Hi! Currently UBIFS is not exportable. I'm not sure whether it is completely impossible or if I just miss a detail. So I've some questions. Documentation/filesystems/nfs/Exporting states that the only required function is fh_to_dentry(). This function should on UBIFS be implementable using generic_fh_to_dentry(). While UBIFS reuses in theory inode numbers we can ignore i_generation as the flash chip is long dead before we start reusing inodes. Same as for JFFS2. But the same document states also that fh_to_parent() and get_parent() are optional but strongly recommended. What does this mean? Will NFS work but puppies die and turn into zombies? Implementing get_parent() is a little unpleasant. UBIFS's on-flash layout does not support querying the parent. We could change UBIFS's struct ubifs_ino_node, but I'd change the on-flash layout only as last resort. The biggest problem I see is that UBIFS does not really support telldir() and seekdir(). Directory offsets in UBIFS are plain hash values, so telldir()/seekdir() won't correctly work if UBIFS faces hash collisions. Currently UBIFS implements a hack which stores the UBIFS dent object into file->private_data such that consecutive readdir()s are guaranteed to work. A comment on UBIFS's readdir states: * This means that UBIFS cannot support NFS which requires full * 'seekdir()'/'telldir()' support. Is this still true? Maybe we can have NFS even if it is not perfect in terms of performance. Artem, did I miss another show stopper? :-) Thanks, //richard -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
