mirror of
https://github.com/minio/minio.git
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305 lines
8.3 KiB
Go
305 lines
8.3 KiB
Go
// Copyright (c) 2015-2021 MinIO, Inc.
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//
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// This file is part of MinIO Object Storage stack
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//
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// This program is free software: you can redistribute it and/or modify
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// it under the terms of the GNU Affero General Public License as published by
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// the Free Software Foundation, either version 3 of the License, or
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// (at your option) any later version.
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//
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// This program is distributed in the hope that it will be useful
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU Affero General Public License for more details.
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//
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// You should have received a copy of the GNU Affero General Public License
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// along with this program. If not, see <http://www.gnu.org/licenses/>.
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package dsync
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import (
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"fmt"
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"io"
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"net/http"
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"net/http/httptest"
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"sync"
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"sync/atomic"
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"time"
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"github.com/gorilla/mux"
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)
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const numberOfNodes = 5
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var (
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ds *Dsync
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nodes = make([]*httptest.Server, numberOfNodes) // list of node IP addrs or hostname with ports.
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lockServers = make([]*lockServer, numberOfNodes)
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)
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func getLockArgs(r *http.Request) (args LockArgs, err error) {
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buf, err := io.ReadAll(r.Body)
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if err != nil {
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return args, err
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}
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_, err = args.UnmarshalMsg(buf)
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return args, err
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}
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type lockServerHandler struct {
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lsrv *lockServer
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}
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func (lh *lockServerHandler) 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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func (lh *lockServerHandler) ForceUnlockHandler(w http.ResponseWriter, r *http.Request) {
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args, err := getLockArgs(r)
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if err != nil {
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lh.writeErrorResponse(w, err)
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return
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}
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if _, err = lh.lsrv.ForceUnlock(&args); err != nil {
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lh.writeErrorResponse(w, err)
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return
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}
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}
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func (lh *lockServerHandler) RefreshHandler(w http.ResponseWriter, r *http.Request) {
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args, err := getLockArgs(r)
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if err != nil {
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lh.writeErrorResponse(w, err)
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return
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}
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reply, err := lh.lsrv.Refresh(&args)
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if err != nil {
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lh.writeErrorResponse(w, err)
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return
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}
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if !reply {
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lh.writeErrorResponse(w, errLockNotFound)
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return
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}
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}
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func (lh *lockServerHandler) LockHandler(w http.ResponseWriter, r *http.Request) {
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args, err := getLockArgs(r)
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if err != nil {
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lh.writeErrorResponse(w, err)
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return
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}
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reply, err := lh.lsrv.Lock(&args)
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if err == nil && !reply {
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err = errLockConflict
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}
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if err != nil {
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lh.writeErrorResponse(w, err)
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return
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}
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}
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func (lh *lockServerHandler) UnlockHandler(w http.ResponseWriter, r *http.Request) {
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args, err := getLockArgs(r)
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if err != nil {
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lh.writeErrorResponse(w, err)
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return
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}
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_, err = lh.lsrv.Unlock(&args)
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if err != nil {
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lh.writeErrorResponse(w, err)
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return
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}
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}
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func (lh *lockServerHandler) RUnlockHandler(w http.ResponseWriter, r *http.Request) {
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args, err := getLockArgs(r)
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if err != nil {
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lh.writeErrorResponse(w, err)
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return
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}
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_, err = lh.lsrv.RUnlock(&args)
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if err != nil {
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lh.writeErrorResponse(w, err)
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return
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}
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}
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func (lh *lockServerHandler) HealthHandler(w http.ResponseWriter, r *http.Request) {}
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func (lh *lockServerHandler) RLockHandler(w http.ResponseWriter, r *http.Request) {
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args, err := getLockArgs(r)
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if err != nil {
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lh.writeErrorResponse(w, err)
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return
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}
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reply, err := lh.lsrv.RLock(&args)
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if err == nil && !reply {
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err = errLockConflict
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}
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if err != nil {
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lh.writeErrorResponse(w, err)
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return
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}
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}
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func stopLockServers() {
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for i := 0; i < numberOfNodes; i++ {
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nodes[i].Close()
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}
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}
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func startLockServers() {
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for i := 0; i < numberOfNodes; i++ {
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lsrv := &lockServer{
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mutex: sync.Mutex{},
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lockMap: make(map[string]int64),
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}
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lockServer := lockServerHandler{
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lsrv: lsrv,
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}
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lockServers[i] = lsrv
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router := mux.NewRouter().SkipClean(true)
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subrouter := router.PathPrefix("/").Subrouter()
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subrouter.Methods(http.MethodPost).Path("/v1/health").HandlerFunc(lockServer.HealthHandler)
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subrouter.Methods(http.MethodPost).Path("/v1/refresh").HandlerFunc(lockServer.RefreshHandler)
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subrouter.Methods(http.MethodPost).Path("/v1/lock").HandlerFunc(lockServer.LockHandler)
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subrouter.Methods(http.MethodPost).Path("/v1/rlock").HandlerFunc(lockServer.RLockHandler)
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subrouter.Methods(http.MethodPost).Path("/v1/unlock").HandlerFunc(lockServer.UnlockHandler)
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subrouter.Methods(http.MethodPost).Path("/v1/runlock").HandlerFunc(lockServer.RUnlockHandler)
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subrouter.Methods(http.MethodPost).Path("/v1/force-unlock").HandlerFunc(lockServer.ForceUnlockHandler)
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nodes[i] = httptest.NewServer(router)
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}
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}
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const WriteLock = -1
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type lockServer struct {
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mutex sync.Mutex
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// Map of locks, with negative value indicating (exclusive) write lock
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// and positive values indicating number of read locks
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lockMap map[string]int64
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// Refresh returns lock not found if set to true
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lockNotFound bool
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// Set to true if you want peers servers to do not respond
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responseDelay int64
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}
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func (l *lockServer) setRefreshReply(refreshed bool) {
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l.mutex.Lock()
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defer l.mutex.Unlock()
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l.lockNotFound = !refreshed
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}
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func (l *lockServer) setResponseDelay(responseDelay time.Duration) {
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atomic.StoreInt64(&l.responseDelay, int64(responseDelay))
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}
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func (l *lockServer) Lock(args *LockArgs) (reply bool, err error) {
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if d := atomic.LoadInt64(&l.responseDelay); d != 0 {
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time.Sleep(time.Duration(d))
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}
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l.mutex.Lock()
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defer l.mutex.Unlock()
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if _, reply = l.lockMap[args.Resources[0]]; !reply {
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l.lockMap[args.Resources[0]] = WriteLock // No locks held on the given name, so claim write lock
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}
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reply = !reply // Negate *reply to return true when lock is granted or false otherwise
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return reply, nil
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}
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func (l *lockServer) Unlock(args *LockArgs) (reply bool, err error) {
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if d := atomic.LoadInt64(&l.responseDelay); d != 0 {
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time.Sleep(time.Duration(d))
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}
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l.mutex.Lock()
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defer l.mutex.Unlock()
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var locksHeld int64
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if locksHeld, reply = l.lockMap[args.Resources[0]]; !reply { // No lock is held on the given name
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return false, fmt.Errorf("Unlock attempted on an unlocked entity: %s", args.Resources[0])
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}
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if reply = locksHeld == WriteLock; !reply { // Unless it is a write lock
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return false, fmt.Errorf("Unlock attempted on a read locked entity: %s (%d read locks active)", args.Resources[0], locksHeld)
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}
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delete(l.lockMap, args.Resources[0]) // Remove the write lock
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return true, nil
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}
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const ReadLock = 1
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func (l *lockServer) RLock(args *LockArgs) (reply bool, err error) {
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if d := atomic.LoadInt64(&l.responseDelay); d != 0 {
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time.Sleep(time.Duration(d))
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}
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l.mutex.Lock()
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defer l.mutex.Unlock()
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var locksHeld int64
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if locksHeld, reply = l.lockMap[args.Resources[0]]; !reply {
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l.lockMap[args.Resources[0]] = ReadLock // No locks held on the given name, so claim (first) read lock
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reply = true
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} else if reply = locksHeld != WriteLock; reply { // Unless there is a write lock
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l.lockMap[args.Resources[0]] = locksHeld + ReadLock // Grant another read lock
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}
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return reply, nil
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}
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func (l *lockServer) RUnlock(args *LockArgs) (reply bool, err error) {
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if d := atomic.LoadInt64(&l.responseDelay); d != 0 {
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time.Sleep(time.Duration(d))
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}
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l.mutex.Lock()
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defer l.mutex.Unlock()
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var locksHeld int64
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if locksHeld, reply = l.lockMap[args.Resources[0]]; !reply { // No lock is held on the given name
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return false, fmt.Errorf("RUnlock attempted on an unlocked entity: %s", args.Resources[0])
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}
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if reply = locksHeld != WriteLock; !reply { // A write-lock is held, cannot release a read lock
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return false, fmt.Errorf("RUnlock attempted on a write locked entity: %s", args.Resources[0])
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}
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if locksHeld > ReadLock {
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l.lockMap[args.Resources[0]] = locksHeld - ReadLock // Remove one of the read locks held
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} else {
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delete(l.lockMap, args.Resources[0]) // Remove the (last) read lock
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}
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return reply, nil
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}
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func (l *lockServer) Refresh(args *LockArgs) (reply bool, err error) {
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if d := atomic.LoadInt64(&l.responseDelay); d != 0 {
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time.Sleep(time.Duration(d))
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}
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l.mutex.Lock()
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defer l.mutex.Unlock()
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reply = !l.lockNotFound
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return reply, nil
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}
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func (l *lockServer) ForceUnlock(args *LockArgs) (reply bool, err error) {
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if d := atomic.LoadInt64(&l.responseDelay); d != 0 {
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time.Sleep(time.Duration(d))
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}
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l.mutex.Lock()
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defer l.mutex.Unlock()
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if len(args.UID) != 0 {
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return false, fmt.Errorf("ForceUnlock called with non-empty UID: %s", args.UID)
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}
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delete(l.lockMap, args.Resources[0]) // Remove the lock (irrespective of write or read lock)
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reply = true
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return reply, nil
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}
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