target/linux/generic/patches-4.4/052-01-ubifs-Implement-O_TMPFILE.patch

   1 From: Richard Weinberger <richard@nod.at>
   2 Date: Tue, 13 Sep 2016 16:18:55 +0200
   3 Subject: [PATCH] ubifs: Implement O_TMPFILE
   4
   5 This patchs adds O_TMPFILE support to UBIFS.
   6 A temp file is a reference to an unlinked inode, a user
   7 holding the reference can use it. As soon it is being closed
   8 all data vanishes.
   9
  10 Signed-off-by: Richard Weinberger <richard@nod.at>
  11 ---
  12
  13 --- a/fs/ubifs/dir.c
  14 +++ b/fs/ubifs/dir.c
  15 @@ -301,6 +301,76 @@ out_budg:
  16         return err;
  17  }
  18
  19 +static int ubifs_tmpfile(struct inode *dir, struct dentry *dentry,
  20 +                        umode_t mode)
  21 +{
  22 +       struct inode *inode;
  23 +       struct ubifs_info *c = dir->i_sb->s_fs_info;
  24 +       struct ubifs_budget_req req = { .new_ino = 1, .new_dent = 1};
  25 +       struct ubifs_budget_req ino_req = { .dirtied_ino = 1 };
  26 +       struct ubifs_inode *ui, *dir_ui = ubifs_inode(dir);
  27 +       int err, instantiated = 0;
  28 +
  29 +       /*
  30 +        * Budget request settings: new dirty inode, new direntry,
  31 +        * budget for dirtied inode will be released via writeback.
  32 +        */
  33 +
  34 +       dbg_gen("dent '%pd', mode %#hx in dir ino %lu",
  35 +               dentry, mode, dir->i_ino);
  36 +
  37 +       err = ubifs_budget_space(c, &req);
  38 +       if (err)
  39 +               return err;
  40 +
  41 +       err = ubifs_budget_space(c, &ino_req);
  42 +       if (err) {
  43 +               ubifs_release_budget(c, &req);
  44 +               return err;
  45 +       }
  46 +
  47 +       inode = ubifs_new_inode(c, dir, mode);
  48 +       if (IS_ERR(inode)) {
  49 +               err = PTR_ERR(inode);
  50 +               goto out_budg;
  51 +       }
  52 +       ui = ubifs_inode(inode);
  53 +
  54 +       err = ubifs_init_security(dir, inode, &dentry->d_name);
  55 +       if (err)
  56 +               goto out_inode;
  57 +
  58 +       mutex_lock(&ui->ui_mutex);
  59 +       insert_inode_hash(inode);
  60 +       d_tmpfile(dentry, inode);
  61 +       ubifs_assert(ui->dirty);
  62 +       instantiated = 1;
  63 +       mutex_unlock(&ui->ui_mutex);
  64 +
  65 +       mutex_lock(&dir_ui->ui_mutex);
  66 +       err = ubifs_jnl_update(c, dir, &dentry->d_name, inode, 1, 0);
  67 +       if (err)
  68 +               goto out_cancel;
  69 +       mutex_unlock(&dir_ui->ui_mutex);
  70 +
  71 +       ubifs_release_budget(c, &req);
  72 +
  73 +       return 0;
  74 +
  75 +out_cancel:
  76 +       mutex_unlock(&dir_ui->ui_mutex);
  77 +out_inode:
  78 +       make_bad_inode(inode);
  79 +       if (!instantiated)
  80 +               iput(inode);
  81 +out_budg:
  82 +       ubifs_release_budget(c, &req);
  83 +       if (!instantiated)
  84 +               ubifs_release_budget(c, &ino_req);
  85 +       ubifs_err(c, "cannot create temporary file, error %d", err);
  86 +       return err;
  87 +}
  88 +
  89  /**
  90   * vfs_dent_type - get VFS directory entry type.
  91   * @type: UBIFS directory entry type
  92 @@ -1195,6 +1265,7 @@ const struct inode_operations ubifs_dir_
  93  #ifdef CONFIG_UBIFS_ATIME_SUPPORT
  94         .update_time = ubifs_update_time,
  95  #endif
  96 +       .tmpfile     = ubifs_tmpfile,
  97  };
  98
  99  const struct file_operations ubifs_dir_operations = {