debugfs.ocfs2: net_stats reads user specified file

Patch adds -f option to the net_stats command to allow the user to specify
a file that is a saved copy of /sys/kernel/debug/o2net/stats.

Signed-off-by: Sunil Mushran <sunil.mushran@oracle.com>

Author: Sunil Mushran

debugfs.ocfs2/commands.c

@@ -230,7 +230,7 @@ static struct command commands[] = {
 	},
 	{ "net_stats",
 		do_net_stats,
-		"net_stats [interval [count]]",
+		"net_stats [-f <file>] [interval [count]]",
 		"Show net statistics",
 	},
 	{ "ncheck",
@@ -2189,20 +2189,39 @@ static void do_refcount(char **args)
 static void do_net_stats(char **args)
 {
 	int interval = 0, count = 0;
-	char *net_stats_usage = "usage: net_stats [interval [count]]";
+	char *net_stats_usage = "usage: net_stats [-f <file>] [interval [count]]";
 	char *endptr;
+	char *path = NULL;
+	int c, argc;
+
+	for (argc = 0; (args[argc]); ++argc);
+	optind = 0;
 
-	if (args[1]) {
-		interval = strtoul(args[1], &endptr, 0);
-		if (!*endptr && args[2])
-			count = strtoul(args[2], &endptr, 0);
+	while ((c = getopt(argc, args, "f:")) != -1) {
+		switch (c) {
+		case 'f':
+			path = optarg;
+			break;
+		default:
+			break;
+		}
+	}
+
+	if (args[optind]) {
+		interval = strtoul(args[optind], &endptr, 0);
+		if (!*endptr && args[++optind])
+			count = strtoul(args[optind], &endptr, 0);
 		if (*endptr) {
 			fprintf(stderr, "%s\n", net_stats_usage);
 			return ;
 		}
 	}
 
-	dump_net_stats(stdout, interval, count);
+	/* Ignore device is user specifies the stats file */
+	if (path == NULL && check_device_open())
+		return;
+
+	dump_net_stats(stdout, path, interval, count);
 }
 
 static void do_stat_sysdir(char **args)

debugfs.ocfs2/debugfs.ocfs2.8.in

@@ -229,8 +229,10 @@ Print the listing  of the files in the directory \fIfilespec\fR. The
 \fI\-l\fR flag will list files in the long format.
 
 .TP
-\fInet_stats [interval [count]]\fR
-Display net statistics.
+\fInet_stats [-f <file>] [interval [count]]\fR
+Display the net statistics. This command expects the debugfs filesystem to be
+mounted at \fI/sys/kernel/debug\fR. The \fIinterval\fR is in seconds. Use the
+\fI-f\fR parameter to specify a saved copy of /sys/kernel/debug/o2net/stats.
 
 .TP
 \fIncheck [<lockname>|<inode#>] ...\fR

debugfs.ocfs2/dump_net_stats.c

@@ -119,8 +119,9 @@ static void show_net_stats(FILE *out, struct net_stats *prev,
 #define CURRENT_O2NET_STATS_PROTO	1
 #define MAX_O2NET_STATS_STR_LEN		1024
 
-static int read_net_stats(const char *debugfs_path, struct net_stats *stats,
-			    int num_entries, unsigned long *proto)
+static int read_net_stats(const char *debugfs_path, char *path,
+			  struct net_stats *stats, int num_entries,
+			  unsigned long *proto)
 {
 	FILE *file = NULL;
 	char rec1[MAX_O2NET_STATS_STR_LEN], rec2[MAX_O2NET_STATS_STR_LEN];
@@ -129,11 +130,21 @@ static int read_net_stats(const char *debugfs_path, struct net_stats *stats,
 
 	memset(stats, 0, sizeof(struct net_stats) * num_entries);
 
-	ret = open_debugfs_file(debugfs_path, "o2net", NULL, "stats", &file);
-	if (ret) {
-		com_err(cmd, ret, "Could not open %s/o2net/stats\n",
-			debugfs_path);
-		goto bail;
+	if (!path) {
+		ret = open_debugfs_file(debugfs_path, "o2net", NULL, "stats",
+					&file);
+		if (ret) {
+			com_err(cmd, ret, "; could not open %s/o2net/stats",
+				debugfs_path);
+			goto bail;
+		}
+	} else {
+		file = fopen(path, "r");
+		if (!file) {
+			ret = errno;
+			com_err(cmd, ret, "\"%s\"", path);
+			goto bail;
+		}
 	}
 
 	while (fgets(rec1, sizeof(rec1), file)) {
@@ -196,7 +207,7 @@ static int read_net_stats(const char *debugfs_path, struct net_stats *stats,
 	return ret;
 }
 
-void dump_net_stats(FILE *out, int interval, int count)
+void dump_net_stats(FILE *out, char *path, int interval, int count)
 {
 	errcode_t ret;
 	char debugfs_path[PATH_MAX];
@@ -216,7 +227,8 @@ void dump_net_stats(FILE *out, int interval, int count)
 	memset(prev, 0 , sizeof(buf1));
 
 	do {
-		ret = read_net_stats(debugfs_path, curr, O2NM_MAX_NODES, &proto);
+		ret = read_net_stats(debugfs_path, path, curr, O2NM_MAX_NODES,
+				     &proto);
 		if (ret)
 			break;
 

debugfs.ocfs2/include/dump_net_stats.h

@@ -35,6 +35,6 @@ struct net_stats {
 	long long ns_proc_time;
 };
 
-void dump_net_stats(FILE *out, int interval, int count);
+void dump_net_stats(FILE *out, char *path, int interval, int count);
 
 #endif		/* _DUMP_NET_STATS_H_ */