minio/xl-v1.go
2016-04-29 01:29:09 -07:00

573 lines
16 KiB
Go

/*
* Minio Cloud Storage, (C) 2016 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 main
import (
"fmt"
"os"
slashpath "path"
"sort"
"strings"
"github.com/Sirupsen/logrus"
"github.com/klauspost/reedsolomon"
)
const (
// Part metadata file.
xlMetaV1File = "xl.json"
// Maximum erasure blocks.
maxErasureBlocks = 16
)
// XL layer structure.
type XL struct {
ReedSolomon reedsolomon.Encoder // Erasure encoder/decoder.
DataBlocks int
ParityBlocks int
storageDisks []StorageAPI
readQuorum int
writeQuorum int
}
// newXL instantiate a new XL.
func newXL(disks ...string) (StorageAPI, error) {
// Initialize XL.
xl := &XL{}
// Verify disks.
totalDisks := len(disks)
if totalDisks > maxErasureBlocks {
return nil, errMaxDisks
}
// isEven function to verify if a given number if even.
isEven := func(number int) bool {
return number%2 == 0
}
// TODO: verify if this makes sense in future.
if !isEven(totalDisks) {
return nil, errNumDisks
}
// Calculate data and parity blocks.
dataBlocks, parityBlocks := totalDisks/2, totalDisks/2
// Initialize reed solomon encoding.
rs, err := reedsolomon.New(dataBlocks, parityBlocks)
if err != nil {
return nil, err
}
// Save the reedsolomon.
xl.DataBlocks = dataBlocks
xl.ParityBlocks = parityBlocks
xl.ReedSolomon = rs
// Initialize all storage disks.
storageDisks := make([]StorageAPI, len(disks))
for index, disk := range disks {
var err error
storageDisks[index], err = newFS(disk)
if err != nil {
return nil, err
}
}
// Save all the initialized storage disks.
xl.storageDisks = storageDisks
// Figure out read and write quorum based on number of storage disks.
// Read quorum should be always N/2 + 1 (due to Vandermonde matrix
// erasure requirements)
xl.readQuorum = len(xl.storageDisks)/2 + 1
// Write quorum is assumed if we have total disks + 3
// parity. (Need to discuss this again)
xl.writeQuorum = len(xl.storageDisks)/2 + 3
if xl.writeQuorum > len(xl.storageDisks) {
xl.writeQuorum = len(xl.storageDisks)
}
// Return successfully initialized.
return xl, nil
}
// MakeVol - make a volume.
func (xl XL) MakeVol(volume string) error {
if !isValidVolname(volume) {
return errInvalidArgument
}
// Collect if all disks report volume exists.
var volumeExistsMap = make(map[int]struct{})
// Make a volume entry on all underlying storage disks.
for index, disk := range xl.storageDisks {
if err := disk.MakeVol(volume); err != nil {
log.WithFields(logrus.Fields{
"volume": volume,
}).Errorf("MakeVol failed with %s", err)
// We ignore error if errVolumeExists and creating a volume again.
if err == errVolumeExists {
volumeExistsMap[index] = struct{}{}
continue
}
return err
}
}
// Return err if all disks report volume exists.
if len(volumeExistsMap) == len(xl.storageDisks) {
return errVolumeExists
}
return nil
}
// DeleteVol - delete a volume.
func (xl XL) DeleteVol(volume string) error {
if !isValidVolname(volume) {
return errInvalidArgument
}
// Collect if all disks report volume not found.
var volumeNotFoundMap = make(map[int]struct{})
// Remove a volume entry on all underlying storage disks.
for index, disk := range xl.storageDisks {
if err := disk.DeleteVol(volume); err != nil {
log.WithFields(logrus.Fields{
"volume": volume,
}).Errorf("DeleteVol failed with %s", err)
// We ignore error if errVolumeNotFound.
if err == errVolumeNotFound {
volumeNotFoundMap[index] = struct{}{}
continue
}
return err
}
}
// Return err if all disks report volume not found.
if len(volumeNotFoundMap) == len(xl.storageDisks) {
return errVolumeNotFound
}
return nil
}
// ListVols - list volumes.
func (xl XL) ListVols() (volsInfo []VolInfo, err error) {
emptyCount := 0
// Success vols map carries successful results of ListVols from
// each disks.
var successVolsMap = make(map[int][]VolInfo)
for index, disk := range xl.storageDisks {
var vlsInfo []VolInfo
vlsInfo, err = disk.ListVols()
if err == nil {
if len(vlsInfo) == 0 {
emptyCount++
} else {
successVolsMap[index] = vlsInfo
}
}
}
// If all list operations resulted in an empty count which is same
// as your total storage disks, then it is a valid case return
// success with empty vols.
if emptyCount == len(xl.storageDisks) {
return []VolInfo{}, nil
} else if len(successVolsMap) < xl.readQuorum {
// If there is data and not empty, then we attempt quorum verification.
// Verify if we have enough quorum to list vols.
return nil, errReadQuorum
}
// Loop through success vols map and return the first value.
for index := range xl.storageDisks {
if _, ok := successVolsMap[index]; ok {
volsInfo = successVolsMap[index]
break
}
}
return volsInfo, nil
}
// StatVol - get volume stat info.
func (xl XL) StatVol(volume string) (volInfo VolInfo, err error) {
if !isValidVolname(volume) {
return VolInfo{}, errInvalidArgument
}
var statVols []VolInfo
volumeNotFoundErrCnt := 0
for _, disk := range xl.storageDisks {
volInfo, err = disk.StatVol(volume)
if err == nil {
// Collect all the successful attempts to verify quorum
// subsequently.
statVols = append(statVols, volInfo)
} else if err == errVolumeNotFound {
// Count total amount of volume not found errors.
volumeNotFoundErrCnt++
} else if err != nil {
log.WithFields(logrus.Fields{
"volume": volume,
}).Errorf("StatVol failed with %s", err)
return VolInfo{}, err
}
}
// If volume not found err count is same as total storage disks, we
// really don't have the bucket, report a valid error.
if volumeNotFoundErrCnt == len(xl.storageDisks) {
return VolInfo{}, errVolumeNotFound
} else if len(statVols) < xl.readQuorum {
// If one of the disks have bucket we need to validate if we
// have read quorum, if not fail.
return VolInfo{}, errReadQuorum
}
// If successful remove all the duplicates and keep the latest one.
volInfo = removeDuplicateVols(statVols)[0]
return volInfo, nil
}
// isLeafDirectory - check if a given path is leaf directory. i.e
// there are no more directories inside it. Erasure code backend
// format it means that the parent directory is the actual object name.
func isLeafDirectory(disk StorageAPI, volume, leafPath string) (isLeaf bool) {
var markerPath string
var xlListCount = 1000 // Count page.
for {
fileInfos, eof, err := disk.ListFiles(volume, leafPath, markerPath, false, xlListCount)
if err != nil {
log.WithFields(logrus.Fields{
"volume": volume,
"leafPath": leafPath,
"markerPath": markerPath,
"recursive": false,
"count": xlListCount,
}).Errorf("ListFiles failed with %s", err)
break
}
for _, fileInfo := range fileInfos {
if fileInfo.Mode.IsDir() {
// Directory found, not a leaf directory, return right here.
return false
}
}
if eof {
break
}
// MarkerPath to get the next set of files.
markerPath = fileInfos[len(fileInfos)-1].Name
}
// Exhausted all the entries, no directories found must be leaf
// return right here.
return true
}
// extractMetadata - extract xl metadata.
func extractMetadata(disk StorageAPI, volume, path string) (xlMetaV1, error) {
xlMetaV1FilePath := slashpath.Join(path, xlMetaV1File)
// We are not going to read partial data from metadata file,
// read the whole file always.
offset := int64(0)
metadataReader, err := disk.ReadFile(volume, xlMetaV1FilePath, offset)
if err != nil {
log.WithFields(logrus.Fields{
"volume": volume,
"path": xlMetaV1FilePath,
"offset": offset,
}).Errorf("ReadFile failed with %s", err)
return xlMetaV1{}, err
}
// Close metadata reader.
defer metadataReader.Close()
metadata, err := xlMetaV1Decode(metadataReader)
if err != nil {
log.WithFields(logrus.Fields{
"volume": volume,
"path": xlMetaV1FilePath,
"offset": offset,
}).Errorf("xlMetaV1Decode failed with %s", err)
return xlMetaV1{}, err
}
return metadata, nil
}
// Extract file info from paths.
func extractFileInfo(disk StorageAPI, volume, path string) (FileInfo, error) {
fileInfo := FileInfo{}
fileInfo.Volume = volume
fileInfo.Name = path
metadata, err := extractMetadata(disk, volume, path)
if err != nil {
log.WithFields(logrus.Fields{
"volume": volume,
"path": path,
}).Errorf("extractMetadata failed with %s", err)
return FileInfo{}, err
}
fileInfo.Size = metadata.Stat.Size
fileInfo.ModTime = metadata.Stat.ModTime
fileInfo.Mode = os.FileMode(0644) // This is a file already.
return fileInfo, nil
}
// byFileInfoName is a collection satisfying sort.Interface.
type byFileInfoName []FileInfo
func (d byFileInfoName) Len() int { return len(d) }
func (d byFileInfoName) Swap(i, j int) { d[i], d[j] = d[j], d[i] }
func (d byFileInfoName) Less(i, j int) bool { return d[i].Name < d[j].Name }
// ListFiles files at prefix.
func (xl XL) ListFiles(volume, prefix, marker string, recursive bool, count int) (filesInfo []FileInfo, eof bool, err error) {
if !isValidVolname(volume) {
return nil, true, errInvalidArgument
}
// TODO: Fix: If readQuorum is met, its assumed that disks are in consistent file list.
// exclude disks those are not in consistent file list and check count of remaining disks
// are met readQuorum.
// Treat empty file list specially
emptyCount := 0
errCount := 0
successCount := 0
var firstFilesInfo []FileInfo
var firstEOF bool
var firstErr error
for _, disk := range xl.storageDisks {
if filesInfo, eof, err = listFiles(disk, volume, prefix, marker, recursive, count); err == nil {
// we need to return first successful result
if firstFilesInfo == nil {
firstFilesInfo = filesInfo
firstEOF = eof
}
if len(filesInfo) == 0 {
emptyCount++
} else {
successCount++
}
} else {
if firstErr == nil {
firstErr = err
}
errCount++
}
}
if errCount >= xl.readQuorum {
return nil, false, firstErr
} else if successCount >= xl.readQuorum {
return firstFilesInfo, firstEOF, nil
} else if emptyCount >= xl.readQuorum {
return []FileInfo{}, true, nil
}
return nil, false, errReadQuorum
}
func listFiles(disk StorageAPI, volume, prefix, marker string, recursive bool, count int) (filesInfo []FileInfo, eof bool, err error) {
var fsFilesInfo []FileInfo
var markerPath = marker
if marker != "" {
isLeaf := isLeafDirectory(disk, volume, retainSlash(marker))
if isLeaf {
// For leaf for now we just point to the first block, make it
// dynamic in future based on the availability of storage disks.
markerPath = slashpath.Join(marker, xlMetaV1File)
}
}
// Loop and capture the proper fileInfos, requires extraction and
// separation of XL related metadata information.
for {
fsFilesInfo, eof, err = disk.ListFiles(volume, prefix, markerPath, recursive, count)
if err != nil {
log.WithFields(logrus.Fields{
"volume": volume,
"prefix": prefix,
"marker": markerPath,
"recursive": recursive,
"count": count,
}).Errorf("ListFiles failed with %s", err)
return nil, true, err
}
for _, fsFileInfo := range fsFilesInfo {
// Skip metadata files.
if strings.HasSuffix(fsFileInfo.Name, xlMetaV1File) {
continue
}
var fileInfo FileInfo
var isLeaf bool
if fsFileInfo.Mode.IsDir() {
isLeaf = isLeafDirectory(disk, volume, fsFileInfo.Name)
}
if isLeaf || !fsFileInfo.Mode.IsDir() {
// Extract the parent of leaf directory or file to get the
// actual name.
path := slashpath.Dir(fsFileInfo.Name)
fileInfo, err = extractFileInfo(disk, volume, path)
if err != nil {
log.WithFields(logrus.Fields{
"volume": volume,
"path": path,
}).Errorf("extractFileInfo failed with %s", err)
// For a leaf directory, if err is FileNotFound then
// perhaps has a missing metadata. Ignore it and let
// healing finish its job it will become available soon.
if err == errFileNotFound {
continue
}
// For any other errors return to the caller.
return nil, true, err
}
} else {
fileInfo = fsFileInfo
}
filesInfo = append(filesInfo, fileInfo)
count--
if count == 0 {
break
}
}
if len(fsFilesInfo) > 0 {
// markerPath for the next disk.ListFiles() iteration.
markerPath = fsFilesInfo[len(fsFilesInfo)-1].Name
}
if count == 0 && recursive && !strings.HasSuffix(markerPath, xlMetaV1File) {
// If last entry is not xl.json then loop once more to check if we have reached eof.
fsFilesInfo, eof, err = disk.ListFiles(volume, prefix, markerPath, recursive, 1)
if err != nil {
log.WithFields(logrus.Fields{
"volume": volume,
"prefix": prefix,
"marker": markerPath,
"recursive": recursive,
"count": 1,
}).Errorf("ListFiles failed with %s", err)
return nil, true, err
}
if !eof {
// file.N and xl.json are always in pairs and hence this
// entry has to be xl.json. If not better to manually investigate
// and fix it.
// For the next ListFiles() call we can safely assume that the
// marker is "object/xl.json"
if !strings.HasSuffix(fsFilesInfo[0].Name, xlMetaV1File) {
log.WithFields(logrus.Fields{
"volume": volume,
"prefix": prefix,
"fsFileInfo.Name": fsFilesInfo[0].Name,
}).Errorf("ListFiles failed with %s, expected %s to be a xl.json file.", err, fsFilesInfo[0].Name)
return nil, true, errUnexpected
}
}
}
if count == 0 || eof {
break
}
}
// Sort to make sure we sort entries back properly.
sort.Sort(byFileInfoName(filesInfo))
return filesInfo, eof, nil
}
// Object API.
// StatFile - stat a file
func (xl XL) StatFile(volume, path string) (FileInfo, error) {
if !isValidVolname(volume) {
return FileInfo{}, errInvalidArgument
}
if !isValidPath(path) {
return FileInfo{}, errInvalidArgument
}
// Acquire read lock.
nsMutex.RLock(volume, path)
_, metadata, heal, err := xl.listOnlineDisks(volume, path)
nsMutex.RUnlock(volume, path)
if err != nil {
log.WithFields(logrus.Fields{
"volume": volume,
"path": path,
}).Errorf("listOnlineDisks failed with %s", err)
return FileInfo{}, err
}
if heal {
// Heal in background safely, since we already have read quorum disks.
go func() {
if err = xl.healFile(volume, path); err != nil {
log.WithFields(logrus.Fields{
"volume": volume,
"path": path,
}).Errorf("healFile failed with %s", err)
return
}
}()
}
// Return file info.
return FileInfo{
Volume: volume,
Name: path,
Size: metadata.Stat.Size,
ModTime: metadata.Stat.ModTime,
Mode: os.FileMode(0644),
}, nil
}
// DeleteFile - delete a file
func (xl XL) DeleteFile(volume, path string) error {
if !isValidVolname(volume) {
return errInvalidArgument
}
if !isValidPath(path) {
return errInvalidArgument
}
// Loop through and delete each chunks.
for index, disk := range xl.storageDisks {
erasureFilePart := slashpath.Join(path, fmt.Sprintf("file.%d", index))
err := disk.DeleteFile(volume, erasureFilePart)
if err != nil {
log.WithFields(logrus.Fields{
"volume": volume,
"path": path,
}).Errorf("DeleteFile failed with %s", err)
return err
}
xlMetaV1FilePath := slashpath.Join(path, xlMetaV1File)
err = disk.DeleteFile(volume, xlMetaV1FilePath)
if err != nil {
log.WithFields(logrus.Fields{
"volume": volume,
"path": path,
}).Errorf("DeleteFile failed with %s", err)
return err
}
}
return nil
}