diff --git a/cmd/namespace-lock.go b/cmd/namespace-lock.go index b17d004e1..d4d0eebb4 100644 --- a/cmd/namespace-lock.go +++ b/cmd/namespace-lock.go @@ -133,31 +133,31 @@ type nsLockMap struct { // Indicates if namespace is part of a distributed setup. isDistXL bool lockMap map[nsParam]*nsLock - lockMapMutex sync.Mutex + lockMapMutex sync.RWMutex } // Lock the namespace resource. func (n *nsLockMap) lock(volume, path string, lockSource, opsID string, readLock bool, timeout time.Duration) (locked bool) { var nsLk *nsLock - n.lockMapMutex.Lock() + n.lockMapMutex.Lock() param := nsParam{volume, path} nsLk, found := n.lockMap[param] if !found { - nsLk = &nsLock{ + n.lockMap[param] = &nsLock{ RWLockerSync: func() RWLockerSync { if n.isDistXL { return dsync.NewDRWMutex(pathJoin(volume, path), globalDsync) } return &lsync.LRWMutex{} }(), - ref: 0, + ref: 1, } - n.lockMap[param] = nsLk + nsLk = n.lockMap[param] + } else { + // Update ref count here to avoid multiple races. + nsLk.ref++ } - nsLk.ref++ // Update ref count here to avoid multiple races. - - // Unlock map before Locking NS which might block. n.lockMapMutex.Unlock() // Locking here will block (until timeout). @@ -168,44 +168,44 @@ func (n *nsLockMap) lock(volume, path string, lockSource, opsID string, readLock } if !locked { // We failed to get the lock - n.lockMapMutex.Lock() - defer n.lockMapMutex.Unlock() - - nsLk.ref-- // Decrement ref count since we failed to get the lock + // Decrement ref count since we failed to get the lock + n.lockMapMutex.Lock() + nsLk.ref-- if nsLk.ref == 0 { // Remove from the map if there are no more references. delete(n.lockMap, param) } + n.lockMapMutex.Unlock() } return } // Unlock the namespace resource. func (n *nsLockMap) unlock(volume, path, opsID string, readLock bool) { - // nsLk.Unlock() will not block, hence locking the map for the - // entire function is fine. - n.lockMapMutex.Lock() - defer n.lockMapMutex.Unlock() - param := nsParam{volume, path} - if nsLk, found := n.lockMap[param]; found { - if readLock { - nsLk.RUnlock() - } else { - nsLk.Unlock() - } - if nsLk.ref == 0 { - logger.LogIf(context.Background(), errors.New("Namespace reference count cannot be 0")) - } - if nsLk.ref != 0 { - nsLk.ref-- - } + n.lockMapMutex.RLock() + nsLk, found := n.lockMap[param] + n.lockMapMutex.RUnlock() + if !found { + return + } + if readLock { + nsLk.RUnlock() + } else { + nsLk.Unlock() + } + n.lockMapMutex.Lock() + if nsLk.ref == 0 { + logger.LogIf(context.Background(), errors.New("Namespace reference count cannot be 0")) + } else { + nsLk.ref-- if nsLk.ref == 0 { // Remove from the map if there are no more references. delete(n.lockMap, param) } } + n.lockMapMutex.Unlock() } // Lock - locks the given resource for writes, using a previously