Re: [PATCH 04/11] vfs: add renameat2 syscall

From: Miklos Szeredi
Date: Wed Jan 15 2014 - 05:29:49 EST


On Wed, Jan 15, 2014 at 07:11:16AM +0900, Tetsuo Handa wrote:
> Miklos Szeredi wrote:
> > +
> > + if (flags)
> > + return -EOPNOTSUPP;
> > +
>
> If (at least for now) only ext4 interprets renameat2() flags,
> I think adding a new member to "struct inode_operations" and
> check it like
>
> if (!old_dir->i_op->swapname)
> return -EOPNOTSUPP;
>
> or

This is not just about swapname, but other rename variants too (non-overwriting
rename is also included in the patchset).

>
> if (!(old_dir->i_op->supported_features & flags))
> return -EOPNOTSUPP;

Or rather old_dir->i_sb->s_type->fs_flags. We access it due to
FS_RENAME_DOES_D_MOVE anyway.

I like this variant, because now filesystems need to explicitly add a flag to
*enable* the functionality and not a check to disable it.

Objections?

Thanks,
Miklos
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