cmd_show_super: Also print device model

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

c_src/cmd_format.c

@@ -384,6 +384,15 @@ int cmd_show_super(int argc, char *argv[])
 		if (f)
 			__bch2_sb_field_to_text(&buf, sb.sb, f);
 	} else {
+		printbuf_tabstop_push(&buf, 44);
+
+		char *model = fd_to_dev_model(sb.bdev->bd_fd);
+		prt_str(&buf, "Device:");
+		prt_tab(&buf);
+		prt_str(&buf, model);
+		prt_newline(&buf);
+		free(model);
+
 		bch2_sb_to_text(&buf, sb.sb, print_layout, fields);
 	}
 	printf("%s", buf.buf);

c_src/tools-util.c

@@ -579,6 +579,49 @@ int dev_mounted(char *dev)
 	return 2;
 }
 
+static char *dev_to_sysfs_path(dev_t dev)
+{
+	return mprintf("/sys/dev/block/%u:%u", major(dev), minor(dev));
+}
+
+char *fd_to_dev_model(int fd)
+{
+	struct stat stat = xfstat(fd);
+
+	if (S_ISBLK(stat.st_mode)) {
+		char *sysfs_path = dev_to_sysfs_path(stat.st_rdev);
+
+		char *model_path = mprintf("%s/device/model", sysfs_path);
+		if (!access(model_path, R_OK))
+			goto got_model;
+		free(model_path);
+
+		/* partition? try parent */
+
+		char buf[1024];
+		if (readlink(sysfs_path, buf, sizeof(buf)) < 0)
+			die("readlink error on %s: %m", sysfs_path);
+
+		free(sysfs_path);
+		sysfs_path = strdup(buf);
+
+		*strrchr(sysfs_path, '/') = 0;
+		model_path = mprintf("%s/device/model", sysfs_path);
+		if (!access(model_path, R_OK))
+			goto got_model;
+
+		return strdup("(unknown device)");
+		char *model;
+got_model:
+		model = read_file_str(AT_FDCWD, model_path);
+		free(model_path);
+		free(sysfs_path);
+		return model;
+	} else {
+		return strdup("(reg file)");
+	}
+}
+
 static int kstrtoull_symbolic(const char *s, unsigned int base, unsigned long long *res)
 {
 	if (!strcmp(s, "U64_MAX")) {

c_src/tools-util.h

@@ -180,6 +180,7 @@ char *dev_to_name(dev_t);
 char *dev_to_path(dev_t);
 struct mntent *dev_to_mount(char *);
 int dev_mounted(char *);
+char *fd_to_dev_model(int);
 
 #define args_shift(_nr)							\
 do {									\