Release 4.10 fs/configfs/dir.c

/* -*- mode: c; c-basic-offset: 8; -*-
 * vim: noexpandtab sw=8 ts=8 sts=0:
 *
 * dir.c - Operations for configfs directories.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public
 * License along with this program; if not, write to the
 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
 * Boston, MA 021110-1307, USA.
 *
 * Based on sysfs:
 *      sysfs is Copyright (C) 2001, 2002, 2003 Patrick Mochel
 *
 * configfs Copyright (C) 2005 Oracle.  All rights reserved.
 */


#undef DEBUG

#include <linux/fs.h>
#include <linux/mount.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/err.h>

#include <linux/configfs.h>
#include "configfs_internal.h"


DECLARE_RWSEM(configfs_rename_sem);
/*
 * Protects mutations of configfs_dirent linkage together with proper i_mutex
 * Also protects mutations of symlinks linkage to target configfs_dirent
 * Mutators of configfs_dirent linkage must *both* have the proper inode locked
 * and configfs_dirent_lock locked, in that order.
 * This allows one to safely traverse configfs_dirent trees and symlinks without
 * having to lock inodes.
 *
 * Protects setting of CONFIGFS_USET_DROPPING: checking the flag
 * unlocked is not reliable unless in detach_groups() called from
 * rmdir()/unregister() and from configfs_attach_group()
 */

DEFINE_SPINLOCK(configfs_dirent_lock);



static void configfs_d_iput(struct dentry * dentry,
			    struct inode * inode)
{
	struct configfs_dirent *sd = dentry->d_fsdata;

	if (sd) {
		/* Coordinate with configfs_readdir */
		spin_lock(&configfs_dirent_lock);
		/* Coordinate with configfs_attach_attr where will increase
                 * sd->s_count and update sd->s_dentry to new allocated one.
                 * Only set sd->dentry to null when this dentry is the only
                 * sd owner.
                 * If not do so, configfs_d_iput may run just after
                 * configfs_attach_attr and set sd->s_dentry to null
                 * even it's still in use.
                 */
		if (atomic_read(&sd->s_count) <= 2)
			sd->s_dentry = NULL;

		spin_unlock(&configfs_dirent_lock);
		configfs_put(sd);
	}
	iput(inode);
}

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const struct dentry_operations configfs_dentry_ops = {
	.d_iput		= configfs_d_iput,
	.d_delete	= always_delete_dentry,
};

#ifdef CONFIG_LOCKDEP

/*
 * Helpers to make lockdep happy with our recursive locking of default groups'
 * inodes (see configfs_attach_group() and configfs_detach_group()).
 * We put default groups i_mutexes in separate classes according to their depth
 * from the youngest non-default group ancestor.
 *
 * For a non-default group A having default groups A/B, A/C, and A/C/D, default
 * groups A/B and A/C will have their inode's mutex in class
 * default_group_class[0], and default group A/C/D will be in
 * default_group_class[1].
 *
 * The lock classes are declared and assigned in inode.c, according to the
 * s_depth value.
 * The s_depth value is initialized to -1, adjusted to >= 0 when attaching
 * default groups, and reset to -1 when all default groups are attached. During
 * attachment, if configfs_create() sees s_depth > 0, the lock class of the new
 * inode's mutex is set to default_group_class[s_depth - 1].
 */



static void configfs_init_dirent_depth(struct configfs_dirent *sd)
{
	sd->s_depth = -1;
}

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static void configfs_set_dir_dirent_depth(struct configfs_dirent *parent_sd,
					  struct configfs_dirent *sd)
{
	int parent_depth = parent_sd->s_depth;

	if (parent_depth >= 0)
		sd->s_depth = parent_depth + 1;
}

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static void

configfs_adjust_dir_dirent_depth_before_populate(struct configfs_dirent *sd)
{
	/*
         * item's i_mutex class is already setup, so s_depth is now only
         * used to set new sub-directories s_depth, which is always done
         * with item's i_mutex locked.
         */
	/*
         *  sd->s_depth == -1 iff we are a non default group.
         *  else (we are a default group) sd->s_depth > 0 (see
         *  create_dir()).
         */
	if (sd->s_depth == -1)
		/*
                 * We are a non default group and we are going to create
                 * default groups.
                 */
		sd->s_depth = 0;
}

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static void

configfs_adjust_dir_dirent_depth_after_populate(struct configfs_dirent *sd)
{
	/* We will not create default groups anymore. */
	sd->s_depth = -1;
}

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#else /* CONFIG_LOCKDEP */



static void configfs_init_dirent_depth(struct configfs_dirent *sd)
{
}

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static void configfs_set_dir_dirent_depth(struct configfs_dirent *parent_sd,
					  struct configfs_dirent *sd)
{
}

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static void

configfs_adjust_dir_dirent_depth_before_populate(struct configfs_dirent *sd)
{
}

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static void

configfs_adjust_dir_dirent_depth_after_populate(struct configfs_dirent *sd)
{
}

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#endif /* CONFIG_LOCKDEP */

/*
 * Allocates a new configfs_dirent and links it to the parent configfs_dirent
 */


static struct configfs_dirent *configfs_new_dirent(struct configfs_dirent *parent_sd,
						   void *element, int type)
{
	struct configfs_dirent * sd;

	sd = kmem_cache_zalloc(configfs_dir_cachep, GFP_KERNEL);
	if (!sd)
		return ERR_PTR(-ENOMEM);

	atomic_set(&sd->s_count, 1);
	INIT_LIST_HEAD(&sd->s_links);
	INIT_LIST_HEAD(&sd->s_children);
	sd->s_element = element;
	sd->s_type = type;
	configfs_init_dirent_depth(sd);
	spin_lock(&configfs_dirent_lock);
	if (parent_sd->s_type & CONFIGFS_USET_DROPPING) {
		spin_unlock(&configfs_dirent_lock);
		kmem_cache_free(configfs_dir_cachep, sd);
		return ERR_PTR(-ENOENT);
	}
	list_add(&sd->s_sibling, &parent_sd->s_children);
	spin_unlock(&configfs_dirent_lock);

	return sd;
}

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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
 */


static int configfs_dirent_exists(struct configfs_dirent *parent_sd,
				  const unsigned char *new)
{
	struct configfs_dirent * sd;

	list_for_each_entry(sd, &parent_sd->s_children, s_sibling) {
		if (sd->s_element) {
			const unsigned char *existing = configfs_get_name(sd);
			if (strcmp(existing, new))
				continue;
			else
				return -EEXIST;
		}
	}

	return 0;
}


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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, type);
	if (IS_ERR(sd))
		return PTR_ERR(sd);

	sd->s_mode = mode;
	sd->s_dentry = dentry;
	if (dentry)
		dentry->d_fsdata = configfs_get(sd);

	return 0;
}

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static void init_dir(struct inode * inode)
{
	inode->i_op = &configfs_dir_inode_operations;
	inode->i_fop = &configfs_dir_operations;

	/* directory inodes start off with i_nlink == 2 (for "." entry) */
	inc_nlink(inode);
}

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static void configfs_init_file(struct inode * inode)
{
	inode->i_size = PAGE_SIZE;
	inode->i_fop = &configfs_file_operations;
}

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static void configfs_init_bin_file(struct inode *inode)
{
	inode->i_size = 0;
	inode->i_fop = &configfs_bin_file_operations;
}

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static void init_symlink(struct inode * inode)
{
	inode->i_op = &configfs_symlink_inode_operations;
}

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/**
 *      configfs_create_dir - create a directory for an config_item.
 *      @item:          config_itemwe're creating directory for.
 *      @dentry:        config_item's dentry.
 *
 *      Note: user-created entries won't be allowed under this new directory
 *      until it is validated by configfs_dir_set_ready()
 */



static int configfs_create_dir(struct config_item *item, struct dentry *dentry)
{
	int error;
	umode_t mode = S_IFDIR| S_IRWXU | S_IRUGO | S_IXUGO;
	struct dentry *p = dentry->d_parent;

	BUG_ON(!item);

	error = configfs_dirent_exists(p->d_fsdata, dentry->d_name.name);
	if (unlikely(error))
		return error;

	error = configfs_make_dirent(p->d_fsdata, dentry, item, mode,
				     CONFIGFS_DIR | CONFIGFS_USET_CREATING);
	if (unlikely(error))
		return error;

	configfs_set_dir_dirent_depth(p->d_fsdata, dentry->d_fsdata);
	error = configfs_create(dentry, mode, init_dir);
	if (!error) {
		inc_nlink(d_inode(p));
		item->ci_dentry = dentry;
	} else {
		struct configfs_dirent *sd = dentry->d_fsdata;
		if (sd) {
			spin_lock(&configfs_dirent_lock);
			list_del_init(&sd->s_sibling);
			spin_unlock(&configfs_dirent_lock);
			configfs_put(sd);
		}
	}
	return error;
}

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/*
 * Allow userspace to create new entries under a new directory created with
 * configfs_create_dir(), and under all of its chidlren directories recursively.
 * @sd          configfs_dirent of the new directory to validate
 *
 * Caller must hold configfs_dirent_lock.
 */


static void configfs_dir_set_ready(struct configfs_dirent *sd)
{
	struct configfs_dirent *child_sd;

	sd->s_type &= ~CONFIGFS_USET_CREATING;
	list_for_each_entry(child_sd, &sd->s_children, s_sibling)
		if (child_sd->s_type & CONFIGFS_USET_CREATING)
			configfs_dir_set_ready(child_sd);
}

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/*
 * Check that a directory does not belong to a directory hierarchy being
 * attached and not validated yet.
 * @sd          configfs_dirent of the directory to check
 *
 * @return      non-zero iff the directory was validated
 *
 * Note: takes configfs_dirent_lock, so the result may change from false to true
 * in two consecutive calls, but never from true to false.
 */


int configfs_dirent_is_ready(struct configfs_dirent *sd)
{
	int ret;

	spin_lock(&configfs_dirent_lock);
	ret = !(sd->s_type & CONFIGFS_USET_CREATING);
	spin_unlock(&configfs_dirent_lock);

	return ret;
}

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int configfs_create_link(struct configfs_symlink *sl,
			 struct dentry *parent,
			 struct dentry *dentry)
{
	int err = 0;
	umode_t mode = S_IFLNK | S_IRWXUGO;

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

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

	sd = d->d_fsdata;
	spin_lock(&configfs_dirent_lock);
	list_del_init(&sd->s_sibling);
	spin_unlock(&configfs_dirent_lock);
	configfs_put(sd);
	if (d_really_is_positive(d))
		simple_rmdir(d_inode(parent),d);

	pr_debug(" o %pd removing done (%d)\n", d, d_count(d));

	dput(parent);
}

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/**
 * configfs_remove_dir - remove an config_item's directory.
 * @item:       config_item we're removing.
 *
 * The only thing special about this is that we remove any files in
 * the directory before we remove the directory, and we've inlined
 * what used to be configfs_rmdir() below, instead of calling separately.
 *
 * Caller holds the mutex of the item's inode
 */



static void configfs_remove_dir(struct config_item * item)
{
	struct dentry * dentry = dget(item->ci_dentry);

	if (!dentry)
		return;

	remove_dir(dentry);
	/**
         * Drop reference from dget() on entrance.
         */
	dput(dentry);
}


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/* attaches attribute's configfs_dirent to the dentry corresponding to the
 * attribute file
 */


static int configfs_attach_attr(struct configfs_dirent * sd, struct dentry * dentry)
{
	struct configfs_attribute * attr = sd->s_element;
	int error;

	spin_lock(&configfs_dirent_lock);
	dentry->d_fsdata = configfs_get(sd);
	sd->s_dentry = dentry;
	spin_unlock(&configfs_dirent_lock);

	error = configfs_create(dentry, (attr->ca_mode & S_IALLUGO) | S_IFREG,
				(sd->s_type & CONFIGFS_ITEM_BIN_ATTR) ?
					configfs_init_bin_file :
					configfs_init_file);
	if (error)
		configfs_put(sd);
	return error;
}

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static struct dentry * configfs_lookup(struct inode *dir,
				       struct dentry *dentry,
				       unsigned int flags)
{
	struct configfs_dirent * parent_sd = dentry->d_parent->d_fsdata;
	struct configfs_dirent * sd;
	int found = 0;
	int err;

	/*
         * Fake invisibility if dir belongs to a group/default groups hierarchy
         * being attached
         *
         * This forbids userspace to read/write attributes of items which may
         * not complete their initialization, since the dentries of the
         * attributes won't be instantiated.
         */
	err = -ENOENT;
	if (!configfs_dirent_is_ready(parent_sd))
		goto out;

	list_for_each_entry(sd, &parent_sd->s_children, s_sibling) {
		if (sd->s_type & CONFIGFS_NOT_PINNED) {
			const unsigned char * name = configfs_get_name(sd);

			if (strcmp(name, dentry->d_name.name))
				continue;

			found = 1;
			err = configfs_attach_attr(sd, dentry);
			break;
		}
	}

	if (!found) {
		/*
                 * If it doesn't exist and it isn't a NOT_PINNED item,
                 * it must be negative.
                 */
		if (dentry->d_name.len > NAME_MAX)
			return ERR_PTR(-ENAMETOOLONG);
		d_add(dentry, NULL);
		return NULL;
	}

out:
	return ERR_PTR(err);
}

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/*
 * Only subdirectories count here.  Files (CONFIGFS_NOT_PINNED) are
 * attributes and are removed by rmdir().  We recurse, setting
 * CONFIGFS_USET_DROPPING on all children that are candidates for
 * default detach.
 * If there is an error, the caller will reset the flags via
 * configfs_detach_rollback().
 */


static int configfs_detach_prep(struct dentry *dentry, struct dentry **wait)
{
	struct configfs_dirent *parent_sd = dentry->d_fsdata;
	struct configfs_dirent *sd;
	int ret;

	/* Mark that we're trying to drop the group */
	parent_sd->s_type |= CONFIGFS_USET_DROPPING;

	ret = -EBUSY;
	if (!list_empty(&parent_sd->s_links))
		goto out;

	ret = 0;
	list_for_each_entry(sd, &parent_sd->s_children, s_sibling) {
		if (!sd->s_element ||
		    (sd->s_type & CONFIGFS_NOT_PINNED))
			continue;
		if (sd->s_type & CONFIGFS_USET_DEFAULT) {
			/* Abort if racing with mkdir() */
			if (sd->s_type & CONFIGFS_USET_IN_MKDIR) {
				if (wait)
					*wait= dget(sd->s_dentry);
				return -EAGAIN;
			}

			/*
                         * Yup, recursive.  If there's a problem, blame
                         * deep nesting of default_groups
                         */
			ret = configfs_detach_prep(sd->s_dentry, wait);
			if (!ret)
				continue;
		} else
			ret = -ENOTEMPTY;

		break;
	}

out:
	return ret;
}

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louis rilling
43
27.04%
3
42.86%
al viro
al viro
6
3.77%
1
14.29%
david howells
david howells
2
1.26%
1
14.29%
Total
159
100.00%
7
100.00%

/*
 * Walk the tree, resetting CONFIGFS_USET_DROPPING wherever it was
 * set.
 */


static void configfs_detach_rollback(struct dentry *dentry)
{
	struct configfs_dirent *parent_sd = dentry->d_fsdata;
	struct configfs_dirent *sd;

	parent_sd->s_type &= ~CONFIGFS_USET_DROPPING;

	list_for_each_entry(sd, &parent_sd->s_children, s_sibling)
		if (sd->s_type & CONFIGFS_USET_DEFAULT)
			configfs_detach_rollback(sd->s_dentry);
}

Contributors
Person
Tokens
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Commits
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joel becker
joel becker
48
87.27%
1
50.00%
louis rilling
louis rilling
7
12.73%
1
50.00%
Total
55
100.00%
2
100.00%



static void detach_attrs(struct config_item * item)
{
	struct dentry * dentry = dget(item->ci_dentry);
	struct configfs_dirent * parent_sd;
	struct configfs_dirent * sd, * tmp;

	if (!dentry)
		return;

	pr_debug("configfs %s: dropping attrs for  dir\n",
		 dentry->d_name.name);

	parent_sd = dentry->d_fsdata;
	list_for_each_entry_safe(sd, tmp, &parent_sd->s_children, s_sibling) {
		if (!sd->s_element || !(sd->s_type & CONFIGFS_NOT_PINNED))
			continue;
		spin_lock(&configfs_dirent_lock);
		list_del_init(&sd->s_sibling);
		spin_unlock(&configfs_dirent_lock);
		configfs_drop_dentry(sd, dentry);
		configfs_put(sd);
	}

	/**
         * Drop reference from dget() on entrance.
         */
	dput(dentry);
}

Contributors
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joel becker
joel becker
114
90.48%
1
50.00%
louis rilling
louis rilling
12
9.52%
1
50.00%
Total
126
100.00%
2
100.00%



static int populate_attrs(struct config_item *item)
{
	struct config_item_type *t = item->ci_type;
	struct configfs_attribute *attr;
	struct configfs_bin_attribute *bin_attr;
	int error = 0;
	int i;

	if (!t)
		return -EINVAL;
	if (t->ct_attrs) {
		for (i = 0; (attr = t->ct_attrs[i]) != NULL; i++) {
			if ((error = configfs_create_file(item, attr)))
				break;
		}
	}
	if (t->ct_bin_attrs) {
		for (i = 0; (bin_attr = t->ct_bin_attrs[i]) != NULL; i++) {
			error = configfs_create_bin_file(item, bin_attr);
			if (error)
				break;
		}
	}

	if (error)
		detach_attrs(item);

	return error;
}

Contributors
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Tokens
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Commits
CommitProp
joel becker
joel becker
100
66.23%
1
50.00%
pantelis antoniou
pantelis antoniou
51
33.77%
1
50.00%
Total
151
100.00%
2
100.00%

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;

		inode_lock(d_inode(child));

		configfs_detach_group(sd->s_element);
		d_inode(child)->i_flags |= S_DEAD;
		dont_mount(child);

		inode_unlock(d_inode(child));

		d_delete(child);
		dput(child);
	}

	/**
         * Drop reference from dget() on entrance.
         */
	dput(dentry);
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
joel becker
joel becker
123
86.01%
1
20.00%
david howells
david howells
9
6.29%
1
20.00%
al viro
al viro
7
4.90%
2
40.00%
louis rilling
louis rilling
4
2.80%
1
20.00%
Total
143
100.00%
5
100.00%

/*
 * 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 configfs_dirent *sd;
	/* We trust the caller holds a reference to parent */
	struct dentry *child, *parent = parent_group->cg_item.ci_dentry;

	if (!group->cg_item.ci_name)
		group->cg_item.ci_name = group->cg_item.ci_namebuf;

	ret = -ENOMEM;
	child = d_alloc_name(parent, group->cg_item.ci_name);
	if (child) {
		d_add(child, NULL);

		ret = configfs_attach_group(&parent_group->cg_item,
					    &group->cg_item, child);
		if (!ret) {
			sd = child->d_fsdata;
			sd->s_type |= CONFIGFS_USET_DEFAULT;
		} else {
			BUG_ON(d_inode(child));
			d_drop(child);
			dput(child);
		}
	}

	return ret;
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
joel becker
joel becker
142
94.04%
2
50.00%
al viro
al viro
6
3.97%
1
25.00%
david howells
david howells
3
1.99%
1
25.00%
Total
151
100.00%
4
100.00%



static int populate_groups(struct config_group *group)
{
	struct config_group *new_group;
	int ret = 0;

	list_for_each_entry(new_group, &group->default_groups, group_entry) {
		ret = create_default_group(group, new_group);
		if (ret) {
			detach_groups(group);
			break;
		}
	}

	return ret;
}

Contributors
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Commits
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joel becker
joel becker
43
78.18%
1
33.33%
christoph hellwig
christoph hellwig
8
14.55%
1
33.33%
louis rilling
louis rilling
4
7.27%
1
33.33%
Total
55
100.00%
3
100.00%



void configfs_remove_default_groups(struct config_group *group)
{
	struct config_group *g, *n;

	list_for_each_entry_safe(g, n, &group->default_groups, group_entry) {
		list_del(&g->group_entry);
		config_item_put(&g->cg_item);
	}
}
Contributors
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christoph hellwig
christoph hellwig
46
100.00%
1
100.00%
Total
46
100.00%
1
100.00%


EXPORT_SYMBOL(configfs_remove_default_groups);

/*
 * All of link_obj/unlink_obj/link_group/unlink_group require that
 * subsys->su_mutex is held.
 */



static void unlink_obj(struct config_item *item)
{
	struct config_group *group;

	group = item->ci_group;
	if (group) {
		list_del_init(&item->ci_entry);

		item->ci_group = NULL;
		item->ci_parent = NULL;

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

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

Contributors
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joel becker
joel becker
60
100.00%
2
100.00%
Total
60
100.00%
2
100.00%



static void link_obj(struct config_item *parent_item, struct config_item *item)
{
	/*
         * Parent seems redundant with group, but it makes certain
         * traversals much nicer.
         */
	item->ci_parent = parent_item;

	/*
         * We hold a reference on the parent for the child's ci_parent
         * link.
         */
	item->ci_group = config_group_get(to_config_group(parent_item));
	list_add_tail(&item->ci_entry, &item->ci_group->cg_children);

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

Contributors
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joel becker
joel becker
57
100.00%
2
100.00%
Total
57
100.00%
2
100.00%



static void unlink_group(struct config_group *group)
{
	struct config_group *new_group;

	list_for_each_entry(new_group, &group->default_groups, group_entry)
		unlink_group(new_group);

	group->cg_subsys = NULL;
	unlink_obj(&group->cg_item);
}

Contributors
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joel becker
joel becker
35
81.40%
1
50.00%
christoph hellwig
christoph hellwig
8
18.60%
1
50.00%
Total
43
100.00%
2
100.00%



static void link_group(struct config_group *parent_group, struct config_group *group)
{
	struct config_group *new_group;
	struct configfs_subsystem *subsys = NULL; /* gcc is a turd */

	link_obj(&parent_group->cg_item, &group->cg_item);

	if (parent_group->cg_subsys)
		subsys = parent_group->cg_subsys;
	else if (configfs_is_root(&parent_group->cg_item))
		subsys = to_configfs_subsystem(group);
	else
		BUG();
	group->cg_subsys = subsys;

	list_for_each_entry(new_group, &group->default_groups, group_entry)
		link_group(group, new_group);
}

Contributors
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joel becker
joel becker
89
91.75%
1
50.00%
christoph hellwig
christoph hellwig
8
8.25%
1
50.00%
Total
97
100.00%
2
100.00%

/*
 * The goal is that configfs_attach_item() (and
 * configfs_attach_group()) can be called from either the VFS or this
 * module.  That is, they assume that the items have been created,
 * the dentry allocated, and the dcache is all ready to go.
 *
 * If they fail, they must clean up after themselves as if they
 * had never been called.  The caller (VFS or local function) will
 * handle cleaning up the dcache bits.
 *
 * configfs_detach_group() and configfs_detach_item() behave similarly on
 * the way out.  They assume that the proper semaphores are held, they
 * clean up the configfs items, and they expect their callers will
 * handle the dcache bits.
 */


static int configfs_attach_item(struct config_item *parent_item,
				struct config_item *item,
				struct dentry *dentry)
{
	int ret;

	ret = configfs_create_dir(item, dentry);
	if (!ret) {
		ret = populate_attrs(item);
		if (ret) {
			/*
                         * We are going to remove an inode and its dentry but
                         * the VFS may already have hit and used them. Thus,
                         * we must lock them as rmdir() would.
                         */
			inode_lock(d_inode(dentry));
			configfs_remove_dir(item);
			d_inode(dentry)->i_flags |= S_DEAD;
			dont_mount(dentry);
			inode_unlock(d_inode(dentry));
			d_delete(dentry);
		}
	}

	return ret;
}

Contributors
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CommitProp
joel becker
joel becker
66
68.04%
1
16.67%
louis rilling
louis rilling
14
14.43%
1
16.67%
david howells
david howells
9
9.28%
1
16.67%
al viro
al viro
7
7.22%
2
33.33%
mark fasheh
mark fasheh
1
1.03%
1
16.67%
Total
97
100.00%
6
100.00%

/* Caller holds the mutex of the item's inode */


static void configfs_detach_item(struct config_item *item)
{
	detach_attrs(item);
	configfs_remove_dir(item);
}

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joel becker
joel becker
21
100.00%
1
100.00%
Total
21
100.00%
1
100.00%



static int configfs_attach_group(struct config_item *parent_item,
				 struct config_item *item,
				 struct dentry *dentry)
{
	int ret;
	struct