fs: define SlowModTime and SlowHash features in the relevant backends

backend/local/local.go

@@ -231,6 +231,7 @@ func NewFs(name, root string, m configmap.Mapper) (fs.Fs, error) {
 		CaseInsensitive:         f.caseInsensitive(),
 		CanHaveEmptyDirectories: true,
 		IsLocal:                 true,
+		SlowHash:                true,
 	}).Fill(f)
 	if opt.FollowSymlinks {
 		f.lstat = os.Stat

backend/qingstor/qingstor.go

@@ -356,6 +356,7 @@ func NewFs(name, root string, m configmap.Mapper) (fs.Fs, error) {
 		WriteMimeType:     true,
 		BucketBased:       true,
 		BucketBasedRootOK: true,
+		SlowModTime:       true,
 	}).Fill(f)
 
 	if f.rootBucket != "" && f.rootDirectory != "" {

backend/s3/s3.go

@@ -1334,6 +1334,7 @@ func NewFs(name, root string, m configmap.Mapper) (fs.Fs, error) {
 		BucketBasedRootOK: true,
 		SetTier:           true,
 		GetTier:           true,
+		SlowModTime:       true,
 	}).Fill(f)
 	if f.rootBucket != "" && f.rootDirectory != "" {
 		// Check to see if the object exists

backend/sftp/sftp.go

@@ -500,6 +500,7 @@ func NewFsWithConnection(ctx context.Context, name string, root string, m config
 	}
 	f.features = (&fs.Features{
 		CanHaveEmptyDirectories: true,
+		SlowHash:                true,
 	}).Fill(f)
 	// Make a connection and pool it to return errors early
 	c, err := f.getSftpConnection()

backend/swift/swift.go

@@ -447,6 +447,7 @@ func NewFsWithConnection(opt *Options, name, root string, c *swift.Connection, n
 		WriteMimeType:     true,
 		BucketBased:       true,
 		BucketBasedRootOK: true,
+		SlowModTime:       true,
 	}).Fill(f)
 	if f.rootContainer != "" && f.rootDirectory != "" {
 		// Check to see if the object exists - ignoring directory markers

fs/fs.go

@@ -515,6 +515,8 @@ type Features struct {
 	GetTier                 bool // allows to retrieve storage tier of objects
 	ServerSideAcrossConfigs bool // can server side copy between different remotes of the same type
 	IsLocal                 bool // is the local backend
+	SlowModTime             bool // if calling ModTime() generally takes an extra transaction
+	SlowHash                bool // if calling Hash() generally takes an extra transaction
 
 	// Purge all files in the root and the root directory
 	//
@@ -792,6 +794,10 @@ func (ft *Features) Mask(f Fs) *Features {
 	ft.BucketBasedRootOK = ft.BucketBasedRootOK && mask.BucketBasedRootOK
 	ft.SetTier = ft.SetTier && mask.SetTier
 	ft.GetTier = ft.GetTier && mask.GetTier
+	ft.ServerSideAcrossConfigs = ft.ServerSideAcrossConfigs && mask.ServerSideAcrossConfigs
+	// ft.IsLocal = ft.IsLocal && mask.IsLocal Don't propagate IsLocal
+	ft.SlowModTime = ft.SlowModTime && mask.SlowModTime
+	ft.SlowHash = ft.SlowHash && mask.SlowHash
 
 	if mask.Purge == nil {
 		ft.Purge = nil