This refactor is done for few reasons below - to avoid deadlocks in scenarios when number of nodes are smaller < actual erasure stripe count where in N participating local lockers can lead to deadlocks across systems. - avoids expiry routines to run 1000 of separate network operations and routes per disk where as each of them are still accessing one single local entity. - it is ideal to have since globalLockServer per instance. - In a 32node deployment however, each server group is still concentrated towards the same set of lockers that partipicate during the write/read phase, unlike previous minio/dsync implementation - this potentially avoids send 32 requests instead we will still send at max requests of unique nodes participating in a write/read phase. - reduces overall chattiness on smaller setups.
368 lines
9.6 KiB
Go
368 lines
9.6 KiB
Go
/*
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* Minio Cloud Storage, (C) 2019 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 cmd
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import (
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"bufio"
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"context"
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"errors"
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"math/rand"
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"net/http"
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"sort"
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"strconv"
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"time"
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"github.com/gorilla/mux"
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"github.com/minio/minio/pkg/dsync"
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)
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const (
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// Lock maintenance interval.
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lockMaintenanceInterval = 30 * time.Second
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// Lock validity check interval.
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lockValidityCheckInterval = 5 * time.Second
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)
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// To abstract a node over network.
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type lockRESTServer struct {
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ll *localLocker
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}
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func (l *lockRESTServer) writeErrorResponse(w http.ResponseWriter, err error) {
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w.WriteHeader(http.StatusForbidden)
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w.Write([]byte(err.Error()))
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}
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// IsValid - To authenticate and verify the time difference.
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func (l *lockRESTServer) IsValid(w http.ResponseWriter, r *http.Request) bool {
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if l.ll == nil {
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l.writeErrorResponse(w, errLockNotInitialized)
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return false
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}
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if err := storageServerRequestValidate(r); err != nil {
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l.writeErrorResponse(w, err)
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return false
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}
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return true
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}
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func getLockArgs(r *http.Request) (args dsync.LockArgs, err error) {
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quorum, err := strconv.Atoi(r.URL.Query().Get(lockRESTQuorum))
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if err != nil {
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return args, err
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}
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args = dsync.LockArgs{
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Owner: r.URL.Query().Get(lockRESTOwner),
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UID: r.URL.Query().Get(lockRESTUID),
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Source: r.URL.Query().Get(lockRESTSource),
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Quorum: quorum,
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}
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var resources []string
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bio := bufio.NewScanner(r.Body)
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for bio.Scan() {
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resources = append(resources, bio.Text())
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}
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if err := bio.Err(); err != nil {
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return args, err
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}
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sort.Strings(resources)
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args.Resources = resources
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return args, nil
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}
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// HealthHandler returns success if request is authenticated.
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func (l *lockRESTServer) HealthHandler(w http.ResponseWriter, r *http.Request) {
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l.IsValid(w, r)
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}
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// LockHandler - Acquires a lock.
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func (l *lockRESTServer) LockHandler(w http.ResponseWriter, r *http.Request) {
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if !l.IsValid(w, r) {
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l.writeErrorResponse(w, errors.New("Invalid request"))
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return
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}
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args, err := getLockArgs(r)
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if err != nil {
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l.writeErrorResponse(w, err)
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return
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}
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success, err := l.ll.Lock(r.Context(), args)
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if err == nil && !success {
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err = errLockConflict
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}
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if err != nil {
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l.writeErrorResponse(w, err)
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return
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}
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}
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// UnlockHandler - releases the acquired lock.
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func (l *lockRESTServer) UnlockHandler(w http.ResponseWriter, r *http.Request) {
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if !l.IsValid(w, r) {
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l.writeErrorResponse(w, errors.New("Invalid request"))
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return
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}
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args, err := getLockArgs(r)
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if err != nil {
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l.writeErrorResponse(w, err)
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return
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}
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_, err = l.ll.Unlock(args)
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// Ignore the Unlock() "reply" return value because if err == nil, "reply" is always true
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// Consequently, if err != nil, reply is always false
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if err != nil {
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l.writeErrorResponse(w, err)
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return
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}
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}
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// LockHandler - Acquires an RLock.
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func (l *lockRESTServer) RLockHandler(w http.ResponseWriter, r *http.Request) {
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if !l.IsValid(w, r) {
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l.writeErrorResponse(w, errors.New("Invalid request"))
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return
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}
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args, err := getLockArgs(r)
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if err != nil {
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l.writeErrorResponse(w, err)
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return
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}
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success, err := l.ll.RLock(r.Context(), args)
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if err == nil && !success {
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err = errLockConflict
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}
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if err != nil {
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l.writeErrorResponse(w, err)
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return
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}
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}
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// RUnlockHandler - releases the acquired read lock.
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func (l *lockRESTServer) RUnlockHandler(w http.ResponseWriter, r *http.Request) {
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if !l.IsValid(w, r) {
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l.writeErrorResponse(w, errors.New("Invalid request"))
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return
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}
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args, err := getLockArgs(r)
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if err != nil {
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l.writeErrorResponse(w, err)
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return
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}
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// Ignore the RUnlock() "reply" return value because if err == nil, "reply" is always true.
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// Consequently, if err != nil, reply is always false
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if _, err = l.ll.RUnlock(args); err != nil {
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l.writeErrorResponse(w, err)
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return
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}
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}
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// ExpiredHandler - query expired lock status.
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func (l *lockRESTServer) ExpiredHandler(w http.ResponseWriter, r *http.Request) {
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if !l.IsValid(w, r) {
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l.writeErrorResponse(w, errors.New("Invalid request"))
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return
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}
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args, err := getLockArgs(r)
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if err != nil {
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l.writeErrorResponse(w, err)
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return
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}
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expired, err := l.ll.Expired(r.Context(), args)
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if err != nil {
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l.writeErrorResponse(w, err)
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return
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}
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if !expired {
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l.writeErrorResponse(w, errLockNotExpired)
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return
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}
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}
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// nameLockRequesterInfoPair is a helper type for lock maintenance
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type nameLockRequesterInfoPair struct {
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name string
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lri lockRequesterInfo
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}
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// getLongLivedLocks returns locks that are older than a certain time and
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// have not been 'checked' for validity too soon enough
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func getLongLivedLocks(interval time.Duration) []nameLockRequesterInfoPair {
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nlrip := []nameLockRequesterInfoPair{}
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globalLockServer.mutex.Lock()
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for name, lriArray := range globalLockServer.lockMap {
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for idx := range lriArray {
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// Check whether enough time has gone by since last check
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if time.Since(lriArray[idx].TimeLastCheck) >= interval {
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nlrip = append(nlrip, nameLockRequesterInfoPair{
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name: name,
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lri: lriArray[idx],
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})
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lriArray[idx].TimeLastCheck = UTCNow()
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}
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}
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}
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globalLockServer.mutex.Unlock()
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return nlrip
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}
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// lockMaintenance loops over locks that have been active for some time and checks back
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// with the original server whether it is still alive or not
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//
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// Following logic inside ignores the errors generated for Dsync.Active operation.
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// - server at client down
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// - some network error (and server is up normally)
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//
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// We will ignore the error, and we will retry later to get a resolve on this lock
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func lockMaintenance(ctx context.Context, interval time.Duration) error {
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objAPI := newObjectLayerFn()
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if objAPI == nil {
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return nil
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}
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z, ok := objAPI.(*erasureServerPools)
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if !ok {
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return nil
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}
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type nlock struct {
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locks int
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writer bool
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}
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updateNlocks := func(nlripsMap map[string]nlock, name string, writer bool) {
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nlk, ok := nlripsMap[name]
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if !ok {
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nlripsMap[name] = nlock{
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locks: 1,
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writer: writer,
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}
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} else {
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nlk.locks++
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nlripsMap[name] = nlk
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}
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}
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// Validate if long lived locks are indeed clean.
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// Get list of long lived locks to check for staleness.
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nlrips := getLongLivedLocks(interval)
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nlripsMap := make(map[string]nlock, len(nlrips))
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for _, nlrip := range nlrips {
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for _, c := range z.GetAllLockers() {
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ctx, cancel := context.WithTimeout(GlobalContext, 5*time.Second)
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// Call back to original server verify whether the lock is
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// still active (based on name & uid)
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expired, err := c.Expired(ctx, dsync.LockArgs{
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Owner: nlrip.lri.Owner,
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UID: nlrip.lri.UID,
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Resources: []string{nlrip.name},
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})
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cancel()
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if err != nil {
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updateNlocks(nlripsMap, nlrip.name, nlrip.lri.Writer)
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continue
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}
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if !expired {
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updateNlocks(nlripsMap, nlrip.name, nlrip.lri.Writer)
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}
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}
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// less than the quorum, we have locks expired.
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if nlripsMap[nlrip.name].locks < nlrip.lri.Quorum {
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// Purge the stale entry if it exists.
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globalLockServer.removeEntryIfExists(nlrip)
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}
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}
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return nil
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}
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// Start lock maintenance from all lock servers.
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func startLockMaintenance(ctx context.Context) {
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// Wait until the object API is ready
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// no need to start the lock maintenance
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// if ObjectAPI is not initialized.
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for {
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objAPI := newObjectLayerFn()
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if objAPI == nil {
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time.Sleep(time.Second)
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continue
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}
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break
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}
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// Initialize a new ticker with a minute between each ticks.
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ticker := time.NewTicker(lockMaintenanceInterval)
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// Stop the timer upon service closure and cleanup the go-routine.
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defer ticker.Stop()
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r := rand.New(rand.NewSource(UTCNow().UnixNano()))
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for {
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// Verifies every minute for locks held more than 2 minutes.
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select {
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case <-ctx.Done():
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return
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case <-ticker.C:
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// Start with random sleep time, so as to avoid
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// "synchronous checks" between servers
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duration := time.Duration(r.Float64() * float64(lockMaintenanceInterval))
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time.Sleep(duration)
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if err := lockMaintenance(ctx, lockValidityCheckInterval); err != nil {
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// Sleep right after an error.
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duration := time.Duration(r.Float64() * float64(lockMaintenanceInterval))
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time.Sleep(duration)
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}
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}
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}
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}
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// registerLockRESTHandlers - register lock rest router.
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func registerLockRESTHandlers(router *mux.Router) {
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lockServer := &lockRESTServer{
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ll: newLocker(),
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}
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subrouter := router.PathPrefix(lockRESTPrefix).Subrouter()
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subrouter.Methods(http.MethodPost).Path(lockRESTVersionPrefix + lockRESTMethodHealth).HandlerFunc(httpTraceHdrs(lockServer.HealthHandler))
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subrouter.Methods(http.MethodPost).Path(lockRESTVersionPrefix + lockRESTMethodLock).HandlerFunc(httpTraceHdrs(lockServer.LockHandler))
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subrouter.Methods(http.MethodPost).Path(lockRESTVersionPrefix + lockRESTMethodRLock).HandlerFunc(httpTraceHdrs(lockServer.RLockHandler))
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subrouter.Methods(http.MethodPost).Path(lockRESTVersionPrefix + lockRESTMethodUnlock).HandlerFunc(httpTraceHdrs(lockServer.UnlockHandler))
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subrouter.Methods(http.MethodPost).Path(lockRESTVersionPrefix + lockRESTMethodRUnlock).HandlerFunc(httpTraceHdrs(lockServer.RUnlockHandler))
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subrouter.Methods(http.MethodPost).Path(lockRESTVersionPrefix + lockRESTMethodExpired).HandlerFunc(httpTraceAll(lockServer.ExpiredHandler))
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globalLockServer = lockServer.ll
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go startLockMaintenance(GlobalContext)
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}
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