Re: [patch 4/8] fs, exportfs: Add export_encode_inode_fh helper

On Thu, Aug 16, 2012 at 06:57:00PM +0400, Cyrill Gorcunov wrote:

Guys, would the patch below be more-less acceptible?
In inotify I think we could pass "parent" as NULL and use general
encode engine then (ie it will look like someone called for
name_to_handle_at on inotify target).

Wait.  What the hell are you going to do with those afterwards?
Again, there's a shitload of filesystems that cannot be exported
over NFS, exactly because there's no way to implement sanely
working fhandles.  And idiotify is allowed for all of them.

You *can't* decode anything fhandle-like on e.g. sysfs.  Or procfs.
Or configfs.  Or any network filesystem (I'd argue that we should simply
ban idiotify on those, but good luck doing that).  You *can* do that
for FAT derivatives, but only if you have parent directory when creating
that sucker.