xfs: define the on-disk rmap btree format

Originally-From: Dave Chinner <dchinner@redhat.com>

Now we have all the surrounding call infrastructure in place, we can
start filling out the rmap btree implementation. Start with the
on-disk btree format; add everything needed to read, write and
manipulate rmap btree blocks. This prepares the way for adding the
btree operations implementation.

[darrick: record owner and offset info in rmap btree]
[darrick: fork, bmbt and unwritten state in rmap btree]
[darrick: flags are a separate field in xfs_rmap_irec]
[darrick: calculate maxlevels separately]
[darrick: move the 'unwritten' bit into unused parts of rm_offset]

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>

1 files changed, 67 insertions, 0 deletions

diff --git a/fs/xfs/libxfs/xfs_rmap.h b/fs/xfs/libxfs/xfs_rmap.h
index dbf0301e9ae1..e7a670459fea 100644
--- a/fs/xfs/libxfs/xfs_rmap.h
+++ b/fs/xfs/libxfs/xfs_rmap.h
@@ -68,6 +68,73 @@ xfs_rmap_skip_owner_update(
 
 struct xfs_buf;
 
+static inline __u64
+xfs_rmap_irec_offset_pack(
+	const struct xfs_rmap_irec	*irec)
+{
+	__u64			x;
+
+	x = XFS_RMAP_OFF(irec->rm_offset);
+	if (irec->rm_flags & XFS_RMAP_ATTR_FORK)
+		x |= XFS_RMAP_OFF_ATTR_FORK;
+	if (irec->rm_flags & XFS_RMAP_BMBT_BLOCK)
+		x |= XFS_RMAP_OFF_BMBT_BLOCK;
+	if (irec->rm_flags & XFS_RMAP_UNWRITTEN)
+		x |= XFS_RMAP_OFF_UNWRITTEN;
+	return x;
+}
+
+static inline int
+xfs_rmap_irec_offset_unpack(
+	__u64			offset,
+	struct xfs_rmap_irec	*irec)
+{
+	if (offset & ~(XFS_RMAP_OFF_MASK | XFS_RMAP_OFF_FLAGS))
+		return -EFSCORRUPTED;
+	irec->rm_offset = XFS_RMAP_OFF(offset);
+	if (offset & XFS_RMAP_OFF_ATTR_FORK)
+		irec->rm_flags |= XFS_RMAP_ATTR_FORK;
+	if (offset & XFS_RMAP_OFF_BMBT_BLOCK)
+		irec->rm_flags |= XFS_RMAP_BMBT_BLOCK;
+	if (offset & XFS_RMAP_OFF_UNWRITTEN)
+		irec->rm_flags |= XFS_RMAP_UNWRITTEN;
+	return 0;
+}
+
+static inline void
+xfs_owner_info_unpack(
+	struct xfs_owner_info	*oinfo,
+	uint64_t		*owner,
+	uint64_t		*offset,
+	unsigned int		*flags)
+{
+	unsigned int		r = 0;
+
+	*owner = oinfo->oi_owner;
+	*offset = oinfo->oi_offset;
+	if (oinfo->oi_flags & XFS_OWNER_INFO_ATTR_FORK)
+		r |= XFS_RMAP_ATTR_FORK;
+	if (oinfo->oi_flags & XFS_OWNER_INFO_BMBT_BLOCK)
+		r |= XFS_RMAP_BMBT_BLOCK;
+	*flags = r;
+}
+
+static inline void
+xfs_owner_info_pack(
+	struct xfs_owner_info	*oinfo,
+	uint64_t		owner,
+	uint64_t		offset,
+	unsigned int		flags)
+{
+	oinfo->oi_owner = owner;
+	oinfo->oi_offset = XFS_RMAP_OFF(offset);
+	oinfo->oi_flags = 0;
+	if (flags & XFS_RMAP_ATTR_FORK)
+		oinfo->oi_flags |= XFS_OWNER_INFO_ATTR_FORK;
+	if (flags & XFS_RMAP_BMBT_BLOCK)
+		oinfo->oi_flags |= XFS_OWNER_INFO_BMBT_BLOCK;
+}
+
 int xfs_rmap_alloc(struct xfs_trans *tp, struct xfs_buf *agbp,
 		   xfs_agnumber_t agno, xfs_agblock_t bno, xfs_extlen_t len,
 		   struct xfs_owner_info *oinfo);