A little gadget to dump the contents of the vfs name cache.

3 files changed, 137 insertions, 0 deletions

diff --git a/tools/diag/dumpvfscache/Makefile b/tools/diag/dumpvfscache/Makefile
new file mode 100644
index 0000000..a9299ce
--- /dev/null
+++ b/tools/diag/dumpvfscache/Makefile
@@ -0,0 +1,11 @@
+
+PROG=	dumpvfscache
+
+LDADD=	-lkvm -lmd
+
+NOMAN=	1
+
+test:	${PROG}
+	./${PROG} > a
+
+.include <bsd.prog.mk>
diff --git a/tools/diag/dumpvfscache/README b/tools/diag/dumpvfscache/README
new file mode 100644
index 0000000..2a1c57c
--- /dev/null
+++ b/tools/diag/dumpvfscache/README
@@ -0,0 +1,6 @@
+This is a little C-program that can be used to examine the contents of
+the vfs name cache.  It's very likely to loop and crash if you use it
+on an active system.
+
+					Poul-Henning Kamp
+					4 sep 1997
diff --git a/tools/diag/dumpvfscache/dumpvfscache.c b/tools/diag/dumpvfscache/dumpvfscache.c
new file mode 100644
index 0000000..6deaab6
--- /dev/null
+++ b/tools/diag/dumpvfscache/dumpvfscache.c
@@ -0,0 +1,120 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <kvm.h>
+#include <nlist.h>
+#include <sys/uio.h>
+#include <sys/namei.h>
+#include <sys/param.h>
+#include <sys/time.h>
+#include <sys/vnode.h>
+/*----------------------------------*/
+static u_int crc16_table[16] = { 
+    0x0000, 0xCC01, 0xD801, 0x1400,
+    0xF001, 0x3C00, 0x2800, 0xE401,
+    0xA001, 0x6C00, 0x7800, 0xB401,
+    0x5000, 0x9C01, 0x8801, 0x4400 
+};
+
+static u_short
+wlpsacrc(u_char *buf, u_int len)
+{
+    u_short     crc = 0;
+    int         i, r1;
+    
+    for (i = 0; i < len; i++, buf++) {
+        /* lower 4 bits */
+        r1 = crc16_table[crc & 0xF];
+        crc = (crc >> 4) & 0x0FFF;
+        crc = crc ^ r1 ^ crc16_table[*buf & 0xF];
+        
+        /* upper 4 bits */
+        r1 = crc16_table[crc & 0xF];
+        crc = (crc >> 4) & 0x0FFF;
+        crc = crc ^ r1 ^ crc16_table[(*buf >> 4) & 0xF];
+    }
+    return(crc);
+}
+
+/*----------------------------------*/
+struct nlist nl[] = {
+	{ "_nchash", 0},
+	{ "_nchashtbl", 0},
+	{ 0, 0 },
+};
+
+int histo[2047];
+int histn[2047];
+int *newbucket;
+
+int
+main(int argc, char **argv)
+{
+	int nchash, i, j, k, kn;
+	int nb, p1, p2;
+	u_long p;
+	LIST_HEAD(nchashhead, namecache) *nchashtbl;
+	struct namecache *nc;
+	struct vnode vn;
+
+	kvm_t *kvm = kvm_open(0, 0, 0, O_RDONLY, 0);
+
+	printf("kvm: %p\n", kvm);
+	printf("kvm_nlist: %d\n", kvm_nlist(kvm, nl));
+	kvm_read(kvm, nl[0].n_value, &nchash, sizeof nchash);
+	nchash++;
+	nchashtbl = malloc(nchash * sizeof *nchashtbl);
+	nc = malloc(sizeof *nc + 400);
+	newbucket = malloc(nchash * sizeof (int));
+	memset(newbucket, 0, nchash * sizeof (int));
+	kvm_read(kvm, nl[1].n_value, &p, sizeof p);
+	kvm_read(kvm, p, nchashtbl, nchash * sizeof *nchashtbl);
+	for (i=0; i < nchash; i++) {
+#if 0
+		printf("%d\n", i);
+#endif
+		nb=0;
+		p = (u_long)LIST_FIRST(nchashtbl+i);
+		while (p) {
+			nb++;
+			kvm_read(kvm, p, nc, sizeof *nc + 400);
+			kvm_read(kvm, (u_long)nc->nc_dvp, &vn, sizeof vn);
+			nc->nc_name[nc->nc_nlen] = '\0';
+			for (j=k=kn=0;nc->nc_name[j];j++) {
+				k+= nc->nc_name[j];
+				kn <<= 1;
+				kn+= nc->nc_name[j];
+			}
+			/*
+			kn = k;
+			*/
+			kn = wlpsacrc(nc->nc_name,nc->nc_nlen);
+
+			/* kn += (u_long)vn.v_data >> 8;  */
+			/* kn += (u_long)nc->nc_dvp >> 7;    */
+			kn += vn.v_id; 
+			kn &= (nchash - 1);
+			newbucket[kn]++;
+#if 1
+			printf("%4d  dvp %08x  hash %08x  vp %08x  id %08x  name <%s>\n",
+				i,nc->nc_dvp, k, nc->nc_vp, vn.v_id, nc->nc_name);
+#endif
+			p = (u_long)LIST_NEXT(nc, nc_hash);
+		}
+		histo[nb]++;
+	}
+	for (i=0; i < nchash; i++) {
+		histn[newbucket[i]]++;
+	}
+	p1=p2 = 0;
+	for (i=0;i<30;i++) {
+		p1 += histo[i] * i;
+		p2 += histn[i] * i;
+		if (histo[i] || histn[i])
+			printf("H%02d %4d %4d / %4d %4d\n",i,histo[i], p1 , histn[i], p2);
+	}
+		
+	return (0);
+}
+