4 files changed, 57 insertions, 0 deletions

diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index 498452ebfd37..c5c888fbf033 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -3780,6 +3780,8 @@ int btrfs_defrag_leaves(struct btrfs_trans_handle *trans,
 /* sysfs.c */
 int btrfs_init_sysfs(void);
 void btrfs_exit_sysfs(void);
+int btrfs_sysfs_add_one(struct btrfs_fs_info *fs_info);
+void btrfs_sysfs_remove_one(struct btrfs_fs_info *fs_info);
 
 /* xattr.c */
 ssize_t btrfs_listxattr(struct dentry *dentry, char *buffer, size_t size);
diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index 435ef132b800..81f3433fe4fd 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -48,6 +48,7 @@
 #include "rcu-string.h"
 #include "dev-replace.h"
 #include "raid56.h"
+#include "sysfs.h"
 
 #ifdef CONFIG_X86
 #include <asm/cpufeature.h>
@@ -2743,6 +2744,12 @@ retry_root_backup:
 
         btrfs_close_extra_devices(fs_info, fs_devices, 1);
 
+        ret = btrfs_sysfs_add_one(fs_info);
+        if (ret) {
+                pr_err("btrfs: failed to init sysfs interface: %d\n", ret);
+                goto fail_block_groups;
+        }
+
         ret = btrfs_init_space_info(fs_info);
         if (ret) {
                 printk(KERN_ERR "Failed to initial space info: %d\n", ret);
@@ -3584,6 +3591,8 @@ int close_ctree(struct btrfs_root *root)
                        percpu_counter_sum(&fs_info->delalloc_bytes));
         }
 
+        btrfs_sysfs_remove_one(fs_info);
+
         del_fs_roots(fs_info);
 
         btrfs_free_block_groups(fs_info);
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;
diff --git a/fs/btrfs/sysfs.h b/fs/btrfs/sysfs.h
index 863e031ed1c1..d7c61bdf04ba 100644
--- a/fs/btrfs/sysfs.h
+++ b/fs/btrfs/sysfs.h
@@ -15,6 +15,13 @@ enum btrfs_feature_set {
         .store  = _store,                                               \
 }
 
+#define BTRFS_ATTR_RW(_name, _mode, _show, _store)                      \
+static struct kobj_attribute btrfs_attr_##_name =                       \
+                        __INIT_KOBJ_ATTR(_name, _mode, _show, _store)
+#define BTRFS_ATTR(_name, _mode, _show)                                 \
+        BTRFS_ATTR_RW(_name, _mode, _show, NULL)
+#define BTRFS_ATTR_PTR(_name)    (&btrfs_attr_##_name.attr)
+
 struct btrfs_feature_attr {
         struct kobj_attribute kobj_attr;
         enum btrfs_feature_set feature_set;
@@ -40,4 +47,7 @@ static struct btrfs_feature_attr btrfs_attr_##_name = {			     \
 /* convert from attribute */
 #define to_btrfs_feature_attr(a) \
                         container_of(a, struct btrfs_feature_attr, kobj_attr)
+#define attr_to_btrfs_attr(a) container_of(a, struct kobj_attribute, attr)
+#define attr_to_btrfs_feature_attr(a) \
+                        to_btrfs_feature_attr(attr_to_btrfs_attr(a))
 #endif /* _BTRFS_SYSFS_H_ */