xfs: make the pointer passed to btree set_root functions const

The pointer passed to each per-AG btree type's ->set_root function isn't
supposed to be modified (that function sets an external pointer to the
root block) so mark them const.
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>

fs/xfs/libxfs/xfs_alloc_btree.c

@@ -31,9 +31,9 @@ xfs_allocbt_dup_cursor(
 
 STATIC void
 xfs_allocbt_set_root(
-	struct xfs_btree_cur	*cur,
-	union xfs_btree_ptr	*ptr,
-	int			inc)
+	struct xfs_btree_cur		*cur,
+	const union xfs_btree_ptr	*ptr,
+	int				inc)
 {
 	struct xfs_buf		*agbp = cur->bc_ag.agbp;
 	struct xfs_agf		*agf = agbp->b_addr;

fs/xfs/libxfs/xfs_btree.h

@@ -106,7 +106,7 @@ struct xfs_btree_ops {
 
 	/* update btree root pointer */
 	void	(*set_root)(struct xfs_btree_cur *cur,
-			    union xfs_btree_ptr *nptr, int level_change);
+			    const union xfs_btree_ptr *nptr, int level_change);
 
 	/* block allocation / freeing */
 	int	(*alloc_block)(struct xfs_btree_cur *cur,

fs/xfs/libxfs/xfs_btree_staging.c

@@ -112,9 +112,9 @@ xfs_btree_fakeroot_init_ptr_from_cur(
 /* Update the btree root information for a per-AG fake root. */
 STATIC void
 xfs_btree_afakeroot_set_root(
-	struct xfs_btree_cur	*cur,
-	union xfs_btree_ptr	*ptr,
-	int			inc)
+	struct xfs_btree_cur		*cur,
+	const union xfs_btree_ptr	*ptr,
+	int				inc)
 {
 	struct xbtree_afakeroot	*afake = cur->bc_ag.afake;
 

fs/xfs/libxfs/xfs_ialloc_btree.c

@@ -40,9 +40,9 @@ xfs_inobt_dup_cursor(
 
 STATIC void
 xfs_inobt_set_root(
-	struct xfs_btree_cur	*cur,
-	union xfs_btree_ptr	*nptr,
-	int			inc)	/* level change */
+	struct xfs_btree_cur		*cur,
+	const union xfs_btree_ptr	*nptr,
+	int				inc)	/* level change */
 {
 	struct xfs_buf		*agbp = cur->bc_ag.agbp;
 	struct xfs_agi		*agi = agbp->b_addr;
@@ -54,9 +54,9 @@ xfs_inobt_set_root(
 
 STATIC void
 xfs_finobt_set_root(
-	struct xfs_btree_cur	*cur,
-	union xfs_btree_ptr	*nptr,
-	int			inc)	/* level change */
+	struct xfs_btree_cur		*cur,
+	const union xfs_btree_ptr	*nptr,
+	int				inc)	/* level change */
 {
 	struct xfs_buf		*agbp = cur->bc_ag.agbp;
 	struct xfs_agi		*agi = agbp->b_addr;

fs/xfs/libxfs/xfs_refcount_btree.c

@@ -31,9 +31,9 @@ xfs_refcountbt_dup_cursor(
 
 STATIC void
 xfs_refcountbt_set_root(
-	struct xfs_btree_cur	*cur,
-	union xfs_btree_ptr	*ptr,
-	int			inc)
+	struct xfs_btree_cur		*cur,
+	const union xfs_btree_ptr	*ptr,
+	int				inc)
 {
 	struct xfs_buf		*agbp = cur->bc_ag.agbp;
 	struct xfs_agf		*agf = agbp->b_addr;

fs/xfs/libxfs/xfs_rmap_btree.c

@@ -57,9 +57,9 @@ xfs_rmapbt_dup_cursor(
 
 STATIC void
 xfs_rmapbt_set_root(
-	struct xfs_btree_cur	*cur,
-	union xfs_btree_ptr	*ptr,
-	int			inc)
+	struct xfs_btree_cur		*cur,
+	const union xfs_btree_ptr	*ptr,
+	int				inc)
 {
 	struct xfs_buf		*agbp = cur->bc_ag.agbp;
 	struct xfs_agf		*agf = agbp->b_addr;