[CIFS] revalidate parent inode when rmdir done within that directory

When a search is pending of a parent directory, and a child directory
within it is removed, we need to reset the parent directory's time
so that we don't reuse the (now stale) search results.

Thanks to Gunter Kukkukk for reporting this:

> got the following failure notification on irc #samba:
>
> A user was updating from subversion 1.4 to 1.5, where the
> repository is located on a samba share (independent of
> unix extensions = Yes or No).
> svn 1.4 did work, 1.5 does not.
>
> The user did a lot of stracing of subversion - and wrote a
> testapplet to simulate the failing behaviour.
> I've converted the C++ source to C and added some error cases.
>
> When using "./testdir" on a local file system, "result2"
> is always (nil) as expected - cifs vfs behaves different here!
>
>   ./testdir /mnt/cifs/mounted/share
>
> returns a (failing) valid pointer.

Acked-by: Dave Kleikamp <shaggy@us.ibm.com>
Acked-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>

fs/cifs/CHANGES

@@ -5,7 +5,9 @@ rather than posix (advisory) byte range locks, even though server would
 support posix byte range locks.  Fix query of root inode when prefixpath
 specified and user does not have access to query information about the
 top of the share.  Fix problem in 2.6.28 resolving DFS paths to
-Samba servers (worked to Windows).
+Samba servers (worked to Windows).  Fix rmdir so that pending search
+(readdir) requests do not get invalid results which include the now
+removed directory.
 
 Version 1.55
 ------------

fs/cifs/inode.c

@@ -1285,6 +1285,11 @@ int cifs_rmdir(struct inode *inode, struct dentry *direntry)
 	cifsInode = CIFS_I(direntry->d_inode);
 	cifsInode->time = 0;	/* force revalidate to go get info when
 				   needed */
+
+	cifsInode = CIFS_I(inode);
+	cifsInode->time = 0;	/* force revalidate to get parent dir info
+				   since cached search results now invalid */
+
 	direntry->d_inode->i_ctime = inode->i_ctime = inode->i_mtime =
 		current_fs_time(inode->i_sb);