dir.c 27.2 KB
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/* -*- 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;

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	sd = kmem_cache_alloc(configfs_dir_cachep, GFP_KERNEL);
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	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;
}

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/*
 *
 * 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
 */
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;
}


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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;

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	error = configfs_dirent_exists(p->d_fsdata, d->d_name.name);
	if (!error)
		error = configfs_make_dirent(p->d_fsdata, d, k, mode,
					     CONFIGFS_DIR);
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	if (!error) {
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		error = configfs_create(d, mode, init_dir);
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		if (!error) {
			p->d_inode->i_nlink++;
			(d)->d_op = &configfs_dentry_ops;
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		} else {
			struct configfs_dirent *sd = d->d_fsdata;
			if (sd) {
				list_del_init(&sd->s_sibling);
				configfs_put(sd);
			}
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		}
	}
	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;

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	err = configfs_make_dirent(parent->d_fsdata, dentry, sl, mode,
				   CONFIGFS_ITEM_LINK);
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	if (!err) {
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		err = configfs_create(dentry, mode, init_symlink);
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		if (!err)
			dentry->d_op = &configfs_dentry_ops;
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		else {
			struct configfs_dirent *sd = dentry->d_fsdata;
			if (sd) {
				list_del_init(&sd->s_sibling);
				configfs_put(sd);
			}
		}
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	}
	return err;
}

static void remove_dir(struct dentry * d)
{
	struct dentry * parent = dget(d->d_parent);
	struct configfs_dirent * sd;

	sd = d->d_fsdata;
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	list_del_init(&sd->s_sibling);
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	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;

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	dentry->d_fsdata = configfs_get(sd);
	sd->s_dentry = dentry;
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	error = configfs_create(dentry, (attr->ca_mode & S_IALLUGO) | S_IFREG, init_file);
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	if (error) {
		configfs_put(sd);
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		return error;
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	}
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	dentry->d_op = &configfs_dentry_ops;
	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
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 * attributes and are removed by rmdir().  We recurse, taking i_mutex
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 * on all children that are candidates for default detach.  If the
 * result is clean, then configfs_detach_group() will handle dropping
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 * i_mutex.  If there is an error, the caller will clean up the i_mutex
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 * 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) {
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			mutex_lock(&sd->s_dentry->d_inode->i_mutex);
			/* Mark that we've taken i_mutex */
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			sd->s_type |= CONFIGFS_USET_DROPPING;

			ret = configfs_detach_prep(sd->s_dentry);
			if (!ret)
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				continue;
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		} else
			ret = -ENOTEMPTY;

		break;
	}

out:
	return ret;
}

/*
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 * Walk the tree, dropping i_mutex wherever CONFIGFS_USET_DROPPING is
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 * 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;
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				mutex_unlock(&sd->s_dentry->d_inode->i_mutex);
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			}
		}
	}
}

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
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		 * has taken our i_mutex for us.  Drop it.
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		 * From mkdir/register cleanup, there is no sem held.
		 */
		if (sd->s_type & CONFIGFS_USET_DROPPING)
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			mutex_unlock(&child->d_inode->i_mutex);
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		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;

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	if (group->default_groups) {
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		/*
		 * FYI, we're faking mkdir here
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		 * I'm not sure we need this semaphore, as we're called
		 * from our parent's mkdir.  That holds our parent's
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		 * i_mutex, so afaik lookup cannot continue through our
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		 * parent to find us, let alone mess with our tree.
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		 * That said, taking our i_mutex is closer to mkdir
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		 * emulation, and shouldn't hurt.
		 */
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		mutex_lock(&dentry->d_inode->i_mutex);
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		for (i = 0; group->default_groups[i]; i++) {
			new_group = group->default_groups[i];

			ret = create_default_group(group, new_group);
			if (ret)
				break;
		}

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		mutex_unlock(&dentry->d_inode->i_mutex);
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	}

	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;
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		/* Drop the reference for ci_entry */
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		config_item_put(item);

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		/* Drop the reference for ci_parent */
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		config_group_put(group);
	}
}

static void link_obj(struct config_item *parent_item, struct config_item *item)
{
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	/*
	 * Parent seems redundant with group, but it makes certain
	 * traversals much nicer.
	 */
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	item->ci_parent = parent_item;
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	/*
	 * We hold a reference on the parent for the child's ci_parent
	 * link.
	 */
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	item->ci_group = config_group_get(to_config_group(parent_item));
	list_add_tail(&item->ci_entry, &item->ci_group->cg_children);

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	/*
	 * We hold a reference on the child for ci_entry on the parent's
	 * cg_children
	 */
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	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);

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	/*
	 * If ->drop_item() exists, it is responsible for the
	 * config_item_put().
	 */
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	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)
{
745
	int ret, module_got = 0;
746 747 748 749 750 751
	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;
752
	struct module *owner = NULL;
753 754
	char *name;

755 756 757 758
	if (dentry->d_parent == configfs_sb->s_root) {
		ret = -EPERM;
		goto out;
	}
759 760

	sd = dentry->d_parent->d_fsdata;
761 762 763 764
	if (!(sd->s_type & CONFIGFS_USET_DIR)) {
		ret = -EPERM;
		goto out;
	}
765

766
	/* Get a working ref for the duration of this function */
767 768 769 770 771 772 773 774
	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)) {
775 776
		ret = -EPERM;  /* Lack-of-mkdir returns -EPERM */
		goto out_put;
777 778 779 780
	}

	name = kmalloc(dentry->d_name.len + 1, GFP_KERNEL);
	if (!name) {
781 782
		ret = -ENOMEM;
		goto out_put;
783
	}
784

785 786 787 788 789 790 791 792 793 794 795 796 797 798 799 800 801 802 803 804
	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) {
805 806 807 808
		/*
		 * If item == NULL, then link_obj() was never called.
		 * There are no extra references to clean up.
		 */
809 810
		ret = -ENOMEM;
		goto out_put;
811 812
	}

813 814 815 816 817
	/*
	 * link_obj() has been called (via link_group() for groups).
	 * From here on out, errors must clean that up.
	 */

818
	type = item->ci_type;
819 820 821 822
	if (!type) {
		ret = -EINVAL;
		goto out_unlink;
	}
823

824 825 826 827 828
	owner = type->ct_owner;
	if (!try_module_get(owner)) {
		ret = -EINVAL;
		goto out_unlink;
	}
829

830 831 832 833 834 835 836 837 838 839 840 841 842 843 844 845 846 847 848 849 850 851 852 853 854
	/*
	 * I hate doing it this way, but if there is
	 * an error,  module_put() probably should
	 * happen after any cleanup.
	 */
	module_got = 1;

	if (group)
		ret = configfs_attach_group(parent_item, item, dentry);
	else
		ret = configfs_attach_item(parent_item, item, dentry);

out_unlink:
	if (ret) {
		/* Tear down everything we built up */
		down(&subsys->su_sem);
		if (group)
			unlink_group(group);
		else
			unlink_obj(item);
		client_drop_item(parent_item, item);
		up(&subsys->su_sem);

		if (module_got)
			module_put(owner);
855 856
	}

857 858
out_put:
	/*
859 860 861
	 * link_obj()/link_group() took a reference from child->parent,
	 * so the parent is safely pinned.  We can drop our working
	 * reference.
862 863 864 865
	 */
	config_item_put(parent_item);

out:
866 867 868 869 870 871 872 873 874 875 876 877 878 879 880 881 882 883 884
	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;

885
	/* Get a working ref until we have the child */
886 887 888 889 890 891 892 893 894 895 896 897 898 899 900 901
	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;
	}

902
	/* Get a working ref for the duration of this function */
903 904 905 906 907 908 909 910 911 912 913 914 915 916 917 918 919 920 921 922 923 924 925 926 927 928 929 930 931 932 933 934 935 936 937 938 939
	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,
940
	.setattr	= configfs_setattr,
941 942 943 944 945 946 947 948 949 950 951 952 953 954 955 956 957
};

#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;

958
	mutex_lock(&parent->d_inode->i_mutex);
959 960 961

	new_dentry = lookup_one_len(new_name, parent, strlen(new_name));
	if (!IS_ERR(new_dentry)) {
962
		if (!new_dentry->d_inode) {
963 964 965 966 967 968 969 970 971 972 973
			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);
	}
974
	mutex_unlock(&parent->d_inode->i_mutex);
975 976 977 978 979 980 981 982 983 984 985
	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;

986
	mutex_lock(&dentry->d_inode->i_mutex);
987
	file->private_data = configfs_new_dirent(parent_sd, NULL);
988
	mutex_unlock(&dentry->d_inode->i_mutex);
989 990 991 992 993 994 995 996 997 998

	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;

999
	mutex_lock(&dentry->d_inode->i_mutex);
1000
	list_del_init(&cursor->s_sibling);
1001
	mutex_unlock(&dentry->d_inode->i_mutex);
1002 1003 1004 1005 1006 1007 1008 1009 1010 1011 1012 1013 1014 1015 1016 1017 1018 1019 1020 1021 1022 1023 1024 1025 1026 1027 1028 1029 1030 1031 1032 1033 1034 1035 1036 1037 1038 1039

	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) {
A
Akinobu Mita 已提交
1040
				list_move(q, &parent_sd->s_children);
1041 1042 1043 1044 1045 1046 1047 1048 1049 1050 1051 1052 1053 1054 1055 1056 1057 1058 1059 1060 1061 1062
			}
			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;

A
Akinobu Mita 已提交
1063
				list_move(q, p);
1064 1065 1066 1067 1068 1069 1070 1071 1072 1073 1074
				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;

1075
	mutex_lock(&dentry->d_inode->i_mutex);
1076 1077 1078 1079 1080 1081 1082
	switch (origin) {
		case 1:
			offset += file->f_pos;
		case 0:
			if (offset >= 0)
				break;
		default:
1083
			mutex_unlock(&file->f_dentry->d_inode->i_mutex);
1084 1085 1086 1087 1088 1089 1090 1091 1092 1093 1094 1095 1096 1097 1098 1099 1100 1101 1102 1103 1104 1105 1106
			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);
		}
	}
1107
	mutex_unlock(&dentry->d_inode->i_mutex);
1108 1109 1110
	return offset;
}

1111
const struct file_operations configfs_dir_operations = {
1112 1113 1114 1115 1116 1117 1118 1119 1120 1121 1122 1123 1124 1125 1126 1127 1128 1129 1130 1131 1132 1133 1134 1135 1136
	.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);

1137
	mutex_lock(&configfs_sb->s_root->d_inode->i_mutex);
1138 1139 1140 1141 1142 1143 1144 1145 1146 1147 1148 1149 1150 1151 1152 1153 1154 1155 1156

	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);

1157
	mutex_unlock(&configfs_sb->s_root->d_inode->i_mutex);
1158 1159 1160 1161 1162 1163 1164 1165 1166 1167 1168 1169 1170 1171 1172 1173 1174 1175 1176 1177 1178

	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;
	}

1179 1180
	mutex_lock(&configfs_sb->s_root->d_inode->i_mutex);
	mutex_lock(&dentry->d_inode->i_mutex);
1181 1182 1183 1184 1185
	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;
1186
	mutex_unlock(&dentry->d_inode->i_mutex);
1187 1188 1189

	d_delete(dentry);

1190
	mutex_unlock(&configfs_sb->s_root->d_inode->i_mutex);
1191 1192 1193 1194 1195 1196 1197 1198 1199

	dput(dentry);

	unlink_group(group);
	configfs_release_fs();
}

EXPORT_SYMBOL(configfs_register_subsystem);
EXPORT_SYMBOL(configfs_unregister_subsystem);