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

On Thu, Aug 16, 2012 at 03:55:27PM +0100, Al Viro wrote:

On Thu, Aug 16, 2012 at 06:48:35PM +0400, Cyrill Gorcunov wrote:

quoted

quoted

Good luck doing that with e.g. VFAT...  And then there's such thing
as filesystems that don't have ->encode_fh() for a lot of very good

Wait, Al, it seems I messed up. If some fs has no encode_fh() implemented
the default encoding with FILEID_INO32_GEN_PARENT will be used for that.

... which doesn't work for a lot of filesystems.  Not if you want to be
able to decode the result afterwards and get something useful out of
that.  Trying to implement ->fh_to_dentry(), especially with fhandle
generated by inode alone is going to be really interesting for a bunch
of stuff...

hmm, yup (and Bruce just pointed me to exportfs_decode_fh). So, if fs doesn't
provide encode_fh (and decode as well) but the FILEID_INO32_GEN_PARENT used
instead, we will not be able to restore such inotify later. Then I suppose
such application will be unrestorable at least for a while. Would not this
be acceptable trade off?

	Cyrill