7121: Log all errors (except the everyday "not found") encountered during CompareAndT...

[arvados.git] / services / keepstore / volume.go

diff --git a/services/keepstore/volume.go b/services/keepstore/volume.go
index 1b5294952820b5cb2f0be2d53c37eb84f2cefed5..d17af446a6b2674f9e86330ace0fea457d023e2a 100644 (file)
--- a/services/keepstore/volume.go
+++ b/services/keepstore/volume.go
@@ -11,8 +11,17 @@ import (
 )
 
 type Volume interface {
+       // Get a block. IFF the returned error is nil, the caller must
+       // put the returned slice back into the buffer pool when it's
+       // finished with it.
        Get(loc string) ([]byte, error)
-       Put(loc string, block []byte) error
+       // Confirm Get() would return a buffer with exactly the same
+       // content as buf. If so, return nil. If not, return
+       // CollisionError or DiskHashError (depending on whether the
+       // data on disk matches the expected hash), or whatever error
+       // was encountered opening/reading the file.
+       Compare(loc string, data []byte) error
+       Put(loc string, data []byte) error
        Touch(loc string) error
        Mtime(loc string) (time.Time, error)
        IndexTo(prefix string, writer io.Writer) error