IPFS repo cannot be stored on a NAS (SMB, etc.).

#### Version information:

go-ipfs version: 0.8.0
Repo version: 11
System version: amd64/darwin
Golang version: go1.15.8

OSX Version: 10,14,8

#### Description:

As per title. IPFS worked fine with default setup [ie. storing data locally]. I then tried to move my repo to a NAS [mounted via SMB] by adding `export IPFS_PATH=/Volumes/stuzbot/IPFS` to my `~/.zshrc` file and re-initialising.

Now, when I run `ipfs daemon` I get the following error:

````
Initializing daemon...
go-ipfs version: 0.8.0
Repo version: 11
System version: amd64/darwin
Golang version: go1.15.8

Error: cannot acquire lock: Lock FcntlFlock of /Volumes/stuzbot/IPFS/repo.lock failed: operation not supported
````

I've tried both reinitialising the repo from scratch at the new NAS location with `ipfs init` and also copying over the existing contents from the old default `~/.ipfs` location. But I get the same error each time. I can see that, after running `ipfs daemon` a zero bytes `repo.lock` file is actually created in the repo directory but the error message still persists.

I have full read/write permissions for the NAS itself and for the directory I am trying to use as my IPFS repo.