@ -224,76 +224,28 @@ func (xl xlObjects) readXLMetadata(bucket, object string) (xlMeta xlMetaV1, err
return xlMeta , nil
}
// renameXLMetadata - renames `xl.json` from source prefix to destination prefix .
func ( xl xlObjects ) r enameXLMetadata( srcBucket , srcPrefix , dstBucket , dstPrefix string ) error {
// Undo rename xl metadata, renames successfully renamed `xl.json` back to source location .
func ( xl xlObjects ) undoR enameXLMetadata( srcBucket , srcPrefix , dstBucket , dstPrefix string , errs [ ] error ) {
var wg = & sync . WaitGroup { }
var mErrs = make ( [ ] error , len ( xl . storageDisks ) )
srcJSONFile := path . Join ( srcPrefix , xlMetaJSONFile )
dstJSONFile := path . Join ( dstPrefix , xlMetaJSONFile )
// Rename `xl.json` to all disks in parallel.
// Undo rename `xl.json` on disks where RenameFile succeeded.
for index , disk := range xl . storageDisks {
if disk == nil {
mErrs [ index ] = errDiskNotFound
continue
}
// Undo rename object in parallel.
wg . Add ( 1 )
// Rename `xl.json` in a routine.
go func ( index int , disk StorageAPI ) {
defer wg . Done ( )
// Renames `xl.json` from source prefix to destination prefix.
rErr := disk . RenameFile ( srcBucket , srcJSONFile , dstBucket , dstJSONFile )
if rErr != nil {
mErrs [ index ] = rErr
if errs [ index ] != nil {
return
}
// Delete any dangling directories.
dErr := disk . DeleteFile ( srcBucket , srcPrefix )
if dErr != nil {
mErrs [ index ] = dErr
return
}
mErrs [ index ] = nil
_ = disk . RenameFile ( dstBucket , dstJSONFile , srcBucket , srcJSONFile )
} ( index , disk )
}
// Wait for all the routines.
wg . Wait ( )
// Gather err count.
var errCount = 0
for _ , err := range mErrs {
if err == nil {
continue
}
errCount ++
}
// We can safely allow RenameFile errors up to len(xl.storageDisks) - xl.writeQuorum
// otherwise return failure. Cleanup successful renames.
if errCount > len ( xl . storageDisks ) - xl . writeQuorum {
// Check we have successful read quorum.
if errCount <= len ( xl . storageDisks ) - xl . readQuorum {
return nil // Return success.
} // else - failed to acquire read quorum.
// Undo rename `xl.json` on disks where RenameFile succeeded.
for index , disk := range xl . storageDisks {
if disk == nil {
continue
}
// Undo rename object in parallel.
wg . Add ( 1 )
go func ( index int , disk StorageAPI ) {
defer wg . Done ( )
if mErrs [ index ] != nil {
return
}
_ = disk . RenameFile ( dstBucket , dstJSONFile , srcBucket , srcJSONFile )
} ( index , disk )
}
wg . Wait ( )
return errXLWriteQuorum
}
return nil
}
// deleteXLMetadata - deletes `xl.json` on a single disk.
@ -322,6 +274,27 @@ func writeXLMetadata(disk StorageAPI, bucket, prefix string, xlMeta xlMetaV1) er
return nil
}
// deleteAllXLMetadata - deletes all partially written `xl.json` depending on errs.
func ( xl xlObjects ) deleteAllXLMetadata ( bucket , prefix string , errs [ ] error ) {
var wg = & sync . WaitGroup { }
// Delete all the `xl.json` left over.
for index , disk := range xl . storageDisks {
if disk == nil {
continue
}
// Undo rename object in parallel.
wg . Add ( 1 )
go func ( index int , disk StorageAPI ) {
defer wg . Done ( )
if errs [ index ] != nil {
return
}
_ = deleteXLMetdata ( disk , bucket , prefix )
} ( index , disk )
}
wg . Wait ( )
}
// writeUniqueXLMetadata - writes unique `xl.json` content for each disk in order.
func ( xl xlObjects ) writeUniqueXLMetadata ( bucket , prefix string , xlMetas [ ] xlMetaV1 ) error {
var wg = & sync . WaitGroup { }
@ -352,38 +325,26 @@ func (xl xlObjects) writeUniqueXLMetadata(bucket, prefix string, xlMetas []xlMet
// Wait for all the routines.
wg . Wait ( )
var errCount = 0
// Return the first error.
for _ , err := range mErrs {
if err == nil {
continue
}
errCount ++
}
// Count all the errors and validate if we have write quorum.
if errCount > len ( xl . storageDisks ) - xl . writeQuorum {
// Validate if we have read quorum, then return success.
if errCount > len ( xl . storageDisks ) - xl . readQuorum {
// Do we have write quorum?.
if ! isQuorum ( mErrs , xl . writeQuorum ) {
// Validate if we have read quorum.
if isQuorum ( mErrs , xl . readQuorum ) {
// Return success.
return nil
}
// Delete all the `xl.json` left over.
for index , disk := range xl . storageDisks {
if disk == nil {
continue
}
// Undo rename object in parallel.
wg . Add ( 1 )
go func ( index int , disk StorageAPI ) {
defer wg . Done ( )
if mErrs [ index ] != nil {
return
}
_ = deleteXLMetdata ( disk , bucket , prefix )
} ( index , disk )
}
wg . Wait ( )
// Delete all `xl.json` successfully renamed.
xl . deleteAllXLMetadata ( bucket , prefix , mErrs )
return errXLWriteQuorum
}
// For all other errors return.
for _ , err := range mErrs {
if err != nil && err != errDiskNotFound {
return err
}
}
// Success.
return nil
}
@ -417,37 +378,25 @@ func (xl xlObjects) writeSameXLMetadata(bucket, prefix string, xlMeta xlMetaV1)
// Wait for all the routines.
wg . Wait ( )
var errCount = 0
// Return the first error.
for _ , err := range mErrs {
if err == nil {
continue
}
errCount ++
}
// Count all the errors and validate if we have write quorum.
if errCount > len ( xl . storageDisks ) - xl . writeQuorum {
// Validate if we have read quorum, then return success.
if errCount > len ( xl . storageDisks ) - xl . readQuorum {
// Do we have write Quorum?.
if ! isQuorum ( mErrs , xl . writeQuorum ) {
// Do we have readQuorum?.
if isQuorum ( mErrs , xl . readQuorum ) {
// Return success.
return nil
}
// Delete all the `xl.json` left over.
for index , disk := range xl . storageDisks {
if disk == nil {
continue
}
// Undo rename object in parallel.
wg . Add ( 1 )
go func ( index int , disk StorageAPI ) {
defer wg . Done ( )
if mErrs [ index ] != nil {
return
}
_ = deleteXLMetdata ( disk , bucket , prefix )
} ( index , disk )
}
wg . Wait ( )
// Delete all `xl.json` successfully renamed.
xl . deleteAllXLMetadata ( bucket , prefix , mErrs )
return errXLWriteQuorum
}
// For any other errors delete `xl.json` as well.
for _ , err := range mErrs {
if err != nil && err != errDiskNotFound {
return err
}
}
// Success.
return nil
}
Harshavardhana
8 years ago
committed by