Re: [PATCH 1/3] fscrypto: use dget_parent() in fscrypt_d_revalidate()

[Jaegeuk Kim]

On Tue, Apr 12, 2016 at 11:33:03PM +0100, Al Viro wrote:
> On Tue, Apr 12, 2016 at 10:27:20AM -0700, Jaegeuk Kim wrote:
> > This patch updates fscrypto along with the below ext4 crypto change.
> > 
> > Fixes: 3d43bcfef5f0 ("ext4 crypto: use dget_parent() in ext4_d_revalidate()")
> 
> >  static int fscrypt_d_revalidate(struct dentry *dentry, unsigned int flags)
> >  {
> > -	struct inode *dir = d_inode(dentry->d_parent);
> > -	struct fscrypt_info *ci = dir->i_crypt_info;
> > +	struct dentry *dir;
> > +	struct fscrypt_info *ci;
> >  	int dir_has_key, cached_with_key;
> >  
> > -	if (!dir->i_sb->s_cop->is_encrypted(dir))
> > +	dir = dget_parent(dentry);
> > +	if (!d_inode(dir)->i_sb->s_cop->is_encrypted(d_inode(dir))) {
> > +		dput(dir);
> 
> ... and as soon as you call it from RCU mode, you are screwed.

Thank you for pointing this out.
IIUC, did you mean this?

Thanks,