btrfs: publish per-super attributes in sysfs

This patch adds per-super attributes to sysfs.

It doesn't publish any attributes yet, but does the proper lifetime
handling as well as the basic infrastructure to add new attributes.

Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
Signed-off-by: Chris Mason <clm@fb.com>

1 files changed, 36 insertions, 0 deletions

diff --git a/fs/btrfs/sysfs.c b/fs/btrfs/sysfs.c
index 9e217b581903..79be4a187af9 100644
--- a/fs/btrfs/sysfs.c
+++ b/fs/btrfs/sysfs.c
@@ -28,6 +28,25 @@
 #include "transaction.h"
 #include "sysfs.h"
 
+static void btrfs_release_super_kobj(struct kobject *kobj);
+static struct kobj_type btrfs_ktype = {
+        .sysfs_ops      = &kobj_sysfs_ops,
+        .release        = btrfs_release_super_kobj,
+};
+
+static inline struct btrfs_fs_info *to_fs_info(struct kobject *kobj)
+{
+        if (kobj->ktype != &btrfs_ktype)
+                return NULL;
+        return container_of(kobj, struct btrfs_fs_info, super_kobj);
+}
+
+static void btrfs_release_super_kobj(struct kobject *kobj)
+{
+        struct btrfs_fs_info *fs_info = to_fs_info(kobj);
+        complete(&fs_info->kobj_unregister);
+}
+
 static ssize_t btrfs_feature_attr_show(struct kobject *kobj,
                                        struct kobj_attribute *a, char *buf)
 {
@@ -65,6 +84,23 @@ static const struct attribute_group btrfs_feature_attr_group = {
 /* /sys/fs/btrfs/ entry */
 static struct kset *btrfs_kset;
 
+void btrfs_sysfs_remove_one(struct btrfs_fs_info *fs_info)
+{
+        kobject_del(&fs_info->super_kobj);
+        kobject_put(&fs_info->super_kobj);
+        wait_for_completion(&fs_info->kobj_unregister);
+}
+
+int btrfs_sysfs_add_one(struct btrfs_fs_info *fs_info)
+{
+        int error;
+
+        init_completion(&fs_info->kobj_unregister);
+        error = kobject_init_and_add(&fs_info->super_kobj, &btrfs_ktype, NULL,
+                                     "%pU", fs_info->fsid);
+        return error;
+}
+
 int btrfs_init_sysfs(void)
 {
         int ret;