Merge branch 'x86-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git...

[linux-2.6] / fs / configfs / symlink.c

diff --git a/fs/configfs/symlink.c b/fs/configfs/symlink.c
index c12801a12c3478b72b2b75ec69682a724304684f..bf74973b0492372d65aafaeb0fa8af496979c54c 100644 (file)
--- 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;
@@ -73,6 +76,9 @@ 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) {
@@ -97,6 +103,7 @@ static int create_link(struct config_item *parent_item,
                }
        }
 
+out:
        return ret;
 }
 
@@ -126,6 +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;
@@ -134,9 +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;
@@ -147,7 +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);