Fix reading uninitialized variable in receive_read

When zfs_file_read returns error, resid may be uninitialized.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Richard Yao <richard.yao@alumni.stonybrook.edu>
Signed-off-by: Chunwei Chen <david.chen@nutanix.com>
Closes #14404

module/zfs/dmu_recv.c

@@ -1500,11 +1500,11 @@ receive_read(dmu_recv_cookie_t *drc, int len, void *buf)
 	    (drc->drc_featureflags & DMU_BACKUP_FEATURE_RAW) != 0);
 
 	while (done < len) {
-		ssize_t resid;
+		ssize_t resid = len - done;
 		zfs_file_t *fp = drc->drc_fp;
 		int err = zfs_file_read(fp, (char *)buf + done,
 		    len - done, &resid);
-		if (resid == len - done) {
+		if (err == 0 && resid == len - done) {
 			/*
 			 * Note: ECKSUM or ZFS_ERR_STREAM_TRUNCATED indicates
 			 * that the receive was interrupted and can