mirror of https://github.com/minio/minio.git
106 lines
3.6 KiB
Go
106 lines
3.6 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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"context"
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"errors"
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"path"
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"time"
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"github.com/minio/minio/cmd/logger"
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)
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const lockRESTVersion = "v1"
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const lockRESTPath = minioReservedBucketPath + "/lock/" + lockRESTVersion
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var lockServicePath = path.Join(minioReservedBucketPath, lockServiceSubPath)
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const (
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lockRESTMethodLock = "lock"
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lockRESTMethodRLock = "rlock"
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lockRESTMethodUnlock = "unlock"
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lockRESTMethodRUnlock = "runlock"
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lockRESTMethodForceUnlock = "forceunlock"
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lockRESTMethodExpired = "expired"
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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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type lockResponse struct {
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Success bool
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}
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// Similar to removeEntry but only removes an entry only if the lock entry exists in map.
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func (l *localLocker) removeEntryIfExists(nlrip nameLockRequesterInfoPair) {
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// Check if entry is still in map (could have been removed altogether by 'concurrent' (R)Unlock of last entry)
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if lri, ok := l.lockMap[nlrip.name]; ok {
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if !l.removeEntry(nlrip.name, nlrip.lri.UID, &lri) {
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// Remove failed, in case it is a:
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if nlrip.lri.Writer {
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// Writer: this should never happen as the whole (mapped) entry should have been deleted
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reqInfo := (&logger.ReqInfo{}).AppendTags("name", nlrip.name)
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reqInfo.AppendTags("uid", nlrip.lri.UID)
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ctx := logger.SetReqInfo(context.Background(), reqInfo)
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logger.LogIf(ctx, errors.New("Lock maintenance failed to remove entry for write lock (should never happen)"))
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} // Reader: this can happen if multiple read locks were active and
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// the one we are looking for has been released concurrently (so it is fine).
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} // Removal went okay, all is fine.
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}
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}
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// removeEntry either, based on the uid of the lock message, removes a single entry from the
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// lockRequesterInfo array or the whole array from the map (in case of a write lock or last read lock)
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func (l *localLocker) removeEntry(name, uid string, lri *[]lockRequesterInfo) bool {
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// Find correct entry to remove based on uid.
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for index, entry := range *lri {
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if entry.UID == uid {
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if len(*lri) == 1 {
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// Remove the (last) lock.
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delete(l.lockMap, name)
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} else {
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// Remove the appropriate read lock.
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*lri = append((*lri)[:index], (*lri)[index+1:]...)
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l.lockMap[name] = *lri
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}
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return true
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}
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}
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// None found return false, perhaps entry removed in previous run.
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return false
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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(m map[string][]lockRequesterInfo, interval time.Duration) []nameLockRequesterInfoPair {
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rslt := []nameLockRequesterInfoPair{}
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for name, lriArray := range m {
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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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rslt = append(rslt, nameLockRequesterInfoPair{name: name, lri: lriArray[idx]})
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lriArray[idx].TimeLastCheck = UTCNow()
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}
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}
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}
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return rslt
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}
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