X-Git-Url: http://git.ozlabs.org/?p=ccan;a=blobdiff_plain;f=ccan%2Ftdb%2Flock.c;h=73d34417e727196b56c1787f2b84bfc97a618d4e;hp=920ba95fe0515a7773ddefd61098510974c18f23;hb=5945c4dc1eed81c189b62612ca3c003a36e0c247;hpb=bc1c29d566924ebb7a303dfeb732a5303a59a9b3

diff --git a/ccan/tdb/lock.c b/ccan/tdb/lock.c
index 920ba95f..73d34417 100644
--- a/ccan/tdb/lock.c
+++ b/ccan/tdb/lock.c
@@ -277,12 +277,10 @@ int tdb_nest_lock(struct tdb_context *tdb, uint32_t offset, int ltype,
 		return -1;
 	}
 
-	tdb->num_locks++;
-
 	tdb->lockrecs[tdb->num_lockrecs].off = offset;
 	tdb->lockrecs[tdb->num_lockrecs].count = 1;
 	tdb->lockrecs[tdb->num_lockrecs].ltype = ltype;
-	tdb->num_lockrecs += 1;
+	tdb->num_lockrecs++;
 
 	return 0;
 }
@@ -368,17 +366,12 @@ int tdb_nest_unlock(struct tdb_context *tdb, uint32_t offset, int ltype,
 	} else {
 		ret = tdb->methods->brunlock(tdb, ltype, offset, 1);
 	}
-	tdb->num_locks--;
 
 	/*
 	 * Shrink the array by overwriting the element just unlocked with the
 	 * last array element.
 	 */
-
-	if (tdb->num_lockrecs > 1) {
-		*lck = tdb->lockrecs[tdb->num_lockrecs-1];
-	}
-	tdb->num_lockrecs -= 1;
+	*lck = tdb->lockrecs[--tdb->num_lockrecs];
 
 	/*
 	 * We don't bother with realloc when the array shrinks, but if we have
@@ -415,18 +408,7 @@ int tdb_unlock(struct tdb_context *tdb, int list, int ltype)
  */
 int tdb_transaction_lock(struct tdb_context *tdb, int ltype)
 {
-	if (tdb->transaction_lock_count > 0) {
-		tdb->transaction_lock_count++;
-		return 0;
-	}
-
-	if (tdb->methods->brlock(tdb, ltype, TRANSACTION_LOCK, 1, TDB_LOCK_WAIT) == -1) {
-		TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_transaction_lock: failed to get transaction lock\n"));
-		tdb->ecode = TDB_ERR_LOCK;
-		return -1;
-	}
-	tdb->transaction_lock_count++;
-	return 0;
+	return tdb_nest_lock(tdb, TRANSACTION_LOCK, ltype, TDB_LOCK_WAIT);
 }
 
 /*
@@ -434,16 +416,7 @@ int tdb_transaction_lock(struct tdb_context *tdb, int ltype)
  */
 int tdb_transaction_unlock(struct tdb_context *tdb, int ltype)
 {
-	int ret;
-	if (tdb->transaction_lock_count > 1) {
-		tdb->transaction_lock_count--;
-		return 0;
-	}
-	ret = tdb->methods->brunlock(tdb, ltype, TRANSACTION_LOCK, 1);
-	if (ret == 0) {
-		tdb->transaction_lock_count = 0;
-	}
-	return ret;
+	return tdb_nest_unlock(tdb, TRANSACTION_LOCK, ltype, false);
 }
 
 
@@ -689,19 +662,30 @@ int tdb_unlock_record(struct tdb_context *tdb, tdb_off_t off)
 
 bool tdb_have_extra_locks(struct tdb_context *tdb)
 {
+	unsigned int extra = tdb->num_lockrecs;
+
 	if (tdb->allrecord_lock.count) {
 		return true;
 	}
-	if (tdb->num_lockrecs) {
-		return true;
+
+	/* We always hold the active lock if CLEAR_IF_FIRST. */
+	if (find_nestlock(tdb, ACTIVE_LOCK)) {
+		extra--;
+	}
+
+	/* In a transaction, we expect to hold the transaction lock */
+	if (tdb->transaction && find_nestlock(tdb, TRANSACTION_LOCK)) {
+		extra--;
 	}
-	return false;
+
+	return extra;
 }
 
-/* The transaction code uses this to remove all locks. */
+/* The transaction code uses this to remove all locks.  Note that this
+   may include OPEN_LOCK. */
 void tdb_release_extra_locks(struct tdb_context *tdb)
 {
-	unsigned int i;
+	unsigned int i, extra = 0;
 
 	if (tdb->allrecord_lock.count != 0) {
 		tdb_brunlock(tdb, tdb->allrecord_lock.ltype,
@@ -710,10 +694,19 @@ void tdb_release_extra_locks(struct tdb_context *tdb)
 	}
 
 	for (i=0;i<tdb->num_lockrecs;i++) {
-		tdb_brunlock(tdb, tdb->lockrecs[i].ltype,
-			     tdb->lockrecs[i].off, 1);
+		struct tdb_lock_type *lck = &tdb->lockrecs[i];
+
+		/* Don't release transaction or active locks! */
+		if (tdb->transaction && lck->off == TRANSACTION_LOCK) {
+			tdb->lockrecs[extra++] = *lck;
+		} else if (lck->off == ACTIVE_LOCK) {
+			tdb->lockrecs[extra++] = *lck;
+		} else {
+			tdb_brunlock(tdb, lck->ltype, lck->off, 1);
+		}
+	}
+	tdb->num_lockrecs = extra;
+	if (tdb->num_lockrecs == 0) {
+		SAFE_FREE(tdb->lockrecs);
 	}
-	tdb->num_locks = 0;
-	tdb->num_lockrecs = 0;
-	SAFE_FREE(tdb->lockrecs);
 }