cachefiles: narrow the scope of flushed requests when releasing fd

When an anonymous fd is released, only flush the requests
associated with it, rather than all of requests in xarray.

Fixes: 9032b6e8589f ("cachefiles: implement on-demand read")
Signed-off-by: Jia Zhu <[e-mail]>
Signed-off-by: David Howells <[e-mail]>
Reviewed-by: Jeffle Xu <[e-mail]>
Reviewed-by: Gao Xiang <[e-mail]>
Link: https://listman.redhat.com/archives/linux-cachefs/2022-June/006937.html

fs/cachefiles/ondemand.c

···
 	 * anon_fd.
 	 */
 	xas_for_each(&xas, req, ULONG_MAX) {
-		if (req->msg.opcode == CACHEFILES_OP_READ) {
+		if (req->msg.object_id == object_id &&
+		    req->msg.opcode == CACHEFILES_OP_READ) {
 			req->error = -EIO;
 			complete(&req->done);
 			xas_store(&xas, NULL);