cmd_reset_counters

Add a subcommand for resetting superblock counters - for automated tests

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

bcachefs.c

@@ -34,6 +34,7 @@ static void usage(void)
 	     "  format                   Format a new filesystem\n"
 	     "  show-super               Dump superblock information to stdout\n"
 	     "  set-option               Set a filesystem option\n"
+	     "  reset-counters           Reset all counters on an unmounted device\n"
 	     "\n"
 #ifndef BCACHEFS_NO_RUST
 	     "Mount:\n"
@@ -236,6 +237,8 @@ int main(int argc, char *argv[])
 		return cmd_show_super(argc, argv);
 	if (!strcmp(cmd, "set-option"))
 		return cmd_set_option(argc, argv);
+	if (!strcmp(cmd, "reset-counters"))
+		return cmd_reset_counters(argc, argv);
 
 #if 0
 	if (!strcmp(cmd, "assemble"))

cmd_counters.c

@@ -0,0 +1,51 @@
+#include <getopt.h>
+
+#include "cmds.h"
+#include "libbcachefs.h"
+#include "libbcachefs/super-io.h"
+
+static void reset_counters_usage(void)
+{
+	puts("bcachefs reset-counters \n"
+	     "Usage: bcachefs reset-counters device\n"
+	     "\n"
+	     "Options:\n"
+	     "  -h, --help                  display this help and exit\n"
+	     "Report bugs to <linux-bcachefs@vger.kernel.org>");
+	exit(EXIT_SUCCESS);
+}
+
+int cmd_reset_counters(int argc, char *argv[])
+{
+	static const struct option longopts[] = {
+		{ "help",			0, NULL, 'h' },
+		{ NULL }
+	};
+	int opt;
+
+	while ((opt = getopt_long(argc, argv, "h", longopts, NULL)) != -1)
+		switch (opt) {
+		case 'h':
+			reset_counters_usage();
+			break;
+		}
+	args_shift(optind);
+
+	char *dev = arg_pop();
+	if (!dev)
+		die("please supply a device");
+	if (argc)
+		die("too many arguments");
+
+	struct bch_opts opts = bch2_opts_empty();
+	struct bch_sb_handle sb;
+	int ret = bch2_read_super(dev, &opts, &sb);
+	if (ret)
+		die("Error opening %s: %s", dev, bch2_err_str(ret));
+
+	bch2_sb_field_resize(&sb, counters, 0);
+
+	bch2_super_write(sb.bdev->bd_buffered_fd, sb.sb);
+	bch2_free_super(&sb);
+	return 0;
+}

cmds.h

@@ -11,6 +11,7 @@
 
 int cmd_format(int argc, char *argv[]);
 int cmd_show_super(int argc, char *argv[]);
+int cmd_reset_counters(int argc, char *argv[]);
 int cmd_set_option(int argc, char *argv[]);
 
 int cmd_fs_usage(int argc, char *argv[]);