xfs: add a xfs_btree_ptrs_equal helper

This only has a single caller and thus might be a bit questionable,
but I think it really improves the readability of
xfs_btree_visit_block.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Darrick J. Wong <djwong@kernel.org>

Author: Christoph Hellwig

fs/xfs/libxfs/xfs_btree.c

@@ -1043,6 +1043,17 @@ xfs_btree_set_ptr_null(
 		ptr->s = cpu_to_be32(NULLAGBLOCK);
 }
 
+static inline bool
+xfs_btree_ptrs_equal(
+	struct xfs_btree_cur		*cur,
+	union xfs_btree_ptr		*ptr1,
+	union xfs_btree_ptr		*ptr2)
+{
+	if (cur->bc_ops->ptr_len == XFS_BTREE_LONG_PTR_LEN)
+		return ptr1->l == ptr2->l;
+	return ptr1->s == ptr2->s;
+}
+
 /*
  * Get/set/init sibling pointers
  */
@@ -4365,7 +4376,7 @@ xfs_btree_visit_block(
 {
 	struct xfs_btree_block		*block;
 	struct xfs_buf			*bp;
-	union xfs_btree_ptr		rptr;
+	union xfs_btree_ptr		rptr, bufptr;
 	int				error;
 
 	/* do right sibling readahead */
@@ -4388,19 +4399,12 @@ xfs_btree_visit_block(
 	 * return the same block without checking if the right sibling points
 	 * back to us and creates a cyclic reference in the btree.
 	 */
-	if (cur->bc_ops->ptr_len == XFS_BTREE_LONG_PTR_LEN) {
-		if (be64_to_cpu(rptr.l) == XFS_DADDR_TO_FSB(cur->bc_mp,
-							xfs_buf_daddr(bp))) {
-			xfs_btree_mark_sick(cur);
-			return -EFSCORRUPTED;
-		}
-	} else {
-		if (be32_to_cpu(rptr.s) == xfs_daddr_to_agbno(cur->bc_mp,
-							xfs_buf_daddr(bp))) {
-			xfs_btree_mark_sick(cur);
-			return -EFSCORRUPTED;
-		}
+	xfs_btree_buf_to_ptr(cur, bp, &bufptr);
+	if (xfs_btree_ptrs_equal(cur, &rptr, &bufptr)) {
+		xfs_btree_mark_sick(cur);
+		return -EFSCORRUPTED;
 	}
+
 	return xfs_btree_lookup_get_block(cur, level, &rptr, &block);
 }