Re: statfs() / statvfs() syscall ballsup...

[Jamie Lokier <jamie@shareable.org>]

viro@parcelfarce.linux.theplanet.co.uk wrote:
> Umm...  I don't see anything equivalent to statfs(2) ->f_type in statvfs(2).
> ->f_frsize makes no sense for practically all filesystems we support.
> ->f_namemax is not well-defined ("maximum filename length" as in "you won't
> see filenames longer than..." or "attempt to create a file with name longer
> than... will fail" or "longer than that and I'm truncating";  and that is
> aside of lovely questions about the meaning of "length" - strlen()?  number
> of multibyte characters accepted by that fs? something else?)
> ->f_fsid is also practically undefined (and left 0 by practically every fs,
> so no userland code can do anything useful with it).
> ->f_flag might be useful, all right.  However, I'd like to see real-world
> examples of code (Solaris, whatever) that would use it in any meaningful
> way...

On this theme, I'd like to know:

    - are dnotify / lease / lock reliable indicators on this filesystem?
      (i.e. dnotify is reliable on all local filesystems, but not over any
      of the remote ones AFAIK).

    - is stat() reliable (local filesystems and many remote) or potentially
      out of date without open/close (NFS due to attribute cacheing)

-- Jamie