ubifs: Implement O_TMPFILE

This patchs adds O_TMPFILE support to UBIFS.
A temp file is a reference to an unlinked inode, a user
holding the reference can use it. As soon it is being closed
all data vanishes.

Signed-off-by: Richard Weinberger <richard@nod.at>

diff --git a/fs/ubifs/dir.c b/fs/ubifs/dir.c
index 4b86d3a738e1807c667fb6736f1deaa28a93d429..8460f481eeb9ce0589304803dff34b7f3471328e 100644 (file)
--- a/fs/ubifs/dir.c
+++ b/fs/ubifs/dir.c
@@ -301,6 +301,76 @@ out_budg:
        return err;
 }
 
+static int ubifs_tmpfile(struct inode *dir, struct dentry *dentry,
+                        umode_t mode)
+{
+       struct inode *inode;
+       struct ubifs_info *c = dir->i_sb->s_fs_info;
+       struct ubifs_budget_req req = { .new_ino = 1, .new_dent = 1};
+       struct ubifs_budget_req ino_req = { .dirtied_ino = 1 };
+       struct ubifs_inode *ui, *dir_ui = ubifs_inode(dir);
+       int err, instantiated = 0;
+
+       /*
+        * Budget request settings: new dirty inode, new direntry,
+        * budget for dirtied inode will be released via writeback.
+        */
+
+       dbg_gen("dent '%pd', mode %#hx in dir ino %lu",
+               dentry, mode, dir->i_ino);
+
+       err = ubifs_budget_space(c, &req);
+       if (err)
+               return err;
+
+       err = ubifs_budget_space(c, &ino_req);
+       if (err) {
+               ubifs_release_budget(c, &req);
+               return err;
+       }
+
+       inode = ubifs_new_inode(c, dir, mode);
+       if (IS_ERR(inode)) {
+               err = PTR_ERR(inode);
+               goto out_budg;
+       }
+       ui = ubifs_inode(inode);
+
+       err = ubifs_init_security(dir, inode, &dentry->d_name);
+       if (err)
+               goto out_inode;
+
+       mutex_lock(&ui->ui_mutex);
+       insert_inode_hash(inode);
+       d_tmpfile(dentry, inode);
+       ubifs_assert(ui->dirty);
+       instantiated = 1;
+       mutex_unlock(&ui->ui_mutex);
+
+       mutex_lock(&dir_ui->ui_mutex);
+       err = ubifs_jnl_update(c, dir, &dentry->d_name, inode, 1, 0);
+       if (err)
+               goto out_cancel;
+       mutex_unlock(&dir_ui->ui_mutex);
+
+       ubifs_release_budget(c, &req);
+
+       return 0;
+
+out_cancel:
+       mutex_unlock(&dir_ui->ui_mutex);
+out_inode:
+       make_bad_inode(inode);
+       if (!instantiated)
+               iput(inode);
+out_budg:
+       ubifs_release_budget(c, &req);
+       if (!instantiated)
+               ubifs_release_budget(c, &ino_req);
+       ubifs_err(c, "cannot create temporary file, error %d", err);
+       return err;
+}
+
 /**
  * vfs_dent_type - get VFS directory entry type.
  * @type: UBIFS directory entry type
@@ -1189,6 +1259,7 @@ const struct inode_operations ubifs_dir_inode_operations = {
 #ifdef CONFIG_UBIFS_ATIME_SUPPORT
        .update_time = ubifs_update_time,
 #endif
+       .tmpfile     = ubifs_tmpfile,
 };
 
 const struct file_operations ubifs_dir_operations = {