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.

Makefile.am

@@ -1737,6 +1737,7 @@ dist_udevrules_DATA += \
 	rules/60-persistent-input.rules \
 	rules/60-persistent-alsa.rules \
 	rules/60-persistent-storage.rules \
+	rules/64-btrfs.rules \
 	rules/75-net-description.rules \
 	rules/75-tty-description.rules \
 	rules/78-sound-card.rules \
@@ -1797,6 +1798,7 @@ libudev_core_la_SOURCES = \
 	src/udev/udev-ctrl.c \
 	src/udev/udev-builtin.c \
 	src/udev/udev-builtin-blkid.c \
+	src/udev/udev-builtin-btrfs.c \
 	src/udev/udev-builtin-firmware.c \
 	src/udev/udev-builtin-hwdb.c \
 	src/udev/udev-builtin-input_id.c \

rules/64-btrfs.rules

@@ -0,0 +1,13 @@
+# do not edit this file, it will be overwritten on update
+
+SUBSYSTEM!="block", GOTO="btrfs_end"
+ACTION=="remove", GOTO="btrfs_end"
+ENV{ID_FS_TYPE}!="btrfs", GOTO="btrfs_end"
+
+# let the kernel know about this btrfs filesystem, and check if it is complete
+IMPORT{builtin}="btrfs ready $devnode"
+
+# mark the device as not ready to be used by the system
+ENV{ID_BTRFS_READY}=="0", ENV{SYSTEMD_READY}="0"
+
+LABEL="btrfs_end"

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",
+};

src/udev/udev-builtin.c

@@ -29,6 +29,7 @@ static bool initialized;
 
 static const struct udev_builtin *builtins[] = {
         [UDEV_BUILTIN_BLKID] = &udev_builtin_blkid,
+        [UDEV_BUILTIN_BTRFS] = &udev_builtin_btrfs,
         [UDEV_BUILTIN_FIRMWARE] = &udev_builtin_firmware,
         [UDEV_BUILTIN_INPUT_ID] = &udev_builtin_input_id,
         [UDEV_BUILTIN_KMOD] = &udev_builtin_kmod,
@@ -142,7 +143,6 @@ int udev_builtin_add_property(struct udev_device *dev, bool test, const char *ke
         if (key[0] != '.')
                 udev_list_entry_set_num(entry, true);
 
-        log_debug("%s=%s\n", key, val);
         if (test)
                 printf("%s=%s\n", key, val);
         return 0;

src/udev/udev.h

@@ -135,6 +135,7 @@ int udev_ctrl_get_set_children_max(struct udev_ctrl_msg *ctrl_msg);
 /* built-in commands */
 enum udev_builtin_cmd {
         UDEV_BUILTIN_BLKID,
+        UDEV_BUILTIN_BTRFS,
         UDEV_BUILTIN_FIRMWARE,
         UDEV_BUILTIN_INPUT_ID,
         UDEV_BUILTIN_KMOD,
@@ -157,6 +158,7 @@ struct udev_builtin {
         bool run_once;
 };
 extern const struct udev_builtin udev_builtin_blkid;
+extern const struct udev_builtin udev_builtin_btrfs;
 extern const struct udev_builtin udev_builtin_firmware;
 extern const struct udev_builtin udev_builtin_input_id;
 extern const struct udev_builtin udev_builtin_kmod;

src/udev/udevadm-test-builtin.c

@@ -108,8 +108,9 @@ static int adm_builtin(struct udev *udev, int argc, char *argv[])
                 goto out;
         }
 
-        if (udev_builtin_run(dev, cmd, command, true) < 0) {
-                fprintf(stderr, "error executing '%s'\n\n", command);
+        rc = udev_builtin_run(dev, cmd, command, true);
+        if (rc < 0) {
+                fprintf(stderr, "error executing '%s', exit code %i\n\n", command, rc);
                 rc = 6;
         }
 out: