accessPolicy: Implement Put, Get, Delete access policy.

This patch implements Get,Put,Delete bucket policies

Supporting - http://docs.aws.amazon.com/AmazonS3/latest/dev/access-policy-language-overview.html

Currently supports following actions.

   "*":                             true,
   "s3:*":                          true,
   "s3:GetObject":                  true,
   "s3:ListBucket":                 true,
   "s3:PutObject":                  true,
   "s3:CreateBucket":               true,
   "s3:GetBucketLocation":          true,
   "s3:DeleteBucket":               true,
   "s3:DeleteObject":               true,
   "s3:AbortMultipartUpload":       true,
   "s3:ListBucketMultipartUploads": true,
   "s3:ListMultipartUploadParts":   true,

following conditions for "StringEquals" and "StringNotEquals"

   "s3:prefix", "s3:max-keys"

pkg/fs/fs.go

@@ -31,17 +31,10 @@ type Filesystem struct {
 	minFreeDisk      int64
 	rwLock           *sync.RWMutex
 	multiparts       *Multiparts
-	buckets          *Buckets
 	listServiceReqCh chan<- listServiceReq
 	timeoutReqCh     chan<- uint32
 }
 
-// Buckets holds acl information
-type Buckets struct {
-	Version  string `json:"version"`
-	Metadata map[string]*BucketMetadata
-}
-
 // MultipartSession holds active session information
 type MultipartSession struct {
 	TotalParts int
@@ -59,7 +52,6 @@ type Multiparts struct {
 
 // New instantiate a new donut
 func New(rootPath string, minFreeDisk int64) (Filesystem, *probe.Error) {
-	setFSBucketsMetadataPath(filepath.Join(rootPath, "$buckets.json"))
 	setFSMultipartsMetadataPath(filepath.Join(rootPath, "$multiparts-session.json"))
 
 	var err *probe.Error
@@ -80,27 +72,12 @@ func New(rootPath string, minFreeDisk int64) (Filesystem, *probe.Error) {
 		}
 	}
 
-	var buckets *Buckets
-	buckets, err = loadBucketsMetadata()
-	if err != nil {
-		if os.IsNotExist(err.ToGoError()) {
-			buckets = &Buckets{
-				Version:  "1",
-				Metadata: make(map[string]*BucketMetadata),
-			}
-			if err = saveBucketsMetadata(*buckets); err != nil {
-				return Filesystem{}, err.Trace()
-			}
-		} else {
-			return Filesystem{}, err.Trace()
-		}
-	}
 	fs := Filesystem{
 		rwLock: &sync.RWMutex{},
 	}
 	fs.path = rootPath
 	fs.multiparts = multiparts
-	fs.buckets = buckets
+
 	/// Defaults
 
 	// minium free disk required for i/o operations to succeed.