[CFT][PATCH 08/10] sysfs: Add support for permanently empty directories to serve as mount points.
From: Eric W. Biederman <hidden>
Date: 2015-05-16 02:09:53
Add two functions sysfs_create_mount_point and sysfs_remove_mount_point that hang a permanently empty directory off of a kobject or remove a permanently emptpy directory hanging from a kobject. Export these new functions so modular filesystems can use them. Cc: stable-u79uwXL29TY76Z2rM5mHXA@public.gmane.org Signed-off-by: "Eric W. Biederman" <ebiederm-aS9lmoZGLiVWk0Htik3J/w@public.gmane.org> --- fs/sysfs/dir.c | 34 ++++++++++++++++++++++++++++++++++ include/linux/sysfs.h | 16 ++++++++++++++++ 2 files changed, 50 insertions(+)
diff --git a/fs/sysfs/dir.c b/fs/sysfs/dir.c
index 0b45ff42f374..94374e435025 100644
--- a/fs/sysfs/dir.c
+++ b/fs/sysfs/dir.c@@ -121,3 +121,37 @@ int sysfs_move_dir_ns(struct kobject *kobj, struct kobject *new_parent_kobj, return kernfs_rename_ns(kn, new_parent, kn->name, new_ns); } + +/** + * sysfs_create_mount_point - create an always empty directory + * @parent_kobj: kobject that will contain this always empty directory + * @name: The name of the always empty directory to add + */ +int sysfs_create_mount_point(struct kobject *parent_kobj, const char *name) +{ + struct kernfs_node *kn, *parent = parent_kobj->sd; + + kn = kernfs_create_empty_dir(parent, name); + if (IS_ERR(kn)) { + if (PTR_ERR(kn) == -EEXIST) + sysfs_warn_dup(parent, name); + return PTR_ERR(kn); + } + + return 0; +} +EXPORT_SYMBOL_GPL(sysfs_create_mount_point); + +/** + * sysfs_remove_mount_point - remove an always empty directory. + * @parent_kobj: kobject that will contain this always empty directory + * @name: The name of the always empty directory to remove + * + */ +void sysfs_remove_mount_point(struct kobject *parent_kobj, const char *name) +{ + struct kernfs_node *parent = parent_kobj->sd; + + kernfs_remove_by_name_ns(parent, name, NULL); +} +EXPORT_SYMBOL_GPL(sysfs_remove_mount_point);
diff --git a/include/linux/sysfs.h b/include/linux/sysfs.h
index 99382c0df17e..3e7e41acc451 100644
--- a/include/linux/sysfs.h
+++ b/include/linux/sysfs.h@@ -210,6 +210,10 @@ int __must_check sysfs_rename_dir_ns(struct kobject *kobj, const char *new_name, int __must_check sysfs_move_dir_ns(struct kobject *kobj, struct kobject *new_parent_kobj, const void *new_ns); +int __must_check sysfs_create_mount_point(struct kobject *parent_kobj, + const char *name); +void sysfs_remove_mount_point(struct kobject *parent_kobj, + const char *name); int __must_check sysfs_create_file_ns(struct kobject *kobj, const struct attribute *attr,
@@ -298,6 +302,18 @@ static inline int sysfs_move_dir_ns(struct kobject *kobj, return 0; } +static inline int sysfs_create_mount_point(struct kobject *parent_kobj, + const char *name) +{ + return 0; +} + +static inline void sysfs_remove_mount_point(struct kobject *parent_kobj, + const char *name) +{ + return 0; +} + static inline int sysfs_create_file_ns(struct kobject *kobj, const struct attribute *attr, const void *ns)
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2.2.1