xl: Remove an unecessary lock with isBucketExist() (#2593)

Fixes #2566

cmd/controller_test.go

@@ -88,7 +88,7 @@ func (s *TestRPCControllerSuite) TestRPCControlLock(c *C) {
 			expectedVolPathBlockCount:   0,
 		},
 		// Test case 2.
-		// Testing the existance of entry for the last read lock (read lock with opsID "9").
+		// Testing the existence of entry for the last read lock (read lock with opsID "9").
 		{
 
 			volume:     "my-bucket",
@@ -203,11 +203,11 @@ func (s *TestRPCControllerSuite) TestRPCControlLock(c *C) {
 	// expected lock info.
 	expectedLockStats := expectedResult[0]
 	// verify the actual lock info with the expected one.
-	// verify the existance entry for first read lock (read lock with opsID "0").
+	// verify the existence entry for first read lock (read lock with opsID "0").
 	verifyRPCLockInfoResponse(expectedLockStats, *reply, c, 1)
 	expectedLockStats = expectedResult[1]
 	// verify the actual lock info with the expected one.
-	// verify the existance entry for last read lock (read lock with opsID "9").
+	// verify the existence entry for last read lock (read lock with opsID "9").
 	verifyRPCLockInfoResponse(expectedLockStats, *reply, c, 2)
 
 	// now hold a write lock in a different go routine and it should block since 10 read locks are
@@ -256,7 +256,7 @@ func (s *TestRPCControllerSuite) TestRPCControlLock(c *C) {
 		nsMutex.RUnlock("my-bucket", "my-object", strconv.Itoa(i))
 	}
 	wg.Wait()
-	// Since all the locks are released. There shouldnt be any entry in the lock info.
+	// Since all the locks are released. There should not be any entry in the lock info.
 	// and all the counters should be set to 0.
 	reply = &SystemLockState{}
 	// Call the lock instrumentation RPC end point.

cmd/lock-instrument.go

@@ -255,7 +255,7 @@ func (n *nsLockMap) deleteLockInfoEntryForOps(param nsParam, operationID string)
 			// decrease the global running and lock reference counter.
 			n.runningLockCounter--
 			n.globalLockCounter--
-			// decrease the lock referene counter for the lock info for given <volume,path> pair.
+			// decrease the lock referee counter for the lock info for given <volume,path> pair.
 			// decrease the running operation number. Its assumed that the operation is over once an attempt to release the lock is made.
 			infoMap.running--
 			// decrease the total reference count of locks jeld on <volume,path> pair.

cmd/lock-instrument_test.go

@@ -34,7 +34,7 @@ type lockStateCase struct {
 
 	expectedGlobalLockCount  int // Total number of locks held across the system, includes blocked + held locks.
 	expectedBlockedLockCount int // Total blocked lock across the system.
-	expectedRunningLockCount int // Total succesfully held locks (non-blocking).
+	expectedRunningLockCount int // Total successfully held locks (non-blocking).
 	// expected lock statu for given <volume, path> pair.
 	expectedVolPathLockCount    int // Total locks held for given <volume,path> pair, includes blocked locks.
 	expectedVolPathRunningCount int // Total succcesfully held locks for given <volume, path> pair.
@@ -601,7 +601,7 @@ func TestNsLockMapDeleteLockInfoEntryForOps(t *testing.T) {
 	}
 
 	// Case - 3.
-	// Lock state is set to Running and then an attempt to delete the info for non-existant opsID done.
+	// Lock state is set to Running and then an attempt to delete the info for non-existent opsID done.
 	nsMutex.lockMapMutex.Lock()
 	err := nsMutex.statusNoneToBlocked(param, testCases[0].lockOrigin, testCases[0].opsID, testCases[0].readLock)
 	if err != nil {
@@ -612,9 +612,9 @@ func TestNsLockMapDeleteLockInfoEntryForOps(t *testing.T) {
 	if err != nil {
 		t.Fatalf("Setting lock status to Running failed: <ERROR> %s", err)
 	}
-	actualErr = nsMutex.deleteLockInfoEntryForOps(param, "non-existant-OpsID")
+	actualErr = nsMutex.deleteLockInfoEntryForOps(param, "non-existent-OpsID")
 
-	expectedOpsIDErr := LockInfoOpsIDNotFound{param.volume, param.path, "non-existant-OpsID"}
+	expectedOpsIDErr := LockInfoOpsIDNotFound{param.volume, param.path, "non-existent-OpsID"}
 	if actualErr != expectedOpsIDErr {
 		t.Fatalf("Errors mismatch: Expected \"%s\", got \"%s\"", expectedOpsIDErr, actualErr)
 	}

cmd/namespace-lock_test.go

@@ -234,7 +234,7 @@ func TestLockStats(t *testing.T) {
 		},
 		// Test case - 6.
 		// Case where in the first 5 read locks are released, but 2 write locks are
-		// blocked waiting for the remaining 5 read locks locks to be released (10 read locks were held intially).
+		// blocked waiting for the remaining 5 read locks locks to be released (10 read locks were held initially).
 		// We check the entry for the first blocked write call here.
 		{
 

cmd/xl-v1-bucket.go

@@ -30,10 +30,6 @@ func (xl xlObjects) MakeBucket(bucket string) error {
 	if !IsValidBucketName(bucket) {
 		return BucketNameInvalid{Bucket: bucket}
 	}
-	// Verify if bucket is found.
-	if xl.isBucketExist(bucket) {
-		return toObjectErr(errVolumeExists, bucket)
-	}
 
 	// generates random string on setting MINIO_DEBUG=lock, else returns empty string.
 	// used for instrumentation on locks.
@@ -161,13 +157,6 @@ func (xl xlObjects) getBucketInfo(bucketName string) (bucketInfo BucketInfo, err
 
 // Checks whether bucket exists.
 func (xl xlObjects) isBucketExist(bucket string) bool {
-	// generates random string on setting MINIO_DEBUG=lock, else returns empty string.
-	// used for instrumentation on locks.
-	opsID := getOpsID()
-
-	nsMutex.RLock(bucket, "", opsID)
-	defer nsMutex.RUnlock(bucket, "", opsID)
-
 	// Check whether bucket exists.
 	_, err := xl.getBucketInfo(bucket)
 	if err != nil {
@@ -261,10 +250,6 @@ func (xl xlObjects) DeleteBucket(bucket string) error {
 	if !IsValidBucketName(bucket) {
 		return BucketNameInvalid{Bucket: bucket}
 	}
-	// Verify if bucket is found.
-	if !xl.isBucketExist(bucket) {
-		return BucketNotFound{Bucket: bucket}
-	}
 
 	// generates random string on setting MINIO_DEBUG=lock, else returns empty string.
 	// used for instrumentation on locks.
@@ -316,5 +301,7 @@ func (xl xlObjects) DeleteBucket(bucket string) error {
 	}); reducedErr != nil {
 		return toObjectErr(reducedErr, bucket)
 	}
+
+	// Success.
 	return nil
 }