s3: Force a prefix removal using a special header (#12504)

An S3 client can send `x-minio-force-delete: true` to remove a prefix.

cmd/object-handlers.go

@@ -22,6 +22,7 @@ import (
 	"context"
 	"encoding/hex"
 	"encoding/xml"
+	"errors"
 	"fmt"
 	"io"
 	"net/http"
@@ -3270,6 +3271,10 @@ func (api objectAPIHandlers) DeleteObjectHandler(w http.ResponseWriter, r *http.
 
 	apiErr := ErrNone
 	if rcfg, _ := globalBucketObjectLockSys.Get(bucket); rcfg.LockEnabled {
+		if opts.DeletePrefix {
+			writeErrorResponse(ctx, w, toAPIError(ctx, errors.New("force-delete is forbidden in a locked-enabled bucket")), r.URL, guessIsBrowserReq(r))
+			return
+		}
 		if vID != "" {
 			apiErr = enforceRetentionBypassForDelete(ctx, r, bucket, ObjectToDelete{
 				ObjectName: object,