9472299308
This patch brings in the removal of debug logging altogether, instead we bring in the functionality of being able to trace the errors properly pointing back to the origination of the problem. To enable tracing you need to enable "MINIO_TRACE" set to "1" or "true" environment variable which would print back traces whenever there is an error which is unhandled or at the handler layer. By default this tracing is turned off and only user level logging is provided.
129 lines
3 KiB
Go
129 lines
3 KiB
Go
/*
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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 (
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"errors"
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"sync"
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)
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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 the namespace resource.
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func (n *nsLockMap) lock(volume, path string, readLock bool) {
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n.mutex.Lock()
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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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n.lockMap[param] = nsLk
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}
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nsLk.ref++
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// Unlock map before Locking NS which might block.
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n.mutex.Unlock()
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// Locking here can block.
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if readLock {
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nsLk.RLock()
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} else {
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nsLk.Lock()
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}
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}
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// Unlock the namespace resource.
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func (n *nsLockMap) unlock(volume, path string, readLock bool) {
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// nsLk.Unlock() will not block, hence locking the map for the entire function is fine.
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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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if readLock {
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nsLk.RUnlock()
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} else {
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nsLk.Unlock()
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}
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if nsLk.ref == 0 {
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errorIf(errors.New("Namespace reference count cannot be 0."), "Invalid reference count detected.")
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}
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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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// Remove from the map if there are no more references.
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delete(n.lockMap, param)
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}
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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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readLock := false
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n.lock(volume, path, readLock)
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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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readLock := false
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n.unlock(volume, path, readLock)
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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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readLock := true
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n.lock(volume, path, readLock)
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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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readLock := true
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n.unlock(volume, path, readLock)
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}
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