libufs: Avoid using param.h constants in libufs.h

MAXBSIZE is defined in param.h, which defines many other things.  To
avoid forcing all consumers of libufs.h to include param.h, let's
instead redefine it and verify the definition in inode.c.

Reviewed by:	kib
MFC after:	1 week
Differential Revision:	https://reviews.freebsd.org/D56859

lib/libufs/inode.c

@@ -48,6 +48,9 @@
 
 #include <libufs.h>
 
+_Static_assert(LIBUFS_MAXBSIZE >= MAXBSIZE,
+    "LIBUFS_MAXBSIZE must be at least MAXBSIZE");
+
 int
 getinode(struct uufsd *disk, union dinodep *dp, ino_t inum)
 {

lib/libufs/libufs.h

@@ -29,6 +29,7 @@
 
 #ifndef	__LIBUFS_H__
 #define	__LIBUFS_H__
+
 #include <stdbool.h>
 
 /*
@@ -38,6 +39,8 @@
  */
 #define LIBUFS_BUFALIGN	128
 
+#define LIBUFS_MAXBSIZE	65536
+
 /*
  * userland ufs disk.
  */
@@ -48,11 +51,11 @@ struct uufsd {
 	} d_sbunion __aligned(LIBUFS_BUFALIGN);
 	union {
 		struct cg d_cg;		/* cylinder group */
-		char d_buf[MAXBSIZE];	/* cylinder group storage */
+		char d_buf[LIBUFS_MAXBSIZE]; /* cylinder group storage */
 	} d_cgunion __aligned(LIBUFS_BUFALIGN);
 	union {
 		union dinodep d_ino[1];	/* inode block */
-		char d_inos[MAXBSIZE];	/* inode block as buffer */
+		char d_inos[LIBUFS_MAXBSIZE]; /* inode block as buffer */
 	} d_inosunion __aligned(LIBUFS_BUFALIGN);
 	const char *d_name;		/* disk name */
 	const char *d_error;		/* human readable disk error */