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af4f82228c
Windows requires this lock to be released before the directory is renamed. But on unix-like operating systems, releasing the lock and trying to reacquire it immediately can be flaky if a process is forked around the same time. The file descriptors are marked as close-on-exec by the Go runtime, but there is a window between the fork and exec where another process will be holding the lock.
39 lines
1.3 KiB
Go
39 lines
1.3 KiB
Go
// Copyright 2016 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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// +build !windows
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package wal
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import "os"
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func (w *WAL) renameWal(tmpdirpath string) (*WAL, error) {
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// On non-Windows platforms, hold the lock while renaming. Releasing
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// the lock and trying to reacquire it quickly can be flaky because
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// it's possible the process will fork to spawn a process while this is
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// happening. The fds are set up as close-on-exec by the Go runtime,
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// but there is a window between the fork and the exec where another
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// process holds the lock.
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if err := os.RemoveAll(w.dir); err != nil {
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return nil, err
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}
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if err := os.Rename(tmpdirpath, w.dir); err != nil {
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return nil, err
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}
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w.fp = newFilePipeline(w.dir, SegmentSizeBytes)
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return w, nil
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}
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