change system file

hc

2024-10-09 244b2c5ca8b14627e4a17755e5922221e121c771

 kernel/fs/configfs/symlink.c
..
..
@@ -1,22 +1,8 @@
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+// SPDX-License-Identifier: GPL-2.0-or-later
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 /* -*- mode: c; c-basic-offset: 8; -*-
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  * vim: noexpandtab sw=8 ts=8 sts=0:
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  *
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  * symlink.c - operations for configfs symlinks.
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- *
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- * This program is free software; you can redistribute it and/or
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- * modify it under the terms of the GNU General Public
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- * License as published by the Free Software Foundation; either
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- * version 2 of the License, or (at your option) any later version.
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- *
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- * This program is distributed in the hope that it will be useful,
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- * but WITHOUT ANY WARRANTY; without even the implied warranty of
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- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
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- * General Public License for more details.
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- *
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- * You should have received a copy of the GNU General Public
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- * License along with this program; if not, write to the
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- * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
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- * Boston, MA 021110-1307, USA.
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  *
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  * Based on sysfs:
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  * 	sysfs is Copyright (C) 2001, 2002, 2003 Patrick Mochel
..
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@@ -69,41 +55,63 @@
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 	}
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 }
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+static int configfs_get_target_path(struct config_item *item,
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+		struct config_item *target, char *path)
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+{
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+	int depth, size;
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+	char *s;
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+
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+	depth = item_depth(item);
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+	size = item_path_length(target) + depth * 3 - 1;
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+	if (size > PATH_MAX)
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+		return -ENAMETOOLONG;
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+
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+	pr_debug("%s: depth = %d, size = %d\n", __func__, depth, size);
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+
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+	for (s = path; depth--; s += 3)
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+		strcpy(s,"../");
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+
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+	fill_item_path(target, path, size);
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+	pr_debug("%s: path = '%s'\n", __func__, path);
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+	return 0;
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+}
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+
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 static int create_link(struct config_item *parent_item,
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 		       struct config_item *item,
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 		       struct dentry *dentry)
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 {
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 	struct configfs_dirent *target_sd = item->ci_dentry->d_fsdata;
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-	struct configfs_symlink *sl;
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+	char *body;
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 	int ret;
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-	ret = -ENOENT;
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 	if (!configfs_dirent_is_ready(target_sd))
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-		goto out;
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-	ret = -ENOMEM;
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-	sl = kmalloc(sizeof(struct configfs_symlink), GFP_KERNEL);
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-	if (sl) {
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-		spin_lock(&configfs_dirent_lock);
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-		if (target_sd->s_type & CONFIGFS_USET_DROPPING) {
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-			spin_unlock(&configfs_dirent_lock);
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-			kfree(sl);
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-			return -ENOENT;
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-		}
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-		sl->sl_target = config_item_get(item);
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-		list_add(&sl->sl_list, &target_sd->s_links);
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-		spin_unlock(&configfs_dirent_lock);
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-		ret = configfs_create_link(sl, parent_item->ci_dentry,
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-					   dentry);
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-		if (ret) {
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-			spin_lock(&configfs_dirent_lock);
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-			list_del_init(&sl->sl_list);
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-			spin_unlock(&configfs_dirent_lock);
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-			config_item_put(item);
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-			kfree(sl);
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-		}
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-	}
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+		return -ENOENT;
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-out:
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+	body = kzalloc(PAGE_SIZE, GFP_KERNEL);
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+	if (!body)
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+		return -ENOMEM;
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+
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+	configfs_get(target_sd);
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+	spin_lock(&configfs_dirent_lock);
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+	if (target_sd->s_type & CONFIGFS_USET_DROPPING) {
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+		spin_unlock(&configfs_dirent_lock);
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+		configfs_put(target_sd);
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+		kfree(body);
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+		return -ENOENT;
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+	}
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+	target_sd->s_links++;
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+	spin_unlock(&configfs_dirent_lock);
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+	ret = configfs_get_target_path(parent_item, item, body);
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+	if (!ret)
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+		ret = configfs_create_link(target_sd, parent_item->ci_dentry,
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+					   dentry, body);
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+	if (ret) {
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+		spin_lock(&configfs_dirent_lock);
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+		target_sd->s_links--;
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+		spin_unlock(&configfs_dirent_lock);
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+		configfs_put(target_sd);
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+		kfree(body);
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+	}
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 	return ret;
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 }
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@@ -145,9 +153,8 @@
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 	 * Fake invisibility if dir belongs to a group/default groups hierarchy
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 	 * being attached
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 	 */
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-	ret = -ENOENT;
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 	if (!configfs_dirent_is_ready(sd))
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-		goto out;
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+		return -ENOENT;
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 	parent_item = configfs_get_config_item(dentry->d_parent);
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 	type = parent_item->ci_type;
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@@ -207,15 +214,12 @@
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 out_put:
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 	config_item_put(parent_item);
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-
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-out:
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 	return ret;
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 }
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 int configfs_unlink(struct inode *dir, struct dentry *dentry)
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 {
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-	struct configfs_dirent *sd = dentry->d_fsdata;
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-	struct configfs_symlink *sl;
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+	struct configfs_dirent *sd = dentry->d_fsdata, *target_sd;
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 	struct config_item *parent_item;
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 	const struct config_item_type *type;
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 	int ret;
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@@ -224,7 +228,7 @@
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 	if (!(sd->s_type & CONFIGFS_ITEM_LINK))
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 		goto out;
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-	sl = sd->s_element;
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+	target_sd = sd->s_element;
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 	parent_item = configfs_get_config_item(dentry->d_parent);
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 	type = parent_item->ci_type;
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@@ -238,21 +242,18 @@
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 	/*
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 	 * drop_link() must be called before
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-	 * list_del_init(&sl->sl_list), so that the order of
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+	 * decrementing target's ->s_links, so that the order of
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 	 * drop_link(this, target) and drop_item(target) is preserved.
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 	 */
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 	if (type && type->ct_item_ops &&
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 	    type->ct_item_ops->drop_link)
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 		type->ct_item_ops->drop_link(parent_item,
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-					       sl->sl_target);
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+					       target_sd->s_element);
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 	spin_lock(&configfs_dirent_lock);
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-	list_del_init(&sl->sl_list);
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+	target_sd->s_links--;
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 	spin_unlock(&configfs_dirent_lock);
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-
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-	/* Put reference from create_link() */
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-	config_item_put(sl->sl_target);
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-	kfree(sl);
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+	configfs_put(target_sd);
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 	config_item_put(parent_item);
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@@ -262,79 +263,8 @@
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 	return ret;
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 }
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-static int configfs_get_target_path(struct config_item * item, struct config_item * target,
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-				   char *path)
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-{
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-	char * s;
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-	int depth, size;
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-
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-	depth = item_depth(item);
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-	size = item_path_length(target) + depth * 3 - 1;
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-	if (size > PATH_MAX)
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-		return -ENAMETOOLONG;
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-
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-	pr_debug("%s: depth = %d, size = %d\n", __func__, depth, size);
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-
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-	for (s = path; depth--; s += 3)
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-		strcpy(s,"../");
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-
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-	fill_item_path(target, path, size);
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-	pr_debug("%s: path = '%s'\n", __func__, path);
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-
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-	return 0;
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-}
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-
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-static int configfs_getlink(struct dentry *dentry, char * path)
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-{
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-	struct config_item *item, *target_item;
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-	int error = 0;
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-
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-	item = configfs_get_config_item(dentry->d_parent);
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-	if (!item)
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-		return -EINVAL;
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-
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-	target_item = configfs_get_config_item(dentry);
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-	if (!target_item) {
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-		config_item_put(item);
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-		return -EINVAL;
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-	}
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-
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-	down_read(&configfs_rename_sem);
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-	error = configfs_get_target_path(item, target_item, path);
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-	up_read(&configfs_rename_sem);
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-
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-	config_item_put(item);
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-	config_item_put(target_item);
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-	return error;
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-
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-}
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-
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-static const char *configfs_get_link(struct dentry *dentry,
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-				     struct inode *inode,
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-				     struct delayed_call *done)
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-{
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-	char *body;
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-	int error;
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-
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-	if (!dentry)
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-		return ERR_PTR(-ECHILD);
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-
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-	body = kzalloc(PAGE_SIZE, GFP_KERNEL);
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-	if (!body)
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-		return ERR_PTR(-ENOMEM);
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-
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-	error = configfs_getlink(dentry, body);
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-	if (!error) {
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-		set_delayed_call(done, kfree_link, body);
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-		return body;
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-	}
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-
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-	kfree(body);
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-	return ERR_PTR(error);
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-}
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-
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 const struct inode_operations configfs_symlink_inode_operations = {
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-	.get_link = configfs_get_link,
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+	.get_link = simple_get_link,
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 	.setattr = configfs_setattr,
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 };
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