ecryptfs: dont call lookup_one_len to avoid NULL nameidata

[net-next-2.6.git] / fs / ecryptfs / inode.c

diff --git a/fs/ecryptfs/inode.c b/fs/ecryptfs/inode.c
index 8cd617b66baa0e6328d7e5f8afe4a6147fb64792..a8acfc5d34765f940c9a03f4ce864e1b84be846f 100644 (file)
--- a/fs/ecryptfs/inode.c
+++ b/fs/ecryptfs/inode.c
@@ -347,6 +347,76 @@ out:
        return rc;
 }
 
+/**
+ * ecryptfs_new_lower_dentry
+ * @ename: The name of the new dentry.
+ * @lower_dir_dentry: Parent directory of the new dentry.
+ * @nd: nameidata from last lookup.
+ *
+ * Create a new dentry or get it from lower parent dir.
+ */
+static struct dentry *
+ecryptfs_new_lower_dentry(struct qstr *name, struct dentry *lower_dir_dentry,
+                         struct nameidata *nd)
+{
+       struct dentry *new_dentry;
+       struct dentry *tmp;
+       struct inode *lower_dir_inode;
+
+       lower_dir_inode = lower_dir_dentry->d_inode;
+
+       tmp = d_alloc(lower_dir_dentry, name);
+       if (!tmp)
+               return ERR_PTR(-ENOMEM);
+
+       mutex_lock(&lower_dir_inode->i_mutex);
+       new_dentry = lower_dir_inode->i_op->lookup(lower_dir_inode, tmp, nd);
+       mutex_unlock(&lower_dir_inode->i_mutex);
+
+       if (!new_dentry)
+               new_dentry = tmp;
+       else
+               dput(tmp);
+
+       return new_dentry;
+}
+
+
+/**
+ * ecryptfs_lookup_one_lower
+ * @ecryptfs_dentry: The eCryptfs dentry that we are looking up
+ * @lower_dir_dentry: lower parent directory
+ *
+ * Get the lower dentry from vfs. If lower dentry does not exist yet,
+ * create it.
+ */
+static struct dentry *
+ecryptfs_lookup_one_lower(struct dentry *ecryptfs_dentry,
+                         struct dentry *lower_dir_dentry)
+{
+       struct nameidata nd;
+       struct vfsmount *lower_mnt;
+       struct qstr *name;
+       int err;
+
+       name = &ecryptfs_dentry->d_name;
+       lower_mnt = mntget(ecryptfs_dentry_to_lower_mnt(
+                                   ecryptfs_dentry->d_parent));
+       err = vfs_path_lookup(lower_dir_dentry, lower_mnt, name->name , 0, &nd);
+       mntput(lower_mnt);
+
+       if (!err) {
+               /* we dont need the mount */
+               mntput(nd.path.mnt);
+               return nd.path.dentry;
+       }
+       if (err != -ENOENT)
+               return ERR_PTR(err);
+
+       /* create a new lower dentry */
+       return ecryptfs_new_lower_dentry(name, lower_dir_dentry, &nd);
+}
+
 /**
  * ecryptfs_lookup
  * @ecryptfs_dir_inode: The eCryptfs directory inode
@@ -374,14 +444,12 @@ static struct dentry *ecryptfs_lookup(struct inode *ecryptfs_dir_inode,
                goto out_d_drop;
        }
        lower_dir_dentry = ecryptfs_dentry_to_lower(ecryptfs_dentry->d_parent);
-       mutex_lock(&lower_dir_dentry->d_inode->i_mutex);
-       lower_dentry = lookup_one_len(ecryptfs_dentry->d_name.name,
-                                     lower_dir_dentry,
-                                     ecryptfs_dentry->d_name.len);
-       mutex_unlock(&lower_dir_dentry->d_inode->i_mutex);
+
+       lower_dentry = ecryptfs_lookup_one_lower(ecryptfs_dentry,
+                                                lower_dir_dentry);
        if (IS_ERR(lower_dentry)) {
                rc = PTR_ERR(lower_dentry);
-               ecryptfs_printk(KERN_DEBUG, "%s: lookup_one_len() returned "
+               ecryptfs_printk(KERN_DEBUG, "%s: lookup_one_lower() returned "
                                "[%d] on lower_dentry = [%s]\n", __func__, rc,
                                encrypted_and_encoded_name);
                goto out_d_drop;
@@ -403,14 +471,11 @@ static struct dentry *ecryptfs_lookup(struct inode *ecryptfs_dir_inode,
                       "filename; rc = [%d]\n", __func__, rc);
                goto out_d_drop;
        }
-       mutex_lock(&lower_dir_dentry->d_inode->i_mutex);
-       lower_dentry = lookup_one_len(encrypted_and_encoded_name,
-                                     lower_dir_dentry,
-                                     encrypted_and_encoded_name_size - 1);
-       mutex_unlock(&lower_dir_dentry->d_inode->i_mutex);
+       lower_dentry = ecryptfs_lookup_one_lower(ecryptfs_dentry,
+                                                lower_dir_dentry);
        if (IS_ERR(lower_dentry)) {
                rc = PTR_ERR(lower_dentry);
-               ecryptfs_printk(KERN_DEBUG, "%s: lookup_one_len() returned "
+               ecryptfs_printk(KERN_DEBUG, "%s: lookup_one_lower() returned "
                                "[%d] on lower_dentry = [%s]\n", __func__, rc,
                                encrypted_and_encoded_name);
                goto out_d_drop;