VFS/FS: replace protocol version with flag field

The main motivation for this change is that only Loris supports
multithreading, and Loris supports dynamic thread allocation, so the
number of supported threads can be implemented as a bit flag (i.e.,
either 1 or "at least as many as VFS has"). The ABI break obviates the
need to support file system versioning at this time, and several
other aspects are better implemented as flags as well. Other changes:

- replace peek/bpeek test upon mount with FS flag as well;
- mark libsffs as 64-bit file size capable;
- remove old (3.2.1) getdents support.

Change-Id: I313eace9c50ed816656c31cd47d969033d952a03

include/minix/vfsif.h

@@ -39,8 +39,6 @@
 #define REQ_TRC_START_LO	m9_l3
 #define REQ_UCRED_SIZE		m9_s4 
 #define REQ_UID			m9_s4
-#define REQ_PROTO		m9_s4	/* For definition see RES_PROTO */
-
 
 /* VFS/FS reply fields */
 #define RES_DEV			m9_l4
@@ -55,35 +53,12 @@
 #define RES_SEEK_POS_LO		m9_l4
 #define RES_SYMLOOP		m9_s3
 #define RES_UID			m9_s4
-
-#define RES_PROTO		m9_s3
-/* RES_PROTO is defined as follows:
- *  |--------------------------------|
- *                   8O7 V   4  CR   0
- *  15                               0
- * mentioned bits are inclusive
- * CR: bits 4-0 encode no. concurrent requests are supported by FS
- * V:  bits 7-5 encode version of protocol
- * O:  bit 8 encodes support for 64-bit file offsets
- */
-#define RES_PROTO_CR_SHIFT	0
-#define RES_PROTO_CR_MASK	0x1F
-#define VFS_FS_PROTO_CONREQS(b)	(((b) & RES_PROTO_CR_MASK)>>RES_PROTO_CR_SHIFT)
-#define VFS_FS_PROTO_PUT_CONREQS(b,v) \
-	((b) |= (((v) << RES_PROTO_CR_SHIFT) & RES_PROTO_CR_MASK))
-#define RES_PROTO_V_SHIFT	5
-#define RES_PROTO_V_MASK	0x70
-#define VFS_FS_PROTO_VERSION(b)	(((b) & RES_PROTO_V_MASK) >> RES_PROTO_V_SHIFT)
-#define VFS_FS_PROTO_PUT_VERSION(b,v) \
-	((b) |= (((v) << RES_PROTO_V_SHIFT) & RES_PROTO_V_MASK))
-#define VFS_FS_CURRENT_VERSION	1 /* Current version */
-#define RES_PROTO_BIGOFFT_SHIFT 8
-#define VFS_FS_PROTO_BIGOFFT(b) (b & RES_PROTO_BIGOFFT_SHIFT)
+#define	RES_FLAGS		m9_s3
 
 /* VFS/FS flags */
-#define REQ_RDONLY		001
-#define REQ_ISROOT		002
-#define REQ_HASPROTO		004
+#define REQ_RDONLY		001	/* FS is mounted read-only */
+#define REQ_ISROOT		002	/* FS is root file system */
+
 #define PATH_NOFLAGS		000
 #define PATH_RET_SYMLINK	010	/* Return a symlink object (i.e.
 					 * do not continue with the contents
@@ -93,6 +68,11 @@
 					 * and struct ucred size in m9_s4 (as
 					 * opposed to a REQ_UID). */
 
+#define RES_NOFLAGS		000
+#define RES_THREADED		001	/* FS supports multithreading */
+#define RES_HASPEEK		002	/* FS implements REQ_PEEK/REQ_BPEEK */
+#define RES_64BIT		004	/* FS can handle 64-bit file sizes */
+
 /* VFS/FS error messages */
 #define EENTERMOUNT              (-301)
 #define ELEAVEMOUNT              (-302)