iget: stop CIFS from using iget() and read_inode()

Stop the CIFS filesystem from using iget() and read_inode().  Replace
cifs_read_inode() with cifs_iget(), and call that instead of iget().
cifs_iget() then uses iget_locked() directly and returns a proper error code
instead of an inode in the event of an error.

cifs_read_super() now returns any error incurred when getting the root inode
instead of ENOMEM.

cifs_iget() needs examining.  The comment "can not call macro FreeXid here
since in a void func" is no longer true.

Signed-off-by: David Howells <dhowells@redhat.com>
Cc: Steven French <sfrench@us.ibm.com>
Acked-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/fs/cifs/cifsfs.h b/fs/cifs/cifsfs.h
index 195b14d..6897830 100644
--- a/fs/cifs/cifsfs.h
+++ b/fs/cifs/cifsfs.h
@@ -44,6 +44,7 @@
 
 /* Functions related to inodes */
 extern const struct inode_operations cifs_dir_inode_ops;
+extern struct inode *cifs_iget(struct super_block *, unsigned long);
 extern int cifs_create(struct inode *, struct dentry *, int,
 		       struct nameidata *);
 extern struct dentry *cifs_lookup(struct inode *, struct dentry *,