diff -u --recursive --new-file linux/drivers/block/ll_rw_blk.c linux-trace/drivers/block/ll_rw_blk.c
--- linux/drivers/block/ll_rw_blk.c	Fri Jun 29 21:58:07 2001
+++ linux-trace/drivers/block/ll_rw_blk.c	Tue Aug  7 18:23:36 2001
@@ -31,6 +31,33 @@
 
 #include <linux/module.h>
 
+#define N_PARAM 9
+
+/* stuff for I/O tracing (tell which process an I/O request came from) */
+union bdflush_param {
+	struct {
+		int nfract;  /* Percentage of buffer cache dirty to 
+				activate bdflush */
+		int ndirty;  /* Maximum number of dirty blocks to write out per
+				wake-cycle */
+		int nrefill; /* Number of clean buffers to try to obtain
+				each time we call refill */
+		int dummy1;   /* unused */
+		int interval; /* jiffies delay between kupdate flushes */
+		int age_buffer;  /* Time for normal buffer to age before we flush it */
+		int nfract_sync; /* Percentage of buffer cache dirty to 
+				    activate bdflush synchronously */
+		int dummy2;    /* unused */
+		int dummy3;    /* unused */
+	} b_un;
+	unsigned int data[N_PARAM];
+};
+
+extern union bdflush_param bdf_prm;
+
+#define io_tracing (bdf_prm.b_un.dummy2)
+/* end stuff for I/O tracing */
+
 /*
  * MAC Floppy IWM hooks
  */
@@ -525,6 +552,11 @@
 		return;
 
 	kstat.dk_drive[major][index] += new_io;
+
+	if (io_tracing) {
+	  printk("%s by %s\n", (rw==READ ? "read" : (rw==WRITE ? "write" : "??")), current->comm);
+	}
+
 	if (rw == READ) {
 		kstat.dk_drive_rio[major][index] += new_io;
 		kstat.dk_drive_rblk[major][index] += nr_sectors;
diff -u --recursive --new-file linux/fs/buffer.c linux-trace/fs/buffer.c
--- linux/fs/buffer.c	Sat Jun 30 13:44:32 2001
+++ linux-trace/fs/buffer.c	Tue Aug  7 17:42:26 2001
@@ -131,7 +131,7 @@
 
 /* These are the min and max parameter values that we will allow to be assigned */
 int bdflush_min[N_PARAM] = {  0,  10,    5,   25,  0,   1*HZ,   0, 0, 0};
-int bdflush_max[N_PARAM] = {100,50000, 20000, 20000,600*HZ, 6000*HZ, 100, 0, 0};
+int bdflush_max[N_PARAM] = {100,50000, 20000, 20000,600*HZ, 6000*HZ, 100, 1, 0};
 
 /*
  * Rewrote the wait-routines to use the "new" wait-queue functionality,