Harshavardhana
9 years ago
committed by
Anand Babu (AB) Periasamy
parent
8deddb82f4
commit
984903cce1
@ -0,0 +1,128 @@ |
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/* |
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* Minio Cloud Storage, (C) 2016 Minio, Inc. |
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* |
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* Licensed under the Apache License, Version 2.0 (the "License"); |
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* you may not use this file except in compliance with the License. |
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* You may obtain a copy of the License at |
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* |
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* http://www.apache.org/licenses/LICENSE-2.0
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* |
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* Unless required by applicable law or agreed to in writing, software |
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* distributed under the License is distributed on an "AS IS" BASIS, |
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
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* See the License for the specific language governing permissions and |
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* limitations under the License. |
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*/ |
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package main |
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import "sync" |
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// nsParam - carries name space resource.
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type nsParam struct { |
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volume string |
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path string |
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} |
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// nsLock - provides primitives for locking critical namespace regions.
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type nsLock struct { |
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*sync.RWMutex |
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ref uint |
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} |
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// nsLockMap - namespace lock map, provides primitives to Lock,
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// Unlock, RLock and RUnlock.
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type nsLockMap struct { |
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lockMap map[nsParam]*nsLock |
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mutex *sync.Mutex |
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} |
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// Global name space lock.
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var nsMutex *nsLockMap |
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// initNSLock - initialize name space lock map.
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func initNSLock() { |
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nsMutex = &nsLockMap{ |
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lockMap: make(map[nsParam]*nsLock), |
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mutex: &sync.Mutex{}, |
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} |
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} |
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// Lock - locks the given resource for writes, using a previously
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// allocated name space lock or initializing a new one.
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func (n *nsLockMap) Lock(volume, path string) { |
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n.mutex.Lock() |
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defer n.mutex.Unlock() |
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param := nsParam{volume, path} |
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nsLk, found := n.lockMap[param] |
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if !found { |
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nsLk = &nsLock{ |
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RWMutex: &sync.RWMutex{}, |
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ref: 0, |
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} |
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} |
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// Acquire a write lock and update reference counter.
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nsLk.Lock() |
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nsLk.ref++ |
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n.lockMap[param] = nsLk |
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} |
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// Unlock - unlocks any previously acquired write locks.
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func (n *nsLockMap) Unlock(volume, path string) { |
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n.mutex.Lock() |
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defer n.mutex.Unlock() |
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param := nsParam{volume, path} |
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if nsLk, found := n.lockMap[param]; found { |
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// Unlock a write lock and update reference counter.
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nsLk.Unlock() |
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if nsLk.ref != 0 { |
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nsLk.ref-- |
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} |
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if nsLk.ref != 0 { |
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n.lockMap[param] = nsLk |
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} |
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} |
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} |
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// RLock - locks any previously acquired read locks.
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func (n *nsLockMap) RLock(volume, path string) { |
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n.mutex.Lock() |
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defer n.mutex.Unlock() |
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param := nsParam{volume, path} |
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nsLk, found := n.lockMap[param] |
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if !found { |
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nsLk = &nsLock{ |
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RWMutex: &sync.RWMutex{}, |
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ref: 0, |
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} |
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} |
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// Acquire a read lock and update reference counter.
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nsLk.RLock() |
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nsLk.ref++ |
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n.lockMap[param] = nsLk |
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} |
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// RUnlock - unlocks any previously acquired read locks.
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func (n *nsLockMap) RUnlock(volume, path string) { |
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n.mutex.Lock() |
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defer n.mutex.Unlock() |
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param := nsParam{volume, path} |
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if nsLk, found := n.lockMap[param]; found { |
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// Unlock a read lock and update reference counter.
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nsLk.RUnlock() |
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if nsLk.ref != 0 { |
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nsLk.ref-- |
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} |
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if nsLk.ref != 0 { |
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n.lockMap[param] = nsLk |
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} |
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} |
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} |
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@ -1,71 +0,0 @@ |
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/* |
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* Minio Cloud Storage, (C) 2016 Minio, Inc. |
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* |
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* Licensed under the Apache License, Version 2.0 (the "License"); |
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* you may not use this file except in compliance with the License. |
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* You may obtain a copy of the License at |
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* |
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* http://www.apache.org/licenses/LICENSE-2.0
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* |
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* Unless required by applicable law or agreed to in writing, software |
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* distributed under the License is distributed on an "AS IS" BASIS, |
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
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* See the License for the specific language governing permissions and |
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* limitations under the License. |
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*/ |
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package main |
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import "sync" |
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// nameSpaceParam - carries name space resource.
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type nameSpaceParam struct { |
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volume string |
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path string |
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} |
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// nameSpaceLock - provides primitives for locking critical namespace regions.
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type nameSpaceLock struct { |
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rwMutex *sync.RWMutex |
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count uint |
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} |
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func (nsLock *nameSpaceLock) InUse() bool { |
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return nsLock.count != 0 |
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} |
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// Lock acquires write lock and increments the namespace counter.
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func (nsLock *nameSpaceLock) Lock() { |
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nsLock.rwMutex.Lock() |
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nsLock.count++ |
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} |
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// Unlock releases write lock and decrements the namespace counter.
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func (nsLock *nameSpaceLock) Unlock() { |
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nsLock.rwMutex.Unlock() |
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if nsLock.count != 0 { |
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nsLock.count-- |
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} |
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} |
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// RLock acquires read lock and increments the namespace counter.
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func (nsLock *nameSpaceLock) RLock() { |
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nsLock.rwMutex.RLock() |
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nsLock.count++ |
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} |
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// RUnlock release read lock and decrements the namespace counter.
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func (nsLock *nameSpaceLock) RUnlock() { |
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nsLock.rwMutex.RUnlock() |
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if nsLock.count != 0 { |
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nsLock.count-- |
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} |
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} |
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// newNSLock - provides a new instance of namespace locking primitives.
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func newNSLock() *nameSpaceLock { |
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return &nameSpaceLock{ |
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rwMutex: &sync.RWMutex{}, |
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count: 0, |
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} |
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} |
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