Re: [PATCH 12/15] VFS: Add owner-filesystem positive/negative dentry checks

From: David Howells
Date: Fri Mar 27 2015 - 10:42:48 EST


Miklos Szeredi <miklos@xxxxxxxxxx> wrote:

> I think this is confusing as hell, there needs to be more consistency
> in the naming. E.g. d_backing_is_positive() vs. d_is_positive(). I
> know it's the other way round now, but only with a few users.

Yeah. The problem is that all of:

__d_entry_type()
d_is_miss()
d_is_whiteout()
d_can_lookup()
d_is_autodir()
d_is_dir()
d_is_symlink()
d_is_reg()
d_is_special()
d_is_file()
d_is_negative()
d_is_positive()

refer to the 'backing' inode (if there is one) in the case that you have a
unionmount and the top dentry's ->d_inode is NULL. (Well, technically, that
doesn't happen in the case of directories)

Of course, if we decide we aren't going to do unionmount, certain things
become simpler.

> Also a separate include file might help, that needs explicit including to
> get the "backing" variants

I would like to see a 'for fs implementer' header and a 'for fs user' header
but Al didn't like that last time I suggested it.

However, it doesn't help with the naming since there are situations where you
need *both* - eg. overlayfs.

> and which would have big fat warnings all over.

Well, we could argue about which side should have the warnings.

David
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