From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932264AbVH3W77 (ORCPT ); Tue, 30 Aug 2005 18:59:59 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S932266AbVH3W77 (ORCPT ); Tue, 30 Aug 2005 18:59:59 -0400 Received: from smtp.istop.com ([66.11.167.126]:8390 "EHLO smtp.istop.com") by vger.kernel.org with ESMTP id S932264AbVH3W76 (ORCPT ); Tue, 30 Aug 2005 18:59:58 -0400 From: Daniel Phillips To: linux-kernel@vger.kernel.org Subject: [RFC][PATCH 3 of 4] Configfs is really sysfs Date: Wed, 31 Aug 2005 08:59:55 +1000 User-Agent: KMail/1.7.2 Cc: Andrew Morton , Joel Becker , Greg KH References: <200508310854.40482.phillips@istop.com> <200508310857.57617.phillips@istop.com> In-Reply-To: <200508310857.57617.phillips@istop.com> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200508310859.55746.phillips@istop.com> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Configfs rewritten as a single file and updated to use kobjects instead of its own clone of kobjects (config_items). diff -up --recursive 2.6.13-rc5-mm1.clean/fs/configfs/Makefile 2.6.13-rc5-mm1/fs/configfs/Makefile --- 2.6.13-rc5-mm1.clean/fs/configfs/Makefile 2005-08-09 18:23:30.000000000 -0400 +++ 2.6.13-rc5-mm1/fs/configfs/Makefile 2005-08-29 17:26:02.000000000 -0400 @@ -2,6 +2,5 @@ # Makefile for the configfs virtual filesystem # -obj-$(CONFIG_CONFIGFS_FS) += configfs.o +obj-$(CONFIG_CONFIGFS_FS) += configfs.o ddbond.config.o -configfs-objs := inode.o file.o dir.o symlink.o mount.o item.o diff -up --recursive 2.6.13-rc5-mm1.clean/fs/configfs/configfs.c 2.6.13-rc5-mm1/fs/configfs/configfs.c --- 2.6.13-rc5-mm1.clean/fs/configfs/configfs.c 2005-08-30 17:50:30.000000000 -0400 +++ 2.6.13-rc5-mm1/fs/configfs/configfs.c 2005-08-29 21:36:47.000000000 -0400 @@ -0,0 +1,1897 @@ +/* + * Based on sysfs: + * sysfs Copyright (C) 2001, 2002, 2003 Patrick Mochel + * + * configfs Copyright (C) 2005 Oracle. All rights reserved. + */ + +#include +#include +#include +#include +#include +#include +#include + +#define CONFIGFS_ROOT 0x0001 +#define CONFIGFS_DIR 0x0002 +#define CONFIGFS_ITEM_ATTR 0x0004 +#define CONFIGFS_ITEM_LINK 0x0020 +#define CONFIGFS_USET_DIR 0x0040 +#define CONFIGFS_USET_DEFAULT 0x0080 +#define CONFIGFS_USET_DROPPING 0x0100 +#define CONFIGFS_NOT_PINNED (CONFIGFS_ITEM_ATTR) + +struct sysfs_symlink { + struct list_head sl_list; + struct kobject *sl_target; +}; + +static inline struct kobject *to_kobj(struct dentry *dentry) +{ + struct sysfs_dirent *sd = dentry->d_fsdata; + return ((struct kobject *)sd->s_element); +} + +static inline struct attribute *to_attr(struct dentry *dentry) +{ + struct sysfs_dirent *sd = dentry->d_fsdata; + return ((struct attribute *)sd->s_element); +} + +static inline struct kobject *sysfs_get_kobject(struct dentry *dentry) +{ + struct kobject *kobj = NULL; + + spin_lock(&dcache_lock); + if (!d_unhashed(dentry)) { + struct sysfs_dirent *sd = dentry->d_fsdata; + if (sd->s_type & CONFIGFS_ITEM_LINK) { + struct sysfs_symlink *sl = sd->s_element; + kobj = kobject_get(sl->sl_target); + } else + kobj = kobject_get(sd->s_element); + } + spin_unlock(&dcache_lock); + + return kobj; +} + +static kmem_cache_t *sysfs_dir_cachep; + +static void release_sysfs_dirent(struct sysfs_dirent *sd) +{ + if ((sd->s_type & CONFIGFS_ROOT)) + return; + kmem_cache_free(sysfs_dir_cachep, sd); +} + +static struct sysfs_dirent *sysfs_get(struct sysfs_dirent *sd) +{ + if (sd) { + WARN_ON(!atomic_read(&sd->s_count)); + atomic_inc(&sd->s_count); + } + return sd; +} + +static void sysfs_put(struct sysfs_dirent *sd) +{ + WARN_ON(!atomic_read(&sd->s_count)); + if (atomic_dec_and_test(&sd->s_count)) + release_sysfs_dirent(sd); +} + +/* + * inode.c - basic inode and dentry operations. + */ + +static struct super_block *sysfs_sb; + +static struct address_space_operations sysfs_aops = { + .readpage = simple_readpage, + .prepare_write = simple_prepare_write, + .commit_write = simple_commit_write +}; + +static struct backing_dev_info sysfs_backing_dev_info = { + .ra_pages = 0, /* No readahead */ + .capabilities = BDI_CAP_NO_ACCT_DIRTY | BDI_CAP_NO_WRITEBACK, +}; + +static struct inode *sysfs_new_inode(mode_t mode) +{ + struct inode *inode = new_inode(sysfs_sb); + if (inode) { + inode->i_blksize = PAGE_CACHE_SIZE; + inode->i_blocks = 0; + inode->i_mode = mode; + inode->i_uid = 0; + inode->i_gid = 0; + inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME; + inode->i_mapping->a_ops = &sysfs_aops; + inode->i_mapping->backing_dev_info = &sysfs_backing_dev_info; + } + return inode; +} + +static int sysfs_create(struct dentry *dentry, int mode, int (*init) (struct inode *)) +{ + int error = 0; + struct inode *inode = NULL; + if (dentry) { + if (!dentry->d_inode) { + if ((inode = sysfs_new_inode(mode))) { + if (dentry->d_parent + && dentry->d_parent->d_inode) { + struct inode *p_inode = + dentry->d_parent->d_inode; + p_inode->i_mtime = p_inode->i_ctime = + CURRENT_TIME; + } + goto Proceed; + } else + error = -ENOMEM; + } else + error = -EEXIST; + } else + error = -ENOENT; + goto Done; + + Proceed: + if (init) + error = init(inode); + if (!error) { + d_instantiate(dentry, inode); + if (S_ISDIR(mode) || S_ISLNK(mode)) /* pin link and directory dentries */ + dget(dentry); + } else + iput(inode); + Done: + return error; +} + +/* + * Get the name for corresponding element represented by the given sysfs_dirent + */ +static const unsigned char *sysfs_get_name(struct sysfs_dirent *sd) +{ + if (!sd || !sd->s_element) + BUG(); + + /* These always have a dentry, so use that */ + if (sd->s_type & (CONFIGFS_DIR | CONFIGFS_ITEM_LINK)) + return sd->s_dentry->d_name.name; + + if (sd->s_type & CONFIGFS_ITEM_ATTR) + return ((struct attribute *)sd->s_element)->name; + return NULL; +} + +/* + * Unhashes the dentry corresponding to given sysfs_dirent + * Called with parent inode's i_sem held. + */ +static void sysfs_drop_dentry(struct sysfs_dirent *sd, struct dentry *parent) +{ + struct dentry *dentry = sd->s_dentry; + + if (dentry) { + spin_lock(&dcache_lock); + if (!(d_unhashed(dentry) && dentry->d_inode)) { + dget_locked(dentry); + __d_drop(dentry); + spin_unlock(&dcache_lock); + simple_unlink(parent->d_inode, dentry); + } else { + spin_unlock(&dcache_lock); + } + } +} + +#if 0 +static void sysfs_hash_and_remove(struct dentry *dir, const char *name) +{ + struct sysfs_dirent *sd; + struct sysfs_dirent *parent_sd = dir->d_fsdata; + + down(&dir->d_inode->i_sem); + list_for_each_entry(sd, &parent_sd->s_children, s_sibling) { + if (!sd->s_element) + continue; + if (!strcmp(sysfs_get_name(sd), name)) { + list_del_init(&sd->s_sibling); + sysfs_drop_dentry(sd, dir); + sysfs_put(sd); + break; + } + } + up(&dir->d_inode->i_sem); +} +#endif + +static struct kset sysfs_root_group = { + .kobj = { + .name = "root", + .k_name = sysfs_root_group.kobj.name, + }, +}; + +static int is_root(struct kobject *kobj) +{ + return kobj == &sysfs_root_group.kobj; +} + +/* + * symlink.c - operations for sysfs symlinks. + */ + +static int object_depth(struct kobject *kobj) +{ + struct kobject *p = kobj; + int depth = 0; + do { + depth++; + } while ((p = p->parent) && !is_root(p)); + return depth; +} + +static int object_path_length(struct kobject *kobj) +{ + struct kobject *p = kobj; + int length = 1; + do { + length += strlen(kobject_name(p)) + 1; + p = p->parent; + } while (p && !is_root(p)); + return length; +} + +static void fill_object_path(struct kobject *kobj, char *buffer, int length) +{ + struct kobject *p; + + --length; + for (p = kobj; p && !is_root(p); p = p->parent) { + int cur = strlen(kobject_name(p)); + + /* back up enough to print this bus id with '/' */ + length -= cur; + strncpy(buffer + length, kobject_name(p), cur); + *(buffer + --length) = '/'; + } +} + +static int sysfs_get_target_path(struct kobject *kobj, struct kobject *target, char *path) +{ + char *s; + int depth, size; + + depth = object_depth(kobj); + size = object_path_length(target) + depth * 3 - 1; + if (size > PATH_MAX) + return -ENAMETOOLONG; + + pr_debug("%s: depth = %d, size = %d\n", __FUNCTION__, depth, size); + + for (s = path; depth--; s += 3) + strcpy(s, "../"); + + fill_object_path(target, path, size); + pr_debug("%s: path = '%s'\n", __FUNCTION__, path); + + return 0; +} + +static DECLARE_RWSEM(sysfs_rename_sem); + +static int sysfs_getlink(struct dentry *dentry, char *path) +{ + struct kobject *kobj, *sl_target; + int error = 0; + + kobj = sysfs_get_kobject(dentry->d_parent); + if (!kobj) + return -EINVAL; + + sl_target = sysfs_get_kobject(dentry); + if (!sl_target) { + kobject_put(kobj); + return -EINVAL; + } + + down_read(&sysfs_rename_sem); + error = sysfs_get_target_path(kobj, sl_target, path); + up_read(&sysfs_rename_sem); + + kobject_put(kobj); + kobject_put(sl_target); + return error; + +} + +static int sysfs_follow_link(struct dentry *dentry, struct nameidata *nd) +{ + int error = -ENOMEM; + unsigned long page = get_zeroed_page(GFP_KERNEL); + if (page) + error = sysfs_getlink(dentry, (char *)page); + nd_set_link(nd, error ? ERR_PTR(error) : (char *)page); + return 0; +} + +static void sysfs_put_link(struct dentry *dentry, struct nameidata *nd) +{ + char *page = nd_get_link(nd); + if (!IS_ERR(page)) + free_page((unsigned long)page); +} + +static struct inode_operations sysfs_symlink_inode_operations = { + .readlink = generic_readlink, + .follow_link = sysfs_follow_link, + .put_link = sysfs_put_link, +}; + +static int init_symlink(struct inode *inode) +{ + inode->i_op = &sysfs_symlink_inode_operations; + return 0; +} + +/* + * file.c - operations for regular (text) files. + */ + +struct sysfs_buffer { + size_t count; + loff_t pos; + char *page; + struct sysfs_ops *ops; + struct semaphore sem; + int needs_read_fill; +}; + +/* + * Allocate @buffer->page, if it hasn't been already, then call the + * kobject's show() method to fill the buffer with this attribute's + * data. This is called only once, on the file's first read. + */ +static int fill_read_buffer(struct dentry *dentry, struct sysfs_buffer *buffer) +{ + struct attribute *attr = to_attr(dentry); + struct kobject *kobj = to_kobj(dentry->d_parent); + struct sysfs_ops *ops = buffer->ops; + int ret = 0; + ssize_t count; + + if (!buffer->page) + buffer->page = (char *)get_zeroed_page(GFP_KERNEL); + if (!buffer->page) + return -ENOMEM; + + count = ops->show(kobj, attr, buffer->page); + buffer->needs_read_fill = 0; + BUG_ON(count > (ssize_t) PAGE_SIZE); + if (count >= 0) + buffer->count = count; + else + ret = count; + return ret; +} + +/* + * Copy the buffer we filled in fill_read_buffer() to userspace. + * This is done at the reader's leisure, copying and advancing + * the amount they specify each time. + * This may be called continuously until the buffer is empty. + */ +static int flush_read_buffer(struct sysfs_buffer *buffer, char __user *buf, + size_t count, loff_t *ppos) +{ + int error; + + if (*ppos > buffer->count) + return 0; + + if (count > (buffer->count - *ppos)) + count = buffer->count - *ppos; + + error = copy_to_user(buf, buffer->page + *ppos, count); + if (!error) + *ppos += count; + return error ? -EFAULT : count; +} + +/* + * Allocate @buffer->page if it hasn't been already, then + * copy the user-supplied buffer into it. + */ +static int fill_write_buffer(struct sysfs_buffer *buffer, const char __user *buf, + size_t count) +{ + int error; + + if (!buffer->page) + buffer->page = (char *)get_zeroed_page(GFP_KERNEL); + if (!buffer->page) + return -ENOMEM; + + if (count > PAGE_SIZE) + count = PAGE_SIZE; + error = copy_from_user(buffer->page, buf, count); + buffer->needs_read_fill = 1; + return error ? -EFAULT : count; +} + +/* + * Get the correct pointers for the kobject and the attribute we're + * dealing with, then call the store method for the attribute, + * passing the buffer that we acquired in fill_write_buffer(). + */ +static int flush_write_buffer(struct dentry *dentry, struct sysfs_buffer *buffer, + size_t count) +{ + struct attribute *attr = to_attr(dentry); + struct kobject *kobj = to_kobj(dentry->d_parent); + struct sysfs_ops *ops = buffer->ops; + + return ops->store(kobj, attr, buffer->page, count); +} + +static int check_perm(struct inode *inode, struct file *file) +{ + struct kobject *kobj = sysfs_get_kobject(file->f_dentry->d_parent); + struct attribute *attr = to_attr(file->f_dentry); + struct sysfs_buffer *buffer; + struct sysfs_ops *ops = NULL; + int error = 0; + + if (!kobj || !attr) + goto Einval; + + /* Grab the module reference for this attribute if we have one */ + if (!try_module_get(attr->owner)) { + error = -ENODEV; + goto Done; + } + + if (!kobj->ktype) + goto Eaccess; + + ops = kobj->ktype->sysfs_ops; + + /* File needs write support. + * The inode's perms must say it's ok, and we must have a store method. + */ + if (file->f_mode & FMODE_WRITE) { + + if (!(inode->i_mode & S_IWUGO) || !ops->store) + goto Eaccess; + + } + + /* File needs read support. + * The inode's perms must say it's ok, and we there + * must be a show method for it. + */ + if (file->f_mode & FMODE_READ) { + if (!(inode->i_mode & S_IRUGO) || !ops->show) + goto Eaccess; + } + + /* No error? Great, allocate a buffer for the file, and store it + * it in file->private_data for easy access. + */ + buffer = kmalloc(sizeof(struct sysfs_buffer), GFP_KERNEL); + if (buffer) { + memset(buffer, 0, sizeof(struct sysfs_buffer)); + init_MUTEX(&buffer->sem); + buffer->needs_read_fill = 1; + buffer->ops = ops; + file->private_data = buffer; + } else + error = -ENOMEM; + goto Done; + + Einval: + error = -EINVAL; + goto Done; + Eaccess: + error = -EACCES; + module_put(attr->owner); + Done: + if (error && kobj) + kobject_put(kobj); + return error; +} + +/* + * Userspace wants to read an attribute file. The attribute descriptor + * is in the file's ->d_fsdata. The target object is in the directory's + * ->d_fsdata. + * + * We call fill_read_buffer() to allocate and fill the buffer from the + * object's show() method exactly once (if the read is happening from + * the beginning of the file). That should fill the entire buffer with + * all the data the object has to offer for that attribute. + * We then call flush_read_buffer() to copy the buffer to userspace + * in the increments specified. + */ +static ssize_t sysfs_read_file(struct file *file, char __user *buf, + size_t count, loff_t *ppos) +{ + struct sysfs_buffer *buffer = file->private_data; + ssize_t retval = 0; + + down(&buffer->sem); + if (buffer->needs_read_fill) { + if ((retval = fill_read_buffer(file->f_dentry, buffer))) + goto out; + } + pr_debug("%s: count = %d, ppos = %lld, buf = %s\n", + __FUNCTION__, count, *ppos, buffer->page); + retval = flush_read_buffer(buffer, buf, count, ppos); + out: + up(&buffer->sem); + return retval; +} + +/* + * Similar to sysfs_read_file(), though working in the opposite direction. + * We allocate and fill the data from the user in fill_write_buffer(), + * then push it to the kobject in flush_write_buffer(). + * There is no easy way for us to know if userspace is only doing a partial + * write, so we don't support them. We expect the entire buffer to come + * on the first write. + * Hint: if you're writing a value, first read the file, modify only the + * the value you're changing, then write entire buffer back. + */ +static ssize_t sysfs_write_file(struct file *file, const char __user *buf, + size_t count, loff_t *ppos) +{ + struct sysfs_buffer *buffer = file->private_data; + + down(&buffer->sem); + count = fill_write_buffer(buffer, buf, count); + if (count > 0) + count = flush_write_buffer(file->f_dentry, buffer, count); + if (count > 0) + *ppos += count; + up(&buffer->sem); + return count; +} + +static int sysfs_open_file(struct inode *inode, struct file *filp) +{ + return check_perm(inode, filp); +} + +static int sysfs_release(struct inode *inode, struct file *filp) +{ + struct kobject *kobj = to_kobj(filp->f_dentry->d_parent); + struct attribute *attr = to_attr(filp->f_dentry); + struct module *owner = attr->owner; + struct sysfs_buffer *buffer = filp->private_data; + + if (kobj) + kobject_put(kobj); + /* After this point, attr should not be accessed. */ + module_put(owner); + + if (buffer) { + if (buffer->page) + free_page((unsigned long)buffer->page); + kfree(buffer); + } + return 0; +} + +static struct file_operations sysfs_file_operations = { + .read = sysfs_read_file, + .write = sysfs_write_file, + .llseek = generic_file_llseek, + .open = sysfs_open_file, + .release = sysfs_release, +}; + +static int init_file(struct inode *inode) +{ + inode->i_size = PAGE_SIZE; + inode->i_fop = &sysfs_file_operations; + return 0; +} + +static void sysfs_d_iput(struct dentry *dentry, struct inode *inode) +{ + struct sysfs_dirent *sd = dentry->d_fsdata; + + if (sd) { + BUG_ON(sd->s_dentry != dentry); + sd->s_dentry = NULL; + sysfs_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 sysfs_d_delete(struct dentry *dentry) +{ + return 1; +} + +static struct dentry_operations sysfs_dentry_ops = { + .d_iput = sysfs_d_iput, + .d_delete = sysfs_d_delete, +}; + +/* + * Allocates a new sysfs_dirent and links it to the parent sysfs_dirent + */ +static struct sysfs_dirent *sysfs_new_dirent(struct sysfs_dirent *parent_sd, + void *element) +{ + struct sysfs_dirent *sd; + + sd = kmem_cache_alloc(sysfs_dir_cachep, GFP_KERNEL); + if (!sd) + return NULL; + + memset(sd, 0, sizeof(*sd)); + atomic_set(&sd->s_count, 1); + INIT_LIST_HEAD(&sd->s_links); + INIT_LIST_HEAD(&sd->s_children); + list_add(&sd->s_sibling, &parent_sd->s_children); + sd->s_element = element; + + return sd; +} + +static int sysfs_make_dirent(struct sysfs_dirent *parent_sd, struct dentry *dentry, + void *element, umode_t mode, int type) +{ + struct sysfs_dirent *sd; + + sd = sysfs_new_dirent(parent_sd, element); + if (!sd) + return -ENOMEM; + + sd->s_mode = mode; + sd->s_type = type; + sd->s_dentry = dentry; + if (dentry) { + dentry->d_fsdata = sysfs_get(sd); + dentry->d_op = &sysfs_dentry_ops; + } + + return 0; +} + +static int sysfs_add_file(struct dentry *dir, const struct attribute *attr, int type) +{ + struct sysfs_dirent *parent_sd = dir->d_fsdata; + umode_t mode = (attr->mode & S_IALLUGO) | S_IFREG; + int error = 0; + + down(&dir->d_inode->i_sem); + error = sysfs_make_dirent(parent_sd, NULL, (void *)attr, mode, type); + up(&dir->d_inode->i_sem); + + return error; +} + +static int configfs_create_file(struct kobject *kobj, const struct attribute *attr) +{ + BUG_ON(!kobj || !kobj->dentry || !attr); + + return sysfs_add_file(kobj->dentry, attr, CONFIGFS_ITEM_ATTR); +} + +static int configfs_add_link(struct sysfs_symlink *sl, struct dentry *parent, struct dentry *dentry) +{ + int err = 0; + umode_t mode = S_IFLNK | S_IRWXUGO; + + err = sysfs_create(dentry, mode, init_symlink); + if (!err) { + err = sysfs_make_dirent(parent->d_fsdata, dentry, sl, + mode, CONFIGFS_ITEM_LINK); + if (!err) + dentry->d_op = &sysfs_dentry_ops; + } + return err; +} + +static int create_link(struct kobject *parent_kobj, struct kobject *kobj, struct dentry *dentry) +{ + struct sysfs_dirent *target_sd = kobj->dentry->d_fsdata; + struct sysfs_symlink *sl; + int ret; + + ret = -ENOMEM; + sl = kmalloc(sizeof(struct sysfs_symlink), GFP_KERNEL); + if (sl) { + sl->sl_target = kobject_get(kobj); + /* FIXME: needs a lock, I'd bet */ + list_add(&sl->sl_list, &target_sd->s_links); + ret = configfs_add_link(sl, parent_kobj->dentry, dentry); + if (ret) { + list_del_init(&sl->sl_list); + kobject_put(kobj); + kfree(sl); + } + } + + return ret; +} + +static int get_target(const char *symname, struct nameidata *nd, struct kobject **target) +{ + int ret; + + ret = path_lookup(symname, LOOKUP_FOLLOW | LOOKUP_DIRECTORY, nd); + if (!ret) { + if (nd->dentry->d_sb == sysfs_sb) { + *target = sysfs_get_kobject(nd->dentry); + if (!*target) { + ret = -ENOENT; + path_release(nd); + } + } else + ret = -EPERM; + } + + return ret; +} + +/* + * dir.c - Operations for directories. + */ + +static int sysfs_dir_open(struct inode *inode, struct file *file) +{ + struct dentry *dentry = file->f_dentry; + struct sysfs_dirent *parent_sd = dentry->d_fsdata; + + down(&dentry->d_inode->i_sem); + file->private_data = sysfs_new_dirent(parent_sd, NULL); + up(&dentry->d_inode->i_sem); + + return file->private_data ? 0 : -ENOMEM; +} + +static int sysfs_dir_close(struct inode *inode, struct file *file) +{ + struct dentry *dentry = file->f_dentry; + struct sysfs_dirent *cursor = file->private_data; + + down(&dentry->d_inode->i_sem); + list_del_init(&cursor->s_sibling); + up(&dentry->d_inode->i_sem); + + release_sysfs_dirent(cursor); + + return 0; +} + +/* Relationship between s_mode and the DT_xxx types */ +static inline unsigned char dt_type(struct sysfs_dirent *sd) +{ + return (sd->s_mode >> 12) & 15; +} + +static int sysfs_readdir(struct file *filp, void *dirent, filldir_t filldir) +{ + struct dentry *dentry = filp->f_dentry; + struct sysfs_dirent *parent_sd = dentry->d_fsdata; + struct sysfs_dirent *cursor = filp->private_data; + struct list_head *p, *q = &cursor->s_sibling; + ino_t ino; + 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) { + list_del(q); + list_add(q, &parent_sd->s_children); + } + for (p = q->next; p != &parent_sd->s_children; p = p->next) { + struct sysfs_dirent *next; + const char *name; + int len; + + next = list_entry(p, struct sysfs_dirent, s_sibling); + if (!next->s_element) + continue; + + name = sysfs_get_name(next); + len = strlen(name); + if (next->s_dentry) + ino = next->s_dentry->d_inode->i_ino; + else + ino = iunique(sysfs_sb, 2); + + if (filldir(dirent, name, len, filp->f_pos, ino, + dt_type(next)) < 0) + return 0; + + list_del(q); + list_add(q, p); + p = q; + filp->f_pos++; + } + } + return 0; +} + +static loff_t sysfs_dir_lseek(struct file *file, loff_t offset, int origin) +{ + struct dentry *dentry = file->f_dentry; + + down(&dentry->d_inode->i_sem); + switch (origin) { + case 1: + offset += file->f_pos; + case 0: + if (offset >= 0) + break; + default: + up(&file->f_dentry->d_inode->i_sem); + return -EINVAL; + } + if (offset != file->f_pos) { + file->f_pos = offset; + if (file->f_pos >= 2) { + struct sysfs_dirent *sd = dentry->d_fsdata; + struct sysfs_dirent *cursor = file->private_data; + struct list_head *p; + loff_t n = file->f_pos - 2; + + list_del(&cursor->s_sibling); + p = sd->s_children.next; + while (n && p != &sd->s_children) { + struct sysfs_dirent *next; + next = list_entry(p, struct sysfs_dirent, + s_sibling); + if (next->s_element) + n--; + p = p->next; + } + list_add_tail(&cursor->s_sibling, p); + } + } + up(&dentry->d_inode->i_sem); + return offset; +} + +static struct file_operations sysfs_dir_operations = { + .open = sysfs_dir_open, + .release = sysfs_dir_close, + .llseek = sysfs_dir_lseek, + .read = generic_read_dir, + .readdir = sysfs_readdir, +}; + +/* attaches attribute's sysfs_dirent to the dentry corresponding to the + * attribute file + */ +static int sysfs_attach_attr(struct sysfs_dirent *sd, struct dentry *dentry) +{ + struct attribute *attr = sd->s_element; + int error; + + error = sysfs_create(dentry, (attr->mode & S_IALLUGO) | S_IFREG, init_file); + if (error) + return error; + + dentry->d_op = &sysfs_dentry_ops; + dentry->d_fsdata = sysfs_get(sd); + sd->s_dentry = dentry; + d_rehash(dentry); + + return 0; +} + +static struct dentry *sysfs_lookup(struct inode *dir, struct dentry *dentry, + struct nameidata *nd) +{ + struct sysfs_dirent *parent_sd = dentry->d_parent->d_fsdata; + struct sysfs_dirent *sd; + int found = 0; + int err = 0; + + list_for_each_entry(sd, &parent_sd->s_children, s_sibling) { + if (sd->s_type & CONFIGFS_NOT_PINNED) { + const unsigned char *name = sysfs_get_name(sd); + + if (strcmp(name, dentry->d_name.name)) + continue; + + found = 1; + err = sysfs_attach_attr(sd, dentry); + break; + } + } + + if (!found) { + /* + * If it doesn't exist and it isn't a NOT_PINNED item, + * it must be negative. + */ + return simple_lookup(dir, dentry, nd); + } + + return ERR_PTR(err); +} + +static struct inode_operations sysfs_dir_inode_operations; + +static int init_dir(struct inode *inode) +{ + inode->i_op = &sysfs_dir_inode_operations; + inode->i_fop = &sysfs_dir_operations; + + /* directory inodes start off with i_nlink == 2 (for "." entry) */ + inode->i_nlink++; + return 0; +} + +static int create_dir(struct kobject *k, struct dentry *p, struct dentry *d) +{ + int error; + umode_t mode = S_IFDIR | S_IRWXU | S_IRUGO | S_IXUGO; + + error = sysfs_create(d, mode, init_dir); + if (!error) { + error = sysfs_make_dirent(p->d_fsdata, d, k, mode, CONFIGFS_DIR); + if (!error) { + p->d_inode->i_nlink++; + (d)->d_op = &sysfs_dentry_ops; + } + } + return error; +} + +static struct vfsmount *sysfs_mount = NULL; + +static int configfs_create_dir(struct kobject *kobj, struct dentry *dentry) +{ + struct dentry *parent; + int error = 0; + + BUG_ON(!kobj); + + if (kobj->parent) + parent = kobj->parent->dentry; + else if (sysfs_mount && sysfs_mount->mnt_sb) + parent = sysfs_mount->mnt_sb->s_root; + else + return -EFAULT; + + error = create_dir(kobj, parent, dentry); + if (!error) + kobj->dentry = dentry; + return error; +} + +static void remove_dir(struct dentry *d) +{ + struct dentry *parent = dget(d->d_parent); + struct sysfs_dirent *sd; + + sd = d->d_fsdata; + list_del_init(&sd->s_sibling); + sysfs_put(sd); + if (d->d_inode) + simple_rmdir(parent->d_inode, d); + + pr_debug(" o %s removing done (%d)\n", d->d_name.name, atomic_read(&d->d_count)); + + dput(parent); +} + +/* + * sysfs_remove_dir - remove a kobject's directory. + * @kobj: kobject we're removing. + * + * The only thing special about this is that we remove any files in + * the directory before we remove the directory + */ +static void configfs_remove_dir(struct kobject *kobj) +{ + struct dentry *dentry = dget(kobj->dentry); + + if (!dentry) + return; + + remove_dir(dentry); + /* Drop reference from dget() on entrance. */ + dput(dentry); +} + +#if 0 +int sysfs_rename_dir(struct kobject *kobj, const char *new_name) +{ + int error = 0; + struct dentry *new_dentry, *parent; + + if (!strcmp(kobject_name(kobj), new_name)) + return -EINVAL; + + if (!kobj->parent) + return -EINVAL; + + down_write(&sysfs_rename_sem); + parent = kobj->parent->dentry; + + down(&parent->d_inode->i_sem); + + new_dentry = lookup_one_len(new_name, parent, strlen(new_name)); + if (!IS_ERR(new_dentry)) { + if (!new_dentry->d_inode) { + error = kobject_set_name(kobj, "%s", new_name); + if (!error) { + d_add(new_dentry, NULL); + d_move(kobj->dentry, new_dentry); + } else + d_delete(new_dentry); + } else + error = -EEXIST; + dput(new_dentry); + } + up(&parent->d_inode->i_sem); + up_write(&sysfs_rename_sem); + + return error; +} +#endif + +/* + * Only subdirectories count here. Files (CONFIGFS_NOT_PINNED) are + * attributes and are removed by rmdir(). We recurse, taking i_sem + * on all children that are candidates for default detach. If the + * result is clean, then sysfs_detach_group() will handle dropping + * i_sem. If there is an error, the caller will clean up the i_sem + * holders via sysfs_detach_rollback(). + */ +static int sysfs_detach_prep(struct dentry *dentry) +{ + struct sysfs_dirent *parent_sd = dentry->d_fsdata; + struct sysfs_dirent *sd; + int ret = 0; + + if (!list_empty(&parent_sd->s_links)) + return -EBUSY; + + list_for_each_entry(sd, &parent_sd->s_children, s_sibling) { + if (sd->s_type & CONFIGFS_NOT_PINNED) + continue; + if (sd->s_type & CONFIGFS_USET_DEFAULT) { + down(&sd->s_dentry->d_inode->i_sem); + /* Mark that we've taken i_sem */ + sd->s_type |= CONFIGFS_USET_DROPPING; + + ret = sysfs_detach_prep(sd->s_dentry); + if (!ret) + continue; + } else + ret = -ENOTEMPTY; + break; + } + return ret; +} + +/* + * Walk the tree, dropping i_sem wherever CONFIGFS_USET_DROPPING is + * set. + */ +static void sysfs_detach_rollback(struct dentry *dentry) +{ + struct sysfs_dirent *parent_sd = dentry->d_fsdata; + struct sysfs_dirent *sd; + + list_for_each_entry(sd, &parent_sd->s_children, s_sibling) { + if (sd->s_type & CONFIGFS_USET_DEFAULT) { + sysfs_detach_rollback(sd->s_dentry); + + if (sd->s_type & CONFIGFS_USET_DROPPING) { + sd->s_type &= ~CONFIGFS_USET_DROPPING; + up(&sd->s_dentry->d_inode->i_sem); + } + } + } +} + +static void detach_attrs(struct kobject *kobj) +{ + struct dentry *dentry = dget(kobj->dentry); + struct sysfs_dirent *parent_sd; + struct sysfs_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; + list_del_init(&sd->s_sibling); + sysfs_drop_dentry(sd, dentry); + sysfs_put(sd); + } + + /* Drop reference from dget() on entrance. */ + dput(dentry); +} + +/* + * All of link_obj/unlink_obj/link_group/unlink_group require that + * subsys->su_sem is held. + */ + +static void sysfs_detach_group(struct kobject *kobj); + +static void detach_groups(struct kset *group) +{ + struct dentry *dentry = dget(group->kobj.dentry); + struct dentry *child; + struct sysfs_dirent *parent_sd; + struct sysfs_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; + + sysfs_detach_group(sd->s_element); + child->d_inode->i_flags |= S_DEAD; + + /* + * From rmdir/unregister, a sysfs_detach_prep() pass + * has taken our i_sem for us. Drop it. + * From mkdir/register cleanup, there is no sem held. + */ + if (sd->s_type & CONFIGFS_USET_DROPPING) + up(&child->d_inode->i_sem); + + d_delete(child); + dput(child); + } + + /** + * Drop reference from dget() on entrance. + */ + dput(dentry); +} + +static void sysfs_detach_item(struct kobject *kobj) +{ + detach_attrs(kobj); + configfs_remove_dir(kobj); +} + +static void unlink_obj(struct kobject *kobj) +{ + struct kset *group; + + group = kobj->kset; + if (group) { + list_del_init(&kobj->entry); + + kobj->kset = NULL; + kobj->parent = NULL; + kobject_put(kobj); + + config_group_put(group); + } +} + +static void unlink_group(struct kset *group) +{ + int i; + struct kset *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->subsys = NULL; + unlink_obj(&group->kobj); +} + +static void sysfs_detach_group(struct kobject *kobj) +{ + detach_groups(to_config_group(kobj)); + sysfs_detach_item(kobj); +} + +/* + * 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 type. + */ +static void client_drop_item(struct kobject *parent_kobj, struct kobject *kobj) +{ + struct kobj_type *type; + + type = parent_kobj->ktype; + BUG_ON(!type); + + if (type->ct_group_ops && type->ct_group_ops->drop_item) + type->ct_group_ops->drop_item(to_config_group(parent_kobj), kobj); + else + kobject_put(kobj); +} + +static int sysfs_attach_group(struct kobject *parent_kobj, struct kobject *kobj, struct dentry *dentry); + +static int populate_attrs(struct kobject *kobj) +{ + struct kobj_type *t = kobj->ktype; + struct attribute *attr; + int error = 0; + int i; + + if (!t) + return -EINVAL; + if (t->default_attrs) { + for (i = 0; (attr = t->default_attrs[i]) != NULL; i++) { + if ((error = configfs_create_file(kobj, attr))) + break; + } + } + + if (error) + detach_attrs(kobj); + + return error; +} + +/* + * The goal is that sysfs_attach_item() (and + * sysfs_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. + * + * sysfs_detach_group() and sysfs_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 sysfs_attach_item(struct kobject *parent_kobj, struct kobject *kobj, struct dentry *dentry) +{ + int ret; + + ret = configfs_create_dir(kobj, dentry); + if (!ret) { + ret = populate_attrs(kobj); + if (ret) { + configfs_remove_dir(kobj); + d_delete(dentry); + } + } + return ret; +} + +/* + * 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 kset *parent_group, struct kset *group) +{ + int ret; + struct qstr name; + struct sysfs_dirent *sd; + /* We trust the caller holds a reference to parent */ + struct dentry *child, *parent = parent_group->kobj.dentry; + + if (!group->kobj.k_name) + group->kobj.k_name = group->kobj.name; + name.name = group->kobj.k_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 = sysfs_attach_group(&parent_group->kobj, + &group->kobj, child); + if (!ret) { + sd = child->d_fsdata; + sd->s_type |= CONFIGFS_USET_DEFAULT; + } else { + d_delete(child); + dput(child); + } + } + return ret; +} + +static int populate_groups(struct kset *group) +{ + struct kset *new_group; + struct dentry *dentry = group->kobj.dentry; + int ret = 0; + int i; + + if (group && group->default_groups) { + /* FYI, we're faking mkdir here + * I'm not sure we need this semaphore, as we're called + * from our parent's mkdir. That holds our parent's + * i_sem, so afaik lookup cannot continue through our + * parent to find us, let alone mess with our tree. + * That said, taking our i_sem is closer to mkdir + * emulation, and shouldn't hurt. */ + down(&dentry->d_inode->i_sem); + + for (i = 0; group->default_groups[i]; i++) { + new_group = group->default_groups[i]; + + ret = create_default_group(group, new_group); + if (ret) + break; + } + + up(&dentry->d_inode->i_sem); + } + + if (ret) + detach_groups(group); + return ret; +} + +static int sysfs_attach_group(struct kobject *parent_kobj, struct kobject *kobj, struct dentry *dentry) +{ + int ret; + struct sysfs_dirent *sd; + + ret = sysfs_attach_item(parent_kobj, kobj, dentry); + if (!ret) { + sd = dentry->d_fsdata; + sd->s_type |= CONFIGFS_USET_DIR; + + ret = populate_groups(to_config_group(kobj)); + if (ret) { + sysfs_detach_item(kobj); + d_delete(dentry); + } + } + return ret; +} + +static void link_obj(struct kobject *parent_kobj, struct kobject *kobj) +{ + /* Parent seems redundant with group, but it makes certain + * traversals much nicer. */ + kobj->parent = parent_kobj; + kobj->kset = config_group_get(to_config_group(parent_kobj)); + list_add_tail(&kobj->entry, &kobj->kset->cg_children); + + kobject_get(kobj); +} + +static void link_group(struct kset *parent_group, struct kset *group) +{ + int i; + struct kset *new_group; + struct subsystem *subsys = NULL; /* gcc is a turd */ + + link_obj(&parent_group->kobj, &group->kobj); + + if (parent_group->subsys) + subsys = parent_group->subsys; + else if (is_root(&parent_group->kobj)) + subsys = to_configfs_subsystem(group); + else + BUG(); + group->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); + } + } +} + +static int sysfs_mkdir(struct inode *dir, struct dentry *dentry, int mode) +{ + int ret; + struct kset *group; + struct kobject *kobj; + struct kobject *parent_kobj; + struct subsystem *subsys; + struct sysfs_dirent *sd; + struct kobj_type *type; + struct module *owner; + char *name; + + if (dentry->d_parent == sysfs_sb->s_root) + return -EPERM; + + sd = dentry->d_parent->d_fsdata; + if (!(sd->s_type & CONFIGFS_USET_DIR)) + return -EPERM; + + parent_kobj = sysfs_get_kobject(dentry->d_parent); + type = parent_kobj->ktype; + subsys = to_config_group(parent_kobj)->subsys; + BUG_ON(!subsys); + + if (!type || !type->ct_group_ops || + (!type->ct_group_ops->make_group && + !type->ct_group_ops->make_item)) { + kobject_put(parent_kobj); + return -EPERM; /* What lack-of-mkdir returns */ + } + + name = kmalloc(dentry->d_name.len + 1, GFP_KERNEL); + if (!name) { + kobject_put(parent_kobj); + return -ENOMEM; + } + snprintf(name, dentry->d_name.len + 1, "%s", dentry->d_name.name); + + down_write(&subsys->rwsem); + group = NULL; + kobj = NULL; + if (type->ct_group_ops->make_group) { + group = type->ct_group_ops->make_group(to_config_group(parent_kobj), name); + if (group) { + link_group(to_config_group(parent_kobj), group); + kobj = &group->kobj; + } + } else { + kobj = type->ct_group_ops->make_item(to_config_group(parent_kobj), name); + if (kobj) + link_obj(parent_kobj, kobj); + } + up_write(&subsys->rwsem); + + kfree(name); + if (!kobj) { + kobject_put(parent_kobj); + return -ENOMEM; + } + + ret = -EINVAL; + type = kobj->ktype; + if (type) { + owner = type->ct_owner; + if (try_module_get(owner)) { + ret = group ? + sysfs_attach_group(parent_kobj, kobj, dentry) : + sysfs_attach_item(parent_kobj, kobj, dentry); + + if (ret) { + down_write(&subsys->rwsem); + if (group) + unlink_group(group); + else + unlink_obj(kobj); + client_drop_item(parent_kobj, kobj); + up_write(&subsys->rwsem); + + kobject_put(parent_kobj); + module_put(owner); + } + } + } + + return ret; +} + +static int sysfs_rmdir(struct inode *dir, struct dentry *dentry) +{ + struct kobject *parent_kobj; + struct kobject *kobj; + struct subsystem *subsys; + struct sysfs_dirent *sd; + struct module *owner = NULL; + int ret; + + if (dentry->d_parent == sysfs_sb->s_root) + return -EPERM; + + sd = dentry->d_fsdata; + if (sd->s_type & CONFIGFS_USET_DEFAULT) + return -EPERM; + + parent_kobj = sysfs_get_kobject(dentry->d_parent); + subsys = to_config_group(parent_kobj)->subsys; + BUG_ON(!subsys); + + if (!parent_kobj->ktype) { + kobject_put(parent_kobj); + return -EINVAL; + } + + ret = sysfs_detach_prep(dentry); + if (ret) { + sysfs_detach_rollback(dentry); + kobject_put(parent_kobj); + return ret; + } + + kobj = sysfs_get_kobject(dentry); + + /* Drop reference from above, item already holds one. */ + kobject_put(parent_kobj); + + if (kobj->ktype) + owner = kobj->ktype->ct_owner; + + if (sd->s_type & CONFIGFS_USET_DIR) { + sysfs_detach_group(kobj); + + down_write(&subsys->rwsem); + unlink_group(to_config_group(kobj)); + } else { + sysfs_detach_item(kobj); + + down_write(&subsys->rwsem); + unlink_obj(kobj); + } + + client_drop_item(parent_kobj, kobj); + up_write(&subsys->rwsem); + + /* Drop our reference from above */ + kobject_put(kobj); + + module_put(owner); + + return 0; +} + +int sysfs_symlink(struct inode *dir, struct dentry *dentry, const char *symname) +{ + int ret; + struct nameidata nd; + struct kobject *parent_kobj; + struct kobject *sl_target; + struct kobj_type *type; + + ret = -EPERM; /* What lack-of-symlink returns */ + if (dentry->d_parent == sysfs_sb->s_root) + goto out; + + parent_kobj = sysfs_get_kobject(dentry->d_parent); + type = parent_kobj->ktype; + + if (!type || !type->sysfs_ops || !type->sysfs_ops->allow_link) + goto out_put; + + ret = get_target(symname, &nd, &sl_target); + if (ret) + goto out_put; + + ret = type->sysfs_ops->allow_link(parent_kobj, sl_target); + if (!ret) + ret = create_link(parent_kobj, sl_target, dentry); + + kobject_put(sl_target); + path_release(&nd); + + out_put: + kobject_put(parent_kobj); + + out: + return ret; +} + +static int sysfs_unlink(struct inode *dir, struct dentry *dentry) +{ + struct sysfs_dirent *sd = dentry->d_fsdata; + struct sysfs_symlink *sl; + struct kobject *parent_kobj; + struct kobj_type *type; + int ret; + + ret = -EPERM; /* What lack-of-symlink returns */ + if (!(sd->s_type & CONFIGFS_ITEM_LINK)) + goto out; + + if (dentry->d_parent == sysfs_sb->s_root) + BUG(); + + sl = sd->s_element; + + parent_kobj = sysfs_get_kobject(dentry->d_parent); + type = parent_kobj->ktype; + + list_del_init(&sd->s_sibling); + sysfs_drop_dentry(sd, dentry->d_parent); + dput(dentry); + sysfs_put(sd); + + /* + * drop_link() must be called before + * list_del_init(&sl->sl_list), so that the order of + * drop_link(this, target) and drop_item(target) is preserved. + */ + if (type && type->sysfs_ops && type->sysfs_ops->drop_link) + type->sysfs_ops->drop_link(parent_kobj, sl->sl_target); + + /* FIXME: Needs lock */ + list_del_init(&sl->sl_list); + + /* Put reference from create_link() */ + kobject_put(sl->sl_target); + kfree(sl); + + kobject_put(parent_kobj); + + ret = 0; + + out: + return ret; +} + +static struct inode_operations sysfs_dir_inode_operations = { + .lookup = sysfs_lookup, + .mkdir = sysfs_mkdir, + .rmdir = sysfs_rmdir, + .symlink = sysfs_symlink, + .unlink = sysfs_unlink, +}; + +static int sysfs_mnt_count = 0; + +int sysfs_pin_fs(void) +{ + return simple_pin_fs("configfs", &sysfs_mount, &sysfs_mnt_count); +} + +void sysfs_release_fs(void) +{ + simple_release_fs(&sysfs_mount, &sysfs_mnt_count); +} + +int configfs_register_subsystem(struct subsystem *subsys) +{ + int err; + struct kset *group = &subsys->kset; + struct qstr name; + struct dentry *dentry; + struct sysfs_dirent *sd; + + err = sysfs_pin_fs(); + if (err) + return err; + + if (!group->kobj.k_name) + group->kobj.k_name = group->kobj.name; + + sd = sysfs_sb->s_root->d_fsdata; + link_group(to_config_group(sd->s_element), group); + + down(&sysfs_sb->s_root->d_inode->i_sem); + + name.name = group->kobj.k_name; + name.len = strlen(name.name); + name.hash = full_name_hash(name.name, name.len); + + err = -ENOMEM; + dentry = d_alloc(sysfs_sb->s_root, &name); + if (!dentry) + goto out_release; + + d_add(dentry, NULL); + + err = sysfs_attach_group(sd->s_element, &group->kobj, dentry); + if (!err) + dentry = NULL; + else + d_delete(dentry); + + up(&sysfs_sb->s_root->d_inode->i_sem); + + if (dentry) { + dput(dentry); + out_release: + unlink_group(group); + sysfs_release_fs(); + } + + return err; +} + +void configfs_unregister_subsystem(struct subsystem *subsys) +{ + struct kset *group = &subsys->kset; + struct dentry *dentry = group->kobj.dentry; + + if (dentry->d_parent != sysfs_sb->s_root) { + printk(KERN_ERR + "configfs: Tried to unregister non-subsystem!\n"); + return; + } + + down(&sysfs_sb->s_root->d_inode->i_sem); + down(&dentry->d_inode->i_sem); + if (sysfs_detach_prep(dentry)) { + printk(KERN_ERR + "configfs: Tried to unregister non-empty subsystem!\n"); + } + sysfs_detach_group(&group->kobj); + dentry->d_inode->i_flags |= S_DEAD; + up(&dentry->d_inode->i_sem); + + d_delete(dentry); + + up(&sysfs_sb->s_root->d_inode->i_sem); + + dput(dentry); + + unlink_group(group); + sysfs_release_fs(); +} + +/* + * mount.c - operations for initializing and mounting + */ + +#define CONFIGFS_MAGIC 0x62656570 + +static struct super_operations sysfs_ops = { + .statfs = simple_statfs, + .drop_inode = generic_delete_inode, +}; + +static struct sysfs_dirent sysfs_root = { + .s_sibling = LIST_HEAD_INIT(sysfs_root.s_sibling), + .s_children = LIST_HEAD_INIT(sysfs_root.s_children), + .s_element = &sysfs_root_group.kobj, + .s_type = CONFIGFS_ROOT, +}; + +static int sysfs_fill_super(struct super_block *sb, void *data, int silent) +{ + struct inode *inode; + struct dentry *root; + + sb->s_blocksize = PAGE_CACHE_SIZE; + sb->s_blocksize_bits = PAGE_CACHE_SHIFT; + sb->s_magic = CONFIGFS_MAGIC; + sb->s_op = &sysfs_ops; + sysfs_sb = sb; + + inode = sysfs_new_inode(S_IFDIR | S_IRWXU | S_IRUGO | S_IXUGO); + if (inode) { + inode->i_op = &sysfs_dir_inode_operations; + inode->i_fop = &sysfs_dir_operations; + /* directory inodes start off with i_nlink == 2 (for "." entry) */ + inode->i_nlink++; + } else { + pr_debug("configfs: could not get root inode\n"); + return -ENOMEM; + } + + root = d_alloc_root(inode); + if (!root) { + pr_debug("%s: could not get root dentry!\n", __FUNCTION__); + iput(inode); + return -ENOMEM; + } + config_group_init(&sysfs_root_group); + sysfs_root_group.kobj.dentry = root; + root->d_fsdata = &sysfs_root; + sb->s_root = root; + return 0; +} + +static struct super_block *sysfs_get_sb(struct file_system_type *fs_type, + int flags, const char *dev_name, void *data) +{ + return get_sb_single(fs_type, flags, data, sysfs_fill_super); +} + +static struct file_system_type sysfs_fs_type = { + .name = "configfs", + .owner = THIS_MODULE, + .get_sb = sysfs_get_sb, + .kill_sb = kill_litter_super, +}; + +static int __init sysfs_init(void) +{ + int err = -ENOMEM; + + sysfs_dir_cachep = kmem_cache_create("configfs_dir_cache", + sizeof(struct sysfs_dirent), 0, 0, NULL, NULL); + if (!sysfs_dir_cachep) + goto out; + + err = register_filesystem(&sysfs_fs_type); + if (err) + goto out_err; + out: + return err; + out_err: + kmem_cache_destroy(sysfs_dir_cachep); + sysfs_dir_cachep = NULL; + goto out; +} + +static void __exit sysfs_exit(void) +{ + unregister_filesystem(&sysfs_fs_type); +} + +MODULE_AUTHOR("Oracle"); +MODULE_LICENSE("GPL"); +MODULE_VERSION("0.0.1"); +MODULE_DESCRIPTION + ("Simple RAM filesystem for user driven kernel subsystem configuration."); + +module_init(sysfs_init); +module_exit(sysfs_exit); + +/* + * configfs client helpers + */ + +void config_group_init_type_name(struct kset *group, const char *name, struct kobj_type *type) +{ + kobject_set_name(&group->kobj, name); + group->kobj.ktype = type; + config_group_init(group); +} + +void config_group_init(struct kset *group) +{ + kobject_init(&group->kobj); + INIT_LIST_HEAD(&group->cg_children); +} + +void kobject_init_type_name(struct kobject *kobj, const char *name, struct kobj_type *type) +{ + kobject_set_name(kobj, name); + kobj->ktype = type; + kobject_init(kobj); +} + +EXPORT_SYMBOL(configfs_register_subsystem); +EXPORT_SYMBOL(configfs_unregister_subsystem); +EXPORT_SYMBOL(config_group_init_type_name); +EXPORT_SYMBOL(config_group_init); +EXPORT_SYMBOL(kobject_init_type_name);