6d5f2a4391
Better support of HEAD and listing of zero sized objects with trailing slash (a.k.a empty directory). For that, isLeafDir function is added to indicate if the specified object is an empty directory or not. Each backend (xl, fs) has the responsibility to store that information. Currently, in both of XL & FS, an empty directory is represented by an empty directory in the backend. isLeafDir() checks if the given path is an empty directory or not, since dir listing is costly if the latter contains too many objects, readDirN() is added in this PR to list only N number of entries. In isLeadDir(), we will only list one entry to check if a directory is empty or not.
117 lines
3.7 KiB
Go
117 lines
3.7 KiB
Go
/*
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* Minio Cloud Storage, (C) 2016, 2017 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 cmd
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import (
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"context"
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"path"
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"github.com/minio/minio/cmd/logger"
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)
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// getLoadBalancedDisks - fetches load balanced (sufficiently randomized) disk slice.
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func (xl xlObjects) getLoadBalancedDisks() (disks []StorageAPI) {
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// Based on the random shuffling return back randomized disks.
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for _, i := range hashOrder(UTCNow().String(), len(xl.getDisks())) {
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disks = append(disks, xl.getDisks()[i-1])
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}
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return disks
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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(ctx context.Context, 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 == "." || 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 true.
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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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// isObject - returns `true` if the prefix is an object i.e if
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// `xl.json` exists at the leaf, false otherwise.
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func (xl xlObjects) isObject(bucket, prefix string) (ok bool) {
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for _, disk := range xl.getLoadBalancedDisks() {
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if disk == nil {
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continue
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}
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// Check if 'prefix' is an object on this 'disk', else continue the check the next disk
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_, err := disk.StatFile(bucket, path.Join(prefix, xlMetaJSONFile))
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if err == nil {
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return true
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}
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// Ignore for file not found, disk not found or faulty disk.
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if IsErrIgnored(err, xlTreeWalkIgnoredErrs...) {
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continue
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}
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reqInfo := &logger.ReqInfo{BucketName: bucket}
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reqInfo.AppendTags("prefix", prefix)
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reqInfo.AppendTags("xlMetaJSONFile", xlMetaJSONFile)
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ctx := logger.SetReqInfo(context.Background(), reqInfo)
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logger.LogIf(ctx, err)
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} // Exhausted all disks - return false.
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return false
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}
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// isObjectDir returns if the specified path represents an empty directory.
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func (xl xlObjects) isObjectDir(bucket, prefix string) (ok bool) {
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for _, disk := range xl.getLoadBalancedDisks() {
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if disk == nil {
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continue
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}
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// Check if 'prefix' is an object on this 'disk', else continue the check the next disk
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ctnts, err := disk.ListDir(bucket, prefix, 1)
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if err == nil {
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if len(ctnts) == 0 {
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return true
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}
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return false
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}
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// Ignore for file not found, disk not found or faulty disk.
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if IsErrIgnored(err, xlTreeWalkIgnoredErrs...) {
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continue
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}
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reqInfo := &logger.ReqInfo{BucketName: bucket}
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reqInfo.AppendTags("prefix", prefix)
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ctx := logger.SetReqInfo(context.Background(), reqInfo)
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logger.LogIf(ctx, err)
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} // Exhausted all disks - return false.
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return false
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}
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// Calculate the space occupied by an object in a single disk
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func (xl xlObjects) sizeOnDisk(fileSize int64, blockSize int64, dataBlocks int) int64 {
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numBlocks := fileSize / blockSize
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chunkSize := ceilFrac(blockSize, int64(dataBlocks))
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sizeInDisk := numBlocks * chunkSize
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remaining := fileSize % blockSize
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if remaining > 0 {
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sizeInDisk += ceilFrac(remaining, int64(dataBlocks))
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}
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return sizeInDisk
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}
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