Hold dataMu for writing in CachingInodeOperations.WriteOut.
Hold dataMu for writing in CachingInodeOperations.WriteOut.

fsutil.SyncDirtyAll mutates the DirtySet.

PiperOrigin-RevId: 236183349
Change-Id: I7e809d5b406ac843407e61eff17d81259a819b4f

google/gvisor,google/gvisor,google/gvisor,google/gvisor,google/gvisor,google/gvisor,google/gvisor,google/gvisor