target/linux/generic/patches-4.9/140-jffs2-use-.rename2-and-add-RENAME_WHITEOUT-support.patch

   1 From: Felix Fietkau <nbd@nbd.name>
   2 Date: Fri, 10 Apr 2015 13:35:29 +0200
   3 Subject: [PATCH] jffs2: use .rename2 and add RENAME_WHITEOUT support
   4
   5 It is required for renames on overlayfs
   6
   7 Signed-off-by: Felix Fietkau <nbd@nbd.name>
   8 ---
   9
  10 --- a/fs/jffs2/dir.c
  11 +++ b/fs/jffs2/dir.c
  12 @@ -756,6 +756,24 @@ static int jffs2_mknod (struct inode *di
  13         return ret;
  14  }
  15
  16 +static int jffs2_whiteout (struct inode *old_dir, struct dentry *old_dentry)
  17 +{
  18 +       struct dentry *wh;
  19 +       int err;
  20 +
  21 +       wh = d_alloc(old_dentry->d_parent, &old_dentry->d_name);
  22 +       if (!wh)
  23 +               return -ENOMEM;
  24 +
  25 +       err = jffs2_mknod(old_dir, wh, S_IFCHR | WHITEOUT_MODE,
  26 +                         WHITEOUT_DEV);
  27 +       if (err)
  28 +               return err;
  29 +
  30 +       d_rehash(wh);
  31 +       return 0;
  32 +}
  33 +
  34  static int jffs2_rename (struct inode *old_dir_i, struct dentry *old_dentry,
  35                          struct inode *new_dir_i, struct dentry *new_dentry,
  36                          unsigned int flags)
  37 @@ -766,7 +784,7 @@ static int jffs2_rename (struct inode *o
  38         uint8_t type;
  39         uint32_t now;
  40
  41 -       if (flags & ~RENAME_NOREPLACE)
  42 +       if (flags & ~(RENAME_NOREPLACE|RENAME_WHITEOUT))
  43                 return -EINVAL;
  44
  45         /* The VFS will check for us and prevent trying to rename a
  46 @@ -832,9 +850,14 @@ static int jffs2_rename (struct inode *o
  47         if (d_is_dir(old_dentry) && !victim_f)
  48                 inc_nlink(new_dir_i);
  49
  50 -       /* Unlink the original */
  51 -       ret = jffs2_do_unlink(c, JFFS2_INODE_INFO(old_dir_i),
  52 -                             old_dentry->d_name.name, old_dentry->d_name.len, NULL, now);
  53 +       if (flags & RENAME_WHITEOUT)
  54 +               /* Replace with whiteout */
  55 +               ret = jffs2_whiteout(old_dir_i, old_dentry);
  56 +       else
  57 +               /* Unlink the original */
  58 +               ret = jffs2_do_unlink(c, JFFS2_INODE_INFO(old_dir_i),
  59 +                                     old_dentry->d_name.name,
  60 +                                     old_dentry->d_name.len, NULL, now);
  61
  62         /* We don't touch inode->i_nlink */
  63