Updated the contents of struct fs.file.
Updated the contents of struct fs.file.

BanzaiMan/gcsfuse,GoogleCloudPlatform/gcsfuse,kahing/gcsfuse,GoogleCloudPlatform/gcsfuse,jacobsa/timeutil,BanzaiMan/gcsfuse,jacobsa/ratelimit,mbrukman/gcsfuse,GoogleCloudPlatform/gcsfuse