minio/xl-v1-namespace.go
Harshavardhana 141a44bfbf xl: Fix ReadFile to keep the order always for reading the data back. (#1339)
Also fixes a stackoverflow bug in namespace locking.
2016-04-25 12:47:31 -07:00

72 lines
1.8 KiB
Go

/*
* Minio Cloud Storage, (C) 2016 Minio, Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package main
import "sync"
// nameSpaceParam - carries name space resource.
type nameSpaceParam struct {
volume string
path string
}
// nameSpaceLock - provides primitives for locking critical namespace regions.
type nameSpaceLock struct {
rwMutex *sync.RWMutex
count uint
}
func (nsLock *nameSpaceLock) InUse() bool {
return nsLock.count != 0
}
// Lock acquires write lock and increments the namespace counter.
func (nsLock *nameSpaceLock) Lock() {
nsLock.rwMutex.Lock()
nsLock.count++
}
// Unlock releases write lock and decrements the namespace counter.
func (nsLock *nameSpaceLock) Unlock() {
nsLock.rwMutex.Unlock()
if nsLock.count != 0 {
nsLock.count--
}
}
// RLock acquires read lock and increments the namespace counter.
func (nsLock *nameSpaceLock) RLock() {
nsLock.rwMutex.RLock()
nsLock.count++
}
// RUnlock release read lock and decrements the namespace counter.
func (nsLock *nameSpaceLock) RUnlock() {
nsLock.rwMutex.RUnlock()
if nsLock.count != 0 {
nsLock.count--
}
}
// newNSLock - provides a new instance of namespace locking primitives.
func newNSLock() *nameSpaceLock {
return &nameSpaceLock{
rwMutex: &sync.RWMutex{},
count: 0,
}
}