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ccf477d12b
Currently the max size of each WAL entry is hard coded as 10MB. If users set a value > 10MB for the flag --max-request-bytes, then etcd may run into a situation that it successfully processes a big request, but fails to decode it when replaying the WAL file on startup. On the other hand, we can't just remove the limitation, because if a WAL entry is somehow corrupted, and its recByte is a huge value, then etcd may run out of memory. So the solution is to restrict the max size of each WAL entry as a dynamic value, which is the remaining size of the WAL file. Signed-off-by: Benjamin Wang <wachao@vmware.com>
116 lines
3.2 KiB
Go
116 lines
3.2 KiB
Go
// Copyright 2015 The etcd Authors
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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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package wal
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import (
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"io"
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"os"
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"path/filepath"
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"time"
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"go.etcd.io/etcd/client/pkg/v3/fileutil"
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"go.etcd.io/etcd/server/v3/storage/wal/walpb"
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"go.uber.org/zap"
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)
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// Repair tries to repair ErrUnexpectedEOF in the
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// last wal file by truncating.
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func Repair(lg *zap.Logger, dirpath string) bool {
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if lg == nil {
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lg = zap.NewNop()
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}
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f, err := openLast(lg, dirpath)
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if err != nil {
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return false
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}
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defer f.Close()
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lg.Info("repairing", zap.String("path", f.Name()))
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rec := &walpb.Record{}
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decoder := newDecoder(fileutil.NewFileReader(f.File))
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for {
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lastOffset := decoder.lastOffset()
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err := decoder.decode(rec)
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switch err {
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case nil:
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// update crc of the decoder when necessary
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switch rec.Type {
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case crcType:
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crc := decoder.crc.Sum32()
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// current crc of decoder must match the crc of the record.
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// do no need to match 0 crc, since the decoder is a new one at this case.
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if crc != 0 && rec.Validate(crc) != nil {
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return false
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}
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decoder.updateCRC(rec.Crc)
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}
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continue
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case io.EOF:
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lg.Info("repaired", zap.String("path", f.Name()), zap.Error(io.EOF))
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return true
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case io.ErrUnexpectedEOF:
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brokenName := f.Name() + ".broken"
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bf, bferr := os.Create(brokenName)
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if bferr != nil {
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lg.Warn("failed to create backup file", zap.String("path", brokenName), zap.Error(bferr))
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return false
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}
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defer bf.Close()
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if _, err = f.Seek(0, io.SeekStart); err != nil {
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lg.Warn("failed to read file", zap.String("path", f.Name()), zap.Error(err))
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return false
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}
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if _, err = io.Copy(bf, f); err != nil {
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lg.Warn("failed to copy", zap.String("from", f.Name()), zap.String("to", brokenName), zap.Error(err))
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return false
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}
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if err = f.Truncate(lastOffset); err != nil {
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lg.Warn("failed to truncate", zap.String("path", f.Name()), zap.Error(err))
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return false
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}
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start := time.Now()
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if err = fileutil.Fsync(f.File); err != nil {
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lg.Warn("failed to fsync", zap.String("path", f.Name()), zap.Error(err))
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return false
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}
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walFsyncSec.Observe(time.Since(start).Seconds())
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lg.Info("repaired", zap.String("path", f.Name()), zap.Error(io.ErrUnexpectedEOF))
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return true
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default:
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lg.Warn("failed to repair", zap.String("path", f.Name()), zap.Error(err))
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return false
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}
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}
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}
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// openLast opens the last wal file for read and write.
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func openLast(lg *zap.Logger, dirpath string) (*fileutil.LockedFile, error) {
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names, err := readWALNames(lg, dirpath)
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if err != nil {
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return nil, err
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}
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last := filepath.Join(dirpath, names[len(names)-1])
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return fileutil.LockFile(last, os.O_RDWR, fileutil.PrivateFileMode)
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}
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