/*

* Minio Cloud Storage, (C) 2016, 2017 Minio, Inc.

*

* Licensed under the Apache License, Version 2.0 (the "License");

* you may not use this file except in compliance with the License.

* You may obtain a copy of the License at

*

* http://www.apache.org/licenses/LICENSE-2.0

*

* Unless required by applicable law or agreed to in writing, software

* distributed under the License is distributed on an "AS IS" BASIS,

* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

* See the License for the specific language governing permissions and

* limitations under the License.

*/

package cmd

import (

"crypto/md5"

"encoding/hex"

"fmt"

"hash"

"io"

"io/ioutil"

"os"

"path"

"path/filepath"

"sort"

"syscall"

"github.com/minio/minio/pkg/lock"

"github.com/minio/sha256-simd"

)

// fsObjects - Implements fs object layer.

type fsObjects struct {

// Path to be exported over S3 API.

fsPath string

// Unique value to be used for all

// temporary transactions.

fsUUID string

// This value shouldn't be touched, once initialized.

fsFormatRlk *lock.RLockedFile // Is a read lock on `format.json`.

// FS rw pool.

rwPool *fsIOPool

// ListObjects pool management.

listPool *treeWalkPool

// To manage the appendRoutine go0routines

bgAppend *backgroundAppend

}

// Initializes meta volume on all the fs path.

func initMetaVolumeFS(fsPath, fsUUID string) error {

// This happens for the first time, but keep this here since this

// is the only place where it can be made less expensive

// optimizing all other calls. Create minio meta volume,

// if it doesn't exist yet.

metaBucketPath := pathJoin(fsPath, minioMetaBucket)

if err := mkdirAll(metaBucketPath, 0777); err != nil {

return err

}

metaTmpPath := pathJoin(fsPath, minioMetaTmpBucket, fsUUID)

if err := mkdirAll(metaTmpPath, 0777); err != nil {

return err

}

metaMultipartPath := pathJoin(fsPath, minioMetaMultipartBucket)

return mkdirAll(metaMultipartPath, 0777)

}

// newFSObjectLayer - initialize new fs object layer.

func newFSObjectLayer(fsPath string) (ObjectLayer, error) {

if fsPath == "" {

return nil, errInvalidArgument

}

var err error

// Disallow relative paths, figure out absolute paths.

fsPath, err = filepath.Abs(fsPath)

if err != nil {

return nil, err

}

fi, err := osStat(preparePath(fsPath))

if err == nil {

if !fi.IsDir() {

return nil, syscall.ENOTDIR

}

}

if os.IsNotExist(err) {

// Disk not found create it.

err = mkdirAll(fsPath, 0777)

if err != nil {

return nil, err

}

}

di, err := getDiskInfo(preparePath(fsPath))

if err != nil {

return nil, err

}

// Check if disk has minimum required total space.

if err = checkDiskMinTotal(di); err != nil {

return nil, err

}

// Assign a new UUID for FS minio mode. Each server instance

// gets its own UUID for temporary file transaction.

fsUUID := mustGetUUID()

// Initialize meta volume, if volume already exists ignores it.

if err = initMetaVolumeFS(fsPath, fsUUID); err != nil {

return nil, fmt.Errorf("Unable to initialize '.minio.sys' meta volume, %s", err)

}

// Initialize `format.json`, this function also returns.

rlk, err := initFormatFS(fsPath)

if err != nil {

return nil, err

}

// Initialize fs objects.

fs := &fsObjects{

fsPath: fsPath,

fsUUID: fsUUID,

rwPool: &fsIOPool{

readersMap: make(map[string]*lock.RLockedFile),

},

listPool: newTreeWalkPool(globalLookupTimeout),

bgAppend: &backgroundAppend{

infoMap: make(map[string]bgAppendPartsInfo),

},

}

// Once the filesystem has initialized hold the read lock for

// the life time of the server. This is done to ensure that under

// shared backend mode for FS, remote servers do not migrate

// or cause changes on backend format.

fs.fsFormatRlk = rlk

// Initialize and load bucket policies.

if err = initBucketPolicies(fs); err != nil {

return nil, fmt.Errorf("Unable to load all bucket policies. %s", err)

}

// Initialize a new event notifier.

if err = initEventNotifier(fs); err != nil {

return nil, fmt.Errorf("Unable to initialize event notification. %s", err)

}

// Return successfully initialized object layer.

return fs, nil

}

// Should be called when process shuts down.

func (fs fsObjects) Shutdown() error {

// Cleanup and delete tmp uuid.

return fsRemoveAll(pathJoin(fs.fsPath, minioMetaTmpBucket, fs.fsUUID))

}

// StorageInfo - returns underlying storage statistics.

func (fs fsObjects) StorageInfo() StorageInfo {

info, err := getDiskInfo(preparePath(fs.fsPath))

errorIf(err, "Unable to get disk info %#v", fs.fsPath)

storageInfo := StorageInfo{

Total: info.Total,

Free: info.Free,

}

storageInfo.Backend.Type = FS

return storageInfo

}

/// Bucket operations

// getBucketDir - will convert incoming bucket names to

// corresponding valid bucket names on the backend in a platform

// compatible way for all operating systems.

func (fs fsObjects) getBucketDir(bucket string) (string, error) {

// Verify if bucket is valid.

if !IsValidBucketName(bucket) {

return "", traceError(BucketNameInvalid{Bucket: bucket})

}

bucketDir := pathJoin(fs.fsPath, bucket)

return bucketDir, nil

}

func (fs fsObjects) statBucketDir(bucket string) (os.FileInfo, error) {

bucketDir, err := fs.getBucketDir(bucket)

if err != nil {

return nil, err

}

st, err := fsStatDir(bucketDir)

if err != nil {

return nil, err

}

return st, nil

}

// MakeBucket - create a new bucket, returns if it

// already exists.

func (fs fsObjects) MakeBucketWithLocation(bucket, location string) error {

bucketDir, err := fs.getBucketDir(bucket)

if err != nil {

return toObjectErr(err, bucket)

}

if err = fsMkdir(bucketDir); err != nil {

return toObjectErr(err, bucket)

}

return nil

}

// GetBucketInfo - fetch bucket metadata info.

func (fs fsObjects) GetBucketInfo(bucket string) (bi BucketInfo, e error) {

st, err := fs.statBucketDir(bucket)

if err != nil {

return bi, toObjectErr(err, bucket)

}

// As osStat() doesn't carry other than ModTime(), use ModTime() as CreatedTime.

createdTime := st.ModTime()

return BucketInfo{

Name: bucket,

Created: createdTime,

}, nil

}

// ListBuckets - list all s3 compatible buckets (directories) at fsPath.

func (fs fsObjects) ListBuckets() ([]BucketInfo, error) {

if err := checkPathLength(fs.fsPath); err != nil {

return nil, traceError(err)

}

var bucketInfos []BucketInfo

entries, err := readDir(preparePath(fs.fsPath))

if err != nil {

return nil, toObjectErr(traceError(errDiskNotFound))

}

for _, entry := range entries {

// Ignore all reserved bucket names and invalid bucket names.

if isReservedOrInvalidBucket(entry) {

continue

}

var fi os.FileInfo

fi, err = fsStatDir(pathJoin(fs.fsPath, entry))

if err != nil {

// If the directory does not exist, skip the entry.

if errorCause(err) == errVolumeNotFound {

continue

} else if errorCause(err) == errVolumeAccessDenied {

// Skip the entry if its a file.

continue

}

return nil, err

}

bucketInfos = append(bucketInfos, BucketInfo{

Name: fi.Name(),

// As osStat() doesnt carry CreatedTime, use ModTime() as CreatedTime.

Created: fi.ModTime(),

})

}

// Sort bucket infos by bucket name.

sort.Sort(byBucketName(bucketInfos))

// Succes.

return bucketInfos, nil

}

// DeleteBucket - delete a bucket and all the metadata associated

// with the bucket including pending multipart, object metadata.

func (fs fsObjects) DeleteBucket(bucket string) error {

bucketDir, err := fs.getBucketDir(bucket)

if err != nil {

return toObjectErr(err, bucket)

}

// Attempt to delete regular bucket.

if err = fsRemoveDir(bucketDir); err != nil {

return toObjectErr(err, bucket)

}

// Cleanup all the previously incomplete multiparts.

minioMetaMultipartBucketDir := pathJoin(fs.fsPath, minioMetaMultipartBucket, bucket)

if err = fsRemoveAll(minioMetaMultipartBucketDir); err != nil {

return toObjectErr(err, bucket)

}

// Cleanup all the bucket metadata.

minioMetadataBucketDir := pathJoin(fs.fsPath, minioMetaBucket, bucketMetaPrefix, bucket)

if err = fsRemoveAll(minioMetadataBucketDir); err != nil {

return toObjectErr(err, bucket)

}

return nil

}

/// Object Operations

// CopyObject - copy object source object to destination object.

// if source object and destination object are same we only

// update metadata.

func (fs fsObjects) CopyObject(srcBucket, srcObject, dstBucket, dstObject string, metadata map[string]string) (oi ObjectInfo, e error) {

if _, err := fs.statBucketDir(srcBucket); err != nil {

return oi, toObjectErr(err, srcBucket)

}

// Stat the file to get file size.

fi, err := fsStatFile(pathJoin(fs.fsPath, srcBucket, srcObject))

if err != nil {

return oi, toObjectErr(err, srcBucket, srcObject)

}

// Check if this request is only metadata update.

cpMetadataOnly := isStringEqual(pathJoin(srcBucket, srcObject), pathJoin(dstBucket, dstObject))

if cpMetadataOnly {

fsMetaPath := pathJoin(fs.fsPath, minioMetaBucket, bucketMetaPrefix, srcBucket, srcObject, fsMetaJSONFile)

var wlk *lock.LockedFile

wlk, err = fs.rwPool.Write(fsMetaPath)

if err != nil {

return oi, toObjectErr(traceError(err), srcBucket, srcObject)

}

// This close will allow for locks to be synchronized on `fs.json`.

defer wlk.Close()

// Save objects' metadata in `fs.json`.

fsMeta := newFSMetaV1()

fsMeta.Meta = metadata

if _, err = fsMeta.WriteTo(wlk); err != nil {

return oi, toObjectErr(err, srcBucket, srcObject)

}

// Return the new object info.

return fsMeta.ToObjectInfo(srcBucket, srcObject, fi), nil

}

// Length of the file to read.

length := fi.Size()

// Initialize pipe.

pipeReader, pipeWriter := io.Pipe()

go func() {

var startOffset int64 // Read the whole file.

if gerr := fs.GetObject(srcBucket, srcObject, startOffset, length, pipeWriter); gerr != nil {

errorIf(gerr, "Unable to read %s/%s.", srcBucket, srcObject)

pipeWriter.CloseWithError(gerr)

return

}

pipeWriter.Close() // Close writer explicitly signalling we wrote all data.

}()

objInfo, err := fs.PutObject(dstBucket, dstObject, length, pipeReader, metadata, "")

if err != nil {

return oi, toObjectErr(err, dstBucket, dstObject)

}

// Explicitly close the reader.

pipeReader.Close()

return objInfo, nil

}

// GetObject - reads an object from the disk.

// Supports additional parameters like offset and length

// which are synonymous with HTTP Range requests.

//

// startOffset indicates the starting read location of the object.

// length indicates the total length of the object.

func (fs fsObjects) GetObject(bucket, object string, offset int64, length int64, writer io.Writer) (err error) {

if err = checkGetObjArgs(bucket, object); err != nil {

return err

}

if _, err = fs.statBucketDir(bucket); err != nil {

return toObjectErr(err, bucket)

}

// Offset cannot be negative.

if offset < 0 {

return toObjectErr(traceError(errUnexpected), bucket, object)

}

// Writer cannot be nil.

if writer == nil {

return toObjectErr(traceError(errUnexpected), bucket, object)

}

if bucket != minioMetaBucket {

fsMetaPath := pathJoin(fs.fsPath, minioMetaBucket, bucketMetaPrefix, bucket, object, fsMetaJSONFile)

_, err = fs.rwPool.Open(fsMetaPath)

if err != nil && err != errFileNotFound {

return toObjectErr(traceError(err), bucket, object)

}

defer fs.rwPool.Close(fsMetaPath)

}

// Read the object, doesn't exist returns an s3 compatible error.

fsObjPath := pathJoin(fs.fsPath, bucket, object)

reader, size, err := fsOpenFile(fsObjPath, offset)

if err != nil {

return toObjectErr(err, bucket, object)

}

defer reader.Close()

bufSize := int64(readSizeV1)

if length > 0 && bufSize > length {

bufSize = length

}

// For negative length we read everything.

if length < 0 {

length = size - offset

}

// Reply back invalid range if the input offset and length fall out of range.

if offset > size || offset+length > size {

return traceError(InvalidRange{offset, length, size})

}

// Allocate a staging buffer.

buf := make([]byte, int(bufSize))

_, err = io.CopyBuffer(writer, io.LimitReader(reader, length), buf)

return toObjectErr(traceError(err), bucket, object)

}

// getObjectInfo - wrapper for reading object metadata and constructs ObjectInfo.

func (fs fsObjects) getObjectInfo(bucket, object string) (oi ObjectInfo, e error) {

fsMeta := fsMetaV1{}

fsMetaPath := pathJoin(fs.fsPath, minioMetaBucket, bucketMetaPrefix, bucket, object, fsMetaJSONFile)

// Read `fs.json` to perhaps contend with

// parallel Put() operations.

rlk, err := fs.rwPool.Open(fsMetaPath)

if err == nil {

// Read from fs metadata only if it exists.

defer fs.rwPool.Close(fsMetaPath)

if _, rerr := fsMeta.ReadFrom(rlk.LockedFile); rerr != nil {

// `fs.json` can be empty due to previously failed

// PutObject() transaction, if we arrive at such

// a situation we just ignore and continue.

if errorCause(rerr) != io.EOF {

return oi, toObjectErr(rerr, bucket, object)

}

}

}

// Ignore if `fs.json` is not available, this is true for pre-existing data.

if err != nil && err != errFileNotFound {

return oi, toObjectErr(traceError(err), bucket, object)

}

// Stat the file to get file size.

fi, err := fsStatFile(pathJoin(fs.fsPath, bucket, object))

if err != nil {

return oi, toObjectErr(err, bucket, object)

}

return fsMeta.ToObjectInfo(bucket, object, fi), nil

}

// GetObjectInfo - reads object metadata and replies back ObjectInfo.

func (fs fsObjects) GetObjectInfo(bucket, object string) (oi ObjectInfo, e error) {

if err := checkGetObjArgs(bucket, object); err != nil {

return oi, err

}

if _, err := fs.statBucketDir(bucket); err != nil {

return oi, toObjectErr(err, bucket)

}

return fs.getObjectInfo(bucket, object)

}

// This function does the following check, suppose

// object is "a/b/c/d", stat makes sure that objects ""a/b/c""

// "a/b" and "a" do not exist.

func (fs fsObjects) parentDirIsObject(bucket, parent string) bool {

var isParentDirObject func(string) bool

isParentDirObject = func(p string) bool {

if p == "." {

return false

}

if _, err := fsStatFile(pathJoin(fs.fsPath, bucket, p)); err == nil {

// If there is already a file at prefix "p" return error.

return true

}

// Check if there is a file as one of the parent paths.

return isParentDirObject(path.Dir(p))

}

return isParentDirObject(parent)

}

// PutObject - creates an object upon reading from the input stream

// until EOF, writes data directly to configured filesystem path.

// Additionally writes `fs.json` which carries the necessary metadata

// for future object operations.

func (fs fsObjects) PutObject(bucket string, object string, size int64, data io.Reader, metadata map[string]string, sha256sum string) (objInfo ObjectInfo, retErr error) {

var err error

// Validate if bucket name is valid and exists.

if _, err = fs.statBucketDir(bucket); err != nil {

return ObjectInfo{}, toObjectErr(err, bucket)

}

// This is a special case with size as '0' and object ends

// with a slash separator, we treat it like a valid operation

// and return success.

if isObjectDir(object, size) {

// Check if an object is present as one of the parent dir.

if fs.parentDirIsObject(bucket, path.Dir(object)) {

return ObjectInfo{}, toObjectErr(traceError(errFileAccessDenied), bucket, object)

}

return dirObjectInfo(bucket, object, size, metadata), nil

}

if err = checkPutObjectArgs(bucket, object, fs); err != nil {

return ObjectInfo{}, err

}

// Check if an object is present as one of the parent dir.

if fs.parentDirIsObject(bucket, path.Dir(object)) {

return ObjectInfo{}, toObjectErr(traceError(errFileAccessDenied), bucket, object)

}

// No metadata is set, allocate a new one.

if metadata == nil {

metadata = make(map[string]string)

}

fsMeta := newFSMetaV1()

fsMeta.Meta = metadata

var wlk *lock.LockedFile

if bucket != minioMetaBucket {

bucketMetaDir := pathJoin(fs.fsPath, minioMetaBucket, bucketMetaPrefix)

fsMetaPath := pathJoin(bucketMetaDir, bucket, object, fsMetaJSONFile)

wlk, err = fs.rwPool.Create(fsMetaPath)

if err != nil {

return ObjectInfo{}, toObjectErr(traceError(err), bucket, object)

}

// This close will allow for locks to be synchronized on `fs.json`.

defer wlk.Close()

defer func() {

// Remove meta file when PutObject encounters any error

if retErr != nil {

tmpDir := pathJoin(fs.fsPath, minioMetaTmpBucket, fs.fsUUID)

fsRemoveMeta(bucketMetaDir, fsMetaPath, tmpDir)

}

}()

}

// Uploaded object will first be written to the temporary location which will eventually

// be renamed to the actual location. It is first written to the temporary location

// so that cleaning it up will be easy if the server goes down.

tempObj := mustGetUUID()

// Initialize md5 writer.

md5Writer := md5.New()

hashWriters := []io.Writer{md5Writer}

var sha256Writer hash.Hash

if sha256sum != "" {

sha256Writer = sha256.New()

hashWriters = append(hashWriters, sha256Writer)

}

multiWriter := io.MultiWriter(hashWriters...)

// Limit the reader to its provided size if specified.

var limitDataReader io.Reader

if size > 0 {

// This is done so that we can avoid erroneous clients sending more data than the set content size.

limitDataReader = io.LimitReader(data, size)

} else {

// else we read till EOF.

limitDataReader = data

}

// Allocate a buffer to Read() from request body

bufSize := int64(readSizeV1)

if size > 0 && bufSize > size {

bufSize = size

}

buf := make([]byte, int(bufSize))

teeReader := io.TeeReader(limitDataReader, multiWriter)

fsTmpObjPath := pathJoin(fs.fsPath, minioMetaTmpBucket, fs.fsUUID, tempObj)

bytesWritten, err := fsCreateFile(fsTmpObjPath, teeReader, buf, size)

if err != nil {

fsRemoveFile(fsTmpObjPath)

errorIf(err, "Failed to create object %s/%s", bucket, object)

return ObjectInfo{}, toObjectErr(err, bucket, object)

}

// Should return IncompleteBody{} error when reader has fewer

// bytes than specified in request header.

if bytesWritten < size {

fsRemoveFile(fsTmpObjPath)

return ObjectInfo{}, traceError(IncompleteBody{})

}

// Delete the temporary object in the case of a

// failure. If PutObject succeeds, then there would be

// nothing to delete.

defer fsRemoveFile(fsTmpObjPath)

newMD5Hex := hex.EncodeToString(md5Writer.Sum(nil))

// Update the md5sum if not set with the newly calculated one.

if len(metadata["etag"]) == 0 {

metadata["etag"] = newMD5Hex

}

// md5Hex representation.

md5Hex := metadata["etag"]

if md5Hex != "" {

if newMD5Hex != md5Hex {

// Returns md5 mismatch.

return ObjectInfo{}, traceError(BadDigest{md5Hex, newMD5Hex})

}

}

if sha256sum != "" {

newSHA256sum := hex.EncodeToString(sha256Writer.Sum(nil))

if newSHA256sum != sha256sum {

return ObjectInfo{}, traceError(SHA256Mismatch{})

}

}

// Entire object was written to the temp location, now it's safe to rename it to the actual location.

fsNSObjPath := pathJoin(fs.fsPath, bucket, object)

if err = fsRenameFile(fsTmpObjPath, fsNSObjPath); err != nil {

return ObjectInfo{}, toObjectErr(err, bucket, object)

}

if bucket != minioMetaBucket {

// Write FS metadata after a successful namespace operation.

if _, err = fsMeta.WriteTo(wlk); err != nil {

return ObjectInfo{}, toObjectErr(err, bucket, object)

}

}

// Stat the file to fetch timestamp, size.

fi, err := fsStatFile(pathJoin(fs.fsPath, bucket, object))

if err != nil {

return ObjectInfo{}, toObjectErr(err, bucket, object)

}

// Success.

return fsMeta.ToObjectInfo(bucket, object, fi), nil

}

// DeleteObject - deletes an object from a bucket, this operation is destructive

// and there are no rollbacks supported.

func (fs fsObjects) DeleteObject(bucket, object string) error {

if err := checkDelObjArgs(bucket, object); err != nil {

return err

}

if _, err := fs.statBucketDir(bucket); err != nil {

return toObjectErr(err, bucket)

}

minioMetaBucketDir := pathJoin(fs.fsPath, minioMetaBucket)

fsMetaPath := pathJoin(minioMetaBucketDir, bucketMetaPrefix, bucket, object, fsMetaJSONFile)

if bucket != minioMetaBucket {

rwlk, lerr := fs.rwPool.Write(fsMetaPath)

if lerr == nil {

// This close will allow for fs locks to be synchronized on `fs.json`.

defer rwlk.Close()

}

if lerr != nil && lerr != errFileNotFound {

return toObjectErr(traceError(lerr), bucket, object)

}

}

// Delete the object.

if err := fsDeleteFile(pathJoin(fs.fsPath, bucket), pathJoin(fs.fsPath, bucket, object)); err != nil {

return toObjectErr(err, bucket, object)

}

if bucket != minioMetaBucket {

// Delete the metadata object.

err := fsDeleteFile(minioMetaBucketDir, fsMetaPath)

if err != nil && errorCause(err) != errFileNotFound {

return toObjectErr(err, bucket, object)

}

}

return nil

}

// list of all errors that can be ignored in tree walk operation in FS

var fsTreeWalkIgnoredErrs = append(baseIgnoredErrs, []error{

errFileNotFound,

errVolumeNotFound,

}...)

// Returns function "listDir" of the type listDirFunc.

// isLeaf - is used by listDir function to check if an entry

// is a leaf or non-leaf entry.

func (fs fsObjects) listDirFactory(isLeaf isLeafFunc) listDirFunc {

// listDir - lists all the entries at a given prefix and given entry in the prefix.

listDir := func(bucket, prefixDir, prefixEntry string) (entries []string, delayIsLeaf bool, err error) {

entries, err = readDir(pathJoin(fs.fsPath, bucket, prefixDir))

if err != nil {

return nil, false, err

}

entries, delayIsLeaf = filterListEntries(bucket, prefixDir, entries, prefixEntry, isLeaf)

return entries, delayIsLeaf, nil

}

// Return list factory instance.

return listDir

}

// getObjectETag is a helper function, which returns only the md5sum

// of the file on the disk.

func (fs fsObjects) getObjectETag(bucket, entry string) (string, error) {

fsMetaPath := pathJoin(fs.fsPath, minioMetaBucket, bucketMetaPrefix, bucket, entry, fsMetaJSONFile)

// Read `fs.json` to perhaps contend with

// parallel Put() operations.

rlk, err := fs.rwPool.Open(fsMetaPath)

// Ignore if `fs.json` is not available, this is true for pre-existing data.

if err != nil && err != errFileNotFound {

return "", toObjectErr(traceError(err), bucket, entry)

}

// If file is not found, we don't need to proceed forward.

if err == errFileNotFound {

return "", nil

}

// Read from fs metadata only if it exists.

defer fs.rwPool.Close(fsMetaPath)

fsMetaBuf, err := ioutil.ReadAll(rlk.LockedFile)

if err != nil {

// `fs.json` can be empty due to previously failed

// PutObject() transaction, if we arrive at such

// a situation we just ignore and continue.

if errorCause(err) != io.EOF {

return "", toObjectErr(err, bucket, entry)

}

}

// Check if FS metadata is valid, if not return error.

if !isFSMetaValid(parseFSVersion(fsMetaBuf), parseFSFormat(fsMetaBuf)) {

return "", toObjectErr(traceError(errCorruptedFormat), bucket, entry)

}

return extractETag(parseFSMetaMap(fsMetaBuf)), nil

}

// ListObjects - list all objects at prefix upto maxKeys., optionally delimited by '/'. Maintains the list pool

// state for future re-entrant list requests.

func (fs fsObjects) ListObjects(bucket, prefix, marker, delimiter string, maxKeys int) (loi ListObjectsInfo, e error) {

if err := checkListObjsArgs(bucket, prefix, marker, delimiter, fs); err != nil {

return loi, err

}

if _, err := fs.statBucketDir(bucket); err != nil {

return loi, err

}

// With max keys of zero we have reached eof, return right here.

if maxKeys == 0 {

return loi, nil

}

// For delimiter and prefix as '/' we do not list anything at all

// since according to s3 spec we stop at the 'delimiter'

// along // with the prefix. On a flat namespace with 'prefix'

// as '/' we don't have any entries, since all the keys are

// of form 'keyName/...'

if delimiter == slashSeparator && prefix == slashSeparator {

return loi, nil

}

// Over flowing count - reset to maxObjectList.

if maxKeys < 0 || maxKeys > maxObjectList {

maxKeys = maxObjectList

}

// Default is recursive, if delimiter is set then list non recursive.

recursive := true

if delimiter == slashSeparator {

recursive = false

}

// Convert entry to ObjectInfo

entryToObjectInfo := func(entry string) (objInfo ObjectInfo, err error) {

if hasSuffix(entry, slashSeparator) {

// Object name needs to be full path.

objInfo.Name = entry

objInfo.IsDir = true

return

}

// Protect reading `fs.json`.

objectLock := globalNSMutex.NewNSLock(bucket, entry)

objectLock.RLock()

var etag string

etag, err = fs.getObjectETag(bucket, entry)

objectLock.RUnlock()

if err != nil {

return ObjectInfo{}, err

}

// Stat the file to get file size.

var fi os.FileInfo

fi, err = fsStatFile(pathJoin(fs.fsPath, bucket, entry))

if err != nil {

return ObjectInfo{}, toObjectErr(err, bucket, entry)

}

// Success.

return ObjectInfo{

Name: entry,

Bucket: bucket,

Size: fi.Size(),

ModTime: fi.ModTime(),

IsDir: fi.IsDir(),

ETag: etag,

}, nil

}

heal := false // true only for xl.ListObjectsHeal()

walkResultCh, endWalkCh := fs.listPool.Release(listParams{bucket, recursive, marker, prefix, heal})

if walkResultCh == nil {

endWalkCh = make(chan struct{})

isLeaf := func(bucket, object string) bool {

// bucket argument is unused as we don't need to StatFile

// to figure if it's a file, just need to check that the

// object string does not end with "/".

return !hasSuffix(object, slashSeparator)

}

listDir := fs.listDirFactory(isLeaf)

walkResultCh = startTreeWalk(bucket, prefix, marker, recursive, listDir, isLeaf, endWalkCh)

}

var objInfos []ObjectInfo

var eof bool

var nextMarker string

// List until maxKeys requested.

for i := 0; i < maxKeys; {

walkResult, ok := <-walkResultCh

if !ok {

// Closed channel.

eof = true

break

}

// For any walk error return right away.

if walkResult.err != nil {

// File not found is a valid case.

if errorCause(walkResult.err) == errFileNotFound {

return loi, nil

}

return loi, toObjectErr(walkResult.err, bucket, prefix)

}

objInfo, err := entryToObjectInfo(walkResult.entry)

if err != nil {

return loi, nil

}

nextMarker = objInfo.Name

objInfos = append(objInfos, objInfo)

if walkResult.end {

eof = true

break

}

i++

}

// Save list routine for the next marker if we haven't reached EOF.

params := listParams{bucket, recursive, nextMarker, prefix, heal}

if !eof {

fs.listPool.Set(params, walkResultCh, endWalkCh)

}

result := ListObjectsInfo{IsTruncated: !eof}

for _, objInfo := range objInfos {

result.NextMarker = objInfo.Name

if objInfo.IsDir {

result.Prefixes = append(result.Prefixes, objInfo.Name)

continue

}

result.Objects = append(result.Objects, objInfo)

}

// Success.

return result, nil

}

// HealObject - no-op for fs. Valid only for XL.

func (fs fsObjects) HealObject(bucket, object string) (int, int, error) {

return 0, 0, traceError(NotImplemented{})

}

// HealBucket - no-op for fs, Valid only for XL.

func (fs fsObjects) HealBucket(bucket string) error {

return traceError(NotImplemented{})

}

// ListObjectsHeal - list all objects to be healed. Valid only for XL

func (fs fsObjects) ListObjectsHeal(bucket, prefix, marker, delimiter string, maxKeys int) (loi ListObjectsInfo, e error) {

return loi, traceError(NotImplemented{})

}

// ListBucketsHeal - list all buckets to be healed. Valid only for XL

func (fs fsObjects) ListBucketsHeal() ([]BucketInfo, error) {

return []BucketInfo{}, traceError(NotImplemented{})

}

func (fs fsObjects) ListUploadsHeal(bucket, prefix, marker, uploadIDMarker,

delimiter string, maxUploads int) (lmi ListMultipartsInfo, e error) {

return lmi, traceError(NotImplemented{})

}