diff options
Diffstat (limited to 'fs/configfs/dir.c')
| -rw-r--r-- | fs/configfs/dir.c | 1102 |
1 files changed, 1102 insertions, 0 deletions
diff --git a/fs/configfs/dir.c b/fs/configfs/dir.c new file mode 100644 index 000000000000..e48b539243a1 --- /dev/null +++ b/fs/configfs/dir.c @@ -0,0 +1,1102 @@ +/* -*- mode: c; c-basic-offset: 8; -*- + * vim: noexpandtab sw=8 ts=8 sts=0: + * + * dir.c - Operations for configfs directories. + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public + * License as published by the Free Software Foundation; either + * version 2 of the License, or (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * General Public License for more details. + * + * You should have received a copy of the GNU General Public + * License along with this program; if not, write to the + * Free Software Foundation, Inc., 59 Temple Place - Suite 330, + * Boston, MA 021110-1307, USA. + * + * Based on sysfs: + * sysfs is Copyright (C) 2001, 2002, 2003 Patrick Mochel + * + * configfs Copyright (C) 2005 Oracle. All rights reserved. + */ + +#undef DEBUG + +#include <linux/fs.h> +#include <linux/mount.h> +#include <linux/module.h> +#include <linux/slab.h> + +#include <linux/configfs.h> +#include "configfs_internal.h" + +DECLARE_RWSEM(configfs_rename_sem); + +static void configfs_d_iput(struct dentry * dentry, + struct inode * inode) +{ + struct configfs_dirent * sd = dentry->d_fsdata; + + if (sd) { + BUG_ON(sd->s_dentry != dentry); + sd->s_dentry = NULL; + configfs_put(sd); + } + iput(inode); +} + +/* + * We _must_ delete our dentries on last dput, as the chain-to-parent + * behavior is required to clear the parents of default_groups. + */ +static int configfs_d_delete(struct dentry *dentry) +{ + return 1; +} + +static struct dentry_operations configfs_dentry_ops = { + .d_iput = configfs_d_iput, + /* simple_delete_dentry() isn't exported */ + .d_delete = configfs_d_delete, +}; + +/* + * 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) +{ + struct configfs_dirent * sd; + + sd = kmalloc(sizeof(*sd), 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; +} + +int configfs_make_dirent(struct configfs_dirent * parent_sd, + struct dentry * dentry, void * element, + umode_t mode, int type) +{ + struct configfs_dirent * sd; + + sd = configfs_new_dirent(parent_sd, element); + if (!sd) + return -ENOMEM; + + sd->s_mode = mode; + sd->s_type = type; + sd->s_dentry = dentry; + if (dentry) { + dentry->d_fsdata = configfs_get(sd); + dentry->d_op = &configfs_dentry_ops; + } + + return 0; +} + +static int init_dir(struct inode * inode) +{ + inode->i_op = &configfs_dir_inode_operations; + inode->i_fop = &configfs_dir_operations; + + /* directory inodes start off with i_nlink == 2 (for "." entry) */ + inode->i_nlink++; + return 0; +} + +static int init_file(struct inode * inode) +{ + inode->i_size = PAGE_SIZE; + inode->i_fop = &configfs_file_operations; + return 0; +} + +static int init_symlink(struct inode * inode) +{ + inode->i_op = &configfs_symlink_inode_operations; + return 0; +} + +static int create_dir(struct config_item * k, struct dentry * p, + struct dentry * d) +{ + int error; + umode_t mode = S_IFDIR| S_IRWXU | S_IRUGO | S_IXUGO; + + error = configfs_create(d, mode, init_dir); + if (!error) { + error = configfs_make_dirent(p->d_fsdata, d, k, mode, + CONFIGFS_DIR); + if (!error) { + p->d_inode->i_nlink++; + (d)->d_op = &configfs_dentry_ops; + } + } + return error; +} + + +/** + * configfs_create_dir - create a directory for an config_item. + * @item: config_itemwe're creating directory for. + * @dentry: config_item's dentry. + */ + +static int configfs_create_dir(struct config_item * item, struct dentry *dentry) +{ + struct dentry * parent; + int error = 0; + + BUG_ON(!item); + + if (item->ci_parent) + parent = item->ci_parent->ci_dentry; + else if (configfs_mount && configfs_mount->mnt_sb) + parent = configfs_mount->mnt_sb->s_root; + else + return -EFAULT; + + error = create_dir(item,parent,dentry); + if (!error) + item->ci_dentry = dentry; + return error; +} + +int configfs_create_link(struct configfs_symlink *sl, + struct dentry *parent, + struct dentry *dentry) +{ + int err = 0; + umode_t mode = S_IFLNK | S_IRWXUGO; + + err = configfs_create(dentry, mode, init_symlink); + if (!err) { + err = configfs_make_dirent(parent->d_fsdata, dentry, sl, + mode, CONFIGFS_ITEM_LINK); + if (!err) + dentry->d_op = &configfs_dentry_ops; + } + return err; +} + +static void remove_dir(struct dentry * d) +{ + struct dentry * parent = dget(d->d_parent); + struct configfs_dirent * sd; + + sd = d->d_fsdata; + list_del_init(&sd->s_sibling); + configfs_put(sd); + if (d->d_inode) + simple_rmdir(parent->d_inode,d); + + pr_debug(" o %s removing done (%d)\n",d->d_name.name, + atomic_read(&d->d_count)); + + dput(parent); +} + +/** + * configfs_remove_dir - remove an config_item's directory. + * @item: config_item we're removing. + * + * The only thing special about this is that we remove any files in + * the directory before we remove the directory, and we've inlined + * what used to be configfs_rmdir() below, instead of calling separately. + */ + +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; + + error = configfs_create(dentry, (attr->ca_mode & S_IALLUGO) | S_IFREG, init_file); + if (error) + return error; + + dentry->d_op = &configfs_dentry_ops; + dentry->d_fsdata = configfs_get(sd); + sd->s_dentry = dentry; + d_rehash(dentry); + + return 0; +} + +static struct dentry * configfs_lookup(struct inode *dir, + struct dentry *dentry, + struct nameidata *nd) +{ + struct configfs_dirent * parent_sd = dentry->d_parent->d_fsdata; + struct configfs_dirent * sd; + int found = 0; + int err = 0; + + 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. + */ + return simple_lookup(dir, dentry, nd); + } + + return ERR_PTR(err); +} + +/* + * 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 configfs_detach_group() will handle dropping + * i_sem. If there is an error, the caller will clean up the i_sem + * holders via configfs_detach_rollback(). + */ +static int configfs_detach_prep(struct dentry *dentry) +{ + struct configfs_dirent *parent_sd = dentry->d_fsdata; + struct configfs_dirent *sd; + int ret; + + 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_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 = configfs_detach_prep(sd->s_dentry); + if (!ret) + continue; + } else + ret = -ENOTEMPTY; + + break; + } + +out: + return ret; +} + +/* + * Walk the tree, dropping i_sem wherever CONFIGFS_USET_DROPPING is + * set. + */ +static void configfs_detach_rollback(struct dentry *dentry) +{ + struct configfs_dirent *parent_sd = dentry->d_fsdata; + struct configfs_dirent *sd; + + list_for_each_entry(sd, &parent_sd->s_children, s_sibling) { + if (sd->s_type & CONFIGFS_USET_DEFAULT) { + configfs_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 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; + list_del_init(&sd->s_sibling); + configfs_drop_dentry(sd, dentry); + configfs_put(sd); + } + + /** + * Drop reference from dget() on entrance. + */ + dput(dentry); +} + +static int populate_attrs(struct config_item *item) +{ + struct config_item_type *t = item->ci_type; + struct configfs_attribute *attr; + int error = 0; + int i; + + if (!t) + return -EINVAL; + if (t->ct_attrs) { + for (i = 0; (attr = t->ct_attrs[i]) != NULL; i++) { + if ((error = configfs_create_file(item, attr))) + break; + } + } + + if (error) + detach_attrs(item); + + return error; +} + +static int configfs_attach_group(struct config_item *parent_item, + struct config_item *item, + struct dentry *dentry); +static void configfs_detach_group(struct config_item *item); + +static void detach_groups(struct config_group *group) +{ + struct dentry * dentry = dget(group->cg_item.ci_dentry); + struct dentry *child; + struct configfs_dirent *parent_sd; + struct configfs_dirent *sd, *tmp; + + if (!dentry) + return; + + parent_sd = dentry->d_fsdata; + list_for_each_entry_safe(sd, tmp, &parent_sd->s_children, s_sibling) { + if (!sd->s_element || + !(sd->s_type & CONFIGFS_USET_DEFAULT)) + continue; + + child = sd->s_dentry; + + configfs_detach_group(sd->s_element); + child->d_inode->i_flags |= S_DEAD; + + /* + * From rmdir/unregister, a configfs_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); +} + +/* + * This fakes mkdir(2) on a default_groups[] entry. It + * creates a dentry, attachs it, and then does fixup + * on the sd->s_type. + * + * We could, perhaps, tweak our parent's ->mkdir for a minute and + * try using vfs_mkdir. Just a thought. + */ +static int create_default_group(struct config_group *parent_group, + struct config_group *group) +{ + int ret; + struct qstr name; + struct configfs_dirent *sd; + /* We trust the caller holds a reference to parent */ + struct dentry *child, *parent = parent_group->cg_item.ci_dentry; + + if (!group->cg_item.ci_name) + group->cg_item.ci_name = group->cg_item.ci_namebuf; + name.name = group->cg_item.ci_name; + name.len = strlen(name.name); + name.hash = full_name_hash(name.name, name.len); + + ret = -ENOMEM; + child = d_alloc(parent, &name); + if (child) { + d_add(child, NULL); + + ret = configfs_attach_group(&parent_group->cg_item, + &group->cg_item, child); + if (!ret) { + sd = child->d_fsdata; + sd->s_type |= CONFIGFS_USET_DEFAULT; + } else { + d_delete(child); + dput(child); + } + } + + return ret; +} + +static int populate_groups(struct config_group *group) +{ + struct config_group *new_group; + struct dentry *dentry = group->cg_item.ci_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; +} + +/* + * All of link_obj/unlink_obj/link_group/unlink_group require that + * subsys->su_sem 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; + config_item_put(item); + + 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; + item->ci_group = config_group_get(to_config_group(parent_item)); + list_add_tail(&item->ci_entry, &item->ci_group->cg_children); + + config_item_get(item); +} + +static void unlink_group(struct config_group *group) +{ + int i; + struct config_group *new_group; + + if (group->default_groups) { + for (i = 0; group->default_groups[i]; i++) { + new_group = group->default_groups[i]; + unlink_group(new_group); + } + } + + group->cg_subsys = NULL; + unlink_obj(&group->cg_item); +} + +static void link_group(struct config_group *parent_group, struct config_group *group) +{ + int i; + struct config_group *new_group; + struct configfs_subsystem *subsys = NULL; /* gcc is a turd */ + + link_obj(&parent_group->cg_item, &group->cg_item); + + if (parent_group->cg_subsys) + subsys = parent_group->cg_subsys; + else if (configfs_is_root(&parent_group->cg_item)) + subsys = to_configfs_subsystem(group); + else + BUG(); + group->cg_subsys = subsys; + + if (group->default_groups) { + for (i = 0; group->default_groups[i]; i++) { + new_group = group->default_groups[i]; + link_group(group, new_group); + } + } +} + +/* + * The goal is that configfs_attach_item() (and + * configfs_attach_group()) can be called from either the VFS or this + * module. That is, they assume that the items have been created, + * the dentry allocated, and the dcache is all ready to go. + * + * If they fail, they must clean up after themselves as if they + * had never been called. The caller (VFS or local function) will + * handle cleaning up the dcache bits. + * + * configfs_detach_group() and configfs_detach_item() behave similarly on + * the way out. They assume that the proper semaphores are held, they + * clean up the configfs items, and they expect their callers will + * handle the dcache bits. + */ +static int configfs_attach_item(struct config_item *parent_item, + struct config_item *item, + struct dentry *dentry) +{ + int ret; + + ret = configfs_create_dir(item, dentry); + if (!ret) { + ret = populate_attrs(item); + if (ret) { + configfs_remove_dir(item); + d_delete(dentry); + } + } + + return ret; +} + +static void configfs_detach_item(struct config_item *item) +{ + detach_attrs(item); + configfs_remove_dir(item); +} + +static int configfs_attach_group(struct config_item *parent_item, + struct config_item *item, + struct dentry *dentry) +{ + int ret; + struct configfs_dirent *sd; + + ret = configfs_attach_item(parent_item, item, dentry); + if (!ret) { + sd = dentry->d_fsdata; + sd->s_type |= CONFIGFS_USET_DIR; + + ret = populate_groups(to_config_group(item)); + if (ret) { + configfs_detach_item(item); + d_delete(dentry); + } + } + + return ret; +} + +static void configfs_detach_group(struct config_item *item) +{ + detach_groups(to_config_group(item)); + configfs_detach_item(item); +} + +/* + * Drop the initial reference from make_item()/make_group() + * This function assumes that reference is held on item + * and that item holds a valid reference to the parent. Also, it + * assumes the caller has validated ci_type. + */ +static void client_drop_item(struct config_item *parent_item, + struct config_item *item) +{ + struct config_item_type *type; + + type = parent_item->ci_type; + BUG_ON(!type); + + if (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); +} + + +static int configfs_mkdir(struct inode *dir, struct dentry *dentry, int mode) +{ + int ret; + struct config_group *group; + struct config_item *item; + struct config_item *parent_item; + struct configfs_subsystem *subsys; + struct configfs_dirent *sd; + struct config_item_type *type; + struct module *owner; + char *name; + + if (dentry->d_parent == configfs_sb->s_root) + return -EPERM; + + sd = dentry->d_parent->d_fsdata; + if (!(sd->s_type & CONFIGFS_USET_DIR)) + return -EPERM; + + 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)) { + config_item_put(parent_item); + return -EPERM; /* What lack-of-mkdir returns */ + } + + name = kmalloc(dentry->d_name.len + 1, GFP_KERNEL); + if (!name) { + config_item_put(parent_item); + return -ENOMEM; + } + snprintf(name, dentry->d_name.len + 1, "%s", dentry->d_name.name); + + down(&subsys->su_sem); + group = NULL; + item = NULL; + if (type->ct_group_ops->make_group) { + group = type->ct_group_ops->make_group(to_config_group(parent_item), name); + if (group) { + link_group(to_config_group(parent_item), group); + item = &group->cg_item; + } + } else { + item = type->ct_group_ops->make_item(to_config_group(parent_item), name); + if (item) + link_obj(parent_item, item); + } + up(&subsys->su_sem); + + kfree(name); + if (!item) { + config_item_put(parent_item); + return -ENOMEM; + } + + ret = -EINVAL; + type = item->ci_type; + if (type) { + owner = type->ct_owner; + if (try_module_get(owner)) { + if (group) { + ret = configfs_attach_group(parent_item, + item, + dentry); + } else { + ret = configfs_attach_item(parent_item, + item, + dentry); + } + + if (ret) { + down(&subsys->su_sem); + if (group) + unlink_group(group); + else + unlink_obj(item); + client_drop_item(parent_item, item); + up(&subsys->su_sem); + + config_item_put(parent_item); + module_put(owner); + } + } + } + + return ret; +} + +static int configfs_rmdir(struct inode *dir, struct dentry *dentry) +{ + struct config_item *parent_item; + struct config_item *item; + struct configfs_subsystem *subsys; + struct configfs_dirent *sd; + struct module *owner = NULL; + int ret; + + if (dentry->d_parent == configfs_sb->s_root) + return -EPERM; + + sd = dentry->d_fsdata; + if (sd->s_type & CONFIGFS_USET_DEFAULT) + return -EPERM; + + 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; + } + + ret = configfs_detach_prep(dentry); + if (ret) { + configfs_detach_rollback(dentry); + config_item_put(parent_item); + return ret; + } + + item = configfs_get_config_item(dentry); + + /* Drop reference from above, item already holds one. */ + config_item_put(parent_item); + + if (item->ci_type) + owner = item->ci_type->ct_owner; + + if (sd->s_type & CONFIGFS_USET_DIR) { + configfs_detach_group(item); + + down(&subsys->su_sem); + unlink_group(to_config_group(item)); + } else { + configfs_detach_item(item); + + down(&subsys->su_sem); + unlink_obj(item); + } + + client_drop_item(parent_item, item); + up(&subsys->su_sem); + + /* Drop our reference from above */ + config_item_put(item); + + module_put(owner); + + return 0; +} + +struct inode_operations configfs_dir_inode_operations = { + .mkdir = configfs_mkdir, + .rmdir = configfs_rmdir, + .symlink = configfs_symlink, + .unlink = configfs_unlink, + .lookup = configfs_lookup, +}; + +#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; + + 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 = 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); + } + up(&parent->d_inode->i_sem); + up_write(&configfs_rename_sem); + + return error; +} +#endif + +static int configfs_dir_open(struct inode *inode, struct file *file) +{ + struct dentry * dentry = file->f_dentry; + struct configfs_dirent * parent_sd = dentry->d_fsdata; + + down(&dentry->d_inode->i_sem); + file->private_data = configfs_new_dirent(parent_sd, NULL); + up(&dentry->d_inode->i_sem); + + return file->private_data ? 0 : -ENOMEM; + +} + +static int configfs_dir_close(struct inode *inode, struct file *file) +{ + struct dentry * dentry = file->f_dentry; + struct configfs_dirent * cursor = file->private_data; + + down(&dentry->d_inode->i_sem); + list_del_init(&cursor->s_sibling); + up(&dentry->d_inode->i_sem); + + release_configfs_dirent(cursor); + + return 0; +} + +/* Relationship between s_mode and the DT_xxx types */ +static inline unsigned char dt_type(struct configfs_dirent *sd) +{ + return (sd->s_mode >> 12) & 15; +} + +static int configfs_readdir(struct file * filp, void * dirent, filldir_t filldir) +{ + struct dentry *dentry = filp->f_dentry; + struct configfs_dirent * parent_sd = dentry->d_fsdata; + struct configfs_dirent *cursor = filp->private_data; + struct list_head *p, *q = &cursor->s_sibling; + ino_t ino; + 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 configfs_dirent *next; + const char * name; + int len; + + next = list_entry(p, struct configfs_dirent, + s_sibling); + if (!next->s_element) + continue; + + name = configfs_get_name(next); + len = strlen(name); + if (next->s_dentry) + ino = next->s_dentry->d_inode->i_ino; + else + ino = iunique(configfs_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 configfs_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 configfs_dirent *sd = dentry->d_fsdata; + struct configfs_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 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); + } + } + up(&dentry->d_inode->i_sem); + return offset; +} + +struct file_operations configfs_dir_operations = { + .open = configfs_dir_open, + .release = configfs_dir_close, + .llseek = configfs_dir_lseek, + .read = generic_read_dir, + .readdir = configfs_readdir, +}; + +int configfs_register_subsystem(struct configfs_subsystem *subsys) +{ + int err; + struct config_group *group = &subsys->su_group; + struct qstr name; + struct dentry *dentry; + struct configfs_dirent *sd; + + err = configfs_pin_fs(); + if (err) + return err; + + if (!group->cg_item.ci_name) + group->cg_item.ci_name = group->cg_item.ci_namebuf; + + sd = configfs_sb->s_root->d_fsdata; + link_group(to_config_group(sd->s_element), group); + + down(&configfs_sb->s_root->d_inode->i_sem); + + name.name = group->cg_item.ci_name; + name.len = strlen(name.name); + name.hash = full_name_hash(name.name, name.len); + + err = -ENOMEM; + dentry = d_alloc(configfs_sb->s_root, &name); + if (!dentry) + goto out_release; + + d_add(dentry, NULL); + + err = configfs_attach_group(sd->s_element, &group->cg_item, + dentry); + if (!err) + dentry = NULL; + else + d_delete(dentry); + + up(&configfs_sb->s_root->d_inode->i_sem); + + if (dentry) { + dput(dentry); +out_release: + unlink_group(group); + configfs_release_fs(); + } + + return err; +} + +void configfs_unregister_subsystem(struct configfs_subsystem *subsys) +{ + struct config_group *group = &subsys->su_group; + struct dentry *dentry = group->cg_item.ci_dentry; + + if (dentry->d_parent != configfs_sb->s_root) { + printk(KERN_ERR "configfs: Tried to unregister non-subsystem!\n"); + return; + } + + down(&configfs_sb->s_root->d_inode->i_sem); + down(&dentry->d_inode->i_sem); + if (configfs_detach_prep(dentry)) { + printk(KERN_ERR "configfs: Tried to unregister non-empty subsystem!\n"); + } + configfs_detach_group(&group->cg_item); + dentry->d_inode->i_flags |= S_DEAD; + up(&dentry->d_inode->i_sem); + + d_delete(dentry); + + up(&configfs_sb->s_root->d_inode->i_sem); + + dput(dentry); + + unlink_group(group); + configfs_release_fs(); +} + +EXPORT_SYMBOL(configfs_register_subsystem); +EXPORT_SYMBOL(configfs_unregister_subsystem); |