From ebiederm@xmission.com Fri Jul 20 23:21:06 2007 From: ebiederm@xmission.com (Eric W. Biederman) Date: Wed, 18 Jul 2007 22:46:39 -0600 Subject: [PATCH 3/4] sysfs: Implement sysfs_delete_link and sysfs_rename_link To: Greg KH Cc: Greg KH , Dave Hansen , Benjamin Thery , Linux Containers , Tejun Heo Message-ID: When removing a symlink sysfs_remove_link does not provide enough information to figure out which shadow directory the symlink falls in. So I need sysfs_delete_link which is passed the target of the symlink to delete. Further half the time when we are removing a symlink the code is actually renaming the symlink but not doing so explicitly because we don't have a symlink rename method. So I have added sysfs_rename_link as well. Both of these functions now have enough information to find a symlink in a shadow directory. The only restriction is that they must be called before the target kobject is renamed or deleted. If they are called later I loose track of which tag the target kobject was marked with and can no longer find the old symlink to remove it. Signed-off-by: Eric W. Biederman Cc: Tejun Heo Signed-off-by: Greg Kroah-Hartman --- fs/sysfs/symlink.c | 31 +++++++++++++++++++++++++++++++ include/linux/sysfs.h | 18 ++++++++++++++++++ 2 files changed, 49 insertions(+) --- a/fs/sysfs/symlink.c +++ b/fs/sysfs/symlink.c @@ -126,6 +126,21 @@ addrm_finish: /** + * sysfs_delete_link - remove symlink in object's directory. + * @kobj: object we're acting for. + * @targ: object we're pointing to. + * @name: name of the symlink to remove. + * + * Unlike sysfs_remove_link sysfs_delete_link has enough information + * to successfully delete symlinks in shadow directories. + */ +void sysfs_delete_link(struct kobject *kobj, struct kobject *targ, + const char *name) +{ + sysfs_hash_and_remove(targ, kobj->sd, name); +} + +/** * sysfs_remove_link - remove symlink in object's directory. * @kobj: object we're acting for. * @name: name of the symlink to remove. @@ -136,6 +151,22 @@ void sysfs_remove_link(struct kobject * sysfs_hash_and_remove(kobj, kobj->sd, name); } +/** + * sysfs_rename_link - rename symlink in object's directory. + * @kobj: object we're acting for. + * @targ: object we're pointing to. + * @old: previous name of the symlink. + * @new: new name of the symlink. + * + * A helper function for the common rename symlink idiom. + */ +int sysfs_rename_link(struct kobject *kobj, struct kobject *targ, + const char *old, const char *new) +{ + sysfs_delete_link(kobj, targ, old); + return sysfs_create_link(kobj, targ, new); +} + static int sysfs_get_target_path(struct sysfs_dirent * parent_sd, struct sysfs_dirent * target_sd, char *path) { --- a/include/linux/sysfs.h +++ b/include/linux/sysfs.h @@ -127,6 +127,13 @@ sysfs_create_link(struct kobject * kobj, extern void sysfs_remove_link(struct kobject *, const char * name); +extern int +sysfs_rename_link(struct kobject *kobj, struct kobject *target, + const char *old_name, const char *new_name); + +extern void +sysfs_delete_link(struct kobject *dir, struct kobject *targ, const char *name); + int __must_check sysfs_create_bin_file(struct kobject *kobj, struct bin_attribute *attr); void sysfs_remove_bin_file(struct kobject *kobj, struct bin_attribute *attr); @@ -202,6 +209,17 @@ static inline void sysfs_remove_link(str ; } +static inline int +sysfs_rename_link(struct kobject * k, struct kobject *t, + const char *old_name, const char * new_name) +{ + return 0; +} + +static inline void +sysfs_delete_link(struct kobject *k, struct kobject *t, const char *name) +{ +} static inline int sysfs_create_bin_file(struct kobject * k, struct bin_attribute * a) {