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minio/cmd/lock-rest-server-common.go

109 lines
3.7 KiB

/*
* MinIO Cloud Storage, (C) 2019 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 (
"errors"
"path"
"time"
)
const lockRESTVersion = "v2"
const lockRESTPath = minioReservedBucketPath + "/lock/" + lockRESTVersion
var lockServicePath = path.Join(minioReservedBucketPath, lockServiceSubPath)
const (
lockRESTMethodLock = "lock"
lockRESTMethodRLock = "rlock"
lockRESTMethodUnlock = "unlock"
lockRESTMethodRUnlock = "runlock"
lockRESTMethodForceUnlock = "forceunlock"
lockRESTMethodExpired = "expired"
// Unique ID of lock/unlock request.
lockRESTUID = "uid"
// Source contains the line number, function and file name of the code
// on the client node that requested the lock.
lockRESTSource = "source"
// Resource contains a entity to be locked/unlocked.
lockRESTResource = "resource"
// ServerAddr contains the address of the server who requested lock/unlock of the above resource.
lockRESTServerAddr = "serverAddr"
// ServiceEndpoint contains the network path of above server to do lock/unlock.
lockRESTServerEndpoint = "serverEndpoint"
)
// nameLockRequesterInfoPair is a helper type for lock maintenance
type nameLockRequesterInfoPair struct {
name string
lri lockRequesterInfo
}
var errLockConflict = errors.New("lock conflict")
var errLockNotExpired = errors.New("lock not expired")
// Similar to removeEntry but only removes an entry only if the lock entry exists in map.
func (l *localLocker) removeEntryIfExists(nlrip nameLockRequesterInfoPair) {
// 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 {
// Even if the entry exists, it may not be the same entry which was
// considered as expired, so we simply an attempt to remove it if its
// not possible there is nothing we need to do.
l.removeEntry(nlrip.name, nlrip.lri.UID, &lri)
}
}
// removeEntry 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 *localLocker) 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 {
// Remove the write lock.
delete(l.lockMap, name)
} else {
// Remove the appropriate read lock.
*lri = append((*lri)[:index], (*lri)[index+1:]...)
l.lockMap[name] = *lri
}
return true
}
}
// None found return false, perhaps entry removed in previous run.
return false
}
// 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 = UTCNow()
}
}
}
return rslt
}