075b8903d7
This patch also reverts previous changes which were merged for migration to the newer disk format. We will be bringing these changes in subsequent releases. But we wish to add protection in this release such that future release migrations are protected. Revert "fs: Migration should handle bucketConfigs as regular objects. (#4482)" This reverts commit976870a391. Revert "fs: Migrate object metadata to objects directory. (#4195)" This reverts commit76f4f20609.
93 lines
2.4 KiB
Go
93 lines
2.4 KiB
Go
// +build !windows,!plan9,!solaris
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/*
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* Minio Cloud Storage, (C) 2016 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 lock
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import (
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"fmt"
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"os"
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"syscall"
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)
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// Internal function implements support for both
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// blocking and non blocking lock type.
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func lockedOpenFile(path string, flag int, perm os.FileMode, lockType int) (*LockedFile, error) {
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switch flag {
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case syscall.O_RDONLY:
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lockType |= syscall.LOCK_SH
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case syscall.O_WRONLY:
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fallthrough
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case syscall.O_RDWR:
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fallthrough
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case syscall.O_WRONLY | syscall.O_CREAT:
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fallthrough
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case syscall.O_RDWR | syscall.O_CREAT:
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lockType |= syscall.LOCK_EX
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default:
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return nil, fmt.Errorf("Unsupported flag (%d)", flag)
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}
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f, err := os.OpenFile(path, flag|syscall.O_SYNC, perm)
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if err != nil {
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return nil, err
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}
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if err = syscall.Flock(int(f.Fd()), lockType); err != nil {
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f.Close()
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if err == syscall.EWOULDBLOCK {
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err = ErrAlreadyLocked
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}
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return nil, err
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}
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st, err := os.Stat(path)
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if err != nil {
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f.Close()
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return nil, err
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}
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if st.IsDir() {
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f.Close()
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return nil, &os.PathError{
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Op: "open",
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Path: path,
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Err: syscall.EISDIR,
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}
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}
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return &LockedFile{File: f}, nil
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}
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// TryLockedOpenFile - tries a new write lock, functionality
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// it is similar to LockedOpenFile with with syscall.LOCK_EX
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// mode but along with syscall.LOCK_NB such that the function
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// doesn't wait forever but instead returns if it cannot
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// acquire a write lock.
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func TryLockedOpenFile(path string, flag int, perm os.FileMode) (*LockedFile, error) {
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return lockedOpenFile(path, flag, perm, syscall.LOCK_NB)
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}
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// LockedOpenFile - initializes a new lock and protects
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// the file from concurrent access across mount points.
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// This implementation doesn't support all the open
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// flags and shouldn't be considered as replacement
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// for os.OpenFile().
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func LockedOpenFile(path string, flag int, perm os.FileMode) (*LockedFile, error) {
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return lockedOpenFile(path, flag, perm, 0)
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}
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