minio/cmd/shared-lock.go
Anis Elleuch d6d01067a0
fix: allow global leader lock context merge to be canceled (#16603)
Global leader lock was first designated to only acquired once
until the node is killed. However, currently, the code acquires
it repeatedly during the lifetime of the server, now there is a
goroutine leak.
2023-02-13 01:26:38 -08:00

88 lines
2.3 KiB
Go

// Copyright (c) 2015-2022 MinIO, Inc.
//
// This file is part of MinIO Object Storage stack
//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU Affero General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Affero General Public License for more details.
//
// You should have received a copy of the GNU Affero General Public License
// along with this program. If not, see <http://www.gnu.org/licenses/>.
package cmd
import (
"context"
"time"
)
var sharedLockTimeout = newDynamicTimeoutWithOpts(dynamicTimeoutOpts{
timeout: 30 * time.Second,
minimum: 10 * time.Second,
retryInterval: time.Minute,
})
type sharedLock struct {
lockContext chan LockContext
}
func (ld sharedLock) backgroundRoutine(ctx context.Context, objAPI ObjectLayer, lockName string) {
for {
locker := objAPI.NewNSLock(minioMetaBucket, lockName)
lkctx, err := locker.GetLock(ctx, sharedLockTimeout)
if err != nil {
continue
}
keepLock:
for {
select {
case <-ctx.Done():
return
case <-lkctx.Context().Done():
// The context of the lock is canceled, this can happen
// if one lock lost quorum due to cluster instability
// in that case, try to lock again.
break keepLock
case ld.lockContext <- lkctx:
// Send the lock context to anyone asking for it
}
}
}
}
func mergeContext(ctx1, ctx2 context.Context) (context.Context, context.CancelFunc) {
ctx, cancel := context.WithCancel(context.Background())
go func() {
select {
case <-ctx1.Done():
case <-ctx2.Done():
// The lock acquirer decides to cancel, exit this goroutine
case <-ctx.Done():
}
cancel()
}()
return ctx, cancel
}
func (ld sharedLock) GetLock(ctx context.Context) (context.Context, context.CancelFunc) {
l := <-ld.lockContext
return mergeContext(l.Context(), ctx)
}
func newSharedLock(ctx context.Context, objAPI ObjectLayer, lockName string) *sharedLock {
l := &sharedLock{
lockContext: make(chan LockContext),
}
go l.backgroundRoutine(ctx, objAPI, lockName)
return l
}