xfs: add CRC infrastructure

 - add a mount feature bit for CRC enabled filesystems
 - add some helpers for generating and verifying the CRCs
 - add a copy_uuid helper

The checksumming helpers are loosely based on similar ones in sctp,
all other bits come from Dave Chinner.

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

diff --git a/fs/xfs/uuid.h b/fs/xfs/uuid.h
index 4732d71..104db0f 100644
--- a/fs/xfs/uuid.h
+++ b/fs/xfs/uuid.h
@@ -26,4 +26,10 @@
 extern int uuid_equal(uuid_t *uuid1, uuid_t *uuid2);
 extern void uuid_getnodeuniq(uuid_t *uuid, int fsid [2]);
 
+static inline void
+uuid_copy(uuid_t *dst, uuid_t *src)
+{
+	memcpy(dst, src, sizeof(uuid_t));
+}
+
 #endif	/* __XFS_SUPPORT_UUID_H__ */