`--nfs-cache-type symlink` is similar to `--nfs-cache-type disk` in
that it uses an on disk cache, but the cache entries are held as
symlinks. Rclone will use the handle of the underlying file as the NFS
handle which improves performance.
This problem was caused by the defaults not being set for the options
after the conversion to the new config system in
28ba4b832d serve nfs: convert options to new style
This makes the nfs serve options globally available so nfsmount can
use them directly.
Fixes#8029
This also
- move in use options (Opt) from vfsflags to vfscommon
- change os.FileMode to vfscommon.FileMode in parameters
- rework vfscommon.FileMode and add tests
Before this change, writing files to an `nfsmount` via Finder on macOS would
cause critical errors, rendering `nfsmount` effectively unusable on macOS. This
change fixes the issue so that writes via Finder should be possible.
The issue was primarily caused by the handler's HandleLimit being set to -1. -1 is
the correct default for a NullAuthHandler, but not for a CachingHandler, which
interprets -1 not as "no limit" but as "no cache".
This change sets a high default of 1000000, and gives the user control over it
with a new --nfs-cache-handle-limit flag (available in both `serve nfs` and
`nfsmount`. A minimum of 5 is enforced, as any lower than this will be
insufficient to support directory listing.
Summary:
Adding a new command to serve any remote over NFS. This is only useful for new macOS versions where FUSE mounts are not available.
* Added willscot/go-nfs dependency and updated go.mod and go.sum
Test Plan:
```
go run rclone.go serve nfs --http-url https://beta.rclone.org :http:
```
Test that it is serving correctly by mounting the NFS directory.
```
mkdir nfs-test
mount -oport=58654,mountport=58654 localhost: nfs-test
```
Then we can list the mounted directory to see it is working.
```
ls nfs-test
```
