fix: allow CopyObject/PutObjecTags on pre-existing content (#10485)

fixes #10475

cmd/fs-v1-metadata.go

@@ -225,7 +225,6 @@ func (m *fsMetaV1) ReadFrom(ctx context.Context, lk *lock.LockedFile) (n int64,
 	}
 
 	if len(fsMetaBuf) == 0 {
-		logger.LogIf(ctx, io.EOF)
 		return 0, io.EOF
 	}
 

cmd/fs-v1.go

@@ -19,6 +19,7 @@ package cmd
 import (
 	"bytes"
 	"context"
+	"errors"
 	"fmt"
 	"io"
 	"io/ioutil"
@@ -622,9 +623,16 @@ func (fs *FSObjects) CopyObject(ctx context.Context, srcBucket, srcObject, dstBu
 		fsMetaPath := pathJoin(fs.fsPath, minioMetaBucket, bucketMetaPrefix, srcBucket, srcObject, fs.metaJSONFile)
 		wlk, err := fs.rwPool.Write(fsMetaPath)
 		if err != nil {
+			if !errors.Is(err, errFileNotFound) {
 				logger.LogIf(ctx, err)
 				return oi, toObjectErr(err, srcBucket, srcObject)
 			}
+			wlk, err = fs.rwPool.Create(fsMetaPath)
+			if err != nil {
+				logger.LogIf(ctx, err)
+				return oi, toObjectErr(err, srcBucket, srcObject)
+			}
+		}
 		// This close will allow for locks to be synchronized on `fs.json`.
 		defer wlk.Close()
 
@@ -1491,9 +1499,16 @@ func (fs *FSObjects) PutObjectTags(ctx context.Context, bucket, object string, t
 	fsMeta := fsMetaV1{}
 	wlk, err := fs.rwPool.Write(fsMetaPath)
 	if err != nil {
+		if !errors.Is(err, errFileNotFound) {
 			logger.LogIf(ctx, err)
 			return toObjectErr(err, bucket, object)
 		}
+		wlk, err = fs.rwPool.Create(fsMetaPath)
+		if err != nil {
+			logger.LogIf(ctx, err)
+			return toObjectErr(err, bucket, object)
+		}
+	}
 	// This close will allow for locks to be synchronized on `fs.json`.
 	defer wlk.Close()