fh_update dropbox errors on ReadyNAS NV+

mazerj wrote:

StephenB - There are definitely .dropbox dirs/files on the nfs shares -- these are generated by the client machines when users run the linux dropbox client, which is common. The NV+ is serving up linux home directories for my lab. This would mean that fh_update in nfsd is generating a kernel error message, but exclusively when reading|writing these dropbox files. Sort of makes sense as to where the error messages are coming from and confirms it's not some sort of rogue dropbox server running on my raid, although doesn't explain why fh_update has problems with stuff in the .dropbox directories. I'll poke around a bit more and see if I can figure out exactly what fh_update is doing. These are not the actual dropbox data dirs, but rather the internal state info..

There is a perfectly valid situation where fh_update gets called on an already uptodate filehandle - in nfsd_create_v3 where a CREATE_UNCHECKED finds an existing file and wants to just set the size. We could possible optimise out the call in that case, but the only harm involved is that fh_update prints a warning, so it is easier to remove the warning.