xfs: remove the global xfs_Gqm structure

If we initialize the slab caches for the quota code when XFS is loaded there
is no need for a global and reference counted quota manager structure.  Drop
all this overhead and also fix the error handling during quota initialization.

Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Ben Myers <bpm@sgi.com>

diff --git a/fs/xfs/xfs_super.h b/fs/xfs/xfs_super.h
index 50a3266..09b0c26 100644
--- a/fs/xfs/xfs_super.h
+++ b/fs/xfs/xfs_super.h
@@ -21,13 +21,11 @@
 #include <linux/exportfs.h>
 
 #ifdef CONFIG_XFS_QUOTA
-extern void xfs_qm_init(void);
+extern int xfs_qm_init(void);
 extern void xfs_qm_exit(void);
-# define vfs_initquota()	xfs_qm_init()
-# define vfs_exitquota()	xfs_qm_exit()
 #else
-# define vfs_initquota()	do { } while (0)
-# define vfs_exitquota()	do { } while (0)
+# define xfs_qm_init()	(0)
+# define xfs_qm_exit()	do { } while (0)
 #endif
 
 #ifdef CONFIG_XFS_POSIX_ACL