X-Git-Url: https://git.ozlabs.org/?p=ccan;a=blobdiff_plain;f=ccan%2Ftdb%2Ftransaction.c;h=e55285f94cc6609a2afa720d39fe66d2261a36fe;hp=4c261598972dad139442abc12e03ed3a37cc5379;hb=1bc7c4367132a36c05ac1b3afcbec70a6e26540d;hpb=03c1876179e48121ab2bb445053fcb8371f36e5e

diff --git a/ccan/tdb/transaction.c b/ccan/tdb/transaction.c
index 4c261598..e55285f9 100644
--- a/ccan/tdb/transaction.c
+++ b/ccan/tdb/transaction.c
@@ -85,11 +85,13 @@
     still available, but no transaction recovery area is used and no
     fsync/msync calls are made.
 
-  - if TDB_NO_NESTING is passed to flags in tdb open then transaction
-    nesting is disabled. tdb_transaction_start() will then implicitely
-    cancel any pending transactions and always start a new transaction
-    context instead of nesting.
+  - if TDB_ALLOW_NESTING is passed to flags in tdb open, or added using
+    tdb_add_flags() transaction is enabled.
+    The default is that transaction nesting is not allowed and an attempt
+    to create a nested transaction will fail with TDB_ERR_NESTING.
 
+    Beware. when transactions are nested a transaction successfully
+    completed with tdb_transaction_commit() can be silently unrolled later.
 */
 
 
@@ -127,6 +129,9 @@ struct tdb_transaction {
 
 	/* old file size before transaction */
 	tdb_len_t old_map_size;
+
+	/* we should re-pack on commit */
+	bool need_repack;
 };
 
 
@@ -382,7 +387,8 @@ static int transaction_oob(struct tdb_context *tdb, tdb_off_t len, int probe)
 	if (len <= tdb->map_size) {
 		return 0;
 	}
-	return TDB_ERRCODE(TDB_ERR_IO, -1);
+	tdb->ecode = TDB_ERR_IO;
+	return -1;
 }
 
 /*
@@ -397,6 +403,8 @@ static int transaction_expand_file(struct tdb_context *tdb, tdb_off_t size,
 		return -1;
 	}
 
+	tdb->transaction->need_repack = true;
+
 	return 0;
 }
 
@@ -423,6 +431,10 @@ static const struct tdb_methods transaction_methods = {
 */
 static int transaction_sync(struct tdb_context *tdb, tdb_off_t offset, tdb_len_t length)
 {	
+	if (tdb->flags & TDB_NOSYNC) {
+		return 0;
+	}
+
 	if (fsync(tdb->fd) != 0) {
 		tdb->ecode = TDB_ERR_IO;
 		TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_transaction: fsync failed\n"));
@@ -523,16 +535,15 @@ int tdb_transaction_start(struct tdb_context *tdb)
 
 	/* cope with nested tdb_transaction_start() calls */
 	if (tdb->transaction != NULL) {
-		tdb_trace(tdb, "tdb_transaction_start");
-		if (!tdb->flags & TDB_NO_NESTING) {
-			tdb->transaction->nesting++;
-			TDB_LOG((tdb, TDB_DEBUG_TRACE, "tdb_transaction_start: nesting %d\n", 
-				 tdb->transaction->nesting));
-			return 0;
-		} else {
-			tdb_transaction_cancel_internal(tdb);
-			TDB_LOG((tdb, TDB_DEBUG_TRACE, "tdb_transaction_start: cancelling previous transaction\n"));
+		if (!(tdb->flags & TDB_ALLOW_NESTING)) {
+			tdb->ecode = TDB_ERR_NESTING;
+			return -1;
 		}
+		tdb_trace(tdb, "tdb_transaction_start");
+		tdb->transaction->nesting++;
+		TDB_LOG((tdb, TDB_DEBUG_TRACE, "tdb_transaction_start: nesting %d\n", 
+			 tdb->transaction->nesting));
+		return 0;
 	}
 
 	if (tdb->num_locks != 0 || tdb->global_lock.count) {
@@ -989,6 +1000,7 @@ int tdb_transaction_commit(struct tdb_context *tdb)
 {	
 	const struct tdb_methods *methods;
 	int i;
+	bool need_repack;
 
 	if (tdb->transaction == NULL) {
 		TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_transaction_commit: no transaction\n"));
@@ -1066,11 +1078,9 @@ int tdb_transaction_commit(struct tdb_context *tdb)
 	SAFE_FREE(tdb->transaction->blocks);
 	tdb->transaction->num_blocks = 0;
 
-	if (!(tdb->flags & TDB_NOSYNC)) {
-		/* ensure the new data is on disk */
-		if (transaction_sync(tdb, 0, tdb->map_size) == -1) {
-			return -1;
-		}
+	/* ensure the new data is on disk */
+	if (transaction_sync(tdb, 0, tdb->map_size) == -1) {
+		return -1;
 	}
 
 	tdb_brlock(tdb, GLOBAL_LOCK, F_UNLCK, F_SETLKW, 0, 1);
@@ -1090,10 +1100,16 @@ int tdb_transaction_commit(struct tdb_context *tdb)
 	utime(tdb->name, NULL);
 #endif
 
+	need_repack = tdb->transaction->need_repack;
+
 	/* use a transaction cancel to free memory and remove the
 	   transaction locks */
 	tdb_transaction_cancel_internal(tdb);
 
+	if (need_repack) {
+		return tdb_repack(tdb);
+	}
+
 	return 0;
 }