sshfs: rejects some options
 

I got passwordless sshfs mounting working OK ...
... and then set about optimising it but sshfs rejected some options.

The sshfs documentation (man page and --help output, slightly different), groups command line options by the subsystems it uses:

• iconv
• module (kernel module?)
• fuse
• mount
• ssh
• sshfs (itself)

There are a lot of options so I listed the ones I wanted to try by subsystem ...

• iconv None required
• module
  -o rellinks
• fuse
  -o intr
  -o no_remote_lock
• mount
  -o noatime,nodiratime,noiversion
• ssh None required (all set in ~/.ssh/config)
• sshfs
  -o reconnect

... and constructed a command:
Apparently sshfs exits on finding the first options error. Progressively removing the erroneous options generated these errors before the mount worked:

1. fuse: unknown option `nodiratime'
2. fuse: unknown option `noiversion'
3. fuse: unknown option `rellinks'

The first two were not expected because nodiratime and noiversion are listed in the mount man page in the "FILESYSTEM INDEPENDENT MOUNT OPTIONS" section. AIUI that means all file systems support those options ... ?

The rellinks error was not expected because the documentation says rellinks is not for fuse but for the kernel ... ?

Researching sshfs "How to" pages, issue pages, blogs, bug reports and mailing list archives suggests that the problem sshfs options I used are used little or not at all ... ?

Or I have missed something in how to pass these documented options on the command line ... ?

Filesystem independent mount options refers to the native filesystems.

sshfs is a user space, non-native filesystem that doesn't have to implement everything, and in fact it can't.

The "nodiratime" isn't supported because sshfs itself doesn't support directories - it just passes any requested actions off to a remote system, which may or may not implement nodiratime itself. The same applies to the other options you list. The only options sshfs can support are those it uses, and not all of those are applicable to the remote system (such as "reconnect").

I don’t know about your problem. But I suggest to you can help from a software developer.

Thanks for the clarifying perspective, jpollard :)

I have written to the OpenSSH user mailing list about the -o rellinks error and potential documentation enhancement about the mount options.

Incidentally, since starting the thread I discovered that bash command prompt path completion does not work on an sshfs file system. For example cd <sshfs mount point>/ followed by tab and tab does not result in a list of further path components as it does for common file systems.