diff options
Diffstat (limited to 'ANDROID_3.4.5/fs/configfs/dir.c')
| -rw-r--r-- | ANDROID_3.4.5/fs/configfs/dir.c | 1756 |
1 files changed, 0 insertions, 1756 deletions
diff --git a/ANDROID_3.4.5/fs/configfs/dir.c b/ANDROID_3.4.5/fs/configfs/dir.c deleted file mode 100644 index 7e6c52d8..00000000 --- a/ANDROID_3.4.5/fs/configfs/dir.c +++ /dev/null @@ -1,1756 +0,0 @@ -/* -*- mode: c; c-basic-offset: 8; -*- - * vim: noexpandtab sw=8 ts=8 sts=0: - * - * dir.c - Operations for configfs directories. - * - * This program is free software; you can redistribute it and/or - * modify it under the terms of the GNU General Public - * License as published by the Free Software Foundation; either - * version 2 of the License, or (at your option) any later version. - * - * This program is distributed in the hope that it will be useful, - * but WITHOUT ANY WARRANTY; without even the implied warranty of - * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU - * General Public License for more details. - * - * You should have received a copy of the GNU General Public - * License along with this program; if not, write to the - * Free Software Foundation, Inc., 59 Temple Place - Suite 330, - * Boston, MA 021110-1307, USA. - * - * Based on sysfs: - * sysfs is Copyright (C) 2001, 2002, 2003 Patrick Mochel - * - * configfs Copyright (C) 2005 Oracle. All rights reserved. - */ - -#undef DEBUG - -#include <linux/fs.h> -#include <linux/mount.h> -#include <linux/module.h> -#include <linux/slab.h> -#include <linux/err.h> - -#include <linux/configfs.h> -#include "configfs_internal.h" - -DECLARE_RWSEM(configfs_rename_sem); -/* - * Protects mutations of configfs_dirent linkage together with proper i_mutex - * Also protects mutations of symlinks linkage to target configfs_dirent - * Mutators of configfs_dirent linkage must *both* have the proper inode locked - * and configfs_dirent_lock locked, in that order. - * This allows one to safely traverse configfs_dirent trees and symlinks without - * having to lock inodes. - * - * Protects setting of CONFIGFS_USET_DROPPING: checking the flag - * unlocked is not reliable unless in detach_groups() called from - * rmdir()/unregister() and from configfs_attach_group() - */ -DEFINE_SPINLOCK(configfs_dirent_lock); - -static void configfs_d_iput(struct dentry * dentry, - struct inode * inode) -{ - struct configfs_dirent *sd = dentry->d_fsdata; - - if (sd) { - BUG_ON(sd->s_dentry != dentry); - /* Coordinate with configfs_readdir */ - spin_lock(&configfs_dirent_lock); - sd->s_dentry = NULL; - spin_unlock(&configfs_dirent_lock); - configfs_put(sd); - } - iput(inode); -} - -/* - * We _must_ delete our dentries on last dput, as the chain-to-parent - * behavior is required to clear the parents of default_groups. - */ -static int configfs_d_delete(const struct dentry *dentry) -{ - return 1; -} - -const struct dentry_operations configfs_dentry_ops = { - .d_iput = configfs_d_iput, - /* simple_delete_dentry() isn't exported */ - .d_delete = configfs_d_delete, -}; - -#ifdef CONFIG_LOCKDEP - -/* - * Helpers to make lockdep happy with our recursive locking of default groups' - * inodes (see configfs_attach_group() and configfs_detach_group()). - * We put default groups i_mutexes in separate classes according to their depth - * from the youngest non-default group ancestor. - * - * For a non-default group A having default groups A/B, A/C, and A/C/D, default - * groups A/B and A/C will have their inode's mutex in class - * default_group_class[0], and default group A/C/D will be in - * default_group_class[1]. - * - * The lock classes are declared and assigned in inode.c, according to the - * s_depth value. - * The s_depth value is initialized to -1, adjusted to >= 0 when attaching - * default groups, and reset to -1 when all default groups are attached. During - * attachment, if configfs_create() sees s_depth > 0, the lock class of the new - * inode's mutex is set to default_group_class[s_depth - 1]. - */ - -static void configfs_init_dirent_depth(struct configfs_dirent *sd) -{ - sd->s_depth = -1; -} - -static void configfs_set_dir_dirent_depth(struct configfs_dirent *parent_sd, - struct configfs_dirent *sd) -{ - int parent_depth = parent_sd->s_depth; - - if (parent_depth >= 0) - sd->s_depth = parent_depth + 1; -} - -static void -configfs_adjust_dir_dirent_depth_before_populate(struct configfs_dirent *sd) -{ - /* - * item's i_mutex class is already setup, so s_depth is now only - * used to set new sub-directories s_depth, which is always done - * with item's i_mutex locked. - */ - /* - * sd->s_depth == -1 iff we are a non default group. - * else (we are a default group) sd->s_depth > 0 (see - * create_dir()). - */ - if (sd->s_depth == -1) - /* - * We are a non default group and we are going to create - * default groups. - */ - sd->s_depth = 0; -} - -static void -configfs_adjust_dir_dirent_depth_after_populate(struct configfs_dirent *sd) -{ - /* We will not create default groups anymore. */ - sd->s_depth = -1; -} - -#else /* CONFIG_LOCKDEP */ - -static void configfs_init_dirent_depth(struct configfs_dirent *sd) -{ -} - -static void configfs_set_dir_dirent_depth(struct configfs_dirent *parent_sd, - struct configfs_dirent *sd) -{ -} - -static void -configfs_adjust_dir_dirent_depth_before_populate(struct configfs_dirent *sd) -{ -} - -static void -configfs_adjust_dir_dirent_depth_after_populate(struct configfs_dirent *sd) -{ -} - -#endif /* CONFIG_LOCKDEP */ - -/* - * Allocates a new configfs_dirent and links it to the parent configfs_dirent - */ -static struct configfs_dirent *configfs_new_dirent(struct configfs_dirent *parent_sd, - void *element, int type) -{ - struct configfs_dirent * sd; - - sd = kmem_cache_zalloc(configfs_dir_cachep, GFP_KERNEL); - if (!sd) - return ERR_PTR(-ENOMEM); - - atomic_set(&sd->s_count, 1); - INIT_LIST_HEAD(&sd->s_links); - INIT_LIST_HEAD(&sd->s_children); - sd->s_element = element; - sd->s_type = type; - configfs_init_dirent_depth(sd); - spin_lock(&configfs_dirent_lock); - if (parent_sd->s_type & CONFIGFS_USET_DROPPING) { - spin_unlock(&configfs_dirent_lock); - kmem_cache_free(configfs_dir_cachep, sd); - return ERR_PTR(-ENOENT); - } - list_add(&sd->s_sibling, &parent_sd->s_children); - spin_unlock(&configfs_dirent_lock); - - return sd; -} - -/* - * - * Return -EEXIST if there is already a configfs element with the same - * name for the same parent. - * - * called with parent inode's i_mutex held - */ -static int configfs_dirent_exists(struct configfs_dirent *parent_sd, - const unsigned char *new) -{ - struct configfs_dirent * sd; - - list_for_each_entry(sd, &parent_sd->s_children, s_sibling) { - if (sd->s_element) { - const unsigned char *existing = configfs_get_name(sd); - if (strcmp(existing, new)) - continue; - else - return -EEXIST; - } - } - - return 0; -} - - -int configfs_make_dirent(struct configfs_dirent * parent_sd, - struct dentry * dentry, void * element, - umode_t mode, int type) -{ - struct configfs_dirent * sd; - - sd = configfs_new_dirent(parent_sd, element, type); - if (IS_ERR(sd)) - return PTR_ERR(sd); - - sd->s_mode = mode; - sd->s_dentry = dentry; - if (dentry) - dentry->d_fsdata = configfs_get(sd); - - return 0; -} - -static int init_dir(struct inode * inode) -{ - inode->i_op = &configfs_dir_inode_operations; - inode->i_fop = &configfs_dir_operations; - - /* directory inodes start off with i_nlink == 2 (for "." entry) */ - inc_nlink(inode); - return 0; -} - -static int configfs_init_file(struct inode * inode) -{ - inode->i_size = PAGE_SIZE; - inode->i_fop = &configfs_file_operations; - return 0; -} - -static int init_symlink(struct inode * inode) -{ - inode->i_op = &configfs_symlink_inode_operations; - return 0; -} - -static int create_dir(struct config_item *k, struct dentry *d) -{ - int error; - umode_t mode = S_IFDIR| S_IRWXU | S_IRUGO | S_IXUGO; - struct dentry *p = d->d_parent; - - BUG_ON(!k); - - error = configfs_dirent_exists(p->d_fsdata, d->d_name.name); - if (!error) - error = configfs_make_dirent(p->d_fsdata, d, k, mode, - CONFIGFS_DIR | CONFIGFS_USET_CREATING); - if (!error) { - configfs_set_dir_dirent_depth(p->d_fsdata, d->d_fsdata); - error = configfs_create(d, mode, init_dir); - if (!error) { - inc_nlink(p->d_inode); - } else { - struct configfs_dirent *sd = d->d_fsdata; - if (sd) { - spin_lock(&configfs_dirent_lock); - list_del_init(&sd->s_sibling); - spin_unlock(&configfs_dirent_lock); - configfs_put(sd); - } - } - } - return error; -} - - -/** - * configfs_create_dir - create a directory for an config_item. - * @item: config_itemwe're creating directory for. - * @dentry: config_item's dentry. - * - * Note: user-created entries won't be allowed under this new directory - * until it is validated by configfs_dir_set_ready() - */ - -static int configfs_create_dir(struct config_item * item, struct dentry *dentry) -{ - int error = create_dir(item, dentry); - if (!error) - item->ci_dentry = dentry; - return error; -} - -/* - * Allow userspace to create new entries under a new directory created with - * configfs_create_dir(), and under all of its chidlren directories recursively. - * @sd configfs_dirent of the new directory to validate - * - * Caller must hold configfs_dirent_lock. - */ -static void configfs_dir_set_ready(struct configfs_dirent *sd) -{ - struct configfs_dirent *child_sd; - - sd->s_type &= ~CONFIGFS_USET_CREATING; - list_for_each_entry(child_sd, &sd->s_children, s_sibling) - if (child_sd->s_type & CONFIGFS_USET_CREATING) - configfs_dir_set_ready(child_sd); -} - -/* - * Check that a directory does not belong to a directory hierarchy being - * attached and not validated yet. - * @sd configfs_dirent of the directory to check - * - * @return non-zero iff the directory was validated - * - * Note: takes configfs_dirent_lock, so the result may change from false to true - * in two consecutive calls, but never from true to false. - */ -int configfs_dirent_is_ready(struct configfs_dirent *sd) -{ - int ret; - - spin_lock(&configfs_dirent_lock); - ret = !(sd->s_type & CONFIGFS_USET_CREATING); - spin_unlock(&configfs_dirent_lock); - - return ret; -} - -int configfs_create_link(struct configfs_symlink *sl, - struct dentry *parent, - struct dentry *dentry) -{ - int err = 0; - umode_t mode = S_IFLNK | S_IRWXUGO; - - err = configfs_make_dirent(parent->d_fsdata, dentry, sl, mode, - CONFIGFS_ITEM_LINK); - if (!err) { - err = configfs_create(dentry, mode, init_symlink); - if (err) { - struct configfs_dirent *sd = dentry->d_fsdata; - if (sd) { - spin_lock(&configfs_dirent_lock); - list_del_init(&sd->s_sibling); - spin_unlock(&configfs_dirent_lock); - configfs_put(sd); - } - } - } - return err; -} - -static void remove_dir(struct dentry * d) -{ - struct dentry * parent = dget(d->d_parent); - struct configfs_dirent * sd; - - sd = d->d_fsdata; - spin_lock(&configfs_dirent_lock); - list_del_init(&sd->s_sibling); - spin_unlock(&configfs_dirent_lock); - configfs_put(sd); - if (d->d_inode) - simple_rmdir(parent->d_inode,d); - - pr_debug(" o %s removing done (%d)\n",d->d_name.name, d->d_count); - - dput(parent); -} - -/** - * configfs_remove_dir - remove an config_item's directory. - * @item: config_item we're removing. - * - * The only thing special about this is that we remove any files in - * the directory before we remove the directory, and we've inlined - * what used to be configfs_rmdir() below, instead of calling separately. - * - * Caller holds the mutex of the item's inode - */ - -static void configfs_remove_dir(struct config_item * item) -{ - struct dentry * dentry = dget(item->ci_dentry); - - if (!dentry) - return; - - remove_dir(dentry); - /** - * Drop reference from dget() on entrance. - */ - dput(dentry); -} - - -/* attaches attribute's configfs_dirent to the dentry corresponding to the - * attribute file - */ -static int configfs_attach_attr(struct configfs_dirent * sd, struct dentry * dentry) -{ - struct configfs_attribute * attr = sd->s_element; - int error; - - dentry->d_fsdata = configfs_get(sd); - sd->s_dentry = dentry; - error = configfs_create(dentry, (attr->ca_mode & S_IALLUGO) | S_IFREG, - configfs_init_file); - if (error) { - configfs_put(sd); - return error; - } - - d_rehash(dentry); - - return 0; -} - -static struct dentry * configfs_lookup(struct inode *dir, - struct dentry *dentry, - struct nameidata *nd) -{ - struct configfs_dirent * parent_sd = dentry->d_parent->d_fsdata; - struct configfs_dirent * sd; - int found = 0; - int err; - - /* - * Fake invisibility if dir belongs to a group/default groups hierarchy - * being attached - * - * This forbids userspace to read/write attributes of items which may - * not complete their initialization, since the dentries of the - * attributes won't be instantiated. - */ - err = -ENOENT; - if (!configfs_dirent_is_ready(parent_sd)) - goto out; - - list_for_each_entry(sd, &parent_sd->s_children, s_sibling) { - if (sd->s_type & CONFIGFS_NOT_PINNED) { - const unsigned char * name = configfs_get_name(sd); - - if (strcmp(name, dentry->d_name.name)) - continue; - - found = 1; - err = configfs_attach_attr(sd, dentry); - break; - } - } - - if (!found) { - /* - * If it doesn't exist and it isn't a NOT_PINNED item, - * it must be negative. - */ - if (dentry->d_name.len > NAME_MAX) - return ERR_PTR(-ENAMETOOLONG); - d_add(dentry, NULL); - return NULL; - } - -out: - return ERR_PTR(err); -} - -/* - * Only subdirectories count here. Files (CONFIGFS_NOT_PINNED) are - * attributes and are removed by rmdir(). We recurse, setting - * CONFIGFS_USET_DROPPING on all children that are candidates for - * default detach. - * If there is an error, the caller will reset the flags via - * configfs_detach_rollback(). - */ -static int configfs_detach_prep(struct dentry *dentry, struct mutex **wait_mutex) -{ - struct configfs_dirent *parent_sd = dentry->d_fsdata; - struct configfs_dirent *sd; - int ret; - - /* Mark that we're trying to drop the group */ - parent_sd->s_type |= CONFIGFS_USET_DROPPING; - - ret = -EBUSY; - if (!list_empty(&parent_sd->s_links)) - goto out; - - ret = 0; - list_for_each_entry(sd, &parent_sd->s_children, s_sibling) { - if (!sd->s_element || - (sd->s_type & CONFIGFS_NOT_PINNED)) - continue; - if (sd->s_type & CONFIGFS_USET_DEFAULT) { - /* Abort if racing with mkdir() */ - if (sd->s_type & CONFIGFS_USET_IN_MKDIR) { - if (wait_mutex) - *wait_mutex = &sd->s_dentry->d_inode->i_mutex; - return -EAGAIN; - } - - /* - * Yup, recursive. If there's a problem, blame - * deep nesting of default_groups - */ - ret = configfs_detach_prep(sd->s_dentry, wait_mutex); - if (!ret) - continue; - } else - ret = -ENOTEMPTY; - - break; - } - -out: - return ret; -} - -/* - * Walk the tree, resetting CONFIGFS_USET_DROPPING wherever it was - * set. - */ -static void configfs_detach_rollback(struct dentry *dentry) -{ - struct configfs_dirent *parent_sd = dentry->d_fsdata; - struct configfs_dirent *sd; - - parent_sd->s_type &= ~CONFIGFS_USET_DROPPING; - - list_for_each_entry(sd, &parent_sd->s_children, s_sibling) - if (sd->s_type & CONFIGFS_USET_DEFAULT) - configfs_detach_rollback(sd->s_dentry); -} - -static void detach_attrs(struct config_item * item) -{ - struct dentry * dentry = dget(item->ci_dentry); - struct configfs_dirent * parent_sd; - struct configfs_dirent * sd, * tmp; - - if (!dentry) - return; - - pr_debug("configfs %s: dropping attrs for dir\n", - dentry->d_name.name); - - parent_sd = dentry->d_fsdata; - list_for_each_entry_safe(sd, tmp, &parent_sd->s_children, s_sibling) { - if (!sd->s_element || !(sd->s_type & CONFIGFS_NOT_PINNED)) - continue; - spin_lock(&configfs_dirent_lock); - list_del_init(&sd->s_sibling); - spin_unlock(&configfs_dirent_lock); - configfs_drop_dentry(sd, dentry); - configfs_put(sd); - } - - /** - * Drop reference from dget() on entrance. - */ - dput(dentry); -} - -static int populate_attrs(struct config_item *item) -{ - struct config_item_type *t = item->ci_type; - struct configfs_attribute *attr; - int error = 0; - int i; - - if (!t) - return -EINVAL; - if (t->ct_attrs) { - for (i = 0; (attr = t->ct_attrs[i]) != NULL; i++) { - if ((error = configfs_create_file(item, attr))) - break; - } - } - - if (error) - detach_attrs(item); - - return error; -} - -static int configfs_attach_group(struct config_item *parent_item, - struct config_item *item, - struct dentry *dentry); -static void configfs_detach_group(struct config_item *item); - -static void detach_groups(struct config_group *group) -{ - struct dentry * dentry = dget(group->cg_item.ci_dentry); - struct dentry *child; - struct configfs_dirent *parent_sd; - struct configfs_dirent *sd, *tmp; - - if (!dentry) - return; - - parent_sd = dentry->d_fsdata; - list_for_each_entry_safe(sd, tmp, &parent_sd->s_children, s_sibling) { - if (!sd->s_element || - !(sd->s_type & CONFIGFS_USET_DEFAULT)) - continue; - - child = sd->s_dentry; - - mutex_lock(&child->d_inode->i_mutex); - - configfs_detach_group(sd->s_element); - child->d_inode->i_flags |= S_DEAD; - dont_mount(child); - - mutex_unlock(&child->d_inode->i_mutex); - - d_delete(child); - dput(child); - } - - /** - * Drop reference from dget() on entrance. - */ - dput(dentry); -} - -/* - * This fakes mkdir(2) on a default_groups[] entry. It - * creates a dentry, attachs it, and then does fixup - * on the sd->s_type. - * - * We could, perhaps, tweak our parent's ->mkdir for a minute and - * try using vfs_mkdir. Just a thought. - */ -static int create_default_group(struct config_group *parent_group, - struct config_group *group) -{ - int ret; - struct qstr name; - struct configfs_dirent *sd; - /* We trust the caller holds a reference to parent */ - struct dentry *child, *parent = parent_group->cg_item.ci_dentry; - - if (!group->cg_item.ci_name) - group->cg_item.ci_name = group->cg_item.ci_namebuf; - name.name = group->cg_item.ci_name; - name.len = strlen(name.name); - name.hash = full_name_hash(name.name, name.len); - - ret = -ENOMEM; - child = d_alloc(parent, &name); - if (child) { - d_add(child, NULL); - - ret = configfs_attach_group(&parent_group->cg_item, - &group->cg_item, child); - if (!ret) { - sd = child->d_fsdata; - sd->s_type |= CONFIGFS_USET_DEFAULT; - } else { - BUG_ON(child->d_inode); - d_drop(child); - dput(child); - } - } - - return ret; -} - -static int populate_groups(struct config_group *group) -{ - struct config_group *new_group; - int ret = 0; - int i; - - if (group->default_groups) { - for (i = 0; group->default_groups[i]; i++) { - new_group = group->default_groups[i]; - - ret = create_default_group(group, new_group); - if (ret) { - detach_groups(group); - break; - } - } - } - - return ret; -} - -/* - * All of link_obj/unlink_obj/link_group/unlink_group require that - * subsys->su_mutex is held. - */ - -static void unlink_obj(struct config_item *item) -{ - struct config_group *group; - - group = item->ci_group; - if (group) { - list_del_init(&item->ci_entry); - - item->ci_group = NULL; - item->ci_parent = NULL; - - /* Drop the reference for ci_entry */ - config_item_put(item); - - /* Drop the reference for ci_parent */ - config_group_put(group); - } -} - -static void link_obj(struct config_item *parent_item, struct config_item *item) -{ - /* - * Parent seems redundant with group, but it makes certain - * traversals much nicer. - */ - item->ci_parent = parent_item; - - /* - * We hold a reference on the parent for the child's ci_parent - * link. - */ - item->ci_group = config_group_get(to_config_group(parent_item)); - list_add_tail(&item->ci_entry, &item->ci_group->cg_children); - - /* - * We hold a reference on the child for ci_entry on the parent's - * cg_children - */ - config_item_get(item); -} - -static void unlink_group(struct config_group *group) -{ - int i; - struct config_group *new_group; - - if (group->default_groups) { - for (i = 0; group->default_groups[i]; i++) { - new_group = group->default_groups[i]; - unlink_group(new_group); - } - } - - group->cg_subsys = NULL; - unlink_obj(&group->cg_item); -} - -static void link_group(struct config_group *parent_group, struct config_group *group) -{ - int i; - struct config_group *new_group; - struct configfs_subsystem *subsys = NULL; /* gcc is a turd */ - - link_obj(&parent_group->cg_item, &group->cg_item); - - if (parent_group->cg_subsys) - subsys = parent_group->cg_subsys; - else if (configfs_is_root(&parent_group->cg_item)) - subsys = to_configfs_subsystem(group); - else - BUG(); - group->cg_subsys = subsys; - - if (group->default_groups) { - for (i = 0; group->default_groups[i]; i++) { - new_group = group->default_groups[i]; - link_group(group, new_group); - } - } -} - -/* - * The goal is that configfs_attach_item() (and - * configfs_attach_group()) can be called from either the VFS or this - * module. That is, they assume that the items have been created, - * the dentry allocated, and the dcache is all ready to go. - * - * If they fail, they must clean up after themselves as if they - * had never been called. The caller (VFS or local function) will - * handle cleaning up the dcache bits. - * - * configfs_detach_group() and configfs_detach_item() behave similarly on - * the way out. They assume that the proper semaphores are held, they - * clean up the configfs items, and they expect their callers will - * handle the dcache bits. - */ -static int configfs_attach_item(struct config_item *parent_item, - struct config_item *item, - struct dentry *dentry) -{ - int ret; - - ret = configfs_create_dir(item, dentry); - if (!ret) { - ret = populate_attrs(item); - if (ret) { - /* - * We are going to remove an inode and its dentry but - * the VFS may already have hit and used them. Thus, - * we must lock them as rmdir() would. - */ - mutex_lock(&dentry->d_inode->i_mutex); - configfs_remove_dir(item); - dentry->d_inode->i_flags |= S_DEAD; - dont_mount(dentry); - mutex_unlock(&dentry->d_inode->i_mutex); - d_delete(dentry); - } - } - - return ret; -} - -/* Caller holds the mutex of the item's inode */ -static void configfs_detach_item(struct config_item *item) -{ - detach_attrs(item); - configfs_remove_dir(item); -} - -static int configfs_attach_group(struct config_item *parent_item, - struct config_item *item, - struct dentry *dentry) -{ - int ret; - struct configfs_dirent *sd; - - ret = configfs_attach_item(parent_item, item, dentry); - if (!ret) { - sd = dentry->d_fsdata; - sd->s_type |= CONFIGFS_USET_DIR; - - /* - * FYI, we're faking mkdir in populate_groups() - * We must lock the group's inode to avoid races with the VFS - * which can already hit the inode and try to add/remove entries - * under it. - * - * We must also lock the inode to remove it safely in case of - * error, as rmdir() would. - */ - mutex_lock_nested(&dentry->d_inode->i_mutex, I_MUTEX_CHILD); - configfs_adjust_dir_dirent_depth_before_populate(sd); - ret = populate_groups(to_config_group(item)); - if (ret) { - configfs_detach_item(item); - dentry->d_inode->i_flags |= S_DEAD; - dont_mount(dentry); - } - configfs_adjust_dir_dirent_depth_after_populate(sd); - mutex_unlock(&dentry->d_inode->i_mutex); - if (ret) - d_delete(dentry); - } - - return ret; -} - -/* Caller holds the mutex of the group's inode */ -static void configfs_detach_group(struct config_item *item) -{ - detach_groups(to_config_group(item)); - configfs_detach_item(item); -} - -/* - * After the item has been detached from the filesystem view, we are - * ready to tear it out of the hierarchy. Notify the client before - * we do that so they can perform any cleanup that requires - * navigating the hierarchy. A client does not need to provide this - * callback. The subsystem semaphore MUST be held by the caller, and - * references must be valid for both items. It also assumes the - * caller has validated ci_type. - */ -static void client_disconnect_notify(struct config_item *parent_item, - struct config_item *item) -{ - struct config_item_type *type; - - type = parent_item->ci_type; - BUG_ON(!type); - - if (type->ct_group_ops && type->ct_group_ops->disconnect_notify) - type->ct_group_ops->disconnect_notify(to_config_group(parent_item), - item); -} - -/* - * Drop the initial reference from make_item()/make_group() - * This function assumes that reference is held on item - * and that item holds a valid reference to the parent. Also, it - * assumes the caller has validated ci_type. - */ -static void client_drop_item(struct config_item *parent_item, - struct config_item *item) -{ - struct config_item_type *type; - - type = parent_item->ci_type; - BUG_ON(!type); - - /* - * If ->drop_item() exists, it is responsible for the - * config_item_put(). - */ - if (type->ct_group_ops && type->ct_group_ops->drop_item) - type->ct_group_ops->drop_item(to_config_group(parent_item), - item); - else - config_item_put(item); -} - -#ifdef DEBUG -static void configfs_dump_one(struct configfs_dirent *sd, int level) -{ - printk(KERN_INFO "%*s\"%s\":\n", level, " ", configfs_get_name(sd)); - -#define type_print(_type) if (sd->s_type & _type) printk(KERN_INFO "%*s %s\n", level, " ", #_type); - type_print(CONFIGFS_ROOT); - type_print(CONFIGFS_DIR); - type_print(CONFIGFS_ITEM_ATTR); - type_print(CONFIGFS_ITEM_LINK); - type_print(CONFIGFS_USET_DIR); - type_print(CONFIGFS_USET_DEFAULT); - type_print(CONFIGFS_USET_DROPPING); -#undef type_print -} - -static int configfs_dump(struct configfs_dirent *sd, int level) -{ - struct configfs_dirent *child_sd; - int ret = 0; - - configfs_dump_one(sd, level); - - if (!(sd->s_type & (CONFIGFS_DIR|CONFIGFS_ROOT))) - return 0; - - list_for_each_entry(child_sd, &sd->s_children, s_sibling) { - ret = configfs_dump(child_sd, level + 2); - if (ret) - break; - } - - return ret; -} -#endif - - -/* - * configfs_depend_item() and configfs_undepend_item() - * - * WARNING: Do not call these from a configfs callback! - * - * This describes these functions and their helpers. - * - * Allow another kernel system to depend on a config_item. If this - * happens, the item cannot go away until the dependent can live without - * it. The idea is to give client modules as simple an interface as - * possible. When a system asks them to depend on an item, they just - * call configfs_depend_item(). If the item is live and the client - * driver is in good shape, we'll happily do the work for them. - * - * Why is the locking complex? Because configfs uses the VFS to handle - * all locking, but this function is called outside the normal - * VFS->configfs path. So it must take VFS locks to prevent the - * VFS->configfs stuff (configfs_mkdir(), configfs_rmdir(), etc). This is - * why you can't call these functions underneath configfs callbacks. - * - * Note, btw, that this can be called at *any* time, even when a configfs - * subsystem isn't registered, or when configfs is loading or unloading. - * Just like configfs_register_subsystem(). So we take the same - * precautions. We pin the filesystem. We lock configfs_dirent_lock. - * If we can find the target item in the - * configfs tree, it must be part of the subsystem tree as well, so we - * do not need the subsystem semaphore. Holding configfs_dirent_lock helps - * locking out mkdir() and rmdir(), who might be racing us. - */ - -/* - * configfs_depend_prep() - * - * Only subdirectories count here. Files (CONFIGFS_NOT_PINNED) are - * attributes. This is similar but not the same to configfs_detach_prep(). - * Note that configfs_detach_prep() expects the parent to be locked when it - * is called, but we lock the parent *inside* configfs_depend_prep(). We - * do that so we can unlock it if we find nothing. - * - * Here we do a depth-first search of the dentry hierarchy looking for - * our object. - * We deliberately ignore items tagged as dropping since they are virtually - * dead, as well as items in the middle of attachment since they virtually - * do not exist yet. This completes the locking out of racing mkdir() and - * rmdir(). - * Note: subdirectories in the middle of attachment start with s_type = - * CONFIGFS_DIR|CONFIGFS_USET_CREATING set by create_dir(). When - * CONFIGFS_USET_CREATING is set, we ignore the item. The actual set of - * s_type is in configfs_new_dirent(), which has configfs_dirent_lock. - * - * If the target is not found, -ENOENT is bubbled up. - * - * This adds a requirement that all config_items be unique! - * - * This is recursive. There isn't - * much on the stack, though, so folks that need this function - be careful - * about your stack! Patches will be accepted to make it iterative. - */ -static int configfs_depend_prep(struct dentry *origin, - struct config_item *target) -{ - struct configfs_dirent *child_sd, *sd = origin->d_fsdata; - int ret = 0; - - BUG_ON(!origin || !sd); - - if (sd->s_element == target) /* Boo-yah */ - goto out; - - list_for_each_entry(child_sd, &sd->s_children, s_sibling) { - if ((child_sd->s_type & CONFIGFS_DIR) && - !(child_sd->s_type & CONFIGFS_USET_DROPPING) && - !(child_sd->s_type & CONFIGFS_USET_CREATING)) { - ret = configfs_depend_prep(child_sd->s_dentry, - target); - if (!ret) - goto out; /* Child path boo-yah */ - } - } - - /* We looped all our children and didn't find target */ - ret = -ENOENT; - -out: - return ret; -} - -int configfs_depend_item(struct configfs_subsystem *subsys, - struct config_item *target) -{ - int ret; - struct configfs_dirent *p, *root_sd, *subsys_sd = NULL; - struct config_item *s_item = &subsys->su_group.cg_item; - struct dentry *root; - - /* - * Pin the configfs filesystem. This means we can safely access - * the root of the configfs filesystem. - */ - root = configfs_pin_fs(); - if (IS_ERR(root)) - return PTR_ERR(root); - - /* - * Next, lock the root directory. We're going to check that the - * subsystem is really registered, and so we need to lock out - * configfs_[un]register_subsystem(). - */ - mutex_lock(&root->d_inode->i_mutex); - - root_sd = root->d_fsdata; - - list_for_each_entry(p, &root_sd->s_children, s_sibling) { - if (p->s_type & CONFIGFS_DIR) { - if (p->s_element == s_item) { - subsys_sd = p; - break; - } - } - } - - if (!subsys_sd) { - ret = -ENOENT; - goto out_unlock_fs; - } - - /* Ok, now we can trust subsys/s_item */ - - spin_lock(&configfs_dirent_lock); - /* Scan the tree, return 0 if found */ - ret = configfs_depend_prep(subsys_sd->s_dentry, target); - if (ret) - goto out_unlock_dirent_lock; - - /* - * We are sure that the item is not about to be removed by rmdir(), and - * not in the middle of attachment by mkdir(). - */ - p = target->ci_dentry->d_fsdata; - p->s_dependent_count += 1; - -out_unlock_dirent_lock: - spin_unlock(&configfs_dirent_lock); -out_unlock_fs: - mutex_unlock(&root->d_inode->i_mutex); - - /* - * If we succeeded, the fs is pinned via other methods. If not, - * we're done with it anyway. So release_fs() is always right. - */ - configfs_release_fs(); - - return ret; -} -EXPORT_SYMBOL(configfs_depend_item); - -/* - * Release the dependent linkage. This is much simpler than - * configfs_depend_item() because we know that that the client driver is - * pinned, thus the subsystem is pinned, and therefore configfs is pinned. - */ -void configfs_undepend_item(struct configfs_subsystem *subsys, - struct config_item *target) -{ - struct configfs_dirent *sd; - - /* - * Since we can trust everything is pinned, we just need - * configfs_dirent_lock. - */ - spin_lock(&configfs_dirent_lock); - - sd = target->ci_dentry->d_fsdata; - BUG_ON(sd->s_dependent_count < 1); - - sd->s_dependent_count -= 1; - - /* - * After this unlock, we cannot trust the item to stay alive! - * DO NOT REFERENCE item after this unlock. - */ - spin_unlock(&configfs_dirent_lock); -} -EXPORT_SYMBOL(configfs_undepend_item); - -static int configfs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode) -{ - int ret = 0; - int module_got = 0; - struct config_group *group = NULL; - struct config_item *item = NULL; - struct config_item *parent_item; - struct configfs_subsystem *subsys; - struct configfs_dirent *sd; - struct config_item_type *type; - struct module *subsys_owner = NULL, *new_item_owner = NULL; - char *name; - - sd = dentry->d_parent->d_fsdata; - - /* - * Fake invisibility if dir belongs to a group/default groups hierarchy - * being attached - */ - if (!configfs_dirent_is_ready(sd)) { - ret = -ENOENT; - goto out; - } - - if (!(sd->s_type & CONFIGFS_USET_DIR)) { - ret = -EPERM; - goto out; - } - - /* Get a working ref for the duration of this function */ - parent_item = configfs_get_config_item(dentry->d_parent); - type = parent_item->ci_type; - subsys = to_config_group(parent_item)->cg_subsys; - BUG_ON(!subsys); - - if (!type || !type->ct_group_ops || - (!type->ct_group_ops->make_group && - !type->ct_group_ops->make_item)) { - ret = -EPERM; /* Lack-of-mkdir returns -EPERM */ - goto out_put; - } - - /* - * The subsystem may belong to a different module than the item - * being created. We don't want to safely pin the new item but - * fail to pin the subsystem it sits under. - */ - if (!subsys->su_group.cg_item.ci_type) { - ret = -EINVAL; - goto out_put; - } - subsys_owner = subsys->su_group.cg_item.ci_type->ct_owner; - if (!try_module_get(subsys_owner)) { - ret = -EINVAL; - goto out_put; - } - - name = kmalloc(dentry->d_name.len + 1, GFP_KERNEL); - if (!name) { - ret = -ENOMEM; - goto out_subsys_put; - } - - snprintf(name, dentry->d_name.len + 1, "%s", dentry->d_name.name); - - mutex_lock(&subsys->su_mutex); - if (type->ct_group_ops->make_group) { - group = type->ct_group_ops->make_group(to_config_group(parent_item), name); - if (!group) - group = ERR_PTR(-ENOMEM); - if (!IS_ERR(group)) { - link_group(to_config_group(parent_item), group); - item = &group->cg_item; - } else - ret = PTR_ERR(group); - } else { - item = type->ct_group_ops->make_item(to_config_group(parent_item), name); - if (!item) - item = ERR_PTR(-ENOMEM); - if (!IS_ERR(item)) - link_obj(parent_item, item); - else - ret = PTR_ERR(item); - } - mutex_unlock(&subsys->su_mutex); - - kfree(name); - if (ret) { - /* - * If ret != 0, then link_obj() was never called. - * There are no extra references to clean up. - */ - goto out_subsys_put; - } - - /* - * link_obj() has been called (via link_group() for groups). - * From here on out, errors must clean that up. - */ - - type = item->ci_type; - if (!type) { - ret = -EINVAL; - goto out_unlink; - } - - new_item_owner = type->ct_owner; - if (!try_module_get(new_item_owner)) { - ret = -EINVAL; - goto out_unlink; - } - - /* - * I hate doing it this way, but if there is - * an error, module_put() probably should - * happen after any cleanup. - */ - module_got = 1; - - /* - * Make racing rmdir() fail if it did not tag parent with - * CONFIGFS_USET_DROPPING - * Note: if CONFIGFS_USET_DROPPING is already set, attach_group() will - * fail and let rmdir() terminate correctly - */ - spin_lock(&configfs_dirent_lock); - /* This will make configfs_detach_prep() fail */ - sd->s_type |= CONFIGFS_USET_IN_MKDIR; - spin_unlock(&configfs_dirent_lock); - - if (group) - ret = configfs_attach_group(parent_item, item, dentry); - else - ret = configfs_attach_item(parent_item, item, dentry); - - spin_lock(&configfs_dirent_lock); - sd->s_type &= ~CONFIGFS_USET_IN_MKDIR; - if (!ret) - configfs_dir_set_ready(dentry->d_fsdata); - spin_unlock(&configfs_dirent_lock); - -out_unlink: - if (ret) { - /* Tear down everything we built up */ - mutex_lock(&subsys->su_mutex); - - client_disconnect_notify(parent_item, item); - if (group) - unlink_group(group); - else - unlink_obj(item); - client_drop_item(parent_item, item); - - mutex_unlock(&subsys->su_mutex); - - if (module_got) - module_put(new_item_owner); - } - -out_subsys_put: - if (ret) - module_put(subsys_owner); - -out_put: - /* - * link_obj()/link_group() took a reference from child->parent, - * so the parent is safely pinned. We can drop our working - * reference. - */ - config_item_put(parent_item); - -out: - return ret; -} - -static int configfs_rmdir(struct inode *dir, struct dentry *dentry) -{ - struct config_item *parent_item; - struct config_item *item; - struct configfs_subsystem *subsys; - struct configfs_dirent *sd; - struct module *subsys_owner = NULL, *dead_item_owner = NULL; - int ret; - - sd = dentry->d_fsdata; - if (sd->s_type & CONFIGFS_USET_DEFAULT) - return -EPERM; - - /* Get a working ref until we have the child */ - parent_item = configfs_get_config_item(dentry->d_parent); - subsys = to_config_group(parent_item)->cg_subsys; - BUG_ON(!subsys); - - if (!parent_item->ci_type) { - config_item_put(parent_item); - return -EINVAL; - } - - /* configfs_mkdir() shouldn't have allowed this */ - BUG_ON(!subsys->su_group.cg_item.ci_type); - subsys_owner = subsys->su_group.cg_item.ci_type->ct_owner; - - /* - * Ensure that no racing symlink() will make detach_prep() fail while - * the new link is temporarily attached - */ - do { - struct mutex *wait_mutex; - - mutex_lock(&configfs_symlink_mutex); - spin_lock(&configfs_dirent_lock); - /* - * Here's where we check for dependents. We're protected by - * configfs_dirent_lock. - * If no dependent, atomically tag the item as dropping. - */ - ret = sd->s_dependent_count ? -EBUSY : 0; - if (!ret) { - ret = configfs_detach_prep(dentry, &wait_mutex); - if (ret) - configfs_detach_rollback(dentry); - } - spin_unlock(&configfs_dirent_lock); - mutex_unlock(&configfs_symlink_mutex); - - if (ret) { - if (ret != -EAGAIN) { - config_item_put(parent_item); - return ret; - } - - /* Wait until the racing operation terminates */ - mutex_lock(wait_mutex); - mutex_unlock(wait_mutex); - } - } while (ret == -EAGAIN); - - /* Get a working ref for the duration of this function */ - item = configfs_get_config_item(dentry); - - /* Drop reference from above, item already holds one. */ - config_item_put(parent_item); - - if (item->ci_type) - dead_item_owner = item->ci_type->ct_owner; - - if (sd->s_type & CONFIGFS_USET_DIR) { - configfs_detach_group(item); - - mutex_lock(&subsys->su_mutex); - client_disconnect_notify(parent_item, item); - unlink_group(to_config_group(item)); - } else { - configfs_detach_item(item); - - mutex_lock(&subsys->su_mutex); - client_disconnect_notify(parent_item, item); - unlink_obj(item); - } - - client_drop_item(parent_item, item); - mutex_unlock(&subsys->su_mutex); - - /* Drop our reference from above */ - config_item_put(item); - - module_put(dead_item_owner); - module_put(subsys_owner); - - return 0; -} - -const struct inode_operations configfs_dir_inode_operations = { - .mkdir = configfs_mkdir, - .rmdir = configfs_rmdir, - .symlink = configfs_symlink, - .unlink = configfs_unlink, - .lookup = configfs_lookup, - .setattr = configfs_setattr, -}; - -const struct inode_operations configfs_root_inode_operations = { - .lookup = configfs_lookup, - .setattr = configfs_setattr, -}; - -#if 0 -int configfs_rename_dir(struct config_item * item, const char *new_name) -{ - int error = 0; - struct dentry * new_dentry, * parent; - - if (!strcmp(config_item_name(item), new_name)) - return -EINVAL; - - if (!item->parent) - return -EINVAL; - - down_write(&configfs_rename_sem); - parent = item->parent->dentry; - - mutex_lock(&parent->d_inode->i_mutex); - - new_dentry = lookup_one_len(new_name, parent, strlen(new_name)); - if (!IS_ERR(new_dentry)) { - if (!new_dentry->d_inode) { - error = config_item_set_name(item, "%s", new_name); - if (!error) { - d_add(new_dentry, NULL); - d_move(item->dentry, new_dentry); - } - else - d_delete(new_dentry); - } else - error = -EEXIST; - dput(new_dentry); - } - mutex_unlock(&parent->d_inode->i_mutex); - up_write(&configfs_rename_sem); - - return error; -} -#endif - -static int configfs_dir_open(struct inode *inode, struct file *file) -{ - struct dentry * dentry = file->f_path.dentry; - struct configfs_dirent * parent_sd = dentry->d_fsdata; - int err; - - mutex_lock(&dentry->d_inode->i_mutex); - /* - * Fake invisibility if dir belongs to a group/default groups hierarchy - * being attached - */ - err = -ENOENT; - if (configfs_dirent_is_ready(parent_sd)) { - file->private_data = configfs_new_dirent(parent_sd, NULL, 0); - if (IS_ERR(file->private_data)) - err = PTR_ERR(file->private_data); - else - err = 0; - } - mutex_unlock(&dentry->d_inode->i_mutex); - - return err; -} - -static int configfs_dir_close(struct inode *inode, struct file *file) -{ - struct dentry * dentry = file->f_path.dentry; - struct configfs_dirent * cursor = file->private_data; - - mutex_lock(&dentry->d_inode->i_mutex); - spin_lock(&configfs_dirent_lock); - list_del_init(&cursor->s_sibling); - spin_unlock(&configfs_dirent_lock); - mutex_unlock(&dentry->d_inode->i_mutex); - - release_configfs_dirent(cursor); - - return 0; -} - -/* Relationship between s_mode and the DT_xxx types */ -static inline unsigned char dt_type(struct configfs_dirent *sd) -{ - return (sd->s_mode >> 12) & 15; -} - -static int configfs_readdir(struct file * filp, void * dirent, filldir_t filldir) -{ - struct dentry *dentry = filp->f_path.dentry; - struct super_block *sb = dentry->d_sb; - struct configfs_dirent * parent_sd = dentry->d_fsdata; - struct configfs_dirent *cursor = filp->private_data; - struct list_head *p, *q = &cursor->s_sibling; - ino_t ino = 0; - int i = filp->f_pos; - - switch (i) { - case 0: - ino = dentry->d_inode->i_ino; - if (filldir(dirent, ".", 1, i, ino, DT_DIR) < 0) - break; - filp->f_pos++; - i++; - /* fallthrough */ - case 1: - ino = parent_ino(dentry); - if (filldir(dirent, "..", 2, i, ino, DT_DIR) < 0) - break; - filp->f_pos++; - i++; - /* fallthrough */ - default: - if (filp->f_pos == 2) { - spin_lock(&configfs_dirent_lock); - list_move(q, &parent_sd->s_children); - spin_unlock(&configfs_dirent_lock); - } - for (p=q->next; p!= &parent_sd->s_children; p=p->next) { - struct configfs_dirent *next; - const char * name; - int len; - struct inode *inode = NULL; - - next = list_entry(p, struct configfs_dirent, - s_sibling); - if (!next->s_element) - continue; - - name = configfs_get_name(next); - len = strlen(name); - - /* - * We'll have a dentry and an inode for - * PINNED items and for open attribute - * files. We lock here to prevent a race - * with configfs_d_iput() clearing - * s_dentry before calling iput(). - * - * Why do we go to the trouble? If - * someone has an attribute file open, - * the inode number should match until - * they close it. Beyond that, we don't - * care. - */ - spin_lock(&configfs_dirent_lock); - dentry = next->s_dentry; - if (dentry) - inode = dentry->d_inode; - if (inode) - ino = inode->i_ino; - spin_unlock(&configfs_dirent_lock); - if (!inode) - ino = iunique(sb, 2); - - if (filldir(dirent, name, len, filp->f_pos, ino, - dt_type(next)) < 0) - return 0; - - spin_lock(&configfs_dirent_lock); - list_move(q, p); - spin_unlock(&configfs_dirent_lock); - p = q; - filp->f_pos++; - } - } - return 0; -} - -static loff_t configfs_dir_lseek(struct file * file, loff_t offset, int origin) -{ - struct dentry * dentry = file->f_path.dentry; - - mutex_lock(&dentry->d_inode->i_mutex); - switch (origin) { - case 1: - offset += file->f_pos; - case 0: - if (offset >= 0) - break; - default: - mutex_unlock(&file->f_path.dentry->d_inode->i_mutex); - return -EINVAL; - } - if (offset != file->f_pos) { - file->f_pos = offset; - if (file->f_pos >= 2) { - struct configfs_dirent *sd = dentry->d_fsdata; - struct configfs_dirent *cursor = file->private_data; - struct list_head *p; - loff_t n = file->f_pos - 2; - - spin_lock(&configfs_dirent_lock); - list_del(&cursor->s_sibling); - p = sd->s_children.next; - while (n && p != &sd->s_children) { - struct configfs_dirent *next; - next = list_entry(p, struct configfs_dirent, - s_sibling); - if (next->s_element) - n--; - p = p->next; - } - list_add_tail(&cursor->s_sibling, p); - spin_unlock(&configfs_dirent_lock); - } - } - mutex_unlock(&dentry->d_inode->i_mutex); - return offset; -} - -const struct file_operations configfs_dir_operations = { - .open = configfs_dir_open, - .release = configfs_dir_close, - .llseek = configfs_dir_lseek, - .read = generic_read_dir, - .readdir = configfs_readdir, -}; - -int configfs_register_subsystem(struct configfs_subsystem *subsys) -{ - int err; - struct config_group *group = &subsys->su_group; - struct qstr name; - struct dentry *dentry; - struct dentry *root; - struct configfs_dirent *sd; - - root = configfs_pin_fs(); - if (IS_ERR(root)) - return PTR_ERR(root); - - if (!group->cg_item.ci_name) - group->cg_item.ci_name = group->cg_item.ci_namebuf; - - sd = root->d_fsdata; - link_group(to_config_group(sd->s_element), group); - - mutex_lock_nested(&root->d_inode->i_mutex, I_MUTEX_PARENT); - - name.name = group->cg_item.ci_name; - name.len = strlen(name.name); - name.hash = full_name_hash(name.name, name.len); - - err = -ENOMEM; - dentry = d_alloc(root, &name); - if (dentry) { - d_add(dentry, NULL); - - err = configfs_attach_group(sd->s_element, &group->cg_item, - dentry); - if (err) { - BUG_ON(dentry->d_inode); - d_drop(dentry); - dput(dentry); - } else { - spin_lock(&configfs_dirent_lock); - configfs_dir_set_ready(dentry->d_fsdata); - spin_unlock(&configfs_dirent_lock); - } - } - - mutex_unlock(&root->d_inode->i_mutex); - - if (err) { - unlink_group(group); - configfs_release_fs(); - } - - return err; -} - -void configfs_unregister_subsystem(struct configfs_subsystem *subsys) -{ - struct config_group *group = &subsys->su_group; - struct dentry *dentry = group->cg_item.ci_dentry; - struct dentry *root = dentry->d_sb->s_root; - - if (dentry->d_parent != root) { - printk(KERN_ERR "configfs: Tried to unregister non-subsystem!\n"); - return; - } - - mutex_lock_nested(&root->d_inode->i_mutex, - I_MUTEX_PARENT); - mutex_lock_nested(&dentry->d_inode->i_mutex, I_MUTEX_CHILD); - mutex_lock(&configfs_symlink_mutex); - spin_lock(&configfs_dirent_lock); - if (configfs_detach_prep(dentry, NULL)) { - printk(KERN_ERR "configfs: Tried to unregister non-empty subsystem!\n"); - } - spin_unlock(&configfs_dirent_lock); - mutex_unlock(&configfs_symlink_mutex); - configfs_detach_group(&group->cg_item); - dentry->d_inode->i_flags |= S_DEAD; - dont_mount(dentry); - mutex_unlock(&dentry->d_inode->i_mutex); - - d_delete(dentry); - - mutex_unlock(&root->d_inode->i_mutex); - - dput(dentry); - - unlink_group(group); - configfs_release_fs(); -} - -EXPORT_SYMBOL(configfs_register_subsystem); -EXPORT_SYMBOL(configfs_unregister_subsystem); |