[PATCH 20/47] xfs: increase XFS_BTREE_MAXLEVELS to fit the rmapbt

Darrick J. Wong
2016-07-21T04:58:24Z

By my calculations, a 1,073,741,824 block AG with a 1k block size
can attain a maximum height of 9. Assuming a record size of 24
bytes, a key/ptr size of 44 bytes, and half-full btree nodes,
we'd need 53,687,092 blocks for the records and ~6 million blocks
for the keys. That requires a btree of height 9.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
---
fs/xfs/libxfs/xfs_btree.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/xfs/libxfs/xfs_btree.h b/fs/xfs/libxfs/xfs_btree.h
index b8bbb21..629ef4f 100644
--- a/fs/xfs/libxfs/xfs_btree.h
+++ b/fs/xfs/libxfs/xfs_btree.h
@@ -133,7 +133,7 @@ do { \
} \
} while (0)

-#define XFS_BTREE_MAXLEVELS 8 /* max of all btrees */
+#define XFS_BTREE_MAXLEVELS 9 /* max of all btrees */

struct xfs_btree_ops {
/* size of the key and record structures */