1 files changed, 167 insertions, 139 deletions

diff --git a/fs/configfs/dir.c b/fs/configfs/dir.c
index 92112915de8e..cf7b7e1d5bd7 100644
--- a/fs/configfs/dir.c
+++ b/fs/configfs/dir.c
@@ -22,7 +22,6 @@
 #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
@@ -151,11 +150,38 @@ configfs_adjust_dir_dirent_depth_after_populate(struct configfs_dirent *sd)
 
 #endif /* CONFIG_LOCKDEP */
 
+static struct configfs_fragment *new_fragment(void)
+{
+	struct configfs_fragment *p;
+
+	p = kmalloc(sizeof(struct configfs_fragment), GFP_KERNEL);
+	if (p) {
+		atomic_set(&p->frag_count, 1);
+		init_rwsem(&p->frag_sem);
+		p->frag_dead = false;
+	}
+	return p;
+}
+
+void put_fragment(struct configfs_fragment *frag)
+{
+	if (frag && atomic_dec_and_test(&frag->frag_count))
+		kfree(frag);
+}
+
+struct configfs_fragment *get_fragment(struct configfs_fragment *frag)
+{
+	if (likely(frag))
+		atomic_inc(&frag->frag_count);
+	return frag;
+}
+
 /*
  * Allocates a new configfs_dirent and links it to the parent configfs_dirent
  */
 static struct configfs_dirent *configfs_new_dirent(struct configfs_dirent *parent_sd,
-						   void *element, int type)
+						   void *element, int type,
+						   struct configfs_fragment *frag)
 {
 	struct configfs_dirent * sd;
 
@@ -164,7 +190,6 @@ static struct configfs_dirent *configfs_new_dirent(struct configfs_dirent *paren
 		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;
@@ -175,6 +200,7 @@ static struct configfs_dirent *configfs_new_dirent(struct configfs_dirent *paren
 		kmem_cache_free(configfs_dir_cachep, sd);
 		return ERR_PTR(-ENOENT);
 	}
+	sd->s_frag = get_fragment(frag);
 	list_add(&sd->s_sibling, &parent_sd->s_children);
 	spin_unlock(&configfs_dirent_lock);
 
@@ -209,11 +235,11 @@ static int configfs_dirent_exists(struct configfs_dirent *parent_sd,
 
 int configfs_make_dirent(struct configfs_dirent * parent_sd,
 			 struct dentry * dentry, void * element,
-			 umode_t mode, int type)
+			 umode_t mode, int type, struct configfs_fragment *frag)
 {
 	struct configfs_dirent * sd;
 
-	sd = configfs_new_dirent(parent_sd, element, type);
+	sd = configfs_new_dirent(parent_sd, element, type, frag);
 	if (IS_ERR(sd))
 		return PTR_ERR(sd);
 
@@ -225,30 +251,16 @@ int configfs_make_dirent(struct configfs_dirent * parent_sd,
 	return 0;
 }
 
-static void init_dir(struct inode * inode)
+static void configfs_remove_dirent(struct dentry *dentry)
 {
-	inode->i_op = &configfs_dir_inode_operations;
-	inode->i_fop = &configfs_dir_operations;
-
-	/* directory inodes start off with i_nlink == 2 (for "." entry) */
-	inc_nlink(inode);
-}
-
-static void configfs_init_file(struct inode * inode)
-{
-	inode->i_size = PAGE_SIZE;
-	inode->i_fop = &configfs_file_operations;
-}
-
-static void configfs_init_bin_file(struct inode *inode)
-{
-	inode->i_size = 0;
-	inode->i_fop = &configfs_bin_file_operations;
-}
+	struct configfs_dirent *sd = dentry->d_fsdata;
 
-static void init_symlink(struct inode * inode)
-{
-	inode->i_op = &configfs_symlink_inode_operations;
+	if (!sd)
+		return;
+	spin_lock(&configfs_dirent_lock);
+	list_del_init(&sd->s_sibling);
+	spin_unlock(&configfs_dirent_lock);
+	configfs_put(sd);
 }
 
 /**
@@ -260,11 +272,13 @@ static void init_symlink(struct inode * inode)
  *	until it is validated by configfs_dir_set_ready()
  */
 
-static int configfs_create_dir(struct config_item *item, struct dentry *dentry)
+static int configfs_create_dir(struct config_item *item, struct dentry *dentry,
+				struct configfs_fragment *frag)
 {
 	int error;
 	umode_t mode = S_IFDIR| S_IRWXU | S_IRUGO | S_IXUGO;
 	struct dentry *p = dentry->d_parent;
+	struct inode *inode;
 
 	BUG_ON(!item);
 
@@ -273,25 +287,30 @@ static int configfs_create_dir(struct config_item *item, struct dentry *dentry)
 		return error;
 
 	error = configfs_make_dirent(p->d_fsdata, dentry, item, mode,
-				     CONFIGFS_DIR | CONFIGFS_USET_CREATING);
+				     CONFIGFS_DIR | CONFIGFS_USET_CREATING,
+				     frag);
 	if (unlikely(error))
 		return error;
 
 	configfs_set_dir_dirent_depth(p->d_fsdata, dentry->d_fsdata);
-	error = configfs_create(dentry, mode, init_dir);
-	if (!error) {
-		inc_nlink(d_inode(p));
-		item->ci_dentry = dentry;
-	} else {
-		struct configfs_dirent *sd = dentry->d_fsdata;
-		if (sd) {
-			spin_lock(&configfs_dirent_lock);
-			list_del_init(&sd->s_sibling);
-			spin_unlock(&configfs_dirent_lock);
-			configfs_put(sd);
-		}
-	}
-	return error;
+	inode = configfs_create(dentry, mode);
+	if (IS_ERR(inode))
+		goto out_remove;
+
+	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);
+	d_instantiate(dentry, inode);
+	/* already hashed */
+	dget(dentry);  /* pin directory dentries in core */
+	inc_nlink(d_inode(p));
+	item->ci_dentry = dentry;
+	return 0;
+
+out_remove:
+	configfs_remove_dirent(dentry);
+	return PTR_ERR(inode);
 }
 
 /*
@@ -332,40 +351,40 @@ int configfs_dirent_is_ready(struct configfs_dirent *sd)
 	return ret;
 }
 
-int configfs_create_link(struct configfs_symlink *sl,
-			 struct dentry *parent,
-			 struct dentry *dentry)
+int configfs_create_link(struct configfs_dirent *target, struct dentry *parent,
+		struct dentry *dentry, char *body)
 {
 	int err = 0;
 	umode_t mode = S_IFLNK | S_IRWXUGO;
+	struct configfs_dirent *p = parent->d_fsdata;
+	struct inode *inode;
 
-	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;
+	err = configfs_make_dirent(p, dentry, target, mode, CONFIGFS_ITEM_LINK,
+			p->s_frag);
+	if (err)
+		return err;
+
+	inode = configfs_create(dentry, mode);
+	if (IS_ERR(inode))
+		goto out_remove;
+
+	inode->i_link = body;
+	inode->i_op = &configfs_symlink_inode_operations;
+	d_instantiate(dentry, inode);
+	dget(dentry);  /* pin link dentries in core */
+	return 0;
+
+out_remove:
+	configfs_remove_dirent(dentry);
+	return PTR_ERR(inode);
 }
 
 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);
+	configfs_remove_dirent(d);
+
 	if (d_really_is_positive(d))
 		simple_rmdir(d_inode(parent),d);
 
@@ -406,20 +425,27 @@ static void configfs_remove_dir(struct config_item * item)
 static int configfs_attach_attr(struct configfs_dirent * sd, struct dentry * dentry)
 {
 	struct configfs_attribute * attr = sd->s_element;
-	int error;
+	struct inode *inode;
 
 	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)
+	inode = configfs_create(dentry, (attr->ca_mode & S_IALLUGO) | S_IFREG);
+	if (IS_ERR(inode)) {
 		configfs_put(sd);
-	return error;
+		return PTR_ERR(inode);
+	}
+	if (sd->s_type & CONFIGFS_ITEM_BIN_ATTR) {
+		inode->i_size = 0;
+		inode->i_fop = &configfs_bin_file_operations;
+	} else {
+		inode->i_size = PAGE_SIZE;
+		inode->i_fop = &configfs_file_operations;
+	}
+	d_add(dentry, inode);
+	return 0;
 }
 
 static struct dentry * configfs_lookup(struct inode *dir,
@@ -489,7 +515,7 @@ static int configfs_detach_prep(struct dentry *dentry, struct dentry **wait)
 	parent_sd->s_type |= CONFIGFS_USET_DROPPING;
 
 	ret = -EBUSY;
-	if (!list_empty(&parent_sd->s_links))
+	if (parent_sd->s_links)
 		goto out;
 
 	ret = 0;
@@ -599,7 +625,8 @@ static int populate_attrs(struct config_item *item)
 
 static int configfs_attach_group(struct config_item *parent_item,
 				 struct config_item *item,
-				 struct dentry *dentry);
+				 struct dentry *dentry,
+				 struct configfs_fragment *frag);
 static void configfs_detach_group(struct config_item *item);
 
 static void detach_groups(struct config_group *group)
@@ -647,7 +674,8 @@ static void detach_groups(struct config_group *group)
  * try using vfs_mkdir.  Just a thought.
  */
 static int create_default_group(struct config_group *parent_group,
-				struct config_group *group)
+				struct config_group *group,
+				struct configfs_fragment *frag)
 {
 	int ret;
 	struct configfs_dirent *sd;
@@ -663,7 +691,7 @@ static int create_default_group(struct config_group *parent_group,
 		d_add(child, NULL);
 
 		ret = configfs_attach_group(&parent_group->cg_item,
-					    &group->cg_item, child);
+					    &group->cg_item, child, frag);
 		if (!ret) {
 			sd = child->d_fsdata;
 			sd->s_type |= CONFIGFS_USET_DEFAULT;
@@ -677,13 +705,14 @@ static int create_default_group(struct config_group *parent_group,
 	return ret;
 }
 
-static int populate_groups(struct config_group *group)
+static int populate_groups(struct config_group *group,
+			   struct configfs_fragment *frag)
 {
 	struct config_group *new_group;
 	int ret = 0;
 
 	list_for_each_entry(new_group, &group->default_groups, group_entry) {
-		ret = create_default_group(group, new_group);
+		ret = create_default_group(group, new_group, frag);
 		if (ret) {
 			detach_groups(group);
 			break;
@@ -797,11 +826,12 @@ static void link_group(struct config_group *parent_group, struct config_group *g
  */
 static int configfs_attach_item(struct config_item *parent_item,
 				struct config_item *item,
-				struct dentry *dentry)
+				struct dentry *dentry,
+				struct configfs_fragment *frag)
 {
 	int ret;
 
-	ret = configfs_create_dir(item, dentry);
+	ret = configfs_create_dir(item, dentry, frag);
 	if (!ret) {
 		ret = populate_attrs(item);
 		if (ret) {
@@ -831,12 +861,13 @@ static void configfs_detach_item(struct config_item *item)
 
 static int configfs_attach_group(struct config_item *parent_item,
 				 struct config_item *item,
-				 struct dentry *dentry)
+				 struct dentry *dentry,
+				 struct configfs_fragment *frag)
 {
 	int ret;
 	struct configfs_dirent *sd;
 
-	ret = configfs_attach_item(parent_item, item, dentry);
+	ret = configfs_attach_item(parent_item, item, dentry, frag);
 	if (!ret) {
 		sd = dentry->d_fsdata;
 		sd->s_type |= CONFIGFS_USET_DIR;
@@ -852,7 +883,7 @@ static int configfs_attach_group(struct config_item *parent_item,
 		 */
 		inode_lock_nested(d_inode(dentry), I_MUTEX_CHILD);
 		configfs_adjust_dir_dirent_depth_before_populate(sd);
-		ret = populate_groups(to_config_group(item));
+		ret = populate_groups(to_config_group(item), frag);
 		if (ret) {
 			configfs_detach_item(item);
 			d_inode(dentry)->i_flags |= S_DEAD;
@@ -1247,6 +1278,7 @@ static int configfs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode
 	struct configfs_dirent *sd;
 	const struct config_item_type *type;
 	struct module *subsys_owner = NULL, *new_item_owner = NULL;
+	struct configfs_fragment *frag;
 	char *name;
 
 	sd = dentry->d_parent->d_fsdata;
@@ -1265,6 +1297,12 @@ static int configfs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode
 		goto out;
 	}
 
+	frag = new_fragment();
+	if (!frag) {
+		ret = -ENOMEM;
+		goto out;
+	}
+
 	/* Get a working ref for the duration of this function */
 	parent_item = configfs_get_config_item(dentry->d_parent);
 	type = parent_item->ci_type;
@@ -1367,9 +1405,9 @@ static int configfs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode
 	spin_unlock(&configfs_dirent_lock);
 
 	if (group)
-		ret = configfs_attach_group(parent_item, item, dentry);
+		ret = configfs_attach_group(parent_item, item, dentry, frag);
 	else
-		ret = configfs_attach_item(parent_item, item, dentry);
+		ret = configfs_attach_item(parent_item, item, dentry, frag);
 
 	spin_lock(&configfs_dirent_lock);
 	sd->s_type &= ~CONFIGFS_USET_IN_MKDIR;
@@ -1406,6 +1444,7 @@ out_put:
 	 * reference.
 	 */
 	config_item_put(parent_item);
+	put_fragment(frag);
 
 out:
 	return ret;
@@ -1417,6 +1456,7 @@ static int configfs_rmdir(struct inode *dir, struct dentry *dentry)
 	struct config_item *item;
 	struct configfs_subsystem *subsys;
 	struct configfs_dirent *sd;
+	struct configfs_fragment *frag;
 	struct module *subsys_owner = NULL, *dead_item_owner = NULL;
 	int ret;
 
@@ -1474,6 +1514,16 @@ static int configfs_rmdir(struct inode *dir, struct dentry *dentry)
 		}
 	} while (ret == -EAGAIN);
 
+	frag = sd->s_frag;
+	if (down_write_killable(&frag->frag_sem)) {
+		spin_lock(&configfs_dirent_lock);
+		configfs_detach_rollback(dentry);
+		spin_unlock(&configfs_dirent_lock);
+		return -EINTR;
+	}
+	frag->frag_dead = true;
+	up_write(&frag->frag_sem);
+
 	/* Get a working ref for the duration of this function */
 	item = configfs_get_config_item(dentry);
 
@@ -1523,44 +1573,6 @@ const struct inode_operations configfs_root_inode_operations = {
 	.setattr	= configfs_setattr,
 };
 
-#if 0
-int configfs_rename_dir(struct config_item * item, const char *new_name)
-{
-	int error = 0;
-	struct dentry * new_dentry, * parent;
-
-	if (!strcmp(config_item_name(item), new_name))
-		return -EINVAL;
-
-	if (!item->parent)
-		return -EINVAL;
-
-	down_write(&configfs_rename_sem);
-	parent = item->parent->dentry;
-
-	inode_lock(d_inode(parent));
-
-	new_dentry = lookup_one_len(new_name, parent, strlen(new_name));
-	if (!IS_ERR(new_dentry)) {
-		if (d_really_is_negative(new_dentry)) {
-			error = config_item_set_name(item, "%s", new_name);
-			if (!error) {
-				d_add(new_dentry, NULL);
-				d_move(item->dentry, new_dentry);
-			}
-			else
-				d_delete(new_dentry);
-		} else
-			error = -EEXIST;
-		dput(new_dentry);
-	}
-	inode_unlock(d_inode(parent));
-	up_write(&configfs_rename_sem);
-
-	return error;
-}
-#endif
-
 static int configfs_dir_open(struct inode *inode, struct file *file)
 {
 	struct dentry * dentry = file->f_path.dentry;
@@ -1574,7 +1586,7 @@ static int configfs_dir_open(struct inode *inode, struct file *file)
 	 */
 	err = -ENOENT;
 	if (configfs_dirent_is_ready(parent_sd)) {
-		file->private_data = configfs_new_dirent(parent_sd, NULL, 0);
+		file->private_data = configfs_new_dirent(parent_sd, NULL, 0, NULL);
 		if (IS_ERR(file->private_data))
 			err = PTR_ERR(file->private_data);
 		else
@@ -1732,8 +1744,13 @@ int configfs_register_group(struct config_group *parent_group,
 {
 	struct configfs_subsystem *subsys = parent_group->cg_subsys;
 	struct dentry *parent;
+	struct configfs_fragment *frag;
 	int ret;
 
+	frag = new_fragment();
+	if (!frag)
+		return -ENOMEM;
+
 	mutex_lock(&subsys->su_mutex);
 	link_group(parent_group, group);
 	mutex_unlock(&subsys->su_mutex);
@@ -1741,7 +1758,7 @@ int configfs_register_group(struct config_group *parent_group,
 	parent = parent_group->cg_item.ci_dentry;
 
 	inode_lock_nested(d_inode(parent), I_MUTEX_PARENT);
-	ret = create_default_group(parent_group, group);
+	ret = create_default_group(parent_group, group, frag);
 	if (ret)
 		goto err_out;
 
@@ -1749,12 +1766,14 @@ int configfs_register_group(struct config_group *parent_group,
 	configfs_dir_set_ready(group->cg_item.ci_dentry->d_fsdata);
 	spin_unlock(&configfs_dirent_lock);
 	inode_unlock(d_inode(parent));
+	put_fragment(frag);
 	return 0;
 err_out:
 	inode_unlock(d_inode(parent));
 	mutex_lock(&subsys->su_mutex);
 	unlink_group(group);
 	mutex_unlock(&subsys->su_mutex);
+	put_fragment(frag);
 	return ret;
 }
 EXPORT_SYMBOL(configfs_register_group);
@@ -1770,16 +1789,12 @@ void configfs_unregister_group(struct config_group *group)
 	struct configfs_subsystem *subsys = group->cg_subsys;
 	struct dentry *dentry = group->cg_item.ci_dentry;
 	struct dentry *parent = group->cg_item.ci_parent->ci_dentry;
+	struct configfs_dirent *sd = dentry->d_fsdata;
+	struct configfs_fragment *frag = sd->s_frag;
 
-	mutex_lock(&subsys->su_mutex);
-	if (!group->cg_item.ci_parent->ci_group) {
-		/*
-		 * The parent has already been unlinked and detached
-		 * due to a rmdir.
-		 */
-		goto unlink_group;
-	}
-	mutex_unlock(&subsys->su_mutex);
+	down_write(&frag->frag_sem);
+	frag->frag_dead = true;
+	up_write(&frag->frag_sem);
 
 	inode_lock_nested(d_inode(parent), I_MUTEX_PARENT);
 	spin_lock(&configfs_dirent_lock);
@@ -1796,7 +1811,6 @@ void configfs_unregister_group(struct config_group *group)
 	dput(dentry);
 
 	mutex_lock(&subsys->su_mutex);
-unlink_group:
 	unlink_group(group);
 	mutex_unlock(&subsys->su_mutex);
 }
@@ -1853,10 +1867,17 @@ int configfs_register_subsystem(struct configfs_subsystem *subsys)
 	struct dentry *dentry;
 	struct dentry *root;
 	struct configfs_dirent *sd;
+	struct configfs_fragment *frag;
+
+	frag = new_fragment();
+	if (!frag)
+		return -ENOMEM;
 
 	root = configfs_pin_fs();
-	if (IS_ERR(root))
+	if (IS_ERR(root)) {
+		put_fragment(frag);
 		return PTR_ERR(root);
+	}
 
 	if (!group->cg_item.ci_name)
 		group->cg_item.ci_name = group->cg_item.ci_namebuf;
@@ -1872,7 +1893,7 @@ int configfs_register_subsystem(struct configfs_subsystem *subsys)
 		d_add(dentry, NULL);
 
 		err = configfs_attach_group(sd->s_element, &group->cg_item,
-					    dentry);
+					    dentry, frag);
 		if (err) {
 			BUG_ON(d_inode(dentry));
 			d_drop(dentry);
@@ -1890,6 +1911,7 @@ int configfs_register_subsystem(struct configfs_subsystem *subsys)
 		unlink_group(group);
 		configfs_release_fs();
 	}
+	put_fragment(frag);
 
 	return err;
 }
@@ -1899,12 +1921,18 @@ void configfs_unregister_subsystem(struct configfs_subsystem *subsys)
 	struct config_group *group = &subsys->su_group;
 	struct dentry *dentry = group->cg_item.ci_dentry;
 	struct dentry *root = dentry->d_sb->s_root;
+	struct configfs_dirent *sd = dentry->d_fsdata;
+	struct configfs_fragment *frag = sd->s_frag;
 
 	if (dentry->d_parent != root) {
 		pr_err("Tried to unregister non-subsystem!\n");
 		return;
 	}
 
+	down_write(&frag->frag_sem);
+	frag->frag_dead = true;
+	up_write(&frag->frag_sem);
+
 	inode_lock_nested(d_inode(root),
 			  I_MUTEX_PARENT);
 	inode_lock_nested(d_inode(dentry), I_MUTEX_CHILD);