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112 lines
3.1 KiB
112 lines
3.1 KiB
/*
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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 main
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import (
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"math/rand"
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"path"
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"sync"
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"time"
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)
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// getRandomDisk - gives a random disk at any point in time from the
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// available pool of disks.
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func (xl xlObjects) getRandomDisk() (disk StorageAPI) {
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rand.Seed(time.Now().UTC().UnixNano()) // Seed with current time.
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randIndex := rand.Intn(len(xl.storageDisks) - 1)
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disk = xl.storageDisks[randIndex] // Pick a random disk.
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return disk
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}
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// This function does the following check, suppose
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// object is "a/b/c/d", stat makes sure that objects ""a/b/c""
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// "a/b" and "a" do not exist.
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func (xl xlObjects) parentDirIsObject(bucket, parent string) bool {
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var isParentDirObject func(string) bool
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isParentDirObject = func(p string) bool {
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if p == "." {
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return false
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}
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if xl.isObject(bucket, p) {
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// If there is already a file at prefix "p" return error.
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return true
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}
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// Check if there is a file as one of the parent paths.
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return isParentDirObject(path.Dir(p))
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}
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return isParentDirObject(parent)
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}
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func (xl xlObjects) isObject(bucket, prefix string) bool {
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// Create errs and volInfo slices of storageDisks size.
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var errs = make([]error, len(xl.storageDisks))
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// Allocate a new waitgroup.
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var wg = &sync.WaitGroup{}
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for index, disk := range xl.storageDisks {
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wg.Add(1)
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// Stat file on all the disks in a routine.
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go func(index int, disk StorageAPI) {
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defer wg.Done()
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_, err := disk.StatFile(bucket, path.Join(prefix, xlMetaJSONFile))
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if err != nil {
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errs[index] = err
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return
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}
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errs[index] = nil
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}(index, disk)
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}
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// Wait for all the Stat operations to finish.
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wg.Wait()
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var errFileNotFoundCount int
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for _, err := range errs {
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if err != nil {
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if err == errFileNotFound {
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errFileNotFoundCount++
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// If we have errors with file not found greater than allowed read
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// quorum we return err as errFileNotFound.
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if errFileNotFoundCount > len(xl.storageDisks)-xl.readQuorum {
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return false
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}
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continue
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}
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errorIf(err, "Unable to access file "+path.Join(bucket, prefix))
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return false
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}
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}
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return true
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}
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// statPart - stat a part file.
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func (xl xlObjects) statPart(bucket, objectPart string) (fileInfo FileInfo, err error) {
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// Count for errors encountered.
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var xlJSONErrCount = 0
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// Return the first success entry based on the selected random disk.
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for xlJSONErrCount < len(xl.storageDisks) {
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// Choose a random disk on each attempt.
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disk := xl.getRandomDisk()
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fileInfo, err = disk.StatFile(bucket, objectPart)
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if err == nil {
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return fileInfo, nil
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}
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xlJSONErrCount++ // Update error count.
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}
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return FileInfo{}, err
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}
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