Move code into mdb_txn_end(). Was mdb_txn_reset0.

Side effects:
* Clean txn up a bit even before freeing it.
* Tweak DEBUG output at txn end. Add DEBUG after commit(writer).

diff --git a/libraries/liblmdb/mdb.c b/libraries/liblmdb/mdb.c
index a2a68a164130d9fcfe910e1e54051bbfe454ca42..32508dcd03915b6430fdcdbe8824f08912428553 100644 (file)
--- a/libraries/liblmdb/mdb.c
+++ b/libraries/liblmdb/mdb.c
@@ -1302,6 +1302,19 @@ static int  mdb_page_alloc(MDB_cursor *mc, int num, MDB_page **mp);
 static int  mdb_page_new(MDB_cursor *mc, uint32_t flags, int num, MDB_page **mp);
 static int  mdb_page_touch(MDB_cursor *mc);
 
+#define MDB_END_NAMES {"committed", "empty-commit", "abort", "reset", \
+       "reset-tmp", "fail-begin", "fail-beginchild"}
+enum {
+       /* mdb_txn_end operation number, for logging */
+       MDB_END_COMMITTED, MDB_END_EMPTY_COMMIT, MDB_END_ABORT, MDB_END_RESET,
+       MDB_END_RESET_TMP, MDB_END_FAIL_BEGIN, MDB_END_FAIL_BEGINCHILD
+};
+#define MDB_END_OPMASK 0x0F    /**< mask for #mdb_txn_end() operation number */
+#define MDB_END_UPDATE 0x10    /**< update env state (DBIs) */
+#define MDB_END_FREE   0x20    /**< free txn unless it is #MDB_env.%me_txn0 */
+#define MDB_END_SLOT MDB_NOTLS /**< release any reader slot if #MDB_NOTLS */
+static void mdb_txn_end(MDB_txn *txn, unsigned mode);
+
 static int  mdb_page_get(MDB_txn *txn, pgno_t pgno, MDB_page **mp, int *lvl);
 static int  mdb_page_search_root(MDB_cursor *mc,
                            MDB_val *key, int modify);
@@ -2546,12 +2559,6 @@ mdb_cursors_close(MDB_txn *txn, unsigned merge)
        }
 }
 
-#if !(MDB_DEBUG)
-#define mdb_txn_reset0(txn, act) mdb_txn_reset0(txn)
-#endif
-static void
-mdb_txn_reset0(MDB_txn *txn, const char *act);
-
 #if !(MDB_PIDLOCK)             /* Currently the same as defined(_WIN32) */
 enum Pidlock_op {
        Pidset, Pidcheck
@@ -2731,11 +2738,7 @@ mdb_txn_renew0(MDB_txn *txn)
        txn->mt_dbflags[FREE_DBI] = DB_VALID;
 
        if (env->me_maxpg < txn->mt_next_pgno) {
-               mdb_txn_reset0(txn, "renew0-mapfail");
-               if (new_notls) {
-                       txn->mt_u.reader->mr_pid = 0;
-                       txn->mt_u.reader = NULL;
-               }
+               mdb_txn_end(txn, new_notls /*0 or MDB_END_SLOT*/ | MDB_END_FAIL_BEGIN);
                return MDB_MAP_RESIZED;
        }
 
@@ -2850,7 +2853,7 @@ mdb_txn_begin(MDB_env *env, MDB_txn *parent, unsigned int flags, MDB_txn **ret)
                if (!rc)
                        rc = mdb_cursor_shadow(parent, txn);
                if (rc)
-                       mdb_txn_reset0(txn, "beginchild-fail");
+                       mdb_txn_end(txn, MDB_END_FAIL_BEGINCHILD);
        } else { /* MDB_RDONLY */
                txn->mt_dbiseqs = env->me_dbiseqs;
 renew:
@@ -2913,35 +2916,44 @@ mdb_dbis_update(MDB_txn *txn, int keep)
                env->me_numdbs = n;
 }
 
-/** Common code for #mdb_txn_reset() and #mdb_txn_abort().
+/** End a transaction, except successful commit of a nested transaction.
  * May be called twice for readonly txns: First reset it, then abort.
- * @param[in] txn the transaction handle to reset
- * @param[in] act why the transaction is being reset
+ * @param[in] txn the transaction handle to end
+ * @param[in] mode why and how to end the transaction
  */
 static void
-mdb_txn_reset0(MDB_txn *txn, const char *act)
+mdb_txn_end(MDB_txn *txn, unsigned mode)
 {
        MDB_env *env = txn->mt_env;
+#if MDB_DEBUG
+       static const char *const names[] = MDB_END_NAMES;
+#endif
 
-       /* Close any DBI handles opened in this txn */
-       mdb_dbis_update(txn, 0);
+       /* Export or close DBI handles opened in this txn */
+       mdb_dbis_update(txn, mode & MDB_END_UPDATE);
 
        DPRINTF(("%s txn %"Z"u%c %p on mdbenv %p, root page %"Z"u",
-               act, txn->mt_txnid, (txn->mt_flags & MDB_TXN_RDONLY) ? 'r' : 'w',
+               names[mode & MDB_END_OPMASK],
+               txn->mt_txnid, (txn->mt_flags & MDB_TXN_RDONLY) ? 'r' : 'w',
                (void *) txn, (void *)env, txn->mt_dbs[MAIN_DBI].md_root));
 
        if (F_ISSET(txn->mt_flags, MDB_TXN_RDONLY)) {
                if (txn->mt_u.reader) {
                        txn->mt_u.reader->mr_txnid = (txnid_t)-1;
-                       if (!(env->me_flags & MDB_NOTLS))
+                       if (!(env->me_flags & MDB_NOTLS)) {
                                txn->mt_u.reader = NULL; /* txn does not own reader */
+                       } else if (mode & MDB_END_SLOT) {
+                               txn->mt_u.reader->mr_pid = 0;
+                               txn->mt_u.reader = NULL;
+                       } /* else txn owns the slot until it does MDB_END_SLOT */
                }
                txn->mt_numdbs = 0;             /* close nothing if called again */
                txn->mt_dbxs = NULL;    /* mark txn as reset */
        } else {
                pgno_t *pghead = env->me_pghead;
 
-               mdb_cursors_close(txn, 0);
+               if (!(mode & MDB_END_UPDATE)) /* !(already closed cursors) */
+                       mdb_cursors_close(txn, 0);
                if (!(env->me_flags & MDB_WRITEMAP)) {
                        mdb_dlist_free(txn);
                }
@@ -2954,6 +2966,8 @@ mdb_txn_reset0(MDB_txn *txn, const char *act)
                        env->me_pglast = 0;
 
                        env->me_txn = NULL;
+                       mode = 0;       /* txn == env->me_txn0, do not free() it */
+
                        /* The writer mutex was locked in mdb_txn_begin. */
                        if (env->me_txns)
                                UNLOCK_MUTEX(env->me_wmutex);
@@ -2967,6 +2981,9 @@ mdb_txn_reset0(MDB_txn *txn, const char *act)
 
                mdb_midl_free(pghead);
        }
+
+       if (mode & MDB_END_FREE)
+               free(txn);
 }
 
 void
@@ -2979,7 +2996,7 @@ mdb_txn_reset(MDB_txn *txn)
        if (!(txn->mt_flags & MDB_TXN_RDONLY))
                return;
 
-       mdb_txn_reset0(txn, "reset");
+       mdb_txn_end(txn, MDB_END_RESET);
 }
 
 void
@@ -2991,13 +3008,7 @@ mdb_txn_abort(MDB_txn *txn)
        if (txn->mt_child)
                mdb_txn_abort(txn->mt_child);
 
-       mdb_txn_reset0(txn, "abort");
-       /* Free reader slot tied to this txn (if MDB_NOTLS && writable FS) */
-       if ((txn->mt_flags & MDB_TXN_RDONLY) && txn->mt_u.reader)
-               txn->mt_u.reader->mr_pid = 0;
-
-       if (txn != txn->mt_env->me_txn0)
-               free(txn);
+       mdb_txn_end(txn, MDB_END_ABORT|MDB_END_SLOT|MDB_END_FREE);
 }
 
 /** Save the freelist as of this transaction to the freeDB.
@@ -3348,12 +3359,15 @@ int
 mdb_txn_commit(MDB_txn *txn)
 {
        int             rc;
-       unsigned int i;
+       unsigned int i, end_mode;
        MDB_env *env;
 
        if (txn == NULL)
                return EINVAL;
 
+       /* mdb_txn_end() mode for a commit which writes nothing */
+       end_mode = MDB_END_EMPTY_COMMIT|MDB_END_UPDATE|MDB_END_SLOT|MDB_END_FREE;
+
        if (txn->mt_child) {
                rc = mdb_txn_commit(txn->mt_child);
                if (rc)
@@ -3363,10 +3377,7 @@ mdb_txn_commit(MDB_txn *txn)
        env = txn->mt_env;
 
        if (F_ISSET(txn->mt_flags, MDB_TXN_RDONLY)) {
-               mdb_dbis_update(txn, 1);
-               txn->mt_numdbs = 2; /* so txn_abort() doesn't close any new handles */
-               mdb_txn_abort(txn);
-               return MDB_SUCCESS;
+               goto done;
        }
 
        if (F_ISSET(txn->mt_flags, MDB_TXN_ERROR)) {
@@ -3534,7 +3545,6 @@ mdb_txn_commit(MDB_txn *txn)
        mdb_midl_free(env->me_pghead);
        env->me_pghead = NULL;
        mdb_midl_shrink(&txn->mt_free_pgs);
-       env->me_free_pgs = txn->mt_free_pgs;
 
 #if (MDB_DEBUG) > 2
        mdb_audit(txn);
@@ -3547,21 +3557,10 @@ mdb_txn_commit(MDB_txn *txn)
                goto fail;
        if ((rc = mdb_env_write_meta(txn)))
                goto fail;
-
-       /* Free P_LOOSE pages left behind in dirty_list */
-       if (!(env->me_flags & MDB_WRITEMAP))
-               mdb_dlist_free(txn);
+       end_mode = MDB_END_COMMITTED|MDB_END_UPDATE;
 
 done:
-       env->me_pglast = 0;
-       env->me_txn = NULL;
-       mdb_dbis_update(txn, 1);
-
-       if (env->me_txns)
-               UNLOCK_MUTEX(env->me_wmutex);
-       if (txn != env->me_txn0)
-               free(txn);
-
+       mdb_txn_end(txn, end_mode);
        return MDB_SUCCESS;
 
 fail:
@@ -9007,7 +9006,7 @@ mdb_env_copyfd0(MDB_env *env, HANDLE fd)
 
        if (env->me_txns) {
                /* We must start the actual read txn after blocking writers */
-               mdb_txn_reset0(txn, "reset-stage1");
+               mdb_txn_end(txn, MDB_END_RESET_TMP);
 
                /* Temporarily block writers until we snapshot the meta pages */
                wmutex = env->me_wmutex;