X-Git-Url: http://git.ozlabs.org/?p=ccan;a=blobdiff_plain;f=ccan%2Ftdb%2Flock.c;h=19b92d9ae09c63152b87d10062b1363a8c063516;hp=4f8970fd34bc4e7766e2748e2bbf077ad76a5f97;hb=a879e3e2859e17496f29e14b8f393583b2c93f19;hpb=d92b8a7d9a050eb9735e48a8d37a5833500242d3

diff --git a/ccan/tdb/lock.c b/ccan/tdb/lock.c
index 4f8970fd..19b92d9a 100644
--- a/ccan/tdb/lock.c
+++ b/ccan/tdb/lock.c
@@ -224,12 +224,24 @@ static tdb_off_t lock_offset(int list)
 	return FREELIST_TOP + 4*list;
 }
 
+static struct tdb_lock_type *find_nestlock(struct tdb_context *tdb,
+					   tdb_off_t offset)
+{
+	unsigned int i;
+
+	for (i=0; i<tdb->num_lockrecs; i++) {
+		if (tdb->lockrecs[i].off == offset) {
+			return &tdb->lockrecs[i];
+		}
+	}
+	return NULL;
+}
+
 /* lock an offset in the database. */
 int tdb_nest_lock(struct tdb_context *tdb, uint32_t offset, int ltype,
 		  enum tdb_lock_flags flags)
 {
 	struct tdb_lock_type *new_lck;
-	int i;
 
 	if (offset >= lock_offset(tdb->header.hash_size)) {
 		tdb->ecode = TDB_ERR_LOCK;
@@ -240,24 +252,14 @@ int tdb_nest_lock(struct tdb_context *tdb, uint32_t offset, int ltype,
 	if (tdb->flags & TDB_NOLOCK)
 		return 0;
 
-	for (i=0; i<tdb->num_lockrecs; i++) {
-		if (tdb->lockrecs[i].off == offset) {
-			if (tdb->lockrecs[i].count == 0) {
-				/*
-				 * Can't happen, see tdb_unlock(). It should
-				 * be an assert.
-				 */
-				TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_lock: "
-					 "lck->count == 0 for offset %u",
-					 offset));
-			}
-			/*
-			 * Just increment the in-memory struct, posix locks
-			 * don't stack.
-			 */
-			tdb->lockrecs[i].count++;
-			return 0;
-		}
+	new_lck = find_nestlock(tdb, offset);
+	if (new_lck) {
+		/*
+		 * Just increment the in-memory struct, posix locks
+		 * don't stack.
+		 */
+		new_lck->count++;
+		return 0;
 	}
 
 	new_lck = (struct tdb_lock_type *)realloc(
@@ -332,8 +334,7 @@ int tdb_nest_unlock(struct tdb_context *tdb, uint32_t offset, int ltype,
 		    bool mark_lock)
 {
 	int ret = -1;
-	int i;
-	struct tdb_lock_type *lck = NULL;
+	struct tdb_lock_type *lck;
 
 	if (tdb->flags & TDB_NOLOCK)
 		return 0;
@@ -344,13 +345,7 @@ int tdb_nest_unlock(struct tdb_context *tdb, uint32_t offset, int ltype,
 		return ret;
 	}
 
-	for (i=0; i<tdb->num_lockrecs; i++) {
-		if (tdb->lockrecs[i].off == offset) {
-			lck = &tdb->lockrecs[i];
-			break;
-		}
-	}
-
+	lck = find_nestlock(tdb, offset);
 	if ((lck == NULL) || (lck->count == 0)) {
 		TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_unlock: count is 0\n"));
 		return -1;
@@ -420,18 +415,7 @@ 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);
 }
 
 /*
@@ -439,16 +423,7 @@ 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);
 }
 
 
@@ -694,11 +669,52 @@ 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 extra;
+}
+
+/* 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, extra = 0;
+
+	if (tdb->allrecord_lock.count != 0) {
+		tdb_brunlock(tdb, tdb->allrecord_lock.ltype,
+			     FREELIST_TOP, 4*tdb->header.hash_size);
+		tdb->allrecord_lock.count = 0;
+	}
+
+	for (i=0;i<tdb->num_lockrecs;i++) {
+		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_locks = extra;
+	tdb->num_lockrecs = extra;
+	if (tdb->num_lockrecs == 0) {
+		SAFE_FREE(tdb->lockrecs);
 	}
-	return false;
 }