[PATCH 4/6] ubifs: Maintain a parent pointer

[Richard Weinberger]

Christoph,

Am 23.05.2017 um 10:37 schrieb Christoph Hellwig:
> On Sun, May 21, 2017 at 10:20:49PM +0200, Richard Weinberger wrote:
>> The new feature UBIFS_FLG_PARENTPOINTER allows looking
>> up the parent. Usually the Linux VFS walks down the filesystem
>> and no parent pointers are needed. But when a filesystem
>> is exportable via NFS such a lookup is needed.
>> We can use a padding field in struct ubifs_ino_node to
>> maintain a pointer to the parent inode.
> 
> Note that nfsd/exportfs will only do this for directories, and beacause
> we hardlinks for other objects that is an important distinction.
> 
> I think the ubifs code should make sure to only maintain the parent
> pointers for directories, otherwise confusion and abuses will happen.

Thanks for the info, I'll massage the code in that direction.

Thanks,
//richard