[XFS] Fix up sparse warnings.

These are mostly locking annotations, marking things static, casts where
needed and declaring stuff in header files.

SGI-PV: 971186
SGI-Modid: xfs-linux-melb:xfs-kern:30002a

Signed-off-by: David Chinner <dgc@sgi.com>
Signed-off-by: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Lachlan McIlroy <lachlan@sgi.com>
diff --git a/fs/xfs/xfs_trans.h b/fs/xfs/xfs_trans.h
index 0e26e72..bea6e2b 100644
--- a/fs/xfs/xfs_trans.h
+++ b/fs/xfs/xfs_trans.h
@@ -1001,6 +1001,8 @@
 					xfs_agnumber_t ag,
 					xfs_extlen_t idx);
 
+extern kmem_zone_t	*xfs_trans_zone;
+
 #endif	/* __KERNEL__ */
 
 #endif	/* __XFS_TRANS_H__ */