forked from juicedata/juicefs
/
tkv_lock.go
253 lines (237 loc) · 5.44 KB
/
tkv_lock.go
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/*
* JuiceFS, Copyright 2021 leonatone, 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 meta
import (
"context"
"syscall"
"time"
"github.com/leonatone/juicefs/pkg/utils"
)
type lockOwner struct {
sid uint64
owner uint64
}
func marshalFlock(ls map[lockOwner]byte) []byte {
b := utils.NewBuffer(uint32(len(ls)) * 17)
for o, l := range ls {
b.Put64(o.sid)
b.Put64(o.owner)
b.Put8(l)
}
return b.Bytes()
}
func unmarshalFlock(buf []byte) map[lockOwner]byte {
b := utils.FromBuffer(buf)
var ls = make(map[lockOwner]byte)
for b.HasMore() {
sid := b.Get64()
owner := b.Get64()
ltype := b.Get8()
ls[lockOwner{sid, owner}] = ltype
}
return ls
}
func (m *kvMeta) Flock(ctx Context, inode Ino, owner uint64, ltype uint32, block bool) syscall.Errno {
ikey := m.flockKey(inode)
var err error
lkey := lockOwner{m.sid, owner}
for {
err = m.txn(func(tx *kvTxn) error {
v := tx.get(ikey)
ls := unmarshalFlock(v)
switch ltype {
case F_UNLCK:
delete(ls, lkey)
case F_RDLCK:
for o, l := range ls {
if l == 'W' && o != lkey {
return syscall.EAGAIN
}
}
ls[lkey] = 'R'
case F_WRLCK:
delete(ls, lkey)
if len(ls) > 0 {
return syscall.EAGAIN
}
ls[lkey] = 'W'
default:
return syscall.EINVAL
}
if len(ls) == 0 {
tx.delete(ikey)
} else {
tx.set(ikey, marshalFlock(ls))
}
return nil
}, inode)
if !block || err != syscall.EAGAIN {
break
}
if ltype == F_WRLCK {
time.Sleep(time.Millisecond * 1)
} else {
time.Sleep(time.Millisecond * 10)
}
if ctx.Canceled() {
return syscall.EINTR
}
}
return errno(err)
}
func marshalPlock(ls map[lockOwner][]byte) []byte {
var size uint32
for _, l := range ls {
size += 8 + 8 + 4 + uint32(len(l))
}
b := utils.NewBuffer(size)
for k, records := range ls {
b.Put64(k.sid)
b.Put64(k.owner)
b.Put32(uint32(len(records)))
b.Put(records)
}
return b.Bytes()
}
func unmarshalPlock(buf []byte) map[lockOwner][]byte {
b := utils.FromBuffer(buf)
var ls = make(map[lockOwner][]byte)
for b.HasMore() {
sid := b.Get64()
owner := b.Get64()
records := b.Get(int(b.Get32()))
ls[lockOwner{sid, owner}] = records
}
return ls
}
func (m *kvMeta) Getlk(ctx Context, inode Ino, owner uint64, ltype *uint32, start, end *uint64, pid *uint32) syscall.Errno {
if *ltype == F_UNLCK {
*start = 0
*end = 0
*pid = 0
return 0
}
v, err := m.get(m.plockKey(inode))
if err != nil {
return errno(err)
}
owners := unmarshalPlock(v)
delete(owners, lockOwner{m.sid, owner})
for o, records := range owners {
ls := loadLocks(records)
for _, l := range ls {
// find conflicted locks
if (*ltype == F_WRLCK || l.Type == F_WRLCK) && *end >= l.Start && *start <= l.End {
*ltype = l.Type
*start = l.Start
*end = l.End
if o.sid == m.sid {
*pid = l.Pid
} else {
*pid = 0
}
return 0
}
}
}
*ltype = F_UNLCK
*start = 0
*end = 0
*pid = 0
return 0
}
func (m *kvMeta) Setlk(ctx Context, inode Ino, owner uint64, block bool, ltype uint32, start, end uint64, pid uint32) syscall.Errno {
ikey := m.plockKey(inode)
var err error
lock := plockRecord{ltype, pid, start, end}
lkey := lockOwner{m.sid, owner}
for {
err = m.txn(func(tx *kvTxn) error {
owners := unmarshalPlock(tx.get(ikey))
if ltype == F_UNLCK {
records := owners[lkey]
ls := loadLocks(records)
if len(ls) == 0 {
return nil // change nothing
}
ls = updateLocks(ls, lock)
if len(ls) == 0 {
delete(owners, lkey)
} else {
owners[lkey] = dumpLocks(ls)
}
} else {
ls := loadLocks(owners[lkey])
delete(owners, lkey)
for _, d := range owners {
ls := loadLocks(d)
for _, l := range ls {
// find conflicted locks
if (ltype == F_WRLCK || l.Type == F_WRLCK) && end >= l.Start && start <= l.End {
return syscall.EAGAIN
}
}
}
ls = updateLocks(ls, lock)
owners[lkey] = dumpLocks(ls)
}
if len(owners) == 0 {
tx.delete(ikey)
} else {
tx.set(ikey, marshalPlock(owners))
}
return nil
}, inode)
if !block || err != syscall.EAGAIN {
break
}
if ltype == F_WRLCK {
time.Sleep(time.Millisecond * 1)
} else {
time.Sleep(time.Millisecond * 10)
}
if ctx.Canceled() {
return syscall.EINTR
}
}
return errno(err)
}
func (m *kvMeta) ListLocks(ctx context.Context, inode Ino) ([]PLockItem, []FLockItem, error) {
fKey := m.flockKey(inode)
pKey := m.plockKey(inode)
var flocks []FLockItem
var plocks []PLockItem
fv, err := m.get(fKey)
if err != nil {
return nil, nil, err
}
fs := unmarshalFlock(fv)
for k, t := range fs {
flocks = append(flocks, FLockItem{ownerKey{k.sid, k.owner}, string(t)})
}
pv, err := m.get(pKey)
if err != nil {
return nil, nil, err
}
owners := unmarshalPlock(pv)
for k, records := range owners {
ls := loadLocks(records)
for _, l := range ls {
plocks = append(plocks, PLockItem{ownerKey{k.sid, k.owner}, l})
}
}
return plocks, flocks, nil
}