cifs: always update the inode cache with the results from a FIND_*

commit cd60042c upstream.

When we get back a FIND_FIRST/NEXT result, we have some info about the
dentry that we use to instantiate a new inode. We were ignoring and
discarding that info when we had an existing dentry in the cache.

Fix this by updating the inode in place when we find an existing dentry
and the uniqueid is the same.
Reported-and-Tested-by: Andrew Bartlett <abartlet@samba.org>
Reported-by: Bill Robertson <bill_robertson@debortoli.com.au>
Reported-by: Dion Edwards <dion_edwards@debortoli.com.au>
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <smfrench@gmail.com>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

fs/cifs/readdir.c

@@ -86,9 +86,12 @@ cifs_readdir_lookup(struct dentry *parent, struct qstr *name,
 
 	dentry = d_lookup(parent, name);
 	if (dentry) {
-		/* FIXME: check for inode number changes? */
-		if (dentry->d_inode != NULL)
+		inode = dentry->d_inode;
+		/* update inode in place if i_ino didn't change */
+		if (inode && CIFS_I(inode)->uniqueid == fattr->cf_uniqueid) {
+			cifs_fattr_to_inode(inode, fattr);
 			return dentry;
+		}
 		d_drop(dentry);
 		dput(dentry);
 	}