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>

1 files changed, 55 insertions, 9 deletions

diff --git a/fs/xfs/xfs_btree.h b/fs/xfs/xfs_btree.h
index f932897194eb..6e6c915673fe 100644
--- a/fs/xfs/xfs_btree.h
+++ b/fs/xfs/xfs_btree.h
@@ -42,11 +42,15 @@ extern kmem_zone_t	*xfs_btree_cur_zone;
  * Generic btree header.
  *
  * This is a combination of the actual format used on disk for short and long
- * format btrees.  The first three fields are shared by both format, but
- * the pointers are different and should be used with care.
+ * format btrees.  The first three fields are shared by both format, but the
+ * pointers are different and should be used with care.
  *
- * To get the size of the actual short or long form headers please use
- * the size macros below.  Never use sizeof(xfs_btree_block).
+ * To get the size of the actual short or long form headers please use the size
+ * macros below.  Never use sizeof(xfs_btree_block).
+ *
+ * The blkno, crc, lsn, owner and uuid fields are only available in filesystems
+ * with the crc feature bit, and all accesses to them must be conditional on
+ * that flag.
  */
 struct xfs_btree_block {
 	__be32		bb_magic;	/* magic number for block type */
@@ -56,10 +60,23 @@ struct xfs_btree_block {
 		struct {
 			__be32		bb_leftsib;
 			__be32		bb_rightsib;
+
+			__be64		bb_blkno;
+			__be64		bb_lsn;
+			uuid_t		bb_uuid;
+			__be32		bb_owner;
+			__le32		bb_crc;
 		} s;			/* short form pointers */
 		struct	{
 			__be64		bb_leftsib;
 			__be64		bb_rightsib;
+
+			__be64		bb_blkno;
+			__be64		bb_lsn;
+			uuid_t		bb_uuid;
+			__be64		bb_owner;
+			__le32		bb_crc;
+			__be32		bb_pad; /* padding for alignment */
 		} l;			/* long form pointers */
 	} bb_u;				/* rest */
 };
@@ -67,6 +84,16 @@ struct xfs_btree_block {
 #define XFS_BTREE_SBLOCK_LEN	16	/* size of a short form block */
 #define XFS_BTREE_LBLOCK_LEN	24	/* size of a long form block */
 
+/* sizes of CRC enabled btree blocks */
+#define XFS_BTREE_SBLOCK_CRC_LEN	(XFS_BTREE_SBLOCK_LEN + 40)
+#define XFS_BTREE_LBLOCK_CRC_LEN	(XFS_BTREE_LBLOCK_LEN + 48)
+
+
+#define XFS_BTREE_SBLOCK_CRC_OFF \
+	offsetof(struct xfs_btree_block, bb_u.s.bb_crc)
+#define XFS_BTREE_LBLOCK_CRC_OFF \
+	offsetof(struct xfs_btree_block, bb_u.l.bb_crc)
+
 
 /*
  * Generic key, ptr and record wrapper structures.
@@ -101,13 +128,11 @@ union xfs_btree_rec {
 #define	XFS_BB_NUMRECS		0x04
 #define	XFS_BB_LEFTSIB		0x08
 #define	XFS_BB_RIGHTSIB		0x10
+#define	XFS_BB_BLKNO		0x20
 #define	XFS_BB_NUM_BITS		5
 #define	XFS_BB_ALL_BITS		((1 << XFS_BB_NUM_BITS) - 1)
-
-/*
- * Magic numbers for btree blocks.
- */
-extern const __uint32_t	xfs_magics[];
+#define	XFS_BB_NUM_BITS_CRC	8
+#define	XFS_BB_ALL_BITS_CRC	((1 << XFS_BB_NUM_BITS_CRC) - 1)
 
 /*
  * Generic stats interface
@@ -256,6 +281,7 @@ typedef struct xfs_btree_cur
 #define XFS_BTREE_LONG_PTRS		(1<<0)	/* pointers are 64bits long */
 #define XFS_BTREE_ROOT_IN_INODE		(1<<1)	/* root may be variable size */
 #define XFS_BTREE_LASTREC_UPDATE	(1<<2)	/* track last rec externally */
+#define XFS_BTREE_CRC_BLOCKS		(1<<3)	/* uses extended btree blocks */
 
 
 #define	XFS_BTREE_NOERROR	0
@@ -393,8 +419,20 @@ xfs_btree_init_block(
 	__u32		magic,
 	__u16		level,
 	__u16		numrecs,
+	__u64		owner,
 	unsigned int	flags);
 
+void
+xfs_btree_init_block_int(
+	struct xfs_mount	*mp,
+	struct xfs_btree_block	*buf,
+	xfs_daddr_t		blkno,
+	__u32			magic,
+	__u16			level,
+	__u16			numrecs,
+	__u64			owner,
+	unsigned int		flags);
+
 /*
  * Common btree core entry points.
  */
@@ -408,6 +446,14 @@ int xfs_btree_delete(struct xfs_btree_cur *, int *);
 int xfs_btree_get_rec(struct xfs_btree_cur *, union xfs_btree_rec **, int *);
 
 /*
+ * btree block CRC helpers
+ */
+void xfs_btree_lblock_calc_crc(struct xfs_buf *);
+bool xfs_btree_lblock_verify_crc(struct xfs_buf *);
+void xfs_btree_sblock_calc_crc(struct xfs_buf *);
+bool xfs_btree_sblock_verify_crc(struct xfs_buf *);
+
+/*
  * Internal btree helpers also used by xfs_bmap.c.
  */
 void xfs_btree_log_block(struct xfs_btree_cur *, struct xfs_buf *, int);