Mount updates:

- allow mounting with "none" block device
- allow unmounting by mountpoint
- make VFS aware of file system process labels
- allow m3_ca1 to use the full available message size
- use *printf in u/mount(1), as mount(2) uses it already
- fix reference leaks for some mount error cases in VFS

include/minix/dmap.h

@@ -11,7 +11,11 @@ enum dev_style { STYLE_DEV, STYLE_NDEV, STYLE_TTY, STYLE_CLONE };
  *===========================================================================*/
 
 /* Total number of different devices. */
-#define NR_DEVICES   		  32			/* number of (major) devices */
+#define NR_DEVICES   		  32		/* number of (major) devices */
+
+#define NONE_MAJOR		   0	/* pseudo device for mounting file
+					 * systems without a real block device
+					 */
 
 /* Major and minor device numbers for MEMORY driver. */
 #define MEMORY_MAJOR  		   1	/* major device for memory devices */

include/minix/ipc.h

@@ -10,12 +10,13 @@
 #define M1                 1
 #define M3                 3
 #define M4                 4
-#define M3_STRING         14
+#define M3_STRING         14	/* legacy m3_ca1 size (must not be changed) */
+#define M3_LONG_STRING    16	/* current m3_ca1 size (may be increased) */
 
 typedef struct {int m1i1, m1i2, m1i3; char *m1p1, *m1p2, *m1p3;} mess_1;
 typedef struct {int m2i1, m2i2, m2i3; long m2l1, m2l2; char *m2p1; 
         short m2s1;} mess_2;
-typedef struct {int m3i1, m3i2; char *m3p1; char m3ca1[M3_STRING];} mess_3;
+typedef struct {int m3i1, m3i2; char *m3p1; char m3ca1[M3_LONG_STRING];} mess_3;
 typedef struct {long m4l1, m4l2, m4l3, m4l4, m4l5;} mess_4;
 typedef struct {short m5c1, m5c2; int m5i1, m5i2; long m5l1, m5l2, m5l3;}mess_5;
 typedef struct {long m6l1, m6l2, m6l3; short m6s1, m6s2, m6s3; char m6c1, m6c2;

include/sys/mount.h

@@ -7,6 +7,7 @@
 
 #define MS_RDONLY	0x001	/* Mount device read only */
 #define MS_REUSE	0x002	/* Tell RS to try reusing binary from memory */
+#define MS_LABEL16	0x004	/* Mount message points to 16-byte label */
 
 
 /* Function Prototypes. */