[XFS] Introduce two new mount options (nolargeio/largeio) to allow
filesystems to expose the filesystem stripe width in stat(2) rather than
the page cache size. This allows applications requiring high bandwidth to
easily determine the optimum I/O size for the underlying filesystem. The
default is to report the page cache size (i.e. "nolargeio").

SGI-PV: 942818
SGI-Modid: xfs-linux:xfs-kern:23830a

Signed-off-by: David Chinner <dgc@sgi.com>
Signed-off-by: Nathan Scott <nathans@sgi.com>
diff --git a/fs/xfs/xfs_clnt.h b/fs/xfs/xfs_clnt.h
index c93cb28..90d9d56 100644
--- a/fs/xfs/xfs_clnt.h
+++ b/fs/xfs/xfs_clnt.h
@@ -106,5 +106,7 @@
 #define XFSMNT_IHASHSIZE	0x20000000	/* inode hash table size */
 #define XFSMNT_DIRSYNC		0x40000000	/* sync creat,link,unlink,rename
 						 * symlink,mkdir,rmdir,mknod */
+#define XFSMNT_COMPAT_IOSIZE	0x80000000	/* don't report large preferred
+						 * I/O size in stat() */
 
 #endif	/* __XFS_CLNT_H__ */