); threaded = F_ISSET(dbenv, DB_ENV_THREAD) ? 1 : 0; if (threaded) F_SET(&rdbt, DB_DBT_MALLOC); key_lsn = txnp->last_lsn; /* Allocate a transaction list for children or aborted page creates. */ if ((ret = __db_txnlist_init(dbenv, 0, 0, &txnlist)) != 0) return (ret); if (F_ISSET(txnp, TXN_CHILDCOMMIT) && (ret = __db_txnlist_lsninit(dbenv, txnlist, &txnp->last_lsn)) != 0) return (ret); if ((ret = dbenv->log_cursor(dbenv, &logc, 0)) != 0) goto err; while (ret == 0 && !IS_ZERO_LSN(key_lsn)) { /* * The dispatch routine returns the lsn of the record * before the current one in the key_lsn argument. */ if ((ret = logc->get(logc, &key_lsn, &rdbt, DB_SET)) == 0) { ret = __db_dispatch(dbenv, NULL, &rdbt, &key_lsn, DB_TXN_ABORT, txnlist); if (threaded && rdbt.data != NULL) { __os_free(dbenv, rdbt.data, rdbt.size); rdbt.data = NULL; } if (F_ISSET(txnp, TXN_CHILDCOMMIT)) (void)__db_txnlist_lsnadd(dbenv, txnlist, &key_lsn, 0); } if (ret == DB_SURPRISE_KID) { if ((ret = __db_txnlist_lsninit( dbenv, txnlist, &key_lsn)) == 0) F_SET(txnp, TXN_CHILDCOMMIT); } else if (ret != 0) { __db_err(txnp->mgrp->dbenv, "DB_TXN->abort: Log undo failed for LSN: %lu %lu: %s", (u_long)key_lsn.file, (u_long)key_lsn.offset, db_strerror(ret)); goto err; } } if (txnlist != NULL) ret = __db_do_the_limbo(dbenv, txnlist); err: if (logc != NULL && (t_ret = logc->close(logc, 0)) != 0 && ret == 0) ret = t_ret; if (txnlist != NULL) __db_txnlist_end(dbenv, txnlist); return (ret); } /* * Transaction checkpoint. * If either kbytes or minutes is non-zero, then we only take the checkpoint * more than "minutes" minutes have passed since the last checkpoint or if * more than "kbytes" of log data have been written since the last checkpoint. * When taking a checkpoint, find the oldest active transaction and figure out * its first LSN. This is the lowest LSN we can checkpoint, since any record * written after since that point may be involved in a transaction and may * therefore need to be undone in the case of an abort. * * PUBLIC: int __txn_checkpoint * PUBLIC: __P((DB_ENV *, u_int32_t, u_int32_t, u_int32_t)); */ int __txn_checkpoint(dbenv, kbytes, minutes, flags) DB_ENV *dbenv; u_int32_t kbytes, minutes, flags; { DB_LOG *dblp; DB_LSN ckp_lsn, sync_lsn, last_ckp; DB_TXNMGR *mgr; DB_TXNREGION *region; LOG *lp; TXN_DETAIL *txnp; time_t last_ckp_time, now; u_int32_t bytes, mbytes; int interval, ret; PANIC_CHECK(dbenv); ENV_REQUIRES_CONFIG(dbenv, dbenv->tx_handle, "txn_checkpoint", DB_INIT_TXN); mgr = dbenv->tx_handle; region = mgr->reginfo.primary; dblp = dbenv->lg_handle; lp = dblp->reginfo.primary; /* * Check if we need to checkpoint. */ ZERO_LSN(ckp_lsn); if (LF_ISSET(DB_FORCE)) goto do_ckp; R_LOCK(dbenv, &dblp->reginfo); mbytes = lp->stat.st_wc_mbytes; /* * We add the current buffer offset so as to count bytes that * have not yet been written, but are sitting in the log buffer. */ bytes = lp->stat.st_wc_bytes + lp->b_off; ckp_lsn = lp->lsn; R_UNLOCK(dbenv, &dblp->reginfo); /* Don't checkpoint a quiescent database. */ if (bytes == 0 && mbytes == 0) return (0); if (kbytes != 0 && mbytes * 1024 + bytes / 1024 >= (u_int32_t)kbytes) goto do_ckp; if (minutes != 0) { (void)time(&now); R_LOCK(dbenv, &mgr->reginfo); last_ckp_time = region->time_ckp; R_UNLOCK(dbenv, &mgr->reginfo); if (now - last_ckp_time >= (time_t)(minutes * 60)) goto do_ckp; } /* * If we checked time and data and didn't go to checkpoint, * we're done. */ if (minutes != 0 || kbytes != 0) return (0); do_ckp: if (IS_ZERO_LSN(ckp_lsn)) { R_LOCK(dbenv, &dblp->reginfo); ckp_lsn = lp->lsn; R_UNLOCK(dbenv, &dblp->reginfo); } /* * We have to find an LSN such that all transactions begun * before that LSN are complete. */ R_LOCK(dbenv, &mgr->reginfo); if (IS_ZERO_LSN(region->pending_ckp)) { for (txnp = SH_TAILQ_FIRST(®ion->active_txn, __txn_detail); txnp != NULL; txnp = SH_TAILQ_NEXT(txnp, links, __txn_detail)) { /* * Look through the active transactions for the * lowest begin lsn. */ if (!IS_ZERO_LSN(txnp->begin_lsn) && log_compare(&txnp->begin_lsn, &ckp_lsn) < 0) ckp_lsn = txnp->begin_lsn; } region->pending_ckp = ckp_lsn; } else ckp_lsn = region->pending_ckp; R_UNLOCK(dbenv, &mgr->reginfo); /* * Try three times to sync the mpool buffers up to the specified LSN, * sleeping 1, 2 and 4 seconds between attempts. */ if (MPOOL_ON(dbenv)) for (interval = 1;;) { /* * memp_sync may change the lsn you pass it, so don't * pass it the actual ckp_lsn, pass it a local instead. */ sync_lsn = ckp_lsn; if ((ret = dbenv->memp_sync(dbenv, &sync_lsn)) == 0) break; /* * ret == DB_INCOMPLETE means there are still buffers * to flush, the checkpoint is not complete. */ if (ret == DB_INCOMPLETE) { if (interval > 4) return (ret); (void)__os_sleep(dbenv, interval, 0); interval *= 2; } else { __db_err(dbenv, "txn_checkpoint: failure when flushing the buffer cache %s", db_strerror(ret)); return (ret); } } if (LOGGING_ON(dbenv)) { R_LOCK(dbenv, &mgr->reginfo); last_ckp = region->last_ckp; ZERO_LSN(region->pending_ckp); R_UNLOCK(dbenv, &mgr->reginfo); if ((ret = __txn_ckp_log(dbenv, NULL, &ckp_lsn, DB_CHECKPOINT | DB_FLUSH, &ckp_lsn, &last_ckp, (int32_t)time(NULL))) != 0) { __db_err(dbenv, "txn_checkpoint: log failed at LSN [%ld %ld] %s", (long)ckp_lsn.file, (long)ckp_lsn.offset, db_strerror(ret)); return (ret); } R_LOCK(dbenv, &mgr->reginfo); /* * We want to make sure last_ckp only moves forward; since * we drop locks above and in log_put, it's possible * for two calls to __txn_ckp_log to finish in a different * order from how they were called. */ if (log_compare(®ion->last_ckp, &ckp_lsn) < 0) { region->last_ckp = ckp_lsn; (void)time(®ion->time_ckp); } R_UNLOCK(dbenv, &mgr->reginfo); } return (0); } /* * __txn_activekids -- * Return if this transaction has any active children. * * PUBLIC: int __txn_activekids __P((DB_ENV *, u_int32_t, DB_TXN *)); */ int __txn_activekids(dbenv, rectype, txnp) DB_ENV *dbenv; u_int32_t rectype; DB_TXN *txnp; { /* * On a child commit, we know that there are children (i.e., the * commiting child at the least. In that case, skip this check. */ if (rectype == DB_txn_child) return (0); if (TAILQ_FIRST(&txnp->kids) != NULL) { __db_err(dbenv, "Child transaction is active"); return (EPERM); } return (0); } /* * __txn_force_abort -- * Force an abort record into the log if the commit record * failed to get to disk. * * PUBLIC: void __txn_force_abort __P((u_int8_t *)); */ void __txn_force_abort(buffer) u_int8_t *buffer; { u_int32_t cksum, offset, opcode; u_int8_t *bp; /* * This routine depends on the layout of HDR and the __txn_regop * record in txn.src. We are passed the beginning of the commit * record in the log buffer and overwrite the commit with an abort * and recalculate the checksum. * * rectype txn_num lsn */ offset = sizeof(u_int32_t) + sizeof(u_int32_t) + sizeof(DB_LSN); bp = buffer + sizeof(HDR) + offset; opcode = TXN_ABORT; memcpy(bp, &opcode, sizeof(opcode)); cksum = __ham_func4(NULL, buffer + sizeof(HDR), offset + sizeof(u_int32_t) + sizeof(int32_t)); memcpy(buffer + SSZ(HDR, cksum), &cksum, sizeof(cksum)); } /* * __txn_preclose * Before we can close an environment, we need to check if we * were in the midst of taking care of restored transactions. If * so, then we need to close the files that we opened. * * PUBLIC: void __txn_preclose __P((DB_ENV *)); */ void __txn_preclose(dbenv) DB_ENV *dbenv; { DB_TXNMGR *mgr; DB_TXNREGION *region; int do_closefiles; mgr = (DB_TXNMGR *)dbenv->tx_handle; region = mgr->reginfo.primary; do_closefiles = 0; R_LOCK(dbenv, &mgr->reginfo); if (region != NULL && region->stat.st_nrestores <= mgr->n_discards && mgr->n_discards != 0) do_closefiles = 1; R_UNLOCK(dbenv, &mgr->reginfo); if (do_closefiles) { /* * Set the DBLOG_RECOVER flag while closing these * files so they do not create additional log records * that will confuse future recoveries. */ F_SET((DB_LOG *)dbenv->lg_handle, DBLOG_RECOVER); __log_close_files(dbenv); F_CLR((DB_LOG *)dbenv->lg_handle, DBLOG_RECOVER); } }