| // SPDX-License-Identifier: GPL-2.0-or-later |
| /* -*- mode: c; c-basic-offset: 8; -*- |
| * vim: noexpandtab sw=8 ts=8 sts=0: |
| * |
| * dir.c - Operations for configfs directories. |
| * |
| * 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/fsnotify.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) { |
| /* Coordinate with configfs_readdir */ |
| spin_lock(&configfs_dirent_lock); |
| /* |
| * Set sd->s_dentry to null only when this dentry is the one |
| * that is going to be killed. Otherwise configfs_d_iput may |
| * run just after configfs_attach_attr and set sd->s_dentry to |
| * NULL even it's still in use. |
| */ |
| if (sd->s_dentry == dentry) |
| sd->s_dentry = NULL; |
| |
| spin_unlock(&configfs_dirent_lock); |
| configfs_put(sd); |
| } |
| iput(inode); |
| } |
| |
| const struct dentry_operations configfs_dentry_ops = { |
| .d_iput = configfs_d_iput, |
| .d_delete = always_delete_dentry, |
| }; |
| |
| #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 */ |
| |
| static struct configfs_fragment *new_fragment(void) |
| { |
| struct configfs_fragment *p; |
| |
| p = kmalloc(sizeof(struct configfs_fragment), GFP_KERNEL); |
| if (p) { |
| atomic_set(&p->frag_count, 1); |
| init_rwsem(&p->frag_sem); |
| p->frag_dead = false; |
| } |
| return p; |
| } |
| |
| void put_fragment(struct configfs_fragment *frag) |
| { |
| if (frag && atomic_dec_and_test(&frag->frag_count)) |
| kfree(frag); |
| } |
| |
| struct configfs_fragment *get_fragment(struct configfs_fragment *frag) |
| { |
| if (likely(frag)) |
| atomic_inc(&frag->frag_count); |
| return frag; |
| } |
| |
| /* |
| * 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_fragment *frag) |
| { |
| 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); |
| } |
| sd->s_frag = get_fragment(frag); |
| 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_fragment *frag) |
| { |
| struct configfs_dirent * sd; |
| |
| sd = configfs_new_dirent(parent_sd, element, type, frag); |
| 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 void 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); |
| } |
| |
| static void configfs_init_file(struct inode * inode) |
| { |
| inode->i_size = PAGE_SIZE; |
| inode->i_fop = &configfs_file_operations; |
| } |
| |
| static void configfs_init_bin_file(struct inode *inode) |
| { |
| inode->i_size = 0; |
| inode->i_fop = &configfs_bin_file_operations; |
| } |
| |
| static void init_symlink(struct inode * inode) |
| { |
| inode->i_op = &configfs_symlink_inode_operations; |
| } |
| |
| /** |
| * 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, |
| struct configfs_fragment *frag) |
| { |
| int error; |
| umode_t mode = S_IFDIR| S_IRWXU | S_IRUGO | S_IXUGO; |
| struct dentry *p = dentry->d_parent; |
| |
| BUG_ON(!item); |
| |
| error = configfs_dirent_exists(p->d_fsdata, dentry->d_name.name); |
| if (unlikely(error)) |
| return error; |
| |
| error = configfs_make_dirent(p->d_fsdata, dentry, item, mode, |
| CONFIGFS_DIR | CONFIGFS_USET_CREATING, |
| frag); |
| if (unlikely(error)) |
| return error; |
| |
| configfs_set_dir_dirent_depth(p->d_fsdata, dentry->d_fsdata); |
| error = configfs_create(dentry, mode, init_dir); |
| if (!error) { |
| inc_nlink(d_inode(p)); |
| item->ci_dentry = dentry; |
| } else { |
| 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 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; |
| struct configfs_dirent *p = parent->d_fsdata; |
| |
| err = configfs_make_dirent(p, dentry, sl, mode, |
| CONFIGFS_ITEM_LINK, p->s_frag); |
| 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_really_is_positive(d)) |
| simple_rmdir(d_inode(parent),d); |
| |
| pr_debug(" o %pd removing done (%d)\n", d, d_count(d)); |
| |
| 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; |
| |
| spin_lock(&configfs_dirent_lock); |
| dentry->d_fsdata = configfs_get(sd); |
| sd->s_dentry = dentry; |
| spin_unlock(&configfs_dirent_lock); |
| |
| error = configfs_create(dentry, (attr->ca_mode & S_IALLUGO) | S_IFREG, |
| (sd->s_type & CONFIGFS_ITEM_BIN_ATTR) ? |
| configfs_init_bin_file : |
| configfs_init_file); |
| if (error) |
| configfs_put(sd); |
| return error; |
| } |
| |
| static struct dentry * configfs_lookup(struct inode *dir, |
| struct dentry *dentry, |
| unsigned int flags) |
| { |
| 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 dentry **wait) |
| { |
| 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) |
| *wait= dget(sd->s_dentry); |
| return -EAGAIN; |
| } |
| |
| /* |
| * Yup, recursive. If there's a problem, blame |
| * deep nesting of default_groups |
| */ |
| ret = configfs_detach_prep(sd->s_dentry, wait); |
| 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) |
| { |
| const struct config_item_type *t = item->ci_type; |
| struct configfs_attribute *attr; |
| struct configfs_bin_attribute *bin_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 (t->ct_bin_attrs) { |
| for (i = 0; (bin_attr = t->ct_bin_attrs[i]) != NULL; i++) { |
| error = configfs_create_bin_file(item, bin_attr); |
| if (error) |
| 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, |
| struct configfs_fragment *frag); |
| 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; |
| |
| inode_lock(d_inode(child)); |
| |
| configfs_detach_group(sd->s_element); |
| d_inode(child)->i_flags |= S_DEAD; |
| dont_mount(child); |
| |
| inode_unlock(d_inode(child)); |
| |
| 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, |
| struct configfs_fragment *frag) |
| { |
| int ret; |
| 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; |
| |
| ret = -ENOMEM; |
| child = d_alloc_name(parent, group->cg_item.ci_name); |
| if (child) { |
| d_add(child, NULL); |
| |
| ret = configfs_attach_group(&parent_group->cg_item, |
| &group->cg_item, child, frag); |
| if (!ret) { |
| sd = child->d_fsdata; |
| sd->s_type |= CONFIGFS_USET_DEFAULT; |
| } else { |
| BUG_ON(d_inode(child)); |
| d_drop(child); |
| dput(child); |
| } |
| } |
| |
| return ret; |
| } |
| |
| static int populate_groups(struct config_group *group, |
| struct configfs_fragment *frag) |
| { |
| struct config_group *new_group; |
| int ret = 0; |
| |
| list_for_each_entry(new_group, &group->default_groups, group_entry) { |
| ret = create_default_group(group, new_group, frag); |
| if (ret) { |
| detach_groups(group); |
| break; |
| } |
| } |
| |
| return ret; |
| } |
| |
| void configfs_remove_default_groups(struct config_group *group) |
| { |
| struct config_group *g, *n; |
| |
| list_for_each_entry_safe(g, n, &group->default_groups, group_entry) { |
| list_del(&g->group_entry); |
| config_item_put(&g->cg_item); |
| } |
| } |
| EXPORT_SYMBOL(configfs_remove_default_groups); |
| |
| /* |
| * 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) |
| { |
| struct config_group *new_group; |
| |
| list_for_each_entry(new_group, &group->default_groups, group_entry) |
| 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) |
| { |
| 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; |
| |
| list_for_each_entry(new_group, &group->default_groups, group_entry) |
| 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, |
| struct configfs_fragment *frag) |
| { |
| int ret; |
| |
| ret = configfs_create_dir(item, dentry, frag); |
| 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. |
| */ |
| inode_lock(d_inode(dentry)); |
| configfs_remove_dir(item); |
| d_inode(dentry)->i_flags |= S_DEAD; |
| dont_mount(dentry); |
| inode_unlock(d_inode(dentry)); |
| 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, |
| struct configfs_fragment *frag) |
| { |
| int ret; |
| struct configfs_dirent *sd; |
| |
| ret = configfs_attach_item(parent_item, item, dentry, frag); |
| 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. |
| */ |
| inode_lock_nested(d_inode(dentry), I_MUTEX_CHILD); |
| configfs_adjust_dir_dirent_depth_before_populate(sd); |
| ret = populate_groups(to_config_group(item), frag); |
| if (ret) { |
| configfs_detach_item(item); |
| d_inode(dentry)->i_flags |= S_DEAD; |
| dont_mount(dentry); |
| } |
| configfs_adjust_dir_dirent_depth_after_populate(sd); |
| inode_unlock(d_inode(dentry)); |
| 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) |
| { |
| const 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) |
| { |
| const 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) |
| { |
| pr_info("%*s\"%s\":\n", level, " ", configfs_get_name(sd)); |
| |
| #define type_print(_type) if (sd->s_type & _type) pr_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; |
| int ret = 0; |
| |
| BUG_ON(!origin || !origin->d_fsdata); |
| sd = origin->d_fsdata; |
| |
| 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; |
| } |
| |
| static int configfs_do_depend_item(struct dentry *subsys_dentry, |
| struct config_item *target) |
| { |
| struct configfs_dirent *p; |
| int ret; |
| |
| spin_lock(&configfs_dirent_lock); |
| /* Scan the tree, return 0 if found */ |
| ret = configfs_depend_prep(subsys_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); |
| |
| return ret; |
| } |
| |
| static inline struct configfs_dirent * |
| configfs_find_subsys_dentry(struct configfs_dirent *root_sd, |
| struct config_item *subsys_item) |
| { |
| struct configfs_dirent *p; |
| struct configfs_dirent *ret = NULL; |
| |
| list_for_each_entry(p, &root_sd->s_children, s_sibling) { |
| if (p->s_type & CONFIGFS_DIR && |
| p->s_element == subsys_item) { |
| ret = p; |
| break; |
| } |
| } |
| |
| return ret; |
| } |
| |
| |
| int configfs_depend_item(struct configfs_subsystem *subsys, |
| struct config_item *target) |
| { |
| int ret; |
| struct configfs_dirent *subsys_sd; |
| 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(). |
| */ |
| inode_lock(d_inode(root)); |
| |
| subsys_sd = configfs_find_subsys_dentry(root->d_fsdata, s_item); |
| if (!subsys_sd) { |
| ret = -ENOENT; |
| goto out_unlock_fs; |
| } |
| |
| /* Ok, now we can trust subsys/s_item */ |
| ret = configfs_do_depend_item(subsys_sd->s_dentry, target); |
| |
| out_unlock_fs: |
| inode_unlock(d_inode(root)); |
| |
| /* |
| * 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 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); |
| |
| /* |
| * caller_subsys is a caller's subsystem not target's. This is used to |
| * determine if we should lock root and check subsys or not. When we are |
| * in the same subsystem as our target there is no need to do locking as |
| * we know that subsys is valid and is not unregistered during this function |
| * as we are called from callback of one of his children and VFS holds a lock |
| * on some inode. Otherwise we have to lock our root to ensure that target's |
| * subsystem it is not unregistered during this function. |
| */ |
| int configfs_depend_item_unlocked(struct configfs_subsystem *caller_subsys, |
| struct config_item *target) |
| { |
| struct configfs_subsystem *target_subsys; |
| struct config_group *root, *parent; |
| struct configfs_dirent *subsys_sd; |
| int ret = -ENOENT; |
| |
| /* Disallow this function for configfs root */ |
| if (configfs_is_root(target)) |
| return -EINVAL; |
| |
| parent = target->ci_group; |
| /* |
| * This may happen when someone is trying to depend root |
| * directory of some subsystem |
| */ |
| if (configfs_is_root(&parent->cg_item)) { |
| target_subsys = to_configfs_subsystem(to_config_group(target)); |
| root = parent; |
| } else { |
| target_subsys = parent->cg_subsys; |
| /* Find a cofnigfs root as we may need it for locking */ |
| for (root = parent; !configfs_is_root(&root->cg_item); |
| root = root->cg_item.ci_group) |
| ; |
| } |
| |
| if (target_subsys != caller_subsys) { |
| /* |
| * We are in other configfs subsystem, so we have to do |
| * additional locking to prevent other subsystem from being |
| * unregistered |
| */ |
| inode_lock(d_inode(root->cg_item.ci_dentry)); |
| |
| /* |
| * As we are trying to depend item from other subsystem |
| * we have to check if this subsystem is still registered |
| */ |
| subsys_sd = configfs_find_subsys_dentry( |
| root->cg_item.ci_dentry->d_fsdata, |
| &target_subsys->su_group.cg_item); |
| if (!subsys_sd) |
| goto out_root_unlock; |
| } else { |
| subsys_sd = target_subsys->su_group.cg_item.ci_dentry->d_fsdata; |
| } |
| |
| /* Now we can execute core of depend item */ |
| ret = configfs_do_depend_item(subsys_sd->s_dentry, target); |
| |
| if (target_subsys != caller_subsys) |
| out_root_unlock: |
| /* |
| * We were called from subsystem other than our target so we |
| * took some locks so now it's time to release them |
| */ |
| inode_unlock(d_inode(root->cg_item.ci_dentry)); |
| |
| return ret; |
| } |
| EXPORT_SYMBOL(configfs_depend_item_unlocked); |
| |
| 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; |
| const struct config_item_type *type; |
| struct module *subsys_owner = NULL, *new_item_owner = NULL; |
| struct configfs_fragment *frag; |
| 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; |
| } |
| |
| frag = new_fragment(); |
| if (!frag) { |
| ret = -ENOMEM; |
| 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, frag); |
| else |
| ret = configfs_attach_item(parent_item, item, dentry, frag); |
| |
| 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); |
| put_fragment(frag); |
| |
| 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 configfs_fragment *frag; |
| 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 dentry *wait; |
| |
| 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); |
| 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 */ |
| inode_lock(d_inode(wait)); |
| inode_unlock(d_inode(wait)); |
| dput(wait); |
| } |
| } while (ret == -EAGAIN); |
| |
| frag = sd->s_frag; |
| if (down_write_killable(&frag->frag_sem)) { |
| spin_lock(&configfs_dirent_lock); |
| configfs_detach_rollback(dentry); |
| spin_unlock(&configfs_dirent_lock); |
| return -EINTR; |
| } |
| frag->frag_dead = true; |
| up_write(&frag->frag_sem); |
| |
| /* 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; |
| |
| inode_lock(d_inode(parent)); |
| |
| new_dentry = lookup_one_len(new_name, parent, strlen(new_name)); |
| if (!IS_ERR(new_dentry)) { |
| if (d_really_is_negative(new_dentry)) { |
| 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); |
| } |
| inode_unlock(d_inode(parent)); |
| 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; |
| |
| inode_lock(d_inode(dentry)); |
| /* |
| * 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, NULL); |
| if (IS_ERR(file->private_data)) |
| err = PTR_ERR(file->private_data); |
| else |
| err = 0; |
| } |
| inode_unlock(d_inode(dentry)); |
| |
| 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; |
| |
| inode_lock(d_inode(dentry)); |
| spin_lock(&configfs_dirent_lock); |
| list_del_init(&cursor->s_sibling); |
| spin_unlock(&configfs_dirent_lock); |
| inode_unlock(d_inode(dentry)); |
| |
| 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 *file, struct dir_context *ctx) |
| { |
| struct dentry *dentry = file->f_path.dentry; |
| struct super_block *sb = dentry->d_sb; |
| struct configfs_dirent * parent_sd = dentry->d_fsdata; |
| struct configfs_dirent *cursor = file->private_data; |
| struct list_head *p, *q = &cursor->s_sibling; |
| ino_t ino = 0; |
| |
| if (!dir_emit_dots(file, ctx)) |
| return 0; |
| spin_lock(&configfs_dirent_lock); |
| if (ctx->pos == 2) |
| list_move(q, &parent_sd->s_children); |
| 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; |
| |
| /* |
| * 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. |
| */ |
| dentry = next->s_dentry; |
| if (dentry) |
| inode = d_inode(dentry); |
| if (inode) |
| ino = inode->i_ino; |
| spin_unlock(&configfs_dirent_lock); |
| if (!inode) |
| ino = iunique(sb, 2); |
| |
| name = configfs_get_name(next); |
| len = strlen(name); |
| |
| if (!dir_emit(ctx, name, len, ino, dt_type(next))) |
| return 0; |
| |
| spin_lock(&configfs_dirent_lock); |
| list_move(q, p); |
| p = q; |
| ctx->pos++; |
| } |
| spin_unlock(&configfs_dirent_lock); |
| return 0; |
| } |
| |
| static loff_t configfs_dir_lseek(struct file *file, loff_t offset, int whence) |
| { |
| struct dentry * dentry = file->f_path.dentry; |
| |
| switch (whence) { |
| case 1: |
| offset += file->f_pos; |
| /* fall through */ |
| case 0: |
| if (offset >= 0) |
| break; |
| /* fall through */ |
| default: |
| 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); |
| } |
| } |
| 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, |
| .iterate_shared = configfs_readdir, |
| }; |
| |
| /** |
| * configfs_register_group - creates a parent-child relation between two groups |
| * @parent_group: parent group |
| * @group: child group |
| * |
| * link groups, creates dentry for the child and attaches it to the |
| * parent dentry. |
| * |
| * Return: 0 on success, negative errno code on error |
| */ |
| int configfs_register_group(struct config_group *parent_group, |
| struct config_group *group) |
| { |
| struct configfs_subsystem *subsys = parent_group->cg_subsys; |
| struct dentry *parent; |
| struct configfs_fragment *frag; |
| int ret; |
| |
| frag = new_fragment(); |
| if (!frag) |
| return -ENOMEM; |
| |
| mutex_lock(&subsys->su_mutex); |
| link_group(parent_group, group); |
| mutex_unlock(&subsys->su_mutex); |
| |
| parent = parent_group->cg_item.ci_dentry; |
| |
| inode_lock_nested(d_inode(parent), I_MUTEX_PARENT); |
| ret = create_default_group(parent_group, group, frag); |
| if (ret) |
| goto err_out; |
| |
| spin_lock(&configfs_dirent_lock); |
| configfs_dir_set_ready(group->cg_item.ci_dentry->d_fsdata); |
| spin_unlock(&configfs_dirent_lock); |
| inode_unlock(d_inode(parent)); |
| put_fragment(frag); |
| return 0; |
| err_out: |
| inode_unlock(d_inode(parent)); |
| mutex_lock(&subsys->su_mutex); |
| unlink_group(group); |
| mutex_unlock(&subsys->su_mutex); |
| put_fragment(frag); |
| return ret; |
| } |
| EXPORT_SYMBOL(configfs_register_group); |
| |
| /** |
| * configfs_unregister_group() - unregisters a child group from its parent |
| * @group: parent group to be unregistered |
| * |
| * Undoes configfs_register_group() |
| */ |
| void configfs_unregister_group(struct config_group *group) |
| { |
| struct configfs_subsystem *subsys = group->cg_subsys; |
| struct dentry *dentry = group->cg_item.ci_dentry; |
| struct dentry *parent = group->cg_item.ci_parent->ci_dentry; |
| struct configfs_dirent *sd = dentry->d_fsdata; |
| struct configfs_fragment *frag = sd->s_frag; |
| |
| down_write(&frag->frag_sem); |
| frag->frag_dead = true; |
| up_write(&frag->frag_sem); |
| |
| inode_lock_nested(d_inode(parent), I_MUTEX_PARENT); |
| spin_lock(&configfs_dirent_lock); |
| configfs_detach_prep(dentry, NULL); |
| spin_unlock(&configfs_dirent_lock); |
| |
| configfs_detach_group(&group->cg_item); |
| d_inode(dentry)->i_flags |= S_DEAD; |
| dont_mount(dentry); |
| fsnotify_rmdir(d_inode(parent), dentry); |
| d_delete(dentry); |
| inode_unlock(d_inode(parent)); |
| |
| dput(dentry); |
| |
| mutex_lock(&subsys->su_mutex); |
| unlink_group(group); |
| mutex_unlock(&subsys->su_mutex); |
| } |
| EXPORT_SYMBOL(configfs_unregister_group); |
| |
| /** |
| * configfs_register_default_group() - allocates and registers a child group |
| * @parent_group: parent group |
| * @name: child group name |
| * @item_type: child item type description |
| * |
| * boilerplate to allocate and register a child group with its parent. We need |
| * kzalloc'ed memory because child's default_group is initially empty. |
| * |
| * Return: allocated config group or ERR_PTR() on error |
| */ |
| struct config_group * |
| configfs_register_default_group(struct config_group *parent_group, |
| const char *name, |
| const struct config_item_type *item_type) |
| { |
| int ret; |
| struct config_group *group; |
| |
| group = kzalloc(sizeof(*group), GFP_KERNEL); |
| if (!group) |
| return ERR_PTR(-ENOMEM); |
| config_group_init_type_name(group, name, item_type); |
| |
| ret = configfs_register_group(parent_group, group); |
| if (ret) { |
| kfree(group); |
| return ERR_PTR(ret); |
| } |
| return group; |
| } |
| EXPORT_SYMBOL(configfs_register_default_group); |
| |
| /** |
| * configfs_unregister_default_group() - unregisters and frees a child group |
| * @group: the group to act on |
| */ |
| void configfs_unregister_default_group(struct config_group *group) |
| { |
| configfs_unregister_group(group); |
| kfree(group); |
| } |
| EXPORT_SYMBOL(configfs_unregister_default_group); |
| |
| int configfs_register_subsystem(struct configfs_subsystem *subsys) |
| { |
| int err; |
| struct config_group *group = &subsys->su_group; |
| struct dentry *dentry; |
| struct dentry *root; |
| struct configfs_dirent *sd; |
| struct configfs_fragment *frag; |
| |
| frag = new_fragment(); |
| if (!frag) |
| return -ENOMEM; |
| |
| root = configfs_pin_fs(); |
| if (IS_ERR(root)) { |
| put_fragment(frag); |
| 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); |
| |
| inode_lock_nested(d_inode(root), I_MUTEX_PARENT); |
| |
| err = -ENOMEM; |
| dentry = d_alloc_name(root, group->cg_item.ci_name); |
| if (dentry) { |
| d_add(dentry, NULL); |
| |
| err = configfs_attach_group(sd->s_element, &group->cg_item, |
| dentry, frag); |
| if (err) { |
| BUG_ON(d_inode(dentry)); |
| d_drop(dentry); |
| dput(dentry); |
| } else { |
| spin_lock(&configfs_dirent_lock); |
| configfs_dir_set_ready(dentry->d_fsdata); |
| spin_unlock(&configfs_dirent_lock); |
| } |
| } |
| |
| inode_unlock(d_inode(root)); |
| |
| if (err) { |
| unlink_group(group); |
| configfs_release_fs(); |
| } |
| put_fragment(frag); |
| |
| 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; |
| struct configfs_dirent *sd = dentry->d_fsdata; |
| struct configfs_fragment *frag = sd->s_frag; |
| |
| if (dentry->d_parent != root) { |
| pr_err("Tried to unregister non-subsystem!\n"); |
| return; |
| } |
| |
| down_write(&frag->frag_sem); |
| frag->frag_dead = true; |
| up_write(&frag->frag_sem); |
| |
| inode_lock_nested(d_inode(root), |
| I_MUTEX_PARENT); |
| inode_lock_nested(d_inode(dentry), I_MUTEX_CHILD); |
| mutex_lock(&configfs_symlink_mutex); |
| spin_lock(&configfs_dirent_lock); |
| if (configfs_detach_prep(dentry, NULL)) { |
| pr_err("Tried to unregister non-empty subsystem!\n"); |
| } |
| spin_unlock(&configfs_dirent_lock); |
| mutex_unlock(&configfs_symlink_mutex); |
| configfs_detach_group(&group->cg_item); |
| d_inode(dentry)->i_flags |= S_DEAD; |
| dont_mount(dentry); |
| fsnotify_rmdir(d_inode(root), dentry); |
| inode_unlock(d_inode(dentry)); |
| |
| d_delete(dentry); |
| |
| inode_unlock(d_inode(root)); |
| |
| dput(dentry); |
| |
| unlink_group(group); |
| configfs_release_fs(); |
| } |
| |
| EXPORT_SYMBOL(configfs_register_subsystem); |
| EXPORT_SYMBOL(configfs_unregister_subsystem); |