diff --git a/storage/innodb_plugin/ChangeLog b/storage/innodb_plugin/ChangeLog
index 9bb20dfb680..ef71ac90f84 100644
--- a/storage/innodb_plugin/ChangeLog
+++ b/storage/innodb_plugin/ChangeLog
@@ -1,3 +1,10 @@
+2010-04-27	The InnoDB Team
+
+	* handler/ha_innodb.cc, lock/lock0lock.c, row/row0mysql.c,
+	row/row0sel.c:
+	Fix Bug#48607 READ UNCOMMITTED uses more locks than READ COMMITTED
+	in InnoDB 5.1+
+
 2010-04-26	The InnoDB Team
 
 	* row/row0sel.c:
diff --git a/storage/innodb_plugin/handler/ha_innodb.cc b/storage/innodb_plugin/handler/ha_innodb.cc
index 30ccc460c72..0fc6e786f4c 100644
--- a/storage/innodb_plugin/handler/ha_innodb.cc
+++ b/storage/innodb_plugin/handler/ha_innodb.cc
@@ -5137,7 +5137,7 @@ ha_innobase::unlock_row(void)
 	case ROW_READ_WITH_LOCKS:
 		if (!srv_locks_unsafe_for_binlog
 		    && prebuilt->trx->isolation_level
-		    != TRX_ISO_READ_COMMITTED) {
+		    > TRX_ISO_READ_COMMITTED) {
 			break;
 		}
 		/* fall through */
@@ -5176,7 +5176,7 @@ ha_innobase::try_semi_consistent_read(bool yes)
 
 	if (yes
 	    && (srv_locks_unsafe_for_binlog
-		|| prebuilt->trx->isolation_level == TRX_ISO_READ_COMMITTED)) {
+		|| prebuilt->trx->isolation_level <= TRX_ISO_READ_COMMITTED)) {
 		prebuilt->row_read_type = ROW_READ_TRY_SEMI_CONSISTENT;
 	} else {
 		prebuilt->row_read_type = ROW_READ_WITH_LOCKS;
@@ -9095,7 +9095,7 @@ ha_innobase::store_lock(
 		isolation_level = trx->isolation_level;
 
 		if ((srv_locks_unsafe_for_binlog
-		     || isolation_level == TRX_ISO_READ_COMMITTED)
+		     || isolation_level <= TRX_ISO_READ_COMMITTED)
 		    && isolation_level != TRX_ISO_SERIALIZABLE
 		    && (lock_type == TL_READ || lock_type == TL_READ_NO_INSERT)
 		    && (sql_command == SQLCOM_INSERT_SELECT
diff --git a/storage/innodb_plugin/lock/lock0lock.c b/storage/innodb_plugin/lock/lock0lock.c
index 3c740df97ff..04e5fe1a65a 100644
--- a/storage/innodb_plugin/lock/lock0lock.c
+++ b/storage/innodb_plugin/lock/lock0lock.c
@@ -2400,7 +2400,7 @@ lock_rec_inherit_to_gap(
 		if (!lock_rec_get_insert_intention(lock)
 		    && !((srv_locks_unsafe_for_binlog
 			  || lock->trx->isolation_level
-			  == TRX_ISO_READ_COMMITTED)
+			  <= TRX_ISO_READ_COMMITTED)
 			 && lock_get_mode(lock) == LOCK_X)) {
 
 			lock_rec_add_to_queue(LOCK_REC | LOCK_GAP
diff --git a/storage/innodb_plugin/row/row0mysql.c b/storage/innodb_plugin/row/row0mysql.c
index 0d8d298453c..24abf8067f2 100644
--- a/storage/innodb_plugin/row/row0mysql.c
+++ b/storage/innodb_plugin/row/row0mysql.c
@@ -1458,7 +1458,7 @@ row_unlock_for_mysql(
 
 	if (UNIV_UNLIKELY
 	    (!srv_locks_unsafe_for_binlog
-	     && trx->isolation_level != TRX_ISO_READ_COMMITTED)) {
+	     && trx->isolation_level > TRX_ISO_READ_COMMITTED)) {
 
 		fprintf(stderr,
 			"InnoDB: Error: calling row_unlock_for_mysql though\n"
diff --git a/storage/innodb_plugin/row/row0sel.c b/storage/innodb_plugin/row/row0sel.c
index 92ecca2c75d..d0702a0cd2f 100644
--- a/storage/innodb_plugin/row/row0sel.c
+++ b/storage/innodb_plugin/row/row0sel.c
@@ -852,7 +852,7 @@ row_sel_get_clust_rec(
 		trx = thr_get_trx(thr);
 
 		if (srv_locks_unsafe_for_binlog
-		    || trx->isolation_level == TRX_ISO_READ_COMMITTED) {
+		    || trx->isolation_level <= TRX_ISO_READ_COMMITTED) {
 			lock_type = LOCK_REC_NOT_GAP;
 		} else {
 			lock_type = LOCK_ORDINARY;
@@ -1465,7 +1465,7 @@ rec_loop:
 
 			if (srv_locks_unsafe_for_binlog
 			    || trx->isolation_level
-			    == TRX_ISO_READ_COMMITTED) {
+			    <= TRX_ISO_READ_COMMITTED) {
 
 				if (page_rec_is_supremum(next_rec)) {
 
@@ -1522,7 +1522,7 @@ skip_lock:
 		trx = thr_get_trx(thr);
 
 		if (srv_locks_unsafe_for_binlog
-		    || trx->isolation_level == TRX_ISO_READ_COMMITTED) {
+		    || trx->isolation_level <= TRX_ISO_READ_COMMITTED) {
 
 			if (page_rec_is_supremum(rec)) {
 
@@ -3665,7 +3665,7 @@ shortcut_fails_too_big_rec:
 		    && !page_rec_is_supremum(rec)
 		    && set_also_gap_locks
 		    && !(srv_locks_unsafe_for_binlog
-			 || trx->isolation_level == TRX_ISO_READ_COMMITTED)
+			 || trx->isolation_level <= TRX_ISO_READ_COMMITTED)
 		    && prebuilt->select_lock_type != LOCK_NONE) {
 
 			/* Try to place a gap lock on the next index record
@@ -3761,7 +3761,7 @@ rec_loop:
 
 		if (set_also_gap_locks
 		    && !(srv_locks_unsafe_for_binlog
-			 || trx->isolation_level == TRX_ISO_READ_COMMITTED)
+			 || trx->isolation_level <= TRX_ISO_READ_COMMITTED)
 		    && prebuilt->select_lock_type != LOCK_NONE) {
 
 			/* Try to place a lock on the index record */
@@ -3895,7 +3895,7 @@ wrong_offs:
 			if (set_also_gap_locks
 			    && !(srv_locks_unsafe_for_binlog
 				 || trx->isolation_level
-				 == TRX_ISO_READ_COMMITTED)
+				 <= TRX_ISO_READ_COMMITTED)
 			    && prebuilt->select_lock_type != LOCK_NONE) {
 
 				/* Try to place a gap lock on the index
@@ -3931,7 +3931,7 @@ wrong_offs:
 			if (set_also_gap_locks
 			    && !(srv_locks_unsafe_for_binlog
 				 || trx->isolation_level
-				 == TRX_ISO_READ_COMMITTED)
+				 <= TRX_ISO_READ_COMMITTED)
 			    && prebuilt->select_lock_type != LOCK_NONE) {
 
 				/* Try to place a gap lock on the index
@@ -3979,7 +3979,7 @@ wrong_offs:
 
 		if (!set_also_gap_locks
 		    || srv_locks_unsafe_for_binlog
-		    || trx->isolation_level == TRX_ISO_READ_COMMITTED
+		    || trx->isolation_level <= TRX_ISO_READ_COMMITTED
 		    || (unique_search
 			&& !UNIV_UNLIKELY(rec_get_deleted_flag(rec, comp)))) {
 
@@ -4018,7 +4018,7 @@ no_gap_lock:
 			const rec_t*	old_vers;
 		case DB_SUCCESS:
 			if (srv_locks_unsafe_for_binlog
-			    || trx->isolation_level == TRX_ISO_READ_COMMITTED) {
+			    || trx->isolation_level <= TRX_ISO_READ_COMMITTED) {
 				/* Note that a record of
 				prebuilt->index was locked. */
 				prebuilt->new_rec_locks = 1;
@@ -4151,7 +4151,7 @@ no_gap_lock:
 		/* The record is delete-marked: we can skip it */
 
 		if ((srv_locks_unsafe_for_binlog
-		     || trx->isolation_level == TRX_ISO_READ_COMMITTED)
+		     || trx->isolation_level <= TRX_ISO_READ_COMMITTED)
 		    && prebuilt->select_lock_type != LOCK_NONE
 		    && !did_semi_consistent_read) {
 
@@ -4218,7 +4218,7 @@ requires_clust_rec:
 		}
 
 		if ((srv_locks_unsafe_for_binlog
-		     || trx->isolation_level == TRX_ISO_READ_COMMITTED)
+		     || trx->isolation_level <= TRX_ISO_READ_COMMITTED)
 		    && prebuilt->select_lock_type != LOCK_NONE) {
 			/* Note that both the secondary index record
 			and the clustered index record were locked. */
@@ -4231,7 +4231,7 @@ requires_clust_rec:
 			/* The record is delete marked: we can skip it */
 
 			if ((srv_locks_unsafe_for_binlog
-			     || trx->isolation_level == TRX_ISO_READ_COMMITTED)
+			     || trx->isolation_level <= TRX_ISO_READ_COMMITTED)
 			    && prebuilt->select_lock_type != LOCK_NONE) {
 
 				/* No need to keep a lock on a delete-marked
@@ -4442,7 +4442,7 @@ lock_wait_or_error:
 					       moves_up, &mtr);
 
 		if ((srv_locks_unsafe_for_binlog
-		     || trx->isolation_level == TRX_ISO_READ_COMMITTED)
+		     || trx->isolation_level <= TRX_ISO_READ_COMMITTED)
 		    && !same_user_rec) {
 
 			/* Since we were not able to restore the cursor