Don't pass inode to ->d_hash() and ->d_compare()

Instances either don't look at it at all (the majority of cases) or
only want it to find the superblock (which can be had as dentry->d_sb).
A few cases that want more are actually safe with dentry->d_inode -
the only precaution needed is the check that it hadn't been replaced with
NULL by rmdir() or by overwriting rename(), which case should be simply
treated as cache miss.

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

Documentation/filesystems/Locking

@@ -11,10 +11,8 @@ be able to use diff(1).
 prototypes:
 	int (*d_revalidate)(struct dentry *, unsigned int);
 	int (*d_weak_revalidate)(struct dentry *, unsigned int);
-	int (*d_hash)(const struct dentry *, const struct inode *,
-			struct qstr *);
-	int (*d_compare)(const struct dentry *, const struct inode *,
-			const struct dentry *, const struct inode *,
+	int (*d_hash)(const struct dentry *, struct qstr *);
+	int (*d_compare)(const struct dentry *, const struct dentry *,
 			unsigned int, const char *, const struct qstr *);
 	int (*d_delete)(struct dentry *);
 	void (*d_release)(struct dentry *);