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path: root/fs/configfs/symlink.c
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Diffstat (limited to 'fs/configfs/symlink.c')
-rw-r--r--fs/configfs/symlink.c26
1 files changed, 26 insertions, 0 deletions
diff --git a/fs/configfs/symlink.c b/fs/configfs/symlink.c
index 0004d18c40ac..bf74973b0492 100644
--- a/fs/configfs/symlink.c
+++ b/fs/configfs/symlink.c
@@ -31,6 +31,9 @@
#include <linux/configfs.h>
#include "configfs_internal.h"
+/* Protects attachments of new symlinks */
+DEFINE_MUTEX(configfs_symlink_mutex);
+
static int item_depth(struct config_item * item)
{
struct config_item * p = item;
@@ -73,11 +76,20 @@ static int create_link(struct config_item *parent_item,
struct configfs_symlink *sl;
int ret;
+ ret = -ENOENT;
+ if (!configfs_dirent_is_ready(target_sd))
+ goto out;
ret = -ENOMEM;
sl = kmalloc(sizeof(struct configfs_symlink), GFP_KERNEL);
if (sl) {
sl->sl_target = config_item_get(item);
spin_lock(&configfs_dirent_lock);
+ if (target_sd->s_type & CONFIGFS_USET_DROPPING) {
+ spin_unlock(&configfs_dirent_lock);
+ config_item_put(item);
+ kfree(sl);
+ return -ENOENT;
+ }
list_add(&sl->sl_list, &target_sd->s_links);
spin_unlock(&configfs_dirent_lock);
ret = configfs_create_link(sl, parent_item->ci_dentry,
@@ -91,6 +103,7 @@ static int create_link(struct config_item *parent_item,
}
}
+out:
return ret;
}
@@ -120,6 +133,7 @@ int configfs_symlink(struct inode *dir, struct dentry *dentry, const char *symna
{
int ret;
struct nameidata nd;
+ struct configfs_dirent *sd;
struct config_item *parent_item;
struct config_item *target_item;
struct config_item_type *type;
@@ -128,9 +142,19 @@ int configfs_symlink(struct inode *dir, struct dentry *dentry, const char *symna
if (dentry->d_parent == configfs_sb->s_root)
goto out;
+ sd = dentry->d_parent->d_fsdata;
+ /*
+ * Fake invisibility if dir belongs to a group/default groups hierarchy
+ * being attached
+ */
+ ret = -ENOENT;
+ if (!configfs_dirent_is_ready(sd))
+ goto out;
+
parent_item = configfs_get_config_item(dentry->d_parent);
type = parent_item->ci_type;
+ ret = -EPERM;
if (!type || !type->ct_item_ops ||
!type->ct_item_ops->allow_link)
goto out_put;
@@ -141,7 +165,9 @@ int configfs_symlink(struct inode *dir, struct dentry *dentry, const char *symna
ret = type->ct_item_ops->allow_link(parent_item, target_item);
if (!ret) {
+ mutex_lock(&configfs_symlink_mutex);
ret = create_link(parent_item, target_item, dentry);
+ mutex_unlock(&configfs_symlink_mutex);
if (ret && type->ct_item_ops->drop_link)
type->ct_item_ops->drop_link(parent_item,
target_item);