return nil, err
		}

		// if object doesn't exist return error for If-Match conditional requests
		// If-None-Match should be allowed to proceed for non-existent objects
		if err != nil && opts.HasIfMatch && (isErrObjectNotFound(err) || isErrVersionNotFound(err)) {
			return nil, err
		}
	}

	userDefined := cloneMSS(opts.UserDefined)
	if opts.PreserveETag != "" {
		userDefined["etag"] = opts.PreserveETag

	opts, err := putOptsFromReq(ctx, r, bucket, object, metadata)
	if err != nil {
		writeErrorResponse(ctx, w, toAPIError(ctx, err), r.URL)
		return
	}

	if r.Header.Get(xhttp.IfMatch) != "" {
		opts.HasIfMatch = true
	}
	if opts.PreserveETag != "" ||
		r.Header.Get(xhttp.IfMatch) != "" ||
		r.Header.Get(xhttp.IfNoneMatch) != "" {
		opts.CheckPrecondFn = func(oi ObjectInfo) bool {

	PreserveETag                        string    // preserves this etag during a PUT call.
	NoLock                              bool      // indicates to lower layers if the caller is expecting to hold locks.
	HasIfMatch                          bool      // indicates if the request has If-Match header
	ProxyRequest                        bool      // only set for GET/HEAD in active-active replication scenario