[XFS] Merge max file offset fix - use standard Linux macros

SGI Modid: 2.5.x-xfs:slinx:135881a

fs/xfs/linux/xfs_linux.h

@@ -42,6 +42,7 @@
 #include <linux/sched.h>
 #include <linux/bitops.h>
 #include <linux/major.h>
+#include <linux/pagemap.h>
 #include <linux/vfs.h>
 
 #include <asm/page.h>

fs/xfs/xfs_inode.h

@@ -414,11 +414,9 @@ void xfs_ifork_next_set(xfs_inode_t *ip, int w, int n);
  * max file offset is 2^(31+PAGE_SHIFT) - 1 (due to linux page cache)
  *
  * NOTE: XFS itself can handle 2^63 - 1 (largest positive value of xfs_fsize_t)
- * but Linux can't go above 2^(31+PAGE_SHIFT)-1: the Linux VM uses a 32 bit
- * signed variable to index cache data, so 2^31 * PAGE_SIZE is as big as
- * you can go.
+ * but this is the Linux limit.
  */
-#define XFS_MAX_FILE_OFFSET	((long long)((1ULL<<(31+PAGE_SHIFT))-1ULL))
+#define XFS_MAX_FILE_OFFSET	MAX_LFS_FILESIZE
 
 #if XFS_WANT_FUNCS || (XFS_WANT_SPACE && XFSSO_XFS_ITOV)
 struct vnode *xfs_itov(xfs_inode_t *ip);