You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
358 lines
11 KiB
358 lines
11 KiB
/*
|
|
* Minio Cloud Storage, (C) 2016 Minio, Inc.
|
|
*
|
|
* Licensed under the Apache License, Version 2.0 (the "License");
|
|
* you may not use this file except in compliance with the License.
|
|
* You may obtain a copy of the License at
|
|
*
|
|
* http://www.apache.org/licenses/LICENSE-2.0
|
|
*
|
|
* Unless required by applicable law or agreed to in writing, software
|
|
* distributed under the License is distributed on an "AS IS" BASIS,
|
|
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
|
|
* See the License for the specific language governing permissions and
|
|
* limitations under the License.
|
|
*/
|
|
|
|
package cmd
|
|
|
|
import (
|
|
"fmt"
|
|
"math/rand"
|
|
"net/rpc"
|
|
"path"
|
|
"strings"
|
|
"sync"
|
|
"time"
|
|
|
|
router "github.com/gorilla/mux"
|
|
)
|
|
|
|
const lockRPCPath = "/minio/lock"
|
|
const lockMaintenanceLoop = 1 * time.Minute
|
|
const lockCheckValidityInterval = 2 * time.Minute
|
|
|
|
// LockArgs besides lock name, holds Token and Timestamp for session
|
|
// authentication and validation server restart.
|
|
type LockArgs struct {
|
|
Name string
|
|
Token string
|
|
Timestamp time.Time
|
|
Node string
|
|
RPCPath string
|
|
UID string
|
|
}
|
|
|
|
// SetToken - sets the token to the supplied value.
|
|
func (l *LockArgs) SetToken(token string) {
|
|
l.Token = token
|
|
}
|
|
|
|
// SetTimestamp - sets the timestamp to the supplied value.
|
|
func (l *LockArgs) SetTimestamp(tstamp time.Time) {
|
|
l.Timestamp = tstamp
|
|
}
|
|
|
|
// lockRequesterInfo stores various info from the client for each lock that is requested
|
|
type lockRequesterInfo struct {
|
|
writer bool // Bool whether write or read lock
|
|
node string // Network address of client claiming lock
|
|
rpcPath string // RPC path of client claiming lock
|
|
uid string // Uid to uniquely identify request of client
|
|
timestamp time.Time // Timestamp set at the time of initialization
|
|
timeLastCheck time.Time // Timestamp for last check of validity of lock
|
|
}
|
|
|
|
// isWriteLock returns whether the lock is a write or read lock
|
|
func isWriteLock(lri []lockRequesterInfo) bool {
|
|
return len(lri) == 1 && lri[0].writer
|
|
}
|
|
|
|
// lockServer is type for RPC handlers
|
|
type lockServer struct {
|
|
rpcPath string
|
|
mutex sync.Mutex
|
|
lockMap map[string][]lockRequesterInfo
|
|
timestamp time.Time // Timestamp set at the time of initialization. Resets naturally on minio server restart.
|
|
}
|
|
|
|
func (l *lockServer) verifyArgs(args *LockArgs) error {
|
|
if !l.timestamp.Equal(args.Timestamp) {
|
|
return errInvalidTimestamp
|
|
}
|
|
if !isRPCTokenValid(args.Token) {
|
|
return errInvalidToken
|
|
}
|
|
return nil
|
|
}
|
|
|
|
/// Distributed lock handlers
|
|
|
|
// LoginHandler - handles LoginHandler RPC call.
|
|
func (l *lockServer) LoginHandler(args *RPCLoginArgs, reply *RPCLoginReply) error {
|
|
jwt, err := newJWT(defaultTokenExpiry)
|
|
if err != nil {
|
|
return err
|
|
}
|
|
if err = jwt.Authenticate(args.Username, args.Password); err != nil {
|
|
return err
|
|
}
|
|
token, err := jwt.GenerateToken(args.Username)
|
|
if err != nil {
|
|
return err
|
|
}
|
|
reply.Token = token
|
|
reply.Timestamp = l.timestamp
|
|
return nil
|
|
}
|
|
|
|
// Lock - rpc handler for (single) write lock operation.
|
|
func (l *lockServer) Lock(args *LockArgs, reply *bool) error {
|
|
l.mutex.Lock()
|
|
defer l.mutex.Unlock()
|
|
if err := l.verifyArgs(args); err != nil {
|
|
return err
|
|
}
|
|
_, *reply = l.lockMap[args.Name]
|
|
if !*reply { // No locks held on the given name, so claim write lock
|
|
l.lockMap[args.Name] = []lockRequesterInfo{{writer: true, node: args.Node, rpcPath: args.RPCPath, uid: args.UID, timestamp: time.Now(), timeLastCheck: time.Now()}}
|
|
}
|
|
*reply = !*reply // Negate *reply to return true when lock is granted or false otherwise
|
|
return nil
|
|
}
|
|
|
|
// Unlock - rpc handler for (single) write unlock operation.
|
|
func (l *lockServer) Unlock(args *LockArgs, reply *bool) error {
|
|
l.mutex.Lock()
|
|
defer l.mutex.Unlock()
|
|
if err := l.verifyArgs(args); err != nil {
|
|
return err
|
|
}
|
|
var lri []lockRequesterInfo
|
|
lri, *reply = l.lockMap[args.Name]
|
|
if !*reply { // No lock is held on the given name
|
|
return fmt.Errorf("Unlock attempted on an unlocked entity: %s", args.Name)
|
|
}
|
|
if *reply = isWriteLock(lri); !*reply { // Unless it is a write lock
|
|
return fmt.Errorf("Unlock attempted on a read locked entity: %s (%d read locks active)", args.Name, len(lri))
|
|
}
|
|
if l.removeEntry(args.Name, args.UID, &lri) {
|
|
return nil
|
|
}
|
|
return fmt.Errorf("Unlock unable to find corresponding lock for uid: %s", args.UID)
|
|
}
|
|
|
|
// RLock - rpc handler for read lock operation.
|
|
func (l *lockServer) RLock(args *LockArgs, reply *bool) error {
|
|
l.mutex.Lock()
|
|
defer l.mutex.Unlock()
|
|
if err := l.verifyArgs(args); err != nil {
|
|
return err
|
|
}
|
|
var lri []lockRequesterInfo
|
|
lri, *reply = l.lockMap[args.Name]
|
|
if !*reply { // No locks held on the given name, so claim (first) read lock
|
|
l.lockMap[args.Name] = []lockRequesterInfo{{writer: false, node: args.Node, rpcPath: args.RPCPath, uid: args.UID, timestamp: time.Now(), timeLastCheck: time.Now()}}
|
|
*reply = true
|
|
} else {
|
|
if *reply = !isWriteLock(lri); *reply { // Unless there is a write lock
|
|
l.lockMap[args.Name] = append(l.lockMap[args.Name], lockRequesterInfo{writer: false, node: args.Node, rpcPath: args.RPCPath, uid: args.UID, timestamp: time.Now(), timeLastCheck: time.Now()})
|
|
}
|
|
}
|
|
return nil
|
|
}
|
|
|
|
// RUnlock - rpc handler for read unlock operation.
|
|
func (l *lockServer) RUnlock(args *LockArgs, reply *bool) error {
|
|
l.mutex.Lock()
|
|
defer l.mutex.Unlock()
|
|
if err := l.verifyArgs(args); err != nil {
|
|
return err
|
|
}
|
|
var lri []lockRequesterInfo
|
|
if lri, *reply = l.lockMap[args.Name]; !*reply { // No lock is held on the given name
|
|
return fmt.Errorf("RUnlock attempted on an unlocked entity: %s", args.Name)
|
|
}
|
|
if *reply = !isWriteLock(lri); !*reply { // A write-lock is held, cannot release a read lock
|
|
return fmt.Errorf("RUnlock attempted on a write locked entity: %s", args.Name)
|
|
}
|
|
if l.removeEntry(args.Name, args.UID, &lri) {
|
|
return nil
|
|
}
|
|
return fmt.Errorf("RUnlock unable to find corresponding read lock for uid: %s", args.UID)
|
|
}
|
|
|
|
// Active - rpc handler for active lock status.
|
|
func (l *lockServer) Active(args *LockArgs, reply *bool) error {
|
|
l.mutex.Lock()
|
|
defer l.mutex.Unlock()
|
|
if err := l.verifyArgs(args); err != nil {
|
|
return err
|
|
}
|
|
var lri []lockRequesterInfo
|
|
if lri, *reply = l.lockMap[args.Name]; !*reply {
|
|
return nil // No lock is held on the given name so return false
|
|
}
|
|
// Check whether uid is still active
|
|
for _, entry := range lri {
|
|
if *reply = entry.uid == args.UID; *reply {
|
|
return nil // When uid found return true
|
|
}
|
|
}
|
|
return nil // None found so return false
|
|
}
|
|
|
|
// removeEntry either, based on the uid of the lock message, removes a single entry from the
|
|
// lockRequesterInfo array or the whole array from the map (in case of a write lock or last read lock)
|
|
func (l *lockServer) removeEntry(name, uid string, lri *[]lockRequesterInfo) bool {
|
|
// Find correct entry to remove based on uid
|
|
for index, entry := range *lri {
|
|
if entry.uid == uid {
|
|
if len(*lri) == 1 {
|
|
delete(l.lockMap, name) // Remove the (last) lock
|
|
} else {
|
|
// Remove the appropriate read lock
|
|
*lri = append((*lri)[:index], (*lri)[index+1:]...)
|
|
l.lockMap[name] = *lri
|
|
}
|
|
return true
|
|
}
|
|
}
|
|
return false
|
|
}
|
|
|
|
// nameLockRequesterInfoPair is a helper type for lock maintenance
|
|
type nameLockRequesterInfoPair struct {
|
|
name string
|
|
lri lockRequesterInfo
|
|
}
|
|
|
|
// getLongLivedLocks returns locks that are older than a certain time and
|
|
// have not been 'checked' for validity too soon enough
|
|
func getLongLivedLocks(m map[string][]lockRequesterInfo, interval time.Duration) []nameLockRequesterInfoPair {
|
|
|
|
rslt := []nameLockRequesterInfoPair{}
|
|
|
|
for name, lriArray := range m {
|
|
|
|
for idx := range lriArray {
|
|
// Check whether enough time has gone by since last check
|
|
if time.Since(lriArray[idx].timeLastCheck) >= interval {
|
|
rslt = append(rslt, nameLockRequesterInfoPair{name: name, lri: lriArray[idx]})
|
|
lriArray[idx].timeLastCheck = time.Now()
|
|
}
|
|
}
|
|
}
|
|
|
|
return rslt
|
|
}
|
|
|
|
// lockMaintenance loops over locks that have been active for some time and checks back
|
|
// with the original server whether it is still alive or not
|
|
func (l *lockServer) lockMaintenance(interval time.Duration) {
|
|
|
|
l.mutex.Lock()
|
|
// get list of locks to check
|
|
nlripLongLived := getLongLivedLocks(l.lockMap, interval)
|
|
l.mutex.Unlock()
|
|
|
|
for _, nlrip := range nlripLongLived {
|
|
|
|
c := newClient(nlrip.lri.node, nlrip.lri.rpcPath)
|
|
|
|
var active bool
|
|
|
|
// Call back to original server verify whether the lock is still active (based on name & uid)
|
|
if err := c.Call("Dsync.Active", &LockArgs{Name: nlrip.name, UID: nlrip.lri.uid}, &active); err != nil {
|
|
// We failed to connect back to the server that originated the lock, this can either be due to
|
|
// - server at client down
|
|
// - some network error (and server is up normally)
|
|
//
|
|
// We will ignore the error, and we will retry later to get resolve on this lock
|
|
c.Close()
|
|
} else {
|
|
c.Close()
|
|
|
|
if !active { // The lock is no longer active at server that originated the lock
|
|
// so remove the lock from the map
|
|
l.mutex.Lock()
|
|
// Check if entry is still in map (could have been removed altogether by 'concurrent' (R)Unlock of last entry)
|
|
if lri, ok := l.lockMap[nlrip.name]; ok {
|
|
if !l.removeEntry(nlrip.name, nlrip.lri.uid, &lri) {
|
|
// Remove failed, in case it is a:
|
|
if nlrip.lri.writer {
|
|
// Writer: this should never happen as the whole (mapped) entry should have been deleted
|
|
log.Errorln("Lock maintenance failed to remove entry for write lock (should never happen)", nlrip.name, nlrip.lri, lri)
|
|
} else {
|
|
// Reader: this can happen if multiple read locks were active and the one we are looking for
|
|
// has been released concurrently (so it is fine)
|
|
}
|
|
} else {
|
|
// remove went okay, all is fine
|
|
}
|
|
}
|
|
l.mutex.Unlock()
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
// Initialize distributed lock.
|
|
func initDistributedNSLock(mux *router.Router, serverConfig serverCmdConfig) {
|
|
lockServers := newLockServers(serverConfig)
|
|
registerStorageLockers(mux, lockServers)
|
|
}
|
|
|
|
// Create one lock server for every local storage rpc server.
|
|
func newLockServers(serverConfig serverCmdConfig) (lockServers []*lockServer) {
|
|
// Initialize posix storage API.
|
|
exports := serverConfig.disks
|
|
ignoredExports := serverConfig.ignoredDisks
|
|
|
|
// Save ignored disks in a map
|
|
skipDisks := make(map[string]bool)
|
|
for _, ignoredExport := range ignoredExports {
|
|
skipDisks[ignoredExport] = true
|
|
}
|
|
for _, export := range exports {
|
|
if skipDisks[export] {
|
|
continue
|
|
}
|
|
if isLocalStorage(export) {
|
|
if idx := strings.LastIndex(export, ":"); idx != -1 {
|
|
export = export[idx+1:]
|
|
}
|
|
|
|
// Create handler for lock RPCs
|
|
locker := &lockServer{
|
|
rpcPath: export,
|
|
mutex: sync.Mutex{},
|
|
lockMap: make(map[string][]lockRequesterInfo),
|
|
timestamp: time.Now().UTC(),
|
|
}
|
|
|
|
// Start loop for stale lock maintenance
|
|
go func() {
|
|
// Start with random sleep time, so as to avoid "synchronous checks" between servers
|
|
time.Sleep(time.Duration(rand.Float64() * float64(lockMaintenanceLoop)))
|
|
for {
|
|
time.Sleep(lockMaintenanceLoop)
|
|
locker.lockMaintenance(lockCheckValidityInterval)
|
|
}
|
|
}()
|
|
|
|
lockServers = append(lockServers, locker)
|
|
}
|
|
}
|
|
return lockServers
|
|
}
|
|
|
|
// registerStorageLockers - register locker rpc handlers for net/rpc library clients
|
|
func registerStorageLockers(mux *router.Router, lockServers []*lockServer) {
|
|
for _, lockServer := range lockServers {
|
|
lockRPCServer := rpc.NewServer()
|
|
lockRPCServer.RegisterName("Dsync", lockServer)
|
|
lockRouter := mux.PathPrefix(reservedBucket).Subrouter()
|
|
lockRouter.Path(path.Join("/lock", lockServer.rpcPath)).Handler(lockRPCServer)
|
|
}
|
|
}
|
|
|