When creating a new per-namespace filesystem static initialisation doesn't work, so implement a 'fill_subsystem' and 'clear_subsystem' callbacks to 'struct configfs_subsystem' to allow for every driver to populate the subsystem structure dynamicall. Signed-off-by: Hannes Reinecke --- fs/configfs/configfs_internal.h | 4 ++ fs/configfs/dir.c | 101 +++++++++++++++++++++++++++++++++++++++- fs/configfs/mount.c | 4 ++ include/linux/configfs.h | 5 ++ 4 files changed, 113 insertions(+), 1 deletion(-) diff --git a/fs/configfs/configfs_internal.h b/fs/configfs/configfs_internal.h index a4f10dd8ce0f46873d2053860a9fd25f3ee4c809..35eddc274b88796442c080fe4fe8a6ea68762185 100644 --- a/fs/configfs/configfs_internal.h +++ b/fs/configfs/configfs_internal.h @@ -94,6 +94,10 @@ extern struct dentry *configfs_pin_fs(struct super_block *sb); extern void configfs_release_fs(struct super_block *sb); extern struct configfs_super_info *configfs_get_super_info(struct net *net_ns); extern void configfs_put_super_info(struct configfs_super_info *info); +extern void configfs_link_subsystems(struct super_block *sb, + struct configfs_super_info *info); +extern void configfs_unlink_subsystems(struct super_block *sb, + struct configfs_super_info *info); extern const struct file_operations configfs_dir_operations; extern const struct file_operations configfs_file_operations; diff --git a/fs/configfs/dir.c b/fs/configfs/dir.c index 9b3738f58ccb891a8269708f0e875b0a75c1ab8e..891238ef0088a98467d6d63a10d633a40fc19c8b 100644 --- a/fs/configfs/dir.c +++ b/fs/configfs/dir.c @@ -1931,15 +1931,92 @@ int configfs_register_subsystem(struct configfs_subsystem *subsys) goto out_put; } + if (subsys->fill_subsystem) { + INIT_LIST_HEAD(&subsys->su_link); + mutex_init(&subsys->su_mutex); + config_group_init(&subsys->su_group); + err = subsys->fill_subsystem(subsys, info->ns_id); + if (err) + goto out_release; + } + err = configfs_link_root(info, subsys, root); + if (err) { + if (subsys->clear_subsystem) + subsys->clear_subsystem(subsys, info->ns_id); + goto out_release; + } + + mutex_lock(&info->subsys_mutex); + list_add(&subsys->su_link, &info->subsys_list); + mutex_unlock(&info->subsys_mutex); + +out_release: if (err) configfs_release_fs(NULL); - out_put: configfs_put_super_info(info); return err; } +void configfs_link_subsystems(struct super_block *sb, + struct configfs_super_info *info) +{ + struct configfs_subsystem *s; + struct configfs_super_info *parent = configfs_get_super_info(0); + LIST_HEAD(subsys_list); + + if (WARN_ON(IS_ERR(parent))) + return; + if ((info->ns_id == 0) || WARN_ON(parent == info)) + return; + mutex_lock(&parent->subsys_mutex); + list_splice_init(&parent->subsys_list, &subsys_list); + mutex_unlock(&parent->subsys_mutex); + list_for_each_entry(s, &subsys_list, su_link) { + struct configfs_subsystem *subsys; + struct dentry *root; + int err; + + if (!s->fill_subsystem) + continue; + subsys = kzalloc_obj(*subsys); + if (!subsys) + continue; + subsys->fill_subsystem = s->fill_subsystem; + subsys->clear_subsystem = s->clear_subsystem; + INIT_LIST_HEAD(&subsys->su_link); + mutex_init(&subsys->su_mutex); + err = subsys->fill_subsystem(subsys, info->ns_id); + if (err) { + kfree(subsys); + continue; + } + root = configfs_pin_fs(sb); + if (IS_ERR(root)) { + if (subsys->clear_subsystem) + subsys->clear_subsystem(subsys, info->ns_id); + kfree(subsys); + continue; + } + err = configfs_link_root(info, subsys, root); + if (err) { + configfs_release_fs(sb); + if (subsys->clear_subsystem) + subsys->clear_subsystem(subsys, info->ns_id); + kfree(subsys); + continue; + } + mutex_lock(&info->subsys_mutex); + list_add(&subsys->su_link, &info->subsys_list); + mutex_unlock(&info->subsys_mutex); + } + mutex_lock(&parent->subsys_mutex); + list_splice(&subsys_list, &parent->subsys_list); + mutex_unlock(&parent->subsys_mutex); + configfs_put_super_info(parent); +} + static bool configfs_unlink_root(struct configfs_subsystem *subsys) { struct config_group *group = &subsys->su_group; @@ -1982,6 +2059,25 @@ static bool configfs_unlink_root(struct configfs_subsystem *subsys) return true; } +void configfs_unlink_subsystems(struct super_block *sb, + struct configfs_super_info *info) +{ + struct configfs_subsystem *subsys, *s; + + mutex_lock(&info->subsys_mutex); + list_for_each_entry_safe(subsys, s, &info->subsys_list, su_link) { + list_del_init(&subsys->su_link); + if (!configfs_unlink_root(subsys)) + continue; + if (subsys->clear_subsystem) + subsys->clear_subsystem(subsys, info->ns_id); + unlink_group(&subsys->su_group); + configfs_release_fs(sb); + kfree(subsys); + } + mutex_unlock(&info->subsys_mutex); +} + void configfs_unregister_subsystem(struct configfs_subsystem *subsys) { struct configfs_super_info *info = configfs_get_super_info(0); @@ -1994,6 +2090,9 @@ void configfs_unregister_subsystem(struct configfs_subsystem *subsys) return; mutex_lock(&info->subsys_mutex); + list_del_init(&subsys->su_link); + if (subsys->clear_subsystem) + subsys->clear_subsystem(subsys, info->ns_id); unlink_group(group); mutex_unlock(&info->subsys_mutex); configfs_release_fs(NULL); diff --git a/fs/configfs/mount.c b/fs/configfs/mount.c index 8b26ceb7b0d4a03a17c251de42902aaabef5a652..d36fc4a6f6439bea645e62b8423b518a5d7d51c1 100644 --- a/fs/configfs/mount.c +++ b/fs/configfs/mount.c @@ -157,6 +157,9 @@ static int configfs_fill_super(struct super_block *sb, struct fs_context *fc) sb->s_root = root; set_default_d_op(sb, &configfs_dentry_ops); /* the rest get that */ sb->s_d_flags |= DCACHE_DONTCACHE; + + configfs_link_subsystems(sb, info); + return 0; } @@ -179,6 +182,7 @@ static void configfs_kill_sb(struct super_block *sb) { struct configfs_super_info *info = sb->s_fs_info; + configfs_unlink_subsystems(sb, info); kill_anon_super(sb); configfs_put_super_info(info); sb->s_fs_info = NULL; diff --git a/include/linux/configfs.h b/include/linux/configfs.h index 19165e36da810c75500bb584702ae3a594c3510d..c1cdadba0a48f0abea30da5ee324807b9ac4ff8f 100644 --- a/include/linux/configfs.h +++ b/include/linux/configfs.h @@ -227,8 +227,13 @@ struct configfs_group_operations { }; struct configfs_subsystem { + struct list_head su_link; struct config_group su_group; struct mutex su_mutex; + int (*fill_subsystem)(struct configfs_subsystem *subsys, + u64 ns_id); + void (*clear_subsystem)(struct configfs_subsystem *subsys, + u64 ns_id); }; static inline struct configfs_subsystem *to_configfs_subsystem(struct config_group *group) -- 2.51.0