xfs: add support for large btree blocks

Add support for larger btree blocks that contains a CRC32C checksum,
a filesystem uuid and block number for detecting filesystem
consistency and out of place writes.

[dchinner@redhat.com] Also include an owner field to allow reverse
mappings to be implemented for improved repairability and a LSN
field to so that log recovery can easily determine the last
modification that made it to disk for each buffer.

[dchinner@redhat.com] Add buffer log format flags to indicate the
type of buffer to recovery so that we don't have to do blind magic
number tests to determine what the buffer is.

[dchinner@redhat.com] Modified to fit into the verifier structure.

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

diff --git a/fs/xfs/xfs_buf_item.h b/fs/xfs/xfs_buf_item.h
index ee36c88..101ef83 100644
--- a/fs/xfs/xfs_buf_item.h
+++ b/fs/xfs/xfs_buf_item.h
@@ -24,19 +24,33 @@
  * This flag indicates that the buffer contains on disk inodes
  * and requires special recovery handling.
  */
-#define	XFS_BLF_INODE_BUF	0x1
+#define	XFS_BLF_INODE_BUF	(1<<0)
 /*
  * This flag indicates that the buffer should not be replayed
  * during recovery because its blocks are being freed.
  */
-#define	XFS_BLF_CANCEL		0x2
+#define	XFS_BLF_CANCEL		(1<<1)
+
 /*
  * This flag indicates that the buffer contains on disk
  * user or group dquots and may require special recovery handling.
  */
-#define	XFS_BLF_UDQUOT_BUF	0x4
-#define XFS_BLF_PDQUOT_BUF	0x8
-#define	XFS_BLF_GDQUOT_BUF	0x10
+#define	XFS_BLF_UDQUOT_BUF	(1<<2)
+#define XFS_BLF_PDQUOT_BUF	(1<<3)
+#define	XFS_BLF_GDQUOT_BUF	(1<<4)
+
+/*
+ * all buffers now need flags to tell recovery where the magic number
+ * is so that it can verify and calculate the CRCs on the buffer correctly
+ * once the changes have been replayed into the buffer.
+ */
+#define XFS_BLF_BTREE_BUF	(1<<5)
+
+#define XFS_BLF_TYPE_MASK	\
+		(XFS_BLF_UDQUOT_BUF | \
+		 XFS_BLF_PDQUOT_BUF | \
+		 XFS_BLF_GDQUOT_BUF | \
+		 XFS_BLF_BTREE_BUF)
 
 #define	XFS_BLF_CHUNK		128
 #define	XFS_BLF_SHIFT		7