On Wed, 2017-02-15 at 15:34 -0500, Vivek Goyal wrote:
> On Sat, Feb 04, 2017 at 11:19:32AM -0800, James Bottomley wrote:
>
> [..]
> > +static struct dentry *shiftfs_lookup(struct inode *dir, struct
> > dentry *dentry,
> > + unsigned int flags)
> > +{
> > + struct dentry *real = dir->i_private, *new;
> > + struct inode *reali = real->d_inode, *newi;
> > + const struct cred *oldcred, *newcred;
> > +
> > + inode_lock(reali);
> > + oldcred = shiftfs_new_creds(&newcred, dentry->d_sb);
> > + new = lookup_one_len(dentry->d_name.name, real, dentry
> > ->d_name.len);
> > + shiftfs_old_creds(oldcred, &newcred);
> > + inode_unlock(reali);
> > +
> > + if (IS_ERR(new))
> > + return new;
> > +
> > + dentry->d_fsdata = new;
> > +
> > + if (!new->d_inode)
> > + return NULL;
> > +
> > + newi = shiftfs_new_inode(dentry->d_sb, new->d_inode
> > ->i_mode, new);
> > + if (!newi) {
> > + dput(new);
> > + return ERR_PTR(-ENOMEM);
> > + }
> > +
> > + d_splice_alias(newi, dentry);
>
> Hi James,
>
> Should it be "return d_splice_alias()" so that if we find an alias it
> is returned back to caller and passed in dentry can be freed. Though
> I don't know in what cases alias can be found. And if alias is found
> how do we make sure alias_dentry->d_fsdata is pointing to new (real
> dentry).
It probably should be for the sake of the pattern. In our case I don't
think we can have any root aliases because the root dentry is always
pinned in the cache, so cache lookup should always find it.
James
