udev: add btrfs support

All "btrfs" file systems will be registered with the kernel when they
show up.

Incomplete multi-device volumes will set SYSTEMD_READY=0, to prevent
access until the volume is complete and fully registered.

1 files changed, 57 insertions, 0 deletions

diff --git a/src/udev/udev-builtin-btrfs.c b/src/udev/udev-builtin-btrfs.c
new file mode 100644
index 0000000000..f95a75e393
--- /dev/null
+++ b/src/udev/udev-builtin-btrfs.c
@@ -0,0 +1,57 @@
+/*
+ * btrfs - volume management
+ *
+ * Copyright (C) 2012 Kay Sievers <kay@vrfy.org>
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ */
+
+#include <unistd.h>
+#include <stdlib.h>
+#include <string.h>
+#include <stdio.h>
+#include <fcntl.h>
+#include <errno.h>
+#include <sys/ioctl.h>
+
+#include "udev.h"
+
+#define BTRFS_PATH_NAME_MAX 4087
+struct btrfs_ioctl_vol_args {
+        int64_t fd;
+        char name[BTRFS_PATH_NAME_MAX + 1];
+};
+#define BTRFS_IOCTL_MAGIC 0x94
+#define BTRFS_IOC_DEVICES_READY _IOR(BTRFS_IOCTL_MAGIC, 39, struct btrfs_ioctl_vol_args)
+
+static int builtin_btrfs(struct udev_device *dev, int argc, char *argv[], bool test)
+{
+        struct  btrfs_ioctl_vol_args args;
+        int fd;
+        int err;
+
+        if (argc != 3 || !streq(argv[1], "ready"))
+                return EXIT_FAILURE;
+
+        fd = open("/dev/btrfs-control", O_RDWR);
+        if (fd < 0)
+                return EXIT_FAILURE;
+
+        util_strscpy(args.name, sizeof(args.name), argv[2]);
+        err = ioctl(fd, BTRFS_IOC_DEVICES_READY, &args);
+        close(fd);
+        if (err < 0)
+                return EXIT_FAILURE;
+
+        udev_builtin_add_property(dev, test, "ID_BTRFS_READY", err == 0 ? "1" : "0");
+        return EXIT_SUCCESS;
+}
+
+const struct udev_builtin udev_builtin_btrfs = {
+        .name = "btrfs",
+        .cmd = builtin_btrfs,
+        .help = "btrfs volume management",
+};