target/linux/generic/pending-4.4/110-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 @@ -35,7 +35,7 @@ static int jffs2_mkdir (struct inode *,s
  13  static int jffs2_rmdir (struct inode *,struct dentry *);
  14  static int jffs2_mknod (struct inode *,struct dentry *,umode_t,dev_t);
  15  static int jffs2_rename (struct inode *, struct dentry *,
  16 -                        struct inode *, struct dentry *);
  17 +                        struct inode *, struct dentry *, unsigned int);
  18
  19  const struct file_operations jffs2_dir_operations =
  20  {
  21 @@ -57,7 +57,7 @@ const struct inode_operations jffs2_dir_
  22         .mkdir =        jffs2_mkdir,
  23         .rmdir =        jffs2_rmdir,
  24         .mknod =        jffs2_mknod,
  25 -       .rename =       jffs2_rename,
  26 +       .rename2 =      jffs2_rename,
  27         .get_acl =      jffs2_get_acl,
  28         .set_acl =      jffs2_set_acl,
  29         .setattr =      jffs2_setattr,
  30 @@ -754,8 +754,27 @@ static int jffs2_mknod (struct inode *di
  31         return ret;
  32  }
  33
  34 +static int jffs2_whiteout(struct inode *old_dir, struct dentry *old_dentry)
  35 +{
  36 +       struct dentry *wh;
  37 +       int err;
  38 +
  39 +       wh = d_alloc(old_dentry->d_parent, &old_dentry->d_name);
  40 +       if (!wh)
  41 +               return -ENOMEM;
  42 +
  43 +       err = jffs2_mknod(old_dir, wh, S_IFCHR | WHITEOUT_MODE,
  44 +                         WHITEOUT_DEV);
  45 +       if (err)
  46 +               return err;
  47 +
  48 +       d_rehash(wh);
  49 +       return 0;
  50 +}
  51 +
  52  static int jffs2_rename (struct inode *old_dir_i, struct dentry *old_dentry,
  53 -                        struct inode *new_dir_i, struct dentry *new_dentry)
  54 +                        struct inode *new_dir_i, struct dentry *new_dentry,
  55 +                        unsigned int flags)
  56  {
  57         int ret;
  58         struct jffs2_sb_info *c = JFFS2_SB_INFO(old_dir_i->i_sb);
  59 @@ -763,6 +782,9 @@ static int jffs2_rename (struct inode *o
  60         uint8_t type;
  61         uint32_t now;
  62
  63 +       if (flags & ~RENAME_WHITEOUT)
  64 +               return -EINVAL;
  65 +
  66         /* The VFS will check for us and prevent trying to rename a
  67          * file over a directory and vice versa, but if it's a directory,
  68          * the VFS can't check whether the victim is empty. The filesystem
  69 @@ -826,9 +848,14 @@ static int jffs2_rename (struct inode *o
  70         if (d_is_dir(old_dentry) && !victim_f)
  71                 inc_nlink(new_dir_i);
  72
  73 -       /* Unlink the original */
  74 -       ret = jffs2_do_unlink(c, JFFS2_INODE_INFO(old_dir_i),
  75 -                             old_dentry->d_name.name, old_dentry->d_name.len, NULL, now);
  76 +       if (flags & RENAME_WHITEOUT)
  77 +               /* Replace with whiteout */
  78 +               ret = jffs2_whiteout(old_dir_i, old_dentry);
  79 +       else
  80 +               /* Unlink the original */
  81 +               ret = jffs2_do_unlink(c, JFFS2_INODE_INFO(old_dir_i),
  82 +                                     old_dentry->d_name.name,
  83 +                                     old_dentry->d_name.len, NULL, now);
  84
  85         /* We don't touch inode->i_nlink */
  86