Add block device tracing facility

The implementation is in libblockdriver, and works transparently for
all block drivers. The new btrace(8) tool can be used to control block
tracing; see ``man btrace'' for details.

common/include/Makefile.inc

@@ -6,6 +6,7 @@ INCS+=  env.h fetch.h hgfs.h lib.h libutil.h timers.h
 
 INCS+= 	minix/acpi.h minix/ansi.h minix/audio_fw.h minix/bitmap.h \
 	minix/bdev.h minix/blockdriver.h minix/blockdriver_mt.h \
+	minix/btrace.h \
 	minix/callnr.h minix/chardriver.h minix/com.h minix/compiler.h \
 	minix/config.h minix/const.h minix/cpufeature.h minix/crtso.h \
 	minix/debug.h minix/devio.h minix/devman.h minix/dmap.h \

common/include/minix/blockdriver.h

@@ -27,7 +27,7 @@ struct blockdriver {
  */
 _PROTOTYPE( void blockdriver_announce, (void) );
 
-#ifndef _DRIVER_MT_API
+#ifndef _BLOCKDRIVER_MT_API
 /* Additional functions for the singlethreaded version. These allow the driver
  * to either use the stock driver_task(), or implement its own message loop.
  * To avoid accidents, these functions are not exposed when minix/driver_mt.h
@@ -39,7 +39,7 @@ _PROTOTYPE( void blockdriver_process, (struct blockdriver *dp, message *m_ptr,
 _PROTOTYPE( void blockdriver_terminate, (void) );
 _PROTOTYPE( void blockdriver_task, (struct blockdriver *bdp) );
 _PROTOTYPE( int blockdriver_mq_queue, (message *m_ptr, int status) );
-#endif /* !_DRIVER_MT_API */
+#endif /* !_BLOCKDRIVER_MT_API */
 
 /* Parameters for the disk drive. */
 #define SECTOR_SIZE      512	/* physical sector size in bytes */

common/include/minix/blockdriver_mt.h

@@ -1,11 +1,11 @@
 #ifndef _MINIX_BLOCKDRIVER_MT_H
 #define _MINIX_BLOCKDRIVER_MT_H
 
-#define DRIVER_MT_API 1		/* do not expose the singlethreaded API */
+#define BLOCKDRIVER_MT_API 1	/* do not expose the singlethreaded API */
 #include <minix/blockdriver.h>
 
 /* The maximum number of worker threads. */
-#define DRIVER_MT_MAX_WORKERS	32
+#define BLOCKDRIVER_MT_MAX_WORKERS	32
 
 _PROTOTYPE( void blockdriver_mt_task, (struct blockdriver *driver_tab) );
 _PROTOTYPE( void blockdriver_mt_sleep, (void) );

common/include/minix/btrace.h

@@ -0,0 +1,40 @@
+#ifndef _MINIX_BTRACE_H
+#define _MINIX_BTRACE_H
+
+/* Control directives. */
+enum {
+  BTCTL_START,
+  BTCTL_STOP
+};
+
+/* Request codes. */
+enum {
+  BTREQ_OPEN,
+  BTREQ_CLOSE,
+  BTREQ_READ,
+  BTREQ_WRITE,
+  BTREQ_GATHER,
+  BTREQ_SCATTER,
+  BTREQ_IOCTL
+};
+
+/* Special result codes. */
+#define BTRES_INPROGRESS	(-997)
+
+/* Block trace entry. */
+typedef struct {
+  u32_t request;		/* request code; one of BTR_xxx */
+  u32_t size;			/* request size, ioctl request, or access */
+  u64_t position;		/* starting disk position */
+  u32_t flags;			/* transfer flags */
+  i32_t result;			/* request result; OK, bytes, or error */
+  u32_t start_time;		/* request service start time (us) */
+  u32_t finish_time;		/* request service completion time (us) */
+} btrace_entry;			/* (32 bytes) */
+
+/* This is the number of btrace_entry structures copied out at once using the
+ * BIOCTRACEGET ioctl call.
+ */
+#define BTBUF_SIZE	1024
+
+#endif /* _MINIX_BTRACE_H */

common/include/sys/Makefile.inc

@@ -3,7 +3,7 @@
 .PATH: ${MINIXSRCDIR}/common/include/sys
 
 INCS+= 	elf32.h elf64.h elf_common.h elf_generic.h \
-	ioc_file.h ioc_tape.h ioc_disk.h \
+	ioc_block.h ioc_file.h ioc_tape.h ioc_disk.h \
 	ioc_memory.h ioc_sound.h ioc_tty.h \
 	kbdio.h mtio.h svrctl.h video.h vm.h procfs.h elf_core.h exec_elf.h
 

common/include/sys/ioc_block.h

@@ -0,0 +1,15 @@
+/*	sys/ioc_block.h - Block ioctl() command codes.
+ *
+ */
+
+#ifndef _S_I_BLOCK_H
+#define _S_I_BLOCK_H
+
+#include <minix/ioctl.h>
+#include <minix/btrace.h>
+
+#define BIOCTRACEBUF	_IOW('b', 1, size_t)
+#define BIOCTRACECTL	_IOW('b', 2, int)
+#define BIOCTRACEGET	_IOR_BIG(3, btrace_entry[BTBUF_SIZE])
+
+#endif /* _S_I_BLOCK_H */